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Green-Witch
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- Jaipur
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- I am an under grad of Architecture at M-NIT, Jaipur. I'm involved in research in the field of environment, green architecture, green energy and kyoto protocol.
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Sweet Plant - Stevia
There's a new kid on the block (well, kind-of new to some of us anyway) ... stevia. This intriguing sweetener is ages old in some parts of the world – mostly South America and China, but relatively new in the U.S. It has no calories, no nothing that can harm you, even if you have diabetes. It is not processed like high-fructose corn syrup or agave nectar, and the final sweetener is totally unharmed in the extracting process.It is made from a shrub that is relatively easy to grow – that grew to…
The World Will End in 2012 - Is It True ?
the world doesnt end by 2012 but if we dont act to save earth due to global warming and green house effect polar ice caps melt,etc.................,will happen.it destroys the life of creatures.so let us save earth by contributing our efforts.Career in Environment
I can give you some suggestion like there is some conservation course available in the Indian institute of wildlife Dehradoon which is a very prestegious one also i think you should contact this institute apart from this there is one more institute in Banglore which has very tough competition to get in if you want further information about this institute then please make contact on this e-mail mahi.puri@gmail.com. Mahi is freind and ex coleague of mine, she has just given an entrance exam for th…© 2009 Created by Earth Matters Foundation on Ning. Create Your Own Social Network
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The most interesting fuel cells for the near future are modified hydrogen-oxygen (or air) cells, in which a gaseous or liquid hydrocarbon is the source of hydrogen.
Eventually, coal may serve as the primary energy source for fuel cells.
Cells based on fossil fuels have three main components :
(1) The fuel processor which converts the fossil fuel into a hydrogen-rich gas,
(2) The power section consisting of the actual fuel cell (or combination of cells), and
(3) The inverter for changing the direct current generated by the fuel cell into alternating current to be transmitted to user.
Main components of fuel cell system are shown schematically in Fig. (10.2.4.2). The most highly developed fossil fuel cells are phosphoric acid cells, molten carbonate cells, solid oxide electrolyte cell.
In phosphoric acid cell utilizes a concentrated acqueous solution of phosphoric acid as the electrolyte.
The primary fuel is light hydrocarbon, such natural gas or naphtha.
The operating temperature is 150 to 200°C and the discharge voltage is 0.7 to 0.8 volt.
Each cell unit is only a few millimeters thick so that a large number can be stacked in a package of reasonable size to produce the desired voltage and power
ADVANTAGES
. It is a direct conversion process and does not involve a thermal process, so it has high operating efficiency. Present day fuel cell efficiency is 38% and it is expected to reach 60%.
2. The unit is lighter, smaller, operate quitely, require little attention and less maintenance.
. Fuel power plants may further cut generation costs by reducing transmission losses.
4. Little pollution, little noise, so that it can be readily acceptable in residential areas.
5. The advantage of ammonia as fuel is that it can be stored in the liquid form.
6. Fuel cells can be installed near the use point, thus reducing electrical transmission requirements and accompanying losses. Consequently considerably higher efficiencies are possible.
Atmospheric pollution is small if the primary energy source is hydrogen, the only waste product is water ; if the source is a hydrocarbon, carbon dioxide is also produced, Nitrogen oxides, such as accompany combustion of fossil fuels in the air, are not formed in the fuel cell. Some heat is generated by a fuel cell, but it can be dissipated to the atmosphere or possibles used locally.
There is no requirement for large volumes of cooling water such as are necessary to condense exhaust system from a turbine in conventional power plant.
(9) As fuel cells do not make noise, they can be readily accepted in residential areas.
(10) The fuel cell takes little time to go into operation.
(11) The space requirement for fuel cell power plant is considerably less as compared to conventional power plants.
DRAWBACKS
Basic drawback of H2—02 cell is that Hydrogen and Oxygen are gases, so there is storage difficulty.
The primary drawbacks of fuel cells are, their low voltage, high initial costs and low service life.
-The difference between the theoretical voltage and the actual voltage is known as the polarisation.
-The effect of polarisation is to reduce the efficiency of the cell from the theoretical maximum.
-The significant drop in voltage and hence energy loss takes place as the current density is increased as shown in Fig.
ACTIVATION POLARIZATION
(CHEMICAL POLARIZATION)
-This is related to the activation energy barrier for the electron transfer process at the electrode. In fuel cells electrons are liberated and reaction is chemisorption reaction.
-At low current densities significant number of electrons are not emitted, which results in such a potential loss.
-This process requires that certain minimum activation energy supplied so that sufficient number of electrons are emitted, this energy is supplied by output of the cell. This loss is known as activation or chemical polarisation.
-This polarisation may be reduced by using better electrode catalysts, increasing surface area, and by raising the operating temperature.
How are you dear ? I am a new member of Em web. This is Sabrar from HYDERABAD (CITY OF PEARLS). I heart that your are doing campaign in Jaipur. All the best for your campaign in Jaipur and you will get success.
Wish you all the best.
Really sorry but I cant help this time. Hope you understand.
Regarsds,
Have u posted the invitations to the ones who are from Jaipur from members lists...if not please search for it....
I will also try to post the invitation to them.....and also to other friends...on other sites...Don't worry U will achieve the success....All The Best...tc....
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