TRIPLE H-WRESTLING

TRIPLE H-WRESTLING:

Paul Michael Levesque (born July 27, 1969), better known by his ring name Triple H (an abbreviation of his original WWE ring name Hunter Hearst Helmsley), is an American business executive and professional wrestLING

Triple H Says...

"I'm glad the fans enjoy what I do and that they love hating me. The heat I generate is the ultimate compliment. That's the stuff that makes me go 'great'!"

CHESS GAME-THEORY

CHESS GAME-THEORY:

Mathematics In The Game Of Chess

Legend has it that the game was invented by a mathematician in India who elicited a huge reward for its creation. The King of India was so impressed with the game that he asked the mathematician to name a prize as reward. Not wishing to appear greedy, the mathematician asked for one grain of rice to be placed on the first square of the chess board, two grains on the second, four on the third and so on. The number of grains of rice should be doubled each time.

The King thought that he'd got away lightly, but little did he realise the power of doubling to make things big very quickly. By the sixteenth square there was already a kilo of rice on the chess board. By the twentieth square his servant needed to bring in a wheelbarrow of rice. He never reached the 64th and last square on the board. By that point the rice on the board would have totalled a staggering 18,446,744,073,709,551,615 grains.

Playing chess has strong resonances with doing mathematics. There are simple rules for the way each chess piece moves but beyond these basic constraints, the pieces can roam freely across the board. Mathematics also proceeds by taking self-evident truths (called axioms) about properties of numbers and geometry and then by applying basic rules of logic you proceed to move mathematics from its starting point to deduce new statements about numbers and geometry. For example, using the moves allowed by mathematics the 18th-century mathematician Lagrange reached an endgame that showed that every number can be written as the sum of four square numbers, a far from obvious fact. For example, 310 = 172 +42 + 22 + 12.

Some mathematicians have turned their analytic skills on the game of chess itself. A classic problem called the Knight's Tour asks whether it is possible to use a knight to jump around the chess board visiting each square once only. The first examples were documented in a 9th-century Arabic manuscript. It is only within the past decade that mathematical techniques have been developed to count exactly how many such tours are possible.

It isn't just mathematicians and chess players who have been fascinated by the Knight's Tour. The highly styled Sanskrit poem Kavyalankara presents the Knight's Tour in verse form. And in the 20th century, the French author Georges Perec's novel Life: A User's Manual describes an apartment with 100 rooms arranged in a 10x10 grid. In the novel the order that the author visits the rooms is determined by a Knight's Tour on a 10x10 chessboard.

Mathematicians have also analysed just how many games of chess are possible. If you were to line up chessboards side by side, the number of them you would need to reach from one side of the observable universe to the other would require only 28 digits. Yet Claude Shannon, the mathematician credited as the father of the digital age, estimated that the number of unique games you could play was of the order of 10120 (a 1 followed by 120 0s). It's this level of complexity that makes chess such an attractive game and ensures that at the Olympiad in Russia in 2010, local spectators will witness games of chess never before seen by the human eye, even if the winning team turns out to have familiar names.

MANGALYAN-india's mars orbitary mission

MANGALYAN-india's mars orbitary mission:

One of the biggest accomplishment in Indian History is Mangalyaan (Mars Orbiter Mission – Mars). Indian Space Research Organization successfully launched a space probe that orbits Mars. The Mission was launched on November 5, 2013 for a 300 days journey to Mars. The fact in this mission is that India is the first in the world (Fourth after Soviet Space Program, NASa and The European Space Agency) to successfully launch the mission in the first attempt.

Mangalyaan is orbiting Mars with 5 main instruments:

• Photometer
• Methane sensor
• Instrument that analyzes Martian Exosphere
• Color Camera
• Thermal Infrared Spectrometer

An unbelievable fact about the mission is that it took only Rs. 454 crores to launch the mission. This is the cheapest Mars Mission ever (Rs. 12 per km). Any message that is sent to and fro takes 14 minutes to reach the receiver. The major objective of the mission is to prove India’s spacecraft building and operations capabilities to the world. The project aims at developing technologies of an Interplanetary Mission.

The secondary objective of the mission is to learn surface of Mars and its mineral composition  (to study Mineralogy and Morphology). The mission also aims to scan the atmosphere of Mars to availability of Methane which is a chemical strongly tied to life on Earth. Scientists are also determining the quantities of water in Martian atmosphere so as to learn the history of the Red Planet, Mars.

The success of Mangalyaan is a great achievement in the history of India and has strengthened the position of India in Space Science. The mission is a great motivation for budding scientists and gives ways for more successful mission from our country in future.  ISRO has planned a follow up Mission – Mangalyaan 2 which is likely to happen between 2018 and 2020 and it would consist of a Lander and a Mars Rover.

THERMAL POWER PLANT

THERMAL POWER PLANT:

Thermal energy is obtained by burning of fuel. Thermal electric stations make use of turbines driven by steam. Steam for power plants is often obtained by burning brown or bituminous coal or oil or natural gas. Heat may also be generated by nuclear fission.

Thermal power plants are more useful than hydro-electric plants. The following are some of the edges of a thermal plant over hydro-electric plant:

(a)Low Costs.

The initial capital requirement for a thermal plant is about 50% of that of hydro-electric plant. Thermal electricity is quite important in total electricity production in India. Thermal power states are generally located near the coal deposits.

(b)Less time in Construction.

There is no need to spend time on surveying the area for installation of a thermal power plant. But for the construction of hydro­electric plant geological survey etc. and laboratory tests take considerable time. Therefore, Thermal plants take less time in construction.

(c) Use of Inferior Coal.

A large quantities of small and broken inferior grade coal can be effectively utilized for producing thermal electricity. However, the disadvantages of thermal electricity are low efficiency in terms of heating value and higher operating cost than a hydro-electric plant.

Thermal electricity is quite important in total electricity production in India. Thermal power states are generally located near the coal deposits.

In India, the states of Bihar, Delhi, Haryana, Punjab, West Bengal and Gujarat are the main producers of thermal-power.

world biggest tree-sequoia

world biggest tree-sequoia:

sequoia

The largest tree in the world is a giant sequoia (Sequoiadendrongiganteum) in California's Sequoia National Park. Called General Sherman, the tree is about 52,500 cubic feet (1,487 cubic meters) in volume

General Sherman is a giant sequoia (Sequoiadendron giganteum) tree located in the Giant Forest of Sequoia National Park in Tulare County, in the U.S. state of California. By volume, it is the largest known living single stem tree on Earth.

With its relatively slender silhouette this tree can grow even up to 20 m or 60 ft taller than the tallest giant sequoias, that are nevertheless the biggest trees in the world, when looking at the volume of the trunk. The tallest known living tree, named Hyperion, is 115.55 m or 379.1 ft (measured in 2006) tall!

SOLAR POWER PLANT

SOLAR POWER PLANT:

The heat of the sun is about equivalent to burning a billion trillion tons of coal an hour. Even though only a small fraction of that heat ever reaches the earth it is still more then enough to power the whole world.

People seemed to realize the importance of the sun around 30,000 BC. This was when people first started planting crops of wheat. They realized plants did better when planted in the sun over the shade. This caused them to worship the sun as a God. Many cultures built large and extravagant temples to worship the sun in. Other cultures built places to observe the sun in, such as Stonehenge in England.

Different Types of Solar Panels
There are three main types of solar panels. They are flat plate collectors, focusing collectors, and solar cells.
The first kind is a flat plate collector. Flat plate collectors are fastened on the top of the roof of a house. They usually either heat the house or its water. A flat plate collector consists of a black rectangular frame, two or three sheets of glass, and copper plumbing. A flat plat collector uses the greenhouse affect. The sunrays go through the glass but can’t get out through the glass. The sunrays heat the water-filled copper tubes. Then the water is used to heat the home or water.

Another type of a solar panel is a focusing collector. They consist of a mirror or mirrors which are focused in one spot. Some focusing collectors are solar furnaces, parabolic dishes and troughs and power towers.

The first type is a solar furnace. A solar furnace consists of many mirrors that are aimed at a large curved mirror that is aimed at a large steel building. This building can get as hot as 5,790 F. Scientists use solar furnaces to run experiments to see how certain materials react to extreme heats. They are also used industrially to melt metals.

The next kind of focusing collector is a parabolic trough and dish. A parabolic dish looks just like a satellite dish except the dish part is to reflect the sunrays onto the vocal point which is filled with oil. The heated oil is used to produce steam to turn a turbine. A parabolic trough uses the same principles as a parabolic dish. The only differences are how they look, the mirror is shaped like a large feeding trough and the vocal point is an oil filled tube. These are used for either commercial such as in a power plant.

The last focusing collector is a power tower. A power tower has many mirrors all focused on a large tower. This tower gets extremely hot. The tower is filled with oil. When the oil is heated it is piped to a power plant where it is used to produce steam that turns a turbine. These are used for power plants.

The final type of solar panel is a solar cell. A solar cell usually consists of two layers of silicon that produce an electric charge which is picked up by wires that are laid across the silicon. Solar cells can be used for anything from powering an isolated phone booth to a whole city or even an airplane.

History
Solar Energy started around 30,000 BC when people first desalinized water, or took the salt out of salt water. In 1,000 BC a king had the water in his castle heated by the sun. Romans passively heated their homes in about 100 AD. In a passive solar home there is no machinery, but there are windows and the floors and windows are made of materials that absorbs heat, like adobe.
Solar heating was not used until the late sixteenth century when European scientists started experimenting with the power of the sun. In 1714 many people worked together to create the world’s first solar furnace. In 1720 a Swiss scientist, Horace Benedict de Sasure, built the first modern solar water heater. In 1774 Antoine Lavoiser made a printing press powered by the sun. Later in 1880 in Chile a solar desalinization system was made. Also in 1880 the first solar cells were made. Solar cells when originally made they were very expensive and were not available on the market. Now you can buy solar cells cheaply.

Current Applications
Today we use solar power to do many things. We use solar power for everything from calculators to large power plants that can power large cities.

Most common solar power is used for small things. Many calculators are run by solar cells so they will never run out of batteries. Some watches run on solar cells, too. Also you can buy radios that run on solar cells.
There are also many big things that run on solar power. Almost all satellites run on solar power, because otherwise they would run out of power. There are also large desalinization plants that use solar power in places where there is little or no fresh water. There are solar furnaces in many countries. Solar power is also used commercially and residentially. It is also used for many forms of transportation, but these are all in the experimental stage now. Solar powered cars may soon come out.

Indirect Solar Power
There are three forms of indirect solar power. They are wind power, waterpower, and ocean thermal energy. You might think these have nothing to do with each other or solar power but they do, in some way they each use the sun.

The first type is wind power. The reason this is a form of solar energy is because the sun heats the air that creates air currents, or wind. The wind turns propellers that turn turbines which creates electricity. Wind power has been used for a very long time. Places in Europe like the Netherlands have had windmills since the Middle Ages. Though these windmills were used to pump water or to grind grain.

The next form is waterpower. This is considered solar power because of the hydrologic cycle. The hydrologic cycle is water evaporating from bodies of water then coming back to earth in different places. This allows them to go back through dams to produce electricity. The water turns turbines, which then create electricity. Waterpower is also an old process it used to be used at sawmills and to grind down grain.

The last kind of indirect solar power is ocean thermal energy. Ocean thermal energy is a power plant that uses the difference between the surface temperature and the temperature of the bottom of the ocean to produce electricity. When the cool water meets the hot water it produces steam that turns a turbine to produce electricity. The electricity is then sent to land through wires. This is solar power because the sun heats it.

The Solar Future
Today the use of solar power is very limited. Today we use very little active solar heating. Though in the future many more homes will be solar heated. More homes will have passive solar heating. Scientists want to make a satellite that will orbit over one place. This satellite would have giant wings made of solar power, this satellite would beam electricity down to earth. This would allow the solar cells not to be obstructed by clouds or buildings. Also ground solar power plants are predicted to be used more frequently. Another thing predicted to be popular is solar powered cars. The drawback of these cars is the fact that you can only travel at high speeds for a short time and they don’t work on cloudy days. Solar powered cars are only used for racing and experiments now.

I think if there is another oil crisis there will be much more use of solar power. Solar power will be given more federal funding which will increase studies. The increased studies will make solar power cheaper and more efficient. This will make solar power more available on the market.

CONCLUSION
I think that solar power is a good alternative energy source. It has many advantages over fossil fuels. One is that the sun is free and does not have to be bought like other fuels. It also doesn’t hurt the environment and it is a renewable energy source. There are a few drawbacks to solar power. One is that it can be expensive to make and can be hard to use on cloudy days. Solar power is also difficult and expensive to store. Another bad thing is that silicon the material that solar cells are made of can be hard to find.

If there is another energy crisis like the United States experienced in the 1970’s, solar power will be greatly increased. Federal funding will be increased to promote the studies of solar power. This will make solar power more efficient which will cause it to become cheaper.

After the last energy crisis, most federal funding was decreased or stopped. This is very unfortunate because solar power would be far more advanced with more funding.

EXPERIMENT
Hypothesis: I think that some of the water will get into the inner bowl, this water will be fresh and the salt will still be in the outer bowl. I think that it will work better on sunny days than on cloudy days.
Procedure: First I mixed two cups of water with two tablespoons of salt. I put the salt water into a large aluminum bowl. Then I put a small cereal bowl into the large bowl. I covered the large bowl with plastic wrap to keep the water from evaporating out of the bowl. After the bowl was covered I put a weight on the plastic wrap so the water would drip into the cereal bowl after it evaporated. I started this experiment at seven o’clock and then took observations at three and eight; I took all three observations for five days.

Observations: On the first day at three there was some water on the plastic wrap after it had evaporated. At eight most of the water on the plastic wrap had dripped into the inner bowl. That day it was sunny. At seven the next there was a little more water in the small bowl. At three that day there was a little on the plastic wrap. At eight the little water on the plastic water had gone into the cereal bowl. It was cloudy that day. In the morning at seven there was no change from the night. At three that day there was a little water on the plastic wrap. At eight most of the water on the plastic wrap was in the cereal bowl. On the fourth day at seven the rest of the water was in the cereal bowl. At three the rest of there was a little on the plastic wrap. That night at eight the rest of the water on the plastic wrap was in the cereal bowl. It was partly cloudy that day. On the last day in the morning there was no change from the night before. At three there was a little more water on the plastic wrap. The water on the plastic wrap was in the small bowl. It was partly cloudy that day.
Conclusion: My hypothesis was correct, but I thought more water would be purified then actual did get purified. The water in the cereal bowl had no salt in it. This experiment proves that solar power works and that it works better with no clouds than with clouds.

engine-UNKNOWN FACTS

engine-UNKNOWN FACTS:

Internal Combustion Engine, a heat engine in which the fuel is burned ( that is, united with oxygen ) within the confining space of the engine itself. This burning process releases large amounts of energy, which are transformed into work through the mechanism of the engine. This type of engine different from the steam engine, which process with an external combustion engine that fuel burned apart from the engine. The principal types of internal combustion engine are : reciprocating engine such as Otto-engine, and Diesel engines ; and rotary engines, such as the Wankel engine and the Gas-turbine engine.

In general, the internal combustion engine has become the means of propulsion in the transportation field, with the exception of large ships requiring over 4,000 shaft horsepower ( hp).

In stationary applications, size of unit and local factor often determine the choice between the use of steam and diesel engine. Diesel power plants have a distinct economic advantage over steam engine when size of the plant is under about 1,000 hp. However there are many diesel engine plants much large than this. Internal combustion engines are particularly appropriate for seasonal industries, because of the small standby losses with these engines during the shutdown period.

History

The first experimental internal combustion engine was made by a Dutch astronomer, Christian Huygens, who, in 1680, applied a principle advanced by Jean de Hautefeuille in 1678 for drawing water. This principle was based on the fact that the explosion of a small amount of gunpowder in a closed chamber provided with escape valves would create a vacuum when the gases of combustion cooled. Huygens, using a cylinder containing a piston, was able to move it in this manner by the external atmospheric pressure.

The first commercially practical internal combustion engine was built by a French engineer, ( Jean Joseph ) Etienne Lenoir, about 1859-1860. It used illuminating gas as fuel. Two years later, Alphonse Beau de Rochas enunciated the principles of the four-stroke cycle, but Nickolaus August Otto built the first successful engine ( 1876 ) operating on this principle.

Reciprocating Engine

Components of Engines

The essential parts of Otto-cycle and diesel engines are the same. The combustion chamber consists of a cylinder, usually fixed, which is closed at one end and in which a close-fitting piston slides. The in-and-out motion of the piston varies the volume of the chamber between the inner face of the piston and the closed end of the cylinder. The outer face of the piston is attached to a crankshaft by a connecting rod. The crankshaft transforms the reciprocating motion of the piston into rotary motion. In multi-cylindered engines the crankshaft has one offset portion, called a crankpin, for each connecting rod, so that the power from each cylinder is applied to the crankshaft at the appropriate point in its rotation. Crankshafts have heavy flywheels and counterweights, which by their inertia minimize irregularity in the motion of the shaft. An engine may have from 1 to as many as 28 cylinders.

Fig. 1, Component of Piston Engines.

The fuel supply system of an internal-combustion engine consists of a tank, a fuel pump, and a device for vaporizing or atomizing the liquid fuel. In Otto-cycle engines this device is a carburetor. The vaporized fuel in most multi-cylindered engines is conveyed to the cylinders through a branched pipe called the intake manifold and, in many engines, a similar exhaust manifold is provided to carry off the gases produced by combustion. The fuel is admitted to each cylinder and the waste gases exhausted through mechanically operated poppet valves or sleeve valves. The valves are normally held closed by the pressure of springs and are opened at the proper time during the operating cycle by cams on a rotating camshaft that is geared to the crankshaft . By the 1980s more sophisticated fuel-injection systems, also used in diesel engines, had largely replaced this traditional method of supplying the proper mix of air and fuel; computer-controlled monitoring systems improved fuel economy and reduced pollution.

Ignition

In all engines some means of igniting the fuel in the cylinder must be provided. For example, the ignition system of Otto-cycle engines , the mixture of air and gasoline vapor delivered to the cylinder from the carburetor and next operation is that of igniting the charge by causing a spark to jump the gap between the electrodes of a spark plug, which projects through the walls of the cylinder. One electrode is insulated by porcelain or mica; the other is grounded through the metal of the plug, and both form the part of the secondary circuit of an induction system.

The principal type of high-tension ignition now commonly used is the battery-and-coil system. The current from the battery flows through the low-tension coil and magnetizes the iron core. When this circuit is opened at the distributor points by the interrupter cam, a transient high-frequency current is produced in the primary coil with the assistance of the condenser. This induces a transient, high-frequency, high-voltage current in the secondary winding. This secondary high voltage is needed to cause the spark to jump the gap in the spark plug. The spark is directed to the proper cylinder to be fired by the distributor, which connects the secondary coil to the spark plugs in the several cylinders in their proper firing sequence. The interrupter cam and distributor are driven from the same shaft, the number of breaking points on the interrupter cam being the same as the number of cylinders.

Cooling System

Because of the heat of combustion, all engines must be equipped with some type of cooling system. Some aircraft and automobile engines, small stationary engines, and outboard motors for boats are cooled by air. In this system the outside surfaces of the cylinder are shaped in a series of radiating fins with a large area of metal to radiate heat from the cylinder. Other engines are water-cooled and have their cylinders enclosed in an external water jacket. In automobiles, water is circulated through the jacket by means of a water pump and cooled by passing through the finned coils of a radiator. Some automobile engines are also air-cooled, and in marine engines sea water is used for cooling.

Starter

Unlike steam engines and turbines, internal-combustion engines develop no torque when starting, and therefore provision must be made for turning the crankshaft so that the cycle of operation can begin. Automobile engines are normally started by means of an electric motor or starter that is geared to the crankshaft with a clutch that automatically disengages the motor after the engine has started. Small engines are sometimes started manually by turning the crankshaft with a crank or by pulling a rope wound several times around the flywheel. Methods of starting large engines include the inertia starter, which consists of a flywheel that is rotated by hand or by means of an electric motor until its kinetic energy is sufficient to turn the crankshaft, and the explosive starter, which employs the explosion of a blank cartridge to drive a

turbine wheel that is coupled to the engine. The inertia and explosive starters are chiefly used to start airplane engines.

Otto-Cycle Engines

The ordinary Otto-cycle engine is a four-stroke engine; that is, its pistons make four strokes, two toward the head (closed head) of the cylinder and two away from the head, in a complete power cycle. During the first stroke of the cycle, the piston moves away from the cylinder head while simultaneously the intake valve is opened. The motion of the piston during this stroke sucks a quantity of a fuel and air mixture into the combustion chamber. During the next stroke the piston moves toward the cylinder head and compresses the fuel mixture in the combustion chamber. At the moment when the piston reaches the end of this stroke and the volume of the combustion chamber is at a minimum, the fuel mixture is ignited by the spark plug and burns, expanding and exerting a

pressure on the piston, which is then driven away from the cylinder head in the third stroke. At the end of the power stroke the pressure of the burned gases in the cylinder is 2.8 to 3.5 kg/sq. cm (40 to 50 lb./sq. in). During the final stroke, the exhaust valve is opened and the piston moves toward the cylinder head, driving the exhaust gases out of the combustion chamber and leaving the cylinder ready to repeat the cycle.

Fig. 2, Otto-Cycle Engines.

The efficiency of a modern Otto-cycle engine is limited by a number of factors, including losses by cooling and by friction. In general the efficiency of such engines is determined by the compression ratio of the engine. The compression ratio (the ratio between the maximum and minimum volumes of the combustion chamber) is usually about 8 to 1 or 10 to 1 in most modern Otto-cycle engines. Higher compression ratios, up to about 12 to 1, with a resulting increase of efficiency, are possible with the use of high-octane antiknock fuels. The efficiencies of good modern Otto-cycle engines range between 20 and 25 percent (in other words, only this percentage of the heat energy of the fuel is transformed into mechanical energy).

Diesel Engines

Theoretically the diesel cycle differs from the Otto cycle in that combustion takes place at constant volume rather than at constant pressure. Most diesels are also four-stroke engines, but operate differently than the four-stroke Otto-cycle engines. The first or suction stroke draws air, but no fuel, into the combustion chamber through an intake valve. On the second or compression stroke the air is compressed to a small fraction of its former volume and is heated to approximately 440° C (approximately 820° F) by this compression. At the end of the compression stroke vaporized fuel is injected into the combustion chamber

Fig. 3, Four-Stroke Diesel Engines.

and burns instantly because of the high temperature of the air in the chamber. Some diesels have auxiliary electrical ignition systems to ignite the fuel when the engine starts, and until it warms up. This combustion drives the piston back on the third or power stroke of the cycle. The fourth stroke, as in the Otto-cycle engine, is an exhaust stroke.

The efficiency of the diesel engine, which is in general governed by the same factors that control the efficiency of Otto-cycle engines, is inherently greater than that of any Otto-cycle engine and in actual engines today is slightly over 40 percent. Diesels are in general slow-speed engines with crankshaft speeds of 100 to 750 revolutions per minute (rpm) as compared to 2500 to 5000 rpm for typical Otto-cycle engines. Some types of diesel, however, have speeds up to 2000 rpm. Because diesels use compression ratios of 14 or more to 1, they are generally more heavily built than Otto-cycle engines, but this disadvantage is counterbalanced by their greater efficiency and the fact that they can be operated on less expensive fuel oils.

Two-Stroke Engines

By suitable design it is possible to operate an Otto-cycle or diesel as a two-stroke or two-cycle engine with a power stroke every other stroke of the piston instead of once every four strokes. The efficiency of such engines is less than that of four-stroke engines, and therefore the power of a two-stroke engine is always less then half that of a four-stroke engine of comparable size.

The general principle of the two-stroke engine is to shorten the periods in which fuel is introduced to the combustion chamber and in which the spent gases are exhausted to a small fraction of the duration of a stroke instead of allowing each of these operations to occupy a full stroke. In the simplest type of two-stroke engine, the poppet valves are replaced by sleeve valves or ports (openings in the cylinder wall that are uncovered by the piston at the end of its outward travel). In the two-stroke cycle the fuel mixture or air is introduced through the intake port when the piston is fully withdrawn from the cylinder. The compression stroke follows and the charge is ignited when the piston reaches the end of this stroke. The piston then moves outward on the power stroke, uncovering the exhaust port and permitting the gases to escape from the combustion chamber.

Fig. 4, Two-Stroke Engines.

Rotary Engine

Wankel Engines

Fig. 5 The Wankel Engine

In the 1950s the German engineer Felix Wankel developed his concept of an internal-combustion engine of a radically new design, in which the piston and cylinder were replaced by a three-cornered rotor turning in a roughly oval chamber. The fuel-air mixture is drawn in through an intake port and trapped between one face of the turning rotor and the wall of the oval chamber. The turning of the rotor compresses the mixture, which is ignited by a spark plug. The exhaust gases are then expelled through an exhaust port through the action of the turning rotor. The cycle takes place alternately at each face of the rotor, giving three power strokes for each turn of the rotor. The Wankel engine's compact size and consequent lesser weight as compared with the piston engine gave it increasing value and importance with the rise in gasoline prices of the 1970s and '80s. In addition, it offers practically vibration-free operation, and its mechanical simplicity provides low manufacturing costs. Cooling requirements are low, and its low center of gravity contributes to driving safety.

Gas Turbine

Also called as combustion turbine, engine that employs gas flow as the working medium by which heat energy is transformed into mechanical energy. Gas is produced in the engine by the combustion of certain fuels. Stationary nozzles discharge jets of this gas against the blades of a turbine wheel. The impulse force of the jets causes the shaft to turn. A simple-cycle gas turbine includes a compressor that pumps compressed air into a combustion chamber. Fuel in gaseous or liquid-spray form is also injected into this chamber, and combustion takes place there. The combustion products pass from the chamber through the nozzles to the turbine wheel. The spinning wheel drives the compressor and the external load, such as an electrical generator.

In a turbine or compressor, a row of fixed blades and a corresponding row of moving blades attached to a rotor is called a stage. Large machines employ multistage axial-flow compressors and turbines. In multi-shaft arrangements, the initial turbine stage (or stages) powers the compressor on one shaft while the later turbine stage (or stages) powers the external load on a separate shaft.

The efficiency of the gas-turbine cycle is limited by the need for continuous operation at high temperatures in the combustion chamber and early turbine stages. A small, simple-cycle gas turbine may have a relatively low thermodynamic efficiency, comparable to a conventional gasoline engine. Advances in heat-resistant materials, protective coatings, and cooling arrangements have made possible large units with simple-cycle efficiencies of 34 percent or higher.

The efficiency of gas-turbine cycles can be enhanced by the use of auxiliary equipment such as inter-coolers, regenerators, and reheaters. These devices are expensive, however, and economic considerations usually preclude their use.

In a combined-cycle power plant, the considerable heat remaining in the gas turbine exhaust is directed to a boiler called a heat-recovery steam generator. The heat so recovered is used to raise steam for an associated steam turbine. The combined output is approximately 50 percent greater than that of the gas turbine alone. Combined cycles with thermal efficiency of 52 percent and higher are being put into service. Gas turbines have been applied to the propulsion of ships and railroad locomotives. A modified form of gas turbine, the turbojet, is used for airplane propulsion. Heavy-duty gas turbines in both simple and combined cycles have become important for large-scale generation of electricity. Unit ratings in excess of 200 megawatts (MW) are available. The combined-cycle output can exceed 300 MW.

The usual fuels used in gas turbines are natural gas and liquids such as kerosene and diesel oil. Coal can be used after conversion to gas in a separate gasifier.

Internal-Combustion Engines and Air Pollution

Air pollution from automobile engines ( smog ) was first detected about 1942 in Los Angeles, CA. Smog arises from sunlight-induced photochemical reactions between nitrogen dioxide and the several hundred hydrocarbons in the atmosphere. Undesirable products of the reactions include ozone, aldehydes, and peroxyacylnitrates ( PAN ). These are highly oxidizing in nature and cause eye and throat irritation. Visibility-decreasing nitrogen dioxide and aerosols are also formed.

Five categories of air pollutants and percent contribution from all transportation source and the highway vehicle subset are show in Table -1. Virtually all of the transportation CO, about half the hydrocarbons, and about one-third of the nitrogen oxides come from gasoline engines. Diesel engines account for the particulate.

Table-1. Estimated Total Annual US Emissions from Artificial Sources (1980)

Carbonmonoxide HydrocarbonsSulfuroxidesNitrogenoxides Particulate

Total, teragram/yr. 85.4 21.8 23.7 20.7 7.8

All transportation, % 81 36 3.8 44 18

Highway vehicles, % 72 29 1.7 32 14

SOURCE: EPA Report 450/4-82-001, 1982.

Emissions from internal-combustion engines include those from blowby, evaporation, and exhaust. These can vary considerably in amount and composition depending on engine type, design, and condition, fuel-system type, fuel volatility, and engine operating point. For an automobile without emission control it is estimated that of the hydrocarbon emission, 20 to 25 percent arise from blowby, 60 percent from the exhaust, and the balance from evaporative losses primarily from the fuel tank and to a lesser extent from the carburetor. All other non-hydrocarbon emissions emanate from the exhaust.

At least 200 hydrocarbon (HC) compounds have been identified in exhaust. Some such as the olefin compounds react products. These are termed reactive hydrocarbons. Others such as the paraffin are virtually unreactive.

Special Developments

The Stratified-Charge Engine a modification of the conventional spark-ignition piston engine, the stratified charge engine is designed to reduce emissions without the need for an exhaust-gas recirculation system or catalytic converter. Its key feature is a dual combustion chamber for each cylinder, with a prechamber that receives a rich fuel-air mixture while the main chamber is charged with a very lean mixture. The spark ignites the rich mixture that in turn ignites the lean main mixture. The resulting peak temperature is low enough to inhibit the formation of nitrogen oxides, and the mean temperature is sufficiently high to limit emissions of carbon monoxide and hydrocarbon.

Two rather distinct means for accomplishing the stratified charge condition are under consideration :

1. A single combustion chamber with a well-controlled rotating air motion. This arrangement is illustrated (Fig.6) by the Texaco Combustion Process (TCP), patented in 1949.

2. A prechamber or two-chamber system. This is illustrated by Fig.7, which shows the general arrangement of the Honda Compound-vortex controlled-combustion (CVCC) system.

For both systems, very careful development has proved to be necessary to obtain complete combustion of the fuel under the wide range of speed and load conditions required of an automotive engine.

Fig. 6, Texaco Combustion process (TCP).

Fig. 7, Honda CVCC combustion process.