Wormhole

A hypothetical "tunnel" connecting two different points in spacetime in such a way that a trip through the wormhole could take much less time than a journey between the same starting and ending points in normal space. The ends of a wormhole could, in theory, be intra-universe (i.e. both exist in the same universe) or inter-universe (exist in different universes, and thus serve as a connecting passage between the two).

Wormholes arise as solutions to the equations of Einstein's general theory of relativity. In fact, they crop up so readily in this context that some theorists are encouraged to think that real counterparts may eventually be found or fabricated and, perhaps, used for high-speed space travel and/or time travel. However, a known property of wormholes is that they are highly unstable and would probably collapse instantly if even the tiniest amount of matter, such as a single photon, attempted to pass through them. A possible way around this problem is the use of exotic matter to prevent the wormhole from pinching off.

A brief history of wormholes

The theory of wormholes goes back to 1916, shortly after Einstein published his general theory, when Ludwig Flamm, an obscure Austrian physicist, looked at the simplest possible solution of Einstein's field equations, known as the Schwarzschild solution (or Schwarzschild metric). This describes the gravitational field around a spherically-symmetric non-rotating mass. If the mass is sufficiently compact, the solution describes a particular form of the phenomenon now called a black hole – the Schwarzschild black hole. Flamm realized that Einstein's equations allowed a second solution, now known as a white hole, and that the two solutions, describing two different regions of (flat) spacetime were connected (mathematically) by a spacetime conduit.¹ Because the theory has nothing to say about where these regions of spacetime might be in the real world, the black hole "entrance" and white hole "exit" could be in different parts of the same universe or in entirely different universes.

In 1935, Einstein and Nathan Rosen further explored, it can be appreciated with hindsight, the theory of intra- or inter-universe connections in a paper² whose actual purpose was to try to explain fundamental particles, such as electrons, in terms of spacetime tunnels threaded by electric lines of force. Their work gave rise to the formal name Einstein-Rosen bridge for what the physicist John Wheeler would later call a "wormhole." (Wheeler also coined the terms "black hole" and "quantum foam".) Wheeler's 1955 paper³ discusses wormholes in terms of topological entities called geons and, incidentally, provides the first (now familiar) diagram of a wormhole as a tunnel connecting two openings in different regions of spacetime.

Traversable wormholes

Interest in so-called traversable wormholes gathered pace following the publication of a 1987 paper by Michael Morris, Kip Thorne, and Uri Yertsever (MTY) at the California Institute of Technology.^{4, 5} This paper stemmed from an inquiry to Thorne by Carl Sagan who was mulling over a way of conveying the heroine in his novel Contact across interstellar distances at trans-light speed. Thorne gave the problem to his Ph.D. students, Michael Morris and Uri Yertsever, who realized that such a journey might be possible if a wormhole could be held open long enough for a spacecraft (or any other object) to pass through. MTY concluded that to keep a wormhole open would require matter with a negative energy density and a large negative pressure – larger in magnitude than the energy density. Such hypothetical matter is called exotic matter.

Although the existence of exotic matter is speculative, a way is known of producing negative energy density: the Casimir effect. As a source for their wormhole, MTY turned to the quantum vacuum. "Empty space" at the smallest scale, it turns out, is not empty at all but seething with violent fluctuations in the very geometry of spacetime. At this level of nature, ultra-small wormholes are believed to continuously wink into and out of existence. MTY suggested that a sufficiently advanced civilization could expand one of these tiny wormholes to macroscopic size by adding energy. Then the wormhole could be stabilized using the Casimir effect by placing two charged superconducting spheres in the wormhole mouths. Finally, the mouths could be transported to widely-separated regions of space to provide a means of FTL communication and travel. For example, a mouth placed aboard a spaceship might be carried to some location many light-years away. Because this initial trip would be through normal spacetime, it would have to take place at sublight speeds. But during the trip and afterwards instantaneous communication and transport through the wormhole would be possible. The ship could even be supplied with fuel and provisions through the mouth it was carrying. Also, thanks to relativistic time-dilation, the journey need not take long, even as measured by Earth-based observers. For example, if a fast starship carrying a wormhole mouth were to travel to Vega, 25 light-years away, at 99.995% of the speed of light (giving a time-dilation factor of 100), shipboard clocks would measure the journey as taking just three months. But the wormhole stretching from the ship to Earth directly links the space and time between both mouths – the one on the ship and the one left behind on (or near) Earth. Therefore, as measured by Earthbound clocks too, the trip would have taken only three months – three months to establish a more-or-less instantaneous transport and communications link between here and Vega.

Star Trek's Deep Space 9 is located alongside a natural wormhole that leads to the other side of the Galaxy

Of course, the MTY scheme is not without technical difficulties, one of which is that the incredibly powerful forces needed to hold the wormhole mouths open might tear apart anything or anyone that tried to pass through. In an effort to design a more benign environment for travelers using a wormhole, Matt Visser of Washington University in St. Louis conceived an arrangement in which the spacetime region of a wormhole mouth is flat (and thus force-free) but framed by struts of exotic matter that contain a region of very sharp curvature.⁶ Visser envisages a cubic design, with flat-space wormhole connections on the square sides and cosmic strings as the edges. Each cube-face may connect to the face of another wormhole-mouth cube, or the six cube faces may connect to six different cube faces in six separated locations.

In 2011, Panagiota Kanti (University of Ioannina) and Burkhard Kleihaus (Universität Oldenburg) showed how it might be possible to construct traversable wormholes without using exotic matter by resorting to a form of string theory.¹⁰

Given that our technology is not yet up to the task of building a wormhole subway, the question arises of whether they might already exist. One possibility is that advanced races elsewhere in the Galaxy or beyond have already set up a network of wormholes that we could learn to use. Another is that wormholes might occur naturally. David Hochberg and Thomas Kephart of Vandebilt University have discovered that, in the earliest moments of the Universe, gravity itself may have given rise to regions of negative energy in which natural, self-stabilizing wormholes may have formed. Such wormholes, created in the Big Bang, might be around today, spanning small or vast distances in space.

References

1. Flamm, L. "Comments on Einstein's theory of gravity," Physikalische Zeitschrift, 17, 48 (1916).
2. Einstein, A., and Rosen, N. "The Particle Problem in the General Theory of Relativity", Physical Review, 48, 73 (1935)
3. Wheeler, J. A. "Geons," Physical Review, 97, 511–536 (1955).
4. Morris, M. S, Thorne, K. S., and Yurtsever, U. "Wormholes, time machines, and the weak energy condition," Phys. Rev. Letters, 61, 1446–1449 (1988).
5. Morris, M. S., and Thorne, K. S. "Wormholes in spacetime and their use for interstellar travel: A tool for teaching general relativity", Am. J. Phys., 56, No. 5, 395–412 (1988).
6. Visser, M. "Wormholes, baby universes, and causality", Phys. Rev. D, 41, No. 4, 1116–1124 (1990).
7. Hochberg, D. and Visser, M. "Geometric structure of the generic static traversable wormhole throat", Phys. Rev. D, Phys. Rev D56, 4745 (1997).
8. Maccone, C. "Interstellar travel through magnetic wormholes", Journal of the British Interplanetary Society, 48, No. 11, 453–458 (1995).
9. Visser, M. (1995) Lorentzian Wormholes – From Einstein to Hawking, Woodbury, NY: AIP Press (1995).
10. Kantio, P. and Kleihaus, B., "Wormholes in dilatonic Einstein-Gauss-Bonnet theory." arXiv (2011).

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Newton's three law of motion: Animated

According to Newton's first law...

An object at rest will remain at rest unless acted on by an unbalanced force.An object in motion continues in motion with the same speed and in the same direction unless acted upon by an unbalanced force.This law is often called "the law of inertia".

What does this mean?This means that there is a natural tendency of objects to keep on doing what they're doing. All objects resist changes in their state of motion. In the absence of an unbalanced force, an object in motion will maintain this state of motion.

Let's study the "skater" to understand this a little better.
What is the motion in this picture?

What is the unbalanced force in this picture?

What happened to the skater in this picture?



This law is the same reason why you should always wear your seatbelt.




Now that you understand
Newton's First Law of Motion,
let's go on to his Second Law of Motion.    

According to Newton's second law...

Acceleration is produced when a force acts on a mass. The greater the mass (of the object being accelerated) the greater the amount of force needed (to accelerate the object).

What does this mean?Everyone unconsiously knows the Second Law. Everyone knows that heavier objects require more force to move the same distance as lighter objects.



However, the Second Law gives us an exact relationship between force,mass, and acceleration. It can be expressed as a mathematical equation:

or
FORCE = MASS times ACCELERATION



This is an example of how Newton's Second Law works:
Mike's car, which weighs 1,000 kg, is out of gas. Mike is trying to push the car to a gas station, and he makes the car go 0.05 m/s/s. Using Newton's Second Law, you can compute how much force Mike is applying to the car.


Answer = 50 newtons


This is easy, let's go on to
Newton's Third Law of Motion

  

According to Newton's third law...

For every action there is an equal and opposite re-action.

What does this mean?

This means that for every force there is a reaction force that is equal in size, but opposite in direction. That is to say that whenever an object pushes another object it gets pushed back in the opposite direction equally hard.



Let's study how a rocket works to understand
Newton's Third Law.

The rocket's action is to push down on the ground with the force of its powerful engines,and the reaction is that the ground pushes the rocket upwards with an equal force.

UP, UP, and AWAY!

You have just learned about
Newton's Three Laws of Motion.

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Newton's Three Laws of Motion

For Animated version See Newton's three law of motion: Animated



Let us begin our explanation of how Newton changed our understanding of the Universe by enumerating his Three Lawsof Motion.

Newton's First Law of Motion:

I. Every object in a state of uniform motion tends to remain in thatstate of motion unless an external force is applied to it.

This we recognize as essentially Galileo's concept of inertia, and this is oftentermed simply the "Law of Inertia".

Newton's Second Law of Motion:

II. The relationship between an object's mass m, its accelerationa, and the applied force F isF = ma.Acceleration and force are vectors (as indicated by their symbols beingdisplayed in slant bold font); in this law the direction of the forcevector is the same as the direction of the acceleration vector.

This is the most powerful of Newton's three Laws, because it allows quantitativecalculations of dynamics: how do velocities change when forces are applied.Notice the fundamental difference between Newton's 2nd Law and the dynamics ofAristotle: according to Newton, a force causes only a change invelocity (an acceleration); it does not maintain the velocity as Aristotleheld.
This is sometimes summarized by saying that under Newton, F =ma, but under Aristotle F = mv, where v is the velocity.Thus, according to Aristotle there is only a velocity if there is a force, butaccording to Newton an object with a certain velocity maintains thatvelocity unless a force acts on it to cause an acceleration (that is,a change in the velocity). As we have noted earlier in conjunction with thediscussion of Galileo, Aristotle's view seems to bemore in accord with common sense, but that is because of a failure toappreciate the role played by frictional forces. Once account is taken of all forcesacting in a given situation it is the dynamics of Galileo and Newton, not of Aristotle, that arefound to be in accord with the observations.

Newton's Third Law of Motion:

III. For every action there is an equal and opposite reaction.

This law is exemplified by what happens if we step off a boat onto the bank ofa lake: as we move in the direction of the shore, the boat tends to move inthe opposite direction (leaving us facedown in the water, if we aren'tcareful!).

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Dipolar Bonding in Water

The dipolar interaction between water molecules represents a large amount of internal energy and is a factor in water's large specific heat. The dipole moment of water provides a "handle" for interaction with microwave electric fields in a microwave oven. Microwaves can add energy to the water molecules, whereas molecules with no dipole moment would be unaffected.

The polar nature of water molecules allows them to bond to each other in groups and is associated with the high surface tension of water. The polar nature of the water molecule has many implications. It causes water vapor at sufficient vapor pressure to depart from the ideal gas law because of dipole-dipole attractions. This can lead to condensation and phenomena like cloud formation, fog, the dewpoint, etc. It also has a great deal to do with the function of water as the solvent of life in biological systems.

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Dipole Moment of Water

The asymmetry of the water molecule leads toa dipole moment in the symmetry plane pointed toward the more positive hydrogen atoms. The measured magnitude of this dipole moment is Treating this system like a negative charge of10 electrons and a positive charge of 10e, the effective separation of the negative and positivecharge centers is

This is 0.0039 nm compares with about .05 nm for the first Bohr radius of a hydrogen atom and about .15 nm for the effective radius of hydrogen in liquid form, so the charge separation is small compared to an atomic radius.
The polar nature of water molecules allows them to bond to each other in groups and is associated with the high surface tension of water.

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INTERNAL COMBUSTION ENGINE

The internal combustion engine is a heat engine in which the burning of a fuel occurs in a confined space called a combustion chamber. This exothermic reaction of a fuel with an oxidizer creates gases of high temperature and pressure, which are permitted to expand. The defining feature of an internal combustion engine is that useful work is performed by the expanding hot gases acting directly to cause movement, for example by acting on pistons, rotors, or even by pressing on and moving the entire engine itself.

This contrasts with external combustion engines such as steam engines which use the combustion process to heat a separate working fluid, typically water or steam, which then in turn does work, for example by pressing on a steam actuated piston.

Karl Benz

The term Internal Combustion Engine (ICE) is almost always used to refer specifically to reciprocating engines, Wankel engines and similar designs in which combustion is intermittent. However, continuous combustion engines, such as Jet engines, most rockets and many gas turbines are also very definitely internal combustion engines.

HISTORY

Non-compression

Leonardo da Vinci, in 1509, and Christiaan Huygens, in 1673, described constant pressure engines. (Leonardo's description may not imply that the idea was original with him or that it was actually constructed.)

English inventor Sir Samuel Morland used gunpowder to drive water pumps in the 17th century. In 1794, Robert Street built a compression-less engine whose principle of operation would dominate for nearly a century.

The first internal combustion engine to be applied industrially was patented by Samuel Brown in 1823. It was based on what Hardenberg calls the "Leonardo cycle," which, as this name implies, was already out of date at that time. Just as today, early major funding, in an area where standards had not yet been established, went to the best showmen sooner than to the best workers.

The Italians Eugenio Barsanti and Felice Matteucci patented the first working, efficient internal combustion engine in 1854 in London (pt. Num. 1072) but did not get into production with it. It was similar in concept to the successful Otto Langen indirect engine, but not so well worked out in detail.

In 1860, Jean Joseph Etienne Lenoir (1822 - 1900) produced a gas-fired internal combustion engine not dissimilar in appearance to a steam beam engine. This closely resembled a horizontal double acting steam engine, with cylinders, pistons, connecting-rods and fly wheel in which the gas essentially took the place of the steam. This was the first internal combustion engine to be produced in numbers.

The American Samuel Morey received a patent on April 1, 1826 for a "Gas Or Vapor Engine".

His first (1862) engine with compression having shocked itself apart, Nikolaus Otto designed an indirect acting free piston compression-less engine whose greater efficiency won the support of Langen and then most of the market, which at that time, was mostly for small stationary engines fueled by lighting gas. In 1870 in Vienna Siegfried Marcus put the first mobile gasoline engine on a handcart.

Four-stroke cycle (or Otto cycle)

Compression

The most significant distinction between modern internal combustion engines and the early designs is the use of compression and in particular of in-cylinder compression. The thermodynamic theory of idealized heat engines was established by Sadi Carnot in France in 1824. This scientifically established the need for compression to increase the difference between the upper and lower working temperatures, but it is not clear that engine designers were aware of this before compression was already commonly used. In fact it may have misled designers who attempted to emulate the Carnot cycle in ways that were not useful.

The first recorded suggestion of in-cylinder compression was a patent granted to William Barnet (English) in 1838. He apparently did not realize its advantages, but his cycle would have been a great advance if sufficiently developed.

Nikolaus Otto working with Gottlieb Daimler and Wilhelm Maybach in the 1870s developed a practical four-stroke cycle (Otto cycle) engine. The German courts, however, did not hold his patent to cover all in-cylinder compression engines or even the four stroke cycle, and after this decision in-cylinder compression became universal.

Karl Benz, working independently, was granted a patent In 1879 for his internal combustion engine, a reliable two-stroke gas engine, based on Nikolaus Otto's design of the four-stroke engine. Later Benz designed and built his own four-stroke engine that was used in his automobiles, which became the first automobiles in production.

In 1896, Karl Benz invented the boxer engine, also known as, the horizontally opposed engine, in which the corresponding pistons reach top dead centre simultaneously, thus balancing each other with respect to momentum.

Applications

Internal combustion engines are most commonly used for mobile propulsion systems. In mobile scenarios internal combustion is advantageous, since it can provide high power to weight ratios together with excellent fuel energy-density. These engines have appeared in almost all automobiles, motorbikes, many boats, and in a wide variety of aircraft and locomotives. Where very high power is required, such as jet aircraft, helicopters and large ships, they appear mostly in the form of gas turbines. They are also used for electric generators and by industry.

For low power mobile and many non-mobile applications an electric motor is a competitive alternative. In the future, electric motors may also become competitive for most mobile applications. However, the high cost, weight, and poor energy density of lead-acid batteries and even NiMH batteries and lack of affordable on board electric generators such as fuel cells has largely restricted their use to specialist applications. However recent battery advancements in lightweight Li-ion and Li-poly chemistries are bringing safety, power density, lifespan, and cost to within acceptable or even desirable levels. For example recently battery electric vehicles began to demonstrated 300 miles of range on Lithium, now improved power makes them appealing for plug-in hybrid electric vehicles whose electric range is less critical having internal combustion for unlimited range..

Internal combustion mechanics

The potato cannon uses the basic principle behind any reciprocating internal combustion engine: If you put a tiny amount of high-energy fuel (like gasoline) in a small, enclosed space and ignite it, an incredible amount of energy is released in the form of expanding gas. You can use that energy to propel a potato 500 feet. In this case, the energy is translated into potato motion. You can also use it for more interesting purposes. For example, if you can create a cycle that allows you to set off explosions like this hundreds of times per minute, and if you can harness that energy in a useful way, what you have is the core of a car engine!

Almost all cars currently use what is called a four-stroke combustion cycle to convert gasoline into motion. The four-stroke approach is also known as the Otto cycle, in honor of Nikolaus Otto, who invented it in 1867. The four strokes are illustrated in Figure 1. They are:

Intake stroke

Compression stroke

Combustion stroke

Exhaust stroke

Operation

All internal combustion engines depend on the exothermic chemical process of combustion: the reaction of a fuel, typically with air, although other oxidisers such as nitrous oxide may be employed. Also see stoichiometry.

The most common fuels in use today are made up of hydrocarbons and are derived from petroleum. These include the fuels known as diesel, gasoline and liquified petroleum gas. Most internal combustion engines designed for gasoline can run on natural gas or liquified petroleum gases without modifications except for the fuel delivery components. Liquid and gaseous biofuels, such as Ethanol can also be used. Some can run on Hydrogen, however this can be dangerous. Hydrogen burns with a colorless flame, and modifications to the cylinder block, cylinder head, and head gasket are required to seal in the flame front.

All internal combustion engines must have a means of ignition to promote combustion. Most engines use either an electrical or a compression heating ignition system. Electrical ignition systems generally rely on a lead-acid battery and an induction coil to provide a high voltage electrical spark to ignite the air-fuel mix in the engine's cylinders. This battery can be recharged during operation using an alternator driven by the engine. Compression heating ignition systems, such as diesel engines and HCCI engines, rely on the heat created in the air by compression in the engine's cylinders to ignite the fuel.

Once successfully ignited and burnt, the combustion products, hot gases, have more available energy than the original compressed fuel/air mixture (which had higher chemical energy). The available energy is manifested as high temperature and pressure which can be translated into work by the engine. In a reciprocating engine, the high pressure product gases inside the cylinders drive the engine's pistons.

Once the available energy has been removed the remaining hot gases are vented (often by opening a valve or exposing the exhaust outlet) and this allows the piston to return to its previous position (Top Dead Center - TDC). The piston can then proceed to the next phase of its cycle, which varies between engines. Any heat not translated into work is a waste product and is removed from the engine either by an air or liquid cooling system.

Illustration of several key components 

in a typical four-stroke engine

Parts

The parts of an engine vary depending on the engine's type. For a four-stroke engine, key parts of the engine include the crankshaft (purple), one or more camshafts (red and blue) and valves. For a two-stroke engine, there may simply be an exhaust outlet and fuel inlet instead of a valve system. In both types of engines, there are one or more cylinders (grey and green) and for each cylinder there is a spark plug (darker-grey), a piston (yellow) and a crank (purple). A single sweep of the cylinder by the piston in an upward or downward motion is known as a stroke and the downward stroke that occurs directly after the air-fuel mix in the cylinder is ignited is known as a power stroke.

A Wankel engine has a triangular rotor that orbits in an epitroichoidal (figure 8 shape) chamber around an eccentric shaft. The four phases of operation (intake, compression, power, exhaust) take place in separate locations, instead of one single location as in a reciprocating engine.

A Bourke Engine uses a pair of pistons integrated to a Scotch Yoke that transmits reciprocating force through a specially designed bearing assembly to turn a crank mechanism. Intake, compression, power, and exhaust all occur in each stroke of this yoke.

Classification

There is a wide range of internal combustion engines corresponding to their many varied applications. Likewise there is a wide range of ways to classify internal-combustion engines, some of which are listed below.

Although the terms sometimes cause confusion, there is no real difference between an "engine" and a "motor." At one time, the word "engine" (from Latin, via Old French, ingenium, "ability") meant any piece of machinery. A "motor" (from Latin motor, "mover") is any machine that produces mechanical power. Traditionally, electric motors are not referred to as "engines," but combustion engines are often referred to as "motors."

Principles of operation

Reciprocating:

• Two-stroke cycle
• Four-stroke engine
• Sleeve valve four-stroke
• Crude oil engine
• Proposed
  • Bourke engine

Rotary:

• Demonstrated:
  • Wankel engine
• Proposed:
  • Orbital engine
  • Quasiturbine

Continuous combustion:

• Gas turbine
• Jet engine
• Rocket engine

 

Engine cycle

Engines based on the two-stroke cycle use two strokes (one up, one down) for every power stroke. Since there are no dedicated intake or exhaust strokes, alternative methods must be used to scavenge the cylinders. The most common method in spark-ignition two-strokes is to use the downward motion of the piston to pressurize fresh charge in the crankcase, which is then blown through the cylinder through ports in the cylinder walls. Spark-ignition two-strokes are small and light (for their power output), and mechanically very simple. Common applications include snowmobiles, lawnmowers, chain saws, jet skis, mopeds, outboard motors and some motorcycles. Unfortunately, they are also generally louder, less efficient, and far more polluting than their four-stroke counterparts, and they do not scale well to larger sizes. Interestingly, the largest compression-ignition engines are two-strokes, and are used in some locomotives and large ships. These engines use forced induction to scavenge the cylinders.

Engines based on the four-stroke cycle or Otto cycle have one power stroke for every four strokes (up-down-up-down) and are used in cars, larger boats and many light aircraft. They are generally quieter, more efficient and larger than their two-stroke counterparts. There are a number of variations of these cycles, most notably the Atkinson and Miller cycles. Most truck and automotive Diesel engines use a four-stroke cycle, but with a compression heating ignition system it is possible to talk separately about a diesel cycle.

The Wankel engine operates with the same separation of phases as the four-stroke engine (but with no piston strokes, would more properly be called a four-phase engine), since the phases occur in separate locations in the engine; however like a two-stroke piston engine, it provides one power 'stroke' per revolution per rotor, giving it similar space and weight efficiency. The Bourke cycle's combustion phase more closely approximates constant volume combustion than either four stroke or two stroke cycles do. It also uses less moving parts, hence needs to overcome less friction than the other two reciprocating types have to. In addition, its greater expansion ratio also means more of the heat from its combustion phase is utilized than is used by either four stroke or two stroke cycles.

1906 gasoline engine

Fuel and oxidizer types

Fuels used include gasoline (British term: petrol), liquified petroleum gas, vapourized petroleum gas, compressed natural gas, hydrogen, diesel fuel, JP18 (jet fuel), landfill gas, biodiesel, peanut oil, ethanol, methanol (methyl or wood alcohol). Even fluidised metal powders and explosives have seen some use. Engines that use gases for fuel are called gas engines and those that use liquid hydrocarbons are called oil engines. However, gasoline engines are unfortunately also often colloquially referred to as 'gas engines'.

The main limitations on fuels are that the fuel must be easily transportable through the fuel system to the combustion chamber, and that the fuel release sufficient energy in the form of heat upon combustion to make use of the engine practical.

The oxidiser is typically air, and has the advantage of not being stored within the vehicle, increasing the power-to-weight ratio. Air can, however, be compressed and carried aboard a vehicle. Some submarines are designed to carry pure oxygen or hydrogen peroxide to make them air-independent. Some race cars carry nitrous oxide as oxidizer. Other chemicals such as chlorine or fluorine have seen experimental use; but mostly are impractical.

Diesel engines are generally heavier, noisier and more powerful at lower speeds than gasoline engines. They are also more fuel-efficient in most circumstances and are used in heavy road vehicles, some automobiles (increasingly more so for their increased fuel efficiency over gasoline engines), ships, railway locomotives, and light aircraft. Gasoline engines are used in most other road vehicles including most cars, motorcycles and mopeds. Note that in Europe, sophisticated diesel-engined cars have become quite prevalent since the 1990s, representing around 40% of the market. Both gasoline and diesel engines produce significant emissions. There are also engines that run on hydrogen, methanol, ethanol, liquefied petroleum gas (LPG) and biodiesel. Paraffin and tractor vaporising oil (TVO) engines are no longer seen.

Some have theorized that in the future hydrogen might replace such fuels. Furthermore, with the introduction of hydrogen fuel cell technology, the use of internal combustion engines may be phased out. The advantage of hydrogen is that its combustion produces only water. This is unlike the combustion of hydrocarbons, which also produces carbon dioxide, a major cause of global warming, as well as carbon monoxide, resulting from incomplete combustion. The big disadvantage of hydrogen in many situations is its storage. Liquid hydrogen has extremely low density- 14 times lower than water and requires extensive insulation, whilst gaseous hydrogen requires very heavy tankage. Although hydrogen has a higher specific energy, the volumetric energetic storage is still roughly five times lower than petrol, even when liquified. (The 'Hydrogen on Demand' process, designed by Steven Amendola, creates hydrogen as it is needed, but this has other issues, such as the raw materials being relatively expensive.)

Single cylinder gasoline engine c. 1910

 

 

Cylinders

Internal combustion engines can contain any number of cylinders with numbers between one and twelve being common, though as many as 30 have been used. Having more cylinders in an engine yields two potential benefits: First. the engine can have a larger displacement with smaller individual reciprocating masses (that is, the mass of each piston can be less) thus making a smoother running engine (since the engine tends to vibrate as a result of the pistons moving up and down). Second, with a greater displacement and more pistons, more fuel can be combusted and there can be more combustion events (that is, more power strokes) in a given period of time, meaning that such an engine can generate more torque than a similar engine with fewer cylinders. The down side to having more pistons is that, over all, the engine will tend to weigh more and tend to generate more internal friction as the greater number of pistons rub against the inside of their cylinders. This tends to decrease fuel efficiency and rob the engine of some of its power. For high performance gasoline engines using current materials and technology (such as the engines found in modern automobiles), there seems to be a break point around 10 or 12 cylinders, after which addition of cylinders becomes an overall detriment to performance and efficiency, although exceptions such as the W-16 engine from Volkswagen exist.

• Most car engines have four to eight cylinders, with some high performance cars having ten, twelve, or even sixteen, and some very small cars and trucks having two or three. In previous years some quite large cars, such as the DKW and Saab 92, had two cylinder, two stroke engines.
• Radial aircraft engines, now obsolete, had from five to 28 cylinders. A row contains an odd number of cylinders, so an even number indicates a two- or four-row engine.
• Motor cycles commonly have from one to four cylinders, with a few high performance models having six.
• Snowmobiles usually have two cylinders. Some larger (not necessarily high-performance, but also touring machines) have four.
• Small portable appliances such as chainsaws, generators and domestic lawn mowers most commonly have one cylinder, although two-cylinder chainsaws exist.

 

Ignition system

Internal combustion engines can be classified by their ignition system. Today most engines use an electrical or compression heating system for ignition. However outside flame and hot-tube systems have been used historically. Nikola Tesla gained one of the first patents on the mechanical ignition system with U.S. Patent 609250, "Electrical Igniter for Gas Engines", on 16 August 1898.

Fuel systems

Often for simpler reciprocating engines a carburetor is used to supply fuel into the cylinder. However, exact control of the correct amount of fuel supplied to the engine is impossible.

Larger gasoline engines such as used in cars have mostly moved to fuel injection systems. LPG engines use a mix of fuel injection systems and closed loop carburetors. Diesel engines always use fuel injection.

Other internal combustion engines like jet engines use burners, and rocket engines use various different ideas including impinging jets, gas/liquid shear, preburners and many other ideas.

Engine configuration

Internal combustion engines can be classified by their configuration which affects their physical size and smoothness (with smoother engines producing less vibration). Common configurations include the straight or inline configuration, the more compact V configuration and the wider but smoother flat or boxer configuration. Aircraft engines can also adopt a radial configuration which allows more effective cooling. More unusual configurations, such as "H", "U", "X", or "W" have also been used.

Multiple-crankshaft configurations do not necessarily need a cylinder head at all, but can instead have a piston at each end of the cylinder, called an opposed piston design. This design was used in the Junkers Jumo 205 diesel aircraft engine, using two crankshafts, one at either end of a single bank of cylinders, and most remarkably in the Napier Deltic diesel engines, which used three crankshafts to serve three banks of double-ended cylinders arranged in an equilateral triangle with the crankshafts at the corners. It was also used in single-bank locomotive engines, and continues to be used for marine engines, both for propulsion and for auxiliary generators. The Gnome Rotary engine, used in several early aircraft, had a stationary crankshaft and a bank of radially arranged cylinders rotating around it.

Engine capacity

An engine's capacity is the displacement or swept volume by the pistons of the engine. It is generally measured in litres or cubic inches for larger engines and cubic centimetres (abbreviated to cc's) for smaller engines. Engines with greater capacities are usually more powerful and provide greater torque at lower rpms but also consume more fuel.

Apart from designing an engine with more cylinders, there are two ways to increase an engine's capacity. The first is to lengthen the stroke and the second is to increase the piston's diameter. In either case, it may be necessary to make further adjustments to the fuel intake of the engine to ensure optimal performance.

An engine's quoted capacity can be more a matter of marketing than of engineering. The Morris Minor 1000, the Morris 1100, and the Austin-Healey Sprite Mark II all had engines of the same stroke and bore according to their specifications, and were from the same maker. However the engine capacities were quoted as 1000cc, 1100cc and 1098cc respectively in the sales literature and on the vehicle badges.

Engine pollution

Generally internal combustion engines, particularly reciprocating internal combustion engines, produce moderately high pollution levels, due to incomplete combustion of carbonaceous fuel, leading to carbon monoxide and some soot along with oxides of nitrogen & sulfur and some unburnt hydrocarbons depending on the operating conditions and the fuel/air ratio.

Diesel engines produce a wide range of pollutants including aerosols of many small particles that are believed to penetrate deeply into human lungs.

• Many fuels contain sulfur leading to sulfur oxides (SOx) in the exhaust, promoting acid rain.
• The high temperature of combustion creates greater proportions of nitrogen oxides (NOx), demonstrated to be hazardous to both plant and animal health.
• Net carbon dioxide production is not a necessary feature of engines, but since most engines are run from fossil fuels this usually occurs. If engines are run from biomass, then no net carbon dioxide is produced as the growing plants absorb as much, or more carbon dioxide while growing.
• Hydrogen engines need only produce water, but when air is used as the oxidizer nitrogen oxides are also produced.

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Brainstorming

"Genius is one percent inspiration and ninety-nine percent perspiration." -- Thomas Alva Edison

What is Brainstorming?

Brainstorming is a process for developing creative solutions to problems. Alex Faickney Osborn, an advertising manager, popularized the method in 1953 in his book, Applied Imagination. Ten years later, he proposed that teams could double their creative output with brainstorming (Osborn, 1963).
Brainstorming works by focusing on a problem, and then deliberately coming up with as many solutions as possible and by pushing the ideas as far as possible. One of the reasons it is so effective is that the brainstormers not only come up with new ideas in a session, but also spark off from associations with other people's ideas by developing and refining them.
While some research has found brainstorming to be ineffective, this seems more of a problem with the research itself than with the brainstorming tool (Isaksen, 1998).
There are four basic rules in brainstorming (Osborn, 1963) intended to reduce social inhibitions among team members, stimulate idea generation, and increase overall creativity:

• No criticism: Criticism of ideas are withheld during the brainstorming session as the purpose is on generating varied and unusual ideals and extending or adding to these ideas. Criticism is reserved for the evaluation stage of the the process. This allows the members to feel comfortable with the idea of generating unusual ideas.
• Welcome unusual ideas: Unusual ideas are welcomed as it is normally easier to "tame down" than to "tame up" as new ways of thinking and looking at the world may provide better solutions.
• Quantity Wanted: The greater the number of ideas generated, the greater the chance of producing a radical and effective solution.
• Combine and improve ideas: Not only are a variety of ideals wanted, but also ways to combine ideas in order to make them better.

Brainstorming Steps:

• Gather the participants from as wide a range of disciplines with as broad a range of experience as possible. This brings many more creative ideas to the session.
• Write down a brief description of the problem - the leader should take control of the session, initially defining the problem to be solved with any criteria that must be met, and then keeping the session on course.
• Use the description to get everyone's mind clear of what the problem is and post it where it can be seen. This helps in keeping the group focused.
• Encourage an enthusiastic, uncritical attitude among brainstormers and encourage participation by all members of the team. Encourage them to have fun!
• Write down all the solutions that come to mind (even ribald ones). Do NOT interpret the idea, however you may rework the wording for clarity's sake. 
• Do NOT evaluate ideas until the session moves to the evaluation phase. Once the brainstorming session has been completed, the results of the session can be analyzed and the best solutions can be explored either using further brainstorming or more conventional solutions.
• Do NOT censor any solution, no matter how silly it sounds. The silly ones will often lead to creative ones - the idea is to open up as many possibilities as possible, and break down preconceptions about the limits of the problem.
• The leader should keep the brainstorming on subject, and should try to steer it towards the development of some practical solutions. 
• Once all the solutions have been written down, evaluate the list to determine the best action to correct the problem.

Brainstorming Variations

• One approach is to seed the session with a word pulled randomly from a dictionary. Use this word as a starting point in the process of generating ideas. 
• When the participants say they "can't think of any more ideas" then give them about 15 more minutes as the best ideas sometimes come towards the end of a longer thought process.
• Brainstorming can either be carried out by individuals or groups. When done individually, brainstorming  tends to produce a wider range of ideas than group brainstorming as individuals are free to explore ideas in their own time without any fear of criticism. On the other hand, groups tend to develop the ideas more effectively due to the wider range of diversity. 
• Keep all the generated ideas visible. As a flip chart page becomes full, remove it from the pad and tape it to a wall as that it is visible. This "combined recollection" is helpful for creating new ideals.
• If the brainstormers have difficulty in coming up with solutions, you may have to restate the problem in a different context, such as using metaphors or linking it to own knowledge.

Selecting a Solution

When you are sure the brainstorming session is over, it is time to select a solution:

• Use a show of hands (or another voting method) to allow each person to vote.
• Write the vote tallies next to the ideal.
• Once the voting is completed, delete all items with no votes. 
• Next, look for logical breaks. For example, if you have several items with 5 or 6 votes, and no 3 or 4 and only a couple of 1 and 2, then retain only the 5 and 6 votes. The group can help to decide the breaking point.
• Now, it is time to vote again. Each person gets half number of votes as there are ideals left. For example is you narrowed the number of generated ideals down to 20, then each person gets 10 votes (if it is a odd number, round down). Each person will keep track of his or her votes. The scribe should again tally the votes next to the ideal, only this time use a different color.
• Continue this process of elimination until you get down to about 5 ideals.
• Put the remainder ideas into a matrix. Put each ideal into its own row (first column). Next label some columns using selected criteria. For example:

Generated Idea	Low Cost	Easy to Implement and is Feasible	Will Help Other Processes	TOTAL
Outsource it to a vendor.
Hire a new employee.
Share the extra workload.

• Next, working one column at a time, ask the group to order each idea. Using the above example, which one will cost the least, the most, and will be in the middle.
• Repeat by working the next column until you have completed all columns. Total each column until it looks similar to this:

Generated Idea	Low Cost	Easy to Implement and is Feasible	Will Help Other Processes	TOTAL
Outsource it to a vendor.	2	2	2	6
Hire a new employee.	3	1	1	5
Share the extra workload.	1	3	3	7

• In this case, the lowest number column, "Hire a new employee," would be the best solution.
• Note that you should work each column first (not each row).
• Some of the columns will require much discussion, as choosing an arbitrary number will not be that easy in some cases.
• Often, you will have a couple of ideas that tie, but having it diagramed out in a matrix makes it easier to make a decision.

Radical Thinking and Successful Brainstorming

Once your team or company grows by more than one individual, ensure the new individual is one who truly thinks differently than you — to encourage radical thinking and effective brainstorming is truly diverse thinking styles on your team.And when you get another member, ensure that person's thinking style is different than yours and the other team member. And so on down the line. This is the first step in remaining competitive. Do not full into the trap of hiring someone like you or your favorite employee — this leads to group-think.

Doug Hall, who specializes in new business development, training, and consulting had this to say about team diversity, "The more diverse you are, the more likely you are to have loud and sometimes obnoxious debates. This is good. It means that all the folks have passion and a pulse. Remember, real teams are more like the family on the television show 'Roseanne' than they are like the Cleavers in 'Leave It to Beaver.' Real teams fight to make their point, yet they still have respect for each other."

In the Abilene Paradox, Dr. Harvey uses a parable to illustrate what he believes is a major symptom of organizational group-think: the management of agreement — as opposed to the management of disagreement or conflict. When we fail to engage in deep inquiry and in self-disclosure, we tend to agree with others, no matter if it is the best way to do so or not. Part of the reason this "management of agreement" comes about is that each individual's style is similar to other team members. When our interests our too similar, radical discourse fails to take place. For more information, see the section labeled, "Abilene Paradox"in Creativity.
Real team members should not be afraid to disagree, but once a decision has been made, they all need to be on the same bandwagon. They ensure their ideals and opinions are heard, but once it is time to go forward, they concentrate on getting there, not going back.
One often used technique for generating new ideals in a brainstorming session is to pick up a dictionary and toss out a random word. However, there is a better way to provide a climate of creativity. There is a game called Cranium that does a good job of using the various parts of the mind. You sketch, sculpt, draw with you eyes, use your knowledge, unscramble words, spell, hum, whistle, impersonate, etc. in order to get your team member(s) to discover the secret word or phase. You do these activities by drawing a card and then performing the activity before the timer runs out. For example, one team member might draw the word "Measure." The card tells her what type of activity to perform, such as drawing clues on a paper (no talking, letters, or symbols) with her eyes closed.
To use this game in brainstorming, play the game normally, except that after each card drawing activity has been performed, have all the participants generate x number of ideals before moving on to the next activity (normally 10 to 20 ideals). Normal brainstorming rules also apply. This may sound like a slower process than the regular brainstorming sessions we are used to, but remember, radical ideals are important for you organization to survive! And radical ideals come from creative activities. You cannot expect people to be creative by sitting in a room staring at four blank walls. The ideal is to get their creative juices flowing.
The Cranium game also performs an important function for radical thinking -- reducing the fear factor by providing fun. Fear is a barricade for new ideals. By providing fun and laughter, you create a pathway for radical ideals to emerge.

Out of the Box

"Thinking out of the box" is often used over and I hate it when I'm told to "get out of my box" (I'm on the shy side). However, as the steps to radical thinking and brainstorming show, you need radical thinking generators to reach a high creative level:

• Diverse thinking styles. You need lively discussions, not "Leave It to Beaver" dinner talk.
• Stimulus to spark the mind — activities that will get the creative juices flowing, such as the Cranium game.
• Fear prevention — fun games, friendly environment, and firm gestures that creates the feeling that everything is OK!

This is truly "thinking out of the box" as it provides an environment that uses everyone's thinking styles, rather than telling them to change their thinking style. When you tell people "to come out of the box," you are basically saying that you want them to be the same box as you. Now why would we go to all that trouble of getting a diverse workforce and then cloning everyone into the same style? When you provide a creative environment, instead of trying to change a person, you get the real person! When you get real persons into open, trusting environments with creative activities, you get radical thinking. And when you get radical thinking, you get the next great ideal for your organization!

How to Stop Great Ideas

"Inventions reached their limit long ago, and I see no hope for further development," - Julius Frontinus in the first century A.D.
"A cookie store is a bad idea. Besides, the market research reports say America likes crispy cookies, not soft and chewy cookies like you make." - Response to Debbi Fields' idea of starting Mrs. Fields' Cookies.
"Drill for oil? You mean drill into the ground to try and find oil? You're crazy." - Drillers who Edwin L. Drake tried to enlist to his project to drill for oil in 1859
"The concept is interesting and well-formed, but in order to earn better than a 'C,' the idea must be feasible." - A Yale University management professor in response to Fred Smith's paper proposing reliable overnight delivery service. (Smith went on to found Federal Express Corp.)
"Who the hell wants to hear actors talk?" - H.M. Warner, Warner Brothers, 1927.
"We don't like their sound, and guitar music is on the way out." - Decca Recording Co. rejecting the Beatles, 1962.
"I think there is a world market for maybe five computers." - Thomas Watson, chairman of IBM, 1943
"640K ought to be enough for anybody." - Bill Gates, 1981
"This 'telephone' has too many shortcomings to be seriously considered as a means of communication. The device is inherently of no value to us." - Western Union internal memo, 1876.
"The wireless music box has no imaginable commercial value. Who would pay for a message sent to nobody in particular?" - David Sarnoff's associates in response to his urgings for investment in the radio in the 1920s.
"I have traveled the length and breadth of this country and talked with the best people, and I can assure you that data processing is a fad that won't last out the year." - The editor in charge of business books for Prentice Hall, 1957
"But what ... is it good for?" - Engineer at the Advanced Computing Systems Division of IBM, 1968, commenting on the microchip.
"Computers in the future may weigh no more than 1.5 tons." - Popular Mechanics, forecasting the relentless march of science, 1949
"There is no reason anyone would want a computer in their home." - Ken Olson, president, chairman and founder of Digital Equipment Corp., 1977.
"Professor Goddard does not know the relation between action and reaction and the need to have something better than a vacuum against which to react. He seems to lack the basic knowledge ladled out daily in high schools." - 1921 New York Times editorial about Robert Goddard's revolutionary rocket work.
"I assure you, Marlon Brando will not appear in this film, " said a Paramount Studio exec about the casting of The Godfather.
"This 'telephone' has too many shortcomings to be seriously considered as a means of communication. The device is inherently of no value to us." - Western Union internal memo, 1876.
After Fred Astair's first screen test in 1933, the MGM testing director wrote a meme saying, "Can't act. Slightly bald. Can dance a little. " Astaire got the memo and kept it over his fireplace.
An expert said of football coach Vince Lombardi, "He possesses minimal football knowledge. Lacks motivation."
"So we went to Atari and said, 'Hey, we've got this amazing thing, even built with some of your parts, and what do you think about funding us? Or we'll give it to you. We just want to do it. Pay our salary, we'll come work for you.' And they said, 'No.' So then we went to Hewlett-Packard, and they said, 'Hey, we don't need you. You haven't got through college yet.'" - Apple Computer Inc. founder Steve Jobs on attempts to get Atari and H-P interested in his and Steve Wozniak's personal computer.
"I'm just glad it'll be Clark Gable who's falling on his face and not Gary Cooper," explained Gary Cooper on his refusal to take the leading role in "Gone With The Wind."
"If I had thought about it, I wouldn't have done the experiment. The literature was full of examples that said you can't do this." - Spencer Silver on the work that led to the unique adhesives for 3-M's Post-It notes

References

Isaksen, S. G. (1998). A Review of Brainstorming Research: Six Critical Issues for Research. Buffalo: Creative Problem Solving Group. Monograph 302. Retrieved March 5, 2010: http://www.cpsb.com/resources/downloads/public/302-Brainstorm.pdf
Osborn, A.F. (1963) Applied imagination: Principles and procedures of creative problem solving (3rd Ed.). New York:

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Venom Chemistry

Venoms contain many components that have beenrecognized. They contain proteins, lipids, steroids,aminopolysaccharides, amines, quinines, neurotransmitters, andother compounds, and are capable of causing many effects. Elapidvenom is the least complex, while pit vipers have the mostcomplex venoms. Elapid venoms have higher concentrations ofesterases, such as acetylcholinesterase, while viper venoms havehigher concentrations of endopeptidases. This difference isimportant because it helps understand why elapid venom exertseffects on the nervous system while viper venom is mainly asomatic toxin.

To better understand the diverse effects ofvenom, let us examine several of the common components found insnake venoms. Proteolytic enzymes are trypsin like and accountfor much of the digestive reactions of snake venoms. Theseenzymes break the peptide bonds between amino acids and denatureproteins. Arginine ester hyrdolases break carbon-oxygen bondsthat are not neurotransmitter related (neurotransmitter esteraseswill be explained in greater detail later), but rather causebreakup of certain proteins where arginine residues are frequent.Collagenase degrades collagen, which is a major component ofconnective tissue, skin and flexible vascular tissue. This enzymeis found in crotalid and viperid venoms and this explains thenecrosis often seen following viper bites. Phospholipases A and Bdegrade lipids to free fatty acids and can cause damage to thecell membrane causing lysis and apoptosis. Phosphodiesterasesbreak the phosphate bonds that provide the backbone for nucleicacids, thus rendering DNA and RNA useless in the effected cell,eventually causing apoptosis. Acetylcholinesterase is aneurotransmitter esterase that breaks the acetate ester bondfound in acetylcholine. The main site of action is in thesynapse, although some vesicle-contained acetylcholine may bedegraded as well. The end result of this action is an inabilityto enervate smooth muscle and the inability to relax striatedmuscle resulting in spasmodic paralysis and sometimes aconcurrent drop in blood pressure and difficulty breathing. Somevenoms also contain highly competitive antagonists that preventacetylcholine from binding at the postsynaptic membranereceptors, also causing neurotoxic symptoms and often apnea andasphyxiation will result. DNase and Rnase are enzymes thatdegrade DNA and RNA respectively. NAD Nucleotidase degradesnicotinamide, which is an important part of the cellularmetabolism machinery. Cellular respiration is interrupted andcell death may ensue. L-Amino acid oxidase is found in all knownsnake venoms. Procoagulants cause blood coagulation to occur;conversely Anticoagulants prevent blood from clotting. Bothchemicals may be found in the same venom, which is perplexingsince they may antagonize each other. Anticoagulant action ismore frequent and will cause bleeding at the site of envenomationas well as internal bleeding and tissue edema.

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