Fuel Economy

by Charles Bartlett (Class of '06)

It is a well-known fact that the world has a limited supply of oil. Oil is used in a multitude of ways, but its most lucrative application is in the automotive industry due to its vast amount of stored energy. The oils used in the auto industry are usually derived from petroleum, and much of the world’s petroleum supply exists under some of the most politically instable and fanatical areas of the world. Finally, the emissions from oil and gasoline, which is also derived from petroleum, once the two are used to their potential in the internal combustion engine have been shown to have damaging effects on the earth’s atmosphere and ozone layer.

Do to these problems, some people have long been calling for an alternative to the use of oil and gasoline in the internal combustion engine, or for a different engine all together. This argument gained a lot of strength in the 1990s, due to all of the media coverage that global warming received. As much of the world’s oil supply is located in the Middle East, political and military uncertainty in the region further increases the demand for alternative power. In the last year or so, this demand has become even stronger due to the sharp spike in gasoline sales.

Currently, some promising alternatives to gasoline are the hybridization of gasoline engines to include electric power, and the use of either ethanol or hydrogen as fuel. Gas-electric hybrids have already been released on the automotive market. These cars use both electricity and gasoline or diesel fuel, and the result is much better gas mileage. Though there are many designs, the most common is that used in the Toyota Prius. When the car is at cruising speed, or at any other point when the car only needs a small thrust, the internal combustion part of the motor spins a generator, which either recharges the battery, or powers the electrical apparatus that propels the car. Other charging of the battery occurs during regenerative braking, where the braking system of the car captures some of the kinetic energy that would usually be lost to heat in normal cars. When the battery has been charged sufficiently, the car is able to switch to its electrical means of propulsion, and is thereby able to save immense amounts of fuel.Another promising alternative is the use of ethanol as a fuel. Brazil is leading the way in the use of ethanol, and produces its ethanol from sugarcane. The country recently announced that it no longer depends on Middle Eastern oil for its fuel. The United States is also pursuing the use of ethanol. The U.S. has long been a great producer of corn, and it will hopefully use much of its corn crop in the future to produce ethanol. The engines that use ethanol in the future will most likely be FlexFuel engines that can run on gasoline, ethanol, or any combination of the two.

Though the future of automotive fuel is still in question, the alternatives to gasoline and oilmake for safe and efficient driving in the future.

http://en.wikipedia.org/wiki/Regenerative_braking
http://en.wikipedia.org/wiki/Ethanol#Physical_properties
http://en.wikipedia.org/wiki/Hybrid_electric_vehicle

Black Hole Information Lost Forever? Not Quite, According to String Theory

by Sam Wass (Class of '06)

One of the most intriguing conclusions found by string theory, the proposed “theory of everything” which unifies the four fundamental forces (gravity, electromagnetism, strong nuclear force, weak nuclear force), regards one of the universe’s most bizarre objects: black holes. String theory applied to black holes suggests that black holes do not necessarily lose all of the information of the objects sucked inside of them. This resolves one of the greatest problems in modern physics, called the information paradox. Classical equations stipulated that the end result of a black hole was always the same, regardless of the matter put into it. However, this violates quantum mechanics, because it stipulates that processes must be traceable.

Black holes are one solution to Einstein’s equations of general relativity. They are the remnants of stars so massive that they collapsed in on themselves after their supernova, a massive explosion of a dying star. These bizarre objects have zero volume and infinite density, and are completely described by their electrical charge, angular momentum, and mass. It was long thought that information sucked into a black hole was lost forever, but string theory suggests that this may not be the case at all.

String theory, as its name indicates, suggests that the universe is composed of tiny “strings”, which are extremely small loops of energy. They vibrate in different ways, in very much the same was as a musical string would be plucked, and these different vibrations produce the different particles that science observes. Because of Einstein’s mass/energy equivalent (E=mc^2), the string at lower energies represent the least massive particles, while strings at high energies represent more massive particles.

If string theory is applied to black holes, then the singularity, or center of the black hole where the laws of physics do not apply, does not become so indescribable anymore. String theorists describe the singularity as a large mesh of strings, rather than a point in space. This mesh, or “fuzzball” as it is often called, would become very stretchy as it becomes more massive in order to create a supermassive object like a black hole. Scientists who tested the diameter of a black hole that would be produced using this method found that their answer closely approximated the diameter of classical equations.

If this postulate is correct, then information about the objects sucked into the black hole can be stored inside, and then reemitted via Hawking radiation, which happens when the black hole radiates its mass in the form of small particles. Until the application of string theory to black holes, it was believed that a black hole would destroy any information stored inside it. In order to justify this loss of information, quantum mechanics, the rules that govern the universe at its smallest scales, was thought to break down in black holes. However, the application of string theory shows that information stored in black holes is not lost, if string theory is proven to be correct.

References:

New Scientist, “Hawking Cracks Black Hole Paradox” by Jenny Hogan
http://www.newscientist.com/article.ns?id=dn6151

“Physics, M-Theory, and Black Holes"

"Information Paradox Solved? If So, Black Holes Are “Fuzzballs”"

Chronic Allergies

by Joseph Chang (Class of '06)

Currently, over 50 million Americans suffer from allergic diseases. In fact, 54.6 percent of US citizens test positive to one or more allergens, such as dust mites, rye, ragweed, and cockroach, according to a recent national survey. Allergies are already the sixth largest source of chronic disease for Americans and cost the US health care system about $18 billion annually. In addition, the rate of increase of allergy sufferers is about 5 percent per year; specifically, the number of Americans who suffer from asthma has increased over 100% from 20 years ago to about 20 million, today.

Allergies occur when the body’s immune system reacts to the presence of an innocuous substance, such as pollen or dander, as if it were a dangerous pathogen, such as a virus or bacterium. The development of an allergy begins when the body is exposed to a protein in a harmless molecule and recognizes it as a possible danger. On the first exposure, the body produces specific antibodies called immunoglobulin E (IgE) antibodies which recognize the protein. These IgE antibodies then attach to mast cells, which are responsible for creating various chemicals, such as histamine, prostaglandins and leukotrienes, which jolt the body into anti-pathogen maneuvers, including inflammation and mucus production. The first time the body is exposed to these allergens, there will likely be no symptoms; however, the second time the body comes in contact with the allergens, the IgE molecules recognize the offending proteins and trigger the release of the mast cells’ chemicals and cause the typical stuffed nose and headache allergy-symptoms.

One of the major causes of allergies, as with many other ailments, is based on genetics. Studies show that children with one asthmatic parent have greater chances have having asthma than children with no asthmatic parents. Children with two asthmatic parents have even greater chances of having asthma. In addition, pairs of identical twins, who share the same DNA, have asthma more frequently than pairs of fraternal twins, who do not share the same exact DNA. However, genetics alone does not explain the dramatic increase in allergy rates over the past few decades.

A second cause of allergies is the diet. The reduced fresh fruit and vegetable intake and the corresponding low level of antioxidants and minerals in the American diet both increase the risk of getting allergies. In addition, antibiotic use may be helping the rise of allergies by killing of certain bacteria in the intestine which suppress allergy.

Additionally, the environment plays an enormous role in whether or not Americans develop allergies. Environmental pollution, especially airborne pollution, is often cited as sources of allergies. One example of the pollution on allergies is a study which showed that children who live near major highways and are exposed to diesel fumes exhibit increased sensitivity to allergens that they already react to. Another environmental factor that is being considered as a source of allergies is excessive cleanliness. Essentially, this idea of excessive cleanliness causing allergies, called the hygiene hypothesis, states that immune systems must be exposed to certain levels of pathogens when they are young. If developing immune systems do not come in contact with enough pathogens they will be unable to distinguish between harmless substances and true dangers to the body.

References:

“Allergy Statistics.” National Institute of Allergy and Infectious Diseases. http://www.niaid.nih.gov/factsheets/allergystat.htm. May 30, 2006.

Newman, Judith. “Misery for All Seasons; Allergies: A Modern Epidemic.” National Geographic. May 2006.