Electricity

Electricity is the flow of free electrons through a conductor. Each of these free electrons jumps from one atom to another within the conductor. A free electron is an electron lost by an atom in the material conductor an is drawn towards another atom which has already lost one, thus giving rise to a continuous flow of electrons from atom to atom within the material the conductor is made of.

All matter is made up of atoms. An atom has protons, which are positively charged, in its nucleus, and the same amount of electrons orbiting about the nucleus. As electrons are negatively charged, an atom is in equilibrium, or balanced, when it has not lost an orbiting electron. When an atom has lost an electron, it becomes a positive +ion, since it contains more protons than the negatively charged electrons. When it has gained one, we call it a negative -ion, since it now has more negatively charged electrons than positively charged protons. So, when one atom loses an electron, it will always tend to draw, or gain, a new one towards itself to recover its internal equilibrium.

Not all materials allow this constant flow of electrons when the conditions for which are created. There are good materials and bad ones. The materials which allow the flow of electrons are called conductive materials. Those that do not allow are called non-conductive materials. For example, metals are excellent conductors, specially aluminum and copper. On the other hand, materials such as wood, glass, and plastic are non-conductive materials, or insulating materials.

In electricity this flow of electrons within a conductor is called electric current. And there are two kinds of electric current. Direct current and alternating current.

Ocean Current

An ocean current is any of the number of river-like, moving masses of water flowing in all oceans, each having a characteristic direction, length, depth, speed, and temperature. This great flow of global conveyor belts is caused by the planet rotation, the gravitation of the moon, the wind, temperature, and salinity differences. Warm ocean currents are corridors of warm water moving from the tropics poleward where they release energy to the air. Cold ocean currents are corridors of cold water moving from higher latitudes toward the equator where they absorb the energy received in the tropics as they cool the air above.

Although some ocean currents result from density and salinity variations of water, the major ocean currents are wind-driven currents. Surface currents make up about 10% of all the water in the ocean. These waters are the upper 400 meters of the ocean. Deep water currents make up the other 90% of the ocean; these waters move around the ocean basins by density driven forces and gravity. Density difference is a function of different temperatures and salinity.

Ocean currents can flow for thousands of kilometers. They are very important in determining the climates of the continents, especially those regions bordering on the ocean. Perhaps the most striking example is the Gulf Stream, which makes northwest Europe much more temperate than any other region at the same latitude. Another example is the Hawaiian Islands, where the climate is cooler than the tropical latitudes in which they are located because of the California Current.

The Tides

The tides are the periodic rising and falling of the surface of the oceans, and of bodies of water connected with the ocean such as bays and gulfs. The tides are caused by the gravitational attraction of the moon and sun, occurring unequally on different parts of the earth. In each lunar day of 24 hours and 51 minutes there are two high tides and two low tides, alternating at equal intervals of flood and ebb.

Tides cause changes in the depth of the sea and estuary water bodies, producing oscillating currents known as tidal streams. The strip of seashore that is submerged at high tide and exposed at low tide is an important ecological product of ocean tides. Tidal phenomena can also occur in other systems besides the ocean, whenever a gravitational field that varies in time and space is present.

Lightning

Lightning is a flash of light caused by the discharge of atmospheric electricity from one cloud to another or between a cloud and the earth. The discharge of electricity occurs when the clouds have become electrically charged, that is to say ionized, positively and negatively. A bolt of lightning can travel at speeds of 70,000 meter per second, reaching temperatures of 30,000º C. Lightning can also occur within the ash clouds from volcanic eruptions, or can be caused by violent forest fires which generate sufficient dust to create a static charge.

Aurora borealis

Aurora borealis is a luminous phenomenon which consists of streamers of light appearing in the upper atmosphere of the northern hemisphere, near the polar regions. It is caused by the emission of light from atom excited by electrons accelerated along the planet's magnetic field lines. The aurora borealis is also called the northern polar lights, for it is only visible in the sky from the northern hemisphere, the chance of visibility increasing with proximity to the northern magnetic pole. The aurora borealis was named after Roman goddess of dawn, Aurora, and the Greek name for the north wind, Boreas.

Rainbow

A rainbow is a natural phenomenon in which the colors of the spectrum appear in the sky in the form of an arc, caused by the refraction and reflection of the sun's ray when it shines onto small drops of moisture in the Earth's atmosphere. Rainbows can be seen when it is partially raining while the sun shines slantingly through a clearing in the clouds on raindrops, but the rainbow effect is also commonly observed near waterfalls or mist.

All raindrops refract and reflect the sunlight in the same way, but only the light from some raindrops reaches the observer's eye. The position of a rainbow in the sky is always in the opposite direction of the sun with respect to the observer. Thus, the rainbow apparent position depends on the observer's location and the position of the sun.

Blizzard

A blizzard is a harsh winter storm condition characterized by low temperatures, strong winds, and heavy blowing snow. Blizzards are formed when a high pressure system interacts with a low pressure system. This results in the advection of air from the high pressure zone into the low pressure area. The term blizzard is sometimes misused by news media to describe a large winter storm that does not actually satisfy official blizzard criteria.

A winter storm must have winds of 30 mph or more, have snow or blowing snow, visibility less than 1 mile, a wind chill of less than −25 °C (−13 °F), and that all of these conditions must last for 4 hours or more before the storm can be properly called a blizzard. In North America, blizzards are particularly common to the extreme portions of the Northeastern United States, the Northern Great Plains in the United States, Atlantic Canada, and the Canadian Prairie Provinces. Blizzard conditions also occur frequently in the mountain ranges in western North America, however since these regions are sparsely populated they are often not reported.

Snow

Snow is precipitation in the form of tiny ice crystals called snowflakes. Ice crystals form when supercooled cloud droplets freeze. In order to freeze, a few molecules in the liquid droplet need to get together to form an arrangement close to that in an ice lattice. Then the droplet freezes around this arrangement of molecules. Homogeneous nucleation of cloud droplets only happens at temperatures colder than -35°C. In warmer clouds an aerosol particle, also called 'ice nucleus', must be present in the droplet to act as a nucleus.

The crystals grow in size as they join together, becoming heavy and then dropping down through the cloud. Although there are different crystal shapes, snowflakes are always six-sided, with some having six branches sticking out of the central core. Ice crystals formed in the appropriate conditions can often be thin and flat. Planar crystals (thin and flat) grow in air between 0 °C (32 °F) and −3 °C (27 °F). Between −3 °C (27 °F) and −8 °C (18 °F), the crystals will form needles. Snow remains on the ground until it melts. In colder climates the snow lies on the ground all winter; and when the snow does not all melt in the summer, they become glaciers.

Nuclear Fusion Power Plant

The International Thermonuclear Experimental Reactor (Iter) will be the most expensive joint scientific project after the International Space Station. It is an engineering proposal for an experimental project that will help to make the transition from today's studies of plasma physics to future electricity-producing fusion power plants. The Iter programme had been held up for over 18 months as parties tried to broker a deal between the two rivals; Japan and France.

Finally France got to host the project to build a 10bn-euro (£6.6bn) nuclear fusion reactor, in the face of strong competition from Japan. Nuclear fusion is seen as a cleaner approach to power production than nuclear fission and fossil fuels. Officials from a six-party consortium signed the deal in Moscow on June 28, 2005, for the reactor's location at the Cadarache site in southern France. The construction began by the end of 2005 and the first plasma operation is expected in 2018. The European Union, the United States, Russia, Japan, South Korea and China are partners in the project.

The objective of the ITER machine is to demonstrate the scientific feasibility of fusion, with extended controlled burn and, marginally, ignition, for a duration sufficient to achieve stationary conditions on all time-scale characteristics of plasma processes and plasma-wall interactions. To do so the installation will produce 500 MW of fusion power during pulses of at least 400 seconds. According to the ITER consortium, fusion power offers the potential of being environmentally benign, widely applicable and essentially inexhaustible electricity, properties that they believe will be needed as world energy demands increase while simultaneously greenhouse gas emissions must be reduced, justifying the expensive research project.

The basic fuels - deuterium and lithium – and the reaction product - helium - are not radioactive. The intermediate fuel – tritium – is radioactive and decays very quickly, producing a very low energy electron (Beta radiation). In air, this electron can only travel a few millimetres and cannot even penetrate a piece of paper. Nevertheless, tritium would be harmful if it entered the body, so the facility will have very thorough safety facilities and procedures for the handling and storage of tritium. As the tritium is produced in the reactor chamber itself, there are no issues regarding the transport of radio-active materials.

The fuel consumption of a fusion power station will be extremely low. A 1 GW fusion plant will need about 100 kg of deuterium and 3 tons of natural lithium to operate for a whole year, generating about 7 billion kWh, with no greenhouse gas or other polluting emissions. To generate the same energy, a coal-fired power plan (without carbon sequestration) requires about 1.5 million tons of fuel and produces about 4-5 million tons of CO2. The neutrons generated by the fusion reaction cause radio-activity in the materials surrounding the reaction – so the walls of the container etc. A careful choice of the materials for these components will allow them to be released from regulatory control and possibly recycled about 100 years after the power plant stop operating. Waste from fusion plants will not be a burden for future generations.

Heavy Water

Heavy water is chemically the same as regular water, but with the two hydrogen atoms (as in H2O) replaced with heavy hydrogen atoms called deuterium, hence the symbol D2O of heavy water. Deuterium is an isotope of hydrogen and it has one extra neutron. Thus the deuterium atom consists of one proton and one neutron in the atomic nucleus with one electron orbiting around. It is the extra neutron that makes heavy water "heavy", about 10% heavier in fact.

Hydrogen / Deuterium / Tritium

Ordinary water / Heavy water

Nuclear Fusion

Nuclear fusion is the process by which two light atomic nuclei unite into one to form one heavier nucleus with the subsequent release of energy. Nuclear fusion occurs naturally in stars, but artificial fusion has also been achieved, although not yet completely controlled. When light nuclei are forced together, they will fuse with a release of energy because the mass of the combination will be less than the sum of the masses of the individual nuclei. For the artificial nuclear fusion, man has used two heavy hydrogen atoms; deuterium and tritium.

Deuterium-Tritium fusion yields 17.6 MeV of energy but requires a temperature of approximately 40 million Kelvins to overcome the coulomb barrier and ignite it. Thus, it takes considerable energy to force nuclei to fuse, even those of the lightest element, hydrogen. This is because all nuclei have a positive charge due to their protons, and as like charges repel each other, nuclei strongly resist being put too close together. Heated to thermonuclear temperatures, they can overcome this electromagnetic repulsion and get close enough for the attractive nuclear force to be sufficiently strong to achieve fusion.

When the fusion reaction is a sustained uncontrolled chain, it can result in a thermonuclear explosion, such as that generated by a hydrogen bomb, which is triggered not by TNT, but by an atomic bomb! The central core of a hydrogen bomb is a mass made up of trillions of deuterium and tritium (isotopes of hydrogen). These hydrogen atoms have one or two extra neutrons in each nucleus. Small atomic bombs (A) scattered around the outside of the core cause the deuterium and tritium to be squeezed into a very dense mass, which initiates a process called nuclear fusion, releasing great quantities of energy.

Producing fusion power for the production of electricity is not easy as research into controlled fusion has been conducted for 50 years. It has been accompanied by extreme scientific and technological difficulties, and it resulted in steady progress. Controlled fusion reaction have been demonstrated in a few tokamak-type reactors around the world. As a result, a workable design of a reactor was produced. It will deliver ten times more fusion energy than the amount of energy needed to heat up its plasma to required temperatures.


Fusion Bomb

Two Japanese and One American Win Nobel Prize For Physics

STOCKHOLM - Two Japanese scientists and a Tokyo-born American shared the 2008 Nobel Prize for physics for discoveries in sub-atomic particles, the prize committee said on Tuesday.

The Nobel committee lauded Yoichiro Nambu, a Tokyo-born American citizen, and Makoto Kobayashi and Toshihide Maskawa of Japan for separate work that helped explain why the universe is made up mostly of matter and not anti-matter via processes known as broken symmetries. They helped figure out the existence and behavior of the very tiniest particles known as quarks.

Nambu, a professor at the University of Chicago, was recognized for his discovery of the mechanism of spontaneous broken symmetry. It helps underlie the Standard Model of physics, which unites three of the four fundamental forces of nature: strong, weak and electromagnetic, leaving out gravity.

Nambu also influenced the development of quantum chromodynamics, a theory that describes some of the interactions between protons and neutrons, which make up atoms, and the quarks that make up the protons and neutrons.

Nambu shared half of the prestigious 10 million Swedish crown ($1.4 million) prize with Kobayashi of Japan's High Energy Accelerator Research Organization and Maskawa of Kyoto University.

Kobayashi and Maskawa proposed the six types of quarks -- up, down, strange, charm, bottom, and top. All were later discovered in high-energy particle physics experiments.

"The fact that our world does not behave perfectly symmetrically is due to deviations from symmetry at the microscopic level," the committee said. This broken symmetry allowed particles of matter to outnumber particles of anti-matter.

This is lucky for all living things -- because if the universe were symmetrical, anti-matter would be constantly meeting matter and exploding in a burst of energy.

Kobayashi said the news came as a shock. "It is my great honor and I can't believe this," he said. But Maskawa said he was not surprised.

"There is a pattern to how the Nobel prize is awarded. I did not think I would get the award up until last year, but I predicted it pretty much this year," he was quoted as saying by Kyodo news agency.

"I am very happy that Professor Yoichiro Nambu was awarded. I myself am not that happy. It's a noisy celebration for society."

Physicists are now searching for the spontaneous broken symmetry, the Higgs mechanism, which threw the universe into its current imbalance at the time of the Big Bang 13.7 billion years ago.

This Higgs mechanism gave the particles their masses and there should be a Higgs particle, theory predicts. Scientists at the world's most powerful particle accelerator, the Large Hadron Collider at the European Organization for Nuclear Research or CERN in Switzerland, will be looking for this particle when they re-start the collider in spring of 2009.

The prize, awarded by the Nobel Committee for Physics at the Royal Swedish Academy of Sciences, was the second of this year's crop of Nobel prizes.

Three Europeans Win The 2008 Nobel Prize For Medicine

Three European scientists who discovered viruses that cause cervical cancer and AIDS share this year’s Nobel Prize in medicine. A German virologist, Harald zur Hausen, will receive half the award for his discovery of H.P.V., the human papilloma virus, according to the announcement made on Monday by the Karolinska Institute in Stockholm, which selects the medical winners of the prize. The discovery led to development of a vaccine against cervical cancer, the second most common cancer among women.

The institute said the other half of the award will be shared equally by two French virologists, Francoise Barre-Sinoussi and Luc Montagnier, for discovering H.I.V., the virus that causes AIDS. Since its discovery in 1981, AIDS has rivaled the worst epidemics in history. An estimated 25 million people have died, and 33 million more are living with H.I.V.

Dr. zur Hausen of the University of Heidelberg was cited for discovering the first H.P.V., type 16, in 1983 from biopsies of women who had cervical cancer. A year later, Dr. zur Hausen cloned H.P.V. 16 and another type, 18. The two H.P.V. types are consistently found in about 70 percent of cervical cancer biopsies throughout the world, the institute said.

Of the more than 100 human papilloma viruses now known, about 40 infect the genital tract, and 15 of them put women at high risk for cervical cancer. Papilloma viruses account for more than 5 percent of all cancers worldwide.

The Karolinska Institute said that discovery of H.I.V. by the French scientists, Dr. Barre-Sinoussi and Dr. Montagnier, led to blood tests to detect the infection and to anti-retroviral drugs that are effective in prolonging the lives of patients. The tests are now used to screen blood donations, making the blood supply safer for transfusions. The viral discovery has also led to an understanding of the natural history of H.I.V. infection in people, which ultimately leads to AIDS unless treated.

H.I.V. is a member of the lentivirus family of viruses. The French scientists were cited for identifying what is now known as H.I.V. in lymph nodes from early and late stages of the infection.

“Never before has science and medicine been so quick to discover, identify the origin and provide treatment for a new disease entity,” the Karolinska Institute said.

Nobel Foundation rules limit the number of recipients of its medical prizes to a maximum of three each year, and omissions often create controversy. This year, the Karolinska committee excluded an AIDS virologist, Dr. Robert C. Gallo, who worked for many years at the National Cancer Institute in Bethesda, Md., before moving to the University of Maryland in Baltimore.

Dr. Gallo and the French team have vied in a long-running dispute over credit for the discovery of H.I.V. and the development of a test to detect it in blood. In 1987, President Reagan and Jacques Chirac, who was then prime minister of France, signed an agreement that allowed the two countries’ institutes to share millions of dollars of royalties and credit for the discovery.

Dr. Gallo told the Associated Press on Monday that it was “a disappointment” not to have been honored with the French team. Dr. John E. Niederhuber, the director of the National Cancer Institute, said Monday that Dr. Gallo “was instrumental in every major aspect of the discovery of the AIDS virus.” He added: “Dr. Gallo discovered interleukein-2 (Il-2), an immune system signaling molecule, which was necessary for the discovery of the AIDS virus, serving as a co-culture factor that allowed the virus to grow. Numerous scientific journal articles, many co-authored by Dr. Gallo and Dr. Luc Montagnier, cite the two scientists as co-discoverers of the AIDS virus.”

Dr. Anthony S. Fauci, a virologist and immunologist who directs the National Institute of Allergy and Infectious Diseases, said he was delighted that the Karolinska committee honored the discoverers of two viruses that cause two important diseases.

“There’s no doubt that Bob Gallo made enormous contributions to AIDS research, and if the Nobel rules allowed four recipients, Bob would belong in the group” that was honored on Monday, Dr. Fauci said in an interview.

Thrombosis

Thrombosis is the clotting of blood within a vein or artery, blocking the free circulation of blood. When a blood vessel is injured, the body uses platelets and fibrin to form a blood clot, as the first step in repairing it to prevent loss of blood. If that mechanism causes too much clotting, and the clot breaks free, a thrombus is formed.

But the more common causes of thrombosis are old age and obesity, which lead to the formation of plaques within the blood vessels. When a piece of plaque breaks off an artery wall, it turns into a clot that obstruct the flow of blood, causing thus a stroke or a heart attack, depending on the area of the circulatory system where this plug of bood ends up.

There are two kinds of thrombosis: 1) venous thrombosis; a blood clot that develops in a vein. 2) arterial thrombosis; a blood clot that develops in an artery. One of the most common types of venous thrombosis is deep vein thrombosis (DVT), which is a blood clot in one of the deep veins of the body. It most commonly affects leg veins, such as the femoral vein.

Atherosclerosis (Arteriosclerosis)

Atherosclerosis is the thickening and hardening of blood vessels, accompanied by the deposit of fat on the inner arterial walls. We can also say that atherosclerosis is the slow process in which deposits of fatty substances, cholesterol, waste products of cells (macrophage white blood cells), and calcium build up in the inner lining of an artery. This buildup is called plaque, and usually affects large and medium-size arteries.

Over the years, as people grow old, the buildup of fatty material and calcium gets thicker and harder, significantly reducing the blood's flow through an artery. But most of the damage occurs when the a piece of plaque break off. When a piece of plaque breaks off, it can turn into a blood clot that sometimes travels to another part of the body, to a smaller blood vessel in the brain, for example, reducing the flow of oxygen-rich blood to a certain area of the brain and producing memory loss or other cerebral dysfunctions.

Atherosclerosis, or arteriosclerosis, can lead to serious problems, including heart attack, stroke, or even death. Scientists think it begins with damage to the innermost layer of the artery. This layer is called the endothelium. Causes of damage to the arterial wall include elevated levels of cholesterol and triglyceride in the blood, high blood pressure, tobacco smoke, and diabetes. Tobacco smoke greatly worsens atherosclerosis and speeds its growth in the coronary arteries, the aorta and arteries in the legs.

Stroke (Cerebrovascular Accident)

Stroke is the loss of brain functions due to a hindrance to the normal blood flow in the brain. As they do not receive oxygen-rich blood, the nerve cells in the affected area of the brain begin to die within minutes after the blood has stopped circulating.

There are two kinds of stroke. One kind of stroke is caused by a blood clot which plugs a blood vessel in the brain; this stroke is often referred to as thrombosis. The other kind of stroke is caused by a cerebral hemorrhage due to a blood vessel rupture; this happens when the blood pressure rises to very high levels to a point where a blood vessel can no longer withstand the inner pressure, bursting and bleeding, thus interrupting the normal blood supply to the neurons.

Stroke can cause serious neurological damage, rendering the affected person unable to move one or both limbs on one side of the body, and also leading to inability to understand and produce speech. Depending on the area of the brain where the blood flow stops, a stroke can sometimes cause death, especially when there is a massive brain hemorrhage.

Also called cerebrovascular accident, or ictus, stroke symptons arise suddenly and they are weakness of the face, arm drift, abnormal speech, confusion, trouble seeing in one or both eyes, trouble walking, loss of balance, dizziness, headache. When this happens people should immediately called for assistance.

Blood Vessels

Located throughout the body, the blood vessels are hollow, elastic tubes through which the blood flows, forming a network of interconnecting arteries, arterioles, capillaries, venules, and veins. Besides circulating blood, the blood vessels provide two important means of measuring vital health statistics: pulse and blood pressure. The blood vessels are part of the circulatory system.

Arteries are the passageways through which the blood circulates, the largest of which is the aorta. The aorta branches off the heart and divides into many smaller arteries called arterioles, which have muscular walls that adjust their diameter to increase or decrease blood flow to a particular body area. Arteries and arterioles carry oxygenated blood from the lungs to the rest of the body.

Capillaries are thin walled, highly branched vessels that feed the tissues and collect wastes and carbon dioxide to be carried back to the lungs, liver, or kidney for elimination. Capillaries empty into the venules, which in turn drain into the veins that lead back to the heart, which in turn pumps deoxygenated blood to the lungs to pick up more oxygen, and then back to the heart once again.

Arteries and veins have the same basic structure as they are made up of three layers of tissues: 1) elastic tissue called tunica intima; 2) smooth muscle, tunica media; 3) connective tissue, tunica adventitia. The walls of arteries contain smooth muscle fibre that contract and relax under the instructions of the sympathetic nervous system. Arterioles are also under the control of the sympathetic nervous system, as they constrict and dialate to regulate blood flow. Capillary walls are only one cell thick, which allows exchanges of material between the contents of the capillary and the surrounding tissue.