Showing posts with label energy. Show all posts
The Chernobyl nuclear disaster cases have been identified in human error and negligence - both in terms of reactor design and the operation of. In Japan these cases have been removed, here the design and operation of nuclear power plants is beyond doubt - at least, in the public image. Causes melting rods at Fukushima reactor inhibitors are not yet fully known, but most likely due to the earthquake that affected the nuclear infrastructure. And an earthquake can neither be foreseen nor prevented. Can plant in Fukushima was built to withstand earthquakes up to 8 on the Richter scale, but Friday's earthquake exceeded this level. Japanese engineers, however well trained and meticulous would not have prevented this chain of events.
Japan is a nation that is growing for decades apace and therefore energy needs. Meanwhile, Japan carries the flag clean energy sources that do not pollute the planet, doing more harm than good. And yet, despite these assumed principles, Japan could have scored a point in human history unhappy with a possible disaster in Fukushima.
Both Chernobyl and Fukushima nuclear power plant demonstrates the major dangers. Whether it was human error or a natural disaster, the mere existence of a nuclear extremely hazardous. However, the planet's energy resources are increasingly depleted, and human society is increasingly dependent on electricity. Gestures like lighting a bulb or opening computer or mobile phone charging commissioning of a washing machine somehow became part of nature and human existence. Most of us can not imagine having to live without electricity. And many will not be able to survive a world without electricity ... Electrical energy demand is met with reduced energy resources - coal pollutes the atmosphere, drained the oil resources, natural gas is becoming increasingly scarce and expensive. The solution proposed nuclear engineers was able to cover demand increasingly higher. Without too much technical detail, in nuclear power plants people try to reconstruct and control small replicas of the sun, the primary source of energy. But it is a dangerous game, as seen before.
Remain with the hope that the problems at Fukushima nuclear plant could be resolved and will be able to avoid a major disaster. But the warning remains valid - do not know what other central earthquake will strike in the future and whether the disaster will be avoided. A radioactive cloud affects not only the country where the accident occurs, but the entire planet.
History of energy
The only source of energy that fueled our civilization until this century was solar energy stored as chemical energy through the process of photosynthesis, in regenerative sources (wood, water, wind) or fossil fuels (coal, oil, gas ) whose constant training is millions of years.I could say quite safely shovel, that energy aspect we were "slaves of the Sun" and it is no wonder that ancient peoples made the Sun one of the main gods of primitive religion.
One major problem, whose solution depends on the development of our civilization, the issue returned to the plan of concerns in recent years is providing the energy needed to develop activities that condition the progressive development of the living standard of the population terrestrial globe. Cntitatea energy consumed by humanity increased primitive era so far, 2.5 million times. Obviously, such an increase can not be can not but lead to a problem of the energy needed for the future development of mankind .
Early atomic era
As I said not long ago we were "slaves of the sun", but I step towards emancipation was made by physicist Becqerel on February 26. 1898 when he left a few photographic plates protected from light, near a uranium ore. developandu discovers them blackened, as if they have been exposed to light here, he concluded that uranium ore emits radiation unknown. Therefore French physicists Marie Curie and Pierre Curie have dedicated many years of research radioactive radiation. Together, these three scientists received the Nobel Prize for physics in 1903. Identification and study of these radiation begins to passionate researchers.So at the beginning of our century Ruthefort and his pupils, Chadwick Walton Cockfroft and investigated the properties of nuclei by artificially accelerated particles larger than the kinetic energy of the radiation emitted by radioactive substances.
Radioactivity
Obtaining nuclear energy is conditioned by the presence of radioactive radiation. Radioactivity is presented as a phenomenon attended unstable nuclei that decay by emitting particles or radiation. rays are helium nuclei, less penetrating. They can even be stopped by a sheet of paper. Rays are electrons. They can be blocked by a sheet of aluminum. rays are pure energy. They can be blocked by the lead. We direct this type of radiation and on other atoms, as we bombard a target with missiles. Radioactive particles are designed to power the target nuclei. They "inflate" the mass of these nuclei or break them into fragments. Challenging these radiations phisics have the opportunity to study the structure of atoms in plants called accelerators. When bombarded with alpha rays which some atoms are radioactive. This phenomenon is called artificial radioactivity.Nuclear energy
Fusion underlies obtain nuclear energy. This process consists of absorption of a neutron by an atomic nucleus large as that of uranium, which will become unstable. He will break into several fragments, releasing great heat, which strongly accelareza fragments that reach very high speeds. Due to their high speed, these fragments following fission can enter in turn into other atoms, which cause other fissions.Uses of Nuclear Energy
Power generation in thermal power plants
In 1990 there were 435 nuclear power plants operating acoperind1% of global energy.In a nuclear reactor to obtain heat through radioactive decay of uranium-235 atoms. This is used to produce steam that moves the rotor turbines, generating electricitate.U-235 is a relatively rare isotope of uranium, accounting for only 7% of the total amount of uranium available. The rest is U-238 isotope. An isotope of an element is a form other isotopes chemically identical but different atomic mass. Like fossil fuels, U-235 will not last forever. There is a certain type of reactor, reactor called "growth" U-238 which turns into another radioactive element, plutonium-239. Pu-239 can be used to generate heat. So far only six countries have constructed experimental plants. Of these, nuclear reactor Phenix has the highest success. If this type of reactoarear become common, global reserves of uranium would reach thousands of years
Pros and cons of nuclear energy
Nuclear energy has many advantages. Is economic: a ton of U-235 produces more energy than insight by 12 million barrels of oil. Eate clean during use and does not pollute the atmosphere. Unfortunately there are some drawbacks. Nuclear power plants are very expensive. Produce radioactive waste that must be stored for hundreds of years before becoming harmless. A nuclear accident like the one that occurred in1986 at the Chernobyl nuclear plant in Ukraine, can contaminate large areas and can cause illness or death of hundreds of people.Researches are heading to discover new inexhaustible sources of energy. Some of them are already used.
Wind power (wind) afost used for centuries to propel ships and windmills drive. Modern wind turbines have been built can generate electricity. Only in California there are 15,000 such turbines. U.S. scientists calculated that the entire amount of energy could be generated by wind. Solar energy is the sun's heat on. Solar collectors in the form of panels can cover the energy needs of a house. Fuel cells made from silicon are used to produce energy in outer space.
The atomic bomb
In 1945, the principle of nuclear fission afost device used to an entirely different nature: the atomic bomb. In this case, the fission reaction is slow, it develops and takes place with huge energy release. The potential of this weapon was realized when on August 6, was released on Hiroshima, causing 150,000 casualties and later on Nagasaki August PE10, recording and there tens of thousands of deaths.Did you know ...
... a grain of uranium 238 can produce the same heat produced by the combustion of coal or 1 to 2.7 tons, 9 tons of oil?...uranium and thorium reserves are sufficient to ensure future energy consumption over a period of 7-8 hundred years, if fast reactors use uranium 238 in reproduction?
... if we could achieve the fusion reaction of deuterium with deuterium, then a cubic meter of water will have a content equivalent to 300 tons of coal or 1300 barrels of petrol. Energy reserves, in this case, are so great that no we have problems over a period of several thousand years?
The report published by British researchers shows that trees grown to produce biofuel - considered a cleaner alternative to coal and oil - a substance released into the air, mixed with other pollutants, causing reduced agricultural production.
"People think that biofuels are a good thing, because they reduce the level of carbon dioxide in the atmosphere," says Nick Hewitt, who worked on the study with colleagues at Lancaster University. "What we say is' yes, this is great, but biofuels can also have a detrimental effect on air quality," said Hewitt.
The report published in the scientific journal Nature Climate Change focused on the effects of a program designed by the European Union in which biofuels are produced more to combat climate change. Hewitt says that harmful effects are the same in every place where biofuels are produced in large quantities.
Poplars, willows and eucalyptus trees, three trees that grow quickly are used as a source of biofuel, emit a significant amount of isoprene as they grow, the researchers noted. Isoprene form ozone, a toxic substance when mixed in sunlight with other pollutants.
"Widespread production of biofuels in Europe would have little effect, but signified, the death rate and the productivity of agriculture," says Hewitt.
The report estimates that ozone generated trees used to achieve the target for 2020 set by the European Union would cause 1,400 premature deaths annually, costing the company $ 7.1 billion.
EU plan would reduce the annual amount of wheat and maize crop of 1.5 billion dollars, because ozone reduces productivity of the field, researchers say.
Scientists recommend placing biofuel plantations popluate far from urban centers to limit the production of ozone. They also say that genetic engineering could be used to reduce emissions of isoprene.
Ozone can cause lung problems, considered guilty for the deaths of 22,000 people each year in Europe. In total air pollution (caused mainly by fossil fuels) causes about 500,000 premature deaths each year in Europe.
Burning biofuels is considered to have neutral effects on climate change, because plants absorb carbon dioxide as they grow and release it when they burn or decompose. Fossil fuels, however, adds carbon dioxide to the atmosphere, releasing it from underground deposits.
Biofuels are considered responsible for higher food prices due to competition for agricultural land with plants that produce food crops. In response to these criticisms, the European Commission announced last year that it intended to limit biofuels from agriculture to 5% of all fuel used in transportation.
The geothermal system is composed of three parts: heat exchange unit with the ground heat pump itself and the air supply system. The heat exchanger consists of a set of pipes arranged in spiral, buried in the upper terrestrial crust, near the building. The heat transfer from the soil inside the house involves a series of operations consisting of evaporation, compression, condensation and expansion. The cycle starts when cold frigorofic agent passes through the heat exchanger and absorbs heat from the source, with lower temperatures.
What is a heat pump?
A device that transfers heat in the opposite direction that it has it in its natural movement. Thus, if the nature of the heat flows from the warmer body to the colder body, heat pump reverses the circuit, moving heat from a lower temperature source to a higher temperature heat sink. Heat pumps are refrigerators, freezers, air conditioners and heat inverters. When it comes to air conditioning, heat pump includes a two-way valve so that the direction of heat flow can be reversed: from the inside to the outside, while the interior has cooled (summer), or from the outside to the inside, when inside be heated (in winter). Usually, a reversible pump is a pump with lower efficiency one way (which may be cooling pump, or heating).What are the advantages and disadvantages of heat pump?
Probably the most important advantage of this system is that it provides fuel independence of any kind as they (gaseous, solid or liquid). It takes energy from the natural environment, potentially inexhaustible and delivered house to condition air to pre-heat the domestic water or the pool. Energy source can be soil, air or water surrounding groundwater. However, the pump can do these transfers without mechanical work, so without taking some energy. More clearly said, the installation can not transfer heat between the two environments without the use of a quantity of electricity. It consumes, the more electricity, as the temperature difference between the heated and the need to provide greater warmth. In other words, the energy efficiency of the heat pump is inversely proportional to the temperature difference between the two environments.Save energy, we live in harmony with nature and will protect future generations.
