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Emissions
Emission may refer to: Chemical products * Emission of air pollutants, notably: **Flue gas, gas exiting to the atmosphere via a flue ** Exhaust gas, flue gas generated by fuel combustion ** Emission of greenhouse gases, which absorb and emit radiant energy within the thermal infrared range * Emission standards, limits on pollutants that can be released into the environment * Emissions trading, a market-based approach to pollution control Electromagnetic radiation * Emission spectrum, the frequencies of electromagnetic radiation generated by molecular electrons making transitions to lower energy states * Thermal emission, electromagnetic radiation generated by the thermal motion of particles in matter * List of light sources, including both natural and artificial processes that emit light * Emission (radiocommunications), a radio signal (usually modulated) emitted from a radio transmitter * Emission coefficient, a coefficient in the power output per unit time of an electromagneti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Emission Of Greenhouse Gases
Greenhouse gas emissions from human activities strengthen the greenhouse effect, contributing to climate change. Most is carbon dioxide from burning fossil fuels: coal, oil, and natural gas. The largest emitters include coal in China and large oil and gas companies, many state-owned by OPEC and Russia. Human-caused emissions have increased atmospheric carbon dioxide by about 50% over pre-industrial levels. The growing levels of emissions have varied, but it was consistent among all greenhouse gases (GHG). Emissions in the 2010s averaged 56 billion tons a year, higher than ever before. Electricity generation and transport are major emitters; the largest single source, according to the United States Environmental Protection Agency, is transportation, accounting for 27% of all USA greenhouse gas emissions. Deforestation and other changes in land use also emit carbon dioxide and methane. The largest source of anthropogenic methane emissions is agriculture, closely followed by g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Emissions Trading
Emissions trading is a market-based approach to controlling pollution by providing economic incentives for reducing the emissions of pollutants. The concept is also known as cap and trade (CAT) or emissions trading scheme (ETS). Carbon emission trading for and other greenhouse gases has been introduced in China, the European Union and other countries as a key tool for climate change mitigation. Other schemes include sulfur dioxide and other pollutants. In an emissions trading scheme, a central authority or governmental body allocates or sells a limited number (a "cap") of permits that allow a discharge of a specific quantity of a specific pollutant over a set time period. Polluters are required to hold permits in amount equal to their emissions. Polluters that want to increase their emissions must buy permits from others willing to sell them. Emissions trading is a type of flexible environmental regulation that allows organizations and markets to decide how best to meet polic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Air Pollution
Air pollution is the contamination of air due to the presence of substances in the atmosphere that are harmful to the health of humans and other living beings, or cause damage to the climate or to materials. There are many different types of air pollutants, such as gases (including ammonia, carbon monoxide, sulfur dioxide, nitrous oxides, methane, carbon dioxide and chlorofluorocarbons), particulates (both organic and inorganic), and biological molecules. Air pollution can cause diseases, allergies, and even death to humans; it can also cause harm to other living organisms such as animals and food crops, and may damage the natural environment (for example, climate change, ozone depletion or habitat degradation) or built environment (for example, acid rain). Air pollution can be caused by both human activities and natural phenomena. Air pollution is a significant risk factor for a number of pollution-related diseases, including respiratory infections, heart dis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Emission Standard
Emission standards are the legal requirements governing air pollutants released into the atmosphere. Emission standards set quantitative limits on the permissible amount of specific air pollutants that may be released from specific sources over specific timeframes. They are generally designed to achieve air quality standards and to protect human life. Different regions and countries have different standards for vehicle emissions. Regulated sources Many emissions standards focus on regulating pollutants released by automobiles (motor cars) and other powered vehicles. Others regulate emissions from industry, power plants, small equipment such as lawn mowers and diesel generators, and other sources of air pollution. The first automobile emissions standards were enacted in 1963 in the United States, mainly as a response to Los Angeles' smog problems. Three years later Japan enacted their first emissions rules, followed between 1970 and 1972 by Canada, Australia, and several E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exhaust Gas
Exhaust gas or flue gas is emitted as a result of the combustion of fuels such as natural gas, gasoline (petrol), diesel fuel, fuel oil, biodiesel blends, or coal. According to the type of engine, it is discharged into the atmosphere through an exhaust pipe, flue gas stack, or propelling nozzle. It often disperses downwind in a pattern called an ''exhaust plume''. It is a major component of motor vehicle emissions (and from stationary internal combustion engines), which can also include crankcase blow-by and evaporation of unused gasoline. Motor vehicle emissions contribute to air pollution and are a major ingredient in the creation of smog in some large cities. A 2013 study by the Massachusetts Institute of Technology (MIT) indicates that 53,000 early deaths occur per year in the United States alone because of vehicle emissions. According to another study from the same university, traffic fumes alone cause the death of 5,000 people every year just in the United Kingdom. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Emission Spectrum
The emission spectrum of a chemical element or chemical compound is the spectrum of frequencies of electromagnetic radiation emitted due to an electron making a transition from a high energy state to a lower energy state. The photon energy of the emitted photon is equal to the energy difference between the two states. There are many possible electron transitions for each atom, and each transition has a specific energy difference. This collection of different transitions, leading to different radiated wavelengths, make up an emission spectrum. Each element's emission spectrum is unique. Therefore, spectroscopy can be used to identify elements in matter of unknown composition. Similarly, the emission spectra of molecules can be used in chemical analysis of substances. Emission In physics, emission is the process by which a higher energy quantum mechanical state of a particle becomes converted to a lower one through the emission of a photon, resulting in the production of light. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Emissions Control (other) s
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Emissions control may refer to: * EMCON, military state of minimal radio emissions * Technology involved in vehicle emissions control * Regulation of air pollution via emission standard Emission standards are the legal requirements governing air pollutants released into the atmosphere. Emission standards set quantitative limits on the permissible amount of specific air pollutants that may be released from specific sources over ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exhalation
Exhalation (or expiration) is the flow of the breath out of an organism. In animals, it is the movement of air from the lungs out of the airways, to the external environment during breathing. This happens due to elastic properties of the lungs, as well as the internal intercostal muscles which lower the rib cage and decrease thoracic volume. As the thoracic diaphragm relaxes during exhalation it causes the tissue it has depressed to rise superiorly and put pressure on the lungs to expel the air. During forced exhalation, as when blowing out a candle, expiratory muscles including the abdominal muscles and internal intercostal muscles generate abdominal and thoracic pressure, which forces air out of the lungs. Exhaled air is 4% carbon dioxide, a waste product of cellular respiration during the production of energy, which is stored as ATP. Exhalation has a complementary relationship to inhalation which together make up the respiratory cycle of a breath. Exhalation and gas excha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Emission Coefficient
The emission spectrum of a chemical element or chemical compound is the spectrum of frequencies of electromagnetic radiation emitted due to an electron making a transition from a high energy state to a lower energy state. The photon energy of the emitted photon is equal to the energy difference between the two states. There are many possible electron transitions for each atom, and each transition has a specific energy difference. This collection of different transitions, leading to different radiated wavelengths, make up an emission spectrum. Each element's emission spectrum is unique. Therefore, spectroscopy can be used to identify elements in matter of unknown composition. Similarly, the emission spectra of molecules can be used in chemical analysis of substances. Emission In physics, emission is the process by which a higher energy quantum mechanical state of a particle becomes converted to a lower one through the emission of a photon, resulting in the production of light. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nocturnal Emission
A nocturnal emission, informally known as a wet dream, sex dream, nightfall or sleep orgasm, is a spontaneous orgasm during sleep that includes ejaculation for a male, or vaginal wetness or an orgasm (or both) for a female. Nocturnal emissions happen after stressful dreams in REM sleep which activate sympathetic nervous system hence leading to ejaculation.Nocturnal emissions are most common during adolescence and early young adult years, but they may happen any time after puberty. It is possible for men to wake up during a wet dream or simply to sleep through it, but for women, some researchers have added the requirement that she should also awaken during the orgasm and perceive that the orgasm happened before it counts as a wet dream. Vaginal lubrication alone does not mean that the woman has had an orgasm. Composition Due to the difficulty in collecting ejaculate produced during nocturnal emissions, relatively few studies have examined its composition. In the largest st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermionic Emission
Thermionic emission is the liberation of electrons from an electrode by virtue of its temperature (releasing of energy supplied by heat). This occurs because the thermal energy given to the charge carrier overcomes the work function of the material. The charge carriers can be electrons or ions, and in older literature are sometimes referred to as thermions. After emission, a charge that is equal in magnitude and opposite in sign to the total charge emitted is initially left behind in the emitting region. But if the emitter is connected to a battery, the charge left behind is neutralized by charge supplied by the battery as the emitted charge carriers move away from the emitter, and finally the emitter will be in the same state as it was before emission. The classical example of thermionic emission is that of electrons from a hot cathode into a vacuum (also known as thermal electron emission or the Edison effect) in a vacuum tube. The hot cathode can be a metal filament, a coate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Noise
Noise is unwanted sound considered unpleasant, loud or disruptive to hearing. From a physics standpoint, there is no distinction between noise and desired sound, as both are vibrations through a medium, such as air or water. The difference arises when the brain receives and perceives a sound. Acoustic noise is any sound in the acoustic domain, either deliberate (e.g., music or speech) or unintended. In contrast, noise in electronics may not be audible to the human ear and may require instruments for detection. In audio engineering, noise can refer to the unwanted residual electronic noise signal that gives rise to acoustic noise heard as a hiss. This signal noise is commonly measured using A-weighting or ITU-R 468 weighting. In experimental sciences, noise can refer to any random fluctuations of data that hinders perception of a signal. Measurement Sound is measured based on the amplitude and frequency of a sound wave. Amplitude measures how forceful the wave is. The e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
