- Sektör: Education
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Founded in 1879 and named after Texas' greatest hero General Sam Houston, Sam Houston State University is public shcool within the Texas state university system and located in Huntsville, Texas.
It's a multicultural institution that offers 79 bachelorette degree programs, 54 masters and five ...
The spontaneous breakdown of certain kinds of atomic nuclei into one or more nuclei of different elements, involving the release of energy and subatomic particles such as neutrons.
Industry:Chemistry; Weather
This is a phenomenon that occurs during the polar winter in which stratospheric air moves in a circular motion, with a volume of relatively still air in its center. The temperature in the vortex is approximately -130 degrees F (-80 degrees C), which assists in the formation of polar stratospheric clouds. Though usually more prolonged and colder over Antarctica, the Arctic polar vortex does form to a degree, and when the temperatures there are coldest and the vortex persists, Arctic stratospheric ozone destruction on Arctic polar stratospheric clouds has also been observed.
Industry:Chemistry; Weather
The temperature at which air is cooled enough to reach its saturation point (100% humidity) for a given volume of water vapor in the air. If the air cooling occurs because of adiabatic expansion, clouds are formed; if it is due to contact of the air with a colder object, condensation (known as dew) is formed on the object; and if it is due to mixing of a warmer, moist air parcel with a cooler, dry parcel, fogs and condensation trails are created. Unlike humidity, the dewpoint is not based upon the temperature or pressure of the air, but solely upon the water vapor content. It can be measured using a dew point hygrometer, from the known temperature and relative humidity and by measuring the difference in wet and dry bulb temperatures. It is of importance in predicting fogs, frost, dew and overnight minimum temperatures.
Industry:Chemistry; Weather
This fuel consists mostly of hydrocarbons and is sometimes enhanced with benzene to increase octane ratings and is used as fuel in internal combustion engines. Unleaded gasoline is manufactured to meet the requirement of new model automobiles in the US since 1975, because in that year catalytic converters were made mandatory for all vehicles sold in the US. Lead was removed from gasoline because lead emissions poison the metals used in catalytic converters. Lead had been added to gasoline since the 1920's as tetraethyllead (TEL), historically referred to as "ethyl. " Exposure to high levels of lead can cause vomiting, diarrhea, convulsions, coma or even death, but lead emissions from automobiles consisted of lead oxide particles which settle out near highways. Lead removal from gasoline in the US has resulted in a clear, measurable decrease in lead in the urban environments in the US.
Industry:Chemistry; Weather
This may be a significant component of atmospheric aerosol particles that form from the atmospheric oxidation of dimethylsulfide (DMS), when this DMS is produced by phytoplankton. These aerosol particles can lead to the formation of cloud condensation nuclei, water droplet formation, and hence clouds and storm formation. This therefore may contribute to the turbulent mixing of oceanic surface waters and subsequent upwelling of nutrients that feed those microorganisms (a positive feedback cycle). It is thought that increased emissions of dimethylsulfide, and subsequent methanesulfonic acid over the oceans from an increase in sea water temperature may have a negative feedback on global warming by increasing cloud formation; although the net effect of clouds on global warming is very unclear at this point.
Industry:Chemistry; Weather
The speed of chemical reactions is expressed as a rate of change in the concentration of a participating species with respect to time. The reaction rates of chemical species in the atmosphere are extremely important parameters when considering sources and sinks of gas-phase components. For instance, the reaction rate for the reaction of hydroxyl radical with atmospheric propane in the troposphere is very fast, yielding an alkyl radical that goes through a series of reactions to yield ozone in urban environments. Conversely the reaction rate of propane with the nitrate radical ("NO<sub>3</sub> dot") is.
Industry:Chemistry; Weather
The relationship of the El Nino conditions and the Southern Oscillation pattern (The Walker Circulation). A high pressure over the Pacific Ocean and low pressure over the East Indies causes heavy rainfall across the Pacific, rise in the sea level and increased surface temperatures. .
Industry:Chemistry; Weather
This is a specific type of photolysis reaction, in which the destruction of a molecule is initiated strictly by solar energy.
Industry:Chemistry; Weather
To transport or carry. In air quality, the rate at which particulate matter is transported.
Industry:Chemistry; Weather
This refers to the types of pollutants that are either found in the atmosphere or on the ground and are emitted directly from some sources such as automobile tailpipes or smoke stacks. This is contrasted with secondary pollutants which in and of themselves are not directly emitted from a source. Instead they are created from chemical and photochemical reactions of primary pollutants. Nitrogen monoxide is an example of a primary pollutant and ozone is an example of a secondary pollutant.
Industry:Chemistry; Weather
