- 行业: 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 plane of orbit of the earth around the sun. An animation showing this process is available on its own page.
Industry:Chemistry; Weather
This is the average level of the ocean over the entire earth. Tidal fluctuation is taken into account when determining sea level. Mean Sea Level (MSL) is used to reference the height of structures above ground level and depth below the ocean's surface. Atmospheric pressure is also referenced from sea level. At sea level, 760mm (29. 92 inches) of mercury is normally displaced by the pressure of the air column above that point on the earth.
Industry:Chemistry; Weather
The science of heat and temperature and of the laws governing the conversion of heat into mechanical, electrical, or chemical energy.
Industry:Chemistry; Weather
These terms give scientists a way to describe how much of a substance is contained in a sample: parts of analyte per million parts of sample, for instance. In atmospheric chemistry these become volume parts of analyte per volume parts of atmosphere: ppmv, ppbv, etc. At low analyte gas phase concentrations the analyte is assumed to act as an ideal gas. For instance, a 1 ppmv concentration of formaldehyde would represent 1 liter of formaldehyde per every 1,000,000 liters of air; also equivalent to 1 microliter of H<sub>2</sub>CO per 1 L air. In gas phase concentrations these units are also called gas phase mixing ratios. The reason is because they are just that, ratios of analyte volume to sample volume; the volume of the sample doesn't matter.
Industry:Chemistry; Weather
This is a removal process for chemicals in the atmosphere such as dissolution in bodies of water, removal via rain, photolysis, or by reactions with other atmospheric components. For instance, because of high chemical stability, the major atmospheric sink for the chlorofluorcarbon CCl<sub>3</sub>F is photolysis in the upper atmosphere. In the troposphere this compound is extremely long-lived because it isn't very water soluble, doesn't react with other tropospheric components, and isn't microbially attacked in soils or by plants.
Industry:Chemistry; Weather
The process of the removal of atmospheric constituents by precipitation. One item necessary for a rain drop to form is a condensation nucleus. Pollutants in the air such as nitric acid and sulfuric acid form nucleation sites (particles) upon which water vapor often condenses and forms a droplet. As these droplets grow they collect more moisture and may ultimately fall out as precipitation. This accounts for some of the acid rain deposition on the planet's surface and a means by which atmospheric aerosols, gases, and particles are removed.
Industry:Chemistry; Weather
This is the process in which energy from heat is released into the atmosphere through conduction and convection, as contrasted by latent heat, released by the condensation of water vapor. Atmospheric circulation can then move the heat (energy) horizontally.
Industry:Chemistry; Weather
This is a derived formula, from the German physicist Max Planck, that portrays the amount of radiation emitted by a blackbody as theoretically determined by its temperature. It is an equation that produces a curve, termed Planck's blackbody radiation curve, which illustrates that the warmer a body is, the greater is its blackbody emission at each wavelength and the shorter is the wavelength at which emissions peak.
Industry:Chemistry; Weather
The ratio of absolute viscosity--or a fluid's resistance to flow--to the density of that fluid; this is commonly measured by determining the time it takes a liquid to travel through a capillary under the influence of gravity, using an instrument called a capillary viscometer, and can be expressed in units of m<sup>2</sup> per s. The atmosphere's kinematic viscosity changes with altitude and this affects the rates at which gases exchange between layers. In general, the atmosphere's viscosity is higher at higher altitudes.
Industry:Chemistry; Weather
The sum total of all the gases surrounding the Earth, extending several hundred kilometers above the surface in a mechanical mixture of various gases in fluid-like motion. The permanent constituents are molecular nitrogen; 78. 1%, molecular oxygen; 20. 9%, argon; 0. 934%, and approximately 0. 037% carbon dioxide (but this is increasing. . . ). Various other components exist in trace amounts. Not to be under emphasized, these trace components are where the interesting atmospheric chemistry occurs. The atmosphere can also be artificially divided into layers. Example: the troposphere (the layer closest to the earth) and the stratosphere (the layer above the troposphere).
Industry:Chemistry; Weather
