- 産業: 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 ...
PM<sub>2. 5</sub> Aerosol particles that are smaller than or equal to 2. 5 micrometers or have an aerodynamic diameter of 2. 5 micrometers. In the Clean Air Act Revision of 1997 modified particulate standard to include PM<sub>2. 5</sub>. Considered fine particle matter, PM<sub>2. 5 </sub>has a greater effect of visibility and health than do larger aerosol particles, such as decreased lung function and premature death.
Industry:Chemistry; Weather
Point at which on the celestial sphere that the equator and the Ecliptic intersect. Generally the autumnal equinox occurs on or about September 23 in the northern hemisphere; this also signifies spring in the southern hemisphere.
Industry:Chemistry; Weather
Pollutants which are put into the atmosphere by stationary objects, such as refineries, power plants, mills, and the like. In Texas any source that emits more than one ton in a calendar year is considered a point source.
Industry:Chemistry; Weather
Pollution that occurs in cities from the burning of fossil fuels and the emissions of hydrocarbons. Urban air pollution can be in the form of ozone, smog, acid rain, carbon monoxide, particulate matter (PM-10), and nitrogen oxides.
Industry:Chemistry; Weather
Portion of the jet stream at which the winds reach a maximum velocity of 160 knots or more, the maximum winds within a jet stream.
Industry:Chemistry; Weather
Process by which up to 25% of radiant energy from the sun is reflected or scattered away from the surface by clouds. Serves the greatest importance in the atmospheric heat budget. Large errors in the assumed value of this variable may have important effects on computer models of the atmosphere.
Industry:Chemistry; Weather
Process by which, in a fluid being heated, the warmer part of the mass will rise and the cooler portions sink. This is also a a component of the theory for continental drift, in that the circulating movements of crustal materials push the continents apart.
Industry:Chemistry; Weather
Process in which heat energy is transported through a medium, usually a gas or liquid. An example, in the atmosphere occurs when warm air with a lower density experiences an upward force until it cools and its density matches the surrounding air, generally termed convection cells.
Industry:Chemistry; Weather
Process in which large chemical species break down into smaller, usually charged subunits, like a molecule breaking down into the ions that form it.
Industry:Chemistry; Weather
Processes by which particles of similar size and electrical characteristics separate or disperse different wavelengths (read colors) of light. First described by Gustav Mie in 1808. Since the sun's visible spectrum contains a mixture of (traditionally ordered) red, orange, yellow, green, blue, indigo, and violet colors, these wavelengths are differentially scattered by particles as they travel through the atmosphere. Red--longer wavelength--light is scattered not much and blue--shorted wavelength--light is scattered much more. This is why the sky appears blue: the sun's blue light is scattered back towards your eyes from atmospheric particles so when you look up--that is, away from the sun, the light you see is light scattered to your eye from atmospheric particles. (You might ask yourself why the sky--viewed at an off angle from the sun--isn't black instead of blue. ) Mie scattering is also the reason why sunsets appear red: the sun's red light is NOT scattered as much as blue light by atmospheric particles and so solar blue light is scattered away from your eyes on its way from the sun and red light is scattered less. The result is that more solar red light hits your eyes than blue and sunsets appear red. Notice also that the redness of sunsets increases at the amount of atmospheric particles between you and the sun increase, that is as the sun "goes down" mie scattering increases as the amount of particles between you and the sun increases.
Industry:Chemistry; Weather
