Dust scattering

Appreciable penetration through clear atmosphere to sea level About About 7% 30% Penetration through clear atmosphere to sea level about 40% Dust scattering and absorption 2 km to sea level... 

Recent observations by Menard et al. (2002) of the intrinsic linear polarization of brown dwarfs show that dust scattering can take place immediately in the atmospheres of these objects. 

FIGURE 21 Far-UV spectra, obtained with lUE, of diffuse nebulae, (a) Orion nebula, a typical H II region, showing continuum due to dust scattering of UV starlight, with nebular emission lines. [Reprinted with permission from Torres-Peimbert, S., et al. (1980). Astrophys. J. 293, 133.] (b) Cygnus Loop, a supernova remnant, showing emission lines due to shock-heated gas. [Reprinted with permission from Raymond, J. C., et al. (1980). Astrophys. J. 238, 881.]... 

In the dense interstellar medium characteristic of sites of star fonuation, for example, scattering of visible/UV light by sub-micron-sized dust grains makes molecular clouds optically opaque and lowers their internal temperature to only a few tens of Kelvin. The thenual radiation from such objects therefore peaks in the FIR and only becomes optically thin at even longer wavelengths. Rotational motions of small molecules and rovibrational transitions of larger species and clusters thus provide, in many cases, the only or the most powerfiil probes of the dense, cold gas and dust of the interstellar medium. 

Water drops condensed in the atmosphere have much larger dimensions than gas molecules hence they are subject to the interference phenomena mentioned at the end of the last section. This alters the color of the scattered light. Smoke and dust particles are also larger and may absorb as well. 

The solutions must be carefully prepared so as to be free of dust particles and other extraneous scatterers. Filtration through sintered glass or centrifugation is widely used to clarify solutions of particles which would compete with polymeric solutes. This concern for cleanliness also extends to glassware, especially scattering cells. A fingerprint on the viewing window is disastrous ... 

The light-scattering objects must track the flow accurately, ensuring that their velocity represents the fluid velocity with a high accuracy. The light-scattering objects are either in the flow as a natural impurity such as dust, or are artificially introduced into the airflow at an optimum concentration ( seeding ). 

Lambert-Beer law The mathematical description of the attenuation of a light beam by absorption and scattering by dust particles in the airstream. 

Tyndall lamp A parallel light beam pro jected onto a cloud of dust particles gen crated from a process to produce scattering of the light, allowing an assessment of the magnitude and path of the cloud. 

The atmospheric attenuation factor takes into account the influence of absorption and scattering by water vapor, carbon dioxide, dust, and aerosol particles. One can assume, as a conservative position, a clear, dry atmosphere for which = 1. 

Streu-. scattering, scattered strewing dusting stray, -blau, n. powder blue, -brand-bombe, /. (Mil.) scatter bomb. 

Streudiise, /. spray nozzle, streuen, v.t. scatter strew spread disperse spray dust. 

Streuung, /. scattering dispersion strewing dusting spraying (Elec.) leakage deviation, variation. 

The entire observable universe, of which the Earth is a veiy tiny part, contains matter m the form of stars, planets, and other objects scattered in space, such as particles ol dust, molecules, protons, and electrons. In addition to containing matter, space also is filled with energy, part of it in the form of microwave radiation. 

A non-uegligible fraction of the solar radiation incident on the earth is lost by reflection from the top of the atmosphere and tops of clouds back into outer space. For the radiation penetrating the earth s atmosphere, some of the incident energy is lost due to scattering or absorption by air molecules, clouds, dust and aerosols. The radiation that reaches the earth s surface... 

Careful filtration of the solvent and of the polymer solution is essential in all light-scattering work. Traces of dust or dirt may introduce serious errors. 

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