نتایج جستجو برای: ambient atmosphere
تعداد نتایج: 103116 فیلتر نتایج به سال:
The formation of negative ions produced in a negative point-to-plane corona discharge fed by a Ar/N2/CH4 gas mixture has been studied using mass spectrometry. The measurements were carried out in flowing regime at ambient temperature and a reduced pressure of 460 mbar. The CN− anion has been found to be the most dominant negative ion in the discharge and is believed to be the precursor of heavi...
The oxygen exchange activity of mixed conducting oxide surfaces has been widely investigated, but a detailed understanding of the corresponding reaction mechanisms and the rate-limiting steps is largely still missing. Combined in situ investigation of electrochemically polarized model electrode surfaces under realistic temperature and pressure conditions by near-ambient pressure (NAP) XPS and i...
The magnitude of aerosol radiative forcing caused by anthropogenic emissions depends on the baseline state of the atmosphere under pristine preindustrial conditions. Measurements show that particle formation in atmospheric conditions can occur solely from biogenic vapors. Here, we evaluate the potential effect of this source of particles on preindustrial cloud condensation nuclei (CCN) concentr...
The concentrations of five hazardous air pollutants were simulated using the community multi-scale air quality (CMAQ) modeling system. Annual simulations were performed over the continental United States for the entire year of 2001 to support human exposure estimates. Results are shown for formaldehyde, acetaldehyde, benzene, 1,3-butadiene and acrolein. Photochemical production in the atmospher...
Charge-exchange reactions at high energies provide new channels for the remote sensing of solar high-energy particles, as demonstrated by the recent detection of 1.8-5 MeV hydrogen atoms from a solar flare [1]. Orrall and Zirker [2] had earlier proposed the detection of low-energy protons via charge-exchange atomic reactions in the solar atmosphere, leading in the simplest case to extended red-...
background: the variation of the radon progeny concentration in outdoor environment and meteorological parameters at fine resolution were studied for one year at a continental location, national atmospheric research laboratory, gadanki, india. materials and methods: the concentrations were measured using alpha progeny meter by collecting air samples at a height of 1 m above the earth’s surface...
Air Pollution is one of the significant problems in Tehran. Understanding the role of different sources can result in better decision-making. Some pollutions are not emitted directly from sources and are present in the atmosphere due to chemical reactions. Therefore, using air quality modeling can be beneficial to our understanding of these phenomena. An air quality modeling system was used fir...
Atmospheric halothane was sampled from three selected operating theatres and anaesthetic rooms during the middle of operating sessions. Two of the operating theatres studied were ventilated with total air exchange once every six minutes; the third operating theatre had no ventilation. End-tidal samples were obtained from anaesthetists. Halothane vapour concentrations were analysed by gas-liquid...
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