1000 resultados para air accident


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In this paper, the analytical model coupling the convective boundary layer (CBL) with the free atmosphere developed by Qi and Fu (1992) is improved. And by this improved model, the interaction between airflow over a mountain and the CBL is further discussed. The conclusions demonstrate: (1) The perturbation potential temperatures in the free atmosphere can counteract the effect of orographic thermal forcing through entraining and mixing in the CBL. If u(M)BAR > u(F)BAR, the feedback of the perturbation potential temperatures in the free atmosphere is more important than orographic thermal forcing, which promotes the effect of interfacial waves. If u(M)BAR < u(F)BAR, orographic thermal forcing is more important, which makes the interfacial height and the topographic height identical in phase, and the horizontal speeds are a maximum at the top of the mountain. (2) The internal gravity waves propagating vertically in the free atmosphere cause a strong downslope wind to become established above the lee slope in the CBL and result in the hydraulic jump at the top of the CBL. (3) With the CBL deepening, the interfacial gravity waves induced by the potential temperature jump at the top of the CBL cause the airflow in the CBL to be subcritical.

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Presented in this paper is an experimental study on the characteristics of the turbulence produced by rising air bubbles in water. The measurements of turbulent velocities were made by using visualization technique of particle streak and computer image processing of the flow field. The turbulence features have been examined, showing that the rising bubble-produced turbulence can be approximately modeled by homogeneous turbulence as in the case of grid turbulence in air.

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Air flow at the land-sea-air interface influences to a large extent the atmospheric conditions that determine the transport, di lution, and trapping of natural and man-made air pollutants in the coastal areas of Monterey Bay and the Salinas Valley. Analysis of the hourly air flow on a daily and monthly basis indicates patterns of stagnation from midnight to noon of the fol lowing day with moderate to strong air flow during period 1300 to 2200. Throughout the year 1971 whenever flow is greater than 5 mph, the prevailing wind direction is onshore and from a westerly direction. Suggestions for urbanization and industrialization are made on the basis of an understanding of the atmospheric conditions which lead to trapping and dispersal of atmospheric waste. (27 page document)

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This report presents results of the first systematic study of the diversity and distribution of fishes and mussels in Avon Park Air Force Range (APR). We also provide information on crayfishes and aquatic snails taken during our fish and mussel sampling activities. Our surveys documented the presence of 46 species of fishes (43 native and 3 nonindigenous), 9 species of mussels (including 8 native and 1 nonindigenous species), 5 species of aquatic snails, and two crayfish species. (347 page document)