The height of the water flowing fractured zone (HWFFZ) is key parameter for safe coal mining under bodies. In order to improve accuracy prediction model HWFFZ, grey relational analysis (GRA) used quantitatively analyze influencing factors main HWFFZ condition comprehensive mechanized and top caving are selected scientifically, these five that include depth, thickness, inclined length working fa...

At dip equatorial stations in the Indian zone, spread-F conditions are known to develop preferentially around midnight during the June solstice (northern summer) months of low solar activity, in association with a distinct increase in F layer height. It is currently held that this onset of spread-F far away from the sunset terminator is due to the generalised Rayleigh-Taylor instability mechani...

Kongzhuang coal mine of Shanghai Datun Energy Resources Co., Ltd. is a typical deep in eastern China. The mining disturbance working face leads to the fracture and movement overlying strata damage aquifer strata, thereby causing water inrush disaster posing serious threat safety production mine. Therefore, temporal spatial evolution mechanism water-conducting fractured zone researched systemati...

The migration of methane towards the surface, within mining areas closed mines, can be a danger to public safety for many years after process liquidation has been finished. liberation from undisturbed coal seams, and those destressed through earlier not fully recognised so far. Knowledge effect presence water, along with hydrostatic pressure, on intensity desorption seams is necessary in determ...

OBJECTIVE The aim of this study was to investigate whether a secular trend in growth occurred during the last century in Pygmies from Cameroon (West Pygmies) and in Bantu rural farmers, the latter being studied to serve as controls. DESIGN The evolution in height of West Pygmies and Bantu farmers from 1911 to 2006 was evaluated using data from the literature as well as data gathered by our re...

through this article, the distribution of air pollutants in tehran have been simulated based on wind patterns with and without the presence of synoptic by tapm (a meso-scale model). the simulation covers three horizontal resolution domains 30, 15 and 5 kilometers. the pollutants chosen for this are co and pm10 and wind data is 10 meter height level. the result has shown that the model simulated...

Using numerical MHD simulations, we have studied the evolution of the magnetorotational instability in stratified accretion disks in which the ionization fraction (and therefore resistivity) varies substantially with height. This model is appropriate to dense, cold disks around protostars or dwarf nova systems which are ionized by external irradiation of cosmic rays or high-energy photons. We f...

Semidiurnal solar tides in the mid-latitude troposphere are investigated using harmonic analysis of 404 MHz radar profiler wind data obtained from a wide longitude zone in the U.S. The tides are apparent above a 1000-m-deep surface layer and increase in amplitude with height, attaining speeds of 0.5-0.7 rn/s at 5-7 km. Observed wind characteristics agree well with tidal characteristics obtained...