Direct numerical simulations (DNS) are carried out to investigate the effect of effu-sion cooling by blowing through spanwise slits and discrete holes in a laminar flat-plate boundary layer at various Mach numbers. The comparison with experimental data for a Mach-2.67 boundary layer with a cool wall and a spanwise slit shows good agreement. For an adiabatic Mach-6 boundary layer, the focus of t...

We discuss the implications of new relations between black holes’ masses, Xray luminosities and radio luminosities, as well as the properties of the next generation of radio telescopes, for the goal of finding isolated accreting black holes. Because accreting black holes have radio-to-X-ray flux ratios that increase with decreasing luminosity in Eddington units, and because deep surveys over la...

We present case examples of foreshock density holes and results from a statistical survey, which provide additional characterizations of these recently-described structures. Specific effort is made to place these objects into context with well-studied foreshock phenomena, such as hot flow anomalies (HFAs) and large-amplitude magnetic pulsations (SLAMS). Density holes are observed during highert...

The present work aims at reducing the friction of rubber soles sliding on ceramic floorings. Fitting bored cylindrical protrusions with different diameters on rubber soles was proposed. Experiments were carried out to evaluate the performance of the proposed protrusions in increasing friction coefficient at dry and contaminated floorings. It was found that, at dry sliding, friction coefficient ...

two polygonal biogenic sedimentary rare structures of koilosoma (hitchcock 1858) have been found due to neoichnology of the abhar-rud river fluvial sediments, northwest iran. one of them is polygon holes, with about one square meter area. polygons are same in size and depth, and are hexagonal in shape. they have distinct boundaries like the honeycomb. this sample is like the reported specimens ...