The Ranque–Hilsch vortex tube splits a single high pressure stream of gas into cold and warm streams. Simple models for the vortex tube combined with regenerative precooling are given from which an optimization can be undertaken. Two such optimizations are needed: the first shows that at any given cut or fraction of the cold stream, the best refrigerative load, allowing for the temperature lift...

A wind tunnel investigation was performed to study the flow field over a 70° swept sharped edge delta wing model at high angles of attack. The experiments were conducted in the subsonic wind tunnel at the Department of Mechanical Engineering, Sharif University of Technology. Velocity profiles have been measured using a special pitot tube and hot wire anemometer at angles of attacks of 10 to 35 ...

By controlling the traction between its body and the tube wall, a tube-dwelling polychaete can move efficiently from one end of its tube to the other, brace its body during normal functions (e.g., ventilation and feeding), and anchor within its tube avoiding removal by predators. To examine the potential physical interaction between worms and the tubes they live in, scanning electron microscopy...

A theory was developed that explains energy separation in a vortex tube, known as one of the Maxwellian demons. It appears that there is a unique relation between the pressures in the exits of the vortex tube and its temperatures. Experimental results show that the computed and measured temperatures are in very good agreement.

A wind tunnel investigation was performed to study the flow field over a 70° swept sharped edge delta wing model at high angles of attack. The experiments were conducted in the subsonic wind tunnel at the Department of Mechanical Engineering, Sharif University of Technology. Velocity profiles have been measured using a special pitot tube and hot wire anemometer at angles of attacks of 10 to 35 ...

The Delves micro-scale technique for blood lead analysis is an accurate method for screening capillary blood specimens, obtained by fingerstick, for lead intoxication. Results are affected by the age of cup, loop, and hollow-cathode tube and by the spatial relationship between optical tube and cup. Because the glass in many commercially available capillary tubes (used in specimen collection) ...

Very reliable methods have been developed to extract RNA from different tissues and cell lines (1, 2, 3). RNA preparation, however, is still cumbersome and time consuming, especially when extracting a large number of cells (>10) and cell samples. The isolation of RNA from leucocytic cells is particularly difficult for three reasons: a) high levels of endogenous RNase; b) low amount of RNA (RNA/...