OBJECTIVE To discover design principles underlying the optimal waveforms for external chest and abdominal compression and decompression during cardiac arrest and cardiopulmonary resuscitation (CPR). METHOD A 14-compartment mathematical model of the human cardiopulmonary system is used to test successive generations of randomly mutated external compression waveforms during cardiac arrest and r...

Molecular dynamics simulation techniques and an analytic many-body potential function have been used to study a spherical C,,, cluster (“Buckminsterfullerene”) compressed between graphite planes. We find that the cluster can reversibly deform under anisotropic compression to a radius (in the direction of compression) that is l/3 that of the uncompressed cluster. On compression the restoring pre...

The effect of squeeze casting process parameters on wear behavior of AC2A aluminium alloy was primarily investigated in this experimental study. Five process parameters, namely squeeze pressure, pouring temperature, die temperature, die material and compression time, each at four levels were chosen and sixteen experimental runs based on L16 orthogonal array were performed. From analysis of vari...

Buckling of imperfect thin shell tank which is subjected to uniform axial compression is analyzed. The effect of internal pressure on the stability of a shell tank filled with a homogeneous-heterogeneous liquid was considered. Investigation of the liquid nature effect on reduction of the shell buckling load is performed by using the finite elements method. Calculating results in terms of analyt...

The effect on elastic stockings on ambulatory venous pressure was investigated in 22 limbs with deep venous insufficiency. The failure of some elastic stockings to reduce the ambulatory venous pressure in some limbs is due to the lack of graduated compression, which is caused by ankle-calf disproportion--narrow ankles and wide calves. This can be recognised by using the pressure-girth profile a...

the pressure drop of refrigerant r-134a flow boiling inside a horizontal tube has been investigated experimentally. the test set-up which was used in this investigation is a well instrumented vapor compression refrigeration system. these instruments are thermocouples, flow meter, pressure gauges and the pressure drop measuring apparatus. this system consisted of three electrically heated evapor...

The aim of this study was to establish a pressure ulcer model that visualizes the microcirculation, and to examine the participation of ischemia-reperfusion injury in the pathophysiology of pressure ulcers. An original system composed of a new skin fold chamber and compression device allowed loading quantitative vertical stress to the skin. An intravital microscopic technique enabled direct vis...