BACKGROUND The purpose of this study was to measure lumbar epidural pressure (EP) during the insertion of a Tuohy needle under general anesthesia and to evaluate the influence of airway pressure on EP. METHODS Lumbar EP was measured directly through a Tuohy needle during intermittent positive pressure ventilation in fifteen patients. Mean and peak EP were recorded after peak inspiratory press...

joule-thomson cooling systems are used in refrigeration processes such as cryogenic gas liquefaction. although extensive studies have been carried out by researchers, most of them include cryogenic heat exchangers and their associated fields. in the current study, an attempt was made to indicate the effect of using inappropriate operational conditions in a cryogenic joule-thomson cooling system...

A high pressure drop happens when heavy oil with high viscosity moves through the oil pipeline. A variety of methods to avoid this pressure drop is available. One of which is injection of chemicals to reduce the viscosity and ultimately reduce pressure drop. Using the pipesim software, the effect of dispersion of nano and micro-particles into the oil has been simulated to study the amount of th...

Energy gaps have been measured for the ferromagnetic quantum Hall effect states at ν = 1 and 3 in GaAs/Ga0.7Al0.3As heterojunctions as a function of Zeeman energy, which is reduced to zero by applying hydrostatic pressures of up to 20 kbar. At large Zeeman energy the gaps are consistent with spin-wave excitations. For a low-density sample the gap at ν = 1 decreases with increasing pressure and ...

in this paper, the effect of autofrettage process parameters on the ultimate pressure that functionally graded spherical vessel can tolerate are investigated. fgm properties and autofrettage pressure are considered as important parameters. assumptions are variation of properties of fgm in radial direction, the residual stress in the absence of bauschinger effect with the operation of variable m...

Introduction: Ramadan is a holy month for Muslims during which avoid from eating, drinking and sexual intercourse for about 13-17 hours. The aim of this study was surveying the effects of Islamic fasting in Ramadan on lipid profile and blood pressure.Materials and Methods: we designed this study in two phases, a week before and a week after Ramadan month. Eighty nine healthy subjects with 20-50...

the effect of γ-al2o3 nanoparticles on heat transfer rate, baffle spacing and pressure drop in the shell side of small shell and tube heat exchangers was investigated numerically under turbulent regime. γ-al2o3-water nanofluids and pure water were used in the shell side and the tube side of heat exchangers, respectively. since the properties of γ-al2o3-water nanofluids were variable, they were ...

purpose to investigate the effects of a 10-week water aerobic exercise on the resting blood pressure in patients with stage 1 or 2 hypertension referring to tehran university clinics. methods forty men with stage 1 or 2 essential hypertension were assigned to two groups of intervention [n = 12; aged 48.33±10.74 years (mean±sd)] and control [n = 28; aged 46.96±11.58 years (mean±sd)]. subjects in...