it has been proven through laboratory experiments that the three types of gas migration through a cemented annulus can be eliminated by designing the correct cement mixture. the first type of void and, therefore, gas migration can occur between the casing and the cement. by adding the correct amount of magnetite to the cement, this void, and therefore  the  possible  cause  of  gas migration, c...

Twenty two babies receiving artificial ventilator support were studied on 29 occasions to determine the effects of low levels of positive end expiratory pressure. Mean positive end expiratory pressure during these studies was 2.6 cm H2O. Changes in tidal volume, minute volume, compliance, and transcutaneous gas trends produced by the use of positive end expiratory pressure were investigated. Po...

Introduction: We aimed to study the effects of different CO2  pressures on expression of P33 gene and apoptosis in liver and spleen cells during CO2 pneumoperitoneum.  Methods: This study was performed on 30 male Sprague-Dawley rats, weighing between 280 and 340 g (procured from Tehran Pasteur Institute’s animal house). They were randomly divided into 3 equal groups. Groups 1 a...

The development and testing of hardware and software for a microprocessor-based monitoring system for gas turbines is described in this paper. The operators of gas turbines can be trained to monitor running hours, slip between high and low pressure compressor spools and torque on the reduction gear-box under various conditions of operation. The system will replace the traditional method of moni...

gas hydrates are a costly problem when they plug oil and gas pipelines. the best way to determine the hft and pressure is to measure these conditions experimentally for every gas system. since this is not practical in terms of time and money, correlations are the other alternative tools. there are a small number of correlations for specific gravity method to predict the hydrate formation. as th...

the volumetric changes in the coal matrix (coal shrinkage), permeability under various gas environment conditions as well as perographical properties were studied in the laboratory. the shrinkage and permeability of coal were examined with respect to changing gas type and confining pressures. the shrinkage tests were carried out in high-pressure bombs while the permeability study was conducted ...

While the threshold of splashing when liquid droplets impact against rigid solid surfaces is known to be related to the Weber number (We), the effect of ambient gas pressure (or density) and the impact angle have not been systematically studied. In this study, we examine the effects of droplet velocity, impact angle, and ambient gas pressure (or density) on the threshold of splashing. In our me...

It is well known that longer Bi-2212 conductors have significantly lower critical current density (Jc) than shorter ones, and recently it has become clear that a major cause of this reduction is internal gas pressure generated during heat treatment, which expands the wire diameter and dedensifies the Bi-2212 filaments. Here we report on the length-dependent expansion of 5 to 240 cm lengths of s...