The Experts below are selected from a list of 60 Experts worldwide ranked by ideXlab platform
Duncan A - One of the best experts on this subject based on the ideXlab platform.
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Estimation of Leak Rate from the Emergency Pump Well in L-Area Complex Basin
Savannah River Site (S.C.), 2005Co-Authors: Duncan AAbstract:This report provides an estimate of the leak rate from the Emergency Pump well in L-basin that is to be expected during an off-normal event. This estimate is based on expected shrinkage of the engineered grout (i.e., controlled low strength material) used to fill the Emergency Pump well and the header pipes that provide the dominant leak path from the basin to the lower levels of the L-Area Complex. The estimate will be used to provide input into the operating safety basis to ensure that the water level in the basin will remain above a certain minimum level. The minimum basin water level is specified to ensure adequate shielding for personnel and maintain the ''as low as reasonably achievable'' concept of radiological exposure. The need for the leak rate estimation is the existence of a gap between the fill material and the header pipes, which penetrate the basin wall and would be the primary leak path in the event of a breach in those pipes. The gap between the pipe and fill material was estimated based on a full scale demonstration pour that was performed and examined. Leak tests were performed on full scale pipes as a part of this examination. Leak rates were measured to be on the order of 0.01 gallons/minute for completely filled pipe (vertically positioned) and 0.25 gallons/minute for partially filled pipe (horizontally positioned). This measurement was for water at 16 feet head pressure and with minimal corrosion or biofilm present. The effect of the grout fill on the inside surface biofilm of the pipes is the subject of a previous memorandum
A Duncan - One of the best experts on this subject based on the ideXlab platform.
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Estimation of Leak Rate from the Emergency Pump Well in L-Area Complex Basin
2005Co-Authors: A DuncanAbstract:This report provides an estimate of the leak rate from the Emergency Pump well in L-basin that is to be expected during an off-normal event. This estimate is based on expected shrinkage of the engineered grout (i.e., controlled low strength material) used to fill the Emergency Pump well and the header pipes that provide the dominant leak path from the basin to the lower levels of the L-Area Complex. The estimate will be used to provide input into the operating safety basis to ensure that the water level in the basin will remain above a certain minimum level. The minimum basin water level is specified to ensure adequate shielding for personnel and maintain the ''as low as reasonably achievable'' concept of radiological exposure. The need for the leak rate estimation is the existence of a gap between the fill material and the header pipes, which penetrate the basin wall and would be the primary leak path in the event of a breach in those pipes. The gap between the pipe and fill material was estimated based on a full scale demonstration pour that was performed and examined. Leak tests were performed on full scale pipes as a part of thismore » examination. Leak rates were measured to be on the order of 0.01 gallons/minute for completely filled pipe (vertically positioned) and 0.25 gallons/minute for partially filled pipe (horizontally positioned). This measurement was for water at 16 feet head pressure and with minimal corrosion or biofilm present. The effect of the grout fill on the inside surface biofilm of the pipes is the subject of a previous memorandum.« less
James B. Young - One of the best experts on this subject based on the ideXlab platform.
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One hundred patients with the HeartMate left ventricular assist device: evolving concepts and technology
The Journal of Thoracic and Cardiovascular Surgery, 1998Co-Authors: Patrick M. Mccarthy, Nicholas Smedira, Rita L. Vargo, Marlene Goormastic, Robert E. Hobbs, Randall C. Starling, James B. YoungAbstract:Abstract Background: Implantable left ventricular assist devices are common as a bridge to transplantation but are just reaching their goal as an alternative to transplantation. Methods: From December 1991 until December 1996, 97 left ventricular assist devices were implanted as a bridge to transplantation, one as an alternative to transplantation, and two as a bridge to recovery. Included were 64 pneumatic devices and 36 electric devices. Most patients (69%) had ischemic cardiomyopathy and most (53%) had had previous cardiac surgery. Preoperative circulatory support (extracorporeal membrane oxygenation) was used in 25. Results: Perioperative insertion of a right ventricular assist device was unusual (11%). The mean duration of support with a left ventricular assist device (bridge to transplantation) was 70 ± 41 days (up to 206 days). Survival to transplantation was 76%. Cause of death included multiple organ failure ( n = 13), perioperative stroke ( n = 5), device failure ( n = 5), and controller disconnect ( n = 1). Significant risk factors for death included (1) preoperative need for ventilator or extracorporeal membrane oxygenation, (2) elevated blood urea nitrogen, creatinine, or bilirubin, and (3) low pulmonary artery pressures. Risks after insertion of the left ventricular assist device were reoperation for bleeding, support with a right ventricular assist device, dialysis, or device failure. Catastrophic failure of the device occurred 14 times in 12 patients and was treated by Emergency Pump exchange in six instances. Only two device-related thromboembolic episodes were detected. Positive blood cultures were found in 59% of patients, driveline infection in 28%, and Pump infection in 11%. Conclusions: The HeartMate device provided excellent hemodynamic support with low device-related thromboembolic events. Infection and reliability of the device contributed to the high cost of therapy. These areas need to be improved for the left ventricular assist device to attain its goal as a viable alternative to transplantation. (J Thorac Cardiovasc Surg 1998;115:904-12)
Andrews G - One of the best experts on this subject based on the ideXlab platform.
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Experimental investigation of potential confined ignition sources for vapour cloud explosions
2019Co-Authors: Gill J, Atkinson G, Cowpe E, Phylaktou H, Andrews GAbstract:Electrical control boxes are prolific on high vapour cloud hazard sites, and in the case of the Buncefield explosion the ignition source was inside such a box that was sited in an Emergency Pump house building. There has, however, been relatively little previous research into this type of ignition mechanism and its effect on the explosion severity. Commercially available electrical control boxes measuring 600 mm high, 400 mm wide and 250 mm deep were used to explore the pressure development, venting processes and flame characteristics of stoichiometric propane/air explosions using aluminium foil and the supplied doors as vent coverings. In this work, the boxes were empty of their usual contents in order to establish a baseline for the effect of the internal congestion of the boxes. It was found that, in these empty-box tests, the door produced a flat petal shaped flame, which differed drastically from the mushroom flame shape, associated rolling vortex bubble venting traditionally observed with large orifice vented explosions
Gordon E. Andrews - One of the best experts on this subject based on the ideXlab platform.
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Experimental investigation of potential confined ignition sources for vapour cloud explosions
Process Safety and Environmental Protection, 2020Co-Authors: Jason Gill, Graham T. Atkinson, Edmund Cowpe, Herodotos N. Phylaktou, Gordon E. AndrewsAbstract:Abstract Electrical control boxes are common on high vapour cloud hazard sites, and in the case of the Buncefield explosion the ignition source was inside such a box, that was sited in an Emergency Pump house building. There has, however, been relatively little previous research into this type of ignition mechanism and its effect on the explosion severity. Commercially available electrical control boxes measuring 600 mm high, 400 mm wide and 250 mm deep were used to explore the pressure development, venting processes and flame characteristics of stoichiometric propane/air explosions using aluminium foil and the supplied doors as vent coverings. In some tests, the boxes were empty in order to establish a baseline for the effect of the internal congestion of the boxes. In other tests a congestion array was added. It was found that, in both the empty and congested box tests, the door produced a flat petal shaped flame, which differed drastically from the mushroom flame shape and associated rolling vortex bubble venting that is traditionally observed with large orifice vented explosions.