992 resultados para Final pressure
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Descreve os processos decisórios que levam à constituição de uma Comissão Parlamentar de Inquérito (CPI), bem como seus processos internos de decisão e produção do relatório final. A pesquisa foi feita com bases comparativas entre as CPIs e sua estrutura e os modelos de tomada de decisão e estrutura organizacional de Mintzberg.
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This paper describes the experimental and theoretical studies of gas-liquid bubbly flow in vertical upward pipeline carried out at Institute of Mechanics, Chinese Academy of Sciences. Bubbly flow in a vertical pipe with a 3 m long and 5 cm inner diameter plexiglass pipe was experimentally investigated, and studies carried out on the relationship between superficial velocities of the liquid and gas phases and pressure gradient is described. The developed drift-flux model applied to gas-liquid bubbly flow is presented, and the results are compared against the experimental data measured by ours in air/water vertical pipes.
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Experimentally observed, results are presented for the DCarcplasmajets and theirarc-rootbehaviors generated atreduced gas pressure and without or with an' applied magnetic field. Pure argon, argon -hydrogen or argon-nitrogen mixture is used as the plasma-forming gas. A specially designed copper mirror is constructed and used for better observing the arc-root behavior on the anode surface of the DC non-transferred arcplasma torch. It is shown that for the cases without applied magnetic field, the laminar plasmajets are stable and approximately axisymmetrical. The arc-root attachment on the anode surface is completely diffusive when argon is used as the plasma-forming gas, while the arc-root attachment often becomes constrictive when hydrogen or nitrogen is added into the argon. When an external magnetic field is applied, the arcroot tends to rotate along the anode surface of the non-transferred arcplasma torch.
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A new mathematical model for the transient flow in the composite low permeability is established. It is solved by FEM with different boundary conditions such as infinite, circular closed and constant pressure boundary conditions. The typical curves for transient wellbore pressure have been presented. It is shown that the pressure and pressure derivative curves with composite start-up pressure gradients have different slopes which are depended on the start-up pressure gradients and the mobility radios in different regions. The boundary effects are the same as the normal reservoirs without start-up pressure gradients. The study provides a new tool to analyze the transient pressure test data in the low permeability reservoir.
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Pressure wave refrigerators (PWR) refrigerate the gas through periodical expansion waves. Due to its simple structure and robustness, PWR may have many potential applications if the efficiency becomes competitive with existing alternative devices. In order to improve the efficiency, the characteristics of wave propagation in a PWR are studied by experiment, numerical simulation and theoretical analysis. Based on the experimental results and numerical simulation, a simplified model is suggested, which includes the assumptions of flux-equilibrium and conservation of the free energy. This allows the independent analysis of the operation parameters and design specifics. Furthermore, the optimum operation condition can be deduced. Some considerations to improve the PWR efficiency are also given.
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Rice cultivation at any level in the Sacramento–San Joaquin Delta (existing or expanded) compels the need to quantify surface and subsurface loads of dissolved organic carbon (DOC), disinfection byproduct precursors (DBPPs) and nitrogen. This information can be used to develop Best Management Practices (BMPs) to reduce export of these constituents in order to improve drinking water quality. Although rice cultivation in the Delta is relatively limited, several factors outside of this research could contribute to increased rice acreage in the Delta: • Recently developed rice varieties seem more suitable for the Delta climate than earlier varieties which required warmer conditions; • Previous economic analyses (Appendix A.10) suggest rice is more profitable than corn, a dominant land use in the Delta; • Recent studies on wetlands at Twitchell Island suggest rice production can help mitigate oxidative subsidence (Miller et al. 2000); • The different oxidative states that result from flooding in rice as compared to those found in crops that require drained soils may help control crop specific weeds and nematodes when rice is incorporated into a crop rotation; and • Providing flooded conditions during a greater part of the year than other crops may benefit water birds. ... (PDF contains 249 pages)
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Contact pressure of porous Al2O3 probed by nanoindentation was investigated by dimensional analysis with special attention paid to scaling effects in the mechanical behavior. It was found that, for sample containing small grains and interconnected pores, the contact pressure is manifest dominated by bonding strength of the porous alumina. Whereas the samples with coarse grain and various porous structures exhibit higher contact pressures and smaller residual deformations, which can be attributed to the mechanical response of the solid-phase under current limited peak loads.
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To be in compliance with the Endangered Species Act and the Marine Mammal Protection Act, the United States Department of the Navy is required to assess the potential environmental impacts of conducting at-sea training operations on sea turtles and marine mammals. Limited recent and area-specific density data of sea turtles and dolphins exist for many of the Navy’s operations areas (OPAREAs), including the Marine Corps Air Station (MCAS) Cherry Point OPAREA, which encompasses portions of Core and Pamlico Sounds, North Carolina. Aerial surveys were conducted to document the seasonal distribution and estimated density of sea turtles and dolphins within Core Sound and portions of Pamlico Sound, and coastal waters extending one mile offshore. Sea Surface Temperature (SST) data for each survey were extracted from 1.4 km/pixel resolution Advanced Very High Resolution Radiometer remote images. A total of 92 turtles and 1,625 dolphins were sighted during 41 aerial surveys, conducted from July 2004 to April 2006. In the spring (March – May; 7.9°C to 21.7°C mean SST), the majority of turtles sighted were along the coast, mainly from the northern Core Banks northward to Cape Hatteras. By the summer (June – Aug.; 25.2°C to 30.8°C mean SST), turtles were fairly evenly dispersed along the entire survey range of the coast and Pamlico Sound, with only a few sightings in Core Sound. In the autumn (Sept. – Nov.; 9.6°C to 29.6°C mean SST), the majority of turtles sighted were along the coast and in eastern Pamlico Sound; however, fewer turtles were observed along the coast than in the summer. No turtles were seen during the winter surveys (Dec. – Feb.; 7.6°C to 11.2°C mean SST). The estimated mean surface density of turtles was highest along the coast in the summer of 2005 (0.615 turtles/km², SE = 0.220). In Core and Pamlico Sounds the highest mean surface density occurred during the autumn of 2005 (0.016 turtles/km², SE = 0.009). The mean seasonal abundance estimates were always highest in the coastal region, except in the winter when turtles were not sighted in either region. For Pamlico Sound, surface densities were always greater in the eastern than western section. The range of mean temperatures at which turtles were sighted was 9.68°C to 30.82°C. The majority of turtles sighted were within water ≥ 11°C. Dolphins were observed within estuarine waters and along the coast year-round; however, there were some general seasonal movements. In particular, during the summer sightings decreased along the coast and dolphins were distributed throughout Core and Pamlico Sounds, while in the winter the majority of dolphins were located along the coast and in southeastern Pamlico Sound. Although relative numbers changed seasonally between these areas, the estimated mean surface density of dolphins was highest along the coast in the spring of 2006 (9.564 dolphins/km², SE = 5.571). In Core and Pamlico Sounds the highest mean surface density occurred during the autumn of 2004 (0.192 dolphins/km², SE = 0.066). The estimated mean surface density of dolphins was lowest along the coast in the summer of 2004 (0.461 dolphins/km², SE = 0.294). The estimated mean surface density of dolphins was lowest in Core and Pamlico Sounds in the summer of 2005 (0.024 dolphins/km², SE = 0.011). In Pamlico Sound, estimated surface densities were greater in the eastern section except in the autumn. Dolphins were sighted throughout the entire range of mean SST (7.60°C to 30.82°C), with a tendency towards fewer dolphins sighted as water temperatures increased. Based on the findings of this study, sea turtles are most likely to be encountered within the OPAREAs when SST is ≥ 11°C. Since sea turtle distributions are generally limited by water temperature, knowing the SST of a given area is a useful predictor of sea turtle presence. Since dolphins were observed within estuarine waters year-round and throughout the entire range of mean SST’s, they likely could be encountered in the OPAREAs any time of the year. Although our findings indicated the greatest number of dolphins to be present in the winter and the least in the summer, their movements also may be related to other factors such as the availability of prey. (PDF contains 28 pages)
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Experiments were conducted on copper subjected to High Pressure Torsion to investigate the evolution of microstructure and microhardness with shear strain, gamma. Observations have been carried out in the longitudinal section for a proper demonstration of the structure morphology. An elongated dislocation cell/subgrain structure was observed at relatively low strain level. With increasing strain, the elongated subgrains transformed into elongated grains and finally into equiaxed grains with high angle grain boundaries. Measurements showed the hardness increases with increasing gamma then tends to saturations when gamma >5. The variation tendency of microhardness with gamma can be simulated by Voce-type equation.