摘要 :
A fully coupled dual-porosity model is developed and used to simulate a given field condition. History match from ten wells in Northwest China shows a significant and sustained production decline, despite a continuous increase in ...
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A fully coupled dual-porosity model is developed and used to simulate a given field condition. History match from ten wells in Northwest China shows a significant and sustained production decline, despite a continuous increase in drawdown. A critical drawdown is identified, after which the drawdown increase effect is neutralized from that from the permeability reduction. A different drawdown increase strategy by maintaining a constant bottom hole pressure (BHP), yet increasing the far-field reservoir pressure is proposed and applied. This way the drawdown can be increased without reducing the near wellbore permeability. Production decline can be stopped and reversed. Simulations on the field indicate that more than 30% production rate increase can be expected from each well, depending on the in-situ stress level against the permeability changes in the formation. Identifying these critical drawdowns is also economically important, as ineffective drawdown increase can generate zero or negative incremental production, at extra cost.
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摘要 :
Hollow fiber membranes, with a high packing density and an easy assembly in bundles and
modules, are one of the most cost competitive solutions for water membrane filtration, re-use
of wastewater, or prefiltration before Reverse O...
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Hollow fiber membranes, with a high packing density and an easy assembly in bundles and
modules, are one of the most cost competitive solutions for water membrane filtration, re-use
of wastewater, or prefiltration before Reverse Osmosis. Over the years, the investment and
maintenance costs of such membrane systems have dramatically decreased and are now
cost competitive with the conventional media filters. This was possible thanks to both module
design evolution and associated process improvements. However, since the size of standard
modules are today relatively small (from 4 to 12 inches), huge number of modules and huge
number of associated connections, pipes and modules supports are necessary for the
construction of large plants. It is a drawback for cost reduction which has reached a plateau.
A way, to start again costs saving, is to pass to larger pressurized module diameter. In this
paper, a new and unique very large pressurized hollow fiber membranes module, developed
recently by Polymem, is presented.The module, named Gigamem~? UF240, with 600 mm
diameter (24 inches) and 1.5 m height (60 inches), develops at least 540 m2 of membrane
filtration area. The module is set directly on the ground, eliminating the need of module
supports. Furthermore, since the inlet of raw water and the outlet of treated water are both
located at the top of the module, only two headers located at the top, are needed. Hollow
fibers are gathered in individual bundles which facilitates the maintenance of the
membranes: removal of fiber elements, fiber integrity check and membrane replacement.
During membrane replacement, only the fiber elements will be replaced thus saving the cost
of module vessels replacement. These design improvements allow significant reductions in
both investment and operating costs.
Hydraulic and rejection studies achieved on the Gigamem~? module are presented. Permeate
turbidity was always lower than 0.1 NTU. Virus and bacteria rejections up to 7 log were
achieved for UF membranes.
Fields of application are drinking water production, pre-treatment to seawater desalination by
reverse osmosis and tertiary filtration of municipal and industrial wastewaters. Several full
size plants are constructed or under construction based on Gigamem~? modules.
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摘要 :
Hollow fiber membranes, with a high packing density and an easy assembly in bundles and
modules, are one of the most cost competitive solutions for water membrane filtration, re-use
of wastewater, or prefiltration before Reverse...
展开
Hollow fiber membranes, with a high packing density and an easy assembly in bundles and
modules, are one of the most cost competitive solutions for water membrane filtration, re-use
of wastewater, or prefiltration before Reverse Osmosis. Over the years, the investment and
maintenance costs of such membrane systems have dramatically decreased and are now
cost competitive with the conventional media filters. This was possible thanks to both module
design evolution and associated process improvements. However, since the size of standard
modules are today relatively small (from 4 to 12 inches), huge number of modules and huge
number of associated connections, pipes and modules supports are necessary for the
construction of large plants. It is a drawback for cost reduction which has reached a plateau.
A way, to start again costs saving, is to pass to larger pressurized module diameter. In this
paper, a new and unique very large pressurized hollow fiber membranes module, developed
recently by Polymem, is presented.The module, named Gigamem~? UF240, with 600 mm
diameter (24 inches) and 1.5 m height (60 inches), develops at least 540 m2 of membrane
filtration area. The module is set directly on the ground, eliminating the need of module
supports. Furthermore, since the inlet of raw water and the outlet of treated water are both
located at the top of the module, only two headers located at the top, are needed. Hollow
fibers are gathered in individual bundles which facilitates the maintenance of the
membranes: removal of fiber elements, fiber integrity check and membrane replacement.
During membrane replacement, only the fiber elements will be replaced thus saving the cost
of module vessels replacement. These design improvements allow significant reductions in
both investment and operating costs.
Hydraulic and rejection studies achieved on the Gigamem~? module are presented. Permeate
turbidity was always lower than 0.1 NTU. Virus and bacteria rejections up to 7 log were
achieved for UF membranes.
Fields of application are drinking water production, pre-treatment to seawater desalination by
reverse osmosis and tertiary filtration of municipal and industrial wastewaters. Several full
size plants are constructed or under construction based on Gigamem~? modules.
收起
摘要 :
Hollow fiber membranes, with a high packing density and an easy assembly in bundles and modules, are one of the most cost competitive solutions for water membrane filtration, re-use of wastewater, or prefiltration before Reverse O...
展开
Hollow fiber membranes, with a high packing density and an easy assembly in bundles and modules, are one of the most cost competitive solutions for water membrane filtration, re-use of wastewater, or prefiltration before Reverse Osmosis. Over the years, the investment and maintenance costs of such membrane systems have dramatically decreased and are now cost competitive with the conventional media filters. This was possible thanks to both module design evolution and associated process improvements. However, since the size of standard modules are today relatively small (from 4 to 12 inches), huge number of modules and huge number of associated connections, pipes and modules supports are necessary for the construction of large plants. It is a drawback for cost reduction which has reached a plateau. A way, to start again costs saving, is to pass to larger pressurized module diameter. In this paper, a new and unique very large pressurized hollow fiber membranes module, developed recently by Polymem, is presented.The module, named Gigamem? UF240, with 600 mm diameter (24 inches) and 1.5 m height (60 inches), develops at least 540 m~2 of membrane filtration area. The module is set directly on the ground, eliminating the need of module supports. Furthermore, since the inlet of raw water and the outlet of treated water are both located at the top of the module, only two headers located at the top, are needed. Hollow fibers are gathered in individual bundles which facilitates the maintenance of the membranes: removal of fiber elements, fiber integrity check and membrane replacement. During membrane replacement, only the fiber elements will be replaced thus saving the cost of module vessels replacement. These design improvements allow significant reductions in both investment and operating costs. Hydraulic and rejection studies achieved on the Gigamem? module are presented. Permeate turbidity was always lower than 0.1 NTU. Virus and bacteria rejections up to 7 log were achieved for UF membranes. Fields of application are drinking water production, pre-treatment to seawater desalination by reverse osmosis and tertiary filtration of municipal and industrial wastewaters. Several full size plants are constructed or under construction based on Gigamem? modules.
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摘要 :
Vehicle emission have negative effects on human health. City residents will consider the risks which traffic pollution posts to the personal health when making travel choices. The survey in this paper demonstrates that non-motoris...
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Vehicle emission have negative effects on human health. City residents will consider the risks which traffic pollution posts to the personal health when making travel choices. The survey in this paper demonstrates that non-motorists may take actions to reduce their exposure to transportation-related emission. To evaluate this effect, the disutility of vehicle emission based on the cost function of discrete choice model is introduced, and a new definition of the extra time that cyclists would spend in changing traffic modes or routes to reduce their exposure to emission is proposed. A network assignment model with regards of the disutility of vehicle emission and a solution procedure are established. Finally, a numerical example is provided to compare the difference between the bicycle network assignment with the consideration of the disutility of vehicle emission or without this consideration.
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摘要 :
Vehicle emission have negative effects on human health. City residents will consider the risks which traffic pollution posts to the personal health when making travel choices. The survey in this paper demonstrates that non-motoris...
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Vehicle emission have negative effects on human health. City residents will consider the risks which traffic pollution posts to the personal health when making travel choices. The survey in this paper demonstrates that non-motorists may take actions to reduce their exposure to transportation-related emission. To evaluate this effect, the disutility of vehicle emission based on the cost function of discrete choice model is introduced, and a new definition of the extra time that cyclists would spend in changing traffic modes or routes to reduce their exposure to emission is proposed. A network assignment model with regards of the disutility of vehicle emission and a solution procedure are established. Finally, a numerical example is provided to compare the difference between the bicycle network assignment with the consideration of the disutility of vehicle emission or without this consideration.
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Offshore outsourcing of software development has been both famous for the promises of great cost reductions, and infamous for the hidden costs associated with the challenges of organizing software work over distance. Experience sh...
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Offshore outsourcing of software development has been both famous for the promises of great cost reductions, and infamous for the hidden costs associated with the challenges of organizing software work over distance. Experience shows that many of these costs do not receive the deserved attention and are often excluded when making offshoring decisions. As a result, there is often a significant deviation between the expected and the realized costs of offshoring. In this paper, we investigate the awareness of the extra costs when making an offshoring decision, and the significance of the actual cost deviations. We conducted a single case study of a company that carried out an offshore outsourcing pilot project. We collected qualitative data from interviews, observations and a retrospective, and quantitative data on the costs and effort associated with the project. We conclude that the company was aware of the hidden cost factors, but largely underestimated their significance. The costs that surfaced in the studied project accounted for a total deviation of 181% and several individual cost categories with more than 400% overrun. The two main cost drivers in our study were the distance and poor process fit, which escalated the investments needed to make the collaboration work. Our results suggest that pilots are useful to understand the key problem areas in an offshoring collaboration, but too limited to shed light on all potential problems (e.g. turnover) due to the short timeframe. We also conclude that results of pilot projects shall not be the only data source when calculating the true costs of offshoring, since the start-up phase of an offshoring relationship carries large investments. Finally, we provide recommendations for companies in a similar situation on how to run and learn from offshore outsourcing pilot projects.
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摘要 :
Offshore outsourcing of software development has been both famous for the promises of great cost reductions, and infamous for the hidden costs associated with the challenges of organizing software work over distance. Experience sh...
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Offshore outsourcing of software development has been both famous for the promises of great cost reductions, and infamous for the hidden costs associated with the challenges of organizing software work over distance. Experience shows that many of these costs do not receive the deserved attention and are often excluded when making offshoring decisions. As a result, there is often a significant deviation between the expected and the realized costs of offshoring. In this paper, we investigate the awareness of the extra costs when making an offshoring decision, and the significance of the actual cost deviations. We conducted a single case study of a company that carried out an offshore outsourcing pilot project. We collected qualitative data from interviews, observations and a retrospective, and quantitative data on the costs and effort associated with the project. We conclude that the company was aware of the hidden cost factors, but largely underestimated their significance. The costs that surfaced in the studied project accounted for a total deviation of 181% and several individual cost categories with more than 400% overrun. The two main cost drivers in our study were the distance and poor process fit, which escalated the investments needed to make the collaboration work. Our results suggest that pilots are useful to understand the key problem areas in an offshoring collaboration, but too limited to shed light on all potential problems (e.g. turnover) due to the short timeframe. We also conclude that results of pilot projects shall not be the only data source when calculating the true costs of offshoring, since the start-up phase of an offshoring relationship carries large investments. Finally, we provide recommendations for companies in a similar situation on how to run and learn from offshore outsourcing pilot projects.
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摘要 :
Wireless sensor network (WSN) has attracted a lot of interest for its wide range of practical applications. The energy-resource limitation of WSN demands transmissions between sensor nodes to be high efficiency. Random linear netw...
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Wireless sensor network (WSN) has attracted a lot of interest for its wide range of practical applications. The energy-resource limitation of WSN demands transmissions between sensor nodes to be high efficiency. Random linear network coding (RLNC) exploits the broadcast and distributed nature of WSN to improve the throughput of network. The throughput gain brought by RLNC grows up as the generation size increased, while the decoding complexity has a cubic growth, being unacceptable for the energy-resource limited WSN. In this paper, we propose a segment linear network coding (SLNC) scheme which reduces the decoding complexity dramatically through adding constraints to the encoding coefficients and dividing a complex matrix inverse operation into several simple ones at receiver. Proved by theoretical analysis and simulation results, we show that SLNC achieves a fairly low decoding complexity with seldom increase on the overhead of network.
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摘要 :
Wireless sensor network (WSN) has attracted a lot of interest for its wide range of practical applications. The energy-resource limitation of WSN demands transmissions between sensor nodes to be high efficiency. Random linear netw...
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Wireless sensor network (WSN) has attracted a lot of interest for its wide range of practical applications. The energy-resource limitation of WSN demands transmissions between sensor nodes to be high efficiency. Random linear network coding (RLNC) exploits the broadcast and distributed nature of WSN to improve the throughput of network. The throughput gain brought by RLNC grows up as the generation size increased, while the decoding complexity has a cubic growth, being unacceptable for the energy-resource limited WSN. In this paper, we propose a segment linear network coding (SLNC) scheme which reduces the decoding complexity dramatically through adding constraints to the encoding coefficients and dividing a complex matrix inverse operation into several simple ones at receiver. Proved by theoretical analysis and simulation results, we show that SLNC achieves a fairly low decoding complexity with seldom increase on the overhead of network.
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