The reduction behaviors and characteristics of products of the Fe-Cr-O system (FeCr2O4 and Fe2O3+Cr2O3) and Fe-Cr-Ni-O system (Fe2O3+Cr2O3+NiO) under various conditions were studied. The results show that more ...The reduction behaviors and characteristics of products of the Fe-Cr-O system (FeCr2O4 and Fe2O3+Cr2O3) and Fe-Cr-Ni-O system (Fe2O3+Cr2O3+NiO) under various conditions were studied. The results show that more Fe-Cr or Fe-Cr-Ni solution and less residual carbon content were obtained at higher temperatures and lower initial molar ratio of C to O (nC:nO). The degree of reduction was highly dependent on both time and temperature, and the residual carbon content greatly increased with increasing nC:nO at each temperature. The products generated during the carbothermic reduction of the Fe-Cr-O system were examined using X-ray diffraction (XRD). A scanning electron microscope (SEM) coupled with energy dispersive spectrometer was used to observe the microstructure and the distribution of elements in the various phases of the final reduction products of the Fe-Cr-O and Fe-Cr-Ni-O.展开更多
Catch and effort data were analyzed to estimate the maximum sustainable yield (MSY) of King Soldier Bream, Argyrops spinifer (Forsskal, 1775, Family: Sparidae), and to evaluate the present status of the fish stoc...Catch and effort data were analyzed to estimate the maximum sustainable yield (MSY) of King Soldier Bream, Argyrops spinifer (Forsskal, 1775, Family: Sparidae), and to evaluate the present status of the fish stocks exploited in Pakistani waters. The catch and effort data for the 25-years period 1985-2009 were analyzed using two computer software packages, CEDA (catch and effort data analysis) and ASPIC (a surplus production model incorporating covariates). The maximum catch of 3 458 t was observed in 1988 and the minimum catch of 1 324 t in 2005, while the average annual catch ofA. spinifer over the 25 years was 2 500 t. The surplus production models of Fox, Schaefer, and Pella Tomlinson under three error assumptions of normal, log-normal and gamma are in the CEDA package and the two surplus models of Fox and logistic are in the ASPIC package. In CEDA, the MSY was estimated by applying the initial proportion (IP) of 0.8, because the starting catch was approximately 80% of the maximum catch. Except for gamma, because gamma showed maximization failures, the estimated results of MSY using CEDA with the Fox surplus production model and two error assumptions, were 1 692.08 t (R^2=0.572) and 1 694.09 t (R^2=0.606), respectively, and from the Schaefer and the Pella Tomlinson models with two error assumptions were 2 390.95 t (R^2=0.563), and 2 380.06 t (R^2=0.605), respectively. The MSY estimated by the Fox model was conservatively compared to the Schaefer and Pella Tomlinson models. The MSY values from Schaefer and Pella Tomlinson models were the same. The computed values of MSY using the ASPIC computer software program with the two surplus production models of Fox and logistic were 1 498 t (R^2=0.917), and 2 488 t (R^2=0.897) respectively. The estimated values of MSY using CEDA were about 1 700-2 400 t and the values from ASPIC were 1 500-2 500 t. The estimates output by the CEDA and the ASPIC packages indicate that the stock is overfished, and needs some effective management to reduce the fishing effort of the species in Pakistani waters.展开更多
Pakistani marine waters are under an open access regime. Due to poor management and policy implications, blind fishing is continued which may result in ecological as well as economic losses. Thus, it is of utmost impo...Pakistani marine waters are under an open access regime. Due to poor management and policy implications, blind fishing is continued which may result in ecological as well as economic losses. Thus, it is of utmost importance to estimate fishery resources before harvesting. In this study, catch and effort data, 1996-2009, of Kiddi shrimp Parapenaeopsis stylifera fishery from Pakistani marine waters was analyzed by using specialized fishery software in order to know fishery stock status of this commercially important shrimp. Maximum, minimum and average capture production ofP. stylifera was observed as 15 912 metric tons (mr) (1997), 9 438 mt (2009) and 11 667 mt/a. Two stock assessment tools viz. CEDA (catch and effort data analysis) and ASPIC (a stock production model incorporating covariates) were used to compute MSY (maximum sustainable yield) of this organism. In CEDA, three surplus production models, Fox, Schaefer and Pella-Tomlinson, along with three error assumptions, log, log normal and gamma, were used. For initial proportion (IP) 0.8, the Fox model computed MSY as 6 858 nat (CV=0.204, R^2=0.709) and 7 384 mt (CV=0.149, R^2=0.72) for log and log normal error assumption respectively. Here, gamma error produced minimization failure. Estimated MSY by using Schaefer and Pella-Tomlinson models remained the same for log, log normal and gamma error assumptions i.e. 7 083 mt, 8 209 mt and 7 242 mt correspondingly. The Schafer results showed highest goodness of fit R2 (0.712) values. ASPIC computed MSY, CV, R2, FMsv and BMsv parameters for the Fox model as 7 219 nat, 0.142, 0.872, 0.111 and 65 280, while for the Logistic model the computed values remained 7 720 mt, 0.148, 0.868, 0.107 and 72 110 correspondingly. Results obtained have shown that P. stylifera has been overexploited. Immediate steps are needed to conserve this fishery resource for the future and research on other species of commercial importance is urgently needed.展开更多
Rice fields provide food for over half of the world population but are also an important source of atmospheric CH(4). Using the climate-based GIS empirical model and the meteorological data collected from 600 meteorol...Rice fields provide food for over half of the world population but are also an important source of atmospheric CH(4). Using the climate-based GIS empirical model and the meteorological data collected from 600 meteorological stations in China, with county as the basic unit, the net primary productivity (NPP) of rice fields in China in 1990, 1995, 1998, and 2000 were estimated to be in the range from 202.19x10(12)g C in 1990 to 163.46x10(12)g C in 2000. From the measured data of the factors affecting CH(4) emission and NPP, the conversion ratio of the NPP into CH(4) emission for the rice fields of China was determined to be 1.8%. Using this ratio and estimated NPP, the CH(4) emissions from rice fields of China in 1990, 1995, 1998, and 2000 were estimated to be 7.24x10(12), 6.31x10(12), 6.77x10(12) and 5.85x10(12)g CH(4), respectively.展开更多
In order to investigate the influence factors of zero excess activated sludge (EAS) process by ozonation, a 100 L membrane bioreactor coupled with a sludge ozonation unit (MBR-SO) was performed for 80 d without EAS wa...In order to investigate the influence factors of zero excess activated sludge (EAS) process by ozonation, a 100 L membrane bioreactor coupled with a sludge ozonation unit (MBR-SO) was performed for 80 d without EAS wasting. Some mathematical models were developed to elucidate the relationship between process parameters and the operating effects. It is considered that the sludge lysing ratio (ξ), produced COD per unit mass lysed MLSS (η), observed sludge yield coefficient (Yobs) and intrinsic yield coefficient for COD produced by lysed sludge (Y2) significantly affect the flowrate to ozonation unit (q). When q is 0.0067 times of influent flowrate (Q) and ξ is about 0.72 for each batch ozonation, a relatively stable MLSS concentration of 8168 mg/L and zero Yobs are achieved in the MBR-SO system. The calculation of sludge disintegration number indicates that the high ξ can apparently decrease the sludge amount needed for ozonation. At the same ozone dose, the low input ozone concentration and high flowrate can enhance the sludge lysing effects and a low energy consumption of 0.041 Yuan/m3 wastewater is obtained.展开更多
Logging residue can be defined as any form of wood, which under the highest stage of technological development could be used in manufacturing but is left in the forest during logging. Lumber production from logging re...Logging residue can be defined as any form of wood, which under the highest stage of technological development could be used in manufacturing but is left in the forest during logging. Lumber production from logging residues of a previous logging activity by a timber firm was undertaken with the objective of determining the suitability of utilizing buttressed-stumps as raw material for the timber industry. A horizontal mobile bandsaw machine was used to process the buttressed-stumps into lumber. The machine was characterized by a thin-kerr sawing technology (kerf-width 1.6 mm) compared to the conventional bandsaw machines of kerr-widths ranging from 3.0-4.5 mm. Lumber value and volume yields, fuel consumption rate, frequency of tool replacement and lumber production rate were assessed. Results indicated that there is the potential to increase timber production from logging residues by utilizing buttressed-stumps. Lumber value and volume yields of eight timber species investigated in this study ranged from 5%-31% and 34%-54% respectively. Fuel consumption rate which increased with increasing wood density, ranged from 5-14.5 liters/m3 of lumber produced. Frequency of saw replacement increased with increasing wood density. The number of saws required to produce one cubic meter of lumber, ranged from 1 to 7. Lumber production rate ranged from 0.10-0.38 m3/hour, increasing with decreasing wood density.展开更多
Nine targets which stand both for the static characteristic of produced formations and the dynamic parameter of wells including the average permeability,variation coefficient of permeability,moving capability,remainin...Nine targets which stand both for the static characteristic of produced formations and the dynamic parameter of wells including the average permeability,variation coefficient of permeability,moving capability,remaining recoverable reserves,coefficient of flooding,daily oil production,increasing rate of water cut,cumulative liquid production per unit meter and efficiency index of oil production are selected as the evaluation indexes,a novel model to evaluate the porous formations in long-term waterflooding sand reservoir was established by using the support vector machine and clustering analysis. Data of 57 wells from Shentuo 21 block Shengli oilfield was analyzed by using the model. Four kinds of formation groups were gained. According to the analysis result,different adjustment solutions were put forward to develop the relevant formations. The Monthly oil production increased 7.6 % and the water cut decreased 8.9 % after the adjusted solutions. Good results indicate that the learning from this method gained will be valuable adding to other long-term waterflooding sand reservoirs in Shengli oilfield and other similar reservoirs worldwide.展开更多
Surface drilling was performed at the Luling Coal Mine,in Huaibei,to shorten the period required for gas draining.The experimental study was designed to reduce the cost of gas control by efficiently draining gas from ...Surface drilling was performed at the Luling Coal Mine,in Huaibei,to shorten the period required for gas draining.The experimental study was designed to reduce the cost of gas control by efficiently draining gas from the upper protected layer.The structural arraignment and technical principles of pressure relief via surface drilling are discussed.Results from the trial showed that gas drained from the surface system over a period of 10 months.The total amount of collected gas was 248.4 million m^3.The gas draining occurred in three stages:a growth period;a period of maximum gas production;and an attenuation period.The period of maximum gas production lasted for 4 months.During this time the methane concentration ranged from 60%to 90%and the average draining rate was 10.6 m^3/min.Combined with other methods of draining it was possible to drain 70.6%of the gas from middle coal seam groups.The amount of residual gas dropped to 5.2 m^3/ton,and the pressure of the residual gas fell to 0.53 MPa, thereby eliminating the outburst danger in the middle coal seam groups.The factors affecting pressure relief gas draining by surface drilling were analysed.展开更多
In this paper, by in-depth geological research of Kalamkas Oilfield in Central Asia, the geological body has been re-ascertained; combined with fine study of reservoir engineering, based on the understanding of the di...In this paper, by in-depth geological research of Kalamkas Oilfield in Central Asia, the geological body has been re-ascertained; combined with fine study of reservoir engineering, based on the understanding of the distribution of remaining oil horizontal wells have been given full play to stabilizing oil production and controlling water cut, reducing the producing pressure drop, improving well productivity and other advantages, and the development and deployment has been optimized; horizontal wells have been applied to solve problems such as old well casing damages, shutting down wells, low-productivity and low- efficiency wells, and high water cut wells to improve the utilization rate of old wells; through separate layer system improved injection production pattern, adjustment wells have been optimized and deployed, and part measures wells have been preferably selected to tap the residual oil improve the degree of reserves control realize the stabilization of oil production and control of water cut in an old oilfield, and further improve the development effects.展开更多
Earning management is a pioneering research subject and a world problem rising in international economics and accounting field since 1980s. It is also common in listed companies of our country and has a degree of adve...Earning management is a pioneering research subject and a world problem rising in international economics and accounting field since 1980s. It is also common in listed companies of our country and has a degree of adverse effect on sound operation of market economy. The exploration on earning management firstly is based on knowing the related research achievements at home and abroad to compare the environment and background of different theories generating. Then the paper starts from the definition to analyze the effect of concrete accounting standards on earning management complemented with the proof of cases. Lastly, the paper analyzes the data of some listed companies from 2008 to 2011 with empirical method, and verifies the effect of implementing asset impairment criteria on earning management of listed companies from the view of industry. Focusing on the comparative study of industries, the paper draws valuableconclusion which is consistent with the real situation, and the paper refines the research of domestic earning management.展开更多
This paper work aims to response the request for immediate intervention of cultural heritage preservation in Kosovo, with the aim of protection against the harmful consequences of insufficient knowledge leading to a m...This paper work aims to response the request for immediate intervention of cultural heritage preservation in Kosovo, with the aim of protection against the harmful consequences of insufficient knowledge leading to a misuse of technology and to ill-considered approaches. The DGT (dwelling-garret type) is an important vernacular study case. The DGT is a historic building of 18th century, located in the core of Lebusha Village, Municipality of Peja, an architectural construction characterized by two concentric volumes at rectangular layout, very dynamic at horizontal composition, obtained by the movement of two differently constructional materials volumes, stone masonry and timber assembly, and covered with roof clay tiles. In view of its esthetic and artistic values, its important role at developing chain of Kosovo's rural dwellings typology, and its method of construction, the building should be listed as a monument under state protection. Hence, immediate protection interventions, such as conservation of wooden and stone envelope, improvement of walls and finish works, and drainage infrastructure, are considered as the minimum requirement.展开更多
At present, the focus is on distributed energy generation with low or negative carbon emissions as well as high conversion yields. In Romania, the renewable energy resource that can be used and produced when and where...At present, the focus is on distributed energy generation with low or negative carbon emissions as well as high conversion yields. In Romania, the renewable energy resource that can be used and produced when and wherever necessary is residual agricultural biomass with a potential of 31 million tons, which can produce over 40% of the national energy demand. Residual agricultural biomass is produced with an average energy efficiency of 6 kWh·bm/kWh input. The CHAB (combined heat and biochar production) concept produces high yield thermal energy as well as BC (biochar) with an average carbon footprint of 140 kg/ton biomass. If the energy produced is used to produce agricultural output, the negative carbon footprint increases by reducing the consumption of fossil fuels. It increases energy independence, the safety of agricultural production, the number of jobs, and regional economic development.展开更多
For some time, two major kinds of Total Factor Productivity (TFP) have existed independently of each other: the Solow residual and the Malmquist Productivity Index (MPI). The Solow residual was introduced in macr...For some time, two major kinds of Total Factor Productivity (TFP) have existed independently of each other: the Solow residual and the Malmquist Productivity Index (MPI). The Solow residual was introduced in macro economic growth models, and the MPI has been used in micro economics and management studies. As both indices were developed independently, few studies utilize both together and compare the results. This paper uses the same data to compare the two productivity indices by setting to determine the economic implications of combining the two indices. We discovered that we could decompose TFP with each aspect of the Soiow residual and MPI. We could then interpret their relationship in the business cycle. Our results indicated that the frontier shift in MPI of Japanese firms often occurred when the Solow residual increased, meaning that improving oroductivitv with the Solow residual could be generated by a firm that could shift new production frontiers.展开更多
This paper discusses the behavior of the thermal properties of polymer composites made of a natural polyurethane matrix and loads of different waste of HDPE (High density polyethylene) industry. This polymer is part...This paper discusses the behavior of the thermal properties of polymer composites made of a natural polyurethane matrix and loads of different waste of HDPE (High density polyethylene) industry. This polymer is partially crystalline, having amorphous phases and crystalline phases, HDPE type is harder and tougher than other polyethylenes, having a wide range of applications that depend almost exclusively on the processes for obtaining final products. After the process, waste from the manufacture of these products are discarded daily as they are not found effective ways to use this material. In this study we seek to use this "factory floor" to act as filler in a polyurethane matrix derived from the castor oil, which is a natural biodegradable. The residue loads were separated according to the process that originated in this way have been the A residue from the process of cork and the B residue derived from the extrusion process. Specimens in mass proportions of 10%, 20% and 30% polyethylene both loads were prepared and their thermal properties were mediated, these being the thermal conductivity (k), specific heat (c) and thermal diffusivity (~). By adding such fillers to castor polyurethane matrix, different behaviors were observed, because of the residue contributed to a reduction in conductivity and specific heat of the composite material. Since the residue B on average 47% higher than residue, caused an increase in these same properties as before the spaces filled with air only into the polyurethane are now filled with polyethylene grains. We can see then that the particle size of the HDPE waste has a direct influence on the improvement of the thermal properties of the analyzed composite material.展开更多
基金Project (51074025) supported by the National Natural Science Foundation of ChinaProject (FRF-SD-12-009A) supported by the Fundamental Research Funds for the Central Universities,China
文摘The reduction behaviors and characteristics of products of the Fe-Cr-O system (FeCr2O4 and Fe2O3+Cr2O3) and Fe-Cr-Ni-O system (Fe2O3+Cr2O3+NiO) under various conditions were studied. The results show that more Fe-Cr or Fe-Cr-Ni solution and less residual carbon content were obtained at higher temperatures and lower initial molar ratio of C to O (nC:nO). The degree of reduction was highly dependent on both time and temperature, and the residual carbon content greatly increased with increasing nC:nO at each temperature. The products generated during the carbothermic reduction of the Fe-Cr-O system were examined using X-ray diffraction (XRD). A scanning electron microscope (SEM) coupled with energy dispersive spectrometer was used to observe the microstructure and the distribution of elements in the various phases of the final reduction products of the Fe-Cr-O and Fe-Cr-Ni-O.
基金Supported by the Special Research Fund of Ocean University of China(No.201022001)
文摘Catch and effort data were analyzed to estimate the maximum sustainable yield (MSY) of King Soldier Bream, Argyrops spinifer (Forsskal, 1775, Family: Sparidae), and to evaluate the present status of the fish stocks exploited in Pakistani waters. The catch and effort data for the 25-years period 1985-2009 were analyzed using two computer software packages, CEDA (catch and effort data analysis) and ASPIC (a surplus production model incorporating covariates). The maximum catch of 3 458 t was observed in 1988 and the minimum catch of 1 324 t in 2005, while the average annual catch ofA. spinifer over the 25 years was 2 500 t. The surplus production models of Fox, Schaefer, and Pella Tomlinson under three error assumptions of normal, log-normal and gamma are in the CEDA package and the two surplus models of Fox and logistic are in the ASPIC package. In CEDA, the MSY was estimated by applying the initial proportion (IP) of 0.8, because the starting catch was approximately 80% of the maximum catch. Except for gamma, because gamma showed maximization failures, the estimated results of MSY using CEDA with the Fox surplus production model and two error assumptions, were 1 692.08 t (R^2=0.572) and 1 694.09 t (R^2=0.606), respectively, and from the Schaefer and the Pella Tomlinson models with two error assumptions were 2 390.95 t (R^2=0.563), and 2 380.06 t (R^2=0.605), respectively. The MSY estimated by the Fox model was conservatively compared to the Schaefer and Pella Tomlinson models. The MSY values from Schaefer and Pella Tomlinson models were the same. The computed values of MSY using the ASPIC computer software program with the two surplus production models of Fox and logistic were 1 498 t (R^2=0.917), and 2 488 t (R^2=0.897) respectively. The estimated values of MSY using CEDA were about 1 700-2 400 t and the values from ASPIC were 1 500-2 500 t. The estimates output by the CEDA and the ASPIC packages indicate that the stock is overfished, and needs some effective management to reduce the fishing effort of the species in Pakistani waters.
基金Supported by the Earmarked Fund for Modern Agro-Industry Technology Research System of Chinathe Special Research Fund of Ocean University of China(No.201022001)
文摘Pakistani marine waters are under an open access regime. Due to poor management and policy implications, blind fishing is continued which may result in ecological as well as economic losses. Thus, it is of utmost importance to estimate fishery resources before harvesting. In this study, catch and effort data, 1996-2009, of Kiddi shrimp Parapenaeopsis stylifera fishery from Pakistani marine waters was analyzed by using specialized fishery software in order to know fishery stock status of this commercially important shrimp. Maximum, minimum and average capture production ofP. stylifera was observed as 15 912 metric tons (mr) (1997), 9 438 mt (2009) and 11 667 mt/a. Two stock assessment tools viz. CEDA (catch and effort data analysis) and ASPIC (a stock production model incorporating covariates) were used to compute MSY (maximum sustainable yield) of this organism. In CEDA, three surplus production models, Fox, Schaefer and Pella-Tomlinson, along with three error assumptions, log, log normal and gamma, were used. For initial proportion (IP) 0.8, the Fox model computed MSY as 6 858 nat (CV=0.204, R^2=0.709) and 7 384 mt (CV=0.149, R^2=0.72) for log and log normal error assumption respectively. Here, gamma error produced minimization failure. Estimated MSY by using Schaefer and Pella-Tomlinson models remained the same for log, log normal and gamma error assumptions i.e. 7 083 mt, 8 209 mt and 7 242 mt correspondingly. The Schafer results showed highest goodness of fit R2 (0.712) values. ASPIC computed MSY, CV, R2, FMsv and BMsv parameters for the Fox model as 7 219 nat, 0.142, 0.872, 0.111 and 65 280, while for the Logistic model the computed values remained 7 720 mt, 0.148, 0.868, 0.107 and 72 110 correspondingly. Results obtained have shown that P. stylifera has been overexploited. Immediate steps are needed to conserve this fishery resource for the future and research on other species of commercial importance is urgently needed.
文摘Rice fields provide food for over half of the world population but are also an important source of atmospheric CH(4). Using the climate-based GIS empirical model and the meteorological data collected from 600 meteorological stations in China, with county as the basic unit, the net primary productivity (NPP) of rice fields in China in 1990, 1995, 1998, and 2000 were estimated to be in the range from 202.19x10(12)g C in 1990 to 163.46x10(12)g C in 2000. From the measured data of the factors affecting CH(4) emission and NPP, the conversion ratio of the NPP into CH(4) emission for the rice fields of China was determined to be 1.8%. Using this ratio and estimated NPP, the CH(4) emissions from rice fields of China in 1990, 1995, 1998, and 2000 were estimated to be 7.24x10(12), 6.31x10(12), 6.77x10(12) and 5.85x10(12)g CH(4), respectively.
文摘In order to investigate the influence factors of zero excess activated sludge (EAS) process by ozonation, a 100 L membrane bioreactor coupled with a sludge ozonation unit (MBR-SO) was performed for 80 d without EAS wasting. Some mathematical models were developed to elucidate the relationship between process parameters and the operating effects. It is considered that the sludge lysing ratio (ξ), produced COD per unit mass lysed MLSS (η), observed sludge yield coefficient (Yobs) and intrinsic yield coefficient for COD produced by lysed sludge (Y2) significantly affect the flowrate to ozonation unit (q). When q is 0.0067 times of influent flowrate (Q) and ξ is about 0.72 for each batch ozonation, a relatively stable MLSS concentration of 8168 mg/L and zero Yobs are achieved in the MBR-SO system. The calculation of sludge disintegration number indicates that the high ξ can apparently decrease the sludge amount needed for ozonation. At the same ozone dose, the low input ozone concentration and high flowrate can enhance the sludge lysing effects and a low energy consumption of 0.041 Yuan/m3 wastewater is obtained.
文摘Logging residue can be defined as any form of wood, which under the highest stage of technological development could be used in manufacturing but is left in the forest during logging. Lumber production from logging residues of a previous logging activity by a timber firm was undertaken with the objective of determining the suitability of utilizing buttressed-stumps as raw material for the timber industry. A horizontal mobile bandsaw machine was used to process the buttressed-stumps into lumber. The machine was characterized by a thin-kerr sawing technology (kerf-width 1.6 mm) compared to the conventional bandsaw machines of kerr-widths ranging from 3.0-4.5 mm. Lumber value and volume yields, fuel consumption rate, frequency of tool replacement and lumber production rate were assessed. Results indicated that there is the potential to increase timber production from logging residues by utilizing buttressed-stumps. Lumber value and volume yields of eight timber species investigated in this study ranged from 5%-31% and 34%-54% respectively. Fuel consumption rate which increased with increasing wood density, ranged from 5-14.5 liters/m3 of lumber produced. Frequency of saw replacement increased with increasing wood density. The number of saws required to produce one cubic meter of lumber, ranged from 1 to 7. Lumber production rate ranged from 0.10-0.38 m3/hour, increasing with decreasing wood density.
基金supported by funds from the Key Pro-ject of Chinese National Programs for Fundamental Research and Development (863 Program) under thenumber 2007AA090701the Young and Mid-dle-aged Researchers Innovation and Technology Foun-dation of CNPC under the number 04E7029
文摘Nine targets which stand both for the static characteristic of produced formations and the dynamic parameter of wells including the average permeability,variation coefficient of permeability,moving capability,remaining recoverable reserves,coefficient of flooding,daily oil production,increasing rate of water cut,cumulative liquid production per unit meter and efficiency index of oil production are selected as the evaluation indexes,a novel model to evaluate the porous formations in long-term waterflooding sand reservoir was established by using the support vector machine and clustering analysis. Data of 57 wells from Shentuo 21 block Shengli oilfield was analyzed by using the model. Four kinds of formation groups were gained. According to the analysis result,different adjustment solutions were put forward to develop the relevant formations. The Monthly oil production increased 7.6 % and the water cut decreased 8.9 % after the adjusted solutions. Good results indicate that the learning from this method gained will be valuable adding to other long-term waterflooding sand reservoirs in Shengli oilfield and other similar reservoirs worldwide.
基金supported by the Key Project of the Natural Science Foundation of China(No.70533050 and 51004106)the Fundamental Research Funds for the Central Universities (No.2010QNB02)
文摘Surface drilling was performed at the Luling Coal Mine,in Huaibei,to shorten the period required for gas draining.The experimental study was designed to reduce the cost of gas control by efficiently draining gas from the upper protected layer.The structural arraignment and technical principles of pressure relief via surface drilling are discussed.Results from the trial showed that gas drained from the surface system over a period of 10 months.The total amount of collected gas was 248.4 million m^3.The gas draining occurred in three stages:a growth period;a period of maximum gas production;and an attenuation period.The period of maximum gas production lasted for 4 months.During this time the methane concentration ranged from 60%to 90%and the average draining rate was 10.6 m^3/min.Combined with other methods of draining it was possible to drain 70.6%of the gas from middle coal seam groups.The amount of residual gas dropped to 5.2 m^3/ton,and the pressure of the residual gas fell to 0.53 MPa, thereby eliminating the outburst danger in the middle coal seam groups.The factors affecting pressure relief gas draining by surface drilling were analysed.
文摘In this paper, by in-depth geological research of Kalamkas Oilfield in Central Asia, the geological body has been re-ascertained; combined with fine study of reservoir engineering, based on the understanding of the distribution of remaining oil horizontal wells have been given full play to stabilizing oil production and controlling water cut, reducing the producing pressure drop, improving well productivity and other advantages, and the development and deployment has been optimized; horizontal wells have been applied to solve problems such as old well casing damages, shutting down wells, low-productivity and low- efficiency wells, and high water cut wells to improve the utilization rate of old wells; through separate layer system improved injection production pattern, adjustment wells have been optimized and deployed, and part measures wells have been preferably selected to tap the residual oil improve the degree of reserves control realize the stabilization of oil production and control of water cut in an old oilfield, and further improve the development effects.
文摘Earning management is a pioneering research subject and a world problem rising in international economics and accounting field since 1980s. It is also common in listed companies of our country and has a degree of adverse effect on sound operation of market economy. The exploration on earning management firstly is based on knowing the related research achievements at home and abroad to compare the environment and background of different theories generating. Then the paper starts from the definition to analyze the effect of concrete accounting standards on earning management complemented with the proof of cases. Lastly, the paper analyzes the data of some listed companies from 2008 to 2011 with empirical method, and verifies the effect of implementing asset impairment criteria on earning management of listed companies from the view of industry. Focusing on the comparative study of industries, the paper draws valuableconclusion which is consistent with the real situation, and the paper refines the research of domestic earning management.
文摘This paper work aims to response the request for immediate intervention of cultural heritage preservation in Kosovo, with the aim of protection against the harmful consequences of insufficient knowledge leading to a misuse of technology and to ill-considered approaches. The DGT (dwelling-garret type) is an important vernacular study case. The DGT is a historic building of 18th century, located in the core of Lebusha Village, Municipality of Peja, an architectural construction characterized by two concentric volumes at rectangular layout, very dynamic at horizontal composition, obtained by the movement of two differently constructional materials volumes, stone masonry and timber assembly, and covered with roof clay tiles. In view of its esthetic and artistic values, its important role at developing chain of Kosovo's rural dwellings typology, and its method of construction, the building should be listed as a monument under state protection. Hence, immediate protection interventions, such as conservation of wooden and stone envelope, improvement of walls and finish works, and drainage infrastructure, are considered as the minimum requirement.
文摘At present, the focus is on distributed energy generation with low or negative carbon emissions as well as high conversion yields. In Romania, the renewable energy resource that can be used and produced when and wherever necessary is residual agricultural biomass with a potential of 31 million tons, which can produce over 40% of the national energy demand. Residual agricultural biomass is produced with an average energy efficiency of 6 kWh·bm/kWh input. The CHAB (combined heat and biochar production) concept produces high yield thermal energy as well as BC (biochar) with an average carbon footprint of 140 kg/ton biomass. If the energy produced is used to produce agricultural output, the negative carbon footprint increases by reducing the consumption of fossil fuels. It increases energy independence, the safety of agricultural production, the number of jobs, and regional economic development.
文摘For some time, two major kinds of Total Factor Productivity (TFP) have existed independently of each other: the Solow residual and the Malmquist Productivity Index (MPI). The Solow residual was introduced in macro economic growth models, and the MPI has been used in micro economics and management studies. As both indices were developed independently, few studies utilize both together and compare the results. This paper uses the same data to compare the two productivity indices by setting to determine the economic implications of combining the two indices. We discovered that we could decompose TFP with each aspect of the Soiow residual and MPI. We could then interpret their relationship in the business cycle. Our results indicated that the frontier shift in MPI of Japanese firms often occurred when the Solow residual increased, meaning that improving oroductivitv with the Solow residual could be generated by a firm that could shift new production frontiers.
文摘This paper discusses the behavior of the thermal properties of polymer composites made of a natural polyurethane matrix and loads of different waste of HDPE (High density polyethylene) industry. This polymer is partially crystalline, having amorphous phases and crystalline phases, HDPE type is harder and tougher than other polyethylenes, having a wide range of applications that depend almost exclusively on the processes for obtaining final products. After the process, waste from the manufacture of these products are discarded daily as they are not found effective ways to use this material. In this study we seek to use this "factory floor" to act as filler in a polyurethane matrix derived from the castor oil, which is a natural biodegradable. The residue loads were separated according to the process that originated in this way have been the A residue from the process of cork and the B residue derived from the extrusion process. Specimens in mass proportions of 10%, 20% and 30% polyethylene both loads were prepared and their thermal properties were mediated, these being the thermal conductivity (k), specific heat (c) and thermal diffusivity (~). By adding such fillers to castor polyurethane matrix, different behaviors were observed, because of the residue contributed to a reduction in conductivity and specific heat of the composite material. Since the residue B on average 47% higher than residue, caused an increase in these same properties as before the spaces filled with air only into the polyurethane are now filled with polyethylene grains. We can see then that the particle size of the HDPE waste has a direct influence on the improvement of the thermal properties of the analyzed composite material.