In order to evaluate the efficiency of the automated storage/retrieval system(AS/RS)accurately,and compare different layouts of the AS/RS using mean travel time,under randomized storage conditions,an exact,geometry-ba...In order to evaluate the efficiency of the automated storage/retrieval system(AS/RS)accurately,and compare different layouts of the AS/RS using mean travel time,under randomized storage conditions,an exact,geometry-based analytical model is presented.The model can be used to compute the expected single-command and dual-command travel time for a storage/retrieval(S/R)machine which can travel simultaneously horizontally and vertically as it moves along a storage aisle.The rack may be either square in time or non square in time.Additionally,the alternative layouts of the AS/RS and travel-time models are examined.Comparing with setting the I/O point at the left-lower corner of the rack,setting the I/O point at any point at the vertical edge can help enhance the efficiency of the AS/RS.展开更多
For electronic piezo gauge used for testing gun chamber pressure, its internal miniature pulse-powered photoelectric invert switch cannot often be powered up normally. To solve this problem, a test system for invert s...For electronic piezo gauge used for testing gun chamber pressure, its internal miniature pulse-powered photoelectric invert switch cannot often be powered up normally. To solve this problem, a test system for invert switch is presented to verify the reliability of the invert switch. The test system uses complex programmable logic device (CPLD) to control data acquisition of A/D converter and data storage of external flash memory, and then transmits the acquired data to a computer for data analysis and processing. The test system can provide the required sampling frequency of the signal in high temperature, normal temperature and low temperature environments, and the reliability of the invert switch can be verified according to the signal parameters. The results show that the test system has high precision and the tested invert switch has low power consumption and high reliability.展开更多
This paper describes the architecture of global distributed storage system for data grid. It focue on the management and the capability for the maximum users and maximum resources on the Internet, as well as performan...This paper describes the architecture of global distributed storage system for data grid. It focue on the management and the capability for the maximum users and maximum resources on the Internet, as well as performance and other issues.展开更多
To reduce the time required to complete the regeneration process of erasure codes, we propose a Tree-structured Parallel Regeneration (TPR) scheme for multiple data losses in distributed storage systems. Under the sch...To reduce the time required to complete the regeneration process of erasure codes, we propose a Tree-structured Parallel Regeneration (TPR) scheme for multiple data losses in distributed storage systems. Under the scheme, two algorithms are proposed for the construction of multiple regeneration trees, namely the edge-disjoint algorithm and edge-sharing algorithm. The edge-disjoint algorithm constructs multiple independent trees, and is simple and appropriate for environments where newcomers and their providers are distributed over a large area and have few intersections. The edge-sharing algorithm constructs multiple trees that compete to utilize the bandwidth, and make a better utilization of the bandwidth, although it needs to measure the available band-width and deal with the bandwidth changes; it is therefore difficult to implement in practical systems. The parallel regeneration for multiple data losses of TPR primarily includes two optimizations: firstly, transferring the data through the bandwidth optimized-paths in a pipe-line manner; secondly, executing data regeneration over multiple trees in parallel. To evaluate the proposal, we implement an event-based simulator and make a detailed comparison with some popular regeneration methods. The quantitative comparison results show that the use of TPR employing either the edge-disjoint algorithm or edge-sharing algorithm reduces the regeneration time significantly.展开更多
First and Second Law analyses were conducted to evaluate the performance of a closed latent heat thermal energy storage (LHTES) system employing calcium chloride hexahydrate (CaCl2·6H2O). The First and the Second...First and Second Law analyses were conducted to evaluate the performance of a closed latent heat thermal energy storage (LHTES) system employing calcium chloride hexahydrate (CaCl2·6H2O). The First and the Second Laws of thermodynamics were applied to the system from viewpoint of energy and exergy analyses, respectively. The energy storage tank in the system is neither fully mixed nor fully stratified. It may be considered as semithermal stratified. Experimente that include both charging and discharging periods were performed on sunny winter days in 1996. The energy and exergy variations and the overall energy and exergy efficiencies of the closed LHTES system were calculated for the complete charging and discharging cycle of the selected fifteen clear-sky winter days. Mean energy and exergy efficiencies were found to be 55.20% and 34.83%, respectively.展开更多
To cope with the impact of big data,it is proposed to integrate the traditionally individual computing,communications and storage systems,which are getting inevitably converged.An effective information system capacity...To cope with the impact of big data,it is proposed to integrate the traditionally individual computing,communications and storage systems,which are getting inevitably converged.An effective information system capacity is introduced and discussed,aimed at excavating potentials of information system under a new paradigm with more degrees of freedom.展开更多
This paper proposes a content addres sable storage optimization method, VDeskCAS, for desktop virtualization storage based disaster backup storage system. The method implements a blocklevel storage optimization, by em...This paper proposes a content addres sable storage optimization method, VDeskCAS, for desktop virtualization storage based disaster backup storage system. The method implements a blocklevel storage optimization, by employing the algorithms of chunking image file into blocks, the blockffmger calculation and the block dedup li cation. A File system in Use Space (FUSE) based storage process for VDeskCAS is also introduced which optimizes current direct storage to suit our content addressable storage. An interface level modification makes our system easy to extend. Experiments on virtual desktop image files and normal files verify the effectiveness of our method and above 60% storage volume decrease is a chieved for Red Hat Enterprise Linux image files. Key words: disaster backup; desktop virtualization; storage optimization; content addressable storage展开更多
Night sky cooling is explored as an alternative to the conventional cooling technologies using fossil fuels. The night sky cooling method is based on the long wave radiation of unglazed collectors to the sky at night....Night sky cooling is explored as an alternative to the conventional cooling technologies using fossil fuels. The night sky cooling method is based on the long wave radiation of unglazed collectors to the sky at night. An evaluation of the night sky cooling system is present for a residential building in three cities of Australia, namely Alice Springs, Darwin and Melbourne. The system comprises an unglazed flat plate solar collector integrated with borehole storage. It uses night sky radiation to reduce the temperature of the ground near to the boreholes. The system was simulated with TRNSYS, a transient simulation program. The simulation results for adequately sized systems show that night sky radiation is able to reduce the coolth storage borehole temperature and the proposed system is able to meet the cooling load of the residential building simulated in three locations. Borchole lengths of 270, 318 and 106 m are required for coolth storage with 90, 260 and 14 m2 collector area for heat rejection in Alice Springs, Darwin and Melbourne, respectively. At the 20th simulation year, the proposed system is able to achieve a system cooling coefficient of performance of 2.2 in Alice Springs, and 2.8 in Darwin and Melbourne.展开更多
More and more embedded devices, such as mobile phones, tablet PCs and laptops, are used in every field, so huge files need to be stored or backed up into cloud storage. Optimizing the performance of cloud storage is v...More and more embedded devices, such as mobile phones, tablet PCs and laptops, are used in every field, so huge files need to be stored or backed up into cloud storage. Optimizing the performance of cloud storage is very important for Internet development. This paper presents the performance evaluation of the open source distributed storage system, a highly available, distributed, eventually consistent object/blob store from Open Stack cloud computing components. This paper mainly focuses on the mechanism of cloud storage as well as the optimization methods to process different sized files. This work provides two major contributions through comprehensive performance evaluations. First, it provides different configurations for Open Stack Swift system and an analysis of how every component affects the performance. Second, it presents the detailed optimization methods to improve the performance in processing different sized files. The experimental results show that our method improves the performance and the structure. We give the methods to optimize the object-based cloud storage system to deploy the readily available storage system.展开更多
The desire to speed up secondary storage systems has lead to the development of redundant arrays of independent disks (RAID) which incorporate redundancy utilizing erasure codes. A 'cluttered ordering' is utilized...The desire to speed up secondary storage systems has lead to the development of redundant arrays of independent disks (RAID) which incorporate redundancy utilizing erasure codes. A 'cluttered ordering' is utilized for designing an effective writing order to a RAID system. Cohen, Colboum and Froncek (2001) gave a cyclic construction of cluttered orderings for the complete graph by utilizing the notion of a 'wrapped p-labelling'. Since wrapped p-labellings as cluttered orderings for the complete graph look such as ladders, they are also called as ladder orderings. Cohen and Colboum (2004) gave a characteristic of ladder orderings. In this paper, we give an algorithm in order to generate ladder orderings.展开更多
An ADS (automated dispensing system) was implemented in our hospital pharmacy in 2008 to optimize and secure the medication process. The main objective of this study was to compare the projected and the real ROI (r...An ADS (automated dispensing system) was implemented in our hospital pharmacy in 2008 to optimize and secure the medication process. The main objective of this study was to compare the projected and the real ROI (return on investment), after seven years of use. ROI was calculated annually (from 2008 to 2015), by deducting the cost of investment (ADS buying and implementation, maintenance, repairs and ADS upgrade) from the cost saving (drugs stock reduction and decrease of pharmacy staff dedicated to global dispensing). In 2015, total costs saving (+$1,141,987) were divided between decreasing drug stock value and reduction of pharmacy staff. Total costs of investment (-$978,656) were acquisition, maintenance, repairs and an unplanned upgrade costs. Finally, the real ROI was +$163,331 after seven years of use. In 2008, projected ROI was +$410,786. The real payback period has been increased by approximately two years (six years of use, instead of four years as expected). Despite their cost, ADSs are a worthwhile investment, leading to a ROI within a few years. These economic considerations should be put into perspective with optimization of drugs stock management, greater efficiency of the global dispensing process, securitization of medication process and redeployment of pharmacy staff.展开更多
Due to the growing concern about the agricultural phosphorus (P) losses pollution, an in-depth understanding of P in paddy soils of China would be helpful in providing a national perspective of the environmental impac...Due to the growing concern about the agricultural phosphorus (P) losses pollution, an in-depth understanding of P in paddy soils of China would be helpful in providing a national perspective of the environmental impact of P cycling and fertility on China's farms. In this study, we evaluated the P storage and the P density of paddy soils in China, characterized the spatial variations of P among the subgroups of paddy soils and soil regions in China, and evaluated the P data using GIS-based analysis, which included a newly compiled 1:1 000 000 digital soil map of China, and using 1 490 soil profiles. The available and total P densities of paddy soils were 6.7 and 698.5 g m -3 , respectively. Overall in China, the total P storage within 1 m of paddy soils was estimated to be 330.2 Tg. The P density of paddy soils varied substantially with subgroups due to the different soil water regimes such as groundwater table and soil drainage. The P availability in paddy soils, especially in surface layer, was higher in high temperature and precipitation areas. Further research is needed to examine more anthropogenic impact factors, such as increasing use of chemical fertilizer.展开更多
Mountains and plateaus in Southwest China contain many subalpine and alpine wetlands, with signifieant hydroecological functions. But ungauged or poorly gauged eonditions limit the study and understanding of hydrologi...Mountains and plateaus in Southwest China contain many subalpine and alpine wetlands, with signifieant hydroecological functions. But ungauged or poorly gauged eonditions limit the study and understanding of hydrological regimes of these wetland types. This study selects an ungauged subalpine wetland - Napahai in Northwest Yunnan, China - as a case for developing a practical approach to revealing its storage-area relationship of open water. A Trimble R8 GNSS (Global Navigation Satellites Systems) RTK (Real-time Kinematic system) and sonar fathometer were used to survey fine- resolution elevation data and generate a digital elevation model of the Napahai Wetland. Forty-four Landsat images from 1987 to 2Oll were collected, and the Normalized Difference Water Index was used to classify open water features in the area. The area of open water in Napahai was ealculated for each phase. With these data and a developed conceptual model, the storage of open water for each phase was estimated using ArcGIS tools. Both storage and area of open water showed significant intra-annual and inter-annual variations. In the rainy season, the monthly change of average storage of open water in Napahai showed about 1-2 months lag behind mean monthly rainfall. The storage-area relationship of open water was well fit by a power function equation (R2=0.91, n=44). This study indicates that if detailedelevations are available for similarly ungauged subalpine wetlands in Southwest China, researchers can use this practical approach to estimate multi- temporal areas and storages and reveal the storage- area relationship of open water in the wetlands. The study provided valuable information of this ease wetland for optimizing its hydro-ecological managements and a new method to wetland researchers and managers for the hydrological study of similarly ungauged wetland complex.展开更多
A hydrogen production and conversion plant from wind power was installed in the Sotavento wind farm by Gas Natural and the Galician Government. This facility is the highest electrolysis power installed at the European...A hydrogen production and conversion plant from wind power was installed in the Sotavento wind farm by Gas Natural and the Galician Government. This facility is the highest electrolysis power installed at the European level. It consists of an electrolyser of 300 kW, a piston compressor, a 1,725 Nm3 H2 storage system and an engine of 55 kW. This pilot plant is being operated by Natural Gas in order to extrapolate its behavior to that of an industrial facility capable of managing all the production of Sotavento wind farm following different strategies: balancing, peak-shaving and repowering. In this paper, preliminary results at the facility are presented. The aim of these first tests has been to describe the operation of equipment under operating conditions required in the management of wind power production, in order to understand the behavior of the different equipment and try to make them suitable for this type of applications. This paper shows the difficulty of operating these systems under the wind power requirements.展开更多
The present experimental investigation covers the construction of a LHTES (latent heat thermal energy storage system), which uses NaNO_3 (sodium nitrate) as PCM (phase change material). The storage unit is fille...The present experimental investigation covers the construction of a LHTES (latent heat thermal energy storage system), which uses NaNO_3 (sodium nitrate) as PCM (phase change material). The storage unit is filled with 300 kg of the PCM. For the heat transfer, a vertically arranged bimetallic mono tube with longitudinal fins is used. The fins increase the heat flux into/from the PCM. Thermal oil is used as a heat transfer medium, as it allows working temperature up to 400 ℃. This thermal energy storage is able to store 60 kWh of thermal energy and can be loaded with a power up to 200 kW. One part of the investigation results presented in this paper was the determination of the storable energy and the comparison with data from literature and calculations. Additionally, the melting behavior of the PCM was measured with temperature sensors located at different positions over the height of the storage unit. Finally, the entrance of the heat transfer medium was changed from the top to the bottom of the thermal energy storage unit and a different melting behavior could be detected.展开更多
Global Memory Net (GMNet) is intended to be an effective gateway to the world cultural, historical, and heritage image collections from selected academic educational and research partners in the world. Much of these u...Global Memory Net (GMNet) is intended to be an effective gateway to the world cultural, historical, and heritage image collections from selected academic educational and research partners in the world. Much of these unique collections of great value to education and research are not currently accessible due to distance, form, and technical barriers. This project is to find new ways to enable users to access and exploit these significant research collections via global network. As GMNet is ending its first 5-year phase in October 2005, it has contributed substantially to the community building in digital library development by ac- commodating numerous collaborators and technical staff from various parts of the world to spend 3 to 5 months as a full-member of the GMNet team in Boston. They have come from different parts of China—such as Sichuan, Hainan, Shanghai and Xi’an; Croatia; and Hanoi, Vietnam. In addition to contribute to the overall system development and enhancement of system function- alities, they have brought valuable sample image collections of their own institutions/countries, and actually developed prototype collections as a part of GMNet. This paper describes the exciting and productive experience of the first of this visiting research group in developing the GMNet’s Version 2.0 PHP-based system under Prof. Chen’s overall supervision. It also describes both the system’s technical level structure—user/Web-based application/data, and complex functionalities with multi-collection, multi-lingual, multi-modal searching capabilities; system management capabilities; as well as provisions for user uploads and retrieval for our own projects. This Version 2.0 system is built on the Linux/Apache/PHP/MySQL platform. What is described in this paper is an actual case which has formed a base for further new development by others in the research group. It demonstrates fully the value of the synergistic collaboration among global partners for universal digital library development. More information can be found in http://www.memorynet.org/.展开更多
基金The National Key Technology R&D Program of China during the 11th Five-Year Plan Period(No.2006BAH02A06)
文摘In order to evaluate the efficiency of the automated storage/retrieval system(AS/RS)accurately,and compare different layouts of the AS/RS using mean travel time,under randomized storage conditions,an exact,geometry-based analytical model is presented.The model can be used to compute the expected single-command and dual-command travel time for a storage/retrieval(S/R)machine which can travel simultaneously horizontally and vertically as it moves along a storage aisle.The rack may be either square in time or non square in time.Additionally,the alternative layouts of the AS/RS and travel-time models are examined.Comparing with setting the I/O point at the left-lower corner of the rack,setting the I/O point at any point at the vertical edge can help enhance the efficiency of the AS/RS.
文摘For electronic piezo gauge used for testing gun chamber pressure, its internal miniature pulse-powered photoelectric invert switch cannot often be powered up normally. To solve this problem, a test system for invert switch is presented to verify the reliability of the invert switch. The test system uses complex programmable logic device (CPLD) to control data acquisition of A/D converter and data storage of external flash memory, and then transmits the acquired data to a computer for data analysis and processing. The test system can provide the required sampling frequency of the signal in high temperature, normal temperature and low temperature environments, and the reliability of the invert switch can be verified according to the signal parameters. The results show that the test system has high precision and the tested invert switch has low power consumption and high reliability.
文摘This paper describes the architecture of global distributed storage system for data grid. It focue on the management and the capability for the maximum users and maximum resources on the Internet, as well as performance and other issues.
基金supported by the National Grand Fundamental Research of China (973 Program) under Grant No. 2011CB302601the National High Technology Research and Development of China (863 Program) under GrantNo. 2013AA01A213+2 种基金the National Natural Science Foundation of China under Grant No. 60873215the Natural Science Foundation for Distinguished Young Scholars of Hunan Province under Grant No. S2010J5050Specialized Research Fund for the Doctoral Program of Higher Education under Grant No. 20124307110015
文摘To reduce the time required to complete the regeneration process of erasure codes, we propose a Tree-structured Parallel Regeneration (TPR) scheme for multiple data losses in distributed storage systems. Under the scheme, two algorithms are proposed for the construction of multiple regeneration trees, namely the edge-disjoint algorithm and edge-sharing algorithm. The edge-disjoint algorithm constructs multiple independent trees, and is simple and appropriate for environments where newcomers and their providers are distributed over a large area and have few intersections. The edge-sharing algorithm constructs multiple trees that compete to utilize the bandwidth, and make a better utilization of the bandwidth, although it needs to measure the available band-width and deal with the bandwidth changes; it is therefore difficult to implement in practical systems. The parallel regeneration for multiple data losses of TPR primarily includes two optimizations: firstly, transferring the data through the bandwidth optimized-paths in a pipe-line manner; secondly, executing data regeneration over multiple trees in parallel. To evaluate the proposal, we implement an event-based simulator and make a detailed comparison with some popular regeneration methods. The quantitative comparison results show that the use of TPR employing either the edge-disjoint algorithm or edge-sharing algorithm reduces the regeneration time significantly.
文摘First and Second Law analyses were conducted to evaluate the performance of a closed latent heat thermal energy storage (LHTES) system employing calcium chloride hexahydrate (CaCl2·6H2O). The First and the Second Laws of thermodynamics were applied to the system from viewpoint of energy and exergy analyses, respectively. The energy storage tank in the system is neither fully mixed nor fully stratified. It may be considered as semithermal stratified. Experimente that include both charging and discharging periods were performed on sunny winter days in 1996. The energy and exergy variations and the overall energy and exergy efficiencies of the closed LHTES system were calculated for the complete charging and discharging cycle of the selected fifteen clear-sky winter days. Mean energy and exergy efficiencies were found to be 55.20% and 34.83%, respectively.
基金supported by the Huawei HIRP Flagship Project(5G Networks&Big Data)the National Natural Science Foundation of China(No.61325005)the European Union EU FP7 QUICK project(No.PIRSES-GA-2013-612652)
文摘To cope with the impact of big data,it is proposed to integrate the traditionally individual computing,communications and storage systems,which are getting inevitably converged.An effective information system capacity is introduced and discussed,aimed at excavating potentials of information system under a new paradigm with more degrees of freedom.
基金the Hi-tech Research and Development Program of China,the National Natural Science Foundation of China,the Beijing Natural Science Foundation,the Fundamental Research Funds for the Central Universities,the Fund of the State Key Laboratory of Software Development Environment
文摘This paper proposes a content addres sable storage optimization method, VDeskCAS, for desktop virtualization storage based disaster backup storage system. The method implements a blocklevel storage optimization, by employing the algorithms of chunking image file into blocks, the blockffmger calculation and the block dedup li cation. A File system in Use Space (FUSE) based storage process for VDeskCAS is also introduced which optimizes current direct storage to suit our content addressable storage. An interface level modification makes our system easy to extend. Experiments on virtual desktop image files and normal files verify the effectiveness of our method and above 60% storage volume decrease is a chieved for Red Hat Enterprise Linux image files. Key words: disaster backup; desktop virtualization; storage optimization; content addressable storage
文摘Night sky cooling is explored as an alternative to the conventional cooling technologies using fossil fuels. The night sky cooling method is based on the long wave radiation of unglazed collectors to the sky at night. An evaluation of the night sky cooling system is present for a residential building in three cities of Australia, namely Alice Springs, Darwin and Melbourne. The system comprises an unglazed flat plate solar collector integrated with borehole storage. It uses night sky radiation to reduce the temperature of the ground near to the boreholes. The system was simulated with TRNSYS, a transient simulation program. The simulation results for adequately sized systems show that night sky radiation is able to reduce the coolth storage borehole temperature and the proposed system is able to meet the cooling load of the residential building simulated in three locations. Borchole lengths of 270, 318 and 106 m are required for coolth storage with 90, 260 and 14 m2 collector area for heat rejection in Alice Springs, Darwin and Melbourne, respectively. At the 20th simulation year, the proposed system is able to achieve a system cooling coefficient of performance of 2.2 in Alice Springs, and 2.8 in Darwin and Melbourne.
基金performed by key technology of networking media broadcast based on cloud computing in"China Twelfth Five-Year"Plan for Science&Technology Project(Grant No.:2013BAH65F01-2013BAH65F04)NSFC(Grant No.:61472144)+3 种基金National science and technology support plan(Grant No.:2013BAH65F03,2013BAH65F04)GDSTP(Grant No.:2013B010202004,2014A010103012)GDUPS(2011)Research Fund for the Doctoral Program of Higher Education of China(Grant No.:20120172110023)
文摘More and more embedded devices, such as mobile phones, tablet PCs and laptops, are used in every field, so huge files need to be stored or backed up into cloud storage. Optimizing the performance of cloud storage is very important for Internet development. This paper presents the performance evaluation of the open source distributed storage system, a highly available, distributed, eventually consistent object/blob store from Open Stack cloud computing components. This paper mainly focuses on the mechanism of cloud storage as well as the optimization methods to process different sized files. This work provides two major contributions through comprehensive performance evaluations. First, it provides different configurations for Open Stack Swift system and an analysis of how every component affects the performance. Second, it presents the detailed optimization methods to improve the performance in processing different sized files. The experimental results show that our method improves the performance and the structure. We give the methods to optimize the object-based cloud storage system to deploy the readily available storage system.
文摘The desire to speed up secondary storage systems has lead to the development of redundant arrays of independent disks (RAID) which incorporate redundancy utilizing erasure codes. A 'cluttered ordering' is utilized for designing an effective writing order to a RAID system. Cohen, Colboum and Froncek (2001) gave a cyclic construction of cluttered orderings for the complete graph by utilizing the notion of a 'wrapped p-labelling'. Since wrapped p-labellings as cluttered orderings for the complete graph look such as ladders, they are also called as ladder orderings. Cohen and Colboum (2004) gave a characteristic of ladder orderings. In this paper, we give an algorithm in order to generate ladder orderings.
文摘An ADS (automated dispensing system) was implemented in our hospital pharmacy in 2008 to optimize and secure the medication process. The main objective of this study was to compare the projected and the real ROI (return on investment), after seven years of use. ROI was calculated annually (from 2008 to 2015), by deducting the cost of investment (ADS buying and implementation, maintenance, repairs and ADS upgrade) from the cost saving (drugs stock reduction and decrease of pharmacy staff dedicated to global dispensing). In 2015, total costs saving (+$1,141,987) were divided between decreasing drug stock value and reduction of pharmacy staff. Total costs of investment (-$978,656) were acquisition, maintenance, repairs and an unplanned upgrade costs. Finally, the real ROI was +$163,331 after seven years of use. In 2008, projected ROI was +$410,786. The real payback period has been increased by approximately two years (six years of use, instead of four years as expected). Despite their cost, ADSs are a worthwhile investment, leading to a ROI within a few years. These economic considerations should be put into perspective with optimization of drugs stock management, greater efficiency of the global dispensing process, securitization of medication process and redeployment of pharmacy staff.
基金Project supported by the National Key Basic Research Program (973 Program) of China (No. 2007CB407206)the National Natural Science Foundation of China (No. 40621001)the Frontier Project of the Chinese Academy of Sciences (No. ISSASIP0715)
文摘Due to the growing concern about the agricultural phosphorus (P) losses pollution, an in-depth understanding of P in paddy soils of China would be helpful in providing a national perspective of the environmental impact of P cycling and fertility on China's farms. In this study, we evaluated the P storage and the P density of paddy soils in China, characterized the spatial variations of P among the subgroups of paddy soils and soil regions in China, and evaluated the P data using GIS-based analysis, which included a newly compiled 1:1 000 000 digital soil map of China, and using 1 490 soil profiles. The available and total P densities of paddy soils were 6.7 and 698.5 g m -3 , respectively. Overall in China, the total P storage within 1 m of paddy soils was estimated to be 330.2 Tg. The P density of paddy soils varied substantially with subgroups due to the different soil water regimes such as groundwater table and soil drainage. The P availability in paddy soils, especially in surface layer, was higher in high temperature and precipitation areas. Further research is needed to examine more anthropogenic impact factors, such as increasing use of chemical fertilizer.
基金supported by the National Special Basic Research Fund(Grant No.2008FY110300)National Science and Technology Support Program(Grant No.2011BAC09B07)+1 种基金National Natural Science Foundation of China(Grant No.40961003)Scientific Research Fund Project of Yunnan Education Department(Grant No.2011J018)
文摘Mountains and plateaus in Southwest China contain many subalpine and alpine wetlands, with signifieant hydroecological functions. But ungauged or poorly gauged eonditions limit the study and understanding of hydrological regimes of these wetland types. This study selects an ungauged subalpine wetland - Napahai in Northwest Yunnan, China - as a case for developing a practical approach to revealing its storage-area relationship of open water. A Trimble R8 GNSS (Global Navigation Satellites Systems) RTK (Real-time Kinematic system) and sonar fathometer were used to survey fine- resolution elevation data and generate a digital elevation model of the Napahai Wetland. Forty-four Landsat images from 1987 to 2Oll were collected, and the Normalized Difference Water Index was used to classify open water features in the area. The area of open water in Napahai was ealculated for each phase. With these data and a developed conceptual model, the storage of open water for each phase was estimated using ArcGIS tools. Both storage and area of open water showed significant intra-annual and inter-annual variations. In the rainy season, the monthly change of average storage of open water in Napahai showed about 1-2 months lag behind mean monthly rainfall. The storage-area relationship of open water was well fit by a power function equation (R2=0.91, n=44). This study indicates that if detailedelevations are available for similarly ungauged subalpine wetlands in Southwest China, researchers can use this practical approach to estimate multi- temporal areas and storages and reveal the storage- area relationship of open water in the wetlands. The study provided valuable information of this ease wetland for optimizing its hydro-ecological managements and a new method to wetland researchers and managers for the hydrological study of similarly ungauged wetland complex.
文摘A hydrogen production and conversion plant from wind power was installed in the Sotavento wind farm by Gas Natural and the Galician Government. This facility is the highest electrolysis power installed at the European level. It consists of an electrolyser of 300 kW, a piston compressor, a 1,725 Nm3 H2 storage system and an engine of 55 kW. This pilot plant is being operated by Natural Gas in order to extrapolate its behavior to that of an industrial facility capable of managing all the production of Sotavento wind farm following different strategies: balancing, peak-shaving and repowering. In this paper, preliminary results at the facility are presented. The aim of these first tests has been to describe the operation of equipment under operating conditions required in the management of wind power production, in order to understand the behavior of the different equipment and try to make them suitable for this type of applications. This paper shows the difficulty of operating these systems under the wind power requirements.
文摘The present experimental investigation covers the construction of a LHTES (latent heat thermal energy storage system), which uses NaNO_3 (sodium nitrate) as PCM (phase change material). The storage unit is filled with 300 kg of the PCM. For the heat transfer, a vertically arranged bimetallic mono tube with longitudinal fins is used. The fins increase the heat flux into/from the PCM. Thermal oil is used as a heat transfer medium, as it allows working temperature up to 400 ℃. This thermal energy storage is able to store 60 kWh of thermal energy and can be loaded with a power up to 200 kW. One part of the investigation results presented in this paper was the determination of the storable energy and the comparison with data from literature and calculations. Additionally, the melting behavior of the PCM was measured with temperature sensors located at different positions over the height of the storage unit. Finally, the entrance of the heat transfer medium was changed from the top to the bottom of the thermal energy storage unit and a different melting behavior could be detected.
基金supported by the US National Science Foundation/International Digital Library Program(Grant No.NSF/CISE/IIS-9905833).
文摘Global Memory Net (GMNet) is intended to be an effective gateway to the world cultural, historical, and heritage image collections from selected academic educational and research partners in the world. Much of these unique collections of great value to education and research are not currently accessible due to distance, form, and technical barriers. This project is to find new ways to enable users to access and exploit these significant research collections via global network. As GMNet is ending its first 5-year phase in October 2005, it has contributed substantially to the community building in digital library development by ac- commodating numerous collaborators and technical staff from various parts of the world to spend 3 to 5 months as a full-member of the GMNet team in Boston. They have come from different parts of China—such as Sichuan, Hainan, Shanghai and Xi’an; Croatia; and Hanoi, Vietnam. In addition to contribute to the overall system development and enhancement of system function- alities, they have brought valuable sample image collections of their own institutions/countries, and actually developed prototype collections as a part of GMNet. This paper describes the exciting and productive experience of the first of this visiting research group in developing the GMNet’s Version 2.0 PHP-based system under Prof. Chen’s overall supervision. It also describes both the system’s technical level structure—user/Web-based application/data, and complex functionalities with multi-collection, multi-lingual, multi-modal searching capabilities; system management capabilities; as well as provisions for user uploads and retrieval for our own projects. This Version 2.0 system is built on the Linux/Apache/PHP/MySQL platform. What is described in this paper is an actual case which has formed a base for further new development by others in the research group. It demonstrates fully the value of the synergistic collaboration among global partners for universal digital library development. More information can be found in http://www.memorynet.org/.