The rapid development and popularization of Internet technology has provided important support for the informatization reform of various industries.University books and materials have the characteristics of large quan...The rapid development and popularization of Internet technology has provided important support for the informatization reform of various industries.University books and materials have the characteristics of large quantities and difficult storage and management.Its digital storage and management platform construction can effectively realize the digital storage and real-time retrieval of books and materials,and help students and teachers to find and use books and materials more quickly.Especially in recent years,with the update of intelligent platforms and other technologies,the resource-sharing platform of university books and materials can realize more convenient book information retrieval without the limitation of time and space.This paper mainly explores the optimization path and platform construction scheme of university libraries and information management under the background of the Internet,hoping to provide some theoretical references for university library managers.展开更多
Developing technologies that can be applied simultaneously in battery thermal management(BTM)and thermal runaway(TR)mitigation is significant to improving the safety of lithium-ion battery systems.Inorganic phase chan...Developing technologies that can be applied simultaneously in battery thermal management(BTM)and thermal runaway(TR)mitigation is significant to improving the safety of lithium-ion battery systems.Inorganic phase change material(PCM)with nonflammability has the potential to achieve this dual function.This study proposed an encapsulated inorganic phase change material(EPCM)with a heat transfer enhancement for battery systems,where Na_(2)HPO_(4)·12H_(2)O was used as the core PCM encapsulated by silica and the additive of carbon nanotube(CNT)was applied to enhance the thermal conductivity.The microstructure and thermal properties of the EPCM/CNT were analyzed by a series of characterization tests.Two different incorporating methods of CNT were compared and the proper CNT adding amount was also studied.After preparation,the battery thermal management performance and TR propagation mitigation effects of EPCM/CNT were further investigated on the battery modules.The experimental results of thermal management tests showed that EPCM/CNT not only slowed down the temperature rising of the module but also improved the temperature uniformity during normal operation.The peak battery temperature decreased from 76℃to 61.2℃at 2 C discharge rate and the temperature difference was controlled below 3℃.Moreover,the results of TR propagation tests demonstrated that nonflammable EPCM/CNT with good heat absorption could work as a TR barrier,which exhibited effective mitigation on TR and TR propagation.The trigger time of three cells was successfully delayed by 129,474 and 551 s,respectively and the propagation intervals were greatly extended as well.展开更多
Thermal management is essential in our body as it affects various bodily functions,ranging from thermal discomfort to serious organ failures,as an example of the worst-case scenario.There have been extensive studies a...Thermal management is essential in our body as it affects various bodily functions,ranging from thermal discomfort to serious organ failures,as an example of the worst-case scenario.There have been extensive studies about wearable materials and devices that augment thermoregulatory functionalities in our body,employing diverse materials and systematic approaches to attaining thermal homeostasis.This paper reviews the recent progress of functional materials and devices that contribute to thermoregulatory wearables,particularly emphasizing the strategic methodology to regulate body temperature.There exist several methods to promote personal thermal management in a wearable form.For instance,we can impede heat transfer using a thermally insulating material with extremely low thermal conductivity or directly cool and heat the skin surface.Thus,we classify many studies into two branches,passive and active thermal management modes,which are further subdivided into specific strategies.Apart from discussing the strategies and their mechanisms,we also identify the weaknesses of each strategy and scrutinize its potential direction that studies should follow to make substantial contributions to future thermal regulatory wearable industries.展开更多
The development of bio-sourced materials is essential to ensuring sustainable construction;it is considered a locomotive of the green economy.Furthermore,it is an abundant material in our country,to which very little ...The development of bio-sourced materials is essential to ensuring sustainable construction;it is considered a locomotive of the green economy.Furthermore,it is an abundant material in our country,to which very little attention is being given.This work aims to valorize the waste of the trunks of banana trees to be used in construction.Firstly,the physicochemical properties of the fiber,such as the percentage of crystallization and its morphology,have been determined by X-ray diffraction tests and scanning electron microscopy to confirm the potential and the impact of the mode of drying on the quality of the banana fibers,with the purpose to promote the use of this material in construction.Secondly,the results obtained with the gypsum matrix allowed us to note a preponderant improvement in the composite’s thermal properties thanks to the variation of the banana fiber additive.Thirdly,the impact of the nature of the banana fiber distribution(either fiber mixed in matrix or fiber series model)on the flexural and compressive strengths of the composites was studied.The results obtained indicate that the insulation gain reaches up to 40%.It depends on the volume fraction and type of distribution of the banana fibers.However,the thermal inertia of the composites developed,represented by thermal diffusivity and thermal effusivity,was studied.Results indicate a gain of 40%and 25%,respectively,in terms of thermal diffusivity and thermal effusivity of the developed composites compared to plaster alone.Concerning the mechanical properties,the flexural strength depends on the percentage of the volume fraction of banana fibers used,and it can reach 20%more than the flexural strength of plaster;nevertheless,there is a significant loss in terms of the compressive strength of the studied composites.The results obtained are confirmed by the microstructure of the fiber banana.In fact,the morphology of the banana fibers was improved by the drying process.It reduces the amorphous area and improves the cellulosic crystalline surfaces,which assures good adhesion between the fiber and the matrix plaster.Finally,the dimensionless coefficient analysis was done to judge the optimal proportion of the banana fiber additive and to recommend its use even on false ceilings or walls.展开更多
The serpentine tube liquid cooling and composite PCM coupled cooling thermal management system is designed for 18650 cylindrical power batteries,with the maximum temperature and temperature difference of the power pac...The serpentine tube liquid cooling and composite PCM coupled cooling thermal management system is designed for 18650 cylindrical power batteries,with the maximum temperature and temperature difference of the power pack within the optimal temperature operating range as the target.The initial analysis of the battery pack at a 5C discharge rate,the influence of the single cell to cooling tube distance,the number of cooling tubes,inlet coolant temperature,the coolant flow rate,and other factors on the heat dissipation performance of the battery pack,initially determined a reasonable value for each design parameter.A control strategy is used to regulate the inlet flow rate and coolant temperature of the liquid cooling system in order to make full use of the latent heat of the composite PCM and reduce the pump’s energy consumption.The simulation results show that the maximum battery pack temperature of 309.8 K and the temperature difference of 4.6 K between individual cells with the control strategy are in the optimal temperature operating range of the power battery,and the utilization rate of the composite PCM is up to 90%.展开更多
In recent years,the Ministry of Agriculture has increased input in agricultural scientific research projects.As a result,the procurement amount and quantity of special materials are increasing gradually,and the manage...In recent years,the Ministry of Agriculture has increased input in agricultural scientific research projects.As a result,the procurement amount and quantity of special materials are increasing gradually,and the management of special materials becomes more standardized.In order to do well in management of special materials,the authors made exploration and thinking about further strengthening management of special materials in combination with actual conditions,including establishing regulations and systems,enhancing procurement process,strengthening requisition and safekeeping,and reinforcing general ledger management of special materials.展开更多
The work presents technologies of materials,energy and water management that can be used for sustainable buildings,reducing costs and environmental impacts.The aim was to encourage the reduction of energy consumption,...The work presents technologies of materials,energy and water management that can be used for sustainable buildings,reducing costs and environmental impacts.The aim was to encourage the reduction of energy consumption,adequate water management and more sustainable material choices in new or existing buildings.For this,a diagnosis of existing technologies and alternatives was carried out in the first stage of the work.The second stage consisted of analyzing among the technologies and alternatives diagnosed from the methodology which can be applied in a fictitious case study of housing,its implementation and maintenance and viability analyzing,finally,environmental indicators,social and economic.The results showed that the best evaluated technologies/alternatives were in Energy:ventilation and natural light;in Water Management:double-action sanitary basin,flow restrictors,aerators with constant flow,and minicistern systems;and in Materials:bamboo,wood,soil-cement brick,earth,steel frame and wood frame,aggregate with ash from rice husks,aggregate with ash from sugarcane bagasse,glass,phase change materials,aggregate with residues of construction and demolition,Portland cement and cement with blast furnace slag;which can be used in the civil construction sector,and provide socio-environmental and economic benefits,encouraging new studies and its use for public/private buildings,aid in the elaboration of public policies to reduce costs and improve the quality of buildings.展开更多
An integrated production planning and control model based on MRPⅡand JIT is put forward through analyzing the characteristics of magnetic materials manufacturing companies. Master Production Schedule with limited cap...An integrated production planning and control model based on MRPⅡand JIT is put forward through analyzing the characteristics of magnetic materials manufacturing companies. Master Production Schedule with limited capacity and operational plan in workshop level based on the basic data of flow chart are formulated by this model which applied JIT idea and based on customer order demand. Push production is adapted during execution phase combined with process flow cards. The model is helpful to reduce inventory,keep certain flexbility of production and improve continuity and equilibrium of manufacturing process.展开更多
Wearable devices with efficient thermal management and electromagnetic interference(EMI) shielding are highly desirable for improving human comfort and safety. Herein, a multifunctional wearable carbon fibers(CF) @ po...Wearable devices with efficient thermal management and electromagnetic interference(EMI) shielding are highly desirable for improving human comfort and safety. Herein, a multifunctional wearable carbon fibers(CF) @ polyaniline(PANI)/silver nanowires(Ag NWs) composites with a “branch-trunk” interlocked micro/nanostructure were achieved through "three-in-one" multi-scale design. The reasonable assembly of the three kinds of one-dimensional(1D) materials can fully exert their excellent properties i.e., the superior flexibility of CF, the robustness of PANI, and the splendid conductivity of Ag NWs. Consequently, the constructed flexible composite demonstrates enhanced mechanical properties with a tensile stress of 1.2 MPa, which was almost 6 times that of the original material. This is mainly attributed to the fact that the PNAI(branch) was firmly attached to the CF(trunk) through polydopamine(PDA), forming a robust interlocked structure. Meanwhile, the composite possesses excellent thermal insulation and heat preservation capacity owing to the synergistically low thermal conductivity and emissivity. More importantly, the conductive path of the composite established by the three 1D materials greatly improved its EMI shielding property and Joule heating performance at low applied voltage. This work paves the way for rational utilization of the intrinsic properties of 1D materials, as well as provides a promising strategy for designing wearable electromagnetic protection and thermal energy management devices.展开更多
Phase change materials have a key role for wearable thermal management,but suffer from poor water vapor permeability,low enthalpy value and weak shape stability caused by liquid phase leakage and intrinsic rigidity of...Phase change materials have a key role for wearable thermal management,but suffer from poor water vapor permeability,low enthalpy value and weak shape stability caused by liquid phase leakage and intrinsic rigidity of solid–liquid phase change materials.Herein,we report for the first time a versatile strategy for designed assembly of high-enthalpy flexible phase change nonwovens(GB-PCN)by wet-spinning hybrid grapheneboron nitride(GB)fiber and subsequent impregnating paraffins(e.g.,eicosane,octadecane).As a result,our GB-PCN exhibited an unprecedented enthalpy value of 206.0 J g^(−1),excellent thermal reliability and anti-leakage capacity,superb thermal cycling ability of 97.6%after 1000 cycles,and ultrahigh water vapor permeability(close to the cotton),outperforming the reported PCM films and fibers to date.Notably,the wearable thermal management systems based on GB-PCN for both clothing and face mask were demonstrated,which can maintain the human body at a comfortable temperature range for a significantly long time.Therefore,our results demonstrate huge potential of GB-PCN for human-wearable passive thermal management in real scenarios.展开更多
Phase change materials(PCMs)are expected to achieve dual-mode thermal management for heating and cooling Li-ion batteries(LIBs)according to real-time thermal conditions,guaranteeing the reliable operation of LIBs in b...Phase change materials(PCMs)are expected to achieve dual-mode thermal management for heating and cooling Li-ion batteries(LIBs)according to real-time thermal conditions,guaranteeing the reliable operation of LIBs in both cold and hot environments.Herein,we report a liquid metal(LM)modified polyethylene glycol/LM/boron nitride PCM,capable of dual-mode thermal managing the LIBs through photothermal effect and passive thermal conduction.Its geometrical conformation and thermal pathways fabricated through ice-template strategy are conformable to the LIB’s structure and heat-conduction characteristic.Typically,soft and deformable LMs are modified on the boron nitride surface,serving as thermal bridges to reduce the contact thermal resistance among adjacent fillers to realize high thermal conductivity of 8.8 and 7.6 W m^(−1) K^(−1) in the vertical and in-plane directions,respectively.In addition,LM with excellent photothermal performance provides the PCM with efficient battery heating capability if employing a controllable lighting system.As a proof-of-concept,this PCM is manifested to heat battery to an appropriate temperature range in a cold environment and lower the working temperature of the LIBs by more than 10℃ at high charging/discharging rate,opening opportunities for LIBs with durable working performance and evitable risk of thermal runaway.展开更多
Researchers worldwide have employed a varied array of sources to cal-culate the successful management of Construction and Demolition(C&DW).Limited research has been undertaken in the domain of Construction and Dem...Researchers worldwide have employed a varied array of sources to cal-culate the successful management of Construction and Demolition(C&DW).Limited research has been undertaken in the domain of Construction and Demoli-tion Waste Management(C&DWM)and consequently leaving a large gap in the availability of effective management techniques.Due to the limited time available for building removal and materials collection,preparing for building materials reuse at the end of life is frequently a challenging task.In this research work Con-volutional Neural Network-Long Short-Term Memory(CNN-LSTM)is proposed to predict the number of waste materials that are obtained from a building at the end of its useful life.As a result,an effective Waste Management(WM)plan has been established through SWOT analysis.The results of the study reveal that,given fundamental building characteristics,it is possible to predict the number of materials that would be collected with high precision from a building after demolition.The proposed deep learning models achieved an average R-squared value of 0.98 and a Mean Absolute Error of 18.1 and 20.14 better than existing methods such as random forest,CNN,and DBN(Data Bus Network).展开更多
On the bas is of the reality of material supply management of the coal enterprise, this paper expounds plans of material management systems based on specific IT, and indicates the deficiencies, the problems of them an...On the bas is of the reality of material supply management of the coal enterprise, this paper expounds plans of material management systems based on specific IT, and indicates the deficiencies, the problems of them and the necessity of improving them. The structure, models and data organizing schema of the material management decision support system are investigated based on a new data management technology (data warehousing technology).展开更多
Libraries are places in which all kinds of academic information are gathered, providing people with a broad platform for accessing a variety of knowledge. In addition to the knowledge in daily work, study and life, so...Libraries are places in which all kinds of academic information are gathered, providing people with a broad platform for accessing a variety of knowledge. In addition to the knowledge in daily work, study and life, some important historical materials are collected in libraries, and all of them are of important significance for studies of social development from multiple aspects. Influenced by information technology, the forms of library resources are no longer limited to books and documents, and digital resources have changed into part of the storage of library information. With the purpose of solving the problems in the current management of non-book resources, it is necessary for management personnel of libraries to actively change management model and make more scientific and sound resource management programs. Based on this point, an analysis is made by the author in this paper.展开更多
Automated performance tuning of data management systems offer various benefits such as improved performance, declined administration costs, and reduced workloads to database administrators (DBAs). Currently, DBAs tune...Automated performance tuning of data management systems offer various benefits such as improved performance, declined administration costs, and reduced workloads to database administrators (DBAs). Currently, DBAs tune the performance of database systems with a little help from the database servers. In this paper, we propose a new technique for automated performance tuning of data management systems. Firstly, we show how to use the periods of low workload time for performance improvements in the periods of high workload time. We demonstrate that extensions of a database system with materialised views and indices when a workload is low may contribute to better performance for a successive period of high workload. The paper proposes several online algorithms for continuous processing of estimated database workloads and for the discovery of the best plan for materialised view and index database extensions and of elimination of the extensions that are no longer needed. We present the results of experiments that show how the proposed automated performance tuning technique improves the overall performance of a data management system. 展开更多
In this paper, we conduct research on the modem material purchasing and the management mode under the background of informatization. Material is to maintain the normal operation of all kinds of resources integrated, t...In this paper, we conduct research on the modem material purchasing and the management mode under the background of informatization. Material is to maintain the normal operation of all kinds of resources integrated, the procurement is a significant means to ensure the enterprise supply as material purchasing is the purpose of the enterprise to obtain the value in the process of material in the production and business operation. Material purchasing constitutes the main part of enterprise cost, the success of the procurement is purchasing goods and materials to maximize value-added and it is directly related to the cost management of enterprises and the material purchasing, in order to further improve the enterprise' s buyer need to constantly enhance their own professional level that actively explore a variety of procurement mode, different procurement methods to complete the procurement, to seek for more high-quality supplies for the enterprise, at the same time, improve the production and operation of the further enterprises benefits.展开更多
The 21st century is an era of rapid development of informatization.Under the background of the development of this era,people are increasingly researching the application of information technology.The application of b...The 21st century is an era of rapid development of informatization.Under the background of the development of this era,people are increasingly researching the application of information technology.The application of big data technology is the development and application trend of an information technology formed after the rapid development of modem information technology.Big data technology has been applied to the development of many industries,including the material bidding and procurement management as well.With the aid of scientific analysis of big data,it is possible to help material procurement management to analyze the corresponding bidding procurement information,which is an important guarantee for improving its bidding procurement management capabilities.In view of this,this article has conducted special research on the application of big data in material bidding and procurement management,hoping to provide references for the application of big data technology in material bidding and procurement management with the help of the research in this article.展开更多
With the approval of the State Council, State Economicand Trade Commission, Ministry of Foreign Trade and EconomicCooperation and Ministry of Internal Trade recently issued theCircular Regarding Some Relevant Issues i...With the approval of the State Council, State Economicand Trade Commission, Ministry of Foreign Trade and EconomicCooperation and Ministry of Internal Trade recently issued theCircular Regarding Some Relevant Issues in Granting Import andExport Management Rights to Commercial and Material SupplyEnterprises. It means that work ofgranting import and exportmanagement rights has from a trial been led onto the right path ofexamination and approval. The principle of examination and ap-proval, conditions, and the procedure of reporting to a higher in-stitution shall still be in conformity with the relevant regulationsprescribed in Decree No.76 (1993) of the State Council.In November 1993, the State Council approved and trans-mitted Opinions on Experiment of Granting Import and ExportManagement Rights to Some Commercial and Material Enterprisesby State Economic and Trade Commision, Ministry of ForeignTrade and Economic Cooperation and Ministry of Internal Trade.Totaling 206 commercial (including grain and supply and sale)and material supply enterprises are put to trial and granted展开更多
Phase change materials(PCMs)can be used for efficient thermal energy harvesting,which has great potential for cost-effective thermal management and energy storage.However,the low intrinsic thermal conductivity of poly...Phase change materials(PCMs)can be used for efficient thermal energy harvesting,which has great potential for cost-effective thermal management and energy storage.However,the low intrinsic thermal conductivity of polymeric PCMs is a bottleneck for fast and efficient heat harvesting.Simultaneously,it is also a challenge to achieve a high thermal conductivity for phase change nanocomposites at low filler loading.Although constructing a three-dimensional(3D)thermally conductive network within PCMs can address these problems,the anisotropy of the 3D framework usually leads to poor thermal conductivity in the direction perpendicular to the alignment of fillers.Inspired by the interlaced structure of spider webs in nature,this study reports a new strategy for fabricating highly thermally conductive phase change composites(sw-GS/PW)with a 3D spider web(sw)-like structured graphene skeleton(GS)by hydrothermal reaction,radial freeze-casting and vacuum impregnation in paraffin wax(PW).The results show that the sw-GS hardly affected the phase transformation behavior of PW at low loading.Especially,sw-GS/PW exhibits both high cross-plane and in-plane thermal conductivity enhancements of~1260%and~840%,respectively,at an ultra-low filler loading of 2.25 vol.%.The thermal infrared results also demonstrate that sw-GS/PW possessed promising applications in battery thermal management.展开更多
文摘The rapid development and popularization of Internet technology has provided important support for the informatization reform of various industries.University books and materials have the characteristics of large quantities and difficult storage and management.Its digital storage and management platform construction can effectively realize the digital storage and real-time retrieval of books and materials,and help students and teachers to find and use books and materials more quickly.Especially in recent years,with the update of intelligent platforms and other technologies,the resource-sharing platform of university books and materials can realize more convenient book information retrieval without the limitation of time and space.This paper mainly explores the optimization path and platform construction scheme of university libraries and information management under the background of the Internet,hoping to provide some theoretical references for university library managers.
基金financially supported by the National Key Research and Development Program(Grant No.2022YFE0207400)the National Natural Science Foundation of China(Grant No.U22A20168 and 52174225)。
文摘Developing technologies that can be applied simultaneously in battery thermal management(BTM)and thermal runaway(TR)mitigation is significant to improving the safety of lithium-ion battery systems.Inorganic phase change material(PCM)with nonflammability has the potential to achieve this dual function.This study proposed an encapsulated inorganic phase change material(EPCM)with a heat transfer enhancement for battery systems,where Na_(2)HPO_(4)·12H_(2)O was used as the core PCM encapsulated by silica and the additive of carbon nanotube(CNT)was applied to enhance the thermal conductivity.The microstructure and thermal properties of the EPCM/CNT were analyzed by a series of characterization tests.Two different incorporating methods of CNT were compared and the proper CNT adding amount was also studied.After preparation,the battery thermal management performance and TR propagation mitigation effects of EPCM/CNT were further investigated on the battery modules.The experimental results of thermal management tests showed that EPCM/CNT not only slowed down the temperature rising of the module but also improved the temperature uniformity during normal operation.The peak battery temperature decreased from 76℃to 61.2℃at 2 C discharge rate and the temperature difference was controlled below 3℃.Moreover,the results of TR propagation tests demonstrated that nonflammable EPCM/CNT with good heat absorption could work as a TR barrier,which exhibited effective mitigation on TR and TR propagation.The trigger time of three cells was successfully delayed by 129,474 and 551 s,respectively and the propagation intervals were greatly extended as well.
基金supported by the National Research Foundation of Korea(NRF)Grant funded through Basic Science Research Program(2021M3H4A1A02050237).
文摘Thermal management is essential in our body as it affects various bodily functions,ranging from thermal discomfort to serious organ failures,as an example of the worst-case scenario.There have been extensive studies about wearable materials and devices that augment thermoregulatory functionalities in our body,employing diverse materials and systematic approaches to attaining thermal homeostasis.This paper reviews the recent progress of functional materials and devices that contribute to thermoregulatory wearables,particularly emphasizing the strategic methodology to regulate body temperature.There exist several methods to promote personal thermal management in a wearable form.For instance,we can impede heat transfer using a thermally insulating material with extremely low thermal conductivity or directly cool and heat the skin surface.Thus,we classify many studies into two branches,passive and active thermal management modes,which are further subdivided into specific strategies.Apart from discussing the strategies and their mechanisms,we also identify the weaknesses of each strategy and scrutinize its potential direction that studies should follow to make substantial contributions to future thermal regulatory wearable industries.
文摘The development of bio-sourced materials is essential to ensuring sustainable construction;it is considered a locomotive of the green economy.Furthermore,it is an abundant material in our country,to which very little attention is being given.This work aims to valorize the waste of the trunks of banana trees to be used in construction.Firstly,the physicochemical properties of the fiber,such as the percentage of crystallization and its morphology,have been determined by X-ray diffraction tests and scanning electron microscopy to confirm the potential and the impact of the mode of drying on the quality of the banana fibers,with the purpose to promote the use of this material in construction.Secondly,the results obtained with the gypsum matrix allowed us to note a preponderant improvement in the composite’s thermal properties thanks to the variation of the banana fiber additive.Thirdly,the impact of the nature of the banana fiber distribution(either fiber mixed in matrix or fiber series model)on the flexural and compressive strengths of the composites was studied.The results obtained indicate that the insulation gain reaches up to 40%.It depends on the volume fraction and type of distribution of the banana fibers.However,the thermal inertia of the composites developed,represented by thermal diffusivity and thermal effusivity,was studied.Results indicate a gain of 40%and 25%,respectively,in terms of thermal diffusivity and thermal effusivity of the developed composites compared to plaster alone.Concerning the mechanical properties,the flexural strength depends on the percentage of the volume fraction of banana fibers used,and it can reach 20%more than the flexural strength of plaster;nevertheless,there is a significant loss in terms of the compressive strength of the studied composites.The results obtained are confirmed by the microstructure of the fiber banana.In fact,the morphology of the banana fibers was improved by the drying process.It reduces the amorphous area and improves the cellulosic crystalline surfaces,which assures good adhesion between the fiber and the matrix plaster.Finally,the dimensionless coefficient analysis was done to judge the optimal proportion of the banana fiber additive and to recommend its use even on false ceilings or walls.
基金support provided National Natural Science Foundation of China with Grant No.51976016Natural Science Foundation of Hunan Province,China with Grant No.2020JJ4616Research Foundation of Education Bureau of Hunan Province(18B149).
文摘The serpentine tube liquid cooling and composite PCM coupled cooling thermal management system is designed for 18650 cylindrical power batteries,with the maximum temperature and temperature difference of the power pack within the optimal temperature operating range as the target.The initial analysis of the battery pack at a 5C discharge rate,the influence of the single cell to cooling tube distance,the number of cooling tubes,inlet coolant temperature,the coolant flow rate,and other factors on the heat dissipation performance of the battery pack,initially determined a reasonable value for each design parameter.A control strategy is used to regulate the inlet flow rate and coolant temperature of the liquid cooling system in order to make full use of the latent heat of the composite PCM and reduce the pump’s energy consumption.The simulation results show that the maximum battery pack temperature of 309.8 K and the temperature difference of 4.6 K between individual cells with the control strategy are in the optimal temperature operating range of the power battery,and the utilization rate of the composite PCM is up to 90%.
文摘In recent years,the Ministry of Agriculture has increased input in agricultural scientific research projects.As a result,the procurement amount and quantity of special materials are increasing gradually,and the management of special materials becomes more standardized.In order to do well in management of special materials,the authors made exploration and thinking about further strengthening management of special materials in combination with actual conditions,including establishing regulations and systems,enhancing procurement process,strengthening requisition and safekeeping,and reinforcing general ledger management of special materials.
基金Thanks to the Laboratory and Research Group ACert—Audit,Certification and Environmental Management(CNPq-UNESP/UFSCar),São Paulo State University(UNESP),University of São Paulo(ESALQ/USP)in BrazilHigher Institute of Technology of the University of Algarve(UALG)and Higher Technical Institute of the University of Lisbon(ULisboa)in PortugalNational Council for Scientific and Technological Development—CNPq and São Paulo State Research Support Foundation—FAPESP-Brazil for supporting this work.
文摘The work presents technologies of materials,energy and water management that can be used for sustainable buildings,reducing costs and environmental impacts.The aim was to encourage the reduction of energy consumption,adequate water management and more sustainable material choices in new or existing buildings.For this,a diagnosis of existing technologies and alternatives was carried out in the first stage of the work.The second stage consisted of analyzing among the technologies and alternatives diagnosed from the methodology which can be applied in a fictitious case study of housing,its implementation and maintenance and viability analyzing,finally,environmental indicators,social and economic.The results showed that the best evaluated technologies/alternatives were in Energy:ventilation and natural light;in Water Management:double-action sanitary basin,flow restrictors,aerators with constant flow,and minicistern systems;and in Materials:bamboo,wood,soil-cement brick,earth,steel frame and wood frame,aggregate with ash from rice husks,aggregate with ash from sugarcane bagasse,glass,phase change materials,aggregate with residues of construction and demolition,Portland cement and cement with blast furnace slag;which can be used in the civil construction sector,and provide socio-environmental and economic benefits,encouraging new studies and its use for public/private buildings,aid in the elaboration of public policies to reduce costs and improve the quality of buildings.
基金supported by Ministry of Education Social Science and Humanities Fund(12YJA630187)SHANNXI Social Science Fund(10Q067)High Education Research Fund of Northwestern Polytechnical University(2014)
文摘An integrated production planning and control model based on MRPⅡand JIT is put forward through analyzing the characteristics of magnetic materials manufacturing companies. Master Production Schedule with limited capacity and operational plan in workshop level based on the basic data of flow chart are formulated by this model which applied JIT idea and based on customer order demand. Push production is adapted during execution phase combined with process flow cards. The model is helpful to reduce inventory,keep certain flexbility of production and improve continuity and equilibrium of manufacturing process.
基金supported by the National Nature Science Foundation of China (Nos. 51971111, 52273247)the facilities in the Center for Microscopy and Analysis at Nanjing University of Aeronautics and Astronautics and the Fund of Prospective Layout of Scientific Research for NUAA (Nanjing University of Aeronautics and Astronautics (No. ILA220461A22)。
文摘Wearable devices with efficient thermal management and electromagnetic interference(EMI) shielding are highly desirable for improving human comfort and safety. Herein, a multifunctional wearable carbon fibers(CF) @ polyaniline(PANI)/silver nanowires(Ag NWs) composites with a “branch-trunk” interlocked micro/nanostructure were achieved through "three-in-one" multi-scale design. The reasonable assembly of the three kinds of one-dimensional(1D) materials can fully exert their excellent properties i.e., the superior flexibility of CF, the robustness of PANI, and the splendid conductivity of Ag NWs. Consequently, the constructed flexible composite demonstrates enhanced mechanical properties with a tensile stress of 1.2 MPa, which was almost 6 times that of the original material. This is mainly attributed to the fact that the PNAI(branch) was firmly attached to the CF(trunk) through polydopamine(PDA), forming a robust interlocked structure. Meanwhile, the composite possesses excellent thermal insulation and heat preservation capacity owing to the synergistically low thermal conductivity and emissivity. More importantly, the conductive path of the composite established by the three 1D materials greatly improved its EMI shielding property and Joule heating performance at low applied voltage. This work paves the way for rational utilization of the intrinsic properties of 1D materials, as well as provides a promising strategy for designing wearable electromagnetic protection and thermal energy management devices.
基金supported by the National Natural Science Foundation of China(Nos.21903082,22003065,22125903,51872283,22075279,21805273,22273100)Dalian Innovation Support Plan for High Level Talents(2019RT09)+3 种基金Dalian National Laboratory For Clean Energy(DNL),CAS,DNL Cooperation Fund,CAS(DNL201912,DNL201915,DNL202016,DNL202019)DICP(DICP I2020032,DICP I202036,I202218)The Joint Fund of the Yulin University and the Dalian National Laboratory for Clean Energy(YLU-DNL Fund 2021002,YLU-DNL 2021007,YLU-DNL 2021009)Q.Shi would like to thank Dalian Outstanding Young Scientific Talent Program(Grant 2019RJ10).
文摘Phase change materials have a key role for wearable thermal management,but suffer from poor water vapor permeability,low enthalpy value and weak shape stability caused by liquid phase leakage and intrinsic rigidity of solid–liquid phase change materials.Herein,we report for the first time a versatile strategy for designed assembly of high-enthalpy flexible phase change nonwovens(GB-PCN)by wet-spinning hybrid grapheneboron nitride(GB)fiber and subsequent impregnating paraffins(e.g.,eicosane,octadecane).As a result,our GB-PCN exhibited an unprecedented enthalpy value of 206.0 J g^(−1),excellent thermal reliability and anti-leakage capacity,superb thermal cycling ability of 97.6%after 1000 cycles,and ultrahigh water vapor permeability(close to the cotton),outperforming the reported PCM films and fibers to date.Notably,the wearable thermal management systems based on GB-PCN for both clothing and face mask were demonstrated,which can maintain the human body at a comfortable temperature range for a significantly long time.Therefore,our results demonstrate huge potential of GB-PCN for human-wearable passive thermal management in real scenarios.
基金This work was financially supported by the National Natural Science Foundation of China(No.52103091)the Natural Science Foundation of Jiangsu Province(No.BK20200501)the State Key Laboratory of Polymer Materials Engineering(No.sklpme2022-3-15).
文摘Phase change materials(PCMs)are expected to achieve dual-mode thermal management for heating and cooling Li-ion batteries(LIBs)according to real-time thermal conditions,guaranteeing the reliable operation of LIBs in both cold and hot environments.Herein,we report a liquid metal(LM)modified polyethylene glycol/LM/boron nitride PCM,capable of dual-mode thermal managing the LIBs through photothermal effect and passive thermal conduction.Its geometrical conformation and thermal pathways fabricated through ice-template strategy are conformable to the LIB’s structure and heat-conduction characteristic.Typically,soft and deformable LMs are modified on the boron nitride surface,serving as thermal bridges to reduce the contact thermal resistance among adjacent fillers to realize high thermal conductivity of 8.8 and 7.6 W m^(−1) K^(−1) in the vertical and in-plane directions,respectively.In addition,LM with excellent photothermal performance provides the PCM with efficient battery heating capability if employing a controllable lighting system.As a proof-of-concept,this PCM is manifested to heat battery to an appropriate temperature range in a cold environment and lower the working temperature of the LIBs by more than 10℃ at high charging/discharging rate,opening opportunities for LIBs with durable working performance and evitable risk of thermal runaway.
文摘Researchers worldwide have employed a varied array of sources to cal-culate the successful management of Construction and Demolition(C&DW).Limited research has been undertaken in the domain of Construction and Demoli-tion Waste Management(C&DWM)and consequently leaving a large gap in the availability of effective management techniques.Due to the limited time available for building removal and materials collection,preparing for building materials reuse at the end of life is frequently a challenging task.In this research work Con-volutional Neural Network-Long Short-Term Memory(CNN-LSTM)is proposed to predict the number of waste materials that are obtained from a building at the end of its useful life.As a result,an effective Waste Management(WM)plan has been established through SWOT analysis.The results of the study reveal that,given fundamental building characteristics,it is possible to predict the number of materials that would be collected with high precision from a building after demolition.The proposed deep learning models achieved an average R-squared value of 0.98 and a Mean Absolute Error of 18.1 and 20.14 better than existing methods such as random forest,CNN,and DBN(Data Bus Network).
文摘On the bas is of the reality of material supply management of the coal enterprise, this paper expounds plans of material management systems based on specific IT, and indicates the deficiencies, the problems of them and the necessity of improving them. The structure, models and data organizing schema of the material management decision support system are investigated based on a new data management technology (data warehousing technology).
文摘Libraries are places in which all kinds of academic information are gathered, providing people with a broad platform for accessing a variety of knowledge. In addition to the knowledge in daily work, study and life, some important historical materials are collected in libraries, and all of them are of important significance for studies of social development from multiple aspects. Influenced by information technology, the forms of library resources are no longer limited to books and documents, and digital resources have changed into part of the storage of library information. With the purpose of solving the problems in the current management of non-book resources, it is necessary for management personnel of libraries to actively change management model and make more scientific and sound resource management programs. Based on this point, an analysis is made by the author in this paper.
文摘Automated performance tuning of data management systems offer various benefits such as improved performance, declined administration costs, and reduced workloads to database administrators (DBAs). Currently, DBAs tune the performance of database systems with a little help from the database servers. In this paper, we propose a new technique for automated performance tuning of data management systems. Firstly, we show how to use the periods of low workload time for performance improvements in the periods of high workload time. We demonstrate that extensions of a database system with materialised views and indices when a workload is low may contribute to better performance for a successive period of high workload. The paper proposes several online algorithms for continuous processing of estimated database workloads and for the discovery of the best plan for materialised view and index database extensions and of elimination of the extensions that are no longer needed. We present the results of experiments that show how the proposed automated performance tuning technique improves the overall performance of a data management system.
文摘In this paper, we conduct research on the modem material purchasing and the management mode under the background of informatization. Material is to maintain the normal operation of all kinds of resources integrated, the procurement is a significant means to ensure the enterprise supply as material purchasing is the purpose of the enterprise to obtain the value in the process of material in the production and business operation. Material purchasing constitutes the main part of enterprise cost, the success of the procurement is purchasing goods and materials to maximize value-added and it is directly related to the cost management of enterprises and the material purchasing, in order to further improve the enterprise' s buyer need to constantly enhance their own professional level that actively explore a variety of procurement mode, different procurement methods to complete the procurement, to seek for more high-quality supplies for the enterprise, at the same time, improve the production and operation of the further enterprises benefits.
文摘The 21st century is an era of rapid development of informatization.Under the background of the development of this era,people are increasingly researching the application of information technology.The application of big data technology is the development and application trend of an information technology formed after the rapid development of modem information technology.Big data technology has been applied to the development of many industries,including the material bidding and procurement management as well.With the aid of scientific analysis of big data,it is possible to help material procurement management to analyze the corresponding bidding procurement information,which is an important guarantee for improving its bidding procurement management capabilities.In view of this,this article has conducted special research on the application of big data in material bidding and procurement management,hoping to provide references for the application of big data technology in material bidding and procurement management with the help of the research in this article.
文摘With the approval of the State Council, State Economicand Trade Commission, Ministry of Foreign Trade and EconomicCooperation and Ministry of Internal Trade recently issued theCircular Regarding Some Relevant Issues in Granting Import andExport Management Rights to Commercial and Material SupplyEnterprises. It means that work ofgranting import and exportmanagement rights has from a trial been led onto the right path ofexamination and approval. The principle of examination and ap-proval, conditions, and the procedure of reporting to a higher in-stitution shall still be in conformity with the relevant regulationsprescribed in Decree No.76 (1993) of the State Council.In November 1993, the State Council approved and trans-mitted Opinions on Experiment of Granting Import and ExportManagement Rights to Some Commercial and Material Enterprisesby State Economic and Trade Commision, Ministry of ForeignTrade and Economic Cooperation and Ministry of Internal Trade.Totaling 206 commercial (including grain and supply and sale)and material supply enterprises are put to trial and granted
基金This work was supported by the National Natural Science Foundation of China(Numbers:U19A20105,51877132).
文摘Phase change materials(PCMs)can be used for efficient thermal energy harvesting,which has great potential for cost-effective thermal management and energy storage.However,the low intrinsic thermal conductivity of polymeric PCMs is a bottleneck for fast and efficient heat harvesting.Simultaneously,it is also a challenge to achieve a high thermal conductivity for phase change nanocomposites at low filler loading.Although constructing a three-dimensional(3D)thermally conductive network within PCMs can address these problems,the anisotropy of the 3D framework usually leads to poor thermal conductivity in the direction perpendicular to the alignment of fillers.Inspired by the interlaced structure of spider webs in nature,this study reports a new strategy for fabricating highly thermally conductive phase change composites(sw-GS/PW)with a 3D spider web(sw)-like structured graphene skeleton(GS)by hydrothermal reaction,radial freeze-casting and vacuum impregnation in paraffin wax(PW).The results show that the sw-GS hardly affected the phase transformation behavior of PW at low loading.Especially,sw-GS/PW exhibits both high cross-plane and in-plane thermal conductivity enhancements of~1260%and~840%,respectively,at an ultra-low filler loading of 2.25 vol.%.The thermal infrared results also demonstrate that sw-GS/PW possessed promising applications in battery thermal management.