Transferring patients with critical illnesses from general wards to intensive care units (ICUs) is a crucial and time-sensitive process. This article presents strategies for improving the efficiency of patient transfe...Transferring patients with critical illnesses from general wards to intensive care units (ICUs) is a crucial and time-sensitive process. This article presents strategies for improving the efficiency of patient transfers, particularly in hospitals where intensive care units are located in buildings separate from general wards. Patient transfers comprise several steps: physicians issue orders, relatives are notified, equipment is prepared, and medical staff coordinate. We identified three factors that influence transfer time: preparation time for bed transfer, time required for shift handovers, and time required for between-ward patient movement. Unfamiliarity with transfer routes and long elevator wait times were factors that also influenced transfer time. The following strategies were proposed: develop a standardized material checklist, design key notes for patient transfers, and optimize transfer routes. These strategies reduced transfer times by 40% to 43%. This study demonstrates that by addressing logistical challenges and streamlining relevant procedures, hospitals can enhance safety and quality of care during patient transfers.展开更多
Gas hydrates formation and dissociation processes inside porous media are always accompanied by water transfer behavior, which is similar to the water behavior of ice freezing and thawing processes. These processes ha...Gas hydrates formation and dissociation processes inside porous media are always accompanied by water transfer behavior, which is similar to the water behavior of ice freezing and thawing processes. These processes have been studied by many researchers, but all the studies are so far on the water transfer characteristics outside porous media and the water transfer characteristics inside porous media have been little known. In this study, in order to study the water transfer characteristics inside porous media during methane hydrate formation and dissociation processes, a novel apparatus with three pF-meter sensors which can detect water content changes inside porous media was applied. It was experimentally observed that methane hydrate formation processes were accompanied by water transfer from bottom to top inside porous media, however, the water behavior during hydrate dissociation processes was abnormal, for which more studies are needed to find out the real reason in our future work.展开更多
A 3-D mathematical model considering turbulence phenomena has been established based on a computational fluid dynamics technique, so called 3-D SOLA-VOF (Solution Algorithm-Volume of Fluid), to simulate the fluid flow...A 3-D mathematical model considering turbulence phenomena has been established based on a computational fluid dynamics technique, so called 3-D SOLA-VOF (Solution Algorithm-Volume of Fluid), to simulate the fluid flow of mold filling process of die casting. In addition, the mathematical model for simulating the heat transfer in die casting process has also been established. The computation program has been developed by the authors with the finite difference method (FDM) recently. As verification, the mold filling process of a S-shaped die casting has been simulated and the simulation results coincide with that of the benchmark test. Finally, as a practical application, the gating design of a motorcycle component was modified by the mold filling simulation and the dies design of another motorcycle component was optimized by the heat transfer simulation. All the optimized designs were verified by the production practice.展开更多
Nonylphenol(NP)residues,as a typical endocrine disrupting chemical(EDC),frequently exist in sewage,surface water,groundwater and even drinking water,which poses a serious threat to human health due to its bioaccumulat...Nonylphenol(NP)residues,as a typical endocrine disrupting chemical(EDC),frequently exist in sewage,surface water,groundwater and even drinking water,which poses a serious threat to human health due to its bioaccumulation.In order to remove NP,a series of MIL-100(Fe)/Zn Fe_(2)O_(4)/flake-like porous carbon nitride(MIL/ZC)was synthesized through in-situ synthesis at room temperature.High performance of ternary MIL/ZC is used to degrade NP under visible light irradiation.The results show that 30MIL/ZC2(20 wt.%Zn Fe_(2)O_(4))ternary composite had the best photocatalytic activity(99.84%)when the dosage was 30 mg.Further mechanism analysis shows that the excellent photocatalytic activity of 30MIL/ZC2could be ascribed to the double charge transfer process between flake-like porous carbon nitride(PCN)and other catalysts in the ternary heterojunction,and the separation of photogenerated electron-hole pairs was more effective.In addition,the 30MIL/ZC2 also showed high stability after five cycles of the photodegradation reaction.Furthermore,the active substance(·O_(2)^(-))was considered to be the main active substance in the NP degradation process.Based on the research results,the possible photocatalytic reaction mechanism of 30MIL/ZC2ternary composite was proposed and discussed in detail.展开更多
Improving the seepage of leaching solution in the ore body and strengthening the mass transfer process of rare earth ions during in-situ leaching are two critical methods to improve the leaching efficiency of rare ear...Improving the seepage of leaching solution in the ore body and strengthening the mass transfer process of rare earth ions during in-situ leaching are two critical methods to improve the leaching efficiency of rare earth.In this study,2 wt%MgSO_(4)solution was used for the indoor simulated column leaching experiment on rare earth samples and an electric field was applied at both ends of the samples.Then the effects of different intensities,initial application time and duration of the electric field on the rare earth leaching system and its mechanism were investigated.The results show that compared with the single MgSO_(4)solution leaching,applying an electric field with a strength of 6 V/cm can save the leaching time of 30 min and increase the flow velocity of the rare earth leachate by 26.98%.Under the optimal conditions of applying an electric field with a strength of 6 V/cm for 20 min to the leaching system after10 min of the rare earth leachate flowing out,the leaching efficiency of sample increases from 81.20% to 86.05% with the increase of 4.85%.The mechanism analysis shows that when a direct current electric field is applied to the rare earth leaching system,rare earth ions rapidly change from disorderly movement with the seepage into faster and directional movement.In addition,the seepage of the leaching solution is also improved due to the increase of the cross-sectional area of the seepage channel,the polarized water molecules migrate directionally by force from the negative pole,and the movement of the hydrogen is generated by the electrolytic water.More impo rtantly,based on the principle of in-situ leaching process,the layout of injection holes and deflector holes in this process provides a natural site for the electrode layout of the electric field.With the simple equipme nt and the ope ration,the rare earth leaching process with the applied electric field has high feasibility in industrial application.展开更多
The objective of this study is to predict grain size and heat transfer coefficient at the metal-die interface during high pressure die casting process and solidification of the magnesium alloy AM60. Multiple runs of t...The objective of this study is to predict grain size and heat transfer coefficient at the metal-die interface during high pressure die casting process and solidification of the magnesium alloy AM60. Multiple runs of the commercial casting simulation package, ProCASTTM, were used to model the mold filling and solidification events employing a range of interfacial heat transfer coefficient values. The simulation results were used to estimate the centerline cooling curve at various locations through the casting. The centerline cooling curves, together with the die temperature and the thermodynamic properties of the alloy, were then used as inputs to compute the solution to the Stefan problem of a moving phase boundary, thereby providing the through-thickness cooling curves at each chosen location of the casting, Finally, the local cooling rate was used to calculate the resulting grain size via previously established relationships. The effects of die temperature, filling time and heat transfer coefficient on the grain structure in skin region and core region were quantitatively characterized. It was observed that the grain size of skin region strongly depends on above three factors whereas the grain size of core region shows dependence on the interracial heat transfer coefficient and thickness of the samples. The grain size distribution from surface to center was estimated from the relationship between grain size and the predicted cooling rate. The prediction of grain size matches well with experimental results. A comparison of the predicted and experimentally determined grain size profiles enables the determination of the apparent interracial heat transfer coefficient for different locations.展开更多
This paper investigates the thermal-coupled effect across the wall and the optimal heat transfer region of the wall for enhancing the energy saving effect of dividing wall column (DWC), and also studies the effects of...This paper investigates the thermal-coupled effect across the wall and the optimal heat transfer region of the wall for enhancing the energy saving effect of dividing wall column (DWC), and also studies the effects of feed thermal condition (q) and middle component composition of feed (cB) on the heat transfer process, the optimal heat transfer region, and the maximum heat transfer quantity across the wall. The simulation results show that the maximum heat transfer quantity across the wall and the potential for energy saving increase with the increase of q, while with the limitation of temperature difference across the wall, the beneficial heat transfer effect between certain range of stages, which are involved in the optimal heat transfer region, cannot be realized completely for a specific value of q. Besides, compared with q, a changing cB does not change the degree of realizing the beneficial heat transfer effect, but can bring about the variation of liquid split ratio (RL) and vapor split ratio (Rv). Thus, for achieving a maximum energy-saving effect of DWC, different q and cB need to find its own corresponding suitable heat transfer process across the wall.展开更多
Fault diagnosis is an important measure to ensure the safety of production, and all kinds of fault diagnosis methods are of importance in actual production process. However, the complexity and uncertainty of productio...Fault diagnosis is an important measure to ensure the safety of production, and all kinds of fault diagnosis methods are of importance in actual production process. However, the complexity and uncertainty of production process often lead to the changes of data distribution and the emergence of new fault classes, and the number of the new fault classes is unpredictable. The reconstruction of the fault diagnosis model and the identification of new fault classes have become core issues under the circumstances. This paper presents a fault diagnosis method based on model transfer learning and the main contributions of the paper are as follows: 1) An incremental model transfer fault diagnosis method is proposed to reconstruct the new process diagnosis model. 2) Breaking the limit of existing method that the new process can only have one more class of faults than the old process, this method can identify M faults more in the new process with the thought of incremental learning. 3) The method offers a solution to a series of problems caused by the increase of fault classes. Experiments based on Tennessee-Eastman process and ore grinding classification process demonstrate the effectiveness and the feasibility of the method.展开更多
In this work, the in-situ TiC panicles reinforced composite coating was prepared by plasma transferred arc process on the surface of Q235 steel. Microstructures, phase composition and wear property of the coating were...In this work, the in-situ TiC panicles reinforced composite coating was prepared by plasma transferred arc process on the surface of Q235 steel. Microstructures, phase composition and wear property of the coating were investigated. The results showed that the composite coating consisted mainly of T-Ni, TiC, Cr23C6, Cr7C3, Ni3Si, CrB, Cr5B3 and FeNi3 phases, and was characterized by fine TiC panicles embedded in Ni matrix. The wear resistance of composite coating was significantly improved compared with that of the steel substrate. The wear volume loss of the substrate was 443 mm3, which was about 9 times as that of in-situ TiC particles reinforced composite coating （49 mm3 ）. It is mainly attributed to the presence of chromium carbide particles and in-situ TiC particles and their favorable combination with Ni matrix.展开更多
According to heat transfer principle and the process of solving engineering problems by finite element method, examples were given to demonstrate how finite element analysis can be used to describe transient heat tran...According to heat transfer principle and the process of solving engineering problems by finite element method, examples were given to demonstrate how finite element analysis can be used to describe transient heat transfer through fabrics. Details were given to describe how conduction and convection affect temperature distribution and heat loss during heat transfer processes by taking advantage of the quick calculation of FEA software MSC.Marc. Experimental results show good agreement with the theoretical results.展开更多
A pioneering glass-compatible transparent temperature alarm system self-powered by luminescent solar concentrators(LSCs) is reported.Single green-emitted organic manganese halides(OMHs) of PEA_(2)MnBr_(2)I_(2),which h...A pioneering glass-compatible transparent temperature alarm system self-powered by luminescent solar concentrators(LSCs) is reported.Single green-emitted organic manganese halides(OMHs) of PEA_(2)MnBr_(2)I_(2),which has a unique temperature-dependent backward energy transfer process from selftrapped state to^(4)T_(1)energy level of Mn,is used for triggering the temperature alarm.The LSC with redemitted CsPbI_(3)perovskite-polymer composite films on the glass substrate is used for power supply.The spectrally separated nature between the green-emitted OMHs for temperature alarm and red-emitted CsPbI3in LSC for power supply allows for probing the signal light of temperature-responsive OMHs without the interference of LSCs,making it possible to calibrate the temperature visually just by a self-powered brightness detection circuit with LED indicators.Taking advantage of LSC without hot spot effects plaguing the solar cells,as-prepared temperature alarm system can operate well on both sunny and cloudy day.展开更多
The concept of process intensification(PI) has absorbed diverse definitions and stays true to the mission—'do more with less', which is an approach purposed by chemical engineers to solve the global energy &a...The concept of process intensification(PI) has absorbed diverse definitions and stays true to the mission—'do more with less', which is an approach purposed by chemical engineers to solve the global energy & environment problems. To date, the focus of PI has been on processes mainly involving vapor/liquid systems. Based on the fundamental principles of vapor–liquid mass transfer process like distillation and absorption, there are three strategies to intensify interphase mass transfer: enhancing the overall driving force, improving the mass transfer coefficient and enlarging the vapor–liquid interfacial area. More specifically, this article herein provides an overview of various technologies to strengthen the vapor–liquid mass transfer, including application of external fields, addition of third substances, micro-chemical technology and usage of solid foam, with the objective to contribute to the future developments and potential applications of PI in scientific research and industrial sectors.展开更多
Based on investigation data of PHC content in Jiaozhou Bay,China from 1979 to 1983,the seasonal variations of PHC content and monthly changes of precipitation in Jiaozhou Bay were analyzed. The results showed that see...Based on investigation data of PHC content in Jiaozhou Bay,China from 1979 to 1983,the seasonal variations of PHC content and monthly changes of precipitation in Jiaozhou Bay were analyzed. The results showed that seen from the spatial and temporal distribution,the seasonal variation of PHC content in the surface water of Jiaozhou Bay was based on the flow of the rivers as well as human activity,so PHC content in the rivers depended on the flow of the rivers and human activity,and the peaks and valleys of PHC content appeared in various seasons. The seasonal variation of PHC content in the surface water of Jiaozhou Bay depended on its land transfer process. The land transfer process was composed of use of PHC by mankind,deposition of PHC in soil and on the earth＇s surface,and transportation of PHC to offshore waters of sea by rivers and surface runoff. PHC content depended on mankind during the process from being used to entering soil and on precipitation during the process of being transported from soil to ocean.展开更多
The energy-transfer process between sodium (omega-[2-(alpha -naphthyl)ethoxy]undecanoate (FP-)* and sodium omega -9-anthrylmethyl glutarate (AFP(-)) is accelerated by the formation of ESAg when cetyltrimethylammonium ...The energy-transfer process between sodium (omega-[2-(alpha -naphthyl)ethoxy]undecanoate (FP-)* and sodium omega -9-anthrylmethyl glutarate (AFP(-)) is accelerated by the formation of ESAg when cetyltrimethylammonium chloride (S16(+)) has been added to the solvent system of FP-* and AFP(-). This result is yet another evidence for the formation of ESAg.展开更多
The prompt supercritical process of a nuclear reactor with temperature feedback and initial power as well as heat transfer with a big step reactivity (ρ0>β) is analyzed in this paper. Considering the effect of he...The prompt supercritical process of a nuclear reactor with temperature feedback and initial power as well as heat transfer with a big step reactivity (ρ0>β) is analyzed in this paper. Considering the effect of heat transfer on temperature of the reactor, a new model is set up. For any initial power, the variations of output power and reactivity with time are obtained by numerical method. The effects of the big inserted step reactivity and initial power on the prompt supercritical process are analyzed and discussed. It was found that the effect of heat transfer on the output power and reactivity can be neglected under any initial power, and the output power obtained by the adiabatic model is basically in accordance with that by the model of this paper, and the analytical solution can be adopted. The results provide a theoretical base for safety analysis and operation management of a power reactor.展开更多
Based on the investigation data of PHC content in Jiaozhou Bay,China during 1980-1981,the vertical distribution of PHC content in the water of Jiaozhou Bay was analyzed.The results showed that from 1980 to 1981,the ve...Based on the investigation data of PHC content in Jiaozhou Bay,China during 1980-1981,the vertical distribution of PHC content in the water of Jiaozhou Bay was analyzed.The results showed that from 1980 to 1981,the vertical distribution of PHC content in the water of Jiaozhou Bay depended on the water transfer process of PHC.During the water transfer process of PHC,PHC was input from pollution sources into the surface water of the bay firstly,and then it settled to the bottom.The horizontal distribution trends of PHC content in the surface and bottom water,the changes of PHC content in the surface and bottom water,and the vertical changes of PHC content showed that the settlement of PHC was fast and was consistent with PHC content.PHC accumulated at the bottom after continuous settlement of PHC,which revealed the water transfer process of PHC in Jiaozhou Bay.展开更多
In order to study water transfer characteristics inside non-saturated media during methane hydrate formation and dissociation processes,water changes on the top,middle and bottom locations of experimental media during...In order to study water transfer characteristics inside non-saturated media during methane hydrate formation and dissociation processes,water changes on the top,middle and bottom locations of experimental media during the reaction processes were continuously followed with a novel apparatus with three pF-meter sensors.Coarse sand,fine sand and loess were chosen as experimental media.It was experimentally observed that methane hydrate was easier formed inside coarse sand and fine sand than inside loess.Methane hydrate formation configuration and water transfer characteristics during methane hydrate formation processes were very different among the different non-saturated media,which were important for understanding methane hydrate formation and dissociation mechanism inside sediments in nature.展开更多
In order to understand the relation between microstructure of superalloypowders and its solidification progress, the processing parameters are optimized during plasmarotating electrode processing (PREP). It was predic...In order to understand the relation between microstructure of superalloypowders and its solidification progress, the processing parameters are optimized during plasmarotating electrode processing (PREP). It was predicted from the results that the droplet velocities,droplet temperature, and fractional solidification with flight time about FGH95 superalloy droplethave been carried out based on Newtonian heat transfer formulation coupled with the classicalheterogeneous nucleation and the specific solidification process. It has been found that the dropletdynamic and thermal behavior is strongly affected by the distribution of droplet diameters, theproportion of cooling atmosphere, but is relatively unaffected by the droplet superheat.展开更多
Knowledge transfer model of software process improvement (SPI) and the conceptual framework of influencing factors are established. The model includes five elements which are knowledge of transfer, sources of knowledg...Knowledge transfer model of software process improvement (SPI) and the conceptual framework of influencing factors are established. The model includes five elements which are knowledge of transfer, sources of knowledge, recipients of knowledge, relationship of transfer parties, and the environment of transfer. The conceptual framework includes ten key factors which are ambiguity, systematism, transfer willingness, capacity of impartation, capacity of absorption, incen-tive mechanism, culture, technical support, trust and knowledge distance. The research hypothesis is put forward. Em-pirical study concludes that the trust relationship among SPI staffs has the greatest influence on knowledge transfer, and organizational incentive mechanism can produce positive effect to knowledge transfer of SPI. Finally, some sug-gestions are put forward to improve the knowledge transfer of SPI: establishing a rational incentive mechanism, exe-cuting some necessary training to transfer parties and using software benchmarking.展开更多
Flexible transfer line(FTL)is now widely used in ma ny manufacturing domains to realize efficiently,high quantity and economic prod uction.These manufacturing domains include automobile,tractor,internal-combu stion en...Flexible transfer line(FTL)is now widely used in ma ny manufacturing domains to realize efficiently,high quantity and economic prod uction.These manufacturing domains include automobile,tractor,internal-combu stion engine,and so on.In today’s competitive business environment,it is vit ally important for machine tool manufacturers to design flexible transfer line m ore effectively and efficiently according to a wider variety of customer demand s.This paper proposes an approach to a bidding-based flexible transfer line sc hematic design system.By analyzing manual FTL design process,the architecture o f flexible transfer line schematic design system(FTLSDS)is established.The syst em consists:of four processes:part feature modeling,process planning,FTL fac i lity layout and FTL evaluation. For FTL schematic design.a five-level proces s planning strategy named hierarchical process planning method is proposed.This method includes selection of manufacturing feature machining operation;part se t-up planning,feature sequencing,operation sequencing and process plan genera ting.The major decision relies on setup planning.According to the proceeding o f the hierarchical process planning,the structure of reasoning is proposed base d on blackboard.Under this paradigm,a cooperative effort between a hybrid coll ection of knowledge sources is possible.Total reasoning task can be divided int o some subtasks,and recursive-reasoning system is formed.It is convenient for process planning with step-by-step solution.Meanwhile,the blackboard is use d as the global data exchange area during all reasoning process.By using modula r technology,special purpose machine tools can be designed more efficiently and rapidly.The framework of machine modular design system to support machine requ irement design for FTL is established.By synthesizing the FTL evaluation criter ia.five evaluation criteria of flexible transfer 1ine schematic design are take n into account.An exampie is supplied to demonstrate and verify the validity an d feasibility of flexible transfer line schematic design approach.展开更多
文摘Transferring patients with critical illnesses from general wards to intensive care units (ICUs) is a crucial and time-sensitive process. This article presents strategies for improving the efficiency of patient transfers, particularly in hospitals where intensive care units are located in buildings separate from general wards. Patient transfers comprise several steps: physicians issue orders, relatives are notified, equipment is prepared, and medical staff coordinate. We identified three factors that influence transfer time: preparation time for bed transfer, time required for shift handovers, and time required for between-ward patient movement. Unfamiliarity with transfer routes and long elevator wait times were factors that also influenced transfer time. The following strategies were proposed: develop a standardized material checklist, design key notes for patient transfers, and optimize transfer routes. These strategies reduced transfer times by 40% to 43%. This study demonstrates that by addressing logistical challenges and streamlining relevant procedures, hospitals can enhance safety and quality of care during patient transfers.
基金financially supported by the CAS Knowledge Innovation Key Project (Grant No. KZCX2-YW- 330)the National Science Fund FosteringTalents in Basic Research to Glaciology and Geocryology (Grant No. J0630966)
文摘Gas hydrates formation and dissociation processes inside porous media are always accompanied by water transfer behavior, which is similar to the water behavior of ice freezing and thawing processes. These processes have been studied by many researchers, but all the studies are so far on the water transfer characteristics outside porous media and the water transfer characteristics inside porous media have been little known. In this study, in order to study the water transfer characteristics inside porous media during methane hydrate formation and dissociation processes, a novel apparatus with three pF-meter sensors which can detect water content changes inside porous media was applied. It was experimentally observed that methane hydrate formation processes were accompanied by water transfer from bottom to top inside porous media, however, the water behavior during hydrate dissociation processes was abnormal, for which more studies are needed to find out the real reason in our future work.
文摘A 3-D mathematical model considering turbulence phenomena has been established based on a computational fluid dynamics technique, so called 3-D SOLA-VOF (Solution Algorithm-Volume of Fluid), to simulate the fluid flow of mold filling process of die casting. In addition, the mathematical model for simulating the heat transfer in die casting process has also been established. The computation program has been developed by the authors with the finite difference method (FDM) recently. As verification, the mold filling process of a S-shaped die casting has been simulated and the simulation results coincide with that of the benchmark test. Finally, as a practical application, the gating design of a motorcycle component was modified by the mold filling simulation and the dies design of another motorcycle component was optimized by the heat transfer simulation. All the optimized designs were verified by the production practice.
基金supported by the National Natural Science Foundation of China(No.21477050)the International Scientific and Technological Cooperation in Changzhou(No.CZ20140017)+2 种基金Postgraduate Research Innovation Project of Jiangsu Province(Nos.KYCX20_2561,KYCX20_2598)the Jiangsu Planned Projects for Postdoctoral Research Funds(No.2019K112)the Jiangsu Province subsidizes the recruitment of postdoctoral personnel(No.2019Z143)。
文摘Nonylphenol(NP)residues,as a typical endocrine disrupting chemical(EDC),frequently exist in sewage,surface water,groundwater and even drinking water,which poses a serious threat to human health due to its bioaccumulation.In order to remove NP,a series of MIL-100(Fe)/Zn Fe_(2)O_(4)/flake-like porous carbon nitride(MIL/ZC)was synthesized through in-situ synthesis at room temperature.High performance of ternary MIL/ZC is used to degrade NP under visible light irradiation.The results show that 30MIL/ZC2(20 wt.%Zn Fe_(2)O_(4))ternary composite had the best photocatalytic activity(99.84%)when the dosage was 30 mg.Further mechanism analysis shows that the excellent photocatalytic activity of 30MIL/ZC2could be ascribed to the double charge transfer process between flake-like porous carbon nitride(PCN)and other catalysts in the ternary heterojunction,and the separation of photogenerated electron-hole pairs was more effective.In addition,the 30MIL/ZC2 also showed high stability after five cycles of the photodegradation reaction.Furthermore,the active substance(·O_(2)^(-))was considered to be the main active substance in the NP degradation process.Based on the research results,the possible photocatalytic reaction mechanism of 30MIL/ZC2ternary composite was proposed and discussed in detail.
基金Projects supported by the National Key R&D Program of China(2020YFC1909000)Self-deployed Projects of Ganjiang Innovation Academy,Chinese Academy of Sciences(E055A001,E055A002)+1 种基金Key Research Programs of the Chinese Academy of Sciences(ZDRW-CN-2021-3)National Natural Science Foundation of China(52174113,51874148)。
文摘Improving the seepage of leaching solution in the ore body and strengthening the mass transfer process of rare earth ions during in-situ leaching are two critical methods to improve the leaching efficiency of rare earth.In this study,2 wt%MgSO_(4)solution was used for the indoor simulated column leaching experiment on rare earth samples and an electric field was applied at both ends of the samples.Then the effects of different intensities,initial application time and duration of the electric field on the rare earth leaching system and its mechanism were investigated.The results show that compared with the single MgSO_(4)solution leaching,applying an electric field with a strength of 6 V/cm can save the leaching time of 30 min and increase the flow velocity of the rare earth leachate by 26.98%.Under the optimal conditions of applying an electric field with a strength of 6 V/cm for 20 min to the leaching system after10 min of the rare earth leachate flowing out,the leaching efficiency of sample increases from 81.20% to 86.05% with the increase of 4.85%.The mechanism analysis shows that when a direct current electric field is applied to the rare earth leaching system,rare earth ions rapidly change from disorderly movement with the seepage into faster and directional movement.In addition,the seepage of the leaching solution is also improved due to the increase of the cross-sectional area of the seepage channel,the polarized water molecules migrate directionally by force from the negative pole,and the movement of the hydrogen is generated by the electrolytic water.More impo rtantly,based on the principle of in-situ leaching process,the layout of injection holes and deflector holes in this process provides a natural site for the electrode layout of the electric field.With the simple equipme nt and the ope ration,the rare earth leaching process with the applied electric field has high feasibility in industrial application.
基金jointly supported by Canadian Network for Research and Innovation in Machining TechnologyNatural Sciences and Engineering Research Council of Canada-Automotive Partnership Canada programNRCan’s Office of Energy R&D through the Program on Energy R&D
文摘The objective of this study is to predict grain size and heat transfer coefficient at the metal-die interface during high pressure die casting process and solidification of the magnesium alloy AM60. Multiple runs of the commercial casting simulation package, ProCASTTM, were used to model the mold filling and solidification events employing a range of interfacial heat transfer coefficient values. The simulation results were used to estimate the centerline cooling curve at various locations through the casting. The centerline cooling curves, together with the die temperature and the thermodynamic properties of the alloy, were then used as inputs to compute the solution to the Stefan problem of a moving phase boundary, thereby providing the through-thickness cooling curves at each chosen location of the casting, Finally, the local cooling rate was used to calculate the resulting grain size via previously established relationships. The effects of die temperature, filling time and heat transfer coefficient on the grain structure in skin region and core region were quantitatively characterized. It was observed that the grain size of skin region strongly depends on above three factors whereas the grain size of core region shows dependence on the interracial heat transfer coefficient and thickness of the samples. The grain size distribution from surface to center was estimated from the relationship between grain size and the predicted cooling rate. The prediction of grain size matches well with experimental results. A comparison of the predicted and experimentally determined grain size profiles enables the determination of the apparent interracial heat transfer coefficient for different locations.
基金supported by the Natural Science Research Youth Foundation of Hebei Higher Education of China [QN2016084]the National Natural Science Foundation of China[21878066]
文摘This paper investigates the thermal-coupled effect across the wall and the optimal heat transfer region of the wall for enhancing the energy saving effect of dividing wall column (DWC), and also studies the effects of feed thermal condition (q) and middle component composition of feed (cB) on the heat transfer process, the optimal heat transfer region, and the maximum heat transfer quantity across the wall. The simulation results show that the maximum heat transfer quantity across the wall and the potential for energy saving increase with the increase of q, while with the limitation of temperature difference across the wall, the beneficial heat transfer effect between certain range of stages, which are involved in the optimal heat transfer region, cannot be realized completely for a specific value of q. Besides, compared with q, a changing cB does not change the degree of realizing the beneficial heat transfer effect, but can bring about the variation of liquid split ratio (RL) and vapor split ratio (Rv). Thus, for achieving a maximum energy-saving effect of DWC, different q and cB need to find its own corresponding suitable heat transfer process across the wall.
文摘Fault diagnosis is an important measure to ensure the safety of production, and all kinds of fault diagnosis methods are of importance in actual production process. However, the complexity and uncertainty of production process often lead to the changes of data distribution and the emergence of new fault classes, and the number of the new fault classes is unpredictable. The reconstruction of the fault diagnosis model and the identification of new fault classes have become core issues under the circumstances. This paper presents a fault diagnosis method based on model transfer learning and the main contributions of the paper are as follows: 1) An incremental model transfer fault diagnosis method is proposed to reconstruct the new process diagnosis model. 2) Breaking the limit of existing method that the new process can only have one more class of faults than the old process, this method can identify M faults more in the new process with the thought of incremental learning. 3) The method offers a solution to a series of problems caused by the increase of fault classes. Experiments based on Tennessee-Eastman process and ore grinding classification process demonstrate the effectiveness and the feasibility of the method.
文摘In this work, the in-situ TiC panicles reinforced composite coating was prepared by plasma transferred arc process on the surface of Q235 steel. Microstructures, phase composition and wear property of the coating were investigated. The results showed that the composite coating consisted mainly of T-Ni, TiC, Cr23C6, Cr7C3, Ni3Si, CrB, Cr5B3 and FeNi3 phases, and was characterized by fine TiC panicles embedded in Ni matrix. The wear resistance of composite coating was significantly improved compared with that of the steel substrate. The wear volume loss of the substrate was 443 mm3, which was about 9 times as that of in-situ TiC particles reinforced composite coating （49 mm3 ）. It is mainly attributed to the presence of chromium carbide particles and in-situ TiC particles and their favorable combination with Ni matrix.
文摘According to heat transfer principle and the process of solving engineering problems by finite element method, examples were given to demonstrate how finite element analysis can be used to describe transient heat transfer through fabrics. Details were given to describe how conduction and convection affect temperature distribution and heat loss during heat transfer processes by taking advantage of the quick calculation of FEA software MSC.Marc. Experimental results show good agreement with the theoretical results.
基金supported by the Natural Science Foundation of China(22075043,21875034,61704093)。
文摘A pioneering glass-compatible transparent temperature alarm system self-powered by luminescent solar concentrators(LSCs) is reported.Single green-emitted organic manganese halides(OMHs) of PEA_(2)MnBr_(2)I_(2),which has a unique temperature-dependent backward energy transfer process from selftrapped state to^(4)T_(1)energy level of Mn,is used for triggering the temperature alarm.The LSC with redemitted CsPbI_(3)perovskite-polymer composite films on the glass substrate is used for power supply.The spectrally separated nature between the green-emitted OMHs for temperature alarm and red-emitted CsPbI3in LSC for power supply allows for probing the signal light of temperature-responsive OMHs without the interference of LSCs,making it possible to calibrate the temperature visually just by a self-powered brightness detection circuit with LED indicators.Taking advantage of LSC without hot spot effects plaguing the solar cells,as-prepared temperature alarm system can operate well on both sunny and cloudy day.
基金Supported by the National Key Research and Development Program of China(2018YFB0604903)National Natural Science Foundation of China(21776202,21336007)Major Science and Technology Program for Water Pollution Control and Treatment(2015ZX07202-013)
文摘The concept of process intensification(PI) has absorbed diverse definitions and stays true to the mission—'do more with less', which is an approach purposed by chemical engineers to solve the global energy & environment problems. To date, the focus of PI has been on processes mainly involving vapor/liquid systems. Based on the fundamental principles of vapor–liquid mass transfer process like distillation and absorption, there are three strategies to intensify interphase mass transfer: enhancing the overall driving force, improving the mass transfer coefficient and enlarging the vapor–liquid interfacial area. More specifically, this article herein provides an overview of various technologies to strengthen the vapor–liquid mass transfer, including application of external fields, addition of third substances, micro-chemical technology and usage of solid foam, with the objective to contribute to the future developments and potential applications of PI in scientific research and industrial sectors.
文摘Based on investigation data of PHC content in Jiaozhou Bay,China from 1979 to 1983,the seasonal variations of PHC content and monthly changes of precipitation in Jiaozhou Bay were analyzed. The results showed that seen from the spatial and temporal distribution,the seasonal variation of PHC content in the surface water of Jiaozhou Bay was based on the flow of the rivers as well as human activity,so PHC content in the rivers depended on the flow of the rivers and human activity,and the peaks and valleys of PHC content appeared in various seasons. The seasonal variation of PHC content in the surface water of Jiaozhou Bay depended on its land transfer process. The land transfer process was composed of use of PHC by mankind,deposition of PHC in soil and on the earth＇s surface,and transportation of PHC to offshore waters of sea by rivers and surface runoff. PHC content depended on mankind during the process from being used to entering soil and on precipitation during the process of being transported from soil to ocean.
文摘The energy-transfer process between sodium (omega-[2-(alpha -naphthyl)ethoxy]undecanoate (FP-)* and sodium omega -9-anthrylmethyl glutarate (AFP(-)) is accelerated by the formation of ESAg when cetyltrimethylammonium chloride (S16(+)) has been added to the solvent system of FP-* and AFP(-). This result is yet another evidence for the formation of ESAg.
基金Supported by the National Natural Science Foundation of China (No.10575131)
文摘The prompt supercritical process of a nuclear reactor with temperature feedback and initial power as well as heat transfer with a big step reactivity (ρ0>β) is analyzed in this paper. Considering the effect of heat transfer on temperature of the reactor, a new model is set up. For any initial power, the variations of output power and reactivity with time are obtained by numerical method. The effects of the big inserted step reactivity and initial power on the prompt supercritical process are analyzed and discussed. It was found that the effect of heat transfer on the output power and reactivity can be neglected under any initial power, and the output power obtained by the adiabatic model is basically in accordance with that by the model of this paper, and the analytical solution can be adopted. The results provide a theoretical base for safety analysis and operation management of a power reactor.
基金Supported by the Doctoral Degree Construction Library of Guizhou Minzu UniversitySupporting Plan Project for New Century Excellent Talents by Ministry of Education(NCET-12-0659)+5 种基金National Natural Science Foundation of China(31560107)Major Project of Science and Technology of Guizhou Province([2004]6007-01)Guizhou R&D Program for Social Development([2014]3036)Scientific Research Project for Introduction of Talents of Guizhou Minzu University([2014]02)Natural Scientific Research Project of Education Department of Guizhou Province,China(KY[2014]266)Joint Foundation of Science and Technology Department of Guizhou Province,China(LH[2014]7376)
文摘Based on the investigation data of PHC content in Jiaozhou Bay,China during 1980-1981,the vertical distribution of PHC content in the water of Jiaozhou Bay was analyzed.The results showed that from 1980 to 1981,the vertical distribution of PHC content in the water of Jiaozhou Bay depended on the water transfer process of PHC.During the water transfer process of PHC,PHC was input from pollution sources into the surface water of the bay firstly,and then it settled to the bottom.The horizontal distribution trends of PHC content in the surface and bottom water,the changes of PHC content in the surface and bottom water,and the vertical changes of PHC content showed that the settlement of PHC was fast and was consistent with PHC content.PHC accumulated at the bottom after continuous settlement of PHC,which revealed the water transfer process of PHC in Jiaozhou Bay.
基金supported by the CAS Knowledge Innovation Key Project (Grant No.KZCX2-YW-330)the National Science Fund Fostering Talents in Basic Research to Glaciology and Geocryology (Grant No.J0630966)
文摘In order to study water transfer characteristics inside non-saturated media during methane hydrate formation and dissociation processes,water changes on the top,middle and bottom locations of experimental media during the reaction processes were continuously followed with a novel apparatus with three pF-meter sensors.Coarse sand,fine sand and loess were chosen as experimental media.It was experimentally observed that methane hydrate was easier formed inside coarse sand and fine sand than inside loess.Methane hydrate formation configuration and water transfer characteristics during methane hydrate formation processes were very different among the different non-saturated media,which were important for understanding methane hydrate formation and dissociation mechanism inside sediments in nature.
基金This work was financially supported by National Defence Committee of Science and Technolgy (No. 95-YJ-20)
文摘In order to understand the relation between microstructure of superalloypowders and its solidification progress, the processing parameters are optimized during plasmarotating electrode processing (PREP). It was predicted from the results that the droplet velocities,droplet temperature, and fractional solidification with flight time about FGH95 superalloy droplethave been carried out based on Newtonian heat transfer formulation coupled with the classicalheterogeneous nucleation and the specific solidification process. It has been found that the dropletdynamic and thermal behavior is strongly affected by the distribution of droplet diameters, theproportion of cooling atmosphere, but is relatively unaffected by the droplet superheat.
文摘Knowledge transfer model of software process improvement (SPI) and the conceptual framework of influencing factors are established. The model includes five elements which are knowledge of transfer, sources of knowledge, recipients of knowledge, relationship of transfer parties, and the environment of transfer. The conceptual framework includes ten key factors which are ambiguity, systematism, transfer willingness, capacity of impartation, capacity of absorption, incen-tive mechanism, culture, technical support, trust and knowledge distance. The research hypothesis is put forward. Em-pirical study concludes that the trust relationship among SPI staffs has the greatest influence on knowledge transfer, and organizational incentive mechanism can produce positive effect to knowledge transfer of SPI. Finally, some sug-gestions are put forward to improve the knowledge transfer of SPI: establishing a rational incentive mechanism, exe-cuting some necessary training to transfer parties and using software benchmarking.
文摘Flexible transfer line(FTL)is now widely used in ma ny manufacturing domains to realize efficiently,high quantity and economic prod uction.These manufacturing domains include automobile,tractor,internal-combu stion engine,and so on.In today’s competitive business environment,it is vit ally important for machine tool manufacturers to design flexible transfer line m ore effectively and efficiently according to a wider variety of customer demand s.This paper proposes an approach to a bidding-based flexible transfer line sc hematic design system.By analyzing manual FTL design process,the architecture o f flexible transfer line schematic design system(FTLSDS)is established.The syst em consists:of four processes:part feature modeling,process planning,FTL fac i lity layout and FTL evaluation. For FTL schematic design.a five-level proces s planning strategy named hierarchical process planning method is proposed.This method includes selection of manufacturing feature machining operation;part se t-up planning,feature sequencing,operation sequencing and process plan genera ting.The major decision relies on setup planning.According to the proceeding o f the hierarchical process planning,the structure of reasoning is proposed base d on blackboard.Under this paradigm,a cooperative effort between a hybrid coll ection of knowledge sources is possible.Total reasoning task can be divided int o some subtasks,and recursive-reasoning system is formed.It is convenient for process planning with step-by-step solution.Meanwhile,the blackboard is use d as the global data exchange area during all reasoning process.By using modula r technology,special purpose machine tools can be designed more efficiently and rapidly.The framework of machine modular design system to support machine requ irement design for FTL is established.By synthesizing the FTL evaluation criter ia.five evaluation criteria of flexible transfer 1ine schematic design are take n into account.An exampie is supplied to demonstrate and verify the validity an d feasibility of flexible transfer line schematic design approach.
