[Objective] The aim was to calculate the safe straw volume using Frank- Kamenetskii Model to provide method for fire protection in forage farm. [Method] Frank-Kamenetskii Model was used to measure Tacr and improved by...[Objective] The aim was to calculate the safe straw volume using Frank- Kamenetskii Model to provide method for fire protection in forage farm. [Method] Frank-Kamenetskii Model was used to measure Tacr and improved by marginal tem- perature which was adjustable. In addition, effects of water content and density of baled straws on Tc were explored using the improved model. [Result] Size of straw bales was the key factor determining whether spontaneous combustion would occur. For baled straws with water at 15.27% and density at 285 kg/m3, Tc was 85-88 ~C and safe diameter of baled straws maximized 8.2 m. In addition, straws should be stacked from south to north （or north to south） to avoid sunshine and certain space should be kept between straw bales for heat dissipation. [Conclusion] The research is of significance for safe management of forage farm.展开更多
An incrementally nonlinear hypoplastic constitutive model was introduced, which was developed without recourse to the concepts in elastoplasticity theory such as yield surface, plastic potential and the decomposition ...An incrementally nonlinear hypoplastic constitutive model was introduced, which was developed without recourse to the concepts in elastoplasticity theory such as yield surface, plastic potential and the decomposition of the deformation into elastic and plastic parts. Triaxial drained tests on rockfill were conducted on a large scale triaxial apparatus under two types of stress paths, which were the stress paths of constant stress ratio and the complex stress paths with transitional features. Motivated by the effect of stress path, the Gudehus-Bauer hypoplastic model was improved by considering the parameter variations with different ratios of stress increment. Fitting parameter a presents a piecewise linear relationship with cosine of the slope angle θ determined by instantaneous stress path. The improved hypoplastic model can present peak stress increasing and volumetric strain changing from dilatancy to contractancy with the increase of transitional confining pressure σ3t and the decrease of slope angle θ of stress path. Compared with the test data, it is shown that the model is capable of fully considering the effect of stress path on rockfill.展开更多
The concrete-faced rockfill dam(CFRD) is an important dam type in the selection of high dams to be constructed in Western China,owing to its direct utilization of local materials,good adaptability,and distinct economi...The concrete-faced rockfill dam(CFRD) is an important dam type in the selection of high dams to be constructed in Western China,owing to its direct utilization of local materials,good adaptability,and distinct economic advantages.Over the past decades,China has gained successful experience in the construction of 200 m CFRDs,providing the necessary technical accumulation for the development of 250–300 m ultra-high CFRDs.This paper summarizes these successful experiences and analyzes the problems of a number of major 200 m CFRDs around the world.In addition,it discusses the key technologies and latest research progress regarding safety in the construction of 250–300 m ultra-high CFRDs,and suggests focuses and general ideas for future research.展开更多
In 2011,the Chinese Academy of Sciences launched an engineering project to develop an acceleratordriven subcritical system(ADS)for nuclear waste transmutation.The China Lead-based Reactor(CLEAR),proposed by the Instit...In 2011,the Chinese Academy of Sciences launched an engineering project to develop an acceleratordriven subcritical system(ADS)for nuclear waste transmutation.The China Lead-based Reactor(CLEAR),proposed by the Institute of Nuclear Energy Safety Technology,was selected as the reference reactor for ADS development,as well as for the technology development of the Generation IV lead-cooled fast reactor.The conceptual design of CLEAR-I with 10 MW thermal power has been completed.KYLIN series lead-bismuth eutectic experimental loops have been constructed to investigate the technologies of the coolant,key components,structural materials,fuel assembly,operation,and control.In order to validate and test the key components and integrated operating technology of the lead-based reactor,the lead alloy-cooled non-nuclear reactor CLEAR-S,the lead-based zero-power nuclear reactor CLEAR-0,and the lead-based virtual reactor CLEAR-V are under realization.展开更多
Reaction runaway has longtime been an issue in chemical industry as it often leads to severe accidents if not controlled and inhibited properly.Herein we have reviewed several key considerations and procedures to prev...Reaction runaway has longtime been an issue in chemical industry as it often leads to severe accidents if not controlled and inhibited properly.Herein we have reviewed several key considerations and procedures to prevent such phenomena,including inherently safer reactor design,thermal risk assessment and early warning detection of runaway,and pointed out that the basic principle underlying is necessary heat management and construction of resilient processes.For inherently safer reactor design,important factors such as heat removal,heat capacitance,flow behaviors and explosive behaviors have been investigated.The survey shows that heat exchanger(HEX) reactor and microreactor outperform traditional reactors.Meanwhile,we have looked into the effect of thermal risk ranking and safety operation region determining for thermal risk assessment,and the influence of runaway criteria and construction methods for early detection of reaction runaway as well.It shows that thermal risk assessment plays a key role on process design,and early warning detection system(EWDS) is preferable on prevention of reaction runaway.In the end,perspectives regarding inherently safer designs with the measures discussed above have been provided.展开更多
Aiming at the problem of small area human occlusion in gait recognition,a method based on generating adversarial image inpainting network was proposed which can generate a context consistent image for gait occlusion a...Aiming at the problem of small area human occlusion in gait recognition,a method based on generating adversarial image inpainting network was proposed which can generate a context consistent image for gait occlusion area.In order to reduce the effect of noise on feature extraction,the stacked automatic encoder with robustness was used.In order to improve the ability of gait classification,the sparse coding was used to express and classify the gait features.Experiments results showed the effectiveness of the proposed method in comparison with other state-of-the-art methods on the public databases CASIA-B and TUM-GAID for gait recognition.展开更多
The seismic safety of nuclear power plan(tNPP)has always been a major consideration in the site selection,design,operation,and more recently recertification of existing installations. In addition to the actual NPP and...The seismic safety of nuclear power plan(tNPP)has always been a major consideration in the site selection,design,operation,and more recently recertification of existing installations. In addition to the actual NPP and all their operational and safety related support systems,the storage of spent fuel in temporary or permanent storage facilities also poses a seismic risk. This seismic risk is typically assessed with state-of-the-art modeling and analytical tools that capture everything from the ground rupture or source of the earthquake to the site specific ground shaking,taking geotechnical parameters and soilfoundationstructureinteraction (SFSI) into account to the non-linear structural response of the reactor core,the containment structure,the core cooling system and the emergency cooling system(s),to support systems,piping systems and non-structural components,and finally the performance of spent fuel storage in the probabilistically determined operational basis earthquake (OBE) or the safe shutdown earthquake (SSE) scenario. The best and most meaningful validation and verification of these advanced analytical tools is in the form of full or very large scale experimental testing,designed and conducted in direct support of model and analysis tool calibration. This paper outlines the principles under which such calibration testing should be conducted and illustrates with examples the kind of testing and parameter evaluation required.展开更多
HPR1000 is an advanced nuclear power plant(NPP)with the significant feature of an active and passive safety design philosophy,developed by the China National Nuclear Corporation.On one hand,it is an evolutionary desig...HPR1000 is an advanced nuclear power plant(NPP)with the significant feature of an active and passive safety design philosophy,developed by the China National Nuclear Corporation.On one hand,it is an evolutionary design based on proven technology of the existing pressurized water reactor NPP;on the other hand,it incorporates advanced design features including a 177-fuel-assembly core loaded with CF3 fuel assemblies,active and passive safety systems,comprehensive severe accident prevention and mitigation measures,enhanced protection against external events,and improved emergency response capability.Extensive verification experiments and tests have been performed for critical innovative improvements on passive systems,the reactor core,and the main equipment.The design of HPR1000fulfills the international utility requirements for advanced light water reactors and the latest nuclear safety requirements,and addresses the safety issues relevant to the Fukushima accident.Along with its outstanding safety and economy,HPR1000 provides an excellent and practicable solution for both domestic and international nuclear power markets.展开更多
This work presents results on the commissioning of the new heat exchanger of the IEA-R1 nuclear reactor in the occasion of its operational power upgrade from 2 MW to 5 MW, in comparison to the values calculated in the...This work presents results on the commissioning of the new heat exchanger of the IEA-R1 nuclear reactor in the occasion of its operational power upgrade from 2 MW to 5 MW, in comparison to the values calculated in the project of IESA Design and Equipments Company. This reactor is a swimming pool type, light water moderated and with graphite reflectors, used for research purposes and medical radioisotopes production. During monitoring procedures, issues were observed on the reactor operation at 5 MW mainly due to the ageing of the reactor＇s oldest heat exchanger （TC-A） and excessive vibrations at high flow rates on the other installed heat exchanger （TC-B）. So it was decided to provide a new IESA heat exchanger with 5 MW capacity to definitely substitute the TC-A heat exchanger. The results show that the IEA-R1 nuclear reactor can be operated safely and continuously at 5 MW with the new IESA heat exchanger.展开更多
基金Supported by Fund for Philosophy&Social Sciences of Jiangsu Provincial Department of Education(2011SJD820013)A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)Scientific Research Fund of Jiangsu Police Institute(11Y03)~~
文摘[Objective] The aim was to calculate the safe straw volume using Frank- Kamenetskii Model to provide method for fire protection in forage farm. [Method] Frank-Kamenetskii Model was used to measure Tacr and improved by marginal tem- perature which was adjustable. In addition, effects of water content and density of baled straws on Tc were explored using the improved model. [Result] Size of straw bales was the key factor determining whether spontaneous combustion would occur. For baled straws with water at 15.27% and density at 285 kg/m3, Tc was 85-88 ~C and safe diameter of baled straws maximized 8.2 m. In addition, straws should be stacked from south to north （or north to south） to avoid sunshine and certain space should be kept between straw bales for heat dissipation. [Conclusion] The research is of significance for safe management of forage farm.
基金Projects(50479057, 50639060) supported by the National Natural Science Foundation of China
文摘An incrementally nonlinear hypoplastic constitutive model was introduced, which was developed without recourse to the concepts in elastoplasticity theory such as yield surface, plastic potential and the decomposition of the deformation into elastic and plastic parts. Triaxial drained tests on rockfill were conducted on a large scale triaxial apparatus under two types of stress paths, which were the stress paths of constant stress ratio and the complex stress paths with transitional features. Motivated by the effect of stress path, the Gudehus-Bauer hypoplastic model was improved by considering the parameter variations with different ratios of stress increment. Fitting parameter a presents a piecewise linear relationship with cosine of the slope angle θ determined by instantaneous stress path. The improved hypoplastic model can present peak stress increasing and volumetric strain changing from dilatancy to contractancy with the increase of transitional confining pressure σ3t and the decrease of slope angle θ of stress path. Compared with the test data, it is shown that the model is capable of fully considering the effect of stress path on rockfill.
文摘The concrete-faced rockfill dam(CFRD) is an important dam type in the selection of high dams to be constructed in Western China,owing to its direct utilization of local materials,good adaptability,and distinct economic advantages.Over the past decades,China has gained successful experience in the construction of 200 m CFRDs,providing the necessary technical accumulation for the development of 250–300 m ultra-high CFRDs.This paper summarizes these successful experiences and analyzes the problems of a number of major 200 m CFRDs around the world.In addition,it discusses the key technologies and latest research progress regarding safety in the construction of 250–300 m ultra-high CFRDs,and suggests focuses and general ideas for future research.
文摘In 2011,the Chinese Academy of Sciences launched an engineering project to develop an acceleratordriven subcritical system(ADS)for nuclear waste transmutation.The China Lead-based Reactor(CLEAR),proposed by the Institute of Nuclear Energy Safety Technology,was selected as the reference reactor for ADS development,as well as for the technology development of the Generation IV lead-cooled fast reactor.The conceptual design of CLEAR-I with 10 MW thermal power has been completed.KYLIN series lead-bismuth eutectic experimental loops have been constructed to investigate the technologies of the coolant,key components,structural materials,fuel assembly,operation,and control.In order to validate and test the key components and integrated operating technology of the lead-based reactor,the lead alloy-cooled non-nuclear reactor CLEAR-S,the lead-based zero-power nuclear reactor CLEAR-0,and the lead-based virtual reactor CLEAR-V are under realization.
基金Supported by the National Key Research and Development Program of China(2016YFB0301701)
文摘Reaction runaway has longtime been an issue in chemical industry as it often leads to severe accidents if not controlled and inhibited properly.Herein we have reviewed several key considerations and procedures to prevent such phenomena,including inherently safer reactor design,thermal risk assessment and early warning detection of runaway,and pointed out that the basic principle underlying is necessary heat management and construction of resilient processes.For inherently safer reactor design,important factors such as heat removal,heat capacitance,flow behaviors and explosive behaviors have been investigated.The survey shows that heat exchanger(HEX) reactor and microreactor outperform traditional reactors.Meanwhile,we have looked into the effect of thermal risk ranking and safety operation region determining for thermal risk assessment,and the influence of runaway criteria and construction methods for early detection of reaction runaway as well.It shows that thermal risk assessment plays a key role on process design,and early warning detection system(EWDS) is preferable on prevention of reaction runaway.In the end,perspectives regarding inherently safer designs with the measures discussed above have been provided.
基金Project(51678075) supported by the National Natural Science Foundation of ChinaProject(2017GK2271) supported by Hunan Provincial Science and Technology Department,China
文摘Aiming at the problem of small area human occlusion in gait recognition,a method based on generating adversarial image inpainting network was proposed which can generate a context consistent image for gait occlusion area.In order to reduce the effect of noise on feature extraction,the stacked automatic encoder with robustness was used.In order to improve the ability of gait classification,the sparse coding was used to express and classify the gait features.Experiments results showed the effectiveness of the proposed method in comparison with other state-of-the-art methods on the public databases CASIA-B and TUM-GAID for gait recognition.
文摘The seismic safety of nuclear power plan(tNPP)has always been a major consideration in the site selection,design,operation,and more recently recertification of existing installations. In addition to the actual NPP and all their operational and safety related support systems,the storage of spent fuel in temporary or permanent storage facilities also poses a seismic risk. This seismic risk is typically assessed with state-of-the-art modeling and analytical tools that capture everything from the ground rupture or source of the earthquake to the site specific ground shaking,taking geotechnical parameters and soilfoundationstructureinteraction (SFSI) into account to the non-linear structural response of the reactor core,the containment structure,the core cooling system and the emergency cooling system(s),to support systems,piping systems and non-structural components,and finally the performance of spent fuel storage in the probabilistically determined operational basis earthquake (OBE) or the safe shutdown earthquake (SSE) scenario. The best and most meaningful validation and verification of these advanced analytical tools is in the form of full or very large scale experimental testing,designed and conducted in direct support of model and analysis tool calibration. This paper outlines the principles under which such calibration testing should be conducted and illustrates with examples the kind of testing and parameter evaluation required.
文摘HPR1000 is an advanced nuclear power plant(NPP)with the significant feature of an active and passive safety design philosophy,developed by the China National Nuclear Corporation.On one hand,it is an evolutionary design based on proven technology of the existing pressurized water reactor NPP;on the other hand,it incorporates advanced design features including a 177-fuel-assembly core loaded with CF3 fuel assemblies,active and passive safety systems,comprehensive severe accident prevention and mitigation measures,enhanced protection against external events,and improved emergency response capability.Extensive verification experiments and tests have been performed for critical innovative improvements on passive systems,the reactor core,and the main equipment.The design of HPR1000fulfills the international utility requirements for advanced light water reactors and the latest nuclear safety requirements,and addresses the safety issues relevant to the Fukushima accident.Along with its outstanding safety and economy,HPR1000 provides an excellent and practicable solution for both domestic and international nuclear power markets.
文摘This work presents results on the commissioning of the new heat exchanger of the IEA-R1 nuclear reactor in the occasion of its operational power upgrade from 2 MW to 5 MW, in comparison to the values calculated in the project of IESA Design and Equipments Company. This reactor is a swimming pool type, light water moderated and with graphite reflectors, used for research purposes and medical radioisotopes production. During monitoring procedures, issues were observed on the reactor operation at 5 MW mainly due to the ageing of the reactor＇s oldest heat exchanger （TC-A） and excessive vibrations at high flow rates on the other installed heat exchanger （TC-B）. So it was decided to provide a new IESA heat exchanger with 5 MW capacity to definitely substitute the TC-A heat exchanger. The results show that the IEA-R1 nuclear reactor can be operated safely and continuously at 5 MW with the new IESA heat exchanger.
