A new method for three-dimensional simulation of the interaction between the gas and the solid around is developed.The effects of the gas on the thermal-mechanical behaviors within the surrounded solid are performed b...A new method for three-dimensional simulation of the interaction between the gas and the solid around is developed.The effects of the gas on the thermal-mechanical behaviors within the surrounded solid are performed by replacing the internal gas with an equivalent solid in the modeling,which can make it convenient to simulate the thermal-mechanical coupling effects in the solid research objects with gases in them.The applied thermal expansion coefficient,Young's modulus and Poisson's ratio of the equivalent solid material are derived.A series of tests have been conducted;and the proposed equivalent solid method to simulate the gas effects is validated.展开更多
西安脉冲堆(Xi'an Pulsed Reactor,XAPR)超设计基准事故工况下的事故进程和现象对于深入认识XAPR的安全特性具有重要意义。为了研究XAPR大破口失水未能紧急停堆的预计瞬态(Anticipated Transient Without Scram,ATWS)事故工况下的...西安脉冲堆(Xi'an Pulsed Reactor,XAPR)超设计基准事故工况下的事故进程和现象对于深入认识XAPR的安全特性具有重要意义。为了研究XAPR大破口失水未能紧急停堆的预计瞬态(Anticipated Transient Without Scram,ATWS)事故工况下的热工水力参数和燃料棒的力学响应特性。采用一体化严重事故分析-脉冲反应堆(Integrated Severe Accident Analysis-Training Research and Isotope Production Reactor of General Atomic,ISSA-TRIGA)程序建立了XAPR模型,研究了XAPR在大破口失水ATWS事故工况下水池液位、堆芯功率、燃料和燃料棒力学行为的动态特性。结果表明:在大破口失水ATWS事故下,堆水池液位逐渐下降,事故发生64 s时,堆水池液位降低至5.55 m,堆芯自然循环能力失效,堆芯流量出现反转;事故发生230 s时,堆水池液位下降至上栅板,而296 s时堆芯全部裸露;当堆芯顶部燃料裸露后燃料温度出现上升,堆芯引入负反应性,使得堆芯功率逐渐降低,238 s时堆芯功率降低至1 MW;当堆芯液位降低至下栅板后,堆芯空气自然循环逐步建立,自然循环能够带走堆芯的热量,使得燃料温度缓慢下降。该事故中燃料最高温度为822.6 K,燃料包壳环向应力的最大值为9.72 MPa,燃料包壳应变最大值为0.35%,燃料棒未发生失效,表明XAPR在大破口失水ATWS事故工况下具有较高的固有安全性。展开更多
Carbon dissolution from solid fuels used in a COREX gasifier was investigated in a high-temperature furnace to investigate the influences of temperature, carbon structure and ash properties of solid fuels into molten ...Carbon dissolution from solid fuels used in a COREX gasifier was investigated in a high-temperature furnace to investigate the influences of temperature, carbon structure and ash properties of solid fuels into molten iron on carbon dissolution behavior. The results showed that the final carbon content of molten iron and dissolution reaction rate of carbon increased as the temperature increased. However, the dissolution behavior of different solid fuels varied with their properties. At the same temperature, the dissolution reaction rate of solid fuel from high to low was coke, semi-coke and lump coal. The apparent reaction rate constants of solid fuel were calculated using the piecewise fitting method based on the experimental data. The analyzed results showed that the dissolution rates of solid fuels had a good correlation with their microcrystalline structures. Moreover, the carbon crystallite structures of solid fuels used in COREX had greater influence on dissolution behavior than their ash properties.展开更多
Based on the grea field investigation and experiment in laboratory, four fuel types wer classified for all broad-leaved/Korean pine forests and its plantations in northeast China in this paper. Various kinds of fuel l...Based on the grea field investigation and experiment in laboratory, four fuel types wer classified for all broad-leaved/Korean pine forests and its plantations in northeast China in this paper. Various kinds of fuel loads, combuStibility and potential energy are calculated and discussed.The relationships between fuel types, fire environment and fire behavior are also widely expounds,and some researh results and management suggestion on Konan pine forests are also given in the paper.展开更多
This paper summarizes the fuel type systems currently adopted by the fire danger rating systems or fire behavior prediction systems of some countries, such as Canada, the United States, Australia, Greece, and Switzerl...This paper summarizes the fuel type systems currently adopted by the fire danger rating systems or fire behavior prediction systems of some countries, such as Canada, the United States, Australia, Greece, and Switzerland. As an example, the Canadian Forest Fire Danger Rating System organizes fuel types into five major groups, with a total of 16 discrete fuel types recognized. In the United States National Fire Danger Rating System, fuel models are divided into four vegetation groups and twenty fire behavior fuel models. The Promethus System （Greece） divides fuels into 7 types, and Australia has adopted only three distinct fuel types： open grasslands, dry eucalyptus forests, and heath/shrublands. Four approaches to mapping fuels are acceptable： field reconnaissance, direct mapping methods, indirect mapping methods, and gradient modeling. Satellite remote-sensing techniques provide an alternative source of obtaining fuel data quickly, since they provide comprehensive spatial coverage and enough temporal resolution to update fuel maps in a more efficient and timely manner than traditional aerial photography or fieldwork. Satellite sensors can also provide digital information that can be easily tied into other spatial databases using Geographic Information System （GIS） analysis, which can be used as input in fire behavior and growth models. Various fuel-mapping methods from satellite remote sensing are discussed in the paper. According to the analysis of the fuel mapping techniques worldwide, this paper suggests that China should first create appropriate fuel types for its fire agencies before embarking on developing a national fire danger rating system to improve the current data situation for it＇s fire management programs.展开更多
Despite the current threat from climate change,plastic collecting in the world's oceans,and the steady loss of biodiversity,the world continually fails to take action with regard to our rapidly changing ecosystem....Despite the current threat from climate change,plastic collecting in the world's oceans,and the steady loss of biodiversity,the world continually fails to take action with regard to our rapidly changing ecosystem.Unfortunately,waiting on governments to act is no longer a viable option.Rapid change is needed and the pace of diplomacy is simply too slow.Democratic governments are reactionary and taking action to solve future problems is not a priority,even as the threat of potential ecological catastrophe draws ever closer.Change is in the hands of individuals,and it is our decisions and behaviors that will influence the future of our planet and our ability to inhabit it.Therefore,building momentum for sustainable behavior must begin with individuals.The neoliberal approach to environmental protection posits that individuals are motivated by rational self-interest,and that economic incentives are necessary to achieve environmental goals.However,recent research suggests that monetary gain alone actually negatively impacts behavior,and often neglects the rural poor.As a result,models for projects designed to benefit the environment need more than just a monetary incentive,they must incorporate all three pillars of sustainability:environment,economy and society.One approach for building momentum for sustainable behavior with regard to municipal solid waste management,particularly in the developing world,is by implementing Locally Managed Decentralized Circular Economy(LMDCE)principles.This contribution will describe the role behavioral economics plays in the choices made by producers and consumers.The results of a case study on applying LMDCE principles in Uganda to manage waste plastic accumulation by conversion to fuel oil will be presented.展开更多
基金Supported by Natural Science Foundation of China(Nos.10772049 and 11072062)Research and Development Program of China(863 Program, No.2009AA04Z408)+1 种基金Natural Science Foundation of Shanghai(No.06ZR14009)Pujiang Scholar Program and the Wangdao Scholar Program(No.08076) of Fudan University
文摘A new method for three-dimensional simulation of the interaction between the gas and the solid around is developed.The effects of the gas on the thermal-mechanical behaviors within the surrounded solid are performed by replacing the internal gas with an equivalent solid in the modeling,which can make it convenient to simulate the thermal-mechanical coupling effects in the solid research objects with gases in them.The applied thermal expansion coefficient,Young's modulus and Poisson's ratio of the equivalent solid material are derived.A series of tests have been conducted;and the proposed equivalent solid method to simulate the gas effects is validated.
文摘西安脉冲堆(Xi'an Pulsed Reactor,XAPR)超设计基准事故工况下的事故进程和现象对于深入认识XAPR的安全特性具有重要意义。为了研究XAPR大破口失水未能紧急停堆的预计瞬态(Anticipated Transient Without Scram,ATWS)事故工况下的热工水力参数和燃料棒的力学响应特性。采用一体化严重事故分析-脉冲反应堆(Integrated Severe Accident Analysis-Training Research and Isotope Production Reactor of General Atomic,ISSA-TRIGA)程序建立了XAPR模型,研究了XAPR在大破口失水ATWS事故工况下水池液位、堆芯功率、燃料和燃料棒力学行为的动态特性。结果表明:在大破口失水ATWS事故下,堆水池液位逐渐下降,事故发生64 s时,堆水池液位降低至5.55 m,堆芯自然循环能力失效,堆芯流量出现反转;事故发生230 s时,堆水池液位下降至上栅板,而296 s时堆芯全部裸露;当堆芯顶部燃料裸露后燃料温度出现上升,堆芯引入负反应性,使得堆芯功率逐渐降低,238 s时堆芯功率降低至1 MW;当堆芯液位降低至下栅板后,堆芯空气自然循环逐步建立,自然循环能够带走堆芯的热量,使得燃料温度缓慢下降。该事故中燃料最高温度为822.6 K,燃料包壳环向应力的最大值为9.72 MPa,燃料包壳应变最大值为0.35%,燃料棒未发生失效,表明XAPR在大破口失水ATWS事故工况下具有较高的固有安全性。
基金The authors acknowledge the financial support from the National Natural Science Foundation of China （Nos. 51704216, 51474164 and U201760101） and China Postdoctoral Science Foundation （No. 2016M602378）.
文摘Carbon dissolution from solid fuels used in a COREX gasifier was investigated in a high-temperature furnace to investigate the influences of temperature, carbon structure and ash properties of solid fuels into molten iron on carbon dissolution behavior. The results showed that the final carbon content of molten iron and dissolution reaction rate of carbon increased as the temperature increased. However, the dissolution behavior of different solid fuels varied with their properties. At the same temperature, the dissolution reaction rate of solid fuel from high to low was coke, semi-coke and lump coal. The apparent reaction rate constants of solid fuel were calculated using the piecewise fitting method based on the experimental data. The analyzed results showed that the dissolution rates of solid fuels had a good correlation with their microcrystalline structures. Moreover, the carbon crystallite structures of solid fuels used in COREX had greater influence on dissolution behavior than their ash properties.
文摘Based on the grea field investigation and experiment in laboratory, four fuel types wer classified for all broad-leaved/Korean pine forests and its plantations in northeast China in this paper. Various kinds of fuel loads, combuStibility and potential energy are calculated and discussed.The relationships between fuel types, fire environment and fire behavior are also widely expounds,and some researh results and management suggestion on Konan pine forests are also given in the paper.
基金This paper was supported by the Beijing Fund of Nature Science (No. 6042025), China NKBRSF Project (No. 2001CB409600) and Laboratory of Forest Protection, State Forestry Administration
文摘This paper summarizes the fuel type systems currently adopted by the fire danger rating systems or fire behavior prediction systems of some countries, such as Canada, the United States, Australia, Greece, and Switzerland. As an example, the Canadian Forest Fire Danger Rating System organizes fuel types into five major groups, with a total of 16 discrete fuel types recognized. In the United States National Fire Danger Rating System, fuel models are divided into four vegetation groups and twenty fire behavior fuel models. The Promethus System （Greece） divides fuels into 7 types, and Australia has adopted only three distinct fuel types： open grasslands, dry eucalyptus forests, and heath/shrublands. Four approaches to mapping fuels are acceptable： field reconnaissance, direct mapping methods, indirect mapping methods, and gradient modeling. Satellite remote-sensing techniques provide an alternative source of obtaining fuel data quickly, since they provide comprehensive spatial coverage and enough temporal resolution to update fuel maps in a more efficient and timely manner than traditional aerial photography or fieldwork. Satellite sensors can also provide digital information that can be easily tied into other spatial databases using Geographic Information System （GIS） analysis, which can be used as input in fire behavior and growth models. Various fuel-mapping methods from satellite remote sensing are discussed in the paper. According to the analysis of the fuel mapping techniques worldwide, this paper suggests that China should first create appropriate fuel types for its fire agencies before embarking on developing a national fire danger rating system to improve the current data situation for it＇s fire management programs.
基金Funding for the Kampala case study was provided by the Rotary Club of Paducah, Kentucky
文摘Despite the current threat from climate change,plastic collecting in the world's oceans,and the steady loss of biodiversity,the world continually fails to take action with regard to our rapidly changing ecosystem.Unfortunately,waiting on governments to act is no longer a viable option.Rapid change is needed and the pace of diplomacy is simply too slow.Democratic governments are reactionary and taking action to solve future problems is not a priority,even as the threat of potential ecological catastrophe draws ever closer.Change is in the hands of individuals,and it is our decisions and behaviors that will influence the future of our planet and our ability to inhabit it.Therefore,building momentum for sustainable behavior must begin with individuals.The neoliberal approach to environmental protection posits that individuals are motivated by rational self-interest,and that economic incentives are necessary to achieve environmental goals.However,recent research suggests that monetary gain alone actually negatively impacts behavior,and often neglects the rural poor.As a result,models for projects designed to benefit the environment need more than just a monetary incentive,they must incorporate all three pillars of sustainability:environment,economy and society.One approach for building momentum for sustainable behavior with regard to municipal solid waste management,particularly in the developing world,is by implementing Locally Managed Decentralized Circular Economy(LMDCE)principles.This contribution will describe the role behavioral economics plays in the choices made by producers and consumers.The results of a case study on applying LMDCE principles in Uganda to manage waste plastic accumulation by conversion to fuel oil will be presented.
