Material dematerialization is a basic approach to reduce the pressure on the resources and environment and to realize the sustainable development. The material flow analysis and decomposition method are used to calcul...Material dematerialization is a basic approach to reduce the pressure on the resources and environment and to realize the sustainable development. The material flow analysis and decomposition method are used to calculate the direct material input (DMI) of 14 typical mining cities in Northeast China in 1995–2004 and to analyze the demateri- alization and its driving factors in the different types of mining cities oriented by coal, petroleum, metallurgy and multi-resources. The results are as follows: 1) from 1995 to 2006, the increase rates of the DMI and the material input intensity of mining cities declined following the order of multi-resources, metallurgy, coal, and petroleum cities, and the material utilizing efficiency did following the order of petroleum, coal, metallurgy, and multi-resources cities; 2) during the research period, all the kinds of mining cities were in the situation of weak sustainable development in most years; 3) the pressure on resources and environment in the multi-resources cities was the most serious; 4) the petro- leum cities showed the strong trend of sustainable development; and 5) in recent years, the driving function of eco- nomic development for material consuming has continuously strengthened and the controlling function of material utilizing efficiency for it has weakened. The key approaches to promote the development of circular economy of min- ing cities in Northeast China are put forward in the following aspects: 1) to strengthen the research and development of the technique of resources’ cycling utilization, 2) to improve the utilizing efficiency of resources, and 3) to carry out the auditing system of resources utilization.展开更多
Base on the framework of material flow analsis (MFA) proposed by Eurostat, this paper collected related data and conducted a regional MFA for the Chengyang Districgt in Qingdao. The indicators such as Direct Materia...Base on the framework of material flow analsis (MFA) proposed by Eurostat, this paper collected related data and conducted a regional MFA for the Chengyang Districgt in Qingdao. The indicators such as Direct Material Input(DMI), Direct Material Consumption (DMC) and Exports are calculated or estimated for the period of year 1995 through 2004. Several derivable iudicators defining direct material productivity and material intenstiy are also evaluated and some valuable conclusions were drawn. DMI in absolute number increased from about 1645.9 kilotons in 1995to about 8052.5 kilotons in 2004. Imports contribute to about 47 to 69% of DMI, and the biggest component of imports is fossil fuel that approximatley accounts far 50% of imnports. DMI per capita of Chengyang District increased rapidly and reached 17. 4 tons in 2004. Compared with other five economies studied by WRI, material consumption intensity of Chengyang District is significantly lower than developed countries, which indicates that Chengyang District is still in a development stage The direct material productivity (actual GDP per DMI) increased 59.1% from 1995 to 2004 and has been higher than either of stadies in China, which indicates efficiency of resources utilization has improved obviously in Chengyang District. But there was significant increase in material input in the last decade, which shows that rapid increase of economy is highly dependent on requirement and consumption of natural resources. Therefore, in order to promote the sustainahility, it is essential to develop circular economy and improve utilization efficiency of resources.展开更多
This article demonstrates a novel approach for material nonlinear analysis.This analysis procedure eliminates tedious and lengthy step by step incremental and then iterative procedure adopted classically and gives dir...This article demonstrates a novel approach for material nonlinear analysis.This analysis procedure eliminates tedious and lengthy step by step incremental and then iterative procedure adopted classically and gives direct results in the linear as well as in nonlinear range of the material behavior.Use of elastic moduli is eliminated.Instead,stress and strain functions are used as the material input in the analysis procedure.These stress and strain functions are directly derived from the stress-strain behavior of the material by the method of curve fitting.This way,the whole stress-strain diagram is utilized in the analysis which naturally exposes the response of structure when loading is in nonlinear range of the material behavior.It is found that it is an excellent computational procedure adopted so far for material nonlinear analysis which gives very accurate results,easy to adopt and simple in calculations.The method eliminates all types of linearity assumptions in basic derivations of equations and hence,eliminates all types of possibility of errors in the analysis procedure as well.As it is required to know stress distribution in the structural body by proper modelling and structural idealization,the proposed analysis approach can be regarded as stress-based analysis procedure.Basic problems such as uniaxial problem,beam bending,and torsion problems are solved.It is found that approach is very suitable for solving the problems of fracture mechanics.Energy release rate for plate with center crack and double cantilever beam specimen is also evaluated.The approach solves the fracture problem with relative ease in strength of material style calculations.For all problems,results are compared with the classical displacement-based liner theory.展开更多
The method "Material Flow Analysis (MFA)" is one of the effective tools to study law and quantification of material flow between economic system and ecological system. On the national level, economy-wide material ...The method "Material Flow Analysis (MFA)" is one of the effective tools to study law and quantification of material flow between economic system and ecological system. On the national level, economy-wide material flow analysis has been published for a number of countries. However, published studies on the regional or local level are still very limited and a standardized method does not exist yet. On the basis of framework of Material Flow Analysis proposed by Eurostat, the paper collected related data and analyzed material input and output for the Chengyang district in Qingdao. The results showed that DMI (Direct Material Input) and TMR (Total Material Requirement) in absolute number increased about 3.6 and 3.9 times, respectively from 1995 to 2004. Fossil fuel and mineral contributed to about 50.3%-76.3% of DMI. Imports of material increased about 5.0 times and became the most important Contributor to DMI, which showed that local economic growth was highly dependent on resources from other regions and countries. DPO (Domestic Processed Output) and TDO (Total Domestic Output) represent slow increasing trend, and DPO contributed to 22.2%-58.1% of TDO, suggesting local hidden flows were of obvious effect on TDO. The biggest component of DPO is CO2, approximately accounting for 90% of DPO. The material productivity increased 57.7% in last decade, reflecting improvement of efficiency of resources utilization in some extent. However, compared to developed countries and regions, material productivity of Chengyang district was relatively low. Therefore, in order to promote the sustainability, it is essential to develop circular economy and enhance materials productivity.展开更多
Material Flow Analysis(MFA) is a crucial instrument for sustainable development and creating industrial ecology system.MFA studies could balance and analyze the sources,flows,and consumes of specific materials or subs...Material Flow Analysis(MFA) is a crucial instrument for sustainable development and creating industrial ecology system.MFA studies could balance and analyze the sources,flows,and consumes of specific materials or substances.The results of MFA studies could support the strategies or decisions making for energy, resource,and waste management,especially achieving sustainable resource management.At CSC,the dynamic simulating software,STELLA,is used to develop a MFA model for scenario analysis.CSC also uses the freeware STAN 2.0 as a tool for visualizing and simulating material flows and stocks.Case studies of greenhouse gases MFA for integrated steel works are conducted.The results showed that the carbon content of hot-metal is an important hidden flow for balance analysis,and the different GHG emission scenarios and mitigation action scenarios are assessed.In addition,the Iron-making GHG I/O MFA Model,based on worldsteel Global Steel Sector Approach(GSSA),is developed for calculating the CO_2 and energy intensity of coke making,sintering,and BF processes.This MFA model was used to analyze the CO_2 reduction potential for iron-making process.The cases conducted for MFA applications at CSC were such as greenhouse gas,zinc,etc.In the future,CSC is going to develop a 'CSC Environment Management and Decision Supporting System' which combine MFA,LCA(life cycle assessment),and environment risk assessment.This supporting system expects to promoting energy efficiency and best resource use,supporting environment policymaking,creating environmental information value,etc.展开更多
An orthotropic functionally graded piezoelectric rectangular plate with arbitrarily distributed material properties was studied, which is simply supported and grounded(electrically) on its four lateral edges. The st...An orthotropic functionally graded piezoelectric rectangular plate with arbitrarily distributed material properties was studied, which is simply supported and grounded(electrically) on its four lateral edges. The state equations of the functionally graded piezoelectric material were obtained using the state-space approach, and a Peano-Baker series solution was obtained for the coupled electroelastic fi elds of the functionally graded piezoelectric plate subjected to mechanical and electric loading on its upper and lower surfaces. The influence of different distributions of material properties on the structural response of the plate was studied using the obtained solutions.展开更多
Precisely quantifying the strength of the proximal femur and accurately assessing hip fracture risk would enable those at high risk to be identified so that preventive interventions could be taken.Development of bette...Precisely quantifying the strength of the proximal femur and accurately assessing hip fracture risk would enable those at high risk to be identified so that preventive interventions could be taken.Development of better measures of femoral strength using the clinically展开更多
The stress distribution of notched specimen of brittle material under a plane pressure was studied using a photoelastic meth- od,When elastic deformation appeared inside the specimen,the force transferred by dowel par...The stress distribution of notched specimen of brittle material under a plane pressure was studied using a photoelastic meth- od,When elastic deformation appeared inside the specimen,the force transferred by dowel part was triangular transverse force and frictional force on the upper surface of the sample.The quantity of the frictional force was about 31 percent of transverse force.The stress inside the sample was linear along the central cross section of the sample and there was maximum tensile stress σ_y at the tip of the notch.Basing on shearing stress deviation method,the tensile stress σ_y,σ_x and shearing stress τ_(xy) at the cen- tral sections and four adjacent cross sections were calculated.The result pointed out that σ_x and τ_(xy) were smaller than σ_y.There- fore,σ_y was the main factor for crack formation and propagation.展开更多
In this paper, on the basis of the incremental Reissner variational principle.a nonlinear finite element analysis has been accomplished and a formulation of hybrid stress element has been presented for incompressible ...In this paper, on the basis of the incremental Reissner variational principle.a nonlinear finite element analysis has been accomplished and a formulation of hybrid stress element has been presented for incompressible Mooney rubber-like materials. The corrected terms of the non-equilibrium force and the incompressibility deviation are considered in the formulation. The computed values of numerical example agree very closely with the exact solution.展开更多
For a few years it has been realized that nanocrystalline phases can be formed during crystallization of amorphous alloys annealed isothermally below the crystallization temperature of usual heating experiments. Data ...For a few years it has been realized that nanocrystalline phases can be formed during crystallization of amorphous alloys annealed isothermally below the crystallization temperature of usual heating experiments. Data of this transformation monitored by the measurement of magnetic susceptibility are presented. A method using a magnetic balance with electronic stabilisation and combined computer facilities is applied. Constant heating and cooling rates as well as isothermal heat treatments are used. Magnetic measurements are able to detect the onset of the transformation of amorphous NI-P alloys much earlier than was possible with differential scanning calorimetry. The transformation kinetics can be analyzed by means of the Avrami plot based on the Johnson-Mehl-Avrami equation. The kinetics of solid state reactions in the nanostructured material can be investigated similarly. Formation of a Ni-phase in a nanostructured Hf-Ni alloy could be detected in a very early stage, where calorimetric methods are not sensitive. Segregation phenomena could be detected from the experiments even after long time. The sensitivity of the applied method is not dependent on the heating rate as the sensitivity of scanning calorimetry is.展开更多
Wood,an essential natural resource in human civilization,remains widely used despite advances in technology and material substitution.The surge in greenhouse gas emissions and environmental concerns accentuates the ne...Wood,an essential natural resource in human civilization,remains widely used despite advances in technology and material substitution.The surge in greenhouse gas emissions and environmental concerns accentuates the need for optimizing wood utilization.Material flow analysis is a powerful tool for tracking material flows and stocks,aiding resource management and environmental decision-making.However,the full extent of its methodological dimensions,particularly within the context of the wood supply chain,remains relatively unexplored.In this study,we delve into the existing literature on wood flow analysis,discussing its primary objectives,materials involved,temporal and spatial scales,data sources,units,and conversion factors.Additionally,data uncertainty,data reconciliation and crucial assumptions in material flow analysis are highlighted in this paper.Key findings reveal the significance of wood cascading and substitution effects by replacing non-wood materials,where they can reduce greenhouse gas emissions more than the natural carbon sink of forests and wood products.The immediate impact of short-term wood cascading might not be as robust as the substitution effect,with energy substitution showcasing better results than material substitution.However,it's crucial to note that these conclusions could experience significant reversal from a long-term and global perspective.Strategies for improving wood efficiency involve maximizing material use,advancing construction technologies,extending product lifespans,promoting cascade use,and optimizing energy recovery processes.The study underscores the need for standardized approaches in wood flow analysis and emphasizes the potential of wood efficiency strategies in addressing environmental challenges.展开更多
It is of great practical importance to analyze the shakedown of shell structures under cyclic loading, especially of those made of strain hardening materials.In this paper, same further understanding of the shakedown ...It is of great practical importance to analyze the shakedown of shell structures under cyclic loading, especially of those made of strain hardening materials.In this paper, same further understanding of the shakedown theorem for kinematic hardening materials has been made, and it is applied to analyze the shakedown of shell structures Though the residual stress of a real stale is related to plastic strain, the time-independent residual stress field as we will show in the theorem may be unrelated to the time-independent kinematically admissible plastic strain field For the engineering application, it will lie much more convenient to point this out clearly and definitely, otherwise it will be very difficult. Also, we have proposed a new method of proving this theorem.The above theorem is applied to the shakedown analysis of a cylindrical shell with hemispherical ends. According to the elastic solution, various possible residual sfcss and plastic strain Jlelds, the shakedown analysis of the structure can be reduced to a mathematical programming problem.The results of calculation show that the shakedown load oj strain hardening materials is about 30-40% higher than that of ideal plastic materials. So it is very important to consider the hardening of materials in the shakedown analysis,for it can greatly increase the structure design capacity, and meanwhile provide ascicntific basis to improve the design of shell structures.展开更多
Cold worked and annealed supersaturated Cu-2.65Ni-0.6Si and Cu-2.35Ni-0.6Si-0.6Cr alloys were studied. The microstructural parameters evolution, including crystallite size, root mean square strain and dislocation dens...Cold worked and annealed supersaturated Cu-2.65Ni-0.6Si and Cu-2.35Ni-0.6Si-0.6Cr alloys were studied. The microstructural parameters evolution, including crystallite size, root mean square strain and dislocation density was analyzed using Materials Analysis Using Diffraction software (MAUD). The parameters for both alloys have typical values of cold deformed and subsequently annealed copper based alloy. A net change of the crystallite size, root mean square strain and dislocation density values of the alloys aged at 450 °C for 2.5-3 h seems corresponding to the recovery and recrystallization processes. Addition of Cr as quaternary element did not lead to any drastic changes of post deformation or ageing microstructural parameters and hence of recovery-recrystallization kinetics.展开更多
The objective of this paper was to develop a comprehensive evaluation method and index to evaluate the performance of sealants and fillers for cracks in asphalt concrete pavements using the method of principal compone...The objective of this paper was to develop a comprehensive evaluation method and index to evaluate the performance of sealants and fillers for cracks in asphalt concrete pavements using the method of principal component analysis. The performance experiments including cone penetration, softening point, flow, resilience and tension at low temperature respectively were conducted by reference of ASTM D5329 for eight sealants and fillers often used in China. There by a principal component model was developed and weight of every index was calculated. The experimental results show that there are significantly different performances for sealants and fillers often used in China. Principal component analysis is an objective method that evaluates and selects the performance of sealants and fillers for cracks in asphalt concrete pavements.展开更多
Knowledge of different effects of various organic materials on soil humic substance is important for both environmental safety and sustainable agriculture.A pot experiment was conducted at Jilin Agricultural Universit...Knowledge of different effects of various organic materials on soil humic substance is important for both environmental safety and sustainable agriculture.A pot experiment was conducted at Jilin Agricultural University,Jilin Province in northeast China to discover the influence of herb residue,animal excrement,woody residue,animal remnant on fulvic acid(FA) composition and structure using differential thermal analysis-thermogravimetric(DTA-TG),fourier transform infrared spectroscopy(FTIR) and elemental analysis.DTA-TG showed the range of peak temperature in the first exothermic reaction increased following the trend: CK〉herb residue〉animal excrement〉woody residue=animal remnant,and the most weight loss was observed in animal excrement.Moreover,the second exothermic reaction of CK-and animal excrement-FA was presented as double peaks,the order of weight loss in that area was animal remnant〉CK〉woody residue〉animal excrement〉herb residue.According to FTIR,herb residue displayed higher adsorption intensity at 2 950,1 420,1 240 and 1 030 cm-1,animal excrement was in reverse.At the same time,herb residue-and animal excrement-FA had an absorption peak at 1 720 cm-1,while other organic materials didn't have this peak.As elemental analysis showed,FA isolated from various treatments was significantly distinct.It was clearly shown from our results that FA composition and structure in amended soils may be affected in different ways and at various extents on dependence of the nature and origin of amendment.展开更多
Influence of the gassing materials, such as PA6, PMMA, and POM on the dielectric properties of air are investigated. In this work, the fundamental electron collision cross section data were carefully selected and vali...Influence of the gassing materials, such as PA6, PMMA, and POM on the dielectric properties of air are investigated. In this work, the fundamental electron collision cross section data were carefully selected and validated. Then the species compositions of the air–organic vapor mixtures were calculated based on the Gibbs free energy minimization. Finally, the Townsend ionization coefficient, the Townsend electron attachment coefficient and the critical reduced electric field strength were derived from the calculated electron energy distribution function by solving the Boltzmann transport equation. The calculation results indicated that H;O with large attachment cross sections has a great impact on the critical reduced electric field strength of the air–organic vapor mixtures. On the other hand, the vaporization of gassing materials can help to increase the dielectric properties of air circuit breakers to some degree.展开更多
[Objective] Characteristics of Doppler radar data of the largest snow process since winter in Chengde City on February 26,2011 were discussed.[Method] By dint of reflection rate factors,radial velocity,and VWP product...[Objective] Characteristics of Doppler radar data of the largest snow process since winter in Chengde City on February 26,2011 were discussed.[Method] By dint of reflection rate factors,radial velocity,and VWP product of Doppler radar in C wave in Chengde of Hebei Province,and coupled with large scale of circulation situation,the largest snow process since the winter in Chengde City on February 26,2011 was discussed.[Result] The echo intensity of snow was weak.If there was certain range of 30 dBz echo and was stable,there might be strong snow.The warm advection,convection and warm and wet air climbing over the thin cold cushion in the lower layer was the main reason of the precipitation.The structure of 'cattle eye' and the torrent in the lower air provided incessant water vapor for the generation of strong precipitation.When the wind in the vertical direction changed,there was wind speed divergence,which indicated that the precipitation weakened and stopped.The existence of warm advection and shear layer was the essential reason for the maintenance of precipitation.The 'ND' area in the middle layer and the northwest wind at any height indicated the end of precipitation.[Conclusion] The study provided theoretical basis for the forecast of strong snow.展开更多
The process of economic activities is on the basis of tremendous material inputs.China has been discharging an enormous amount of waste,giving rise to a wide range of environmental impacts.The method of economy-wide m...The process of economic activities is on the basis of tremendous material inputs.China has been discharging an enormous amount of waste,giving rise to a wide range of environmental impacts.The method of economy-wide material flow analysis(EW-MFA)is one of the effective tools to examine the flow of materials entering physical economies,and recognize early environmental problems.Relevant researches are still at the early stage in China and most focus on material throughput but are rarely concerned about the utilization of recycling resource and environmental impact.Based on more than 3,000 items of data related,materials entering Chinese economy are classified into three types,and then the characteristics of material input and environmental impact are presented for the years 1990-2005 by using the indicators derived from EW-MFA.The Ratio of Recycled Material(RRM) is added as the new indicator in order to be in accordance with the need of circular economy being promoted in China.Results show that the great changes in the structure of material input cause the continuous increase of industrial solid waste emissions and the bogging down of material productivity.The RRM reveals that the utilization of recycling resources remains at a fairly low level in China.Finally,some weakness of EW-MFA is discussed according to the calculated results.展开更多
基金Under the auspices of Key Program of National Natural Science Foundation of China (No. 40635030)National Natu-ral Science Foundation of China (No. 40571041)
文摘Material dematerialization is a basic approach to reduce the pressure on the resources and environment and to realize the sustainable development. The material flow analysis and decomposition method are used to calculate the direct material input (DMI) of 14 typical mining cities in Northeast China in 1995–2004 and to analyze the demateri- alization and its driving factors in the different types of mining cities oriented by coal, petroleum, metallurgy and multi-resources. The results are as follows: 1) from 1995 to 2006, the increase rates of the DMI and the material input intensity of mining cities declined following the order of multi-resources, metallurgy, coal, and petroleum cities, and the material utilizing efficiency did following the order of petroleum, coal, metallurgy, and multi-resources cities; 2) during the research period, all the kinds of mining cities were in the situation of weak sustainable development in most years; 3) the pressure on resources and environment in the multi-resources cities was the most serious; 4) the petro- leum cities showed the strong trend of sustainable development; and 5) in recent years, the driving function of eco- nomic development for material consuming has continuously strengthened and the controlling function of material utilizing efficiency for it has weakened. The key approaches to promote the development of circular economy of min- ing cities in Northeast China are put forward in the following aspects: 1) to strengthen the research and development of the technique of resources’ cycling utilization, 2) to improve the utilizing efficiency of resources, and 3) to carry out the auditing system of resources utilization.
文摘Base on the framework of material flow analsis (MFA) proposed by Eurostat, this paper collected related data and conducted a regional MFA for the Chengyang Districgt in Qingdao. The indicators such as Direct Material Input(DMI), Direct Material Consumption (DMC) and Exports are calculated or estimated for the period of year 1995 through 2004. Several derivable iudicators defining direct material productivity and material intenstiy are also evaluated and some valuable conclusions were drawn. DMI in absolute number increased from about 1645.9 kilotons in 1995to about 8052.5 kilotons in 2004. Imports contribute to about 47 to 69% of DMI, and the biggest component of imports is fossil fuel that approximatley accounts far 50% of imnports. DMI per capita of Chengyang District increased rapidly and reached 17. 4 tons in 2004. Compared with other five economies studied by WRI, material consumption intensity of Chengyang District is significantly lower than developed countries, which indicates that Chengyang District is still in a development stage The direct material productivity (actual GDP per DMI) increased 59.1% from 1995 to 2004 and has been higher than either of stadies in China, which indicates efficiency of resources utilization has improved obviously in Chengyang District. But there was significant increase in material input in the last decade, which shows that rapid increase of economy is highly dependent on requirement and consumption of natural resources. Therefore, in order to promote the sustainahility, it is essential to develop circular economy and improve utilization efficiency of resources.
文摘This article demonstrates a novel approach for material nonlinear analysis.This analysis procedure eliminates tedious and lengthy step by step incremental and then iterative procedure adopted classically and gives direct results in the linear as well as in nonlinear range of the material behavior.Use of elastic moduli is eliminated.Instead,stress and strain functions are used as the material input in the analysis procedure.These stress and strain functions are directly derived from the stress-strain behavior of the material by the method of curve fitting.This way,the whole stress-strain diagram is utilized in the analysis which naturally exposes the response of structure when loading is in nonlinear range of the material behavior.It is found that it is an excellent computational procedure adopted so far for material nonlinear analysis which gives very accurate results,easy to adopt and simple in calculations.The method eliminates all types of linearity assumptions in basic derivations of equations and hence,eliminates all types of possibility of errors in the analysis procedure as well.As it is required to know stress distribution in the structural body by proper modelling and structural idealization,the proposed analysis approach can be regarded as stress-based analysis procedure.Basic problems such as uniaxial problem,beam bending,and torsion problems are solved.It is found that approach is very suitable for solving the problems of fracture mechanics.Energy release rate for plate with center crack and double cantilever beam specimen is also evaluated.The approach solves the fracture problem with relative ease in strength of material style calculations.For all problems,results are compared with the classical displacement-based liner theory.
基金Qingdao Agricultural University Research Fund (630707)
文摘The method "Material Flow Analysis (MFA)" is one of the effective tools to study law and quantification of material flow between economic system and ecological system. On the national level, economy-wide material flow analysis has been published for a number of countries. However, published studies on the regional or local level are still very limited and a standardized method does not exist yet. On the basis of framework of Material Flow Analysis proposed by Eurostat, the paper collected related data and analyzed material input and output for the Chengyang district in Qingdao. The results showed that DMI (Direct Material Input) and TMR (Total Material Requirement) in absolute number increased about 3.6 and 3.9 times, respectively from 1995 to 2004. Fossil fuel and mineral contributed to about 50.3%-76.3% of DMI. Imports of material increased about 5.0 times and became the most important Contributor to DMI, which showed that local economic growth was highly dependent on resources from other regions and countries. DPO (Domestic Processed Output) and TDO (Total Domestic Output) represent slow increasing trend, and DPO contributed to 22.2%-58.1% of TDO, suggesting local hidden flows were of obvious effect on TDO. The biggest component of DPO is CO2, approximately accounting for 90% of DPO. The material productivity increased 57.7% in last decade, reflecting improvement of efficiency of resources utilization in some extent. However, compared to developed countries and regions, material productivity of Chengyang district was relatively low. Therefore, in order to promote the sustainability, it is essential to develop circular economy and enhance materials productivity.
文摘Material Flow Analysis(MFA) is a crucial instrument for sustainable development and creating industrial ecology system.MFA studies could balance and analyze the sources,flows,and consumes of specific materials or substances.The results of MFA studies could support the strategies or decisions making for energy, resource,and waste management,especially achieving sustainable resource management.At CSC,the dynamic simulating software,STELLA,is used to develop a MFA model for scenario analysis.CSC also uses the freeware STAN 2.0 as a tool for visualizing and simulating material flows and stocks.Case studies of greenhouse gases MFA for integrated steel works are conducted.The results showed that the carbon content of hot-metal is an important hidden flow for balance analysis,and the different GHG emission scenarios and mitigation action scenarios are assessed.In addition,the Iron-making GHG I/O MFA Model,based on worldsteel Global Steel Sector Approach(GSSA),is developed for calculating the CO_2 and energy intensity of coke making,sintering,and BF processes.This MFA model was used to analyze the CO_2 reduction potential for iron-making process.The cases conducted for MFA applications at CSC were such as greenhouse gas,zinc,etc.In the future,CSC is going to develop a 'CSC Environment Management and Decision Supporting System' which combine MFA,LCA(life cycle assessment),and environment risk assessment.This supporting system expects to promoting energy efficiency and best resource use,supporting environment policymaking,creating environmental information value,etc.
基金Funded by the National Natural Science Foundation of China(Nos.11102136 and 41362016)the Open Project of Guangxi Key Laboratory of Disaster Prevention and Structural Safety(No.2013ZDK09)
文摘An orthotropic functionally graded piezoelectric rectangular plate with arbitrarily distributed material properties was studied, which is simply supported and grounded(electrically) on its four lateral edges. The state equations of the functionally graded piezoelectric material were obtained using the state-space approach, and a Peano-Baker series solution was obtained for the coupled electroelastic fi elds of the functionally graded piezoelectric plate subjected to mechanical and electric loading on its upper and lower surfaces. The influence of different distributions of material properties on the structural response of the plate was studied using the obtained solutions.
基金supported by The HongKong Polytechnic University Research Grants(No.1-BB81)grants from National Natural Science Foundation of China,Nos.10872078 and 10832012
文摘Precisely quantifying the strength of the proximal femur and accurately assessing hip fracture risk would enable those at high risk to be identified so that preventive interventions could be taken.Development of better measures of femoral strength using the clinically
文摘The stress distribution of notched specimen of brittle material under a plane pressure was studied using a photoelastic meth- od,When elastic deformation appeared inside the specimen,the force transferred by dowel part was triangular transverse force and frictional force on the upper surface of the sample.The quantity of the frictional force was about 31 percent of transverse force.The stress inside the sample was linear along the central cross section of the sample and there was maximum tensile stress σ_y at the tip of the notch.Basing on shearing stress deviation method,the tensile stress σ_y,σ_x and shearing stress τ_(xy) at the cen- tral sections and four adjacent cross sections were calculated.The result pointed out that σ_x and τ_(xy) were smaller than σ_y.There- fore,σ_y was the main factor for crack formation and propagation.
文摘In this paper, on the basis of the incremental Reissner variational principle.a nonlinear finite element analysis has been accomplished and a formulation of hybrid stress element has been presented for incompressible Mooney rubber-like materials. The corrected terms of the non-equilibrium force and the incompressibility deviation are considered in the formulation. The computed values of numerical example agree very closely with the exact solution.
文摘For a few years it has been realized that nanocrystalline phases can be formed during crystallization of amorphous alloys annealed isothermally below the crystallization temperature of usual heating experiments. Data of this transformation monitored by the measurement of magnetic susceptibility are presented. A method using a magnetic balance with electronic stabilisation and combined computer facilities is applied. Constant heating and cooling rates as well as isothermal heat treatments are used. Magnetic measurements are able to detect the onset of the transformation of amorphous NI-P alloys much earlier than was possible with differential scanning calorimetry. The transformation kinetics can be analyzed by means of the Avrami plot based on the Johnson-Mehl-Avrami equation. The kinetics of solid state reactions in the nanostructured material can be investigated similarly. Formation of a Ni-phase in a nanostructured Hf-Ni alloy could be detected in a very early stage, where calorimetric methods are not sensitive. Segregation phenomena could be detected from the experiments even after long time. The sensitivity of the applied method is not dependent on the heating rate as the sensitivity of scanning calorimetry is.
基金The China Scholarship Council finances this research (Grant number CSC202010220001)。
文摘Wood,an essential natural resource in human civilization,remains widely used despite advances in technology and material substitution.The surge in greenhouse gas emissions and environmental concerns accentuates the need for optimizing wood utilization.Material flow analysis is a powerful tool for tracking material flows and stocks,aiding resource management and environmental decision-making.However,the full extent of its methodological dimensions,particularly within the context of the wood supply chain,remains relatively unexplored.In this study,we delve into the existing literature on wood flow analysis,discussing its primary objectives,materials involved,temporal and spatial scales,data sources,units,and conversion factors.Additionally,data uncertainty,data reconciliation and crucial assumptions in material flow analysis are highlighted in this paper.Key findings reveal the significance of wood cascading and substitution effects by replacing non-wood materials,where they can reduce greenhouse gas emissions more than the natural carbon sink of forests and wood products.The immediate impact of short-term wood cascading might not be as robust as the substitution effect,with energy substitution showcasing better results than material substitution.However,it's crucial to note that these conclusions could experience significant reversal from a long-term and global perspective.Strategies for improving wood efficiency involve maximizing material use,advancing construction technologies,extending product lifespans,promoting cascade use,and optimizing energy recovery processes.The study underscores the need for standardized approaches in wood flow analysis and emphasizes the potential of wood efficiency strategies in addressing environmental challenges.
文摘It is of great practical importance to analyze the shakedown of shell structures under cyclic loading, especially of those made of strain hardening materials.In this paper, same further understanding of the shakedown theorem for kinematic hardening materials has been made, and it is applied to analyze the shakedown of shell structures Though the residual stress of a real stale is related to plastic strain, the time-independent residual stress field as we will show in the theorem may be unrelated to the time-independent kinematically admissible plastic strain field For the engineering application, it will lie much more convenient to point this out clearly and definitely, otherwise it will be very difficult. Also, we have proposed a new method of proving this theorem.The above theorem is applied to the shakedown analysis of a cylindrical shell with hemispherical ends. According to the elastic solution, various possible residual sfcss and plastic strain Jlelds, the shakedown analysis of the structure can be reduced to a mathematical programming problem.The results of calculation show that the shakedown load oj strain hardening materials is about 30-40% higher than that of ideal plastic materials. So it is very important to consider the hardening of materials in the shakedown analysis,for it can greatly increase the structure design capacity, and meanwhile provide ascicntific basis to improve the design of shell structures.
文摘Cold worked and annealed supersaturated Cu-2.65Ni-0.6Si and Cu-2.35Ni-0.6Si-0.6Cr alloys were studied. The microstructural parameters evolution, including crystallite size, root mean square strain and dislocation density was analyzed using Materials Analysis Using Diffraction software (MAUD). The parameters for both alloys have typical values of cold deformed and subsequently annealed copper based alloy. A net change of the crystallite size, root mean square strain and dislocation density values of the alloys aged at 450 °C for 2.5-3 h seems corresponding to the recovery and recrystallization processes. Addition of Cr as quaternary element did not lead to any drastic changes of post deformation or ageing microstructural parameters and hence of recovery-recrystallization kinetics.
基金Funded by the National Natural Science Foundation of China(Nos.51408287 and 51668038)the Rolls Supported by Program for Changjiang Scholars and Innovative Research Team in University(IRT_15R29)+2 种基金the Distinguished Young Scholars Fund of Gansu Province(1606RJDA318)the Natural Science Foundation of Gansu Province(1506RJZA064)the Excellent Program of Lanzhou Jiaotong University(201606)
文摘The objective of this paper was to develop a comprehensive evaluation method and index to evaluate the performance of sealants and fillers for cracks in asphalt concrete pavements using the method of principal component analysis. The performance experiments including cone penetration, softening point, flow, resilience and tension at low temperature respectively were conducted by reference of ASTM D5329 for eight sealants and fillers often used in China. There by a principal component model was developed and weight of every index was calculated. The experimental results show that there are significantly different performances for sealants and fillers often used in China. Principal component analysis is an objective method that evaluates and selects the performance of sealants and fillers for cracks in asphalt concrete pavements.
基金funded by the National Key Technology R&D Program of China (2012BAD14B05, 2013BAC09B01)the Major Achievement Transfer Project of Jilin Province, China (20130309005NY)
文摘Knowledge of different effects of various organic materials on soil humic substance is important for both environmental safety and sustainable agriculture.A pot experiment was conducted at Jilin Agricultural University,Jilin Province in northeast China to discover the influence of herb residue,animal excrement,woody residue,animal remnant on fulvic acid(FA) composition and structure using differential thermal analysis-thermogravimetric(DTA-TG),fourier transform infrared spectroscopy(FTIR) and elemental analysis.DTA-TG showed the range of peak temperature in the first exothermic reaction increased following the trend: CK〉herb residue〉animal excrement〉woody residue=animal remnant,and the most weight loss was observed in animal excrement.Moreover,the second exothermic reaction of CK-and animal excrement-FA was presented as double peaks,the order of weight loss in that area was animal remnant〉CK〉woody residue〉animal excrement〉herb residue.According to FTIR,herb residue displayed higher adsorption intensity at 2 950,1 420,1 240 and 1 030 cm-1,animal excrement was in reverse.At the same time,herb residue-and animal excrement-FA had an absorption peak at 1 720 cm-1,while other organic materials didn't have this peak.As elemental analysis showed,FA isolated from various treatments was significantly distinct.It was clearly shown from our results that FA composition and structure in amended soils may be affected in different ways and at various extents on dependence of the nature and origin of amendment.
基金supported by the National Key Basic Research Program of China(973 Program)2015CB251002National Natural Science Foundation of China under Grant 51521065,51577145+1 种基金the Fundamental Research Funds for the Central UniversitiesShaanxi Province Natural Science Foundation 2013JM-7010
文摘Influence of the gassing materials, such as PA6, PMMA, and POM on the dielectric properties of air are investigated. In this work, the fundamental electron collision cross section data were carefully selected and validated. Then the species compositions of the air–organic vapor mixtures were calculated based on the Gibbs free energy minimization. Finally, the Townsend ionization coefficient, the Townsend electron attachment coefficient and the critical reduced electric field strength were derived from the calculated electron energy distribution function by solving the Boltzmann transport equation. The calculation results indicated that H;O with large attachment cross sections has a great impact on the critical reduced electric field strength of the air–organic vapor mixtures. On the other hand, the vaporization of gassing materials can help to increase the dielectric properties of air circuit breakers to some degree.
基金Supported by National Science and Technology Support Program Subject (2008BAC37B01)Science and Technology Program of He-bei Meteorological Bureau (10ky03)
文摘[Objective] Characteristics of Doppler radar data of the largest snow process since winter in Chengde City on February 26,2011 were discussed.[Method] By dint of reflection rate factors,radial velocity,and VWP product of Doppler radar in C wave in Chengde of Hebei Province,and coupled with large scale of circulation situation,the largest snow process since the winter in Chengde City on February 26,2011 was discussed.[Result] The echo intensity of snow was weak.If there was certain range of 30 dBz echo and was stable,there might be strong snow.The warm advection,convection and warm and wet air climbing over the thin cold cushion in the lower layer was the main reason of the precipitation.The structure of 'cattle eye' and the torrent in the lower air provided incessant water vapor for the generation of strong precipitation.When the wind in the vertical direction changed,there was wind speed divergence,which indicated that the precipitation weakened and stopped.The existence of warm advection and shear layer was the essential reason for the maintenance of precipitation.The 'ND' area in the middle layer and the northwest wind at any height indicated the end of precipitation.[Conclusion] The study provided theoretical basis for the forecast of strong snow.
基金supported by the 10th National Five-Year Program for Science and Technology Development of China(Grant No.2003BA614A-02)
文摘The process of economic activities is on the basis of tremendous material inputs.China has been discharging an enormous amount of waste,giving rise to a wide range of environmental impacts.The method of economy-wide material flow analysis(EW-MFA)is one of the effective tools to examine the flow of materials entering physical economies,and recognize early environmental problems.Relevant researches are still at the early stage in China and most focus on material throughput but are rarely concerned about the utilization of recycling resource and environmental impact.Based on more than 3,000 items of data related,materials entering Chinese economy are classified into three types,and then the characteristics of material input and environmental impact are presented for the years 1990-2005 by using the indicators derived from EW-MFA.The Ratio of Recycled Material(RRM) is added as the new indicator in order to be in accordance with the need of circular economy being promoted in China.Results show that the great changes in the structure of material input cause the continuous increase of industrial solid waste emissions and the bogging down of material productivity.The RRM reveals that the utilization of recycling resources remains at a fairly low level in China.Finally,some weakness of EW-MFA is discussed according to the calculated results.