The paper is undertaken with the objective of describing a new method for treating ductile cast iron in a ladle process, where the main objective is to minimize formation of eutectic carbides and shrinkage porosity du...The paper is undertaken with the objective of describing a new method for treating ductile cast iron in a ladle process, where the main objective is to minimize formation of eutectic carbides and shrinkage porosity during solidification. The suppression of carbide formation is associated with the nucleating properties of the nodularizer and inoculant alloys. By nucleating properties it is understood the number and potency of nuclei formed by an alloy addition. The nodularizer and inoculant additions also influence ductile iron solidification shrinkage. Some alloys may give good protection against shrinkage while others tend to promote more shrinkage. The use of various rare earth elements is found to have a pronounced impact on these conditions. It has been discovered that the use of pure lanthanum as the primary rare earth source in the magnesium ferrosilicon nodularizer surprisingly further improves the performance of the ductile iron ladle treatment method compared to similar methods using cerium or mishmetal bearing nodularizers. The nucleating properties are substantially improved and the risk for carbides (chill) and shrinkage formation in the sandwich or tundish ladle treated ductile iron is then minimized. The paper describes this new ladle treatment concept in detail, and gives examples from successful testing of the new nodularizing technology and how it simultaneously affects and minimizes critical ductile iron chill and shrinkage tendencies.展开更多
The optimization investment policy decision of SCM-Supply Chain Management-implementation has been analysed under symmetric and asymmetric information conditions. For both conditions, SCM implementation options’ deci...The optimization investment policy decision of SCM-Supply Chain Management-implementation has been analysed under symmetric and asymmetric information conditions. For both conditions, SCM implementation options’ decision optimizing models have been developed. In these models, both clients and vendors try to pursue their own benefits. Based upon the principal-agent theory, the models show to what extent a principal (a client) needs to pay more to an agent (a vendor) in a context of asymmetric information. For the client, it is important to understand the extra costs to be able to adopt effective strategies to stimulate a vendor to perform an optimal implementation of a SCM system. The results of a simulation experiment regarding SCM implementation options illustrate and verify the theoretical findings and confirm the general notion that the less informed party is obliged to pay information rent to the better-informed party.展开更多
The hybrid power-and voltage-based synchronization control method has shown potential for enhancing the stability of grid-forming(GFM)inverters.However,its effectiveness may be compromised if other control loops are n...The hybrid power-and voltage-based synchronization control method has shown potential for enhancing the stability of grid-forming(GFM)inverters.However,its effectiveness may be compromised if other control loops are not properly designed.To address the control-loop interactions,this paper presents a design-oriented analysis method for multiloop-controlled GFM inverters.The method begins by identifying the dominant oscillation modes through modal analysis.The sensitivities of damping ratios to control parameters are then determined for the dominant modes,which allows for characterization of control-loop interactions.A co-design method of GFM control is next developed based on the sensitivity analysis.Lastly,simulations and experimental results are presented to confirm the effectiveness of the method.展开更多
A T-shape tube hydraulic bulge test under axial feeding force is carried out to characterize the mechanical properties of EN AW 5049-O and 6060-O aluminium alloys.The punch displacement,T-branch height and axial compr...A T-shape tube hydraulic bulge test under axial feeding force is carried out to characterize the mechanical properties of EN AW 5049-O and 6060-O aluminium alloys.The punch displacement,T-branch height and axial compressive force are recorded online during the experiment.An intelligent inverse identification framework combining the finite element method and numerical optimization algorithm is developed to determine material parameters by fitting simulated results to the experimental data iteratively.The identified constitutive parameters using the inverse modelling technique are compared with those determined by the theoretical analysis and uniaxial tensile test.The comparison shows that the predicted bulge height and punch force based on the material parameters obtained by the three methods are different and the inverse strategy produces the smallest gap between numerical and experimental values.It is possible to conclude that the hydraulic bulge test can be applied to characterize the stress-strain curve of tubular materials at the large strain scope,and the automatic inverse framework is a more accurate post-processing procedure to identify material constitutive parameters compared with the classical analytical model.展开更多
Pollution cost control is key to solve pollution problem.The paper takes pollution control cost of pollution control contract between management authority and pollutant discharge enterprise as research object,consider...Pollution cost control is key to solve pollution problem.The paper takes pollution control cost of pollution control contract between management authority and pollutant discharge enterprise as research object,considers pollution control quality level,pollution control quality inspection and pollution control cost model,and establishes pollution control cost model of management authority and pollutant discharge enterprise,including rational constraints of pollutant discharge enterprise.And it analyzes principal-agent relationship between the two under condition of asymmetric information,and un-observability of pollution control level is shown as hiding information of sewage enterprises.In essence,it is problem of adverse selection in principal-agent.Pollution control cost of management is objective function.The first order condition of pollution control cost of sewage enterprise is transformed into state space equation,and optimal control of problem is solved by using maximum principle.In particular,management authority,as principal,uses pollution control provisions to reward,punish and encourage pollutant discharge enterprises as agents.展开更多
The optimization investment policy decision of SCM-supply chain management-implementation has been analysed under symmetric and asymmetric information conditions.For both conditions,SCM implementation optional decisio...The optimization investment policy decision of SCM-supply chain management-implementation has been analysed under symmetric and asymmetric information conditions.For both conditions,SCM implementation optional decision optimizing models have been developed.In these models,both clients and vendors try to pursue their own benefits.Based upon the principal-agent theory,the models show to what extent a principal(a client)needs to pay more to an agent(a vendor)in a context of asymmetric information.For the client it is important to understand the extra costs to be able to adopt effective strategies to stimulate a vendor to perform an optimal implementation of a SCM system.The results of a simulation experiment regarding SCM implementation options illustrate and verify the theoretical findings and confirm the general notion that the less informed party is obliged to pay information rent to the better-informed party.展开更多
文摘The paper is undertaken with the objective of describing a new method for treating ductile cast iron in a ladle process, where the main objective is to minimize formation of eutectic carbides and shrinkage porosity during solidification. The suppression of carbide formation is associated with the nucleating properties of the nodularizer and inoculant alloys. By nucleating properties it is understood the number and potency of nuclei formed by an alloy addition. The nodularizer and inoculant additions also influence ductile iron solidification shrinkage. Some alloys may give good protection against shrinkage while others tend to promote more shrinkage. The use of various rare earth elements is found to have a pronounced impact on these conditions. It has been discovered that the use of pure lanthanum as the primary rare earth source in the magnesium ferrosilicon nodularizer surprisingly further improves the performance of the ductile iron ladle treatment method compared to similar methods using cerium or mishmetal bearing nodularizers. The nucleating properties are substantially improved and the risk for carbides (chill) and shrinkage formation in the sandwich or tundish ladle treated ductile iron is then minimized. The paper describes this new ladle treatment concept in detail, and gives examples from successful testing of the new nodularizing technology and how it simultaneously affects and minimizes critical ductile iron chill and shrinkage tendencies.
文摘The optimization investment policy decision of SCM-Supply Chain Management-implementation has been analysed under symmetric and asymmetric information conditions. For both conditions, SCM implementation options’ decision optimizing models have been developed. In these models, both clients and vendors try to pursue their own benefits. Based upon the principal-agent theory, the models show to what extent a principal (a client) needs to pay more to an agent (a vendor) in a context of asymmetric information. For the client, it is important to understand the extra costs to be able to adopt effective strategies to stimulate a vendor to perform an optimal implementation of a SCM system. The results of a simulation experiment regarding SCM implementation options illustrate and verify the theoretical findings and confirm the general notion that the less informed party is obliged to pay information rent to the better-informed party.
文摘The hybrid power-and voltage-based synchronization control method has shown potential for enhancing the stability of grid-forming(GFM)inverters.However,its effectiveness may be compromised if other control loops are not properly designed.To address the control-loop interactions,this paper presents a design-oriented analysis method for multiloop-controlled GFM inverters.The method begins by identifying the dominant oscillation modes through modal analysis.The sensitivities of damping ratios to control parameters are then determined for the dominant modes,which allows for characterization of control-loop interactions.A co-design method of GFM control is next developed based on the sensitivity analysis.Lastly,simulations and experimental results are presented to confirm the effectiveness of the method.
基金The first author was supported by China Scholarship Council(CSC)(201706080020)from the Ministry of Education of China and expresses his appreciation to CSC for their financial support。
文摘A T-shape tube hydraulic bulge test under axial feeding force is carried out to characterize the mechanical properties of EN AW 5049-O and 6060-O aluminium alloys.The punch displacement,T-branch height and axial compressive force are recorded online during the experiment.An intelligent inverse identification framework combining the finite element method and numerical optimization algorithm is developed to determine material parameters by fitting simulated results to the experimental data iteratively.The identified constitutive parameters using the inverse modelling technique are compared with those determined by the theoretical analysis and uniaxial tensile test.The comparison shows that the predicted bulge height and punch force based on the material parameters obtained by the three methods are different and the inverse strategy produces the smallest gap between numerical and experimental values.It is possible to conclude that the hydraulic bulge test can be applied to characterize the stress-strain curve of tubular materials at the large strain scope,and the automatic inverse framework is a more accurate post-processing procedure to identify material constitutive parameters compared with the classical analytical model.
基金2021 Ph.D.Program of Hainan Normal University(RC2100004363)。
文摘Pollution cost control is key to solve pollution problem.The paper takes pollution control cost of pollution control contract between management authority and pollutant discharge enterprise as research object,considers pollution control quality level,pollution control quality inspection and pollution control cost model,and establishes pollution control cost model of management authority and pollutant discharge enterprise,including rational constraints of pollutant discharge enterprise.And it analyzes principal-agent relationship between the two under condition of asymmetric information,and un-observability of pollution control level is shown as hiding information of sewage enterprises.In essence,it is problem of adverse selection in principal-agent.Pollution control cost of management is objective function.The first order condition of pollution control cost of sewage enterprise is transformed into state space equation,and optimal control of problem is solved by using maximum principle.In particular,management authority,as principal,uses pollution control provisions to reward,punish and encourage pollutant discharge enterprises as agents.
基金Supported by the Social Science Foundation of China(18BJL017)the Natural Science Foundation of Liaoning Science and Technology Bureau(20170540439)
文摘The optimization investment policy decision of SCM-supply chain management-implementation has been analysed under symmetric and asymmetric information conditions.For both conditions,SCM implementation optional decision optimizing models have been developed.In these models,both clients and vendors try to pursue their own benefits.Based upon the principal-agent theory,the models show to what extent a principal(a client)needs to pay more to an agent(a vendor)in a context of asymmetric information.For the client it is important to understand the extra costs to be able to adopt effective strategies to stimulate a vendor to perform an optimal implementation of a SCM system.The results of a simulation experiment regarding SCM implementation options illustrate and verify the theoretical findings and confirm the general notion that the less informed party is obliged to pay information rent to the better-informed party.
