Chromium ore fines containing coal (COFCC) can be rapidly heated by microwave to conduct the voluminal reduction, which lays a foundation of getting sponge ferrochromium powders with a lower content of C. Under the co...Chromium ore fines containing coal (COFCC) can be rapidly heated by microwave to conduct the voluminal reduction, which lays a foundation of getting sponge ferrochromium powders with a lower content of C. Under the conditions of COFCC with n(O)-n(C) (molar ratio) as 1.00-0.84 and n(SiO2)-n(CaO) as 1.00-0.39, the samples were heated by 10 kW microwave power to reach the given temperatures and held for different times respectively. The results show that the low-C-Cr ferrochromium metal phase in the reduced materials forms before the high-C-Cr ferrochromium metal phase does. With increasing temperature the C content of ferrochromium metals is in a positive correlation with the content of Cr. The C content of ferrochromium metal in reduced materials is 0-10.07% with an average value of 4.68%. With the increase of holding time the Cr content in ferrochromium metals is in a negative correlation with the content of C, while the content of Fe changes in the contrary way. In the microwave field the kinetic conditions of carburization are closely related with the temperature of microwave heating, holding time and carbon fitting ratio.展开更多
Proper solid waste disposal is an important socioeconomic concern for all developing countries.Municipalities have their own policies,individual approaches and methods to manage the solid wastes.They consider wastelan...Proper solid waste disposal is an important socioeconomic concern for all developing countries.Municipalities have their own policies,individual approaches and methods to manage the solid wastes.They consider wastelands outside the urban area as the best suitable for the solid waste disposal.Such improper site selection will create morphological changes that lead to environmental hazards in the urban and its surrounding areas.In this research,the site selection for urban solid waste disposal in the Coimbatore district used geographical information system(GIS)and multi-criteria decision analysis(MCDA).Thematic layers of lineament density,landuse/landcover,population density,groundwater depth,drainage density,slope,soil texture,geology and geomorphology were considered as primary criteria and weights for criteria,and sub-criteria were assigned by MCDA analysis.The resultant weight score was validated by consistency ratio so that the efficiency of the selected criteria was justified.The overlay analysis in GIS environment provides 17 potential zones in Coimbatore district,among which,four suitable sites were screened and refined with the help of field investigation and visual interpretation of satellite image.The result of landfill suitability map shows the effectiveness of the proposed method.展开更多
A novel flywheel energy storage （FES） motor/generator （M/G） was proposed for marine systems. The purpose was to improve the power quality of a marine power system （MPS） and strengthen the energy recycle. Two str...A novel flywheel energy storage （FES） motor/generator （M/G） was proposed for marine systems. The purpose was to improve the power quality of a marine power system （MPS） and strengthen the energy recycle. Two structures including the magnetic or non-magnetic inner-rotor were contrasted in the magnetostatic field by using finite element analysis （FEA）. By optimally designing the size parameters, the average speed of FEA results of was 17 200 r/m, and the current was controlled between 62 and 68 A in the transient field. The electrical machine electromagnetism design was further optimized by the FEA in the temperature field, to find the local overheating point under the normal operation condition and provide guidance for the cooling system. Finally, it can be concluded from the comprehensive physical field analysis that the novel redundant structure M/G can improve the efficiency of the M/G and maintain the stability of the MPS.展开更多
Fast and accurate identification of unknown pollution sources plays a crucial role in the emergency response and source control of air pollution.In this work,the applicability of a previously proposed two-step inversi...Fast and accurate identification of unknown pollution sources plays a crucial role in the emergency response and source control of air pollution.In this work,the applicability of a previously proposed two-step inversion method is investigated with sensitivity experiments and real data from the first release of the European Tracer Experiment(ETEX-1).The two-step inversion method is based on the principle of least squares and carries out additional model correction through the residual iterative process.To evaluate its performance,its retrieval results are compared with those of two other existing algorithms.It is shown that for those cases with richer measurements,all three methods are less sensitive to errors,while for cases where measurements are sparse,their retrieval accuracy will rapidly decrease as errors increase.From the results of sensitivity experiments,the new method provides higher estimation accuracy and a more stable performance than the other two methods.The new method presents the smallest maximum location error of 18.20 km when the amplitude of the measurement error increases to 100%,and 22.67 km when errors in the wind fields increase to 200%.Moreover,when applied to ETEX-1 data,the new method also exhibits good performance,with a location error of 4.71 km,which is the best estimation with respect to source location.展开更多
Facing the rapid development of economy and the increasingly fierce market competition, the role of logistics control is becoming far more important. Choosing the best way to play the role of logistics, improving over...Facing the rapid development of economy and the increasingly fierce market competition, the role of logistics control is becoming far more important. Choosing the best way to play the role of logistics, improving overall efficiency of the enterprise, reducing logistics cost and coping well with market competition, these things have great important practical significances. This article take hengtong transportation company as research object, giving the present situation of logistics cost and analyzing the causes of logistics cost increased year by year. At last, putting forward the concrete measures to realize better logistic control.展开更多
This study presents a new method to solve the difficult problem of precise machining a non-cylinder pinhole of a piston using embedded giant magnetostrictive material (GMM) in the component. We propose the finite elem...This study presents a new method to solve the difficult problem of precise machining a non-cylinder pinhole of a piston using embedded giant magnetostrictive material (GMM) in the component. We propose the finite element model of GMM smart component in electric, magnetic, and mechanical fields by step computation to optimize the design of GMM smart com-ponent. The proposed model is implemented by using COMSOL multi-physics V3.2a. The effects of the smart component on the deformation and the system resonance frequencies are studied. The results calculated by the model are in excellent agreement (relative errors are below 10%) with the experimental values.展开更多
基金Project(50474083) supported by the National Natural Science Foundation of ChinaProject supported by the Baoshan Iron & Steel Co. Ltd. of China
文摘Chromium ore fines containing coal (COFCC) can be rapidly heated by microwave to conduct the voluminal reduction, which lays a foundation of getting sponge ferrochromium powders with a lower content of C. Under the conditions of COFCC with n(O)-n(C) (molar ratio) as 1.00-0.84 and n(SiO2)-n(CaO) as 1.00-0.39, the samples were heated by 10 kW microwave power to reach the given temperatures and held for different times respectively. The results show that the low-C-Cr ferrochromium metal phase in the reduced materials forms before the high-C-Cr ferrochromium metal phase does. With increasing temperature the C content of ferrochromium metals is in a positive correlation with the content of Cr. The C content of ferrochromium metal in reduced materials is 0-10.07% with an average value of 4.68%. With the increase of holding time the Cr content in ferrochromium metals is in a negative correlation with the content of C, while the content of Fe changes in the contrary way. In the microwave field the kinetic conditions of carburization are closely related with the temperature of microwave heating, holding time and carbon fitting ratio.
文摘Proper solid waste disposal is an important socioeconomic concern for all developing countries.Municipalities have their own policies,individual approaches and methods to manage the solid wastes.They consider wastelands outside the urban area as the best suitable for the solid waste disposal.Such improper site selection will create morphological changes that lead to environmental hazards in the urban and its surrounding areas.In this research,the site selection for urban solid waste disposal in the Coimbatore district used geographical information system(GIS)and multi-criteria decision analysis(MCDA).Thematic layers of lineament density,landuse/landcover,population density,groundwater depth,drainage density,slope,soil texture,geology and geomorphology were considered as primary criteria and weights for criteria,and sub-criteria were assigned by MCDA analysis.The resultant weight score was validated by consistency ratio so that the efficiency of the selected criteria was justified.The overlay analysis in GIS environment provides 17 potential zones in Coimbatore district,among which,four suitable sites were screened and refined with the help of field investigation and visual interpretation of satellite image.The result of landfill suitability map shows the effectiveness of the proposed method.
基金Supported by the Fundamental Research Funds for the Central Universities under Grants Nos. HEUCF101706 and HEUCF111705
文摘A novel flywheel energy storage （FES） motor/generator （M/G） was proposed for marine systems. The purpose was to improve the power quality of a marine power system （MPS） and strengthen the energy recycle. Two structures including the magnetic or non-magnetic inner-rotor were contrasted in the magnetostatic field by using finite element analysis （FEA）. By optimally designing the size parameters, the average speed of FEA results of was 17 200 r/m, and the current was controlled between 62 and 68 A in the transient field. The electrical machine electromagnetism design was further optimized by the FEA in the temperature field, to find the local overheating point under the normal operation condition and provide guidance for the cooling system. Finally, it can be concluded from the comprehensive physical field analysis that the novel redundant structure M/G can improve the efficiency of the M/G and maintain the stability of the MPS.
基金supported by the National Key R&D Program of China[grant numbers 2017YFC1501803 and 2017YFC1502102].
文摘Fast and accurate identification of unknown pollution sources plays a crucial role in the emergency response and source control of air pollution.In this work,the applicability of a previously proposed two-step inversion method is investigated with sensitivity experiments and real data from the first release of the European Tracer Experiment(ETEX-1).The two-step inversion method is based on the principle of least squares and carries out additional model correction through the residual iterative process.To evaluate its performance,its retrieval results are compared with those of two other existing algorithms.It is shown that for those cases with richer measurements,all three methods are less sensitive to errors,while for cases where measurements are sparse,their retrieval accuracy will rapidly decrease as errors increase.From the results of sensitivity experiments,the new method provides higher estimation accuracy and a more stable performance than the other two methods.The new method presents the smallest maximum location error of 18.20 km when the amplitude of the measurement error increases to 100%,and 22.67 km when errors in the wind fields increase to 200%.Moreover,when applied to ETEX-1 data,the new method also exhibits good performance,with a location error of 4.71 km,which is the best estimation with respect to source location.
文摘Facing the rapid development of economy and the increasingly fierce market competition, the role of logistics control is becoming far more important. Choosing the best way to play the role of logistics, improving overall efficiency of the enterprise, reducing logistics cost and coping well with market competition, these things have great important practical significances. This article take hengtong transportation company as research object, giving the present situation of logistics cost and analyzing the causes of logistics cost increased year by year. At last, putting forward the concrete measures to realize better logistic control.
基金supported by the National Natural Science Foundation of China (No. 50575205)the Hi-Tech Research and Development (863) Program of China (Nos. 2006AA04Z233 and 2007AA04Z101)+1 种基金the Doctoral Foundation of Ministry of Education of China (No. 20070335204)the Zhejiang Provincial Natural Science Foundation of China (No. Z1080537)
文摘This study presents a new method to solve the difficult problem of precise machining a non-cylinder pinhole of a piston using embedded giant magnetostrictive material (GMM) in the component. We propose the finite element model of GMM smart component in electric, magnetic, and mechanical fields by step computation to optimize the design of GMM smart com-ponent. The proposed model is implemented by using COMSOL multi-physics V3.2a. The effects of the smart component on the deformation and the system resonance frequencies are studied. The results calculated by the model are in excellent agreement (relative errors are below 10%) with the experimental values.
