Steam cracking is the dominant technology for producing light olefins,which are believed to be the foundation of the chemical industry.Predictive models of the cracking process can boost production efficiency and prof...Steam cracking is the dominant technology for producing light olefins,which are believed to be the foundation of the chemical industry.Predictive models of the cracking process can boost production efficiency and profit margin.Rapid advancements in machine learning research have recently enabled data-driven solutions to usher in a new era of process modeling.Meanwhile,its practical application to steam cracking is still hindered by the trade-off between prediction accuracy and computational speed.This research presents a framework for data-driven intelligent modeling of the steam cracking process.Industrial data preparation and feature engineering techniques provide computational-ready datasets for the framework,and feedstock similarities are exploited using k-means clustering.We propose LArge-Residuals-Deletion Multivariate Adaptive Regression Spline(LARD-MARS),a modeling approach that explicitly generates output formulas and eliminates potentially outlying instances.The framework is validated further by the presentation of clustering results,the explanation of variable importance,and the testing and comparison of model performance.展开更多
An analytical model for predicting the corrosion-induced cracking of concrete cover of reinforced concrete(RC) structures was developed.The effects of influence factors such as practical initial defects,corrosion rate...An analytical model for predicting the corrosion-induced cracking of concrete cover of reinforced concrete(RC) structures was developed.The effects of influence factors such as practical initial defects,corrosion rate,strength and elastic modulus of concrete on the corrosion-induced cracking of concrete cover were investigated.It was found that the size of practical initial defects was the most effective factor.Therefore,improving the compactness of concrete is an effective way to improve the durability of RC structures.It was also demonstrated that the accelerated corrosion tests may be unfavorable in the study of the relationship between cracking time and crack width.展开更多
The basic equations of the representation of plasticity at an interface crack by an inclined strip yield superdislocation model are derived. With a special combination of the material properties and small-scale yieldi...The basic equations of the representation of plasticity at an interface crack by an inclined strip yield superdislocation model are derived. With a special combination of the material properties and small-scale yielding case, the problem is reduced to an algebraic equation in an unknown, the ratio of the plastic zone size. Some discussions on the limitations of this model are presented.展开更多
The paper mainly focuses on the digital pulse width modulation (DPWM) control techniques for high performance power electronic circuit design. The problem to be solved in this study addresses the DPWM converter design...The paper mainly focuses on the digital pulse width modulation (DPWM) control techniques for high performance power electronic circuit design. The problem to be solved in this study addresses the DPWM converter design for DC to DC conversion process. The control techniques have been utilized the Fuzzy Logic Rules Base method for proposed SIMULINK model of high performance power electronic circuit. The analytical calculations for real circuit design have been completed based on the mathematical modeling of the system. The results from the developed SIMULINK model confirm the target specifications of the high performance condition for power electronic circuit which was met the objective of this study. The numerical results have been carried out with the help of MATLAB/SIMULINK.展开更多
The authors have proposed the calculation method of bridging law,that is expressed by tensile stress–crack width relationship,considering the influence of fiber orientation in FRCC(fiber-reinforced cementitious compo...The authors have proposed the calculation method of bridging law,that is expressed by tensile stress–crack width relationship,considering the influence of fiber orientation in FRCC(fiber-reinforced cementitious composite).The objective of this study is to propose a new tri-linear model that expresses the bridging law considering fiber orientation.The parameters that give the characteristic points of the tri-linear model are proposed as functions of orientation intensity.The bending test,in which the specimens are fabricated by three different casting methods,is conducted to verify the adaptability of the proposed model.The results of section analysis using the proposed model can present the difference of bending strength due to the fiber orientation.展开更多
针对永磁直流无刷电机(brushless DC motor,BLDCM)转矩脉动问题,基于两相导通星形三相六状态工作方式的永磁直流无刷电机数学模型,提出了5种不同的常用PWM调制方式。详细分析了这5种PWM调制方式对电机换相转矩脉动的不同影响并相互比较...针对永磁直流无刷电机(brushless DC motor,BLDCM)转矩脉动问题,基于两相导通星形三相六状态工作方式的永磁直流无刷电机数学模型,提出了5种不同的常用PWM调制方式。详细分析了这5种PWM调制方式对电机换相转矩脉动的不同影响并相互比较。根据公式推导得出采用PWM-ON调制方式可使直流无刷电机具有较小的转矩脉动。以TMS320F1812 DSP为控制核心,以180 W小型永磁直流无刷电机为控制对象进行了实验研究。利用DSP分别产生5种PWM调制方式波形并配合模糊PI控制器对电机进行控制。测得了相应的5种PWM调制方式下的相电流波形图。实验结果表明采用PWM-ON调制方式较理想,能够有效地抑制电机的换相转矩脉动。实验结果证明了理论分析的正确性。展开更多
基金supported by the National Key Research and Development Program of China(2021 YFB 4000500,2021 YFB 4000501,and 2021 YFB 4000502)。
文摘Steam cracking is the dominant technology for producing light olefins,which are believed to be the foundation of the chemical industry.Predictive models of the cracking process can boost production efficiency and profit margin.Rapid advancements in machine learning research have recently enabled data-driven solutions to usher in a new era of process modeling.Meanwhile,its practical application to steam cracking is still hindered by the trade-off between prediction accuracy and computational speed.This research presents a framework for data-driven intelligent modeling of the steam cracking process.Industrial data preparation and feature engineering techniques provide computational-ready datasets for the framework,and feedstock similarities are exploited using k-means clustering.We propose LArge-Residuals-Deletion Multivariate Adaptive Regression Spline(LARD-MARS),a modeling approach that explicitly generates output formulas and eliminates potentially outlying instances.The framework is validated further by the presentation of clustering results,the explanation of variable importance,and the testing and comparison of model performance.
基金Supported by National Natural Science Foundation of China (No. 50908148)Natural Science Foundation for Team Project of Guangdong Province(No. 9351806001000001)+1 种基金Scientific Research Foundation for Returned Overseas Chinese Scholars,Ministry of Education(41 Batch)Open Fund of State Key Laboratory of Coastal and Of fshore Engineering of Dalian University of Technology (No. LP1111)
文摘An analytical model for predicting the corrosion-induced cracking of concrete cover of reinforced concrete(RC) structures was developed.The effects of influence factors such as practical initial defects,corrosion rate,strength and elastic modulus of concrete on the corrosion-induced cracking of concrete cover were investigated.It was found that the size of practical initial defects was the most effective factor.Therefore,improving the compactness of concrete is an effective way to improve the durability of RC structures.It was also demonstrated that the accelerated corrosion tests may be unfavorable in the study of the relationship between cracking time and crack width.
基金Visiting Research Fellow in Institute of Industrial Science.University of Tokyo,supported by Japan Society for the Promotion of Science.
文摘The basic equations of the representation of plasticity at an interface crack by an inclined strip yield superdislocation model are derived. With a special combination of the material properties and small-scale yielding case, the problem is reduced to an algebraic equation in an unknown, the ratio of the plastic zone size. Some discussions on the limitations of this model are presented.
文摘The paper mainly focuses on the digital pulse width modulation (DPWM) control techniques for high performance power electronic circuit design. The problem to be solved in this study addresses the DPWM converter design for DC to DC conversion process. The control techniques have been utilized the Fuzzy Logic Rules Base method for proposed SIMULINK model of high performance power electronic circuit. The analytical calculations for real circuit design have been completed based on the mathematical modeling of the system. The results from the developed SIMULINK model confirm the target specifications of the high performance condition for power electronic circuit which was met the objective of this study. The numerical results have been carried out with the help of MATLAB/SIMULINK.
文摘The authors have proposed the calculation method of bridging law,that is expressed by tensile stress–crack width relationship,considering the influence of fiber orientation in FRCC(fiber-reinforced cementitious composite).The objective of this study is to propose a new tri-linear model that expresses the bridging law considering fiber orientation.The parameters that give the characteristic points of the tri-linear model are proposed as functions of orientation intensity.The bending test,in which the specimens are fabricated by three different casting methods,is conducted to verify the adaptability of the proposed model.The results of section analysis using the proposed model can present the difference of bending strength due to the fiber orientation.
文摘针对永磁直流无刷电机(brushless DC motor,BLDCM)转矩脉动问题,基于两相导通星形三相六状态工作方式的永磁直流无刷电机数学模型,提出了5种不同的常用PWM调制方式。详细分析了这5种PWM调制方式对电机换相转矩脉动的不同影响并相互比较。根据公式推导得出采用PWM-ON调制方式可使直流无刷电机具有较小的转矩脉动。以TMS320F1812 DSP为控制核心,以180 W小型永磁直流无刷电机为控制对象进行了实验研究。利用DSP分别产生5种PWM调制方式波形并配合模糊PI控制器对电机进行控制。测得了相应的5种PWM调制方式下的相电流波形图。实验结果表明采用PWM-ON调制方式较理想,能够有效地抑制电机的换相转矩脉动。实验结果证明了理论分析的正确性。
