in this paper, an electromechanically coupled mathematic model of multi-roller driving system for belt conveyor is set up, and the computing equations for dynamic displacement and dynamic tension of the conveyor are a...in this paper, an electromechanically coupled mathematic model of multi-roller driving system for belt conveyor is set up, and the computing equations for dynamic displacement and dynamic tension of the conveyor are also formulated when the hoister is used for straining. Based on the belt conveyor of main inclined shaft in Chengzhuang coal mine, the driving torque, driving power and starting-speed characteristic of each electric motor are studied and measured when multi-roller variable-frequency drive (power distribution 2∶1) is used. The optimal control and the optimal starting-acceleration of the multi-roller variable-frequency drive are determined by a large number of industrial experiments and theoretical calculations.展开更多
The multi-roller straightening process of section steel is analyzed by the springback theory of small curva- ture plane bending. The theoretical analysis results prove the curvature unification in straightening proces...The multi-roller straightening process of section steel is analyzed by the springback theory of small curva- ture plane bending. The theoretical analysis results prove the curvature unification in straightening process and clear- ly reveal the principle of the multi-roller straightening process. The principle can be described as~ the initial curva- tures are reduced by several times anti-bendingl meanwhile the initial curvature differences are diminished and the residual curvatures are unified~ finally, the member after curvature unification is straightened by the last anti-ben- ding. With the plastic region ratios becoming larger, the initial curvatures are more easily unified in straightening process. Based on the plastic region ratios and the required number of roller systems for unifying the initial curva- tures, the large deformation straightening strategy and the small deformation straightening strategy are redefined. The new definition provides an important theoretical basis for setting reliable reduction rules. Through the theoretical analysis results, a new straightener design philosophy is proposed to improve the straightening quality and further increase the adjustment precision as well as the flexibility of the last roller system. The adjustable end roller emerges as the times required, achieving a good effect in practical application.展开更多
Group role assignment(GRA)is originally a complex problem in role-based collaboration(RBC).The solution to GRA provides modelling techniques for more complex problems.GRA with constraints(GRA+)is categorized as a clas...Group role assignment(GRA)is originally a complex problem in role-based collaboration(RBC).The solution to GRA provides modelling techniques for more complex problems.GRA with constraints(GRA+)is categorized as a class of complex assignment problems.At present,there are few generally efficient solutions to this category of problems.Each special problem case requires a specific solution.Group multi-role assignment(GMRA)and GRA with conflicting agents on roles(GRACAR)are two problem cases in GRA+.The contributions of this paper include:1)The formalization of a new problem of GRA+,called group multi-role assignment with conflicting roles and agents(GMAC),which is an extension to the combination of GMRA and GRACAR;2)A practical solution based on an optimization platform;3)A sufficient condition,used in planning,for solving GMAC problems;and 4)A clear presentation of the benefits in avoiding conflicts when dealing with GMAC.The proposed methods are verified by experiments,simulations,proofs and analysis.展开更多
Development of man-packable,versatile marine surface vehicle with ability to rescue a drowning victim and also capable of carrying mission specific sensor is explored.Design thinking methodology is implemented by usin...Development of man-packable,versatile marine surface vehicle with ability to rescue a drowning victim and also capable of carrying mission specific sensor is explored.Design thinking methodology is implemented by using existing equipment/platform with the addition of external attachment to make it a functional product.Iterative prototyping process with extensive testing to achieve user-centric solution.Individual prototypes and their possible sub-configurations with their integration and characteristics are studied and compared with numerical model,inferences obtained are utilised to improve for the next iteration.A novel hinge-clamp assembly enables this marine surface vehicle to operate in the event of an overturn,this phenomenon is further studied with the aid of a mathematical model(Pendulum in a fluid).This research project aims to demonstrate a multi-role unmanned surface vehicle.展开更多
The paper first introduces the multi-roles of College English teachers, from the knowledge instillers to the designers and organizers of classroom activities, the participants of learning English, information counselo...The paper first introduces the multi-roles of College English teachers, from the knowledge instillers to the designers and organizers of classroom activities, the participants of learning English, information counselors and emotional supporters, and the models of morality. Based on this, the paper makes a detailed analysis of the multi-role effects which can not only stimulate students＇ creativity and improve their self-learning ability, but also adapt to the reform of College English teaching.展开更多
文摘in this paper, an electromechanically coupled mathematic model of multi-roller driving system for belt conveyor is set up, and the computing equations for dynamic displacement and dynamic tension of the conveyor are also formulated when the hoister is used for straining. Based on the belt conveyor of main inclined shaft in Chengzhuang coal mine, the driving torque, driving power and starting-speed characteristic of each electric motor are studied and measured when multi-roller variable-frequency drive (power distribution 2∶1) is used. The optimal control and the optimal starting-acceleration of the multi-roller variable-frequency drive are determined by a large number of industrial experiments and theoretical calculations.
基金Item Sponsored by National Natural Science Foundation of China(51178452)
文摘The multi-roller straightening process of section steel is analyzed by the springback theory of small curva- ture plane bending. The theoretical analysis results prove the curvature unification in straightening process and clear- ly reveal the principle of the multi-roller straightening process. The principle can be described as~ the initial curva- tures are reduced by several times anti-bendingl meanwhile the initial curvature differences are diminished and the residual curvatures are unified~ finally, the member after curvature unification is straightened by the last anti-ben- ding. With the plastic region ratios becoming larger, the initial curvatures are more easily unified in straightening process. Based on the plastic region ratios and the required number of roller systems for unifying the initial curva- tures, the large deformation straightening strategy and the small deformation straightening strategy are redefined. The new definition provides an important theoretical basis for setting reliable reduction rules. Through the theoretical analysis results, a new straightener design philosophy is proposed to improve the straightening quality and further increase the adjustment precision as well as the flexibility of the last roller system. The adjustable end roller emerges as the times required, achieving a good effect in practical application.
基金supported in part by Natural Sciences and Engineering Research Council,Canada(NSERC)(RGPIN-2018-04818)the funding from the Innovation for Defence Excellence and Security(IDEaS)Program from the Canadian Department of National Defence(DND)。
文摘Group role assignment(GRA)is originally a complex problem in role-based collaboration(RBC).The solution to GRA provides modelling techniques for more complex problems.GRA with constraints(GRA+)is categorized as a class of complex assignment problems.At present,there are few generally efficient solutions to this category of problems.Each special problem case requires a specific solution.Group multi-role assignment(GMRA)and GRA with conflicting agents on roles(GRACAR)are two problem cases in GRA+.The contributions of this paper include:1)The formalization of a new problem of GRA+,called group multi-role assignment with conflicting roles and agents(GMAC),which is an extension to the combination of GMRA and GRACAR;2)A practical solution based on an optimization platform;3)A sufficient condition,used in planning,for solving GMAC problems;and 4)A clear presentation of the benefits in avoiding conflicts when dealing with GMAC.The proposed methods are verified by experiments,simulations,proofs and analysis.
文摘Development of man-packable,versatile marine surface vehicle with ability to rescue a drowning victim and also capable of carrying mission specific sensor is explored.Design thinking methodology is implemented by using existing equipment/platform with the addition of external attachment to make it a functional product.Iterative prototyping process with extensive testing to achieve user-centric solution.Individual prototypes and their possible sub-configurations with their integration and characteristics are studied and compared with numerical model,inferences obtained are utilised to improve for the next iteration.A novel hinge-clamp assembly enables this marine surface vehicle to operate in the event of an overturn,this phenomenon is further studied with the aid of a mathematical model(Pendulum in a fluid).This research project aims to demonstrate a multi-role unmanned surface vehicle.
文摘The paper first introduces the multi-roles of College English teachers, from the knowledge instillers to the designers and organizers of classroom activities, the participants of learning English, information counselors and emotional supporters, and the models of morality. Based on this, the paper makes a detailed analysis of the multi-role effects which can not only stimulate students＇ creativity and improve their self-learning ability, but also adapt to the reform of College English teaching.
