Electric vehicles (EVs) offer great potential to move from fossil fuel dependency in transport once some of the technical barriers related to battery reliability and grid integration are resolved. The European Union h...Electric vehicles (EVs) offer great potential to move from fossil fuel dependency in transport once some of the technical barriers related to battery reliability and grid integration are resolved. The European Union has set a target to achieve a 10% reduction in greenhouse gas emissions by 2020 relative to 2005 levels. This target is binding in all the European Union member states. If electric vehicle issues are overcome then the challenge is to use as much renewable energy as possible to achieve this target. In this paper, the impacts of electric vehicle charged in the all-Ireland single wholesale electricity market after the 2020 deadline passes is investigated using a power system dispatch model. For the purpose of this work it is assumed that a 10% electric vehicle target in the Republic of Ireland is not achieved, but instead 8% is reached by 2025 considering the slow market uptake of electric vehicles. Our experimental study shows that the increasing penetration of EVs could contribute to approach the target of the EU and Ireland government on emissions reduction, regardless of different charging scenarios. Furthermore, among various charging scenarios, the off-peak charging is the best approach, contributing 2.07% to the target of 10% reduction of Greenhouse gas emissions by 2025.展开更多
Inspired by the dynamic wet adhesive systems in nature,various artificial adhesive surfaces have been developed but still face different challenges.Crucially,the theoretical mechanics of wet adhesives has never been s...Inspired by the dynamic wet adhesive systems in nature,various artificial adhesive surfaces have been developed but still face different challenges.Crucially,the theoretical mechanics of wet adhesives has never been sufficiently revealed.Here,we develop a novel adhesive mechanism for governing wet adhesion and investigate the biological models of honeybee arolium for reproducing the natural wet adhesive systems.Micro-nano structures of honeybee arolium and arolium-prints were observed by Cryogenic scanning electron microscopy(Cryo-SEM),and the air pockets were found in the contact interface notably.Subsequently,the adhesive models with a three-phase composite interface(including air pockets,liquid secretion,and hexagonal frames of arolium),were formed to analyze the wet adhesion of honeybee arolium.The results of theoretical calculations and experiments indicated an enhanced adhesive mechanism of the honeybee by liquid self-sucking effects and air-embolism effects.Under these effects,normal and shear adhesion can be adjusted by controlling the proportion of liquid secretion and air pockets in the contact zone.Notably,the air-embolism effects contribute to the optimal coupling of smaller normal adhesion with greater shear adhesion,which is beneficial for the high stride frequency of honeybees.These works can provide a fresh perspective on the development of bio-inspired wet adhesive surfaces.展开更多
Humans have long desired but never achieved the capacity to climb walls.The fundamental reason is that human hands and feet cannot climb vertical walls like geckos and bees.Animals lacking an adhesive structure can us...Humans have long desired but never achieved the capacity to climb walls.The fundamental reason is that human hands and feet cannot climb vertical walls like geckos and bees.Animals lacking an adhesive structure can use the body’s dynamic effect to climb walls.Here we investigated the dynamic wall climbing behavior of individuals who cannot remain stationary on the vertical wall.Taking the domestic cat as the experimental object,we constructed an experimental platform as the obstacle for the cat to climb the wall.Our research indicated that domestic cats must meet the following physical conditions to do dynamic vertical wall climbing:vertical obstacles must have nonvertical surfaces,a horizontal run-up,and contact with nonvertical surfaces before the vertical speed reduces to zero.Here we proposed a dynamic vertical wall climbing model with three contact states based on an investigation of domestic cats’dynamic wall climbing behavior and the LIP model.The motion range of the LIP model’s generalized angular coordinates varies depending on the contact state.The horizontal run-up action can improve the jumping height and obtain horizontal speed.When making contact with the vertical surface of the obstacle,the motion inertia in the horizontal direction can produce a reaction force on the contact surface,which can compensate for the influence of some gravity.This alternating contact strategy lets cats switch different initial and end contact angles.This investigation clarifies the essential process underlying animals’dynamic vertical wall climbing and establishes the theoretical foundation for the legged robot to do dynamic vertical wall climbing.展开更多
Economic and environmental load dispatch aims to determine the amount of electricity generated from power plants to meet load demand while minimizing fossil fuel costs and air pollution emissions subject to operationa...Economic and environmental load dispatch aims to determine the amount of electricity generated from power plants to meet load demand while minimizing fossil fuel costs and air pollution emissions subject to operational and licensing requirements.These two scheduling problems are commonly formulated with non-smooth cost functions respectively considering various effects and constraints,such as the valve point effect,power balance and ramprate limits.The expected increase in plug-in electric vehicles is likely to see a significant impact on the power system due to high charging power consumption and significant uncertainty in charging times.In this paper,multiple electric vehicle charging profiles are comparatively integrated into a 24-hour load demand in an economic and environment dispatch model.Self-learning teaching-learning based optimization(TLBO)is employed to solve the non-convex non-linear dispatch problems.Numerical results onwell-known benchmark functions,as well as test systems with different scales of generation units show the significance of the new scheduling method.展开更多
Warehouse scheduling efficiency has to do with the length-height ratio of location(LHRL) to some extent, which hasn't been well investigated until now. In this paper a mathematic model is built by analyzing the re...Warehouse scheduling efficiency has to do with the length-height ratio of location(LHRL) to some extent, which hasn't been well investigated until now. In this paper a mathematic model is built by analyzing the relation between the travel time of the stacker and LHRL. Meanwhile, warehouse scheduling strategy is studied combining with the project on the automatic production line of an enterprise, and a warehouse scheduling strategy is proposed based on index of quality(IoQ) parameters. Besides, the process of getting the value of IoQ is also simplified with the idea of sparse matrix. Finally, the IoQ scheduling strategy is compared with random strategy and First Come First Out strategy in different LHRLs. The simulation results show that the IoQ scheduling strategy not only improves the quality of the product effectively, but also improves the efficiency of the scheduling substantially.展开更多
文摘Electric vehicles (EVs) offer great potential to move from fossil fuel dependency in transport once some of the technical barriers related to battery reliability and grid integration are resolved. The European Union has set a target to achieve a 10% reduction in greenhouse gas emissions by 2020 relative to 2005 levels. This target is binding in all the European Union member states. If electric vehicle issues are overcome then the challenge is to use as much renewable energy as possible to achieve this target. In this paper, the impacts of electric vehicle charged in the all-Ireland single wholesale electricity market after the 2020 deadline passes is investigated using a power system dispatch model. For the purpose of this work it is assumed that a 10% electric vehicle target in the Republic of Ireland is not achieved, but instead 8% is reached by 2025 considering the slow market uptake of electric vehicles. Our experimental study shows that the increasing penetration of EVs could contribute to approach the target of the EU and Ireland government on emissions reduction, regardless of different charging scenarios. Furthermore, among various charging scenarios, the off-peak charging is the best approach, contributing 2.07% to the target of 10% reduction of Greenhouse gas emissions by 2025.
基金supported by the National Key R&D Program of China(2021YFB3400200)the Beijing Natural Science Foundation(3212012)+2 种基金the National Natural Science Foundation of China(52075038)the Opening Project of the Key Laboratory of Bionic Engineering(Ministry of Education),Jilin University(KF20200001)the Opening Project of State Key Laboratory of Tribology,Tsinghua University(SKLTKF20B06)。
文摘Inspired by the dynamic wet adhesive systems in nature,various artificial adhesive surfaces have been developed but still face different challenges.Crucially,the theoretical mechanics of wet adhesives has never been sufficiently revealed.Here,we develop a novel adhesive mechanism for governing wet adhesion and investigate the biological models of honeybee arolium for reproducing the natural wet adhesive systems.Micro-nano structures of honeybee arolium and arolium-prints were observed by Cryogenic scanning electron microscopy(Cryo-SEM),and the air pockets were found in the contact interface notably.Subsequently,the adhesive models with a three-phase composite interface(including air pockets,liquid secretion,and hexagonal frames of arolium),were formed to analyze the wet adhesion of honeybee arolium.The results of theoretical calculations and experiments indicated an enhanced adhesive mechanism of the honeybee by liquid self-sucking effects and air-embolism effects.Under these effects,normal and shear adhesion can be adjusted by controlling the proportion of liquid secretion and air pockets in the contact zone.Notably,the air-embolism effects contribute to the optimal coupling of smaller normal adhesion with greater shear adhesion,which is beneficial for the high stride frequency of honeybees.These works can provide a fresh perspective on the development of bio-inspired wet adhesive surfaces.
基金supported by the National Key R&D Program of China(2021YFB3400200)the National Natural Science Foundation of China(grant 52075038)+2 种基金the Beijing Natural Science Foundation(grant 3212012)the Opening Project of State Key Laboratory of Tribology,Tsinghua University(SKLTKF20B06)the Beijing Institute of Technology Research Fund Program for Young Scholars.
文摘Humans have long desired but never achieved the capacity to climb walls.The fundamental reason is that human hands and feet cannot climb vertical walls like geckos and bees.Animals lacking an adhesive structure can use the body’s dynamic effect to climb walls.Here we investigated the dynamic wall climbing behavior of individuals who cannot remain stationary on the vertical wall.Taking the domestic cat as the experimental object,we constructed an experimental platform as the obstacle for the cat to climb the wall.Our research indicated that domestic cats must meet the following physical conditions to do dynamic vertical wall climbing:vertical obstacles must have nonvertical surfaces,a horizontal run-up,and contact with nonvertical surfaces before the vertical speed reduces to zero.Here we proposed a dynamic vertical wall climbing model with three contact states based on an investigation of domestic cats’dynamic wall climbing behavior and the LIP model.The motion range of the LIP model’s generalized angular coordinates varies depending on the contact state.The horizontal run-up action can improve the jumping height and obtain horizontal speed.When making contact with the vertical surface of the obstacle,the motion inertia in the horizontal direction can produce a reaction force on the contact surface,which can compensate for the influence of some gravity.This alternating contact strategy lets cats switch different initial and end contact angles.This investigation clarifies the essential process underlying animals’dynamic vertical wall climbing and establishes the theoretical foundation for the legged robot to do dynamic vertical wall climbing.
基金The authors would also like to thank UK EPSRC under grant EP/L001063/1 and China NSFC under grants 51361130153 and 61273040.
文摘Economic and environmental load dispatch aims to determine the amount of electricity generated from power plants to meet load demand while minimizing fossil fuel costs and air pollution emissions subject to operational and licensing requirements.These two scheduling problems are commonly formulated with non-smooth cost functions respectively considering various effects and constraints,such as the valve point effect,power balance and ramprate limits.The expected increase in plug-in electric vehicles is likely to see a significant impact on the power system due to high charging power consumption and significant uncertainty in charging times.In this paper,multiple electric vehicle charging profiles are comparatively integrated into a 24-hour load demand in an economic and environment dispatch model.Self-learning teaching-learning based optimization(TLBO)is employed to solve the non-convex non-linear dispatch problems.Numerical results onwell-known benchmark functions,as well as test systems with different scales of generation units show the significance of the new scheduling method.
基金supported by the National Natural Science Foundation of China (Grant Nos. 61074032 and 61273040)the Project of Science and Technology Commission of Shanghai Municipality (Grant No. 10JC1405000)the Shanghai Rising-Star Program (Grant No. 12QA1401100)
文摘Warehouse scheduling efficiency has to do with the length-height ratio of location(LHRL) to some extent, which hasn't been well investigated until now. In this paper a mathematic model is built by analyzing the relation between the travel time of the stacker and LHRL. Meanwhile, warehouse scheduling strategy is studied combining with the project on the automatic production line of an enterprise, and a warehouse scheduling strategy is proposed based on index of quality(IoQ) parameters. Besides, the process of getting the value of IoQ is also simplified with the idea of sparse matrix. Finally, the IoQ scheduling strategy is compared with random strategy and First Come First Out strategy in different LHRLs. The simulation results show that the IoQ scheduling strategy not only improves the quality of the product effectively, but also improves the efficiency of the scheduling substantially.
