Coupled thermo-mechanical model was used to investigate the effects of the pin diameter, the shoulder diameter and the in conical angle on the heat generations, the material deformations and the energy histories in fr...Coupled thermo-mechanical model was used to investigate the effects of the pin diameter, the shoulder diameter and the in conical angle on the heat generations, the material deformations and the energy histories in friction stir welding（FSW） of AA2024-T3 alloy. Results indicate that the shoulder-plate contact area takes more important contribution to the heat generation than the pin-plate contact area. The increase of the shoulder diameter or the decrease of the pin diameter can lead to the increase of the welding temperature in FSW, but the change of shoulder size is more important. Compared to the cases in FSW of AA6061-T6, the input power is obviously increased in FSW of AA2024-T3 and the ratio of the plastic dissipation to the friction dissipation becomes decreased.展开更多
In rechargeable wireless sensor networks, a sensor cannot be always benefi cial to conserve energy when a network can harvest excessive energy from the environment due to its energy replenished continually and limited...In rechargeable wireless sensor networks, a sensor cannot be always benefi cial to conserve energy when a network can harvest excessive energy from the environment due to its energy replenished continually and limited energy storage capacity. Therefore, surplus energy of a node can be utilized for strengthening packet delivery efficiency and improving data collection rate. In this work, we propose an algorithm to compute an upper data generation rate that maximizes it as an optimization problem for a network with multiple sinks, which is formulated as a linear programming problem. Subsequently, a dual problem by introducing Lagrange multipliers is constructed, and subgradient algorithms are used to solve it in a distributed manner. The resulting algorithms are guaranteed to converge to an optimal data generation rate, which are illustrated by an example in which an optimum data generation rate is computed for a network of randomly distributed nodes. Through extensive simulation and experiments, we demonstrate our algorithm is efficient to maximize data collection rate in rechargeable wireless sensor networks.展开更多
Effects of the amplitude(± 2, ± 4, ± 6, and ± 8) and frequency(2, 4, and 8 d) of salinity fluctuation on the body composition and energy budget of juvenile tongue sole(Cynoglossus semilaevis) were ...Effects of the amplitude(± 2, ± 4, ± 6, and ± 8) and frequency(2, 4, and 8 d) of salinity fluctuation on the body composition and energy budget of juvenile tongue sole(Cynoglossus semilaevis) were investigated in a 64-d experiment. Results showed that the amplitude and frequency of salinity fluctuation had significant interaction and both substantially affected the final weight and specific growth rate of juvenile tongue sole. The tongue sole exhibited better growth in treatments with moderate amplitude and frequency of salinity fluctuation(amplitude ± 4–6; frequency 4–8 d) than in other treatments and the control. In terms of energy budget, salinity fluctuation strongly affected the proportions of energy components, including those deposited for growth and lost in respiration, feces, and excretion. Moderately amplitude and frequency of salinity fluctuationg that favored the growth of tongue sole partitioned more energy for growth and less energy for metabolism than the constant and other amplitude and frequency of salinity fluctuation. Average energy budget for tongue sole at moderately fluctuating salinity was determined to be 100C(food) = 30.92G(growth) + 10.30F(feces) + 6.77U(excretion) + 52.01R(respiration). Energetic advantage at moderately fluctuating salinity, including increased energy intake, high assimilation efficiency, reduced metabolism expenditure, and more energy partitioned into growth, might account for the enhancement of tongue sole growth. Commercial farmers are recommended to rear juvenile tongue sole with moderate salinity fluctuations for better growth performance of this species.展开更多
Consider the motion of immersed hypersurfaces driven by surface diffusion flow and give anlower bound on the life span of a smooth immersed solution, which depends only on how muchthe curvature of the initial surface ...Consider the motion of immersed hypersurfaces driven by surface diffusion flow and give anlower bound on the life span of a smooth immersed solution, which depends only on how muchthe curvature of the initial surface is concentrated in space.展开更多
基金Project(NCET-12-0075)supported by the Program for New Century Excellent Talents in University,ChinaProject supported by the Fundamental Research Funds for the Central Universities,China+2 种基金Projects(11172057,11232003)supported by the National Natural Science Foundation of ChinaProject(2011CB013401)supported by the National Basic Research Program of ChinaProject(2012AA050901)supported by the National High-Tech Research and Development Program of China
文摘Coupled thermo-mechanical model was used to investigate the effects of the pin diameter, the shoulder diameter and the in conical angle on the heat generations, the material deformations and the energy histories in friction stir welding（FSW） of AA2024-T3 alloy. Results indicate that the shoulder-plate contact area takes more important contribution to the heat generation than the pin-plate contact area. The increase of the shoulder diameter or the decrease of the pin diameter can lead to the increase of the welding temperature in FSW, but the change of shoulder size is more important. Compared to the cases in FSW of AA6061-T6, the input power is obviously increased in FSW of AA2024-T3 and the ratio of the plastic dissipation to the friction dissipation becomes decreased.
基金supported by The Natural Science Foundation of Jiangsu Province of China(Grant No.BK20141474)funded by China Postdoctoral Science Foundation(Grant No.2015M571639)+3 种基金three Projects Funded by The Jiangsu Planned Projects for Postdoctoral Research Funds(Grant No.1402018C)The Key Laboratory of Computer Network and Information Integration(Southeast University)Ministry of Education(Grant No.K93-9-2015-09C)The Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institutions
文摘In rechargeable wireless sensor networks, a sensor cannot be always benefi cial to conserve energy when a network can harvest excessive energy from the environment due to its energy replenished continually and limited energy storage capacity. Therefore, surplus energy of a node can be utilized for strengthening packet delivery efficiency and improving data collection rate. In this work, we propose an algorithm to compute an upper data generation rate that maximizes it as an optimization problem for a network with multiple sinks, which is formulated as a linear programming problem. Subsequently, a dual problem by introducing Lagrange multipliers is constructed, and subgradient algorithms are used to solve it in a distributed manner. The resulting algorithms are guaranteed to converge to an optimal data generation rate, which are illustrated by an example in which an optimum data generation rate is computed for a network of randomly distributed nodes. Through extensive simulation and experiments, we demonstrate our algorithm is efficient to maximize data collection rate in rechargeable wireless sensor networks.
基金supported by the National Great Project of Scientific and Technical Supporting Programs of China (Grant No. 2011BAD13B03)]the Program for Excellent Youth Foundation of Shandong province (Grant No. JQ201009)the Public Science and Technology Research Funds Projects of Ocean, State Oceanic Administration of the People’s Republic of China (Grant No. 200905020)
文摘Effects of the amplitude(± 2, ± 4, ± 6, and ± 8) and frequency(2, 4, and 8 d) of salinity fluctuation on the body composition and energy budget of juvenile tongue sole(Cynoglossus semilaevis) were investigated in a 64-d experiment. Results showed that the amplitude and frequency of salinity fluctuation had significant interaction and both substantially affected the final weight and specific growth rate of juvenile tongue sole. The tongue sole exhibited better growth in treatments with moderate amplitude and frequency of salinity fluctuation(amplitude ± 4–6; frequency 4–8 d) than in other treatments and the control. In terms of energy budget, salinity fluctuation strongly affected the proportions of energy components, including those deposited for growth and lost in respiration, feces, and excretion. Moderately amplitude and frequency of salinity fluctuationg that favored the growth of tongue sole partitioned more energy for growth and less energy for metabolism than the constant and other amplitude and frequency of salinity fluctuation. Average energy budget for tongue sole at moderately fluctuating salinity was determined to be 100C(food) = 30.92G(growth) + 10.30F(feces) + 6.77U(excretion) + 52.01R(respiration). Energetic advantage at moderately fluctuating salinity, including increased energy intake, high assimilation efficiency, reduced metabolism expenditure, and more energy partitioned into growth, might account for the enhancement of tongue sole growth. Commercial farmers are recommended to rear juvenile tongue sole with moderate salinity fluctuations for better growth performance of this species.
基金Project supported by the National Natural Science Foundation of China(No.10071067)and the Jiangsu Provincial Natural Science Foundation of China.
文摘Consider the motion of immersed hypersurfaces driven by surface diffusion flow and give anlower bound on the life span of a smooth immersed solution, which depends only on how muchthe curvature of the initial surface is concentrated in space.
