A flexible,multi-site tactile and thermal sensor(MTTS)based on polyvinylidene fluoride(resolution 50×50)is reported.It can be used to implement spatial mapping caused by tactile and thermal events and record the ...A flexible,multi-site tactile and thermal sensor(MTTS)based on polyvinylidene fluoride(resolution 50×50)is reported.It can be used to implement spatial mapping caused by tactile and thermal events and record the two-dimensional motion trajectory of a tracked target object.The output voltage and current signal are recorded as amapping by sensing the external pressure and thermal radiation stimulus,and the response distribution is dynamically observed on the three-dimensional interface.Through the mapping relationship between the established piezoelectric and pyroelectric signals,the piezoelectric component and the pyroelectric component are effectively extracted from the composite signals.The MTTS has a good sensitivity for tactile and thermal detection,and the electrodes have good synchronism.In addition,the signal interference is less than 9.5%and decreases as the pressure decreases after the distance between adjacent sites exceeds 200μm.The integration of MTTS and signal processing units has potential applications in human-machine interaction systems,health status detection and smart assistive devices.展开更多
Entropy analysis can help to identify the sources of entropy generation in a heat transfer process more accurately than other methods,such as energy efficiency analysis.This is because entropy analysis takes into acco...Entropy analysis can help to identify the sources of entropy generation in a heat transfer process more accurately than other methods,such as energy efficiency analysis.This is because entropy analysis takes into account the quality of energy as well as its quantity.Na-nofluids have already been shown to have superior heat transfer characteristics compared to conventionalfluids.Stefan blowing can further enhance the heat transfer capabilities of nano-fluids by increasing the massflux and turbulence at the surface.This can be beneficial in a wide range of applications,such as heat exchangers,electronic cooling,and solar energy devices.The convective boundary condition accounts for heat transfer effects,influencing temperature distribution and the thermal boundary layer.Depending on the direction of heat transfer,the convective boundary condition can induce cooling or heating effects on the inclined plate.This has practical implications for various engineering applications,such as the cooling of electronic devices or heating in industrial processes.Carreau nanofluids have a wide range of potential applications in heat transfer,energy storage,drug delivery,and food processing.This research investigates how the presence of Stefan blowing affects the properties of Carreau nanofluid flow across a convectively heated tilted plate.Heat and mass transport phenomena are studied using quadratic thermal radiation and chemical reaction parameters.The mathematical model for this work is based on the Buongiorno model.The governing equations are converted into a system of ordinary differential equations and then solved using the bvp4c solver.Physical parameters such as the mass transfer rate can be visualized using bar graphs.The study’s primary findings are that when the Weissenberg number increases,the velocity rises and the concentration profile declines due to Brownian motion.It is discovered that,when 0.5≤γ≤3(the inverse porosity parameter),the friction factor declines by 0.34001(in the presence of Stefan blowing),an展开更多
The present article explores the entropy generation of radiating viscoelastic second grade nanofluid in a porous channel confined between two parallel plates. The boundaries of the plates are maintained at distinct te...The present article explores the entropy generation of radiating viscoelastic second grade nanofluid in a porous channel confined between two parallel plates. The boundaries of the plates are maintained at distinct temperatures and concentrations while the fluid is being sucked and injected periodically through upper and lower plates. The buoyancy forces, thermophoresis and Brownian motion are also considered due to the temperature and concentration differences across the channel. The system of governing partial differential equations has been transferred into a system of ordinary differential equations(ODEs) by appropriate similarity relations, and a shooting method with the fourth-order Runge-Kutta scheme is used for the solutions. The results are analyzed in detail for dimensionless velocity components. The temperature, concentration distributions, the entropy generation number, and the Bejan number corresponding to various fluid and geometric parameters are shown graphically. The skin friction, heat and mass transfer rates are presented in the form of tables. It is noticed that the temperature profile of the fluid is enhanced with the Brownian motion, whereas the concentration profile of the fluid is decreased with the thermophoresis parameter, and the entropy and Bejan numbers exhibit the opposite trend for the suction and injection ratio.展开更多
This study presents a numerical model for the thermal-elastohydrodynamic lubrication of heterogeneous materials in impact motion,in which a rigid ball bounces on a starved non-Newtonian oil-covered plane surface of an...This study presents a numerical model for the thermal-elastohydrodynamic lubrication of heterogeneous materials in impact motion,in which a rigid ball bounces on a starved non-Newtonian oil-covered plane surface of an elastic semi-infinite heterogeneous solid with inhomogeneous inclusions.The impact–rebound process and the microscopic response of the subsurface inhomogeneous inclusions are investigated.The inclusions are homogenized according to Eshelby’s equivalent inclusion method.The Elrod algorithm is adopted to determine the lubrication starvation based on the solutions of pressure and film thickness,while the lubricant velocity and shear rate of the non-Newtonian lubricant are derived by using the separation flow method.The dynamic response of the cases subjected to constant impact mass,momentum,and energy is discussed to reveal the influence of the initial drop height on the impact–rebound process.The results imply that the inclusion disturbs the subsurface stress field and affects the dynamic response of the contact system when the surface pressure is high.The impact energy is the decisive factor for the stress peak,maximum hydrodynamic force,and restitution coefficient,while the dynamic response during the early approaching process is controlled by the drop height.展开更多
以全国大学生工程训练综合能力竞赛的竞赛命题为背景,系统地说明了符合比赛要求的热能小车的设计思路和步骤。主要对热能小车的非标零件进行设计并运用Soild Works完成三维制图并进行装配,最后使用Soild Works Motion对转向系统进行合...以全国大学生工程训练综合能力竞赛的竞赛命题为背景,系统地说明了符合比赛要求的热能小车的设计思路和步骤。主要对热能小车的非标零件进行设计并运用Soild Works完成三维制图并进行装配,最后使用Soild Works Motion对转向系统进行合理性分析,完成设计。展开更多
Low-energy,high-efficiency desalination techniques are important because of the critical water-energy nexus.In particular,membrane distillation has great potential to harness low-grade and renewable energy sources.Com...Low-energy,high-efficiency desalination techniques are important because of the critical water-energy nexus.In particular,membrane distillation has great potential to harness low-grade and renewable energy sources.Composite membranes using micro-and nanomaterials have new capabilities and characteristics.This review focuses on the most recent developments and potential capabilities in membrane distillation systems from the perspective of nanomaterial enhancements,thermal management,and water transport.Self-heating nanomaterial membrane distillations using permeable composite membranes with significant photothermal or Joule-heating conversion capabilities enable macroscale thermal management and mitigate temperature polarization effects.Modifying the membrane structure and its interaction with water can accelerate water transport and evaporation,improving distillation at the microscopic level.This is expected to provide directions for the fabrication and manipulation of novel micro-and nanocomposite membranes for distillation processes at various levels,and enhance their applications.展开更多
In 1985, Kroto, SmaUey and their co-workers discovered a series of new forms of elementary carbons in experiments: many carbon atoms gather together to form quite stable clusters in gas-phase, among which C<sub>...In 1985, Kroto, SmaUey and their co-workers discovered a series of new forms of elementary carbons in experiments: many carbon atoms gather together to form quite stable clusters in gas-phase, among which C<sub>60</sub> is of the greatest abundance. Since then, many experimental and theoretical scientists have paid more attention to C<sub>60</sub>. They found展开更多
Nanofluids were prepared by dispersing Cu nanoparticles （-20nm） in n-tetradecane by a two-step method. The effective thermal conductivity was measured for various nanoparticle volume fractions （0.0001-0.02） and te...Nanofluids were prepared by dispersing Cu nanoparticles （-20nm） in n-tetradecane by a two-step method. The effective thermal conductivity was measured for various nanoparticle volume fractions （0.0001-0.02） and temperatures （306.22-452.66 K）. The experimental data compares well with the Jang and Choi model, The thermal conductivity enhancement was lower above 391.06 K than for that between 306,22 and 360,77 K, The interfacial thermal resistance increased with increasing temperature, The effective thermal conductivity enhancement was greater than that obtained with a more viscous fluid as the base media at 452,66 K because of nanoconvection induced by nanoparticle Brownian motion at high temoerature.展开更多
基金supported by the Shandong Science and Technology Development Plan(No.GG201809230040)the National Natural Science Foundation of China(Grant Nos.61573202 and 11847135).
文摘A flexible,multi-site tactile and thermal sensor(MTTS)based on polyvinylidene fluoride(resolution 50×50)is reported.It can be used to implement spatial mapping caused by tactile and thermal events and record the two-dimensional motion trajectory of a tracked target object.The output voltage and current signal are recorded as amapping by sensing the external pressure and thermal radiation stimulus,and the response distribution is dynamically observed on the three-dimensional interface.Through the mapping relationship between the established piezoelectric and pyroelectric signals,the piezoelectric component and the pyroelectric component are effectively extracted from the composite signals.The MTTS has a good sensitivity for tactile and thermal detection,and the electrodes have good synchronism.In addition,the signal interference is less than 9.5%and decreases as the pressure decreases after the distance between adjacent sites exceeds 200μm.The integration of MTTS and signal processing units has potential applications in human-machine interaction systems,health status detection and smart assistive devices.
基金funding this research through Researchers Supporting Project number:RSPD2024R650,King Saud University,Riyadh,Saudi Arabia.
文摘Entropy analysis can help to identify the sources of entropy generation in a heat transfer process more accurately than other methods,such as energy efficiency analysis.This is because entropy analysis takes into account the quality of energy as well as its quantity.Na-nofluids have already been shown to have superior heat transfer characteristics compared to conventionalfluids.Stefan blowing can further enhance the heat transfer capabilities of nano-fluids by increasing the massflux and turbulence at the surface.This can be beneficial in a wide range of applications,such as heat exchangers,electronic cooling,and solar energy devices.The convective boundary condition accounts for heat transfer effects,influencing temperature distribution and the thermal boundary layer.Depending on the direction of heat transfer,the convective boundary condition can induce cooling or heating effects on the inclined plate.This has practical implications for various engineering applications,such as the cooling of electronic devices or heating in industrial processes.Carreau nanofluids have a wide range of potential applications in heat transfer,energy storage,drug delivery,and food processing.This research investigates how the presence of Stefan blowing affects the properties of Carreau nanofluid flow across a convectively heated tilted plate.Heat and mass transport phenomena are studied using quadratic thermal radiation and chemical reaction parameters.The mathematical model for this work is based on the Buongiorno model.The governing equations are converted into a system of ordinary differential equations and then solved using the bvp4c solver.Physical parameters such as the mass transfer rate can be visualized using bar graphs.The study’s primary findings are that when the Weissenberg number increases,the velocity rises and the concentration profile declines due to Brownian motion.It is discovered that,when 0.5≤γ≤3(the inverse porosity parameter),the friction factor declines by 0.34001(in the presence of Stefan blowing),an
基金supported by the Senior Research Fellowship of the Defence Research and Development Organization(No.DIAT/F/Acad(Ph.D.)/1613/15-52-12)
文摘The present article explores the entropy generation of radiating viscoelastic second grade nanofluid in a porous channel confined between two parallel plates. The boundaries of the plates are maintained at distinct temperatures and concentrations while the fluid is being sucked and injected periodically through upper and lower plates. The buoyancy forces, thermophoresis and Brownian motion are also considered due to the temperature and concentration differences across the channel. The system of governing partial differential equations has been transferred into a system of ordinary differential equations(ODEs) by appropriate similarity relations, and a shooting method with the fourth-order Runge-Kutta scheme is used for the solutions. The results are analyzed in detail for dimensionless velocity components. The temperature, concentration distributions, the entropy generation number, and the Bejan number corresponding to various fluid and geometric parameters are shown graphically. The skin friction, heat and mass transfer rates are presented in the form of tables. It is noticed that the temperature profile of the fluid is enhanced with the Brownian motion, whereas the concentration profile of the fluid is decreased with the thermophoresis parameter, and the entropy and Bejan numbers exhibit the opposite trend for the suction and injection ratio.
基金the National Research Foundation(NRF),Singapore,SMRT,Singapore and Nanyang Technological University,Singapore.Q.B.also acknowledges the support from National Natural Science Foundation of China,China(Grant No.51905051).
文摘This study presents a numerical model for the thermal-elastohydrodynamic lubrication of heterogeneous materials in impact motion,in which a rigid ball bounces on a starved non-Newtonian oil-covered plane surface of an elastic semi-infinite heterogeneous solid with inhomogeneous inclusions.The impact–rebound process and the microscopic response of the subsurface inhomogeneous inclusions are investigated.The inclusions are homogenized according to Eshelby’s equivalent inclusion method.The Elrod algorithm is adopted to determine the lubrication starvation based on the solutions of pressure and film thickness,while the lubricant velocity and shear rate of the non-Newtonian lubricant are derived by using the separation flow method.The dynamic response of the cases subjected to constant impact mass,momentum,and energy is discussed to reveal the influence of the initial drop height on the impact–rebound process.The results imply that the inclusion disturbs the subsurface stress field and affects the dynamic response of the contact system when the surface pressure is high.The impact energy is the decisive factor for the stress peak,maximum hydrodynamic force,and restitution coefficient,while the dynamic response during the early approaching process is controlled by the drop height.
基金supported by the Key Research and Development Program-Guidance Project of Heilongjiang Province of China(Grant No.GZ20210150)。
文摘Low-energy,high-efficiency desalination techniques are important because of the critical water-energy nexus.In particular,membrane distillation has great potential to harness low-grade and renewable energy sources.Composite membranes using micro-and nanomaterials have new capabilities and characteristics.This review focuses on the most recent developments and potential capabilities in membrane distillation systems from the perspective of nanomaterial enhancements,thermal management,and water transport.Self-heating nanomaterial membrane distillations using permeable composite membranes with significant photothermal or Joule-heating conversion capabilities enable macroscale thermal management and mitigate temperature polarization effects.Modifying the membrane structure and its interaction with water can accelerate water transport and evaporation,improving distillation at the microscopic level.This is expected to provide directions for the fabrication and manipulation of novel micro-and nanocomposite membranes for distillation processes at various levels,and enhance their applications.
基金Project supported by the National Natural Scienoe Foundation of China
文摘In 1985, Kroto, SmaUey and their co-workers discovered a series of new forms of elementary carbons in experiments: many carbon atoms gather together to form quite stable clusters in gas-phase, among which C<sub>60</sub> is of the greatest abundance. Since then, many experimental and theoretical scientists have paid more attention to C<sub>60</sub>. They found
基金support of the Doctoral Fund of the Ministry of Education of China(No.20110002110088)the Science Fund for Creative Research Groups(No.51321002)
文摘Nanofluids were prepared by dispersing Cu nanoparticles （-20nm） in n-tetradecane by a two-step method. The effective thermal conductivity was measured for various nanoparticle volume fractions （0.0001-0.02） and temperatures （306.22-452.66 K）. The experimental data compares well with the Jang and Choi model, The thermal conductivity enhancement was lower above 391.06 K than for that between 306,22 and 360,77 K, The interfacial thermal resistance increased with increasing temperature, The effective thermal conductivity enhancement was greater than that obtained with a more viscous fluid as the base media at 452,66 K because of nanoconvection induced by nanoparticle Brownian motion at high temoerature.
