The high thermal conductivity of the nanoparticles in hybrid nanofluids results in enhanced thermal conductivity associated with their base fluids.Enhanced heat transfer is a result of this high thermal conductivity,w...The high thermal conductivity of the nanoparticles in hybrid nanofluids results in enhanced thermal conductivity associated with their base fluids.Enhanced heat transfer is a result of this high thermal conductivity,which has significant applications in heat exchangers and engineering devices.To optimize heat transfer,a liquid film of Cu and TiO_(2)hybrid nanofluid behind a stretching sheet in a variable porous medium is being considered due to its importance.The nature of the fluid is considered time-dependent and the thickness of the liquid film is measured variable adjustable with the variable porous space and favorable for the uniform flow of the liquid film.The solution of the problem is acquired using the homotopy analysis method HAM,and the artificial neural network ANN is applied to obtain detailed information in the form of error estimation and validations using the fitting curve analysis.HAM data is utilized to train the ANN in this study,which uses Cu and TiO_(2)hybrid nanofluids in a variable porous space for unsteady thin film flow,and it is used to train the ANN.The results indicate that Cu and TiO_(2)play a greater role in boosting the rate.展开更多
A physical model of series of the conductivity on chain and the interchain conductivitybetween chains is proposed to explain enhanced conductivity of stretched conducting polymers.This model suggests that the enhanced...A physical model of series of the conductivity on chain and the interchain conductivitybetween chains is proposed to explain enhanced conductivity of stretched conducting polymers.This model suggests that the enhanced conductivity for stretched conducting polymers might bedue to increasing of the interchain conductivity between chains along the elongation direction afterdrawing processes if the conductivity on chain is assumed much larger than that of the interchainconductivity between chains. According to this model, it is expected that the temperaturedependence of conductivity measured by four-probe method for stretched conducting polymers iscontrolled by a variation of the interchain conductivity between chains with temperature, whichcan be used to explain that a metallic temperature dependence of conductivity for stretchedconducting polymers is not observed although the conductivity along the elongation direction isenhanced by two or three orders of magnitude.展开更多
To study vertical sag requirements and factors affecting the stretched wire alignment method,the vertical sag equation is first derived theoretically.Subsequently,the influencing factors(such as the hanging weight or ...To study vertical sag requirements and factors affecting the stretched wire alignment method,the vertical sag equation is first derived theoretically.Subsequently,the influencing factors(such as the hanging weight or tension,span length,temperature change,elastic deformation,and the Earth’s rotation)of the vertical sag are summarized,and their validity is verified through actual measurements.Finally,the essential factors affecting vertical sag,i.e.,the specific strength and length,are discussed.It is believed that the vertical sag of a stretched wire is proportional to the square of the length and inversely proportional to the specific strength of the material.展开更多
Cold-stretched pressure vessels from austenitic stainless steels （ASS） are widely used for storage and transportation of liquefied gases, and have such advantages as thin wall and light weight. Fatigue is an importa...Cold-stretched pressure vessels from austenitic stainless steels （ASS） are widely used for storage and transportation of liquefied gases, and have such advantages as thin wall and light weight. Fatigue is an important concern in these pressure vessels, which are subjected to alternative loads. Even though several codes and standards have guidelines on these pressure vessels, there are no relevant design methods on fatigue failure. To understand the fatigue properties of ASS 1.4301 （equivalents include UNS $30400 and AISI 304） in solution-annealed （SA） and cold-stretched conditions （9% strain level） and the response of fatigue properties to cold stretching （CS）, low-cycle fatigue （LCF） tests were performed at room temperature, with total strain amplitudes ranging from ：~0.4% to ＂0.8%. Martensite transformations were measured during the tests. Comparisons on cyclic stress response, cyclic stress-strain behavior, and fatigue life were carried out between SA and CS materials. Results show that CS reduces the initial hardening stage, but prolongs the softening period in the cyclic stress response. Martensite transformation helps form a stable regime and subsequent secondary hardening. The stresses of monotonic and cyclic stress-strain curves are improved by CS, which leads to a lower plastic strain and a much higher elastic strain. The fatigue resistance of the CS material is better than that of the SA material, which is approximately 1 - 103 to 2 - 104 cycles. The S-N curve of the ASME standard for ASS is compared with the fatigue data and is justified to be suitable for the fatigue design of cold-stretched pressure vessels. However, considering the CS material has a better fatigue resistance, the S-N curve will be more conservative. The present study would be helpful in making full use of the advantages of CS to develop a new S-N curve for fatigue design of cold-stretched pressure vessels.展开更多
Based on the rigid-plastic theory, using a coupled thermomechanical model, the stretching process of a circular section billet is simulated by means of FEM software Deform-2D. Through the distribution of internal stre...Based on the rigid-plastic theory, using a coupled thermomechanical model, the stretching process of a circular section billet is simulated by means of FEM software Deform-2D. Through the distribution of internal stress fields of stretched round billet, it is found that the shear stress field is the main factor to induce Mannesmann＇s effect. The simulation results show that a reasonable distribution of the temperature field may improve the internal quality of the circular section billet in the stretching process.展开更多
Recovery behavior of uniaxially stretched amorphous poly(ethylene terephthalate)(a-PET)film near glass transition temperature(T-g)was studied.A strain recovery curve showed that the recovery was made up of two compone...Recovery behavior of uniaxially stretched amorphous poly(ethylene terephthalate)(a-PET)film near glass transition temperature(T-g)was studied.A strain recovery curve showed that the recovery was made up of two components each with different relaxation time.展开更多
It is believed that mechanical stimuli, such as stretching of the extracellular matrix, are transmitted into cells via focal adhesion complexes and the actin cytoskeleton. Transmission dynamics of strain from the extr...It is believed that mechanical stimuli, such as stretching of the extracellular matrix, are transmitted into cells via focal adhesion complexes and the actin cytoskeleton. Transmission dynamics of strain from the extracellular matrix into intracellular organelles is crucial to clarify the mechanosensing mechanisms of cells. In this study, we observed deformation behavior of actin stress fibers under uniaxial stretch using an originally developed cell-stretching microelectromechanical system (MEMS) device. It was difficult to conduct in situ observation of cells under stretch using conventional cell stretching devices, because motion artifacts such as rigid displacement during stretch application were not negligible. Our novel cell-stretching MEMS device suppressed rigid displacement while stretching, and we succeeded in obtaining time-lapse images of stretched cells. Uniaxial strain with a 10% magnitude and strain rate of 0.5%/sec was applied to cells. Deformation behaviors of the cells and actin stress fibers were recorded using a confocal laser scanning microscope. In time-lapse images of stretched cells, strains along each stress fiber were measured manually. As a result, in cells with a relatively homogeneous stress fiber structure oriented in one direction, distribution of the axial strain on stress fibers generally corresponded to deformation of the stretching sheet on which the cells had adhered. However, in cells with a heterogeneous stress fiber structure oriented in several directions, we found that the strain distribution along stress fibers was not homogeneous. In regions around the cell nucleus, there was a more complicated strain distribution compared with other regions. Our results suggest the cell nucleus with a stiff mechanical resistance yields such a complicated strain distribution in stress fibers.展开更多
An experimental study investigated the characteristics of a stretched cylindrical diffusion flame, with a convex curvature with respect to the air stream, in response to periodic air flow velocity oscillation. The fue...An experimental study investigated the characteristics of a stretched cylindrical diffusion flame, with a convex curvature with respect to the air stream, in response to periodic air flow velocity oscillation. The fuel was methane diluted with nitrogen, and the oxidizer air. The oscillation frequency was varied from 5 to 250 Hz. The results are summarized as follows. Though the fluctuation amplitude of the air stream velocity gradient was constant with respect to the frequency, the amplitude of the fuel stream increased. The fluctuation amplitude of the flame radius changed quasi-steadily from 5 to 25 Hz, and decreased with increasing frequency in the frequency range greater than 50 Hz. The flame luminosity did not respond quasi-steadily at 5 Hz, and the oscillation amplitude of flame luminosity was less than that of a steady flame, over the same velocity fluctuation range. The oscillation amplitude of luminosity peaked at 50 Hz, and was greater than that of a steady flame. It is considered that this complex change in flame luminosity with respect to frequency was closely related to the phase difference in the respective time variations in the ratio of flame thickness to radius, the velocity gradients of the air and fuel streams, and the magnitude of these values, with the ratio of flame thickness to radius related to the flame curvature effect, the velocity gradient of the air stream correlated to the flame stretch effect, and the velocity gradient of the fuel stream impacting the fuel transportation.展开更多
A review of the literature revealed that nanofluids are more effective in transferring heat than conventional fluids.Since there are significant gaps in the illumination of existing methods for enhancing heat transmis...A review of the literature revealed that nanofluids are more effective in transferring heat than conventional fluids.Since there are significant gaps in the illumination of existing methods for enhancing heat transmission in nanomaterials,a thorough investigation of the previously outlined models is essential.The goal of the ongoing study is to determine whether the microscopic gold particles that are involved in mass and heat transmission drift in freely.The current study examines heat and mass transfer on 3D MHD Darcy–Forchheimer flow of Casson nanofluid-induced bio-convection past a stretched sheet.The inclusion of the nanoparticles is a result of their peculiar properties,such as remarkable thermal conductivity,which are important in heat exchangers and cutting-edge nanotechnology.The gyrotactic microorganisms must be included to prevent the potential deposition of minute particles.The proposed flow dynamics model consists of an evolving nonlinear system of PDEs,which is subsequently reduced to a system of dimensionless ODEs utilizing similarity approximations.MATLAB software was utilized to create an effective code for the Runge-Kutta technique using a shooting tool to acquire numerical results.This method is extensively used to solve these issues since it is accurate to fourth order,efficient,and affordable.The influence of submerged factors on the velocity,temperature,concentration,and density of motile microorganisms is shown in the figures.Additionally,tables and bar charts are used to illustrate the physical characteristics of the Nusselt and Sherwood numbers for the densities of both nanoparticles and motile microorganisms.The dimensionless velocities are observed declining when the casson,magnetic,porosity,and forchheimer parameters grow,whereas the dimensionless temperature and concentration rise as the thermophoresis parameter rises.This work provides insights into practical applications such nanofluidic,energy conservation,friction reduction,and power generation.Furthermore,in a concentration field,the Brownian and thermophoresis parameters exhibit very distinct behaviours.However,the work makes a significant point that the flow of a Casson fluid including nanoparticles can be regulated by appropriately modifying the Casson parameter,thermophoresis parameter,and Brownian motion parameter.展开更多
The objective of this work is to examine how temperature-dependent thermal conductivity and concentration-dependent molecular diffusion affect Reiner-Philippoff nanofluid flow past a nonlinear stretching sheet. At the...The objective of this work is to examine how temperature-dependent thermal conductivity and concentration-dependent molecular diffusion affect Reiner-Philippoff nanofluid flow past a nonlinear stretching sheet. At the interface of the elongated surface zero-mass flux and melting heat condition are incorporated. The formulated mathematical problem is simplified by implementing suitable similarity transformations. For the numerical solution bvp4c is utilized. The parameters emerging in the model are discussed versus allied profiles through graphical illustrations. It is perceived that the velocity of the fluid decays on incrementing the Bingham number. The gyrotactic microorganism profile declines on amplifying the Peclet number. The validation of the proposed model is also added to this study. .展开更多
A new stretched-wire system is built for a cryogenic permanent magnet undulator in High Energy Photon Source Testing Facility.The system has two functions:integral field measurement and magnet gap measurement.Integral...A new stretched-wire system is built for a cryogenic permanent magnet undulator in High Energy Photon Source Testing Facility.The system has two functions:integral field measurement and magnet gap measurement.Integral field measurement and gap measurement are important for evaluation and optimization of the magnetic performance of the undulator in cryogenic-vacuum environment.Two high-precision,high-load motion stages are used for accurate positioning.A special fix structure of stretched wire is adopted for vacuum environment.To reduce the deflection of the 3-meter-long wire,constant tension is maintained along the wire.The measurement repeatability of field integral and magnetic gap is the key performance which depends on the stability of wire and suppression of the electric noise.Strategy of improving the measurement accuracy and stability is presented.展开更多
[Background]High harmonic cavities are widely used in electron storage rings to lengthen thebunch,lower the bunch peak current,thereby reducing the IBS effect,enhancing the Touschek lifetime,as well asproviding Landau...[Background]High harmonic cavities are widely used in electron storage rings to lengthen thebunch,lower the bunch peak current,thereby reducing the IBS effect,enhancing the Touschek lifetime,as well asproviding Landau damping,which is particularly important for storage rings operating with ultra-low emittance or atlow beam energy.[Purpose]To further increase the bunch length without additional hardware costs,the phasemodulation in a dual-RF system is considered.[Methods]In this paper,turn-by-turn simulations incorporating randomsynchrotron radiation excitation are conducted,and a brief analysis is presented to explain the bunch lengtheningmechanism.[Results]Simulation results reveal that the peak current can be further reduced,thereby mitigating IBSeffects and enhancing the Touschek lifetime.Although the energy spread increases,which tends to reduce thebrightness of higher-harmonic radiation from the undulator,the brightness of the fundamental harmonic can,in fact,beimproved.展开更多
Spectra and angular distributions strongly populated by 56Fe(a, d)58Co reaction at HI-13 Tandem accelerator using AE-E telescope system and Q3D magnetic spectrometer have been measured and analyzed with microscopic DW...Spectra and angular distributions strongly populated by 56Fe(a, d)58Co reaction at HI-13 Tandem accelerator using AE-E telescope system and Q3D magnetic spectrometer have been measured and analyzed with microscopic DWBA. The 6.79MeV state of 58Co was identified as stretched state with the ) configuration which has the highest coupled angular momentum 9+ so far observed. Evidence for 6.4MeV high excitation level on the anomalous enhancement in the cross section, with p-n pair coupled to the minimum allowed angular momentum was discussed. The level was first assigned to an unnatural parity state with F=l+ in 58Co.展开更多
The purpose of the present investigation is to explore the implications of Cross fluid in a Darcy-Forchheimer porousmediumdue to the tri-hybrid nanofluid past a porous cylinder.Thermal radiation,heat generation,therma...The purpose of the present investigation is to explore the implications of Cross fluid in a Darcy-Forchheimer porousmediumdue to the tri-hybrid nanofluid past a porous cylinder.Thermal radiation,heat generation,thermal convection,solutal convective and chemical reaction have been encountered in this analysis.Entropy generation has been accounted for under the fluidic friction,heat rate analysis,and porosity analysis.Three different nanoparticles of multiwall carbon nanotube(MWCNT),aluminum oxide(Al_(2)O_(3)),and silver(Ag)are utilized to illustrate the tri-hybrid nanofluid flow with Ethlene Glycol(EG)as the base fluid.The governance model,consisting of linked inadequate differential conditions,is transformed into an ordinary configuration of nonlinear coupled differential conditions by acceptable adjustments.The obtained outcomes in combination with the bvp4c approach are then used to resolve the generated ODEs.For discussion purposes,the impacts of the physical limitations on temperature profile,velocity,and concentration have also been illustrated.Numerical results have been obtained for the diffusion rate,heat transfer rate,drag force,and other factors.While the Forchheimer parameter and the inclination angle reduce the fluid flow’s velocity,the Biot number of heat and mass transfer influences the fluid’s temperature.According to the findings,hybrid nanofluid is the most effective way to improve heat transmission and may also be utilized for cooling.Three different kinds of nanofluids were used in a comparative examination to clarify the study’s conclusions.Changes in viscosity and porousness caused the nanofluids’velocity to drop by 13.12%and 15.8%,respectively;however,trihybrid nanofluids with improved convection showed a 13.12%rise.展开更多
The flow of a tetra-hybrid Casson nanofluid(Al_(2)O_(3)-CuO-TiO_(2)-Ag/H_(2)O)over a nonlinear stretching sheet is investigated.The Buongiorno model is used to account for thermophoresis and Brownian motion,while ther...The flow of a tetra-hybrid Casson nanofluid(Al_(2)O_(3)-CuO-TiO_(2)-Ag/H_(2)O)over a nonlinear stretching sheet is investigated.The Buongiorno model is used to account for thermophoresis and Brownian motion,while thermal radiation is incorporated to examine its influence on the thermal boundary layer.The governing partial differential equations(PDEs)are reduced to a system of nonlinear ordinary differential equations(ODEs)with fully non-dimensional similarity transformations involving all independent variables.To solve the obtained highly nonlinear system of differential equations,a novel Clique polynomial collocation method is applied.The analysis focuses on the effects of the Casson parameter,power index,radiation parameter,thermophoresis parameter,Brownian motion parameter,and Lewis number.The key findings show that thermal radiation intensifies the thermal boundary layer,the Casson parameter reduces the velocity,and the Lewis number suppresses the concentration with direct relevance to polymer processing,coating flows,electronic cooling,and biomedical applications.展开更多
The water-quenched(WQ)2195 Al−Li alloy was subjected to stretching at different temperatures,from room temperature(RT)to−196℃(CT),to investigate the effect of cryogenic deformation on the aging precipitation behavior...The water-quenched(WQ)2195 Al−Li alloy was subjected to stretching at different temperatures,from room temperature(RT)to−196℃(CT),to investigate the effect of cryogenic deformation on the aging precipitation behaviors and mechanical properties.The precipitation kinetics of the T1 phase and the microstructures in peak aging state were investigated through the differential scanning calorimetric(DSC)tests and electron microscopy observation.The results show that−196℃deformation produces a high dislocation density,which promotes the precipitation of the T1 phase and refines its sizes significantly.In addition,the grain boundary precipitates(GBPs)of−196℃-stretched samples are suppressed considerably due to the high dislocation density in the grain interiors,which increases the ductility.In comparison,the strength remains nearly constant.Thus,it is indicated that cryogenic forming has the potential to provide the shape and property control for the manufacture of critical components of aluminum alloys.展开更多
The paper is the continuation of the previous article in which the stretched field method on is developed to solve the equations for grossly determiners. The first degree result is the same as the Lundgren’s small pa...The paper is the continuation of the previous article in which the stretched field method on is developed to solve the equations for grossly determiners. The first degree result is the same as the Lundgren’s small parameter expansion展开更多
Magnetic nanofiuid hydrothermal analysis over a plate is studied that includes consideration of thermal radiation. The Runge-Kutta （RK4） method is utilized to get solution of ODEs which are obtained from similarity ...Magnetic nanofiuid hydrothermal analysis over a plate is studied that includes consideration of thermal radiation. The Runge-Kutta （RK4） method is utilized to get solution of ODEs which are obtained from similarity solution. In considering the impacts of Brownian motion, we applied Koo-Kleinstreuer-Li cor- relation to simulate the properties of CuO-water. The influence is discussed of important parameters such as the temperature index, magnetic, radiation, and velocity ratio parameters and volume fraction of nanoparticle on hydrothermal behavior. Results illustrate that the coefficient of skin friction enhances with enhancing magnetic parameter while reduces with enhancing velocity ratio parameter. Also the Nusselt number was found to directly depend on the velocity ratio and temperature index parameters but has an inverse dependence on the magnetic and radiation parameters.展开更多
The current work is being done to investigate the flow of nanofluids across a porous exponential stretching surface in the presence of a heat source/sink,thermophoretic particle deposition,and bioconvection.The collec...The current work is being done to investigate the flow of nanofluids across a porous exponential stretching surface in the presence of a heat source/sink,thermophoretic particle deposition,and bioconvection.The collection of PDEs(partial differential equations)that represent the fluid moment is converted to a system of ODEs(ordinary differential equations)with the use of suitable similarity variables,and these equations are then numerically solved using Runge Kutta Fehlberg and the shooting approach.For different physical limitations,the numerical results are visually represented.The results show that increasing the porosity characteristics reduces velocity.The mass transfer decreases as the thermophoretic limitation increases.Increases in the porosity parameter reduce skin friction,increases in the solid volume fraction improve the rate of thermal distribution,and increases in the thermophoretic parameter increase the rate of mass transfer.展开更多
A novel algorithm,STRETCHEDNMF,is introduced for non-negative matrix factorization(NMF),accounting for signal stretching along the independent variable’s axis.It addresses signal variability caused by stretching,prov...A novel algorithm,STRETCHEDNMF,is introduced for non-negative matrix factorization(NMF),accounting for signal stretching along the independent variable’s axis.It addresses signal variability caused by stretching,proving beneficial for analyzing data such as powder diffraction at varying temperatures.This approach provides a more meaningful decomposition,particularly when the component signals resemble those from chemical components in the sample.The STRETCHEDNMF model introduces a stretching factor to accommodate signal expansion,solved using discretization and Block Coordinate Descent algorithms.Initial experimental results indicate that the STRETCHEDNMF model outperforms conventional NMF for datasets exhibiting such expansion.An enhanced version,SPARSE-STRETCHEDNMF,optimized for powder diffraction data from crystalline materials,leverages signal sparsity for accurate extraction,especially with small stretches.Experimental results showcase its effectiveness in analyzing diffraction data,including success in real-time chemical reaction experiments.展开更多
文摘The high thermal conductivity of the nanoparticles in hybrid nanofluids results in enhanced thermal conductivity associated with their base fluids.Enhanced heat transfer is a result of this high thermal conductivity,which has significant applications in heat exchangers and engineering devices.To optimize heat transfer,a liquid film of Cu and TiO_(2)hybrid nanofluid behind a stretching sheet in a variable porous medium is being considered due to its importance.The nature of the fluid is considered time-dependent and the thickness of the liquid film is measured variable adjustable with the variable porous space and favorable for the uniform flow of the liquid film.The solution of the problem is acquired using the homotopy analysis method HAM,and the artificial neural network ANN is applied to obtain detailed information in the form of error estimation and validations using the fitting curve analysis.HAM data is utilized to train the ANN in this study,which uses Cu and TiO_(2)hybrid nanofluids in a variable porous space for unsteady thin film flow,and it is used to train the ANN.The results indicate that Cu and TiO_(2)play a greater role in boosting the rate.
基金This work was supported by the National Natural Science Foundation of China and the Chinese Academy of Sciences.
文摘A physical model of series of the conductivity on chain and the interchain conductivitybetween chains is proposed to explain enhanced conductivity of stretched conducting polymers.This model suggests that the enhanced conductivity for stretched conducting polymers might bedue to increasing of the interchain conductivity between chains along the elongation direction afterdrawing processes if the conductivity on chain is assumed much larger than that of the interchainconductivity between chains. According to this model, it is expected that the temperaturedependence of conductivity measured by four-probe method for stretched conducting polymers iscontrolled by a variation of the interchain conductivity between chains with temperature, whichcan be used to explain that a metallic temperature dependence of conductivity for stretchedconducting polymers is not observed although the conductivity along the elongation direction isenhanced by two or three orders of magnitude.
基金Large Research Infrastructures“China initiative Accelerator Driven System”(No.2017-000052-75-01-000590).
文摘To study vertical sag requirements and factors affecting the stretched wire alignment method,the vertical sag equation is first derived theoretically.Subsequently,the influencing factors(such as the hanging weight or tension,span length,temperature change,elastic deformation,and the Earth’s rotation)of the vertical sag are summarized,and their validity is verified through actual measurements.Finally,the essential factors affecting vertical sag,i.e.,the specific strength and length,are discussed.It is believed that the vertical sag of a stretched wire is proportional to the square of the length and inversely proportional to the specific strength of the material.
基金Project supported by the National Key Technology R&D Program (No.2011BAK06B0205)the International Science and Technology Cooperation Project (No. 2010DFB42960)the Key Technology Innovation Team of Zhejiang Province (No. 2010R50001),China
文摘Cold-stretched pressure vessels from austenitic stainless steels （ASS） are widely used for storage and transportation of liquefied gases, and have such advantages as thin wall and light weight. Fatigue is an important concern in these pressure vessels, which are subjected to alternative loads. Even though several codes and standards have guidelines on these pressure vessels, there are no relevant design methods on fatigue failure. To understand the fatigue properties of ASS 1.4301 （equivalents include UNS $30400 and AISI 304） in solution-annealed （SA） and cold-stretched conditions （9% strain level） and the response of fatigue properties to cold stretching （CS）, low-cycle fatigue （LCF） tests were performed at room temperature, with total strain amplitudes ranging from ：~0.4% to ＂0.8%. Martensite transformations were measured during the tests. Comparisons on cyclic stress response, cyclic stress-strain behavior, and fatigue life were carried out between SA and CS materials. Results show that CS reduces the initial hardening stage, but prolongs the softening period in the cyclic stress response. Martensite transformation helps form a stable regime and subsequent secondary hardening. The stresses of monotonic and cyclic stress-strain curves are improved by CS, which leads to a lower plastic strain and a much higher elastic strain. The fatigue resistance of the CS material is better than that of the SA material, which is approximately 1 - 103 to 2 - 104 cycles. The S-N curve of the ASME standard for ASS is compared with the fatigue data and is justified to be suitable for the fatigue design of cold-stretched pressure vessels. However, considering the CS material has a better fatigue resistance, the S-N curve will be more conservative. The present study would be helpful in making full use of the advantages of CS to develop a new S-N curve for fatigue design of cold-stretched pressure vessels.
基金Item Sponsored by National Natural Science Foundation of China(50475081)
文摘Based on the rigid-plastic theory, using a coupled thermomechanical model, the stretching process of a circular section billet is simulated by means of FEM software Deform-2D. Through the distribution of internal stress fields of stretched round billet, it is found that the shear stress field is the main factor to induce Mannesmann＇s effect. The simulation results show that a reasonable distribution of the temperature field may improve the internal quality of the circular section billet in the stretching process.
基金supported by the National Research Project-Macromolecular CondensedState.
文摘Recovery behavior of uniaxially stretched amorphous poly(ethylene terephthalate)(a-PET)film near glass transition temperature(T-g)was studied.A strain recovery curve showed that the recovery was made up of two components each with different relaxation time.
文摘It is believed that mechanical stimuli, such as stretching of the extracellular matrix, are transmitted into cells via focal adhesion complexes and the actin cytoskeleton. Transmission dynamics of strain from the extracellular matrix into intracellular organelles is crucial to clarify the mechanosensing mechanisms of cells. In this study, we observed deformation behavior of actin stress fibers under uniaxial stretch using an originally developed cell-stretching microelectromechanical system (MEMS) device. It was difficult to conduct in situ observation of cells under stretch using conventional cell stretching devices, because motion artifacts such as rigid displacement during stretch application were not negligible. Our novel cell-stretching MEMS device suppressed rigid displacement while stretching, and we succeeded in obtaining time-lapse images of stretched cells. Uniaxial strain with a 10% magnitude and strain rate of 0.5%/sec was applied to cells. Deformation behaviors of the cells and actin stress fibers were recorded using a confocal laser scanning microscope. In time-lapse images of stretched cells, strains along each stress fiber were measured manually. As a result, in cells with a relatively homogeneous stress fiber structure oriented in one direction, distribution of the axial strain on stress fibers generally corresponded to deformation of the stretching sheet on which the cells had adhered. However, in cells with a heterogeneous stress fiber structure oriented in several directions, we found that the strain distribution along stress fibers was not homogeneous. In regions around the cell nucleus, there was a more complicated strain distribution compared with other regions. Our results suggest the cell nucleus with a stiff mechanical resistance yields such a complicated strain distribution in stress fibers.
文摘An experimental study investigated the characteristics of a stretched cylindrical diffusion flame, with a convex curvature with respect to the air stream, in response to periodic air flow velocity oscillation. The fuel was methane diluted with nitrogen, and the oxidizer air. The oscillation frequency was varied from 5 to 250 Hz. The results are summarized as follows. Though the fluctuation amplitude of the air stream velocity gradient was constant with respect to the frequency, the amplitude of the fuel stream increased. The fluctuation amplitude of the flame radius changed quasi-steadily from 5 to 25 Hz, and decreased with increasing frequency in the frequency range greater than 50 Hz. The flame luminosity did not respond quasi-steadily at 5 Hz, and the oscillation amplitude of flame luminosity was less than that of a steady flame, over the same velocity fluctuation range. The oscillation amplitude of luminosity peaked at 50 Hz, and was greater than that of a steady flame. It is considered that this complex change in flame luminosity with respect to frequency was closely related to the phase difference in the respective time variations in the ratio of flame thickness to radius, the velocity gradients of the air and fuel streams, and the magnitude of these values, with the ratio of flame thickness to radius related to the flame curvature effect, the velocity gradient of the air stream correlated to the flame stretch effect, and the velocity gradient of the fuel stream impacting the fuel transportation.
文摘A review of the literature revealed that nanofluids are more effective in transferring heat than conventional fluids.Since there are significant gaps in the illumination of existing methods for enhancing heat transmission in nanomaterials,a thorough investigation of the previously outlined models is essential.The goal of the ongoing study is to determine whether the microscopic gold particles that are involved in mass and heat transmission drift in freely.The current study examines heat and mass transfer on 3D MHD Darcy–Forchheimer flow of Casson nanofluid-induced bio-convection past a stretched sheet.The inclusion of the nanoparticles is a result of their peculiar properties,such as remarkable thermal conductivity,which are important in heat exchangers and cutting-edge nanotechnology.The gyrotactic microorganisms must be included to prevent the potential deposition of minute particles.The proposed flow dynamics model consists of an evolving nonlinear system of PDEs,which is subsequently reduced to a system of dimensionless ODEs utilizing similarity approximations.MATLAB software was utilized to create an effective code for the Runge-Kutta technique using a shooting tool to acquire numerical results.This method is extensively used to solve these issues since it is accurate to fourth order,efficient,and affordable.The influence of submerged factors on the velocity,temperature,concentration,and density of motile microorganisms is shown in the figures.Additionally,tables and bar charts are used to illustrate the physical characteristics of the Nusselt and Sherwood numbers for the densities of both nanoparticles and motile microorganisms.The dimensionless velocities are observed declining when the casson,magnetic,porosity,and forchheimer parameters grow,whereas the dimensionless temperature and concentration rise as the thermophoresis parameter rises.This work provides insights into practical applications such nanofluidic,energy conservation,friction reduction,and power generation.Furthermore,in a concentration field,the Brownian and thermophoresis parameters exhibit very distinct behaviours.However,the work makes a significant point that the flow of a Casson fluid including nanoparticles can be regulated by appropriately modifying the Casson parameter,thermophoresis parameter,and Brownian motion parameter.
文摘The objective of this work is to examine how temperature-dependent thermal conductivity and concentration-dependent molecular diffusion affect Reiner-Philippoff nanofluid flow past a nonlinear stretching sheet. At the interface of the elongated surface zero-mass flux and melting heat condition are incorporated. The formulated mathematical problem is simplified by implementing suitable similarity transformations. For the numerical solution bvp4c is utilized. The parameters emerging in the model are discussed versus allied profiles through graphical illustrations. It is perceived that the velocity of the fluid decays on incrementing the Bingham number. The gyrotactic microorganism profile declines on amplifying the Peclet number. The validation of the proposed model is also added to this study. .
文摘A new stretched-wire system is built for a cryogenic permanent magnet undulator in High Energy Photon Source Testing Facility.The system has two functions:integral field measurement and magnet gap measurement.Integral field measurement and gap measurement are important for evaluation and optimization of the magnetic performance of the undulator in cryogenic-vacuum environment.Two high-precision,high-load motion stages are used for accurate positioning.A special fix structure of stretched wire is adopted for vacuum environment.To reduce the deflection of the 3-meter-long wire,constant tension is maintained along the wire.The measurement repeatability of field integral and magnetic gap is the key performance which depends on the stability of wire and suppression of the electric noise.Strategy of improving the measurement accuracy and stability is presented.
基金National Natural Science Foundation of China(12405168)The Fundamental Research Funds for the Central Universities,China(2024CDJXY004)。
文摘[Background]High harmonic cavities are widely used in electron storage rings to lengthen thebunch,lower the bunch peak current,thereby reducing the IBS effect,enhancing the Touschek lifetime,as well asproviding Landau damping,which is particularly important for storage rings operating with ultra-low emittance or atlow beam energy.[Purpose]To further increase the bunch length without additional hardware costs,the phasemodulation in a dual-RF system is considered.[Methods]In this paper,turn-by-turn simulations incorporating randomsynchrotron radiation excitation are conducted,and a brief analysis is presented to explain the bunch lengtheningmechanism.[Results]Simulation results reveal that the peak current can be further reduced,thereby mitigating IBSeffects and enhancing the Touschek lifetime.Although the energy spread increases,which tends to reduce thebrightness of higher-harmonic radiation from the undulator,the brightness of the fundamental harmonic can,in fact,beimproved.
基金National Natural Science Foundation of ChinaChina National Nuclear Corporation
文摘Spectra and angular distributions strongly populated by 56Fe(a, d)58Co reaction at HI-13 Tandem accelerator using AE-E telescope system and Q3D magnetic spectrometer have been measured and analyzed with microscopic DWBA. The 6.79MeV state of 58Co was identified as stretched state with the ) configuration which has the highest coupled angular momentum 9+ so far observed. Evidence for 6.4MeV high excitation level on the anomalous enhancement in the cross section, with p-n pair coupled to the minimum allowed angular momentum was discussed. The level was first assigned to an unnatural parity state with F=l+ in 58Co.
基金the research support through grants ANTARABANGSA(IRMG)-TEL-U/2025/FTKM/A00086.
文摘The purpose of the present investigation is to explore the implications of Cross fluid in a Darcy-Forchheimer porousmediumdue to the tri-hybrid nanofluid past a porous cylinder.Thermal radiation,heat generation,thermal convection,solutal convective and chemical reaction have been encountered in this analysis.Entropy generation has been accounted for under the fluidic friction,heat rate analysis,and porosity analysis.Three different nanoparticles of multiwall carbon nanotube(MWCNT),aluminum oxide(Al_(2)O_(3)),and silver(Ag)are utilized to illustrate the tri-hybrid nanofluid flow with Ethlene Glycol(EG)as the base fluid.The governance model,consisting of linked inadequate differential conditions,is transformed into an ordinary configuration of nonlinear coupled differential conditions by acceptable adjustments.The obtained outcomes in combination with the bvp4c approach are then used to resolve the generated ODEs.For discussion purposes,the impacts of the physical limitations on temperature profile,velocity,and concentration have also been illustrated.Numerical results have been obtained for the diffusion rate,heat transfer rate,drag force,and other factors.While the Forchheimer parameter and the inclination angle reduce the fluid flow’s velocity,the Biot number of heat and mass transfer influences the fluid’s temperature.According to the findings,hybrid nanofluid is the most effective way to improve heat transmission and may also be utilized for cooling.Three different kinds of nanofluids were used in a comparative examination to clarify the study’s conclusions.Changes in viscosity and porousness caused the nanofluids’velocity to drop by 13.12%and 15.8%,respectively;however,trihybrid nanofluids with improved convection showed a 13.12%rise.
基金the UGC,New Delhi,India for financial assistance via the UGC-Junior Research Fellowship(CSIR-UGC NET JULY 2024)(Student ID:241610090610)。
文摘The flow of a tetra-hybrid Casson nanofluid(Al_(2)O_(3)-CuO-TiO_(2)-Ag/H_(2)O)over a nonlinear stretching sheet is investigated.The Buongiorno model is used to account for thermophoresis and Brownian motion,while thermal radiation is incorporated to examine its influence on the thermal boundary layer.The governing partial differential equations(PDEs)are reduced to a system of nonlinear ordinary differential equations(ODEs)with fully non-dimensional similarity transformations involving all independent variables.To solve the obtained highly nonlinear system of differential equations,a novel Clique polynomial collocation method is applied.The analysis focuses on the effects of the Casson parameter,power index,radiation parameter,thermophoresis parameter,Brownian motion parameter,and Lewis number.The key findings show that thermal radiation intensifies the thermal boundary layer,the Casson parameter reduces the velocity,and the Lewis number suppresses the concentration with direct relevance to polymer processing,coating flows,electronic cooling,and biomedical applications.
基金financially supported by the National Key Research and Development Program of China (No. 2019YFA0708801)the National Natural Science Foundation of China (No. 51875125)。
文摘The water-quenched(WQ)2195 Al−Li alloy was subjected to stretching at different temperatures,from room temperature(RT)to−196℃(CT),to investigate the effect of cryogenic deformation on the aging precipitation behaviors and mechanical properties.The precipitation kinetics of the T1 phase and the microstructures in peak aging state were investigated through the differential scanning calorimetric(DSC)tests and electron microscopy observation.The results show that−196℃deformation produces a high dislocation density,which promotes the precipitation of the T1 phase and refines its sizes significantly.In addition,the grain boundary precipitates(GBPs)of−196℃-stretched samples are suppressed considerably due to the high dislocation density in the grain interiors,which increases the ductility.In comparison,the strength remains nearly constant.Thus,it is indicated that cryogenic forming has the potential to provide the shape and property control for the manufacture of critical components of aluminum alloys.
文摘The paper is the continuation of the previous article in which the stretched field method on is developed to solve the equations for grossly determiners. The first degree result is the same as the Lundgren’s small parameter expansion
文摘Magnetic nanofiuid hydrothermal analysis over a plate is studied that includes consideration of thermal radiation. The Runge-Kutta （RK4） method is utilized to get solution of ODEs which are obtained from similarity solution. In considering the impacts of Brownian motion, we applied Koo-Kleinstreuer-Li cor- relation to simulate the properties of CuO-water. The influence is discussed of important parameters such as the temperature index, magnetic, radiation, and velocity ratio parameters and volume fraction of nanoparticle on hydrothermal behavior. Results illustrate that the coefficient of skin friction enhances with enhancing magnetic parameter while reduces with enhancing velocity ratio parameter. Also the Nusselt number was found to directly depend on the velocity ratio and temperature index parameters but has an inverse dependence on the magnetic and radiation parameters.
文摘The current work is being done to investigate the flow of nanofluids across a porous exponential stretching surface in the presence of a heat source/sink,thermophoretic particle deposition,and bioconvection.The collection of PDEs(partial differential equations)that represent the fluid moment is converted to a system of ODEs(ordinary differential equations)with the use of suitable similarity variables,and these equations are then numerically solved using Runge Kutta Fehlberg and the shooting approach.For different physical limitations,the numerical results are visually represented.The results show that increasing the porosity characteristics reduces velocity.The mass transfer decreases as the thermophoretic limitation increases.Increases in the porosity parameter reduce skin friction,increases in the solid volume fraction improve the rate of thermal distribution,and increases in the thermophoretic parameter increase the rate of mass transfer.
基金The work described here was funded by the Next Generation Synthesis Center(GENESIS),an Energy Frontier Research Center funded by the U.S.Department of Energy,Office of Science,Basic Energy Sciences under Award Number DE-SC0019212X-ray PDF measurements were conducted on beamline 28-ID-2 of the National Synchrotron Light Source II,a US DOE Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under contract No.DESC0012704+1 种基金Q.D.is also partially supported by DOEASCRDE-SC0022317G.E.K received training and support as a part of QuADS:Quantitative Analysis of Dynamic Structures National Science Foundation Research Traineeship Program,grant number NSF DGE 1922639.
文摘A novel algorithm,STRETCHEDNMF,is introduced for non-negative matrix factorization(NMF),accounting for signal stretching along the independent variable’s axis.It addresses signal variability caused by stretching,proving beneficial for analyzing data such as powder diffraction at varying temperatures.This approach provides a more meaningful decomposition,particularly when the component signals resemble those from chemical components in the sample.The STRETCHEDNMF model introduces a stretching factor to accommodate signal expansion,solved using discretization and Block Coordinate Descent algorithms.Initial experimental results indicate that the STRETCHEDNMF model outperforms conventional NMF for datasets exhibiting such expansion.An enhanced version,SPARSE-STRETCHEDNMF,optimized for powder diffraction data from crystalline materials,leverages signal sparsity for accurate extraction,especially with small stretches.Experimental results showcase its effectiveness in analyzing diffraction data,including success in real-time chemical reaction experiments.
