期刊文献+
共找到665篇文章
< 1 2 34 >
每页显示 20 50 100
Radiative Flow of Ag-Fe_(3)O_(4)/Water Hybrid Nanofluids Induced by a Shrinking/Stretching Disk with Influence of Velocity and Thermal Slip Conditions
1
作者 Muhammad Zubair Mustafa Sumera Dero +2 位作者 Liaquat Ali Lund Mehboob Ul Hassan Umair Khan 《Computer Modeling in Engineering & Sciences》 2025年第4期499-513,共15页
This paper discusses the model of the boundary layer(BL)flow and the heat transfer characteristics of hybrid nanofluid(HNF)over shrinking/stretching disks.In addition,the thermal radiation and the impact of velocity a... This paper discusses the model of the boundary layer(BL)flow and the heat transfer characteristics of hybrid nanofluid(HNF)over shrinking/stretching disks.In addition,the thermal radiation and the impact of velocity and thermal slip boundary conditions are also examined.The considered hybrid nano-fluid contains silver(Ag)and iron oxide(Fe_(3)O_(4))nanoparticles dispersed in the water to prepare the Ag-Fe_(3)O_(4)/water-based hybrid nanofluid.The requisite posited partial differential equations model is converted to ordinary differential equations using similarity transformations.For a numerical solution,the shooting method in Maple is employed.Moreover,the duality in solutions is achieved for both cases of the disk(stretching(λ>0)and shrinking(λ<0)).At the same time,a unique solution is observed for λ=0.No solution is found for them at λ<λ_(c),whereas the solutions are split at the λ=λ_(c).Besides,the value of the λ_(c) is dependent on the φ_(hnf).Meanwhile,the values of f″(0)and -θ′(0)intensified with increasing φ_(hnf).Stability analysis has been applied using bvp4c in MATLAB software due to a dual solution.Furthermore,analysis shows that the first solution is stable and feasible physically.For the slip parameters,an increase in the velocity slip parameter increases the velocity and shear stress profiles while increasing the temperature profile in the first solutions.While the rise in thermal slip parameter reduces the temperature profile nanoparticle volume fractions increase it. 展开更多
关键词 Dual solutions slip and radiation hybrid nanofluid shrinking/stretching disk stability analysis
在线阅读 下载PDF
Role of Stretching-induced Crystallization on Mesoscale Morphology Transition of UHMWPE during Hot Stretching
2
作者 Kai Huang Jia-Jia Mo +5 位作者 Wen-Jing Shi Shi-Tong Wang Hong-Hui Shi Chun-Guang Shao Chun-Tai Liu Bao-Bao Chang 《Chinese Journal of Polymer Science》 2025年第1期188-198,I0013,共12页
In this work,a morphology transition mode is revealed in ultra-high molecular weight polyethylene(UHMWPE)when stretching at 120℃:moving from the slightly deformed region to the necked region,the morphology transfers ... In this work,a morphology transition mode is revealed in ultra-high molecular weight polyethylene(UHMWPE)when stretching at 120℃:moving from the slightly deformed region to the necked region,the morphology transfers from small spherulites to a mixture of transcrystalline and enlarged spherulites,and finally to pure transcrystalline;meanwhile,the lamellae making up the transcrystalline or spherulite were fragmented into smaller ones;spatial scan by wide-angle X-ray scattering(WAXS)and small angle X-ray scattering(SAXS)revealed that the crystallinity is increased from 25.3%to 30.1%and the crystal orientation was enhanced greatly,but the lamellae orientation was quite weak.The rise of enlarged spherulites or a mixture of transcrystalline and spherulites can also be found in UHMWPE stretched at 140 and 148℃,whereas absent in UHMWPE stretched at 30℃.In situ WAXS/SAXS measurements suggest that during stretching at 30℃,the crystallinity is reduced drastically,and a few voids are formed as the size increases from 50 nm to 210 nm;during stretching at 120℃,the crystallinity is reduced only slightly,and the kinking of lamellae occurs at large Hencky strain;during stretching at 140 and 148℃,an increase in crystallinity with stretching strain can be found,and the lamellae are also kinked.Taking the microstructure and morphology transition into consideration,a mesoscale morphology transition mode is proposed,in the stretching-induced crystallization the fragmented lamellae can be rearranged into new supra-structures such as spherulite or transcrystalline during hot stretching. 展开更多
关键词 UHMWPE stretching induced crystallization Lamellae fragmentation Mesoscale structural transition
原文传递
Influence of β-Phase Content on the Stretching-induced α-β Phase Transition of Highly Oriented Poly(vinylidene fluoride)Ultrathin Films
3
作者 Hai-Peng Li Jia-Meng Liang +6 位作者 Rui-Hao Zheng Han-Qi Zhu Wen-Peng Zhao Yun-Peng Li Shao-Juan Wang Hao Zhang Shou-Ke Yan 《Chinese Journal of Polymer Science》 2025年第8期1406-1414,共9页
Highly oriented poly(vinylidene fluoride)(PVDF)ultrathin films with differentβ-phase contents were prepared using the melt-draw method.The effect ofβ-phase content onα-βphase transition of highly oriented PVDF ult... Highly oriented poly(vinylidene fluoride)(PVDF)ultrathin films with differentβ-phase contents were prepared using the melt-draw method.The effect ofβ-phase content onα-βphase transition of highly oriented PVDF ultrathin films induced by stretching was investigated using transmission electron microscopy(TEM)and Fourier transform infrared(FTIR)spectroscopy.The results show that stretching can enhance the crystallinity and increase the average thickness of the lamellae.A fullα-βphase transition can be achieved for PVDF ultrathin films of 20.6%βphase stretched to aλ(stretching ratio)of 1.5,while fewαphases still exist for ultrathin films of 35.0%βphase,together with bent and tilted lamellae.Compared to thicker PVDF films undergoing stretching-inducedα-βphase transition,the higherα-βphase transition efficiency of the PVDF ultrathin films can be attributed to the parallel aligned lamellar structure.Moreover,a higherβ-phase content can suppressα-βphase transition because of the stress concentration effect ofβ-phase.Ultimately,these results provide valuable insights into the stretching-inducedα-βphase transition of PVDF ultrathin films. 展开更多
关键词 Poly(vinylidene fluoride) stretching α-βphase transition β-phase content
原文传递
Practical recommendations on stretching exercise:A Delphi consensus statement of international research experts
4
作者 Konstantin Warneke Ewan Thomas +17 位作者 Anthony J.Blazevich José Afonso David G.Behm Paulo H.Marchetti Gabriel S.Trajano Masatoshi Nakamura Francisco Ayala Stefano Longo Nicolas Babault Sandro R.Freitas Pablo B.Costa Andreas Konrad Antoine Nordez Arnold Nelson Astrid Zech Anthony D.Kay Olyvia Dontit Jan Wilke 《Journal of Sport and Health Science》 2025年第5期110-123,共14页
Background:Stretching has wide appeal,but there seems to exist some mismatch between its purported applications and what the evidence shows.There is compelling evidence for some stretching applications,but for others,... Background:Stretching has wide appeal,but there seems to exist some mismatch between its purported applications and what the evidence shows.There is compelling evidence for some stretching applications,but for others,the evidence seems heterogeneous or unsupportive.The discrepancies even affect some systematic reviews,possibly due to heterogeneous eligibility criteria and search strategies.This consensus paper seeks to unify the divergent findings on stretching and its implications for both athletic performance and clinical practices by delivering evidence-based recommendations.Methods:A panel of 20 experts with a blend of practical experience and scholarly knowledge was assembled.The panel meticulously reviewed existing systematic reviews,defined key terminologies(e.g.,consensus definitions for different stretching modes),and crafted guidelines using a Delphi consensus approach(minimum required agreement:80%).The analysis focused on 8 topics,including stretching's acute and chronic(long-term)effects on range of motion,strength performance,muscle hypertrophy,stiffness,injury prevention,muscle recovery,posture correction,and cardiovascular health.Results:There was consensus that chronic and acute stretching(a)improves range of motion(although alternatives exist)and(b)reduces muscle stiffness(which may not always be desirable);the panel also agreed that chronic stretching(c)may promote vascular health,but more research is warranted.In contrast,consensus was found that stretch training does not(a)contribute substantively to muscle growth,(b)serve as an allencompassing injury prevention strategy,(c)improve posture,or(d)acutely enhance post-exercise recovery.Conclusion:These recommendations provide guidance for athletes and practitioners,highlighting research gaps that should be addressed to more comprehensively understand the full scope of stretching effects. 展开更多
关键词 Range of motion Strength Movement preparation Recovery Evidence-based practice STRETCH
在线阅读 下载PDF
Numerical Analysis of Entropy Generation in Joule Heated Radiative Viscous Fluid Flow over a Permeable Radially Stretching Disk
5
作者 Tahir Naseem Fateh Mebarek-Oudina +3 位作者 Hanumesh Vaidya Nagina Bibi Katta Ramesh Sami Ullah Khan 《Computer Modeling in Engineering & Sciences》 2025年第4期351-371,共21页
Maximizing the efficiency of thermal engineering equipment involves minimizing entropy generation,which arises from irreversible processes.This study examines thermal transport and entropy generation in viscous flow o... Maximizing the efficiency of thermal engineering equipment involves minimizing entropy generation,which arises from irreversible processes.This study examines thermal transport and entropy generation in viscous flow over a radially stretching disk,incorporating the effects of magnetohydrodynamics(MHD),viscous dissipation,Joule heating,and radiation.Similarity transformations are used to obtain dimensionless nonlinear ordinary differential equations(ODEs)from the governing coupled partial differential equations(PDEs).The converted equations are then solved by using the BVP4C solver in MATLAB.To validate the findings,the results are compared with previously published studies under fixed parameter conditions,demonstrating strong agreement.Various key parameters are analyzed graphically to assess their impact on velocity and temperature distributions.Additionally,Bejan number and entropy generation variations are presented for different physical parameters.The injection parameter(S<0)increases the heat transfer rate,while the suction parameter(S>0)reduces it,exhibiting similar effects on fluid velocity.The magnetic parameter(M)effectively decreases entropy generation within the range of approximately 0≤η≤0.6.Beyond this interval,its influence diminishes as entropy generation values converge,with similar trends observed for the Bejan number.Furthermore,increased thermal radiation intensity is identified as a critical factor in enhancing entropy generation and the Bejan number. 展开更多
关键词 Partial differential equations modeling stretched surface joule heating viscous dissipation radiation suction/injection
在线阅读 下载PDF
Chronic effects of stretching on range of motion with consideration of potential moderating variables:A systematic review with meta-analysis 被引量:2
6
作者 Andreas Konrad Shahab Alizadeh +7 位作者 Abdolhamid Daneshjoo Saman Hadjizadeh Anvar Andrew Graham Ali Zahiri Reza Goudini Chris Edwards Carina Scharf David George Behm 《Journal of Sport and Health Science》 SCIE CAS CSCD 2024年第2期186-194,共9页
Background:It is well known that stretch training can induce prolonged increases in joint range of motion(ROM).However,to date more information is needed regarding which training variables might have greater influence... Background:It is well known that stretch training can induce prolonged increases in joint range of motion(ROM).However,to date more information is needed regarding which training variables might have greater influence on improvements in flexibility.Thus,the purpose of this metaanalysis was to investigate the effects of stretch training on ROM in healthy participants by considering potential moderating variables,such as stretching technique,intensity,duration,frequency,and muscles stretched,as well as sex-specific,age-specific,and/or trained state-specific adaptations to stretch training.Methods:We searched through PubMed,Scopus,Web of Science,and SportDiscus to find eligible studies and,finally,assessed the results from 77 studies and 186 effect sizes by applying a random-effect meta-analysis.Moreover,by applying a mixed-effect model,we performed the respective subgroup analyses.To find potential relationships between stretch duration or age and effect sizes,we performed a meta-regression.Results:We found a significant overall effect,indicating that stretch training can increase ROM with a moderate effect compared to the controls(effect size=-1.002;Z=-12.074;95%confidence interval:-1.165 to-0.840;p<0.001;I^(2)=74.97).Subgroup analysis showed a significant difference between the stretching techniques(p=0.01)indicating that proprioceptive neuromuscular facilitation and static stretching produced greater ROM than did ballistic/dynamic stretching.Moreover,there was a significant effect between the sexes(p=0.04),indicating that females showed higher gains in ROM compared to males.However,further moderating analysis showed no significant relation or difference.Conclusion:When the goal is to maximize ROM in the long term,proprioceptive neuromuscular facilitation or static stretching,rather than ballistic/dynamic stretching,should be applied.Something to consider in future research as well as sports practice is that neither volume,intensity,nor frequency of stretching were found to play a significant role in ROM yields. 展开更多
关键词 FLEXIBILITY Long-term stretching Stretch training
在线阅读 下载PDF
Exact solutions for magnetohydrodynamic nanofluids flow and heat transfer over a permeable axisymmetric radially stretching/shrinking sheet
7
作者 U.S.Mahabaleshwar G.P.Vanitha +2 位作者 L.M.Pérez Emad H.Aly I.Pop 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第2期108-114,共7页
We report on the magnetohydrodynamic impact on the axisymmetric flow of Al_(2)O_(3)/Cu nanoparticles suspended in H_(2)O past a stretched/shrinked sheet.With the use of partial differential equations and the correspon... We report on the magnetohydrodynamic impact on the axisymmetric flow of Al_(2)O_(3)/Cu nanoparticles suspended in H_(2)O past a stretched/shrinked sheet.With the use of partial differential equations and the corresponding thermophysical characteristics of nanoparticles,the physical flow process is illustrated.The resultant nonlinear system of partial differential equations is converted into a system of ordinary differential equations using the suitable similarity transformations.The transformed differential equations are solved analytically.Impacts of the magnetic parameter,solid volume fraction and stretching/shrinking parameter on momentum and temperature distribution have been analyzed and interpreted graphically.The skin friction and Nusselt number were also evaluated.In addition,existence of dual solution was deduced for the shrinking sheet and unique solution for the stretching one.Further,Al_(2)O_(3)/H_(2)O nanofluid flow has better thermal conductivity on comparing with Cu/H_(2)O nanofluid.Furthermore,it was found that the first solutions of the stream are stable and physically realizable,whereas those of the second ones are unstable. 展开更多
关键词 MAGNETOHYDRODYNAMIC NANOFLUID stretching/shrinking sheet axisymmetric flow analytical solution suction/injection
原文传递
Structural Evolution of Ultra-High Molecular Weight Polyethylene Low-Entangled Films with Reserved Shish Crystals During Hot Stretching
8
作者 Jia-Wei Gao Li Chen +3 位作者 Ye-Shun Zhong Chao-Wei Xing Yi-Guo Li Zong-Bao Wang 《Chinese Journal of Polymer Science》 SCIE EI CAS CSCD 2024年第8期1227-1242,共16页
Shish crystals are crucial to achieving high performance low-dimensional ultra-high molecular weight polyethylene(UHMWPE)products.Typically,high stretch and shear flow fields are necessary for the formation of shish c... Shish crystals are crucial to achieving high performance low-dimensional ultra-high molecular weight polyethylene(UHMWPE)products.Typically,high stretch and shear flow fields are necessary for the formation of shish crystals.In this study,UHMWPE gel films with reserved shish crystals were prepared by gel molding,the structural evolution and properties of UHMWPE films stretched at temperatu res of 100,110,120and 130℃were investigated by in situ small-angle X-ray scattering(SAXS)/ultra-small-angle X-ray scattering(USAXS)/wide-angle X-ray diffraction(WAXD)measu rements as well as scanning electron microscopy(SEM)and differential scanning calorimetry(DSC)measurements.Our findings showed that the reserved shish crystals can facilitate the formation and structural evolution of shish-kebab crystals during the hot stretching.Additionally,the reserved shish crystals promote the structu ral evolution of UHMWPE films to a greater extent when stretched at 120 and 130℃,compared to 100 and 110℃,resulting in higher crystallinity,orientation,thermal properties,breaking strength and Young's modulus.Com pared to UHMWPE high-entangled films with reserved shish crystals prepared by compression molding,UHMWPE low-entangled films with reserved shish crystals prepared by gel molding are more effective in inducing the formation and evolution of shish-kebab crystals during the hot stretching,resulting in increased breaking strength and Young's modulus. 展开更多
关键词 UHMWPE low-entangled films Reserved shish crystals Structural evolution Hot stretching
原文传递
Impact of a Magnetic Dipole on Heat Transfer in Non-Conducting Magnetic Fluid Flow over a Stretching Cylinder
9
作者 Anupam Bhandari 《Fluid Dynamics & Materials Processing》 EI 2024年第3期475-486,共12页
The thermal behavior of an electrically non-conducting magnetic liquid flowing over a stretching cylinder under the influence of a magnetic dipole is considered.The governing nonlinear differential equations are solve... The thermal behavior of an electrically non-conducting magnetic liquid flowing over a stretching cylinder under the influence of a magnetic dipole is considered.The governing nonlinear differential equations are solved numerically using a finite element approach,which is properly validated through comparison with earlier results available in the literature.The results for the velocity and temperature fields are provided for different values of the Reynolds number,ferromagnetic response number,Prandtl number,and viscous dissipation parameter.The influence of some physical parameters on skin friction and heat transfer on the walls of the cylinder is also investigated.The applicability of this research to heat control in electronic devices is discussed to a certain extent. 展开更多
关键词 FERROFLUID stretching cylinder finite element method heat transfer magnetic dipole
在线阅读 下载PDF
A new model of flow over stretching(shrinking)and porous sheet with its numerical solutions
10
作者 Azhar Ali Dil Nawaz Khan Marwat Saleem Asghar 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2024年第3期381-397,共17页
The viscous fluid flow and heat transfer over a stretching(shrinking)and porous sheets of nonuniform thickness are investigated in this paper.The modeled problem is presented by utilizing the stretching(shrinking)and ... The viscous fluid flow and heat transfer over a stretching(shrinking)and porous sheets of nonuniform thickness are investigated in this paper.The modeled problem is presented by utilizing the stretching(shrinking)and porous velocities and variable thickness of the sheet and they are combined in a relation.Consequently,the new problem reproduces the different available forms of flow motion and heat transfer maintained over a stretching(shrinking)and porous sheet of variable thickness in one go.As a result,the governing equations are embedded in several parameters which can be transformed into classical cases of stretched(shrunk)flows over porous sheets.A set of general,unusual and new variables is formed to simplify the governing partial differential equations and boundary conditions.The final equations are compared with the classical models to get the validity of the current simulations and they are exactly matched with each other for different choices of parameters of the current problem when their values are properly adjusted and manipulated.Moreover,we have recovered the classical results for special and appropriate values of the parameters(δ_(1),δ_(2),δ_(3),c,and B).The individual and combined effects of all inputs from the boundary are seen on flow and heat transfer properties with the help of a numerical method and the results are compared with classical solutions in special cases.It is noteworthy that the problem describes and enhances the behavior of all field quantities in view of the governing parameters.Numerical result shows that the dual solutions can be found for different possible values of the shrinking parameter.A stability analysis is accomplished and apprehended in order to establish a criterion for the determinations of linearly stable and physically compatible solutions.The significant features and diversity of the modeled equations are scrutinized by recovering the previous problems of fluid flow and heat transfer from a uniformly heated sheet of variable(uniform)thickness with variable(uniform)stretching/shrinking and injection/suction velocities. 展开更多
关键词 permeable stretching(shrinking)sheets sheet of variable thickness heat transfer numerical(dual)solutions stability analysis
在线阅读 下载PDF
Chemically Radiative MHD Flow of a Micropolar Nanofluid over a Stretching/ Shrinking Sheet with a Heat Source or Sink
11
作者 Parakapali Roja Shaik Mohammed Ibrahim +1 位作者 Thummala Sankar Reddy Giulio Lorenzini 《Fluid Dynamics & Materials Processing》 EI 2024年第2期257-274,共18页
This study examines the behavior of a micropolar nanofluidflowing over a sheet in the presence of a transverse magneticfield and thermal effects.In addition,chemical(first-order homogeneous)reactions are taken into accoun... This study examines the behavior of a micropolar nanofluidflowing over a sheet in the presence of a transverse magneticfield and thermal effects.In addition,chemical(first-order homogeneous)reactions are taken into account.A similarity transformation is used to reduce the system of governing coupled non-linear partial differ-ential equations(PDEs),which account for the transport of mass,momentum,angular momentum,energy and species,to a set of non-linear ordinary differential equations(ODEs).The Runge-Kutta method along with shoot-ing method is used to solve them.The impact of several parameters is evaluated.It is shown that the micro-rota-tional velocity of thefluid rises with the micropolar factor.Moreover,the radiation parameter can have a remarkable influence on theflow and temperature profiles and on the angular momentum distribution. 展开更多
关键词 Chemical(first order homogeneous)reaction MAGNETOHYDRODYNAMICS MICROPOLAR nanofluid stretching/shrinking sheet heat source
在线阅读 下载PDF
Mixed convectional and chemical reactive flow of nanofluid with slanted MHD on moving permeable stretching/shrinking sheet through nonlinear radiation,energy omission
12
作者 Saleem Nasir Sekson Sirisubtawee +1 位作者 Pongpol Juntharee Taza Gul 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第5期193-202,共10页
Hybrid nanofluids are remarkable functioning liquids that are intended to reduce the energy loss while maximizing the heat transmission.In the involvement of suction and nonlinear thermal radiation effects,this study ... Hybrid nanofluids are remarkable functioning liquids that are intended to reduce the energy loss while maximizing the heat transmission.In the involvement of suction and nonlinear thermal radiation effects,this study attempted to explore the energy transmission features of the inclined magnetohydrodynamic(MHD)stagnation flow of CNTs-hybrid nanofluid across the nonlinear permeable stretching or shrinking sheet.This work also included some noteworthy features like chemical reactions,variable molecular diffusivity,quadratic convection,viscous dissipation,velocity slip and heat omission assessment.Employing appropriate similarity components,the model equations were modified to ODEs and computed by using the HAM technique.The impact of various relevant flow characteristics on movement,heat and concentration profiles was investigated and plotted on a graph.Considering various model factors,the significance of drag friction,heat and mass transfer rate were also computed in tabular and graphical form.This leads to the conclusion that such factors have a considerable impact on the dynamics of fluid as well as other engineering measurements of interest.Furthermore,viscous forces are dominated by increasing the values ofλ_(p),δ_(m)andδ_(q),and as a result,F(ξ)accelerates while the opposite trend is observed for M andφ.The drag friction is boosted by the augmentation M,λ_(p)andφ,but the rate of heat transfer declined.According to our findings,hybrid nanoliquid effects dominate that of ordinary nanofluid in terms of F(ξ),Θ(ξ)andφ(ξ)profiles.The HAM and the numerical technique(shooting method)were found to be in good agreement. 展开更多
关键词 hybrid nanofluid(SWCNT+MWCNT/H_(2)O) velocity slip conditions nonlinear thermal radiation exponential stretching/shrinking sheet inclined magnetohydrodynamic(MHD)stagnation flow
原文传递
Chemical Reaction on Williamson Nanofluid’s Radiative MHD Dissipative Stagnation Point Flow over an Exponentially Inclined Stretching Surface with Multi-Slip Effects
13
作者 P.Saila Kumari S.Mohammed Ibrahim Giulio Lorenzini 《Frontiers in Heat and Mass Transfer》 EI 2024年第6期1839-1863,共25页
A wide range of technological and industrial domains,including heating processors,electrical systems,mechanical systems,and others,are facing issues as a result of the recent developments in heat transmission.Nanoflui... A wide range of technological and industrial domains,including heating processors,electrical systems,mechanical systems,and others,are facing issues as a result of the recent developments in heat transmission.Nanofluids are a novel type of heat transfer fluid that has the potential to provide solutions that will improve energy transfer.The current study investigates the effect of a magnetic field on the two-dimensional flow of Williamson nanofluid over an exponentially inclined stretched sheet.This investigation takes into account the presence of multi-slip effects.We also consider the influence of viscous dissipation,thermal radiation,chemical reactions,and suction on the fluid’s velocity.We convert the nonlinear governing partial differential equations(PDEs)of the fluid flow problem into dimensionless ordinary differential equations(ODEs)through the utilization of similarity variables.We then use the homotopy analysis method(HAM)to numerically solve the resulting ordinary differential equations(ODEs).We demonstrate the effects of numerous elements on a variety of profiles through graphical and tabular representations.We observe a drop in the velocity profile whenever we increase either the magnetic number or the suction parameter.Higher values of the Williamson parameter lead to an increase in the thermal profile,while the momentum of the flow displays a trend in the opposite direction.The potential applications of this unique model include chemical and biomolecule detection,environmental cleansing,and the initiation of radiation-induced chemical processes like polymerization,sterilization,and chemical synthesis. 展开更多
关键词 Williamson fluid NANOFLUID exponentially inclined stretching surface slip conditions HAM
在线阅读 下载PDF
Removing Fermi resonance through deuterated molecules with single C-H bond in C-H stretching region of Raman spectra
14
作者 Nisar Ullah Zhirun Jiao +4 位作者 Jialin Bai Zhiqiang Wang Ruiting Zhang Lin Ma Ke Lin 《Chinese Journal of Chemical Physics》 CSCD 2024年第6期783-791,I0011-I0013,I0042,共13页
The Raman spectra in the C-H stretching region are of great importance for the study of the structure and dynamics of organic compounds.However,the Fermi resonance between the first overtone mode of C-H bending vibrat... The Raman spectra in the C-H stretching region are of great importance for the study of the structure and dynamics of organic compounds.However,the Fermi resonance between the first overtone mode of C-H bending vibration and C-H stretching vibration typically results in the disturbance of Raman bands in the C-H stretching region.In this context,a specific deuterated molecule with only one C-H bond was proposed,and it was found that the frequency of the first overtone mode of the C-H bending vibration was significantly different from the frequency of the C-H stretching vibration.Due to the significant discrepancy,Fermi resonance in the C-H stretching region was eliminated from the experimental and theoretical Raman spectra of deuterated leucine,deuterated benzoin,deuterated methanol,and deuterated ethanol.Hence then,the Raman spectra of these specific deuterated compounds in the C-H stretching region can be used to study the structure or the dynamics of the organic compounds. 展开更多
关键词 Fermi resonance C-H stretching vibration Raman spectra C-H bending vibration OVERTONE
在线阅读 下载PDF
Static Stretching Combined with Conscious Slower Breathing May Increase Parasympathetic Activity and Reduce Stress in Adult Women
15
作者 Mami Sakurai Yasushi Ikarashi +3 位作者 Masahiro Tabuchi Ailing Hu Takuji Yamaguchi Hiroyuki Kobayashi 《Health》 2024年第3期242-256,共15页
Background: Women are thought to be more susceptible to stress than men in a stressful society, and reducing stress is crucial for women to maintain their health. Static stretching (SST) is applied in various fields t... Background: Women are thought to be more susceptible to stress than men in a stressful society, and reducing stress is crucial for women to maintain their health. Static stretching (SST) is applied in various fields to not only increase muscle flexibility but also reduce stress. Additionally, conscious slower breathing (CSB) predominates parasympathetic activity, causing a relaxing effect. These results indicate that combining SST and CSB may be more useful in reducing stress. However, to the best of our knowledge, the effect of this combination remains unclear. Objective: This study aimed to elucidate the effects of the combination of SST and CSB on autonomic activity and stress in adult women. Methods: Eleven healthy Japanese adult female participants performed SST with nonconscious natural breathing for 20 min. The same participants performed SST in combination with CSB (2 s inspiratory and 4 s expiratory) for 20 min on another day. Salivary cortisol and chromogranin A levels were measured before and after stretching as stress markers of the hypothalamic-pituitary-adrenal axis and sympathetic nervous system. The coefficient of variation of the R-R interval (CVR-R) and high-frequency component (HF), which reflect parasympathetic nerve activity, and heart rate and low-frequency component (LF)/HF ratio, which reflect sympathetic nerve activity, were measured before, during, and after stretching. Results: SST decreased cortisol levels but with no significant changes in chromogranin A, heart rate, CVR-R, HF, or LF/HF ratio. The combination of SST and CSB increased CVR-R and HF levels in addition to decreasing cortisol levels but with no significant changes in chromogranin A, heart rate, or LF/HF levels. Conclusion: These results indicate that the combination of SST and CSB may increase parasympathetic activity and reduce stress. However, future randomized controlled trials with larger sample sizes should support this conclusion. 展开更多
关键词 Static stretching Conscious Slower Breathing Autonomic Activity Heart Rate Variability STRESS
在线阅读 下载PDF
Cut layout optimization for design of kirigami metamaterials under largestretching
16
作者 Chen Du Yiqiang Wang Zhan Kang 《Theoretical & Applied Mechanics Letters》 CSCD 2024年第6期460-466,共7页
Kirigami metamaterials have gained increasing attention due to their unusual mechanical properties under largestretching.However,most metamaterial designs obtained with trial-and-error approaches tend to lose their de... Kirigami metamaterials have gained increasing attention due to their unusual mechanical properties under largestretching.However,most metamaterial designs obtained with trial-and-error approaches tend to lose their desirable properties under large tensile strains due to occurrence of instability caused by out-of-plane buckling.To cope with this limitation,this paper presents a systematic approach of cut layout optimizing for designingkirigami metamaterials working at large tensile strains by fully exploiting their out-of-plane buckling behaviors.This method can also mitigate the local stress concentration issue at the hinges of conventional kirigami designsworking at in-plane deformation modes.The effectiveness of the proposed method is demonstrated through several examples regarding metamaterial design with negative Poisson’s ratio and specified flip angle pattern.It isshown that the proposed method is capable of addressing the highly nonlinear deformation impacts on the mechanical performance under large stretching,to meet the growing and diverse demands in the field of kirigamimetamaterials. 展开更多
关键词 Kirigami metamaterial Layout optimization Out-of-plane buckling Large stretching
在线阅读 下载PDF
Casson Nanofluid Flow with Cattaneo-Christov Heat Flux and Chemical Reaction Past a Stretching Sheet in the Presence of Porous Medium
17
作者 Mahzad Ahmed Raja Mussadaq Yousaf +1 位作者 Ali Hassan B.Shankar Goud 《Frontiers in Heat and Mass Transfer》 EI 2024年第4期1261-1276,共16页
In the current work,inclined magnetic field,thermal radiation,and the Cattaneo-Christov heat flux are taken into account as we analyze the impact of chemical reaction on magneto-hydrodynamic Casson nanofluid flow on a... In the current work,inclined magnetic field,thermal radiation,and the Cattaneo-Christov heat flux are taken into account as we analyze the impact of chemical reaction on magneto-hydrodynamic Casson nanofluid flow on a stretching sheet.Modified Buongiorno’s nanofluid model has been used to model the flow governing equations.The stretching surface is embedded in a porousmedium.By using similarity transformations,the nonlinear partial differential equations are transformed into a set of dimensionless ordinary differential equations.The numerical solution of transformed dimensionless equations is achieved by applying the shooting procedure together with Rung-Kutta 4th-order method employing MATLAB.The impact of significant parameters on the velocity profile f(ζ),temperature distributionθ(ζ),concentration profileϕ(ζ),skin friction coefficient(Cf),Nusselt number(Nux)and Sherwood number(Shx)are analyzed and displayed in graphical and tabular formats.With an increase in Casson fluid 0.5<β<2,the motion of the Casson fluid decelerates whereas the temperature profile increases.As the thermal relation factor expands 0.1<γ1<0.4,the temperature reduces,and consequently thermal boundary layer shrinks.Additionally,by raising the level of thermal radiation 1<Rd<7,the temperature profile significantly improves,and an abrupt expansion has also been observed in the associated thermal boundary with raise thermal radiation strength.It was observed that higher permeability 0<K<4 hinders the acceleration of Casson fluid.Higher Brownian motion levels 0.2<Nb<0.6 correspond to lower levels of the Casson fluid concentration profile.Moreover,it is observed that chemical reaction 0.2<γ2<0.5 has an inverse relation with the concentration level of Casson fluid.The current model’s significant uses include heat energy enhancement,petroleum recovery,energy devices,food manufacturing processes,and cooling device adjustment,among others.Furthermore,present outcomes have been found in great agreementwith already publishedwork. 展开更多
关键词 NANOFLUID Cattaneo-Christov heat flux stretching sheet porous medium rosseland radiation and first order chemical reaction
在线阅读 下载PDF
Exploring Combined Immune Mechanisms of Acupuncture and Stretching—A Narrative Review
18
作者 Yiping Zhou Thelander Huijun Z. Ring +4 位作者 Guikang Wei Yingqiu Wang Yinghua He Sheyian Bai Haisheng Zhang 《Health》 2024年第12期1268-1288,共21页
This narrative review explores the synergistic anti-inflammatory mechanisms of acupuncture and stretching. Acupuncture induces mechanical forces that activate neuro-immune pathways, modulating immune cell functions an... This narrative review explores the synergistic anti-inflammatory mechanisms of acupuncture and stretching. Acupuncture induces mechanical forces that activate neuro-immune pathways, modulating immune cell functions and enhancing anti-inflammatory cytokine secretion. Through tissue tension, stretching promotes fibroblast activity and macrophage polarization, further amplifying anti-inflammatory responses. Together, these interventions strengthen macrophage activity, accelerate tissue repair, and improve treatment outcomes for chronic inflammation, sports injuries, and cancer recovery. This review consolidates experimental evidence to provide a theoretical basis for advancing research into fascial acupuncture and its clinical applications. 展开更多
关键词 ACUPUNCTURE Anti-Inflammatory Mechanisms FIBROBLASTS MACROPHAGES Mast Cells stretching
暂未订购
Immediate Effects of Calf Muscle Release via Foam Rolling and Active Stretching on Blood Pressure, Heart Rate and the Rate Pressure Product in People with High-Normal Blood Pressure - A Comparative Study
19
作者 Nidhi Mevada Mihir Mehta +1 位作者 Falak Oza Jil Chokshi 《Cardiovascular Innovations and Applications》 2024年第1期400-409,共10页
Background and need for the research:High-normal blood pressure(i.e.,130–139/85–89 mmHg)hashazardous ratio for both coronary heart disease and stroke,because of day to day variations in blood pressure;consequently,p... Background and need for the research:High-normal blood pressure(i.e.,130–139/85–89 mmHg)hashazardous ratio for both coronary heart disease and stroke,because of day to day variations in blood pressure;consequently,prevention through lifestyle modification is essential.Although numerous studies have examined stretching and myo-fascial release to lower blood pressure,no consensus has been reached regarding which technique is superior for immediate lowering blood pressure.The aim of this study was to evaluate and compare the immediate effects of self-performed foam rolling and active-stretching on blood pressure and myocardial oxygen demand.Methods:A total of 98 patients with high normal blood pressure(20–40 years of age)meeting the inclusion criteria were randomly divided into two groups.Group 1(n=49)performed foam rolling,and group 2(n=49)performed TheraBand-assisted active stretching of the calf muscle.The pre and post blood pressure,heart rate,and the rate pres-sure product were assessed.Statistical analysis was conducted in SPSS software(version 20.0).Results:Systolic and diastolic blood pressure significantly decreased in both groups(P<0.05),and the decrease was greater in the active stretching group than the foam rolling group.In the foam rolling group,the heart rate signifi-cantly increased,whereas no changes were observed in the active stretching group.The Rate Pressure Product was notsignificant within and between two groups.Conclusion and clinical implications:Active stretching as part of a self-performed daily exercise routineappears safer for immediate lowering blood pressure,without affecting myocardial oxygen demand.Ethics committee approval:Reference No.:EC/Approval/08/Physio/21/06/2023. 展开更多
关键词 Active stretching Blood pressure Foam rolling High normal blood pressure
暂未订购
Hybrid Nanofluid Flow over a Stretching Curved Surface with Induced Magnetic Field and Homogeneous-Heterogeneous Reactions
20
作者 Ming Shen Yunhua Zheng +2 位作者 Yihong Liu Hui Chen Mengchen Zhang 《Journal of Applied Mathematics and Physics》 2024年第10期3638-3654,共17页
This study explores the 2D stretching flow of a hybrid nanofluid over a curved surface influenced by a magnetic field and reactions. A steady laminar flow model is created with curvilinear coordinates, considering the... This study explores the 2D stretching flow of a hybrid nanofluid over a curved surface influenced by a magnetic field and reactions. A steady laminar flow model is created with curvilinear coordinates, considering thermal radiation, suction, and magnetic boundary conditions. The nanofluid is made of water with copper and MWCNTs as nanoparticles. The equations are transformed into nonlinear ODEs and solved numerically. The model’s accuracy is confirmed by comparing it with published data. Results show that fluid velocity increases, temperature decreases, and concentration increases with the curvature radius parameter. The hybrid nanofluid is more sensitive to magnetic field changes in velocity, while the nanofluid is more sensitive to magnetic boundary coefficient changes. These insights can optimize heat and mass transfer in industrial processes like chemical reactors and wastewater treatment. 展开更多
关键词 Hybrid Nanofluids stretching Curved Surface Induced Magnetic Field Improved Shooting Method
在线阅读 下载PDF
上一页 1 2 34 下一页 到第
使用帮助 返回顶部