Concentration gradient and fluid shear stress(FSS)for cell microenvironment were investigated through microfluidic technology.The Darcy–Weisbach equation combined with computational fluid dynamics modeling was exploi...Concentration gradient and fluid shear stress(FSS)for cell microenvironment were investigated through microfluidic technology.The Darcy–Weisbach equation combined with computational fluid dynamics modeling was exploited to design the microfluidic chip,and the FSS distribution on the cell model with varying micro-channels(triangular,conical,and elliptical).The diffusion with the incompressible laminar flow model by solving the time-dependent diffusion–convection equation was applied to simulate the gradient profiles of concentration in the micro-channels.For the study of single cell in-depth,the FSS was investigated by the usage of polystyrene particles and the concentration diffusion distribution was studied by the usage of different colors of dyes.A successful agreement between model simulations and experimental data was obtained.Finally,based on the established method,the communication between individual cells was envisaged and modeled.The developed method provides valuable insights and allows to continuously improve the design of microfluidic devices for the study of single cell,the occurrence and development of tumors,and therapeutic applications.展开更多
Bone remodeling is performed under the joint action of osteoblasts and osteoclasts. Since the effect of osteoclasts has been gradually recognized on bone and joint diseases, targeted researches toward osteoclasts have...Bone remodeling is performed under the joint action of osteoblasts and osteoclasts. Since the effect of osteoclasts has been gradually recognized on bone and joint diseases, targeted researches toward osteoclasts have become a hot research field. This article reviews the relevant medical literature concerning the possible effects of the fluid shear stress (FSS) on the osteoclastogenesis chiefly from the aspects of RANKL-RANK-OPG system, the macrophage colony-stimulating factor (M-CSF), and calcitonin receptor (CTR). On the basis of the changes of the expression of osteoclastic activities, it is suggested that FSS is a potent, important regulator of bone metabolism.展开更多
Background:Biopalladium(bioPd(0))nanoparticles on Klebsiella Pneumoniae ECU-15 were synthesized mainly on the microorganism's surface.Data suggest that the resistance of mass transfer around the cell surface regio...Background:Biopalladium(bioPd(0))nanoparticles on Klebsiella Pneumoniae ECU-15 were synthesized mainly on the microorganism's surface.Data suggest that the resistance of mass transfer around the cell surface region plays a critical role in bioPd(0)synthesis process.However,the mechanisms for its role remains elusive.Results:The experimental results indicated that 1)diffusion resistance existed around the microorganism's cell in reaction vessel and 2)fluid shear stress affected the mass transfer rates differently according to its strength and thus had varying effects on the bioPd(0)synthesis.More than 97.9±1.5%Chromium(VI)(Cr(VI))(384μM)was reduced to Cr(III)within 20 min with 5%Pd/bioPd(0)as catalyst,which was generated by the K.Pneumoniae ECU-15,and the catalytic performance of Pd/bioPd(0)was stable over 6 months.The optimal condition of bioreduction of Pd(II)to Pd(0)was determined at the Kolmogorov eddy length of 7.33±0.5μm and lasted for 1 h in the extended reduction process after the usual adsorption and reduction process.Conclusions:It is concluded that a high bioPd(0)catalytic activity can be achieved by controlling the fluid shear stress intensity in an extended reduction process in the bioreactor.展开更多
Objective Epithelial mesenchymal transition(EMT)plays a very important role in ovarian cancer metastasis,and IL-8 released from mechanosensitive cancer cells may contribute to the EMT process of solid carcinomas.In th...Objective Epithelial mesenchymal transition(EMT)plays a very important role in ovarian cancer metastasis,and IL-8 released from mechanosensitive cancer cells may contribute to the EMT process of solid carcinomas.In this study,we have explored IL-8 and its receptors signal transduction process of human ovarian cancer cells under conditions of FSS,and simultaneously detected the EMT process of ovarian cancer.Methods After the fluid shear stress was loaded,LightCyclerTM system and ELISA were employed to assay the IL-8 mRNA expression and protein production,respectively.Meanwhile,IL-8 reporter gene pEGFP1-IL8USCS was constructed for determining IL-8 gene transcriptional activation through gene transfer and flow cytometric analysis.RT-PCR,Northern blot and immunofluorescence were used to determine the expression of IL-8 receptor CXCR2 at mRNA and protein levels.IL-8 downstream signaling molecule NF-κB nuclear translocation was observed by immunocytofluoresent staining.Western blot was used to examine IκB phosphorylation and EMT-related protein.Results(1)The increase of IL-8 mRNA expression by shear stress was time-dependent.The expression increased when SKOV3 cells exposed to fluid shear stress for 1 h,reached the summits at 2 h,gradually decreased at 3 h and remained at a constant level at 4~12 h.Additionally,IL-8 expression was negatively associated with the intensity of shear stress.After SKOV3 cells were exposed to low fluid shear stress(1.5 dyne/cm2)for 1 h and 2 h,IL-8 mRNA expression increased near 68 and 52 times respectively as that of SKOV3 cells exposed to a high fluid shear stress of 5.0 dyne/cm^2.(2)The productions of IL-8 protein in SKOV3 cells subjected to shear stress were time-dependent.The secretion reached the summit when SKOV3 cells exposed to fluid shear stress for 5 h,then IL-8 secretion gradually decreased at 8 h of stimulation by shear stress.IL-8 secretion increased obviously when fluid shear stress(0.5,1.5,or 2.0 dyne/cm2)was exerted on SKOV3 cells for 1 h.Notablely,the secretion of IL-8 was the highest when SKOV3 cells subjected to fluid shear stress 1.5dyne/cm^2,which was near 6 or 7 times as that of SKOV3 cells subjected to high fluid shear stress(5.0 dyne/cm^2).(3)There was an increase in enhanced green fluorescent protein expression in pEGFPI-IL8USCS-transfected SKOV3 cells subjected to a fluid shear stress of 1.5 dyne/cm2 for 2 h,suggesting a flow shear stress induced IL-8 gene transcriptional activation;(4)CXCR2,which was constitutively present on the surface of SKOV3 cells,increased following exposure to fluid shear stress for 60 min.(5)Following the application of a shear stress of 1.5 dyne/cm^2,NF-κB p65 became detectable in the cell nuclei and Phosphorylated IκB in cell lysates increased significantly;(6)Compared with the control group,critical EMT-related proteins vimentin was upregulated,E-cadherin was downregulated after the application of the 1.5 dyne/cm2shear stress for 2 h,which suggested the EMT of ovarian cancer.Conclusions FSS triggered IL-8/CXCR2 signaling of SK-OV3 cells represents an early gene activation and the activation can be mediated through NF-κB.When the fluid shear stress-induced IL-8/CXCR signaling activated,the expression of EMT-related proteins changed.This observation suggested that fluid shear stress-induced IL-8 activation and the downstream signal pathways may have important contribution to the EMT process of ovarian cancer cells.展开更多
The discovery of Piezo channels has advanced the understanding of mechanobiology,which acts as mechanosensitive cation channels in sensing mechanical stimuli and regulating various physiological functions.Despite the ...The discovery of Piezo channels has advanced the understanding of mechanobiology,which acts as mechanosensitive cation channels in sensing mechanical stimuli and regulating various physiological functions.Despite the electrophysiological current recording,localized Piezo activation measurement in cells still faces challenges.In this study,we developed a Piezo1-Ca^(2+)biosensor based on Förster Resonance Energy Transfer(FRET)technology by fusing a calcium-sensing module closely to the channel pores,hence to dynamically detect Piezo1 activation.The biosensor expressed in 293T cells showed~120%FRET change to the specific chemical agonist Yoda1,whose response to Piezo1 activation was evaluated with its key-point mutation(L1342G/L1345G).By comparing cytoplasmic and Lyn-tagged membrane calcium biosensors,Piezo1-Ca^(2+)FRET biosensor primarily reflects localized calcium signals near the plasma membrane.Furthermore,by combining Piezo1-Ca^(2+)FRET imaging with varying microfluidic shear conditions,the biosensor exhibited significant yet transient responses to shear stress(~70%FRET change at 2.8 dyn/cm^(2)),with a threshold of effective activation around 1.0 dyn/cm^(2)(i.e.,10μN/cm^(2)).In conclusion,the developed Piezo1-Ca^(2+)FRET biosensor demonstrated Piezo1 activation by chemical agonist and shear force,which provides an imaging tool with improved spatiotemporal resolution for elucidating the mechanosensitivity of Piezo1 channels.The local specificity for Piezo1-Ca^(2+)signal detection by the biosensor requires individual interpretations under different scenarios.展开更多
Inspired by the thermal stability mechanism of thermophilic protein,which presents ionic bonds that have better stability at higher temperatures,this paper proposes the introduction of electrostatic interactions by ad...Inspired by the thermal stability mechanism of thermophilic protein,which presents ionic bonds that have better stability at higher temperatures,this paper proposes the introduction of electrostatic interactions by adding carboxyl-modified silica(C-SiO2),PAA,and CaCl_(2) to achieve higher viscosity over 25℃.The rheological behavior of C-SiO_(2)-based shear thickening fluid(CS-STF)was investigated at a temperature range of 25–55℃.Unlike SiO_(2)-based STF,which exhibits single-step thickening and a negative correlation between viscosity and temperature.As the C-SiO_(2) content was 41%(w/w)and the mass ratio of PAA:CaCl_(2):C-SiO_(2) was 3:1:10,the CS-STF displayed a double-thickening behavior,and the peak viscosity reached 1330 Pa·s at 35℃.From the yarn pull-out test,the inter-yarn force was significantly increased with the increasing CS-STF content.Treating UHMWPE fabrics with CS-STF improved the impact resistance effectively.In the blunt impact test,the U-CS fabrics with high CS-STF content(121.45 wt%)experienced penetration failure under high impact energy(18 J)due to stress concentration caused by the shear thickening behavior.The knife stabbing test demonstrated that U-CS fabrics with appropriate content(88.38 wt%)have the best stabbing resistance in various impact energies.Overall,this study proposed a high-performence STF showing double-thickening and enhancing shear-thickening behavior at a wide temperature range,the composite fabrics with the performance of resisting both the blunt and stab impact had broad application prospects in the field of personal protection.展开更多
Shear thickening fluids （STFs） based on additives with different concentrations and molecular chain lengths were investigated. STF samples were prepared with silica and additive dispersed in polyethylene glycol （PE...Shear thickening fluids （STFs） based on additives with different concentrations and molecular chain lengths were investigated. STF samples were prepared with silica and additive dispersed in polyethylene glycol （PEG） 400, where three types of additives with different molecular chain lengths of PEG4000, PEG6000, and PEG10000 were used. For PEG10000, different concentrations, including 0, 1%, 3%, and 5%, were selected to study the influences of additive concentrations. Rheological properties of the samples were measured with a rheometer. The results show that the shear thickening effect was significantly enhanced with the increase of the concentration and the molecular chain length of additives. The mechanism of enhancement was quantitatively explained with the formation of large particles clusters.展开更多
The current design of hydro-viscous clutch（HVC） in tracked vehicle fan transmission mainly focuses on high-speed and high power. However, the fluid torque under the influence of fluid temperature can not be predicte...The current design of hydro-viscous clutch（HVC） in tracked vehicle fan transmission mainly focuses on high-speed and high power. However, the fluid torque under the influence of fluid temperature can not be predicted accurately by conventional mathematical model or experimental research. In order to validate the fluid torque of HVC by taking the viscosity-temperature characteristic of fluid into account, the test rig is designed. The outlet oil temperature is measured and fitted with different rotation speed, oil film thickness, oil flow rate, and inlet oil temperature. Meanwhile, the film torque can be obtained. Based on Navier-Stokes equations and the continuity equation, the mathematical model of fluid torque is proposed in cylindrical coordinate. Iterative method is employed to solve the equations. The radial and tangential speed distribution, radial pressure distribution and theoretical flow rate are determined and analyzed. The models of equivalent radius and fluid torque of friction pairs are introduced. The experimental and theoretical results indicate that tangential speed distribution is mainly determined by the relative rotating speed between the friction plate and the separator disc. However, the radial speed distribution and pressure distribution are dominated by pressure difference at the lower rotating speed. The oil film fills the clearance and the film torque increases with increasing rotating speed. However, when the speed reaches a certain value, the centrifugal force will play an important role on the fluid distribution. The pressure is negative at the outer radius when inlet flow rate is less than theoretical flow, so the film starts to shrink which decreases the film torque sharply. The theoretical fluid torque has good agreement with the experimental data. This research proposes a new fluid torque mathematical model which may predict the film torque under the influence of temperature more accurately.展开更多
The behavior of single bubble rising in quiescent shear-thinning tlmds was lnvestlgateO numerically by level set metnoa. number of bubbles in a large range of Reynolds number and Eotvos number were investigated includ...The behavior of single bubble rising in quiescent shear-thinning tlmds was lnvestlgateO numerically by level set metnoa. number of bubbles in a large range of Reynolds number and Eotvos number were investigated including spherical, oblate and spherical. The bubble shape and drag coefficient were compared with experimental results. It is observed that the simulated results show good conformity to experimental results over a wide range of Reynolds number. In addition, the detailed flow field based on the reference coordinate system moving with the bubble is obtained, and the relationship among flow field, bubble shape and velocity is discussed.展开更多
The present study aims at assessing the ballistic impact behaviour of jute reinforced polyethylene glycol(PEG)and nano silica based shear thickening fluid(STF).Preparation of STF is achieved by dispersing the nano sil...The present study aims at assessing the ballistic impact behaviour of jute reinforced polyethylene glycol(PEG)and nano silica based shear thickening fluid(STF).Preparation of STF is achieved by dispersing the nano silica particles at different weight percentage loadings of 10%,20%,30%and 40%in PEG and the effect of various weight percentages loading of nano silica particles on ballistic performance of the proposed composites is studied experimentally.Rheological studies of the prepared STF’s showed that at all nanosilica loading shear thickening occurred and also the shear thickening was highest at higher loading of nano silica at lower rate of shear.The study reveals that the ballistic performance of the jute fabric is enhanced with impregnation of STF.The ballistic results indicate that energy absorption of the proposed composites is enhanced with increased loading of nano silica particles and at the same time,the effect of STF was reduced.Specific energy absorption(SEA)of the neat fabric and the proposed composites was made use of for the purpose of comparing the energy absorption capabilities.It is found that the SEA of proposed composites with 10%nano silica loading is lesser than the neat fabric both in case of 3 layers and 6 layers.It was also found that proposed composite with 40%nano silica loading exhibits highest SEA compared to neat fabric and its counterparts with its SEA being 3.21 and 3.76 times highest compared to three and six layers of neat fabrics respectively.展开更多
In this study,the effects of surfactants on the hydrodynamic characteristics of bubbles in shear-thinning fluids at low Reynolds number(Re<50)are investigated.The bubble terminal velocity and drag coefficient of bu...In this study,the effects of surfactants on the hydrodynamic characteristics of bubbles in shear-thinning fluids at low Reynolds number(Re<50)are investigated.The bubble terminal velocity and drag coefficient of bubble in clean and contaminated carboxymethylcellulose(CMC)solutions are obtained using a high-speed camera for examining differences.The results show that the existence of surfactant could reduce the terminal velocity of bubble at small volume(0.25wt%CMC:<100 mm3;0.50wt%CMC:<110 mm3),attributed to stiffening the bubble interface.However,this negative effect decreases and finally disappears with increasing bubble volume.The drag coefficient curves of the bubble in contaminated CMC solution exhibit behavior similar to that exhibited by a solid sphere at Re<10,indicating that internal circulation flow is absent at the bubble interface as compared to that in clean CMC solution.However,for 10<Re<40,a transition of drag curve from 24/Re to 16/Re in contaminated CMC solution is observed,which is easy at low SDS concentrations and high CMC concentrations.展开更多
Electric vehicles(EVs)have garnered significant attention as a vital driver of economic growth and environmental sustainability.Nevertheless,ensuring the safety of high-energy batteries is now a top priority that cann...Electric vehicles(EVs)have garnered significant attention as a vital driver of economic growth and environmental sustainability.Nevertheless,ensuring the safety of high-energy batteries is now a top priority that cannot be overlooked during large-scale applications.This paper proposes an innovative active protection and cooling integrated battery module using smart materials,magneto-sensitive shear thickening fluid(MSTF),which is specifically designed to address safety threats posed by lithium-ion batteries(LIBs)exposed to harsh mechanical and environmental conditions.The theoretical framework introduces a novel approach for harnessing the smoothed-particle hydrodynamics(SPH)methodology that incorporates the intricate interplay of non-Newtonian fluid behavior,capturing the fluid-structure coupling inherent to the MSTF.This approach is further advanced by adopting an enhanced Herschel-Bulkley(H-B)model to encapsulate the intricate rheology of the MSTF under the influence of the magnetorheological effect(MRE)and shear thickening(ST)behavior.Numerical simulation results show that in the case of cooling,the MSTF is an effective cooling medium for rapidly reducing the temperature.In terms of mechanical abuse,the MSTF solidifies through actively applying the magnetic field during mechanical compression and impact within the battery module,resulting in 66%and 61.7%reductions in the maximum stress within the battery jellyroll,and 31.1%and 23%reductions in the reaction force,respectively.This mechanism effectively lowers the risk of short-circuit failure.The groundbreaking concepts unveiled in this paper for active protection battery modules are anticipated to be a valuable technological breakthrough in the areas of EV safety and lightweight/integrated design.展开更多
The present experimental study investigates shock wave mitigation capability of potentially new personal protective equipment(PPE) suspension pads made from polyurea and shear thickening fluid(STF).The shock tube test...The present experimental study investigates shock wave mitigation capability of potentially new personal protective equipment(PPE) suspension pads made from polyurea and shear thickening fluid(STF).The shock tube test results show that when placed behind Twaron fabric systems with thickness ranging from 2 mm to 18 mm, the replacement of conventional flexible foam pad with STF and STF-infused foam pads with the same thickness of 20 mm greatly reduces the normalized peak pressure(by about 72% for each pad). However, this benefit is partially offset by a large increase in the normalized impulse(by about78% for the STF pad and 131% for the STF-infused foam pad) which may cause the shock wave mitigation performance of these two pads to become less effective. Interestingly, the use of 4 mm thick polyurea pad can greatly reduce the normalized peak pressure and impulse as well(by about 74% and 49%, respectively). These results reveal that among the potentially new suspension pads tested, the polyurea pad displays the best shock wave mitigation performance. Therefore, polyurea has potential for use as a suspension pad in personal protective equipment requiring shock wave mitigation capability such as fabric ballistic vests, bomb suits and combat helmets.展开更多
The hydraulic fracturing is still an effective technology for the exploitation of coalbed methane （CBM）. However, after the hydraulic fracturing operation, the high water cut or sudden water flooding of CBM well usu...The hydraulic fracturing is still an effective technology for the exploitation of coalbed methane （CBM）. However, after the hydraulic fracturing operation, the high water cut or sudden water flooding of CBM well usually occurs due to upward migration of bottom water, which is called water channeling （water inrush）. This problem has been severely limiting the hydraulic fracturing effect of CBM wells. Some studies show that the aquifuge and cement paste themselves will not crush under hydraulic fracturing pressure. Water channeling often occurs at cement- aquifuge interface （CAI）.展开更多
The Suichang mine is the largest silicified vein-type silver-gold mineralization system in Southeast China, whose ore bodies are controlled by shear zones developing in Lower Proterozoic gneiss terrene with initial mi...The Suichang mine is the largest silicified vein-type silver-gold mineralization system in Southeast China, whose ore bodies are controlled by shear zones developing in Lower Proterozoic gneiss terrene with initial migmatization, which is covered by Upper Jurassic and Lower Cretaceous volcanic rock system and cut by acidic igneous veins of Jurassic and Cretaceous. The conclusions are as follows: (1) The ore-forming fluid is defined as superhigh tectonic-metamorphic fluid on the base of : 1 (D)-(18O) values 2 fluid inclusions;3 trace elements of pyrite from ores. (2) The shear zone silicified orebod-ies occurred in proterozoic, Jurassic and Cretaceous, which have been transforms in part by ore-bearing comb quartz vein of volcanism.展开更多
The dynamic analysis of semi-flexible polymers,such as DNA molecules,is an important multiscale problem with a wide range of applications in science and bioengineering.In this contribution,a dumbbell model with intern...The dynamic analysis of semi-flexible polymers,such as DNA molecules,is an important multiscale problem with a wide range of applications in science and bioengineering.In this contribution,a dumbbell model with internal viscosity was studied in steady shear flows of polymeric fluid.The tensors with moments other than second moment were approximated in the terms of second moment tensor.Then,the nonlinear algebraic equation of the second moment conformation tensor was calculated in closed form.Finally,substituting the resulting conformation tensor into the Kramers equation of Hookean spring force,the constitutive equations were obtained.The shear material properties were discussed for different internal viscosities and compared with the results of Brownian dynamics simulation.展开更多
A phenomenological model for dispersed systems which exhibit complex theological behaviour such as shear and time-dependent viscosity, yield stress, and elasticity is proposed. The model extends the Quemeda model to d...A phenomenological model for dispersed systems which exhibit complex theological behaviour such as shear and time-dependent viscosity, yield stress, and elasticity is proposed. The model extends the Quemeda model to describe the viscosity function with a structural parameter λ which varies according to differ- ent kinetic orders of particle aggregation and segregation. The transient stress response is obtained by solving an instantaneous Maxwell model with an assumed shear modulus function G of the same form as the viscosity function η. Accuracy of the proposed model is verified experimentally with the results obtained for two oil (creosote)/water emulsions. The model that gives the best fit of experimental data appears to be the one with kinetic orders n = m = 2.展开更多
Discriminations in a local chemical, fluidal, mechanical and thermal processes in a shear zone will lead to metallogenic differentiation in a local section. This paper, based on the general geological setting of the S...Discriminations in a local chemical, fluidal, mechanical and thermal processes in a shear zone will lead to metallogenic differentiation in a local section. This paper, based on the general geological setting of the Shibangou gold deposit in Xixia, Henan, deals with petrological and petrochemical samples of altered rocks in the metallogenic section and of mylonites in the non\|metallogenic section of a selected shear zone. The discriminations in fluid\|rock interaction and petrological mass balance between altered rocks near the orebody and mylonites in the shear zone are discussed as well. The results show that the petrological volume of altered rocks in the metallogenic section of the shear zone is almost always dilatant and the mylonite volume in the non\|metallogenic section is almost always lost. Major elements in altered rocks from the metallogenic section and in mylonites from the non\|metallogenic section always show a tendency of being enriched and depleted, respectively. Fluid\|rock ratios in the mylonites (Nu=\{93.68-468.40\}) are larger than those of the altered rocks (Nc\+s\-\{(Ⅳ)\}=\{36.11-216.67\}). The gain and loss of major and trace elements from the altered rocks and mylonites in the shear zone are a composite process to be imported and exported by percolating fluids as well as of the loss and dilatancy of rock volume.展开更多
Natural convection flow of unsteady Maxwell fluid with the effects of constant magnetic force in the course of a porous media is investigated in this research work. Fluid motion between a channel of parallel plates is...Natural convection flow of unsteady Maxwell fluid with the effects of constant magnetic force in the course of a porous media is investigated in this research work. Fluid motion between a channel of parallel plates is tempted by time dependent shear stress applied on one plate. The governing partial differential equations of a model under consideration are transformed into ordinary differential equations by Laplace transform method and then solved for temperature and velocity fields. The obtained results for temperature fields are expressed in terms of complementary error function. The influences of involved parameters likes Hartmann number, Grashf number, Prandlt number and porosity parameter, on temperature and velocity profiles are shown graphically. There is no such result regarding Maxwell fluid in the existing literature.展开更多
Using the constitutive equation of co-rotational derivative type for anisotropic viscoelastic fluid-liquid crystalline(LC),polymer liquids was developed.Two relaxation times are introduced in the equation:λn represen...Using the constitutive equation of co-rotational derivative type for anisotropic viscoelastic fluid-liquid crystalline(LC),polymer liquids was developed.Two relaxation times are introduced in the equation:λn represents relaxation of the normal-symmetric stress components;λs represents relaxation of the shear-unsymmetric stress components.A vibrational rotating flow in gap between cylinders with small amplitudes is studied for the anisotropic viscoelastic fluid-liquid crystalline polymer.The time-dependent constitutive equation are linearized with respect to parameter of small amplitude.For the normal-symmetric part of stress tensor analytical expression of the shear stress is obtained by the constitutive equation.The complex viscosity,complex shear modulus,dynamic and imaginary viscosities,storage modulus and loss modulus are obtained for the normal-symmetric stress case which are defined by the common shear rate.For the shear-unsymmetric stress part,two shear stresses are obtained thus two complex viscosities and two complex shear modulus(i.e.first and second one) are given by the constitutive equation which are defined by rotating shear rate introduced by author.The dynamic and imaginary viscosities,storage modulus and loss modulus are given for each complex viscosities and complex shear modulus.Using the constituive equation the rotating flow with small amplitudes in gap between two coaxial cylinders is studied.展开更多
基金National Natural Science Foundation of China(No.21804045)Fujian Provincial Department of Science and Technology(No.2019I0014)Promotion Program for Young and Middle-aged Teachers in Science and Technology Research of Huaqiao University(No.ZQN-PY612)。
文摘Concentration gradient and fluid shear stress(FSS)for cell microenvironment were investigated through microfluidic technology.The Darcy–Weisbach equation combined with computational fluid dynamics modeling was exploited to design the microfluidic chip,and the FSS distribution on the cell model with varying micro-channels(triangular,conical,and elliptical).The diffusion with the incompressible laminar flow model by solving the time-dependent diffusion–convection equation was applied to simulate the gradient profiles of concentration in the micro-channels.For the study of single cell in-depth,the FSS was investigated by the usage of polystyrene particles and the concentration diffusion distribution was studied by the usage of different colors of dyes.A successful agreement between model simulations and experimental data was obtained.Finally,based on the established method,the communication between individual cells was envisaged and modeled.The developed method provides valuable insights and allows to continuously improve the design of microfluidic devices for the study of single cell,the occurrence and development of tumors,and therapeutic applications.
文摘Bone remodeling is performed under the joint action of osteoblasts and osteoclasts. Since the effect of osteoclasts has been gradually recognized on bone and joint diseases, targeted researches toward osteoclasts have become a hot research field. This article reviews the relevant medical literature concerning the possible effects of the fluid shear stress (FSS) on the osteoclastogenesis chiefly from the aspects of RANKL-RANK-OPG system, the macrophage colony-stimulating factor (M-CSF), and calcitonin receptor (CTR). On the basis of the changes of the expression of osteoclastic activities, it is suggested that FSS is a potent, important regulator of bone metabolism.
基金financially supported by the open Project Funding of State Key Laboratory of Bioreactor Engineering of China and the National High Technology Research and Development Program of China(No.2007AA060904 and No.2012AA061503).
文摘Background:Biopalladium(bioPd(0))nanoparticles on Klebsiella Pneumoniae ECU-15 were synthesized mainly on the microorganism's surface.Data suggest that the resistance of mass transfer around the cell surface region plays a critical role in bioPd(0)synthesis process.However,the mechanisms for its role remains elusive.Results:The experimental results indicated that 1)diffusion resistance existed around the microorganism's cell in reaction vessel and 2)fluid shear stress affected the mass transfer rates differently according to its strength and thus had varying effects on the bioPd(0)synthesis.More than 97.9±1.5%Chromium(VI)(Cr(VI))(384μM)was reduced to Cr(III)within 20 min with 5%Pd/bioPd(0)as catalyst,which was generated by the K.Pneumoniae ECU-15,and the catalytic performance of Pd/bioPd(0)was stable over 6 months.The optimal condition of bioreduction of Pd(II)to Pd(0)was determined at the Kolmogorov eddy length of 7.33±0.5μm and lasted for 1 h in the extended reduction process after the usual adsorption and reduction process.Conclusions:It is concluded that a high bioPd(0)catalytic activity can be achieved by controlling the fluid shear stress intensity in an extended reduction process in the bioreactor.
基金supported by Foundation of Sichuan Provincial Science and Technology Program ( 2019YFH0147,2019YFH0158)1. 3. 5 Project for Disciplines of Excellence,West China Hospital,Sichuan University ( ZYJC18016)
文摘Objective Epithelial mesenchymal transition(EMT)plays a very important role in ovarian cancer metastasis,and IL-8 released from mechanosensitive cancer cells may contribute to the EMT process of solid carcinomas.In this study,we have explored IL-8 and its receptors signal transduction process of human ovarian cancer cells under conditions of FSS,and simultaneously detected the EMT process of ovarian cancer.Methods After the fluid shear stress was loaded,LightCyclerTM system and ELISA were employed to assay the IL-8 mRNA expression and protein production,respectively.Meanwhile,IL-8 reporter gene pEGFP1-IL8USCS was constructed for determining IL-8 gene transcriptional activation through gene transfer and flow cytometric analysis.RT-PCR,Northern blot and immunofluorescence were used to determine the expression of IL-8 receptor CXCR2 at mRNA and protein levels.IL-8 downstream signaling molecule NF-κB nuclear translocation was observed by immunocytofluoresent staining.Western blot was used to examine IκB phosphorylation and EMT-related protein.Results(1)The increase of IL-8 mRNA expression by shear stress was time-dependent.The expression increased when SKOV3 cells exposed to fluid shear stress for 1 h,reached the summits at 2 h,gradually decreased at 3 h and remained at a constant level at 4~12 h.Additionally,IL-8 expression was negatively associated with the intensity of shear stress.After SKOV3 cells were exposed to low fluid shear stress(1.5 dyne/cm2)for 1 h and 2 h,IL-8 mRNA expression increased near 68 and 52 times respectively as that of SKOV3 cells exposed to a high fluid shear stress of 5.0 dyne/cm^2.(2)The productions of IL-8 protein in SKOV3 cells subjected to shear stress were time-dependent.The secretion reached the summit when SKOV3 cells exposed to fluid shear stress for 5 h,then IL-8 secretion gradually decreased at 8 h of stimulation by shear stress.IL-8 secretion increased obviously when fluid shear stress(0.5,1.5,or 2.0 dyne/cm2)was exerted on SKOV3 cells for 1 h.Notablely,the secretion of IL-8 was the highest when SKOV3 cells subjected to fluid shear stress 1.5dyne/cm^2,which was near 6 or 7 times as that of SKOV3 cells subjected to high fluid shear stress(5.0 dyne/cm^2).(3)There was an increase in enhanced green fluorescent protein expression in pEGFPI-IL8USCS-transfected SKOV3 cells subjected to a fluid shear stress of 1.5 dyne/cm2 for 2 h,suggesting a flow shear stress induced IL-8 gene transcriptional activation;(4)CXCR2,which was constitutively present on the surface of SKOV3 cells,increased following exposure to fluid shear stress for 60 min.(5)Following the application of a shear stress of 1.5 dyne/cm^2,NF-κB p65 became detectable in the cell nuclei and Phosphorylated IκB in cell lysates increased significantly;(6)Compared with the control group,critical EMT-related proteins vimentin was upregulated,E-cadherin was downregulated after the application of the 1.5 dyne/cm2shear stress for 2 h,which suggested the EMT of ovarian cancer.Conclusions FSS triggered IL-8/CXCR2 signaling of SK-OV3 cells represents an early gene activation and the activation can be mediated through NF-κB.When the fluid shear stress-induced IL-8/CXCR signaling activated,the expression of EMT-related proteins changed.This observation suggested that fluid shear stress-induced IL-8 activation and the downstream signal pathways may have important contribution to the EMT process of ovarian cancer cells.
基金funded by National Natural Science Foundation of China(NSFC 12372312)Project of"iangsu Specially-appointed Professor"(MO)National Natural Science Foundation of China(NSFC 12272063)(LD).
文摘The discovery of Piezo channels has advanced the understanding of mechanobiology,which acts as mechanosensitive cation channels in sensing mechanical stimuli and regulating various physiological functions.Despite the electrophysiological current recording,localized Piezo activation measurement in cells still faces challenges.In this study,we developed a Piezo1-Ca^(2+)biosensor based on Förster Resonance Energy Transfer(FRET)technology by fusing a calcium-sensing module closely to the channel pores,hence to dynamically detect Piezo1 activation.The biosensor expressed in 293T cells showed~120%FRET change to the specific chemical agonist Yoda1,whose response to Piezo1 activation was evaluated with its key-point mutation(L1342G/L1345G).By comparing cytoplasmic and Lyn-tagged membrane calcium biosensors,Piezo1-Ca^(2+)FRET biosensor primarily reflects localized calcium signals near the plasma membrane.Furthermore,by combining Piezo1-Ca^(2+)FRET imaging with varying microfluidic shear conditions,the biosensor exhibited significant yet transient responses to shear stress(~70%FRET change at 2.8 dyn/cm^(2)),with a threshold of effective activation around 1.0 dyn/cm^(2)(i.e.,10μN/cm^(2)).In conclusion,the developed Piezo1-Ca^(2+)FRET biosensor demonstrated Piezo1 activation by chemical agonist and shear force,which provides an imaging tool with improved spatiotemporal resolution for elucidating the mechanosensitivity of Piezo1 channels.The local specificity for Piezo1-Ca^(2+)signal detection by the biosensor requires individual interpretations under different scenarios.
基金the Major Science and Technology Demonstration Projects in Jiangsu Province(Grant No.BE2022608).
文摘Inspired by the thermal stability mechanism of thermophilic protein,which presents ionic bonds that have better stability at higher temperatures,this paper proposes the introduction of electrostatic interactions by adding carboxyl-modified silica(C-SiO2),PAA,and CaCl_(2) to achieve higher viscosity over 25℃.The rheological behavior of C-SiO_(2)-based shear thickening fluid(CS-STF)was investigated at a temperature range of 25–55℃.Unlike SiO_(2)-based STF,which exhibits single-step thickening and a negative correlation between viscosity and temperature.As the C-SiO_(2) content was 41%(w/w)and the mass ratio of PAA:CaCl_(2):C-SiO_(2) was 3:1:10,the CS-STF displayed a double-thickening behavior,and the peak viscosity reached 1330 Pa·s at 35℃.From the yarn pull-out test,the inter-yarn force was significantly increased with the increasing CS-STF content.Treating UHMWPE fabrics with CS-STF improved the impact resistance effectively.In the blunt impact test,the U-CS fabrics with high CS-STF content(121.45 wt%)experienced penetration failure under high impact energy(18 J)due to stress concentration caused by the shear thickening behavior.The knife stabbing test demonstrated that U-CS fabrics with appropriate content(88.38 wt%)have the best stabbing resistance in various impact energies.Overall,this study proposed a high-performence STF showing double-thickening and enhancing shear-thickening behavior at a wide temperature range,the composite fabrics with the performance of resisting both the blunt and stab impact had broad application prospects in the field of personal protection.
文摘Shear thickening fluids （STFs） based on additives with different concentrations and molecular chain lengths were investigated. STF samples were prepared with silica and additive dispersed in polyethylene glycol （PEG） 400, where three types of additives with different molecular chain lengths of PEG4000, PEG6000, and PEG10000 were used. For PEG10000, different concentrations, including 0, 1%, 3%, and 5%, were selected to study the influences of additive concentrations. Rheological properties of the samples were measured with a rheometer. The results show that the shear thickening effect was significantly enhanced with the increase of the concentration and the molecular chain length of additives. The mechanism of enhancement was quantitatively explained with the formation of large particles clusters.
基金supported by National Natural Science Foundation of China(Grant No.51275039)
文摘The current design of hydro-viscous clutch（HVC） in tracked vehicle fan transmission mainly focuses on high-speed and high power. However, the fluid torque under the influence of fluid temperature can not be predicted accurately by conventional mathematical model or experimental research. In order to validate the fluid torque of HVC by taking the viscosity-temperature characteristic of fluid into account, the test rig is designed. The outlet oil temperature is measured and fitted with different rotation speed, oil film thickness, oil flow rate, and inlet oil temperature. Meanwhile, the film torque can be obtained. Based on Navier-Stokes equations and the continuity equation, the mathematical model of fluid torque is proposed in cylindrical coordinate. Iterative method is employed to solve the equations. The radial and tangential speed distribution, radial pressure distribution and theoretical flow rate are determined and analyzed. The models of equivalent radius and fluid torque of friction pairs are introduced. The experimental and theoretical results indicate that tangential speed distribution is mainly determined by the relative rotating speed between the friction plate and the separator disc. However, the radial speed distribution and pressure distribution are dominated by pressure difference at the lower rotating speed. The oil film fills the clearance and the film torque increases with increasing rotating speed. However, when the speed reaches a certain value, the centrifugal force will play an important role on the fluid distribution. The pressure is negative at the outer radius when inlet flow rate is less than theoretical flow, so the film starts to shrink which decreases the film torque sharply. The theoretical fluid torque has good agreement with the experimental data. This research proposes a new fluid torque mathematical model which may predict the film torque under the influence of temperature more accurately.
基金Project(21406141)supported by the National Natural Science Foundation of ChinaProject(20141078)supported by the Scientific Research Starting Foundation for Doctors of Liaoning Province,China+1 种基金Project(L2014060)supported by the Foundation of Department of Education of Liaoning Province,ChinaProject(157B21)supported by the Scientific Research Starting Foundation for Doctors of Shenyang Aerospace University,China
文摘The behavior of single bubble rising in quiescent shear-thinning tlmds was lnvestlgateO numerically by level set metnoa. number of bubbles in a large range of Reynolds number and Eotvos number were investigated including spherical, oblate and spherical. The bubble shape and drag coefficient were compared with experimental results. It is observed that the simulated results show good conformity to experimental results over a wide range of Reynolds number. In addition, the detailed flow field based on the reference coordinate system moving with the bubble is obtained, and the relationship among flow field, bubble shape and velocity is discussed.
文摘The present study aims at assessing the ballistic impact behaviour of jute reinforced polyethylene glycol(PEG)and nano silica based shear thickening fluid(STF).Preparation of STF is achieved by dispersing the nano silica particles at different weight percentage loadings of 10%,20%,30%and 40%in PEG and the effect of various weight percentages loading of nano silica particles on ballistic performance of the proposed composites is studied experimentally.Rheological studies of the prepared STF’s showed that at all nanosilica loading shear thickening occurred and also the shear thickening was highest at higher loading of nano silica at lower rate of shear.The study reveals that the ballistic performance of the jute fabric is enhanced with impregnation of STF.The ballistic results indicate that energy absorption of the proposed composites is enhanced with increased loading of nano silica particles and at the same time,the effect of STF was reduced.Specific energy absorption(SEA)of the neat fabric and the proposed composites was made use of for the purpose of comparing the energy absorption capabilities.It is found that the SEA of proposed composites with 10%nano silica loading is lesser than the neat fabric both in case of 3 layers and 6 layers.It was also found that proposed composite with 40%nano silica loading exhibits highest SEA compared to neat fabric and its counterparts with its SEA being 3.21 and 3.76 times highest compared to three and six layers of neat fabrics respectively.
基金Project(21406141)supported by the National Natural Science Foundation of ChinaProject(20141078)supported by the National Basic Research Program,ChinaProject(L201733)supported by the Research Foundation of Education Bureau of Liaoning Province,China
文摘In this study,the effects of surfactants on the hydrodynamic characteristics of bubbles in shear-thinning fluids at low Reynolds number(Re<50)are investigated.The bubble terminal velocity and drag coefficient of bubble in clean and contaminated carboxymethylcellulose(CMC)solutions are obtained using a high-speed camera for examining differences.The results show that the existence of surfactant could reduce the terminal velocity of bubble at small volume(0.25wt%CMC:<100 mm3;0.50wt%CMC:<110 mm3),attributed to stiffening the bubble interface.However,this negative effect decreases and finally disappears with increasing bubble volume.The drag coefficient curves of the bubble in contaminated CMC solution exhibit behavior similar to that exhibited by a solid sphere at Re<10,indicating that internal circulation flow is absent at the bubble interface as compared to that in clean CMC solution.However,for 10<Re<40,a transition of drag curve from 24/Re to 16/Re in contaminated CMC solution is observed,which is easy at low SDS concentrations and high CMC concentrations.
基金Project supported by the National Natural Science Foundation of China(Nos.12072183 and11872236)the Key Research Project of Zhejiang Laboratory(No.2021PE0AC02)。
文摘Electric vehicles(EVs)have garnered significant attention as a vital driver of economic growth and environmental sustainability.Nevertheless,ensuring the safety of high-energy batteries is now a top priority that cannot be overlooked during large-scale applications.This paper proposes an innovative active protection and cooling integrated battery module using smart materials,magneto-sensitive shear thickening fluid(MSTF),which is specifically designed to address safety threats posed by lithium-ion batteries(LIBs)exposed to harsh mechanical and environmental conditions.The theoretical framework introduces a novel approach for harnessing the smoothed-particle hydrodynamics(SPH)methodology that incorporates the intricate interplay of non-Newtonian fluid behavior,capturing the fluid-structure coupling inherent to the MSTF.This approach is further advanced by adopting an enhanced Herschel-Bulkley(H-B)model to encapsulate the intricate rheology of the MSTF under the influence of the magnetorheological effect(MRE)and shear thickening(ST)behavior.Numerical simulation results show that in the case of cooling,the MSTF is an effective cooling medium for rapidly reducing the temperature.In terms of mechanical abuse,the MSTF solidifies through actively applying the magnetic field during mechanical compression and impact within the battery module,resulting in 66%and 61.7%reductions in the maximum stress within the battery jellyroll,and 31.1%and 23%reductions in the reaction force,respectively.This mechanism effectively lowers the risk of short-circuit failure.The groundbreaking concepts unveiled in this paper for active protection battery modules are anticipated to be a valuable technological breakthrough in the areas of EV safety and lightweight/integrated design.
基金supported by the Ministry of Education,Singapore(R265000533112)
文摘The present experimental study investigates shock wave mitigation capability of potentially new personal protective equipment(PPE) suspension pads made from polyurea and shear thickening fluid(STF).The shock tube test results show that when placed behind Twaron fabric systems with thickness ranging from 2 mm to 18 mm, the replacement of conventional flexible foam pad with STF and STF-infused foam pads with the same thickness of 20 mm greatly reduces the normalized peak pressure(by about 72% for each pad). However, this benefit is partially offset by a large increase in the normalized impulse(by about78% for the STF pad and 131% for the STF-infused foam pad) which may cause the shock wave mitigation performance of these two pads to become less effective. Interestingly, the use of 4 mm thick polyurea pad can greatly reduce the normalized peak pressure and impulse as well(by about 74% and 49%, respectively). These results reveal that among the potentially new suspension pads tested, the polyurea pad displays the best shock wave mitigation performance. Therefore, polyurea has potential for use as a suspension pad in personal protective equipment requiring shock wave mitigation capability such as fabric ballistic vests, bomb suits and combat helmets.
基金supported by the National Natural Science Foundation of China(grant No.41572142)the National Science and Technology Major Project of China(grant No.2017ZX05009003-003)
文摘The hydraulic fracturing is still an effective technology for the exploitation of coalbed methane （CBM）. However, after the hydraulic fracturing operation, the high water cut or sudden water flooding of CBM well usually occurs due to upward migration of bottom water, which is called water channeling （water inrush）. This problem has been severely limiting the hydraulic fracturing effect of CBM wells. Some studies show that the aquifuge and cement paste themselves will not crush under hydraulic fracturing pressure. Water channeling often occurs at cement- aquifuge interface （CAI）.
基金Chinese Gold Management. Office (No.93-45-33) and Zhejiag Metallurgical (No. 98-27).
文摘The Suichang mine is the largest silicified vein-type silver-gold mineralization system in Southeast China, whose ore bodies are controlled by shear zones developing in Lower Proterozoic gneiss terrene with initial migmatization, which is covered by Upper Jurassic and Lower Cretaceous volcanic rock system and cut by acidic igneous veins of Jurassic and Cretaceous. The conclusions are as follows: (1) The ore-forming fluid is defined as superhigh tectonic-metamorphic fluid on the base of : 1 (D)-(18O) values 2 fluid inclusions;3 trace elements of pyrite from ores. (2) The shear zone silicified orebod-ies occurred in proterozoic, Jurassic and Cretaceous, which have been transforms in part by ore-bearing comb quartz vein of volcanism.
基金Project(10702045) supported by the National Natural Science Foundation of China
文摘The dynamic analysis of semi-flexible polymers,such as DNA molecules,is an important multiscale problem with a wide range of applications in science and bioengineering.In this contribution,a dumbbell model with internal viscosity was studied in steady shear flows of polymeric fluid.The tensors with moments other than second moment were approximated in the terms of second moment tensor.Then,the nonlinear algebraic equation of the second moment conformation tensor was calculated in closed form.Finally,substituting the resulting conformation tensor into the Kramers equation of Hookean spring force,the constitutive equations were obtained.The shear material properties were discussed for different internal viscosities and compared with the results of Brownian dynamics simulation.
文摘A phenomenological model for dispersed systems which exhibit complex theological behaviour such as shear and time-dependent viscosity, yield stress, and elasticity is proposed. The model extends the Quemeda model to describe the viscosity function with a structural parameter λ which varies according to differ- ent kinetic orders of particle aggregation and segregation. The transient stress response is obtained by solving an instantaneous Maxwell model with an assumed shear modulus function G of the same form as the viscosity function η. Accuracy of the proposed model is verified experimentally with the results obtained for two oil (creosote)/water emulsions. The model that gives the best fit of experimental data appears to be the one with kinetic orders n = m = 2.
文摘Discriminations in a local chemical, fluidal, mechanical and thermal processes in a shear zone will lead to metallogenic differentiation in a local section. This paper, based on the general geological setting of the Shibangou gold deposit in Xixia, Henan, deals with petrological and petrochemical samples of altered rocks in the metallogenic section and of mylonites in the non\|metallogenic section of a selected shear zone. The discriminations in fluid\|rock interaction and petrological mass balance between altered rocks near the orebody and mylonites in the shear zone are discussed as well. The results show that the petrological volume of altered rocks in the metallogenic section of the shear zone is almost always dilatant and the mylonite volume in the non\|metallogenic section is almost always lost. Major elements in altered rocks from the metallogenic section and in mylonites from the non\|metallogenic section always show a tendency of being enriched and depleted, respectively. Fluid\|rock ratios in the mylonites (Nu=\{93.68-468.40\}) are larger than those of the altered rocks (Nc\+s\-\{(Ⅳ)\}=\{36.11-216.67\}). The gain and loss of major and trace elements from the altered rocks and mylonites in the shear zone are a composite process to be imported and exported by percolating fluids as well as of the loss and dilatancy of rock volume.
文摘Natural convection flow of unsteady Maxwell fluid with the effects of constant magnetic force in the course of a porous media is investigated in this research work. Fluid motion between a channel of parallel plates is tempted by time dependent shear stress applied on one plate. The governing partial differential equations of a model under consideration are transformed into ordinary differential equations by Laplace transform method and then solved for temperature and velocity fields. The obtained results for temperature fields are expressed in terms of complementary error function. The influences of involved parameters likes Hartmann number, Grashf number, Prandlt number and porosity parameter, on temperature and velocity profiles are shown graphically. There is no such result regarding Maxwell fluid in the existing literature.
基金Project(10772177) supported by the National Natural Science Foundation of China
文摘Using the constitutive equation of co-rotational derivative type for anisotropic viscoelastic fluid-liquid crystalline(LC),polymer liquids was developed.Two relaxation times are introduced in the equation:λn represents relaxation of the normal-symmetric stress components;λs represents relaxation of the shear-unsymmetric stress components.A vibrational rotating flow in gap between cylinders with small amplitudes is studied for the anisotropic viscoelastic fluid-liquid crystalline polymer.The time-dependent constitutive equation are linearized with respect to parameter of small amplitude.For the normal-symmetric part of stress tensor analytical expression of the shear stress is obtained by the constitutive equation.The complex viscosity,complex shear modulus,dynamic and imaginary viscosities,storage modulus and loss modulus are obtained for the normal-symmetric stress case which are defined by the common shear rate.For the shear-unsymmetric stress part,two shear stresses are obtained thus two complex viscosities and two complex shear modulus(i.e.first and second one) are given by the constitutive equation which are defined by rotating shear rate introduced by author.The dynamic and imaginary viscosities,storage modulus and loss modulus are given for each complex viscosities and complex shear modulus.Using the constituive equation the rotating flow with small amplitudes in gap between two coaxial cylinders is studied.
