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heat transfer attributes of Al_(2)O_(3)-Fe_(3)O_(4)/h_(2)O hybrid nanofluid flow over a yawed cylinder

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Propulsion and Power Research 2022年第3期11卷 416-429页

作者： P.M.Patil h.F.Shankar Department of Mathematics KLE Technological UniversityB V Bhoomaraddi CampusVidyanagarHubballi-580031India Department of Mathematics Karnatak UniversityPavate NagarDharawad-580003India

Flow over yawed and unyawed blunt bodies often occurs in various engineeringapplications. The fluid flow over a yawed cylinder explains the practical significance of subseaapplications such as transference control, separating the boundary layer above submergedblocks, and suppressing recirculating bubbles. The current study uses viscous dissipation toanalyze the mixed convective hybrid nanofluid flow around a yawed cylinder. Unlike the stan-dard nanofluid model, which only considers one type of nanoparticle, this work considers thehybridization of two types of nanoparticles: alumina (Al_(2)O_(3)) and magnetite (Fe_(3)O_(4)). A modelwas developed to investigate the heat transport behaviour of a hybrid nanofluid while account-ing for the solid volume fraction. The flow problem is modelled in terms of highly nonlinearpartial differential equations (NPDEs) subject to the appropriate boundary conditions. Thenappropriate non-similar transformations were used to non-dimensionalize the governing equa-tions. Furthermore, the non-dimensional governing equations were solved using the finite dif-ference method (FDM) and the quasilinearisation technique. The effects of water andnanoparticle concentrations on the velocity and the temperature patterns were illustrated graph-ically. The hybrid nanofluid reduces the velocity distribution in the spanwise and chordwise di-rections while increasing the surface drag coefficient. The hybrid nanofluid’s fluid temperatureand energy transport strength was higher than the base fluid and nanofluid. Also, the temper-ature of the fluid rises as the energy transfer strength diminishes due to an increase in the Eckert number, which characterizes viscous dissipation. however, when the yaw angle increases in thechordwise and spanwise directions, so does the fluid’s velocity. The new outcomes werecompared to previously published research and were in good agreement.

关键词： Yawed cylinder Mixed convection hybrid nanofluid Eckert number Finite difference method

Gaussian process hydrodynamics

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Applied Mathematics and Mechanics(English Edition) 2023年第7期44卷 1175-1198页

作者： h.OWhADI California Institute of Technology MC 9-94PasadenaCA 91125U.S.A.

We present a Gaussian process(GP)approach,called Gaussian process hydrodynamics(GPh)for approximating the solution to the Euler and Navier-Stokes(NS)*** to smoothed particle hydrodynamics(SPh),GPh is a Lagrangian particle-based approach that involves the tracking of a finite number of particles transported by a ***,these particles do not represent mollified particles of matter but carry discrete/partial information about the continuous *** is achieved by placing a divergence-free GP priorξon the velocity field and conditioning it on the vorticity at the particle *** physics(e.g.,the Richardson cascade and velocityincrement power laws)is incorporated into the GP prior by using physics-informed additive *** is equivalent to expressingξas a sum of independent GPsξl,which we call modes,acting at different scales(each modeξlself-activates to represent the formation of eddies at the corresponding scales).This approach enables a quantitative analysis of the Richardson cascade through the analysis of the activation of these modes,and enables us to analyze coarse-grain turbulence statistically rather than *** GPh is formulated by using the vorticity equations,it does not require solving a pressure *** enforcing incompressibility and fluid-structure boundary conditions through the selection of a kernel,GPh requires significantly fewer particles than *** GPh has a natural probabilistic interpretation,the numerical results come with uncertainty estimates,enabling their incorporation into an uncertainty quantification(UQ)pipeline and adding/removing particles(quanta of information)in an adapted *** proposed approach is suitable for analysis because it inherits the complexity of state-of-the-art solvers for dense kernel matrices and results in a natural definition of turbulence as information *** experiments support the importance of selecting physics-informed kernels and

关键词： I Navier-Stokes(NS)equation Euler Lagrangian vorticity Gaussian pro-cess(GP) physics-informed kernel

h-M Bearing Capacity of A Modified Suction Caisson Determined by Using Load-/Displacement-Controlled Methods

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China Ocean Engineering 2016年第6期30卷 926-941页

作者：张雨坤高玉峰李大勇 Ali h.Mahfouz Key Laboratory of Ministry of Education for Geomechanies and Embankment Engineering Hohai UniversityNanjing 210098China College of Civil Engineering and Architecture Shandong University of Science and TechnologyQingdao 266590China Faculty of Petroleum and Mining Engineering Suez UniversityIsmailiaEgypt

This paper presents a series of monotonically combined lateral loading tests to investigate the bearing capacity of the MSCs （modified suction caissons） in the saturated marine fine sand. The lateral loads were applied under load- and displacement-controlled methods at the loading eccentricity ratios of 1.5, 2.0 and 2.5. Results show that, in the displacement-controlled test, the deflection-softening behavior of load-deflection curves for MSCs was observed, and the softening degree of the load-deflection response increased with the increasing external skirt length or the decreasing loading eccentricity. It was also found that the rotation center of the MSC at failure determined by the load-controlled method is slightly lower than that by the displacement-controlled method. The calculated MSC capacity based on the rotation center position in serviceability limit state is relatively conservative, compared with the calculated capacity based on the rotation center position in the ultimate limit state. In the limit state, the passive earth pressures opposite the loading direction under load- and displacement-controlled methods decrease by 46% and 74% corresponding to peak values, respectively; however, the passive earth pressures in the loading direction at failure only decrease by approximately 3% and 7%, compared with their peak values.

关键词： MSC (modified suction caisson) saturated marine fine sand model tests load- and displacement-controlled loading laterally combined bearing capacity earth pressure

Microstructure characterization and electrochemical corrosion behavior of Zn and Zn/Mg alloys in h_2SO_4 solution

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Journal of Central South University 2015年第6期22卷 2007-2013页

作者： S.h.Ettefagh Far A.Rahimi M.Chaghazardi A.Davoodi Young Researchers and Elites Club North Tehran Branch Islamic Azad University Electrochemistry and Inhibitors Group Environmental Protection DepartmentResearch Institute of Petroleum Industry Materials and Polymers Engineering Department Faculty of Engineering Hakim Sabzevari University

The three systems of pure Zn, Zn-0.10% Mg(mass fraction), and Zn-0.15% Mg(mass fraction) were cast under controlled atmosphere and their microstructures were characterized by SEM/EDS analysis. The electrochemical corrosion behavior of these three samples was examined in the very aggressive solution of 50% h2SO4(mass fraction) using electrochemical impedance spectroscopy(EIS) and potentiodynamic polarization measurements. The results show that magnesium improves in some extent the corrosion resistance of pure Zn in 50% h2SO4(mass fraction) confirmed by EIS test. Results of polarization measurment also demonstrate that small amount of Mg significantly improves the passivation of Zn in the test solution. Results of surface morphology of the samples and EDS analysis reveal that Mg reduced the corrosion attacks to pure Zn.

关键词： composites corrosion zinc-magnesium alloys potentiodynamic polarization electrochemical impedance spectroscopy

A Perturbation of Jensen *-Derivations from K(h)into K(h)

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Analysis in Theory and Applications 2016年第4期32卷 333-338页

作者： h.Reisi Department of Mathematics Semnan University

Let＇s take h as an infinite-dimensional hilbert space and K（h） be the set of all compact operators on h. Using Spectral theorem for compact self-adjoint operators, we prove the hyers-Ulam stability of Jensen z-deri... 详细信息

关键词： Jensen *-derivation C^*-algebra hyers-Ulam stability.

The sexually dimorphic expression of glutamate transporters and their implication in pain after spinal cord injury

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Neural Regeneration Research 2025年第11期20卷 3317-3329页

作者： Jennifer M.Colón-Mercado Aranza I.Torrado-Tapias Iris K.Salgado Jose M.Santiago Samuel E.Ocasio Rivera Dina P.Bracho-Rincon Luis h.Pagan Rivera Jorge D.Miranda Department of Physiology University of Puerto RicoMedical Sciences CampusSan JuanPRUSA National Institutes of health National Human Genome Research InstituteBethesdaMDUSA Universidad Central del Caribe School of MedicineBayamónPRUSA University of Puerto Rico Carolina CampusCarolinaPRUSA Institute of Neurobiology San JuanPRUSA

In addition to the loss of motor function,~60% of patients develop pain after spinal cord *** cellular-molecular mechanisms are not well understood,but the data suggests that plasticity within the rostral,epicenter,and caudal penumbra of the injury site initiates a cellularmolecular interplay that acts as a rewiring mechanism leading to central neuropathic *** can lead to the formation of new connections triggering abnormal sensory *** excitatory glutamate transporters are responsible for the reuptake of extracellular glutamate which makes them a critical target to prevent neuronal hyperexcitability and *** previous studies showed a sexually dimorphic therapeutic window for spinal cord injury after treatment with the selective estrogen receptor modulator *** this study,we investigated the anti-allodynic effects of tamoxifen in male and female rats with spinal cord *** hypothesized that tamoxifen exerts anti-allodynic effects by increasing the expression of glutamate transporters,leading to reduced hyperexcitability of the secondary neuron or by decreasing aberrant *** and female rats received a moderate contusion to the thoracic spinal cord followed by subcutaneous slow-release treatment of tamoxifen or matrix pellets as a control(placebo).We used von Frey monofilaments and the“up-down method”to evaluate mechanical *** treatment decreased allodynia only in female rats with spinal cord injury revealing a sexdependent *** expression profile of glutamatergic transporters(excitatory amino acid transporter 1/glutamate aspartate transporter and excitatory amino acid transporter 2/glutamate transporter-1)revealed a sexual dimorphism in the rostral,epicenter,and caudal areas of the spinal cord with a pattern of expression primarily on *** rodents showed a significantly higher level of excitatory amino acid transporter-1 expression while male rodents showed increased

关键词： allodynia central neuropathic pain EAAT-1/GLAST EAAT-2/GLT-1 glutamate transporters selective estrogen receptor modulator sexual dimorphism spinal cord injury trauma

Systems engineering optimization of Omid-2 in the conceptual design phase

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Journal of Systems Engineering and Electronics 2016年第3期27卷 634-648页

作者： h.Shahrabi Seid h.Pourtakdoust Department of Mechanical and Aerospace Engineering Science and Research BranchIslamic Azad University

Due to the importance and role of systems engineering in space mission developments, optimization of Omid＇s systems engineering as a milestone to its current and future generations is focused. In this regard systems engineering management organization as the basis of optimization work flow in the conceptual design phase is proposed for improvement. To improve the systems engineering management, an agile enhanced organization chart is developed that defines various system duties. This is a type of concurrent engineering approach that promotes direct communication and data interchange between the team members. Due to the importance of decision making in the conceptual design phase, two design matrices are constructed that portray merits of various design options in terms of improved satellite life as well as specific choices of remote sensing capability for the Omid second generation（Omid-2）. Conceptual design optimization is explored considering several structural objectives as well as optimal solar energy absorption utilizing a multiple criteria decision making approach. The Eigenvector method is utilized to formulate the objective function via expert judgment. This approach is robust with respect to designer probable miss-judgment. The optimized version of Omid-2 turned out to be a passive Z-axis spin stabilized satellite made of hexagonal honeycomb configuration with carbon-epoxy side panels and Aluminum bottom plate.

关键词： Omid satellite systems engineering optimization conceptual design

Influence of stretch and temperature on the energy density of dielectric elastomer generators

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Applied Mathematics and Mechanics(English Edition) 2019年第11期40卷 1547-1560页

作者： h.KhAJEhSAEID h.BAGhShOMAL AZAR School of Engineering-Emerging Technologies University of Tabriz

Application of dielectric elastomers (DE) has remarkably increased in mechatronics because they are suitable candidates for energy harvesting due to their low cost,light weight,and high energy *** dielectric elastomer generators (DEGs) exhibit high performance regardless of the applications ***,functioning as a generator,a DE may lose its efficiency due to several failure modes including material rupture,loss of tension (LT),electrical breakdown (EB),and electromechanical instability (EMI).The failure modes confine the area of allowable states for generation *** constant and dielectric strength of such elastomers depend on the amount of applied deformation and also working temperature,which are often ignored in theoretical *** this paper,variations of the above-mentioned parameters are considered in mechanical and electrical modellings to investigate their effects on energy density and efficiency of *** results show that,ignoring the variations of material dielectric constant and dielectric strength leads to overestimation of the specific ***,it is shown that,for an acrylic-based generator,the specific energy sharply decreases with temperature rise.

关键词： renewable energy dielectric elastomer generator (DEG) stretch temperature

Free vibration and buckling analysis of polymeric composite beams reinforced by functionally graded bamboo fbers

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Applied Mathematics and Mechanics(English Edition) 2024年第3期45卷 543-562页

作者： h.M.FEIZABAD M.h.YAS Department of Mechanical Engineering Razi UniversityKermanshah ***Iran

Natural fibers have been extensively researched as reinforcement materials in polymers on account of their environmental and economic advantages in comparison with synthetic fibers in the recent *** fibers are renowned for their good mechanical properties,abundance,and short cycle *** beams are one of the fundamental structural components and are susceptible to mechanical loads in engineering applications,this paper performs a study on the free vibration and buckling responses of bamboo fiber reinforced composite(BFRC)beams on the elastic *** different functionally graded(FG)layouts and a uniform one are the considered distributions for unidirectional long bamboo fibers across the *** elastic properties of the composite are determined with the law of *** hamilton’s principle,the governing equations of motion are *** generalized differential quadrature method(GDQM)is then applied to the equations to obtain the *** achieved outcomes exhibit that the natural frequency and buckling load values vary as the fiber volume fractions and distributions,elastic foundation stiffness values,and boundary conditions(BCs)and slenderness ratio of the beam ***,a comparative study is conducted between the derived analysis outcomes for BFRC and homogenous polymer beams to examine the effectiveness of bamboo fibers as reinforcement materials,demonstrating the significant enhancements in both vibration and buckling responses,with the exception of natural frequencies for cantilever beams on the Pasternak foundation with the FG-◇fiber ***,the obtained analysis results of BFRC beams are also compared with those for carbon nanotube reinforced composite(CNTRC)beams found in the literature,indicating that the buckling loads and natural frequencies of BFRC beams are lower than those of CNTRC beams.

关键词： bamboo fiber free vibration buckling analysis functionally graded(FG)beam elastic foundation generalized differential quadrature method(GDQM)