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Transport mechanism in chemically reactive hybrid nanofluid flow containing gyrotactic micro-organisms over a curved oscillatory surface

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Applied Mathematics and Mechanics(English Edition) 2025年第01期 177-192页

作者： M.NAVEED M.imran T.ASGHAR z.ABBAS Department of Mathematics Division of Science and TechnologyUniversity of Education Department of Mathematics The Islamia University of Bahawalpur

This paper examines the transport analysis, including both heat transfer and mass transfer, in hybrid nanofluid flow containing gyrotactic microorganisms towards a curved oscillatory surface. The influence of magnetic fields is also inspected in terms of their physical characteristics. To depict the phenomena of transport, modified versions of both Fick's and Fourier's laws are used. Additionally, the characteristics of both heterogeneous and homogeneous chemical reactions are also incorporated. Utiliz.ng a curvilinear coordinate system, the flow problem is formulated as partial differential equations(PDEs)for momentum, concentration, microorganism field, and energy. An analytical solution to the obtained flow equations is achieved utiliz.ng the homotopy analysis method(HAM).The effects of significant flow parameters on the pressure and microorganism fields, velocity, oscillation velocity, concentration, and temperature distributions are shown via graphs. Furthermore, the variations in skin friction, mass transfer rate, heat transfer rate, and local motile number due to different involved parameters are presented in tables and are analyz.d in detail. Graphical results indicate that the curves of velocity and temperature fields are enhanced as the values of the solid volume fraction variables *** is also verified that the concentration rate field decreases as the values of the homogeneous reaction strength parameter and the radius of curvature parameter increase, and it increases with the Schmidt number and the heterogeneous reaction strength *** outcomes show a favorable response of the motile number to advanced values of the Peclet number, the Schmidt number, the microorganism difference parameter, and the bio-convective Lewis number.

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ON THE L_∞ CONVERGENCE AND THE EXTRAPOLATION METHOD OF A DIFFERENCE SCHEME FOR NONLOCAL PARABOLIC EQUATION WITH NATURAL BOUNDARY CONDITIONS

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Journal of Computational Mathematics 2001年第5期19卷 449-458页

作者： Wan, z.-S. Sun, z.-z. Institute of Applied Physics and CM P.O. Box 8009 Beijing 100088 China

In paper (J. Comput. Appl. Math., 76 (1996), 137-146), a difference scheme for a class of nonlocal parabolic equations with natural boundary conditions was derived by the method of reduction of order and the unique solvability and second order convergence in L2-norm are proved. In this paper, we prove that the scheme is second order convergent in L∞ norm and then obtain fourth order accuracy approximation in L∞ norm by extrapolation method. At last, one numerical example is presented.

关键词： Approximation theory Boundary conditions Convergence of numerical methods Extrapolation

Targeting epigenetic mechanisms in amyloid-β-mediated Alz.eimer’s pathophysiology:unveiling therapeutic potential

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Neural Regeneration Research 2025年第1期20卷 54-66页

作者： Jennie z.Li Nagendran Ramalingam Shaomin Li Ann Romney Center for Neurologic Diseases Brigham and Women’s Hospital and Harvard Medical SchoolBostonMAUSA

Alz.eimer’s disease is a prominent chronic neurodegenerative condition characteriz.d by a gradual decline in memory leading to *** evidence suggests that Alz.eimer’s disease is associated with accumulating various amyloid-βoligomers in the brain,influenced by complex genetic and environmental *** memory and cognitive deficits observed during the prodromal and mild cognitive impairment phases of Alz.eimer’s disease are believed to primarily result from synaptic *** life,environmental factors can lead to enduring changes in gene expression and the emergence of brain *** changes,known as epigenetic modifications,also play a crucial role in regulating the formation of synapses and their adaptability in response to neuronal *** this context,we highlight recent advances in understanding the roles played by key components of the epigenetic machinery,specifically DNA methylation,histone modification,and microRNAs,in the development of Alz.eimer’s disease,synaptic function,and activity-dependent synaptic ***,we explore various strategies,including enriched environments,exposure to non-invasive brain stimulation,and the use of pharmacological agents,aimed at improving synaptic function and enhancing long-term potentiation,a process integral to epigenetic ***,we deliberate on the development of effective epigenetic agents and safe therapeutic approaches for managing Alz.eimer’s *** suggest that addressing Alz.eimer’s disease may require distinct tailored epigenetic drugs targeting different disease stages or pathways rather than relying on a single drug.

关键词： Alz.eimer’s disease DNA methylation enriched environments histone modification microRNAs non-invasive brain stimulation synaptic plasticity

Stress analysis near the tips of a transverse crack in an elastic semi-strip

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Applied Mathematics and Mechanics(English Edition) 2017年第7期38卷 935-956页

作者： z. z.URAVLOVA Institute of Mathematics Economics and Mechanics Odessa I. I. Mechnikov National University Odessa 65082 Ukraine

The plane elastic problem for a semi-strip with a transverse crack is inves- tigated. The initial problem is reduced to a one-dimensional continuous problem by use of an integral transformation method with a generaliz.d scheme. The one-dimensional problem is first formulated as a vector boundary problem, and then reduced to a system of three singular integral equations （SIEs）. The system is solved by use of an orthogonal polynomial method and a special generaliz.d method. The contribution of this work is the consideration of kernel fixed singularities in solving the system. The crack length and its location relative to the semi-strip＇s lateral sides are investigated to simplify the problem＇s statement. This simplification reduces the initial problem to a system of two SIEs.

关键词： semi-strip transverse crack Green's function integral transformation,fixed singularity singular integral equation (SIE)

Flow of Eyring-Powell liquid due to oscillatory stretchable curved sheet with modified Fourier and Fick’s model

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Applied Mathematics and Mechanics(English Edition) 2021年第10期42卷 1461-1478页

作者： M.imran z.ABBAS M.NAVEED Department of Mathematics The Islamia University of BahawalpurBahawalpur 63100Pakistan Department of Mathematics Khwaja Fareed University of Engineering&Information TechnologyRahim Yar Khan 64200Pakistan

This study deals with the features of the mass and heat transport mechanism by adopting a modified version of Fourier and Fick’s model known as the CattaneoChristov double diffusive *** time-dependent magnetohydrodynamic(MHD)flow of the Eyring-Powell liquid across an oscillatory stretchable curved sheet in the presence of Fourier and Fick’s model is *** acquired set of flow equations is transformed into the form of nonlinear partial differential equations(PDEs)by applying appropriate similarity variables.A convergent series solution to the developed nonlinear equations is accomplished with the help of an analytical approach,i.e.,the homotopy analysis method(HAM).The consequences of diverse parameters,including the dimensionless EyringPowell liquid parameter,the radius of curvature,the Schmidt/Prandtl numbers,the ratio of the oscillatory frequency of the sheet to its stretchable rate constant,the mass and thermal relaxation variables involved in the flow,and the heat and mass properties,are displayed through graphs and *** is noted from this study that the amplitude of the pressure distribution rises for the high parametric values of the Eyring-Powell parameter.

关键词： oscillatory stretchable curved surface magnetohydrodynamic(MHD) Eyring-Powell liquid Cattaneo-Christov double diffusion analytical technique

Numerical investigation on the flowfield of “swallowtail” cavity for supersonic mixing enhancement

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Acta Mechanica Sinica 2009年第1期25卷 37-44页

作者： C. Wang z. Jiang z. Hu J. Lu Institute or Mechanics. Chinese Academy of Sciences 100190 Beijing China ReCAPT Gyeongsang National University JinjuKyeongnam 660-701 South Korea

A ＂swallowtail＂ cavity for the supersonic combustor was proposed to serve as an efficient flame holder for scramjets by enhancing the mass exchange between the cavity and the main flow. A numerical study on the ＂swallow- tail＂ cavity was conducted by solving the three-dimensional Reynolds-averaged Navier-Stokes equations implemented with a k-e turbulence model in a multi-block mesh. Turbu- lence model and numerical algorithms were validated first, and then test cases were calculated to investigate into the mechanism of cavity flows. Numerical results demonstrated that the certain mass in the supersonic main flow was sucked into the cavity and moved spirally toward the combustor walls. After that, the flow went out of the cavity at its lateral end, and finally was efficiently mixed with the main flow. The comparison between the ＂swallowtail＂ cavity and the conventional one showed that the mass exchanged between the cavity and the main flow was enhanced by the lateral flow that was induced due to the pressure gradient inside the cavity and was driven by the three-dimensional vortex ring generated from the ＂swallowtail＂ cavity structure.

关键词： Supersonic mixing - Flame holder "Swallowtail" cavity - Combustion ignition Numerical simulation

Determination of surface structure and the depth profile of silica glass by infrared spectroscopy

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光学精密工程 2005年第4期13卷 413-420页

作者： C. z. Tan Laboratory of Solid State Microstructure and Department of Materials Science and Engineering Nanjing University 210093 Nanjing China Institut für Mineralogie Freie Universitt Berlin 14195 Berlin Germany

The surface structure and properties are different from those of the bulk, depending on the substrate materials and deposition condition, and playing an important role in precise optical components. The conventional spectroscopic methods to monitor the surface structure are restricted only in several layers of molecules. It is known that the penetration depth of the incident light increases with its wavelength and decreases with the angle of incidence. Thus infrared spectroscopy provides a powerful means for determination of surface structure and the depth profile up to micrometers. By recording the reflection spectra at different angles of incidence, the surface structure and its depth profile can be monitored successively. Further, the incident field has the subcomponents parallel and perpendicular to the surface, which excite the transverse and longitudinal optic modes, respectively. Change of the polariz.tion direction of the incident light provides a practical function to study anisotropic property of the surface and the interaction between the transverse and longitudinal optic modes. In this work, infrared spectrophotometer was applied to investigate the depth profile in microstructure of silica glass. Combining with the glass fiber system, this technique can be used for in-situ control of the deposition process. In comparing with ellipsometry, this method reveals both structural and constitutional information.

关键词：硅石光谱红外线表面结构光学材料

Alfvén waves in temperature anisotropic Cairns distributed plasma

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Communications in Theoretical Physics 2020年第3期72卷 83-87页

作者： S Ayaz.imran A Khan z.Iqbal G Murtaz. Salam Chair Department of PhysicsGC University Lahore Katchery Road54000 LahorePakistan

The dispersion relations and Landau damping of Alfven waves in kinetic and inertial limits are studied in temperature anisotropic Cairns distributed *** the case of kinetic Alfven waves(KAWs),it is found that the real frequency is enhanced when either the electron perpendicular temperature or the non-thermal parameter A *** inertial Alfven waves(IAWs),the real frequency is slightly affected by the electron temperature anisotropy and *** the real frequency,the damping rate of KAWs is reduced when the electron perpendicular temperature or A *** the case of IAWs,the temperature anisotropy and A either enhance or reduce the damping rate depending upon the perpendicular *** results may be helpful to understand the dynamics of KAWs and IAWs in space plasmas where the non-Maxwellian distribution of particles are routinely observed.

关键词： Cairns distribution kinetic Alfven waves inertial Alfven waves

The Effect of Non-Contact Conditions in a Splinted Fixed Partial Denture on the Load Sharing Mechanism： A Finite Element Study

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Journal of Bionic Engineering 2012年第3期9卷 336-342页

作者： M. z. Bendjaballah Biomedical Technology Department College of Applied Medical Sciences King Saud University Riyadh Saudi Arabia

A computer-aided design model for a fixed partial denture was constructed and used in a finite element analysis to study the overall load sharing mechanism between the fixed partial denture and oral structures while the denture base rested on the al- veolar ridge. To investigate the consequences of non-contact conditions, three additional models were generated incorporating a uniform clearance of 0.125 mm, 0.25 mm, and 0.5 mm, respectively. A 100 N static load located at the free end of the prosthesis was applied while the distal portion of the jaw was set fixed. The results show that whilst releasing the ridge almost entirely, the presence of the clearance drastically increased the load on the splinting teeth. A pull-out force on the canine tooth of about 44 N was computed, accompanied by a mesio-distal moment of about 500 ***. The combination of which was similar to the tooth extraction maneuver performed by the dentist. In contrast, the second premolar was found to bear a push-in force of almost 115 N. The first molar, though barely solicited in the contact condition, became substantially loaded in non-contact conditions, which validates the choice of sacrificing three teeth to support the denture.

关键词： finite element analysis splinted fixed partial denture hygienic space load transfer mechanism contact problem