检索结果-南通市图书馆

Investigations of Viscous Dissipation in Stagnation Point Flow Past a Stretchable Riga Wall: modern Analysis of Heat Transport

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2019年第4期71卷 377-383页

作者： Aisha Anjum N.A.mir m.Farooq m.javed S.Ahmad Department of mathematics Riphah International University

This article scrutinizes the features of viscous dissipation in the stagnation point ?ow past through a linearly stretched Riga wall by implementing Cattaneo-Christov heat ?ux model. Viscous dissipation is carried out in Cattaneo-Christov diffusion analysis for the ?rst time in this letter. As a result of Cattaneo-Christov model, some extra terms of viscous dissipation are appeared in the energy equation. These extra terms of viscous dissipation are missing in the literature. On the utilization of suitable transformations, the equations governing the problem are reduced under the boundary layer approximation into the non-linear and dimensionless ordinary differential equations. Convergent approach is utilized to solve the dimensionless governing equations. The solution thus acquired is used to highlight the effects of emerging parameters on velocity distribution and ?uid's temperature through the graphs. Features of the drag force(or skin friction co-e?cient) are graphically interpreted. It is noticed that the presence of modi?ed Hartman number helps to reduce the ?uid's temperature but enhances the velocity pro?le. Further an enlargement in the value of thermal time relaxation parameter helps to decrease the temperature distribution.

关键词： stagnation point Cattaneo-Christov theory Riga plate linear stretching viscous dissipation

melting heat transfer with radiative effects and homogeneous–heterogeneous reaction in thermally stratified stagnation flow embedded in porous medium

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2018年第11期25卷 2701-2711页

作者： m.javed m.FAROOQ S.AHmAD Aisha ANJUm Department of mathematics Riphah International UniversityIslamabad 44000Pakistan

The present article deals with thermally stratified stagnation-point flow saturated in porous medium on surface of variable thickness along with more convincing and reliable surface condition termed as melting heat ***–heterogeneous reaction and radiative effects have been further taken into account to reconnoiterproperties of heat *** heat transfer and phenomenon of homogeneous–heterogeneous reaction have engrossed widespread utilization in purification of metals,welding process,electroslag melting,biochemical systems,catalysis and several industrial *** transformations are utilized to attain a scheme of ordinary differential equations possessing exceedingly nonlinear *** process is employed to develop convergent solutions of the resulting *** regarding velocity,thermal field and concentration distribution for several involved parameters is pivotal *** behaviors of skin friction coefficient and Nusselt number are also *** of the reactants is found to depreciate as a result of strength of both heterogeneous and homogeneous reaction *** existence of melting phenomenon,declining attitude of fluid temperature is observed for higher radiation parameter.

关键词： melting heat transfer porous medium stagnation point variable sheet thickness homogeneous– heterogeneous reaction

magneto-hydrodynamic flow of squeezed fluid with binary chemical reaction and activation energy

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2019年第5期26卷 1362-1373页

作者： S.AHmAD m.FAROOQ N.A.mIR Aisha ANJUm m.javed Department of mathematics and Statistics Riphah International University

The present exploration is conducted to describe the motion of viscous fluid embedded in squeezed channel under the applied magnetics *** processes of heat and mass transport incorporate the temperature-dependent binary chemical reaction with modified Arrhenius theory of activation energy function which is not yet disclosed for squeezing flow *** flow,heat and mass regime are exposed to be governed via dimensionless,highly non-linear,ordinary differential equations (ODEs) under no-slip walls boundary conditions.A well-tempered analytical convergent procedure is adopted for the solutions of boundary value problem.A detailed study is accounted through graphs in the form of flow velocity field,temperature and fluid concentration distributions for various emerging parameters of enormous ***-friction,Nusselt and Sherwood numbers have been acquired and disclosed through *** results indicate that fluid temperature follows an increasing trend with dominant dimensionless reaction rate σ and activation energy parameter ***,an increment in σ and E parameters is found to decline in fluid *** current study arises numerous engineering and industrial processes including polymer industry,compression and injection shaping,lubrication system,formation of paper sheets,thin fiber,molding of plastic *** the area of chemical engineering,geothermal engineering,cooling of nuclear reacting,nuclear or chemical system,bimolecular reactions,biochemical process and electrically conducting polymeric flows can be controlled by utilizing magnetic *** by such applications,the proposed study has been developed.

关键词： squeezing flow magneto-hydrodynamics (mHD) activation energy binary chemical reaction

Effect of divalent cations(Co^(2+) and Ni^(2+)) on microstructure,physical properties and application of NdFeO_(3)

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2025年第1期43卷 89-97,I0004页

作者： m.m.Arman materials Science Lab(1) Physics DepartmentFaculty of ScienceCairo UniversityGiza12613Egypt

The nanocrystalline samples Nd_(1-x)m_(x)FeO_(3)(x=0.0 and 0.1;m:Co^(2+)and Ni^(2+))were prepared using the citrate combustion *** X-ray diffraction(XRD)pattern confirmed that the nanoparticles were synthesized in an orthorhombic *** particle size of Nd_(1-x)m_(x)FeO_(3) is in the range of 29-59 *** selected area electron diffraction(SAED)indicates the samples were prepared in a polycrystalline *** samples Nd_(1-x)m_(x)FeO_(3)(x=0.0 and 0.1;m:Co^(2+)and Ni^(2+))have anti ferromagnetic *** Fe^(3+)spins are aligned antiparallel,forming the antiferromagnetic(AFm)properties,which are affected by many factors such as the bond angle between the Fe^(3+)(Fe^(3+)-O_(2)--Fe^(3+))and the Dzyaloshinskii-moriya(D-m)*** doping of Co^(2+)and Ni^(2+)ions in NdFeO_(3) enhances the magnetic properties of the NdFeO_(3).The saturation magnetization(ms)of Nd_(0.90)Co_(0.10)FeO_(3) increases 1.8times more than that of NdFeO_(3).The exchange bias field(HEX)of the Co-doped sample is two times greater than that of NdFeO_(3).The magnetic anisotropy constant(K)of the 10%Co-doped sample increases by 11 factors compared to that of NdFeO_(3).The Tauc plot illustrates that the samples have a direct optical *** divalent cation substitution(Co^(2+)and Ni^(2+))decreases the optical band gap of NdFeO_(3),leading to the recommendation of using the samples Nd_(0.90)Co_(0.10)FeO_(3) and Nd_(0.90)Ni_(0.10)FeO_(3) in photocatalysis of dye degradation from *** removal efficiencies of Cr6+at pH=6 are 88.06%,85.54%,and 85.52%for the samples NdFeO_(3),Nd_(0.90)Co_(0.10)FeO_(3),and Nd_(0.90)Ni_(0.10)FeO_(3),*** Freundlich isotherm mode is the best-fit model for NdFeO_(3) to adsorb Cr6+ions from aqueous solutions.

关键词： Optical properties Nanoparticles magnetic properties Perovskites Removal efficiency Rareearths

Nonlinear forced vibration in a subcritical regime of a porous functionally graded pipe conveying fluid with a retaining clip

在线全文

学校读者我要写书评

暂无评论

Applied mathematics and mechanics(English Edition) 2025年第1期46卷 101-122页

作者： m.GHOLAmI m.EFTEKHARI Department of mechanical Engineering Shahid Bahonar University of Kerman

This study examines the nonlinear behaviors of a clamped-clamped porous pipe made of a functionally graded material(FGm) that conveys fluids and is equipped with a retaining clip, focusing on primary resonance and subcritical dynamics. The nonlinear governing equations for the FGm pipe are derived by the extended Hamilton's principle, and subsequently discretized through the application of the Galerkin *** direct method of multi-scales is then used to solve the derived equations. A thorough analysis of various parameters, including the clip stiffness, the power-law index, the porosity, and the clip location, is conducted to gain a comprehensive understanding of the system's nonlinear dynamics. Through the analysis of the first natural frequency, the study highlights the influence of the flow velocity and the clip stiffness, while the comparisons with metallic pipes emphasize the role of FGm composition. The examination of the forced response curves reveals saddle-node bifurcations and their dependence on parameters such as the detuning parameter and the power-law index, offering valuable insights into the system's nonlinear resonant behavior. Furthermore, the frequency-response curves illustrate the hardening nonlinearities influenced by factors such as the porosity and the clip stiffness, revealing nuanced effects on the system response and resonance characteristics. This comprehensive analysis enhances the understanding of nonlinear behaviors in FGm porous pipes with a retaining clip, providing key insights for practical engineering applications in system design and optimization.

关键词： functionally graded material (FGm) pipe conveying fluid O175.2 porosity primary resonance retaining clip subcritical regime

Soliton formation in electron-temperature-gradient-driven magnetoplasma

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Plasma Science and Technology 2018年第2期20卷 82-86页

作者： m Yaqub KHAN javed IQBAL Department of mathematics Riphah International University

Electron-temperature-gradient（ETG）-driven solitons are studied in a *** derive the linear dispersion relation and an admitted solitary wave solution Korteweg–de Vries-typeequation（Kd V）for the ETG mode in the nonlinear regime by using the Braginskii model and a *** is found that the ETG mode supports only rarefactive *** is also observed that the ratio of electron-to-ion temperature t=T T,e ithe ratio of gradient scale lengths h=L L,（en） Tand the magnetic field B affect both the amplitude and width of a *** is found that the soliton profile changes with variation in these *** apply the homotopy perturbation method to the derived Kd V *** is found this method is computationally attractive and the results are very *** work may be useful to study the low electrostatic modes in inhomogeneous electron–ion plasma with density and *** illustration,the model has been applied to tokamak plasma.

关键词： ETG mode KdV equation HPm

Effect of Lanthanum on Nodule Count and Nodularity of Ductile Iron

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2007年第5期25卷 533-536页

作者： m. Ashraf Sheikh javed Iqbal University of Engineering & Technology

The present study aims at finding out the effect of the addition of a single rare earth element, that is, lanthanum on the nodularity and nodule count of ductile iron under controlled conditions. For this purpose, four melts with different compositions were made, using a 28 kg inductotherm medium frequency induction furnace. The temperature was carefully maintained between 1400 and 1450 ℃ for these heats. A good quality charge consisting of Sorel metal, ferrosilicon, Swedish iron, ferrosilicon magnesium, and ferrosilicon lanthanum was used for the production of melts. A vertically parted sand mould was used for casting of 10 test bars made from local silica sand. Standard coin samples were chill-cast to conduct chemical analysis of the ductile iron. mierostructure study of the samples was conducted using a Leica optical microscope. Nodule count and nodularity of the samples were carried out using an image analyzer. The results obtained indicated that with the increased addition of lanthanum the nodule count of ductile iron increased, thus making it evident that it played a significant role in increasing the mechanical properties. The highest nodule count of 467 was obtained with the addition of 0.03% lanthanum. However, the effect of lanthanum on nodularity was negligible with nodularity ranging from 81% to 83 %.

关键词： ductile iron mischmetal nodulization nodulafity nodule count rare earths

Honeycomb-spiderweb-inspired self-similar hybrid cellular structures for impact applications

在线全文

学校读者我要写书评

暂无评论

Defence Technology(防务技术) 2025年第1期43卷 182-200页

作者： K.Tewari m.K.Pandit m.m.mahapatra P.R.Budarapu School of mechanical Sciences Indian Institute of Technology BhubaneswarBhubaneswar752050India

Inspired by nature's self-similar designs,novel honeycomb-spiderweb based self-similar hybrid cellular structures are proposed here for efficient energy absorption in impact *** energy absorption is enhanced by optimizing the geometry and topology for a given *** proposed hybrid cellular structure is arrived after a thorough analysis of topologically enhanced self-similar *** optimized cell designs are rigorously tested considering dynamic loads involving crush and high-velocity bullet ***,the influence of thickness,radial connectivity,and order of patterning at the unit cell level are also *** maximum crushing efficiency attained is found to be more than 95%,which is significantly higher than most existing traditional *** on,the first and second-order hierarchical self-similar unit cell designs developed during crush analysis are used to prepare the cores for sandwich *** tests are performed on the developed sandwich structures using the standard 9-mm *** influence of multistaging on impact resistance is also investigated by maintaining a constant total thickness and mass of the sandwich ***,in order to avoid layer-wise weak zones and hence,attain a uniform out-of-plane impact strength,off-setting the designs in each stage is *** sandwich structures with first and second-order self-similar hybrid cores are observed to withstand impact velocities as high as 170 m/s and 270 m/s,respectively.

关键词： Sandwich structures Honeycomb-spider web inspired Self-similar hierarchy Crush analysis High-velocity impact Strong and weak zones multistaging

Discovering causal models for structural,construction and defense-related engineering phenomena

在线全文

学校读者我要写书评

暂无评论

Defence Technology(防务技术) 2025年第1期43卷 60-79页

作者： m.Z.Naser School of Civil&Environmental Engineering and Earth Sciences(SCEEES) Clemson UniversityClemsonSouth Carolina 29634USA The Artificial Intelligence Research Institute for Science and Engineering(AIRISE) Clemson UniversityClemsonSouth Carolina 29634USA

Causality,the science of cause and effect,has made it possible to create a new family of *** models are often referred to as causal *** those of mathematical,numerical,empirical,or machine learning(mL)nature,causal models hope to tie the cause(s)to the effect(s)pertaining to a phenomenon(i.e.,data generating process)through causal *** paper presents one of the first works at creating causal models in the area of structural and construction *** this end,this paper starts with a brief review of the principles of causality and then adopts four causal discovery algorithms,namely,PC(Peter-Clark),FCI(fast causal inference),GES(greedy equivalence search),and GRa SP(greedy relaxation of the sparsest permutation),have been used to examine four phenomena,including predicting the load-bearing capacity of axially loaded members,fire resistance of structural members,shear strength of beams,and resistance of walls against impulsive(blast)*** from this study reveal the possibility and merit of discovering complete and partial causal ***,this study also proposes two simple metrics that can help assess the performance of causal discovery algorithms.

关键词： Causality Causal discovery Directed acyclic graphs machine learning metrics