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Phantom Accretion onto the Schwarzschild de-Sitter Black Hole

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Chinese Physics Letters 2011年第9期28卷 34-37页

作者： M Sharif G abbas Department of Mathematics University of the PunjabQuaid-e-Azam CampusLahore-54590Pakistan

We deal with phantom energy accretion onto the Schwarzschild de-Sitter black *** energy flux conservation,relativistic Bernoulli equation and mass flux conservation equation are formulated to discuss the phantom *** discuss the conditions for critical *** is found that the mass of the black hole decreases due to phantom *** exist two critical points which lie in the exterior of horizons(black hole and cosmological horizons).The results for the phantom energy accretion onto the Schwarzschild black hole can be recovered by takingΛ→0.

关键词： accretion horizon black

An Efficient Numerical Solution Method for Elliptic Problems in Divergence Form

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Advances in Applied Mathematics and Mechanics 2014年第3期6卷 327-344页

作者： Ali abbas Department of Mathematics Lebanese International UniversityBekaa-RayakLebanon

In this paper the problem−div(a(x,y)∇u)=f with Dirichlet boundary conditions on a square is solved iteratively with high accuracy for u and∇u using a new scheme called“hermitian box-scheme”.The design of the scheme is based on a“hermitian box”,combining the approximation of the gradient by the fourth order hermitian derivative,with a conservative discrete formulation on boxes of length *** iterative technique is based on the repeated solution by a fast direct method of a discrete Poisson equation on a uniform rectangular *** problem is suitably scaled before *** numerical results obtained show the efficiency of the numerical *** work is the extension to strongly elliptic problems of the hermitian box-scheme presented by abbas and Croisille(***.,49(2011),pp.239–267).

关键词： Hermitian scheme box-scheme Kronecker product fast solver iterative method Poisson problem

Fabrication and Growth Mechanism of Single-crystalline Rutile TiO_2 Nanowires by Liquid-phase Deposition Process in a Porous Alumina Template

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Journal of Materials Science & Technology 2015年第8期31卷 828-833页

作者： abbas Sadeghzadeh Attar Zahra Hassani Department of Metallurgy and Materials Engineering University of Kashan Department of Materials Institute of Science and High Technology and Environmental SciencesGraduate University of Advanced Technology

TiO2 nanowire arrays were successfully fabricated by liquid-phase deposition method using porous alumina templates. The obtained TiO2 nanowires were characterized using Raman spectroscopy, X-ray diffraction （XRD）, scanning electron microscopy （SEM）, field emission scanning electron microscopy （FE- SEM）, transmission electron microscopy （TEM）, and selected area electron diffraction （SAED） analysis. Results of electron microscopic observations indicated that the nanowires were smooth and uniform with a diameter of about 50-80 nm and several micrometers in length. SAED, Raman, and XRD mea- surements showed that TiO2 nanowires were single-crystalline with a pure rutile structure after heating at 800 ~C for 10 h. In this situation, the nanowire constituents grew preferentially along the 〈001〉 direction. Furthermore, the formation process and mechanistic study of the Ti02 nanowire arrays were proposed and discussed in detail. The nanowires are clearly produced by the deposition of TiO2 particles on the inner wall of the template nanochannels.

关键词： TiO2 nanowire arrays Single crystal Rutile phase Liquid-phase deposition process

Interaction due to various sources in saturated porous media with incompressible fluid

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Journal of Central South University 2016年第5期23卷 1232-1242页

作者： Rajneesh Kumar Ibrahim A.abbas Department of Mathematics Kurukshetra University Department of Mathematics Faculty of Science and Arts-KhulaisUniversity of Jeddah Nonlinear Analysis and Applied Mathematics Research Group (NAAM) Department of MathematicsKing Abdulaziz University Department of Mathematics Faculty of ScienceSohag University

The disturbance due to mechanical and thermal sources in saturated porous media with incompressible fluid for two-dimensional axi-symmetric problem is *** Laplace and Hankel transforms techniques are used to investigate the *** concentrated source and source over circular region have been taken to show the utility of the *** transformed components of displacement,stress and pore pressure are *** inversion techniques are used to obtain the resulting quantities in the physical domain and the effect of porosity is shown on the resulting *** the field quantities are found to be sensitive towards the porosity *** is observed that porosity parameters have both increasing and decreasing effect on the numerical values of the physical *** the values of the physical quantities are affected by the different boundaries.A special case of interest is also deduced.

关键词： axi-symmetry incompressible porous medium pore pressure Laplace transform Hankel transform concentrated source and source over circular region

Evaluation of plasma sprayed YSZ thermal barrier coatings with the CMAS deposits infiltration using impedance spectroscopy

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Progress in Natural Science:Materials International 2012年第1期22卷 40-47页

作者： Musharaf abbas Key Laboratory of Aerospace Materials & Performance(Ministry of Education) School of Materials Science and EngineeringBeihang Univerisity

The yttria-stabilized zirconia(YSZ) thermal barrier coatings(TBCs) prepared by atmospheric plasma spraying with different heat treatment period at the temperature of 1250 1C were studied in the present *** impedance spectroscopy(EIS) was employed to nondestructively examine the impedance and capacitance behavior of free standing YSZ coatings deposited by plasma spray with CMAS(calcium-magnesium-alumino-silicate) *** circuit was established on the basis of the biomodal structure in *** sintering behavior of the coatings can be reflected by the changes of resistance and capacitance of the *** EIS,the microstructure evolution of the coating with CMAS deposits was discussed in detail.

关键词： Calcium-magnesium-alumino-silicate Thermal barrier coatings Plasma spray Impedance spectroscopy

On systematic development of FSI solvers in the context of particle methods

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Journal of Hydrodynamics 2022年第3期34卷 395-407页

作者： abbas Khayyer Hitoshi Gotoh Yuma Shimizu Department of Civil and Earth Resources Engineering Kyoto UniversityKyotoJapan

This paper presents a review on state-of-the-art of developments corresponding to fluid-structure interaction(FSI)solvers developed within the context of particle *** paper reviews and highlights the potential robustness of entirely Lagrangian meshfree FSI solvers in reproducing FSI corresponding to extreme events and portrays the future perspectives for systematic developments towards reliable engineering applications with respect to rapid advances in technology and emergence of so-called advanced materials that can result in complex and highly non-linear structural ***,the paper highlights the necessity for reproduction of comprehensive structural responses,including viscoelastic,elastoplastic and progressive damages/failures,by the advanced FSI solvers developed within the context of particle *** this regard,extensions of the structure model are suggested to be conducted in a variationally consistent framework to ensure stability,accuracy and physical reliability including thermodynamic *** paper reviews basics of mathematical and numerical modelling for entirely Lagrangian meshfree hydroelastic FSI solvers and presents a brief background on extensions of such solvers towards reproducing viscoelastic structural *** preliminary numerical results on structural viscoelasticity achieved by an extended Hamiltonian SPH(HSPH)model are *** vision paper also concisely portrays the future perspectives for systematic development of particle-based FSI solvers.

关键词： Fluid-structure interaction(FSI) entirely Lagrangian meshfree smoothed particle hydrodynamics(SPH) Hamiltonian SPH(HSPH) viscoelasticity

Beta-cyclodextrin adsorbents to remove water pollutants-a commentary

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Frontiers of Chemical Science and Engineering 2022年第9期16卷 1407-1423页

作者： Fadina Amran Muhammad abbas Ahmad Zaini Centre of Lipids Engineering&Applied Research(CLEAR) Ibnu-Sina Institute for Scientific&Industrial Research(ISI-SIR)Universiti Teknologi MalaysiaJohorMalaysia School of Chemical&Energy Engineering Faculty of EngineeringUniversiti Teknologi MalaysiaJohorMalaysia

Beta-cyclodextrin-based adsorbent is a promising adsorbent because it has unique characteristics and able to form host-guest complexes with various organic *** using beta-cyclodextrin-based adsorbent has continuously improved by various preparation strategies and crosslinking *** commentary aims to highlight the preparation strategies,properties,and adsorption mechanisms of beta-cyclodextrin-based *** adsorbents can be generally classified according to the preparation methods and display high adsorption capacity especially for ***,composite/nanocomposite beta-cyclodextrin-based adsorbents exhibit outstanding adsorption capacity even though the surface area is lower than that of porous and magnetic betacyclodextrin-based *** beta-cyclodextrin/chitosan functionalized graphene oxide hydrogel with specific surface of 17.6 m^(2)·g^(–1)yields an extraordinarily maximum adsorption capacity of 1499 mg·g^(–1)methylene blue,while beta-cyclodextrin/chitosan modified with iron(Ⅱ,Ⅲ)oxide nanoparticles displays a much greater maximum adsorption capacity at 2780 mg·g^(–1).The hydrophobic interaction,functional groups,hydrogen bonding,and electrostatic interaction govern the adsorption to a greater *** this commentary is not exhaustive,the preparation strategies and illustrated mechanisms provide useful insights into the adsorbent–adsorbate interactions,costeffective analysis,challenges,and future directions of betacyclodextrin-based adsorbents in wastewater treatment.

关键词： beta-cyclodextrin adsorbent adsorption inclusion complex mechanism water pollutant wastewater treatment

Numerical simulation of underground seasonal cold energy storage for a 10 MW solar thermal power plant in north-western China using TRNSYS

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Frontiers in Energy 2021年第2期15卷 328-344页

作者： Zulkarnain abbas Yong LI Ruzhu WANG Institute of Refrigeration and Cryogenics Shanghai Jiao Tong UniversityShanghai 200240China College of Environmental Science and Engineering Donghua UniversityShanghai 201620China

This paper aims to explore an efficient, cost-effective, and water-saving seasonal cold energy storage technique based on borehole heat exchangers to cool the condenser water in a 10 MW solar thermal power plant. The proposed seasonal cooling mechanism is designed for the areas under typical weather conditions to utilize the low ambient temperature during the winter season and to store cold energy. The main objective of this paper is to utilize the storage unit in the peak summer months to cool the condenser water and to replace the dry cooling system. Using the simulation platform transient system simulation program (TRNSYS), the borehole thermal energy storage (BTES) system model has been developed and the dynamic capacity of the system in the charging and discharging mode of cold energy for one-year operation is studied. The typical meteorological year (TMY) data of Dunhuang, Gansu province, in north-western China, is utilized to determine the lowest ambient temperature and operation time of the system to store cold energy. The proposed seasonal cooling system is capable of enhancing the efficiency of a solar thermal power plant up to 1.54% and 2.74% in comparison with the water-cooled condenser system and air-cooled condenser system respectively. The techno-economic assessment of the proposed technique also supports its integration with the condenser unit in the solar thermal power plant. This technique has also a great potential to save the water in desert areas.

关键词： seasonal cold energy storage borehole heat exchangers typical meteorological data TRNSYS condenser cooling techno-economic assessment

Design and Fabrication of a Passive Pelvic Orthosis for Treadmill Walking Rehabilitation

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Journal of Bionic Engineering 2023年第3期20卷 1036-1048页

作者： Ali Mokhtarian abbas Fattah Mehdi Keshmiri Department of Mechanical Engineering Khomeinishahr BranchIslamic Azad UniversityKhomeinishahr***Iran Department of Mechanical Engineering Isfahan University of TechnologyIsfahan***Iran

The pelvis plays a significant role in creating smooth and efficient motion during gait. In this study, an orthosis is designed to support pelvis motion of patients with the inability to walk. This assistive device is un-powered and consists of only passive elements. By focusing on the motion of the lower extremities during treadmill walking, a 3D dynamic model of the human body is simulated through a coupled optimization process. Based on two approaches of direct and inverse dynamics, the optimization problems are defined to derive optimum structural parameters of the pelvic orthosis. The optimization results of the direct dynamics problem indicate good matches between the optimized time plots of pelvis rotations with corresponding desired ones. Moreover, by solving the inverse dynamics problem, the minimum value of torque vector of the hip joint of the stance leg during a gait cycle is obtained. Furthermore, by utilizing a prototype of the orthosis, preliminary experiments are conducted on a normal user to validate the model and to investigate the feasibility of using the device for rehabilitation. For this purpose, the rotational movements of the pelvis and energy consumption of the subject in two cases with and without the device are compared during gait on a treadmill. Decreased energy consumption and the compliant motion of the pelvis while using the device verify simulation results and confirm the favorable performance of the assistive device for pelvic support during walking rehabilitation.

关键词： Pelvic support Passive orthosis Dynamic model Optimization Treadmill gait