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Physical aspects of anisotropic compact stars in f(T,T) gravity with off diagonal tetrad

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Chinese Physics C 2021年第8期45卷 190-205页

作者： m.zubair Allah Ditta G.Abbas Rabia Saleem Department of mathematics COMSATS University IslamabadLahore CampusLahorePakistan Department of mathematics The Islamia University of BahawalpurBahawalpurPakistan

This study addresses the formation of anisotropic compact star models in the background of f(T,T)gravity(where T and T represent the torsion and trace of the energy momentum tensor,respectively).f(T,T)gravity is an extension of the f(T)theory,and it allows a general non-minimal coupling between T and *** this setup,we apply Krori and Barua's solution to the static spacetime with the components ξ=Br^(2)+c and ψ=Ar^(2).To develop viable solutions,we select a well-known model f(T,T)=αT^(m)+βT+Ф(where α and β are coupling parameters,and Ф indicates the cosmological constant).We adopt the conventional matching of interior and exterior space time to evaluate the unknowns,which are employed in the stellar *** present a comprehensive discussion on the stellar properties to elaborate the anisotropic nature of compact stars corresponding to well-known models:PSRJ1416-2230,4U1608-52,CenX-3,EXO1785-248,and *** physical analysis,it is observed that the solution of compact spheres satisfy the acceptability criteria,and its models behave optimally and depict stability and consistency,in accordance with f(T,T)gravity.

关键词： f(T,T)gravity compact stars stellar models

REE geochemistry of core sediments of Cauvery delta,India for provenance studies

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Acta Geochimica 2020年第4期39卷 512-526页

作者： malik zubair Ahmad Pramod Singh Department of Geology Satellite Campus LehUniversity of KashmirLehJammu&Kashmir 194104India Department of Earth Sciences School of Physical Chemical and Applied SciencesPondicherry UniversityKalapetPondicherry 605014India

The rare earth element(REE)geochemical composition of sediments from two cores were used to investigate the provenances of the Late Pleistocene to Holocene sediments of Cauvery delta,South *** chondrite-normalized REE patterns and bi-variant plots of Th/Co ***/Sc and La/Th ***/Yb indicated felsic source of ***-normalized plots of REE in both cores are almost parallel and exhibit similar fractionation ratio(Ce/Yb)_N of^***,persistence in REEs patterns implies either uniform source rocks and/or efficient homogenization of sediments during transportation and ***-normalized patterns of the samples show enrichment of light rare earth elements and flat pattern of heavy rare earth elements;such patterns imply dominance of felsic composition rocks in the ***,these samples show quite resemblance with Charnockites and Gneisses of Palani and Kodaikanal hill ***-normalized REE patterns of the Pleistocene sediments of Uttrangudi core show similar abundance,fractionation,and Eu anomaly values as of selected samples from Tertiary rocks near southwest part of the *** attribute the increased input from this region to the upliftment because of tectonic activity and lowering of sea level during the Pleistocene.

关键词： Delta sediments REEs Provenance Rainfall Relief

Application of 0D model of blood flow to study vessel abnormalities in the human systemic circulation: An in-silico study

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International Journal of Biomathematics 2018年第8期11卷 217-234页

作者： R. Gul A. Shahzad m. zubair COmSATS Institute of Information Technology Abbottabad Pakistan

In this paper, a multi-compartment 0D model of the blood flow is considered to study the vessel abnormalities (stenoses and aneurysms) in the human systemic circulation (SC). In the complete SC, different levels of stenosis and aneurysms are artificially created by decreasing and increasing the vessel diameters respectively and their effects on pressure and flow are studied using sensitivity analysis (SA). Normalized local sensitivity analysis (LSA) is used to study the impact of stenosis and aneurysms on pressure and flow wave pattern. Furthermore, global sensitivity analysis (GSA), Sobol's method is used to quantify the overall influence of stenoses and aneurysms in the complete SC. The results of global sensitivity analysis revealed that the impact of both stenoses and aneurysms is strong within the individual structures (arm. legs, carotid bifurcation, aorta), while, aortic stenoses and aneurysms have effect on almost all downstream nodes. moreover, the study could be useful for medical doctors, teachers and students to observe the hemodynamical changes in the SC with respect to vessel abnormalities, which could further help in making any clinical decision for patients having different levels of vessel abnormalities in any part or structure of the SC.

关键词： 0D model systemic circulation sensitivity analysis stenosis aneurysms

Brownian motion and thermophoresis effects on unsteady stagnation point flow of Eyring-Powell nanofluid: a Galerkin approach

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Communications in Theoretical Physics 2020年第12期72卷 71-82页

作者： Z H Khan m Usman T zubair m hamid R U Haq State Key Laboratory of Hydraulics and mountain River Engineering College of Water Resource and HydropowerSichuan UniversityChengdu610065China BIC-ESAT College of EngineeringPeking UniversityBeijing 100871China State Key Laboratory for Turbulence and Complex Systems Department of Mechanics and Engineering SciencePeking UniversityBeijing 100871China Institute of Ocean Research Peking UniversityBeijing 100871China School of mathematical Sciences Peking UniversityBeijing 100871China Department of mechanics and Engineering Science Fudan UniversityShanghai 200433China Department of Electrical Engineering Bahria UniversityIslamabad CampusIslamabad 44000Pakistan

This article concerns the analysis of an unsteady stagnation point flow of Eyring–Powell nanofluid over a stretching *** influence of thermophoresis and Brownian motion is also considered in transport *** nonlinear ODE set is obtained from the governing nonlinear equations via suitable *** numerical experiments are performed using the Galerkin scheme.A tabular form comparison analysis of outcomes attained via the Galerkin approach and numerical scheme(RK-4)is available to show the credibility of the Galerkin *** numerical exploration is carried out for various governing parameters,namely,Brownian motion,steadiness,thermophoresis,stretching ratio,velocity slip,concentration slip,thermal slip,and fluid parameters,and Hartmann,Prandtl and Schmidt *** velocity of fluid enhances with an increase in fluid and magnetic parameters for the case of opposing,but the behavior is reversed for assisting *** Brownian motion and thermophoresis parameters cause an increase in temperature for both cases(assisting and opposing).The Brownian motion parameter provides a drop-in concentration while an increase is noticed for the thermophoresis *** the outcomes and the behavior of emerging parameters are illustrated *** comparison analysis and graphical plots endorse the appropriateness of the Galerkin *** is concluded that said method could be extended to other problems of a complex nature.

关键词： Eyring-Powell fluid stagnation point flow Brownian motion and thermophoresis Galerkin method

Galerkin Finite Element Study on the Effects of Variable Thermal Conductivity and Variable mass Diffusion Conductance on Heat and mass Transfer

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Communications in Theoretical Physics 2018年第7期69卷 49-59页

作者： Imran Haider Qureshi m.Nawaz Shafia Rana T.zubair Department of Applied mathematics and Statistics Institute of Space and TechnologyIslamabad

This article investigates the effects of variable thermal conductivity and variable mass diffusion coefficient on the transport of heat and mass in the flow of Casson fluid. Numerical simulations for two-dimensional flow induced by stretching surface are performed by using Galerkin finite element method(GFEm) with linear shape functions. After assembly process, nonlinear algebraic equations are linearized through Picard method and resulting linear system is solved iteratively using Gauss Seidal method with simulation tolerance 10^(-8). maximum value of independent variableη is searched through numerical experiments. Grid independent study was carried out and error analysis is *** results are validated by comparing with already published results. Parametric study is carried out to explore the physics of the flow. The concentration increases when mass diffusion coefficient is increased. The concentration and thermal boundary layer thicknesses increase when ?_1 and ? are increased. The effect of generative chemical reaction on concentration is opposite to the effect of destructive chemical reaction on the concentration.

关键词： variable diffusion coefficients grid independent study convergence error analysis Nusselt num-ber Casson fluid Joule heating viscous dissipation

Core-shell particles of C-doped CdS and graphene: A noble metal-free approach for efficient photocatalytic H_(2) generation

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Green Energy & Environment 2020年第4期5卷 461-472页

作者： m.ham.ad zubair Estelle marie m.Vanhaecke Ingeborg-Helene Svenum magnus RФnning Jia Yang Department of Chemical Engineering Norwegian University of Science and Technology(NTNU)Sem Sælands vei 4TrondheimNO7491Norway SINTEF Industry P.O.Box 4760 TorgardenTrondheimNO7465Norway

To achieve efficient photocatalytic H_(2) generation from water using earth-abundant and cost-effective materials,a simple synthesis method for carbon-doped CdS particles wrapped with graphene(C-doped CdS@G)is *** doping effect and the application of graphene as cocatalyst for CdS is studied for photocatalytic H_(2) *** most active sample consists of CdS and graphene(CdS-0.15G)exhibits promising photocatalytic activity,producing 3.12 mmol g^-(1) h^-(1) of H_(2) under simulated solar light which is^4.6 times superior than pure CdS nanoparticles giving an apparent quantum efficiency(AQY)of 11.7%.The enhanced photocatalytic activity for H_(2) generation is associated to the narrowing of the bandgap,enhanced light absorption,fast interfacial charge transfer,and higher carrier density(N_(D))in C-doped CdS@G *** is achieved by C doping in CdS nanoparticles and the formation of a graphene shell over the C-doped CdS *** stability test,the spent catalysts sample was also characterized to investigate the nanostructure.

关键词： C-doped CdS@G Core-shell nanostructure Photocatalytic H2 generation Graphene Carbon doping in CdS Bandgap narrowing

Effect of pressure on the electrical properties of flexible NiPc thin films fabricated by rubbing-in technology

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Chinese Physics B 2021年第1期30卷 328-331页

作者： Khasan S Karimov Fahmi F m.ham.adsharif zubair Ahmad m muqeet Rehman Rashid Ali GIK Institute of Engineering Sciences and Technology TopiDistrict SwabiKPK23640Pakistan Center for Innovative Development of Science and New Technologies of Academy of Sciences of Tajikistan Dushanbe734025 Department of Physics Faculty of Science and HealthKoya University44023 KoyaKurdistan Region-F.R.Iraq Center for advanced materials(CAm) Qatar UniversityP.O.Box 2713DohaQatar Department of Electronic Engineering Jeju National UniversityJejuRepublic of Korea

Nickel phthalocyanine(Ni Pc) film was deposited onto the surface of flexible conductive glass by rubbing-in technology and used to fabricate devices based on ITO/Ni Pc/CNT/rubber structure. The I–V characteristics of the devices were investigated under different uniaxial pressures of 200, 280, and 480 gf/cm^(2), applied perpendicular to the surface of the Ni Pc film. Results showed that the nonlinearity coefficients of the I–V curves are in the range of 2 to 3, which was found to be decreased with the increase of the pressure. The rectification ratio of the devices was estimated to be varied from 1.5 to 3 based on the applied pressure. Concluding, the resistance of the active layers was decreased with the increase of both pressure and voltage. We believe that using the rubbing-in technology under sufficient applied pressure it is possible to utilize Ni Pc for the development of various electronic devices such as diodes, nonlinear resistors, and sensors.

关键词： pressure electrical property NiPc thin film rubbing-in technology

multi-objective vendor managed inventory system with interval type-2 fuzzy demand and order quantities

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International Journal of Intelligent Computing and Cybernetics 2021年第3期14卷 439-466页

作者： zubair Ashraf m.ham.ad Shahid South Asian University New DelhiIndiaand Aligarh muslim University AligarhIndia

Purpose-The proposed IT2FmOVmI model intends to concurrently minimize total cost and warehouse space for the single vendor-retailer,multi-item and a consolidated vendor *** demand and order quantities with the deterministic and type-1 fuzzy numbers,we have also formulated the classic/crisp mOVmI model and type-1 fuzzy mOVmI(T1FmOVmI)*** suggested solution technique can solve both crisp mOVmIand *** finding the optimal ordered quantities and backorder levels,the Paretofronts are constructed to form the solution sets for the three ***/methodology/approach-A multi-objective vendor managed inventory(mOVmI)is the most recognized marketing and delivery technique for the service provider and the retail in the supply chain in Industry *** to the evolving market conditions,the characteristics of the individual product,the delivery period and the manufacturing costs,the demand rate and order quantity of the mOVmI device are highly *** such a scenario,a mOVmI system with a deterministic demand rate and order quantity cannot be designed to estimate the highly unforeseen cost of the *** paper introduces a novel interval type-2 fuzzy multi-objective vendor managed inventory(IT2FmOVmI)system,which uses interval type-2 fuzzy numbers(IT2FNs)to represent demand rate and order *** the model is an NP-hard,the well-known meta-heuristic algorithm named NSGA-II(Non-dominated sorted genetic algorithm-II)with EKm(Enhanced Karnink-mendel)algorithm based solution method has been ***-The experimental simulations for the five test problems that demonstrated distinct conditions are considered from the real-datasets of SAPCO *** study concludes that T1FmOVmI and crisp mOVmI schemes are outclassed by IT2FmOVmI model,offering more accurate Pareto-Fronts and efficiency measurement ***/value-Using fuzzy sets theory,a significant amount of work has been already done in past

关键词： multi-objective vendor managed inventory Interval type-2 fuzzy demand Interval type-2 fuzzy ordered quantity Industry 4.0 NSGA-II

Optical sensors based on the NiPc-CoPc composite films deposited by drop casting and under the action of centrifugal force

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Chinese Physics B 2017年第6期26卷 114-118页

作者： Noshin Fatima m.ham.ad m Ahmed Khasan S Karimov zubair Ahmad Fahmi Fariq m.ham.ad Department of Electrical Engineering Capital University of Science and Technology (CUST) Islamabad 44000 Pakistan GIK Institute of Engineering Sciences and Technology Topi District Swabi KPK 23640 Pakistan Center for Innovative Development of Science and New Technologies of Academy of Sciences Aini 299/2 Dushanbe 734063 Tajikistan Center for advanced materials (CAm) Qatar University P. O. Box 2713 Doha Qatar Center for Composites Institute for Vehicle Systems & Engineering Faculty of Mechanical Engineering Universiti Teknologi Malaysia 81310 Johor Bahru Johor Malaysia Soft materials & Devices Laboratory Department of Physics Faculty of Science and Health Koya University Danielle Mitten'and Boulevard Koya 45 Kurdistan Region Iraq

In this study, solution processed composite films of nickel phthalocyanine（NiPc） and cobalt phthalocyanine（CoPc）are deposited by drop casting and under centrifugal force. The films are deposited on surface-type inter-digitated silver electrodes on ceramic alumina substrates. The effects of illumination on the impedance and capacitance of the NiPc–CoPc composite samples are investigated. The samples deposited under centrifugal force show better conductivity than the samples deposited by drop casting technique. In terms of impedance and capacitance sensitivities the samples fabricated under centrifugal force are more sensitive than the drop casting samples. The values of impedance sensitivity（Sz）are equal to（-1.83） mΩ·cm^2/mW and（-5.365） mΩ·cm^2/mW for the samples fabricated using drop casting and under centrifugal force, respectively. Similarly, the values of capacitance sensitivity（Sc） are equal to 0.083 pF·cm^2/mW and 0.185 pF·cm～2/mW for the samples fabricated by drop casting and under centrifugal force. The films deposited using the different procedures could potentially be viable for different operational modes（i.e., conductive or capacitive） of the optical sensors. Both experimental and simulated results are discussed.

关键词： optical sensors capacitive mode impedance mode centrifugal deposition