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Exact Solution of a(2+1)-Dimensional Anisotropic Star in Finch and Skea Spacetime

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Communications in Theoretical Physics 2014年第8期61卷 221-226页

作者： Piyali Bhar farook rahaman Ritabrata Biswas Hafiza Ismat Fatima Department of Mathematics Jadavpur University Department of Mathematics besus howrah india Department of Mathematics Govt. Degree College (W) Warburton nankana sahib pakistan

We provide a new class of interior solution of a(2+1)-dimensional anisotropic star in Finch and Skea spacetime corresponding to the BTZ black hole. We develop the model by considering the MIT bag model EOS and a particular ansatz for the metric function grrproposed by Finch and Skea [M.R. Finch and J.E.F. Skea, Class. Quantum.Grav. 6(1989) 467]. Our model is free from central singularity and satisfies all the physical requirements for the acceptability of the model.

关键词： (2+1)-dimensional anisotropic star Finch and Skea spacetime

Exploring physical properties of compact stars in f(R,T)-gravity:An embedding approach

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Chinese Physics C 2020年第10期44卷 190-204页

作者： Ksh.Newton Singh Abdelghani Errehymy farook rahaman Mohammed Daoud Department of Physics National Defence AcademyKhadakwaslaPune-411023India Department of Mathematics Jadavpur UniversityKolkata-700032India Laboratory of High Energy Physics and Condensed Matter(LPHEMaC) Department of PhysicsFaculty of Sciences Aïn ChockUniversity of Hassan IIB.P.5366 MaarifCasablanca 20100Morocco Department of Physics Faculty of SciencesUniversity of Ibn TofailB.P.133Kenitra 14000Morocco Abdus Salam International Centre for Theoretical Physics MiramareTrieste 34151Italy

Solving field equations exactly in f(R,T)−gravity is a challenging task.To do so,many authors have adopted different methods such as assuming both the metric functions and an equation of state(EoS)and a metric function.However,such methods may not always lead to well-behaved solutions,and the solutions may even be rejected after complete calculations.Nevertheless,very recent studies on embedding class-one methods suggest that the chances of arriving at a well-behaved solution are very high,which is inspiring.In the class-one approach,one of the metric potentials is estimated and the other can be obtained using the Karmarkar condition.In this study,a new class-one solution is proposed that is well-behaved from all physical points of view.The nature of the solution is analyzed by tuning the f(R,T)−coupling parameterχ,and it is found that the solution leads to a stiffer EoS forχ=−1 than that forχ=1.This is because for small values ofχ,the velocity of sound is higher,leading to higher values of Mmax in the M−R curve and the EoS parameterω.The solution satisfies the causality condition and energy conditions and remains stable and static under radial perturbations(static stability criterion)and in equilibrium(modified TOV equation).The resulting M−R diagram is well-fitted with observed values from a few compact stars such as PSR J1614-2230,Vela X-1,Cen X-3,and SAX J1808.4-3658.Therefore,for different values ofχ,the corresponding radii and their respective moments of inertia have been predicted from the M−I curve.

关键词： f(R,T)-gravity Karmarkar's condition exact solutions compact star

Particles and Scalar Waves in Noncommutative Charged Black Hole Spacetime

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Communications in Theoretical Physics 2015年第7期64卷 1-8页

作者： Piyali Bhar farook rahaman Ritabrata Biswas U.F.Mondal Department of Mathematics Jadavpur University Department of Mathematics Krishnagar Women’s College Department of Mathematics Behala College

In this paper we have discussed geodesics and the motion of test particle in the gravitational field of noncommutative charged black hole spacetime. The motion of massive and massless particle have been discussed seperately.A comparative study of noncommutative charged black hole and usual Reissner–Nordstr¨om black hole has been done.The study of effective potential has also been included. Finally, we have examined the scattering of scalar waves in noncommutative charged black hole spacetime.

关键词： test particle scalar waves noncommutative charged

Relativistic models of anisotropic superdense star in the regime of Karmarkar's condition

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Communications in Theoretical Physics 2023年第2期75卷 168-179页

作者： Bikram Keshari Parida Shreya Majumder Shyam Das Koushik Chakraborty farook rahaman Department of Physics Pondicherry UniversityKalapetPuducherry 605014India Department of Physics North Bengal St.Xavier’s CollegeJalpaiguriWest Bengal735135India Department of Physics Malda CollegeMalda 732101West BengalIndia Department of Physics Government College of EducationBurdwanWest Bengal712103India Department of Mathematics Jadavpur UniversityKolkata 700032West BengalIndia

We obtained a new class of solutions for a relativistic anisotropic compact star by utilizing the Karmarkar embedding condition.To obtain the closed-form solution a suitable form of one of the gravitational potentials has been chosen to determine the other by analyzing the Karmarkar condition.The resulting solutions are found to be well-behaved and regular and could describe a compact stellar object.Considering the current estimated values of the mass and radius of the pulsar 4U1820-30 as input parameters,all the physically relevant parameters are shown to be well-behaved to a very good degree of accuracy.

关键词： anisotropic compact star embedding class one Karmarkar’s condition

C-field cosmological models:revisited

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Research in Astronomy and Astrophysics 2016年第12期16卷 75-88页

作者： Anil Kumar Yadav Ahmad Tawfiq Ali Saibal Ray farook rahaman Iflikar Hossain Sardar Department of Physics United College of Engineering and ResearchGreater Noida 201306India Department of Mathematics King Abdul Aziz UniversityPO Box 80203Jeddah 21589Saudi Arabia&Department of MathematicsFaculty of ScienceA1-Azhar UniversityNasr City11884CairoEgypt Department of Physics Government College of Engineering and Ceramic TechnologyKolkata 700010West BengalIndia Department of Mathematics Jadavpur UniversityKolkata 700032West BengalIndia

We investigate plane symmetric spacetime filled with perfect fluid in the C-field cosmology of Hoyle and Narlikar. A new class of exact solutions has been obtained by considering the creation field C as a function of time only. To get the deterministic solution, it has been assumed that the rate of creation of matter-energy density is proportional to the strength of the existing C-field energy density. Several physical aspects and geometrical properties of the models are discussed in detail, especially showing that some of our solutions of C-field cosmology are free from singularity in contrast to the Big Bang cosmology. A comparative study has been carried out between two models, one singular and the other nonsingular, by contrasting the behaviour of the physical parameters. We note that the model in a unique way represents both the features of the accelerating as well as decelerating universe depending on the parameters and thus seems to provide glimpses of the oscillating or cyclic model of the universe without invoking any other agent or theory in allowing cyclicity.

关键词： cosmology： miscellaneous -- cosmology： theory -- cosmology： early universe

Haemoglobin Measurement from Eye Anterior Ciliary Arteries through Borescope Camera

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Computer Systems Science & Engineering 2023年第2期44卷 1763-1774页

作者： Mohamed Abbas Ahamed farook S.Rukmanidevi N.R.Shanker Department of Electronics and Communication Engineering Vel Tech Multi Tech Dr Rangarajan Dr Sakunthala Engineering CollegeChennai600062India Department of Electronics and Communication Engineering R.M.D Engineering CollegeChennai601206India Department of Computer Science and Engineering Aalim Muhammed Salegh College of EngineeringChennai600055India

Nowadays,smartphones are used as self-health monitoring devices for humans.Self-health monitoring devices help clinicians with big data for accurate diagnosis and guidance for treatment through repetitive measurement.Repetitive measurement of haemoglobin requires for pregnant women,pediatric,pulmonary hypertension and obstetric patients.Noninvasive haemoglobin measurement through conjunctiva leads to inaccurate measurement.The inaccuracy is due to a decrease in the density of goblet cells and acinar units in Meibomian glands in the human eye as age increases.Furthermore,conjunctivitis is a disease in the eye due to inﬂammation or infection at the conjunctiva.Conjunctivitis is in the form of lines in the eyelid and covers the white part of the eyeball.Moreover,small blood vessels in eye regions of conjunctiva inﬂammations are not visible to the human eye or standard camera.This paper proposes smartphone-based hae-moglobin(SBH)measurement through a borescope camera from anterior ciliary arteries of the eye for the above problem.The proposed SBH method acquires images from the anterior ciliary arteries region of the eye through a smartphone attached with a high megapixel borescope camera.The anterior ciliary arteries are projected through transverse dyadic wavelet transform(TDyWT)and applied with delta segmentation to obtain blood cells from the ciliary arteries of the eye.Furthermore,the Gaussian regression algorithm measures haemoglobin(Hb)with more accuracy based on the person,eye arteries,red pixel statistical parameters obtained from the left and right eye,age,and weight.Furthermore,the experimen-tal result of the proposed SBH method has an accuracy of 96%in haemoglobin measurement.

关键词： Hemoglobin measurement borescope camera smartphone anterior ciliary arteries region

Synthesis and Characterization of New 3-（3-Hydroxyphenyl）-4- alkyl-3,4-dihydrobenzo[e][1,3]oxazepine-1,5-dione Compounds

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Chinese Journal of Chemistry 2011年第7期29卷 1518-1522页

作者： Osman, Hasnah Mohammad, AbdulKarim-Talaq Yeap, Guan-Yeow Adam, farook School of Chemical Sciences Universiti Sains Malaysia Minden 11800 Penang Malaysia

A series of 3-（3-hydroxyphenyl）-4-alkyl-3,4-dihydrobenzo[e][1,3]oxazepine-l,5-dione compounds with general formula CnH2n＋1CNO（CO）2C6H4（C6HnOH） in which n are even parity numbers from 2 to 18. The structure deter- minations on these compounds were performed by FT-IR spectroscopy which indicated that the terminal alkyl chain attached to the oxazepine ring was fully extended. Conforrnational analysis in DMSO at ambient temperature was carried out for the first time via high resolution 1H NMR and 13C NMR spectroscopy.

关键词： 3,4-dihydrobenzo[e]oxazepine-l,5-diones synthetic method structure elucidication

用于Friedel-Craft甲苯苯甲酰化反应的铟催化剂的多相化(英文)

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催化学报 2012年第11期33卷 1802-1808页

作者： farook ADAM Kei Lin SEK School of Chemical Sciences Universiti Sains MalaysiaPenang 11800Malaysia

Indium incorporated silica samples with different indium contents were synthesized using a template free sol-gel method.The silica used was extracted from rice husk(RH) and the resulting catalyst was labeled as RH-xIn(x = 5%,10%,15%,and 20%).From the N2 adsorption analysis the presence of type IV isotherm in RH-blank and RH-xIn indicated the mesoporous nature of the catalysts.In the XRD pattern,a broad band at ca.2θ = 25° was observed for all the catalysts which showed them to be amorphous.TEM micrographs revealed that the material is composed of nanoparticles.Friedel-Craft benzoylation of toluene was carried out using the RH-xIn catalyst.The optimum conditions for the benzoylation of toluene were determined and at 373 K,100% conversion and 89% selectivity for the para-product(i.e.4-methylbenzophenone) were obtained.

关键词： LFCO XRD 化学化学动力学

稻壳SiO_2/钒催化剂上苯乙酮液相氧化(英文)

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催化学报 2012年第3期33卷 518-522页

作者： farook ADAM Thiam-Seng CHEW Jeyashelly ANDAS School of Chemical Sciences Universiti Sains Malaysia

Rice husk silica catalyst loaded with 10 wt% vanadium was synthesized from agricultural biomass via a sol-gel synthetic route at pH = 9. The catalyst was characterized by different physico-chemical methods. The FTIR spectra showed the formation of Si–O–V and V=O stretching bands. The presence of vanadium was confirmed by EDX elemental analysis. RH-10V possessed a high specific surface area of 276 m2/g and pore volume of 0.83 ml/g. The prepared catalyst possessed a narrow pore size distribution centered around 7.9 nm. The catalytic performance of RH-10V was tested in the oxidation of acetophenone at 70 ℃. RH-10V was found to be an active catalyst in the oxidation of acetophenone, producing 36.28% conversion efficiency. The products identified were benzoic acid, 2-hydroxyacetophenone, phenol, acetic acid, and 3-hydroxyacetophenone.

关键词： catalyst 液相氧化钒催化剂 benzoic 苯乙酮 presence sol-gel surface