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Chinese Physics C 2022年第12期46卷 271-287页

作者： saibal ray Arijit Panda Bivash Majumder Md.Rabiul Islam Goutam Manna Centre for Cosmology Astrophysics and Space Science(CCASS)GLA UniversityMathura 281406Uttar PradeshIndia Department of Physics Prabhat Kumar CollegeContaiPurba Medinipur 721404India&Department of PhysicsRaiganj UniversityRaiganjUttar Dinajpur 733134West BengalIndia Department of Mathematics Prabhat Kumar CollegeContaiPurba Medinipur-721404India Department of Physics Raiganj UniversityRaiganjUttar Dinajpur 733134West BengalIndia Department of Physics Prabhat Kumar CollegeContaiPurba Medinipur-721404India

In this study,we investigate the collapsing scenario for the k-essence emergent Vaidya spacetime in the context of massive gravity's *** this study,we consider that the background metric is Vaidya spacetime in massive gravity's *** show that the k-essence emergent gravity metric closely resembles the new type of generalized Vaidya massive gravity metric with the rainbow deformations for null fluid collapse,where we consider the k-essence scalar field as a function solely of the advanced or the retarded *** k-essence emergent Vaidya massive gravity rainbow mass function is also *** new type k-essence emergent Vaidya massive gravity rainbow metric satisfies the required energy *** existence of a locally naked central singularity and the strength and strongness of the singularities for the rainbow deformations of the k-essence emergent Vaidya massive gravity metric are the interesting outcomes of the present work.

关键词： classical general relativity physics of black holes classical black holes k-essence

Studies on modified power law inflation

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Chinese Physics C 2023年第3期47卷 273-281页

作者： Prasenjit Paul Rikpratik Sengupta saibal ray Department of Physics Government College of Engineering and Ceramic TechnologyKolkataWest Bengal 700010India Department of Physics Aliah UniversityAction Area IlNewtownKolkataWest Bengal 700156India Centre of Cosmology Astrophysics and Space Science(CCASS)GLA UniversityMathuraUttar Pradesh 281406India

In this study,we evaluate power law inflation(PLI)with a monomial potential and obtain a novel exact *** is well known that the conventional PLI with an exponential potential is inconsistent with the Planck *** the standard PLI,the present model does not encounter the graceful exit problem,and the results agree fairly well with recent *** our analysis,we calculate the spectral index and the tensor-to-scalar ratio,both of which agree very well with recent observational data and are comparable with those of other modified inflationary *** employed technique reveals that the large cosmological constant decreases with the expansion of the universe in the case of the *** coupling of the inflaton with gravitation is the primary factor in this *** basic assumption here is that the two metric tensors in the gravitational and inflaton parts correspond to different conformal frames,which contradicts with the conventional PLI,where the inflaton is directly coupled with the background metric *** fact has direct applications to different dark energy models and the assisted quintessence theory.

关键词： power law inflation conformal coupling inflaton cosmological constant

f(■,L(X))-gravity in the context of dark energy with power law expansion and energy conditions

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Chinese Physics C 2023年第2期 194-211页

作者： Goutam Manna Arijit Panda Aninda Karmakar saibal ray Md.Rabiul Islam Department of Physics Prabhat Kumar College Department of Physics Raiganj University Centre for Cosmology Astrophysics and Space Science (CCASS) GLA University

The objective of this work is to generate a general formalism of f(R,L(X))-gravity in the context of dark energy under the framework of K-essence emergent geometry with the Dirac-Born-Infeld(DBI) variety of action,where R is the familiar Ricci scalar,L(X) is the DBI type non-canonical Lagrangian with X=1/2gμν▽μφ▽νφ,and φ is the K-essence scalar *** emergent gravity metric(Gμν) and the well known gravitational metric(gμν)are not conformally *** have constructed a modified field equation using the metric formalism in f(R,L(X))-gravity incorporating the corresponding Friedmann equations into the framework of the background gravitational metric,which is of Friedmann-Lemaitre-Robertson-Walker(FLRW) *** solution of the modified Friedmann equations have been deduced for the specific choice of f(R,L(X)),which is of Starobinsky-type,using the power law expansion *** consistency of the model with the accelerating phase of the universe has been shown when we restrict ourselves to consider the value of the dark energy density as φ2=8/9=0.888 <1,which indicates that the present universe is dark-energy *** plots for the energy density(ρ),pressure(p),and equation of state parameter(ω) with respect to(w.r.t.) time(t) based on parametric values are interestingly consistent with the dark energy domination theory,and hence the accelerating *** also highlight the corresponding energy conditions and constraints of the f(R,L(X)) theory with a basic example.

关键词： modified theories of gravity dark energy K-essence model Friedman equations energy conditions

Anisotropic stars in modified gravity:An extended gravitational decoupling approach

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Chinese Physics C 2022年第10期46卷 239-258页

作者： S.K.Maurya B.Mishra saibal ray Riju Nag Department of Mathematical and Physical Sciences College of Arts and ScienceUniversity of NizwaNizwaSultanate of Oman Department of Mathematics Birla Institute of Technology and Science-PilaniHyderabad CampusHyderabad 500078India Centre for Cosmology Astrophysics and Space Science(CCASS)GLA UniversityMathura 281406Uttar PradeshIndia Department of Mathematics and Physical Sciences College of Arts and SciencesUniversity of NizwaNizwaSultanate of Oman

In this study,we conduct an investigation on decoupling gravitational sources under the framework of f(R,T)***,the complete geometric deformation technique is employed,which facilitates finding the exact solutions to the anisotropic astrophysical system smoothly without imposing any particular ansatz for the deformation *** addition,we used 5-dimensional Euclidean spacetime in order to describe the embedding Class Ⅰ spacetime in order to obtain a solvable spherical physical *** resulting solutions are both physically interesting and viable with new possibilities for ***,the present investigation demonstrates that the mixture of f(R,T)+CGD translates to a scenario beyond the pure GR realm and helps to enhance the features of the interior astrophysical aspects of compact stellar *** determine the physical acceptability and stability of the stellar system based on the obtained solutions,we conducted a series of physical tests that satisfied all stability criteria,including the nonsingular nature of density and pressure.

关键词： modified gravity embedding class I spacetime neutron stars

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

Effect of metal fractions on rice grain metal uptake and biological parameters in mica mines waste contaminated soils

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Journal of Environmental Sciences 2024年第2期136卷 313-324页

作者： saibal Ghosh Sandip Mondal Jajati Mandal Abhishek Mukherjee Pradip Bhattacharyya Agricultural and Ecological Research Unit Indian Statistical InstituteGiridihJharkhand 815301India School of Science Engineering&EnvironmentUniversity of SalfordManchester M54WTUK

Heavy metals from mica waste not only deteriorate the soil quality but also results in the uptake of metals in the *** present investigation was conducted to evaluate the effects of different fractions of metals on the uptake in rice,soil microbial and biochemical properties in mica waste-contaminated soils of Jharkhand,*** each active mine,soil samples were randomly collected at distances of100 m(zone 3).Sequential metal extraction was used to determine the fractions of different metals(nickel(Ni),cadmium(Cd),chromium(Cr)and lead(Pb))including water-soluble(Ws)and exchangeable metals(Ex),carbonate-bound metals(CBD),Fe/Mn oxide(OXD)bound metals,organically bound metals(ORG),and residues(RS).The Ni,Cr,Cd and Pb in rice grain were 0.83±0.41,0.41±0.19,0.21±0.14 and 0.17±0.08 mg/kg *** the variable importance plot of the random forest(RF)algorithm,the Ws fraction of Ni,Cr and Cd and Ex fraction of Pb was the most important predictor for rice grain metal ***,the partial dependence plots(PDP)give us an insight into the role of the two most important metal fractions on rice grain metal *** microbial and enzyme activity was significantly and negatively correlated with Ws and Ex metal fractions,indicating that water-soluble and exchangeable fractions exert a strong inhibitory effect on the soil microbiological parameters and enzyme activities.

关键词： Metal fractions Microbial parameters Mica waste soil Soil enzymes Rice Random forest

f(R,L(X))-gravity in the context of dark energy with power law expansion and energy conditions

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Chinese Physics C 2023年第2期47卷 190-207页

作者： Goutam Manna Arijit Panda Aninda Karmakar saibal ray Md.Rabiul Islam Department of Physics Prabhat Kumar CollegeContaiPurba Medinipur 721404India Department of Physics Prabhat Kumar CollegeContaiPurba Medinipur 721404India&Department of PhysicsRaiganj UniversityRaiganjUttar Dinajpur 733134West BengalIndia Department of Physics Prabhat Kumar ColegeContaiPurba Medinipur 721404India Centre for Cosmology Astrophysics and Space Science(CCASS)GLA UniversityMathura 281406Uttar PradeshIndia Department of Physics Raiganj UniversityRaiganjUttar Dinajpur 733134West BengalIndia

The objective of this work is to generate a general formalism of f(R,L(X))-gravity in the context of dark energy under the framework of K-essence emergent geometry with the Dirac-Born-Infeld(DBI) variety of action,where R is the familiar Ricci scalar,L(X) is the DBI type non-canonical Lagrangian with X=1/2g^(μν)▽_(μ)φ▽_(ν)φ,and φ is the K-essence scalar *** emergent gravity metric(G_(μν)) and the well known gravitational metric(g^(μν))are not conformally *** have constructed a modified field equation using the metric formalism in f(R,L(X))-gravity incorporating the corresponding Friedmann equations into the framework of the background gravitational metric,which is of Friedmann-Lemaitre-Robertson-Walker(FLRW) *** solution of the modified Friedmann equations have been deduced for the specific choice of f(R,L(X)),which is of Starobinsky-type,using the power law expansion *** consistency of the model with the accelerating phase of the universe has been shown when we restrict ourselves to consider the value of the dark energy density as φ^(2)=8/9=0.888 <1,which indicates that the present universe is dark-energy *** plots for the energy density(ρ),pressure(p),and equation of state parameter(ω) with respect to(w.r.t.) time(t) based on parametric values are interestingly consistent with the dark energy domination theory,and hence the accelerating *** also highlight the corresponding energy conditions and constraints of the f(R,L(X)) theory with a basic example.

关键词： modified theories of gravity dark energy K-essence model Friedman equations energy conditions

Appraisal of pollution and health risks associated with coal mine contaminated soil using multimodal statistical and Fuzzy-TOPSIS approaches

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Frontiers of Environmental Science & Engineering 2024年第5期18卷 101-115页

作者： Sumit Kumar Sonali Banerjee saibal Ghosh Santanu Majumder Jajati Mandal Pankaj Kumar Roy Pradip Bhattacharyya Agricultural and Ecological Research Unit Indian Statistical InstituteGiridih815301India Department of Life and Environmental Sciences Bournemouth University(Talbot Campus)Fern BarrowPooleBH12 5BBUK School of Sciences Engineering & EnvironmentUniversity of SalfordSalfordM5 4QJUK School of Water Resource Engineering Jadavpur UniversityKolkata700032India School of Environmental Studies Jadavpur UniversityKolkata700032India

The present study assesses the concentration,probabilistic risk,source classification,and dietary risk arising from heavy metal(HMs)pollution in agricultural soils affected by coal mining in eastern part of *** of soil and rice plant indicated significantly elevated levels of HMs beyond the permissible limit in the contaminated zones(zone 1:PbSoil:108.24±72.97,CuSoil:57.26±23.91,CdSoil:8.44±2.76,CrSoil:180.05±46.90,NiSoil:70.79±25.06 mg/kg;PbGrain:0.96±0.8,CuGrain:8.6±5.1,CdGrain:0.65±0.42,CrGrain:4.78±1.89,NiGrain:11.74±4.38 mg/*** 2:PbSoil:139.56±69.46,CuSoil:69.89±19.86,CdSoil:8.95±2.57,CrSoil:245.46±70.66,NiSoil:95.46±22.89 mg/kg;PbGrain:1.27±0.84,CuGrain:7.9±4.57,CdGrain:0.76±0.43,CrGrain:8.6±1.58,NiGrain:11.50±2.46 mg/kg)compared to the uncontaminated zone(zone 3).Carcinogenic and non-carcinogenic health risks were computed based on the HMs concentration in the soil and rice grain,with Pb,Cr,and Ni identified as posing a high risk to human *** Carlo simulation,the solubility-free ion activity model(FIAM),and severity adjusted margin of exposure(SAMOE)were employed to predict health *** hazard quotient(HQ)values for Ni,Cr,Cd,and Pb were>1,indicating a significant non-carcinogenic ***(risk thermometer)results for contaminated zones ranged from low to moderate risk(CrSAMOE:0.05,and NiSAMOE:0.03).Fuzzy-TOPSIS and variable importance plots(from random forest)showed that Ni and Cr were mostly responsible for the toxicity in the rice plant,respectively.A self-organizing map for source classification revealed common origin for the studied HMs with zone 2 exhibiting the highest *** positive matrix factorization model for the source apportionment identified coal mining and transportation as the predominant sources of *** distribution analysis indicated higher contamination near mining sites as compared to distant sampling ***,this study will aid environmental scientists and policymakers controllin

关键词： Coal mine Free ion activity model Monto Carlo Simulation Pollution and Health risk Fuzzy-TOPSIS

Novel Lyapunov-based rapid and ripple-free MPPT using a robust model reference adaptive controller for solar PV system

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Protection and Control of Modern Power Systems 2023年第1期8卷 205-229页

作者： saibal Manna Ashok Kumar Akella Deepak Kumar Singh Department of Electrical Engineering National Institute of Technology JamshedpurJharkhand 831014India

The technological,economic,and environmental benefits of photovoltaic(PV)systems have led to their wide-spread adoption in recent years as a source of electricity ***,precisely identifying a PV system’s maximum power point(MPP)under normal and shaded weather conditions is crucial to conserving the maximum generated *** of the biggest concerns with a PV system is the existence of partial shading,which produces multiple peaks in the P–V characteristic *** these circumstances,classical maximum power point tracking(MPPT)approaches are prone to getting stuck on local peaks and failing to follow the global maximum power point(GMPP).To overcome such obstacles,a new Lyapunov-based Robust Model Reference Adaptive Controller(LRMRAC)is designed and implemented to reach GMPP rapidly and *** proposed controller also achieves MPP accurately under slow,abrupt and rapid changes in radiation,temperature and load *** and OPAL-RT real-time simulators in various scenarios are performed to verify the superiority of the proposed approach over the other state-of-the-art methods,i.e.,ANFIS,INC,VSPO,and P&*** and GMPP are accomplished in less than 3.8 ms and 10 ms,*** on the results presented,the LRMRAC controller appears to be a promising technique for MPPT in a PV system.

关键词： Photovoltaic(PV) MPPT Partial shading Lyapunov-based robust model reference adaptive control(LRMRAC) Lyapunov stability

New proposal of modulation of amplitude-squeezed state of light by intensity variation of a low-frequency coherent message signal

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Chinese Optics Letters 2015年第1期13卷 93-96页

作者： saibal Mitra Sourangshu Mukhopadhyay Department of Physics The University of BurdwanBurdwan 713104West BengalIndia

Squeezed state of light explores a new era in noiseless communication and data processing recently breaking the quantum limit of noise. We propose a new mechanism of modulating an amplitude-squeezed signal with the instantaneous intensity variation of a coherent signal. The modulating signal is a coherent light where the amplitude-squeezed light takes the role of a carrier signal.

关键词： New proposal of modulation of amplitude-squeezed state of light by intensity variation of a low-frequency coherent message signal