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Pedosphere 2019年第5期29卷 554-568页

作者： Tanmoy PAUL Nimai Chandra saha National Institute of Cholera and Enteric Diseases Kolkata 700010 (India) Fishery and Ecotoxicology Research Laboratory (Vice-Chancellor}s Research Group) Department of ZoologyThe University of BurdwanBurdwan 713104 (India)

Bioaccumulation of selenium and arsenic resulting from geogenic activities and aggravated by anthropogenic actions has now become a serious environmental issue. Different parts of the world are experiencing issues of selenium and arsenic contamination, especially in soil and ground water. The present selenium and arsenic contamination scenario has been well represented in contemporary literature, and there are an array of remediation techniques targeting the decontamination of environmental contamination. The use of microbe-mediated remediation of selenium and arsenic contamination is gaining scientific attention for sustainable environmental bioremediation. The present review elucidates the different aspects of selenium and arsenic contamination, bioaccumulation, and bioremediation with implications for successful decontamination of these heavy metals.

关键词： bioaccumulation biogeochemistry chemical species contaminant decontamination heavy metal microbial remediation microorganism

Quenched Fe moment in the collapsed tetragonal phase of Ca_(1-x)Pr_x Fe_2As_2

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Chinese Physics B 2013年第5期22卷 55-59页

作者：马龙吉高峰代佳 saha s R Drye T Paglione J 于伟强 Department of Physics Renmin University of China Center for Nanophysics and Advanced Materials Department of PhysicsUniversity of MarylandCollege Park

We report 7sAs NMR studies on single crystals of rare-earth doped iron pnictide superconductor Ca1-xPrxFe2As2. In both cases of x = 0.075, 0.15, a large increase of Vq upon cooling is consistent with the tetragonal-collapsed tetragonal structure transition. A sharp drop of the Knight shift is also seen just below the structure transition, which suggests the quenching of Fe local magnetism, and therefore offers important understanding of the collapsed tetragonal phase. At even low temperatures, the 1/75 T1 is enhanced and forms a peak at T ≈ 25 K, which may be caused by the magnetic ordering of the Pr3＋ moments or soin dynamics of mobile domain walls.

关键词： quenched Fe moment collapsed tetragonal phase iron pnictides nuclear magnetic resonance

Applying deep learning and benchmark machine learning algorithms for landslide susceptibility modelling in Rorachu river basin of sikkim Himalaya, India

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Geoscience Frontiers 2021年第5期12卷 264-280页

作者： Kanu Mandal sunil saha sujit Mandal Department of Geography University of Gour BangaMalda 732103West BengalIndia Department of Geography Diamond Harbour Woman’s UniversityDiamond HarbourWest BengalIndia

Landslide is considered as one of the most severe threats to human life and property in the hilly areas of the *** number of landslides and the level of damage across the globe has been increasing over ***,landslide management is essential to maintain the natural and socio-economic dynamics of the hilly *** river basin is one of the most landslide-prone areas of the sikkim selected for the present *** prime goal of the study is to prepare landslide susceptibility maps(LsMs)using computer-based advanced machine learning techniques and compare the performance of the *** properly understand the existing spatial relation with the landslide,twenty factors,including triggering and causative factors,were selected.A deep learning algorithm *** neural network model(CNN)and three popular machine learning techniques,i.e.,random forest model(RF),artificial neural network model(ANN),and bagging model,were employed to prepare the *** separate datasets including training and validation were designed by randomly taken landslide and nonlandslide points.A ratio of 70:30 was considered for the selection of both training and validation *** was assessed by tolerance and variance inflation factor,and the role of individual conditioning factors was estimated using information gain *** result reveals that there is no severe multicollinearity among the landslide conditioning factors,and the triggering factor rainfall appeared as the leading cause of the *** on the final prediction values of each model,LsM was constructed and successfully portioned into five distinct classes,like very low,low,moderate,high,and very high *** susceptibility class-wise distribution of landslides shows that more than 90%of the landslide area falls under higher landslide susceptibility *** precision of models was examined using the area under the curve(AUC)of the receiver operating characteristi

关键词： Machine learning techniques Information gain ratio(IGR) Landslide susceptibility map(LsM) Convolutional neural network(CNN) Receiver operating characteristics(ROC)

Doubly Excited 1,3Fe states of Two-Electron Atoms under Weakly Coupled Plasma Environment

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Communications in Theoretical Physics 2019年第7期71卷 853-860页

作者： s. Dutta J. K. saha s. Bhattacharyya T. K. Mukherjee Belgharia Texmaco Estate school BelghariaKolkata 700056India Department of Physics Naxula Institute of TechnologyAgarparaKolkata 700109India Department of Physics Aliah UniversityIIA/27NewtownKolkata 700160India Department of Physics Acharya Prafulla Chandra CollegeNew BarrackporeKolkata 700131India

Precise energy eigenvalues of metastable bound doubly excited 1,3Fe states originating from 2 pnf(n=4–6)configuration of helium-like ions(Z=2–4)under weakly coupled plasma(WCP)environment have been estimated within the framework of Ritz variational *** wavefunction is expanded in explicitly correlated Hylleraas type basis *** screened Coulomb potential is consideredas mimic the WCP *** atomic systems tend towards gradual instability and the number of excited metastable bound states reduces with increasing plasma *** wavelengths corresponding to 2 pnf(1,3F^e)→2 pnf(1,3Do)(n=4–6;n′=3–6)transitions occurring between doubly excited states of plasma embedded two-electron ions are also reported.

关键词： two-electron atom doubly excited states variational method weakly coupled plasma Hylleraas co-ordinate

Implications of REE incorporation and host sediment influence on the origin and growth processes of ferromanganese nodules from Central Indian Ocean Basin

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Geoscience Frontiers 2021年第3期12卷 609-623页

作者： simontini sensarma Abhishek saha Arghya Hazra CsIR-National Institute of Oceanography Dona PaulaGoa 403004India Indian Institute of science BangaloreKarnataka 560012India school of Earth Ocean and Atmospheric SciencesGoa UniversityGoa 403206India

This study presents new major,trace and REE data for thirty-five ferromanganese nodules recovered from areas representing three different sediment types(siliceous,red clay and their transition zone)in the Central Indian Ocean Basin(CIOB)to address their genetic aspects,classification,growth rate,nature of host sediments and influence of REE in the processes of nodule *** nodules from CIOB are mostly either hydrogenetic(metals coming from oxygenated bottom water)and diagenetic(metals coming from suboxic sediment pore water)or a combination of both,depending on the source of supply of ***,a number of biogeochemical processes mediate this supply of metals which again changes from time to time,making the nodule growth process highly *** study suggests that at the initial stage of nodule growth,host sediments do not play much role in controlling the growth processes for which REEs can enter both Mn and Fe oxyhydroxide phases ***,the bottom water signature is imprinted in these early formed nodules irrespective of their host sediment substrate but with gradual growth and burial in the sediment,the main mode of metal enrichment becomes diagenetic through sediment pore *** tends to increase the concentration of Mn,Ni and Cu over other elements which are retained in the sediment *** the REEs,Ce concentration of the nodules shows significant positive anomaly due to variation in redox potential and hence its magnitude can be used to get an idea about the metal enrichment procedure and the genetic type of the ***,based on host sediment only,not much difference is found in the magnitude of Ce anomaly in these *** the other hand,discrimination diagram,based on HFsE and REY chemistry,indicates that most of these nodules are of diagenetic origin under oxic condition with a trend towards hydrogenetic ***,the genetic type of the ferromanganese nodules from the CIOB are more effectively differentiated

关键词： Central Indian Ocean Basin Ferromanganese nodules Deep-sea sediments Rare earth elements Geochemical discrimination

Fourier Collocation and Reduced Basis Methods for Fast Modeling of Compressible Flows

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Communications in Computational Physics 2022年第8期32卷 595-637页

作者： Jian Yu Deep ray Jan s.Hesthaven school of Aeronautic science and Engineering Beihang UniversityBeijing 100191China Laboratory of Aero-thermal Protection Technology for Aerospace Vehicles China Aerospace Science and Technology CorporationBeijing 100048China school of Aerospace and Mechanical Engineering University of Southern CaliforniaLos AngelesCA 90089USA Chair of ComputationalMathematics and simulation schience Ecole Polytechnique Federale de LausanneLausanne CH-1015Switzerland

A projection-based reduced order model(ROM)based on the Fourier collocation method is proposed for compressible *** incorporation of localized artificial viscosity model and filtering is pursued to enhance the robustness and accuracy of the ROM for shock-dominated ***,for Euler systems,ROMs built on the conservative and the skew-symmetric forms of the governing equation are *** ensure efficiency,the discrete empirical interpolation method(DEIM)is *** alternative reduction approach,exploring the sparsity of viscosity is also investigated for the viscous terms.A number of one-and two-dimensional benchmark cases are considered to test the performance of the proposed *** show that stable computations for shock-dominated cases can be achieved with ROMs built on both the conservative and the skew-symmetric forms without additional stabilization components other than the viscosity model and *** the same parameters,the skew-symmetric form shows better robustness and accuracy than its conservative counterpart,while the conservative form is superior in terms of efficiency.

关键词： Projection-based reduced order modeling Fourier collocation artificial viscosity compressible flow

Tuff beds in Kurnool subbasin,southern India and implications for felsic volcanism in Proterozoic intracratonic basins

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Geoscience Frontiers 2012年第4期3卷 429-444页

作者： Dilip saha Vikash Tripathy Geological studies Unit lndian Statistical InstituteKolkata 700108India A-1/79 Sector-18RohiniNew Delhi 110089India

A first report on tuff beds from the Owk shale in the Proterozoic Kurnool sub-basin in southern India is presented. The rhyolitic to rhodacitic tufts, overlying shelfal limestones formed at depths below storm wave base, have rheomorphie features indicative of viscoplastic flow, and geochem- ical signatures of rhyolitic to rhyodacitic unwelded to welded tufts, similar to those described from other Proterozoic intracratonic basins like Vindhyan and Chhattisgarh basins in India. Fragmentary nature of altered glass with perlitic cracks and local admixture with intrabasinal sediments suggest phreatomag- matic reactions. The widespread and repeated occurrences of felsic tufts in these basins, possibly derived from low degree melting of continental crust, suggest intermittent tectonothermal instability which likely influenced basinal topography and cyclic development of the carbonate platforms.

关键词： Felsic tuff Intracratonic basin Kumool subbasin Owk shale Proterozoic

A Novel Variant of Moth Flame Optimizer for Higher Dimensional Optimization Problems

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Journal of Bionic Engineering 2023年第5期20卷 2389-2415页

作者： saroj Kumar sahoo sushmita sharma Apu Kumar saha Department of Mathematics National Institute of Technology AgartalaJiraniaTripura799046India

Moth Flame Optimization(MFO)is a nature-inspired optimization algorithm,based on the principle of navigation technique of moth toward *** to less parameter and easy implementation,MFO is used in various field to solve optimization ***,for the complex higher dimensional problems,MFO is unable to make a good trade-off between global and local *** overcome these drawbacks of MFO,in this work,an enhanced MFO,namely WF-MFO,is introduced to solve higher dimensional optimization *** a more optimal balance between global and local search,the original MFO’s exploration ability is improved by an exploration operator,namely,Weibull flight *** addition,the local optimal solutions have been avoided and the convergence speed has been increased using a Fibonacci search process-based technique that improves the quality of the solutions ***-nine benchmark functions of varying complexity with 1000 and 2000 dimensions have been utilized to verify the projected *** popular algorithms and MFO versions have been compared to the achieved *** addition,the robustness of the proposed WF-MFO method has been evaluated using the Friedman rank test,the Wilcoxon rank test,and convergence *** to other methods,the proposed WF-MFO algorithm provides higher quality solutions and converges more quickly,as shown by the ***,the proposed WF-MFO has been used to the solution of two engineering design issues,with striking *** improved performance of the proposed WF-MFO algorithm for addressing larger dimensional optimization problems is guaranteed by analyses of numerical data,statistical tests,and convergence performance.

关键词： Moth Flame Optimization(MFO)algorithm Bio-inspired algorithm Fibonacci search method Weibull distribution Higher dimensional functions

Conduction-radiation effect on natural convection flow in fluid-saturated non-Darcy porous medium enclosed by non-isothermal walls

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Applied Mathematics and Mechanics(English Edition) 2013年第6期34卷 687-702页

作者： M. A. HOssAIN M. sALEEM s. C. saha A. NAKAYAMA Department of Mathematics COMSATS Institute of Information Technology school of Chemistry Physics & Mechanical Engineering Queensland University of Technology Department of Mechanical Engineering Shizuoka University

The combined effect of conduction-convection-radiation on natural convec- tion flow of an optically thick Newtonian fluid with gray radiant properties, confined in a porous media square cavity with Darcy-Brinkman-Forchheimer drag is studied numeri- cally. For a gray fluid, Rosseland diffusion approximation is considered. It is assumed that （i） the temperature of the left vertical wall varies linearly with height, （ii） the right vertical and top walls are at a lower temperature, and （iii） the bottom wall is uniformly-heated. The governing equations are solved using the alternate direct implicit method together with the successive over relaxation technique. The investigation of the effect of governing parameters, namely, the Forschheimer resistance （F）, the temperature difference （A）, and the Plank number （Rd）, on the flow pattern and heat transfer characteristics is carried out. It can be seen that the reduction of flow and heat transfer occur as the Forschheimer resistance is increased. On the other hand, both the flow strength and heat transfer in- crease as the temperature ratio A is increased.

关键词： conduction-convection-radiation,Darcy-Brinkman-Forchheimer drag porousmedium enclosure

Rotational asymmetry of reactant concentration and its evolution in a circulating fluidized bed riser

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Particuology 2012年第5期10卷 573-581页

作者： Ajay K.ray Madhumita B.ray Jesse Zhu Department of Chemical and Biochemical Engineering The University of Western OntarioLondonOntario N6A 5B9 Canada

Rotational asymmetric distribution of reactant （ozone） concentration and its evolution along with the gas-solid reactive flow were studied in a 76 mm i.d., 10.2 m high circulating fluidized bed （CFB） riser reactor. The superficial gas velocity ranged from 3 to 5 m/s and the solids circulation rates were 50 and 100 kg/（m2 s）. Experimental results show that the asymmetry of reactant distribution can extend to a height close to the length of flow developing zone of the CFB riser reactor and then disappears. Based on the hydrodynamics of the gas and solid phases in the solids entrance region, this asymmetry can be attributed to the effect of the solids entrance structure.

关键词： Circulating fluidized bedsRiserOzone decompositionRotational asymmetry