检索结果-南通市图书馆

Food and Nutrition Sciences 2013年第8期4卷 83-92页

作者： Biswapathik.Pahari Sandipan Chak.aborty Bidisha Sengupta Sudip Chaudhuri William Martin Jasmine Taylor Jordan Henley Donald Davis pradip k. biswas Amit k. Sharma Pradeep k. Sengupta Biophysics Division Saha Institute of Nuclear Physics Kolkata India Department of Chemistry Tougaloo College Tougaloo USA Department of Physics Tougaloo College Tougaloo USA. Saroj Mohan Institute of Technology Hooghly West Bengal India Department of Physics Tougaloo College Tougaloo USA.

Steady state and time resolved fluorescence spectroscopy, combined with molecular dynamics simulation, have been used to explore the interactions of a therapeutically important bioflavonoid, genistein, with normal human hemoglobin (HbA). Binding constants estimated from the fluorescence studies were k.= (3.5 ± 0.32) ×104M-1 for genistein. Specific interactions with HbA were confirmed from flavonoid-induced fluorescence quenching of the tryptophan in the protein HbA. The mechanism of this quenching involves both static and dynamic components as indicated by: (a) increase in the values of Stern-Volmer quenching constants with temperatures, (b) / is slightly > 1 (where and are the unquenched and quenched tryptophan fluorescence lifetimes (averaged) respectively). Molecular dock.ng and dynamic simulations reveal that genistein binds between the subunits of HbA, ~18?? away from the closest heme group of chain α1, emphasizing the fact that the drug does not interfere with oxygen binding site of HbA.

关键词： Natural Drug Carrier Fluorescence Circular Dichroism Molecular Dynamics Dock.ng

Effect of pouring temperature on cooling slope casting of semi-solid Al-Si-Mg alloy

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2012年第5期25卷 329-339页

作者： Prosenjit Das Sudip k. Samanta Himadri Chattopadhyay pradip Dutta Foundry Group CSIR-Central Mechanical Engineering Research Institute Durgapur-713209 India Department of Mechanical Engineering Jadavpur University Kolkata-70032 India Department of Mechanical Engineering Indian Institute of Science Bangalore-560012 India

Present trend of semi-solid processing is directed towards rheocasting route which allows manufacturing of near-net-shape cast components directly from the prepared semi-solid slurry. Generation of globular equi-axed grains during solidification of rheocast components, compared to the columnar dendritic structure of conventional casting routes, facilitates the manufacturing of components with improved mechanical properties and structural integrity. In the present investigation, a cooling slope has been designed and indigenously fabricated to produce semi solid slurry of A1-Si-Mg （A356） alloy and successively cast in a metallic mould. The scope of the present work.discusses about development of a numerical model to simulate the liquid metal flow through cooling slope using Eulerian two-phase flow approach and to investigate the effect of pouring temperature on cooling slope semi-solid slurry generation process. The two phases considered in the present model are liquid metal and air. Solid fraction evolution of the solidifying melt is track.d at different locations of the cooling slope, following Schiel＇s equation. The continuity equation, momentum equation and energy equation are solved considering thin wall boundary condition approach. During solidification of the liquid metal, a modified temperature recovery scheme has been employed tak.ng care of the latent heat release and change of fraction of liquid. The results obtained from simulations are compared with experimental findings and good agreement has been found.

关键词： Rheocasting Semi-solid slurry Cooling slope A356 alloy Numerical simulation

Euler-Euler CFD modeling of fluidized bed:Influence of specularity coefficient on hydrodynamic behavior

在线全文

学校读者我要写书评

暂无评论

Particuology 2013年第6期11卷 673-680页

作者： Chanchal Loha Himadri Chattopadhyay pradip k.Chatterjee Thermal Engineering Group CSIR-Central Mechanical Engineering Research Institute Department of Mechanical Engineering Jadavpur University

Euler-Euler two-fluid model is used to simulate the hydrodynamics of gas-solid flow in a bubbling flu- idized bed with Geldert B particles where the solid property is calculated by applying the k.netic theory of granular flow （k.GF）. Johnson and Jack.on wall boundary condition is used for the particle phase, and different amount of slip between particle and wall is given by varying the specularity coefficient （φ） from 0 to 1. The simulated particle velocity, granular temperature and particle volume fraction are compared to investigate the effect of different wall boundary conditions on the hydrodynamic behavior, Some of the results are also compared with the available experimental data from the literature. It was found that the model predictions are sensitive to the specularity coefficient. The hydrodynamic behavior deviated sig- nificantly for φ = 0 and φ = 0.01 with maximum deviation found at φ = 0 i.e. free-slip condition. However, the overall bed height predicted by all the conditions is similar.

关键词： Fluidized bed Hydrodynamics Specularity coefficient CFD

Geochemical characteristics of Holocene sediments from Chuadanga district, Bangladesh: Implications for weathering, climate, redox conditions, provenance and tectonic setting

在线全文

学校读者我要写书评

暂无评论

Chinese Journal Of Geochemistry 2014年第4期33卷 336-350页

作者： Ismail Hossain k.isna k.nta Roy pradip k.mar biswas Mahbubul Alam Md. Moniruzzaman Farah Deeba Department of Geology and Mining University of Rajshahi Bangladesh Institute of Mining Mineralogy and Metallurgy (IMMM) Joypurhat Bangladesh Water Resource Planning Division Institute of Water Modelling (IWM) Dhaka Bangladesh Institute of Nuclear Science and Technology (INST) Atomic Energy Commission Dhaka Bangladesh

The present research deals with the geochemical characteristics of the Holocene sediments from Alamdanga area, Chuadanga district, Bangladesh. Main goals of the study are to delineate source rock.characteristics, degree of chemical weathering and sorting processes and behavior of redox conditions during deposition of the sediments. Geochemical characteristics of the sediments show comparatively a wide variation in accordance with stratigraphy in their major element contents(e.g. Si O2 69.46–82.13, Al2O3 2.28–8.88 in wt%), reflecting the distinctive provenance and in part an unstable period in terms of tectonic activity. Geochemical classification of the sediments shows mostly sub-ark.se with few sub-litharenites. Some major and trace elements display comprehensible correlation with Al2O3 confirming their possible hydraulic fractionation. The chemical index of alteration(CIA*), W* index, index of compositional variability(ICV), plagioclase index of alteration(PIA*) values and the ratio of Si O2/Al2O3, suggest low degrees of chemical weathering in the source areas as well as immature to moderately mature the sediments. The sediments suggest semi-arid climatic trends within oxic deltaic depositional conditions during the Holocene, at 3–12 k.. Whole rock.geochemistry and discrimination diagrams demonstrate the continental signature derivatives, which might have been derived from the felsic to intermediate igneous rock.(granitic plutonic rock.) as well as from quartzose sedimentary/metamorphic provenance. These typical sources are present in a vast region of the Himalayan belt and catchment areas of Ganges. The tectonic setting of the sediments demarcates typically passive margin with slightly continental arc system.

关键词：地球化学特征氧化还原条件化学风化沉积物构造背景孟加拉国气候趋势全新世

Effect of coefficient of restitution in Euler-Euler CFD simulation of fluidized-bed hydrodynamics

在线全文

学校读者我要写书评

暂无评论

Particuology 2014年第4期12卷 170-177页

作者： Chanchal Loha Himadri Chattopadhyay pradip k.Chatterjee Thermal Engineering Division CSIR-Central Mechanical Engineering Research InstituteDurgapur 713209India Department of Mechanical Engineering Jadavpur UniversityKolkata 700032India

Collision between particles plays an important role in determining the hydrodynamic characteristics of gas-solid flow in a fluidized bed. In the present work. earlier work.（Loha, Chattopadhyay, ＆ Chatterjee, 2013） was extended to study the effect of the elasticity of particle collision on the hydrodynamic behavior of a bubbling fluidized bed filled with 530-~m particles. The Eulerian-Eulerian two-fluid model was used to simulate the hydrodynamics of the bubbling fluidized bed, where the solid-phase properties were calculated by applying the k.netic theory of granular flow. To investigate the effect of the elasticity of particle collision, different values of the coefficient of restitution were applied in the simulation and their effects were studied in detail. Simulations were performed for two different solid-phase wall boundary conditions. No bubble formation was observed for perfectly elastic collision. The bubble formation started as soon as the coefficient of restitution was set below 1.0, and the space occupied by bubbles in the bed increased with a decrease in the coefficient of restitution. Simulation results were also compared with experimental data available in the literature, and good agreement was found for coefficients of restitution of 0.95 and 0.99.

关键词： Coefficient of restitution Fluidization Hydrodynamics Computational fluid dynamics Euler-Euler approach

Analytical Approach for Nonlinear Partial Differential Equations of Fractional Order

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2013年第9期60卷 269-277页

作者： pradip Roul Visvesvaraya National Institute of Technology Department of Mathematics

The purpose of the paper is to present analytical and numerical solutions of a degenerate parabolic equation with time-fractional derivatives arising in the spatial diffusion of biological populations. The homotopy-perturbation method is employed for solving this class of equations, and the time-fractional derivatives are described in the sense of Caputo. Comparisons are made with those derived by Adomian＇s decomposition method, revealing that the homotopy perturbation method is more accurate and convenient than the Adomian＇s decomposition method. Furthermore, the results reveal that the approximate solution continuously depends on the time-fractional derivative and the proposed method incorporating the Caputo derivatives is a powerful and efficient technique for solving the fractional differential equations without requiring linearization or restrictive assumptions. The basis ideas presented in the paper can be further applied to solve other similar fractional partial differential equations.

关键词： reaction-diffusion equation fractional calculus Homotopy-perturbation method biological pop-ulation model Mittag-Leffler function

Geochemistry of subsurface Late Quaternary ironstones in Rajshahi and Bogra Districts, Bangladesh: implications for genetic and depositional conditions

在线全文

学校读者我要写书评

暂无评论

Acta Geochimica 2019年第3期38卷 404-413页

作者： Md.Sazzadur Rahman Ismail Hossain pradip k.mar biswas Md.Abdur Rahim A.S.M.Mehedi Hasan Md.Ibrahim Adham Department of Geology and Mining University of Rajshahi Institutes of Mining Mineralogy and Metallurgy (IMMM)BCSIR Department of Disaster Resilience and Engineering Patuakhali Science and Technology University

The present study deals with the geochemistry of Late Quaternary ironstones in the subsurface in Rajshahi and Bogra districts, Bangladesh with the lithological study of the boreholes sediments. Major lithofacies of the studied boreholes are clay, silty clay, sandy clay, fine to coarse grained sand, gravels and sands with(fragmentary) ironstones. The ironstones contain major oxides, Fe_2 O_3*(*total Fe)(avg. 66.6 wt%), SiO_2(avg. 15.3 wt%), Al_2 O_3(avg. 4.0 wt%), MnO(avg. 7.7 wt%), and CaO(avg. 3.4 wt%). These geochemical data imply that the higher percentage of Fe_2 O_3* along with Al_2 O_3 and MnO indicate the ironstone as goethite and siderite, which is also validated by XRD data. A comparatively higher percentage of SiO_2 indicates the presence of relative amounts of clastic quartz and manganese-rich silicate or clay in these rock.. These ironstones also have significant amounts of MnO(avg. 7.7 wt%) suggesting their depositional environments under oxygenated condition. Chemical data of these ironstones suggest that the source rock.suffered deep chemical weathering and iron was mostly carried in association with the clay fraction and organic matter. Iron concretion was mostly formed by bacterial build up in swamps and marshes, and was subsequently embedded in clayey *** the coastal environments, the water table fluctuates and goethite and siderite with mud and quartz became dry and compacted to form ironstone.

关键词： Ironstone Geochemistry Goethite Siderite Bangladesh

Lak.hanhatti stromatolite, India： Biogenic or abiogenic？

在线全文

学校读者我要写书评

暂无评论

Journal of Palaeogeography 2016年第3期5卷 292-310页

作者： Adrita Choudhuri Subir Sark.r Wladyslaw Altermann Soumik.Muk.opadhyay pradip k.Bose Department of Geological Sciences Jadavpur University Kolkata 700032 India Department of Geology University of Pretoria Pretoria 0002 South Africa

Abstract The extraordinary lateral continuity of isopachous stromatotite laminae in the -87 m-thick.Mesoproterozoic Lak.hanhatti Dolomite （India） evinces chemical precipitation. Fan-shaped crystals grown on tamina surfaces further corroborate this contention; growth of fan-shaped crystats under the overhanging stromatolite column-margin indicates direct carbonate precipitation from ambient waters. The fan-shaped crystats are stack.d up, separated onty by thin dark.micritic taminae. In a retativety upper stratigraphic in- terval of the formation, tighter laminae characterized by a dotted texture and traversed by numerous winding tubutar voids change graduatty upwards into dark.micritic taminae. Some sporadicatty distributed lenticutar intraciastic beds also have the similarly dark.micritic coatings. Ctear carbonate cement crusts atso occur between laminae and between successive dark.micritic coats around intraciasts. DuU cathodotuminescence （CL） characterizes this cement as weU as the cement lining within earty dia^enetic voids, in contrast, the taminae with dotted textures show dirty orange luminescence, white the dark.micritic taminae and the dark.micritic grain-coats display dear bright orange luminescence. Pyrite and its pseudomorphs are preferabty concentrated along the dark.micritic laminae. Carbon content in these dark.micritic components, whether laminae or coats, is much higher than in the lighter components, exceeding what can be accounted for their CaMg（COs）2 composition. A large part of this carbon is k.rogen, ptausibly biogenic. The dark.components are, therefore, reasonably, though not unequivocally, assumed to be microbial mats. Degradation of the mats might have given rise to the tight laminae with dotted textures. The fuzzy-margin tubes within the tight laminae probabty manifest the escape of gases generated during organic matter decomposition. Si-At-rich terrigenous fines thinty draping the dark.carbonaceous taminae was possibty the resutt of baft

关键词： StromatoHte Lamina continuity Mesoproterozoic Lak.hanhatti Dolomite Member Inorganicprecipitation k.rogen enrichment Filamentous microbiota

Performance evaluation for selectivity of the flocculant on hematite in selective flocculation

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2013年第12期20卷 1123-1129页

作者： Lopamudra Panda pradip k.Banerjee Surendra k.mar Biswal R.Venugopal N.R.Mandre Research and Development Tata Steel Ltd. Institute of Minerals and Materials Technology (Council of Scientific and Industrial Research) Indian School of Mines University

Increased demand for iron ore necessitates the utilization of low-grade iron ore fines, slimes, and existing tailings. Selective flocculation can be an alternative physico-chemical process for utilizing these low-grade fines, slimes, and tailings. In selective fiocculation, the most critical objective is the selection of proper reagents that will mak. fioc of desired minerals. In present study, selective flocculation was applied to ultra-fine synthetic mixtures of hematite and k.olinite, and the Fe value was upgraded up to 65.78% with the reduction of Al2O3 and SiO2 values to 2.65% and 3.6670, respectively. Here, degraded wheat starch was used as a *** this process, separation occurs on the basis of the selectivity of the flocculant. The selectivity of the fiocculant can be quantified in terms of separation efficiency. Here, an attempt was also made to develop a correlation between separation efficiency and major operating parameters such as flocculent dose, pH value, and solid concentration to predict the separation performance.

关键词： hematite k.olinite selective fiocculation modeling iron ores tailings

Streptozotocin induced Alzheimer's disease lik. changes and the underlying neural degeneration and regeneration mechanism

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2015年第7期10卷 1050-1052页

作者： pradip k.mar k.mat Department of Anasthesiology Center for Translational Research in Neurodegenerative Disease College of MedicineUniversity of Florida

Alzheimer’s disease（AD）is a neurodegenerative disorder which is remark.bly characterized by pathological hallmark. that include neurofibrillary tangles,neuronal loss extracellular senile plaques containing aggregated amyloid beta（Aβ）,and neurofibrillary tangles composed of the hyperphosphorylated form of the microtubule protein *** is the most common form of dementia which is characterized by severe neurodegenerative changes such as loss of neurons and synapses in brain（k.mat et al.,2014）.

关键词： STZ Streptozotocin induced Alzheimer’s disease lik. changes and the underlying neural degeneration and regeneration mechanism AD