检索结果-南通市图书馆

Journal of Materials science & Technology 2004年第5期20卷 505-508页

作者： B.Milton Boaz A.Leyo Rajesh s.Xavier Jesu Raja s.jerome das Department of Physics Loyola College Chennai 600 034IndiaDepartment of PhysicsLoyola College Chennai 600 034IndiaDepartment of PhysicsLoyola College Chennai 600 034IndiaDepartment of PhysicsLoyola College Chennai 600 034India

sodium paranitrophenolate dihydrate (NPNa·2H2O) is an excellent semiorganic nonlinear optical (NLO) material, crystallizes both in water and methanol with high degree of transparency. Good optical quality single crystals of dimension upto 18 mm×6 mm×3 mm are obtained by isothermal solvent evaporation technique. The solubility of the crystal in different solvents was measured gravimetrically. The single crystals of NPNa·2H2O show variation in physical properties and growth rate in different solvents. Methanol or ethanol solution yields crystals of bipyramidal shape with clear morphology. However, methanol grown crystal is exhibiting improved hardness parameters and possesses excellent thermal stability as compared to water grown crystals. The effects of solvent on hardness parameter along with thermal and optical properties of NPNa·2H2O was revealed in this paper.

关键词： solution grown crystals semiorganic NLO material solvent effect Absorption spectra Hardness parameters

Growth,structural and Microhardness studies on New semiorganic single Crystals of Calcium Para Nitrophenolate Dihydrate

在线全文

学校读者我要写书评

暂无评论

Journal of Materials science & Technology 2007年第6期23卷 855-859页

作者： C.Vesta R.Uthrakumar C.Justin Raj A.Jonie Varjula J.Mary Linet s.jerome das Department of Physics Loyola CollegeChennai-34India

Good quality crystals of calcium p-nitrophenolate （NPCa） were grown from saturated solution by slow evaporation method. The crystal structure analysis and the molecular arrangement of these crystals were determined using X-ray diffraction （XRD）. From single crystal XRD studies, NPCa is found to be crystallized in the mon- oclinic system with a space group P21/n. The functional groups of the material were confirmed qualitatively by F-FIR （Fourier transform infrared spectroscopy） spectral analysis. Optical absorption studies reveal the absorption region and microhardness studies were carried out to confirm the mechanical behaviour of the crystals.

关键词： Characterization Crystal growth structural analysis FTIR spectral analysis Microhardness UV-Vis analysis

Quantitative mineralogical characterization of chrome ore beneficiation plant tailing and its beneficiated products

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2015年第4期22卷 335-345页

作者： s.K.das CsIR-Institute of Minerals and Materials Technology

Mineralogical characterization and liberation of valuable minerals are primary concerns in rnineml processing industries. The pre- sent investigation focuses on quantitative mineralogy, elemental deportment, and locking-liberation characteristics of the beneficiation of tailings from a chrome ore beneficiation plant in the sukinda region, Odisha; methods used for the study of the beneficiated tailings are QEMsCAN~, X-ray diffraction （XRD）, and mineral chemistry by a scanning electron microscope equipped with an energy-dispersive spec- trometer （sEM-EDs）. The tailing sample was fine grained （69.48wt% below 45 μm size）, containing 20.25wt% Cr203 and 39.19wt% Fe203, with a Cr：Fe mass ratio of 0.51. Mineralogical investigations using QEMsCAN studies revealed that chromite, goethite, and gibbsite are the dominant mineral phases with minor amounts of hematite, kaolinite, and quartz. The sample contained 34.22wt% chromite, and chromite liberation is more than 80% for grains smaller than 250 ~tm in size. Based on these results, it was predicted that liberated chromite and high-grade middling chromite particles could be separated from the gangue by various concentration techniques. The tailing sample was beneficiated by hydrocyclone, tabling, wet high-intensity magnetic separation （WHIMs）, and flotation in order to recover the chromite. A chromite concentrate with 45.29wt% Cr203 and a Cr：Fe mass ratio of 1.85 can be produced from these low-grade chromite ore beneficiation plant rejects.

关键词： tailings mineralogy chromites beneficiation

Growth, Optical, Mechanical, Dielectric and Theoretical studies on Potassium Pentaborate Tetrahydrate (KB_5O_8·4H_2O) single Crystal by Modified sankaranarayanan-Ramasamy Method

在线全文

学校读者我要写书评

暂无评论

Journal of Materials science & Technology 2009年第6期25卷 745-748页

作者： C. Justin Raj s. Krishnan s. Dinakaran J. Mary Linet R. Uthrakumar R. Robert s. jerome das Department of Physics FET Saveetha University Department of Physics RMK Engineering College Department of Physics Loyola College

A nonlinear optical single crystal of potassium pentaborate tetrahydrate （KB5O8·4H2O） has been grown from aqueous solution by using unidirectional crystal growth method of sankaranarayanan-Ramasamy （sR） with a due modification in the growth assembly. Potassium pentaborate crystal of 60 mm length and 10 mm diameter has been grown along （100） plane with a growth rate of 3 mm per day within a period of 20 days. The grown crystal was subjected to single crystal X-ray diffraction analysis to confirm that the crystal belongs to the orthorhombic system. some fundamental data such as valance electron plasma energy, Penn gap, Fermi energy and electronic polarizability of the grown crystal were calculated. The presence of borate in the grown crystal was confirmed by Fourier transform infrared （FTIR） spectroscopy. The optical transmission property of the grown crystal was analyzed using ultra violet （UV） visible spectral analysis. surface morphology of the growth plane was observed using scanning electron microscopy （sEM）. The mechanical strength of the crystals was found out using Vickers microhardness test along the growth axis. Frequency dependent dielectric constant of the grown crystal was studied for various temperatures along （100） plane.

关键词： Crystal growth Characterization Nonlinear optic materials

A New Contraction Principle in Menger spaces

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica sinica,English series 2008年第8期24卷 1379-1386页

作者： Binayak s.CHOUDHURY Krishnapada das Department of Mathematics Bengal Engineering and Science UniversityShibpurP.O.- B.GardenShibpurHowrah- 711103West BengalINDIA

In the present work we introduce a new type of contraction mapping by using a specific function and obtain certain fixed point results in Menger spaces. The work is in line with the research for generalizing the Banach＇s contraction principle. We extend the notion of altering distance function to Menger spaces and obtain fixed point results.

关键词： Menger space φ-contraction fixed point

Magnetic and flotation studies of banded hematite quartzite (BHQ) ore for the production of pellet grade concentrate

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2010年第6期17卷 675-682页

作者： B. das B.K.Mishra s. Prakash s.K.das P.s.R.Reddy s.I.Angadi Institute of Minerals and Materials Technology Council of Scientific & Industrial Research (CSIR)

To identify and establish beneficiation techniques for banded hematite quartzite （BHQ） iron ore, a comprehensive research on BHQ ore treatment was carried out. The BHQ ore was assayed as 38.9wt% Fe, 42.5wt% siO2, and 1.0wt% Al2O3. In this ore, hematite and quartz are present as the major mineral phases where goethite, martite, and magnetite are present in small amounts. The liberation of hematite particles can be enhanced to about 82% by reducing the particle size to below 63 μm. The rejection of silica particles can be obtained by magnetic and flotation separation techniques. Overall, the BHQ ore can be enriched to 65.3wt% Fe at 61.9% iron recovery. A flowsheet has been suggested for the commercial exploitation of the BHQ ore.

关键词： hematite beneficiation magnetic separation flotation pelletizing

Recovery of rare earth metals through biosorption: An overview

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2013年第10期31卷 933-943页

作者： Nilanjana das Devlina das Bioremediation Laboratory Environmental Biotechnology Division School of Biosciences and Technology VIT University

Rare earth metals （REMs） are a series of 17 elements that have widespread and unique applications in high technology, power generation, communications, and defense industries. These resources are also pivotal to emergent sustainable energy and car- bon alternative technologies. Recovery of REMs is interesting due to its high market prices along with various industrial applications. Conventional technologies, viz. precipitation, filtration, liquid-liquid extraction, solid-liquid extraction, ion exchange, super critical extraction, electrowinning, electrorefining, electroslag ref＇ming, etc., which have been developed for the recovery of REMs, are not economically attractive. Biosorption represents a biotechnological innovation as well as a cost effective excellent tool for the recovery of rare earth metals from aqueous solutions. A variety ofbiomaterials such as algae, fungi, bacteria, resin, activated carbon, etc., have been reported to serve as potential adsorbents for the recovery of REMs. The metal binding mechanisms, as well as the parameters in- fluencing the uptake of rare earth metals and isotherm modeling are presented here. This article provides an overview of past achievements and current scenario of the biosorption studies carried out using some promising biosorbents which could serve as an economical means for recovering REMs. The experimental findings reported by different workers will provide insights into this re- search frontier.

关键词： biosorption biosorbent desorption rare earth metals recovery

COMPUTATION OF RETURN FLOWs DUE TO NAVIGATION TRAFFICs IN REsTRICTED WATERWAYs

在线全文

学校读者我要写书评

暂无评论

International Journal of sediment Research 2006年第4期21卷 249-260页

作者： B. s. MAZUMDER s. K. das s. N. das Indian statistical Institute Kolkata-700 108 IndiaProf. International Institute of Information Technology Pune India Prof. Assis. Res. Officer Central Water and Power Research Station Pune-411 024 India

The paper deals with the development of an empirical model to compute the return flow due to the movement of navigation traffics in restricted waterway when the speed of the navigation traffic is under sub-critical range. The velocity profile of the return flow is modelled, where the functional dependence with respect to ambient flow, principal dimensions of the vessel, wetted cross-sectional area of the river, width and average depth of the river, and the lateral distance of the vessel from the bank are implicitly considered. This model has been validated with the observed data collected from the four specific sites, such as Kampsville, Apple River Island, Goose Island and Clarks Ferry of Illinois River during barge-tow movement. The present model shows significant improvement of return flow prediction in comparison to earlier empirical results. This model has also the ability to determine the locus of zero velocity point.

关键词： Return flow Navigation traffic Empirical model Restricted waterway Barge-tow Zero velocity point Froude number

Pressure Drop of Non-Newtonian Liquid Flow Through Elbows

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2000年第4期8卷 388-390页

作者： T.K.Banerjee s.K.das Chemical Engineering Department University of Calcutta92A.P.C.RoadCalcutta-700 009IndiaChemical Engineering DepartmentUniversity of Calcutta92A.P.C.RoadCalcutta-700 009India

Experimental data on the pressure drop across different types of elbow for non-Newtonian pseudoplastic liquid flow in laminar condition have been presented. A generalized correlation has been developed for predicting ... 详细信息

关键词： non-Newtonian liquid pseudoplastic elbow

Optimization of flotation variables for the recovery of hematite particles from BHQ ore

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7期20卷 605-611页

作者： swagat s. Rath Hrushikesh sahoo B. das CsIR-Institute of Minerals and Materials Technology Bhubaneswar 751 013 India

The technology for beneficiation of banded iron ores containing low iron value is a challenging task due to increasing demand of quality iron ore in India. A flotation process has been developed to treat one such ore, namely banded hematite quartzite （BHQ） containing 41.8wt% Fe and 41.5wt% siO2,by using oleic acid, methyl isobutyl carbinol （MIBC）, and sodium silicate as the collector, frother, and dispersant, respectively. The relative effects of these variables have been evaluated in half-normal plots and Pareto charts using central composite rotatable design. A quadratic response model has been developed for both Fe grade and recovery and optimized within the experimental range. The optimum reagent dosages are found to be as follows： collector concentration of 243.58 g/t, dispersant concentration of 195.67 g/t, pH 8.69, and conditioning time of 4.8 min to achieve the maximum Fe grade of 64.25% with 67.33% recovery. The predictions of the model with regard to iron grade and recovery are in good agreement with the experimental results.

关键词： hematite iron ore treatment flotation metal recovery design of experiments mathematical models opti-mization