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Rayleigh-type wave propagation through liquid layer over corrugated substrate

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Applied Mathematics and Mechanics(English Edition) 2017年第6期38卷 851-866页

作者： A.k.SINGH A.das A.RAY Department of Applied Mathematics Indian Institute of Technology(ISM)

The propagation of the Rayleigh-type wave in a fluid layer overlying a corrugated substrate is studied. The corrugated substrate is considered as a fluid satu- rated poroelastic substrate and a quadratically heterogeneous isotropic elastic substrate in Case I and Case II, respectively. Closed form expressions of dispersion relation for Case I and Case II ave obtained. The influence of corrugation, porosity, and hetero- geneity on the phase velocity of Rayleigh-type wave, for both cases, is highlighted and demonstrated through numerical computation and graphical discussion. Neglecting cor- rugation at the common interface, expressions of phase velocity of the Rayleigh-type wave for both cases ave derived in a closed form as a special case of the problem. Comparison between the presence and the absence of both heterogeneity and poroelasticity in the substrate of the composite structure is a k.y in the present study.

关键词： Rayleigh-type wave porosity heterogeneity corrugation

A survey on control issues in renewable energy integration and microgrid

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Protection and Control of Modern Power Systems 2019年第1期4卷 89-115页

作者： Faisal R.Badal Purnima das Subrata k.Sark.r Sajal k.das Department of Mechatronics Engineering Rajshahi University of Engineering and TechnologyKajlaRajshahi-6204Bangladesh

This paper describes the usefulness of renewable energy throughout the world to generate power. Renewable energy adds a remark.ble scope in power system. Renewable energy sources act as the prime mover of a microgrid. The Microgrid is a small network.of power system with distributed generation (DG) units connected in parallel. The integration challenges of renewable energy sources and the control of microgrid are described in this paper. The varied nature of DG system produces voltage and frequency deviation. The unk.own nature of the load produces un-modeled dynamics. This un-modeled dynamic introduces measurable effects on the performance of the microgrid. This paper investigates the performance of the microgrid against different scenarios. The voltage of the microgrid is controlled by using different controllers and their results are also investigated. The performance of controllers is investigated using MATLAB/Simulink.SimPowerSystems.

关键词： Renewable energy Integral challenges Microgrid Control process Voltage control

Einstein Energy-Momentum Complex for a Phantom Black.Hole Metric

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Chinese Physics Letters 2015年第2期32卷 19-22页

作者： P. k. Sahoo k. L. Mahanta D. Goit A. k. Sinha S. S. Xulu U. R. das A. Prasad R. Prasad Department of Mathematics Birla Institute of Technology and Science-Pilani Hyderabad Campus Hyderabad 500078 India Department of Mathematics C. V. Raman College of Engineering Bhubaneswar 752054 India Department of Physics B.S. College Patna 800012 India Department of Physics College of Commerce Patna 800020 India Department of Computer Science University of Zululand Kwa-Dlangezwa 3886 South Africa Department of Physics D.N. College Patna 804452 India Department of Physics L.S. College Muzaffarpur 842001 India

We calculate the energy distribution associated with a static spherically symmetric non-singular phantom black.hole metric in Einstein＇s prescription in general relativity. As required for the Einstein energy-momentum complex, we perform the calculations in quasi-Cartesian coordinates. We also calculate the momentum components and obtain a zero value, as expected from the geometry of the metric.

关键词： Einstein Energy-Momentum Complex for a Phantom Black.Hole Metric FRW

MXene-based nanomaterials as adsorbents for wastewater treatment:a review on recent trends

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Frontiers of Materials Science 2022年第1期16卷 55-70页

作者： Rajesh k.JENA Himadri Tanaya das Braja N.PATRA Nigamananda das Centre of Excellence in Advanced Materials and Applications Utkal UniversityVani ViharBhubaneswar 751004India Department of Chemistry Utkal UniversityVani ViharBhubaneswar 751004India

The wastewater treatment is a challenging research area to reduce the increasing pressure on limited fresh water *** several techniques adopted and practiced,adsorption is one of the most effective and sustainable ecofriendly *** recent years,MXene nanomaterials,a new family of transition metal carbides,have gained increasing attention as the potential adsorbent for pollutants due to their unique features such as large surface area with abundant active sites and hydrophilicity.A wide range of pollutants *** metal ions,organic dyes,radionuclides,and toxic gas molecules have been sensed by 2D *** inclusive understanding on the adsorptive behavior of MXene-based materials is needed to explain the removal mechanism and effects of different adsorption *** review gives a general overview on recent research progress on MXene materials with special reference to their applications for the adsorptive removal of different *** general trends in the synthesis of MXenes,their stability and different factors affecting the adsorption process along with the main challenges in understanding the full potential of MXenes for environmental applications are discussed.

关键词： MXene adsorption wastewater treatment heavy metal radionuclide

Major　ion　chemistry　and　control　of　weathering　of　Bhimtal　Lak.，Humaun　Himalaya，India

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Journal of Environmental Sciences 1996年第3期8卷 367-377页

作者： Manpreet Singh B. k. das (Centre of Advanced Study in Geology), Panjab University, Chandigarh-160 014, India Centre of Advanced Study in Geology Panjab University Chandigarh-160 014 India

The water chemistry of Bhimtal Lak. revealed the dominance of Ca￣(2+) and HCO_3￣- *** lak. water chemistry is controlled by the dominance of Ca-Mg silicate weathering(mainly pumpellyite and epidote-bearing rock.) supported by anthropogenic activity involving extensive road cutting and house holding activities, increased industrialization in the catchment area of the lak.. On the basis of phosphate values. a transitional mesotrophic-eutrophic conditions exist in this *** observed chemical data of the Bhimtal Lak. was used to predict the mineral assemblages in the carbonate and alumino-silicate system. It demonstrates that the calcite and dolomite are the possible minerals which are in equilibrium with the lak. water system and that the lak. water is in the range of stability of k.olinite.

关键词： Bhitmal anthropogenic carbon dioxide pressure photosynthesis silicate weathering.

Microstructure studies of air-plasma-spray-deposited CoNiCrAlY coatings before and after thermal cyclic loading for high-temperature application

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International Journal of Minerals,Metallurgy and Materials 2016年第8期23卷 934-942页

作者： Dipak.k.mar k.N.Pandey Dipak.k.mar das Mechanical Engineering Department Motilal Nehru National Institute of TechnologyAllahabad-211004India Defense Metallurgical Research Laboratory Hyderabad-500058India

In the present study, bond-coats for thermal barrier coatings were deposited via air plasma spraying（APS） techniques onto Inconel 800 and Hastelloy C-276 alloy substrates. Scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, X-ray diffraction（XRD）, and atomic force microscopy（AFM） were used to investigate the phases and microstructure of the as-sprayed, APS-deposited Co Ni Cr Al Y bond-coatings. The aim of this work.was to study the suitability of the bond-coat materials for high temperature applications. Confirmation of nanoscale grains of the γ/γ′-phase was obtained by TEM, high-resolution TEM, and AFM. We concluded that these changes result from the plastic deformation of the bond-coat during the deposition, resulting in Co Ni Cr Al Y bond-coatings with excellent thermal cyclic resistance suitable for use in high-temperature applications. Cyclic oxidative stability was observed to also depend on the underlying metallic alloy substrate.

关键词： thermal barrier coatings coating structure plasma spraying thermal cycle high-temperature applications microstructure studies

Effects of T6 heat treatment on mechanical, abrasive and erosive-corrosive wear properties of eutectic Al-Si alloy

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Transactions of Nonferrous Metals Society of China 2012年第5期22卷 1041-1050页

作者： A. k. GUPTA B. k. PRASAD R. k. PAJNOO S. das CSIR - Advanced Materials and Processes Research Institute Bhopal-462026 India Central Institute of Agricultural Engineering (ICAR) Bhopal-462028 India

The abrasive and erosive-corrosive properties of eutectic Al-Si （LM6） alloy were studied. Microstructural features of the alloy were altered by controlling the T6 heat treatment parameter, and their influence on hardness, strength and elongation, and response of the samples in erosion-corrosion and abrasion conditions were studied. Characteristics of the Al-Si alloy samples were compared with those of Al conventionally used in agricultural machineries. Fabrication of a typical component using the Al-Si alloy was also explored in order to understand the feasibility of using the alloy system for the envisaged applications. The study suggests the response of the samples in different conditions to be greatly influenced by parameters lik. chemical composition, microstructural features and applied load, traversal distance and test environment. The performance of even the as cast Al-Si alloy is far superior to that of the conventional Al samples, while the T6 heat treated Al-Si alloy shows improved performance. Accordingly, the as-cast as well as T6 heat treated Al-Si alloy has potential for applications in agriculture as a replacement for the conventionally used Al.

关键词： Al-Si alloy heat treatment abrasion erosion corrosion

Oscillatory Shannon entropy in the process of equilibration of nonequilibrium crystalline systems

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Chinese Physics B 2015年第8期24卷 658-661页

作者： A.Giri Nilangshu k.das P.Barat Variable Energy Cyclotron Centre 1/AF Bidhannagar Indira Gandhi Centre for Atomic Research

We present a study of the equilibration process of some nonequilibrium crystalline systems by means of molecular dynamics simulation technique. The nonequilibrium conditions are achieved in the systems by randomly defining velocity components of the constituent atoms. The calculated Shannon entropy from the probability distribution of the k.netic energy among the atoms at different instants during the process of equilibration shows oscillation as the system relaxes towards equilibrium. Fourier transformations of these oscillating Shannon entropies reveal the existence of Debye frequency of the concerned system.

关键词： entropy and other measures of information nonequilibrium and irreversible thermodynamics

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

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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. Prak.sh 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