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Interfacial instability of sand patterns induced by turbulent shear flow

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International Journal of Sediment Research 2021年第4期36卷 449-456页

作者： Sk Zeeshan Ali Subhasish dey Department of Civil Engineering Indian Institute of Technology Hyderabad Department of Civil Engineering Indian Institute of Technology Kharagpur Department of Hydraulic Engineering State Key Laboratory of Hydro-Science and Engineering Tsinghua University

When a turbulent shear flow above a plane sand surface entrains sand grains, it generates a variety of sand patterns. Fluvial sand forms two major interfacial patterns: meso-scale dunes and antidunes, and large-scale bars. Measurements have evidenced that under erosive conditions, meso-scale patterns either change to or coexist with large-scale patterns. However, it remains elusive what exactly drives the switching of interfacial patterns and how the switching occurs. Here, we showdcombing a flow model with a grain transport model, allowing for both the surface and suspended sand fluxes dthat the switching of patterns emerges from the shear-driven complex feedback between grain transport and topographic perturbations. The switching predominantly depends on the magnitudes of the Rouse number and the grain size to undisturbed flow depth ratio. The model offers quantitative predictions of the maximum amplification of sand patterns and unveils a new attraction erepulsion phenomenon.

关键词： Instability Sand patterns Turbulent flow Sediment transport

Synthesis of Mg(OH)_(2) micro/nano flowers at room temperature

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Journal of Advanced Ceramics 2013年第2期2卷 173-179页

作者： Pradip Sekhar DAS Arjun dey Ashok Kumar MANDAL Nitai dey Anoop K.MUKHOPADHYAY CSIR-Central Glass and Ceramic Research Institute Kolkata 700032India Thermal Systems Group ISRO Satellite CentreVimanapura PostBangalore 560017India

The inexpensive and green method of synthesis for self-assembled micro/nano structures is an important area of emerging *** structures can be chemically tuned with predesigned functional ***,they hold very good promise for future applications,e.g.,biomedicine,electronic device,solar energy,gas *** we report for the first time an inexpensive and green method for chemical deposition of magnesium hydroxide(Mg(OH)_(2))micro/nano flowers in thin films on commercial soda lime silica glass substrates at room *** identical conditions,chemically synthesized Mg(OH)_(2) powders are also prepared in absence of the soda lime silica glass *** condition that favors the growth of micro/nano flowers in thin films is identified from X-ray diffraction(XRD),scanning electron microscopy(SEM),field emission scanning electron microscopy(FE-SEM),transmission electron microscopy(TEM),and energy dispersive X-ray spectroscopy(EDX)***,the possible growth mechanism of micro/nano flowers in thin films is discussed.

关键词： magnesium hydroxide(Mg(OH)2) flower-like microstructure chemical deposition film

Morphological and Microstructural Evidences of Paleo-Seisminc Occurrences in an Earthquake Prone Zone of Tripura, India

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Journal of Earth Science 2014年第2期25卷 289-298页

作者： Sudip dey Sushmita Paul Prasamita Sarkar Department of Geography and Disaster Management Tripura University

Morphology and structure of a faulted zone not only express the present status but also preserve the evidences of early seismo-tectonic occurrences. The present paper aims to assess the morphological as well as subsurface evidences of early seismo-tectonic occurrences in an earth- quake prone zone of Baromura Hill, Tripura. Tectonically this is a part of Tripura-Mizoram fold belt and fall within Zone V of BIS seismic map. In the present research the tectonic lineaments of Baromura Hill was identified by using satellite data. For that purpose, Landsat TM shortwave in- frared, midwave infrared and near infrared was selected for preparing suitable band combination. A classified thermal infrared was used for final operation. From the remote sensing operation five clear tectonic lineaments were found. During the field work rock samples were collected for labora- tory testing. Thin sections of the rocks show that complex stress pattern was developed during the geological past which caused strong seismo-tectonic occurrences. From the study it can be assessed that though the nature of the paleo-seismic occurrences were almost same but the level of impact varied through spatial and temporal scales due different physical properties and arrangements. It is also clear from the study that the geological evolution of this place is more complex as it seems to be. Tectonic and geomorphic processes worked together through the Tertiary and Quaternary periods and played equally important role for landform evolution.

关键词： morphology tectonic lineament microstructure grain scale deformation Baromura Hill geomorphic process.

Algorithmic approaches for optimizing electronic control unit time using multi-rate sampling

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Control Theory and Technology 2018年第3期16卷 173-190页

作者： Rajorshee RAHA Pallab DASGUPTA Soumyajit dey Department of Computer Science and Engineering Indian Institute of Technology Kharagpur India

With the emerging migration of automotive and other distributed control platforms from federated to integrated architectures, the need for optimal utilization of ECU （electronic control unit） bandwidth will become a key requirement in the implementation of embedded control features. This paper advocates the partitioning of the operating space of the plant and the use of minimal sampling rates in each partition without compromising the overall quality of control. At the heart of the proposed methodology are our algorithms that enable the choice of the partitions and the sampling rate for each partition. We demonstrate the efficacy of our methods on two case studies, namely an anti-lock braking system and a lane departure warning system. We also study the use of a supervisory controller that controls the switching among sampling rates for a combination of the two features.

关键词： Sampling period adaptive control stability automotive software embedded control system

Chromium-induced membrane damage: protective role of ascorbic acid

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Journal of Environmental Sciences 2001年第3期13卷 272-275页

作者： Sankar Kumar dey Prasunpriya Nayak Somenath Roy Department of Human Physiology with Community Health Vidyasagar UniversityMidnapore 721102West BengalIndia

Importance of chromium as environmental toxicant is largely due to impact on the body to produce cellular toxicity. The impact of chromium and their supplementation with ascorbic acid was studied on plasma membrane of liver and kidney in male Wistar rats (80-100g body weight). It has been observed that the intoxication with chromium (i.p.) at the dose of 0.8 mg/100g body weight per day for a period of 28 days causes significant increase in the level of cholesterol and decrease in the level of phospholipid of both liver and kidney. The alkaline phosphatase, total ATPase and Na\++\|K\++\|ATPase activities were significantly decreased in both liver and kidney after chromium treatment, except total ATPase activity of kidney. It is suggested that chromium exposure at the present dose and duration induce for the alterations of structure and function of both liver and kidney plasma membrane. Ascorbic acid (i.p. at the dose of 0.5 mg/100g body weight per day for period of 28 days) supplementation can reduce these structural changes in the plasma membrane of liver and kidney. But the functional changes can not be completely replenished by the ascorbic acid supplementation in response to chromium exposure. So it is also suggested that ascorbic acid (nutritional antioxidant) is useful free radical scavenger to restrain the chromium induced membrane damage.

关键词： chromium liver kidney membrane ascorbic acid

Petrogenesis of Two Types of Archean TTGs in the North China Craton:A Case Study of Intercalated TTGs in Lushan and Non-intercalated TTGs in Hengshan

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Acta Geologica Sinica(English Edition) 2016年第6期90卷 2049-2065页

作者： SHAN Houxiang ZHAI Mingguo dey Sukanta State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China University of Chinese Academy of Sciences Beijing 100049China Department of Applied Geology Indian School of MinesDhanbad 826004India

TTG （Tonalite-Trondhjemite-Granodiorite） gneisses, a major component of Precambrian continental crust, play a significant role in understanding the process and mechanism of the crustal evolution in the early periods of the Earth. In terms of field occurrence, there are two kinds of Archean TTGs in the NCC （North China Craton）： intercalated and non-intercalated TTGs. In this contribution, we make a comprehensive comparison of these two types of TTGs from the typical areas （Lushan and Hengshan） in the NCC with an aim to constrain their petrogenesis. The results suggest that they have similar mineral assemblages of Pl ＋ Qtz ＋ Bt ± Amp ± Kfs but different field appearances and geochemical compositions, thus probably reflecting different source materials and tectonic settings. Differences in the contents of characteristic elements, such as Sr, REE and HFSE, suggest that the non-intercalated TTGs in Hengshan were generated at deeper levels than those of intercalated TTGs in Lushan. Constraints from element contents and geochemical modeling results are consistent with derivation from dual sources involving both garnet amphibolite and rutile-bearing eclogite residues for the non-intercalated TTGs in Hengshan, whereas the compositions of intercalated TTGs in Lushan indicate that they were formed by partial melting with amphibolite to garnet-amphibolite residues. Moreover, accumulation of plagioclase is also required in the petrogenesis of intercalated TTGs in Lushan, at least for part of them. In addition, the non-intercalated TTGs in Hengshan display distinctly higher MgO, Mg#, Cr and Ni values and lower SiO2 average contents compared to the intercalated TTGs in Lushan. These features suggest that the former magma, at least a part, might have interacted with the mantle wedge during ascent. Considering all the above factors and in combination with the whole-rock Nd and zircon Hf isotopic data, it is suggested that the non-intercalated TTGs in Hengshan were produced by partia

关键词： TTGs petrogenesis crustal growth Archean North China Craton

Oxygen Functionalization-Induced Charging Effect on Boron Active Sites for High-Yield Electrocatalytic NH_(3) Production

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Nano-Micro Letters 2022年第12期14卷 464-480页

作者： Ashmita Biswas Samadhan Kapse Ranjit Thapa Ramendra Sundar dey Institute of Nano Science and Technology(INST) Sector-81MohaliPunjab 140306India Department of Physics SRM University-APAmaravatiAndhra Pradesh 522240India

Ammonia has been recognized as the future renewable energy fuel because of its wide-ranging applications in H_(2) storage and transportation *** order to avoid the environmentally hazardous Haber-Bosch process,recently,the third-generation ambient ammonia synthesis has drawn phenom-enal attention and thus tremendous efforts are devoted to developing efficient electrocatalysts that would circumvent the bottlenecks of the electrochemical nitrogen reduction reaction(NRR)like competitive hydrogen evolution reac-tion,poor selectivity of N_(2) on catalyst ***,we report the synthesis of an oxygen-functionalized boron carbonitride matrix via a two-step pyrolysis *** conductive BNCO(1000)architecture,the compatibility of B-2p_(z) orbital with the N-2p_(z) orbital and the charging effect over B due to the C and O edge-atoms in a pentagon altogether facilitate N_(2) adsorption on the B edge-active *** optimum electrolyte acidity with 0.1 M HCl and the lowered anion crowding effect aid the protonation steps of NRR via an associative alternating pathway,which gives a sufficiently high yield of ammonia(211.5μg h^(−1) mg_(cat)^(−1))on the optimized BNCO(1000)catalyst with a Faradaic efficiency of 34.7%at−0.1 V vs *** work thus offers a cost-effective electrode material and provides a contemporary idea about reinforcing the charging effect over the secured active sites for NRR by selectively choosing the electrolyte anions and functionalizing the active edges of the BNCO(1000)catalyst.

关键词： C-doped boron nitride O-functionalization Density-functional theory(DFT) Charging effect Nitrogen reduction reaction Ambient ammonia synthesis

Alpha-tocopherol supplementation on chromium toxicity: a study on rat liver and kidney cell membrane

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Journal of Environmental Sciences 2003年第3期15卷 356-359页

作者： Sankar Kumar dey Prasunpriya Nayak Somenath Roy Department of Human Physiology with Community Health Vidyasagar UniversityDepartment of Human Physiology with Community Health Vidyasagar UniversityDepartment of Human Physiology with Community Health Vidyasagar University Midnapore-721 102 West Bengal IndiaMidnapore-721 102 West Bengal IndiaMidnapore-721 102 West Bengal India

Membrane damage is one of the important consequence of chromium, an environmental toxicant, to produce cytotoxicity. α-tocopherol, a membrane protectant can be used to reduce the chromium-induced membrane damage. In the present study, the impact of chromium in presence and absence of α-tocopherol was studied on plasma membrane of liver and kidney in male Wistar rats (80—100 g body weight). Significant increase in membrane cholesterol level as well as significant decrease in membrane phospholipid level in chromium exposed ( 0.8 mg /100 g body weight/d, i.p., for 4 weeks) animals suggest structural alteration of both liver and kidney plasma memebrane. The alkaline phosphatase, total ATPase and Na +-K +-ATPase activities of plasma membrane were significantly decreased in both liver and kidney after chromium treatment. However, α-tocopherol (30 mg/100 g diet) supplementation can restrict the changes in these membrane-bound enzyme activities. Thus, the usefulness of dietary supplementation of α-tocopherol to restrain the chromium-induced membrane damage is suggested.

关键词： chromium liver kidney membrane α-tocopherol

Demand side management for solving environment constrained economic dispatch of a microgrid system using hybrid MGWOSCACSA algorithm

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CAAI Transactions on Intelligence Technology 2022年第2期7卷 256-267页

作者： Sourav Basak Bishwajit dey Biplab Bhattacharyya Department of Electrical Engineering Indian Institute of Technology(Indian School of Mines)DhanbadIndia Department of Electrical and Electronics Engineering Gandhi Institute of Engineering and TechnologyGunupurOdishaIndia

Microgrids are a type of restricted power distribution systems in which electricity is generated,transmitted,and distributed within a small geographic *** are used to ensure that renewable energy sources are used to their full *** provide further benefits,such as lowering transmission losses and the expenses associated with *** research compares and contrasts the aims of economic dispatch,emission dispatch,fractional programing based combined economic emission dispatch,and environmental restricted economic dispatch(ECED).A low-voltage microgrid system is investigated for three different *** a study optimization tool,an innovative,resilient,and strong hybrid swarm-intelligence optimization algorithm is utilised,which is based on combining the properties of the traditional grey-wolf optimiser,sine-cosine algorithm,and crow search *** employment of a time-of-use energy mar-ket pricing approach instead of a fixed pricing plan resulted in a 15%decrease in gen-eration costs throughout the course of the *** ECED was assessed with a 15%-20%demand side management based restructured load demand model for the microgrid system,the generation costs were reduced even further.

关键词： demand side management energy management MGWOSCACSA microgrid