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Journal of Environmental Sciences 2017年第2期29卷 160-169页

作者： Raja Kumar alok Sinha Department of Environmental Science&Engineering Indian School of MinesDhanbad 826004JharkhandIndia

Influence of common dye-bath additives, namely sodium chloride, ammonium sulphate,urea, acetic acid and citric acid, on the reductive decolouration of Direct Green 1 dye in the presence of Fe0 was investigated. Organic acids improved dye reduction by augmenting Fe0 corrosion, with acetic acid performing better than citric acid. Na Cl enhanced the reduction rate by its ‘salting out’ effect on the bulk solution and by Cl-anion-mediated pitting corrosion of iron surface.（NH4）2SO4induced ‘salting out’ effect accompanied by enhanced iron corrosion by SO42-anion and buffering effect of NH4＋ improved the reduction ***, at 2 g/L（NH4）2SO4concentration, complexating of SO42-with iron oxides decreased Fe0 reactivity. Urea severely compromised the reduction reaction, onus to its chaotropic and‘salting in’ effect in solution, and due to it masking the Fe0 surface. Decolouration obeyed biphasic reduction kinetics（R2〉 0.993 in all the cases） exhibiting an initial rapid phase,when more than 95% dye reduction was observed, preceding a tedious phase. Maximum rapid phase reduction rate of 0.955/min was observed at p H 2 in the co-presence of all dye-bath constituents. The developed biphasic model reckoned the influence of each dye-bath additive on decolouration and simulated well with the experimental data obtained at pH 2.

关键词： Biphasic kinetics/model Direct Green 1 Dye-bath additives Fe0

Production and characterisation of new bioresorbable radiopaque Mg–Zn–Y alloy to improve X-ray visibility of polymeric scaffolds

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Journal of Magnesium and Alloys 2022年第6期10卷 1694-1703页

作者： alok Srivastava Naresh Bhatnagar Mechanical Engineering Department Indian Institute of TechnologyDelhiIndia

For the medical diagnosis,radiopaque materials(RM)made from high specific gravity elements like Pt,Au,Ta,Iodine,Bromine are either attached or blended or coated on an implant to makes it detectable under X-ray/Fluoroscopy/*** facilitate the surgeon in an operation theatre to position an implant during the ***,RM are non-degradable,thus in case of biodegradable implants,it may detach from the body and accumulate in vital organ cause serious health ***,a new bioresorbable radiopaque material(BRM)was produced by alloying the high specific gravity elements Zn(35%w/w)and Y(4%w/w)with Mg *** this alloy,three main phases were identified,alpha Mg,Mg_(7)Zn_(3)and icosahedral quasicrystalline I-phase Mg3Zn6Y,which reinforce the Mg ***,BRM was powdered to a size of less than 25 microns and blended in different ratios with bioresorbable poly-L-lactic acid(PLLA)for fabricating PLLA/BRM *** microparticles were uniformly distributed and interfacial bonded with the *** X-ray was passed through bio-composite to captureμCT radiograph for evaluating linear attenuation co-efficient(μ)and optical density(OD).Thermal analysis reveals that BRM particles act as a nucleating site and enhance the crystallinity of the polymeric *** the In Vitro accelerated degradation study,the alkaline nature of BRM neutralise the acidity of PLLA and balance the pH of the body fluid to reduce the inflammatory reactions,but this compromises the stability of the polymer as it increases the decomposition rate.

关键词： Magnesium alloys X-ray Quasicrystal Polymer matrix composites Radiopacity

Modelling and analysis of COVID-19 epidemic in India

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Journal of Safety Science and Resilience 2020年第2期1卷 135-140页

作者： alok Tiwari Department of Energy Science and Engineering IIT BombayMumbai 400076India

COVID-19 epidemic is declared as the public health emergency of international concern by the World Health Organisation in the last week of March *** disease originated from China in December 2019 has already caused havoc around the world,including *** first case in India was reported on 30th January 2020,with the cases crossing 4 million on the day paper was *** pandemic has caused more than 80,000 fatalities with 3 million *** lockdown of the nation for two months,immediate isolation of infected cases and app-based tracing of infected are some of the proactive steps taken by the *** a better understanding of the evolution of COVID-19 in the world,study on evolution and growth of cases in India could not be *** understand the same,one of the compartment model:Susceptible-Infectious-Quarantined-Recovered(SIQR)is *** rate and doubling rate of the total reported positive cases in the country had crossed 75%and 25 days,*** is also estimated that there is a strong positive correlation between testing rate and detection of new cases up to 6 million tests per *** the SIQR modelling effective reproduction number,epidemic doubling rate and infected to quarantined ratio is determined to check the temporal evolution of the pandemic in the *** reproduction number that was at its peak during first half of the April is gradually converging to *** is also estimated using this model that with each detected cases in India,there could be 10-50 undetected *** every mathematical model,this model also has some *** make this model more robust,a technique with weighted parameter that can avoid a person with a strong immune system to be equally vulnerable to the infection,can be worked *** learning algorithms can also be used to train our model with the data of other countries to make the analysis and prediction more precise and accurate.

关键词： Mathematical modelling SIQR COVID 19 Reproduction number India

Acclimation and Tolerance Strategies of Rice under Drought Stress

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Rice science 2015年第4期22卷 147-161页

作者： Veena PANDEY alok SHUKLA Department of Plant Physiology College of Basic Sciences and HumanitiesGovind Ballabh Pant University of Agriculture & Technology

Rice （Oryza sativa L.） is an important food crop and requires larger amount of water throughout its life cycle as compared to other crops. Hence, water related stress cause severe threat to rice production. Drought is a major challenge limiting rice production. It affects rice at morphological （reduced germination, plant height, plant biomass, number of tillers, various root and leaf traits）, physiological （reduced photosynthesis, transpiration, stomatal conductance, water use efficiency, relative water content, chlorophyll content, photosystem II activity, membrane stability, carbon isotope discrimination and abscisic acid content）, biochemical （accumulation of osmoprotectant like proline, sugars, polyamines and antioxidants） and molecular （altered expression of genes which encode transcription factors and defence related proteins） levels and thereby affects its yield. To facilitate the selection or development of drought tolerant rice varieties, a thorough understanding of the various mechanisms that govern the yield of rice under water stress condition is a prerequisite. Thus, this review is focused mainly on recent information about the effects of drought on rice, rice responses as well as adaptation mechanisms to drought stress.

关键词： rice water drought stress yield attribute morphological characteristic physiological characteristic biochemical characteristic molecular level

Dual-Core Photonic Crystal Fiber Plasmonic Refractive Index Sensor: A Numerical Analysis

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Photonic Sensors 2019年第2期9卷 151-161页

作者： alok Kumar PAUL Ajay Krishno SARKAR Department of Electrical & Electronic Engineering Rajshahi University of Engineering & Technology Rajshahi-6204 Bangladesh

A numerical analysis on dual core photonic crystal fiber (DC-PCF) based surface plasmon resonance (SPR) refractive index sensor is presented. The guiding parameters and required sensing performances are examined with finite element method (FEM) based software under MATLAB environment. According to simulation, it is warranted that the proposed refractive index sensor offers the maximum amplitude sensitivity of 554.9 refractive index unit (RIU-1) and 636.5 RIU 1 with the maximum wavelength sensitivity of 5800nm/RIU and 11 500nm/RIU, and the sensor resolutions of 1.72 ×10^-5RIU and 8.7× 10^-6 RIU, at analyte refractive index (RI) of 1.40 for x- and y-polarized modes, respectively. As the sensing performance in different wavelength ranges is quite high, the proposed sensor can be used in simultaneous detection for different wavelength ranges. Therefore, the proposed device is of a suitable platform for detecting biological, chemical, biochemical, and organic chemical analytes.

关键词： Photonic crystal fiber biosensor refractive index sensor finite element method plasmonic material

Ion Conduction in Superionic Glassy Electrolytes:An Overview

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Journal of Materials Science & Technology 2013年第3期29卷 193-208页

作者： Angesh Chandra alok Bhatt Archana Chandra Department of Applied Physics Shri Shankaracharya Institute of Prof.Manag.& Tech.Raipur 492015C.G.India Department of Applied Physics M.P Christian College of Engg.& Tech.Bhilai 490026C.G.India

The various theoretical and experimental models for ion conduction mechanism of fast ion conducting （FIC） glass electrolytes have been reported in the present review paper. Some characterization techniques of FIC glasses are presented. The experimental methods for determination of some ion transport parameters viz ionic conductivity （σ）, ionic mobility （μ）, mobile ion concentration （n）, ionic drift velocity （Vd）, ionic transference number （tion） and activation energies of FIC glasses are explained. The solid state battery fabrication by using some FIC glasses is also reported.

关键词： Ion conduction Glassy solid electrolyte Fast ion conducting (FIC) glass Superionic solid Relaxation phenomenon

Powder mixed electrochemical discharge process for micro machining of C103 niobium alloy

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Defence Technology（防务技术） 2023年第8期26卷 84-101页

作者： Niladri Mandal Nitesh Kumar alok Kumar Das Defence Research&Development Laboratory(DRDL)-DRDO HyderabadIndia Department of Mechanical Engineering Indian Institute of Technology(ISM)DhanbadIndia

This work demonstrates the viability of the powder-mixed micro-electrochemical discharge machining(PMECDM) process to fabricate micro-holes on C103 niobium-based alloy for high temperature *** processes are involved simultaneously *** erosion,chemical etching,and abrasive grinding for removal of material while the classical electrochemical discharge machining process involves double actions *** erosion,and chemical *** powder-mixed electrolyte process resulted in rapid material removal along with a better surface finish as compared to the classical microelectrochemical discharge machining(MECDM).Further,the results are optimized through a multiobjective optimization approach and study of the surface topography of the hole wall surface obtained at optimized *** the selected range of experimental parameters,PMECDM shows a higher material removal rate(MRR) and lower surface roughness(R_(a))(MRR:2.8 mg/min and R_(a) of 0.61 μm) as compared to the MECDM process(MRR:2.01 mg/min and corresponding Raof 1.11 μm).A detailed analysis of the results is presented in this paper.

关键词： Micro-electrochemical discharge machining C103 niobium alloy Surface integrity Material removal rate Hybrid powder mixed ECDM

Study of damage behavior and repair eff ectiveness of patch repaired carbon fi ber laminate under quasi-static indentation loading

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Petrographic characterization and evolution of the Karharbari coals, Talcher Coalfield, Orissa, India

Defence technology 2024年第4期 29页

作者： alok Kumar Chinmaya Kumar Sahoo A.Arockiarajan

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International Journal of Coal Science & Technology 2016年第2期3卷 133-147页

作者： alok K. Singh Rajiv Gandhi Institute of Petroleum Technology RatapurChowk Rae Bareli 229316 India

In the present study an attempt has been made to carry out the detailed petrographic characterization of the Karharbari coals of Talcher coalfield and to reconstruct the paleoenvironment conditions of coal formation using macerals and microlithtotypes as a tool. For these purposes a large number of samples were collected following the pillar sampling method and were subjected to detailed petrographic study. The petrographic observation shows that these coals are vitrinite rich followed by the liptinite and inertinite group of macerals. On microlithotype scale, these coals shows the dominance of the vitrite followed by clarite, vitrinertite and inertite. The concentration of liptite, clarodurite, duroclarite and vitriner- toliptite are insignificant. The vitrinite reflectance ranks the Karharbari coal as high volatile bituminous ＇C＇ to high volatile ＇B＇ bituminous. Coal petrography based depositional models suggest peat accumulation in forested telmatic swamp. Moreover, during the time of their evolution, there were alternate phases of oxic and anoxic moor conditions with good tissue preservation.

关键词： Petrography Rank Evolution - Karharbari Talcher coalfield

Optimal ordering policy for short life-cycle products under credit financing with dynamic adoption in supply chain

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Journal of Management Analytics 2019年第3期6卷 269-301页

作者： Udayan Chanda alok Kumar Department of Management BITS PilaniPilaniIndia FORE School of Management New DelhiIndia

Traditional inventory models are mostly ignorant of the life cycle dynamics of a technology product;hence,they often fail to identify different dimensions of inventory *** paper attempts to investigate the relationship between adoption behavior of customers using life cycle dynamics and associated trade credit policies in order to optimize the total inventory *** demand model used in this paper treats sales as a function of awareness diffusion and *** is considered as a function of feedback effects from users/***’s optimal strategies for short life cycle product under credit financing were determined ***,numerical examples have been used to support the theoretical *** results have further been used to gain some managerial insights.

关键词： inventory stage-wise diffusion unfavorable information short life cycle trade credit