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Understanding arsenic behavior in alluvial aquifers:Evidence from sediment geochemistry,solute chemistry and environmental isotopes

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Geoscience Frontiers 2024年第5期15卷 222-238页

作者： Shailesh kumar Yadav AL.Ramanathan Chidambaram Sabarathinam alok kumar Manoj kumar Anshula Dhiman School of Environmental Sciences Jawaharlal Nehru UniversityNew Delhi 110067India Water Research Center Kuwait Institute for Scientific ResearchKuwait Department of Environmental Studies University of Delhi110007India Department of Earth and Environmental Sciences Indian Institute of Science Education and Research MohaliSector 81140306India

The hydro-geochemistry and isotopic variations in groundwater,coupled with sediment geochemistry,were investigated in the Middle Gangetic Plain,India,to better understand the aquifer dynamics that influence the arsenic(As)evolution and ***-four groundwater samples,thirteen River water samples,and two sediment cores(33 mbgl)were *** samples were analyzed for major ions and trace metals,including As and stable isotopic variability(δ^(2)H,δ^(18)O,andδ^(13)C).The study area was categorized into older and younger alluvium based on existing geomorphological *** alluvium exhibits higher As enrichment in sediment and groundwater,ranging of 2.59–31.52 mg/kg and bdl to 0.62 mg/*** samples were thermodynamically more stable with As(OH)_(3)species ranging from 88.5%to 91.4%and FeOOH from 69%to 81%,*** and mineralogical analysis suggested goethite and siderite act as a source and sink for ***,statistical analysis suggested reductive dissolution as the primary mechanism for As mobilization in the study ***-temporal analysis revealed elevated concentrations of As in the central and northeastern regions of the study *** isotope(δ^(2)H andδ^(18)O)analysis inferred active recharge conditions primarily driven by *** depleted d-excess value and enrichedδ^(18)O in the groundwater of younger alluvium indicate the effect of groundwater recharge with significant evaporation *** recharge potentially decreased the quantity of arsenic in groundwater,whereas evaporation enrichment increased *** infiltration during recharge introduces oxygenated water into the aquifer,leading to changes in the redox conditions and facilitating biogeochemical *** carbon isotope(δ^(13)C)results suggest that high microbial activity in younger alluvium promotes As leaching from sediment into the groundwater.

关键词： Groundwater recharge Reductive dissolution Older alluvium Younger alluvium Ghazipur Stable isotope

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Sources and dynamics of sedimentary organic matter in Sundarban mangrove estuary from Indo-Gangetic delta

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Ecological Processes 2017年第1期6卷 69-83页

作者： M.Bala Krishna Prasad alok kumar A.L.Ramanathan Dilip kumar Datta 22616 Shining Harness Street ClarksburgMD 20871USA School of Environmental Sciences Jawaharlal Nehru UniversityNew Delhi 110067India Environmental Science Discipline Khulna UniversityKhulna 9208Bangladesh

Introduction:Mangrove forests are highly productive ecosystems distributed along the tropical coast *** biogeochemistry of mangroves are primarly driven by both allochthonous and autochthonous *** of organic matter in coastal ecosystems enables to understand the biogeochemical transformation of organic matter and its influence on ecosystem productivity in response to various changing environmental ***,the elemental and stable carbon and nitrogen levels were employed to understand the organic matter(OM)dynamics in the Sundarban mangrove ecosystem(India-Bangladesh).Results:Differences in stable isotope values indicate that variable sources influence the OM dynamics in Sundarban *** progressive enrichment inδ13C levels along the land-coastal continuum indicates that the terrestrial and marine inputs are dominant at the landward and seaward ends,*** CuO oxidationderived lignin phenol monomers describe significant levels of total lignin are preserved in Sundarban mangrove sediments during *** phenol monomer ratios are lower than the plant litter explaining that aromatic ring cleavage is the dominant mechanism for the lignin ***,the Ad/Al ratios were higher than the plant litter explaining the oxidation of propyl side chain of vascular OM influencing the carbon cycling in Sundarban ***,the Ad/Al ratios describe the vascular OM degradation is through the oxidation of propyl side ***:The regional variability in land-use regulates the spatial variability in C,N,OC/TN ratio,δ13C andδ15N between the Indian and the Bangladesh Sundarban mangroves and indicates that in the upstream terrestrial organic matter and/or mangrove plant litter contribute significant amount of organic matter,whereas the marine POC influences the organic matter dynamics in *** three end-member mixing model applying terrestrial plant litter,seston,and marine POC as e

关键词： Sundarban mangrove Organic carbon Stable isotopes Lignin phenols Three end-member mixing model

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Two-warehouse inventory model for deteriorating items with demand influenced by innovation criterion in growing technology market

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Journal of Management Analytics 2018年第3期5卷 198-212页

作者： alok kumar Udayan Chandab FORE School Of Management B-18Qutub Institutional AreaNew DelhiIndia Department of Management BITS PilaniRajasthanIndia

One of the major concerns for the technology market is the demand volatility andits impact on inventory policies. Demand volatility in the technology sector mayarise due to many factors namely customer choices, competition, growingmarket size, and so on. Often companies use rented warehouses to absorb anyfluctuations in demand. Unfortunately, warehouse and inventory researchesignore the phenomenon of growing market size to formulate policy decisions. Inthis paper, we proposed a two-warehouse inventory model with deterioration fortechnology products with linearly increasing market size where demand followsinnovation diffusion criterion. The model is based on the assumption that theholding costs in the rented warehouse are more than the own warehouse. Asimple solution procedure also discussed to solve nonlinear cost *** example and sensitivity analysis are also used to describe the utilityof the model.

关键词： two-warehouse inventory technology products deterioration innovation diffusion growing market size

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Spatial variability of soil hydraulic and physical properties in erosive sloping agricultural fields

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Water Science and Engineering 2023年第1期16卷 57-66页

作者： Deepak Singh alok kumar Mishra Sridhar Patra Sankar Mariappan Nisha Singh Saswat kumar Kar ICAR-Indian Institute of Soil and Water Conservation Dehradun 248195India Sam Higginbottom University of Agriculture Technology and SciencesPrayagraj 211007India Hemvati Nandan Bahuguna Garhwal University Srinagar(Garhwal)246174India

It is essential to minimize soil quality degradation in sloping agricultural fields through stabilization and improvement of soil hydraulic properties using sustainable soil *** study aimed to analyze the impact of different tillage practices,including conventional tillage(CT),minimum tillage(MT),and zero tillage(ZT),on soil hydraulic conductivity in a sloping agricultural field under maizeewheat *** results showed that the highest runoff volume(257.40 m3),runoff coefficient(42.84%),and soil loss(11.3 t)were observed when the CT treatment was *** contrast,the lowest runoff volume(67.95 m3),runoff coefficient(11.35%),and soil loss(1.05 t)were observed when the ZT treatment was *** soil organic carbon and aggregate mean weight diameter were found to be significantly greater(with mean values of 0.79%and 1.19 mm,respectively)with the ZT treatment than with the CT *** the tilled treatments(CT and MT),substantial changes in the saturated soil hydraulic conductivity(ks),near-saturated soil hydraulic conductivity(k),and water-conducting porosity(ε)were observed between two crop *** three soil parameters were significantly higher in the period after maize harvesting than in the wheat growing *** contrast,no significant difference in these soil parameters was found when the untilled treatment(ZT)was carried *** regard to the slope positions,ks,k,andεshowed different behaviors under different *** toe slope position showed significantly lower ks andεvalues than the summit and middle slope *** the evaluated tillage practices,ZT was found to be the most promising means to improve the soil hydro-physical properties and effectively reduce surface runoff and soil erosion.

关键词： Hydraulic conductivity Macropore Conservation tillage Spatiotemporal variability Soil erosion

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On the development of cat swarm metaheuristic using distributed learning strategies and the applications

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International Journal of Intelligent Computing and Cybernetics 2019年第2期12卷 224-244页

作者： Usha Manasi Mohapatra Babita Majhi alok kumar Jagadev Department of Computer Science and Information Technology Institute of Technical Education and ResearchSiksha‘O’Anusandhan Deemed to be UniversityBhubaneswarIndia Department of Computer Science and Information Technology G.G.VishwavidyalayaCentral UniversityKoni BilaspurIndia School of Computer Engineering KIIT Deemed to be UniversityBhubaneswarIndia

Purpose–The purpose of this paper is to propose distributed learning-based three different metaheuristic algorithms for the identification of nonlinear *** proposed algorithms are experimented in this study to address problems for which input data are available at different geographic *** addition,the models are tested for nonlinear systems with different noise *** a nutshell,the suggested model aims to handle voluminous data with low communication overhead compared to traditional centralized processing ***/methodology/approach–Population-based evolutionary algorithms such as genetic algorithm(GA),particle swarm optimization(PSO)and cat swarm optimization(CSO)are implemented in a distributed form to address the system identification problem having distributed input *** of different distributed approaches mentioned in the literature,the study has considered incremental and diffusion ***–Performances of the proposed distributed learning-based algorithms are compared for different noise *** experimental results indicate that CSO performs better compared to GA and PSO at all noise strengths with respect to accuracy and error convergence rate,but incremental CSO is slightly superior to diffusion ***/value–This paper employs evolutionary algorithms using distributed learning strategies and applies these algorithms for the identification of unknown *** few existing studies have been reported in which these distributed learning strategies are experimented for the parameter estimation task.

关键词： System identification Wireless sensor network Diffusion learning strategy,Distributed learning-based cat swarm optimization Incremental learning strategy

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Near-saturated soil hydraulic conductivity and pore characteristics as influenced by conventional and conservation tillage practices in North-West Himalayan region,India

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International Soil and Water Conservation Research 2021年第2期9卷 249-259页

作者： Deepak Singh alok kumar Mishra Sridhar Patra Sankar Mariappan Nisha Singh ICAR-Indian Institute of Soil and Water Conservation Dehradun248195UttarakhandIndia Sam Higginbottom University of Agriculture Technology and SciencesPrayagraj211007U.PIndia Hemvati Nandan Bahuguna Garhwal University(A Central University) Srinagar(Garhwal)246174UttarakhandIndia

Tillage plays an important role in modifying soil hydraulic *** objective of the present study was to evaluate the effect of conservation tillage practices in a maize-wheat cropping system on nearsaturated soil hydraulic properties and pore characteristics in the North-West Himalayan region,*** treatments *** tillage(CT),minimum tillage(MT),and zero tillage(ZT)were evaluated in terms of field saturated hydraulic conductivity(ks),unsaturated hydraulic conductivity k(h),the inverse of capillary length(a),flow-weighted mean pore radius(r0),numbers of pores per square meter(n0)and water-conducting macroporosity(Ɛ).The above hydraulic conductivity and pore characteristics were derived from steady-state water flux(q)measured using hood infiltrometer at 0,1,and3 cm pressure head for each treatment after seven years of establishment of this tillage *** revealed significantly(p0.50 mm conducted about 63.60,68.01,and 75.97%of total flow(at 0 cm pressure head)in the corresponding water-conducting macroporosity of 0.00030,0.00044,and 0.00069%of soil volume under CT,MT,and ZT,***,zero-tillage based agriculture system was found to improve near-saturated soil hydraulic properties.

关键词： Near-saturated hydraulic conductivity Macropores Tillage Flow weighted mean pore radius Water-conducting macroporosity

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Machining of circular micro holes by electrochemical micro-machining process

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Advances in Manufacturing 2013年第4期1卷 314-319页

作者： alok kumar Das P. Saha alokkumarDas·ParthaSaha Indian School of Mines Dhanbad Jharkhand India Indian Institute of Technology Kharagpur KharagpurWest Bengal India

Machining of micro holes with micro electro- chemical machining （micro ECM） process has been carried out with an indigenously developed set up. This paper describes relevant problems and solutions for the circular micro holes machining process on 304 stainless steel sheets with 60 μm thickness using high speed steel cylindrical tool of diameter 500 ~tm and using dilute I-I2SO4 as elec- trolyte. The taper angle variation of the machined hole is analyzed and reported for different experimental setting parameters. The minimum value of the taper angle of machined holes is achieved at the parameter setting of 0.4 mol/L H2504, 700 kHz, 600 ns and 21 V, for stainless steel sheets and HSS tool.

关键词： Micro machining - Micro ECMMicro-hole ~ Electrochemical dissolution ~Short pulse voltage ~ Pulse power supply

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Phytochemicals with ROS scavenging activity and nutritional analyses of an underutilized fruit from Odisha(Eugenia roxburghii DC.)

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Food Bioscience 2022年第5期49卷 915-923页

作者： alok kumar Giri Bhagyashree Biswal Biswajit Jena Laxmikanta Acharya Molecular Biology and Genetic Engineering Lab Centre for BiotechnologySchool of Pharmaceutical SciencesSiksha‘O’Anusandhan(Deemed to be University)BhubaneswarOdishaIndia

Eugenia roxburghii is a wild edible species belonging to the Myrtaceae *** bears delicious edible nutritious *** species holds both pharmacological and nutritional ***,they are still underutilized due to a lack of information on food *** research aims to evaluate the phytochemical and nutritional components of *** with the objective to study the influence of the constituents on ROS scavenging activity and its comparison among other Eugenia *** revealed that the fruits contained a discrete level of phytochemicals such as polyphenols(1.74 mg g􀀀^(-1))and flavonoids(2.11 mg g^(-1)).*** extract showed significant scavenging activity having an IC50 value of 6.13μg/*** to proximate analysis,the fruit has a substantial amount of calories(125.6 kcal/100 g),carbs(31.41%),protein(5.4%),dietary fibers(1.28 g/100 g),an acceptable amount of moisture(79.52%)for preservation,a reasonable amount of sugar(5.18%),and a very low amount of ash(0.72%)and fat as compared to other Eugenia ***,*** was found to be rich in Vitamin C(81.5 mg/100 g)while having a very low salt level but discovered to be high in potassium(89.12 mg/100 g)and Calcium(34.41 mg/100 g).Based on the findings of this study,the *** plant might be explored and used as a nutraceutical and food supplement in the pharmaceutical *** results of this research enable consumers to locate more affordable sources for a variety of supplements and advantages to prevent micronutrient deficiencies.

关键词： Eugenia roxburghii Phytochemicals Nutritional value Antioxidant activity DPPH

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Frameworks of Non-Orthogonal Multiple Access Techniques in Cognitive Radio Communication Systems

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China Communications 2019年第6期16卷 129-149页

作者： Prabhat Thakur alok kumar S Pandit G Singh S N Satashia Department of Electronics and Communication Engineering Jaypee University of Information TechnologyWaknaghat-173215India Department of Electrical and Electronics Engineering Auckland Park Kingsway Campus University of JohannesburgPO Box 524Johannesburg-2006S Africa Space Application Centre Indian Space Research OrganizationAhmedabad-380015India

Recently,the increasing demand of radio spectrum for the next generation communication systems due to the explosive growth of applications appetite for bandwidths has led to the problem of spectrum *** potential approaches among the proposed solutions to resolve this issue are well explored cognitive radio(CR)technology and recently introduced non-orthogonal multiple access(NOMA)*** the techniques are employed for efficient spectrum utilization and assure the significant improvement in the spectral ***,the significant improvement in spectral efficiency can be achieved by combining both the *** the CR is well-explored technique as compared to that of the NOMA in the field of communication,therefore it is worth and wise to implement this technique over the *** this article,we have presented the frameworks of NOMA implementation over CR as well as the feasibility of proposed ***,the differences between proposed CR-NOMA and conventional CR frameworks are ***,the potential issues regarding the implementation of CR-NOMA are explored.

关键词： cognitive radio channel state information non-orthogonal multiple access power division multiple access superposition-coding successive-interference-cancellation

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Re-estimation and comparisons of alternative accounting based bankruptcy prediction models for Indian companies

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Financial Innovation 2016年第1期2卷 59-86页

作者： Bhanu Pratap Singh alok kumar Mishra School of Economics University of HyderabadProf.C.R.Rao RoadGachibowliHyderabad-500046 TelanganaIndia

Background:The suitability and performance of the bankruptcy prediction models is an empirical *** aim of this paper is to develop a bankruptcy prediction model for Indian manufacturing companies on a sample of 208 companies consisting of an equal number of defaulted and non-defaulted *** of 208 companies,130 are used for estimation sample,and 78 are holdout for model *** study reestimates the accounting based models such as Altman EI(Journal of Finance 23:19189-209,1968)Z-Score,Ohlson JA(Journal of Accounting Research 18:109-131,1980)Y-Score and Zmijewski ME(Journal of Accounting Research 22:59-82,1984)X-Score *** paper compares original and re-estimated models to explore the sensitivity of these models towards the change in time periods and financial ***:Multiple Discriminant Analysis(MDA)and Probit techniques are employed in the estimation of Z-Score and X-Score models,whereas Logit technique is employed in the estimation of Y-Score and the newly proposed *** performance of all the original,re-estimated and new proposed models are assessed by predictive accuracy,significance of parameters,long-range accuracy,secondary sample and Receiver Operating Characteristic(ROC)***:The major findings of the study reveal that the overall predictive accuracy of all the three models improves on estimation and holdout sample when the coefficients are *** the contesting models,the new bankruptcy prediction model outperforms other ***:The industry specific model should be developed with the new combinations of financial ratios to predict bankruptcy of the firms in a particular *** study further suggests the coefficients of the models are sensitive to time periods and financial ***,researchers should be cautioned while choosing the models for bankruptcy prediction to recalculate the models by looking at the recent data in order to get higher predictive accuracy.

关键词： Bankruptcy prediction Indian manufacturing companies MDA Logit Probit Unstable coefficient Predictive accuracy Receiver operating characteristic Long range accuracy

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