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Boulder-induced form roughness and skin shear stresses in a gravel-bed stream

Journal of Mountain Science 2024年第1期21卷 346-360页

作者： DAS Ratul datta Akash Civil Engineering Department National Institute of Technology AgartalaAgartala-799046India

Boulder spacing in mountain rivers and near-wake flow zones within the boulder array is very useful for fish habitat and growth of aquatic organisms.The present study aims to investigate how the boulder array and spacing influence the near-bed flow structures in a gravel-bed stream.Boulders are staggered over a gravel-bed stream with three different inter-boulder spacing namely(a)large(b)medium and(c)small spacing.An acoustic Doppler velocimeter was used for flow measurements in a rectangular channel and the results were compared with those acquired from numerical simulation.The time-averaged velocity profiles at the near-wake flow zones of boulders experience maximum flow retardation which is an outcome of the boulder-induced form roughness.The ratio of velocity differences associated to form and skin roughness and its positive magnitude reveals the dominance of form roughness closest to the boulders.Form roughness computed is 1.75 to 2 times higher than the skin roughness at the near-wake flow region.In particular,the collective immobile boulders placed at different inter-boulder spacings developed high and low bed shear stresses closest to the boulders.The low bed shear stresses characterised by a secondary peak developed at the trough location of the boulders is attributed to the skin shear stress.Further,the spatial averaging of time-averaged flow quantities gives additional impetus to present an improved illustration of fluid shear stresses.The formation of form-induced shear stress is estimated to be 17%to 23%of doubleaveraged Reynolds shear stress and partially compensates for the damping of time-averaged Reynolds shear stress in the interfacial sub-layer.The quadrant analysis of spatial velocity fluctuations depicts that the form-induced shear stresses are dominant in the interfacial sub-layer and have no significance above the gravel-bed surface.

关键词： Array of boulders Near wake flow zones Velocity distributions Skin roughness Form induced shear stresses

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Application of Bootstrap in Dose Apportionment of Nuclear Plants Via Uncertainty Modeling of the Effluent Released from Plants

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World Journal of Nuclear Science and Technology 2012年第1期2卷 41-47页

作者： debabrata datta 不详

Nuclear power plants are always operated under the guidelines stipulated by the regulatory body. These guidelines basically contain the technical specifications of the specific power plant and provide the knowledge of the discharge limit of the radioactive effluent into the environment through atmospheric and aquatic route. However, operational constraints sometimes may violate the technical specification due to which there may be a failure to satisfy the stipulated dose apportioned to that plant. In a site having multi facilities sum total of the dose apportioned to all the facilities should be constrained to 1 mSv/year to the members of the public. Dose apportionment scheme basically stipulates the limit of the gaseous and liquid effluent released into the environment. Existing methodology of dose apportionment is subjective in nature that may result the discharge limit of the effluent in atmospheric and aquatic route in an adhoc manner. Appropriate scientific basis for dose apportionment is always preferable rather than judicial basis from the point of harmonization of establishing the dose apportionment. This paper presents an attempt of establishing the discharge limit of the gaseous and liquid effluent first on the basis of the existing value of the release of the same. Existing release data for a few years (for example 10 years) for any nuclear power station have taken into consideration. Bootstrap, a resampling technique, has been adopted on the existing release data sets to generate the corresponding population distribution of the effluent release. Cumulative distribution of the population distribution obtained is constructed and using this cumulative distribution, 95th percentile (upper bound) of the discharge limit of the radioactive effluents is computed. Dose apportioned for a facility is evaluated using this estimated upper bound of the release limit. Paper de- scribes the detail of the bootstrap method in evaluating the release limit and also presents the comparative study of the dose apportionment

关键词： Dose Apportionment Radioactive Effluent Cumulative Distribution Bootstrap Percentile

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Therapeutic potential and pharmacological mechanism of visnagin

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Journal of Integrative Medicine 2024年第4期22卷 399-412页

作者： Poonam Yadav Sumeet Kumar Singh Sayantap datta Saloni Verma Aarti Verma Arnab Rakshit Anjana Bali Jasvinder Singh Bhatti Amit Khurana Umashanker Navik Department of Pharmacology School of Health SciencesCentral University of Punjab Department of Pharmacological and Pharmaceutical Sciences College of PharmacyUniversity of Houston Department of Human Genetics and Molecular Medicine School of Health SciencesCentral University of Punjab

Visnagin is a furanochromone and one of the most important compound in the Ammi visnaga (L.) Lam (a synonym of Visnaga daucoides Gaertn.) plant,which is used to cure various ailments.Many investigations into the bioactive properties of visnagin have been studied to date.The literature on visnagin demonstrates its biological properties,including anti-inflammatory,anti-diabetic,and beneficial effects in cardiovascular and renal diseases.Moreover,visnagin improves sperm quality parameters,stimulates steroidogenesis,and increases serum gonadotropins and testosterone levels,while decreasing proinflammatory cytokines,oxidative damage,genomic instability,and it modulates apoptosis.Thus,visnagin has emerged as an exciting lead for further research,owing to its potential in various unmet clinical needs.The current review summarized its basic structure,pharmacokinetics,and pharmacological effects,focusing on its mechanisms of action.The review will help to understand the potential of visnagin as an alternative treatment strategy for several diseases and provide insight into research topics that need further exploration for visnagin’s safe clinical use.

关键词： Ammi visnaga L. Anti-inflammatory Cancer Phytochemical Visnaga daucoides Gaertn Visnagin

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Hybrid Offset Slider Crank Mechanism for Anthropomorphic Flexion in Prosthetic Hands

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Journal of Bionic Engineering 2023年第1期20卷 308-322页

作者： Banibrata datta Sekar Anup Chander Srikanth Vasamsetti CSIR-CSIO Sector-30CChandigarh160030India

The underactuated fingers used in prosthetic hands account for a large part of design consideration in anthropomorphic prosthetic hand design.There are considerable numbers of designs available for underactuated prosthetic fingers in literature but,emulating the anthropomorphic flexion movement is still a challenge due to the complex nature of the motion.To address this challenge,a hybrid mechanism using both linkage-based mechanism and tendon-driven actuation has been proposed in this paper.The presented mechanism includes a novel offset slider-crank-based finger that has been designed using a combination of different lengths of cranks and connecting rods.The prototypes of both the new mechanism and the conventional tendon-driven mechanism are constructed and compared experimentally based on interphalangeal joint angle trajectory during flexion.The angles achieved through the new hybrid mechanism are compared with the conventional tendon-driven mechanism and the Root Mean Square Error(RMSE)values have been calculated by comparing to the anthropomorphic flexion angles of the published literature.The RMSE values calculated for three interphalangeal joints of the hybrid mechanism are found to be less than their counter-parts of the conventional tendon-driven mechanism.In addition to achieving resemblance to anthropomorphic flexion angles,the mechanism is designed within the anthropometric human finger dimensions.

关键词： Anthropomorphism Hybrid mechanism Prosthetic-Slider-crank.Underactuated

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Analyzing environmental flow supply in the semi-arid area through integrating drought analysis and optimal operation of reservoir

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Journal of Arid Land 2023年第12期15卷 1439-1454页

作者： Mahdi SEDIGHKIA Bithin datta College of Science and Engineering James Cook UniversityTownsville 4811Australia

This study proposes a novel form of environmental reservoir operation through integrating environmental flow supply,drought analysis,and evolutionary optimization.This study demonstrates that simultaneous supply of downstream environmental flow of reservoir as well as water demand is challenging in the semi-arid area especially in dry years.In this study,water supply and environmental flow supply were 40%and 30%in the droughts,respectively.Moreover,mean errors of supplying water demand as well as environmental flow in dry years were 6 and 9 m3/s,respectively.Hence,these results highlight that ecological stresses of the downstream aquatic habitats as well as water supply loss are considerably escalated in dry years,which implies even using environmental optimal operation is not able to protect downstream aquatic habitats properly in the severe droughts.Moreover,available storage in reservoir will be remarkably reduced(averagely more than 30×106 m3 compared with optimal storage equal to 70×106 m3),which implies strategic storage of reservoir might be threatened.Among used evolutionary algorithms,particle swarm optimization(PSO)was selected as the best algorithm for solving the novel proposed objective function.The significance of this study is to propose a novel objective function to optimize reservoir operation in which environmental flow supply is directly addressed and integrated with drought analysis.This novel form of optimization system can overcome uncertainties of the conventional objective function due to considering environmental flow in the objective function as well as drought analysis in the context of reservoir operation especially applicable in semi-arid areas.The results indicate that using either other water resources for water supply or reducing water demand is the only solution for managing downstream ecological impacts of the river ecosystem.In other words,the results highlighted that replanning of water resources in the study area is necessary.Replacing the conventional optimization system for

关键词： optimization reservoir operation droughts metaheuristic algorithms environmental flow regime

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The roles of MXenes in developing advanced lithium metal anodes

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Journal of Energy Chemistry 2022年第6期31卷 132-149,I0005页

作者： Nicolas Lucero Dayannara Vilcarino Dibakar datta Meng-Qiang Zhao Department of Chemical and Materials Engineering Newark College of EngineeringNew Jersey Institute of TechnologyNewarkNJ 07103USA Jose Marti Stem Academy Union CityNJ 07087USA Department of Mechanical and Industrial Engineering Newark College of EngineeringNew Jersey Institute of TechnologyNewarkNJ 07103USA

Lithium(Li) metal has emerged as the most promising anode for rechargeable Li batteries owing to its high theoretical specific capacities, low negative electrochemical potential, and superior electrical conductivity. Replacing the conventional graphite anodes with Li metal anodes(LMAs) provides great potential to exceed the theoretical limitations of current commercial Li-ion batteries, leading to nextgeneration high-energy–density rechargeable Li metal batteries(LMBs). However, further development of LMAs is hindered by several inherent issues, such as dangerous dendrite growth, infinite volume change, low Coulombic efficiency, and interfacial side reactions. MXenes, a family of two-dimensional(2 D) transition metal carbides and/or nitrides, have recently attracted much attention to address these issues due to their 2D structure, lithiophilic surface terminations, excellent electrical and ionic conductivity, and superior mechanical properties. Herein, an overview of recent advances in the roles of MXenes for stabilizing LMAs is presented. In particular, strategies of utilizing MXenes as the Li hosts, artificial protection layers, electrolyte additives, and for separator modifications to develop stable and dendrite-free LMAs are discussed. Moreover, a perspective on the current challenges and potential outlooks on MXenes for advanced LMAs is provided.

关键词： MXenes 2D materials Lithium dendrites Lithium metal anodes Stability

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Vitamin C and E supplementation and high intensity interval training induced changes in lipid profile and haematological variables of young males

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Sports Medicine and Health Science 2023年第2期5卷 137-145页

作者： Surojit Sarkar Swapan Kr Dey Gouriprosad datta Amit Bandyopadhyay Department of Physiology Rammohan College1021Raja Ram Mohan SaraniBaithakkhanaKolkata700009West BengalIndia Department of Sports Science University of CalcuttaUniversity Colleges of Science and Technology92A.P.C.RoadKolkata700009West BengalIndia Sports and Exercise Physiology Laboratory Department of PhysiologyUniversity of CalcuttaUniversity Colleges of Science and Technology92A.P.C.RoadKolkata700009West BengalIndia

High intensity interval training(HIIT)causes oxidative stress and haematological alteration.Present study was aimed to evaluate the effect of 8 weeks’supplementation of vitamin C and E on HIIT induced changes in lipid profile parameters and haematological variables.Hundred six male adolescent players were randomly assigned into five age-matched groups,i.e.,Control(no exercise+placebo),HIIT(placebo),HIIT+vitamin-C(1000mg/day),HIIT+vitamin-E 400 IU/day)and combined HIIT+vitamin C and E.Morning and evening sessions(90min)of HIIT included 4 phases(15min each)with 3 sets(4min each).Each 4min HIIT set consisted of 2min intense sprint workout(90%–95%of heart rate maximum[HRmax])followed by 1min active recovery(60%–70%HRmax)followed by 1min of complete rest(1:1 work-rest ratio).Lipid profile parameters,haematological variables,endurance capacity and vertical jump were evaluated by standard protocols.Significant decrease in body weight,fat%,total cholesterol,triglyceride,Total Cholesterol/High Density Lipoprotein-Cholesterol and significant increase in High Density Lipoprotein-Cholesterol,maximal oxygen consumption,vertical jump were observed for all four intervention groups.White blood cell count,red blood cell count,haemoglobin percentage and haematocrit values were significantly decreased while platelet count and platelet-to-leukocyte ratio(PLR)ratio were increased significantly only for HIIT group.Blood level of tocopherol and ascorbic acid was significantly increased(values were within the normal range)in all the respective vitamin supplemented groups.Supplementation of vitamin C and E secures health protection with suppressed haemolysis and improved inflammatory blood variables with enhanced explosive leg strength and lipid profile parameters without any concomitant change in endurance capacity.

关键词： Sprint interval training Lipid profile Haematological indices Haemolysis Athletes

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Nipah Virus Unveiled: A Review Article

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Advances in Bioscience and Biotechnology 2024年第3期15卷 161-173页

作者： Munama Magdum Md. Abir Tazim Chowdhury Mahmuda Khandaker Razdip datta Md. Naheed Rayhan Md. Siffat Uddin Md. Junayed Imam Bhuiyan Md. Ahaduzzaman Md. Abdullah Al-Mahammud Kabir Mohammad Zishan Uddin Md. Estiak Ullah Sahid Subrata Saha Department of Community Medicine Shaheed Monsur Ali Medical College Dhaka Bangladesh Department of Cardiothoracic and Vascular Surgery Evercare Hospital Dhaka Bangladesh Department of Microbiology Shaheed Monsur Ali Medical College Dhaka Bangladesh Department of Anesthesia Dhaka Dental College & Hospital Dhaka Bangladesh Department of Cardiothoracic Anesthesia Evercare Hospital Dhaka Bangladesh Department of Medicine Times Multicare Hospital Ltd. Dhaka Bangladesh Barking Havering and Redbridge University Hospitals NHS Trust Romford UK

Nipah virus (NiV) is a highly infectious zoonotic pathogen that poses a significant threat to human and animal health. First identified in Malaysia in 1998, NiV has since caused several outbreaks in Southeast Asia, with sporadic cases reported in Bangladesh and India. The virus is primarily transmitted to humans through direct contact with infected animals, primarily fruit bats, or through the consumption of contaminated fruits and their juices. NiV infection presents a wide spectrum of clinical features, ranging from mild respiratory illness to severe encephalitis, with a high case fatality rate. The incubation period typically ranges from 4 to 14 days, during which patients develop fever, headache, myalgia, and respiratory symptoms such as cough and sore throat. As the disease progresses, neurological signs become prominent, including altered consciousness, seizures, and focal deficits. Severe cases may exhibit acute respiratory distress syndrome and multi organ failure. Laboratory findings often include lymphocytopenia, thrombocytopenia, and elevated liver enzymes. Diagnosis of NiV infection requires specialized laboratory testing, including reverse transcription-polymerase chain reaction (RT-PCR) and serological assays. Currently, no specific antiviral treatment exists for NiV infection, and management primarily focuses on supportive care. Prevention and control strategies encompass public health interventions, surveillance, and raising awareness among healthcare providers and the general population. The emergence and re-emergence of NiV highlight the urgent need for continued research, improved diagnostic capabilities, and the development of effective vaccines and therapeutics to mitigate the impact of this deadly virus.

关键词： Nipah Virus Zoonotic Pathogen Outbreaks Surveillance

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Nanoengineering of Curved Supramolecular Polymers:Toward Single-Chain Mesoscale Materials

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Accounts of Materials Research 2022年第2期3卷 259-271页

作者： Sougata datta Sho Takahashi Shiki Yagai Department of Applied Chemistry and Biotechnology Graduate School of EngineeringChiba UniversityChiba 263-8522Japan Division of Advanced Science and Engineering Graduate School of Engineering and Institute for Global Prominent Research(IGPR)Chiba UniversityChiba 263-8522Japan

CONSPECTUS:Recently,supramolecular polymers(SPs),which depend on the formation of reversible bonds between monomers,have attracted attention as a class of materials that can overcome the potential environmental problems of conventional polymeric materials.The development of various supramolecular polymers is important not only for their direct application as materials but also because their unique polymerization processes and dynamic properties have a profound influence on the development of polymeric and small-molecule-based functional materials.In other words,by limiting the dimensionality of molecular assemblies to one dimension,we can discover the essential aspects of selfassembly and self-organization.In particular,supramolecular polymerization,in whichπ-electron-rich planar molecules are stacked one-dimensionally via multiple interactions,is interesting because it gives“π-stacked SPs”with one-dimensional crystal-like order.The excellent intrinsic(internal)structural order ofπ-stacked SPs is difficult to observe in higher-order structures that exhibit only a monotonous linear structure.However,our research has shown that when internal structural order intrinsically generates curvature,the curvature appears as a major feature of the entire polymer chain.This intrinsic curvature allows the formation of diverse topologies such as toroids,random coils,waves,spirals,and helicoids usingπ-stacked SPs and also allows structural changes at the single-polymer-chain level along a topology-dependent energy landscape.In other words,π-stacked SP-based nanomaterials could enable free control of the structure at the single-polymer-chain level.This Account will focus on our research into curved supramolecular polymers(CSPs)during the last five years.CSPs are formed by the hydrogen bonding between barbituratecontainingπ-conjugated molecules to produce giant supramolecular monomers.We first give an overview of the molecular design of the monomers required for the formation of CSPs,the unique energy landscape of CSPs,and their

关键词： materials curvature bonds

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Spatially explicit estimation of soil organic carbon stock of an estuarine mangrove wetland of eastern India using elemental analysis and very-fine resolution satellite data

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Ecological Processes 2022年第1期11卷 411-426页

作者： Debajit datta Madhumita Bairagi Mansa Dey Argha Pratim Pal Jibananda Gayen Department of Geography Jadavpur UniversityKolkata 700032India Department of Geography Sree Chaitanya CollegeHabra 743268India

Background:This study estimated the total soil organic C(SOC)stock of the wetland influence zone of Bichitrapur mangroves in eastern India in a spatially explicit manner.Both spatial and vertical distribution of SOC densities with respect to land use/land cover(LULC)pattern were assessed.Subsequently,some site-specific management strate-gies were forwarded towards enhancement of C sequestration potential.Methods:The changing patterns of LULC within the wetland influence zone of the site were analyzed using Landsat TM(30 m)and Pleiades-1A(2 m)imageries from 1988 to 2018.Point-specific SOC measurement was done using samples taken from four core-depth intervals(viz.D1:0–20 cm,D2:20–40 cm,D3:40–70 cm,D4:70–100 cm)at 89 locations belonging to different LULC categories.Spatial interpolation was applied on this point-based data to produce SOC density and stock models as a whole and at all core-depths.Relationships between SOC density,core-depth and present LULC were evaluated through multivariate statistical analyses.Results:The LULC transformations during last three decades suggested the gradual growth of mangrove plantations as well as agricultural and aquacultural activities.Most amount of SOC was concentrated in D1(37.17%)followed by D3(26.51%),while D4 had the lowest(10.87%).The highest mean SOC density was observed in the dense mangrove patches(248.92 Mg ha^(−1))and the lowest mean was in the Casuarina plantations(2.78 Mg ha^(−1)).Here,Spline method emerged as the best-fit interpolation technique to model SOC data(R^(2)=0.74)and estimated total SOC stock of the entire wetland influence zone as 169,569.40 Mg and the grand mean as 125.56 Mg ha^(−1).Overall,LULC was inferred as a major determinant of SOC dynamics with a statistically significant effect(p<0.001),whereas no such inference could be drawn for soil core-depth.Conclusions:The C sequestration potential of sites such as the present one could be increased with appropriate zone-wise plantation strategies,restriction on the land conversion to aquaculture and pr

关键词： Blue C density Core-depth Coastal wetland Dry combustion Land use conversion Wetland influence zone

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