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Sustainable ifngerling production technique of endangeredLabeo calbasu (Hamilton, 1822) based on different protein levels in ponds

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Journal of Coastal Life Medicine 2017年第2期5卷 51-58页

作者： Md.Abdus Samad Shamol Chandra Barman Sujit kumar Chatterjee Md.Mustafizur Rahman alok kumar paul Department of Fisheries University of RajshahiRajshahi-6205Bangladesh Fish Inspection and Quality Control Department of FisheriesDhakaBangladesh

Objective:To conduct on sustainable fingerling production technique of endangered Labeo calbasu (Hamilton, 1822) (L. calbasu) based on different protein levels in ponds. Methods: The experiment was carried out under rearing pond in fish hatchery complex with three treatments group each having three replicates under department of fisheries, University of Rajshahi.L. calbasu were stocked at 41990/ha in T1, T2 and T3, respectively. The initial length ofL. calbasu in three treatments were (4.60 ± 0.10) cm and initial weights were (3.48 ± 0.01) g. Fishes were fed with 28%, 30%, 32% protein supplement for T1, T2, T3, respectively. The fishes were initially fed at 10% of body weight on 1st and 2nd fortnight. Then it was decreased at 8% of body weight on 3rd and 4th fortnight. Finally in 5th fortnight they were fed 5% of body weight. The physico-chemical characteristics of pond water were measured fortnightly. Results: The mean final weight gain was found highest in T3 (40.87 ± 0.01) g which was significant compared to T1 and T2. SGR (% bwd–1) was found 2.83 ± 0.02 (T1), 3.04 ± 0.01 (T2) and 3.39 ± 0.01 (T3). The highest survival rate ofL. calbasu was found in T3 (90.00 ± 1.00) and the lowest was found in T1 (87.00 ± 1.00). The best FCR (1.54 ± 0.01) was observed in T3 fed with 32% protein supplement. The highest production was observed in T3 (1672.20 ± 16.96 kg/ha/75 days) and lowest was observed in T1(1055.50 ± 29.04 kg/ha/75 days). The highest net benefit was calculated in T3 (260663.00 ± 4326.88 tk.) and lowest was found in T1 (112831.00 ± 7383.66 tk.). The CBR was found 0.60 ± 0.04, 0.80 ± 0.02 and 1.16 ± 0.02 in T1, T2 and T3, respectively. There were significant differences in CBR values among the three treatments. Conclutions:In this study, growth parametersi.e., weight gain, SGR (% bwd–1), length gain, total yield were significantly (P < 0.05) improved in T3 treatment fed with 32% protein supplemented diets.

关键词： Fingerling Production Endangered Labeo calbasu Protein levels

Biphasic reduction model for predicting the impacts of dye-bath constituents on the reduction of tris-azo dye Direct Green-1 by zero valent iron(Fe^0)

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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

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 effectiveness of patch repaired carbon fiber laminate under quasi-static indentation loading

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Defence Technology（防务技术） 2024年第4期34卷 29-41页

作者： alok kumar Chinmaya kumar Sahoo A.Arockiarajan Department of Applied Mechanics Indian Institute of Technology MadrasChennai 600036India

Damage caused due to low-velocity impacts in composites leads to substantial deterioration in their residual strength and eventually provokes structural *** work presents an experimental investigation on the effects of different patch and parent laminate stacking sequences on the enhancement of impact strength of Carbon Fiber Reinforced Polymers(CFRP)composites by utilising the adhesively bonded external patch repair *** evolution study is also performed with the aid of Acoustic Emission(AE).Two different quasi-isotropic configurations were selected for the parent laminate,viz.,[45°/45°/0°/0°]s and[45°/0°/45°/0°]*** Static Indentation(QSI)test was performed on both the pristine laminates,and damage areas were detected by using the C-scan inspection *** laminates were repaired by using a single-sided patch of two different configurations,viz.,[45°/45°/45°/45°]and[45°/0°/0°/45°],and employing a circular plug to fill the damaged *** different combinations of repaired laminates with two configurations of each parent and patch laminate were produced,which were further subjected to the QSI *** results reveal the effectiveness of the repair method,as all the repaired laminates show higher impact resistance compared to the respective pristine *** of[45°/0°/0°/45°]configuration when repaired by taking[45°/45°/0°/0°]s and[45°/0°/45°/0°]s as parents exhibited 68%and 73%higher peak loads,respectively,than the respective pristine ***,parent and patch of configuration[45°/0°/45°/0°]s and[45°/0°/0°/45°],respectively,attain the highest peak load,whereas[45°/45°/0°/0°]s and[45°/45°/45°/45°]combinations possess the most gradual decrease in the load.

关键词： Carbon fiber reinforced polymers(CFRP) Quasi-isotropic laminate Quasi static indentation(QSI) Acoustic emission(AE) Composite repair

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

Slip flow of micropolar fluid through a permeable wedge due to the effects of chemical reaction and heat source/sink with Hall and ionslip currents:an analytic approach

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Propulsion and Power Research 2020年第3期9卷 289-303页

作者： Khilap Singh alok kumar Pandey Manoj kumar Department of Mathematics Statisticsand Computer ScienceG.B.Pant University of Agriculture and TechnologyPantnagar263145UttarakhandIndia Department of Mathematics Graphic Era Deemed to Be UniversityDehradun248002UttarakhandIndia

This study focuses on the combined impact of heat source/sink and chemical reaction on slip flow of micropolar fluid through a permeable wedge in the existence of Hall and ion-slip *** governing highly non-lincar PDEs were altered into a set of non-linear coupled ODEs by using similarity *** transformation method(DTM)has been implemented in transformed ODEs *** comparison with previous literatures was performed and the data of this study was found to be in accordance with each *** analytical solutions for skin-friction coefficients(surface drag forces),Nussclt and Sherwood numbers are depicted through graphs and *** study of boundary layer flow over a wedge surface plays an imperative role in the field of aerodynamics,heat exchanger,ground water pollution and geothermal system etc.

关键词： Chemical reaction Differential transformation method(DTM) Hall current and ion slip Heat source/sink Micropolar fluid Slip velocity

Numerical solution of micropolar fluid flow via stretchable surface with chemical reaction and melting heat transfer using Keller-Box method

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Propulsion and Power Research 2021年第2期10卷 194-207页

作者： Khilap Singh alok kumar Pandey Manoj kumar Department of Mathematics Statistics and Computer ScienceG.B.Pant University of Agriculture and TechnologyPantnagarUttarakhand263145India Department of Mathematics Graphic Era Deemed to be UniversityDehradunUttarakhand248002India

The main theme of this research is to find the numerical results of stagnation point flow of micropolar fluid over a porous stretchable surface due to the physical effects of internal heat generation/absorption,melting heat transfer and chemical reaction via Keller-Box method(KBM).The graphs and tables are depicted and explained for various embedded *** range of melting heat transfer parameter is 0≤M≤3,the range of chemical reaction parameter is 0≤K_(r)≤1 whereas the values of space-temperature dependent heat source/sink parameters lies in-0:4≤Q≤0:4 and-2≤Q*≤*** upshots of the current problem illustrate that at fluid-solid interface,rate of HMT(heat and mass transfer)declined on escalating the values of stretching ***,as the values of internal heat source/sink parameter increases,heat transfer rate declines at fluid-solid interface.

关键词： Chemical reaction Implicit finite difference Keller-Box method(KBM) Internal heat generation/absorption Heat and mass transfer(HMT) Melting heat transfer Porous medium

Modeling the effect of time delay in implementation of mitigation policies on the control of atmospheric greenhouse gases

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International Journal of Biomathematics 2023年第8期16卷 75-108页

作者： alok kumar Verma Maitri Verma Department of Mathematics School of Physical and Decision Science Babasaheb Bhimrao Ambedkar University Lucknow India

Mitigation of the enhanced greenhouse gas(GHG)concentrations in the Earth's atmosphere is imperative to meet the climate change mitigation *** of many countries are developing and implementing various mitigation strategies to reduce their GHG ***,a time delay between the formulation and implementation of these mitigation policies can affect their effectiveness in controlling greenhouse gas levels in the *** work presents a nonlinear mathematical model to investigate the effect of application of mitigation strategies and the delay involved in their implementation over the reduction of atmospheric greenhouse *** model formulation,it is assumed that the mitigation strategies work two-fold;first they reduce the GHG emission rate from the anthropogenic source and second they increase the removal rate of greenhouse gas from the atmosphere.A comprehensive stability analysis of the proposed model system is made to examine its long-term *** model analysis shows that an increase in the implementation rate of mitigation strategies and their efficiencies to cut down the GHG emission rate from point sources and increase the GHG uptake rate lead to reduction in equilibrium GHG *** is found that a long delay in the execution of mitigation policies can destabilize the system dynamics and leads to the generation of periodic *** expression for the threshold value of the delay parameter at which periodic oscillations arise via Hopf-bifurcation is *** stability and direction of bifurcating periodic solutions are discussed.A sensitivity analysis is performed to investigate the effect of changes in key parameters over system dynamics.

关键词： Mathematical model greenhouse gases global warming mitigation strategies time delay Hopf-bifurcation

Effect of Sintering Temperature and Heating Rate on Crystallite Size,Densification Behaviour and Mechanical Properties of Al-MWCNT Nanocomposite Consolidated via Spark Plasma Sintering

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Acta Metallurgica Sinica(English Letters) 2018年第10期31卷 1019-1030页

作者： Lavish kumar Singh alok Bhadauria Subhodeep Jana Tapas Laha Department of Metallurgical and Materials Engineering Indian Institute of Technology Kharagpur Kharagpur India Centre for Healthcare Science and Technology Indian Institute of Engineering Science and Technology Shibpur India

Powder mixture of ball-milled aluminium and functionalized multi-walled carbon nanotubes was compacted via spark plasma sintering （SPS） to study effects of sintering temperature and heating rate. An increase in sintering temperature led to an increase in crystallite size and density, whereas an increase in heating rate exerted the opposite effect. The crystallite size and relative density increased by 85.0% and 14.3%, respectively, upon increasing the sintering temperature from 400 to 600℃, whereas increasing the heating rate from 25 to 100 ℃/min led to respective reduction by 30.0% of crystallite size and 1.8% of relative density. The total punch displacement during SPS for the nanocomposite sintered at 600 ℃ （1.96 mm） was much higher than that of the sample sintered at 400 ℃ （1.02 mm） confirming positive impact of high sintering temperature on densification behaviour. The maximum improvement in mechanical properties was exhibited by the nanocomposite sintered at 600 ℃ at a heating rate of 50℃/min displaying microhardness of 81 4- 3.6 VHN and elastic modulus of 89 4- 5.3 GPa. The nanocomposites consolidated at 400 ℃ and 100 ℃/min, in spite of having relatively smaller crystallite size, exhibited poor mechanical properties indicating the detrimental effect of porosity on the mechanical properties.

关键词： Al nanocomposite Multi-walled carbon nanotubes Ball milling Spark plasma sintering Densification behaviour Mechanical properties