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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

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Synthesis of Co3O4 Nanoparticles Wrapped Within Full Carbon Matrix as an Anode Material for Lithium Ion Batteries

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Acta Metallurgica Sinica(English Letters) 2018年第2期31卷 164-170页

作者： Subhalaxmi Mohapatra Shantikumar V.Nair alok Kumar Rai Amrita Centre for Nanosciences and Molecular Medicine Amrita Vishwa Vidyapeetham Amrita University Kochi Kerala 682041 India

A facile polyol-assisted pyro-synthesis method was used to synthesize Co3O4 nanoparticles embedded into carbon matrix without using any conventional carbon source. The surface analysis by scanning electron microscopy showed that the Co3O4 nanoparticles（-20 ± 5 nm） are tightly enwrapped within the carbon matrix. CHN analysis determined the carbon content was only 0.11% in the final annealed sample. The Co3O4@carbon exhibited high capacities and excellent cycling performance as an anode at various current rates（such as 914.4 and 515.5 mAh g^-1 at 0.25 and1.0 C, respectively, after 50 cycles; 318.2 mAh g^-1 at a high current rate of 5.0 C after 25 cycles）. This superior electrochemical performance of the electrode can be attributed to the various aspects, such as,（1） the existence of carbon matrix, which acts as a flexible buffer to accommodate the volume changes during Li^＋ion insertion/deinsertion and facilitates the fast Li^＋and electron transfer and（2） the anchoring of Co3O4 nanoparticles within the carbon matrix prevents particles agglomeration.

关键词： Co3O4 Carbon matrix Pyro-synthesis Anode Lithium ion battery

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Colorectal cancer screening in African Americans:practice patterns in the United *** we doing enough?

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Gastroenterology Report 2016年第2期4卷 136-140,I0002页

作者： Abhijeet Waghray alok Jaina Nisheet Waghray Department of Medicine MetroHealth Medical Center/Case Western Reserve UniversityClevelandOHUSA Division of Gastroenterology and Hepatology MetroHealth Medical Center/Case Western Reserve UniversityClevelandOHUSA

Background:Colorectal cancer(CRC)is a common form of malignancy and a leading cause of death in the United *** decreases CRC incidence and *** Americans are at an increased risk of developing CRC,and recommendations are to initiate screening at the age of *** study aims to assess the rate of screening for colorectal cancer in African Americans between the ages of 45–***:African Americans between the ages of 45–49 were identified in the Explorys national *** who completed a colonoscopy,sigmoidoscopy or fecal occult blood test were identified and stratified by sex and insurance status.A P value<0.05 was considered ***:A total of 181200 African Americans were identified as eligible for *** 31480 patients(17.4%)received at least one screening procedure for *** majority of patients(66.7%)were screened via *** American females were more likely to complete a screening test(17.8%vs 16.7%;P<0.01).The majority of patients(66.0%)who completed a screening test had private ***:Race,gender and barriers to medical care contribute to disparities in CRC screening *** African Americans,CRC screening remains *** public health initiatives,medical record alerts and improved communication between providers and patients are fundamental to addressing issues that impact poor adherence to CRC screening in African Americans.

关键词： colorectal cancer screening race

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A general-purpose machine learning framework for predicting properties of inorganic materials

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npj Computational Materials 2016年第1期2卷 70-76页

作者： Logan Ward Ankit Agrawal alok Choudhary Christopher Wolverton Department of Materials Science and Engineering Northwestern UniversityEvanstonILUSA Department of Electrical Engineering and Computer Science Northwestern UniversityEvanstonILUSA

A very active area of materials research is to devise methods that use machine learning to automatically extract predictive models from existing materials *** prior examples have demonstrated successful models for some applications,many more applications exist where machine learning can make a strong *** enable faster development of machine-learning-based models for such applications,we have created a framework capable of being applied to a broad range of materials *** method works by using a chemically diverse list of attributes,which we demonstrate are suitable for describing a wide variety of properties,and a novel method for partitioning the data set into groups of similar materials to boost the predictive *** this manuscript,we demonstrate how this new method can be used to predict diverse properties of crystalline and amorphous materials,such as band gap energy and glass-forming ability.

关键词： method properties inorganic

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Development of lead-free multifunctional materials Bi(Co_(0.45Ti0.45Fe0.10)O3

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Progress in Natural Science:Materials International 2018年第3期28卷 308-314页

作者： Nitin Kumar alok Shukla R.N.P.Choudhary Department of Physics National Institute of Technology Mizoram Department of Physics Siksha ‘O′Anusandhan University

A lead free multiferroic material,Bi(Co0.45Ti0.45Fe0.10)O3（BCTF45/10）was synthesized by a solid-state reaction route at high ***45/10 powder was prepared using appropriate raw maretials in oxide powders with methanol ***-prepared circular shaped pellets were sintered at 1053 K for 6 h to produce a compact *** structural properties and elemental analysis were determined using X-ray diffraction and energy-dispersive X-ray spectroscopy techniques respectively at room *** microstructure or surface morphology of the sintered sample was carried out by using field emission scanning electron microscope（FE-SEM）.The XRD analysis shows that the compound exhibits the single-phase of orthorhombic *** average crystallite size estimated using the Scherrer's technique was found to be 30 *** influence of Co and Ti substitution（at Bi and Ti sites of Bi Fe O3）on some physical and electrical properties of Bi Fe O3was examined by using phase sensitive multimeter in a wide frequency and temperature *** magnetic nature of the sample was studied using vibrating sample *** of room temperature magnetic hysteresis loop exhibits the enhanced ferromagnetic characteristic with saturation magnetization of 5.091 emu/g and coercive field of 0.213 k Oe *** enhanced magnetic properties highlight various potential applications of Co/Ti doped BCTF45/10 materials.

关键词： Multifunctional material Dielectric constant and loss Electrical characteristics Impedance spectroscopy

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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

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Chemically modified silica gel with 1-{4-[(2-hydroxy-benzylidene)amino]phenyl}ethanone:Synthesis, characterization and application as an efficient and reusable solid phase extractant for selective removal of Zn(Ⅱ) from mycorrhizal treated fly-ash samples

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Journal of Environmental Sciences 2013年第6期25卷 1252-1261页

作者： R.K.Sharma Aditi Puri Anil Kumar alok Adholeya 2 Green Chemistry Network Centre Department of ChemistryUniversity of Delhi Biotechnology and Management of Bioresources Division The Energy and Resource Institute

1-{4-[（2-hydroxy-benzylidene）amino]phenyl}ethanone functionalized silica gel was synthesized and used as a highly efficient, selective and reusable solid phase extractant for separation and preconcentration of trace amount of Zn（II） from environmental matrices. The adsorbent was characterized by fourier transform infrared spectroscopy （FT-IR）, elemental analysis,~3C CPMAS NMR spectroscopy, scanning electron microscopy （SEM）, thermogravimetric analysis （TGA） and BET surface area analysis. The dependence of zinc extraction on various analytical parameters such as pH, type and amount of eluent, sample flow rate and interfering ions were investigated in detail. The material exhibited superior adsorption efficiency for Zn（II） with high metal loading capacity of 1.0 mmol/g under optimum conditions. After adsorption, the recovery （〉 98%） of metal ions was accomplished using 1.0 mol/L HNO3 as an eluent. The sorbent was also regenerated by microwave treatment in milder acidic environment （0.1 mol/L HNO3）. The lower detection limit and preconcentration factor of the present method were found out to be 0.04 ~tg/L and 312.5 respectively. The modified silica surface possessed excellent selectivity for the target analytes and the adsorption/desorption process remained effective for at least ten consecutive cycles. The optimized procedure was successfully implemented for the extraction of Zn（II） from mycorrhizal treated fly ash and pharmaceutical samples with reproducible results.

关键词： solid phase extraction silica gel preconcentration fly-ash zinc

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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

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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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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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