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Advances in Materials Physics and Chemistry 2019年第1期9卷 1-10页

作者： N.Shara Sowmya Pravin Varade Narayanan Venkataramani ajit r.kulkarni Department of Metallurgical Engineering and Materials Science Indian Institute of Technology BombayMumbaiIndia

In this work, lead-free Na0.4Bi0.5 TiO3-K0.1Bi0.5TiO3 (NKBT) piezoelectric ceramics were prepared by the solid-state reaction method and their structural, ferroelectric and dielectric properties were systematically studied. NKBT sintered at 1150℃ for 4 h exhibited highly dense (96% - 98% of the theoretical density) and uniform grains of size 1.1 μm. The coexistence of tetragonal (P4bm) and rhombohedral (r3c) phases due to the presence of morphotrophic phase boundary for the chosen composition has been confirmed by the rietveld refinement studies. Enhanced ferroelectric properties such as remnant polarization (Pr) and coercive field (EC) are found to be 37 μC/cm2 and 30 kV/cm, respectively. The optimized synthesis procedure for NKBT ceramics resulted in enhanced strain (%) and converse piezoelectric coefficient (d33*) of 0.3 % and 554 pm/V which is attributed to smaller grain size and switching of non 180o domains. NKBT ceramics with such excellent piezoelectric properties can be considered as a promising candidate for actuator applications.

关键词： Lead-Free Piezoelectric Morphotropic Phase Boundary Converse Piezoelectric Coefficient Actuator

Geochemical and petrological studies of high sulfur coal and overburden from Makum coalfield (Northeast India) towards understanding and mitigation of acid mine drainage

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International Journal of Coal Science & Technology 2024年第1期11卷 133-147页

作者： Angana Mahanta Debashis Sarmah Nilotpol Bhuyan Monikankana Saikia Sarat Phukan K.S.V.Subramanyam ajit Singh Prasenjit Saikia Binoy K.Saikia Coal and Energy Division CSIR-North East Institute of Science and TechnologyJorhatAssam785006India Academy of Scientific&Innovative research(AcSIr) Ghaziabad201002India Department of Geological Sciences Gauhati UniversityGuwahatiAssam781014India Geochemistry Division CSIR-National Geophysical Research InstituteUppal RoadHyderabad500007India

Opencast coal mining produces trash of soil and rock containing various minerals,that are usually dumped nearby the abandoned sites which causes severe environmental concern including the production of acid mine drainage(AMD)through oxidation pyrite *** current study entailed assessing the potential production of AMD from an opencast coal mining region in Northeast part of *** order to have a comprehensive overview of the AMD problem in Makum coalfield,the physico-chemical,geochemical,and petrological characteristics of the coal and overburden(OB)samples collected from the Makum coalfield(Northeast India)were thoroughly *** maceral compositions reveal that coal features all three groups of macerals(liptinite,vitrinite,and inertinite),with a high concentration of liptinite indicating the coal of perhydrous,thereby rendering it more ***(FeS_(2))oxidation kinetics were studied by conducting the aqueous leaching experiments of coal and(OB)samples to interpret the chemical weathering under controlled laboratory conditions of various temperature and time periods,and to replicate the actual mine site *** coupled plasma-optical emission spectroscopy(ICP-OES)was operated to detect the disposal of some precarious elements from coal and OB samples to the leachates during our controlled leaching *** rare earth element(rEE)enrichment in the samples shows the anthropogenic incorporation of the rEE in the coal and *** experiments reveal the change in conductivity,acid producing tendency,total dissolved solid(TDS),total Iron(Fe)and dissolved Sulfate(SO_(4)^(2−))ions on progress of the leaching ***,the discharge of FeS_(2) via atmospheric oxidation in laboratory condition undergoes a significant growth with the rise of temperature of the reaction systems in the environment and follows pseudo first order kinetics.A bio-remediative strategies is also reported in this paper to mitigate AMD water by

关键词： Opencast mining Pyrite oxidation Coal geochemistry Coal petrology rare earth elements AMD remediation

Cardiovascular risk factors among older persons with cognitive frailty in middle income country

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World Journal of Clinical Cases 2024年第17期12卷 3076-3085页

作者： Azianah Mohamad Ibrahim Devinder Kaur ajit Singh Arimi Fitri Mat Ludin Noor Ibrahim Mohamed Sakian Nurul Fatin Malek rivan Suzana Shahar Centre for Healthy Ageing and Wellness Faculty of Health SciencesUniversiti Kebangsaan MalaysiaWilayah Persekutuan Kuala Lumpur 50300Malaysia Basic Medical Sciences University of CyberjayaSelangor Darul EhsanMalaysia 63000Malaysia

BACKGrOUND Cognitive frailty,characterized by the coexistence of cognitive impairment and physical frailty,represents a multifaceted challenge in the aging *** role of cardiovascular risk factors in this complex interplay is not yet fully *** To investigate the relationships between cardiovascular risk factors and older persons with cognitive frailty by pooling data from two cohorts of studies in *** A comprehensive approach was employed,with a total of 512 communitydwelling older persons aged 60 years and above,involving two cohorts of older persons from previous *** related to cardiovascular risks,namely sociodemographic factors,and cardiovascular risk factors,including hypertension,diabetes,hypercholesterolemia,anthropometric characteristics and biochemical profiles,were pooled for *** frailty was defined based on the Clinical Dementia rating scale and Fried frailty *** risk was determined using Framingham risk *** analyses were conducted using SPSS version *** Of the study participants,46.3%exhibited cognitive *** risk factors including hypertension(Or:1.60;95%CI:1.12-2.30),low fat-free mass(Or:0.96;95%CI:0.94-0.98),high percentage body fat(Or:1.04;95%CI:1.02-1.06),high waist circumference(Or:1.02;95%CI:1.01-1.04),high fasting blood glucose(Or:1.64;95%CI:1.11-2.43),high Framingham risk score(Or:1.65;95%CI:1.17-2.31),together with sociodemographic factors,i.e.,being single(Or 3.38;95%CI:2.26-5.05)and low household income(Or 2.18;95%CI:1.44-3.30)were found to be associated with cognitive *** Cardiovascular-risk specific risk factors and sociodemographic factors were associated with risk of cognitive frailty,a prodromal stage of *** identification and management of cardiovascular risk factors,particularly among specific group of the population might mitigate the risk of cognitive frailty,hence preventing dementia.

关键词： Cognitive frailty Older persons Cardiovascular risk factors Frailty Mild cognitive impairment

An active rUNX1-ID1/ID3 axis governs differentiation and chemoresistance of cancer stem cell population in epithelial ovarian cancer cells

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BIOCELL 2022年第1期46卷 75-86页

作者： ajit CDHADVE PrITHA rAY Imaging Cell Signaling&Therapeutics Laboratory Advanced Centre for TreatmentResearch and Education in CancerTata Memorial CentreNavi Mumbai410210India Homi Bhabha National Institute Mumbai400094India

Progression,relapse,and therapy resistance are the most challenging features of cancer therapy that have been postulated to be driven by Cancer Stem Cell(CSC)*** enigmatic subpopulation of cancer cells has therefore emerged as promising therapeutic *** earlier reported enrichment of CSC-like side population(SP)with increasing resistance towards Cisplatin and Paclitaxel either alone or in combination in epithelial ovarian cancer(EOC)*** SP population is a small proportion of the total population of cancer cells characterised with high expression of drug transporters,a unique feature of stem cells and thereby can be isolated through their efflux properties of DNA binding *** the bulk non-SP(NSP)population of the cancer cells lack overexpression of the drug transporters and thus can be identified as the dye containing *** this study,we show that increased expression of runt related transcription factor 1(rUNX1)maintains undifferentiated state of CSC-like SP cells through upregulation of inhibitors of DNA binding/differentiation genes(ID1 and ID3)in late cisplatinpaclitaxel resistant *** rUNX1 expression was found to correlate with decreased median overall survival and disease-free survival in The Cancer Genome Atlas(TCGA)data set of high grade serous ovarian cancer(HGSOC)*** protein-protein interaction network analysis of 397 upregulated genes in rUNX1-high samples of TCGA data show significant enrichment of pathways known to negatively regulate CSC *** rUNX1 inhibition not only induces CSC differentiation but also downregulates anti-apoptotic protein BCL2 in both SP and NSP cells and potentiates cytotoxic effects of Cisplatin-Paclitaxel in chemoresistant EOC *** of BCL2 through Venetoclax treatment,a small molecule BH3 mimic,sensitized these cells to platinum taxol ***,our data reveal new regulatory roles by rUNX1 to modulate CSC differentiation via ID

关键词： Cancer stem cells Differentiation rUNX1 ID1 ID2 BCL2 Chemoresistance Ovarian cancer

Mitigation on self-discharge behaviors via morphological control of hierarchical Ni-sulfides/Ni-oxides electrodes for long-life-supercapacitors

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Journal of Materials Science & Technology 2022年第18期113卷 217-228页

作者： Dhananjay Mishra Niraj Kumar ajit Kumar SeungGi Seo SungHun Jin Department of Electronic Engineering Incheon National UniversityIncheon 406-772 and also with Convergence Research Center for Insect VectorsIncheon National UniversityRepublic of Korea

To cope up with the sustainable energy storage goals for supercapacitors(SCs),the self-discharge in SC electrodes is a significant hurdle,and thereby,nickel sulfide(NS)with high conductivity is adopted as a test vehicle for understanding the morphological evolution effects for long-life ***,honeycomb-like NS is hierarchically formed over hydrothermally grown nickel oxide(NO)via successive ionic layer adsorption reaction(SILAr)*** heterostructure shows a fivefold improvement in specific capacitance from 348 F g^(−1) to 2077 F g^(−1)at 1 mV s^(−1) over bare ***,the remarkable upliftment of capacitance retention is achieved from 60.7%to 92.3%even after 3000 cycles via morphological control of NS/NO hetero-structure with the help of highly conductive *** importantly,the self-discharge behaviors and synergistic role of leakage current associated with morphological evolution via NS overcoating are studied in *** particular,the self-discharge mitigation from 45%(NO)to 35%(NS20/NO)due to the NS/NO heterostructure and the behind mechanism are ascribed to the activated-controlled Faradaic reaction coupled with a charge *** study emphasizes the potential importance of composite heterostructure by tuning the electrical conductivity and morphological adjustment NO via consecutive overcoating of NS through SILAr as a novel *** enhances charge storage,redox kinetics,and the mitigation of self-discharge properties of the active electrode *** practical validation on sustainable energy storage,NS20/NO supercapacitors illuminate the LED for 35%longer than NO after one-time charging,potentially beneficial for the next generation SCs.

关键词： Morphological evolution Self-discharge SILAr overcoating Supercapacitors Heterostructure

Nitrate removal from groundwater using chemically modified coconut husk based granular activated carbon:characterization of the adsorbent,kinetics and mechanism

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Systems Microbiology and Biomanufacturing 2023年第2期3卷 370-383页

作者： Solomon K.M.Huno Jewel Das Eric Dvan Hullebusch ajit P.Annachhatre Eldon r.rene Pollution Prevention and resource recovery Chair Group Department of Water SupplySanitation and Environmental EngineeringIHE Delft Institute of Water EducationP.O.Box 30152601 DA DelftThe Netherlands Environmental Engineering and Management Department of EnvironmentEnergy and Climate ChangeSchool of EnvironmentResource and DevelopmentAsian Institute of Technology58 Moo 9Km.42Paholyothin HighwayP.O.Box 4Klong Luang 12120Pathum ThaniThailand National University of Ireland Galway University RoadGalway H91 TK33Ireland Bangladesh Council of Scientific and Industrial research(BCSIr) BCSIR Laboratories ChattogramChattogram 4220Bangladesh Universite Paris Cite Institut de Physique du Globe de ParisCNRSF‑75005 ParisFrance School of Engineering Indian Institute of Technology MandiA4‑209MandiHimachal Pradesh 175001India

In this study,a highly porous chemically activated granular activated carbon(GAC)was prepared from coconut husk and tested as an adsorbent to remove nitrate from contaminated *** prepared GAC was characterized by Fouriertransform infrared spectroscopy(FTIr),thermogravimetric and differential thermal analysis(TGA/DTA),scanning electron microscopy(SEM)and the Brunauer-Emmett-Teller(BET)surface area(SBET)*** effects of various process parameters such as initial nitrate concentration,contact time and adsorbent dose on nitrate removal efficiency(response)by the modified GAC were investigated using the statistically significant response surface methodology and Box-Behnken design of *** experimental data were fitted to well-known adsorption isotherms and kinetic models to ascertain the mechanism of the adsorption *** of variance(ANOVA)was performed to determine the significance of the individual and the interactive effects of process variables on the *** BET surface area(SBET)and micropore volume of the prepared GAC from coconut husk was 1120 m^(2)/g and 0.392 cm^(3)/g,*** experimental results showed that physisorption was the main adsorption mechanism governing the process,while the rate of adsorption was limited at initial nitrate concentrations>10 mg/*** Langmuir mono-layer adsorption isotherm best fitted the experimental data with a maximum adsorption capacity of 6.0±1.3 mg/g(~92.5%)with an adsorbent dose of 0.1 g/50 mL,an equilibrium time of 6 h at 28±2℃,and at pH 7.6(±0.2).Among the tested process variables,the adsorbent dose and initial nitrate concentration showed significant effects on the nitrate removal efficiency.

关键词： Nitrate adsorption Groundwater Granular activated carbon response surface methodology(rSM) Box-Behnken Coconut Husk

Corrosion Study of Base Material and Welds of a Ni-Cr-Mo-W Alloy

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Acta Metallurgica Sinica(English Letters) 2017年第4期30卷 326-332页

作者： ajit Mishra Haynes International Inc. 1020 West Park AvenueKokomo IN 46904 USA

Alloys containing chromium （Cr） and molybdenum （Mo）, as the major alloying elements, are widely used in various industries where the material experiences corrosive environments. Chromium （Cr）, when added in an optimum amount, forms a Cr203 passive film which protects the underlying metal in aggressive solutions. Molybdenum （Mo） forms its oxides in the low pH solutions, thus, enhances the uniform corrosion resistance of an alloy in reducing acids and assists in inhibition to localized corrosion. Minor alloying elements, like tungsten （W） and copper （Cu）, also improve the overall corrosion resistance of an alloy in specific solutions. In the present study, corrosion resistance behavior of commercial iron- based alloys （316L SS, 254 SMO and 20Cb3） and nickel-based alloys （Mone1400, Alloy 625 and C-276） was studied in the acidic solutions. While the corrosion behavior of wrought alloys has been widely studied, there is little to no information on the corrosion performance of their welds, typically being the weak regions for corrosion initiation and propagation. Therefore, an attempt was undertaken to investigate the uniform and localized corrosion performance of base metal, simulated heat-affected zone and all-weld-metal samples of a Ni-Cr-Mo-W alloy, C-276. The study was conducted in aggressive acidic solutions. Various corrosion and surface analytical techniques were utilized to analyze the results.

关键词： Iron-chromium-molybdenum Nickel-chromium-molybdenum-tungsten All-weld-metal Heat-affected-zone Acids Acidified ferric chloride Potentiodynamic Scanning electronmicroscopy (SEM)

Performance of Corrosion-resistant Alloys in Concentrated Acids

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Acta Metallurgica Sinica(English Letters) 2017年第4期30卷 306-318页

作者： ajit Mishra research and Technology Haynes International 1020 ParkAve Kokomo IN 46902 USA

Nickel alloys containing optimum amounts of chromium （Cr）, molybdenum （Mo） and tungsten （W） are widely used in the chemical processing industries due to their tolerance to both oxidizing and reducing conditions. Unlike stainless steel （SS）, Ni-Cr-Mo （W） alloys exhibit remarkably high uniform corrosion resistance in major concentrated acids, like hydrochloric acid （HC1） and sulfuric acid （H2SO4）. A higher uniform corrosion resistance of Ni-Cr-Mo （W） alloys, compared to other alloys, in concentrated acids can be attributed to the formation of protective oxide film of Mo and W in reducing acids, and Cr oxide film in oxidizing solutions. The localized corrosion resistance of Ni-Cr-Mo （W） alloys, containing high amount Cr as well as Mo （or Mo ＋ W）, is also significantly higher than that of other commercially available alloys. The present study investigates the role of alloying elements, in nickel alloys, to uniform corrosion resistance in concentrated acids （HC1, HC1 ＋ oxidizing impurities and H2SO4） and localized corrosion performance in chloride-rich environments using ASTM G-48 test methodology. The corrosion tests were conducted on various alloys, and the results were analyzed using weight loss technique and electrochemical techniques, in conjunction with surface char- acterization tools.

关键词： Nickel-chromium-molybdenum-tungsten Corrosion-resistant alloys reducing acid Oxidants Localized corrosion Surface characterization

Charge transfer of carbon nanomaterials for efficient metal‐free electrocatalysis

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Interdisciplinary Materials 2022年第1期1卷 28-50页

作者： rajib Paul Qingfeng Zhai ajit K.roy Liming Dai Department of Macromolecular Science and Engineering Case School of EngineeringCase Western Reserve UniversityClevelandOhioUSA Australian Carbon Materials Centre(A-CMC) School of Chemical EngineeringUniversity of New South WalesSydneyNew South WalesAustralia Materials and Manufacturing Directorate Air Force Research LaboratoryDaytonOhioUSA

recently,carbon-based metal-free electrocatalysts(C‐MFECs)have drawn considerable research attention because of their attractive physicochemical characteristics,cost-effectiveness,and ability to convert and store energy *** intramolecular charge transfer among different parts of the carbon electrocatalyst and/or intermolecular charge transfer between elec-trocatalyst and electrolyte dictate the ultimate energy conversion *** results and theoretical analyses have demonstrated that rational design of metal-free carbon nanomaterials,coupled with proper in-tramolecular charge transfer through heteroatom doping,incorporation of Stone-Wales defects,and/or intermolecular charge transfer through adsorp-tion of appropriate molecules/moieties,can promote efficient *** this article,we will first provide the related theoretical principles and then present an overview on the rational design and development of C-MFECs for efficient charge transfer,followed by elucidating charge-transfer processes for different electrocatalytic reactions related to renewable energy conversion and environmental remediation ***,the current challenges and future perspectives in this exciting field will be discussed.

关键词： carbon catalyst charge transfer defect doping

Effect of ultrasonic assisted sintering on mechanical properties and degradation behaviour of Mg15Nb3Zn1Ca biomaterial

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Journal of Magnesium and Alloys 2021年第6期9卷 1989-2008页

作者： ajit Kumar Pulak M Pandey Department of Mechanical Engineering Indian Institute of TechnologyDelhiNew Delhi 110016India

The present work investigates the effect of ultrasonic power(%)and the time of ultrasonic vibration on the sintered density and ultimate compressive strength(UCS)of Mg15Nb3Zn1Ca fabricated using ultrasonic assisted conventional sintering(UACS).The customized UACS setup was designed and manufactured to conduct the experimentations.A customized ultrasonic stepped horn assembly was used for providing vibrations to the sample during ***,to evaluate the efficacy of ultrasonic vibration parameters,the developed setup was used to sinter Mg15Nb3Zn1Ca composite *** study unveiled an increased sintered density and UCS of the fabricated sample by the increase in ultrasonic power(%).Moreover,a decrease in sintered density and UCS was observed with an increase in the time of ultrasonic vibration beyond a certain *** sintered with the assistance of ultrasonic vibration at 100%ultrasonic power,and 20 min of ultrasonic vibration resulted in a sintered density of 1.928±0.062 g·cm^(-3)and UCS of 234.9±12.3 *** obtained mechanical properties of the fabricated sample were comparable to the properties of cortical *** surface morphology and elemental compositions of samples fabricated using UACS declared a fair dispersion of reinforcement in the matrix containing merely the source *** results of corrosion test have showed that the assistance of ultrasonic vibration suppressed the degradation behaviour of the sintered sample after performing electrochemical study of samples using 3-electorde cell ***15Nb3Zn1Ca fabricated using UACS showed a 50.18%and 9.08%of reduction in corrosion rate over conventionally sintered pure Mg and Mg15Nb3Zn1Ca *** addition,electrochemical impedance spectroscopy(EIS)results indicated an enhanced corrosion resistance of the Mg15Nb3Zn1Ca composite material when fabricated at 100%of ultrasonic power with 20 min of vibration *** from that,electrochemical equivalent circuits also result

关键词： Ultrasonic assisted sintering Magnesium Corrosion EIS Mechanical properties