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Evaluating mechanism and inconsistencies in hydraulic conductivity of unsaturated soil using newly proposed biochar conductivity factor

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Biochar 2023年第1期5卷 585-602页

作者： Ankit Garg Hong-Hu Zhu ajit k.sarmah Guoxiong Mei Vinay kumar Gadi Department of Civil and Environmental Engineering Shantou UniversityShantouChina Southwest University of Science and Technology MianyangSichuanChina School of Earth Sciences and Engineering Nanjing UniversityNanjingChina Department of Civil and Environmental Engineering University of AucklandAuckland 1142New Zealand Ocean College Zhejiang UniversityHangzhouChina School of Engineering Cardiff UniversityCardiff CF243AAUK

In the past few decades,numerous studies have been conducted to promote the use of biochar as a soil amendment and most recently,for compacted geo-engineered *** general,the definite trends of biochar effects on water retention and fertility of soils have been ***,the biochar effects on hydraulic conductivity,particularly unsaturated hydraulic conductivity of soil-biochar mix remain unclear,making it difficult to understand water seepage in both agricultural and geo-engineered infrastructures in semi-arid *** study examines the unsaturated hydraulic conductivity function derived based on the measurements of soil water characteristic curves of soil with biochar contents of 0%,5%and 10%.A new parameter“biochar conductivity factor(BCF)”is proposed to evaluate the inconsistency in reported biochar effects on soil hydraulic conductivity and to interpret it from various mechanisms(inter-and intra-pore space filling,cracking,aggregation,bio-film formation and piping/internal erosion).The impact of biochar content on unsaturated hydraulic conductivity appears to reduce as the soil becomes drier with minimal effect in residual *** comparison of near-saturated hydraulic conductivity with test results in the literature showed that the BCF is generally higher for smaller ratio of sand to fine content(clay and silt).Moreover,the particle size of biochar may have significant influence on soil *** scope of research has been highlighted with respect to biochar production for its applications in agriculture and geo-environmental *** term effects such as root decay and growth,aggregation and nutrient supply need to be considered.

关键词： Biochar conductivity factor(BCF) Unsaturated hydraulic conductivity Soil water characteristic curve(SWCC) Pyrolysis process

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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

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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)

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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

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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

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Variability in physical properties of plantation-grown progenies of Melia composita and determination of a kiln-drying schedule

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Journal of Forestry Research 2018年第5期29卷 1435-1442页

作者： Shailendra kumar Bhushan U.kelkar ajit k.Mishra Susanta k.Jena Forest Products Division Forest Research Institute

Plantation-grown progenies of Melia composita *** studied for variability in several physical properties： density,radial and tangential shrinkage,longitudinal permeability of heartwood and ***,flat-sawn planks from each of the progeny were subjected to a quick-drying test for determination of kilndrying *** mean density of the species was 0.39 g cm^（-3） and the wood may be categorized as light *** radial shrinkage（%） for the species was 2.8% with progeny-wise variation in radial shrinkage from 1.56 to 4.11%.Mean tangential shrinkage（%） for the species was 5.54% with progeny-wise variation in tangential shrinkage from 3.69 to 7.71%.The resultant tangentialradial shrinkage ratio was 1.98（less than two）,which suggests that the wood is relatively stable with respect to drying *** sapwood and heartwood longitudinal permeability of the species were 3.38 and 2.02 Darcy,*** longitudinal permeability of sapwood and heartwood indicate better drying and preservative properties of the *** quick-drying test method suggests that the species is less susceptible to drying *** the test,only moderate checks and cracks were observed.A tentative kiln-drying schedule was recommended based on these results.

关键词： Melia composita Willd. Density Radial and tangential shrinkage Longitudinal permeability Quickdrying test kiln-drying schedule

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Examining the policy-practice gap-The issue of crop burning induced Particulate Matter pollution in Northwest India

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Ecosystem Health and Sustainability 2020年第1期6卷 282-297,281页

作者： Leena ajit kaushal Economics Management Development Institute GurgaonGurugramIndia

The study examine the efficacy of government policy interventions initiated since 2014 to curb FCRB in NW Indian states and the related air pollution in Delhi-NCR during *** regression analysis suggests an increase in PM2.5 of~69μg/m3/1000 surge in *** retrieved data suggest an overall declining trend of~1606 and~4308 fire counts per year across NW states during October-November *** monthly PM2.5 concentrations in New Delhi exhibits a decline of~2.18μg/m3 and~5.17μg/m3 per year over the same *** an overall increase of~17.6%rice productivity,a noted decrease in fire activity over the period is an encouraging move,likely a result of some control imposed by authorities on *** to a significant~35.5%rise in wheat productivity,data records rising trend in wheat residue burning activities in April(~1298/year)and May(~2402/year)but do not trigger extreme pollution due to difference in intensity of fires across harvesting seasons and relatively weak northwesterly wind ***,the overall high PM2.5 levels in October-November and April-May compared to NAAQS 24-hour average of 60μg/m3,disproves the overall efficacy of government policies to curb FCRB and related air pollution in IGP region.

关键词： Field crop residue burning(FCRB) emissions particulate matter mitigation India government interventions

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DEM simulation of polydisperse systems of particles in a fluidized bed

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Particuology 2009年第1期7卷 9-18页

作者： Nobuyuki Tagami ajit Mujumdar Masayuki Horio Bio Applications and Systems Engineering Tokyo University of Agriculture & TechnologyNaka-choKoganei-shiTokyo 184-8588Japan

Numerical simulations based on three-dimensional discrete element model （DEM） are conducted for mono-disperse, binary and ternary systems of particles in a fluidized bed. Fluid drag force acting on each particle depending on its size and relative velocity is assigned. The drag coefficient corresponding to Ergun＇s correlation is applied to the system of fluidized bed with particle size ratios of 1：1 for the mono-disperse system, 1：1.2, 1：1.4 and 1：2 for the binary system and 1：1.33：2 for the ternary system by keeping total volume and surface area of the particles constant. Results indicated that a reasonable estimation of drag force based on individual particle diameters as compared to that of the mean diameter of the particles is achieved in the fluid cells. The total translational kinetic energy of the particles is found to increase as the particle size ratio increases, suggesting an enhanced momentum transfer in polydisperse particle systems. Systems with wide particle size distribution exhibited higher particle velocities around bubbles, resulting in faster bubble growth and its subsequent rise through the fluidized bed.

关键词： Discrete element method Fluid drag force Fluidized bed Particle size distribution

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Development of Mg based biomaterial with improved mechanical and degradation properties using powder metallurgy

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Journal of Magnesium and Alloys 2020年第3期8卷 883-898页

作者： ajit kumar Pulak M.Pandey Department of Mechanical Engineering Indian Institute of TechnologyDelhi110016India

In the present work,biocompatible materials such as niobium(Nb),zinc(Zn)and calcium(Ca)have been blended with magnesium(Mg)to develop a novel biomaterial(BM)with improved mechanical and corrosion resistant *** metallurgy(PM)technique was used to fabricate Mg based *** powder of all aforementioned materials were mixed homogenously in specific quantities to create a uniform composite *** order to analyse the influence of process parameters on the mechanical properties of the fabricated part,experiments were performed considering central composite design(CCD).The effect of powder metallurgical parameters namely percentage Nb,compaction pressure,heating rate,sintering temperature and soaking time on the ultimate compressive strength(UCS)and sintered density was studied in the present *** was found that the UCS and sintered density increased with increase in compaction pressure,heating rate and sintering *** results also revealed that the increase in soaking time and percentage Nb,increased sintered density and UCS to a certain *** increase in these two parameters,sintered density and UCS *** electron microscopy(SEM)images of the fabricated samples showed reduction in porosity with the increase in heating ***,X-ray diffraction(XRD)results revealed that no other phase or impurities were found during sintering of Mg based *** optimum process parameters were obtained to develop Mg based BM for maximum UCS and sintered ***,the Mg based BM samples fabricated at optimum process parameters were used for corrosion testing in simulated body fluid(SBF)solution at a temperature of 37±0.5℃.The Mg based BM yielded improved mechanical properties with reduced corrosion rates as compared to pure Mg.

关键词： Biomaterials Powder metallurgy Magnesium Corrosion Metal matrix composite

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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

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