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Geochemistry of core sediments from the southeastern Bay of Bengal:Inferences on weathering and early diagenetic changes

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Geoscience Frontiers 2021年第2期12卷 495-504页

作者： A.Prajith abhishek Tyagi P.John Kurian National Centre for Polar and Ocean Research(NCPOR) Ministry of Earth Sciences(MoES)Headland SadaVasco-da-Gama403804GoaIndia

A sediment core(ABP24/05),collected at a water depth of 3520 m from the southeastern Bay of Bengal was studied to determine the change in chemical weathering during the last glacial to deglacial periods and the factors of sedimentary environment which controlled earliest diagenetic changes in the sediment after its *** ratios of K/Rb,Ti/Al and Zr/Rb during~45 to~18 cal kyr *** the core sediments may be attributed to the stronger physical erosion and turbidity currents activity during this *** might have brought a higher quantity of unaltered minerals to the study *** ratios of K/Rb,Zr/Rb,and Ti/Al and increase of SiO_(2)/TiO_(2),Rb/Al and Cs/Al from~18 cal kyr *** present may be indicating an increase in the rate of chemical weathering during this *** time of increased chemical weathering in the study area is consistent with deglaciation warming in the tropical Indian Ocean and strengthening of river runoff into the Andaman *** change during the interglacial period by increased solar insolation thereby strengthened the summer monsoon which might have led to intensified chemical weathering in the source region since~18 cal kyr *** low organic carbon(OC),high Mn/Al,Fe/Al and the Mn-oxides minerals precipitation indicate prevailing of oxic conditions during~11 cal kyr *** the core sediments,which is contradictory to suboxic conditions developed in the deep ocean sediments in the western Bay of Bengal and the equatorial Indian *** low terrigenous influx and export of less OC to the bottom sediments might have created a favorable condition for the formation of Mn-oxides in the study area during Holocene.

关键词： Bay of Bengal Trace elements Chemical weathering Summer monsoon Mn-oxides

Elastoplastic analysis of AA7075-O aluminum sheet by hybrid micro-scale representative volume element modeling with really-distributed particles and in-situ SEM experimental testing

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Journal of Materials Science & Technology 2022年第28期123卷 201-221页

作者： Qingping Sun Shahryar Asqardoust abhishek Sarmah Mukesh K.Jain College of Aerospace and Civil Engineering Harbin Engineering UniversityHarbin 150001China Department of Mechanical Engineering McMaster UniversityHamiltonON L8S4L7Canada

This paper addresses the challenge of reconstructing randomly distributed second-phase particlestrengthened microstructure of AA7075-O aluminum sheet material for computational *** particle characteristics in 3D space were obtained from focused ion beam and scanning electron microscopy(FIB-SEM)and SEM-based Electron Backscatter Diffraction/Energy Dispersive X-ray Spectrometry(EBSD/EDS)techniques.A theoretical framework for analysis of elastic-plastic deformation of such3D microstructures is ***-induced shear band formation,void initiation,growth and linkage at large plastic strains during uniaxial tensile loading were investigated based on reconstructed 3D representative volume element(RVE)models with real-distribution of particles and the results compared with experimental ***-situ SEM interrupted tension tests along transverse direction(TD)and rolling direction(RD),employing microscopic-digital image correlation(μ-DIC)technique,were carried out to investigate slip bands,micro-voids formation and obtain microstructural strain *** resulting local strain maps were analyzed in relation to the experimentally observed plastic flow localization,failure modes and local stress maps from simulations of RVE *** influences of particle size,shape,orientation,volume fraction as well as matrix-particle interface properties on local plastic deformation,global stress-strain/strain-hardening curves and interfacial failure mechanisms were studied based on 3D RVE *** possible,the model results were compared with in-situ tensile test *** general,good agreement was observed,indicating that the real 3D microstructure-based RVE models can accurately predict the plastic deformation and interfacial failure evolution in AA7075-O aluminum sheet.

关键词： Representative volume element AA7075-O aluminum sheet In-situ SEM Microscopic-digital image correlation(μ-DIC) Elastoplastic behavior

嗜铬细胞瘤和副神经节瘤的系统性放射性药物治疗

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中华核医学与分子影像杂志 2024年第3期44卷 187-192页

作者：席闯(译) 罗全勇(审校) 上海交通大学医学院附属第六人民医院上海200233

良性嗜铬细胞瘤和副神经节瘤通常可以通过手术切除治愈,但转移性疾病的治疗在疾病控制和症状控制方面都存在挑战。幸运的是,有几种治疗方式可用于转移性疾病的治疗,包括化疗、放射治疗和外科手术。放射性核素标记的间碘苄胍(MIBG)和生... 详细信息

良性嗜铬细胞瘤和副神经节瘤通常可以通过手术切除治愈,但转移性疾病的治疗在疾病控制和症状控制方面都存在挑战。幸运的是,有几种治疗方式可用于转移性疾病的治疗,包括化疗、放射治疗和外科手术。放射性核素标记的间碘苄胍(MIBG)和生长抑素受体显像为将这些放射性药物用作诊疗剂奠定了基础。^(131)I-MIBG治疗神经内分泌肿瘤历史悠久,美国食品与药品监督管理局最近批准将高比活度^(131)I-MIBG用于治疗转移性或不可手术的嗜铬细胞瘤或副神经节瘤,使^(131)I-MIBG的治疗应用更加广泛,并重新引起人们的兴趣。尽管已有文献报道使用90Y-或177Lu-1,4,7,10-四氮杂环十二烷-1,4,7,10-四乙酸(DOTA)偶联的生长抑素类似物对嗜铬细胞瘤和副神经节瘤进行多肽受体放射性核素治疗,但随着177Lu-DOTA-D-苯丙氨酸1-酪氨酸3-苏氨酸8-奥曲肽(DOTATATE)在美国和欧洲获批,以及美国国家综合癌症网络指南建议将其用于转移性或不可手术的嗜铬细胞瘤和副神经节瘤患者,这些药物引起了人们新的兴趣。已有证据表明这些放射性药物是对转移性或无法手术的嗜铬细胞瘤或副神经节瘤患者有效的姑息治疗方法。在该篇继续医学教育文章中,作者讨论了使用^(131)I-MIBG和90Y-或177Lu-DOTA生长抑素类似物治疗嗜铬细胞瘤和副神经节瘤。

关键词：嗜铬细胞瘤副神经节瘤生长抑素 MIBG DOATATE 多肽受体放射性核素治疗

Tectono-magmatic evolution of Tethyan oceanic lithosphere in supra subduction zone fore arc regime:Geochemical fingerprints from crust-mantle sections of Naga Hills Ophiolite

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Geoscience Frontiers 2021年第3期12卷 19-41页

作者： Anisha Verencar abhishek Saha Sohini Ganguly Manikyamba C. CSIR-National Institute of Oceanography Dona PaulaGoa 403004India School of Earth Ocean and Atmospheric SciencesGoa UniversityTaleigão PlateauGoa 403206India CSIR-National Geophysical Research Institute Uppal RoadHyderabad 500007India

The Naga Hills Ophiolite(NHO)belt in the Indo-Myanmar range(IMR)represents a segment of Tethyan oceanic crust and upper mantle that was involved in an eastward convergence and collision of the Indian Plate with the Burmese Plate during the Late ***,we present a detailed petrological and geochemical account for the mantle and crustal sections of NHO,northeastern India to address(i)the mantle processes and tectonic regimes involved in their genesis and(ii)their coherence in terms of the thermo-tectonic evolution of Tethyan oceanic crust and upper *** NHO suite comprises well preserved crustal and mantle sections discretely exposed at Moki,Ziphu,Molen,Washelo and Lacham *** ultramafic-mafic lithologies of NHO are mineralogically composed of variable proportions of olivine,orthopyroxene,clinopyroxene and *** primary igneous textures for the mantle peridotites have been overprinted by extensive serpentinisation whereas the crustal section rocks reflect crystal cumulation in a magma *** normalised REE profiles for the cumulate peridotite-olivine gabbro-gabbro assemblage constituting the crustal section of NHO show flat to depleted LREE patterns consistent with their generation from depleted MORB-type precursor melt in an extensional tectonic setting,while the mantle peridotites depict U-shaped REE patterns marked by relative enrichment of LREE and HREE over *** features collectively imply a dual role of depleted MORB-type and enriched arc-type mantle components for their genesis with imprints of melt-rock and fluid-rock ***,studied lithologies from NHO correspond to a boninitic to slab-proximal Island Arc Tholeiite affinity thereby conforming to an intraoceanic supra subduction zone(SSZ)fore-arc regime coherent with the subduction initiation *** geochemical attributes for the crustal and mantle sections of NHO as mirrored by Zr/Hf,Zr/Sm,Nb/Ta,Zr/Nb,Nb/U,Ba/Nb,Ba/Th,Ba/La and Nd/

关键词： Tethyan Ocean Naga Hills Ophiolite Suprasubduction Zone Subduction initiation Fore arc extension Mantle refertilisation

DEPSOSVM:variant of differential evolution based on PSO for image and text data classification

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International Journal of Intelligent Computing and Cybernetics 2020年第2期13卷 223-238页

作者： abhishek Dixit Ashish Mani Rohit Bansal Department of Computer Science Amity University Uttar PradeshNoidaIndia Department of EEE Amity University Uttar PradeshNoidaIndia Department of Management Studies Rajiv Gandhi Institute of Petroleum TechnologyRae BareliIndia

Purpose-Feature selection is an important step for data pre-processing specially in the case of high dimensional data *** of the data model is reduced if the model is trained with high dimensional data set,and it results in poor classification ***,before training the model an important step to apply is the feature selection on the dataset to improve the performance and classification ***/methodology/approach-A novel optimization approach that hybridizes binary particle swarm optimization(BPSO)and differential evolution(DE)for fine tuning of SVM classifier is *** name of the implemented classifier is given as ***-This approach is evaluated using 20 UCI benchmark text data classification data ***,the performance of the proposed technique is also evaluated on UCI benchmark image data set of cancer *** the results,it can be observed that the proposed DEPSOSVMtechniques have significant improvement in performance over other algorithms in the literature for feature *** proposed technique shows better classification accuracy as ***/value-The proposed approach is different from the previous work,as in all the previous work DE/(rand/1)mutation strategy is used whereas in this study DE/(rand/2)is used and the mutation strategy with BPSO is *** difference is on the crossover approach in our case as we have used a novel approach of comparing best particle with sigmoid *** core contribution of this paper is to hybridize DE with BPSO combined with SVM classifier(DEPSOSVM)to handle the feature selection problems.

关键词： Support vector machine(SVM) Differential evolution(DE) Particle swarm optimization(PSO)and Global optimization

Microstructure, precipitates and mechanical properties of powder bed fused inconel 718 before and after heat treatment

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Journal of Materials Science & Technology 2019年第6期35卷 1153-1164页

作者： Le Zhou abhishek Mehta Brandon McWilliams Kyu Cho Yongho Sohn Advanced Materials Processing and Analysis Center University of Central Florida Orlando FL 32816 USA Department of Materials Science and Engineering University of Central Florida Orlando FL 32816 USA Weapons and Materials Research Directorate US. Amy Research Laboratory Aberdeen Proving Ground MD 21005 USA

IN718 alloy was fabricated by laser powder bed fusion(PBF) for examination of microstructure, precipitates and mechanical properties in the as-built state and after different heat treatments. The as-built alloy had a characteristic fine cellular-dendritic microstructure with Nb, Mo and Ti segregated along the interdendritic region and cellular boundary. The as-built alloys were then subjected to solution heat treatment(SHT) at 980°C or 1065°C for 1 h. SHT at 980°C led to the formation of δ-phase in the interdendritic region or cellular boundary. The segregation was completely removed by the SHT at 1065°C, but recrystallization was observed, and the carbides decorated along the grain boundaries. The as-built alloy and alloys with SHT at 980°C and 1065°C were two-step aged, which consisted of annealing at 720°C for8 h followed by annealing at 620°C for 8 h. Transmission electron microscopy revealed the precipitation of λ’ and λ" in all alloys after two-step aging, but the amount and uniformity of distribution varied. The Vickers hardness of the PBF IN718 alloy increased from 296 HV to 467 HV after direct aging. The hardness decreased to 267 HV and 235 HV after SHT at 980°C and 1065°C, respectively, but increased to 458 HV and 477 HV followed by aging. The evolution of Young’s modulus after heat treatment exhibited similar trend to that of hardness. The highest hardness was observed for IN718 after SHT at 1065°C and two-step aging due to precipitation with greater amount and uniform distribution.

关键词： Laser powder bed fusion IN718 Microstructure Transmission electron microscopy

Strategies for fitting accurate machine-learned inter-atomic potentials for solid electrolytes

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Materials Futures 2023年第1期2卷 145-156页

作者： Juefan Wang abhishek A Panchal Pieremanuele Canepa Department of Materials Science and Engineering National University of Singapore9 Engineering Drive 1117575Singapore Department of Chemical and Biomolecular Engineering National University of Singapore4 Engineering Drive 4117585Singapore

Ion transport in materials is routinely probed through several experimental techniques,which introduce variability in reported ionic diffusivities and *** computational prediction of ionic diffusivities and conductivities helps in identifying good ionic conductors,and suitable solid electrolytes(SEs),thus establishing firm structure-property ***-learned potentials are an attractive strategy to extend the capabilities of accurate ab initio molecular dynamics(AIMD)to longer simulations for larger systems,enabling the study of ion transport at lower ***,machine-learned potentials being in their infancy,critical assessments of their predicting capabilities are ***,we identified the main factors controlling the quality of a machine-learning potential based on the moment tensor potential formulation,when applied to the properties of ion transport in ionic conductors,such as *** results underline the importance of high-quality and diverse training sets required to fit moment tensor *** highlight the importance of considering intrinsic defects which may occur in *** demonstrate the limitations posed by short-timescale and high-temperature AIMD simulations to predict the room-temperature properties of materials.

关键词： solid electrolytes solid-state batteries lithium-ion batteries ionic conductors machine-learning potentials molecular dynamics density functional theory

Virtual preoperative planning and 3D printing are valuable for the management of complex orthopaedic trauma

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Chinese Journal of Traumatology 2019年第6期22卷 350-355页

作者： abhishek Mishra Tarun Verma abhishek Vaish Riya Vaish Raju Vaishya Lalit Maini Department of Orthopaedics and Joint Replacement Surgery Maulana Azad Medical CollegeLok Nayak HospitalNew Delhi 110001India Department of Orthopaedics and Joint Replacement Surgery Indraprastha Apollo HospitalSaritaViharNew Delhi 110076India

Purpose:The technology of 3D printing(3DP)exists for quite some time,but it is still not utilized to its full potential in the field of orthopaedics and traumatology,such as underestimating its worth in virtual preoperative planning(VPP)and designing various models,templates,and *** can be a significant tool in the reduction of surgical morbidity and better surgical outcome avoiding various associated ***:An observational study was done including 91 cases of complex trauma presented in our institution requiring operative *** preoperative planning and 3DP were used in the management of these *** managing these cases were given a set of questionnaire and responses were recorded and assessed as a quantitative ***:In all the 91 cases,where VPP and 3DP were used,the surgeons were satisfied with the outcome which they got intraoperatively and *** time was reduced,with a better *** dimensional models of complex fracture were helpful in understanding the anatomy and sketching out the plans for optimum reduction and *** average score of the questionnaire was 4.5,out of a maximum of 6,suggesting a positive role of 3DP in ***:3DP is useful in complex trauma management by accurate reduction and placement of implants,reduction of surgical time and with a better *** there is an initial learning curve to understand and execute the VPP and 3DP,these become easier with practice and experience.

关键词： Three-dimensional printing Bone fractures Fracture dislocation X-ray computed tomography

Design and development of a high-performance Ni-based superalloy WSU 150 for additive manufacturing

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Journal of Materials Science & Technology 2020年第12期47卷 20-28页

作者： Praveen Sreeramagiri Ajay Bhagavatam abhishek Ramakrishnan Husam Alrehaili Guru Prasad Dinda Department of Mechanical Engineering Wayne State UniversityDetroitMl48202USA

This research proposes a design and development strategy of a new nickel-based superalloy for additive manufacturing.A new Ni-based superalloy has been developed by the application of the combinatorial alloy development technique coupled with CALPHAD based solidification modeling by effectively suppressing the precipitation *** suppression of precipitation during processing paved a way for prevention of cracks during *** new alloy "WSU 150" revealed excellent room temperature mechanical properties with a yield strength of 867 MPa,an ultimate tensile strength of 1188 MPa,and an elongation of 27.9% in the as-deposited *** mechanical properties of the heat-treated alloy were improved significantly to 1114 MPa yield strength,1396 MPa ultimate tensile strength,and an elongation of 16.1%.Improvement in the mechanical properties is attributed to the additional precipitation and coarsening of γ’ and carbides during *** investigation of the alloy revealed spherical γ’ with a rippled size distribution from the center to the interdendritic *** average size of the γ’ particles in the as-deposited condition was found to be around 48 nm in the interdendritic ***-treatment promoted the coarsening of γ’ which is explained in the paper.

关键词： Ni-based superalloys Additive manufacturing Laser metal deposition Ripple pattern microstructure Alloy development Mechanical properties