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Facies analysis and paleoenvironmental interpretation of Piacenzian carbonate deposits from the Guitar Formation of Car Nicobar Island,India

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Geoscience Frontiers 2013年第6期4卷 755-764页

作者： amit k.ghosh Suman Sarkar Birbal Sahni Institute of Palaeobotany 53 University RoadLucknow 226 007India

Facies characterization of Piacenzian （late Pliocene） carbonate sediments of the Guitar Formation in Car Nicobar Island,India and the subsequent integration of paleoecological data have been applied to interpret the paleoenvironment of the coralline algal-reef ***-section analysis reveals that Amphiroa,Corallina and Jania are the dominant geniculate corallines,while Lithothamnion,Mesophyllum,Phymatolithon,Lithophyllum,Spongites and Lithoporella are the major non-geniculate corallines contributing to the sedimentary *** small and larger benthic foraminifera also dominate the biogenic ***,barnacle shells,echinoid spines,fragments of bryozoans,mollusks and ostracodes are the subordinate *** dominate the studied facies while packstones and boundstones （with wackestone elements） are the sub lithofacies showing a fair *** carbonate facies presenting a complete reef complex have been distinguished that were deposited in shallow intertidal,back-reef shelf/lagoon,reef and deeper fore-reef shelf *** of coralline algal and benthic foraminiferal assemblages,taphonomic signatures of abrasion and fragmentation,grain size,angularity and encrustation indicate a shallow to relatively deeper bathymetric horizon of approximately 10-60 m that corresponds to a regime of high to moderate hydrodynamic conditions.

关键词： Facies analysis Coralline algae Benthic foraminifera Piacenzian Guitar Formation Car Nicobar

Improvement of warm formability of Al-Mg sheet alloys containing coarse second-phase particles

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中国科学:技术科学 2010年第4期40卷 434-434页

作者： Arne k DAHLE amit k ghosh Materials Engineering University of Queensland Department of Materials Science and Engineering University of Michigan

Several alloying elements involving Zr,Cu,Zn and Sc were added to Al-Mg sheet alloys in order to obtain an excellent combination of high strength and good high-temperature *** examination showed that coarse intermetallic particles were formed in the microstructure and their amounts changed with variations of the alloying elements. During warm rolling of thermomechanical treatments prior to warm deformation,the coarse particles initiated cracks,decreasing the warm *** healing the crack damage and further improving the warm formability,a process of hot isothermal press was developed and optimized to the sheet *** this process,the biaxial stretch formability at 350°C was improved by 22%for an aluminum alloy containing a large amount of coarse particles.

关键词： aluminum alloy microstructure second-phase particle hot isothermal press high-temperature formability

Oldest Asian Record of Snapping Shrimps(Malacostraca:Alpheidae)from the kutch Basin,Western India and Associated Biota:Biostratigraphic,Paleoenvironmental and Paleoecological Significance

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Acta Geologica Sinica(English Edition) 2022年第6期96卷 1867-1883页

作者： Vivesh V.kAPUR kamlesh kUMAR Pranav J.PANDYA amit kghosh Arindam CHAkRABORTY Anupam SHARMA Gaurav CHAUHAN M.G.THAkkAR Birbal Sahni Institute of Palaeosciences 53University RoadLucknow 226007India Department of Biology Shri R.R.Lalan CollegeBhujKachchh DistrictGujaratIndia Institute of Earth Sciences Academia SinicaTaipeiTaiwan 11529China Department of Earth and Environmental Science K.S.K.V.Kachchh UniversityBhujKachchh DistrictGujaratIndia

The oldest Asian record of alpheid shrimps,assigned to genus Alpheus,based on snapping claw fingertips from the Miocene khari Nadi Formation in the kutch Basin,western India reported herein,extends the fossil record of the family Alpheidae from Asia by~22 million *** early Miocene(Aquitanian)age is estimated based on the associated assemblage of calcareous nannofossils,Sphenolithus disbelemnos,Cyclicargolithus floridanus,and Reticulofenestra *** co-occurring microbiota includes bony fish otolith remains,identified as“genus Gobiidarum”,isolated teeth of Dasyatis rays,Sphyrna sharks,and teleosts,ctenoid and placoid scales,ostracods,belonging to the genera Paractinocythereis,Alocopocythere,Ruggieria,Aglaiocypris,Bairdoppilata,and echinoid *** together,the microfossil assemblage and data from chemical analyses using Energy Dispersive Spectroscopy,X-Ray Diffraction and Wavelength Dispersive X-Ray Fluorescence of host and associated lithologies suggests prevalence of a shallow(neritic)to coastal marine(intertidal)depositional *** present investigation also provides the oldest fossil evidence on the co-occurrence of Alpheus and gobiids(based on otoliths)that strongly advocates that the mutualistic association between these animal groups had developed by the Aquitanian.

关键词： biostratigraphy Crustacea Caridea Elasmobranchs Gobiidae invertebrate and vertebrate paleontology nannofossils Oligocene-Miocene Indian subcontinent

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Preface

Science China(Physics,Mechanics & Astronomy) 2010年第6期53卷 976-976页

作者： Arne k DAHLE amit k ghosh Materials Engineering University of Queensland Department of Materials Science and Engineering University of Michigan

关键词： aluminum alloy microstructure second-phase particle hot isothermal press high-temperature formability

Multi-criteria land evaluation for suitability analysis of wheat:a case study of a watershed in eastern plateau region,India

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Geo-Spatial Information Science 2014年第2期17卷 119-128页

作者： Aditi SARkAR amit ghosh Pabitra BANIk Agricultural and Ecological Research Unit Indian Statistical Institute203B.T.RoadKolkata 700108India

Improper land use results in land degradation as well as decline in agricultural *** obtain optimum benefit from the land,proper utilization of its resources is *** suitability analysis is the evaluation and grouping of specific areas of land in terms of their suitability for a defined use,which is a precondition for sustainable land use *** study investigated the applicability of Geographical Information System(GIS)techniques in combination with multi-criteria land evaluation for analysing land *** study used the weighted overlay technique for multi-criteria evaluation with GIS for the assessment of suitability of wheat cultivation in Beko watershed(Purulia,India).The watershed area is moderately suitable for wheat crop production,with constraints like imperfect drainage and poor soil depth.

关键词： spatial analysis GIS remote sensing multi-criteria decision analysis spatial decision support system

Influence of Cold Deformation on the Aging Behaviour of Al-Cu-Si-Mg Alloy

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Journal of Materials Science & Technology 2011年第3期27卷 193-198页

作者： S.k.ghosh Department of Metallurgy and Materials Engineering Bengal Engineering and Science University

The present study deals with the effect of cold deformation and subsequent aging on the microstructure and mechanical properties of AI-Cu-Si-Mg alloy. Differential scanning calorimetry indicates that precipitation occurs in the temperature range of 258-272℃ for the as quenched wrought alloy. The activation energy value estimated by kissinger method for the aforesaid precipitation reaction is obtained as 106 kJ/mol. 45% cold deformation prior to aging indicates the first dissolution reaction at about 50℃ and the precipitation reaction at a temperature of about 82℃. Microstructural investigations have revealed the formation of fine precipitates within the matrix after aging of the cold deformed sample. As-quenched alloy reveals prominently the aging response, The increase in hardness, yield and tensile strength with simultaneous decrease in elongation in the deformed alloy is found to be primarily due to the deformation strengthening and not due to the precipitation hardening.

关键词： Aluminium alloy Aging Cold deformation Differential scanning calorimetry kissinger method

Data-Driven Approaches for Spatio-Temporal Analysis:A Survey of the State-of-the-Arts

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Journal of Computer Science & Technology 2020年第3期35卷 665-696页

作者： Monidipa Das Soumya k.ghosh School of Computer Science and Engineering Nanyang Technological UniversitySingapore 639798Singapore Department of Computer Science and Engineering Indian Institute of Technology KharagpurKharagpur 721302India

With the advancement of telecommunications,sensor networks,crowd sourcing,and remote sensing technology in present days,there has been a tremendous growth in the volume of data having both spatial and temporal *** huge volume of available spatio-temporal(ST)data along with the recent development of machine learning and computational intelligence techniques has incited the current research concerns in developing various data-driven models for extracting useful and interesting patterns,relationships,and knowledge embedded in such large ST *** this survey,we provide a structured and systematic overview of the research on data-driven approaches for spatio-temporal data *** focus is on outlining various state-of-the-art spatio-temporal data mining techniques,and their applications in various *** start with a brief overview of spatio-temporal data and various challenges in analyzing such data,and conclude by listing the current trends and future scopes of research in this multi-disciplinary *** with other relevant surveys,this paper provides a comprehensive coverage of the techniques from both computational/methodological and application *** anticipate that the present survey will help in better understanding various directions in which research has been conducted to explore data-driven modeling for analyzing spatio-temporal data.

关键词： data-driven modeling spatio-temporal data prediction change pattern detection outlier detection hotspot detection partitioning/summarization (tele-)coupling visual analytics

Diversity of Middle Eocene Coralline Red Algae from the Prang Limestone(Shella Formation) of Jaintia Hills, Meghalaya, NE Himalaya, India with special emphasis on palaeoenvironment

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科学通报 2013年第S1期58卷 118-125页

作者： ghosh amit kumar SARMA Ajanta SARkAR Suman Birbal Sahni Institute of Palaeobotany Department of Geology GC College

Palaeocene-Eocene carbonates of shallow marine sequence belonging to Shella Formation of Jaintia Group are well developed in the south of the Jaintia Hills, Meghalaya and represent an excellent outcrop of shelf sediments in North Eastern Himalaya, India. These outcrops are exposed along the southern fringe of Shillong Plateau. The Prang Limestone is the uppermost lithostratigraphic unit of the Shella Formation within the Jaintia Group. It is overlain by sand-shale alternation of the kopili Formation and underlain by the Narpuh Sandstone. A rich assemblage of larger foraminifera including Nummulites, Discocyclina etc. has been recorded earlier from the Prang Limestone and based on the foraminiferal assemblage, a Middle Eocene to Early Late Eocene age has been assigned to the Prang Limestone. Thin section analysis of the Prang Limestone revealed the abundance of well preserved coralline red algae along with other well preserved and significant biogenic elements. Morpho-taxonomical study reveals that the algal flora is represented by seven species belonging to the families Hapalidiaceae(Subfamily: Melobesioideae), Corallinaceae(Subfamily: Mastophoroideae) and Sporolithaceae. The dominance of melobesioid and mastophoroid forms is the characteristic feature of this algal assemblage. Coralline algae occur mostly in encrusting growth form with orbitoid foraminifera and occasionally the coralline algae form rhodoliths. On this basis of algal forms it can be inferred that they thrived in a shallow, warm, shelf environment of normal salinity.

关键词： diversity Coralline algae taxonomy Middle Eocene Shella Formation Meghalaya NE Himalaya India

Minimum energy optimal external torque control of human binocular vision

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Control Theory and Technology 2020年第4期18卷 431-458页

作者： Bijoy k.ghosh Bhagya Athukorallage Department of Mathematics and Statistics Texas Tech UniversityLubbockTX 79409-1042USA School of Automation Engineering University of Electronic Science and Technology of ChinaChengduSichuan 610054China

In this paper,we consider eyes from the human binocular system,that simultaneously gaze on stationary point targets in space,while optimalal skipping from one target to the next,by rotaing their individual gaze *** head is assume fixed on the torso and the rotaing gaze direction of the two eyes are assumed restricted to pass through a point in the visual *** is further assumed that,individullly the rotations of the two eyes satisfy the well known Listing's *** formulate and study acombined optimal gaze rotation for the two eyes,by constructing a single Riemanmian metric,on the asociaced parameter *** goal is to optimally rotate so that the convergent gaze changes between two pre-specified target points in a finite time interval[0,1].The cost function we choose is the total energy,measured by the L2?norm,of the six extenal torques on the binocular *** torque functions are synthesized by solving an associated*two-point boundary value *** paper demonstrates,via simulation,the shape of the optimal gaze trajectory of the focused point of the bin-ocular *** Euclidean distance between the initial and the final point is compared to the arc:length of the optimal *** consumed *** computed for diferent eye movement chores and discussed in the *** simulation we observe that certain eye movement maneuvers are energy fficicnt and demonstrate that the optimal external torque is a linear function in *** also explore and conclude that spitting an arbitry opimal eye movement into optimal vergence and version components is not energy fficient although this is how the human oculomotor control seems to *** gaze tajectories and opimal extermal torque functions reported in this paper is new.

关键词： Binocular vision Riemamian gcometry Optimal control Human eye movement