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Journal of Palaeogeography 2017年第4期6卷 321-332页

作者： Matthias Alberti Dhirendra k.pandey Jitendra k.Sharma Narendra k.Swami Alfred Uchman Institut für Geowissenschaften Christian-Albrechts-Universitt zu Kiel Department of Geology University of Rajasthan Earth & Planetary Sciences Group/Palaeontology Manipal Center for Natural Sciences Manipal University Institute of Geological Sciences Jagiellonian University

A spectacularly exposed slump is described from a 120-m-long road cut between the villages of kanod and Deva in the northeastern Jaisalmer Basin of rajasthan,*** Upper Jurassic part of the sediments at the outcrop was formed in a near-shore setting and belongs to the Ludharwa Member of the Baisakhi *** 3-m-thick unit shows a number of asymmetric folds and thrust faults leading to an imbrication of partly lithified sandstone *** deformation structures allow the reconstruction of a movement towards the *** agrees well with the basin configuration that shows a deepening into this *** the determination of a specific trigger mechanism is difficult for soft-sediment deformation structures,an earthquake caused by synsedimentary tectonics in the basin seems to be the most likely explanation.

关键词： Sedimentology Mass movements Slumping Soft-sediment deformation structures Jaisalmer Basin Jurassic

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

Microstructure,mechanical and wear properties of aluminum borate whisker reinforced aluminum matrix composites

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Transactions of Nonferrous Metals Society of China 2020年第7期30卷 1731-1742页

作者： Neeraj pandey ICHAkrABArTY kalpana BArkANE NSMEHTA MrMAJHI Department of Ceramic Engineering Indian Institute of Technology(BHU)VaranasiU.P.India Department of Metallurgical Engineering Indian Institute of Technology(BHU)VaranasiU.P.India

The microstructural features and the consequent mechanical properties were characterized in aluminium borate whisker(ABOw)(5, 10 and 15 wt.%) reinforced commercially-pure aluminium composites fabricated by conventional powder metallurgy technique. The aluminium powder and the whisker were effectively blended by a semi-powder metallurgy method. The blended powder mixtures were cold compacted and sintered at 600 ℃. The sintered composites were characterized for microstructural features by optical microscopy(OM), scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS), transmission electron microscopy(TEM) and X-ray diffraction(XrD) analysis. Porosity in the composites with variation in ABOw contents was determined. The effect of variation in content of ABOw on mechanical properties, viz. hardness, bending strength and compressive strength of the composites was evaluated. The dry sliding wear behaviour was evaluated at varying sliding distance at constant loads. Maximum flexural strength of 172 MPa and compressive strength of 324 MPa with improved hardness around HV 40.2 are obtained in composite with 10 wt.% ABOw. Further increase in ABOw content deteriorates the properties. A substantial increase in wear resistance is also observed with 10 wt.% ABOw. The excellent combination of mechanical properties of Al-10 wt.%ABOw composites is attributed to good interfacial bonds, less porosity and uniformity in the microstructure.

关键词： aluminum matrix composite powder metallurgy aluminum borate whisker(ABOw)reinforcement flexural strength compression test dry sliding wear

Preparation,characterization and thermophysical properties investigation of A70/polyaniline nanocomposite phase change material for medium temperature solar applications

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能源与人工环境(英文) 2021年第3期2卷 271-277页

作者： A.k.pandey Mathew George Nasrudin Abd rahim V.V.Tyagi Syed Shahabuddin r.Saidur research Centre for Nano-Materials and Energy Technology(rCNMET) School of Science and TechnologySunway UniversityNo.5Jalan UniversitiBandar SunwayPetaling Jaya47500 Selangor Darul EhsanMalaysia Higher Institution Centre of Excellence(HICoE) UM Power Energy Dedicated Advanced Centre(UMPEDAC)Level 4Wisma R&DUniversity of MalayaJalan Pantai Baharu59990 Kuala LumpurMalaysia renewable Energy research Group King Abdulaziz UniversityJeddah 21589Saudi Arabia School of Energy Management Shri Mata Vaishno Devi UniversityKatra 182320(J&K)India Department of Science School of TechnologyPandit Deendayal Petroleum UniversityKnowledge CorridorRaisan VillageGandhinagar 382007GujratIndia

The ever-present demand for energy from various application in industrial and domestic processes has led to the consumption of fossil fuel at a rapid rate with adverse effect due to global *** study focuses on the thermal energy storage aspect intended for medium temperature applications.A novel composite A70 and PANI was prepared and *** study investigates the composites thermophysical and optical *** Scanning Calorimetry and Transient Hot Bridge measured thermal storage capacity and thermal conductivity of the composite,*** heat storage capacity of the composite remained stable within 4%whereas a highest rise of 11.96%in thermal conductivity was *** composites thermal,chemical,and physical stability were analysed from Thermogravimetric Analyser,Fourier Infrared Transform,and Scanning Electron Microscope,*** composites were thermally stable up to a temperature of 250°*** chemical reaction occurred between the nanomaterial and base PCM *** microscopic visuals did not show any considerable change in the microscopic structure of the *** the case of optical properties,the composites showed significant reduction in transmittance of solar spectrum with respect to pure *** maximum decrement in transmission was around~89%compared to *** the composite prepared were thermally stable till 250°C,hence may be utilized for solar thermal and low concentrated photovoltaic application but not limited to these.

关键词： Phase change materials Solar energy Thermal conductivity Latent heat Polyaniline

A New Stable Algorithm to Compute Hankel Transform Using Chebyshev Wavelets

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Communications in Computational Physics 2010年第7期8卷 351-373页

作者： rajesh k.pandey Vineet k.Singh Om P.Singh PDPM Indian Institute of Information Technology Design and Manufacturing JabalpurIndia Birla Institute of Technology and Science-Pilani Goa CampusGoaIndia Department of Applied Mathematics Institute of TechnologyBanaras Hindu UniversityVaranasiIndia

A new stable numerical method,based on Chebyshev wavelets for numerical evaluation of Hankel transform,is proposed in this *** Chebyshev wavelets are used as a basis to expand a part of the integrand,r f(r),appearing in the Hankel transform *** transforms the Hankel transform integral into a Fourier-Bessel *** truncating the series,an efficient and stable algorithm is obtained for the numerical evaluations of the Hankel transforms of order ν>−*** method is quite accurate and stable,as illustrated by given numerical examples with varying degree of random noise terms εθ_(i) added to the data function f(r),where θ_(i) is a uniform random variable with values in[−1,1].Finally,an application of the proposed method is given for solving the heat equation in an infinite cylinder with a radiation condition.

关键词： Hankel transforms Bessel functions Chebyshev wavelets random noise term

Alkaline phosphatase as a bio-indicator of phosphorus-eutrophy in freshwater ecosystems: A review

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International Journal of Sediment research 2023年第3期38卷 349-360页

作者： Madhulika Singh Jitendra pandey Ganga river Ecology research Laboratory Environmental Science Division Centre of Advanced Study in Botany Institute of Science Banaras Hindu University

Limnologists have greatly advanced the understanding of indicators of phosphorus(P)-eutrophy in surface waters. Biotic variables such as macro-invertebrates, fish, zooplankton, benthic algae, and diatoms are extensively used for bio-assessment of eutrophy. New concepts highlight the importance of bed-sediment based “response” variables predicting functional shifts during eutrophication. A cross analysis of studies reveals that alkaline phosphatase(ALP), which serves as a proxy of P-deficiency, and also as an indicator of benthic anoxia/hypoxia-driven feedbacks, can be an easy to measure, cost-effective and reliable tool to assess changes in nutrient stoichiometry, trophic status, and ecological functioning at the sediment-water interface. Here, the issues discussed in this paper are highly relevant to explore new domains of research and “response” based ecosystem models for potential eutrophication management decisions. Because ALP is used in molecular cloning and fingerprinting studies, it is suggested that approaches based on the “omics” technologies need to be used to explore more intricate connections to empirically address ALP-P-eutrophy linkages to track eutrophication in freshwater ecosystems.

关键词： Alkaline phosphatase Sediment based-indicators Ecosystem feedback Nutrient stoichiometry Phosphorus-eutrophy

Can we constrain the evolution of HI bias using configuration entropy?

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research in Astronomy and Astrophysics 2021年第2期21卷 82-88页

作者： Biswajit Das Biswajit pandey Department of Physics Visva-Bharati UniversitySantiniketanBirbhum731235India

We study the evolution of the configuration entropy of HI distribution in the post-reionization era assuming different time evolution of HI *** describe time evolution of linear bias of HI distribution using a simple form b(a)=b_(0)a^(n) with different index *** derivative of the configuration entropy rate is known to exhibit a peak at the scale factor corresponding to theΛ-matter equality in the unbiasedΛCDM *** show that in theΛCDM model with time-dependent linear bias,the peak shifts to smaller scale factors for negative values of *** is related to the fact that the growth of structures in the HI density field can significantly slow down even before the onset ofΛdomination in the presence of a strong time evolution of the HI *** find that the shift is linearly related to the index *** obtain the best fit relation between these two parameters and propose that identifying the location of this peak from observations would allow us to constrain the time evolution of HI bias within the framework of theΛCDM model.

关键词： methods analytical-cosmology theory-large scale structure of the universe

Exploration of deep seabed polymetallic sulphides: Scientific rationale and regulations of the International Seabed Authority

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矿业科学技术学报：英文版 2013年第3期23卷 457-462页

作者： Anju pandey Ministry of Earth Sciences Prithvi Bhavan New Delhi 110003 India

Polymetallic sulphides have been consistent source of metals like iron, copper, zinc and lead. Apart from these they are also seen as economically viable resources of silver and gold. As the demand of these metals is showing an astoundingly increasing trend, the search for their resources has also increased in similar folds. This has resulted in many nations' focus on deep seabed resources of the polymetallic sulphides. Consequently, International Seabed Authority (ISBA) has provided 'regulations' to obtain plan of work for exploration of polymetallic sulphide deposits in deep seabed 'Area'. Following the release of these regulations, several countries are in the process of obtaining the licence for exploration of these metals from the deep seabed regions. Detailed information about the science and ISBA regulations for exploration of polymetallic sulphide deposits is prerequisite to submit an application to ISBA for their exploration. The current contribution provides a comprehensive review of the science behind locating polymetallic sulphide deposits in geological setting of deep seabed as well as about the ISBA regulations for their exploration.

关键词： Polymetallic sulphide International Seabed Authority Exploration Mid ocean ridges

Coating of bioactive glass on magnesium alloys to improve its degradation behavior: Interfacial aspects

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Journal of Magnesium and Alloys 2020年第4期8卷 999-1015页

作者： V.S.Yadav M.r.Sankar L.M.pandey centre for the environment indian institute of technology guwahatiassam781039india department of mechanical engineering indian institute of technology guwahatiassam781039india department of mechanical engineering indian institute of technology tirupatiandhra pradesh517506india department of biosciences and bioengineering indian institute of technology guwahatiassam781039india

The preferable mechanical properties of Mg alloys along with excellent compatibility with human bone have established their applicability as implant ***,a higher corrosion/degradation rate of Mg alloys in body fluids limits its biomedical *** this direction,surface modification and coating are explored as appropriate strategies to mode the degradation rate of Mg *** constituents of bioactive glass(BG)provide strength,bio-inertness and bone bonding ***,researchers have explored the coating of BG on Mg alloys and investigated chemical,mechanical and biological properties of the coated *** this review,we have made an attempt to compile the literature works done on the coating of BG on Mg alloys and its *** interfacial aspects of the coated substrates towards the degradation behavior are *** way forward to further improve the coating characteristics of BG coated Mg alloys are remarked.

关键词： Bioactive glass Magnesium alloys Adhesion strength Coating thickness Wettability Degradation

A multiwavelength view of a classical T Tauri star CV Cha

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research in Astronomy and Astrophysics 2019年第1期19卷 75-86页

作者： Jeewan Chandra pandey Subhajeet karmakar Arti Joshi Saurabh Sharma Shashi Bhushan pandey Anil kumar pandey Aryabhatta research Institute of Observational Sciences (ArIES)

Using long-term optical, ultraviolet(UV) and X-ray data, we present a study of a classical T Tauri star CV Cha. The V-band light curve obtained from the All Sky Automated Survey(ASAS) shows short as well as long-term variability. The short-term variability could be due to rotational modulation of CV Cha. We derive the rotational period of 3.714 ± 0.001 d for CV Cha. UV light curves obtained from Swift also show the variations. X-ray light curves from XMM-Newton and Swift do not show any significant short as well as long-term variability. However, the light curve from Chandra appears to be variable, which could be due to the emergence of flaring activities. X-ray spectra from all observations are explained well by the single temperature plasma of 0.95 keV with X-ray luminosity of 1030.4erg s-1in the 0.5–7.5 keV energy band. It appears that variability in optical and UV bands could be due to the presence of both hot and cool spots on the surface, while X-ray emission is dominated by magnetic processes.

关键词： stars:activity stars:individual(CV Cha) stars:pre-main sequence stars:variable:T Tauri X-ray:stars