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Improvement of Deep Groove Ball Bearing’s Performance Using a Bionic Textured Inner Race

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Journal of Bionic Engineering 2021年第4期18卷 974-990页

作者： k.E.Ch.Vidyasagar R.k.pandey Dinesh kalyanasundaram Center for Biomedical Engineering Indian Institute of Technology DelhiNew Delhi110016India Department of Biomedical Engineering College of EngineeringOsmania UniversityHyderabad500007India Department of Mechanical Engineering Indian Institute of Technology DelhiNew Delhi110016India Department of Biomedical Engineering All India Institute of Medical SciencesNew Delhi110029India

Micro-textured surfaces have improved the tribological performance of contact surfaces under lubricated conditions;however,not practiced due to manufacturing *** addition to simpler micro-pits or straight-trench type textures,sophisticated bioinspired textures on commercial radial ball bearings have been scarcely *** this work,Dendroaspis polylepis(Mamba snake)skin-type textures were fabricated on the inner race of FAG radial ball bearings using a nanosecond fiber laser *** the snake textures were primarily meant to enhance friction,the dimensions of the texture have been carefully chosen to improve the tribological performance under lubricated *** textured bearings were assembled and experimented at various rotational speeds and lightly loaded conditions to measure vibrational amplitude,frictional torque,and temperature *** to untextured(conventional)bearing,the snake-skin type textured bearings resulted in improved tribo-dynamic performance.

关键词： bionic texture radial ball bearing frictional torque vibration temperature

Digitally controlled oscillator design with a variable capacitance XOR gate

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Journal of Semiconductors 2011年第10期32卷 86-92页

作者： Manoj kumar Sandeep k.Arya Sujata pandey Department of Electronics and Communication Engineering Guru Jambheshwar University of Science and TechnologyHisarIndia Amity University NoidaIndia

A digitally controlled oscillator（DCO） using a three-transistor XOR gate as the variable load has been presented.A delay cell using an inverter and a three-transistor XOR gate as the variable capacitance is also proposed. Three-,five- and seven-stage DCO circuits have been designed using the proposed delay *** output frequency is controlled digitally with bits applied to the delay *** three-bit DCO shows output frequency and power consumption variation in the range of 3.2486-4.0267 GHz and 0.6121-0.3901 mW,respectively,with a change in the control word *** five-bit DCO achieves frequency and power of 1.8553-2.3506 GHz and 1.0202-0.6501 mW,respectively,with a change in the control word ***,the seven-bit DCO shows a frequency and power consumption variation of 1.3239-1.6817 GHz and 1.4282-0.9102 mW,respectively, with a varying control word *** power consumption and output frequency of the proposed circuits have been compared with earlier reported circuits and the present approaches show significant improvements.

关键词： digital control oscillator delay cell power consumption variable capacitance voltage controlled oscillators XOR gate

Activator-assisted electroless deposition of copper nanostructured films

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International Journal of Minerals,Metallurgy and Materials 2014年第2期21卷 196-203页

作者： Varsha R. Mehto R. k. pandey Department of Physics Barkatullah University NIIT University

This paper showed simple and effective synthesis of copper nanoparticles within controlled diameter using direct electroless deposition on glass substrates, following the sensitization and activation steps. Electroless-deposited metals, such as Cu, Co, Ni, and Ag, and their alloys had many advantages in micro- and nanotechnologies. The structural, morphological, and optical properties of copper deposits were characterized using X-ray diffraction （XRD）, atomic force microscopy （AFM）, and UV-Vis spectroscopy. The structural data was further analyzed using the Rietveld refinement program. Structural studies reveal that the deposited copper prefers a （111） orientation. AFM studies suggest the deposited materials form compact, uniform, and nanocrystalline phases with a high tendency to self-organize. The data show that the particle size can be controlled by controlling the activator concentration. The absorption spectra of the as-deposited copper nanoparticles reveal that the plasmonic peak broadens and exhibits a blue shift with decreasing particle size.

关键词： nanostructured materials thin films copper electroless plating deposition

Lysimeter based crop coefficients for estimation of crop evapotranspiration of black gram (Vigna Mungo L.) in sub-humid region

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International Journal of Agricultural and Biological Engineering 2011年第4期4卷 50-58页

作者： Pankaj k.pandey Vanita pandey Department of Agricultural Engineering North Eastern Regional Institute of Science&TechnologyNirjuli Itanagar Arunachal PradeshIndia Department of Soil&Water Engineering. College of Agricultural Engineering&Post Harvest TechnologyCentral Agricultural UniversityGangtokSikkimIndia

Black gram is dominant pulse crop of the *** coefficient is an important parameter,which needs to be determined for accurate estimates of the crop water *** coefficient,the ratio of potential crop evapotranspiration to reference evapotranspiration,is an important parameter in irrigation planning and ***,this information is not available for many important crops in the study region.A study was undertaken to develop crop coefficients for black gram crop,and a comparison is made of single and dual crop coefficient approaches to estimate actual crop evapotranspiration under the climatic conditions of Udaipur,*** coefficient was developed from daily measured black gram evapotranspiration(ETBG)data by electronic weighing lysimeter and reference evapotranspiration calculated using standard Penman-Monteith *** measured values of crop coefficient for the crop were 0.48,1.18 and 0.33 during initial,mid-season and late-season *** evaluation of different approaches showed that daily ETBG estimate based on dual crop coefficient method have been found best(SE=0.40,r=0.96).Furthermore,a quadratic curve(second-order polynomial)method were fitted well(SE=0.47,r=0.94)to predict crop coefficient values as function of days after sowing(DAS).These locally developed and evaluated values can be used for proper irrigation planning in water scarcity area of Udaipur and other areas with similar agro-ecological conditions.

关键词： lysimeter evapotranspiration crop coefficient electronic weighing lysimeter reference evapotranspiration black gram(Vigna Mungo L.) irrigation

Microstructure studies of air-plasma-spray-deposited CoNiCrAlY coatings before and after thermal cyclic loading for high-temperature application

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International Journal of Minerals,Metallurgy and Materials 2016年第8期23卷 934-942页

作者： Dipak kumar k.N.pandey Dipak kumar Das Mechanical Engineering Department Motilal Nehru National Institute of TechnologyAllahabad-211004India Defense Metallurgical Research Laboratory Hyderabad-500058India

In the present study, bond-coats for thermal barrier coatings were deposited via air plasma spraying（APS） techniques onto Inconel 800 and Hastelloy C-276 alloy substrates. Scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, X-ray diffraction（XRD）, and atomic force microscopy（AFM） were used to investigate the phases and microstructure of the as-sprayed, APS-deposited Co Ni Cr Al Y bond-coatings. The aim of this work was to study the suitability of the bond-coat materials for high temperature applications. Confirmation of nanoscale grains of the γ/γ′-phase was obtained by TEM, high-resolution TEM, and AFM. We concluded that these changes result from the plastic deformation of the bond-coat during the deposition, resulting in Co Ni Cr Al Y bond-coatings with excellent thermal cyclic resistance suitable for use in high-temperature applications. Cyclic oxidative stability was observed to also depend on the underlying metallic alloy substrate.

关键词： thermal barrier coatings coating structure plasma spraying thermal cycle high-temperature applications microstructure studies

Recurrent hardgrounds and their significance for intra-basinal correlations:a case study of upper Bathonian rocks from the western margin of the Indian craton

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Journal of Palaeogeography 2019年第1期8卷 19-30页

作者： Dhirendra k.pandey Franz T.Fürsich Matthias Alberti Jitendra k.Sharma Narendra Swami Earth and Planetary Sciences Group Manipal Center for Natural SciencesCentre of Excellence Dr. TMA Pai Planetarium Building Manipal Academy of Higher Education FG Pal?oumwelt GeoZentrum Nordbayern Friedrich-Alexander Universit?t Erlangen-Nürnberg Institut für Geowissenschaften Christian-Albrechts-Universit?t zu Kiel Department of Geology University of Rajasthan Himalayan Geology Division Geological Survey of India Northern Region

A set of two to three prominent hardgrounds can be traced for more than 40 km from east to west within the Jurassic succession of the Jaisalmer Basin at the western margin of the Indian Craton. The hardgrounds started to form under subtidal conditions in a mixed carbonate–siliciclastic setting during the last phase of a transgressive systems tract, i.e. the maximum flooding zone. The age difference between the hardgrounds is very small, but they differ lithologically. Typically, the stratigraphically oldest hardground occurs at the top of a 1-m-thick calcareous sandstone. It is characterized by a spectacular megaripple surface encrusted with oysters and subsequently occasionally bored by bivalves. The hardground is overlain by 10–25 cm of biowackestone to biopackstone, at the top of which another hardground is developed. This second hardground is characterized by abundant bivalve(Gastrochaenolites isp.) and "worm" borings(Trypanites and Meandropolydora isp.) and occasional oyster encrustations. The third hardground can be found within the overlying 60-cm-thick, bioturbated, fossiliferous silty marly packstone. It shows common to abundant oyster encrustations and occasional borings together with reworked concretions. The individual hardground can be well recognized throughout the basin based on lithology and biotic components. The second hardground(biowackestone to biopackstone) with abundant bivalve and worm borings is most prominent and widespread. Lithostratigraphically, these three hardground surfaces belong to the uppermost part of the Bada Bag Member of the Jaisalmer Formation. Based on ammonites, such as Perisphinctes congener(Waagen), brachiopods, and corals, this interval of the Bada Bag Member has been assigned a late Bathonian age. The entire succession above the first hardground is bioturbated up to the overlying marly silt of the kuldhar Member of the Jaisalmer Formation, which is already Callovian in age. The characteristic hardground lithologies, toget

关键词： Hardgrounds Stratigraphy Palaeoenvironment Jurassic Jaisalmer Basin

Mechanism of crustal extension in the Laxmi Basin,Arabian Sea

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Geodesy and Geodynamics 2015年第6期6卷 409-422页

作者： pandey Anju pandey Dhananjai k ESSO-National Centre for Antarctic and Ocean Research Ministry of Earth Sciences

Continental rifting and magmatism has been extensively studied worldwide as it is believed that continental rifting, break up of continents and associated magmatism lead to genesis of new oceanic crust. However, various regions of the world show that these processes may lead to genesis of other types of crust than the oceanic crust. Laxmi Basin in the western continental margin of the India is one such region with an enigmatic *** to its extreme strategic significance for the palaeogeographic reconstruction of continents during Cretaceous continental breakup of India, this basin has attracted various workers for more than two decades. However, still the issue of nature of crust in the basin remains controversial. In this contribution, in order to identify nature of crust, mechanism of continental extension in the Laxmi Basin has been studied for the first time through newly acquired seismic data from the basin. Here, we propose a plausible mechanism of crustal extension in the Laxmi Basin which eventually constrains the nature of crust of the Laxmi Basin. We have demonstrated that the crust in the Laxmi Basin can be categorised in two zones of stretched and transitional crust. In the stretched zone several fault bounded horst and graben structures are identified which preserve syn- and post-rift sediments along with different periods of hiatus in sedimentations as unconformities. These faults are identified as listric faults in the upper crust which sole out in the detachment *** faults decouples the upper brittle and lower ductile crust. The transitional crust is identified as heavily intruded by sills and basaltic volcanic which were emplaced due to melting of subcontinental mantle（SCM） after hyper-stretching of crust and serpentinisation of the SCM. Panikkar Ridge is proposed to be one such basaltic volcanic body derived from melting of lower part of the SCM.

关键词： Laxmi Basin Panikkar Ridge Continental extension Mantle exhumation Detachment surface

Sintered Fe-0.8%C-1.0%Si-0.4%Cu P/M Steel Preform Behaviour During Cold Upsetting

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Journal of Iron and Steel Research International 2008年第5期15卷 81-87页

作者： A Rajeshkannan k S pandey S Shanmugam R Narayanasamy Thiagarajar College of Engineering ThiruparankundramMadurai 625015Tamil NaduIndia Maulana Azad National Institute of Technology Bhopal 462007Madhya PradeshIndia Department of Mechanical Engineering National Institute of TechnologyTiruchirappalli 620015Tamil NaduIndia Department of Production Engineering National Institute of TechnologyTiruchirappalli 620015Tamil NaduIndia

Cold upsetting experiments were carried out on sintered Fe 0.8%C1.0%Si-0. 4%Cu steel preforms in order to evaluate their deformation characteristics. Powder preforms of 86 % of theoretical density, with two different ratios of height to diameter, were prepared using a suitable die set assembly on a 1.0 MN capacity hydraulic testing machine. Sintering was carried out in an electric muffle furnace for 1.5 h at 1 150 ℃. Each sintered compact was subjected to incremental loading of 0.04 MN under dry friction condition till a crack appeared at the free surfaces. The experimental results were critically analysed, the stress as a function of strain and densification was obtained, then the work hardening behaviour was analyzed. It has been found that in the process of enhancing densification, strength and strain hardening is also induced during upsetting, but the work hardening behaviour is not homogenously enhanced against strain and densification.

关键词： cold upsetting stress height strain densification work hardening behaviour

Dynamics of Entanglement in Qubit-Qutrit with x-Component of DM Interaction

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Communications in Theoretical Physics 2016年第3期65卷 278-284页

作者： kapil k.Sharma S.N.pandey Department of Physics Motilal Nehru National Institute of Technology

In this present paper,we study the entanglement dynamics in qubit A-qutrit B pair under x component of Dzyaloshinshkii-Moriya interaction(D_x)by taking an auxiliary qubit ***,we consider an entangled qubit-qutrit pair initially prepared in two parameter qubit-qutrit states and one auxiliary qubit prepared in pure state interacts with the qutrit of the pair through DM *** trace away the auxiliary qubit and calculate the reduced dynamics in qubit A-qutrit B pair to study the influence of the state of auxiliary qubit C and D_x on *** find that the state(probability amplitude)of auxiliary qubit does not influence the entanglement,only D_x influences the *** phenomenon of entanglement sudden death(ESD)induced by D_x has also been *** also present the affected and unaffected two parameter qubit-qutrit states by D_x.

关键词： entanglement dynamics qubit-qutrit DM interaction ESD