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Identification and modelling of applicable wear conditions for stir cast Al-composite

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Friction 2020年第5期8卷 847-873页

作者： santanu SARDAR santanu Kumar KARMAKAR Debdulal DAS Department of Mechanical Engineering Indian Institute of Engineering Science and TechnologyHowrah 711103India Department of Metallurgy and Materials Engineering Indian Institute of Engineering Science and TechnologyHowrah 711103India

A comprehensive study of the tribological performance of the Al-Zn-Mg-Cu/Al2O3 composite and its matrix alloy is presented in this paper, with a specific emphasis to identify and model the applicable wear conditions where the composite provides a minimum of 50% reduction in wear rate and 25% lowering of the friction coefficient. Two-body abrasion experiments following Taguchi L27 orthogonal design have been performed separately on alloy and composite materials, both prepared by the stir casting method. The influence of crucial control factors including silicon carbide (SiC) abrasive size, load, sliding distance, and velocity on the percentage variations of wear rates and friction coefficients between alloy and composite have been studied using the analysis of variance technique and full quadratic regression method. The dominant control factors are identified as abrasive size, load, and the interaction between abrasive size and load. This has been verified by establishing the influence of abrasive size and load on variations of wear mechanisms like microcutting, microploughing, and delamination, identified by means of in-depth characterization of worn surfaces and generated debris for both alloy and composite. The selection of applicable tribological condition for the composite has been accomplished by adopting the multi-response optimization technique based on combined desirability approach to obtain concurrent optimization of the percentage variations of wear rates and friction coefficients. Predictive models correlating the superiority of tribological performance of composite with abrasion conditions have been developed, and these are found to be accurate (errors <10%), as determined by confirmatory experiment.

关键词： aluminum matrix composite tribology design of experiment Taguchi multi-response optimization abrasion mechanism

Novel Hydrodynamic Analysis Towards Capabilities Improvement of Bio-inspired Underwater Vehicles Using Momentum Redistribution Method

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Journal of Bionic Engineering 2022年第2期19卷 314-330页

作者： Rakesh Rayapureddi santanu Mitra Mechanical Engineering Department Shiv Nadar UniversityDelhi-NCR 201314NoidaIndia

This paper presents an efficient and versatile OpenFOAM(Open-source Field Operation And Manipulation)-based numerical solver for fully resolved simulations that can handle any rigid and deforming bodies moving in the *** algorithm used for solving Fluid-Structure Interactions(FSI)involving the immersed structure with changeable shapes is based on the momentum redistribution *** present approach excludes the need to solve elastic equations,obtain high-accuracy predictions of the flow field and provide a rigorous basis for implementing the Immersed Boundary Method(IBM).The OpenFOAM implementation of the algorithm is discussed along with the design methodology for developing bio-inspired underwater vehicles using the present *** computational results are validated with the experimental observations of the two-dimensional and three-dimensional anguilliform swimmer case *** study further extended to the three-dimensional hydrodynamics of a bioinspired,self-propelling manta *** motion of the body is specified a priori according to the reported experimental *** results quantify the vortex formation and shedding processes and enable the identification of the portions of the body responsible for the majority of *** body accelerates from rest to an asymptotic mean forward velocity of 0.2 ms^(-1)in almost 5 s,consistent with experimental *** is observed that the developed computational model is capable of performing any motion simulation and manoeuvrability analysis,which are critical for the designers to develop novel unmanned underwater vehicles.

关键词： Momentum redistribution method OpenFOAM Fluid-Structure Interaction(FSI) Immersed Boundary Method(IBM) Anguilliform swimming Manta bot

Realizing unipolar and bipolar intrinsic skyrmions in MXenes from high-fidelity first-principles calculations

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npj Computational Materials 2023年第1期9卷 553-564页

作者： Arnab Kabiraj santanu Mahapatra Nano-Scale Device Research Laboratory Department of Electronic Systems EngineeringIndian Institute of Science(IISc)BangaloreBengaluru 560012India

Magnetic skyrmions,which are topologically protected tiny spin textures,have emerged as information carriers in energy-efficient logic and memory *** are commonly realized by inducing large Dzyaloshinskii–Moriya interaction(DMI)in the interface of heavy metal *** the advent of two-dimensional magnetism,it is being envisioned to host intrinsic skyrmions in a monolayer,which will be free from any interfacial defect and stacking *** using high-fidelity exchange-correlation functional-based first-principles calculations,we investigate such a possibility in methodically designed non-centrosymmetric MXene *** a search space of about 3000 materials,our customized high-throughput computational pipeline systematically harnesses out-of-the-plane and in-plane magnetism along with strong DMI to realize typical‘unipolar’skyrmions in 78 materials and exotic‘bipolar’skyrmions in 13 *** and atomistic Monte Carlo simulations further reveal that skyrmions in some of these materials may be stable at room temperature without any external magnetic *** study may pave the way for the practical realization of skyrmions-based information technology.

关键词： field intrinsic principles

Position Control of a Flexible Manipulator Using a New Nonlinear Self-Tuning PID Controller

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IEEE/CAA Journal of Automatica Sinica 2020年第1期7卷 136-149页

作者： santanu Kumar Pradhan Bidyadhar Subudhi School of Electrical Sciences National Institute of Science and Technology BerhampurOdisha 761008India School of Electrical Sciences Indian Institute of TechnologyFarmagudiGoa 403401India

In this paper, a new nonlinear self-tuning PID controller(NSPIDC) is proposed to control the joint position and link deflection of a flexible-link manipulator(FLM) while it is subjected to carry different payloads. Since, payload is a critical parameter of the FLM whose variation greatly influences the controller performance. The proposed controller guarantees stability under change in payload by attenuating the non-modeled higher order dynamics using a new nonlinear autoregressive moving average with exogenous-input(NARMAX) model of the FLM. The parameters of the FLM are identified on-line using recursive least square(RLS) algorithm and using minimum variance control(MVC) laws the control parameters are updated in real-time. This proposed NSPID controller has been implemented in real-time on an experimental set-up. The joint tracking and link deflection performances of the proposed adaptive controller are compared with that of a popular direct adaptive controller(DAC). From the obtained results, it is confirmed that the proposed controller exhibits improved performance over the DAC both in terms of accurate position tracking and quick damping of link deflections when subjected to variable payloads.

关键词： Flexible-link manipulator position control self-tuning control NARMAX trajectory tracking

On Universality of Quantum Fourier Transform

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Chinese Physics Letters 2012年第3期29卷 17-20页

作者： Arpita Maitra santanu Sarkar Applied Statistics Unit Indian Statistical Institute203 B T RoadKolkata 700108India

A methodology is presented to obtain the basis of qudits which are admissible to quantum Fourier transform(QFT)in the sense that the set of such kets are related by the QFT in the same way as the kets of the computational *** first study this method for qubits to characterize the ensemble that works for the Hadamard transformation(QFT for two dimension).In this regard we identify certain incompleteness in the result of Maitra and Parashar(*** Inform.4(2006)653).Next we characterize the ensemble of qutrits for which QFT is ***,some theoretical results related to higher dimensions are also *** the unitary matrix Un related to QFT,the issue boils down to the problem of characterizing matrices that commute with Un.

关键词： ensemble admissible dimensions

High-throughput design of functional-engineered MXene transistors with low-resistive contacts

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npj Computational Materials 2022年第1期8卷 1917-1929页

作者： Sirsha Guha Arnab Kabiraj santanu Mahapatra Nano-Scale Device Research Laboratory Department of Electronic Systems EngineeringIndian Institute of Science(IISc)BangaloreBangalore560012India

Two-dimensional material-based transistors are being extensively investigated for CMOS(complementary metal oxide semiconductor)technology extension;nevertheless,downscaling appears to be challenging owing to high metal-semiconductor contact ***,we propose a functional group-engineered monolayer transistor architecture that takes advantage of MXenes’natural material chemistry to offer low-resistive *** design an automated,high-throughput computational pipeline that first performs hybrid density functional theory-based calculations to find 16 sets of complementary transistor configurations by screening more than 23,000 materials from an MXene database and then conducts self-consistent quantum transport calculations to simulate their current-voltage characteristics for channel lengths ranging from 10 nm to 3 *** of these devices has been found to meet the requirements of the international roadmap for devices and systems(IRDS)for several benchmark metrics(on current,power dissipation,delay,and subthreshold swing).The proposed balanced-mode,functional-engineered MXene transistors may lead to a realistic solution for the sub-decananometer technology scaling by enabling doping-free intrinsically low contact resistance.

关键词： functional complementary doping

Circum-Indian Holocene sea-level database:A repository of distinct relative sea-level plots across the Indian Peninsula

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Journal of Palaeogeography 2024年第1期13卷 1-17页

作者： Shradha Menon Pankaj Khanna santanu Banerjee REEFS Lab Department of Earth SciencesIIT GandhinagarPalajGandhinagarGujarat382355India Department of Earth Sciences IIT BombayPowaiMumbai400076India

The Indian Peninsula is one of the most well-studied regions for Holocene sea-level fluctuations in the world, however, standardized relative sea-level datasets are missing. This study provides an archive of sealevel indicators(n = 162, 20 locations) along the western and the eastern sides of the peninsula, that have been used to develop Relative Sea Level(RSL) plots. Each dated sea-level indicator is recalibrated for its elevation based on tidal and tectonic correction, as well as age with reservoir correction, and have been separated into six zones based on coastal geomorphology and number of datasets. The database spans throughout the Holocene and covers sea-level depth/elevations from-45 m to +5 m from mean sea-level(MSL). Approximately 90 % of the dataset range from 8 ka to the present day. The first transgression is highly variable and identified between 8.5-8 ka BP in Gujarat(Zone 1), ~ 5.5 ka BP in Maharashtra(Zone 2), between 8 and 7 ka BP in Tamil Nadu(Zone 4) and between 8 and 7.5 ka BP in the Bengal coasts(Zone 6). No transgression above present sea-level is observed along Andhra Pradesh(Zone 5)(no data for Kerala-Zone 3).Further, Zones 1, 2, 4 and 6 show a strong uplift component(tectonic), whereas Zone 5 exhibits subsidence during the Holocene(Zone 3-insufficient data). Based on these findings, and given the region's coastal topography and tidal components, Zones 6 and 1 will likely undergo the largest coastal inundation, followed by Zones 5, 4, 2, and 3. These insights are critical in planning future coastal inundation measures across the Indian Peninsula.

关键词： Indian ocean Terraces Relative sea level curve Holocene Arabian sea Bay of Bengal

Inter-relationship between approximate dynamic inversion and MRAC augmented with proportional-integral controller

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Journal of Control and Decision 2023年第3期10卷 348-354页

作者： santanu Mallick Ujjwal Mondal Department of Applied Electronics and Instrumentation Engineering Bankura Unnayani Institute of EngineeringBankuraIndia Instrumentation Engineering Department of Applied PhysicsUniversity of CalcuttaKolkataIndia

Approximate Dynamic Inversion (ADI) is basically an approximation of exact dynamic inversionor feedback linearisation, which converts a nonlinear system to an equivalent linear *** method can be widely applied for controlling minimum phase, nonaffine-in-control *** applying the ADI method, a fast dynamic subsystem for deriving explicit inversion of thenonaffine equation is required. With full state feedback, ADI may be expressed in the same way asa Proportional Integral (PI) controller with only knowledge of the sign of control effectiveness andalso without any approximation. The Model Reference Adaptive Controller (MRAC) augmentedwith the PI method is an adaptive control technique where the PI parameters are updated/tunedas per the control methodology based on the MRAC-Massachusetts Institute of Technology (MIT)rule so that the plant is capable to follow the reference model. The main objective of this paperis to find the relationship between ADI and MRAC augmented with a PI controller.

关键词： Adaptive control approximate dynamic inversion(ADI) feedback linearisation Massachusetts Institute of Technology(MIT)rule model reference adaptive controller(MRAC) proportional-integral(PI)controller

High-throughput discovery of high Curie point two-dimensional ferromagnetic materials

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npj Computational Materials 2020年第1期6卷 1381-1389页

作者： Arnab Kabiraj Mayank Kumar santanu Mahapatra Nano-Scale Device Research Laboratory Department of Electronic Systems EngineeringIndian Institute of Science(IISc)BangaloreBangalore 560012India

Databases for two-dimensional materials host numerous ferromagnetic materials without the vital information of Curie temperature since its calculation involves a manually intensive complex *** this work,we develop a fully automated,hardwareaccelerated,dynamic-translation based computer code,which performs first principles-based computations followed by Heisenberg model-based Monte Carlo simulations to estimate the Curie temperature from the crystal *** employ this code to conduct a high-throughput scan of 786 materials from a database to discover 26 materials with a Curie point beyond 400 *** rapid data mining,we further use these results to develop an end-to-end machine learning model with generalized chemical features through an exhaustive search of the model space as well as the *** discover a few more high Curie point materials from different sources using this data-driven *** material informatics,which agrees well with recent experiments,is expected to foster practical applications of two-dimensional magnetism.

关键词： structure process ferromagnetic