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Acta Metallurgica Sinica(English Letters) 2023年第7期36卷 1078-1094页

作者： Tuhin das Salim v.Brahimi Jun Song Stephen Yue Department of Materials Engineering McGill UniversityMontrealQC H3A OC5Canada Industrial Fasteners Institute ClevelandOH 44131USA

A newly proposed rapid fracture test in four-point bending was used to evaluate the effect of tempering on the hydrogen embrittlement(HE)susceptibility of an AISI 4135 steel,where it was tempered to four different strength(or hardness)*** was observed that HE susceptibility increases with the increase in *** was shown that there will be minimal impact of hydrogen(H)on the fracture of materials with hardness 37 HRC and below,even if they are completely saturated with *** the other hand,H will have similar detrimental effect on fracture properties of quench and tempered(Q and T)steels having hardness higher than 45 *** to brittle transition behavior was observed for a critical hardness(or strength)range as well as for a critical concentration level of ***,a critical H concentration was observed to exist for each of the strength *** was performed in addition to microstructural characterization using transmission electron microscopy(TEM).A very good correlation was observed between the fast fracture test results and *** fast fracture test was further compared with a conventional incremental step load(ISL)test for the evaluation of HE *** ISL test results and fracture surface characteristics corroborate very well with the observations from the fast fracture *** study successfully establishes the fast fracture test as a novel technique to study HE susceptibility and mechanism(s).

关键词： Hydrogen embrittlement(HE) Mechanical testing Fracture mechanics Martensitic steel Hardness Dislocation density

Analysis of interrelationship between pedestrian flow parameters using artificial neural network

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Journal of Modern Transportation 2015年第4期23卷 298-309页

作者： Pritikana das M.Parida v.K.Katiyar Centre for Transportation Systems Indian Institute of Technology Roorkee Department of Civil Engineering Transportation Engineering Group Indian Institute of Technology Roorkee Department of Mathematics Indian Institute of Technology Roorkee

Pedestrian flow parameters are analysed in this study considering linear and non-linear relationships between stream flow parameters using conventional and soft computing approach. Speed-density relationship serves as a fundamental relationship, Single-regime con- cepts and deterministic models like Greenshield and Underwood were applied in the study to describe bidirec- tional flow characteristics on sidewalks and carriageways around transport terminals in India. Artificial Neural Net- work （ANN） approach is also used for traffic flow mod- elling to build a relationship between different pedestrian flow parameters. A non-linear model based on ANN is suggested and compared with the other deterministic models. Out of the aforesaid models, ANN model demonstrated good results based on accuracy measure- ment. Also these ANN models have an advantage in terms of their self-processing and intelligent behaviour. Flow parameters are estimated by ANN model using MFD （Macroscopic Fundamental Diagram）. Estimated mean absolute error （MAE） and root mean square error （RMSE）values for the best fitted ANN model are 3.83 and 4.73 m/ min, respectively, less than those for the other models for sidewalk movement. Further estimated MAE and RMSE values of ANN model for carriageway movement are 4.02 and 4.98 m/min, respectively, which are comparatively less than those of the other models. ANN model gives better performance in fitness of model and future prediction of flow parameters. Also when using linear regression model between observed and estimated values for speed and flow parameters, performance of ANN model gives better fitness to predict data as compared to deterministic model. R value for speed data prediction is 0.756 and for flow data pre- diction is 0.997 using ANN model at sidewalk movement around transport terminal.

关键词： ANN Pedestrian flow modelling Macroscopic flow diagram MAE RMSE

DEFICIENT CUBIC SPLINES WITH AvERAGE SLOPE MATCHING

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Analysis in Theory and Applications 2005年第1期21卷 1-14页

作者： v.B.das A.Kumar R.D.University India R.D.University India

We obtain a deficient cubic spline function which matches the functions with certain area matching oner a greater mesh intervals, and also provides a greater flexibility in replacing area matching as interpolation. We... 详细信息

关键词： deficient cubic splines area slope interpolation

Optical Emission Spectroscopic Study During the Evaporation of Aluminium in the Thermal Plasma Reactor

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Plasma Science and Technology 2010年第1期12卷 27-30页

作者： I.BANERJEE N.v.KULKARNI S.KARMAKER v.L.MATHE S.v.BHORASKAR A.K.das Applied Physics Department Birla Institute of Technology Department of Physics University of Pune Department Bhabha Atomic Research Center

The oxidation of aluminium was studied using optical emission spectroscopy （OES） during the evaporation of aluminium in traces of oxygen in a thermal plasma reactor. The ratio of the measured line intensities of Al-O with that of Al follows the exact trend as of that obtained from the corresponding line intensities in X-ray diffraction spectra of the synthesized samples. In this paper the inherent capacity of emission spectroscopy in evaluating the growth processes under plasma induced reactions is presented.

关键词： thermal plasma reactor aluminium oxidation optical emission spectroscopy,X-ray diffraction

Detection of canine echinococcosis by coproantigen ELISA

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Asian Pacific Journal of Tropical Medicine 2010年第7期3卷 519-522页

作者： De S Pan D Bera AK Sreevatsava v das SK das S Rana T Bandyopadhyay S Bhattacharya D Indian veterinary Research Institute Eastern Regional Station37 Belgachia Road.Kolkata-700037India NRC on Yak DirangArunachal PradeshIndia Indian veterinary Research Institute.Eastern Regional Station.37 Belgachia Road Kolkata-700037India

Objective:To study the canine echinococcosis by coproantigen ELISA ***:During the present investigation experimental infection was established using evaginated worms of Echinococcus granulosus(***).To check cross reactivity two pups were infected with Taenia hydatigena(***).In order to detect the presence of antigen,hyperimmune sera were raised against excretory-secretory products of adult worms *** granulosus. Faecal sample collected either from experimentally infected pups or from other sources were heated at 70℃to detect heat stable soluble ***:Pups harbouring less than 104 worms showed negative *** collected from 14 days onwards from experimentally infected animals harbouring more than 104 worms showed positive *** maximum positive samples were detected in samples collected from in and around slaughter house and the least number of samples were detected positive maintained by dog ***:The affinity purified IgG exhibited promising results for detection of canine echinococcosis by indirect ELISA.

关键词： Echinococcus granulosus Coproantigen ELISA Canine

Design and Implementation of Digital Fractional Order PID Controller Using Optimal Pole-Zero Approximation Method for Magnetic Levitation System

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IEEE/CAA Journal of Automatica Sinica 2018年第5期5卷 977-989页

作者： Amit S.Chopade Swapnil W.Khubalkar A.S.Junghare M.v.Aware Shantanu das IEEE the Department of Electrical Engineering Visvesvaraya National Institute of TechnologyNagpur India-440010India Reactor Control Division Bhabha Atomic Research CentreIndia

The aim of this paper is to employ fractional order proportional integral derivative(FO-PID)controller and integer order PID controller to control the position of the levitated object in a magnetic levitation system(MLS),which is inherently nonlinear and unstable *** proposal is to deploy discrete optimal pole-zero approximation method for realization of digital fractional order *** approach of phase shaping by slope cancellation of asymptotic phase plots for zeros and poles within given bandwidth is *** controller parameters are tuned using dynamic particle swarm optimization(d PSO)*** of the proposed control scheme is verified by simulation and experimental *** performance of realized digital FO-PID controller has been compared with that of the integer order PID *** is observed that effort required in fractional order control is smaller as compared with its integer counterpart for obtaining the same system performance.

关键词： Approximation methods digital control dis-cretization fractional calculus fractional order PID controller(FO-PID) magnetic levitation particle swarm optimization(PSO) position control.

Active learning of deep surrogates for PDEs:application to metasurface design

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npj Computational Materials 2020年第1期6卷 312-318页

作者： Raphaël Pestourie Youssef Mroueh Thanh v.Nguyen Payel das Steven G.Johnson Department of Mathematics Massachusetts Institute of Technology77 Massachusetts AveCambridgeMA 02139USA IBM Research AI IBM Thomas J Watson Research CenterYorktown HeightsYorktownNY 10598USA MIT-IBM Watson AI Lab CambridgeMA 02139USA Iowa State University AmesIA 50011USA

Surrogate models for partial differential equations are widely used in the design of metamaterials to rapidly evaluate the behavior of composable ***,the training cost of accurate surrogates by machine learning can rapidly increase with the number of *** photonic-device models,we find that this training becomes especially challenging as design regions grow larger than the optical *** present an active-learning algorithm that reduces the number of simulations required by more than an order of magnitude for an NN surrogate model of optical-surface components compared to uniform random *** show that the surrogate evaluation is over two orders of magnitude faster than a direct solve,and we demonstrate how this can be exploited to accelerate large-scale engineering optimization.

关键词： optimization surrogate faster

visible Light Excitable SCN^- Selective Fluorescence Probe Derived from Thiophene

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Chinese Journal of Chemistry 2015年第10期33卷 1173-1177页

作者： Sudipta das Sisir Lohar Jesus Sanmartin Matalobos Debasis das Department of Chemistry The University of Burdwan Burdwan 713104 West Bengal India Departamento de Qu'tmicalnorg'anica Facultade de Qutmica Avda. Das Ciencias s/n 15782 Santiago de Compostela Spain

An efficient fluorescence probe, 4-methyl-2,6-bis（（thiophen-2-ylmethylimino）methyl）phenol （DFPTMA） and its SCN adduct has been synthesized and characterized by different spectroscopic techniques like ^1H NMR,^13C NMR, QTOF-MS ES^＋, Uv-vis and FTIR spectroscopy. Single crystal X-ray structure of DFPTMA is reported. In presence of SCN-, DFPTMA exhibits significant fluorescence enhancement （λEx, 455 nm, λEm, 504 nm） in aqueous methanol （water-methanol, 1 ： 4, v/v, 0.1 mol/L HEPES buffer, pH 7.4）. Common bio-relevant anions viz. CH3COO^-, NO2, NO7, Cl^-, Br^-, I^-, SO4^2-, HSO4^-, N3^-, HAsO4^2-, Cr2O7^2-, H2PO4, ClO4^-, NCO^-, CN^-, CO3^2-, F^-, PO4^3-, S2-, HS- do not interfere in the recognition of SCN-. Lowest detection limit for SCN^- is 0.88 μmol/L with response time 〈5 min. The SCN assisted enhancement in emission intensity may be attributed to the formation of H-bond which enhances the rigidity of the molecular assembly.

关键词： visible light excitation SCN^- fluorescence thiophene derivative

Study of Tachyon Warm Intermediate and Logamediate Inflationary Universe from Loop Quantum Cosmological Perspective

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Communications in Theoretical Physics 2016年第8期65卷 256-262页

作者： Jyotirmay das Mandal Ujjal Debnath Department of Mathematics Indian Institute of Engineering Science and Technology

We have studied the tachyon intermediate and logamediate warm inflation in loop quantum cosmological background by taking the dissipative co-efficient Γ = Γ_0(where Γ_0 is a constant) in "intermediate" inflation and Γ = v(φ),(where v(φ) is the potential of tachyonic field) in "logamediate" inflation. We have assumed slow-roll condition to construct scalar field φ, potential v, N-folds, etc. various slow-roll parameters have also been *** have analyzed the stability of this model through graphical representations.

关键词： tachyonic field loop quantum cosmological warm inflation

Fabrication of cost effective iron ore slime ceramic membrane for the recovery of organic solvent used in coke production

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International Journal of Coal Science & Technology 2016年第2期3卷 226-234页

作者： v. Singh N. K. Meena A. K. Golder C. das Department of Chemical Engineering Indian Institute ofTechnology Guwahati Guwahati Assam 781039 India

Improvement of coking properties of sub-bituminous coal （A） and bituminous coal （B） was done using blended organic solvents, namely, n-methyl-2-pyrrolidinone （NMP） and ethylenediamine （EDA）. various solvent blends were employed for the coal extraction under the total reflux condition. A low-cost ceramic membrane was fabricated using industrial waste iron ore slime of M/s TATA steel R＆D, Jamshedpur （India） to separate out the dissolved coking fraction from the solvent-coal mixture. Membrane separations were carried out in a batch cell, and around 75 % recovered NMP was reused. The fractionated coal properties were determined using proximate and ultimate analyses. In the case of bituminous coal, the ash and sulfur contents were decreased by 99.3 % and 79.2 %, respectively, whereas, the carbon content was increased by 23.9 % in the separated coal fraction. Three different cleaning agents, namely deionized water, sodium dodecyl sulphate and NMP were used to regain the original membrane permeability for the reusing.

关键词： Iron ore slime Solvent recovery Proximate analysis Ultimate analysis Membrane cleaning