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Influence of Heat Input on Martensite Formation and Impact Property of Ferritic-Austenitic Dissimilar Weld Metals

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Journal of Materials Science & technology 2012年第4期28卷 343-352页

作者： M. Mukherjee t.k. Pal Welding technology Centre Metallurgical and Material Engineering Department Jadavpur University

the effect of heat input on martensite formation and impact properties of gas metal arc welded modified ferritic stainless steel （409M） sheets （as received） with thickness of 4 mm was described in detail in this work. the welded joints were prepared under three heat input conditions, i.e. 0.4, 0.5 and 0.6 kJ/mm using two different austenitic filler wires （308L and 316L） and shielding gas composition of Ar ＋ 5% CO2. the welded joints were evaluated by microstructure and charpy impact toughness. the dependence of weld metal microstructure on heat input and filler wires were determined by dilution calculation, Creq/Nieq ratio, stacking fault energy （SFE）, optical microscopy （OM） and transmission electron microscopy （tEM）. It was observed that the microstructure as well as impact property of weld metal was significantly affected by the heat input and filler wire. Weld metals prepared by high heat input exhibited higher amount of martensite laths and toughness compared with those prepared by medium and low heat inputs, which was true for both the filler wires. Furthermore, 308L weld metals in general provided higher amount of martensite laths and toughness than 316L weld metals.

关键词： Heat input Ferritic-austenitic dissimilar weld Martensite Grain size toughness

Slow-roll inflation in f(t,t)modified gravity

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Chinese Physics C 2023年第12期47卷 162-168页

作者： Aaqid Bhat Sanjay mandal P.k.Sahoo Department of Mathematics Birla Institute of Technology and Science-PilaniHyderabad CampusHyderabad-500078India Faculty of Mathematics and Computer Science Transilvania UniversityIuliu Maniu Str.50500091 BrasovRomania

In this study, we explore the concept of cosmological inflation within the framework of the f(t, t)theory of gravity, where f is a general function of the torsion scalar t and the trace t of the energy-momentum *** is assumed that the conditions of slow-roll inflation are applicable in f(t, t) gravity. to determine different observables related to inflation, such as the tensor-to-scalar ratio r, scalar spectral index ns, spectral index αs, and tensor spectral index nt, the Hubble slow-roll parameters are utilized for a particular model of f(t, t). Lastly, an assessment is carried out to determine the feasibility of the models by conducting a numerical analysis of the parameters. the findings indicate that it is feasible to achieve compatibility with the observational measurements of slow-roll parameters by utilizing different values of the free parameters.

关键词： f(t,t)gravity early-time cosmology dark energy equation of state slow-roll inflation

NONLINEAR COUPLED RESPONSE OF tENSION LEG PLAtFORM

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China Ocean Engineering 1990年第3期5卷 261-272页

作者： Shakib Hamzeh Datta t.k. Research Scholar Civil Engineering Department Indian Institute of Technology New Delhi India Professor Civil Engineering Department Indian Institute of Technology New Delhi India

A dynamic response analysis of tension leg platform (tLP) to deterministic first order wave forces is presented, considering coupling between various degrees of freedom surge, sway, heave, pitch, roll and yaw. the analysis duly considers nonlinearities produced due to changes in cable-tension and due to nonlinear hydro-dynamic drag forces. the wave forces on the elements of the pontoon structure are calculated using Airy's wave theory and Morison's equation. the nonlinear equation of motion is solved in the time domain by Newmark's β-method. With the help of proposed analysis, some example problems are solved in order to investigate the effects of different important factors that influence the response of tLP.

关键词： NONLINEAR COUPLED RESPONSE OF tENSION LEG PLAtFORM

Insights into chondrule formation process and shock-thermal history of the Dergaon chondrite (H4-5)

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Geoscience Frontiers 2017年第3期8卷 413-423页

作者： D. Ray S. Ghosh t.k. Goswami M.J. Jobin PLANEX Physical Research Laboratory Ahmedabad 380 009 India Department of Applied Geology Dibrugarh University Assam India Department of Applied Geology Pondicherry University India

the Dergaon fall represents a shock-melted H4-5 （S5） ordinary chondrite which includes at least ten textural varieties of chondrules and belongs to the high chondrule-matrix ratio type. Our study reveals that the chondrules are of diverse mineralogy with variable olivine-pyroxene ratios （type Ⅱ）, igneous melt textures developed under variable cooling rates and formed through melt fractionations from two different melt reservoirs. Based on the experimental analogues, mineralogical associations and phase compositions, it is suggested that the Dergaon chondrules reflect two contrasting environments： a hot, dust-enriched and highly oxidized nebular environment through melting, without significant evapora- tion, and an arrested reducing environment concomitant with major evaporation loss of alkali and highly volatile trace elements. Coexistence of chlorapatite and merrillite suggests formation of the Dergaon matrix in an acidic accretionary environment. textural integration and chemical homogenization occurred at - I atmospheric pressure and a mean temperature of 765 ℃ mark the radiogenic thermal event. Equilibrated shock features （olivine mosaicism, diaplectic plagioclase, polycrystalline troilite） due to an impact-induced thermal event reflect a shock pressure 〉45 GPa and temperature of 600 ℃. By contrast, the local disequilibrium shock features （silicate melt veins comprising of olivine crystallites, troilite melt veins and metal droplets） correspond to a shock pressure up to 75 GPa and temperature 〉950 ℃.

关键词： Dergaon chondrite Chondrule thermal metamorphism Shock metamorphism

Analysis of a fractional-order SIS epidemic model with saturated treatment

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International Journal of Modeling, Simulation, and Scientific Computing 2021年第1期12卷 185-212页

作者： Soovoojeet Jana Manotosh mandal Swapan kumar Nandi t.k.kar Department of Mathematics Ramsaday College Amta-711401HowrahWest BengalIndia Department of Mathematics Tamralipta Mahavidyalaya Tamluk-721636West BengalIndia Department of Mathematics Nayabasat P.M.Sikshaniketan Paschim Medinipur-721253West BengalIndia Department of Mathematics Indian Institute of Engineering Science and technology Shibpur Howrah-711103West BengalIndia

In this paper,we propose and analyze a fractional-order SIS epidemic model with the saturated treatment and disease *** existence and uniqueness,nonnegativity and finiteness of solutions for our suggested model have been *** equilibria of the model are found and their local and global stability analyses are also ***,the conditions for fractional backward and fractional Hopf bifurcation are also analyzed in both the commensurate and incommensurate fractional-order *** study how the control parameter and the order of the fractional derivative play role in local as well as global stability of equilibrium points and Hopf *** have demonstrated the analytical results of our proposed model system through several numerical simulations.

关键词： Caputo fractional differentiation SIS epidemic model global asymptotic stability treatment control fractional Hopf bifurcation fractional backward bifurcation

Content sensitivity based access control framework for Hadoop

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Digital Communications and Networks 2017年第4期3卷 213-225页

作者： Ashwin kumar t.k. Hong Liu Johnson P. thomas Xiaofeh Hou Department of Computer Science Oklahoma State University Stillwater OK USA

Big data technologies have seen tremendous growth in recent years. they are widely used in both industry and academia. In spite of such exponential growth, these technologies lack adequate measures to protect data from misnse/abuse. Corporations that collect data from multiple sources are at risk of liabilities due to the exposure of sensitive information. In the current implementation of Hadoop, only file-level access control is feasible. Providing users with the ability to access data based on the attlibutes in a dataset or the user＇s role is complicated because of the sheer volume and multiple formats （structured, unstructured and semi-structured） of data. In this paper, we propose an access control framework, which enforces access control policies dynamically based on the sensitivity of the data. this framework enforces access control policies by harnessing the data context, usage patterns and informat/on sensitivity. Information sensitivity changes over time with the addition and removal of datasets, which can lead to modifications in access control decisions. the proposed framework accommodates these changes. the proposed framework is automated to a large extent as the data itself determines the sensitivity with minimal user intervention. Our experimental results show that the proposed framework is capable of enforcing access control policies on non-multimedia datasets with minimal overhead.

关键词： Access control Data driven information sensitivity Privacy Information value

theoretical study of differential cross sections for the ionization of helium by fast proton impact

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Chinese Physics B 2024年第11期33卷 255-264页

作者： M Mondal B mandal t Mistry D Jana M Purkait Department of Physics Ramakrishna Mission Residential CollegeNarendrapurKolkata-700103India

We present the angular distribution of the ejected electron for single ionization of He by fast proton impact.A fourbody formalism of the three-Coulomb wave is applied to calculate the triple differential cross sections at several impact energies in the scattering,perpendicular and azimuthal ***,the three-body formalism of three-Coulomb,two-Coulomb and first Born approximation models has also been used to study the many-body effect on electron emission and the validity of the *** the three-Coulomb wave model,the final state wave function incorporates distortion due to the three-body mutual Coulombic *** this formalism,we use an uncorrelated and correlated Born initial state,which consists of a plane wave for the incoming projectile times a two-electron bound state wavefunction of the helium atom representing the 1s2(1S)***,in the case of the three-body formalism,the initial state wavefunction consists of a long-range Coulomb distortion for the incoming projectile and one active electron of the He atom described by the Roothaan–Hartree–Fock *** structure with a single or two peaks with unequal intensity is observed in the angular distributions of the triple differential cross sections for the different.k.nematic *** addition,the influence of static electron correlations is investigated using different bound state wavefunctions for the ground state of the He *** the four-body formalism,the present computations are very fast by reducing a nine-dimensional integral to a two-dimensional real *** the simplicity and speed of the proposed quadrature,the comparison shows that the obtained results are in reasonable agreement with the experiment and are compatible with those of other theories.

关键词： ionization cross sections collision atoms ions

Seasonal variability of ambient NH_3, NO, NO_2 and SO_2 over Delhi

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Journal of Environmental Sciences 2010年第7期22卷 1023-1028页

作者： S.k.Sharma A.Datta t.Saud M.Saxena t.k.mandal Y.N.Ahammed B.C.Arya Radio and Atmospheric Sciences Division National Physical Laboratory Council of Scientific and Industrial Research (CSIR)

We present the diurnal and seasonal variability of ambient NH3, NO, NO2 and SO2 over Delhi, India. Ambient NH3, NO and NO2 were measured continuously during winter, summer and autumn seasons using NH3- and NOx-analyzer, which operates by chemiluminescence method with a higher estimation efficiency （〉 90%） than the chemical trap method （reproducibility 4.7%）. Prominent diurnal, day-to-day and seasonal variations of ambient mixing ratio of NH3, NO, NO2 and SO2 were observed during the study period. Seasonal variation with higher mixing ratio in winter was observed for all measured trace gases except NO. Day-night variation of all measured trace gases observed was higher in winter in comparison with summer. Late morning increase in NO2 mixing ratio might be attributed to conversion of NO to NO2 with the interaction ofO3.

关键词： ambient NH3, diurnal and seasonal variations chemiluminescence method ambient NO, NO2 and SO2

Upper mantle anisotropy inferred from shear wave splitting beneath the Eastern Indian Shield region

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Geoscience Frontiers 2018年第6期9卷 1911-1920页

作者： kuntal Bhukta Prosanta k.khan Prant.k.mandal Indian Institute of technology(Indian School of Mines) DhanbadIndia National Geophysical Research Institute HyderabadIndia

We estimate the shear wave splitting parameters vis-a-vis the thicknesses of the continental lithosphere beneath the two permanent seismic broadband stations located at Dhanbad(DHN) and Bokaro(BOkR) in the Eastern Indian Shield region. Broadband seismic data of 146 and 131 teleseismic earthquake events recorded at DHN and BOkR stations during 2007-2014 were analyzed for the present *** study is carried out using rotation-correlation and transverse component minimization methods. We retain our "Good", "Fair" and "Null" measurements, and estimate the splitting parameters using 13 "Good" results for DHN and 10 "Good" results for BOkR stations. the average splitting parameters(φ,δt)for DHN and BOkR stations are found to be 50.76°±5.46° and 0.82±0.2 s and 56.30°±5.07° and0.95 ± 0.17 s, and the estimated average thicknesses of the anisotropic layers beneath these two stations are ～94 and ～109 km,respectively. the measured deviation of azimuth of the fast axis direction(0)from the absolute motion of the Indian plate ranges from ～8° to 14°. the measured deviation of azimuth of the fast axis direction(0) from the absolute motion of the Indian plate ranges from ～8° to 14°. the eastward deviation of the fast axis azimuths from absolute plate motion direction is interpreted to be caused by induced outflow from the asthenosphere. Further, the delay time found in the present analysis is close to the global average for continental shield areas, and also coherent with other studies for Indian shield regions. the five "Null" results and the lower delay time of ～0.5-0.6 s might be indicating multilayer anisotropy existing in the mantle lithosphere beneath the study area.

关键词： Eastern Indian shield Seismic anisotropy Splitting parameters Absolute plate motion