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International Journal of Minerals,Metallurgy and Materials 2016年第6期23卷 658-666页

作者： Ahmad Zare s.r.Hosseini Department of Materials Engineering Maleke-ashtar University of Technology

The influence of soaking time in deep cryogenic treatment on the tensile and impact properties of low-alloy medium-carbon HY-TUF steel was investigated in this study. Microstructural studies based on phase distribution mapping by electron backscatter diffraction show that the deep cryogenic process causes a decrease in the content of retained austenite and an increase in the volume fraction of η-carbide with increasing soaking time up to 48 h. The decrease in the content of retained austenite from ~1.23vol% to 0.48vol% suggests an isothermal martensitic transformation at 77 K. The η-type precipitates formed in deep cryogenic-treated martensite over 48 h have the Hirotsu and Nagakura orientation relation with the martensitic matrix. Furthermore, a high coherency between η-carbide and the martensitic matrix is observed by high-resolution transmission electron microscopy. The variations in macrohardness, yield strength, ultimate tensile strength, and ductility with soaking time in the deep cryogenic process show a peak/plateau trend.

关键词： low alloy steel medium carbon steel cryogenic treatment microstructure mechanical properties fractography

response of a slender cylindrical member under breaking wave impact

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Journal of Hydrodynamics 2019年第2期31卷 345-357页

作者： Manjula r. sannasiraj s.A Department of Civil Engineering National Institute of TechnologyTiruchirappalliIndia Department of Ocean Engineering Indian Institute of Technology MadrasChennaiIndia

A slender cylindrical member is the fundamental component of many coastal and offshore *** is essential to understand the action of breaking waves on structural members since,when these members are subjected to wave impact load,the structural damages and failures may be *** the present study,an experimental investigation has been carried out to measure the response of the slender vertical cylinder subjected to breaking wave *** measurements were made in order to estimate the total force acting on the *** empirical relation is established between total impact force and the wave steepness parameter which dictates the intensity of the *** rise time is an important parameter dictating the impact *** acceleration and strain measurements were made to evaluate the response of the *** has been derived from structure *** deflection due to the moderate plunging differs by two order more than severe plunging *** rate is another important consideration for the impact *** higher strain rate increases the resistance of the *** the breaking wave impact on the cylinder,the strain rate varies from 102 to 10-4.

关键词： Breaking wave impact acceleration slender vertical cylinder wave steepness strain rate strain

Head-on collision between single-and multi-soliton heavy ion acoustic waves in multi-ion plasmas

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Plasma science and Technology 2019年第9期21卷 58-72页

作者： M s ALAM M r TALUKDEr Department of Mathematics Chittagong University of Engineering and Technology Chittagong-4349 Bangladesh Plasma science and Technology Lab Department of Electrical and Electronic Engineering University of Rajshahi Rajshahi-6205 Bangladesh

Head-on collisions among the single-and multi-soliton’s heavy ion acoustic waves(HIAWs) of multi-ion plasma are studied. The plasma consists of adiabatic positively charged inertial heavy ions, Boltzmann energy distributed light ions and kappa energy distributed electrons. The extended poincaré-Lighthill-Kuo(e PLK) method is applied for the derivation of two-sided Korteweg–de Vries(KdV) equations(KdVEs). The KdV single-soliton solutions(KdVsss) are determined using the hyperbolic secant method and the KdV multi-soliton solutions(KdVMss)are obtained using the Hirota method. The effects of superthermality of electrons, temperature ratios of electron to light ion and heavy ion to electron, and the density ratio of electron to heavy ion on phase shifts are investigated for the head-on collisions between two-soliton HIAWs. The effects of plasma parameters on angular frequency, phase speed, production of multi-soliton structures, and the head-on collisions among single-, double-, triple-, quadruple-, and quintuplesolitons are also studied.

关键词： HIAWs multi-soliton kappa-distribution ePLK method Hirotta's method multi-ion

Eigen value analysis of composite hollow shafts using modified EMBT formulation considering the shear deformation along the thickness direction

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Defence Technology（防务技术） 2023年第10期28卷 1-12页

作者： Pavani Udatha A.s.sekhar Velmurugan r Machine Design section Department of Mechanical EngineeringIIT MadrasChennai600036India Department of Aerospace Engineering IIT MadrasChennai600036India

Composite hollow shafts are used in power transmission applications due to their high specific stiffness and high specific *** dynamic characteristics of these shafts are important for transmission *** modelling of these shafts is generally carried out using Equivalent Modulus Beam Theory(EMBT)and Layerwise Beam Theory(LBT)*** EMBT formulation is modified by considering stacking sequence,shear normal coupling,bending twisting coupling and bending stretching *** is observed that modified EMBT formulation is underestimating the shafts stiffness at lower length/mean diameter(l/dm)*** the present work,a new formulation is developed by adding shear deformation along the thickness direction to the existing modified EMBT *** variation of shear deformation along the thickness direction is found using different shear deformation theories,i.e.,first-order shear deformation theory(FsDBT),parabolic shear deformation theory(PsDBT),trigonometric shear deformation theory(TsDBT),and hyperbolic shear deformation theory(HsDBT).The analysis is performed at l/d_(m) ratios of 5,10,15,20,25,30,35,and 40 for carbon/epoxy composites,E-glass/epoxy composites,and boron/epoxy composite *** results show that new formulation has improved the bending natural frequency of the composite shafts for l/d_(m)rison with modified *** effect of new formulation is more significant for the second and third bending modes of natural frequencies.

关键词： Composite hollow shafts Bending natural frequency Modified EMBT formulation Thickness effect

Energy-based damage assessment of continuous-span reinforced concrete highway bridges

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Earthquake Engineering and Engineering Vibration 2023年第1期22卷 191-209页

作者： s.Mahboubi M.r.shiravand Faculty of Civil Water and Environmental EngineeringShahid Beheshti UniversityTehran ***Iran

This paper conducts a comparative study on seismic damage to reinforced concrete(rC)bridges,using three damage models:Park and Ang,Hindi and sexsmith,and input energy-based damage(IEBD)indices,and presents a global cumulative damage model based on the IEBD index to establish a practical damage assessment of an overall bridge system.A series of rC bridges are studied under seismic loadings,and to compare the efficiency and reliability of the damage indices,damage curves of rC piers are developed,and damage levels of piers are calculated at design basis earthquake(DBE)and maximum considered earthquake(MCE)*** global cumulative damage index is calculated for bridge models regarding damage values of *** results indicate that the IEBD index shows a gradual progression of damage and provides reasonable values for different damage levels of piers compared to two other damage ***,the global cumulative damage index shows the impact of induced damage to a certain component regarding the damage level of the overall bridge ***,this new approach is a relatively simple and practical tool for seismic damage assessment of rC bridge systems,which can be implemented in finite element models,particularly in the absence of experimental data.

关键词： rC bridge energy-based damage index global cumulative damage index IEBD Index

MHD flow of a visco-elastic fluid through a porous medium between infinite parallel plates with time dependent suction

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Journal of Hydrodynamics 2015年第5期27卷 738-747页

作者： BAAG s. ACHArYA M.r. DAsH G.C. MIsHrA s.r. Department of Physics College of Basic Science and HumanitiesOUAT Department of Mathematics ITER SOA University

This work provides a comprehensive theoretical analysis of MHD unsteady free convection viscoelastic fluid flow through a porous medium. The medium is treated as incompressible and optically transparent. The flow of the fluid is initiated by shearing action of the moving wall with time dependent suction. radiative heat flow is considered in temperature equation. The coupled nonlinear problem has been solved asymptotically. Approximate solutions have been obtained for the mean velocity, mean temperature using multi parameter perturbation technique. The originality of the present study is to investigate the effect of viscoelastic property of the fluid（Walters B？ model） on the flow and heat transfer phenomena when the flow is permeated through a porous medium with uniform porous matrix subject to transverse magnetic field and time dependent fluctuative suction at the boundary surface. The case of viscous flow has been discussed as a particular case on comparison with the result reported earlier and it is in good agreement. Flow reversal is indicated incase of viscoelastic fluid with high heat capacity in the presence of magnetic field. The higher cooling of the plate in case of viscoelastic flow also causes a flow reversal.

关键词： viscoelastic liquid porosity radiation parameter time dependent suction

synthesis and spectral characterization of lanthanide complexes with 1,2-diphenyl-4-butyl-3,5-pyrazolidinedione: Luminescent property of Tb(Ⅲ) complex

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Journal of rare Earths 2012年第7期30卷 709-715页

作者： M.r.Anoop P.s.Binil s.suma M.r.sudarsanakumar Department of Chemistry S.N. College Department of Chemistry S.N .College Depart-ment of Chemistry M.G. College

The complexes of rare earth elements with 1,2-diphenyl-4-butyl-3,5-Pyrazolidinedione （PBH, phenylbutazone） were synthesized and characterized by elemental analysis, molar conductance, Ir, UV-Vis, EPr and magnetic moment measurements. Based on these studies the complexes were formulated as [Ln（PB）3（H2O）2].nH2O, where Ln=Eu（III）, Gd（III）, Tb（III）, Dy（III） and Er（III）. From Ir spectra, it was found that PBH acted as a bidentate mono-ionic ligand coordinating through two carbonyl oxygen of the pyrazolidinedione ring. The thermal analysis of all the complexes was carried out at a heating rate of 10 oC/min. The kinetic aspects of the complexes were evaluated. The nega-tive entropy value of the complexes indicated a more ordered state for the activated complexes. The photoluminescence property of Tb（III） complex was investigated. It showed all the characteristic emission peaks of Tb^3＋ with a life time of 0.98914 ms.

关键词： lanthanide complexes Ir thermal analysis luminescent properties rare earths

synthesis, spectral characterization, thermal and biological studies of lanthanide(Ⅲ) complexes of oxyphenbutazone

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Journal of rare Earths 2014年第1期32卷 43-51页

作者： P.s.Binil M.r.Anoop K.r.Jisha s.suma M.r.sudarsanakumar Department of Chemistry S.N.College Department of Chemistry M.G.College

Lanthanide（III） complexes of 4-butyl-1-（4-hydroxyphenyl）-2-phenyl-3,5-pyrazolidinedione （OPB） were prepared by ho-mogeneous precipitation. The solid complexes were characterized by elemental analysis, magnetic susceptibility data, molar conduc-tivity measurements and Ir, UV-Vis, mass, 1H NMr and 13C NMr spectral methods. The thermal decomposition of the complexes under static air atmosphere was investigated by simultaneous TG/DTG at a heating rate of 10 °C/min. The final decomposition prod-ucts were found to be metal oxides. The spectroscopic data suggested that OPB acted as a bidentate, mono-ionic ligand coordinating through two carbonyl oxygens of the pyrazolidinedione ring. The kinetic and thermodynamic parameters such as activation energy, pre-exponential factor and entropy of activation for each step of the decomposition reactions were evaluated using Coats-redfern and MacCallum-Tanner equations. The negative entropy values of the complexes indicated that the activated complexes had a more or-dered structure than the reactant and that the reactions were slower than normal. Investigations of antimicrobial activity of the com-pounds were carried out by the disk diffusion technique.

关键词： oxyphenbutazone lanthanide(III) complexes thermal study antimicrobial activity rare earths

New Primers for Denaturing Gradient Gel Electrophoresis Analysis of Nitrate-reducing Bacterial Community in soil

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Pedosphere 2013年第3期23卷 340-349页

作者： r.PAsTOrELLI r.PICCOLO s.sIMONCINI s.LANDI Consiglio per la ricerca e la sperimentazione in Agricoltura-Centro di ricerca per l'Agrobiologia e la Pedologia CRA-ABP

The narG gene is frequently used as a molecular marker for bacterial nitrate-reducing community analysis. In this study, a new set of primers targeting the narG gene was designed and applied to semi-nested polymerase chain reaction-denaturing gradient gel electrophoresis （PCr-DGGE） assay. The potential of the new primers was verified on DNA directly extracted from soils from five different experimental sites distributed in Central and southern Italy. specificity of the primers was determined by excision, amplification, and sequencing of bands resolved by DGGE. A phylogenetic analysis showed the correlation between the sequences retrieved from the soils studied and the narG sequences from βand y-Proteobacteria. These primers expanded the existing molecular tools for ecological study on the size and diversity of nitrate-reducing bacterial community in soil.

关键词： DNA gene sequence narG phylogenetic analysis Proteobacteria

seismic behavior of variable frequency pendulum isolator

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Earthquake Engineering and Engineering Vibration 2008年第2期7卷 193-205页

作者： V. r. Panchal r. s. Jangid Department of Civil Engineering Indian Institute of TechnologyBombayPowaiMumbai 400076India

Earthquake performance of a flexible one-story building isolated with a variable frequency pendulum isolator （VFPI） under near-fault and far-field ground motions is investigated. The frictional forces mobilized at the interface of the VFPI are assumed to be velocity dependent. The interaction between frictional forces of the VFPI in two horizontal directions is duly considered and coupled differential equations of motion of the isolated system in the incremental form are solved iteratively. The response of the system with bi-directional interaction is compared with those without interaction. In addition, the effects of velocity dependence on the response of the isolated system are also investigated. Moreover, a parametric study is carried out to critically examine the influence of important parameters on bi-directional interaction effects of the frictional forces of the VFPI. These parameters are： the superstructure time period, frequency variation factor （FVF） and friction coefficient of the VFPI. From the above investigations, it is observed that the dependence of the friction coefficient on relative velocity of the system does not have a noticeable effect on the peak response of the system isolated with VFPI, and that the bi-directional interaction of frictional forces of the VFPI is important and if neglected, isolator displacements will be underestimated and the superstructure acceleration and base shear will be overestimated.

关键词： base isolation bi-directional interaction superstructure flexibility near-fault ground motion friction coefficient far-field ground motion VFPI