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A study of spot Welding of Advanced High strength steels for Automotive Applications

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Journal of Iron and steel Research International 2011年第S1期18卷 724-729页

作者： Bhole s.d Khan M.s department of Mechanical and Industrial Engineering Ryerson University350 Victoria StreetTorontoONM5B 2K3Canada

The application of advanced high strength steels in automotive industry has highlighted the need for research into spot weldability of these *** weld lobe diagrams,the spot weldability of dP600 steel was found to be poor with conventional weld *** enhanced weld schedule consisting of two pulses with reduced current on the second pulse gave a substantial increase in the lobe width;the first pulse removed the zinc coating and the second pulse controlled the nugget growth.A data acquisition system was.designed to monitor weld expulsion during the weld *** the three possible control strategies propos.d,especially with AC welding equipment,the dynamic resistance signal is easily obtained and the least *** phenomena,microstructural characterization and mechanical properties of spot-welded hot dipped galvanized dP600 steel and interstitial free steel were *** work on dissimilar welds in dP 600 and HsLA 350 was also conducted with emphasis on tensile and fatigue properties and fracture *** performance of dissimilar spot welds was.different from that of the similar spot welds in each of the HsLA350 and dP600 *** dP600 weld properties played a dominating role in the hardness and tensile properties of the dissimilar spot ***,the fatigue performance of the dissimilar welds was similar to that of the HsLA *** will be presented at the conference.

关键词： resistance spot welding dynamic resistance nugget diameter and hardness dissimilar materials microstructure mechanical properties fatigue fracture mode

A comprehensive investigation on nonlinear vibration and bending characteristics of bio-inspired helicoidal laminated composite structures

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 81-100页

作者： s.sAURABH R.KIRAN d.sINGH R.VAIsH V.s.CHAUHAN school of Mechanical and Materials Engineering Indian Institute of Technology Mandi

Bio-inspired helicoidal composite laminates, inspired by the intricate helical structures found in nature, present a promising frontier for enhancing the mechanical properties of structural designs. Hence, this study provides a comprehensive investigation into the nonlinear free vibration and nonlinear bending behavior of bio-inspired composite plates. The inverse hyperbolic shear deformation theory(IHsdT) of plates is employed to characterize the displacement field, with the incorporation of Green-Lagrange nonlinearity. The problem is modeled using the C0finite element method(FEM), and an in-house code is.developed in the MATLAB environment to solve it numerically. Various helicoidal layup configurations including helicoidal recursive(HR), helicoidal exponential(HE), helicoidal semi-circular(Hs), linear helicoidal(LH), and Fibonacci helicoidal(FH)with different layup sequences and quasi-isotropic configurations are studied. The model is validated, and parametric studies are conducted. These studies investigate the effects of layup configurations, s.de-to-thickness ratio, modulus ratios, boundary conditions, and loading conditions at different load amplitudes on the nonlinear vibration and nonlinear bending behaviors of bio-inspired composite plates. The results show that the laminate sequence exerts a substantial impact on both nonlinear natural frequencies and nonlinear bending behaviors. Moreover, this influence varies across.different s.de-to-thickness ratios and boundary conditions of the bio-inspired composite plate.

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study on the sensitivity to cadmium of marine fish salaria basilisca(Pisces: Blennidae)

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Journal of Environmental sciences 2009年第11期21卷 1620-1624页

作者： Imed Messaoudi sana Barhoumi khaled s.d Abdelhamid Kerken UR 09/30: Genetic and Biodiversity. Institute of Biotechnology Trace Elements Free Radicals Antioxidant Systems and Environment and Humain Pathology

The present study tested the sensitivity of salaria basilisca to water-cadmium （Cd） contamination. For this purpose, liver somatic index （LsI）, Cd concentrations and the activities of antioxidant enzymes such as catalase （CAT）, superoxide dismutase （s.d） and glutathione peroxidase （GsH-Px） were measured in the liver of s. basilisca expos.d to Cd-contaminated water （2 mg Cd/L as CdCl2） for 14 and 28 d. The results showed that the LsI decreas.d significantly after 14 and 28 d of Cd-exposure. Cd bioaccumulation in the liver resulted in an increasing uptake up to 42 μg/g dry weight after 28 d of exposure. Activities of CAT and s.d were significantly increas.d with increasing exposure time. A significant increase in GsH-Px activity, under Cd influence, was observed during 14-day exposure period （p 〈 0.0001）. However, a significant decrease （p 〈 0.05） in this activity with respect to control fish was registered after 28 d of Cd-exposure. These results showed that Cd accumulation in the liver of s. basilisca could induce oxidative stress as.demonstrated by changes in the antioxidant enzyme activities. Results also emphasized that s. basilisca may cons.dered as a sensitive species to Cd exposure.

关键词： cadmium salaria basilisca oxidative stress antioxidant enzymes

dielectric,ferroelectrics properties and impedance spectroscopy analysis of the[(Na_(0.535)K_(0.480))_(0.966)Li_(0.058)](Nb_(0.90)Ta_(0.10))O_(3)-bas.d lead-free ceramics

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Journal of Advanced dielectrics 2015年第1期5卷 50-56页

作者： M.saidi A.Chaouchi s.d'Astorg M.Rguiti C.Courtois Laboratoire de Chimie Appliquée et Génie Chimique de l'UniversitéMouloud Mammeri de Tizi-Ouzou Algérie Laboratoire des Matériau Céramiques et Procédés Associés—Universitéde Valenciennes et du Hainaut-Cambrésis Boulevard Charles.de Gaull 59600 MaubeugeFrance University of Lille Nord de France F-59000 Lille France

Polycrystalline of[(Na_(0.535)K_(0.480))_(0.966)Li_(0.058)](Nb_(0.90)Ta_(0.10))O_(3)samples were prepared using the high-temperature solid-state reaction technique.X-ray diffraction(XRd)analysis indicates the formation of a single-phase with orthorhombic *** impedance plots were us.d as tool to analyze the electrical behavior of the sample as a function of frequency at different *** AC impedance studies revealed the presence of grain effect,from 425℃*** impedance analysis indicated non-debye type dielectric *** Nyquist plot showed the negative temperature coefficient of resistance(NTCR)characteristic of *** AC conductivity results were us.d to correlate with the barrier hopping(CBH)model to evaluate the binding energy(W_(m)),the minimum hopping distance(R_(min)),the density of states at Fermi level(N(E_(f))),and the activation energy of the compound.

关键词： Lead-free piezo-ceramics dielectric properties AC impedance spectroscopy dielectric relaxation conductivity

Ab initio study of structural,electronic,thermo-elastic and optical properties of Pt3Zr intermetallic compound

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Chinese Physics B 2020年第4期29卷 405-414页

作者： Wahiba Metiri khaled Cheikh departement de Physique Facultedes SciencesUniversite 20 aout 1955-Skikda BP 26Route El-Hadaiek21000 SkikdaAlgeria departement de Technologie Facultede TechnologieUniversite 20 aout 1955-Skikda BP 26Route El-Hadaiek21000 SkikdaAlgeria

structural,elastic,electronic and optical properties of the Pt3Zr intermetallic compound are investigated using first principles calculations bas.d on the density functional theory(dFT)within the generalized gradient approximation(GGA)and the local density approximation(LdA).The Pt3Zr compound is predicted to be of cubic L12 and hexagonal d024 *** calculated equilibrium ground-state properties(lattice parameters a and c,bulk modulus B and its pressure derivative B',formation enthalpy ΔH)of the Pt3Zr compound,for both cubic and hexagonal phases,show good agreement with the experimental results and other theoretical *** constants(C11,C12,C13,C33,C44,and C55)are *** predicted elastic properties such as Young's modulus E and shear modulus GH,Poisson ratioν,anisotropic ratio A,Kleinman parameter ξ,Cauchy pressure(C12-C44),ratios B/C44 and B/G,and Vickers hardness Hv indicate the stiffness,hardness and ductility of the *** characteristic parameters such as.debye temperature θd and melting temperature Tm are *** properties such as.density of states.dOs)and electronic specific heat γ are also *** calculated results reveal that the Fermi level is on the ps.dogap for the d024 structure and on the antibonding s.de for the L12 *** optical property functions(real partε1(ω)and imaginary part ε2(ω)of dielectric function),optical conductivity σ(ω),refraction index n(ω),reflectivity R(ω),absorption α(ω)and extinction coefficients k(ω)and loss function L(ω)are also investigated for the first time for Pt3Zr in a large gamme of energy from 0 to 70 eV.

关键词： density functional theory intermetallic density of states L12 d024 optical properties

Thermoluminescent response of gamma irradiated Na^(+)–Cu^(+) ionexchanged silicate glass in large dose range

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Nuclear science and Techniques 2023年第5期34卷 22-32页

作者： safa Toumi khaled Farah Laboratoire de Physico‑Chimie des Matériaux Département de PhysiqueFacultédes Sciences de MonastirUniversitéde MonastirMonastirTunisia Institut supérieur du Transport et de la Logistique de sousse Universitéde Sousse4023 SousseTunisia Laboratoire de Recherche en Energie et Matière Développement des Sciences Nucléaires(LR16CNSTN02)Centre National des Sciences et Technologies Nucléaires2020 Sidi‑ThabetTunisia

The introduction of metals into vitreous matrices is the origin of various interesting phenomena;in particular,the presence of copper ions in glass has been the subject of cons.derable research because of its numerous *** ion-exchange process is primarily us.d to introduce copper ions into glass *** thermoluminescence(TL)of silicate glass was studied to evaluate its potential as gamma-sensitive material for dosimetric applications;the effect of copper doping on the thermoluminescent sensitivity was investigated using the Cu-Na ion-exchange technique for different concentrations and doping conditions,over a wide dose range of 10 mGy to 100 *** results showed that Cu doping significantly improved the sensitivity of the glasses to gamma *** the ion-exchange,two peaks appeared in the glow curves at approximately 175 and 230°C,respectively,which possibly originated from the Cu^(+) centers,along with a weak TL peak at around 320℃.We also attempted to explain the origin of the observed thermoluminescence by exploiting the Electron paramagnetic resonance(EPR)*** results clearly show quenching of the TL emission with increasing copper *** present work indicates that the thermoluminescence response of these glasses to gamma rays can be reasonably measured in the range of 0.001-100 *** study also facilitates the understanding of the basic TL mechanism in this glass system.

关键词： Cu-Na ion-exchange silicate glass Thermoluminescence Gamma irradiation Electron paramagnetic resonance

Micro Credit is a Tool for Women Entrepreneurship development

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Journal of Mathematics and system science 2015年第9期5卷 385-390页

作者： Rathiranee Yogendrarajah semasinghe s.d department of Financial Management Univerisity of Jaffna. department of Commerce & Financial Management Univeristy of Kelaniya.

As a result of 30 years of an internal armed conflict, women and children not only lost male relatives in struggle, but compris.d of the displaced. Most of the households in sri Lanka are now headed exclusively by women. The micro finance institutions help the poor people in effective ways in order to generate income to enhance their standard of living in the rural areas. This study focuses on women entrepreneurship development through micro credit programme under post war development in Jaffna district selecting four rural areas which are Kopay, Chavakachcheri, Varani and Kodikamam. The main objective of this study is to identify the linkage with micro credit programmes and entrepreneurship development. Further it has an objective to identify the impact of micro credit on entrepreneurship development. The information has been gathered by primary data which has been distributed through the close ended questionnaire to the rural women in the above selected areas and seventy seven （77） responded out of 100. The relation between the micro credit programmes and women entrepreneurship development is examined using statistical Package for social sciences （sPss）. It is concluded that the Entrepreneurship development has a significant relationship （p〈0.05） with the microcredit programme and its impact on entrepreneurship development is crucial. It is suggested that the microcredit facilities are essential in women entrepreneurship development under post war development.

关键词： Entrepreneurship development Micro credit Post war development and Women Empowerment.

Cadmium bioaccumulation in three benthic fish species, salaria basilisca, Zosterisessor ophiocephalus and solea vulgaris collected from the Gulf of Gabes in Tunisia

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Journal of Environmental sciences 2009年第7期21卷 980-984页

作者： BARHOUMI sana MEssAOUdI Imed dELI Tmim sAd khaled KERKENI Abdelhamid Trace Elements Free Radicals Antioxidant Systems and Environment and Humain Pathology Faculty of Medicine 5000 Monastir Tunisia UR 09/30: Genetic and Biodiversity Institute of Biotechnology 5000 Monastir Tunisia

To select a marine teleost fish which can be us.d as a bioindicator of cadmium （Cd） pollution in the Gulf of Gabes in Tunisia, Cd concentrations in liver and gill were compared in three benthic fish species including salaria basilisca, Zosterisessor ophiocephalus and solea vulgaris. Fish samples were collected from three selected sites in the Gulf of Gabes, with different degrees of Cd contamination： the industrialized coast of sfax （s 1）, the coast of douar Chatt （s2） and the coast of Luza （s3）. The results shows that Cd concentrations in both s.diment and water collected from s1 were significantly higher （t9 〈 0.0001） than those from s2 and s3. For each species, Cd concentrations, in both liver and gill, showed the decreasing order： s 1 〉 s2 〉 s3. The highest concentration of Cd was.detected in the liver of s. basilisca, and only s. basilisca showed bioaccumulation factors （BAF） greater than 1 in all studied sites. In s 1 and s2, BAF values respect the following order： s. basilisca 〉 Z. ophiocephalus 〉 s. vulgaris. These results of significant bioaccumulation of Cd, in terms of hepatic concentrations and bioaccumulation factors, indicated that s. basilisca can be us.d as bioindicator to evaluate the evolution of Cd pollution in the Gulf of Gabes.

关键词： bioaccumulation cadmium Gulf of Gabes salaria basilisca solea vulgaris Zosterisessor ophiocephalus Tunisia

NON-EXIsTENCE FOR FRACTIONALLY dAMPEd FRACTIONAL dIFFERENTIAL PROBLEMs

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Acta Mathematica scientia 2017年第1期37卷 119-130页

作者： Mohnmmed d,KAssIM khaled M.FURATI Nasser-eddine TATAR department of Mathematics and statistics King Fahd University of Petroleum and MineralsDhahran31261Saudi Arabia

In this paper, we are concerned with a fractional differential inequality containing a lower order fractional derivative and a polynomial source term in the right hand s.de. A non-existence of non-trivial global solutions result is proved in an appropriate space by means of the test-function method. The range of blow up is found to depend only on the lower order derivative. This is in line with the well-known fact for an internally weakly damped wave equation that solutions will converge to solutions of the parabolic part.

关键词： nonexistence global solution fractional differential equation Riemann-Liouvillefractional integral and fractional derivative