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Parameter Optimization study on Control of Distortion in Bright Bar Used In Rack Application subjected To Induction Heat Treatment

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材料热处理学报 2004年第5期25卷 579-581页

作者： k. Palaniradja N. Alagumurthi V. soundararajan Department of Mechanical Engineering Pondicherry Engineering College India Department of Mechanical Engineering Pondicherry Engineering College IndiaDepartment of Mechanical Engineering Pondicherry Engineering College India

The engineering properties of metals and alloys are related to their structures. The change in mechanical properties of the metals and alloys can be achieved by the process of heat treatment. Induction hardening is one such a process involves phase transformation by rapid heating and cooling of the outer surface. Induction hardening improves the outer surface hardness and wear resistant properties keeping the original toughness and ductility in the inner core. However past experiences shows that during heat treatment, parts have undergone dimensional changes due to thermal fluctuations and phase transformations. Dimensional changes can lead to excessive distortion in the component which always presented difficulties to the uses of many varieties of steels which can be hardened by induction hardening. The dimensional changes in components which have been induction hardened have for a long time proved costly and troublesome to manufacturers. These difficulties apply particularly in the automotive industry where the amount of distortion in rack and pinion assembly has been related to their noise level in operation and investigators have suggested a link between distortion and the initiation of fatigue failure. [1] Although the complete elimination of distortion would be an ideal aim, manufacturers are reconciled to the fact that a certain amount of distortion is an inherent part of the hardening process. However, if the amount of distortion is uniform and predictable, an allowance could be made in the initial machining operations. It was with these aims that investigations into the control of distortion in bright bar (EN 18D steel) used in rack application (Power steering assembly) have been carried out by parameter optimization

关键词：感应加热淬火变形 EN18D钢析因法回归模型

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Interferences in photo-detached electron spectra from a non-collinear tri-atomic anion

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Chinese Physics B 2014年第10期23卷 114-117页

作者： A.Afaq k.Farooq M.A.khan 衣学喜 Center of Excellence in solid state Physics University of the Punjab school of Physics and Optoelectronic Technology Dalian University of Technology

The electron flux oscillations in photo-detachment of a non-collinear tri-atomic anion have been studied by taking each atom of the system as a coherent source of detached-electron wave. These electron waves traversing along three different trajectories result in a quantum interference. An analytical expression of detached-electron flux is evaluated for various detached-electron energies and for different geometrical shapes of the system. The results show that the electron flux distributions exhibit molecular shape-induced oscillatory structures. These oscillations are explained using the semi- classical closed-orbit theory; the outgoing electron waves produced from one center are propagated in the vicinity of the sources at other centers. It is also observed that in a particular case our non-collinear tri-atomic system reduces to the collinear tri-atomic system recently published.

关键词： electron flux collinear tri-atomic system quantum interference

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A Note on the Invariance Properties and Conservation Laws of the kadomstev–Petviashvili Equation with Power Law Nonlinearity

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Chinese Physics Letters 2011年第9期28卷 10-11页

作者： A H Bokhari F D Zaman k Fakhar A H kara Department of Mathematical sciences King Fahd University of Petroleum and MineralsDhahran 31261Saudi Arabia Department of Mathematics Faculty of ScienceUniversiti Teknologi Malaysia81310 UTM SkudaiJohorMalaysia Ibnu sina Institute for Fundamental science studies Universiti Teknologi Malaysia81310 UTM SkudaiJohorMalaysia school of Mathematics University of the WitwatersrandJohannesburgWits 2050South Africa

First,we studied the invariance properties of the kadomstev–Petviashvili equation with power law ***,we determined the complete class of conservation laws and stated the corresponding conserved densities which are useful in finding the conserved quantities of the *** point symmetry generators were also used to reduce the equation to an exact solution and to verify the invariance properties of the conserved flows.

关键词： equation conserved equation

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Elastic Properties of Potassium Halides under Pressure

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Journal of Materials science & Technology 2008年第2期24卷 241-244页

作者： k.Haddadi L.Louail D.Maouche Department of Physics Faculty of SciencesUniversity of SetifAlgeria

The moderate-pressure elastic properties of potassium halides kX （X=F, Cl, Br） was studied theoretically using the density functional theory （DFT） with normconserving pseudopotentials method. The phase transformation from the B1 phase （NaCl-type structure） to the denser B2 phase （CsCl-type structure） occurred at 7.7, 3.46 and 2.96 GPa for kF, kCI and kBr, respectively. The elastic stiffness coefficients and bulk modulus of these materials were calculated as function of hydrostatic pressure and compared with both the experimental and theoretical values.

关键词： Phase transitions Elastic coefficients solid alkali halides

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Root system Traits Contribute to Variability and Plasticity in Response to Phosphorus Fertilization in 2 Field-Grown sorghum[sorghum bicolor(L.)Moench]Cultivars

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Plant Phenomics 2023年第1期5卷 6-21页

作者： Michael O.Adu Paul A.Asare David O.Yawson kwadwo k.Amoah kofi Atiah Matthew k.Duah Alex Graham Department of Crop science School of AgricultureCollege of Agriculture and Natural SciencesUniversity of Cape CoastCape CoastGhana Centre for Resource Management and Environmental studies(CERMEs) The University of the West IndiesCave Hill CampusP.O.Box 64Bridgetown BB11000Barbados Department of soil science School of AgricultureCollege of Agriculture and Natural SciencesUniversity of Cape CoastCape CoastGhana

Due to roots'physical and physiological roles in crop productivity,interest in root system architecture(RsA)and plasticity in responses to abiotic stresses is *** is significant for the food security of millions of *** deficiency is an important limitation of sorghum *** is little information on the RsA-based responses of sorghum to variations in external P supply([P]_(ext)).This study evaluated the phenotypic plasticity and RsA responses to a range of[P]_(ext) in 2 sorghum *** results showed that both genotypes responded to[P]_(ext) but with significant variations in about 80%of the RsA traits *** biomass and most RsA traits increased with increasing[P]_(ext).Plasticity was both genotype-and *** most RsA traits,the white sorghum genotype showed significantly higher plasticity than the red genotype,with the former having about 28.4%higher total plasticity than the *** traits,such as convex area,surface area,total root length,and length diameter ranges,showed sizeable genetic *** biomass had a high degree of plasticity,but root number and angle traits were the leading contributors to *** results suggested 2 root trait spectra:root exploration and developmental spectrum,and there was an indication of potential trade-offs among groups of root *** is concluded that RsA traits in sorghum contribute to variability and plasticity in response to[P]_(ext).Given that there might be trade-offs among sorghum root traits,it would be instructive to determine the fundamental constraints underlying these trade-offs.

关键词： Root instru constraints

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Evaluation of boring machine performance with special reference to geomechanical characteristics

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International Journal of Minerals,Metallurgy and Materials 2009年第6期16卷 615-619页

作者： k. Goshtasbi M. Monjezi P. Tourgoli Faculty of Engineering Tarbiat Modares University

The duration of tunneling projects mostly depends on the performance of boring machines. The performance of boring machines is a function of advance rate, which depends on the machine characterizations and geomechanical properties of rock mass. There were various theoretical and empirical models for estimating the advance rate. In this paper, after determining the geomechanical properties of rock mass encountered in the Isfahan metro tunnel, the performance of the roadheader and tunnel boring machine （TBM） were then evaluated using various models. The calculation results show that the average instantaneous cutting rate of the roadheader in sandstone and shale are 42.8 and 74.5 m^3/h respectively. However the actual values in practice are 34.2 and 51.3 m^3/h. The operational cutting rate of the roadheader in sandstone and shale are 8.2 and 9.7 m^3/h respectively, but the actual values are 6.5 and 6.7 m^3/h. The penetration rate of the TBM in shale is predicted to be 50-60 mm/round.

关键词： performance prediction roadheader cutting rate specific energy tunnel boring machine penetration rate

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A New Duplex Reverse Transcription PCR for simultaneous Detection of Viable Cryptosporidium parvum Oocysts and Giardia duodenalis Cysts

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Biomedical and Environmental sciences 2010年第2期23卷 146-150页

作者： sEHEE NAM GYUCHEOL lee Water Analysis and Research Center K-water Daejeon 306-711 Republic of Korea

Objective To simultaneously detect viable Cryptosporidium parvum oocysts and Giardia duodenalis cysts for the purpose of reducing time and cost spent. Methods A duplex reverse transcription polymerase chain reaction （RT-PCR） method was newly developed. Results Using duplex RT-PCR method for the hsp70 gene, viable （oo）cyst concentrations of 10^1 and l0^3 （oo）cysts/100 *** could be detected for C. parvum and G duodenalis, respectively. However, after heat-shock.s.imulation the expression of hsp70 mRNAs was detectable at 10^0 and 10^1 （oo）cysts/100 μL concentrations of C. parvum and G. duodenalis, respectively. Thus, the detection sensitivity was significantly increased when the viable （oo）cysts were exposed to heat shock. Conclusion This study describes a new duplex RT-PCR method for hsp70 gene to detect the viable （oo）cysts of the C. parvum and G duodenalis with less time consumed and at a lower cost. This newly developed duplex RT-PCR method may be used to detect these parasites not only in aquatic environments but also in clinical samples.

关键词： Cryptosporidiumparvum Giardia duodenalis Heat-shock RT-PCR

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Assessment of bisphenols in children's toy and baby products in the Middle East

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Emerging Contaminants 2024年第3期10卷 336-342页

作者： k.Martínez-Guijarro B.Gevao M.Porcelli s.Al-salem saif Uddin M.Bahloul H.Taqi M.Hajeyah D.krishnan s.Rajagopalan A.Boota Environment Pollution and Climate Program Kuwait Institute for Scientific ResearchP.O.Box 23884SafatKuwait EPA Sierra Leone

A major concern from the scientific community has been raised since evidence of Bisphenol A(BP-A)can leach out from the products where they are incorporated as well as its endocrine disrupting effects observed in animals and ***-A and several related chemicals such as Bisphenol AP(BP-AP),Bisphenol B(BPeB),Bisphenol s(BPes),Bisphenol AF(BP-AF),Bisphenol(BPeP),Bisphenol Z(BP-Z)were analyzed in this ***-A and BP-s were the only bisphenols detected in the samples analyzed in this *** median(range;mean)concentrations of BP-A found in this study was 321 ng/g(11-200932;4893 ng/g).The analysis was carried out by sonicating 0.1 g of a cryo-milled sample aliquot in methanol followed by UPLC-Ms/Ms *** concentrations of BP-A were found in several products labeled as BP-A free such as nursing bottles which are particularly problematic from the children's exposure point of *** study presents the first reliable bisphenols in children's toys and baby products commercialized in the Middle *** is,however,a need to continue monitoring these compounds,especially in low-cost toys,and the so-called BP-A-free products,which appear to have high levels of target contaminants and can pose an exposure risk for infants and children in the region.

关键词： Bisphenols Bisphenol A(BP-A) Bisphenol s(BPes) Children Toys

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Axisymmetric stagnation-Point Flow with a General slip Boundary Condition over a Lubricated surface

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Chinese Physics Letters 2012年第2期29卷 126-129页

作者： M.sajid k.Mahmood Z.Abbas The Abdus salam International Centre for Theoretical Physics Strada Costiera 1134014TriesteItaly Department of Mathematics Riphah International UniversityIslamabad 44000Pakistan Department of Mathematics The Islamia University of BahawalpurBahawalpurPakistan

We investigate the axisymmetric stagnation-point flow of a viscous fluid over a lubricated surface by imposing a generalized slip condition at the fluid-fluid *** power law non-Newtonian fluid is considered as a *** lubrication layer is thin and assumed to have a variable *** transformed nonlinear ordinary differential equation governing the flow is linearized using *** method of superposi-tion is adopted to convert the boundary value problem into an initial value problem and the solution is obtained numerically by using the fourth-order Runge-kutta *** results are discussed to see the influence of pertinent *** limiting cases of Navier and no-slip boundary conditions are obtained as the special cases and found to be in excellent agreement with the existing results in the literature.

关键词： boundary ordinary assumed

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Environmentally friendly wollastonite@TiO2 composite particles prepared by a mechano-chemical method

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Particuology 2018年第5期16卷 105-112页

作者： Xifeng Hou Yihe Zhang Hao Ding Paul k.Chu Beijing key Laboratory of Materials Utilization of Nonmetallic Minerals and solid Wastes National Laboratory of Mineral MaterialsSchool of Materials Science and TechnologyChino University of Geosciences (Beijing)Beijing100083China Niushan Mining Co. Ltd.Tongling CountyAnhui 244131China Department of Physics and Materials science City University ofHong KongTat Chee AvenueKowloonHong KongChina

Core-shell wollastonite@ TiO2(WOT)composite particles are prepared by a mechano-chemical method (MCM)to improve the dispersion of TiO2and reduce its dosage,and to achieve synergistic effects with the wollastonite *** crystal structure,morphology,functional groups,and pigment properties of the as-prepared composite powders are *** W@T composite particles are formed by van der Waals force in addition to electrostatic attraction and chemical *** anatase TiO2coating is anchored on the woUastonite surface by si-O-Ti and Ca-O-Ti *** W@T powders possess excellent characteristics such as whiteness of 96.6%,hiding power of 17.97g/m^2,and oil absorption of 22.72g/*** properties of the W@T composite are similar to those of TiO2and the former,which is much cheaper,can potentially substitute the latter as a white paint in many applications.

关键词： Wollastonite TiO2 Composite particles Mechano-chemical method

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