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3D finite element prediction of chip flow, burr formation, and cutting forces in micro end-milling of aluminum 6061-T6

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Frontiers of mechanical Engineering 2017年第2期12卷 203-214页

作者： A. DAVOUDINEJAD p. pARENTI m. ANNONI mechanical Engineering Department Politecnico di Milano Milan20156 Italy

Abstract predictive models for machining operations have been significantly improved through numerous methods in recent decades. This study proposed a 3D finite element modeling （3D FEm） approach for the micro end-milling orAl6061-T6. Finite element （FE） simulations were performed under different cutting conditions to obtain realistic numerical predictions of chip flow, burr formation, and cutting forces. FE modeling displayed notable advantages, such as capability to easily handle any type of tool geometry and any side effect on chip formation, including thermal aspect and material property changes. The proposed 3D FE model considers the effects ofmiU helix angle and cutting edge radius on the chip. The prediction capability of the FE model was validated by comparing numerical model and experimental test results. Burr dimension trends were correlated with force profile shapes. However, the FE predictions overestimated the real force magnitude. This overestimation indicates that the model requires further development.

关键词： 3D finite element modeling micro end-milling cutting force chip formation burr formation

Approximants in annealed IQC(Icosahedral Quasicrystal)-DQC(Decagonal Quasicrystal) pseudo-binary alloys

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中国有色金属学会会刊：英文版 2003年第6期13卷 1360-1366页

作者：雷奕 J.m.Dubois m.Calvo-Dahlborg 黑祖昆 p.Weisbecker 董闯 State Key Laboratory for materials modification LSG2m CNRS-UmR7584 Institute of material & Technology

The structure and microstructure of constituent phases in annealed IQC100-xDQCx alloys, made from mixtures of (Al62Cu25.5Fe12.5) icosahedral quasicrystal （IQC） and (Al70Co15Ni15) decagonal quasicrystal （DQC）, were studied by X-ray diffractometry（XRD）, scanning electron microscopy （SEm）, and energy-dispersive X-ray spectroscopy （EDAX）. These constituent phases are mostly approximants: λ, β and τ3. In addition, an Al-Cu-Co DQC phase is observed in (IQC80DQC20) alloy. The nature of these approximants and their relationship with the quasicrystals（QCs） are discussed; and the evolution of these phases is interpreted by the shifting of their e/a-constant lines in the Al-（Cu, Ni）-（Fe, Co） pseudo-ternary phase diagrams.

关键词：二元合金准晶 IQC DQC 近似解退火相图

Cadmium sorption by sodium and thiourea-modified zeolite-rich tuffs

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Journal of Environmental Sciences 2017年第2期29卷 39-48页

作者： perfecto Barragán p m.Guadalupe macedo m maria T.Olguín Instituto Tecnologico de Toluca Laboratorio de Investigacion en Ingenieria Ambiental.Av.Tecnologico S/NColonia Ex-Rancho La VirgenMetepecEstado de Meico CP.52140Mexico Instituto National de Investigaciones Nucleares Departamento de QuimicaA.P.18-1027Col.EseandonDelegacion Miguel Hidalgo C.P.11801Mexico

In the present investigation, two zeolite-rich tuffs from Guaymas and El Cajon（State of Sonora）, which were conditioned with a sodium chloride solution and subsequently modified with a thiourea solution, were chosen to evaluate the removal of Cd from aqueous systems. The zeolitic materials were characterized by scanning electron microscopy and X-ray diffraction. The surface area was also determined. The experiments were performed in a batch system, and the influences of p H, contact time between phases, and the concentration of Cd in the solution on the adsorption by sodium or thiourea-modified zeolite-rich tuff were investigated. It was found that the efficiency of Cd ion removal from aqueous solutions is influenced by the p H of the aqueous systems. The Cd adsorption kinetic data were well fitted to a pseudo-second-order model in all cases. The Langmuir and Langmuir–Freundlich isotherms adequately described the Cd sorption behavior by the zeolite from El Cajon pretreated with Na Cl and the zeolite from Guaymas modified with thiourea, respectively.

关键词： Cadmium Zeolite-rich-tuff Sorption Kinetics Isotherms

Characterization of 1-Aminocyclopropane-1-Carboxylate(ACC) Deaminase-Containing pseudomonas *** the Rhizosphere of Salt-Stressed Canola

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pedosphere 2014年第4期24卷 461-468页

作者： A.R.AKHGAR m.ARZANLOU p.A.H.m.BAKKER m.HAmIDpOUR Department of Soil Science Vali-e-Asr University of RafsanjanRafsanjan(Iran) Department of Soil Science University of TabrizTabriz(Iran) Department of Biology Plant-Microbe InteractionsUtrecht UniversityUtrecht(Netherlands)

When exposed to biotic or abiotic stress conditions, plants produce ethylene from its immediate precursor 1-aminocyclopropane-1- carboxylate （ACC）, leading to retarded root growth and senescence. many plant growth-promoting rhizobacteria contain the enzyme ACC deaminase and this enzyme can cleave ACC to form a-ketobutyrate and ammonium, thereby lowering levels of ethylene. The aim of this study was to isolate and characterize ACC deaminase-producing bacteria from the rhizosphere of salt-stressed canola （Brassica napus L.）. Out of 105 random bacterial isolates, 15 were able to utilize ACC as the sole source of nitrogen. These 15 isolates were also positive for indole acetic acid （IAA） production. phylogenetic analysis based on partial 16S rDNA sequences showed that all isolates belonged to fluorescent pseudomonas spp. In the canola rhizosphere investigated in this study, pseudomonas fluorescens was the dominant ACC deaminase-producing species. Cluster analysis based on BOX-AIR-based repetitive extragenic palindromic-polymerase chain reaction （BOX-pCR） patterns suggested a high degree of genetic variability in ACC deaminase-producing p. fluorescens strains. The presence of indigenous ACC-degrading bacteria in the rhizosphere of canola grown in saline soils indicates that these bacteria may contribute to salinity tolerance.

关键词： BOX-AiR-based repetitive extragenic palindromie-polymerase chain reaction (BOX-pCR) ethylene indole acetic acid phylogenetic analysis plant growth-promoting rhizobacteria (pGpR) pseudomonas fluorescens

STABILITY RESULTS OF RANDOm ImpULSIVE SEmILINEAR DIFFERENTIAL EQUATIONS

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Acta mathematica Scientia 2014年第4期34卷 1055-1071页

作者： m.GOWRISANKAR p.mOHANKUmAR A.VINODKUmAR Department of mathematics Annapoorana Engineering College Salem- 636308Tamil NaduIndia Department of mathematics Arupadai Veedu Institute of Technology Chennai- 636104 Department of mathematics PSG College of Technology Coimbatore- 641004Tamil NaduIndia

In this paper, we study the existence, uniqueness, continuous dependence, Ulam stabilities and exponential stability of random impulsive semilineax differential equations under sufficient condition. The results are obtained by using the contraction mapping principle. Finally an example is given to illustrate the applications of the abstract results.

关键词： semilinear differential equations random impulses stability, Hyers-Ulam stability Hyers-Ulam-Rassias stability exponential stability contraction principle

preparation and Antibacterial Activity of Three-component NiFe_2O_4@pANI@Ag Nanocomposite

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Journal of materials Science & Technology 2014年第7期30卷 656-660页

作者： m.Kooti p.Kharazi H.motamedi Department of Chemistry Shahid Chamran UniversityAhvaz 61357-43169Iran Department of Biology Shahid Chamran UniversityAhvaz 61357-43169Iran

A new three-component and magnetically responsive NiFe2O4@pANI@Ag nanocomposite has been fabricated by coating of nickel ferrite, NiFe2O4, nanoparticles with polyaniline （pANI） and subsequent immobilization of silver nanoparticles onto the surface of polyaniline shell. The as-prepared nanocomposite has been characterized by X-ray diffraction （XRD）, Fourier transform infrared spectroscopy （FT-IR）, scanning electron microscopy （SEm）, and vibrating sample magnetometer （VSm）. The saturation magnetization of the NiFe2O4 core decreases dramatically after coating with polyaniline and silver nanoparticles, however, the nanocomposite NiFe2O4@pANI@Ag can be still separated from solution media through magnetic decantation. The antibacterial activity of the synthesized nanocomposite was studied and compared with those of naked NiFe2O4, NiFe2O4@pANI and some standard antibacterial drugs.

关键词： Antibacterial activity Nanocomposite Core/shell Ferrite magnetic nanoparticles Silver nanoparticles

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

Electroanalytical tools to investigate the divalent state of Eu(Ⅲ) and Nd(Ⅲ) ions in non-aqueous medium

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Journal of Rare Earths 2012年第4期30卷 392-396页

作者： Jignasu p mehta Himanshu m pandya Kahan I pandya Department of Chemistry DST-FIST sponsored Department Mahatma Gandhi Campus Bhavnagar University

The divalent state of Ln（III） ions has attracted much interest because of their ability to serve isomorphously in many biological system of divalent Ca（II） ion. Therefore, present paper deals with the study of divalent state of Eu（III） and Nd（III） ions in non-aqueous medium. In present study, cyclic voltammetry and chronopotentiometry were utilized to establish the divalent state of Eu（III） and Nd（III） ions. The cyclic voltammetric technique showed two-step reduction process at cathode for both Ln（III） ions under specified experimental conditions and chronopotentiometric method also showed two different transition times （r）. Looking to the shape of cyclic voltammogram we calculated het- erogeneous forward rate constant （K^fh, cm/s） and diffusion coefficient （D, cm2/s） for both ions, which suggested that sweep rate had great ef- fect on the shape of cyclic voltammogram of Eu（III） and Nd（III） ions. The result of chronopotentiometry also suggested that stable divalent states of Eu（III） and Nd（III） ions existed with chronopotentiogram with two distinct transition times. The diffusion coefficients （D, cm2/s） were calculated from Sand equation. The diffusion coefficients of both techniques were compared and the results suggested that the system at electrode surface was changing from being reversible to irreversible.

关键词： Eu(IlI) and Nd(III) ions non-aqueous medium cyclic-voltammetry chronopotentiomentry rare earths

Guest Editorial:Special Section on protection and Control of Smart Grid with High penetration of Converter Interfaced Generation Resources

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Journal of modern power Systems and Clean Energy 2021年第6期9卷 I0001-I0002页

作者： Juan m.Gers A.p.Sakis meliopoulos GERS WestonFLUSA Georgia Tech AtlantaGA.USA

ELECTRICAL system characteristics are changing substantially as the penetration levels of renewable generation and in general converter interfaced generation resources(CIGRs)*** operation of these systems constitutes a challenge for the engineering in protection and control *** of the importance of CIGRs for the modern power systems lies in the integration of renewable energy sources into the conventional distribution system,reducing the environmental impact and emissions.

关键词： Smart Converter system