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Static and dynamic responses of a microcantilever with a T-shaped tip mass to an electrostatic actuation

Acta mechanica Sinica 2016年第6期32卷 1104-1122页

作者： B.Firouzi m.Zamanian S.A.A.Hosseini Department of mechanical Engineering Faculty of Engineering Kharazmi University

In this study, nonlinear static and dynamic responses of a microcantilever with a T-shaped tip mass excited by electrostatic actuations are investigated. The electrostatic force is generated by applying an electric voltage between the horizontal part of T-shaped tip mass and an opposite electrode plate. The cantilever microbeam is modeled as an Euler-Bernoulli beam. The T-shaped tip mass is assumed to be a rigid body and the nonlinear effect of electrostatic force is considered. An equation of motion and its associated boundary conditions are derived by the aid of combining the Hamilton principle and Newton’s method. An exact solution is obtained for static deflection and mode shape of vibration around the static position. The differential equation of nonlinear vibration around the static position is discretized using the Galerkin method. The system mode shapes are used as its related comparison functions. The discretized equations are solved by the perturbation theory in the neighborhood of primary and subharmonic resonances. In addition, effects of mass inertia, mass moment of inertia as well as rotation of the T-shaped mass, which were ignored in previous works, are considered in the analysis. It is shown that by increasing the length of the horizontal part of the T-shaped mass, the amount of static deflection increases, natural frequency decreases and nonlinear shift of the resonance frequency increases. It is concluded that attaching an electrode plate with a T-shaped configuration to the end of the cantilever microbeam results in a configuration with larger pull-in voltage and smaller nonlinear shift of the resonance frequency compared to the configuration in which the electrode plate is directly attached to it.

关键词： mEmS Electrostatic Static deflection Natural frequency Pull-in voltage Perturbation theory T-shaped mass Primary and subharmonic resonances

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modern treatment strategies for penile prosthetics in Peyronie’s disease:a contemporary clinical review

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Asian Journal of Andrology 2020年第1期22卷 51-59页

作者： matthew J Ziegelmann m Ryan Farrell Laurence A Levine Division of Urology Rush University Medical CenterChicagoIL 60612USA

Peyronie's disease is a common condition resulting in penile deformity,psychological bother,and sexual *** dysfunction is one common comorbid condition seen in men with Peyronie’s disease,and its presence significantly impacts treatment *** a man with Peyronie's disease and significant erectile dysfunction who desires the most reliable treatment,penile prosthesis placement should be strongly *** some instances,such as those patients with relatively mild curvature,prosthesis placement alone may result in adequate ***,many patients will require additional straightening maneuvers such as manual modeling,penile plication,and tunica albuginea incision with or without *** patients with severe penile shortening,penile length restoration techniques may also be ***,we provide a comprehensive clinical review of penile prosthesis placement in men with Peyronie's ***,we discuss preoperative indications,intraoperative considerations,adjunctive straightening maneuvers,and postoperative outcomes.

关键词： collagenase grafting penile length penile prosthesis Peyronie's

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Temperature Uniformity,Correlations and the Flow Field in Swirling Impinging Jets

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Journal of Thermal Science 2023年第2期32卷 662-679页

作者： Zahir U.AHmED Yasir m.AL-ABDELI Department of mechanical Engineering Khulna University of Engineering&TechnologyKhulna 9203Bangladesh School of Engineering Edith Cowan UniversityJoondalupWA 6027Australia

Infrared thermography,velocity and impingement pressure measurements alongside numerical modelling are used in this study to resolve(heated)surface temperature distributions of turbulent swirling impinging jets for two Reynolds numbers(Re=11600 and 24600).Whilst building upon earlier discoveries for this same geometry,this paper provides three new contributions:(1)identifying the role of impingement distance(H/D)as a deciding factor in the trade-off between more efficient heat transfer(at high swirl numbers)and achieving better substrate temperature uniformity(lower gradients),(2)developing correlations to predict Nusselt number for swirling and non-swirling cooling jets,and(3)predicting the underlying mixing field in these jets and its interplay with the thermal distributions *** indicate substrate temperature uniformity varies based on H/D and swirl intensity(S)with a significant level of thermal non-uniformity occurring in near-field impingement(H/D=1)at stronger swirl(S=0.59 and 0.74).Four correlations describing the effects of S,Re,and H on the average heat transfer and stagnation heat transfer are developed and yield accuracies of 8%and 12%,*** recirculation near the impingement surface is predicted at H/D=1 for stronger swirl jets which disappears at other substrate *** peak wall shear stress reduces and the flow impingement becomes radially wider at higher H/D and *** turbulence or eddy viscosity regions for non-swirling jets(S=0)are predicted in the shear layer and entrainment regions at H/D=1,but such turbulence is confined to the impingement and wall jet regions for strongly swirling flows.

关键词： Temperature uniformity Nusselt number IR imaging CTA RANS

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Kinetic Study on CO_2 Reforming of methane

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Chinese Journal of Chemical Engineering 2001年第2期9卷 190-195页

作者： C.E.Quincoces m.G.González Centro de Investigacion y Desarrollo en Procesos Cataliticos (CINDECA) 阿根廷

The kinetics of CO2 reforming of methane has been studied at 976－1033K on a commercial NiO/CaO/Al2O3 catalyst in a packed-bed continuous reactor. The reaction was carried out at atmospheric pressure and CO2/CH4 ratio ＞ 2. The Hougen-Watson rate models were fitted to experimental data assuming the disso ciative adsorption of methane as the rate-determining step. The reaction rate showed an effective reaction order of about unity for CH4. The apparent activity energy was found to be 104 kJ·mol-1. Therefore the kinetic reaction parameters were determined and a possible reaction mechanism was proposed.

关键词： CH4 reforming Ni catalysts syngas

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New approaches to cognitive work analysis through latent variable modeling in mining operations

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International Journal of mining Science and Technology 2019年第4期29卷 549-556页

作者： S.Li Y.A.Sari m.Kumral Department of mining and materials Engineering McGill University

This paper discusses the utilization of latent variable modeling related to occupational health and safety in the mining *** variable modeling,which is a statistical model that relates observable and latent variables,could be used to facilitate researchers’understandings of the underlying constructs or hypothetical factors and their magnitude of effect that constitute a complex *** enhanced understanding,in turn,can help emphasize the important factors to improve mine *** most commonly used techniques include the exploratory factor analysis(EFA),the confirmatory factor analysis(CFA)and the structural equation model with latent variables(SEm).A critical comparison of the three techniques regarding mine safety is *** applications of latent variable modeling in mining engineering are *** this scope,relevant research papers were *** suggest that the application of such methods could prove useful in mine accident and safety *** of latent variables analysis in cognitive work analysis was proposed to improve the understanding of human-work relationships in mining operations.

关键词： Latent variables Exploratory factor analysis Confirmatory factor analysis Structural equation modeling Occupational health and safety mine safety

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mesoporous WO_3-graphene photocatalyst for photocatalytic degradation of methylene Blue dye under visible light illumination

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Journal of Environmental Sciences 2018年第4期30卷 328-337页

作者： Adel A.Ismail m.Faisal Adel Al-Haddad Wastewater Treatment and Reclamation Technologies (WTRT) Water Research Center Kuwait Institute for Scientific Research Advanced materials and Nano-Research Centre Najran University

Advanced oxidation technologies are a friendly environmental approach for the remediation of industrial wastewaters. Here, one pot synthesis of mesoporous WO3 and WO3-graphene oxide（GO） nanocomposites has been performed through the sol–gel method. Then, platinum（Pt） nanoparticles were deposited onto the WO3 and WO3-GO nanocomposite through photochemical reduction to produce mesoporous Pt/WO3 and Pt/WO3-GO nanocomposites. X-ray diffraction（XRD） findings exhibit a formation of monoclinic and triclinic WO3 phases. Transmission Electron microscope（TEm） images of Pt/WO3-GO nanocomposites exhibited that WO3 nanoparticles are obviously agglomerated and the particle sizes of Pt and WO3 are ~ 10 nm and 20–50 nm, respectively. The mesoporous Pt/WO3 and Pt/WO3-GO nanocomposites were assessed for photocatalytic degradation of methylene Blue（mB） as a probe molecule under visible light *** findings showed that mesoporous Pt/WO3, WO3-GO and Pt/WO3-GO nanocomposites exhibited much higher photocatalytic efficiencies than the pure WO3. The photodegradation rates by mesoporous Pt/WO3-GO nanocomposites are 3, 2 and 1.15 times greater than those by mesoporous WO3, WO3-GO, and Pt/WO3, respectively. The key factors of the enhanced photocatalytic performance of Pt/WO3-GO nanocomposites could be explained by the highly freedom electron transfer through the synergetic effect between WO3 and GO sheets, in addition to the Pt nanoparticles that act as active sites for O2 reduction, which suppresses the electron hole pair recombination in the Pt/WO3-GO nanocomposites.

关键词： mesoporous Pt/WO3 nanocomposites Graphene oxide methylene Blue photodegradation Visible light

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The Radiation Loss of a Cylindrical methane-Argon Plasma Arc

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Plasma Science and Technology 2010年第2期12卷 218-223页

作者： B.LIANI R.BENALLAL m.LEmERINI Theoretical Physics Laboratory Sciences Faculty University of Tlemcen

Calculation of the net radiation emitted by a CH4-Ar mixture, in a temperature range of 5,000-30,000 K with the assumption of local thermodynamic equilibrium （LTE）, is conducted. Continuum and line emissions are taken into account. The radiative transfer of each line is calculated by means of an escape factor depending on the shape and broadening of the line. Assuming a cylindrical, homogeneous, and isothermal plasma, the net emission coefficient is calculated for different pressures between 1 atm and 10 atm and arc radia of 0 mm to 1 mm. Results show that the argon presence in the CH4-Ar mixture has a significant effect on the total radiation emitted for the temperature above 17,000 K and the results for pure argon agree with those of BAUDER and EVANS.

关键词： thermal plasma methane argon radiation loss radiative transfer equation

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Effect of Lorentz forces on forced-convection nanofluid flow over a stretched surface

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Particuology 2016年第3期14卷 108-113页

作者： mohsen Sheikholeslami m.T. mustafa Davood Domiri Ganji Department of mechanical Engineering Babol University of Technology Babol Islamic Republic oflran Department of mathematics Statistics and Physics Qatar University Doha 2713 Qatar

magnetic nanofiuid hydrothermal analysis over a plate is studied that includes consideration of thermal radiation. The Runge-Kutta （RK4） method is utilized to get solution of ODEs which are obtained from similarity solution. In considering the impacts of Brownian motion, we applied Koo-Kleinstreuer-Li cor- relation to simulate the properties of CuO-water. The influence is discussed of important parameters such as the temperature index, magnetic, radiation, and velocity ratio parameters and volume fraction of nanoparticle on hydrothermal behavior. Results illustrate that the coefficient of skin friction enhances with enhancing magnetic parameter while reduces with enhancing velocity ratio parameter. Also the Nusselt number was found to directly depend on the velocity ratio and temperature index parameters but has an inverse dependence on the magnetic and radiation parameters.

关键词： Nanofluid Brownian motion Thermal radiation magnetohydrodynamic Stretching sheet

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Spin-Relaxation of NiO Encapsulated Gd_2O_3 Core–Shell Nanoparticles

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Acta metallurgica Sinica(English Letters) 2014年第2期27卷 253-258页

作者： A.Rajesh m.manivel Raja K.Gurunathan Department of Nanoscience and Technology Science BlockAlagappa University Defence metallurgical Research Laboratory

Nickel oxide encapsulated gadolinium oxide （Gd203~IiO） core-shell nanoparticles （Nps） has been synthesized by polyol method and analyzed by transmission electron microscopy. The particle size is found to vary from 25 to 35 nm. Raman spectra show the gadolinium oxide core material peaks are found to be diminished by the mass effect of the NiO shell material. The dynamics of the magnetic moment has been studied with the help of temperature dependent electron paramagnetic resonance （EPR） spectroscopy. Peak-to-peak line width （AHpp） value of the EPR spectra increases with decreasing temperature. Temperature dependence of line width shows the dominance of spin-lattice relaxation in these systems, and it can be used as T~ contrast agent. Spin number estimated from EPR studies increases with the decrease of the temperature. The interfacial exchange coupling between the core and shell region is found to be existing at very low temperatures as determined by EPR studies in this non-magnetic/antiferromagnetic （Nm/AFm） core/shell nanosystem. The effects of the temperature on the magnetic properties of the Gd203/NiO core/shell NPs and the underlying mechanism have been discussed.

关键词： Nanocomposite magnetic material Raman spectroscopy Electron paramagnetic resonance(EPR) Spin-relaxation

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Local and range-wide distribution of song types suggest Ovenbirds(Seiurus aurocapilla)have song neighborhoods but not macro-dialects

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Avian Research 2023年第2期14卷 191-199页

作者： Patrick m.Jagielski Jennifer R.Foote Department of Biology Algoma UniversitySault Ste.MarieONCanada

The song systems of oscine passerines(songbirds)are complex and *** songs are used for both mate attraction and territory defense and are therefore important signals for survival and reproduction,comprehensive knowledge of within and among species song structure and distribution is informative for understanding the evolution of song repertoires and vocal *** this study,we explored variation in the song structure of the Ovenbird(Seiurus aurocapilla),a widespread warbler(Family Parulidae)found in North American *** analyzed recordings from the 2021 breeding season to assess song type variation at a local(n=158 birds;Sault ***,ON)and breeding range scale(n=512 birds;eBird).We characterized the local song types and tested whether Ovenbirds share song types with their neighbors more often than expected by *** then characterized song types of Ovenbirds across the breeding range to determine whether any geographic pattern of song clustering exists(i.e.,macro-dialects).We found 10 distinct song types and some evidence for song type clustering at the local study site(i.e.,song neighborhoods).We found 7 of those 10 song types throughout the breeding range and identified an additional 24 types that were not recorded in our local *** found no evidence for song dialects across the Ovenbird breeding *** study contributes to our understanding of Ovenbird song while simultaneously adding to our understanding of geographic structuring of warbler *** work contributes to delineating a more comprehensive understanding of factors affecting dialect development for this diverse group of songbirds.

关键词： Dialects eBird Geographic variation Ovenbird Parulidae Seiurus aurocapilla Song type

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