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A one-dimensional basic oscillator model of the vircator
Posted on June 23rd, 2009 No commentsDebabrata Biswas<br/> A one-dimensional model of the virtual cathode oscillator (vircator) is proposed keeping only the essential physical processes. The basic model consists of a radiating charge in an oscillating electric field. Using parameters from (realistic) particle-in-cell simulations such as the charge Q and amp … [Phys. Plasmas 16, 063104 (2009)] published Mon Jun 22, 2009.
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Temperature modulation in ferrofluid convection
Posted on June 23rd, 2009 No commentsJitender Singh and Renu Bajaj<br/> Convective instability is suppressed by sinusoidal variation in temperature of horizontal boundaries of a ferrofluid layer subjected to vertical magnetic field. On increasing the amplitude of modulation, instability may arise in the form of oscillations which may have time period equal to that of th … [Phys. Fluids 21, 064105 (2009)] published Mon Jun 22, 2009.
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Stability of plane CouettePoiseuille flow of shear-thinning fluid
Posted on June 23rd, 2009 No commentsCherif Nouar and Ian Frigaard<br/> A linear stability analysis of the combined plane Couette and Poiseuille flow of shear-thinning fluid is investigated. The rheological behavior of the fluid is described using the Carreau model. The linearized stability equations and their boundary conditions result in an eigenvalue problem that is … [Phys. Fluids 21, 064104 (2009)] published Mon Jun 22, 2009.
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Macroscopic analysis of a turbulent round liquid jet impinging on an air/water interface in a confined medium
Posted on June 23rd, 2009 No commentsJerome Larocque, Nicolas Riviere, Stephane Vincent, David Reungoat, Jean-Pierre Faure et al.<br/> In this paper, a submerged vertical water jet impinging on an air/water free surface is experimentally and numerically investigated. On the one hand, a two dimensions-two components particle image velocimetry technique is carried out to perform velocity measurements from the jet injection to the uns … [Phys. Fluids 21, 065110 (2009)] published Mon Jun 22, 2009.
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Oscillatory shear induced droplet deformation and breakup in immiscible polymer blends
Posted on June 23rd, 2009 No commentsVitsarut Janpaen, Sumonman Niamlang, Wanchai Lerdwijitjarud, and Anuvat Sirivat<br/> Deformation and breakup of droplets in polybutadiene/polydimethylsiloxane blends subject to oscillatory shear flow were investigated experimentally using an optical shear flow cell. The apparent major axis (a) and the minor axis (c) in the vorticity direction of the droplets were measured as functio … [Phys. Fluids 21, 063102 (2009)] published Mon Jun 22, 2009.
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Brownian motion in RobertsonWalker spacetimes from electromagnetic vacuum fluctuations
Posted on June 23rd, 2009 No commentsCarlos H. G. Bessa, V. B. Bezerra, and L. H. Ford<br/> We consider the effects of the vacuum fluctuations of a quantized electromagnetic field on particles in an expanding universe. We find that these particles typically undergo Brownian motion and acquire a nonzero mean squared velocity that depends on the scale factor of the universe. This Brownian mo … [J. Math. Phys. 50, 062501 (2009)] published Mon Jun 22, 2009.
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Contact stress analysis of lightly compressed thin films: Modeling and experimentation
Posted on June 23rd, 2009 No commentsElon J. Terrell, M. Aslam Kabir, and C. Fred Higgs, III<br/> Although a number of models have been developed to describe the contact between nominally smooth surfaces, very few of these models have been validated with experiment. Therefore, in this study, an asperity-scale experimental contact measurement was conducted and compared to the predictions of two c … [J. Appl. Phys. 105, 124907 (2009)] published Mon Jun 22, 2009.
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In situ high energy x-ray synchrotron diffraction study of the synthesis and stoichiometry of LaFeAsO and LaFeAsOF
Posted on June 23rd, 2009 No commentsR. W. McCallum, J.-Q. Yan, G. E. Rustan, E. D. Mun, Yogesh Singh et al.<br/> The reaction path for the synthesis of LaFeAsO and LaFeAsOF by solid state reaction was studied by in situ high temperature x-ray diffraction technique and differential thermal analysis in the temperature interval 100 degrees C<=T<=1150 degrees C. Starting with LaAs, FeO, Fe, and LaF as precurso … [J. Appl. Phys. 105, 123912 (2009)] published Mon Jun 22, 2009.
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Mechanics of noncoplanar mesh design for stretchable electronic circuits
Posted on June 23rd, 2009 No commentsJ. Song, Y. Huang, J. Xiao, S. Wang, K. C. Hwang et al.<br/> A noncoplanar mesh design that enables electronic systems to achieve large, reversible levels stretchability (>100%) is studied theoretically and experimentally. The design uses semiconductor device islands and buckled thin interconnects on elastometric substrates. A mechanics model is established t … [J. Appl. Phys. 105, 123516 (2009)] published Mon Jun 22, 2009.
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Raman scattering of phonon-plasmon coupled modes in self-assembled GaN nanowires
Posted on June 23rd, 2009 No commentsK. Jeganathan, R. K. Debnath, R. Meijers, T. Stoica, R. Calarco et al.<br/> We report the determination of free-electron concentration and mobility of free-standing GaN nanowires (NWs) by line shape analysis of the coupled longitudinal optical phonon-plasmon Raman modes (L+). The E phonon mode at 566.9 cm with a sharp linewidth of 2.8 cm indicates strain free NWs with hig … [J. Appl. Phys. 105, 123707 (2009)] published Mon Jun 22, 2009.