2,780 research outputs found
ON THE PRE-JENSEN-GRUSS INEQUALITY
No full textSeveral pre-Jensen-Gruss inequalities for functions of n real variables are proved. The obtained inequalities are refinements of the Jensen-Gruss inequalities proved by Budimir and Pecaric
Analytical solutions to the shear strength of interfaces failing under flexure loading conditions
No full textFlexure experiments have been performed on steel substrates having a rib of methacrylate resin cast as a stiffener on the steel. Samples were loaded until resin delaminated from the substrate and the load at failure was recorded. An analytical solution for a composite beam was used to relate the force at failure to interfacial shear stress. This resulted in an average estimated shear strength of 490 kPa (71 psi) for a resin/steel interface. The accuracy of the analytic solution was examined using a three-dimensional finite element analysis (FEA). The FEA was also used to examine the assumptions of the first approximation analytic solution. The analytic solution can be applied more generally, considering the mechanical characteristics of both constituents, to design experiments that lead to a simplified determination of interfacial shear strength
Obituary: Dr M.K. Bhan – A True Leader & Visionary
No full text12The author remembers Dr M.K. Bhan as a true leader, visionary, a passionate scientist, doctor and a wonderful human being, who has given love and affection to everyone around him
M.K. Asante: “It’s Bigger than Hip Hop: Art, Race and Politics”
No full textIncludes descriptive metadata provided by producer in MPEG-4 video file: "Arts and Culture - Video - M.K. Asante: 'It’s Bigger than Hip Hop: Art, Race and Politics.'" By M.K. Asante. Author and filmmaker Asante delivers the annual Walter R. Murray, Jr., Lecture on Oct. 20, 2010 at the Commons Center. He takes questions after his lecture
Comparison study of dicyandiamide-cured epoxy bonded steel joints and polyamidoamine-cured epoxy bonded steel joints
No full textThere are instances where efficiency and safety may be compromised as a result of deteriorating fluid transport systems. Thus, it is worth evaluating other methods that can repair the damage for a temporary period without shutting down the operation. The objective was to evaluate the durability of an epoxy-bonded steel in aqueous environments that would represent such a repair. EPON® 828 was chosen as the epoxy resin, and dicyandiamide and polyamidoamine were two types of curing agents evaluated in this study. The epoxy-bonded steel joints were exposed in either distilled water or 3.4% NaCl solution for various times. The mechanical strength of the bonded joints was evaluated using a three-point flexure test. The interfacial shear strength of unaged samples ranged from 0.93 to 0.32 MPa. It was found that the interfacial shear strength decreased with aging time for both epoxy-bonded systems. Scanning electron microscopy (SEM), optical microscopy, and X-ray photoelectron spectroscopy (XPS) were used to determine the locus of failure of the bonded joints. It was concluded that failure occurred cohesively within the oxide layer if oxides were present on the substrate surface prior to the bonding procedure
A Unified Shell model for Buoyancy-Driven Turbulence
No full textWe construct a unified shell model for stably stratified and convective turbulence. Shell model simulation of stably stratified flow in turbulent regime exhibit Bolgiano-Obukhbov (BO) scaling in which the kinetic energy spectrum varies as . However, simulation of convective turbulence shows Kolmogorov's spectrum. These results are consistent with the direct numerical simulations of Kumar {\em et al.} [Phys. Rev. E {\bf 90}, 023016 (2014)]. We also observe a dual scaling ( and ) for a limited range of parameters in stably stratified flow
Sweeping has no effect on renormalized turbulent viscosity
No full textWe perform renormalization group analysis (RG) of the Navier-Stokes equation in the presence of constant mean velocity field , and show that the renormalized viscosity is unaffected by , thus negating the ``sweeping effect", proposed by Kraichnan [Phys. Fluids {\bf 7}, 1723 (1964)] using random Galilean invariance. Using direct numerical simulation, we show that the correlation functions for and differ from each other, but the renormalized viscosity for the two cases are the same. Our numerical results are consistent with the RG calculations
Energy transfers in small-scale and large-scale dynamos
No full textWe study energy transfers during magnetic energy growth in small-scale and large-scale dynamos. We perform direct numerical simulations for magnetic Prandtl number Pm =20 and 0.2 in a periodic box on 1024^3 grid. Energy fluxes and shell-to-shell energy transfers indicate that in small-scale dynamo for Pm =20, the magnetic energy growth takes place due to a non-local energy transfer from large-scale velocity field to small-scale magnetic field. On the other hand, in large-scale dynamo for Pm =0.2, local energy transfers from large-scale velocity field to large-scale magnetic field takes place
Author Correction: Long-range chiral exchange interaction in synthetic antiferromagnets
No full textIn the version of this Article originally published, the sentence ‘D.-S.H. wrote the paper with K.L., J.H. and M.K.’ in the author contributions was incorrect; it should have read ‘D.-S.H. wrote the paper with K.L., J.H., M.-H.J. and M.K.’ This has been corrected in the online versions of the Article
Implicit large-eddy simulation of the stratocumulus-topped boundary layer: A grid sensitivity study
No full textA range of implicit large-eddy simulations of the stratocumulus-topped boundary layer is performed to study the influence of grid resolution on selected parameters including liquid water path and second and third moments of vertical velocity fluctuations. The simulations are based on two sets of aircraft measurements, which are also used to evaluate the results of the simulations. The specific case presented here indicates that simulations with a grid aspect ratio accounting for the anisotropic nature of the turbulence near the surface and at the top of the boundary layer lead to better agreement with measurements than simulations with an isotropic grid
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