2,328 research outputs found

    Self Piercing Riveting for Metal-Polymer Joints

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    Self-Piercing Riveting (SPR) is a sheet metal joining technique based on the insertion of a rivet into two or more sheets, with no preparatory hole. This process has gained wide diffusion in the automotive industry, due to the increasing use of materials alternative to steel, that are difficult or impossible to join with traditional techniques. In particular, polymeric materials are becoming increasingly used, due to their favorable weight/strength ratio. This paper reports the results of experimental investigations, aimed at identifying the variables affecting the mechanical characteristics of mixed metal-plastic joints. A statistic model for the optimization of the geometrical parameters has been computed. The paper demonstrates that self-piercing riveting appears competitive for metal/polymer junction. The results analyzed in light of statistical techniques show that some geometrical parameters affect joint performance more than others and can therefore be used as independent variables for joint performance optimizatio

    Three-dimensional fast electron transport for ignition-scale inertial fusion capsules

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    Three-dimensional hybrid PIC simulations are presented to study electron energy transport and deposition in a full-scale fast ignition configuration. Multi-prong core heating close to ignition is found when a few GA, few PW beam is injected. Resistive beam filamentation in the corona seeds the 3D current pattern that penetrates the core. Ohmic heating is important in the low-density corona, while classical Coulomb deposition heats the core. Here highest energy densities (few Tbar at 10 keV) are observed at densities above 200 g/cc. Energy coupling to the core ranges from 20 to 30%; it is enhanced by beam collimation and decreases when raising the beam particle energy from 1.5 to 5.5 MeV.Comment: 5 pages, 5 figure

    Modelling Analytically the Dynamic Response of Thermo-Optic Phase Shifters

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    Thermo-optic phase shifters are widely adopted to achieve dynamical reconfiguration of integrated waveguide circuits [1], with applications encompassing diverse fields, ranging from free-space beam steering and shaping [2] to quantum information experiments [3]

    Co-Occurrence and Characteristics of Patients With Axial Spondyloarthritis Who Meet Criteria for Fibromyalgia : Results From a UK National Register

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    The British Society for Rheumatology (BSR) Biologics Register in Ankylosing Spondylitis is funded by the BSR and they have receive funds for this from Pfizer, AbbVie and UCB. These companies receive advance copies of manuscripts and can provide comments but have no input into determining the topics for analysis, publication and no input into the work involved in this analysis. This analysis is part-funded by Arthritis Research UK (Grant No: 21378)Peer reviewedPublisher PD

    Lattice Boltzmann study on Kelvin-Helmholtz instability: the roles of velocity and density gradients

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    A two-dimensional lattice Boltzmann model with 19 discrete velocities for compressible Euler equations is proposed (D2V19-LBM). The fifth-order Weighted Essentially Non-Oscillatory (5th-WENO) finite difference scheme is employed to calculate the convection term of the lattice Boltzmann equation. The validity of the model is verified by comparing simulation results of the Sod shock tube with its corresponding analytical solutions. The velocity and density gradient effects on the Kelvin-Helmholtz instability (KHI) are investigated using the proposed model. Sharp density contours are obtained in our simulations. It is found that, the linear growth rate Îł\gamma for the KHI decreases with increasing the width of velocity transition layer Dv{D_{v}} but increases with increasing the width of density transition layer Dρ{D_{\rho}}. After the initial transient period and before the vortex has been well formed, the linear growth rates, Îłv\gamma_v and ÎłÏ\gamma_{\rho}, vary with Dv{D_{v}} and Dρ{D_{\rho}} approximately in the following way, ln⁥γv=a−bDv\ln\gamma_{v}=a-bD_{v} and ÎłÏ=c+eln⁥Dρ(Dρ<DρE)\gamma_{\rho}=c+e\ln D_{\rho} ({D_{\rho}}<{D_{\rho}^{E}}), where aa, bb, cc and ee are fitting parameters and DρE{D_{\rho}^{E}} is the effective interaction width of density transition layer. When Dρ>DρE{D_{\rho}}>{D_{\rho}^{E}} the linear growth rate ÎłÏ\gamma_{\rho} does not vary significantly any more. One can use the hybrid effects of velocity and density transition layers to stabilize the KHI. Our numerical simulation results are in general agreement with the analytical results [L. F. Wang, \emph{et al.}, Phys. Plasma \textbf{17}, 042103 (2010)].Comment: Accepted for publication in PR

    Universal photonic processors in a glass-based femtosecond laser writing platform

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    Femtosecond laser writing (FLW) can open new perspectives on universal photonic processors (UPPs). We propose here two building blocks for the realization of FLW-UPPs and we show the preliminary results obtained on a 6-mode device
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