131 research outputs found

    Permeability and conductivity of platelet-reinforced membranes and composites

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    We present large scale simulations of the diffusion constant DD of a random composite consisting of aligned platelets with aspect ratio a/b>>1a/b>>1 in a matrix (with diffusion constant D0D_0) and find that D/D0=1/(1+c1x+c2x2)D/D_0 = 1/(1+ c_1 x + c_2 x^2), where x=avf/bx= a v_f/b and vfv_f is the platelet volume fraction. We demonstrate that for large aspect ratio platelets the pair term (x2x^2) dominates suggesting large property enhancements for these materials. However a small amount of face-to-face ordering of the platelets markedly degrades the efficiency of platelet reinforcement.Comment: RevTeX, 5 pages, 4 figures, submitted to PR

    Computational Simulations of Magnetic Particle Capture in Arterial Flows

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    The aim of Magnetic Drug Targeting (MDT) is to concentrate drugs, attached to magnetic particles, in a specific part of the human body by applying a magnetic field. Computational simulations are performed of blood flow and magnetic particle motion in a left coronary artery and a carotid artery, using the properties of presently available magnetic carriers and strong superconducting magnets (up to B ≈ 2 T). For simple tube geometries it is deduced theoretically that the particle capture efficiency scales as \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}ηMnp\eta \sim \sqrt{{Mn}_{\rm p}}\end{document}, with Mnp the characteristic ratio of the particle magnetization force and the drag force. This relation is found to hold quite well for the carotid artery. For the coronary artery, the presence of side branches and domain curvature causes deviations from this scaling rule, viz. η ∼ Mnpβ, with β > 1/2. The simulations demonstrate that approximately a quarter of the inserted 4 μm particles can be captured from the bloodstream of the left coronary artery, when the magnet is placed at a distance of 4.25 cm. When the same magnet is placed at a distance of 1 cm from a carotid artery, almost all of the inserted 4 μm particles are captured. The performed simulations, therefore, reveal significant potential for the application of MDT to the treatment of atherosclerosis

    Search for resonances decaying into photon pairs in 139 fb−1 of pp collisions at √s = 13 TeV with the ATLAS detector

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    Searches for new resonances in the diphoton final state, with spin 0 as predicted by theories with an extended Higgs sector and with spin 2 using a warped extra-dimension benchmark model, are presented using 139 fb−1 of √s = 13 TeV pp collision data collected by the ATLAS experiment at the LHC. No significant deviation from the Standard Model is observed and upper limits are placed on the production cross-section times branching ratio to two photons as a function of the resonance mass

    Measurement of the top-quark mass using a leptonic invariant mass in pp collisions at s√ = 13 TeV with the ATLAS detector

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    A measurement of the top-quark mass (mt) in the tt¯ → lepton + jets channel is presented, with an experimental technique which exploits semileptonic decays of b-hadrons produced in the top-quark decay chain. The distribution of the invariant mass mℓμ of the lepton, ℓ (with ℓ = e, μ), from the W-boson decay and the muon, μ, originating from the b-hadron decay is reconstructed, and a binned-template profile likelihood fit is performed to extract mt. The measurement is based on data corresponding to an integrated luminosity of 36.1 fb−1 of s√ = 13 TeV pp collisions provided by the Large Hadron Collider and recorded by the ATLAS detector. The measured value of the top-quark mass is mt = 174.41 ± 0.39 (stat.) ± 0.66 (syst.) ± 0.25 (recoil) GeV, where the third uncertainty arises from changing the PYTHIA8 parton shower gluon-recoil scheme, used in top-quark decays, to a recently developed setup

    Automatic Generation of Virtual Computer Rooms on the Internet Using X3D

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    7th International Conference on Computational Science (ICCS 2007) -- MAY 27-30, 2007 -- Beijing, PEOPLES R CHINAWOS: 000247062900022In this paper, some natural links between virtual reality and interactive 3D computer graphics are specified and Web3D technologies especially VRML and X3D are briefly introduced. Web-based tool which is called EasyLab3D was designed and implemented using X3D. This web-based tool is used to generate automatically 3D virtual computer rooms that can be navigated in. It is important for introduction of departments, companies and organizations which have computer laboratories and for planning new computer rooms. As a result, state-of-the art technologies and methods in development of automatic 3D scene and model generation tools are discussed.Chinese Acad Sci, Res Ctr Data Technol & Knowledge Econ, AMID, Springer, World Sci Publishing, Univ Nebraska, CAS, Grad Univ, Chinese Acad Sci, Inst Policy & Management, Univ Amsterda
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