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Visar resultat 1 - 5 av 11 avhandlingar som matchar ovanstående sökkriterier.

  1. 1. Genetic and molecular regulation of epithelial tube morphogenesis

    Författare :Anna Tonning; Göteborgs universitet; []
    Nyckelord :epithelial tube morphogenesis; trachea; Drosophila; chitin; chitin synthase; apical extracellular matrix; paracellular diffusion barrier; tube expansion; septate junctions;

    Sammanfattning : Networks of epithelial tubes, such as the vertebrate lung, kidney and vascular system, enable transport of gases and nutrients to all tissues in the body. These tubes are built up by a single layer of polarized epithelial cells, with the apical membrane facing the lumen. LÄS MER

  3. 2. Modelling of IC-Engine Intake Noise

    Författare :Magnus Knutsson; Mats Åbom; Yves Auregán; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; IC-engine; intake noise; gas dynamics; linear source data; frequency domain; 2-port; losses; air cleaner unit; filter paper; flow; FEM; BEM; charge air cooler; narrow tube; Acoustics; Akustik;

    Sammanfattning : Shorter product development cycles, densely packed engine compartments and intensified noiselegislation increase the need for accurate predictions of IC-engine air intake noise at earlystages. The urgent focus on the increasing CO2 emissions and the efficiency of IC-engines, aswell as new techniques such as homogeneous charge compression ignition (HCCI) mightworsen the noise situation. LÄS MER

  4. 3. Frequency Domain Linearized Navier-Stokes Equations Methodology for Aero-Acoustic and Thermoacoustic Simulations

    Författare :Wei Na; Gunilla Efraimsson; Susann Boij; Martinez Lera Paula; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Linearized Navier-Stokes Equations; frequency domain; fluid equivalent model; hybrid liner; thermoacoustic instabilities; Rijke-tube; Engineering Mechanics; Teknisk mekanik;

    Sammanfattning : The first part of the thesis focuses on developing a numerical methodology to simulate the acoustic properties of a hybrid liner consisting of a perforated plate, a porous layer and a Helmholtz cavity. Liners are always a standard way to reduce noise in today’s aeroengines, e.g. LÄS MER

  5. 4. Modeling a carbon-nanotube-based nanoelectromechanical relay

    Författare :Magnus Jonsson; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; surface forces; NEMS; carbon nanotubes; dissipation; nanorelay; mechanical resonances; stiction; high frequency applications; Nanoelectromechanical systems; field emission; tunable resonances;

    Sammanfattning : We have theoretically investigated the properties of a three-terminal carbon-nanotube-based nanoelectromechanical relay. The system operationis based on an coupling between electrical and mechanical degrees of freedom which is a typical characteristic of a NEMS device. LÄS MER

  7. 5. Mathematical modelling of flow through thin curved pipes with application to hemodynamics

    Författare :Arpan Ghosh; Vladimir Kozlov; Matts Karlsson; David Rule; Grigory Panasenko; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : The problem of mathematical modelling of incompressible flows with low velocities through narrow curvilinear pipes is addressed in this thesis. The main motivation for this modelling task is to eventually model the human circulatory system in a simple way that can facilitate the medical practitioners to efficiently diagnose any abnormality in the system. LÄS MER