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Visar resultat 1 - 5 av 182 avhandlingar som matchar ovanstående sökkriterier.

  1. 1. Modelling and simulation of turbulence subject to system rotation

    Författare :Olof Grundestam; Arne Johansson; Sharath Girimaji; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Direct numerical simulations; least-squares method; turbulence model; nonlinear modelling; system rotation; streamline curvature; high-lift aerodynamics; Fluid mechanics; Strömningsmekanik;

    Sammanfattning : Simulation and modelling of turbulent flows under influence of streamline curvature and system rotation have been considered. Direct numerical simulations have been performed for fully developed rotating turbulent channel flow using a pseudo-spectral code. The rotation numbers considered are larger than unity. LÄS MER

  3. 2. On the Einstein-Vlasov system: Stationary Solutions and Small Data Solutions with Charged and Massless Particles

    Författare :Maximilian Thaller; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Static Solutions; Vector Field Method; non-linear wave equation; massless Einstein-Vlasov system; General Relativity; Conformal Einstein Field Equations; Minkowski stability; Vlasov matter; symmetric hyperbolic system; Einstein-Vlasov-Maxwell system;

    Sammanfattning : The Vlasov matter model describes an ensemble of collisionless particles moving through space-time. These particles interact via the gravitational field which they create collectively. In the framework of General Relativity this gravitational field is described by space-time curvature. LÄS MER

  4. 3. Design of Electro-Hydraulic Energy Converters : With Focus on Integrated Designs and Valve Plate Rotation

    Författare :Thomas Heeger; Liselott Ericson; Andreas Johansson; Linköpings universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Sammanfattning : In mobile working machines, there is a trend towards replacing combustion engines by electric machines to reduce their carbon footprint. This provides several advantages and challenges for the hydraulic system. The low efficiency of conventional hydraulic systems is no longer acceptable due to the volume and cost of batteries. LÄS MER

  5. 4. Neuroprotective and regenerative actions of GDNF and neurturin on nigral dopamine neurons in rat models of Parkinson’s disease – Prospects for clinical use of neurotrophic factors in neurodegenerative disorders

    Författare :Carl Rosenblad; Neurobiologi; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; neurophysiology; neuropsychology; Neurology; striatum; substantia nigra; dopamine; GDNF; neurturin; sprouting; neuroprotection; forelimb akinesia; rotation; tyrosine hydroxylase; transplantation; Neurologi; neuropsykologi; neurofysiologi;

    Sammanfattning : Parkinson’s disease is characterized by progressive degeneration of the nigrostriatal dopamine system, which results in tremor, rigidity, akinesia and postural abnormalities. New therapeutic strategies are aimed at halting the neurodegenerative process or restoring the system by transplantation of fetal dopamine neurons. LÄS MER

  7. 5. The Dynamical Spin Vector Evolution of the Asteroids

    Författare :Erik Skoglöv; Karri Muinonen; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Astronomy; asteroids; Eros; Ceres; Vesta; dynamics; rotation; rotational dynamics; orbits; resonances; Astronomi; Astronomy and astrophysics; Astronomi och astrofysik; astronomi; Astronomy;

    Sammanfattning : The dynamical evolution of the spin axis direction due to gravitational and thermal factors is examined. It is found that the spin axis variations generally are regular and relatively small for the bodies in the asteroid main belt. There are also reasons to believe that this is the case for minor objects beyond the main belt. LÄS MER