Sökning: "pulsations"

Visar resultat 16 - 20 av 42 avhandlingar innehållade ordet pulsations.

  1. 16. Time-accurate Turbulence Modeling of Swirling Flow for Hydropower Application

    Författare :Ardalan Javadi; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Hybrid RANS-LES; Swirling Flow; DES; Vortex Breakdown; Turbulence Modeling; Hydropower; LES;

    Sammanfattning : Hydraulic turbomachines have played a prominent role in the procurement of renewableenergy for more than a century. Embedded in the context of general technological progress,their design for efficiency and reliability has reached an outstanding level of quality. LÄS MER

  3. 17. Fetal Cardiac Function and Venous Circulation - Experiences with Velocity Vector Imaging

    Författare :Charlotte Dahlbäck; Urogynekologi och reproduktionsfarmakologi; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; pregnancy; fetus; strain; speckle tracking; cardiac function; umbilical vein; venous; ductus venosus; Doppler;

    Sammanfattning : Placental dysfunction resulting in intrauterine growth restriction (IUGR) is a common complication of pregnany and severe IUGR, with ensuing fetal hypoxia is an important cause of perinatal mortality and morbidity. Doppler studies of fetal and maternal vessels are routinely used for fetal surveillance and alterations in fetal venous blood flow has been demonstrated as a late sign of fetal compromise. LÄS MER

  4. 18. Linear and non-linear dynamics of non-autonomous flows

    Författare :J. Simon Kern; Dan S. Henningson; Ardeshir Hanifi; Peter J. Schmid; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Time-dependent flows; linear stability; non-linear dynamics; Floquet analysis; optimally time-dependent modes; Teknisk mekanik; Engineering Mechanics;

    Sammanfattning : Fluid flows subject to time-dependent external forces or boundary conditions are ubiquitous in biology and technical applications. Whether one considers birds flying by flapping their wings or the gust response of wind turbines, the flow is non-autonomous. LÄS MER

  5. 19. Wind Farm Configuration and Energy Efficiency Studies - Series DC versus AC Layouts

    Författare :Stefan Lundberg; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Sammanfattning : In this thesis, the design and control of a wind farm utilizing series-connected wind turbines with a DC output has been evaluated. The advantage is that a suitable DC voltage level, appropriate for transmission of the generated power directly, without using a large centralized DC/DC converter, can be obtained. LÄS MER

  7. 20. Photoplethysmographic heart and respiratory rate monitoring : instrument design and evaluation

    Författare :Håkan Ugnell; Linköpings universitet; []
    Nyckelord :MEDICINE; MEDICIN;

    Sammanfattning : A new optical heart and respiratory rate monitor utilising the photoplethysmographic (PPG) signal is presented.The PPG method, first developed in the 1930s, is based on the fact that incident light to the skin surface is absorbed, scattered and reflected in tissue and blood. LÄS MER