Sökning: "pulsation"

Visar resultat 1 - 5 av 31 avhandlingar innehållade ordet pulsation.

  1. 1. Investigation of jet pulsation effects on near-nozzle mixing and entrainment

    Författare :Alexander Nygård; Laszlo Fuchs; Lisa Prahl Wittberg; Mireia Altimira; Xandra Margot; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Sprays; Nozzle; Mixing; Pulsation; Engineering Mechanics; Teknisk mekanik;

    Sammanfattning : Turbulent jet flows are very common in engineering applications. One example is that of fuel injection in internal combustion engines, which is closely related to the combustion process. Because of the widespread use, the resulting emissions of such engines have a significant impact on human health and the environment. LÄS MER

  3. 2. Ultrasound as predictor of perinatal outcome

    Författare :Gisela Ghosh; gynekologisk och prenatal ultraljudsdiagnostik Obstetrisk; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Doppler; Ultrasound; fetus; amniotic fluid index; nuchal cord; uterine artery; umbilical vein; fetal growth restriction; umbilical artery; pulsation; pregnancy;

    Sammanfattning : The aim of the work described in this thesis was to evaluate the value of ultrasound examinations of the amniotic fluid, umbilical cord and blood flow velocity waveform of the fetal and placental vessels as predictors of the perinatal outcome. In the first study, the amniotic fluid index (AFI) measured on admission to the labour ward was evaluated in low-risk pregnancies. LÄS MER

  4. 3. Experimental study of turbulent flows through pipe bends

    Författare :Athanasia Kalpakli; P. Henrik Alfredsson; Ramis Örlü; Christoph Brücker; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Turbulent flow; swirl; pulsation; pipe bend; hot-wire anemometry; cold-wire anemometry; laser Doppler velocimetry; stereoscopic particle image velocimetry.;

    Sammanfattning : This thesis deals with turbulent flows in 90 degree curved pipes of circular cross-section. The flow cases investigated experimentally are turbulent flow with and without an additional motion, swirling or pulsating, superposed on the primary flow. LÄS MER

  5. 4. Stellar Winds of Cool Giants : Investigating the Mass-Loss Mechanism of AGB Stars

    Författare :Sofie Liljegren; Susanne Höfner; Kjell Eriksson; Bernd Freytag; Hans Olofsson; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; late-type stars; AGB stars; stellar winds; stellar atmospheres; dust; stellar pulsation; hydrodynamics; radiative transfer;

    Sammanfattning : Asymptotic giant branch (AGB) stars are luminous cool giants of low to intermediate mass that are strongly pulsating and non-spherical, with heavy mass loss through a stellar wind. The mass loss makes these stars important for galactic chemistry, as the wind enriches the interstellar medium with new elements and dust, and it determines the final fate of these stars. LÄS MER

  7. 5. Inside Pulsating White Dwarfs: Clues from time-resolved spectroscopy

    Författare :Rubina Kotak; Astronomi - Genomgår omorganisation; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; pulsating white dwarfs; convection; asteroseismology; Astronomi; Astronomy; spectroscopy; Fysicumarkivet A:2002:Kotak;

    Sammanfattning : Several analyses using time-resolved optical spectrocopy of pulsating white dwarfs are presented. The data have been put to a number of uses. First, line-of-sight velocities associated with the pulsations have been measured in three hydrogen-atmosphere white dwarfs (DAVs), bringing the total number of such measurements up to five. LÄS MER