Sökning: "accretion"

Visar resultat 1 - 5 av 46 uppsatser innehållade ordet accretion.

  1. 1. Archaeologic inspection of the Milky Way using vibrations of a fossil : Seismic, spectroscopic and kinematic characterization of a binary metal-poor Halo star

    Kandidat-uppsats, Uppsala universitet/Observationell astrofysik

    Författare :Amanda Byström; [2020]
    Nyckelord :Milky Way; Halo; galactic archaeology; asteroseismology; binary star; CEMP stars; CEMP-r s stars; stellar age; stellar mass; chemical abundance pattern; Gaia-Enceladus; Gaia-Sausage; Sequoia; spectroscopy; metal-poor;

    Sammanfattning : The Milky Way has undergone several mergers with other galaxies during its lifetime. The mergers have been identified via stellar debris in the Halo of the Milky Way. The practice of mapping these mergers is called galactic archaeology. To perform this archaeologic inspection, three stellar features must be mapped: chemistry, kinematics and age. LÄS MER

  2. 2. Lyman Continuum Radiation from Intermediate-Mass Black Holes : An Estimation of the Contribution of LyC Radiation from IMBHs in z~3 Galaxies

    Kandidat-uppsats, Uppsala universitet/Observationell astrofysik

    Författare :Marika Ljungberg; [2020]
    Nyckelord :intermediate-mass black holes; cosmic reionization; high-redshift galaxies;

    Sammanfattning : This thesis concerns the cosmic reionization of the intergalactic medium in the high redshift universe and, in particular, is a first approach to examine what role intermediate mass black holes (IMBHs) play in this cosmic age. Unexpectedly high values of hydrogen ionizing radiation, compared to current models, have been reported from galaxies at redshift ~3 (used as stand-ins for galaxies at the age of reionization), and thus these models need revision, potentially by adding effects of IMBH content in the galaxies. LÄS MER

  3. 3. Defining, analyzing and determining power losses - due to icing on wind turbine blades

    Uppsats för yrkesexamina på avancerad nivå, Mälardalens högskola/Akademin för ekonomi, samhälle och teknik

    Författare :Zandra Canovas Lotthagen; [2020]
    Nyckelord :Wind Power; De-icing; Defining; Ice losses; Task19; Temperature threshold; Power curve; Big Data;

    Sammanfattning : The wind power industry is one of the fastest-growing renewable energy industries in the world. Since more energy can be extracted from wind when the density is higher, a lot of the investments made in the wind power industry are made in cold climates. But with cold climates come harsh weather conditions such as icing. LÄS MER

  4. 4. Original: X-ray Spectral Analysis of a Serendipitously Observed Active Galactic Nucleus

    Kandidat-uppsats, KTH/Skolan för teknikvetenskap (SCI); KTH/Skolan för teknikvetenskap (SCI)

    Författare :Teodor Elmfeldt; Filip af Malmborg; [2020]
    Nyckelord :;

    Sammanfattning : An active galactic nucleus (AGN) is a region in the center of a galaxy with a supermassive black hole continuosly accreting material. This accretion gives rise to large amounts of radiation across the whole electromagnetic spectrum, and largely affects the regions around the AGN and the evolution of the whole galaxy. LÄS MER

  5. 5. Analysis of Customer Behaviours on Customer Reviews and Ratings

    Kandidat-uppsats, KTH/Skolan för industriell teknik och management (ITM); KTH/Skolan för industriell teknik och management (ITM)

    Författare :Alkim Yetis; Erkut Kavak; [2020]
    Nyckelord :Customer reviews; e-commerce; customer behaviour; fashion industry; genderbased products; text-typed comments; content analysis; Kundrecensioner; e-handeln; kundbeteende; modebranschen; könsinriktade produkter; textskrivna kommentarer; innehållsanal;

    Sammanfattning : With the rapid accretion of online shopping, online customer reviews have become a very essential source. An interpretation of this essential source is not fulfilled with every aspect since online customer reviews consists of unstructured information. LÄS MER