Sökning: "Comets"

Visar resultat 16 - 20 av 20 avhandlingar innehållade ordet Comets.

  1. 16. Radio meteors above the Arctic Circle : radiants, orbits and estimated magnitudes

    Författare :Csilla Szasz; Asta Pellinen-Wannberg; Noah Brosch; Umeå universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; meteors; meteoroids; dust; meteor radiants; meteoroid orbits; sporadic sources; radar; meteorradianter; meteoroidbanor; sporadiska källområden; radar; meteorer; meteoroider; interplanetärs stoft; Space engineering; Rymdteknik;

    Sammanfattning : This thesis presents results based on data collected with the 930 MHz EISCAT UHF radar system and three SKiYMet specular meteor radars. It describes in detail a method for meteoroid orbit calculation. The EISCAT UHF system comprises three identical 32 m parabolic antennae: one high-power transmitter/receiver and two remote receivers. LÄS MER

  3. 17. Measurement of primary DNA damage in individual cells from humans and mice using the alkaline single cell gel electrophoresis assay

    Författare :Hamid Vaghef; Uppsala universitet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Pharmaceutical biosciences; Farmaceutisk biovetenskap; Biopharmacy; Biofarmaci; arbets- och miljömedicin; Occupational and Environmental Medicine;

    Sammanfattning : Primary DNA damage is considered to be an important step in the development of tumours and itmay also serve as a biomarker of genotoxic stress. Measurement of DNA strand breaks in peripherallymphocytes can yield useful information about the suitability of these cells for biomonitoring purposesand subsequently risk assessment. LÄS MER

  4. 18. Laser Interaction with Minerals Common on Asteroids

    Författare :Niklas Anthony; Mikael Granvik; Christina Wanhainen; Olle Norberg; Christopher Dreyer; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Onboard space systems; Rymdtekniska system;

    Sammanfattning : Asteroids are worth studying for three reasons: planetary protection, industrial applications, and scientific knowledge. It is critical we develop technologies capable of diverting objects on collision courses with our planet. LÄS MER

  5. 19. Debris disks and the search for life in the universe

    Författare :Gianni Cataldi; Alexis Brandeker; Jean-Charles Augereau; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; debris disks; astrobiology; Astronomy; astronomi;

    Sammanfattning : Circumstellar debris disks are the extrasolar analogues of the asteroid belt and the Kuiper belt. These disks consist of comets and leftover planetesimals that continuously collide to produce copious amounts of circumstellar dust that can be observed as infrared excess or in resolved imaging. LÄS MER

  7. 20. Thin water and ice films on minerals : a molecular level study

    Författare :Merve Yeşilbaş; Jean-François Boily; Johannes Messinger; Grégory Lefèvre; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; water; ice; cryosalt; minerals; rocks; atmosphere; Dynamic Vapour Sorption; FTIR; cryo-FESEM; fysikalisk kemi; Physical Chemistry;

    Sammanfattning : Minerals in Earth’s crust and suspended in the atmosphere form water or ice films as thin as a few nanometers to as thick as a few micrometers, and beyond. Mineral-bound water and ice films in terrestrial systems (e.g. LÄS MER