Sökning: "boundary cap"

Visar resultat 11 - 15 av 17 avhandlingar innehållade orden boundary cap.

  1. 11. Multi-Spacecraft Observations of the Auroral Acceleration Region

    Författare :Soheil Sadeghi; Göran T. Marklund; Andris Vaivads; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : The two major agents for producing aurora are generally believed to be the quasi-static parallel electric fields, accelerating electrons in the auroral acceleration region (AAR), and Alfvén waves. The Cluster spacecraft quartet has made multi-spacecraft measurements in the AAR possible for the first time. LÄS MER

  3. 12. Cluster in situ studies of the auroral acceleration region

    Författare :Bin Li; Göran Marklund; Stein Haaland; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Cluster; Aurora acceleration region; Physics; Fysik;

    Sammanfattning : This thesis addresses a central topic in auroral physics, namely particle accelerationproducing intense aurora as well as energetic plasma outflow. Cluster satellitemeasurements of electric and magnetic fields, electrons and ions, collected across auroralfield lines, are used to study various aspects of the quasi-static auroral accelerationregion (AAR), its relation to the auroral density cavity, and the relative role of quasistaticand Alfvénic acceleration for producing aurora. LÄS MER

  4. 13. Modelling and simulation of powder pressing with consideration of friction

    Författare :Bengt Wikman; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Hållfasthetslära; Solid Mechanics; Datorstödd maskinkonstruktion; Computer Aided Design;

    Sammanfattning : Finite element modelling and simulation of the powder pressing process can be used in the rational development of powder metallurgy (PM) components. Many of the nonlinear finite element (FE) codes available today can be used for powder pressing simulations. LÄS MER

  5. 14. Neural crest in development and repair

    Författare :Jorge Benjamín Aquino; Karolinska Institutet; Karolinska Institutet; []
    Nyckelord :;

    Sammanfattning : This thesis is focused on several aspects of neural crest biology, largely related to two main issues: 1) understanding its mechanisms of migration and 2) analyzing the potential of neural crest stem cells or their derivatives for nervous system repair. If repair is the aim, knowledge of both timing and events leading to axonal degeneration is required in order to block it and/or increase regeneration outcome. LÄS MER

  7. 15. Auditory organotypic cultures and progenitor cell implantation

    Författare :Andreas Kaiser; Karolinska Institutet; Karolinska Institutet; []
    Nyckelord :;

    Sammanfattning : According to the WHO, about 5 % of the world’s population suffers from disabling hearing loss. In people above the age of 65 the number is more than 30 %. Common effects of this condition are poor speech discrimination and impaired communication abilities. Patient surveys show that hearing loss often leads to a diminished quality of life. LÄS MER