Sökning: "solar system: formation"

Visar resultat 11 - 15 av 67 avhandlingar innehållade orden solar system: formation.

1. 11. From meteors to space safety : dynamical models and radar measurements of space objects

   Författare :Daniel Kastinen; Johan Kero; Asta Pellinen-Wannberg; Mats Holmström; Detlef Koschny; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Meteors; meteor shower; atmosphere; meteoroids; meteoroid stream; small-body dynamics; solar system; comets; asteroids; near-Earth objects; space safety; space debris; radar; MU; EISCAT;

   Sammanfattning : Every day the Earth's atmosphere is bombarded by 10-200 metric tons of dust-sized particles and larger pieces of material from space called meteoroids. Dust and meteoroids come from parent bodies such as comets and asteroids, which are remnants from the formation of the solar system. LÄS MER

3. 12. Origin of solar surface activity and sunspots

   Författare :SARAH JABBARI; AXEL BRANDENBURG; Vasilis Archontis; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Sun-Solar activity-Sunspots; teoretisk astrofysik; Theoretical Astrophysics;

   Sammanfattning : In the last few years, there has been significant progress in the development of a new model for explaining magnetic flux concentrations, by invoking the negative effective magnetic pressure instability (NEMPI) in a highly stratified turbulent plasma. According to this model, the suppression of the turbulent pressure by a large-scale magnetic field leads to a negative contribution of turbulence to the effective magnetic pressure (the sum of non-turbulent and turbulent contributions). LÄS MER

4. 13. Studies of Semiconductors Modified with Nanoscale Light Absorbers for Solar Cell Application

   Författare :Boriss Mahrov; Hans Siegbahn; Anders Hagfeldt; Håkan Rensmo; Gerrit Boschloo; Gary Hodes; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physics; photoelectron spectroscopy; dye-sensitized; solar cells; inorganic light absorber; nanostructure; mesoporous; photovoltaic devices; Fysik; Physics; Fysik;

   Sammanfattning : Recently, materials such as hole conductors (CuI, CuSCN) and light absorbers (Ru-complexes, CuInS2) have been actively investigated for application in nanocrystalline solar cells. In this thesis combinations of these materials have been studied. LÄS MER

5. 14. Secondary Interactions in Symmetric Double Bond Formation Catalysed by Molecular Ruthenium Complexes

   Författare :Oleksandr Kravchenko; Licheng Sun; Roger Alberto; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; homogeneous catalysis; transition metal catalysis; ruthenium catalyst; olefin metathesis; dynamic covalent chemistry; water oxidation; solar fuels; Ru-bda; secondary interactions; hydrophobic interactions; π-π stacking; homogen katalys; övergångsmetallkatalys; rutheniumkatalysator; olefinmetates; dynamisk kovalent kemi; vattenoxidation; solbränslen; Ru-bda; sekundära interaktioner; hydrofoba interaktioner; π-π stapling; Kemi; Chemistry;

   Sammanfattning : Chemistry has a tremendous impact on everyone’s life, although society does not always realize its power and ubiquity. In recent years, improved economy and sustainability of chemical processes has become a worldwide priority. LÄS MER

7. 15. Solar Assisted Pervaporation (SAP) : A process using membrane pouches and solar energy for the dehydration and preservation of fruit juices in rural and remote areas

   Författare :Randi Phinney; Avdelningen för livsmedel och läkemedel; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; membrane; pervaporation; fruit preservation; solar drying; heat and mass transfer; coupling effects;

   Sammanfattning : Drying has been used for thousands of years to preserve foods. One of the first methods used was open air sun drying which exposes foods directly to solar radiation and ambient air. This method is still used today around the world but it remains underdeveloped on the small-scale for two main reasons. LÄS MER