Sökning: "carbon-rich"

Visar resultat 6 - 10 av 30 avhandlingar innehållade ordet carbon-rich.

  1. 6. Studies of the S-type AGB star W Aquilae : The circumstellar envelope and the fain companion

    Författare :Taissa Danilovich; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; stars: binaries: spectroscopic; circumstellar matter; stars: binaries: visual; stars: evolution; stars: mass-loss; stars: AGB and post-AGB; stars: individual: W Aql;

    Sammanfattning : Low- and intermediate-mass stars will all eventually enter the asymptotic giant branch (AGB) phase. AGB stars experience intense mass-loss, generating a significant fraction of the dust and molecular matter that enrichesthe ISM. AGB stars are also responsible for a the production of about half of all elements heavier than iron. LÄS MER

  3. 7. On the Winds of Carbon Stars and the Origin of Carbon : A Theoretical Study

    Författare :Lars Mattsson; Susanne Höfner; Nils Bergvall; Kjell Olofsson; Martin Groenewegen; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; AGB stars; carbon stars; mass loss; stellar winds; circumstellar matter; cosmic dust; stellar evolution; nucleosynthesis; galactic chemical evolution; Astronomy and astrophysics; Astronomi och astrofysik; Astronomy; Astronomi; Fysik; Physics;

    Sammanfattning : Carbon is the basis for life, as we know it, but its origin is still largely unclear. Carbon-rich Asymptotic Giant Branch (AGB) stars (carbon stars) play an important rôle in the cosmic matter cycle and may contribute most of the carbon in the Galaxy. LÄS MER

  4. 8. Debris disks from an astronomical and an astrobiological viewpoint

    Författare :Gianni Cataldi; Alexis Brandeker; Göran Olofsson; Eric Stempels; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; debris disks; planetary systems; exoplanets; astrobiology; circumstellar matter; biomarker; biosignature; extraterrestrial life; Astronomy; astronomi;

    Sammanfattning : In this licentiate thesis, I consider debris disks from an observational, astronomical viewpoint, but also discuss a potential astrobiological application. Debris disks are essentially disks of dust and rocks around main-sequence stars, analogue to the Kuiper- or the asteroid belt in our solar system. LÄS MER

  5. 9. Hydrology and water chemistry in a heterogeneous landscape : process-based modelling of coupled surface water and groundwater flow across contrasting boreal catchments

    Författare :Elin Jutebring Sterte; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Surface water and groundwater are connected, and the exchange between them is a vital part of a catchment’s hydrology. Along the flow paths through the catchment, biogeochemical processes can change the water’s chemical composition. LÄS MER

  7. 10. Effects on Machinability due to Microstructure Variations in Case Hardening Steel

    Författare :Karin Björkeborn; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Machinability; Short-term test; Microstructure; Pearlite Nodular Size; Case Hardening Steel; Chip breakability.;

    Sammanfattning : Typical products made of case hardening steel are transmission parts like gear wheels, pinions and crown wheels. Case hardening produces a carbon-rich surface and provides the parts with both enhanced hardness and fatigue life. LÄS MER