Sökning: "Björgvin Hjörvarsson"

Visar resultat 11 - 15 av 33 avhandlingar innehållade orden Björgvin Hjörvarsson.

1. 11. Synthesis and Characterisation of Potential Hydrogen Storage Materials

   Författare :Emil Johansson; Björgvin Hjörvarsson; Astrid Pundt; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physics; Hydrogen; adsorption; absorption; thermodynamics; thin films; carbon nanostructures; Fysik; Physics; Fysik;

   Sammanfattning : The dissociative and non-dissociative hydrogen uptake in carbon nanostructures and metallic films were investigated by measurements and analysis of solubility isotherms. The total, non-dissociative, uptake for multi-walled nano-barrels and amorphous nanoporous carbon was determined to be 6.2 and 4.2 wt. LÄS MER

3. 12. Designing metallic glasses : Alloying, properties, and degrees of freedom

   Författare :Maciej Kaplan; Björgvin Hjörvarsson; Gunnar Pálsson; Jochen Schneider; Susanne Norgren; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; amorphous alloys; enthalpy of mixing; glass formation; thermal stability; thermodynamics; mechanical properties; corrosion resistance; hydrogen;

   Sammanfattning : The present design rules for metallic glasses with respect to glass formation, thermal stability (resistance to crystallisation), and material properties can still be improved. A main design rule is to use thermodynamic calculations to determine the composition of eutectic points in the phase space. LÄS MER

4. 13. Uncovering Magnetic Order in Nanostructured Disordered Materials : A Study of Amorphous Magnetic Layered Structures

   Författare :Panagiotis Korelis; Björgvin Hjörvarsson; Gabriella Andersson; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Amorphous Materials; Magnetism; Amorphous Magnetism; Magnetic Measurements; Thin Films; Multilayers; Thin Film Deposition; Sputtering; FeZr Alloys; AlZr Alloys; X-ray Diffraction; Rutherford Backscattering Spectrometry; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

   Sammanfattning : The scope of this thesis is the study of the interplay between structure and magnetism in amorphous materials. The investigations focus on the growth of amorphous layers and the study of the influence of structural disorder and reduced physical extension on the magnetic properties of thin films and multilayers. LÄS MER

5. 14. Amorphous, Nanocrystalline, Single Crystalline: Morphology of Magnetic Thin Films and Multilayers

   Författare :Andreas Liebig; Björgvin Hjörvarsson; Gabriella Andersson; Frank Klose; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physics; Multilayer; Superlattice; X-ray diffraction; X-ray reflectometry; electron diffraction; Rutherford backscattering spectrometry; Interdiffusion; thin film growth; transmission electron microscopy; Epitaxial growth; Fysik; Physics; Fysik;

   Sammanfattning : Properties of magnetic thin film devices cannot be understood without detailed knowledge of their structure. For this purpose, a variety of thin film and multilayer systems have been studied. LÄS MER

7. 15. Tailoring structure and morphology during additive manufacturing of metallic components

   Författare :Jithin James Marattukalam; Björgvin Hjörvarsson; Ulf Jansson; Martin Sahlberg; Lars Nyborg; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Selective laser melting; process parameters; scanning methodologies; AMLOYZR01; bulk metallic glass; 316L SS; grain orientation;

   Sammanfattning : The work described in this thesis explores the use of laser process parameters to functionalize the material properties by the control of microstructure and optimization of morphology in components by selective laser melting. The microstructure in amorphous and crystalline metallic alloy systems is influenced by changing the laser power density and scanning strategies respectively. LÄS MER