Sökning: "Hans Andrén"

Visar resultat 1 - 5 av 7 avhandlingar innehållade orden Hans Andrén.

1. 1. Development of the Laitaure Delta, Swedish Lappland : A Study of Growth, Distributary Forms and Processes

   Författare :Hans Andrén; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Recent delta formation; hydraulic geometry; distributary forms and processes; X-ray radiography; Sarek; Lappland; Earth Science with specialization in Physical Geography; Geovetenskap med inriktning mot naturgeografi;

   Sammanfattning : Deltaic processes were studied on the Laitaure delta. Specific aims were to: analyse forms and processes in distributaries with regard to hydraulic geometry relationships; investigate the distribution of water into different distributaries; analyse the morphological development of the delta; and quantify the advance of the delta front. LÄS MER

3. 2. Toxicity of Inorganic Aluminium in Humic Streams

   Författare :Cecilia M. Andrén; Emil Rydin; Hans Borg; Ann-Kristin Eriksson Wiklund; Björn-Olav Rosseland; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Inorganic Al; toxicity; acidification; humic streams; Applied Environmental Science; tillämpad miljövetenskap;

   Sammanfattning : Aluminium (Al) has been recognised as a main toxic factor alongside pH in acidified water ecosystems. The toxic effect of Al has been attributed to inorganic Al (Ali), though there are few in situ studies in ambient humic waters which are the focus of this thesis. LÄS MER

4. 3. Effect of austenitising temperature and cooling rate on microstructures of hot-work tool steels

   Författare :María Teresa Coll Ferrari; Leif Karlsson; Hans-Olof Andrén; Högskolan Väst; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Tool steel; Heat Treatment; Austenitising Temperature; Large Tools; Tempering Carbides; Bainitic Microstructures; Production Technology; Produktionsteknik; Manufacturing and materials engineering; Produktions- och materialteknik;

   Sammanfattning : The average size of hot-work tools has gradually increased over the past years.This affects the effective temperature cycle tools experience during hardening,as large dimensions prevent uniform and rapid cooling, and thereby the resulting microstructures and properties. LÄS MER

5. 4. Powder-metallurgical processing and phase separation in ternary transition metal carbides

   Författare :Taoran Ma; Joakim Odqvist; Peter Hedström; Hans-Olof Andren; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Teknisk materialvetenskap; Materials Science and Engineering;

   Sammanfattning : Ternary transition metal cubic carbides have high hardness and are potential carbides in cemented carbide and cermet tools, as well as hard coatings used to improve metal cutting performance. In the present work, (Ti,Zr)C, (V,Nb)C, and (V,Ta)C ternary cubic carbides were synthesized using traditional powder-metallurgical methods. LÄS MER

7. 5. Modeling the Microstructure Evolution During and After Hot Working in Martensitic Steel

   Författare :Nima Safara Nosar; John Ågren; Göran Engberg; Hans-Olof Andrén; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Modeling; Martensitic steel; Carbides; Carbide size distribution; Carbide volume fraction; Carbide shape factor; Modellering; Martensitiskt stål; karbider; karbidstorleksfördelning; karbidvolymfraktion; karbidformfaktor; Teknisk materialvetenskap; Materials Science and Engineering;

   Sammanfattning : In this study, the goal is to predict the microstructure evolution during and after the hot working of a martensitic stainless steel with 13% chromium using a physically-based model in the form of a MATLAB toolbox. This model is based on dislocation density theory and consists of coupled sets of evolution equations for dislocation, vacancies, recovery, recrystallization, and grain growth. LÄS MER