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Visar resultat 1 - 5 av 379 avhandlingar som matchar ovanstående sökkriterier.

  1. 1. Microstructure Evaluation and Wear-Resistant Properties of Ti-alloyed Hypereutectic High Chromium Cast Iron

    Författare :Qiang Liu; Pär Jönsson; Keiji Nakajima; Niels Skat Tiedje; KTH; []
    Nyckelord :High Chromium Cast Iron; cooling rate; Ti addition; M7C3; TiC; carbides size distributions; volume fraction; heat treatment; microstructure; mechanical properties; wear resistance; statistics of extreme values SEV ; maximum carbides size.;

    Sammanfattning : High chromium cast iron (HCCI) is considered as one of the most useful wear resistance materials and their usage are widely spread in industry. The mechanical properties of HCCI mainly depend on type, size, number, morphology of hard carbides and the matrix structure (γ or α). LÄS MER

  3. 2. The high Arctic summer aerosol : Size, chemical composition, morphology and evolution over the pack-ice

    Författare :Evelyne Hamacher-Barth; Caroline Leck; Stephan Weinbruch; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Arctic; aerosol; marine gel; electron microscopy; EDX-spectroscopy; chemical composition; morphology; size distribution; atmosfärvetenskap och oceanografi; Atmospheric Sciences and Oceanography;

    Sammanfattning : Aerosol particles, especially in the high Arctic are still not very well represented in climate models. Particle size and number concentrations are strongly under-predicted and temporal variations of aerosol composition and size are still not very well understood, mainly due to the sparsity of observations. LÄS MER

  4. 3. Three Dimensional Determinations of Inclusions in Ferroalloys and Steel Samples

    Författare :Yanyan Bi; Andrey Karasev; Chris Pistorius; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Three dimensional; Ferroalloy; Inclusion; Spinel inclusion; T hermodynamic calculation; REM clusters; Formation mechanism; Statistical analysis; Maximum size;

    Sammanfattning : As the requirements on material properties increase, there has been a demand on an additional knowledge on the effect of impurities in the ferroalloyson the steel cleanness. Thus, the number, morphology, size and composition of inclusions in sixdifferent ferroalloys (FeTi, FeNb, FeSi,SiMn, LC and HC FeCr) were investigatedin this study. LÄS MER

  5. 4. Lower Bounds and Trade-offs in Proof Complexity

    Författare :Susanna F. de Rezende; Jakob Nordström; Amit Chakrabarti; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Proof complexity; trade-offs; lower bounds; size; length; space; Computer Science; Datalogi;

    Sammanfattning : Propositional proof complexity is a field in theoretical computer science that analyses the resources needed to prove statements. In this thesis, we are concerned about the length of proofs and trade-offs between different resources, such as length and space. LÄS MER

  7. 5. Invasion of top and intermediate consumers in a size structured fish community

    Författare :Per Ask; Lennart Persson; Daniel E Schindler; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Invasion; intraguild predation; size-structure; cannibalism; climate; temperature; Arctic char; ninespine stickleback; Freshwater ecology; Limnisk ekologi; biology; biologi;

    Sammanfattning : In this thesis I have investigated the effects of invading top and intermediate consumers in a size-structured fish community, using a combination of field studies, a lake invasion experiment and smaller scale pond and aquaria experiments. The lake invasion experiment was based on introductions of an intermediate consumer, ninespine stickleback (Pungitius pungitius L. LÄS MER