Sökning: "heat partitioning"

Visar resultat 6 - 10 av 21 avhandlingar innehållade orden heat partitioning.

1. 6. Evaporation and Heat-flux Aggregation in Heterogeneous Boreal Landscapes

   Författare :Tony Persson; Sven Halldin; Dimitris Melas; Deliang Chen; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Hydrology; land-surface processes; heterogeneity; surface fluxes; soil-water content; high latitudes; snow; lakes; climate; mesoscale model; NOPEX; WINTEX; Hydrologi; Hydrology; Hydrologi;

   Sammanfattning : The boreal forests represent 8 % of all forested areas on the earth and have a significant role in the control of greenhouse gases and an impact on global climate change. The main objective of this thesis is to increase the understanding of how evaporation and heat-flux processes in the boreal forest zone are affecting the regional and global climate. LÄS MER

3. 7. 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

4. 8. Increasing phase transformation rate in advanced high strength steel applications

   Författare :Farnoosh Forouzan; Esa Vuorinen; Frank Mücklich; Maria Santofimia Navarro; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Advanced high strength steel; Quenching and partitioning; welding; Engineering Materials; Materialteknik;

   Sammanfattning : The bainite transformation rate has been shown to increase by starting the heat treatment with partial martensite transformation after austenitization. Based on this fact, a process very similar to “Quenching and Partitioning” (Q&P) is used to produce a fine-grained complex microstructure of martensite, bainite and retained austenite with outstanding mechanical properties in a very short time. LÄS MER

5. 9. The fracture mechanisms in duplex stainless steels at sub-zero temperatures

   Författare :Johan Pilhagen; Pavel Korzhavy; Rolf Sandström; Kim Wallin; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Duplex stainless steel; Weldments; Delamination; Fracture toughness; Impact toughness; Cleavage fracture; Nickel;

   Sammanfattning : The aim of the thesis was to study the susceptibility for brittle failures and the fracture process of duplex stainless steels at sub-zero temperatures (°C). In the first part of the thesis plates of hot-rolled duplex stainless steel with various thicknesses were used to study the influence of delamination (also known as splits) on the fracture toughness. LÄS MER

7. 10. Surface energy exchange and land-atmosphere interactions of Arctic and subarctic tundra ecosystems under climate change

   Författare :Christian Stiegler; Institutionen för naturgeografi och ekosystemvetenskap; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Surface energy exchange; Arctic and subarctic tundra; climate change; permafrost; eddy covariance; snow cover; micrometeorology;

   Sammanfattning : The surface energy balance determines the functioning of any ecosystem on the Earth but is still poorly understood in Arctic and subarctic biomes. In a dynamic system, such as the Earth’s climate, any change in its characteristics modifies the exchange of energy, water, and greenhouse gases between the surface and the atmosphere. LÄS MER