Search for dissertations about: "Critical thermal effects"

Showing result 1 - 5 of 69 swedish dissertations containing the words Critical thermal effects.

  1. 1. Thermal conductivity of wide and ultra-wide bandgap semiconductors

    Author : Dat Tran; Plamen Paskov; Vanya Darakchieva; Martin Kuball; Linköpings universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; III-nitrides; β-Ga2O3; Thermal conductivity; Thermal transport;

    Abstract : This PhD thesis presents experimental and theoretical studies of the thermal conductivity of wide and ultra-wide bandgap semiconductors including GaN, AlN, β-Ga2O3 binary compounds, and AlxGa1−xN, ScxAl1−xN, YxAl1−xN ternary alloys. Thermal conductivity measurements are conducted using the transient thermoreflectance (TTR) technique and the results are interpreted using analytical models based on the solution of the Boltzmann transport equation (BTE) within the relaxation time approximation (RTA). READ MORE

  2. 2. Thermal shock and thermal fatigue in ceramic materials

    Author : Tomas Andersson; KTH; []
    Keywords : ;

    Abstract : This thesis concerns thermal stress fracture in ceramicmaterials. The work describes a new technique for determiningthe thermal shock resistance of brittle materials as well asexperimental results and thermal stress simulations. READ MORE

  3. 3. Failure of thermal barrier coatings under thermal and mechanical fatigue loading : microstructural observations and modelling aspects

    Author : Håkan Brodin; Anette M. Karlsson; Linköpings universitet; []
    Keywords : thermal barrier coating; TBC; delamination; crack initiation; crack propagation; crack growth; oxidation; alumina; spinel; MCrAIY; diffusion; fatigue; modelling; modeling; degradation; TECHNOLOGY; TEKNIKVETENSKAP;

    Abstract : Industrial and air-borne gas turbine hot components suffer from creep, oxidation, corrosion and microstructural degradation if not shielded from the hot and aggressive combustion gases. Two major strategies commercially available are adopted; film cooling by pressurised air and application of protective coatings. READ MORE

  4. 4. Optical manipulation and heating of gold nanoparticles near interfaces

    Author : Daniel Andrén; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; LSPR spectroscopy; particle-surface separation distance; thermal reshaping; TIRM; nanomotor; plasmonics; photothermal effects; Brownian dynamics; gold nanorod; optical tweezers;

    Abstract : By focusing laser light to small volumes, its momentum can be used to trap and manipulate objects in the size range from cells down to single atoms. Devices using this effect are called optical tweezers, and have found use in measuring and applying minuscule forces and torques, contributed to deepening our knowledge of molecular motors, unraveling the mechanics of cells and DNA, and better understand statistical mechanics and hydrodynamic interactions at the nanoscale. READ MORE

  5. 5. Reflector Optimization for Low Concentration Photovoltaic-Thermal Solar Collectors

    Author : Diogo Cabral; Hans Wigö; Björn O. Karlsson; Maria João Carvalho; Högskolan i Gävle; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Photovoltaic-thermal collector; experimental assessment; collector performance assessment; optical efficiency; concentrating PVT solar collector; ray tracing; Fotovoltaisk-termisk kollektor; experimentell utvärdering; prestandautvärdering; optisk effektivitet; koncentrerande PVT-solfångare; strålgångsanalys;

    Abstract : The alarming new global warming and increasing awareness related to climate change (mainly due to the high emissions of carbon dioxide) in recent decades linked all nations into a common cause, which requires ambitious efforts to combat climate change by adapting energy systems to its effects.The knowledge gain presented in this dissertation establishes the foundations for the development of a more efficient concentrating photovoltaic-thermal (PVT) solar collector. READ MORE