Search for dissertations about: "conductivity"

Showing result 6 - 10 of 894 swedish dissertations containing the word conductivity.

  2. 6. On Thermal Conductivity and Strength in Compacted Graphite Irons : Influence of Temperature and Microstructure

    Author : Martin Selin; Ingvar L. Svensson; Attila Diószegi; Steve Dawson; Jönköping University; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Compacted Graphite Iron; Thermal Conductivity; Mechanical Properties; Hardness; Microstructure; Plastic Deformation; Hollomon Equation; Elevated Temperature; Materials science; Teknisk materialvetenskap;

    Abstract : Thermal conductivity, hardness and strength are all highly important material properties, affecting the performance and life expectancy of components operating at elevated temperatures. The main purpose of this work has been to increase the knowledge and understanding concerning how mechanical and physical properties are affected by temperature and microstructure in compacted graphite irons. READ MORE

  4. 7. 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

  5. 8. Thermal Conductivity of Materials under Conditions of Planetary Interiors

    Author : Zuzana Konôpková; Peter Lazor; Vitali Prakapenka; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; iron; high pressures-high temperatures; thermal conductivity; diamond anvil cell; laser-heating; planetary cores; Earth sciences; Geovetenskap;

    Abstract : The presented thesis focuses on study of transport and thermoelastic properties of materials under conditions of planetary interiors by means of high-pressure experimental tools and finite element modeling, and their role in the dynamics and states of cores of terrestrial planets. Experiments in laser-heated diamond anvil cell (LHDAC) in combination with numerical simulations of heat transfer in DAC are shown to yield information on thermal conductivity of a pressurized sample. READ MORE

  6. 9. Thermal Conductivity of Hygroscopic Foams Based on Cellulose Nanomaterials

    Author : Varvara Apostolopoulou-Kalkavoura; Lennart Bergström; Tatiana Budtova; Stockholms universitet; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; thermal conductivity; cellulose nanomaterials; foams; hygroscopic; super-insulating; phonon scattering; moisture uptake; heat transport; Materials Chemistry; materialkemi;

    Abstract : Biobased super-insulating materials could mitigate climate change by minimizing the use of petroleum-based materials, creating artificial carbon sinks and minimizing the energy needed to maintain pleasant interior conditions. Cellulose nanomaterials (CNM) produced from abundantly available cellulose sources constitute versatile, highly anisotropic raw materials with tunable surface chemistry and high strength. READ MORE

  7. 10. Proton conductivity in acceptor-doped lanthanide based pyrochlore oxides

    Author : Karinh Eurenius; Göteborgs universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Pyrochlore; Rietveld refinement; Proton conductivity; Electrical impedance spectroscopy; Concentration Cell Electromotive Force Method.;

    Abstract : A high interest in developing new materials for SOFC applications in the temperature range of approximately 200–500 C has been growing lately. The lower activation energies for proton (H+) mobility can give higher conductivity in this temperature range. READ MORE