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Visar resultat 1 - 5 av 9 avhandlingar som matchar ovanstående sökkriterier.
1. Subsurface fluxes of mass and energy at the accumulation zone of Lomonosovfonna ice cap, Svalbard
Sammanfattning : Glaciers cover ca 10% of the Earth's land and are found in the high altitudes and latitudes. They are important components of environmental systems due to the multiple feedbacks linking them with the atmosphere, hydrosphere and periglacial landscapes. LÄS MER
2. Thermal Conductivity of Materials under Conditions of Planetary Interiors
Sammanfattning : 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. LÄS MER
3. Functional and structural characterizations of phytoplankton-bacteria interactions in response to environmental challenges
Sammanfattning : Microorganisms, such as phytoplankton and bacteria, make up ≈70% of aquatic biomass and contribute 50-85% of the oxygen in Earth’s atmosphere. The microbial loop concept and the discovery of the large diversity in microbial communities acknowledge that biotic interactions between microorganisms in addition to resource competition enable the recycling of energy and nutrients in aquatic food webs. LÄS MER
4. Atomistic Computer Simulations of the Melting Process and High Pressure Conditions
Sammanfattning : The present work describes the use of atomistic computer simulations in the area of Condensed Matter Physics, and specifically its application to the study of two problems: the dynamics of the melting phase transition and the properties of materials at extreme high pressures and temperatures, problems which defy experimental measurements and purely analytical calculations. Both classical Molecular Dynamics (using semi–empirical interaction potentials) and first–principles (ab initio) Molecular Dynamics techniques has been applied in this study to the calculation of melting curves in a wide range of pressures for elements such as Xe and H2, the study of the elastic constants of Fe at the conditions of the Earth’s inner core, and the characterization of diffusion and defects formation in a generic Lennard–Jones crystal at the limit of superheating, including the role they play in the triggering of the melting process itself. LÄS MER
5. Influence of stresses and impurities on thermodynamic and elastic properties of metals and alloys from ab initio theory
Sammanfattning : Stresses and impurities may influence elastic properties, phase stability and magnetic behavior of metals and their alloys. A physical understanding of this influence is of great importance to both fundamental science and technological applications. LÄS MER
