Tidligere arrangementer - Side 133
Friday seminar by Anders M?ller
Fredagskollokvium
Recent efforts to investigate a possible increased lifetime of old platforms have brought attention to some challenging hydrodynamic problems. Due to higher extreme waves and subsidence of seabed some of these platforms have become vulnerable to wave crests hitting the deck of the platform. Higher estimates of extreme wave crests may be due to better understanding of non-linear wave effects as well as including the uncertainty related to possible climate change effects. Due to complexity of deck geometry, CFD has been found necessary to predict wave impact loads. Numerical procedures to estimate extreme wave crests, obtain corresponding fluid particle kinematics and calculate impact loads will be presented.
J?rn Birknes is scientist at Det Norske Veritas
Friday seminar by Piotr Tryjanowski.
Fredagskollokvium
Friday seminar by Wendy C. Turner
The word seismology is often associated with earthquakes. However, the tightly related term ``seismic'' comprises a valuable technology used extensively by the oil and gas industry in its exploration, development, and reservoir management operations. This talk will explain how marine seismic operations are carried out, and highlight some technological challenges that are faced. Special attention will be given to a factors like wave motion and turbulence, that add complexities to the operational environment. Such factors are challenging to handle from both a fluid dynamical and a signal-processing perspective.
Thomas Elboth is geophysicist at Fugro-Geoteam AS
Fredagskollokvium
The slow growth of a crack in windshield represents a mechano-chemical process: The stress at the tip of the fracture is not high enough to cause rapid fracture motion. Instead, fracture motion is determined by the diffusion of hydrogen to the crack tip, where it weakens the material, leading to crack tip propagation. The velocity of the fracture depends on the coupling between deformation, transport, and reactions. Similar coupled processes determine the rate of many reaction processes of geological relevance, such as weathering and carbonation during mineralogical CO2 sequestration. We have developed numerical model that allow us to address mechano-chemical processes during fluid infiltration. The model demonstrates that fracturing assisted reaction fronts in shrinking materials propagate with a constant velocity and width, and that the reaction rate in volume increasing reactions may be accelerated by feedback processes between fluid flow, mechanical deformation, and reactions.
Anders Malthe-S?renssen is professor at the Department of Physics, working at the center for Physics of Geological Processes
Den ledende forskeren og anerkjente formidleren professor Richard A. Fortey ved Natural History Museum, London, gjester NHM med forelesningen "The fossil record since Darwin".
Friday seminar by Anna Qvarnstr?m.
Fredagskollokvium
Jan Erik H. Weber, Department of Geosciences, University of Oslo G?ran Brostr?m, Norwegian Meteorological Institute, Oslo Nonlinear density-driven convection in a conditionally unstable fluid is studied theoretically. The novelty here is that the destabilizing basic density gradient is expressed in terms of the vertical perturbation velocity through a unit step function. This is done by introducing a one-way source step function due to phase transitions in the equation for the perturbation density. Then we can model the fact that the density-gradient is unstable when the perturbation vertical velocity is upward (positive), and stable when the vertical perturbation velocity is downward (negative), characterizing conditional stability. Linear analytical solutions as well as numerical results for nonlinear two-dimensional steady convection are presented.
Jan Erik Weber is professor at Department of Geosciences
Fredagskollokvium
Det tredje m?te i HR-nettverket tok for seg HR-m?linger. Trenger vi slike m?linger? Hvordan f?lger vi opp resultatene, og er vi profesjonelle nok til ? kunne behandle alle ansatte med integritet og verdighet?
Friday seminar by Stephen H. Schneider and Terry L. Root
Museum collections of fungi - social aspects and value for research, public outreach and nature resource assessment.
Professor Avraham Levy vil forelese over følgende emne: Genetic and epigenetic mechanisms of gene expression rewiring in hybrids and polyploids
Museum collections of fungi - social aspects and value for research, public outreach and nature resource assessment.
Friday seminar by Jon Fjelds?.
Friday seminar by Bernard Cazelles.
Fredagskollokvium
Extra CEES/MERG seminar by Hanna Johannesson.
Friday seminar by Homayoun C. Bagheri