The thermal diffusivity of a series of solid solutions of alumina and chromia transformation toughened with a dispersed phase of unstabilized zirconia was measured by means of the laser-flash method from room temperature to 1400 ~ C. It was found, in general, that the thermal diffusivity could be decreased significantly by the combined effects of solid solution alloying, microcracking and by th...

A data reduction method based on numerical solutions of the heat conduction equation has been developed for obtaining thermal diffusivity values from thermal flash measurements. Using the new method, the computed evolution in temperature is fitted to the measured temperature evolution instead of using the t1/2 point alone, as is done in many other analyzes. The numerical solutions used are base...

Induction heating is a process whereby heat is generated in electrically conducting materials through ohmic losses from eddy currents induced by varying electromagnetic fields. This phenomenon can be described by a heat transfer equation and an eddy current equation. These two equations are coupled because most of the material properties are temperature-dependent. In this report a description i...

This work is devoted to exploring a new procedure to develop subgrid-scale (SGS) models in the context of large-eddy simulation (LES) of a passive scalar. Starting from the Noll’s formula (Noll 1967), the concept of an optimal estimator is first used to determine an accurate set of parameters to derive a SGS model. The SGS model is then defined as a surrogate model built from this set of parame...

In order to compute the turbulent electromotive force, the vertical momentum equation for the galactic gas is solved. The only input is the density profile of the gaseous disk. The resulting-effect, the advection terms as well as the eddy diffusivity tensor are quenched by the feedback of the magnetic field. The only free parameters are the factor in the vertical structure equation and a " mixi...

Temperature and salinity profiles obtained with expendable CTD probes throughout Drake Passage between February 2002 and July 2005 are analyzed to estimate turbulent diapycnal eddy diffusivities to a depth of 1000 m. Diffusivity values are inferred from density/temperature inversions and internal wave vertical strain. Both methods reveal the same pattern of spatial variability across Drake Pass...