Manufactured single crystal components using Ni-base super alloys are routinely used in the hot sections of aero engines and industrial gas turbines due to their outstanding high temperature strength, toughness and resistance to degradation in corrosive and oxidative environments. To control the quality of the single crystal turbine blades, particular attention has been paid to grain selection,...

Manufactured single crystal components using Ni-base super alloys are routinely used in the hot sections of aero engines and industrial gas turbines due to their outstanding high temperature strength, toughness and resistance to degradation in corrosive and oxidative environments. To control the quality of the single crystal turbine blades, particular attention has been paid to grain selection,...

We numerically study the spiral mode of crystal growth using a theory developed by Burton, Cabrera and Frank using a level set method. This method is novel in that it can handle not only closed curves but open curves as well. We use our method to compute interacting spirals and make estimates of growth rates. We also propose a possible coarsening mechanism for a large number of interacting spir...

manufactured single crystal components using ni-base super alloys are routinely used in the hotsections of aero engines and industrial gas turbines due to their outstanding high temperaturestrength, toughness and resistance to degradation in corrosive and oxidative environments. tocontrol the quality of the single crystal turbine blades, particular attention has been paid to grainselection, whi...

Spiral surface growth is well understood in the limit where the step motion is controlled by the local supersaturation of adatoms near the spiral ridge. In epitaxial thin-film growth, however, spirals can form in a step-flow regime where desorption of adatoms is negligible and the ridge dynamics is governed by the non-local diffusion field of adatoms on the whole surface. We investigate this li...

We have obtained deep near-infrared Ks-band William Herschel Telescope observations of a sample of 15 nearby spiral galaxies having a range of Hubble types and apparent bar strengths. The near-infrared light distributions are converted into gravitational potentials, and the maximum relative gravitational torques due to the bars and the spirals are estimated. We find that spiral strength, Qs, an...