We show quantitatively how the collision rate of droplets of visible moisture in turbulent air increases very abruptly as the intensity of the turbulence passes a threshold, due to the formation of fold caustics in their velocity field. The formation of caustics is an activated process, in which a measure of the intensity of the turbulence, termed the Stokes number St, is analogous to temperatu...

Hydrofluoric acid is a strong inorganic acid. It differs from other acids in that the fluoride ion readily penetrates the skin, causing destruction of deep tissue layers and even bone. Burns caused by hydrofluoric acid can be life-threatening. The specific antidote, calcium gluconate, can be applied topically, injected into tissue or infused intra-arterially. Emergency medical teams should be f...

Severe gastrointestinal-tract injury due to ingestion of caustic substances is not an infrequent problem in the emergency department. We report the case of a 57-year-old male who developed massive hemorrhagic, caustic gastric necrosis due to the ingestion of a non-diluted solution containing hydrochloric acid, which propitiated an urgent surgical procedure. The esophago-gastrectomy specimen sho...

This dissertation discusses work that enables the realistic image synthesis of very complex scenes. Some of the work herein describes approaches for modeling more complicated scenes, while other portions describe algorithms for accelerating the rendering of complex scenes. First we propose a simple method for modeling and rendering refractive objects that are nested within each other. The techn...

The Hodge equations for 1-forms are studied on Beltrami’s projective disc model for hyperbolic space. Ideal points lying beyond projective infinity arise naturally in both the geometric and analytic arguments. An existence theorem for weakly harmonic 1-fields, changing type on the unit circle, is derived under Dirichlet conditions imposed on the non-characteristic portion of the boundary. A sim...

Underwater, natural illumination typically varies strongly temporally and spatially. The reason is that waves on the water surface refract light into the water in a spatiotemporally varying manner. The resulting underwater illumination field forms a caustic network and is known as flicker. This work shows that caustics can be useful for stereoscopic vision, naturally leading to range mapping of...