Physically principled reflection models applied to filtered camera imaging inversions in metal walled fusion machines

Ray-tracing techniques are applied to filtered divertor imaging, a diagnostic that has long suffered from artifacts due to the polluting effect of reflected light in metal walled fusion machines. Physically realistic surface reflections were modeled using a Cook-Torrance micro-facet bi-directional reflection distribution function applied to a high resolution mesh of the vessel geometry. In the absence of gonioreflectometer measurements, a technique was developed to fit the free parameters of the Cook-Torrance model against images of the JET in-vessel light sources. By coupling this model with high fidelity plasma fluid simulations, photo-realistic renderings of a number of tokamak plasma emission scenarios were generated. Finally, a sensitivity matrix describing the optical coupling of a JET divertor camera and the emission profile of the plasma was obtained, including full reflection effects. These matrices are used to perform inversions on measured data and shown to reduce the level of artifacts in inverted emission profiles.

Spatial pattern of sensory cell terminals in the olfactory sac of the tiger salamander. I. A scanning electron microscope study

The olfactory sac of adult tiger salamanders (Ambystoma tigrinum) was assessed by scanning electron microscopy and the hitherto unknown variety of the olfactory sac cells has been documented. Regional differences in respect to the composition of the apical epithelial surface border in the olfactory sac have been recorded. Transitions between the olfactory epithelium proper and epithelia with different surface structures have been described. It has been shown that both the roof and the floor of the olfactory sac are mainly covered by sensory epithelium with a surface of uniform appearance. However, the sensory area of the floor is interspaced with non-olfactory epithelial bands. Variations were also noted in regard to secretory cells, cells with conical profiles, microplicae arrangements and populations of microvilli and kinocilia. These differences have been discussed in relation to electrophysiological data which suggest a regional patterning in the response to odours.