We present the design and implementation of a very compact adaptive optic system that senses the return light from a sodium guide-star and controls a deformable mirror and a pointing mirror to compensate atmospheric perturbations in the wavefront. The deformable mirror has 19 electrostrictive actuators and triangular subapertures. The wavefront sensor is a Hartmann sensor with lenslets on triangular centers. The high-bandwidth steering mirror assembly incorporates an analog controller that samples the tilt with an avalanche photodiode quad cell. An {line_integral}/25 imaging leg focuses the light into a science camera that can either obtain long-exposure images or speckle data. In laboratory tests overall Strehl ratios were improved by a factor of 3 when a mylar sheet was used as an aberrator. The crossover frequency at unity gain is 30 Hz.

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This paper discusses scientific visualization of scalar and vector fields, particularly relating to clouds and climate modeling. One cloud rendering method applies a 3-D texture to cloudiness contour surfaces, to simulate a view from outer space. The texture is advected by the wind flow, so that it follows the cloud motion. Another technique simulates multiple scattering of incident light from the sun and sky. This paper also presents a simulation of the microscopic cross-bridge motion which powers muscle contraction. It was rendered by ray-tracing contour surfaces of summed Gaussian ellipsoids approximating the actin and myosin protein shapes.

Current designs of fusion-reactor systems seek to use radiation-resistant, low-activation materials that support long service lifetimes and minimize radioactive-waste problems after decommissioning. Reliable assessment of fusion materials performance requires accurate neutron-reaction cross sections and radioactive-decay constants. The problem areas usually involve cross sections since decay parameters tend to be better known. The present study was motivated by two specific questions: (i) Why are the {sup 51}V(n,np){sup 50}Ti cross section values in the ENDF/B-VI library so large (a gas production issue)? (ii) How well known are the cross sections associated with producing 7.4 x 10{sup 5} y {sup 26}Al in silicon carbide by the process {sup 28}Si(n,np+d){sup 27} Al(n,2n){sup 26}Al (a long-lived radioactivity issue)? The energy range 14-15 MeV of the D-T fusion neutrons is emphasized. Cross-section error bars are needed so that uncertainties in the gas and radioactivity generated over the lifetime of a reactor can be estimated. We address this issue by comparing values obtained from prominent evaluated cross-section libraries. Small differences between independent evaluations indicate that a physical quantity is well known while the opposite signals a problem. Hydrogen from {sup 51}V(n,p){sup 51}Ti and helium from {sup 51}V(n,{alpha}){sup 48}Sc are also important sources of gas in vanadium, so …