Physical Sciences

Image-plane multidither sensing has been found to be suitable for adaptive wavefront correction in a large telescope in which the main optic is a precise reflector divided into lightweight, controllably actuated segments. In image-plane multidither sensing, the telescope is aimed at a star...

A two-photon microscope imaging spectrometer has been proposed for use in scanning confocal two-photon microscopy. The proposed instrument would solve a spectrum-overlap that sometimes arises, as explained below.

A report proposes the use of lightweight balloon-borne instrumentation systems for exploration in the vicinity of a lander on the surface of Mars. Each system would comprise instrumentation with a mass of about 0.2 kg and a balloon with a mass of about 0.8 kg and volume of about 50 m3. The...

Experiments have demonstrated the feasibility of detecting multiple species of toxic metal ions and other ions of interest dissolved in water, by means of voltammetry with electrically conductive artificial diamond electrodes. Diamond is attractive as an electrode material because it is...

Electromagnetic particle-in-cell (EMPIC) codes provide a capability for numerically simulating the motions of electrically charged particles in electromagnetic fields, and hence have become standard software tools in plasma physics research. Most existing EMPIC codes are based on the use of...

A report discusses alternative techniques for controlling the buoyancy, and thus the altitude and landings, of a balloon-borne instrumentation system that would be launched to explore the moon Titan of the planet Saturn. Some of the techniques are based on established concepts of heating or...

Pressure sensors that contain thin diaphragms made from the 6H polytype of silicon carbide (6H-SiC) have been developed. These are prototypes of pressure sensors for use at high temperatures in engines, power plants, material-processing systems, and numerous other applications.

The Generalized Fluid System Simulation Program (GFSSP) version 2.01 is a general-purpose computer program for analyzing steady-state and time-dependent flowrates, pressures, temperatures, and concentrations in a complex flow network. The program is capable of modeling phase changes,...

A collection of three reports presents an expanded discussion of the topic of "Optical Diagnostics of High-Pressure Liquid Fuel Sprays" (LEW-16701),NASA Tech Briefs, Vol. 23, No. 3 (March 1999), page 18a. The reports describe experiments in which fuel sprays representative of those in...

A paper describes the mathematical basis and some applications of a class of massively parallel algorithms for finite-difference numerical solution of some time-dependent partial differential equations (PDEs) on massively parallel supercomputers. In a radical departure from the traditional...

Hydrazine, monomethylhydrazine, and unsymmetrical dimethylhydrazine can be detected and measured at concentrations as low as 10 parts per billion in the presence of ammonia at concentrations as high as 10 parts per million (greater than the odor threshold concentration of ammonia,...

Glenn-HT is a computational fluid dynamics (CFD) computer code for the analysis of three-dimensional flow and convective heat transfer in a gas turbine. Glenn-HT has been evolving during the past few years at Glenn Research Center, and at least 35 technical papers relative to this code have...