Briefs : Physical Sciences
Miniature NMR Spectrometers Without Magnets

Miniature, lightweight nuclear-magnetic-resonance (NMR) spectrometers suitable for characterizing ferromagnetic minerals in the field are undergoing development. In previously developed miniature NMR spectrometers, more than half the weight is contributed by permanent magnets. The present developmental...

Briefs : Electronics & Computers
MEMS Design Optimization With FEA

This report examines design considerations in one of the most promising new areas of engineering – Micro Electro Mechanical Systems (MEMS). Designing and optimizing MEMS devices involves unique challenges, including analyzing the inter- dependent physical phenomena to which MEMS devices are sensitive and...

Briefs : Electronics & Computers
Further Developments Regarding Noise-Reducing Slots in QWIPs

A report presents additional information on the devices described in “Noise-Reducing Slots in Quantum-Well Infrared Photodetectors” (NPO-20518), NASA Tech Briefs, Vol. 25, No. 6 (June 2001), page 6a. To recapitulate: it was proposed that incorporation of suitably dimensioned...

Briefs : Information Technology
Time-Parallel Algorithms for Solving PDEs

A report presents additional details about a class of massively parallel algorithms for finite-difference numerical solution of time-dependent partial differential equations (PDEs). Some aspects of these algorithms were described in two previous articles in NASA Tech Briefs; namely, “Massively Parallel...

Briefs : Mechanical & Fluid Systems
Algorithm Computes Kinematics of a Rover on Rocky Terrain

The Rover Analysis Modeling and Simulation (ROAMS) algorithm is to solve the kinematics of a wheeled mo- bile robot (rover) traversing on a rocky terrain. The rover is constructed using a “rocker-bogey-differential” type suspension and steering system as shown in the figure. By...

Briefs : Software
Software for Simultaneous Control of Three Magnetic Bearings

Five-Axis, Three-Magnetic-Bearing Control Code (FATMaCC) is a C++-language computer program for controlling a magnetic thrust bearing in one degree of freedom and two magnetic radial bearings, each in two degrees of freedom. These bearings levitate a vertical-axis rotor for experiments...

Briefs : Mechanical & Fluid Systems
Crowned Races for Crossed Roller Bearings

Crowned races have been proposed for crossed roller bearings. Crowning of the races is expected to reduce scuffing of the cylindrical rollers. Crowning of the races is expected to be especially beneficial in bearings made of polymers (instead of metals) to reduce weight.

Briefs : Photonics/Optics
Fabricating Sapphire Optical Fibers for High-Temperature Use

A process for the fabrication of coated sapphire multimode optical fibers has been developed. Sapphire multimode optical fibers are suitable for use as embedded sensors for measuring mechanical and thermal stresses and strains in material specimens at temperatures up to about 1,500...

Briefs : Electronics & Computers
Improved Array of Switches for Fiber-Optic Communications

A rectangular array of Y-junction electro-optical switches has been proposed as a prototype of reliable, high-speed cross-point switches for fiber-optic-based photonic communication systems. The proposed array would feature a hybrid digital/interference design. The proposed array would...

Briefs : Photonics/Optics
Microcavity Device for Measuring Direction of a Laser Beacon

An optoelectronic device based on interferometry in a resonant microcavity has been proposed for use in measuring the direction of arrival of a circularly polarized beam of light from a beacon laser. In comparison with prior optoelectronic direction sensors, the proposed device would...

Briefs : Photonics/Optics
Etching Mirror Facets on SOI Optical Waveguides

A process that would include a combination of dry and wet chemical etching has been proposed for making facets for low-loss mirrors on silicon-on-insulator (SOI) optical waveguides. Heretofore, such facets have been made by a process that includes dicing and polishing. This process is...

Briefs : Materials
Improved Conversion Coating for Protection of Metals

A simple, cost effective, environmentally friendly conversion-coating process has been developed for protecting a variety of metals against wear and corrosion and to increase adhesion of paints. This process results in the deposition of a thin, adherent coats of iron phosphate on treated metal...

Briefs : Materials
Composite-Material Structures for Absorbing Crash Energy

Improved lightweight composite-material structures have been invented to protect persons and equipment during aircraft and ground-vehicle crashes. These structures are designed to hold their initial shapes and sustain rated loads under normal operating conditions and, during crashes, to...

Briefs : Materials
Chevrel Phases as Potential Thermoelectric Materials

Crystalline phases of compounds of general composition (Cuw, CuxFey, or Tiz)Mo6Se8 [where w<4, x<2, y<1, and z<1] have been investigated for potential utility as thermoelectric materials for generation of electric...

Briefs : Materials
Alkyl Pyrocarbonate Electrolyte Additives for Li-Ion Cells

Alkyl pyrocarbonates have been found to be useful as electrolyte additives for improving the low-temperature performances of rechargeable lithium-ion electrochemical cells. The beneficial effects of these and other additives have been investigated, along with various electrolyte...

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