October 1998

Briefs : Software
Program Computes Equilibrium Compositions of Mixtures

The Chemical Equilibrium with Applications (CEA) computer program is used to obtain chemical-equilibrium compositions of complex mixtures. This program can be applied to a wide variety of problems in chemistry and chemical engineering. Specifically, CEA is applicable to the following kinds of...

Briefs : Photonics/Optics
Noncontacting Resonant Ultrasound Spectroscopy for Nondestructive Evaluation

An important nondestructive evaluation (NDE) measurement technique is to record the vibration-mode spectrum of a material part or structure, excited by a random or a driven source (i.e., acoustic coupling or shaker table). The vibration-mode spectrum fully describes the...

Briefs : Mechanical & Fluid Systems
Latching Devices for Electrical and Mechanical Connections

Latching devices have been developed to provide electrical connections, secure mechanical and thermal connections, and optical alignment for mounting electronically controlled cameras on the spaceborne laboratory apparatus described in the preceding article. Traditionally, the...

Briefs : Mechanical & Fluid Systems
Replaceable Windows With Alignment and Sealing Features

Window assemblies (see figure) have been developed to satisfy special requirements pertaining to ease of replacement, alignment, sealing, and resistance to vibration in a spaceborne laboratory apparatus for experiments on combustion in microgravity. These window assemblies are also well...

Briefs : Information Technology
Localization by Maximum-Likelihood Matching of Range Maps

A procedure for determining the location of an instrumentation platform on natural terrain is based on a concept of maximum-likelihood matching of two range maps: (1) a local range map generated by processing of images of the terrain in the immediate vicinity acquired by stereoscopic...

Briefs : Electronics & Computers
Development of Circuitry for Wristband Radio Transponders

A document proposes the development of several alternative types of electronic circuits for wristband transponders for the system described in "Person-Locator System Based on Wristband Radio Transponders" (NPO-19280) NASA Tech Briefs, Vol. 19, No. 12 (December 1995), page 40. To...

Briefs : Photonics/Optics
Versatile Transparent-Melt Crystal-Growth Systems for Organic Nonlinear Optical Materials Using Bridgman-Stockbarger Technique

Single crystals of benzil, benzil aniline, and salicylidene-aniline have been successfully grown using a modified Bridgman-Stockbarger technique for three different crystal-growth systems. The unique feature of the...

Briefs : Electronics & Computers
Active-Pixel Sensors With "Winner-Take-All" Mode

Circuits to generate the intensity reading and the coordinates of the brightest pixel in each image would be added to imaging photodetector arrays of the active-pixel-sensor (APS) type, according to a proposal. For a given APS, the additional circuitry for locating the brightest pixel would be...

Briefs : Electronics & Computers
Monolithic GaAs FET Power Amplifiers for Kₐ Band

A program to demonstrate the feasibility of GaAs-based Kₐ-band power amplifiers has generated a number of technological advances. The goals of the program included (1) capability of amplifier operation at center frequencies of 23, 29, and 32.5 GHz; (2) bandwidth of 5 percent at each center...

Briefs : Electronics & Computers
Active-Pixel-Sensor Digital Camera on a Single Chip

The figure shows a complementary metal oxide/semiconductor (CMOS) integrated circuit that contains all of the electronic circuitry of a programmable active-pixel-sensor digital camera. Heretofore, digital cameras have been assembled from charge-coupled-device (CCD) chips, separate...

Briefs : Robotics, Automation & Control
Sorption Compressor for Collecting Atmospheric CO₂ on Mars

A report describes a small, lightweight sorption compressor that is now undergoing development for use in collecting CO2 from the atmosphere on Mars. This compressor would be part of a system that would use the CO2 to generate oxygen and a carbon-based fuel for a...

Briefs : Electronics & Computers
Augmented Active-Pixel Sensors Would Compute Centers of Mass

Circuits to generate analog or digital representations of the coordinates of the centers of mass of images would be added to imaging photodetector arrays of the active-pixel-sensor (APS) type, according to a proposal. "Centers of mass" as used here is something of a misnomer of...

Briefs : Electronics & Computers
Computers for Research on Flight Control in F/A-18 Airplanes

The Production Support Flight Control Computers (PSFCCs) are flight-control computers that are being developed by NASA in conjunction with the United States Navy. These computers are designed to provide any of the F/A-18 airplanes at NASA Dryden Flight Research Center with capabilities...

Briefs : Physical Sciences
Microfabricated Ice Sensors

Microfabricated, silicon-based capacitive actuator/sensor devices have been developed as prototypes of compact, low-power transducers that would be used to detect the presence (and perhaps eventually measure the thickness) of ice on aircraft lift and control surfaces. These transducers would be mounted flush with...

Briefs : Materials
Improved Process for Scrubbing and Treating NOₓ Liquor

A new process and equipment have been developed for reducing the emissions of hazardous nitrogen oxides (NOx), and eliminating a hazardous waste stream. In this process, a waste gas stream of nitrogen and NOx, arising from spacecraft-propellant operations, is reacted...

Briefs : Manufacturing & Prototyping
Fabricating Refractory-Metal Solar-Engine Components by VPS

Vacuum plasma spraying (VPS) has been demonstrated to be an effective technique for the fabrication of refractory-metal components of solar-thermal engines. Heretofore, such components have been fabricated by specialized techniques that include electrical-discharge machining, shear...

Briefs : Electronics & Computers
GPS-Based System Tracks Relative Position of Two Airplanes

A developmental electronic system that includes Global Positioning System (GPS) receivers is designed to track the relative position and velocity to two airplanes in real time. In the original application for which the system is being developed, one F-18 airplane (denoted the "chase...

Briefs : Electronics & Computers
Optimized Two-Wavelength Focal-Plane Arrays of QWIPs

A concept for optimizing the designs of two-wavelength GaAs-based quantum-well infrared photodetectors (QWIPs) could make it practical to use focal-plane arrays of QWIPs as image sensors in two-wavelength infrared cameras. Potential applications for such cameras include surveillance, tracking...

Briefs : Robotics, Automation & Control
Vacuum Three-Ball Tribometer for Testing Liquid Lubricants

A three-ball tribometer has been developed for use in evaluating the performances of oils and greases as lubricants in a vacuum at room temperature. This apparatus differs from the one described in "Vacuum Four-Ball Tribometer for Testing Liquid Lubricants" (LEW-16194), NASA Tech Briefs,...

Briefs : Physical Sciences
Methanol-Fuel-Cell Biplate Improved for Removal of Water

An improved design for a biplate in a methanol fuel cell provides increased efficiency in the removal of water, relative to older designs. For reasons explained below, this design both improves the performance of the fuel cell and increases the overall energy efficiency of the...

Briefs : Physical Sciences
Study of DLS Monitoring of the Growth of Protein Crystals

A report describes an experimental study of whether an advanced fiber-optic dynamic-light-scattering (DLS) probe affords a capability for noncontact detection of particles of various sizes associated with the stages of growth of protein crystals in automated hanging-drop protein-growth...

Briefs : Electronics & Computers
System-Level Integrated Circuits for Phased-Array Antennas

Modules of electronic circuitry that perform the amplitude- and phase-control and the status-monitoring functions for eight-element (2 ×4) subarrays of K-band phased-array antennas have been developed as prototype building blocks for future phased-array antennas. These modules are...

Briefs : Mechanical & Fluid Systems
Penetrator Projectile Tolerates Some Misalignment

A two-body design has enabled an instrumented penetrator projectile to function with increased tolerance to initial misalignment among (a) the longitudinal axis of the penetrator, (b) the velocity of impact on the ground, and (c) the local perpendicular to the surface at the point of impact. In...

Briefs : Robotics, Automation & Control
Mars Lander

A brief report presents drawings for the conceptual design of a spacecraft that would land on Mars or another remote planet. The spacecraft would have a tetrahedral shape, would include airbags to cushion impact, and would have a self-righting capability. The drawings show the general appearance of the spacecraft and show the...

Briefs : Materials
Rapid Densification of Ceramic Monoliths and Composites

A rapid densification technology uses nanostructured powders to produce ceramic devices and components. This technology provides ceramic monoliths and composites that can be used in the automobile, energy, electrochemical, magnetic, structural, biomedical, computing, information-transfer,...

Briefs : Photonics/Optics
Delta-Doped Hybrid Advanced Detector

The delta-doped hybrid advanced detector is a developmental integrated electronic imaging and detecting circuit designed to be sensitive to (1) charged particles with kinetic energies ranging from hundreds through millions of electron volts and (2) photons ranging from visible light to x rays. Heretofore, the...

Briefs : Manufacturing & Prototyping
Improved Packaging of Silica Optical Fibers in Sensor Heads

A process for the fabrication of improved high-temperature fiber-optic sensor heads has been proposed. Fiber-optic sensor heads that can withstand hot, dirty, noisy environments are needed for advanced jet engines and stationary power-generating turbine engines.

Briefs : Photonics/Optics
Vapor Drying for Preparing InGaAsP for Epitaxial Regrowth

A vapor drying treatment removes traces of water and other contaminant residues that remain on the surface of a patterned semiconductor substrate after chemical cleaning in preparation for subsequent epitaxial growth on the substrate. The treatment was developed in conjunction with...

Briefs : Electronics & Computers
Information-Reduced Carrier Synchronization for Coded PSK Operation at Low-SNR

An information-reduced carrier-synchronization (IRCS) system has been proposed for use in a coded binary-phase-shift-keying (BPSK) radio-communication receiver subject to a low signal-to-noise ratio (SNR). The term "information-reduced" alludes to the use of an...

Briefs : Photonics/Optics
Fabrication of Diffractive GaAs Microlenses

A planar array of microscopic diffractive optical elements that resemble macroscopic Fresnel lenses can be fabricated as an array of continuous relief patterns on a GaAs substrate by a procedure that includes the transfer of a corresponding array of patterns formed on a surface layer of poly(methyl...

Briefs : Electronics & Computers
Micromachined Magnetostatic Switches

Magnetostatic switches — switches that open or close in response to magnetic fields — are being developed and fabricated using micromachining (MEMS) technology. These switches operate similarly to traditional magnetic reed switches, but can be made much smaller. While capable of serving as direct...

Briefs : Mechanical & Fluid Systems
Robot Hands With Electroactive-Polymer Fingers

Multifinger electroactive-polymer grippers (MEPGs) are simple, compact, lightweight robotic end effectors with fingers that bend and function similarly to human fingers. The fingers are made from electroactive polymers, which are well suited to use in bending-type actuators because they can be...


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