Tech Briefs

A comprehensive library of technical briefs from engineering experts at NASA and major government, university, and commercial laboratories covering all aspects of innovations in electronics, software, photonics, imaging, motion control, automation, sensors, test, materials, manufacturing, mechanical, and mechatronics.

Briefs : Physical Sciences
High-Sensitivity GaN Microchemical Sensors

Systematic studies have been performed on the sensitivity of GaN HEMT (high electron mobility transistor) sensors using various gate electrode designs and operational parameters. The results here show that a higher sensitivity can be achieved with a larger W/L ratio (W = gate width, L = gate length) at...

Briefs : Physical Sciences
On the Divergence of the Velocity Vector in Real-Gas Flow

A theoretical study was performed addressing the degree of applicability or inapplicability, to a real gas, of the occasionally stated belief that for an ideal gas, incompressibility is synonymous with a zero or very low Mach number. The measure of compressibility used in this study is...

Briefs : Information Technology
Integrated Risk and Knowledge Management Program — IRKM-P

The NASA Exploration Systems Mission Directorate (ESMD) IRKM-P tightly couples risk management and knowledge management processes and tools to produce an effective “modern” work environment. IRKM-P objectives include: (1) to learn lessons from past and current programs (Apollo,...

Briefs : Information Technology
Constructing LDPC Codes From Loop-Free Encoding Modules

A method of constructing certain low-density parity-check (LDPC) codes by use of relatively simple loop-free coding modules has been developed. The subclasses of LDPC codes to which the method applies includes accumulate-repeat-accumulate (ARA) codes, accumulate-repeat-check-accumulate...

Briefs : Information Technology
LDPC Codes With Minimum Distance Proportional to Block Size

Low-density parity-check (LDPC) codes characterized by minimum Hamming distances proportional to block sizes have been demonstrated. Like the codes mentioned in the immediately preceding article, the present codes are error-correcting codes suitable for use in a variety of wireless...

Briefs : Electronics & Computers
MMICs With Radial Probe Transitions to Waveguides

A document presents an update on the innovation reported in “Integrated Radial Probe Transition From MMIC to Waveguide” (NPO-43957), NASA Tech Briefs Vol. 31, No. 5 (May 2007), page 38. To recapitulate: To enable operation or testing of a monolithic microwave integrated circuit (MMIC), it is...

Briefs : Electronics & Computers
Tests of Low-Noise MMIC Amplifier Module at 290 to 340 GHz

A document presents data from tests of a low-noise amplifier module operating in the frequency range from 290 to 340 GHz — said to be the highest-frequency low-noise, solid-state amplifier ever developed. The module comprised a three-stage monolithic microwave integrated circuit (MMIC)...

Briefs : Information Technology
Extending Newtonian Dynamics to Include Stochastic Processes

A paper presents further results of continuing research reported in several previous NASA Tech Briefs articles, the two most recent being “Stochastic Representations of Chaos Using Terminal Attractors” (NPO-41519), [Vol. 30, No. 5 (May 2006), page 57] and “Physical Principle for...

Briefs : Physical Sciences
Instruments for Imaging From Far to Near

The acronym “CHAMP” (signifying “camera, hand lens, and microscope”) denotes any of several proposed optoelectronic instruments that would be capable of color imaging at working distances that could be varied continuously through a range from infinity down to several millimeters. As in any optical...

Briefs : Physical Sciences
Reflectors Made From Membranes Stretched Between Beams

Lightweight cylindrical reflectors of a proposed type would be made from reflective membranes stretched between pairs of identically curved and identically oriented end rails. In each such reflector, the curvature of the two beams would define the reflector shape required for the intended...

Briefs : Photonics/Optics
Instruments for Imaging From Far to Near

The acronym “CHAMP” (signifying “camera, hand lens, and microscope”) denotes any of several proposed optoelectronic instruments that would be capable of color imaging at working distances that could be varied continuously through a range from infinity down to several millimeters. As in any optical...

Briefs : Photonics/Optics
Reflectors Made From Membranes Stretched Between Beams

Lightweight cylindrical reflectors of a proposed type would be made from reflective membranes stretched between pairs of identically curved and identically oriented end rails. In each such reflector, the curvature of the two beams would define the reflector shape required for the intended...

Briefs : Physical Sciences
Mid-Infrared Reflectance Imaging of Thermal-Barrier Coatings

An apparatus for mid-infrared reflectance imaging has been developed as means of inspecting for subsurface damage in thermal-barrier coatings (TBCs). The apparatus is designed, more specifically, for imaging the progression of buried delamination cracks in plasma-sprayed...

Briefs : Physical Sciences
Improving the Visible and Infrared Contrast Ratio of Microshutter Arrays

Three device improvements have been developed that dramatically enhance the contrast ratio of microshutters. The goal of a microshutter is to allow as much light through as possible when the shutters are in the open configuration, and preventing any light from passing...

Briefs : Physical Sciences
Improved Scanners for Microscopic Hyperspectral Imaging

Improved scanners to be incorporated into hyperspectral microscope-based imaging systems have been invented. Heretofore, in microscopic imaging, including spectral imaging, it has been customary to either move the specimen relative to the optical assembly that includes the microscope or...

Briefs : Materials
Large-Format Carbon Nanotube Sheets Fabricated With Chemical Vapor Deposition

Carbon nanotube (CNT) sheets, yarns, and their derivative products are beginning to emerge in the marketplace. A productive and scalable manufacturing method utilizes a chemical vapor deposition process for making very-large-format CNT non-woven, textile-like sheets...

Briefs : Materials
Filtering Water by Use of Ultrasonically Vibrated Nanotubes

Devices that could be characterized as acoustically driven molecular sieves have been proposed for filtering water to remove all biological contaminants and all molecules larger than water molecules. Originally intended for purifying wastewater for reuse aboard spacecraft, these devices...

Briefs : Software
Computer Code for Nanostructure Simulation

Due to their small size, nanostructures can have stress and thermal gradients that are larger than any macroscopic analogue. These gradients can lead to specific regions that are susceptible to failure via processes such as plastic deformation by dislocation emission, chemical debonding, and interfacial...

Briefs : Materials
Improvements in Production of Single-Walled Carbon Nanotubes

A continuing program of research and development has been directed toward improvement of a prior batch process in which single-walled carbon nanotubes are formed by catalytic disproportionation of carbon monoxide in a fluidized-bed reactor. The overall effect of the improvements has...

Briefs : Materials
Progress Toward Sequestering Carbon Nanotubes in PmPV

A report reopens the discussion of “Sequestration of Single-Walled Carbon Nanotubes in a Polymer” (MSC-23257), NASA Tech Briefs, Vol. 31, No. 12 (December 2007), page 38. To recapitulate: Sequestration of single-walled carbon nanotubes (SWNTs) in molecules of...

Briefs : Materials
Functionalizing CNTs for Making Epoxy/CNT Composites

Functionalization of carbon nanotubes (CNTs) with linear molecular side chains of polyphenylene ether (PPE) has been shown to be effective in solubilizing the CNTs in the solvent components of solutions that are cast to make epoxy/CNT composite films. (In the absence of solubilization, the...

Briefs : Semiconductors & ICs
Parallel-Processing CMOS Circuitry for M-QAM and 8PSK TCM

There has been some additional development of parts reported in “Multi-Modulator for Bandwidth-Efficient Communication” (NPO-40807), NASA Tech Briefs, Vol. 32, No. 6 (June 2009), page 34. The focus was on

Briefs : Semiconductors & ICs
Circuit for Driving Piezoelectric Transducers

The figure schematically depicts an oscillator circuit for driving a piezoelectric transducer to excite vibrations in a mechanical structure. The circuit was designed and built to satisfy application-specific requirements to drive a selected one of 16 such transducers at a regulated amplitude and...

Briefs : Semiconductors & ICs
Board Saver for Use With Developmental FPGAs

A device denoted a board saver has been developed as a means of reducing wear and tear of a printed-circuit board onto which an antifuse field-programmable gate array (FPGA) is to be eventually soldered permanently after a number of design iterations. The need for the board saver or a similar device...

Briefs : Semiconductors & ICs
Digital Synchronizer Without Metastability

A proposed design for a digital synchronizing circuit would eliminate metastability that plagues flip-flop circuits in digital input/output interfaces. This metastability is associated with sampling, by use of flip-flops, of an external signal that is asynchronous with a clock signal that drives the...

Briefs : Electronics & Computers
Two-Stage Variable Sample-Rate Conversion System

A two-stage variable sample-rate conversion (SRC) system has been proposed as part of a digital signal-processing system in a digital communication radio receiver that utilizes a variety of data rates. The proposed system would be used as an interface between (1) an analog-to-digital converter...

Briefs : Electronics & Computers
Estimating Transmitted-Signal Phase Variations for Uplink Array Antennas

A method of estimating phase drifts of microwave signals distributed to, and transmitted by, antennas in an array involves the use of the signals themselves as phase references. The method was conceived as part of the solution of the problem of maintaining precise phase...

Briefs : Electronics & Computers
Differential InP HEMT MMIC Amplifiers Embedded in Waveguides

Monolithic microwave integrated-circuit (MMIC) amplifiers of a type now being developed for operation at frequencies of hundreds of gigahertz contain InP high- electron-mobility transistors (HEMTs) in a differential configuration. The differential configuration makes it possible to...

Briefs : Electronics & Computers
Compact, Low-Overhead, MIL-STD-1553B Controller

A compact and flexible controller has been developed to provide MIL-STD-1553B Remote Terminal (RT) communications and supporting and related functions with minimal demand on the resources of the system in which the controller is to be installed. (MIL-STD-1553B is a military standard that...

Briefs : Materials
Fluoroester Co-Solvents for Low-Temperature Li⁺ Cells

Electrolytes comprising LiPF6 dissolved in alkyl carbonate/fluoroester mixtures have been found to afford improved low-temperature performance and greater high-temperature resilience in rechargeable lithium-ion electrochemical cells. These and other electrolytes comprising...

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