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 : 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...

Briefs : Materials
Improved Aerogel Vacuum Thermal Insulation

An improved design concept for aerogel vacuum thermal-insulation panels calls for multiple layers of aerogel sandwiched between layers of aluminized Mylar (or equivalent) poly(ethylene terephthalate), as depicted in the figure. This concept is applicable to both the rigid (brick) form and the flexible...

Briefs : Materials
Using Volcanic Ash To Remove Dissolved Uranium and Lead

Experiments have shown that significant fractions of uranium, lead, and possibly other toxic and/or radioactive substances can be removed from an aqueous solution by simply exposing the solution, at ambient temperature, to a treatment medium that includes weathered volcanic ash from Pu’u...

Briefs : Manufacturing & Prototyping
High-Efficiency Artificial Photosynthesis Using a Novel Alkaline Membrane Cell

A new cell designed to mimic the photosynthetic processes of plants to convert carbon dioxide into carbonaceous products and oxygen at high efficiency, has an improved configuration using a polymer membrane electrolyte and an alkaline medium. This increases efficiency...

Briefs : Manufacturing & Prototyping
Silicon Wafer-Scale Substrate for Microshutters and Detector Arrays

The silicon substrate carrier was created so that a large-area array (in this case 62,000+ elements of a microshutter array) and a variety of discrete passive and active devices could be mounted on a single board, similar to a printed circuit board. However, the density and...

Briefs : Mechanical & Fluid Systems
Micro-Horn Arrays for Ultrasonic Impedance Matching

Thin-layered structures containing arrays of micromachined horns, denoted solid micro-horn arrays (SMIHAs), have been conceived as improved means of matching acoustic impedances between ultrasonic transducers and the media with which the transducers are required to exchange acoustic energy....

Briefs : Mechanical & Fluid Systems
Improved Controller for a Three-Axis Piezoelectric Stage

An improved closed-loop controller has been built for a three-axis piezoelectric positioning stage. The stage can be any of a number of commercially available or custom-made units that are used for precise three-axis positioning of optics in astronomical instruments and could be used for...

Briefs : Physical Sciences
Dynamic Self-Locking of an OEO Containing a VCSEL

A method of dynamic self-locking has been demonstrated to be effective as a means of stabilizing the wavelength of light emitted by a vertical-cavity surface-emitting laser (VCSEL) that is an active element in the frequency-control loop of an optoelectronic oscillator (OEO) designed to implement...

Briefs : Physical Sciences
Nonlinear Thermal Compensators for WGM Resonators

In an alternative version of a proposed bimaterial thermal compensator for a whispering-gallery-mode (WGM) optical resonator, a mechanical element having nonlinear stiffness would be added to enable stabilization of a desired resonance frequency at a suitable fixed working temperature. The...

Briefs : Physical Sciences
Internal Water Vapor Photoacoustic Calibration

Water vapor absorption is ubiquitous in the infrared wavelength range where photoacoustic trace gas detectors operate. This technique allows for discontinuous wavelength tuning by temperature-jumping a laser diode from one range to another within a time span suitable for photoacoustic calibration....

Briefs : Information Technology
Rate-Compatible LDPC Codes With Linear Minimum Distance

A recently developed method of constructing protograph-based low-density parity-check (LDPC) codes provides for low iterative decoding thresholds and minimum distances proportional to block sizes, and can be used for various code rates. A code constructed by this method can have either...

Briefs : Information Technology
Minimizing Input-to-Output Latency in Virtual Environment

A method and apparatus were developed to minimize latency (time delay) in virtual environment (VE) and other discrete-time computer-based systems that require real-time display in response to sensor inputs. Latency in such systems is due to the sum of the finite time required for...

Briefs : Information Technology
PrimeSupplier Cross-Program Impact Analysis and Supplier Stability Indicator Simulation Model

PrimeSupplier, a supplier cross-program and element-impact simulation model, with supplier solvency indicator (SSI), has been developed so that the shuttle program can see early indicators of supplier and product line stability, while identifying the...

Briefs : Information Technology
Integrated Planning for Telepresence With Time Delays

A conceptual “intelligent assistant” and an artificial-intelligence computer program that implements the intelligent assistant have been developed to improve control exerted by a human supervisor over a robot that is so distant that communication between the human and the robot involves...

Briefs : Electronics & Computers
Battery Cell Voltage Sensing and Balancing Using Addressable Transformers

A document discusses the use of saturating transformers in a matrix arrangement to address individual cells in a high-voltage battery. This arrangement is able to monitor and charge individual cells while limiting the complexity of circuitry in the battery. The arrangement...

Briefs : Information Technology
Gaussian and Lognormal Models of Hurricane Gust Factors

A document describes a tool that predicts the likelihood of land-falling tropical storms and hurricanes exceeding specified peak speeds, given the mean wind speed at various heights of up to 500 feet (150 meters) above ground level. Empirical models to calculate mean and standard deviation...

Briefs : Software
Qualifying Software for Nuclear-Safety-Related Calculations

The Department of Energy’s (DOE) Oak Ridge National Laboratory (ORNL) High Flux Isotope Reactor (HFIR) is the highest- flux reactor-based source of neutrons for condensed-matter research in the US. Thermal and cold neutrons produced by HFIR are used to study physics, chemistry,...

Briefs : Software
Acoustic Structure Interactions

For a wide range of engineers and scientists, the sound generated by a vibrating structure represents a critically important phenomenon. These sounds can be of significance for accomplishing rapid, low-cost inspection of critical infrastructure. For example, there are approximately 600,000 highway bridges in the...

Briefs : Software
Analysis of Transient Electric Dipole

Propagation characteristics of electromagnetic waves generated by an electric dipole are used for a variety of applications, including geological mapping of mineral deposits on the ocean floor, cellular or mobile communications, and detection of unexploded ordnance. Mapping of the regional geology in...

Briefs : Software
Spacecraft Station-Keeping Trajectory and Mission Design Tools

Two tools were developed for designing station-keeping trajectories and estimating delta-v requirements for designing missions to a small body such as a comet or asteroid. This innovation uses NPOPT, a non-sparse, general-purpose sequential quadratic programming (SQP) optimizer and...

Briefs : Software
Integrated Modeling of Spacecraft Touch-And-Go SamplingIntegrated Modeling of Spacecraft Touch-And-Go Sampling

An integrated modeling tool has been developed to include multi-body dynamics, orbital dynamics, and touch-and-go dynamics for spacecraft covering three types of end- effectors: a sticky pad, a brush-wheel sampler, and a pellet gun.

Briefs : Software
Simulation of Attitude and Trajectory Dynamics and Control of Multiple Spacecraft

Agora software is a simulation of spacecraft attitude and orbit dynamics. It supports spacecraft models composed of multiple rigid bodies or flexible structural models. Agora simulates multiple spacecraft simultaneously, supporting rendezvous, proximity operations,...

Briefs : Software
Port-O-Sim Object Simulation Application

Port-O-Sim is a software application that supports engineering modeling and simulation of launch-range systems and subsystems, as well as the vehicles that operate on them. It is flexible, distributed, object-oriented, and real-time. A scripting language is used to configure an array of simulation objects...

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