Special Coverage

Soft Robot “Walks” on Any Terrain
Defense Advanced Research Projects Agency
Using Microwaves to Produce High-Quality Graphene
Transducer-Actuator Systems for On-Machine Measurements and Automatic Part Alignment
Wide-Area Surveillance Using HD LWIR Uncooled Sensors
Heavy Lift Wing in Ground (WIG) Cargo Flying Boat
Technique Provides Security for Multi-Robot Systems
Bringing New Vision to Laser Material Processing Systems
NASA Tests Lasers’ Ability to Transmit Data from Space
Converting from Hydraulic Cylinders to Electric Actuators
Automating Optimization and Design Tasks Across Disciplines

System for Monitoring the Environment of a Spacecraft Launch

A system that includes sensors and computers that communicate via an intranet enables both real-time monitoring and subsequent analysis of acoustic, overpressure, and thermal aspects of a spacecraft-launch environment and the structural response (vibration and strain) to that environment. The sensors include microphones, accelerometers, strain gauges, and a thermocouple attached to a cantilever beam mounted vertically on the roof of a building near a launch pad. The sensors are connected via cables to signal conditioners inside the building. The conditioned sensor outputs are coupled to a digital audio tape (DAT) recorder that is monitored and controlled by a computer denoted the "remote" computer. A host computer in a different building communicates with the remote computer via the intranet, using the Transmission Control Protocol/Internet Protocol. Ambient test conditions can be monitored in real time before a launch. Last-minute adjustments can be accomplished remotely and dynamically. A few minutes before the launch, the DAT recorder is turned on to record launch events. Data can be monitored in real time during the launch. After the launch, data can be copied from the DAT recorder onto the remote computer and then transferred to the host computer for plotting and analysis.

Posted in: Briefs, Electronics & Computers, Analysis methodologies, Sensors and actuators, Sensors and actuators, Launch vehicles, Spacecraft

Measurement of Stresses and Strains in Muscles and Tendons

Small, electrically and chemically neutral sensors would be implanted surgically.

Miniature fiber-optic-coupled sensors based on optically excited, self-resonant microbeams are being developed for measuring stresses and strains within muscle fascicles and tendons. These sensors could be used in medical and biological research on humans and other animals, or to obtain data for the design of lifelike robots.

Posted in: Briefs, TSP, Test & Measurement, Fiber optics, Sensors and actuators, Fiber optics, Sensors and actuators, Medical, health, and wellness

Optical Measurement of Temperatures in Muscles and Tendons

Small, electrically and chemically neutral sensors would be implanted surgically.

Miniature fiber-optic-coupled sensors based on optically excited, self-resonant microbeams have been proposed for measuring temperatures within muscle fascicles and tendons. The proposed sensors could be used in medical and biological research on humans and other animals. The proposed sensors would be variants of those described in several previous articles in NASA Tech Briefs: "Proximity Measurement of Pressure and Temperature" (NPO-20223), Vol. 22, No. 1 (January 1998), page 48; and "Measurement of Stresses and Strains in Muscles and Tendons" elsewhere in this issue.

Posted in: Briefs, TSP, Test & Measurement, Fiber optics, Sensors and actuators, Fiber optics, Sensors and actuators, Medical, health, and wellness

Small Low-Temperature Thermometer With Nanokelvin Resolution

The magnetic field is generated by permanent magnets instead of a solenoid.

An improved high-resolution thermometer (HRT) for use in scientific experiments at temperatures

Posted in: Briefs, TSP, Test & Measurement, Measurements, Test equipment and instrumentation

Heterodyne Interferometer With Phase-Modulated Carrier

Resolution and working distance are increased.

A heterodyne optical interferometer of a type used to measure small displacements can be augmented to suppress a phenomenon, called "self-interference," that tends to limit the achievable resolution and working distance and can even render the interferometer inoperable. The technique for suppressing self-interference can be implemented by use of commercial off-the-shelf optoelectronic and electro-optical components, and does not degrade the fundamental operation of the interferometer.

Posted in: Briefs, TSP, Electronics & Computers, Measurements, Test equipment and instrumentation

Rechargeable Batteries Based on Intercalation in Graphite

Batteries could be recharged thermally or electrically.

Storage batteries based on intercalation of lithium and bromine in graphite have been proposed. Like other storage batteries, these could be recharged electrically. Optionally, these batteries could also be recharged thermally at relatively low temperatures — by use of solar or waste heat, for example. In comparison with thermocouples and thermionic devices, the proposed batteries would generate much greater potentials (about 4 V per cell versus millivolts per thermocouple or thermionic device) and would convert heat to electricity with greater efficiencies.

Posted in: Briefs, Electronics & Computers, Lithium-ion batteries, Lithium-ion batteries, Solar energy, Waste heat utilization

Signal Processor for Doppler Measurements in Icing Research

Short, high-frequency bursts on noisy backgrounds can be processed in real time

An advanced signal processor has been developed to enable high-resolution measurement of the frequency and phase shifts of noisy laser Doppler velocimeter (LDV) and phase Doppler particle analyzer (PDPA) signals. The purpose of the measurements is to exploit the phase Doppler principle to determine the sizes and velocities of droplets entrained in airflows. By enabling such measurements, this signal processor is making it possible to perform ground-breaking research in icing of airplanes and combustion of liquid fuels, involving (1) water-droplet-laden, high-speed airflows that simulate clouds flowing past airplanes and (2) high-speed, dense sprays of liquid fuels, respectively.

Posted in: Briefs, Electronics & Computers, Computational fluid dynamics, Measurements, Lidar, Lidar, Icing and ice detection

Model Optimizes Drying of Wet Sheets

Inefficient drying tunnels waste power, time, and inventory.

Paper, tea, tobacco, and other food and industrial goods use drying tunnels to remove moisture from wet product sheets during manufacture. The tunnels operate using a fan to supply drying air to the product sheet through an orifice plate. Unfortunately, under some supply conditions, little or no drying occurs. However, by running the tunnels under optimized conditions, one drying tunnel can save up to 10% of the cost of power alone. Inventory control benefits can add to the savings. A model has been created that determines the settings necessary to achieve these optimum conditions.

Posted in: Briefs, Software, Optimization, Drying, Manufacturing equipment and machinery

High-Performance POSS-Modified Polymeric Composites

Mass densities will be decreased, while strength, use-temperature range, and radiation resistance will be increased.

Epoxies and/or cyanate esters that incorporate polyhedral oligomeric silsesquioxane (POSS) compounds are undergoing development at Air Force Research Laboratory (AFRL). These formulations are expected to be useful as high-performance matrix resins for advanced, lightweight fiber/matrix composite materials for diverse applications that could include spacecraft structures, automotive structures, prosthetics, sporting goods, and general consumer goods. In comparison with the corresponding unmodified matrix resins and composite materials made with those resins, the POSS-modified resins and composite materials are expected to exhibit lower mass densities, greater stiffness, and capabilities to withstand higher temperatures and higher levels of ionizing radiation.

Posted in: Briefs, TSP, Materials, Composite materials, Resins

Model Simulates Semi-Solid Material Processing

Processing materials in the semi-solid state has many advantages over conventional processing methods.

David Spencer (MIT) developed semi-solid material processing through an accidental observation he made while dealing with the processing of metals in their mushy state. The semi-solid material process basically consists of two stages: pre-processing and processing. During pre-processing, the manufacturer heats the material to a liquid state. While it cools, the manufacturer breaks the material up, usually by mechanical means. The result is a mushy material with a very uniform microstructure consisting mainly of round crystals. Then, in the processing stage, the manufacturer forces the mushy material into a die where it is allowed to fully cool.

Posted in: Briefs, Materials, Simulation and modeling, Casting, Manufacturing processes, Materials properties, Metals

The U.S. Government does not endorse any commercial product, process, or activity identified on this web site.