Special Coverage

Supercomputer Cooling System Uses Refrigerant to Replace Water
Computer Chips Calculate and Store in an Integrated Unit
Electron-to-Photon Communication for Quantum Computing
Mechanoresponsive Healing Polymers
Variable Permeability Magnetometer Systems and Methods for Aerospace Applications
Evaluation Standard for Robotic Research
Small Robot Has Outstanding Vertical Agility
Smart Optical Material Characterization System and Method
Lightweight, Flexible Thermal Protection System for Fire Protection

Surface Micromachined Silicon Carbide Accelerometers

These accelerometers could be valuable for diagnosis of engines. Surface micromachined silicon carbide accelerometers are undergoing development for eventual use in high-temperature environments like those inside turbines, internal-combustion engines, and other machines. These accelerometers would be used to measure vibrations indicative of deterioration of mechanical components; as such, they would be valuable diagnostic tools that could give advance warnings of failures or for the need to perform maintenance. They would even be small enough to fit into turbine blades.

Posted in: Briefs, TSP, Mechanical Components, Mechanics, Sensors and actuators, Diagnostics, Heat resistant alloys, Silicon alloys, Vibration


Software for Predicting Behavior of a Pyrotechnic Actuator

This software has remedied conceptual errors in some prior design models.A theoretical model that predicts the time-dependent behavior of a pyrotechnically actuated mechanism and a computer program that implements the model have been developed. The model and program are especially applicable to a pyrotechnic device known as the NASA Standard Initiator (NSI). Before this model and program were developed, the only principles that guided the design of pyrotechnically actuated mechanisms were those derived through empiricism.

Posted in: Briefs, TSP, Physical Sciences, Finite element analysis, Computer software and hardware, Sensors and actuators, Fire


Dither Sensing for Controlling a Segmented-Mirror Telescope

Images of distant point sources are processed to obtain wavefront-correction control signals.Image-plane multidither sensing has been found to be suitable for adaptive wavefront correction in a large telescope in which the main optic is a precise reflector divided into lightweight, controllably actuated segments. In image-plane multidither sensing, the telescope is aimed at a star or other distant point source and image data are recorded as each segment in turn is dithered slightly about a nominal position and orientation. The image data are processed into actuator-control signals for adjusting the nominal segment positions and orientations to obtain the desired wavefront correction.

Posted in: Briefs, Physical Sciences, Optics, Sensors and actuators, Waveguides


Self-Temperature-Compensated Ceramic Strain Gauges

External temperature-compensation circuits are not needed.Ceramic static-strain gauges capable of generating mechanical-strain signals much larger than spurious thermal signals have been invented. These gauges are intended for use at temperatures from room temperature to 1,250 °C. Heretofore, external circuits have been used to provide temperature compensation for (that is, to correct for or suppress the spurious signals of) strain gauges. No such external temperature-compensation circuits are needed for temperature compensation of the present developmental strain gauges.

Posted in: Briefs, Physical Sciences, Measurements, Ceramics, Heat resistant materials, Test equipment and instrumentation


"Set and Hold With Power Off" Cryogenic Actuators

Magnetic fields would be applied to magnetostrictive rods by high-temperature-superconductor electromagnets.Magnetostrictive actuators that would hold their displacements with power turned off have been proposed for use at temperatures from about 10 to about 77 K. Such "set and hold with power off" actuators are attractive for effecting fine position adjustments in cryogenic scientific instruments, wherein significant amounts of heat would be released and could disturb instrument operation if it were necessary to apply power continually to maintain actuator displacements.

Posted in: Briefs, TSP, Physical Sciences, Capacitors, Sensors and actuators, Switches


Electrobiotic Toxic-Agent Sensors

Inexpensive, compact, reliable sensors would be easy to use.Electrobiotic sensors have been proposed for detecting toxic substances in a variety of environments. Electrobiotic sensors would be inexpensive, compact units that would be easy to use and could be deployed either singly or in large numbers, depending on the size of an environment to be monitored and/or the need to locate a toxic source within a larger area. For example, multiple electrobiotic sensors might be deployed on a battlefield or at a large-scale mining operation, whereas a single electrobiotic sensor might be used to monitor the air in a laboratory or at an assembly bench where toxic chemicals are used.

Posted in: Briefs, TSP, Electronics & Computers, Sensors and actuators, Product development, Hazardous materials


Magnetoelectric Sensors and Electric Generators

Novel applications of the magnetoelectric effect are proposed.Electric generators and magnetic-field sensors of a proposed type would be based on the magnetoelectric effect. A simple device of this type (see figure) would consist mainly of an inner layer of a magnetoelectric material sandwiched between two outer layers of a ferromagnetic material. Electrical contacts would be placed at opposite ends of the magnetoelectric material.

Posted in: Briefs, TSP, Electronics & Computers, Electromagnetic compatibility, Sensors and actuators, Magnetic materials, Electric motors


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