November 1998

Briefs : Electronics & Computers
Ferroelectric Electronic Scan Antennas

Most current radar scanning antennas utilize mechanical scanning, relying on a gimbal, motor, and gear arrangements to physically rotate/elevate the antenna. This technique is slow, gravity-sensitive, and susceptible to shock and mechanical failure. High-speed multiple target tracking cannot be effectively...

Briefs : Electronics & Computers
Improved Tuning of a Microwave Cavity for Heating Samples

A technique for adjusting the resonance frequency of a single-mode round cylindrical microwave cavity has been proposed to maximize the transfer of power from a magnetron to one or more sample(s) of material that have been placed in the cavity for microwave heating. Unlike an older...

Briefs : Software
Program Computes Flightpaths From Point Radar Sightings

A computer program estimates great-circle-arc (GARC) flightpaths of multiple aircraft, given time-tagged point locations from radar sightings of the aircraft. The problem of generating such estimates is called a "clustering" problem, and is solved in this instance by use of a...

Briefs : Test & Measurement
Noncontact Measurement of Surface Tension of Molten Material

An improved method of noncontact measurement of the surface tension of a molten material has been developed, partly to overcome the disadvantages of contact measurement techniques as described in the preceding article, "Noncontact Measurement of Resistivity of Molten Material"...

Briefs : Test & Measurement
Measuring Temperature of Glass by Multiwavelength Pyrometry

A multiwavelength pyrometric technique estimates the surface and bulk (subsurface) temperatures of a hot glass. The multiwavelength pyrometer for which the technique was developed comprises a spectrometer plus a computer. The spectrometer can be operated in any of three wavelength...

Briefs : Robotics, Automation & Control
Collision-Avoidance Experiments on 7-DOF Robot Arms

A report describes experiments on the concept described in "Real-Time Collision Avoidance for a Robot Arm" (NPO-19861), NASA Tech Briefs, Vol. 20, No. 12 (December 1996), page 98. Under this concept, collision-avoidance software processes data computed by model-based obstacle-detection...

Briefs : Electronics & Computers
Laser-Based Instrument Measures Vibration at a Single Point

Sponsored by a NASA Small Business Innovation Research (SBIR) Phase II contract, MetroLaser, Inc., has developed a novel, compact and low-cost laser Doppler vibrometer (LDV) under the brand name VibroMet. This LDV is a turnkey system for noncontact measurement of vibration at a single...

Briefs : Physical Sciences
Illumination Device for Inspecting Window Surfaces

A special-purpose fiber-optic illumination device can be attached temporarily to a window to help an inspector examine window surfaces for scratches, pits, small-scale roughness, and dirt. This device was developed to replace an older fiber-optic illumination device that provided intense...

Briefs : Electronics & Computers
Micromachined Photodiode/Bolometer Arrays

Micromachined planar arrays of detectors that could operate either as photodiodes or as bolometers have been proposed for use in detecting photons in applications in which broad spectral responses are required. The availability of either of the two modes would enable operation throughout the spectrum,...

Briefs : Test & Measurement
Noncontact Measurement of Resistivity of Molten Material

It is now possible to determine the electrical resistivity of a molten sample of a pure, electrically conductive material (a metal or semiconductor), without contact between the sample or any solid object. Once the electrical resistivity has been determined, the thermal conductivity can...

Briefs : Electronics & Computers
First-Generation "Space Cube" Electronic-Circuit Packaging

The term "space cube" denotes a scheme for three-dimensional stacking and interconnection of electronic-circuit modules. [This scheme should not be confused with a related one described in "Stackable Electronic Computer Modules and Interconnections" (NPO-19521), NASA Tech Briefs, Vol....

Briefs : Test & Measurement
Advanced Measurement of Angle of Attack and Sideslip

Nearly every military and commercial aircraft in the United States today uses pitot-static probes for accurate, repeatable airdata measurements. Recently, local angle-of-attack- and sideslip-sensing capabilities have been added to these probes to satisfy requirements for advanced aircraft...

Briefs : Mechanical & Fluid Systems
Estimating Attitude of a Robotic Balloon From Accelerations

An improved "sensor-integrating" algorithm has been developed for use in extracting partial information on the time-varying attitude of a balloon-borne robotic instrumentation system from the outputs of accelerometers that measure accelerations along three Cartesian axes fixed in the...

Briefs : Electronics & Computers
Improved Electron-Tunneling Magnetometer

Efforts are underway to develop an electron-tunneling magnetometer with a "planarized" (as explained below) design. Older designs of electron-tunneling magnetometers are more three-dimensional in character and, as such, entail some difficulties of fabrication. [Such an older design was described in...

Briefs : Test & Measurement
Micromachined Force-Balance Anemometer

A micromachined force-balance anemometer has been developed by modifying the design of a micromachined force-balance accelerometer that responds to accelerations as small as 109 × normal Earth gravitation (about 10 - 8 m/s2). The anemometer thus offers the advantages of...

Briefs : Test & Measurement
Software for Automated Retesting of Electrical Connections

The Shuttle Connector Analysis Network Automated Electrical Retest Operations (SCAN/AERO) computer program assists in the tracking, management, and automation of the retesting of electrical connectors on the space shuttle orbiters. Among other things, SCAN/AERO analyzes test data to...

Briefs : Materials
Acid/Base Sensors Based on Poly(aromatic amine) Films

Chemiresistors containing poly(aromatic amine) films have been invented to satisfy a need for simple, inexpensive sensors for real-time measurement of parts-per-million and possibly lower concentrations of acidic and basic gases in air. These sensors could also be used to measure...

Briefs : Materials
Improved Anode Design of Rechargeable Li-Ion Cells

Several modifications of the basic design of carbon lithium-intercalating anodes with copper current collectors in rechargeable lithium-ion electrochemical cells have been proposed. These modifications are intended to prevent or at least retard the internal short-circuiting and consequent...

Briefs : Robotics, Automation & Control
Update on System for Robot-Assisted Microsurgery

Two reports present updated information on a robotic system that extends the dexterity of a microsurgeon. The system was described in two articles in NASA Tech Briefs, Vol. 21, No. 10 (October 1997); namely, "Telerobot Control for Microsurgery" (NPO-19823), on page 46 and "Force-Feedback Device...

Briefs : Software
Program for Conceptual Design of an Attitude-Control System

A report describes the ACS Design Tool - a Macintosh- and PC-based computer program for evaluating conceptual designs of a spacecraft attitude-control system (ACS) within a computation time of about 15 minutes. Services provided by the program include computation of ACS performance...

Briefs : Electronics & Computers
Multiple-Beam Transmission for Optical Communication

Multiple-beam transmission has been proposed to reduce the deleterious effects of atmospheric turbulence on free-space laser communications - especially on uplinks from ground stations to Earth-orbiting satellites. The deleterious effects in question are signal fades and surges associated with...

Briefs : Robotics, Automation & Control
Swivel-Head Sampling Drill Bit

A swivel-head drill bit has been invented for use in acquiring a sample of a possibly hard material at a predetermined depth. This mechanism is a simpler and thus potentially cheaper alternative to deep-coring and sampling mechanisms that contain secondary actuators to open doors and/or to drive internal sampling...

Briefs : Test & Measurement
Apparatus for Measuring a Weak Induced Magnetic Field

The figure illustrates an apparatus for inducing an electric current in an electrically conductive object or layer of material and measuring the magnetic field generated by the current (that is, the induced magnetic field) to obtain information about the object or layer. The apparatus can be...

Briefs : Electronics & Computers
Compact Bit-Serial VLSI Neuroprocessor for Automotive Use

An application-specific integrated circuit (ASIC) has been developed as a prototype of neuroprocessors for real-time diagnosis and control of automotive engines. The application of this ASIC was previously reported in "Neuroprocessor for Detecting Misfire in an Automotive Engine"...

Briefs : Materials
Progress in Texturing by Use of Monatomic Oxygen

A report presents findings from recent research on the use of monatomic oxygen to form microscopic textures on the surfaces of polymers and extends the concept to some forms of carbon. Earlier developments in this field were described in two articles in NASA Tech Briefs, Vol. 20, No. 11 (November...

Briefs : Test & Measurement
Silicon Micromachined Accelerometer/Seismometer

The figure illustrates a silicon micromachined accelerometer currently under development that is designed specifically for seismologic applications. The device is designed for a sensitivity of 1 ng/Hz1/2 (where g denotes the Earth's gravitational acceleration, i.e., 9.81...

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