Tech Briefs

Stationary Apparatus Would Apply Forces of Walking to Feet

The forces would be tailored to prevent loss of bone density.A proposed apparatus would apply controlled cyclic forces to both feet for the purpose of preventing the loss of bone density in a human subject whose bones are not subjected daily to the mechanical loads of normal activity in normal Earth gravitation. The apparatus was conceived for use by astronauts on long missions in outer space; it could also be used by bedridden patients on Earth, including patients too weak to generate the necessary forces by their own efforts.

Posted in: Briefs, TSP, Bio-Medical, Medical, Anatomy, Medical, health, and wellness, Personnel, Biomechanics

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Instrument Would Detect and Collect Biological Aerosols

Samples would be quickly collected on substrates that would be analyzed automatically.A proposed compact, portable instrument would sample micron-sized airborne particles, would discriminate between biological ones (e.g., bacteria) and nonbiological ones (e.g., dust particles), and would collect the detected biological particles for further analysis. The instrument is intended to satisfy a growing need for means of rapid, inexpensive collection of bioaerosols in a variety of indoor and outdoor settings. Purposes that could be served by such collection include detecting airborne pathogens inside buildings and their ventilation systems, measuring concentrations of airborne biological contaminants around municipal waste-processing facilities, monitoring airborne effluents from suspected biowarfare facilities, and warning of the presence of airborne biowarfare agents.

Posted in: Briefs, Bio-Medical, Medical, Biomaterials, Gases, Test equipment and instrumentation

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Generating Control Commands From Gestures Sensed by EMG

Electrical signals from muscles involved in gestures are recognized.An effort is under way to develop noninvasive neuro-electric interfaces through which human operators could control systems as diverse as simple mechanical devices, computers, aircraft, and even spacecraft. The basic idea is to use electrodes on the surface of the skin to acquire electromyographic (EMG) signals associated with gestures, digitize and process the EMG signals to recognize the gestures, and generate digital commands to perform the actions signified by the gestures.

Posted in: Briefs, TSP, Bio-Medical, Medical

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Optically Driven Deformable Mirrors

There is no wiring on the back sides of these mirrors. A contOptically driven deformable mirrors may eventually supplant electrically driven deformable mirrors in some adaptive-optics and active-optics applications. Traditionally, the mirror facets in electrically driven deformable mirrors are actuated, variously, by means of piezoelectric, electrostrictive, microelectromechanical, liquid-crystal, or thermal devices. At least one such device must be dedicated to each facet, and there must be at least one wire carrying a control or drive signal to the device. If a deformable mirror comprises many (e.g., thousands) of facets, then wiring becomes a major problem for design, and the problem is compounded in cases of piezoelectric or other actuators for which high drive voltages are required. In contrast, in optically driven mirrors, the wiring problem is eliminated.

Posted in: Briefs, TSP, Electronics & Computers

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Multiple-Flat-Panel System Displays Multidimensional Data

Related images are displayed simultaneously to facilitate perception of trends in data. The NASA Ames hyperwall is a display system designed to facilitate the visualization of sets of multivariate and multidimensional data like those generated in complex engineering and scientific computations. The hyperwall includes a 77 matrix of computer-driven flat-panel video display units, each presenting an image of 1,280×1,024 pixels. The term “hyperwall” reflects the fact that this system is a more capable successor to prior computer-driven multiple-flat-panel display systems known by names that include the generic term “powerwall” and the trade names PowerWall” and “Powerwall.”

Posted in: Briefs, Electronics & Computers

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Probe Station and Near-Field Scanner for Testing Antennas

Multiple antennas on the same substrate can be evaluated quickly and inexpensively. A facility that includes a probe station and a scanning open-ended waveguide probe for measuring near electromagnetic fields (see figure) has been added to Glen Research Center’s suite of antenna-testing facilities, at a small fraction of the cost of the other facilities. This facility is designed specifically for nondestructive characterization of the radiation patterns of miniaturized microwave antennas fabricated on semiconductor and dielectric wafer substrates, including active antennas that are difficult to test in traditional antenna-testing ranges because of fragility, smallness, or severity of DC-bias or test-fixture requirements. By virtue of the simple fact that a greater fraction of radiated power can be captured in a near-field measurement than in a conventional far-field measurement, this near-field facility is convenient for testing miniaturized antennas with low gains.

Posted in: Briefs, Electronics & Computers

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Automatic Alignment of Displacement-Measuring Interferometer

Corrections are derived from fluctuations associated with circular dithering of a laser beam. A control system strives to maintain the correct alignment of a laser beam in an interferometer dedicated to measuring the displacement or distance between two fiducial corner-cube reflectors. The correct alignment of the laser beam is parallel to the line between the corner points of the corner-cube reflectors: Any deviation from parallelism changes the length of the optical path between the reflectors, thereby introducing a displacement or distance measurement error.

Posted in: Briefs, TSP, Electronics & Computers

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