Test & Measurement

Mass Gauging Demonstrator for Any Gravitational Conditions

This concept uses an optical interferometric method to determine the density and/or pressure of the gas state contained with tank ullage. The system is similar to compression tank volume methods. By using an optical interferometric technique to determine gas density and/or pressure, a much smaller compression volume or higher-fidelity measurement is possible.

Posted in: Briefs, Test & Measurement, Optics, Gases, Test equipment and instrumentation
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Multiport Hat Coupler for Electronically Steerable Antenna Testing

This technology provides the same performance as an anechoic closet, but at two orders of magnitude lower cost.

This invention provides a lower-cost means for verifying the scanning functionality of an electronically steerable (i.e. phased array) antenna (PAA) compared to existing methods that use a scanning probe or scanning test fixture and surrounding anechoic enclosure. This design is comprised of a standard test hat that has been modified to include additional probes located in the positive and negative directions of each scan axis. RF measurements taken from these additional probes provide an estimate of the beam-pointing angle. This solves the problem of verifying the platform-installed antenna’s beam-pointing functionality without the relatively high cost of a conventional anechoic chamber with a scanning probe or scanning test fixture.

Posted in: Briefs, Test & Measurement, Electronic steering control, Antennas
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Neutron Spectrometer for Inner Radiation Belt Studies

The instrument is inherently robust, cost-effective, compact, and modular.

The Earth’s magnetosphere offers a wealth of information on particle dynamics, acceleration, and trapping. Fast neutrons, produced in the Earth’s atmosphere by the impact of galactic cosmic rays (GCRs) and solar energetic particles (SEPs), are an important but poorly measured component of the radiation environment in the inner magnetosphere. Cosmic ray albedo neutron decay (CRAND), whereby atmospheric neutrons beta-decay into protons and electrons, is a significant source of energetic protons in the inner radiation belt. Current models of the inner proton belt rely heavily on Monte Carlo simulations for the CRAND component, validated primarily by a handful of single-point balloon measurements from the 1970s.

Posted in: Briefs, TSP, Test & Measurement, Data acquisition, Data acquisition (obsolete), Satellites
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High-Energy Instrumentation for Small Satellite Platforms

A key asset of the instrument design is the ability to measure a broad range of radiation.

Given the increased availability of small satellite opportunities either through CubeSats or the Air Force’s University Nanosat program, and the limited availability of larger platforms, it is challenging to develop new instrumentation that not only fits within the envelope of small satellites, but also addresses the diverse science applications available in low Earth orbit (LEO). While small-platform instrumentation is limited in sensitivity, the ability to populate LEO with a fleet of instruments opens new science objectives not available with larger standalone payloads. Furthermore, coordinated observations of a variety of radiation species that either enter LEO from the Sun or heliosphere directly, or that reside within the radiation belts themselves, are necessary to fully reach closure on complex processes that govern particle acceleration and transport.

Posted in: Briefs, Test & Measurement, Sensors and actuators, Satellites
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Variable Acceleration Force Calibration System

A variable acceleration calibration system combines an innovative mechanical system and a statistical design of experiments to calibrate multi-axis force transducers. This system can reduce calibration time, allow for improved calibration of large-scale transducers, provide mobility for on-site calibrations, allow multiple transducers to be calibrated simultaneously, and accommodate dynamic force calibration.

Posted in: Briefs, TSP, Test & Measurement, Statistical analysis
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A Synthetic Quadrature Phase Detector/ Demodulator for Fourier Transform Spectrometers

This method makes it possible to use simple, low-cost, high-resolution audio digitizers.

Fourier transform spectroscopy works by measuring a spectral/light signal through a Michelson interferometer. In order to know the wavelength of the signal, one must use a stable reference, which is typically a metrology laser. In a standard Fourier transform spectrometer (FTS) system, the laser signal also runs through the interferometer and the laser beam is guided to a separate detector that is then used to trigger an analog-to-digital converter, which then captures the spectral signal.

Posted in: Briefs, TSP, Test & Measurement, Optics, Data acquisition, Data acquisition (obsolete)
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Device for Direct Measurement of the Diffusivity and Molecular Release Through Membranes and Filters

Controlled-release systems for drug delivery, molecular sieving, and single-molecule detection use micro and nano structures.

Concentration-driven molecular diffusion is a fundamental phenomenon essential for the transport of nutrients in cells, for oxygen exchange in the lungs, and mating of chemicals in industrial reactors and the food industry. Thus, diffusion plays a key role in a variety of disciplines. The concentration-driven diffusive transport is commonly described by Fick’s laws of diffusion. It is most often approximated by the Stokes-Einstein equation, which assumes a rigid solute sphere diffusing in a continuum of solvent at a low Reynolds number and infinite dilution.

Posted in: Briefs, Test & Measurement, Elastomers, Nanomaterials, Test equipment and instrumentation
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An Operationally Based Vision Assessment Simulator for Domes

Applications include remote visualization, flight simulation, virtual environments, and planetariums.

Ames Research Center, Moffett Field, California

The work described here is part of the U.S. Air Force-sponsored Operational Based Vision Assessment (OBVA) program that has been tasked with developing a high-fidelity flight simulation laboratory to determine the relationship between human vision and performance in simulated operationally relevant tasks. The OBVA simulator was designed and built to provide the Air Force School of Aerospace Medicine (USAFSAM) with a scientific testing laboratory to study human vision and testing standards.

Posted in: Briefs, Aeronautics, Computers, Simulation Software, Test & Measurement, Simulation and modeling, Human factors, Test facilities
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Low Er-Doped Yttrium Gallium Garnet (YGG) as Active Media for Solid-State Lasers at 1651 nm

This technology could serve applications in the bio-medical areas such as nerve stimulation and dentistry.

The typical approach for producing laser output at the 1651-nm wavelength is via nonlinear frequency conversion. Lasers based on nonlinear conversion are complex, and it is very difficult to provide stability over time and over a wide range of operating temperatures. The efficiency of such optical sources is also low. A much more promising approach is the use of active media that allows for the development of solid-state lasers (SSL) with spectral emission at 1651 nm. An important requirement for this active medium is the ability to support in-band pumping with a low quantum defect since this approach leads to significant improvement in efficiency of SSLs and excellent beam characteristics due to low thermal stress of the active media.

Posted in: Briefs, TSP, Medical, Lasers & Laser Systems, Instrumentation, Test & Measurement, Medical, health, and wellness
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Dual-Cavity Rayleigh Scattering Measurement System

A method and apparatus were developed for simultaneous measurement of velocity, density, temperature, and their spatial and temporal derivatives in gas flow.

Molecular-based optical diagnostics techniques capable of obtaining simultaneous measurements of multiple fluid properties are critically important for characterizing hypersonic air-breathing engines, such as scramjet engines and scramjet-rocket combined cycle engines. Correlations between those properties lead to a more detailed understanding of complex flow behavior, and aid in the development of multiparameter turbulence models required for supersonic combustion engine flow path predictions.

Posted in: Briefs, TSP, Optics, Instrumentation, Measuring Instruments, Test & Measurement, Optics, Diagnostics, Test equipment and instrumentation
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