Test & Measurement

Reliability Testing of High-Power Devices

Before a new high-power semiconductor device can be used for industrial applications, it must be thoroughly tested to determine if it will survive environmental stresses and continue to meet specifications. This is especially true for the latest wide-bandgap semiconductor materials such as silicon carbide (SiC) and gallium nitride (GaN) to ensure they can withstand high voltage and temperatures.

Posted in: Briefs, Test & Measurement, High voltage systems, Semiconductors, Reliability, Test procedures, Thermal testing
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Electronic Device Monitors the Heart and Recognizes Speech

Researchers from the University of Colorado Boulder and Northwestern University have developed a tiny, soft, and wearable acoustic sensor that measures vibrations in the human body, allowing them to monitor human heart health and recognize spoken words. The stretchable device captures physiological sound signals from the body, has physical properties matched with human skin, and can be mounted on nearly any surface of the body. The sensor resembles a small Band-Aid®, weighs less than one-hundredth of an ounce, and can gather continuous physiological data.

Posted in: Briefs, Test & Measurement, Measurements, Cardiovascular system, Prostheses and implants, Acoustics, Vibration
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Split Laser System for Environmental Monitoring

Environmental monitoring — the assessment of air, water, and soil quality — is highly important to oil and gas exploration companies, landowners, regulatory agencies, municipalities, and any organization measuring emissions and pollutants. The majority of monitoring technologies, however, are expensive and labor intensive, often requiring sample collection and preparation (i.e., external lab analysis) that can dramatically alter the sample and its inherent components. Of those technologies that do allow for in-situ analysis, few are amenable to measurements under harsh conditions, such as high temperature and/or pressure.

Posted in: Briefs, Test & Measurement, Lasers, Environmental testing, Test equipment and instrumentation, Test procedures
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Measuring Tiny Forces with Light

Photons have no mass, but they have momentum. This allows researchers to use light to push matter around. Scientists at the Physical Measurement Laboratory (PML) at the National Institute of Standards and Technology (NIST) have taken advantage of this property to develop devices that can create and measure minute forces, an area traditionally underserved by the metrology community.

Posted in: Briefs, Test & Measurement, Measurements, Materials properties, Test equipment and instrumentation, Test procedures
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Laser Scanning Technique for Testing Fire-Damaged Concrete

Research at The University of Nottingham (UK) and the University at Ningbo (China) has found that laser scanning is a viable structural safety technique to detect the damaging effects of fire on concrete. Concrete is the most extensively used construction material worldwide with an average global yearly consumption of 1 cubic meter per person. Fire is one of the most serious potential risks to concrete structures such as bridges, tunnels, and buildings.

Posted in: Briefs, Test & Measurement, Lasers, Materials properties, Fire, Risk assessments, Safety testing and procedures
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3D Measurement and Visualization of Displacement and Strain Fields

The Naval Research Laboratory (NRL) has developed a metrology workbench for the measurement and visualization of displacement and strain fields in three dimensions. The workbench uses two or more cameras to image a specimen, and includes custom software that implements the 3D Meshless Random Grid method.

Posted in: Briefs, Test & Measurement, Finite element analysis, Computer software and hardware, Optics, Test equipment and instrumentation
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Eddy Current Probe for Surface and Sub-Surface Inspection

This technology can be used in aerospace, manufacturing, materials, and energy applications.

NASA's Langley Research Center has developed a novel probe for eddy current sensor applications that improves detection depth and measurement resolution. Although the use of anisotropic magnetoresistive (AMR) sensors in eddy current probes to improve sensitivity at low frequencies and increase the detection depth is known, the high-frequency sensitivity and small size of these sensors is less explored. This new probe incorporates two induction sources (i.e., one high-frequency and one low-frequency) and an AMR sensor; the result is improved resolution in near-surface material characterization, combined with simultaneous deep-flaw detection. Addition of a second high-frequency induction source, oriented to produce a magnetic field orthogonal to the first, allows for near-surface anomaly detection in two dimensions.

Posted in: Briefs, Sensors, Measuring Instruments, Test & Measurement, Computational fluid dynamics, Sensors and actuators, Inspections
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Variably Transmittive, Electronically Controlled Eyewear

This technology can be used in pilot glasses, military goggles, gaming and virtual reality, and transition lenses for eyewear.

During instrument flight training, the pilot must have his/her view through the aircraft windscreen restricted to simulate low-visibility conditions while permitting the pilot to view the instrument panel. In one current method, a hood is draped across the aircraft windscreen, or a face mask or blackened glasses are worn by the pilot. All such current methods create potentially hazardous disorientation and an unnatural environment for the trainee. In particular, the face mask and blackened glasses restrict the pilot’s peripheral vision, and require uncomfortable and unnatural head positions in order to see the entire instrument panel.

Posted in: Briefs, Instrumentation, Simulation and modeling, Electronic control units, Displays, Visibility
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Method for Ground-to-Satellite Laser Calibration System

NASA’s Langley Research Center has developed the Ground-to-Space Laser Calibration (GSLC) system concept for calibrating Earth observing sensors measuring reflected radiance. GSLC is capable of calibrating sensitivity to polarization, degradation of optics, and response to stray light of spaceborne reflected solar sensors. The concept is based on using an accurate ground-based laser system pointing at and tracking the instrument on orbit during nighttime and clear atmosphere conditions. The GSLC system will be applicable to instrument calibration in both low Earth and geostationary Earth orbits.

Posted in: Briefs, Instrumentation, Calibration, Lasers, Satellite communications
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Energy Analysis Method for Hidden Damage Detection

Better understanding of composite damage could eliminate unnecessary repairs and help prevent catastrophic in-service failure.

NASA’s Langley Research Center has developed a new Non-Destructive Testing (NDT) method for identifying and characterizing hidden damage in composite materials. The new technique requires only single-sided access to the test specimen, and uses trapped energy analysis to detect and characterize damage that was previously ob - scured. Current methods, usually ultrasound or laser ultrasound, cannot characterize imperfections below or hidden by near surface damage. The new method uses 3D custom ultrasonic simulation tools to study ultrasonic guided wave behavior and energy trapping due to multilayer delamination damage (Figure 1).

Posted in: Briefs, Instrumentation, Imaging and visualization, Composite materials, Non-destructive tests
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