Tech Briefs

Development of Automated Structural Health Monitoring for Composite Overwrapped Pressure Vessels

Virtually all NASA spacecraft use composite overwrapped pressure vessels (COPVs) to reduce the weight disadvantage of metal pressure vessels. However, these composite structures are more susceptible to damage than metal PVs, are difficult to inspect, have large burst pressure variability, and are susceptible to stress rupture when maintained at pressure. Over the past few years, NASA's Johnson Space Center (JSC) White Sands Test Facility (WSTF) has developed novel analysis methods that show promise for assessing the structural health of composite overwrapped pressure vessels. These methods and industry standard methods have been integrated into specialized software for automated analysis, thus significantly increasing throughput to the point where real-time assessments of structural health may be determined. Adaptive analysis methods have also been developed to provide modal analyses at specified points in a structure's life, including loading, unloading, and dwells. Together, these enhancements increase the utility and ease of use for acoustic emission testing.

Posted in: Briefs, Software, CAD / CAM / CAE, CAD, CAM, and CAE, Vehicle health management, Composite materials, Spacecraft
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Independent Navigation for the Visually Impaired Using a Wearable, Vision-Based Feedback System

Automatic navigation systems have been developed previously to aid the visually impaired, but these devices have not been as reliable and easy to use as a cane — the type of metal-tipped cane that visually impaired people frequently use to identify clear walking paths. These canes, however, have drawbacks. First, the obstacles they come in contact with are sometimes other people. Second, they can't identify certain types of objects, such as tables or chairs, or determine whether a chair is already occupied.

Posted in: Briefs, Medical, Computer software / hardware, Computer software and hardware, Optics, Computer software / hardware, Computer software and hardware, Optics, Prostheses and implants, Product development
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Interim, In-Situ Additive Manufacturing Inspection

Researchers at NASA's Marshall Space Flight Center have developed a novel method for interim, in-situ dimensional inspection of additively manufactured parts. Additive manufacturing processes currently have limited monitoring capabilities, offering users little to no options for mitigating the high levels of product and process failures.

Posted in: Briefs, Manufacturing & Prototyping, Research and development, Additive manufacturing, Parts, Inspections
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An Electron Caught in the Act

How fast is an electron? Australian scientists were able to measure it. Australia's fastest camera, located at the Attosecond Science Facility, has revealed the time it takes for molecules to break apart. The experimental research, conducted by Griffith University's Centre for Quantum Dynamics, aims to help in the design of new molecules for materials science or drug discovery.

Posted in: Briefs, Photonics
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Scientists Demonstrate New Real-Time Technique for Studying Ionic Liquids at Electrode Interfaces

Ionic liquids—salts made by combining positively charged molecules (cations) and negatively charged molecules (anions) that are liquid at relatively low temperatures, often below room temperature—are increasingly being investigated for uses in batteries, supercapacitors, and transistors. Their unique physical and chemical properties, including good ionic conductivity, low flammability and volatility, and high thermal stability, make them well suited for such applications. But thousands of ionic liquids exist and exactly how they interact with the electrified surfaces of electrodes remains poorly understood, making it difficult to choose one for a particular application.

Posted in: Briefs, Photonics
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Optical Probing Deep into the Eye

Optical coherence tomography (OCT) is a scanning technology commonly used by ophthalmologists to check for eye diseases. A team of scientists has figured out how to retrofit these high-performance machines with off-the-shelf components, increasing OCT's resolution by several-fold, promising earlier detection of retinal and corneal damage, incipient tumors, and more.

Posted in: Briefs, Photonics
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Novel Techniques Examine Solar Cells with Nanoscale Precision

Researchers at the National Institute of Standards and Technology (NIST) have for the first time examined, with nanometer-scale precision, the variations in chemical composition and defects of widely used solar cells. The new techniques, which were used to investigate a common type of solar cell made of the semiconductor material cadmium telluride, promise to aid scientists to better understand the microscopic structure of solar cells and may ultimately suggest ways to boost the efficiency with which they convert sunlight to electricity.

Posted in: Briefs, Photonics
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R&D Effort Produces Magnetic Devices to Enable More Powerful X-ray Lasers

A team of researchers have designed, built, and tested two devices, called superconducting undulators, which could make X-ray free-electron lasers (FELs) more powerful, versatile, compact, and durable.

Posted in: Briefs, Photonics
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2.2-Micron, Uncooled, InGaAs Photodiodes and Balanced Photoreceivers up to 25-GHz Bandwidth

Traditional applications for 2-micron photodetectors have been largely dominated by passive remote sensing where detectors having bandwidth of even one megahertz are deemed sufficient. The onus in such applications is to achieve low dark current through active cooling. The advent of high-power, 2-micron-wavelength lasers has made coherent LiDARs viable for active sensing applications. Such a system needs photodetectors that can handle high local oscillator optical power and have large bandwidth. Through a combination of high coherent gain and small integration time, a large signal-to-noise ratio can be achieved. Operation at high optical power levels reduces the significance of photodiodes' dark current. As a result, uncooled operation at room temperature is feasible, simplifying the overall instrument design.

Posted in: Briefs, Photonics
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PC-Board-Mountable Corrosion Sensors

Corrosion is a pervasive and expensive problem in applications ranging from construction to microelectronics. Corrosion has been widely studied in theories, and empirical studies exist for common materials, material combinations, and myriad environmental conditions. In order for microelectronic devices to perform and function properly, high-reliability packaging is important. Failure of microelectronic devices and packages not only causes a malfunction of the devices themselves, but can lead to catastrophic events for entire systems, which may cause loss of life, property, and safety.

Posted in: Briefs, Sensors
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