Test & Measurement

Strain Gage for Highly Elastic, Low-Modulus Materials

This gage surpasses conventional foil technology, measuring elastic strain range greater than 100 percent while reducing measurement error. Armstrong Flight Research Center, Edwards, California Researchers at NASA’s Armstrong Flight Research Center have developed and tested a new strain gage that makes significant strides in the state of the art, particularly salient given the requirements of new structural components on aerospace vehicles. Conventional foil technology presents a significant shortcoming for these vehicles, since it is limited to less than 20 percent strains while newer vehicles include highly elastic, low-Young’s-modulus materials that require higher strain measurements. For example, fabric-reinforced rubbers and elastomers have a nonlinear stressstrain relationship with extreme rupture strains — some greater than 500 percent.

Posted in: Briefs, Test & Measurement, Elastomers, Materials properties


Considerations for Choosing Temperature Measurement Devices

Temperature is the physical variable most often measured in industrial processes. Selecting the sensor and measurement device to match a specific process is extremely important, and knowing the various options is the first step to optimizing temperature measurement. There are a variety of reasons we need to know the temperature of an object or a process — to prevent product damage, ensure sterilization, determine biological health, ensure mixture blending, control chemical reactions, or ensure drying, curing, and outgassing, to name just a few. Temperature measurement can also be a regulatory requirement; for example, the Food and Drug Administration (FDA) requires temperature monitoring of food and drug products.

Posted in: Articles, Test & Measurement, Measurements, Test equipment and instrumentation, Thermal testing


Improved Detection of Kidney Stones Using S-mode Ultrasound

Steps were developed to improve kidney stone detection relative to surrounding tissue.Ultrasound has been a useful tool in the detection of kidney stones. It is a low-cost solution that does not require ionizing radiation that would be harmful to vulnerable populations such as children and recurrent stone formers. However, it suffers from a broad range of sensitivity (78 to 96%) and specificity (31 to 100%) in the detection of stones.

Posted in: Briefs, Test & Measurement, Imaging and visualization, Children, Diagnosis, Diseases, Medical equipment and supplies


Vector Network Analyzer Calibration for Quasi-Optical Dual Ports

Goddard Space Flight Center, Greenbelt, Maryland It is desirable to measure the electromagnetic properties of devices and materials in the millimeter part of the spectrum. For guided wave-based devices and materials (waveguides, coaxial devices), a vector network analyzer (VNA) is an excellent tool for this purpose since it provides full reflection and transmission characterization at high precision.

Posted in: Briefs, TSP, Test & Measurement, Calibration, Electromagnetic compatibility, Waveguides, Materials properties, Test equipment and instrumentation


Measurement of the Mechanical Properties of Thin Film Polymers at Cryogenic Temperatures

A new apparatus uses pressurized liquid nitrogen to measure deformation. John F. Kennedy Space Center, Florida The measurement of structural properties of materials at cryogenic temperatures is a daunting task. The measurement of thin films at low temperatures is even harder. Current practices of immersing the material in a cryogenic fluid and then removing and testing it does not work due to the rapid warming of the low-mass thin film. Similarly, exposing it to a cold vapor environment, unless well controlled procedurally, does not yield data at a known temperature (the temperature of the material is unknown). Thus, gathering basic material properties of thin film materials at low temperature requires a new approach.

Posted in: Briefs, Test & Measurement, Measurements, Materials properties, Polymers, Test procedures


Estimation of Algae Growth Stage, Growth Rate, and Lipid Content

Applications include diesel fuel production, renewable energy, biofuels, and pharmaceuticals.This invention provides a method using light of different wavelengths to estimate freshwater and marine algae growth stage and algae growth rates as well as lipid content in standard media. Light absorption by the algae is measured for a specified light intensity in each of two or more narrow wavelength ranges, correcting for absorption in the medium without algae. The net light absorption is compared with a reference set of absorption values for the algae at different growth stages.

Posted in: Briefs, Test & Measurement, Measurements, Biomaterials, Materials properties, Test procedures, Marine vehicles and equipment


Isotopic Biomarkers for Rapid Assessment of Bone Mineral Balance in Biomedical Applications

Advanced isotope tracer techniques are explored. Lyndon B. Johnson Space Center, Houston, Texas Development of new treatments for metabolic bone disease, and evaluation of the effectiveness of existing therapies in individual patients, are severely hampered by the lack of any reliable tool for quickly measuring changes in bone mineral balance in response to treatment. A new tracerless calcium isotope biomarker of bone mineral balance fills this need. When properly applied, the calcium isotope biomarker reveals changes in bone mineral balance with unprecedented speed and detail, and has the potential to dramatically improve the treatment for diseases such as osteoporosis. A complementary strontium isotope biomarker provides, with equal rapidity, information on the speed of exchange of calcium between soft tissue and mineralized compartments.

Posted in: Briefs, Test & Measurement, Measurements, Biological sciences, Diseases, Medical equipment and supplies, Calcium


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