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The technology is part of a new generation of NASA Glenn SiC integrated circuits with unprecedented durability in the field of high-temperature electronics. For robust operational amplifiers based on SiC Junction Field Effect Transistors (JFETs), this novel compensation method mitigates issues with threshold voltage variations that are an effect of die location on the wafer. Modern high-temperature op amps on the market fall short due to temperature limits (only 225C for silicon-based devices). Previously, researchers noted that multiple op amps on a single SiC wafer had different amplification properties due to different threshold voltages that varied spatially as much as 18&#37 depending on the circuit's distance from the SiC wafer center. While 18&#37 is okay for some applications, other important system applications demand better precision. By applying this technology to the amplifier circuit design process, the op amp will provide the same signal gain no matter its position on the wafer. The compensation approach enables practical signal conditioning that works from 25C up to 500C.

Armstrong has developed a robust fiber optic&#8211;based sensing technology that offers extraordinary accuracy in liquid level measurements. The sensing system uses fiber optic Bragg sensors located along a single fiber optic cable. These sensors actively discern between the liquid and gas states along a continuous fiber and can accurately pinpoint the liquid level. <strong><i>How It Works</strong></i> The technology uses a resistive heater wire bundled with the optical fiber. The heater is pulsed to induce a local temperature change along the fiber, and the fiber Bragg grating data is used to monitor the subsequent cooling of the fiber. The length of fiber in the liquid cools more rapidly than the portion of the fiber in the gas above the liquid. The measurement system accurately establishes the location of this transition to within 1/4-inch. <strong><i>Why It Is Better</strong></i> Armstrong's liquid level sensing technology was originally developed to measure cryogenic liquid levels in rockets, and it represents a significant advancement in the state of the art in this application. Conventional methods for measuring cryogenic liquid levels rely on cryogenic diodes strategically placed along a rod or rack. The diodes are mounted in pre-selected, relatively widely spaced positions along the length of a rod; this configuration provides limited, imprecise data. Furthermore, each diode on the rod has two wires associated with it, which means a single system may require a large number of wires, making installation, connectivity, and instrumentation cumbersome. Armstrong's novel technology provides liquid measurements with much greater precision, achieving measurements at 1/4-inch intervals. Furthermore, the streamlined system uses just two wires, which greatly simplifies installation and instrumentation. Due to its extraordinary accuracy and ease of use, Armstrong's measurement system offers important advantages for a wide range of applications beyond cryogenic liquids. <strong><i>In Addition</strong></i> Researchers have developed a new manufacturing process that improves the ability of fiber optic sensing systems to measure temperature and liquid levels when operating in humid environments. The process involves eliminating moisture from the optical fiber coating, then completing the sensor assembly within humidity-controlled conditions. The resulting sensor hardware provides precise and accurate measurements even when operating in a humid environment. <b><i>For more information about the full portfolio of FOSS technologies, see DRC-TOPS-37 or visit&nbsp;<a href=https://technology-afrc.ndc.nasa.gov/featurestory/fiber-optic-sensing>https://technology-afrc.ndc.nasa.gov/featurestory/fiber-optic-sensing</a></b></i>

The VARR valve has been designed to provide a variable-size aperture that proportionately changes in relation to gas flow demand. When the pressure delta between two chambers is low, the effective aperture cross-sectional area is small, while at high delta pressure the effective aperture cross-sectional area is large. This variable aperture prevents overly restricted gas flow. As shown in the drawing below, gas flow through the VARR valve is not one way. Gas flow can traverse through the device in a back-and-forth reversing flow manner or be used in a single flow direction manner. The contour shapes and spacing can be set to create a linear delta pressure vs. flow rate or other pressure functions not enabled by current standard orifices. Also, the device can be tuned to operate as a flow meter over an extremely large flow range as compared to fixed-orifice meters. As a meter, the device is capable of matching or exceeding the turbine meter ratio of 150:1 without possessing the many mechanical failure modes associated with turbine bearings, blades, and friction, etc.