938 research outputs found

    The NASA SBIR product catalog

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    The purpose of this catalog is to assist small business firms in making the community aware of products emerging from their efforts in the Small Business Innovation Research (SBIR) program. It contains descriptions of some products that have advanced into Phase 3 and others that are identified as prospective products. Both lists of products in this catalog are based on information supplied by NASA SBIR contractors in responding to an invitation to be represented in this document. Generally, all products suggested by the small firms were included in order to meet the goals of information exchange for SBIR results. Of the 444 SBIR contractors NASA queried, 137 provided information on 219 products. The catalog presents the product information in the technology areas listed in the table of contents. Within each area, the products are listed in alphabetical order by product name and are given identifying numbers. Also included is an alphabetical listing of the companies that have products described. This listing cross-references the product list and provides information on the business activity of each firm. In addition, there are three indexes: one a list of firms by states, one that lists the products according to NASA Centers that managed the SBIR projects, and one that lists the products by the relevant Technical Topics utilized in NASA's annual program solicitation under which each SBIR project was selected

    Surface Acoustic Wave (saw) Cryogenic Liquid And Hydrogen Gas Sensors

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    This research was born from NASA Kennedy Space Center’s (KSC) need for passive, wireless and individually distinguishable cryogenic liquid and H2 gas sensors in various facilities. The risks of catastrophic accidents, associated with the storage and use of cryogenic fluids may be minimized by constant monitoring. Accidents involving the release of H2 gas or LH2 were responsible for 81% of total accidents in the aerospace industry. These problems may be mitigated by the implementation of a passive (or low-power), wireless, gas detection system, which continuously monitors multiple nodes and reports temperature and H2 gas presence. Passive, wireless, cryogenic liquid level and hydrogen (H2) gas sensors were developed on a platform technology called Orthogonal Frequency Coded (OFC) surface acoustic wave (SAW) radio frequency identification (RFID) tag sensors. The OFC-SAW was shown to be mechanically resistant to failure due to thermal shock from repeated cycles between room to liquid nitrogen temperature. This suggests that these tags are ideal for integration into cryogenic Dewar environments for the purposes of cryogenic liquid level detection. Three OFC-SAW H2 gas sensors were simultaneously wirelessly interrogated while being exposed to various flow rates of H2 gas. Rapid H2 detection was achieved for flow rates as low as 1ccm of a 2% H2, 98% N2 mixture. A novel method and theory to extract the electrical and mechanical properties of a semiconducting and high conductivity thin-film using SAW amplitude and velocity dispersion measurements were also developed. The SAW device was shown to be a useful tool in analysis and characterization of ultrathin and thin films and physical phenomena such as gas adsorption and desorption mechanisms

    Artificial Neural Network and Wavelet Features Extraction Applications in Nitrate and Sulphate Water Contamination Estimation

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    This work expounds the review of non-destructive evaluation using near-field sensors and its application in environmental monitoring. Star array configuration of planar electromagnetic sensor is explained in this work for nitrate and sulphate detection in water. The experimental results show that the star array planar electromagnetic sensor was able to detect nitrate and sulphate at different concentrations. Artificial Neural Networks (ANN) is used to classify different levels of nitrate and sulphate contaminations in water sources. The star array planar electromagnetic sensors were subjected to different water samples contaminated by nitrate and sulphate. Classification using Wavelet Transform (WT) was applied to extract the output signals features. These features were fed to ANN consequently, for the classification of different levels of nitrate and sulphate concentration in water. The model is capable of distinguishing the concentration level in the presence of other types of contamination with a root mean square error (RMSE) of 0.0132 or 98.68% accuracy

    2020 NASA Technology Taxonomy

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    This document is an update (new photos used) of the PDF version of the 2020 NASA Technology Taxonomy that will be available to download on the OCT Public Website. The updated 2020 NASA Technology Taxonomy, or "technology dictionary", uses a technology discipline based approach that realigns like-technologies independent of their application within the NASA mission portfolio. This tool is meant to serve as a common technology discipline-based communication tool across the agency and with its partners in other government agencies, academia, industry, and across the world

    Microwave Acoustic SAW Resonators for Stable High-temperature Harsh-Environment Static and Dynamic Strain Sensing Applications

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    High-temperature, harsh-environment static and dynamic strain sensors are needed for industrial process monitoring and control, fault detection, structural health monitoring in power plant environments, steel and refractory material manufacturing, aerospace, and defense applications. Sensor operation in the aforementioned extreme environments require robust devices capable of sustaining the targeted high temperatures, while maintaining a stable sensor response. Current technologies face challenges regarding device or system size, complexity, operational temperature, or stability. Surface acoustic wave (SAW) sensor technology using high temperature capable piezoelectric substrates and thin film technology has favorable properties such as robustness; miniature size; capability of mass production; reduced installation costs; battery-free operation; maintenance-free; and offer the potential for wireless, multi-sensor interrogation. These characteristics are very attractive for static and dynamic strain sensors targeted to operate in high-temperature harsh-environment conditions. The investigation of harsh-environment static and dynamic SAW strain sensors requires addressing the issues of: (i) sensor platform endurance and stability; (ii) development of durable packaging and attachment techniques; (iii) temperature compensation techniques, to mitigate temperature cross-sensing; and (iv) methods of sensor interrogation and calibration at high temperatures. In this work, langasite-based SAW resonator (SAWR) sensors have been investigated. A stable sensor platform was verified for two types of thin-film electrode configurations, namely: co-deposited Pt/Al2O3 (up to 750oC) and multilayered PtNi|PtZr (up to 1000oC). High-temperature sensor attachment solutions for strain sensor applications were developed for temperatures up to 500oC. The developed SAWR sensors were tested and calibrated for both static and dynamic strain up to 400oC. A temperature compensation technique and a novel finite element analysis was used to perform high-temperature static strain calibration. A high-temperature dynamic strain test rig using a constant stress beam was designed, implemented and used to characterize the SAWR strain sensor performance in measuring dynamic strain. Using the in-phase and quadrature strain sensor signal analysis technique proposed and developed in this study, the existence of both amplitude and frequency modulations of the SAWR RF signal by the dynamic strain signal was confirmed, and the two types of modulations separated and quantified

    Review: optical fiber sensors for civil engineering applications

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    Optical fiber sensor (OFS) technologies have developed rapidly over the last few decades, and various types of OFS have found practical applications in the field of civil engineering. In this paper, which is resulting from the work of the RILEM technical committee “Optical fiber sensors for civil engineering applications”, different kinds of sensing techniques, including change of light intensity, interferometry, fiber Bragg grating, adsorption measurement and distributed sensing, are briefly reviewed to introduce the basic sensing principles. Then, the applications of OFS in highway structures, building structures, geotechnical structures, pipelines as well as cables monitoring are described, with focus on sensor design, installation technique and sensor performance. It is believed that the State-of-the-Art review is helpful to engineers considering the use of OFS in their projects, and can facilitate the wider application of OFS technologies in construction industry

    Plasma-Assisted Growth and Characterization of Piezoelectric AlN and Sc(x)Al(1-x)N Films for Microwave Acoustic Sensor Applications

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    The use of surface acoustic wave (SAW) sensors in high temperature harsh environments such as those found in power plants, industrial manufacturing, or aerospace applications allows for monitoring of internal conditions at locations where traditional sensors do not operate or are unreliable. Surface acoustic wave resonator (SAWR) sensors are based on piezoelectric materials and feature a small passive low-profile self-powered design that can operate and wirelessly transmit data to monitor parameters such as temperature, pressure, or strain. SAWR sensors typically consist of a series of metal electrodes fabricated onto a bulk crystal piezoelectric such as langasite (La3Ga5SiO14). However, there are major advantages in using thin film piezoelectrics such as AlN and ScxAl1-xN rather than bulk single crystal piezoelectrics, including the ability to fabricate devices on a wider range of substrates allowing for greater tuning of devices properties. This thesis investigates the film growth, materials characterization, and surface acoustic wave resonator (SAWR) device behavior of AlN and ScxAl1-xN thin film piezoelectric materials. AlN has many properties that make it an ideal candidate for harsh environment SAW sensors, including the ability to remain piezoelectric up to 1200oC, stability in air up to 700oC, and relatively high phase velocity and low acoustic loss. In this work, piezoelectric AlN and ScxAl1-xN films were synthesized at 930oC using a nitrogen plasma-assisted e-beam evaporation growth method, and the influence of substrate preparation, Al flux, Sc flux, N-plasma flux, and the use of a TiN (111) seed layer were investigated. The films contain epitaxial (0002) oriented grains that yield piezoelectric coupling when integrated into SAWR devices, and the specific film growth parameters that determine epitaxial film quality are correlated with SAWR response and the film electromechanical coupling coefficient (k2). The piezoelectric strength of AlN can be enhanced by alloying with Sc to form a ScxAl1-xN film and this increases the magnitude of electromechanical coupling by up to 400%. ScxAl1-xN films were grown with Sc compositions ranging from 8% to 57% and the electromechanical coupling constant, k2, extracted from SAWR device measurements was found to be significantly increased compared to AlN. A prototype Sc0.13Al0.87N-based SAWR temperature sensor was fabricated and packaged at the Frontier Institute for Research in Sensor Technologies (FIRST) and tested on an exhaust baffle in the UMaine Steam Plant for over 1000 hours, demonstrating the transition of the research from a Technology Readiness Level of ‘experimental proof of concept’ to ‘system prototype demonstration in an operational environment’

    Integrated sensors for process monitoring and health monitoring in microsystems

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    This thesis presents the development of integrated sensors for health monitoring in Microsystems, which is an emerging method for early diagnostics of status or “health” of electronic systems and devices under operation based on embedded tests. Thin film meander temperature sensors have been designed with a minimum footprint of 240 m × 250 m. A microsensor array has been used successfully for accurate temperature monitoring of laser assisted polymer bonding for MEMS packaging. Using a frame-shaped beam, the temperature at centre of bottom substrate was obtained to be ~50 ºC lower than that obtained using a top-hat beam. This is highly beneficial for packaging of temperature sensitive MEMS devices. Polymer based surface acoustic wave humidity sensors were designed and successfully fabricated on 128° cut lithium niobate substrates. Based on reflection signals, a sensitivity of 0.26 dB/RH% was achieved between 8.6 %RH and 90.6 %RH. Fabricated piezoresistive pressure sensors have also been hybrid integrated and electrically contacted using a wire bonding method. Integrated sensors based on both LiNbO3 and ZnO/Si substrates are proposed. Integrated sensors were successfully fabricated on a LiNbO3 substrate with a footprint of 13 mm × 12 mm, having multi monitoring functions for simultaneous temperature, measurement of humidity and pressure in the health monitoring applications

    Smart Sensor Networks For Sensor-Neural Interface

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    One in every fifty Americans suffers from paralysis, and approximately 23% of paralysis cases are caused by spinal cord injury. To help the spinal cord injured gain functionality of their paralyzed or lost body parts, a sensor-neural-actuator system is commonly used. The system includes: 1) sensor nodes, 2) a central control unit, 3) the neural-computer interface and 4) actuators. This thesis focuses on a sensor-neural interface and presents the research related to circuits for the sensor-neural interface. In Chapter 2, three sensor designs are discussed, including a compressive sampling image sensor, an optical force sensor and a passive scattering force sensor. Chapter 3 discusses the design of the analog front-end circuit for the wireless sensor network system. A low-noise low-power analog front-end circuit in 0.5μm CMOS technology, a 12-bit 1MS/s successive approximation register (SAR) analog-to-digital converter (ADC) in 0.18μm CMOS process and a 6-bit asynchronous level-crossing ADC realized in 0.18μm CMOS process are presented. Chapter 4 shows the design of a low-power impulse-radio ultra-wide-band (IR-UWB) transceiver (TRx) that operates at a data rate of up to 10Mbps, with a power consumption of 4.9pJ/bit transmitted for the transmitter and 1.12nJ/bit received for the receiver. In Chapter 5, a wireless fully event-driven electrogoniometer is presented. The electrogoniometer is implemented using a pair of ultra-wide band (UWB) wireless smart sensor nodes interfacing with low power 3-axis accelerometers. The two smart sensor nodes are configured into a master node and a slave node, respectively. An experimental scenario data analysis shows higher than 90% reduction of the total data throughput using the proposed fully event-driven electrogoniometer to measure joint angle movements when compared with a synchronous Nyquist-rate sampling system. The main contribution of this thesis includes: 1) the sensor designs that emphasize power efficiency and data throughput efficiency; 2) the fully event-driven wireless sensor network system design that minimizes data throughput and optimizes power consumption

    Wireless Power Transfer Techniques for Implantable Medical Devices:A Review

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    Wireless power transfer (WPT) systems have become increasingly suitable solutions for the electrical powering of advanced multifunctional micro-electronic devices such as those found in current biomedical implants. The design and implementation of high power transfer efficiency WPT systems are, however, challenging. The size of the WPT system, the separation distance between the outside environment and location of the implanted medical device inside the body, the operating frequency and tissue safety due to power dissipation are key parameters to consider in the design of WPT systems. This article provides a systematic review of the wide range of WPT systems that have been investigated over the last two decades to improve overall system performance. The various strategies implemented to transfer wireless power in implantable medical devices (IMDs) were reviewed, which includes capacitive coupling, inductive coupling, magnetic resonance coupling and, more recently, acoustic and optical powering methods. The strengths and limitations of all these techniques are benchmarked against each other and particular emphasis is placed on comparing the implanted receiver size, the WPT distance, power transfer efficiency and tissue safety presented by the resulting systems. Necessary improvements and trends of each WPT techniques are also indicated per specific IMD
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