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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 667 records · Page 37

All sources NASA NTRS DOE OSTI

DOE OSTI2015

Optical seismic sensor systems and methods

Disclosed is an optical seismic sensor system for measuring seismic events in a geological formation, including a surface unit for generating and processing an optical signal, and a sensor device optically connected to the surface unit for receiving the optical signal over an optical conduit. The sensor device includes at least one sensor head for sensing a seismic disturbance from at least one direction during a deployment of the sensor device within a borehole of the geological formation. The sensor head includes a frame and a reference mass attached to the frame via at least one flexure, such that movement of the reference mass relative to the frame is constrained to a single predetermined path.

47 OTHER INSTRUMENTATION↗

DOE OSTI2013

Harsh Environment Silicon Carbide Sensor Technology for Geothermal Instrumentation

This project utilizes Silicon Carbide (SiC) materials platform to fabricate advanced sensors to be used as high-temperature downhole instrumentation for the DOE’s Geothermal Technologies Program on Enhanced Geothermal Systems. The scope of the proposed research is to 1) develop a SiC pressure sensor that can operate in harsh supercritical conditions, 2) develop a SiC temperature sensor that can operate in harsh supercritical conditions, 3) develop a bonding process for adhering SiC sensor die to well casing couplers, and 4) perform experimental exposure testing of sensor materials and the sensor devices.

47 OTHER INSTRUMENTATION↗

DOE OSTI2016

Sensors Umbra Package v 1.0

This package contains modules that model sensors in Umbra. There is a mix of modalities for both accumulating and tracking energy sensors: seismic, magnetic, and radiation. Some modules fuss information from multiple sensor types. Sensor devices (e.g., seismic sensors), detect objects such as people and vehicles that have sensor properties attached (e.g., seismic properties).

Oppel, Fred J.↗

DOE OSTI2018

Classification of Reactor Facility Operational State Using SPRT Methods with Radiation Sensor Networks

We consider the problem of inferring the operational state of a reactor facility by using measurements from a radiation sensor network, which is deployed around the facility’s ventilation stack. The radiation emissions from the stack decay with distance, and the corresponding measurements are inherently random with parameters determined by radiation intensity levels at the sensor locations. We fuse measurements from network sensors to estimate the intensity at the stack, and use this estimate in a one-sided Sequential Probability Ratio Test (SPRT) to infer the on/off state of the reactor facility. We demonstrate the superior performance of this method over conventional majority vote fusers and individual sensors using (i) test measurements from a network of NaI sensors, and (ii) emulated measurements using radioactive effluents collected at a reactor facility stack. We analytically quantify the performance improvements of individual sensors and their networks with adaptive thresholds over those with fixed ones, by using the packing number of the radiation intensity space.

Ramirez Aviles, Camila A.↗

DOE OSTI2018

Autonomous sensor fish to support advanced hydropower development

An improved sensor fish with robust design and enhanced measurement capabilities. This sensor fish contains sensors for acceleration, rotation, magnetic field intensity, pressure, and temperature. A low-power microcontroller collects data from the sensors and stores up to 5 minutes of data on a non-volatile flash memory. A rechargeable battery supplies power to the sensor fish. A recovery system helps locating sensor fish. The package, when ready for use is nearly neutrally buoyant and thus mimics the behavior of an actual fish.

Deng, Daniel Z.↗

DOE OSTI2019

High temperature sensor for reducing gas

The present disclosure provides improved sensor assemblies for gases. More particularly, the present disclosure provides for gas sensor assemblies operating at high temperature. Improved high temperature sensor assemblies for reducing gas are provided. In some embodiments, the present disclosure provides advantageous impedancemetric high temperature gas sensor assemblies based on electrospun nanofibers and having selectivity towards reducing gas, and related methods of use. In exemplary embodiments, the present disclosure provides for impedancemetric high temperature gas sensor assemblies having selectivity towards reducing gas. In certain embodiments, the sensor assembly includes electrospun nanofibers. Impedancemetric techniques have been employed at high operating frequency (e.g., 105 Hz) for the first time to provide real-time assemblies, methods and devices to sensitively and/or selectively detect reducing gas (e.g., CO, C3H8 (propane), etc.) at high temperatures (e.g., at about 800° C.).

Lei, Yu↗

DOE OSTI2019

Piezoresistive Characteristics of Silicon Carbide for Integrated Sensor Applications

Successful ubiquitous deployment of advanced reactors will depend to a large extent on the development of high-performance materials and sensors. Recently, there has been increasing interest in advanced reactors operating at very high temperatures (greater than 700 °C) and using molten salts as the primary coolant. In such reactor systems, temperature and pressure measurements are conducted using standard legacy thermocouples and pressure measurement technologies, both of which suffer from resolution issues, inaccuracies, and drift under harsh operating temperature and radiation conditions. We report on the structural, electrical, and mechanical characteristics of SiC materials and devices for the development of an integrated monolithic sensor unit capable of simultaneously monitoring temperature, pressure and flow in molten salt reactors, while at the same time exhibiting significant improvements in resolution, accuracy and signal-to-noise ratio.Wide bandgap and chemical inertness of SiC make it suitable for harsh environment sensor applications. We report on the development of a SiC pressure sensor exploiting its piezoresistive properties. Attempts have been made to fabricate thermally stable pressure sensor through doping induced high gauge factor. Both implanted and in-situ doped SiC wafers are being investigated to analyze the impact of dopant type and concentration on the piezoresistive characteristics. The microstructure, composition, and electrical conductivity of SiC samples have been analyzed to find optimum dopant incorporation and activation conditions. The mechanical measurements are being conducted on SiC beams with photolithographically defined surface piezoresistors to establish gauge factor for high performance sensors that can operate at temperatures beyond the limits of conventional silicon CMOS materials and devices.

Joshi, Pooran↗

DOE OSTI2020

Modular low cost trackerless spectral sensor

A photodiode sensor device and systems. The photodiode sensor device includes a housing portion. The housing portion includes a cylindrical enclosure. A window is disposed at a first end of the housing portion. A filter wheel is within the housing portion. A motor positioned within the housing is adjacent the filter wheel opposite the window. The motor is attached to the filter wheel. A photodiode sensor within the housing portion intermediate the first photodiode sensor and the window. The first photodiode sensor receives filtered light incident on the window and transmit a signal associated with sensed parameters of the filtered light. Also, a hemispherical dome for diffusing the light to a collimating lens has a grating, a focusing lens, and a linear detector array. An exit port transmits light to the collimating lens. The sensor array is opposite the grating for sensing the diffused light.

14 SOLAR ENERGY↗

DOE OSTI2021

Autonomous sensor fish to support advanced hydropower development

Deng, Z. Daniel↗

DOE OSTI2022

Efficient Implementation of Artificial Neural Networks for Sensor Data Analysis Based on a Genetic Algorithm

The reliability of many industrial processes depends on the sensor system. However, these sensors can be affected by noise, perturbations and failures. Hence, sensor monitoring and diagnosis are fundamental to guarantee the quality of an industrial process. Nowadays, artificial neural networks (ANN) are widely used in sensor signal processing and diagnosis. However, those ANNs usually require many artificial neurons, being difficult to implement in software and hardware due to their high computational costs. This paper presents an optimized implementation of artificial neurons in ANNs for sensor data analysis using a Genetic Algorithm (GA). The objective of GA is to find an adequate segmentation to reduce the activation function approximation error. One of the advantages of the proposed approach is that the cost function used in GA considers the effect of factors such as the ANN architecture or the number of bits used in arithmetic operations. The proposed ANN implementation technique aims to get the best possible approximation for a specific ANN architecture, making easier its implementation in software and hardware. Simulation and experimental results using FPGA (Field Programmable Gate Array) prove the advantages of the proposed approach for implementing sensor data analysis systems based on ANNs.

D estefani, André↗

DOE OSTI2019

PERFORMANCE CHARACTERISTICS OF A VECTOR SENSOR ARRAY IN AN ENERGETIC TIDAL CHANNEL

A compact three-dimensional vector sensor array (termed the NoiseSpotter) was recently developed with the goal of characterizing and localizing sources of sound in energetic environments such as those where marine renewable energy devices are likely to be located. The three vector sensors on the NoiseSpotter are mounted on a bottom platform with each sensor suspended inside an optional flow noise removal shield. The multiple pressure and particle velocity channels on the NoiseSpotter are simultaneously sampled and stored on-board to enable coherent array processing of vector sensor array data. A series of field trials were conducted where the NoiseSpotter was deployed on a bottom platform in an 8 m deep tidal channel in Sequim Bay, Washington. Pure tones were transmitted from a drifting vessel whose distance from the bottom platform varied between 50 m and 500 m. The effect of flow noise on vector sensor array performance is quantified along with the detectability of low intensity sound in an energetic environment. Flow noise removal efficiency for each channel of every vector sensor is demonstrated using multiple metrics derived from the active and reactive intensities computed using the pressure-velocity cross-spectral density matrix. A flow noise removal shield is shown to improve the detectability of low intensity sound such as those that are expected to be emitted by marine renewable energy devices.

Raghukumar, Kaustubha↗

DOE OSTI2023

Calibration technique of wall shear stress sensors using oscillating plate

Disclosed are a system and methods for calibrating wall shear stress sensors. The system includes an oscillating plate coupled to an actuator and mounted on a rolling elements, and one or more sensors coupled to a height adjusting device. The system can further comprise a height control rod coupled to a height control base and a sensor holder configured to house the one or more sensors and supported on a connector, the connector configured to be rotatably disposed about the height control rod. The system can be calibrated by causing the actuator to oscillate the oscillating plate at a frequency, sensing, using the one or more sensors, shear stress at a wall, the shear stress at the wall being associated with a velocity field, and determining a theoretical wall shear stress based on fluid properties, the frequency, and the height of the one or more sensors above the oscillating plate.

Freidkes, Brett R.↗

DOE OSTI2024

Optical Fiber Sensors Capable of Monitoring Hydrogen in the Subsurface Hydrogen Storage Environment

Subsurface hydrogen storage is a cost-effective and environmentally friendly storage option in a large quantity. Hydrogen would be stored in subsurface storage reservoirs at high temperature/pressure under very humid condition. Monitoring hydrogen concentration in those harsh storage environments is crucial to ensure the integrity and safety of the hydrogen storage infrastructure. Thus, this project focuses on the development of optical fiber hydrogen sensors capable of monitoring hydrogen in the harsh environments that are representative of underground storage conditions. The optical fiber hydrogen sensor developed at NETL consists of a palladium-based sensing film with a filter layer which minimizes the environmental impacts on hydrogen sensing. The developed sensor has demonstrated significant improvement on hydrogen sensing at 80℃ under high humidity condition (99% RH) without the baseline drift. The hydrogen sensor also showed negligible cross-sensitivity to CO2 and CH4 which would be present as a cushion gas inside the underground hydrogen storage reservoir. Moreover, the sensor has demonstrated the stable monitoring of hydrogen concentration at high pressure (1000 psi) and 80 ℃ in the presence of biological samples. The optical fiber hydrogen sensor developed would enable reliable monitoring of hydrogen concentration in subsurface hydrogen storage facilities.

Kim, Daejin↗

DOE OSTI2024

Embedding sensors in 3D-printed silicon carbide

An improved method for embedding one or more sensors in SiC is provided. The method includes depositing a binder onto successive layers of a SiC powder feedstock to produce a dimensionally stable green body have a true-sized cavity. A sensor component is then press-fit into the true-sized cavity. Alternatively, the green body is printed around the sensor component. The assembly (the green body and the sensor component) is heated within a chemical vapor infiltration (CVI) chamber for debinding, and a precursor gas is introduced for densifying the SiC matrix material. During infiltration, the sensor component becomes bonded to the densified SiC matrix, the sensor component being selected to be thermodynamically compatible with CVI byproducts at elevated temperatures, including temperatures in excess of 1000° C.

Petrie, Christian M.↗

DOE OSTI2024

Systems and methods for optical sensor protection

The present disclosure relates to an optical sensor protection system. The system may have a sensor for receiving an incoming optical signal, a passive sensing and modulation component, and an active sensing and modulation subsystem. The passive sensing and modulation component is configured to sense when a first characteristic is associated with the incoming optical signal is present that adversely affects operation of the sensor, and redirects at least a portion of the incoming optical signal thereof away from the sensor to thus reduce an intensity of the incoming optical signal reaching the sensor. The sensor is located on an image plane downstream of the ISM subsystem, relative to a path of travel of the incoming optical signal. The active sensing and modulation subsystem has an active modulation component and is located upstream of the passive sensing and modulation component, relative to the path of travel of the incoming optical signal, and is also located on a conjugate image plane, and is configured to use the redirected portion of the incoming optical signal as feedback in controlling a modification of the incoming optical signal to reduce a risk of damage to the passive sensing and modulation component.

Panas, Robert Matthew↗

DOE OSTI2022

Flexible CO 2 Sensor Architecture with Selective Nitrogen Functionalities by One‐Step Laser‐Induced Conversion of Versatile Organic Ink

Abstract Nitrogen‐containing carbons (NC) are a class of sustainable materials for selective CO 2 adsorption. A versatile concept is introduced to fabricate flexible NC‐based sensor architectures for room‐temperature sensing of CO 2 in a one‐step laser conversion of primary films cast from abundant precursors. By the unidirectional energy impact in conjunction with depth‐dependent attenuation of the laser beam, a layered sensor heterostructure with a porous transducer and active sensor layer is formed. Comprehensive microscopic and spectroscopic cross‐sectional analyses confirm the preservation of the high content of imidazolic nitrogen in the sensor. The performance is optimized in terms of material morphology, chemical composition, and surface chemistry to achieve a linear relative resistive response of up to Δ R / R 0 = −14.3% (10% of CO 2 ). Thermodynamic analysis yields Δ ads H values of −35.6 and 34.1 kJ·mol −1 for H 2 O and CO 2 , respectively. The sensor is operable even in humid environments (e.g., ∆ R / R 0,RH = 80% = 0.53%) and shows good performance upon strong mechanical deformation.

flexible gas sensors↗

DOE OSTI2022

Paper-based gold nanoparticles decorated SWCNTs chemiresistive sensor for sensitive detection of As(III) based on electrochemical doping

A paper-based chemiresistive sensor consisting of a single-walled carbon nanotubes network with electrodeposited gold nanoparticles (AuNPs-SWCNTs) was developed for the sensitive detection of As(III). A new sensing strategy was also proposed combined with a paper-based device for As(III) chemiresistive detection based on the electrochemical doping of As(0) on the AuNPs-SWCNTs channel. Here, the proposed paper-based chemiresistive sensor was manufactured by wax printing and vacuum deposition using a water-based SWCNTs ink. The sensor sensitivity was enhanced by optimizing the volume of SWCNTs ink used in the formation of the sensing network in the paper and the sweep segment of cyclic voltammetry used for the electrochemical deposition of AuNPs. Additionally, the mechanism of the sensing strategy based on the electrochemical n-doping of As(0) to the AuNPs-SWCNTs sensing channel was investigated using a liquid-ion gated FET system. The As(III) concentration detected by the as-fabricated chemiresistive sensor is as low as 1.35 × 10 -5 μM which is even lower than the maximum permissible concentration in drinking water defined by the WHO. In this paper, we provide a simple strategy for developing paper-based chemiresistive sensors with unique properties for practical As(III) determination.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2026

Near-field passive sensor for the monitoring of high-temperature oxidative corrosion of metals

This study reports on the development and testing of a passive wireless device designed to track temperature and corrosion behavior in SS304H stainless steel under elevated temperatures. The ANSYS HFSS software was utilized to model and optimize the design of an inductor-capacitor (LC) resonator passive wireless sensors fabricated using platinum designs printed onto an aluminum oxide support operating at frequencies between (50–190 MHz). The optimal LC wireless sensor designs were then fabricated using screen-printing and sintering methods. Here, the sensors were tested by placing the sensor onto polished SS304H flat substrates and heated to 900–1050 °C in air. Wireless acquisition of sensor data during heating, cooling, and isothermal stages was achieved through a Pt loop antenna connected to an RF signal generator and a network analyzer.

20 FOSSIL-FUELED POWER PLANTS↗