Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Non-Contact sensing”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

46 records · Page 3
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Wireless Patch Antenna Characterization for Live Health Monitoring Using Machine Learning

Temperature monitoring in extreme environments, such as coal-fired power plants, was addressed by designing and testing wireless patch antennas for use in machine learning-aided temperature estimation. The sensors were designed to monitor the temperature and health of boiler systems. Wireless interrogation of the sensor was performed using a Vector Network Analyzer (VNA) and a pair of interrogation antennas to capture resonance behavior under varying thermal and spatial conditions with sensitivities ranging from 0.052 to 0.20 $\frac{𝑀𝐻𝑧}{°C}$. Sensor calibration was conducted using a Long Short-Term Memory (LSTM) model, which leveraged temporal patterns to account for hysteresis effects. The calibration method demonstrated improved performance when combined with an LSTM model, achieving up to a 76% improvement in temperature estimation error when compared with Linear Regression (LR). The experiments highlighted an innovative solution for patch antenna-based non-contact temperature measurement, which addresses limitations with conventional methods such as RFID-based systems, infrared, and thermocouples.

20 FOSSIL-FUELED POWER PLANTS↗
NASA NTRS2011

Lightweight Magnetic Cooler With a Reversible Circulator

A design of a highly efficient and lightweight space magnetic cooler has been developed that can continuously provide remote/distributed cooling at temperatures in the range of 2 K with a heat sink at about 15 K. The innovative design uses a cryogenic circulator that enables the cooler to operate at a high cycle frequency to achieve a large cooling capacity. The ability to provide remote/distributed cooling not only allows flexible integration with a payload and spacecraft, but also reduces the mass of the magnetic shields needed. The active magnetic regenerative refrigerator (AMRR) system is shown in the figure. This design mainly consists of two identical magnetic regenerators surrounded by their superconducting magnets and a reversible circulator. Each regenerator also has a heat exchanger at its warm end to reject the magnetization heat to the heat sink, and the two regenerators share a cold-end heat exchanger to absorb heat from a cooling target. The circulator controls the flow direction, which cycles in concert with the magnetic fields, to facilitate heat transfer. Helium enters the hot end of the demagnetized column, is cooled by the refrigerant, and passes into the cold-end heat exchanger to absorb heat. The helium then enters the cold end of the magnetized column, absorbing heat from the refrigerant, and enters the hot-end heat exchanger to reject the magnetization heat. The efficient heat transfer in the AMRR allows the system to operate at a relatively short cycle period to achieve a large cooling power. The key mechanical components in the magnetic cooler are the reversible circulator and the magnetic regenerators. The circulator uses non-contacting, self-acting gas bearings and clearance seals to achieve long life and vibration- free operation. There are no valves or mechanical wear in this circulator, so the reliability is predicted to be very high. The magnetic regenerator employs a structured bed configuration. The core consists of a stack of thin GGG disks alternating with thin polymer insulating films. The structured bed reduces flow resistance in the regenerator and therefore the pumping work by the cryogenic circulator. This magnetic cooler will enable cryogenic detectors for sensing infrared, x-ray, gamma-ray, and submillimeter radiation in future science satellites, as well as the detector systems in the Constellation-X (Con-X) and the Single Aperture Far-Infrared observatory (SAFIR). Scientific ap p - lica tions for this innovation include cooling for x-ray micro calorimeter spectrometers used for microanalysis, cryogenic particle detectors, and superconducting tunnel junction de tectors for biomolecule mass spectrometry. The cooler can be scaled to provide very large cooling capacities at very low temperatures, ideal for liquid helium and liquid hydrogen productions.

Chen, Weibo↗
NASA NTRSDate not supplied

Laser Forming of Sheet Metal for In-Space Manufacturing Applications

As the in-space economy matures, the migration of typically Earth-bound manufacturing methods, such as metal forming and joining, up to space will be required to meet the increasing demand for refueling and supply depots, habitats, laboratories, lunar surface structures, and sites for deep-space exploration shipbuilding. Only in this way can the magnitude of individual structures begin to exceed what can be launched, deployed, docked, or inflated and allow true economies of scale to be unlocked in space. However, typical terrestrial methods of forming and shaping sheet metal require massive machinery with the ability to deflect reaction forces to a large mass in a fixed reference frame (Earth). To both limit up-mass required for manufacture and to mitigate the issues of reaction forces in the relative reference frames of space, a non-contact, laser-based method of forming metal sheet is proposed. NASA Marshall Space Flight Center (MSFC), in cooperation with DARPA and the University of Florida (UF), have begun investigation of non-contact methods of laser forming sheet metal in thermal vacuum (TVAC) conditions to great success. To date, several grades of aluminum, stainless steel, and titanium coupons have been formed via laser-induced internal stresses in these metals at both ambient atmosphere and vacuum conditions. Temperatures in these tests ranged from -120 to 60 C, and though the total energy required to induce strain does vary with workpiece temperature and environmental pressure, the method remains predictable and controllable for the materials investigated. It is believed that this method will revolutionize manufacturing in-space as it not only continues to build upon the capabilities of the laser (sensing, marking, cutting, drilling, joining, and now forming) as an all-in-one tool, but also reduces the need to counteract forming forces as would be required in mechanical bending. In theory, all required stress to induce bending is generated through thermal gradient and strain within the workpiece, meaning that the need for reaction control and fuel expense on-orbit will be limited. Archimedes once stated, “Give me a lever long enough and a fulcrum on which to place it, and I shall move the world”. With a laser as our lever and our workpiece its own fulcrum, we can move the world’s manufacturing into space.

Laser↗
NASA NTRS1989

Report on the multicolor pyrometry session at the Second NASA Non-Contact Temperature-Measurement Workshop

The session met jointly with the other special sessions. Due to time constraints, the concerns of multicolor pyrometry were not addressed in depth. Multicolor pyrometry attempts to determine an object's temperature and emittance as a function of wavelength from simultaneous measurement of the spectral radiance of the object at multiple wavelengths. The main issues are those of the most appropriate model for the wavelength dependence of the emittance, the number of undetermined parameters, and the error in the measured temperature. It has long been known that it is inappropriate to attempt to model the emittance with a functional form that contains as many unknowns as wavelengths. Such attempts will lead to gross errors in the measured temperature. However, more recent work by Hunter and Khan has indicated that emittance can be modeled by a function with many fewer degrees of freedom than sampled wavelengths (e.g., it may be appropriate to use a second order polynomial to fit data from a forty-color pyrometer). In a platform lecture, Khan described algorithms for determination of the parameters by minimization of the errors between the model and the data in a least-squares sense. The first was a linear method and the second was a non-linear method where the emittance could assume any functional form. Both methods were shown to be very sensitive to random noise and non-linearity in the measurement system.

Spjut, R. Erik↗
NASA NTRS2011

NASA Tech Briefs, February 2011

Topics covered include: Multi-Segment Radius Measurement Using an Absolute Distance Meter Through a Null Assembly; Fiber-Optic Magnetic-Field-Strength Measurement System for Lightning Detection; Photocatalytic Active Radiation Measurements and Use; Computer Generated Hologram System for Wavefront Measurement System Calibration; Non-Contact Thermal Properties Measurement with Low-Power Laser and IR Camera System; SpaceCube 2.0: An Advanced Hybrid Onboard Data Processor; CMOS Imager Has Better Cross-Talk and Full-Well Performance; High-Performance Wireless Telemetry; Telemetry-Based Ranging; JWST Wavefront Control Toolbox; Java Image I/O for VICAR, PDS, and ISIS; X-Band Acquisition Aid Software; Antimicrobial-Coated Granules for Disinfecting Water; Range 7 Scanner Integration with PaR Robot Scanning System; Methods of Antimicrobial Coating of Diverse Materials; High-Operating-Temperature Barrier Infrared Detector with Tailorable Cutoff Wavelength; A Model of Reduced Kinetics for Alkane Oxidation Using Constituents and Species for N-Heptane; Thermally Conductive Tape Based on Carbon Nanotube Arrays; Two Catalysts for Selective Oxidation of Contaminant Gases; Nanoscale Metal Oxide Semiconductors for Gas Sensing; Lightweight, Ultra-High-Temperature, CMC-Lined Carbon/Carbon Structures; Sample Acquisition and Handling System from a Remote Platform; Improved Rare-Earth Emitter Hollow Cathode; High-Temperature Smart Structures for Engine Noise Reduction and Performance Enhancement; Cryogenic Scan Mechanism for Fourier Transform Spectrometer; Piezoelectric Rotary Tube Motor; Thermoelectric Energy Conversion Technology for High-Altitude Airships; Combustor Computations for CO2-Neutral Aviation; Use of Dynamic Distortion to Predict and Alleviate Loss of Control; Cycle Time Reduction in Trapped Mercury Ion Atomic Frequency Standards; and A (201)Hg+ Comagnetometer for (199)Hg+ Trapped Ion Space Atomic Clocks.

Source record↗
NASA NTRS2011

High-Temperature Thermometer Using Cr-Doped GdAlO3 Broadband Luminescence

A new concept has been developed for a high-temperature luminescence-based optical thermometer that both shows the desired temperature sensitivity in the upper temperature range of present state-of-the-art luminescence thermometers (above 1,300 C), while maintaining substantial stronger luminescence signal intensity that will allow these optical thermometers to operate in the presence of the high thermal background radiation typical of industrial applications. This objective is attained by using a Cr-doped GdAlO3 (Cr:GdAlO3) sensor with an orthorhombic perovskite structure, resulting in broadband luminescence that remains strong at high temperature due to the favorable electron energy level spacing of Cr:GdAlO3. The Cr:GdAlO3 temperature (and pressure) sensor can be incorporated into, or applied onto, a component s surface when a non-contact surface temperature measurement is desired, or alternatively, the temperature sensor can be attached to the end of a fiber-optic probe that can then be positioned at the location where the temperature measurement is desired. In the case of the fiber-optic probe, both the pulsed excitation and the luminescence emission travel through the fiber-optic light guide. In either case, a pulsed light source provides excitation of the luminescence, and the broadband luminescence emission is collected. Real-time temperature measurements are obtain ed using a least-squares fitting algorithm that determines the luminescence decay time, which has a known temperature dependence established by calibration. Due to the broad absorption and emission bands for Cr:GdAlO3, there is considerable flexibility in the choice of excitation wavelength and emission wavelength detection bands. The strategic choice of the GdAlO3 host is based on its high crystal field, phase stability, and distorted symmetry at the Cr3+ occupation sites. The use of the broadband emission for temperature sensing at high temperatures is a key feature of the invention and is novel since broadband luminescence emission normally shows severe thermal quenching. The tightly bound AlO6 octahedra in GdAlO3 results in a larger energy barrier to nonradiative decays than in other materials and therefore makes using broadband emission for temperature sensing possible at high temperatures. This approach results in a substantial increase in temperature capability. For example, the most commonly used Cr-doped crystal used for luminescence-based temperature measurements, ruby, has only been demonstrated up to 600 C, whereas the Cr:GdAlO3 optical thermometer under development has already been shown to exhibit useful luminescence up to 1,300 C. Because GdAlO3 is non-reactive and is stable in harsh, high-temperature environments, sensors composed of Cr:GdAlO3 will be very well suited for remote high-temperature measurements in engine or industrial environments where its intense high-temperature luminescence will stand out above significant thermal radiation background levels.

Eldridge, Jeffrey↗
DOE OSTI2021

On-chip optical tweezers based on freeform optics

Since its advent in the 1970s, optical tweezers have been widely deployed as a preferred non-contact technique for manipulating microscale objects. On-chip integrated optical tweezers, which afford significant size, weight, and cost benefits, have been implemented, relying upon near-field evanescent waves. As a result, these tweezers are only capable of manipulation in near-surface regions and often demand high power since the evanescent interactions are relatively weak. We introduce on-chip optical tweezers based on freeform micro-optics, which comprise optical reflectors or refractive lenses integrated on waveguide end facets via two-photon polymerization. The freeform optical design offers unprecedented degrees of freedom to design optical fields with strong three-dimensional intensity gradients, useful for trapping and manipulating suspended particles in an integrated chip-scale platform. We demonstrate the design, fabrication, and measurement of both reflective and refractive micro-optical tweezers. The reflective tweezers feature a remarkably low trapping threshold power, and the refractive tweezers are particularly useful for multiparticle trapping and interparticle interaction analysis. Our integrated micro-optical tweezers uniquely combine a compact footprint, broadband operation, high trapping efficiency, and scalable integration with planar photonic circuits. This class of tweezers is promising for on-chip sensing, cell assembly, particle dynamics analysis, and ion trapping.

Yu, Shaoliang (ORCID:000000026072425X)↗
DOE OSTI2025

Detection limits for laser absorption spectroscopy of Li in laser ablation plumes

A high-sensitivity laser absorption spectroscopy (LAS) method is demonstrated for rapid and non-contact analysis of Li in solids. Glass samples with Li concentrations ranging from 1-500 ppm by mass are ablated in 5 Torr air, and time-resolved Li atomic absorption is measured using a tunable laser near 671 nm. Significant improvements in analytical performance over prior laser-induced breakdown techniques are demonstrated. Here, a single-shot limit of detection (LOD) of 180 ppb is shown for fixed wavelength operation, improving to 6 ppb with averaging over 1000 ablation shots (100 s acquisition time). Isotope-resolved Li absorption spectra are measured with a 17 ppb LOD in 40 s. Methods for optimizing LOD based on noise/averaging properties of LAS experiments in LA plumes are discussed.

(020.3260) Isotope shifts↗
DOE OSTI2020

Non-invasive (non-contact) measurements of human thermal physiology signals and thermal comfort/discomfort poses -A review

Heating, ventilation and air-conditioning (HVAC) systems have been adopted to create comfortable, healthy and safe indoor environments. In the control loop, the technical feature of the human demand-oriented supply can help operate HVAC effectively. Among many technical options, real time monitoring based on feedback signals from end users has been frequently reported as a critical technology to confirm optimizing building performance. Recent studies have incorporated human thermal physiology signals and thermal comfort/discomfort status as real-time feedback signals. A series of human subject experiments used to be conducted by primarily adopting subjective questionnaire surveys in a lab-setting study, which is limited in the application for reality. With the help of advanced technologies, physiological signals have been detected, measured and processed by using multiple technical formats, such as wearable sensors. Nevertheless, they mostly require physical contacts with the skin surface in spite of the small physical dimension and compatibility with other wearable accessories, such as goggles, and intelligent bracelets. Most recently, a low cost small infrared camera has been adopted for monitoring human facial images, which could detect the facial skin temperature and blood perfusion in a contactless way. Also, according to latest pilot studies, a conventional digital camera can generate infrared images with the help of new methods, such as the Euler video magnification technology. Human thermal comfort/discomfort poses can also be detected by video methods without contacting human bodies and be analyzed by the skeleton keypoints model. Here, new sensing technologies were summarized, their cons and pros were discussed, and extended applications for the demand-oriented ventilation were also reviewed as potential development and applications.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
NASA NTRS1992

Elastic and plastic strain measurement in high temperature environment using laser speckle

Two laser speckle methods are described to measure strain in high temperature environment and thermal strain caused by high temperature. Both are non-contact, non-destructive and remote sensing techniques that can be automated. The methods have different but overlapping ranges of application with one being more suitable for large plastic deformation.

Chiang, Fu-Pen↗