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At least 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Fe Thin Film-Coated Optics for Corrosion Monitoring: Optical and Electrochemical Studies

Corrosion proxy materials integrated with an optical sensing platform enable a real-time optical corrosion sensor for natural gas pipelines to prevent methane leaks and catastrophic events. Effects of CO 2 , pH, and film thickness on corrosion of Fe thin films (25, 50, 100 nm) were studied using optical and electrochemical methods in 3.5%wt. NaCl solutions at 30 °C. An increase in light transmission (T%) corresponded to corrosion of Fe thin films. CO 2 accelerated corrosion of Fe thin films due to the lower pH and the promoted corrosion reactions, resulting in a faster increase of T% than without CO 2 or at higher pH. While the corrosion rate increased with increasing film thickness, electrochemical corrosion of Fe thin films was in good agreement with that of bulk carbon steel, verifying that Fe thin films can serve as a representative corrosion proxy when integrated with the optical sensing platform.

36 MATERIALS SCIENCE↗
NASA NTRS2018

NASA Fluid Lensing & MiDAR - Next-Generation Remote Sensing Technologies for Aquatic Remote Sensing

Piti's Tepungan Bay and Tumon Bay, two of five marine preserves in Guam, have not been mapped to a level of detail sufficient to support proposed management strategies. This project addresses this gap by providing high resolution maps to promote sustainable, responsible use of the area while protecting natural resources. Dr. Chirayath, a research scientist at the NASA Ames Laboratory, developed a theoretical model and algorithm called 'Fluid Lensing'. Fluid lensing removes optical distortions caused by moving water, improving the clarity of the images taken of the corals below the surface. We will also be using MiDAR, a next-generation remote sensing instrument that provides real-time multispectral video using an array of LED emitters coupled with NASA's FluidCam Imaging System, which may assist Guam's coral reef response team in understanding the severity and magnitude of coral bleaching events. This project will produce a 3D orthorectified model of the shallow water coral reef ecosystems in Tumon Bay and Piti marine preserves. These 3D models may be printed, creating a tactile diorama and increasing understanding of coral reefs among various audiences, including key decision makers. More importantly, the final data products can enable accurate and quantitative health assessment capabilities for coral reef ecosystems.

Aquatic↗
NASA NTRS2007

An Experimental System for a Global Flood Prediction: From Satellite Precipitation Data to a Flood Inundation Map

Floods impact more people globally than any other type of natural disaster. It has been established by experience that the most effective means to reduce the property damage and life loss caused by floods is the development of flood early warning systems. However, advances for such a system have been constrained by the difficulty in estimating rainfall continuously over space (catchment-. national-, continental-. or even global-scale areas) and time (hourly to daily). Particularly, insufficient in situ data, long delay in data transmission and absence of real-time data sharing agreements in many trans-boundary basins hamper the development of a real-time system at the regional to global scale. In many countries around the world, particularly in the tropics where rainfall and flooding co-exist in abundance, satellite-based precipitation estimation may be the best source of rainfall data for those data scarce (ungauged) areas and trans-boundary basins. Satellite remote sensing data acquired and processed in real time can now provide the space-time information on rainfall fluxes needed to monitor severe flood events around the world. This can be achieved by integrating the satellite-derived forcing data with hydrological models, which can be parameterized by a tailored geospatial database. An example that is a key to this progress is NASA's contribution to the Tropical Rainfall Measuring Mission (TRMM), launched in November 1997. Hence, in an effort to evolve toward a more hydrologically-relevant flood alert system, this talk articulates a module-structured framework for quasi-global flood potential naming, that is 'up to date' with the state of the art on satellite rainfall estimation and the improved geospatial datasets. The system is modular in design with the flexibility that permits changes in the model structure and in the choice of components. Four major components included in the system are: 1) multi-satellite precipitation estimation; 2) characterization of land surface including digital elevation from NASA SRTM, topography-derived hydrologic parameters such as flood direction. flow accumulation, basin, and river network etc.; 3) spatially distributed hydrological models to infiltrate rainfall and route overland runoff; and 4) an implementation interface to relay thc input data to the models and display the flood inundation results to the users and decision-makers. Early results appear reasonable in terms of location and frequency of events. Case studies of this experimental system are evaluated with surface runoff data and other river monitoring systems. such as Dartmouth Flood Observatory's "Surface Water Watch" array of river reaches that are measured daily via other satellite remote sensing data. A major outcome of this progress will be the availability of a global overview of flood alerts that should consequently improve the performance of Decision Support System. We expect these developments in utilization of satellite remote sensing technology to offer a practical solution to the challenge of building a cost-effective early warning system for data scarce and under-developed areas.

Adler, Robert↗
NASA NTRS1983

Potential impact of remote sensing data on sea-state analysis and prediction

The severe North Atlantic storm which damaged the ocean liner Queen Elizabeth 2 (QE2) was studied to assess the impact of remotely sensed marine surface wind data obtained by SEASAT-A, on sea state specifications and forecasts. Alternate representations of the surface wind field in the QE2 storm were produced from the SEASAT enhanced data base, and from operational analyses based upon conventional data. The wind fields were used to drive a high resolution spectral ocean surface wave prediction model. Results show that sea state analyses would have been vastly improved during the period of storm formation and explosive development had remote sensing wind data been available in real time. A modest improvement in operational 12 to 24 hour wave forecasts would have followed automatically from the improved initial state specification made possible by the remote sensing data in both numerical and sea state prediction models. Significantly improved 24 to 48 hour wave forecasts require in addition to remote sensing data, refinement in the numerical and physical aspects of weather prediction models.

Cardone, V. J.↗
NASA NTRS1976

Investigation of Pearl River data collection system

The reliability of employing NASA developed remote sensing for in situ near real time monitoring of water quality in the Pearl River is evaluated. The placement, operation and maintenance of a number of NASA developed data collection platforms (DCP's) on the Pearl River are described. The reception, processing, and retransmission of water quality data from an ERTS satellite to the Mississippi Air and Water Pollution Control Commission (MAWPCC) via computer linkup are assessed.

Source record↗
NASA NTRS1992

Automatic Detection Of Faults In Turbomachinery Bearings

System of analog and digital signal-processing equipment, computers, and programs detects faults in ball bearings in turbomachines. System operates in real time, extracting information from vibrations sensed by accelerometers, strain gauges, and/or acoustical sensors. Vibrations caused when pits in balls contact races, and pits in races contact balls.

Higbie, Nathan B.↗
NASA NTRS1995

Evaluation testing of a portable vapor detector for Part-Per-Billion (PPB) level UDMH and N2H4

Trace level detection of hydrazine (N2H4), monomethyl hydrazine (MMH) and unsymmetrical dimethylhydrazine (UDMH) has been receiving increased attention over the past several years. In May 1995 the American Conference of Government Industrial Hygienists (ACGIH) lowered their acceptable threshold limit value (TLV) from 100 parts-per-billion (ppb) to 10 ppb. Several types of ppb-level detectors are being developed by the United States Air Force (USAF) Space and Missile Systems Center (SMSC). A breadboard version of a portable, lightweight hydrazine detection sensor was developed and produced by Giner Corp. for the USAF. This sensor was designed for ppb level UDMH and N2H4 vapor detection in near real-time. This instrument employs electrochemical sensing, utilizing a three electrode cell with an anion-exchange polymer electrolyte membrane as the only electrolyte in the system. The sensing, counter and reference electrodes are bonded to the membrane forming a single component. The only liquid required to maintain the sensor is deionized water which hydrates the membrane. At the request of the USAF SMSC, independent testing and evaluation of the breadboard instrument was performed at NASA's Toxic Vapor Detection Laboratory (TVDL) for response to ppb-level N2H4 and UDMH and MMH. The TVDL, located at Kennedy Space Center (KSC) has the unique ability to generate calibrated sample vapor streams of N2H4, UDMH, and MMH over a range from less than 10 ppb to thousands of parts per million (ppm) with full environmental control of relative humidity (0-90%) and temperature (0-50 C). The TVDL routinely performs these types of tests. Referenced sensors were subjected to extensive testing, including precision, linearity, response/recovery times, zero and span drift, humidity and temperature effects as well as ammonia interference. Results of these tests and general operation characteristics are reported.

Curran, Dan↗
NASA NTRS1996

Autonomous Synthesis of Goal-Oriented Behaviors for Planetary Robotic Sampling

An intelligent robotic architecture that autonomously synthesizes goal-oriented behaviors, while connecting sensing and action in real-time, is presented with applications to loosely defined planetary sampling missions. This architecture is composed of perception and action nets interconneted in closed loops.

perception↗
NASA NTRSDate not supplied

Strategies for Determining Safety of Fermented Foods Produced in Space

The BioNutrients experiments examine the feasibility of using microbially produced foods – yogurt, kefir, fermented food products– to supplement the current prepackaged food system to provide freshly synthesized nutrients and genetically engineered protein therapeutics to support crew health for sustainable and long duration crewed exploration. Safety of the products must be established as direct consumption of such products is a risk due to potential contamination with pathogenic organisms. Identifying pathogen contamination is particularly challenging as the fermenting cultures can mask the presence of contaminating organisms. Here we consider current methods of detecting coliforms, aerobic colonies, non-lactic acid bacteria, molds (yeasts), and specific pathogens including Staphylococcus aureus and salmonella. We also consider alternate and additional testing including sequencing and quantitative PCR. We investigate the use of the E-Nose developed by NASA Ames Research Center. This portable device senses volatile organic compounds in real time and can be trained to recognize “good” uncontaminated products from contaminated ones as a means of predicting food safety. Finally, we consider methods of in-flight pasteurization to increase safety and decrease overall microbial load of these products. This presentation will summarize testing status and outline the strategy that will be employed in the BioNutrients-3 ISS fermented foods experiment.

Natalie Ball↗
NASA NTRSDate not supplied

Strategies for Determining Safety of Fermented Foods Produced in Space

The BioNutrients experiments examine the feasibility of using microbially produced foods – yogurt, kefir, fermented food products– to supplement the current prepackaged food system to provide freshly synthesized nutrients and genetically engineered protein therapeutics to support crew health for sustainable and long duration crewed exploration. Safety of the products must be established as direct consumption of such products is a risk due to potential contamination with pathogenic organisms. Identifying pathogen contamination is particularly challenging as the fermenting cultures can mask the presence of contaminating organisms. Here we consider current methods of detecting coliforms, aerobic colonies, non-lactic acid bacteria, molds (yeasts), and specific pathogens including Staphylococcus aureus and salmonella. We also consider alternate and additional testing including sequencing and quantitative PCR. We investigate the use of the E-Nose developed by NASA Ames Research Center. This portable device senses volatile organic compounds in real time and can be trained to recognize “good” uncontaminated products from contaminated ones as a means of predicting food safety. Finally, we consider methods of in-flight pasteurization to increase safety and decrease overall microbial load of these products. This presentation will summarize testing status and outline the strategy that will be employed in the BioNutrients-3 ISS fermented foods experiment.

Food↗
NASA NTRS1989

Stand Alone Pressure Measurement Device (SAPMD) for the space shuttle Orbiter, part 1

The specifications for the Stand Alone Pressure Measurement Device (SAPMD) are as follows: the SAPMD shall measure ambient pressure at the surface of the Orbiter TPS in the range of 0 to 15 pounds per square inch absolute (PSIA). Measurement will begin at solid rocket booster (SRB) ignition as sensed by appropriate vibration sensing elements in the SAPMD. Pressure and corresponding real-time data are to be recorded every one tenth second for 140 seconds and at the end of the recording period, the operation will be discontinued with the data preserved for interrogation subsequent to Orbiter re-entry and landing. The type and size of the battery shall be such as to allow the vibration sensing elements and a real-time clock to be initialized a minimum of 30 day prior to launch and still provide power as necessary to perform the 140 second data recording period after SRB ignition. Battery installation shall be in such a manner as to allow battery replacement without removing the SAPMD from its position or removing more than one TPS tile. The SAPMD must be mounted in specific locations under tile of the TPS. To accommodate such mounting, the absolute maximum physical dimensions much not exceed 6.0 inches in length, 1.5 inches in width, and 0.4 inches in height, and the device shall be of such configuration that it can be bonded to the Orbiter skin at the joint line of two TPS tiles with the pressure sensing port at the surface of the tile. The SAPMD must remain operational in the temperature range of -40 to +85 C and survive storage temperature of -55 to +125 C. The pressure port must withstand 934 C without causing damage to the TPS during entry and must remain functional at 262 C during ascent. The accuracy of the pressure measurement must be plus or minus one-half PSIA over a temperature range of 0 to +36 C. All the specifications were met and verified by prototype testing and documented in the enclosed test data. Four flight-qualified models were fabricated and of these, two were delivered and successfully flown in the cargo bay of STS-26.

Tomlinson, Bill↗
NASA NTRS2001

A New Centimeter-Level Real-Time Global Navigation and Positioning Capability with GPS

NASA/JPL has developed a new, precise, global, GPS-based capability for real-time terrestrial and space platform navigation. It has been demonstrated on Earth's surface and is 10 times more accurate than other real-time GPS-based systems. The new system poses certain advantages for Earth science remote sensing, including: the onboard generation of science data products in real-time, sensor control and reduction of data transmission bandwidth, improved environmental forecasting, autonomous and intelligent platform control, operations cost savings, and technology transfer and commercial partnership opportunities. The system's measurement capabilities and applications, demonstrated orbit accuracies, and precision LEO and spacecraft positioning and timing are highlighted.

real time↗
DOE OSTI2020

One-Step Ahead Prediction of Thermal Mixing Tee Sensors with Long Short Term Memory (LSTM) Neural Networks

High-temperature advanced reactors under development, such as sodium fast reactors (SFR) and molten salt cooled reactors (MSCR), are expected to offer lower levelized cost of energy (LCOE) compared to existing light water reactor (LWR’s). In the existing light water reactors (LWR’s), operation and maintenance (O&M) expenses constitute the largest fraction of the total operating cost. Some of the O&M costs are related maintenance of sensors which can fail due to exposure to harsh environment in a reactor. The O&M costs of Advanced Reactor (AR)’s are expected to constitute a significant fraction of the total cost as well, because of high temperature and radiation level in AR are likely to cause material fatigue and premature failure of sensors and components. The O&M costs in AR’s could be reduced through integration of advanced informatics of performance-related sensors into a digital twin designed for reactor monitoring. For example, machine learning (ML) could be employed for real-time validation and correction of performance-related sensors, and reducing the number of performance-related physical sensor units through virtual sensing. As part of the effort, we investigate real-time validation of thermal hydraulic sensors through one-step ahead forecasting of sensor values using long short-term memory (LSTM) recurrent neural networks (RNN). The sensors are installed in a flow loop containing a thermal mixing tee, which is a common experimental model to study thermal fatigue in a thermal hydraulic loop. In addition, nonlinear transients generated in a thermal mixing tee constitute a good challenge data set for training and validation of ML algorithms. Sensors in this study include thermocouples, flow meters, and optical fibers for distributed temperature sensing. In one experiment, measurement data sets were obtained for a loop was filled with water, and in another experiment, measurements were performed on a loop filled with liquid metal Galinstan. We have also conducted preliminary investigation of one-step ahead prediction of fiber optics-based distributed temperature sensing with LSTM networks. In predicting fiber-based temperature measurements, we treated each gauge pitch of the fiber as an independent sensor. Accuracy of one-step ahead forecasting was estimated by calculating root mean square error (RMSE) for the test segment of time series of each sensor. RMSE’s for temperature sensors in water loop were, for the most part, lower than for the same sensors in Galinstan loop. The RMSE’s for flow meters were similar for both loops. The RMSE’s for distributed temperature measured with the fiber optic sensor were similar to those of the point sensors. Results of this study demonstrated the capability of LSTM one-step ahead forecasting with RMSE comparable to uncertainty in sensor measurements.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
NASA NTRS2008

Real-time In-Flight Strain and Deflection Monitoring with Fiber Optic Sensors

This viewgraph presentation reviews Dryden's efforts to develop in-flight monitoring based on Fiber Optics. One of the motivating factors for this development was the breakup of the Helios aircraft. On Ikhana the use of fiber optics for wing shape sensing is being developed. They are being used to flight validate fiber optic sensor measurements and real-time wing shape sensing predictions on NASA's Ikhana vehicle; validate fiber optic mathematical models and design tools; Assess technical viability and, if applicable, develop methodology and approach to incorporate wing shape measurements within the vehicle flight control system, and develop and flight validate advanced approaches to perform active wing shape control.

Richards, Lance↗
NASA NTRS1996

A Prototype WADGPS System for Real Time Sub-Meter Positioning Worldwide

Many planned and proposed NASA science activities will benefit from precise real time positioning with wide area differential GPS (WADGPS). Future NASA users include orbital remote sensing instruments (altimeters, SARs, imagers) and a variety of airborne and Earth based investigations. Real time positioning requirements and goals range from a few meters to a few centimeters. Direct benefits will include the enabling of missions that are not now possible (such as precision remote sensing from the space shuttle and space station) and dramatic reduction of analysis costs for a diversity of current investigations.

GPS↗
NASA NTRS2017

Multi-Objective Flight Control for Drag Minimization and Load Alleviation of High-Aspect Ratio Flexible Wing Aircraft

As aircraft wings become much more flexible due to the use of light-weight composites material, adverse aerodynamics at off-design performance can result from changes in wing shapes due to aeroelastic deflections. Increased drag, hence increased fuel burn, is a potential consequence. Without means for aeroelastic compensation, the benefit of weight reduction from the use of light-weight material could be offset by less optimal aerodynamic performance at off-design flight conditions. Performance Adaptive Aeroelastic Wing (PAAW) technology can potentially address these technical challenges for future flexible wing transports. PAAW technology leverages multi-disciplinary solutions to maximize the aerodynamic performance payoff of future adaptive wing design, while addressing simultaneously operational constraints that can prevent the optimal aerodynamic performance from being realized. These operational constraints include reduced flutter margins, increased airframe responses to gust and maneuver loads, pilot handling qualities, and ride qualities. All of these constraints while seeking the optimal aerodynamic performance present themselves as a multi-objective flight control problem. The paper presents a multi-objective flight control approach based on a drag-cognizant optimal control method. A concept of virtual control, which was previously introduced, is implemented to address the pair-wise flap motion constraints imposed by the elastomer material. This method is shown to be able to satisfy the constraints. Real-time drag minimization control is considered to be an important consideration for PAAW technology. Drag minimization control has many technical challenges such as sensing and control. An initial outline of a real-time drag minimization control has already been developed and will be further investigated in the future. A simulation study of a multi-objective flight control for a flight path angle command with aeroelastic mode suppression and drag minimization demonstrates the effectiveness of the proposed solution. In-flight structural loads are also an important consideration. As wing flexibility increases, maneuver load and gust load responses can be significant and therefore can pose safety and flight control concerns. In this paper, we will extend the multi-objective flight control framework to include load alleviation control. The study will focus initially on maneuver load minimization control, and then subsequently will address gust load alleviation control in future work.

Aerolasticity↗
NASA NTRS2006

"One-Stop Shopping" for Ocean Remote-Sensing and Model Data

OurOcean Portal 2.0 (http:// ourocean.jpl.nasa.gov) is a software system designed to enable users to easily gain access to ocean observation data, both remote-sensing and in-situ, configure and run an Ocean Model with observation data assimilated on a remote computer, and visualize both the observation data and the model outputs. At present, the observation data and models focus on the California coastal regions and Prince William Sound in Alaska. This system can be used to perform both real-time and retrospective analyses of remote-sensing data and model outputs. OurOcean Portal 2.0 incorporates state-of-the-art information technologies (IT) such as MySQL database, Java Web Server (Apache/Tomcat), Live Access Server (LAS), interactive graphics with Java Applet at the Client site and MatLab/GMT at the server site, and distributed computing. OurOcean currently serves over 20 real-time or historical ocean data products. The data are served in pre-generated plots or their native data format. For some of the datasets, users can choose different plotting parameters and produce customized graphics. OurOcean also serves 3D Ocean Model outputs generated by ROMS (Regional Ocean Model System) using LAS. The Live Access Server (LAS) software, developed by the Pacific Marine Environmental Laboratory (PMEL) of the National Oceanic and Atmospheric Administration (NOAA), is a configurable Web-server program designed to provide flexible access to geo-referenced scientific data. The model output can be views as plots in horizontal slices, depth profiles or time sequences, or can be downloaded as raw data in different data formats, such as NetCDF, ASCII, Binary, etc. The interactive visualization is provided by graphic software, Ferret, also developed by PMEL. In addition, OurOcean allows users with minimal computing resources to configure and run an Ocean Model with data assimilation on a remote computer. Users may select the forcing input, the data to be assimilated, the simulation period, and the output variables and submit the model to run on a backend parallel computer. When the run is complete, the output will be added to the LAS server for

Li, P. Peggy↗