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At least 1,711 records · Page 95

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DOE OSTI2019

Continuous Water Quality Sensing for FGD Wastewater

The coal fired plant power industry requires new solutions for on-line monitoring of flue gas desulfurization (FGD) wastewaters for regulated trace metals to reduce recurring operating and off-site laboratory analysis costs and provide a high level of confidence of compliance with state and federal discharge guidelines. The University of Alabama at Birmingham (UAB) developed an integrated water sensor package for continuous water quality monitoring of flue gas desulfurization (FGD) wastewaters for concentration measurements of Selenium (Se). UAB utilized a diverse team of University Professors/Staff Members/Student(s) (Engineering and Innovative Technology Development Group), a University Affiliated Research Institution from the local area (Southern Research), and a cost sharing Industry Partner (Metrohm). The team developed and validated a proprietary wet chemistry batch process for water sample preparation; and implemented this process as a fully automated on-line monitor prototype system. This prototype system’s performance was evaluated in both the laboratory and during in-field deployment to a coal fired power plant. In both environments it was found that the prototype system was unable to recreate the batch process’s success at preparing FGD water samples for total Se measurements with a commercial-off-the-shelf (COTS) cyclic anodic stripping voltammetry (CSV) system. Through this experience, UAB has provided insight into a number of specific areas where improvements can be made with respect to the COTS systems used in this project to yield a more complete and competitive industry solution for on-line monitoring of total Se in industrial wastewater.

20 FOSSIL-FUELED POWER PLANTS↗

DOE OSTI2020

Continuous Water Quality Sensing for FGD Wastewater

01 COAL, LIGNITE, AND PEAT↗

DOE OSTI2022

Data Compression in the NEXT-100 Data Acquisition System

NEXT collaboration detectors are based on energy measured by an array of photomultipliers (PMT) and topological event filtering based on an array of silicon photomultipliers (SiPMs). The readout of the PMT sensors for low-frequency noise effects and detector safety issues requires a grounded cathode connection that makes the readout AC-couple with variations in the signal baseline. Strict detector requirements of energy resolution better than 1% FWHM require a precise baseline reconstruction that is performed offline for data analysis and detector performance characterization. Baseline variations make it inefficient to apply traditional lossy data compression techniques, such as zero-suppression, that help to minimize data throughput and, therefore, the dead time of the system. However, for the readout of the SiPM sensors with less demanding requirements in terms of accuracy, a traditional zero-suppression is currently applied with a configuration that allows for a compression ratio of around 71%. The third stage in the NEXT detectors program, the NEXT-100 detector, is a 100 kg detector that instruments approximately five times more PMT sensors and twice the number of SiPM sensors than its predecessor, the NEXT-White detector, putting more pressure in the DAQ throughput, expected to be over 900 MB/s with the current configuration, which will worsen the dead time of the acquisition data system. This paper describes the data compression techniques applied to the sensor data in the NEXT-100 detector, which reduces data throughput and minimizes dead time while maintaining the event rate to the level of its predecessor, around 50 Hz.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2017

Modeling Control Strategies and Range Impacts for Electric Vehicle Integrated Thermal Management Systems with MATLAB/Simulink

The National Renewable Energy Laboratory's (NREL's) CoolSim MATLAB/Simulink modeling framework was used to explore control strategies for an electric vehicle combined loop system. Three system variants of increased complexity and efficiency were explored: a glycol-based positive temperature coefficient heater (PTC), PTC with power electronics and electric motor (PEEM) waste heat recovery, and PTC with PEEM waste heat recovery plus heat pump versions. Additionally, the benefit of electric motor preheating was considered. A two-level control strategy was developed where the mode selection and component control were treated separately. Only the parameters typically available by vehicle sensors were used to control the system. The control approach included a mode selection algorithm and controllers for the compressor speed, cabin blower flow rate, coolant flow rate, and the front-end heat exchanger coolant bypass rate. The electric motor was bypassed by the cooling circuit until its temperature exceeded the coolant inlet temperature. The impact of these thermal systems on electric vehicle range during warmup was simulated for the Urban Dynamometer Driving Schedule (UDDS) and Highway Fuel Economy Test (HWFET2X) drive cycles weighted 45%/55% respectively. A range of ambient temperatures from -20 degrees C to +20 degrees C was considered. NREL's Future Automotive Systems Technology Simulator (FASTSim) vehicle modeling tool showed up to a 10.9% improvement in range for the full system over the baseline during warmup from cold soak. The full system with preheat showed up to 17% improvement in range.

33 ADVANCED PROPULSION SYSTEMS↗

NASA NTRS1973

Remote control of planetary surface vehicles.

A remotely manned system consisting of an earth-based control center and a remote rover system on the planetary surface is assumed to extend to the remote site the sensory, manipulative and certain intellectual capabilities of humans here on earth. Required system functions, including scientific payload functions, vehicle functions and ground-based human control functions are discussed and the effects of communication delay and increased remote automaticity on system performance are investigated. To accomplish the required operations for scientific exploration, the control of the remote system requires the development of techniques to deal with problems of long communication time delays so that the performance in terms of operation speed can be increased to acceptable levels. Increased operational performance can be achieved primarily by increasing the rate of useful information flow in the man-machine sensor-control loop, or by increasing the autonomous capabilities of the remote system or by both.

Heer, E.↗

NASA NTRS1976

Remote measurement of water color

This paper contains a discussion of the requirements and approaches which can be taken in the development of techniques for the analysis of remote multispectral imagery of natural bodies of water. There are two general approaches which can be used in the analysis of multispectral water color data collected by aircraft or satellite remote sensors. With the theoretical modeling approach, optically important constituents of natural waters are mathematically related to the upwelling radiance spectrum received by the remote sensor. With the empirical approach, the relationships are determined empirically by comparing remote sensing data with surface truth data. There are several levels of mathematical sophistication which can be applied to both approaches. The two approaches are discussed in some detail and it is concluded that the two approaches are closely related and should be pursued simultaneously for maximum utilization of the laboratory and field measurement data which will be needed. A set of minimum surface truth measurement parameters and techniques is suggested.

Mccluney, W. R.↗

NASA NTRS1980

Coal thickness guage using RRAS techniques, parts 2 and 3

Electron magnetic resonance was investigated as a sensing technique for use in measuring the thickness of the layer of coal overlying the rock substrate. The goal is development of a thickness gauge which will be usable for control of mining machinery to maintain the coal thickness within selected bounds. A sensor must be noncontracting, have a measurement range of 6 inches or more, and an accuracy of 1/2 inch or better. The sensor should be insensitive to variations in spacing between the sensor and the surface, the response speed should be adequate to permit use on continuous mining equipment, and the device should be rugged and otherwise suited for operation under conditions of high vibration, moisture, and dust. Finally, the sensor measurement must not be adversely affected by the natural effects occurring in coal such as impurities, voids, cracks, layering, high moisture level, and other conditions that are likely to be encountered.

King, J. D.↗

NASA NTRS1983

In-progress absolute radiometric inflight calibration of the LANDSAT-4 sensors

An approach is described for providing periodic inflight absolute radiometric calibrations of the LANDSAT-4 sensors by reference to selected, instrumented ground areas. Results of some early ground measurements and computer simulations are presented. Selection of a suitable ground reference site, accurate measurement of the spectral reflectance of the selected area, determination of atmospheric characteristics during the morning of the sensor overpass, reduction of the measured data and their use in an appropriate atmospheric radiative transfer program, and comparison of the radiance level data with the digital counts of for the images of the selected areas are discussed. Preliminary measurements of gypsum are being made as an aid in defining the characteristics of field equipment to be constructed and calibrated for use over the White Sands Missile Range.

Castle, K.↗

NASA NTRS1984

Radiometric analyses of Landsat-4 digital image data

The results of analyses of the radiometric characteristics of digital image data produced by the Landsat 4 MSS and TM sensors are reviewed. The MSS analysis found high quality data comparable to the products of previous Landsats, except for a low-level coherent noise effect having a magnitude of about 0.5 counts in each band and a spatial period of about 3.6 pixels. The TM analysis found excellent spatial resolution, generally high data quality and expected scan-angle effects. Procedures for equalizing detector responses appear to be working as intended. Two low-amplitude artifacts also were discovered. The first is associated with the direction of scan (TM employs bidirectional scanning). The second, a very low employs bidirectional scanning). The second, a very low frequency level-shift artifact which produces image banding that is most pronounced in TM1, could be a serious problem for water-related applications or others where average signal levels are low. Correction procedures are under investigation.

Malila, W. A.↗

NASA NTRS1984

Development of robots and application to industrial processes

An algorithm is presented for using a robot system with a single camera to position in three-dimensional space a slender object for insertion into a hole; for example, an electrical pin-type termination into a connector hole. The algorithm relies on a control-configured end effector to achieve the required horizontal translations and rotational motion, and it does not require camera calibration. A force sensor in each fingertip is integrated with the vision system to allow the robot to teach itself new reference points when different connectors and pins are used. Variability in the grasped orientation and position of the pin can be accomodated with the sensor system. Performance tests show that the system is feasible. More work is needed to determine more precisely the effects of lighting levels and lighting direction.

Palm, W. J.↗

NASA NTRS1985

Effect of Landsat Thematic Mapper sensor parameters on land cover classification

Selected sensor parameter differences between TM and MSS were assessed through classification performance of a suburban/regional test site. Overall classification accuracy of a seven-band Landsat TM scene in comparison to MSS yielded an improvement in accuracy from 74.8 percent to 83.2 percent. To study the possible causes for the difference in classification performance, key sensor parameter differences between MSS and TM, including: (1) spatial resolution (30 m for TM versus 80 m for MSS), (2) quantization level (256 levels for TM versus 64 for MSS), and (3) spectral regions (seven bands in four major spectral regions for TM versus four bands in two regions for MSS), were evaluated. Landsat TM data were processed to stimulate all possible combinations of these MSS and TM parameters, yielding a three-factor design with two levels per factor. The results indicated that the added spectral regions (TM 1, TM 5, and TM 7) and to a lesser degree the increase in quantization level to eight bits produced the improved TM classification accuracy. However, in this study, the higher 30 m spatial resolution of TM contributed to a reduced classification accuracy from increased within-field variability or class heterogeneity.

Toll, D. L.↗

NASA NTRS1986

Analysis of interference to remote passive microwave sensors

The final acts of the 1979 World Administrative Radio Conference (WARC) were analyzed to determine potential interference to remote passive microwave sensors. Using interferer populations determined from the U.S. Government and FCC Master File Lists and assuming uniform geographical distribution of interferers, the level of interference from shared services and active services in adjacent and subharmonic bands was calculated for each of the 22 passive sensing bands. In addition, due to the theoretically large antennas required for passive sensing, an analysis was performed to determine if smaller antennas, i.e., relaxed resolution requirements, would have an effect on interference and to what extent.

Boyd, Douglas↗

NASA NTRS1992

Postflight aerothermodynamic analysis of Pegasus(tm) using computational fluid dynamic techniques

The objective was to validate the computational capability of the NASA Ames Navier-Stokes code, F3D, for flows at high Mach numbers using comparison flight test data from the Pegasus (tm) air launched, winged space booster. Comparisons were made with temperature and heat fluxes estimated from measurements on the wing surfaces and wing-fuselage fairings. Tests were conducted for solution convergence, sensitivity to grid density, and effects of distributing grid points to provide high density near temperature and heat flux sensors. The measured temperatures were from sensors embedded in the ablating thermal protection system. Surface heat fluxes were from plugs fabricated of highly insulative, nonablating material, and mounted level with the surface of the surrounding ablative material. As a preflight design tool, the F3D code produces accurate predictions of heat transfer and other aerodynamic properties, and it can provide detailed data for assessment of boundary layer separation, shock waves, and vortex formation. As a postflight analysis tool, the code provides a way to clarify and interpret the measured results.

Kuhn, Gary D.↗

NASA NTRS1990

Jet Propulsion Laboratory/Kennedy Space Center telerobotic inspection and manipulation demonstration

The goal of this effort is to demonstrate telerobotic inspection and mainpulation of space shuttle payloads in the presence of substantial communications time delays between the operator station and the robotic work space. The processing of space shuttle payloads provides a variety of tasks which are typical of both space shuttle ground operations and Space Station in-flight operations, and communications time delays are inevitable in space operations where the operator station will be light-seconds away from the telerobot. With this demonstration we hope to show the efficacy and safety of robotic technology for ground and space operations. Our approach is to develop an experimental telerobotic system with the remote sensing, actuation and reflex portions located at KSC in Florida, while the operator control station will be located at Jet Propulsion Laboratory (JPL) in California. The JPL portion of the system includes a high-level operator interface, intelligent spatial planning and machine vision, while the KSC portion includes the robot arm, end effectors, cameras and proximity sensors, and the necessary control and communications computers and software. The communications between JPL and KSC are over a limited-bandwidth network channel (19200 baud) with unpredictable and unrepeatable time delays. In FY89 we integrated a basic version of the robotic, communications, and computer hardware, and we developed the software to perform an operator-supervised inspection of a PAM-D satellite upper stage rocket motor and its shuttle support cradle. The demonstration, though severely limited by the bulk of the available computer arm, showed the potential of telerobotics for inspection tasks. In the future, we plan to develop additional capabilities which will allow manipulation tasks to be performed, including removal of dust covers and lens caps, insertion of connectors and batteries, and installation of payload objects.

Wilcox, Brian↗

NASA NTRS1993

Advanced microfabrication technologies for microspacecraft

Advanced microfabrication technologies offer the prospect of reducing the weight and size of spacecraft through the use of lighter and stronger materials in conjunction with new mechanical/structural design concepts and design optimization methods. At the same time, electronic components have been scaled down while increasing functional utility. A two-fold benefit is derived for space applications through the use of less expensive components and the lower launch costs associated with lighter components. GE-CRD is actively pursuing research in these key technologies for a wide range of applications including satellites. These key technologies will be reviewed and an update on GE progress will be given. The need to reduce weight and lower cost, while maintaining product quality and reliability are primary drivers in the design of satellites, in general, and microsatellites in particular. For the structural subsystem, these requirements pose a complex design problem unless new mechanical design concepts and computer-aided design optimization methods are employed. Several new concepts, such as battery packs doubling as panel reinforcements and fuel tanks as integral structural members, need to utilized. In addition, new viscoelastic material damping concepts for spacecraft components provide for lighter weight/lower cost designs, while satisfying the structural dynamics requirements. High density interconnect (HDI) technology permits the use of bare IC's on a ceramic substrate with 90 percent active area utilization. A copper/polyimide multilayer structure is the backbone of the technology, which has demonstrated a size/weight reduction of greater than 10x compared to printed circuit board with performance up to the GHz level. HDI modules have exceptional mechanical robustness as evidenced by survival of 180 kg rapid acceleration tests. Microelectromechanical systems (MEMS) are redefining sensors and actuators by miniaturization through micromachining techniques. Sharing many fabrication steps with HDI, we have developed a new technique for surface micromachining of copper/polyimide structures using computer-aided laser patterning.

Ghezzo, M.↗

NASA NTRS1998

Midcourse Space Experiment Data Certification and Technology Transfer

The Midcourse Space Experiment spacecraft, launched April 24, 1996, is expected to have a 5 year useful lifetime with a 12 month lifetime for the cryogenically cooled IR sensor. A pre-launch, ground based calibration of the instruments provided a basis for the pre-launch certification of the Level 2 data base these instruments produce. With the spacecraft in-orbit the certification of the instrument's Level 2 data base is being extended to the in-orbit environment.

Pollock, David B.↗

NASA NTRS1995

Zoom Lens Calibration for Wind Tunnel Measurements

This report summarizes an investigation of zoom lens calibration, with emphasis on the effects of lens-image-plane misalignment. Measurements have been made of the photogrammetric principal point and radial (symmetrical) and decentering (asymmetrical) distortion components as a function of the principal distance (zoom setting) of several zoom lenses. Data were also taken with the axis of symmetry (optical axis) of a zoom lens aligned and misaligned to the same solid-state video camera. An explanation is offered regarding the variation of the principal point as a function of zoom setting based on these measurements. In addition the relationship of the decentering distortion to radial distortion, principal distance, and lens-image-plane misalignment angle is discussed. A technique for determining the proper point of symmetry to be used for distortion computations (as opposed to the principal point) is also suggested. A simple technique for measuring the misalignment angle of zoom lenses when attached to video cameras is presented, along with measurements for seven solid-state cameras. A method to reduce the additional error introduced by zoom lens misalignment is presented. The implications of this study are that special measures to properly align a zoom lens to the sensor image plane are probably not necessary, but that as the accuracy obtainable in digital photogrammetry approaches the 0.01 or less pixel level, additional calibration including the point of symmetry for distortion computation should be considered.

Burner, A. W.↗

NASA NTRS2007

Microsystems, Space Qualified Electronics and Mobile Sensor Platforms for Harsh Environment Applications and Planetary Exploration

NASA Glenn Research Center is presently developing and applying a range of sensor and electronic technologies that can enable future planetary missions. These include space qualified instruments and electronics, high temperature sensors for Venus missions, mobile sensor platforms, and Microsystems for detection of a range of chemical species and particulates. A discussion of each technology area and its level of maturity is given. It is concluded that there is a strong need for low power devices which can be mobile and provide substantial characterization of the planetary environment where and when needed. While a given mission will require tailoring of the technology for the application, basic tools which can enable new planetary missions are being developed.

Hunter, Gary W.↗