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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 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
NASA NTRS1995

Using IRI for the computation of ionospheric corrections for altimeter data analysis

Measurements by single-frequency satellite altimeter (Geosat, ERS-1) require a ionospheric correction to account for the signal time delay in the ionosphere. We propose using the International Reference Ionosphere (IRI) for the determination of this time delay. To investigate the effectiveness of an IRI correction, we have compared the IRI values with ionospheric corrections deduce from measurements by the dual-frequency Topex altimeter. By measuring at two frequencies, the Topex instrument can record (and thus eliminate) the ionospheric influence. We find that IRI agrees with the Topex data much better than the model that is currently used in Geosat data analysis. In particular the earlier model does not represent the equatorial double-peak (equator anomaly) clearly seen in the Topex data. Overall, the use of IRI results in a 30% improvement (over the older model) in the accuracy of ionospheric corrections computed for the first year of the Topex mission.

Bilitza, D.↗
NASA NTRS1997

Pioneer 10 and 11 Data Analysis

This report finishes the work of NASA Grant NAS2-153, which supported data analysis for the UCSD instruments on Pioneers 10 and 11. The data analyzed under this grant span 22 years of interplanetary measurements in the inner and outer heliosphere. The UCSD instruments made their mark in cosmic ray research based upon their high energy thresholds, directional responses, and reliable data streams. one of their primary scientific objectives concerns the size, configuration, and time behavior of the heliosphere. The size scale is inferred from the radial intensity gradient, which is measured between the two spacecraft and extrapolated to interstellar intensity levels at the cosmic ray modulation boundary. This boundary still eludes us, and its position, motion, and the best method of extrapolation are ongoing problems. Current projections place the boundary beyond 100 AU, which may be beyond the termination shock, and raises the question of possible modulation in the heliosheath. Probably our only hope of seeing this region in the immediate future rides on the possibility that the boundary will move inward. Our instruments have recorded many Forbush, or transient, decreases in the outer heliosphere. These observations led us to a model that attributes many of the decreases to solar wind stream-stream interactions, and relates the cosmic ray variations to the locally observed magnetic field magnitude. As the cosmic ray variations in this model result only from topological changes in the modulation integral, the model is a tool for studying the possibility that the 11 year cosmic ray modulation cycle can be accounted for by a superposition of Forbush decreases. The cosmic ray angular distribution function is measurable, given a good telemetry rate, by the UCSD Cerenkov detector which counts particles of energy greater than 500 MeV/n. We obtained statistically significant samples from 1 to 9 AU, at 13 AU, and at 34 AU. The anisotropy tends to be a few tenths of a per cent at all radial distances. A quasiperiodic variation in the east-west anisotropy with period of about 50 days remains unexplained.

Fillius, Walker↗
NASA NTRS1999

Aircraft as Research Tools

Aeronautical research usually begins with computers, wind tunnels, and flight simulators, but eventually the theories must fly. This is when flight research begins, and aircraft are the primary tools of the trade. Flight research involves doing precision maneuvers in either a specially built experimental aircraft or an existing production airplane that has been modified. For example, the AD-1 was a unique airplane made only for flight research, while the NASA F-18 High Alpha Research Vehicle (HARV) was a standard fighter aircraft that was transformed into a one-of-a-kind aircraft as it was fitted with new propulsion systems, flight controls, and scientific equipment. All research aircraft are able to perform scientific experiments because of the onboard instruments that record data about its systems, aerodynamics, and the outside environment. Since the 1970's, NASA flight research has become more comprehensive, with flights involving everything form Space Shuttles to ultralights. NASA now flies not only the fastest airplanes, but some of the slowest. Flying machines continue to evolve with new wing designs, propulsion systems, and flight controls. As always, a look at today's experimental research aircraft is a preview of the future.

Source record↗
NASA NTRS2008

Commodity-Free Calibration

Commodity-free calibration is a reaction rate calibration technique that does not require the addition of any commodities. This technique is a specific form of the reaction rate technique, where all of the necessary reactants, other than the sample being analyzed, are either inherent in the analyzing system or specifically added or provided to the system for a reason other than calibration. After introduction, the component of interest is exposed to other reactants or flow paths already present in the system. The instrument detector records one of the following to determine the rate of reaction: the increase in the response of the reaction product, a decrease in the signal of the analyte response, or a decrease in the signal from the inherent reactant. With this data, the initial concentration of the analyte is calculated. This type of system can analyze and calibrate simultaneously, reduce the risk of false positives and exposure to toxic vapors, and improve accuracy. Moreover, having an excess of the reactant already present in the system eliminates the need to add commodities, which further reduces cost, logistic problems, and potential contamination. Also, the calculations involved can be simplified by comparison to those of the reaction rate technique. We conducted tests with hypergols as an initial investigation into the feasiblility of the technique.

Source record↗
NASA NTRS2017

Validation of a Thermo-Ablative Model of Elastomeric Internal Insulation Materials

In thermo-ablative material modeling, as in many fields of analysis, the quality of the existing models significantly exceeds that of the experimental data required for their validation. In an effort to narrow this gap, a laboratory-scale internal insulation test bed was developed that exposes insulation samples to realistic solid rocket motor (SRM) internal environments while being instrumented to record real-time rates of both model inputs (i.e., chamber pressure, total surface heat flux, and radiative heat flux) as well as model outputs (i.e., material decomposition depths (MDDs) and in-depth material temperatures). In this work, the measured SRM internal environment parameters were used in conjunction with equilibrium thermochemistry codes as inputs to one-dimensional thermo-ablative models of the PBINBR and CFEPDM insulation samples used in the lab-scale test firings. The computed MDD histories were then compared with those deduced from real-time X-ray radiography of the insulation samples, and the calculated in-depth temperatures were compared with those measured by embedded thermocouples. The results of this exercise emphasize the challenges of modeling and testing elastomeric materials in SRM environments while illuminating the path forward to improved fidelity.

Martin, Heath T.↗
NASA NTRS2018

Microwave Remote Sensing of Snow: Advances over Ice Sheet, Land, and Sea Ice

Satellite microwave radiometers have enabled us to observe the cryosphere and its changes. A variety of algorithms have been developed since the late 1970s. These convert observed microwave radiation into geophysical, glaciological properties relevant to study ice sheets’ snow accumulation and melt, terrestrial snow water equivalent and freeze/thaw state, and various sea ice cover characteristics like extent, concentration, and thickness. In spite of the continuous availability of satellite microwave radiometers for the past 40 years, potential for advancing our understanding of the relationship between microwave radiation and snow/ice properties still exists. Original empirical algorithms have matured and are becoming more physically based. This presentation offers insights into some advances made during the past 10 years in monitoring ice sheet, terrestrial snow, and sea ice. These advances made it possible to provide new, more reliable climate-related variables to the community for the satellite era using the typical 18-37 GHz frequency range (e.g., retrievals of grain size profiles in Antarctica, snow cover stratification, and therefore accumulation with applications to climate studies). Recent NASA instruments have recorded low microwave frequencies (at 1.4 GHz). These observations have a large penetration depth, they emanate from deep into the ice, where properties including temperature are very stable. Nonetheless, it has been found at both Dome C, Antarctica and Summit, Greenland that changes in surface snow properties significantly influence these observations. Compared to ice sheets, terrestrial snow and sea ice present higher spatial heterogeneities. Over land, presence of canopy and lakes, though with known locations, add ambiguities in the retrievals of snow properties. Over sea ice, ridges, leads, changes in salinity, and sea ice drift augment further the level of difficulty in obtaining robust geophysical properties. Assessing the quality of satellite retrievals, often requiring field activities, is a necessary step in designing the next generation of microwave algorithms to monitor changes in the cryosphere.

Brucker, Ludovic↗
DOE OSTI2020

Development of a Testbed for Pipeline Flushing - 20425

Pipelines which carry high-level waste within the DOE complex should be properly flushed in the cases where stationary or moving beds of solid sediment occur, or lines are prone to hydrogen gas buildup. Present guidelines establish a minimum for the amount of water (flush volume) and flush velocity values used for post-transfer flushing operations to achieve satisfactory cleaning of pipelines. However, further studies are needed to find optimal operating velocity modes/values in order to minimizing the flush volume and consequent downstream waste. These efforts are significantly helpful to DOE waste remediation sites by preserving tank storage, preventing additional waste processing, and minimizing dilution and changes in waste chemistry. An experimental test loop was recently developed for study of non-Newtonian slurry flushing at the Florida International University (FIU). This loop was designed to create sediment beds of various materials and bed heights and investigate parameters that effect the efficiency of flushing operations. The objective is to find flush velocity values/modes which lead to satisfactory cleaning of transport lines with a minimum amount of water usage. A 165 ft experimental test loop made of 3-inch carbon steel pipes was constructed and used in initial testing campaigns. This pipe loop was equipped with real-time monitoring instruments to record variation of pressure, density, mass flow rate, and temperature during testing. Post-flush in-situ no-flow evaluations were performed using ultrasonic, endoscopy, and visual inspection. Additional post-flush evaluations were conducted using filtration and density monitoring of residuals within a designated circulations loop. These provisions enable comparison of pipeline cleanness before the start and after termination of flushing operations for efficiency evaluation. This paper presents efforts associated with flushing of kaolin-water mixtures at different concentrations and with various flush volume and flush velocity values/modes. In initial testing, efforts focused on creating repeatable sediment beds inside the pipeline in both fully-flooded (no pre-flush drainage) and gravity-drained (pre-flush drained) systems. Bed characterization (i.e., measurement of sediment height and solids concentration) was conducted to ensure about consistency of initial conditions between tests. Preliminary results for flushing study of 10% vol. kaolin-water mixtures starting from a fully-flooded initial condition showed that flushing with 1-line volume (65 gallons) could remove up to 72 percent of solids from the pipeline. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
NASA NTRS2001

Searching for the Beginning of the Ozone Turnaround Using a 22-Year Merged Satellite Data Set

We have used the data from six satellite instruments that measure the total column amount of ozone to construct a consistent merged data set extending from late 1978 into 2000. The keys to constructing a merged data set are to minimize potential drift of individual instruments and to accurately establish instrument-to-instrument offsets. We have used the short-wavelength D-pair measurements (306nm-313nm) of the SBUV and SBUV/2 instruments near the equator to establish a relatively drift-free record for these instruments. We have then used their overlap with the Nimbus 7 and EP TOMS instruments to establish the relative calibration of the various instruments. We have evaluated the drift uncertainty in our merged ozone data (MOD) set by examining both the individual instrument drift uncertainty and the uncertainty in establishing the instrument- to-instrument differences. We conclude that the instrumental drift uncertainty over the 22-year data record is 0.9 %/decade (2-sigma). We have compared our MOD record with 37 ground stations that have a continuous record over that time period. We have a mean drift with respect to the stations of +0.3 %/decade which is within 1-sigma of our uncertainty estimate. Using the satellite record as a transfer standard, we can estimate the capability of the ground instruments to establish satellite calibration. Adding the statistical variability of the station drifts with respect to the satellite to an estimate of the overall drift uncertainty of the world standard instrument, we conclude that the stations should be able to be used to establish the drift of the satellite data record to within and uncertainty of 0.6 %/decade (2-sigma). Adding to this an uncertainty due to the-incomplete global coverage of the stations, we conclude that the station data should be able to establish the global trend with an uncertainty of about 0.7 %/decade, slightly better than for the satellite record. We conclude that merging the two records together gives only a slight improvement in the uncertainty. Keeping them separate gives the greater confidence of two independent measures of the ozone trend and potential recovery. We fit the trend in our MOD record through May of 1991 and then extrapolated forward to see if the data at the end of the record was above the statistical model as a measure of ozone recovery as was done in the last WMO/UNEP assessment report. Because our data set drifts with respect to the ground-stations through May of 1991, we calculated a smaller global trend (-1.1 %/decade) than in the WMO/UNEP report. Our data in 1998 and 1999 was, on average 2 DU above the extrapolated statistical model with a 2-sigma uncertainty of 6 DU. For the combined mid-latitudes of the northern and southern hemispheres, the data was 5 DU above the extrapolated statistical model with a 2-sigma uncertainty of 10 DU. These may be signs of recovery, but they are still statistically insignificant.

Stolarski, Richard S.↗
DOE OSTI2020

Fireworks on Weather Radar and Camera

High-sensitivity weather radars easily detect nonmeteorological phenomena characterized by weak radar returns. Fireworks are the example presented here. To understand radar observations, an experiment was conducted in which the National Severe Storms Laboratory (NSSL)’s research (3-cm wavelength) dual-polarization radar and a video camera were located at 1 km from fireworks in Norman, Oklahoma. The fireworks from the 4 July 2017 celebration were recorded by both instruments. The experiment is described. Few bursts recorded by the camera are analyzed to obtain the height of the explosion, its maximum diameter, number of stars, and the duration of the visible image. Radar volume scans are examined to characterize the height of the observation, the maximum reflectivity, and its distribution with height. The fireworks location is close to the Terminal Doppler Weather Radar (TDWR) that operates in single polarization at a 5-cm wavelength and monitors hazardous weather over the Oklahoma City airport. A third radar with data from the event is the Weather Surveillance Radar-1988 Doppler (WSR-88D) located in Norman. It has a wavelength of 10 cm and supports technical developments at the Radar Operation Center. Reflectivity factors measured by the three radars are compared to infer the size of dominant scatterers. The polarimetric characteristics of fireworks returns are analyzed. Although these differ from those of precipitation, they are indistinguishable from insect returns. Radar observation of larger fireworks in Fort Worth, Texas, with a WSR-88D is included and compared with the observations of the smaller fireworks in Norman. We expect the detectability of explosions would be similar as of fireworks. Pinpointing locations would be useful to first responders, or air quality forecasters. We note a benefit of fireworks recognition in weather radar data is that it can prevent contamination of precipitation accumulations.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1981

In-flight direct-strike lightning research

Tests designed to investigate the lightning-generated electromagnetic environment affecting aircraft are discussed. An F-106B aircraft specially instrumented for lightning electromagnetic measurements was used. The instrumentation system is reviewed and typical results recorded by the instrumentation during simulated-lightning ground tests performed for a safety survey are presented. Several examples of data obtained during summer flight testing are presented and future plans are discussed.

Pitts, F. L.↗
NASA NTRS1995

Active Flow Control: Instrumentation Automation and Experimental Technique

In investigating the potential of a new actuator for use in an active flow control system, several objectives had to be accomplished, the largest of which was the experimental setup. The work was conducted at the NASA Langley 20x28 Shear Flow Control Tunnel. The actuator named Thunder, is a high deflection piezo device recently developed at Langley Research Center. This research involved setting up the instrumentation, the lighting, the smoke, and the recording devices. The instrumentation was automated by means of a Power Macintosh running LabVIEW, a graphical instrumentation package developed by National Instruments. Routines were written to allow the tunnel conditions to be determined at a given instant at the push of a button. This included determination of tunnel pressures, speed, density, temperature, and viscosity. Other aspects of the experimental equipment included the set up of a CCD video camera with a video frame grabber, monitor, and VCR to capture the motion. A strobe light was used to highlight the smoke that was used to visualize the flow. Additional effort was put into creating a scale drawing of another tunnel on site and a limited literature search in the area of active flow control.

Gimbert, N. Wes↗
NASA NTRS1968

Analysis of flutter in tape transport systems

Effect of flutter on digital data is recorded by magnetic tape recorders used with instrumentation systems. Major effect for both FM and direct recording techniques is shown to be a perturbation of the signal time base.

Davis, R. C.↗
NASA NTRS2022

Optimized Umkehr Profile Algorithm for Ozone Trend Analyses

The long-term record of Umkehr measurements from four NOAA Dobson spectrophotometers was reprocessed after updates to the instrument calibration procedures. In addition, a new data quality-control tool was developed for the Dobson automation software (WinDobson). This paper presents a comparison of Dobson Umkehr ozone profiles from NOAA ozone network stations (Boulder, OHP, MLO, Lauder) against several satellite records, including Aura Microwave Limb Sounder (MLS; ver. 4.2), and combined SBUV and OMPS records (NASA AGG and NOAA COH). A subset of satellite data is selected to match Dobson Umkehr observations at each station spatially (distance less than 200 km) and temporally (within 24 hours). Umkehr Averaging Kernels (AKs) are applied to vertically smooth all overpass satellite profiles prior to comparisons. The station Umkehr record consists of several instrumental records, which have different optical characterizations, and thus instrument-specific stray light contributes to the data processing errors and creates step changes in the record. This work evaluates the overall quality of Umkehr long-term measurements at NOAA ground-based stations and assesses the impact of the instrumental changes on the stability of the Umkehr ozone profile record. This paper describes a method designed to correct biases and discontinuities in the retrieved Umkehr profile that originate from the Dobson calibration process, repair, or optical realignment of the instrument. The M2GMI and GMI CTM ozone profile model output matched to station location and date of observation is used to evaluate instrumental step changes in the Umkehr record. Homogenization of the Umkehr record and discussion of the apparent stray light error in retrieved ozone profiles are the focus of this paper. Homogenization of ground-based records is of great importance for studies of long-term ozone trends and climate change.

Umkehr↗
NASA NTRS1924

Aeronautic instruments

The development of aeronautic instruments. Vibrations, rapid changes of the conditions of flight and of atmospheric conditions, influence of the air stream all call for particular design and construction of the individual instruments. This is shown by certain examples of individual instruments and of various classes of instruments for measuring pressure, change of altitude, temperature, velocity, inclination and turning or combinations of these.

INSTRUMENTS↗
NASA NTRS2006

Contributions of Satellite Observations to Understanding Climate Change

One of the challenges facing atmospheric scientists is to interpret trends in multi-decadal data records. Although data records from satellite instruments are not as long as some ground-based records, global coverage and resolved vertical profiles provide unique information for identifying signatures of climate change. For example, the Halogen Occultation Experiment (HALOE) on the Upper Atmosphere Research Satellite provided profiles of O3, H2O, HC1, HF, CH4 from October 1991 until November 2005. There are also multi-annual ground based measurements of the column HCl. Middle latitude ground-based measurements show a seasonal cycle, and the HALOE profiles show that this is driven by the seasonal change in the composition and mass of the region between the tropopause and 380K surface (the lowermost stratosphere). Understanding the processes that produce the seasonal cycle makes it possible to interpret a future change in the seasonal cycle as a marker of a change in the stratospheric residual circulation. Satellite observations have also provided key information for improving the physical basis of models used to predict future composition and climate circulation. An example is the "tape recorder" signature in tropical stratospheric water vapor, i.e., the slow ascent of high and low water vapor anomalies roughly corresponding to the tropopause temperature at the time air entered the stratosphere. This signature has become a key diagnostic of performance for climate models.

Douglass, Anne R.↗
NASA NTRS2012

On Shaft Data Acquisition System (OSDAS)

On Shaft Data Acquisition System (OSDAS) is a rugged, compact, multiple-channel data acquisition computer system that is designed to record data from instrumentation while operating under extreme rotational centrifugal or gravitational acceleration forces. This system, which was developed for the Heritage Fuel Air Turbine Test (HFATT) program, addresses the problem of recording multiple channels of high-sample-rate data on most any rotating test article by mounting the entire acquisition computer onboard with the turbine test article. With the limited availability of slip ring wires for power and communication, OSDAS utilizes its own resources to provide independent power and amplification for each instrument. Since OSDAS utilizes standard PC technology as well as shared code interfaces with the next-generation, real-time health monitoring system (SPARTAA Scalable Parallel Architecture for Real Time Analysis and Acquisition), this system could be expanded beyond its current capabilities, such as providing advanced health monitoring capabilities for the test article. High-conductor-count slip rings are expensive to purchase and maintain, yet only provide a limited number of conductors for routing instrumentation off the article and to a stationary data acquisition system. In addition to being limited to a small number of instruments, slip rings are prone to wear quickly, and introduce noise and other undesirable characteristics to the signal data. This led to the development of a system capable of recording high-density instrumentation, at high sample rates, on the test article itself, all while under extreme rotational stress. OSDAS is a fully functional PC-based system with 48 channels of 24-bit, high-sample-rate input channels, phase synchronized, with an onboard storage capacity of over 1/2-terabyte of solid-state storage. This recording system takes a novel approach to the problem of recording multiple channels of instrumentation, integrated with the test article itself, packaged in a compact/rugged form factor, consuming limited power, all while rotating at high turbine speeds.

Pedings, Marc↗