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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 1,315 records · Page 73
All sourcesNASA NTRSDOE OSTI
NASA NTRS1984

Identification of two hard X-ray emitting Be stars using the HEAO 1 scanning modulation collimator

Using precise positions from the HEAO 1 Scanning Modulation Collimator experiment, two hard X-ray sources, 4U 0728 - 25 = 3A 0726 - 260 and 4U 2206 + 54 = 3A 2206 + 543, are identified with early-type stars. In both cases broad (10 A FWHM) H-alpha emission is detected. The UBV colors suggest that the optical counterparts are main-sequence B0-B2 stars at 2-6 kpc, implying a mean X-ray luminosity of order 10 to the 35th ergs/sq cm s (2-10 keV). The X-ray emission in both cases is highly variable, and it is suggested that they belong to the class of X-ray emitting Be stars, containing a neutron star in a widely separated binary system.

Steiner, J. E.↗
DOE OSTI2019

PBX-9501 High Explosive Infrared Thermography Test Report

High explosive safety requirements put in place by the Department of Defense necessitate that Los Alamos National Laboratory verify that high melting explosive-based plastic bonded explosive 9501 will not present a health or safety risk to personnel when exposed to various accident scenarios. The JT5R-14C test is being developed to validate this requirement in a scenario where PBX-9501 is exposed to a hydrocarbon fuel fire. Preliminary testing is required to establish benchmark data on the burning characteristics of PBX-9501. The PBX-9501 High Explosive Infrared Thermography test was designed to provide the benchmark burning characteristics of PBX-9501 in a simulated fuel fire environment using propane burners as a fuel source. The PBX-9501-HEIT was successfully completed using a 20.32 cm tall cylindrical sample of PBX-9501 with a radius of 10.16 cm, a volume of 6,589.63 cm 3 , a density of 1.83 g/cm 3 , and a mass of 1.2 kg. The PBX-9501-HEIT test was captured and recorded video sequence using a Telops Inc., Multispectral Infrared camera. The infrared sequence was reviewed to identify key events throughout the test and serves as a visual tool to cross reference against future testing to aid in the identification of PBX-9501 high explosive ignition and deflagration characteristics. The data obtained in the thermographic sequence confirmed that the temperatures emitted by the PBX-9501 were higher than the temperatures of the propane burner ignition source. The propane burner flames had a temperature range of 700-850 °C. The cylindrical sample of PBX-9501 burned at an average temperature of 1000-1200 °C on the surface with off-gassing temperatures averaging 1100-1250 °C. The heat map of the PBX-9501 obtained through the test was between 250-550 °C higher than the propane gas temperatures. The temperature differential between the PBX-9501 and the propane flame allowed for the identification of key burning features.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗
DOE OSTI2024

Machine learning enables identification of an alternative yeast galactose utilization pathway

How genomic differences contribute to phenotypic differences is a major question in biology. The recently characterized genomes, isolation environments, and qualitative patterns of growth on 122 sources and conditions of 1,154 strains from 1,049 fungal species (nearly all known) in the yeast subphylum Saccharomycotina provide a powerful, yet complex, dataset for addressing this question. We used a random forest algorithm trained on these genomic, metabolic, and environmental data to predict growth on several carbon sources with high accuracy. Known structural genes involved in assimilation of these sources and presence/absence patterns of growth in other sources were important features contributing to prediction accuracy. By further examining growth on galactose, we found that it can be predicted with high accuracy from either genomic (92.2%) or growth data (82.6%) but not from isolation environment data (65.6%). Prediction accuracy was even higher (93.3%) when we combined genomic and growth data. After the GALactose utilization genes, the most important feature for predicting growth on galactose was growth on galactitol, raising the hypothesis that several species in two orders, Serinales and Pichiales (containing the emerging pathogen Candida auris and the genus Ogataea, respectively), have an alternative galactose utilization pathway because they lack the GAL genes. Growth and biochemical assays confirmed that several of these species utilize galactose through an alternative oxidoreductive D-galactose pathway, rather than the canonical GAL pathway. Machine learning approaches are powerful for investigating the evolution of the yeast genotype–phenotype map, and their application will uncover novel biology, even in well-studied traits.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS1972

Analysis of instrumentation error effects on the identification accuracy of aircraft parameters

An analytical investigation is presented of the effect of unmodeled measurement system errors on the accuracy of aircraft stability and control derivatives identified from flight test data. Such error sources include biases, scale factor errors, instrument position errors, misalignments, and instrument dynamics. Two techniques (ensemble analysis and simulated data analysis) are formulated to determine the quantitative variations to the identified parameters resulting from the unmodeled instrumentation errors. The parameter accuracy that would result from flight tests of the F-4C aircraft with typical quality instrumentation is determined using these techniques. It is shown that unmodeled instrument errors can greatly increase the uncertainty in the value of the identified parameters. General recommendations are made of procedures to be followed to insure that the measurement system associated with identifying stability and control derivatives from flight test provides sufficient accuracy.

Sorensen, J. A.↗
NASA NTRS2007

Design and Simulation of a MEMS Structure for Electrophoretic and Dielectrophoretic Separation of Particles by Contactless Electrodes

Rapid identification of pathogenic bacterial species is an important factor in combating public health problems such as E. coli contamination. Food and waterborne pathogens account for sickness in 76 million people annually (CDC). Diarrheagenic E. coli is a major source of gastrointestinal illness. Severe sepsis and Septicemia within the hospital environment are also major problems. 75 1,000 cases annually with a 30-50% mortality rate (Crit Care Med, July '01, Vol. 29, 1303-10). Patient risks run the continuum from fever to organ failure and death. Misdiagnosis or inappropriate treatment increases mortality. There exists a need for rapid screening of samples for identification of pathogenic species (Certain E. coli strains are essential for health). Critical to the identification process is the ability to isolate analytes of interest rapidly. This poster discusses novel devices for the separation of particles on the basis of the dielectric properties, mass and surface charge characteristics is presented. Existing designs involve contact between electrode surfaces and analyte medium resulting in contamination of the electrode bearing elements Two different device designs using different bulk micromachining MEMS processes (PolyMUMPS and a PyrexBIGold electrode design) are presented. These designs cover a range of particle sizes from small molecules through eucaryotic cells. The application of separation of bacteria is discussed in detail. Simulation data for electrostatic and microfluidic characteristics are provided. Detailed design characteristics and physical features of the as fabricated PolyMUMPS design are provided. Analysis of the simulation data relative to the expected performance of the devices will be provided and subsequent conclusions discussed.

Shaw, Harry C.↗
DOE OSTI2014

UHE neutrino and cosmic ray emission from GRBs: Revising the models and clarifying the cosmic ray-neutrino connection

Gamma-ray bursts (GRBs) have long been held as one of the most promising sources of ultra-high energy (UHE) neutrinos. The internal shock model of GRB emission posits the joint production of UHE cosmic rays (UHECRs, above 10{sup 8} GeV), photons, and neutrinos, through photohadronic interactions between source photons and magnetically-confined energetic protons, that occur when relativistically-expanding matter shells loaded with baryons collide with one another. While neutrino observations by IceCube have now ruled out the simplest version of the internal shock model, we show that a revised calculation of the emission, together with the consideration of the full photohadronic cross section and other particle physics effects, results in a prediction of the prompt GRB neutrino flux that still lies one order of magnitude below the current upper bounds, as recently exemplified by the results from ANTARES. In addition, we show that by allowing protons to directly escape their magnetic confinement without interacting at the source, we are able to partially decouple the cosmic ray and prompt neutrino emission, which grants the freedom to fit the UHECR observations while respecting the neutrino upper bounds. Finally, we briefly present advances towards pinning down the precise relation between UHECRs and UHE neutrinos, including the baryonic loading required to fit UHECR observations, and we will assess the role that very large volume neutrino telescopes play in this.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2014

ON DISCOVERING ELECTROMAGNETIC EMISSION FROM NEUTRON STAR MERGERS: THE EARLY YEARS OF TWO GRAVITATIONAL WAVE DETECTORS

We present the first simulation addressing the prospects of finding an electromagnetic (EM) counterpart to gravitational wave (GW) detections during the early years of only two advanced detectors. The perils of such a search may have appeared insurmountable when considering the coarse ring-shaped GW localizations spanning thousands of square degrees using time-of-arrival information alone. Leveraging the amplitude and phase information of the predicted GW signal narrows the localization to arcs with a median area of only a few hundred square degrees, thereby making an EM search tractable. Based on the locations and orientations of the two LIGO detectors, we find that the GW sensitivity is limited to only two of the four sky quadrants. Thus, the rates of GW events with two interferometers is only ≈40% of the rate with three interferometers of similar sensitivity. Another important implication of the sky quadrant bias is that EM observatories in North America and Southern Africa would be able to systematically respond to GW triggers several hours sooner than Russia and Chile. Given the larger sky areas and the relative proximity of detected mergers, 1 m class telescopes with very wide-field cameras are well-positioned for the challenge of finding an EM counterpart. Identification of the EM counterpart amidst the larger numbers of false positives further underscores the importance of building a comprehensive catalog of foreground stellar sources, background active galactic nucleus and potential host galaxies in the local universe. This initial study is based on a small sample of 17 detected mergers; future works will expand this sample.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2016

Analysis of key safety metrics of thorium utilization in LWRs

Here, thorium has great potential to stretch nuclear fuel reserves because of its natural abundance and because it is possible to breed the 232 Th isotope into a fissile fuel ( 233 U). Various scenarios exist for utilization of thorium in the nuclear fuel cycle, including use in different nuclear reactor types (e.g., light water, high-temperature gas-cooled, fast spectrum sodium, and molten salt reactors), along with use in advanced accelerator-driven systems and even in fission-fusion hybrid systems. The most likely near-term application of thorium in the United States is in currently operating light water reactors (LWRs). This use is primarily based on concepts that mix thorium with uranium (UO 2 + ThO 2 ) or that add fertile thorium (ThO 2 ) fuel pins to typical LWR fuel assemblies. Utilization of mixed fuel assemblies (PuO 2 + ThO 2 ) is also possible. The addition of thorium to currently operating LWRs would result in a number of different phenomenological impacts to the nuclear fuel. Thorium and its irradiation products have different nuclear characteristics from those of uranium and its irradiation products. ThO 2 , alone or mixed with UO 2 fuel, leads to different chemical and physical properties of the fuel. These key reactor safety–related issues have been studied at Oak Ridge National Laboratory and documented in “Safety and Regulatory Issues of the Thorium Fuel Cycle” (NUREG/CR-7176, U.S. Nuclear Regulatory Commission, 2014). Various reactor analyses were performed using the SCALE code system for comparison of key performance parameters of both ThO 2 + UO 2 and ThO 2 + PuO 2 against those of UO 2 and typical UO 2 + PuO 2 mixed oxide fuels, including reactivity coefficients and power sharing between surrounding UO 2 assemblies and the assembly of interest. The decay heat and radiological source terms for spent fuel after its discharge from the reactor are also presented. Based on this evaluation, potential impacts on safety requirements and identification of knowledge gaps that require additional analysis or research to develop a technical basis for the licensing of thorium fuel are identified.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2014

Approaches to advancescientific understanding of macrosystems ecology

Macrosystem ecological studies inherently investigate processes that interact across multiple spatial and temporal scales, requiring intensive sampling and massive amounts of data from diverse sources to incorporate complex cross-scale and hierarchical interactions. Inherent challenges associated with these characteristics include high computational demands, data standardization and assimilation, identification of important processes and scales without prior knowledge, and the need for large, cross-disciplinary research teams that conduct long-term studies. Therefore, macrosystem ecology studies must utilize a unique set of approaches that are capable of encompassing these methodological characteristics and associated challenges. Several case studies demonstrate innovative methods used in current macrosystem ecology studies.

data management↗
NASA NTRS1983

An extensive galactic search for conformer II glycine

The most extensive galactic search reported to date for conformer II glycine, a higher energy form of the simplest amino acid has been conducted. The search utilized four glycine transitions at centimeter wavelengths and 21 at millimeter wavelengths to observe 18 galactic molecular sources and one comet. No conformer II glycine lines were detected, and measurements of representative sources were used to compute upper limits on total column densities. Several unidentified lines were detected and are reported here with some suggested possible identifications.

Snyder, L. E.↗
NASA NTRS1989

X rays from G54.1+0.3

Einstein IPC observations obtained on May 7, 1980 have detected an X-ray emission from G54.1+0.3. The results supports the identification of this object as a Crab-like SNR. The interstellar absorption is found to be high, suggesting a large distance to the source.

Seward, F. D.↗
NASA NTRS1989

The Einstein All-Sky IPC slew survey

The construction of the Einstein All-Sky Imaging Proportional Counter (IPC) slew survey is considered. It contains approximately 1000 sources between 10(exp -12) and 10(exp -10) erg/sq cm/s with a concentration toward the ecliptic poles and away from the galactic plane. Several sizable samples of bright soft X-ray selected objects for follow-up ROSAT and ASTRO-D observations and statistical study are presented. The survey source list is expected to be available by late 1989. Both paper and remote access online data base versions are to be available. An identification program is considered.

Elvis, Martin↗
NASA NTRS1997

Study of SRM Critical Surfaces Using Near Infrared Optical Fiber Spectrometry

The measurement and control of cleanliness for critical surfaces during manufacturing and in service operations provides a unique challenge in the current thrust for environmentally benign processes. Of particular interest has been work performed in maintaining quality in the production of bondline surfaces in propulsion systems and the identification of possible contaminants which are detrimental to the integrity of the bondline. This work requires an in-depth study of the possible sources of contamination, methodologies to identify contaminants, discrimination between contaminants and chemical species caused by environment, and the effect of particular contaminants on the bondline integrity of the critical surfaces. This paper will provide an introduction to the use of Near Infrared (NIR) optical fiber spectrometry in a nondestructive measurement system for process monitoring and how it can be used to help clarify issues concerning surface chemistry. In a previous conference, experimental results for quantitative measurement of silicone and Conoco HD2 greases, and tape residues on solid rocket motor surfaces were presented. This paper will present data for metal hydroxides and discuss the use of the integrating sphere to minimize the effects of physical properties of the surfaces (such as surface roughness) on the results obtained from the chemometric methods used for quantitative analysis.

Workman, G. L.↗
NASA NTRS2002

General Aviation Interior Noise: Noise Control Measure Evaluation - Part 3

The work reported herein is an extension to the work accomplished under NASA Grant NAG1-2091 on the development of noise/source/path identification techniques for single engine propeller driven General Aviation aircraft. The previous work developed a Conditioned Response Analysis (CRA) technique to identify potential noise sources that contributed to the dominating tonal responses within the aircraft cabin. The objective of the present effort was to improve and verify the findings of the CRA and develop and demonstrate noise control measures for single engine propeller driven General Aviation aircraft.

Unruh, James F.↗
NASA NTRS1987

Structural Diagnosis

All over the world, officials charged with preserving historical structures are faced with a problem of environmental contamination of building materials that cause structural deterioration. First requisite for preserving the structure is identification of the nature of contaminants. A "non-invasive"technique based on space technology has been developed and tested. It employs a neutron source and a gamma ray detector. Placed on one side of the wall to be examined, the source fires neutrons created by the decay of a radioactive isotope. As they pass through the wall, the neutrons collide with atoms and the atoms, depending on their type, emit various kinds of gamma rays. These rays are identified by the gamma ray detector on the other side of the wall. Energy of the rays shows the kind of element present. The intensity level indicates the quantity. Composition of the contaminants within the walls is determined by a multichannel analyzer.

Source record↗
NASA NTRS2007

NASA Tech Briefs, June 2007

Topics covered include: High-Accuracy, High-Dynamic-Range Phase-Measurement System; Simple, Compact, Safe Impact Tester; Multi-Antenna Radar Systems for Doppler Rain Measurements; 600-GHz Electronically Tunable Vector Measurement System; Modular Architecture for the Measurement of Space Radiation; VLSI Design of a Turbo Decoder; Architecture of an Autonomous Radio Receiver; Improved On-Chip Measurement of Delay in an FPGA or ASIC; Resource Selection and Ranking; Accident/Mishap Investigation System; Simplified Identification of mRNA or DNA in Whole Cells; Printed Multi-Turn Loop Antennas for RF Biotelemetry; Making Ternary Quantum Dots From Single-Source Precursors; Improved Single-Source Precursors for Solar-Cell Absorbers; Spray CVD for Making Solar-Cell Absorber Layers; Glass/BNNT Composite for Sealing Solid Oxide Fuel Cells; A Method of Assembling Compact Coherent Fiber-Optic Bundles; Manufacturing Diamond Under Very High Pressure; Ring-Resonator/Sol-Gel Interferometric Immunosensor; Compact Fuel-Cell System Would Consume Neat Methanol; Algorithm Would Enable Robots to Solve Problems Creatively; Hypothetical Scenario Generator for Fault-Tolerant Diagnosis; Smart Data Node in the Sky; Pseudo-Waypoint Guidance for Proximity Spacecraft Maneuvers; Update on Controlling Herds of Cooperative Robots; and Simulation and Testing of Maneuvering of a Planetary Rover.

Source record↗
NASA NTRS2009

A 20 Year Lifecycle Study for Launch Facilities at the Kennedy Space Center

The lifecycle cost analysis was based on corrosion costs for the Kennedy Space Center's Launch Complexes and Mobile Launch Platforms. The first step in the study involved identifying the relevant assets that would be included. Secondly, the identification and collection of the corrosion control cost data for the selected assets was completed. Corrosion control costs were separated into four categories. The sources of cost included the NASA labor for civil servant personnel directly involved in overseeing and managing corrosion control of the assets, United Space Alliance (USA) contractual requirements for performing planned corrosion control tasks, USA performance of unplanned corrosion control tasks, and Testing and Development. Corrosion control operations performed under USA contractual requirements were the most significant contributors to the total cost of corrosion. The operations include the inspection of the pad, routine maintenance of the pad, medium and large scale blasting and repainting activities, and the repair and replacement of structural metal elements. Cost data was collected from the years between 2001 and 2007. These costs were then extrapolated to future years to calculate the 20 year lifecycle costs.

Kolody, Mark R.↗
DOE OSTI2019

Online Static Load Model Estimation in Distribution Systems: Preprint

The paper focuses on parameter identification for time varying voltage dependent polynomial load models, namely the constant impedance (Z), constant current (I), and constant power (P), in the distribution systems. Typically, parameter identification has been done for aggregated loads at substations for the transmission planning studies. Given the higher voltage volatility faced by active distribution systems, this paper takes the load model estimation to the distribution networks. The paper assumes the presence of measurements at the distribution nodes from various sources, each at varying temporal resolutions. Least squares estimation (LSE) method with bounded variables is used to convert the measurements into ZIP parameter estimations for loads at various locations of the feeder. The results and discussions focus on some of the estimation issues faced in a distribution system due to varying voltage sensitivities of loads along a feeder, measurement resolution, impact of window size and sampling rate of measurement data, and the use of dynamic simulations to create synthetic measurement data in the absence of real ones.

24 POWER TRANSMISSION AND DISTRIBUTION↗