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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 541 records · Page 30
All sourcesNASA NTRSDOE OSTI
NASA NTRS1986

Fatigue behavior of flexhoses and bellows due to flow-induced vibrations

The analysis and results developed in a fresh approach to calculate flow induced vibration response of a flexible flow passage are summarized. The vibration results are further examined in the frequency domain to obtain dominant frequency information. A cumulative damage analysis due to cyclic strains is performed to obtain the number of cycles to failure for a metallic bellows of particular specifications under a variety of operational conditions. Sample plots of time and frequency domain responses are included. The complex listing of a computer program is provided. The program successively executes each of the analyses needed to calculate the vibration response, the frequency response, the cyclic strains and the number of cycles to failure. The program prompts the user for necessary input information. Sample data from the program is provided. The fatigue life results obtained by the computer model lie within an acceptable range of previously measured available data.

Desai, P. V.↗
NASA NTRS1987

Contamination control approach for the Extreme Ultraviolet Explorer satellite instrumentation

The Extreme Ultraviolet Explorer will perform an all-sky survey and spectroscopic observations over the wavelength range 80-900A. Hydrocarbon and particulate contamination will potentially affect the throughput and signal to noise ratio of the signal detected by the instruments. A witness sample program is here used to investigate and monitor the effects of specific contaminants on EUV reflectivity. Witness samples were intentionally contaminated with thin layers of pump oil. An oil layer 150 A thick was applied and found to evaporate over 8 hours. The EUV reflectivity and imaging properties were then measured and found to be acceptable for grazing angles between 5 and 30 deg. In a second test, layers 500 A thick were deposited and then allowed to evaporate in vacuum; once the oil had evaporated to at least 350 A, the final sample reflectivity was degraded less than 10 percent, but the image was degraded severely by scattering. An outline of the contamination control program is also presented.

Mrowka, Stan↗
DOE OSTI2016

Verification and Validation of CFD Simulations involving Twin Rectangular Jets using Steady RANS in Star-CCM+

Analyses such as component design and safety analysis can be conducted through careful application of computational fluid dynamics (CFD) codes. Before these codes can be considered ready for specific analysis, benchmarking (validation) against applicable datasets is needed. The twin jet water facility (TJWF) developed originally at the University of Tennessee, Knoxville has been purposed for aiding in this type of work. The TJWF allows for large data sets to be created using state of the art non-invasive measurement techniques within a mostly transparent testing volume. Utilizing velocity data collected in the TJWF by Wang et. al., the Star-CCM+ code was benchmarked a using steady Reynolds averaged Navier Stokes (RANS) framework for a combining two jet case. Careful efforts to properly conduct verification of the numerical work was undertaken with a sample reported in this summary. The computational results were validated against the experimental work and found to be within acceptable limits. The parameters of interest were the merging and combining points (MP and CP) of the twin jets, and the velocity profiles at increasing heights after injection. Fig.1 provides a graphical depiction of the twin jets combining within a free shear volume with key geometric factors included. The MP and velocity profiles were predicted with reasonable agreement. Whereas, the combining point of the twin jets was found to be over-predicted by {approx}24% difference. (authors)

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
NASA NTRS1992

Report on the international Cambodian crater expedition, 1992

It has been proposed that Tonle Sap, a lake in Cambodia, 100 km long and 30 km wide, marks the location of an elongate basin formed by the oblique impact of a comet or asteroid. The impact is considered to have produced melted ejecta found now as tektites over much of southeast Asia and Australia. The location of the lake, its approximate age, its size, and the orientation of its long axis (toward Australia) are consistent with this hypothesis. Our scientific objectives were to find impact or shock metamorphosed rocks unambiguously related to the Tonle Sap basin, to collect samples of rocks that may represent those melted to produce Australasian tektites, and to learn as much as possible about Cambodian geology. Using 1:200,000-scale geologic maps with fairly detailed descriptions of the rock units, we selected a number of acceptable 'phnoms' (hills that rise abruptly out of the surrounding plain) that may contain rocks affected by the postulated Tonle Sap impact. A map of central Cambodia is shown, and the locations of sites where samples were collected are indicated. A list of those sites, together with a description of the rocks reported to be present at each site, is given. No obviously shock-metamorphosed or suevite-like rocks were observed. Recent alluvium surrounding Tonle Sap is judged to be lake sediment deposited when the lake surface was at a higher elevation.

Hartung, J.↗
DOE OSTI2013

Dual-Remote Raman Technology for In-Situ Identification of Tank Waste

A new Raman spectroscopic system for in-situ identification of the composition of the solid nuclear tank waste is being developed by collaborative effort between Pacific Northwest National Laboratory (PNNL) and EIC, Inc. The recent advancements in the Raman technology allow probing the chemical composition of the tank waste without sample collection. In the newly tested configuration, the Raman probe is installed on the top of the tank riser and sends the incident laser beam to the bottom of the tank, 10 – 70 feet away. The returning light containing chemical information is collected by the Raman probe and transmits it via fiber optic cable to the spectrometer located outside the tank farm area. This dual remote technology significantly expands currently limited options for the safe rapid in-situ identification of the solid tank waste needed for the retrieval decisions. The developed Raman system was extensively tested for acceptability prior tank farm deployment. This testing included calibration of the system with the respect of the distance between the Raman probe and the sample, incident laser beam angle, and presence of the optical interferences. The Raman system was successfully deployed to C-111 tank at the US DOE Hanford site. As the result of this deployment, the composition of the hardpan at the bottom of C-111 tank was identified. Further development of the dual-remote Raman technology will provide a significant safety enhancement eliminating the potential of personnel radiation exposure associated with the grab sample collection and expands options of the rapid and cost-effective in-situ chemical analysis of the tank waste.

in-situ Hanford tank, Raman measurement↗
DOE OSTI2013

Dual-Remote Raman Technology for In-Situ Identification of Tank Waste - 13549

A new Raman spectroscopic system for in-situ identification of the composition of solid nuclear tank waste is being developed by collaborative effort between Pacific Northwest National Laboratory (PNNL) and EIC Laboratories, Inc. The recent advancements in Raman technology allow probing the chemical composition of the tank waste without sample collection. In the newly tested configuration, the Raman probe is installed on the top of the tank riser and sends the incident laser beam to the bottom of the tank, 10 - 70 feet away. The returning light containing chemical information is collected by the Raman probe and is transmitted via fiber optic cable to the spectrometer located outside the tank farm area. This dual remote technology significantly expands currently limited options for the safe rapid in-situ identification of the solid tank waste needed for the retrieval decisions. The developed Raman system was extensively tested for acceptability prior to tank farm deployment. This testing included calibration of the system with respect of the distance between the Raman probe and the sample, incident laser beam angle, and presence of the optical interferences. The Raman system was successfully deployed on Tank C-111 at the US DOE Hanford site. As the result of this deployment, the composition of the hardpan at the bottom of C-111 tank was identified. Further development of the dual-remote Raman technology will provide a significant safety enhancement eliminating the potential of personnel radiation exposure associated with the grab sample collection and expands options of the rapid and cost-effective in-situ chemical analysis of the tank waste. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
NASA NTRS2015

2014 ISS Potable Water Characterization and Continuation of the DMSD Chronicle

During 2014 the crews from Expeditions 38-41 were resident on the International Space Station (ISS). In addition to the U.S. potable water reclaimed from humidity condensate and urine, the other water supplies available for their use were Russian potable water reclaimed from condensate and Russian ground-supplied potable water. Beginning in June of 2014, and for the fourth time since 2010, the product water from the U.S. Water Processor Assembly (WPA) experienced a rise in the total organic carbon (TOC) level due to organic contaminants breaking through the water treatment process. Results from ground analyses of ISS archival water samples returned on Soyuz 38 confirmed that dimethylsilanediol (DMSD) was once again the contaminant responsible for the rise. With this confirmation in hand and based upon the low toxicity of DMSD, a waiver was approved to allow the crew to continue to consume the water after the TOC level exceeded the U.S. Segment limit of 3 mg/L. Several weeks after the WPA multifiltration beds were replaced, as anticipated based upon experience from previous rises, the TOC levels returned to below the method detection limit of the onboard TOC analyzer (TOCA). This paper presents and discusses the chemical analysis results for the ISS archival potable water samples returned in 2014 and analyzed by the Johnson Space Center's Toxicology and Environmental Chemistry laboratory. These results showed compliance with ISS potable water quality standards and indicated that the potable water supplies were acceptable for crew consumption. Although DMSD levels were at times elevated they remained well below the 35 mg/L health limit, so continued consumption of the U.S potable water was considered a low risk to crew health and safety. Excellent agreement between inflight and archival sample TOC data confirmed that the TOCA performed optimally and it continued to serve as a vital tool for monitoring organic breakthrough and planning remediation action.

Straub, John E., II↗
NASA NTRS2018

Meal Replacement Mass Reduction Integration and Acceptability Study

The Orion Multi-Purpose Crew Vehicle (MPCV) and future exploration missions are mass constrained; therefore we are challenged to reduce the mass of the food system by 10% while maintaining safety, nutrition, and acceptability to support crew health and performance for exploration missions. Meal replacement with nutritionally balanced, 700-900 calorie bars was identified as a method to reduce mass. However, commercially available products do not meet the requirements for a meal replacement in the spaceflight food system. The purpose of this task was to develop a variety of nutritionally balanced, high quality, breakfast replacement bars, which enable a 10% food mass savings. To date, six nutrient-dense meal replacement bars have been developed, all of which meet spaceflight nutritional, microbiological, sensory, and shelf-life requirements. The four highest scoring bars were evaluated based on final product sensory acceptability, nutritional stability, qualitative stability of analytical measurements (i.e. color and texture), and microbiological compliance over a period of two years to predict long-term acceptability. All bars maintained overall acceptability throughout the first year of storage, despite minor changes in color and texture. However, added vitamins C, B1, and B9 degraded rapidly in fortified samples of Banana Nut bars, indicating the need for additional development. In addition to shelf-life testing, four bar varieties were evaluated in the Human Exploration Research Analog (HERA), campaign 3, to assess the frequency with which actual meal replacement options may be implemented, based on impact to satiety and psychosocial measurements. Crewmembers (n=16) were asked to consume meal replacement bars every day for the first fifteen days of the mission and every three days for the second half of the mission. Daily surveys assessed the crew's responses to bar acceptability, mood, food fatigue and perceived stress. Preliminary results indicate that the majority of crew members were noncompliant with daily meal replacement during the first half of the mission. Several crew members chose to forgo the meal, resulting in caloric deficits that were higher on skipped-bar days. Body mass loss was significant throughout the mission. Although there was no significant difference in body mass loss overall between the first half and second half of the mission, a higher number of individual crew members lost more body mass in the first half of the mission. Analysis is still ongoing, but current trends suggest that daily involuntary meal replacement can lead to greater individual impacts on body mass and psychological factors, while meal replacement on a more limited basis may be acceptable to most crew for missions up to 30 days. This data should be considered in Orion mass trades with health and human performance.

Sirmons, T.↗
NASA NTRS1984

The rotation of small asteroids

The Binzel and Mulholland (1983) sample of photoelectrically determined rotational parameters for 17 main belt asteroids with diameters less than 30 km are compared with previous observations of asteroids of that size range. Rigorous statistical tests are applied to investigate bias effects and quantify results on asteroid rotation. The samples are described and compared for rotational frequency, rotational amplitude, frequency distribution, and diameter and frequency dependence. It is concluded that the observed rotational frequency distribution can be acceptably fit by two Maxwellian distributions, which is consistent with the hypothesis that there are separate populations of slow and fast rotating asteroids. The frequency distributions of main belt asteroids less than 15 km in diameter and earth and Mars crossers do not differ significantly, but the larger mean lightcurve amplitude of these crossers is statistically significant. No significant diameter dependence on rotational frequency is found among the sample asteroids.

Binzel, R. P.↗
DOE OSTI2024

A new ductile, tougher resin for impregnation of superconducting magnets

A major remaining challenge for Nb 3 Sn high field magnets is their training due to random temperature variations in the coils. The main objective of our research is to reduce or eliminate it by finding novel impregnation materials in replacement of the epoxies currently used. An organic olefin-based thermosetting dicyclopentadiene resin, C 10 H 12 , commercially available in Japan as TELENE® by RIMTEC, was used to impregnate a short Nb 3 Sn undulator coil developed by ANL and FNAL. This magnet reached short sample limit after only two quenches, compared with ∼100 when CTD-101K® was used. Ductility, i.e. the ability to accept large strains, and toughness were identified as key properties to achieve these results. In addition, we have been investigating whether mixing TELENE with high heat capacity ceramic powders such as Gd 2 O 3 , Gd 2 O 2 S, and HoCu 2 , increases the specific heat (C p ) of impregnated Nb3Sn superconducting magnets. The viscosity, heat capacity, thermal conductivity, and other physical properties of TELENE with high-C p powder fillers were measured in this study as a function of temperature and magnetic field. The TELENE-87 wt%Gd 2 O 2 S had a peak in C p between 4.3 K and 5.3 K at fields between 0 and 8 T. We have also investigated the effect on the mechanical properties of pure and mixed TELENE under 10 MGy of gamma ray irradiation at the Takasaki Advanced Radiation Research Institute in Takasaki, Japan. TELENE-87 wt%Gd 2 O 2 S exhibited exceptional radiation resistance. Impregnating an undulator coil with TELENE mixed with Gd 2 O 2 S powder will verify whether the coils' thermal stability further improves, or whether its low diffusivity will require engineering the material with high-thermal conductivity components. Short magnet training will lead to better magnet reliability, lower magnet margins, lower risk and substantial saving in accelerators' commissioning costs. Part of this study is supported by the U.S.-Japan Science and Technology Cooperation Program in high energy physics operated by MEXT in Japan and DOE in the U.S.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2022

Optimizing the shape of photometric redshift distributions with clustering cross-correlations

We present an optimization method for the assignment of photometric galaxies to a chosen set of redshift bins. This is achieved by combining simulated annealing, an optimization algorithm inspired by solid-state physics, with an unsupervised machine learning method, a self-organizing map (SOM) of the observed colours of galaxies. Starting with a sample of galaxies that is divided into redshift bins based on a photometric redshift point estimate, the simulated annealing algorithm repeatedly reassigns SOM-selected subsamples of galaxies, which are close in colour, to alternative redshift bins. We optimize the clustering cross-correlation signal between photometric galaxies and a reference sample of galaxies with well-calibrated redshifts. Depending on the effect on the clustering signal, the reassignment is either accepted or rejected. By dynamically increasing the resolution of the SOM, the algorithm eventually converges to a solution that minimizes the number of mismatched galaxies in each tomographic redshift bin and thus improves the compactness of their corresponding redshift distribution. This method is demonstrated on the synthetic Legacy Survey of Space and Time cosmoDC2 catalogue. We find a significant decrease in the fraction of catastrophic outliers in the redshift distribution in all tomographic bins, most notably in the highest redshift bin with a decrease in the outlier fraction from 57 percent to 16 percent.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1971

Estimation of microwave absorption in the Jupiter atmosphere

A procedure for estimating the microwave absorption loss of the Jupiter atmosphere is presented. Estimation of microwave absorption by planetary atmospheres involves two different investigative disciplines (1) the determination of an acceptable model of the atmosphere itself and (2) the determination of the microwave attenuation rate applicable to each different volume sample of the atmosphere, and the integration of this loss over the varying radio propagation path for any given entry trajectory to obtain the total loss.

Coombs, W. C.↗
NASA NTRS1974

Agriculture, forestry, range resources

In the area of crop specie identification, it has been found that temporal data analysis, preliminary stratification, and unequal probability analysis were several of the factors that contributed to high identification accuracies. Single data set accuracies on fields of greater than 80,000 sq m (20 acres) are in the 70- to 90-percent range; however, with the use of temporal data, accuracies of 95 percent have been reported. Identification accuracy drops off significantly on areas of less than 80,000 sq m (20 acres) as does measurement accuracy. Forest stratification into coniferous and deciduous areas has been accomplished to a 90- to 95-percent accuracy level. Using multistage sampling techniques, the timber volume of a national forest district has been estimated to a confidence level and standard deviation acceptable to the Forest Service at a very favorable cost-benefit time ratio. Range specie/plant community vegetation mapping has been accomplished at various levels of success (69- to 90-percent accuracy). However, several investigators have obtained encouraging initial results in range biomass (forage production) estimation and range readiness predictions. Soil association map correction and soil association mapping in new area appear to have been proven feasible on large areas; however, testing in a complex soil area should be undertaken.

Crea, W. J.↗
NASA NTRS1976

An ad hoc map evaluation procedure

An ad hoc map evaluation procedure is proposed which is most suitable for evaluating low-resolution classification maps against high resolution ground truth maps, such as maps against interpreted aircraft photographs. Commonly practiced sampling and evaluation procedures are impracticable in this context because of difficulties in registration and in comparing the samples. This ad hoc procedure is designed to overcome these two major problems, and its practicability is discussed. Two widely accepted parameters are estimated by the new procedure; namely, the probability of correct classification and the proportion biases. Statistical qualifications are also provided.

Kan, E. P.↗
NASA NTRS1980

Heterodyne signal-to-noise ratios in acoustic mode scattering experiments

The relation between the signal to noise ratio (SNR) obtained in heterodyne detection of radiation scattered from acoustic modes in crystalline solids and the scattered spectral density function is studied. It is shown that in addition to the information provided by the measured frequency shifts and line widths, measurement of the SNR provides a determination of the absolute elasto-optical (Pockel's) constants. Examples are given for cubic crystals, and acceptable SNR values are obtained for scattering from thermally excited phonons at 10.6 microns, with no external perturbation of the sample necessary. The results indicate the special advantages of the method for the study of semiconductors.

Cochran, W. R.↗
NASA NTRS1988

The computation of pi to 29,360,000 decimal digits using Borweins' quartically convergent algorithm

The quartically convergent numerical algorithm developed by Borwein and Borwein (1987) for 1/pi is implemented via a prime-modulus-transform multiprecision technique on the NASA Ames Cray-2 supercomputer to compute the first 2.936 x 10 to the 7th digits of the decimal expansion of pi. The history of pi computations is briefly recalled; the most recent algorithms are characterized; the implementation procedures are described; and samples of the output listing are presented. Statistical analyses show that the present decimal expansion is completely random, with only acceptable numbers of long repeating strings and single-digit runs.

Bailey, David H.↗
DOE OSTI2018

Efficient Computation of Free Energy Surfaces of Diels–Alder Reactions in Explicit Solvent at Ab Initio QM/MM Level

For Diels–Alder (DA) reactions in solution, an accurate and converged free energy (FE) surface at ab initio (ai) quantum mechanical/molecular mechanical (QM/MM) level is imperative for the understanding of reaction mechanism. However, this computation is still far too expensive. In a previous work, we proposed a new method termed MBAR+wTP, with which the computation of the ai FE profile can be accelerated by several orders of magnitude via a three-step procedure: (I) an umbrella sampling (US) using a semi-empirical (SE) QM/MM Hamiltonian is performed; (II) the FE profile is generated using the Multistate Bennett Acceptance Ratio (MBAR) analysis; and (III) a weighted Thermodynamic Perturbation (wTP) from the SE Hamiltonian to the ai Hamiltonian is performed to obtain the ai QM/MM FE profile using weight factors from the MBAR analysis. In this work, this method is extended to the calculations of two-dimensional FE surfaces of two Diels–Alder reactions of cyclopentadiene with either acrylonitrile or 1-4-naphthoquinone at ai QM/MM level. The accurate activation free energies at the ai QM/MM level, which are much closer to the experimental measurements than those calculated by other methods, indicate that this MBAR+wTP method can be applied in the studies of complex reactions in condensed phase with much-enhanced efficiency.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗