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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 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1985

Effect of five lubricants on life of AISI 9310 spur gears

Spur-gear surface fatigue tests were conducted with five lubricants using a single lot of consumable-electrode vacuum melted (CVM) AISI 9310 spur gears. The lot of gears was divided into five groups, each of which was tested with a different lubricant. The test lubricants are classified as either a synthetic hydrocarbon, mineral oil, or ester-based lubricant. All five lubricants have imilar viscosity and pressure-viscosity coefficients. A pentaerythritol base stock without sufficient antiwear additives produced a surface fatigue life pproximately 22 percent that of the same base stock with chlorine and phosphorus type additives. The presence of sulfur type antiwear additives in the lubricant did not appear to affect the surface fatigue life of the gears tested. No statistical difference in the 10-percent surface fatigue life was produced with four of the five lubricants.

Townsend, D. P.↗
NASA NTRS1994

Uncertainty of Five-Hole Probe Measurements

A new algorithm for five-hole probe calibration and data reduction using a non-nulling technique was developed, verified, and reported earlier (Wendt and Reichert, 1993). The new algorithm's simplicity permits an analytical treatment of the propagation of uncertainty in five-hole probe measurement. The objectives of the uncertainty analysis are to quantify the uncertainty of five-hole probe results (e.g., total pressure, static pressure, and flow direction) and to determine the dependence of the result uncertainty on the uncertainty of all underlying experimental and calibration measurands. This study outlines a general procedure that other researchers may use to determine five-hole probe result uncertainty and provides guidance for improving the measurement technique.

Reichert, Bruce A.↗
NASA NTRS1999

Five myofibrillar lesion types in eccentrically challenged, unloaded rat adductor longus muscle--a test model

Sarcomere disruptions are observed in the adductor longus (AL) muscles following voluntary reloading of spaceflown and hindlimb suspension unloaded (HSU) rat, which resemble lesions in eccentrically challenged muscle. We devised and tested an eccentric contraction (ECCON) test system for the 14-day HSU rat AL. Six to 7 hours following ECCON, ALs were fixed to allow immunostaining and electron microscopy (EM). Toluidine blue-stained histology semithin sections were screened for lesion density (#/mm2). Serial semithin sections from the ECCON group were characterized for myosin immunointensity of lesions. Five myofibrillar lesion types were identified in histological semithin sections: focal contractions; wide A-bands; opaque areas; missing A-bands; and hyperstretched sarcomeres. Lesion density by type was greater for ECCON than NonECCON ALs (P< or =0.05; focal contractions and opaque regions). Lesion density (#-of-all-five-types/mm2) was significantly different (ECCON: 23.91+/-10.58 vs. NonECCON: 5.48+/-1.28, P< or =0.05; ECCON vs. SHAM: 0.00+/-0.00; P< or = 0.025). PostECCON optimal tension decreased (Poi-drop, 17.84+/-4.22%) and was correlated to lesion density (R2=0.596), but prestretch tension demonstrated the highest correlation with lesion density (R2=0.994). In lesions, the darkly staining A-band lost the normally organized thick filament alignment to differing degrees across the different lesion types. Ranking the five lesion types by a measure of lesion length deformation (hypercontracted to hyperstretched) at the light microscopy level, related to the severity of thick filament registry loss across the lesion types at the electron microscopic level. This ranking suggested that the five lesion types seen in semithin sections at the light level represented a lesion progression sequence and paralleled myosin immunostaining loss as the distorted A-band filaments spread across the hyperlengthening lesion types. Lesion ultrastructure indicated damage involved calcium homeostasis loss (focal contraction lesions) and "thick-filament-centering" failure of titin (wide A-band lesions) in the early stages of lesion development.

NASA Discipline Musculoskeletal↗
NASA NTRSDate not supplied

Construction of an Exact Pressure-Equilibrium Scheme for the Five-Equation Two-Phase Flow Model With Thermal Relaxation

Numerical simulation of compressible multiphase flows based on the four-equation (homogeneous relaxation) model is known to suffer from two fundamental difficulties with (a) wave propagation and (b) pressure equilibrium preservation. First, the mixture sound speed exhibits non-monotonic dependency with respect to the volume fraction, which leads to robustness issues in the resolution of shocks and acoustic wave propagation across two-phase regions. This difficulty can be mitigated by solving Allaire’s five-equation model augmented with infinitely fast phasic temperature equilibrium, from which solutions of the four-equation model can be recovered. However, when temperature is non-uniform, this augmented five-equation formulation still fails to preserve pressure equilibrium across material interfaces. In this work, we propose a fully conservative numerical scheme that exactly preserves pressure equilibrium at the discrete level for the augmented five-equation model, for arbitrary initial distributions of temperature and volume fraction. Combined with the monotonic sound speed property of the five-equation formulation, the proposed pressure-equilibrium preserving scheme significantly improves robustness in the presence of strong multiphase interactions, including shock–interface interactions and advection of material interfaces.

ESG↗
DOE OSTI2023

The five-point bootstrap

We study five-point correlation functions of scalar operators in d-dimensional conformal field theories. We develop a new approach to computing the five-point conformal blocks for exchanged primary operators of arbitrary spin by introducing a generalization of radial coordinates, using an appropriate ansatz, and perturbatively solving two quadratic Casimir differential equations. We then study five-point correlators 〈σσϵσσ〉 in the critical 3d Ising model. We truncate the operator product expansions (OPEs) in the correlator by including a finite number of primary operators with conformal dimension below a cutoff ∆ ⩽ ∆ cutoff . We then compute several OPE coefficients involving ϵ and two spinning operators by demanding that the truncated correlator approximately satisfies the crossing relation.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2024

Five amino acid mismatches in the zinc-finger domains of Cellulose Synthase 5 and Cellulose Synthase 6 cooperatively modulate their functional properties by controlling homodimerization in Arabidopsis

Cellulose synthase 5 (CESA5) and CESA6 are known to share substantial functional overlap. In the zinc-finger domain (ZN) of CESA5, there are five amino acid (AA) mismatches when compared to CESA6. These mismatches in CESA5 were replaced with their CESA6 counterparts one by one until all were replaced, generating nine engineered CESA5s. Each N-terminal enhanced yellow fluorescent protein-tagged engineered CESA5 was introduced to prc1-1, a cesa6 null mutant, and resulting mutants were subjected to phenotypic analyses. For this work, we found that five single AA-replaced CESA5 proteins partially rescue the prc1-1 mutant phenotypes to different extents. Multi-AA replaced CESA5s further rescued the mutant phenotypes in an additive manner, culminating in full recovery by CESA5 G43R + S49T+S54P+S80A+Y88F . Investigations in cellulose content, cellulose synthase complex (CSC) motility, and cellulose microfibril organization in the same mutants support the results of the phenotypic analyses. Bimolecular fluorescence complementation assays demonstrated that the level of homodimerization in every engineered CESA5 is substantially higher than CESA5. The mean fluorescence intensity of CSCs carrying each engineered CESA5 fluctuates with the degree to which the prc1-1 mutant phenotypes are rescued by introducing a corresponding engineered CESA5. Taken together, these five AA mismatches in the ZNs of CESA5 and CESA6 cooperatively modulate the functional properties of these CESAs by controlling their homodimerization capacity, which in turn imposes proportional changes on the incorporation of these CESAs into CSCs.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

Levelized Cost of CO 2 Captured Using Five Physical Solvents in Pre-combustion Applications

Aspen Plus v8.8 was used to perform techno-economic analysis (TEA) of a CO 2 capture process from a typical fuel gas stream in a 543-MW pre-combustion power plant using five different physical solvents (Selexol, PEGPDMS-1, NMP, [aPy][Tf 2 N] and [hmim][Tf 2 N]). The process included a countercurrent packed-bed absorber operating under high-pressure over a wide range of temperatures and three pressure-swing flash drums for solvent regeneration. Furthermore, two packings, Mellapak 250Y and IMTP50, were used and the Levelized costs of CO 2 captured (LCOC) were calculated. The simulation results indicated that using Mellapak 250Y exhibited lower LCOC values than those when using IMTP50 for the five solvents under all conditions used as it offered better mass transfer. The CO 2 capture process carried out at low temperatures showed lower LCOC values than those at higher temperatures due to the increased CO 2 solubility in the solvents at lower temperatures, requiring smaller absorber diameter and lower solvent circulation rates, which offset the cooling requirements. Comparing the lowest LCOC values for the five solvents, the hydrophobic PEGPDMS-1 solvent was the most promising one compared to the other four solvents, due to its lowest capital and operating costs and noncorrosive, which enabled using less expensive materials for the process equipment.

42 ENGINEERING↗
DOE OSTI2024

Formation of five-membered ring structures via reactions of o -benzyne

The formation of five-membered ring structures is important for the generation of curved and bowl-shaped polycyclic aromatic hydrocarbons (PAHs) under combustion conditions. Here, we report the identification of the indenyl (C 9 H 7 ) radical – the simplest aromatic hydrocarbon radical carrying an adjacent five- and six-membered ring, as the major product of the o-benzyne (o-C 6 H 4 ) reaction with propargyl (C 3 H 3 ). Because real flames exhibit a complex chemistry, elucidation of a specific reaction is very challenging. Instead, we studied the o-C 6 H 4 + C 3 H 3 reaction in a resistively heated microtubular SiC reactor at controlled conditions of 1150 K and a pressure near 10–20 Torr. To this end, the reactants o-benzyne and propargyl were pyrolytically generated from benzoyl chloride and propargyl bromide. We identified the reactants and the indenyl radical isomer-selectively utilizing photoion mass-selected threshold photoelectron spectroscopy (ms-TPES). In conclusion, the experimentally observed predominant formation of indenyl radicals finally confirms the theoretical predictions of Matsugi and Miyoshi [Phys. Chem. Chem. Phys. 14 (2012), 9722–9728] and highlights a versatile route for the formation of five-membered rings and curved PAHs via reactions of o-benzyne that favor the formation of multiring species over aliphatically substituted aromatic species.

Molecular-weight growth↗
DOE OSTI2024

A five-year milestone: reflections on advances and limitations in GeoAI research

The Annual Meeting of the American Association of Geographers (AAG) in 2023 marked a five-year milestone since the first Geospatial Artificial Intelligence (GeoAI) Symposium was held at AAG in 2018. In the past five years, progress has been made while open questions remain. In this context, we organized an AAG panel and invited five panellists to discuss the advances and limitations in GeoAI research. The panellists commended the successes, such as the development of spatially explicit models, the production of large-scale geographic datasets, and the use of GeoAI to address real-world problems. The panellists also shared their thoughts on limitations in current GeoAI research, which were considered as opportunities to engage theories in geography, enhance model explainability, quantify uncertainty, and improve model generalizability. This article summarizes the presentations from the panellists and also provides after-panel thoughts from the organizers. We hope that this article can make these thoughts more accessible to interested readers and help stimulate new ideas for future breakthroughs.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2022

Isomers in Tl 203 and core excitations built on a five-nucleon-hole structure

Isomers with three- and five-nucleon-hole configurations have been established in 203 Tl These include newly identified levels with a three-nucleon-hole structure: I π = (15/2 – ) with T 1/2 = 7.9(5) ns and I π = (35/2 – ) with T 1/2 = 4.0(5) ns. In addition, five-nucleon-hole states have also been established: I π = (39/2 – ) with T 1/2 = 1.9(2) ns and I π = (49/2 + ) with T 1/2 = 3.4(4) ns. The previously determined long-lived decay, T 1/2 = 6.6(3) μs from this work, is associated with isomerism of the I π = (29/2 + ) state. Levels above this long-lived isomer have been identified through a delayed-prompt γ–γ coincidence measurement. Five-nucleon-hole states with excitation energies E x ≈ 7 MeV have been established as well as possible octupole excitations of the 208Pb core built on these levels. Furthermore, the level scheme of 203 Tl is extended up to E x ≈ 11 MeV with the inclusion of 25 new transitions. Empirical and shell-model calculations have been performed to aid in the description of the observed states which are found to be of intrinsic character.

190 ≤ A ≤ 219↗
DOE OSTI2023

Cost and Performance Analysis for Five Existing Geothermal Heat Pump-Based District Energy Systems in the United States

District energy systems supplied by geothermal heat pumps (GHPs) have been deployed across the United States for both heating and cooling end uses. To better understand their performance and potential, the geothermal research team at the National Renewable Energy Laboratory analyzed cost and performance of five existing GHP-based district energy systems in the United States. The five systems selected are Ball State University in Indiana, Colorado Mesa University in Colorado, Miami University in Ohio, West Union in Iowa, and Whisper Valley in Texas. The necessary information, including district size, operation period, GHP performance, and costs, was collected through literature review and interviews. The survey results indicated the five systems studied consist of geothermal borehole field(s) and ground loop(s) connected to central loop. While the GHPs were in central plants at Ball State University and Miami University, the central loops at Colorado Mesa University, West Wood, and Whisper Valley were connected through service lines to individual heat pumps in each building. Our analysis indicates the systems have been operating reliably and cost-effectively and contributed to a reduction in carbon emissions.

15 GEOTHERMAL ENERGY↗
DOE OSTI2020

Insights of Molecular Mechanism of Xylem Development in Five Black Poplar Cultivars

Black poplar (Populus deltoides, P. nigra, and their hybrids) is the main poplar cultivars in China. It offers interesting options of large-scale biomass production for bioenergy due to its rapid growth and high yield. Poplar wood properties were associated with chemical components and physical structures during wood formation. In this study, five poplar cultivars, P. euramericana ‘Zhonglin46’ (Pe1), P. euramericana ‘Guariento’ (Pe2), P. nigra ‘N179’ (Pn1), P. deltoides ‘Danhong’ (Pd1), and P. deltoides ‘Nanyang’ (Pd2), were used to explore the molecular mechanism of xylem development. We analyzed the structural differences of developing xylem in the five cultivars and profiled the transcriptome-wide gene expression patterns through RNA sequencing. The cross sections of the developing xylem showed that the cell wall thickness of developed fiber in Pd1 was thickest and the number of xylem vessels of Pn1 was the least. A total of 10,331 differentially expressed genes were identified among 10 pairwise comparisons of the five cultivars, most of them were related to programmed cell death and secondary cell wall thickening. K-means cluster analysis and Gene Ontology enrichment analysis showed that the genes highly expressed in Pd1 were related to nucleotide decomposition, metabolic process, transferase, and microtubule cytoskeleton; whereas the genes highly expressed in Pn1 were involved in cell wall macromolecule decomposition and polysaccharide binding processes. Based on a weighted gene co-expression network analysis, a large number of candidate regulators for xylem development were identified. And their potential regulatory roles to cell wall biosynthesis genes were validated by a transient overexpression system. This study provides a set of promising candidate regulators for genetic engineering to improve feedstock and enhance biofuel conversion in the bioenergy crop Populus.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2023

Signatures of prescribed fire in the microbial communities of Cornus florida are largely undetectable five months post-fire

Prescribed burn is a management tool that influences the physical structure and composition of forest plant communities and their associated microorganisms. Plant-associated microorganisms aid in host plant disease tolerance and increase nutrient availability. The effects of prescribed burn on microorganisms associated with native ecologically and economically important tree species, such as Cornus florida L. (flowering dogwood), are not well understood, particularly in aboveground plant tissues (e.g., leaf, stem, and bark tissues). The objective of this study was to use 16S rRNA gene and ITS2 region sequencing to evaluate changes in bacterial and fungal communities of five different flowering dogwood-associated niches (soil, roots, bark, stem, and leaves) five months following a prescribed burn treatment. The alpha- and beta-diversity of root bacterial/archaeal communities differed significantly between prescribed burn and unburned control-treated trees. In these bacterial/archaeal root communities, we also detected a significantly higher relative abundance of sequences identified as Acidothermaceae, a family of thermophilic bacteria. No significant differences were detected between prescribed burn-treated and unburned control trees in bulk soils or bark, stem, or leaf tissues. The findings of our study suggest that prescribed burn does not significantly alter the aboveground plant-associated microbial communities of flowering dogwood trees five months following the prescribed burn application. Further studies are required to better understand the short- and long-term effects of prescribed burns on the microbial communities of forest trees.

16S rRNA↗
NASA NTRS1977

Infrared continuum observations of five-minute oscillations

Infrared continuum observations of the sun at wavelengths between 10 and 30 microns show a nonisothermal response of the upper photosphere to compression waves associated with the five-minute oscillations. Observations were made with four broad-band filters with effective transmission wavelengths between 10 and 26 microns and with a 10 arcsec aperture. Further observations at submillimeter wavelengths with a 2-arcmin aperture did not resolve oscillatory fluctuations of five-minute period. Comparisons with velocity-field data of Howard (1976) suggest that the relaxation time of the photosphere exceeds (300/2 pi) seconds at the height of formation of the 26-micron continuum. The photosphere reponds to 3-mHz oscillatory motion with considerably less compression than expected for simple acoustic modes in an adiabatically responsive atmosphere, confirming the evanescent character of the five-minute oscillations.

Lindsey, C. A.↗
NASA NTRS1986

X-ray spectroscopy of five BL Lacertae objects

Five X-ray bright BL Lacertae objects were observed in the energy range 0.6-4.5 keV with the solid state spectrometer (SSS) of the Einstein Observatory. The 14 SSS spectra obtained represent most of the X-ray spectra of BL Lac objects with resolution better than approximately 3. These data do not reveal the presence of large amounts of thermal gas, with upper limits for the equivalent width of individual spectral features typically less that about 100 eV. However, the SSS spectra are the first set of X-ray data to indicate low-energy absorption in excess of that caused by the cold interstellar matter in the Galaxy. Comparison with contemporaneous, lower energy X-ray data implies that this absorption does not arise in cold neutral material, but in hotter, highly ionized material, probably intrinsic to the source. All five BL Lac objects have X-ray continua that are well fitted by power-law models, with power-law energy indices usually greater than about 1. In a few cases, a flattening at higher energies is observed; these and other data suggest that two-component X-ray spectra, steep at low energies and flat at high energies, are a common feature of BL Lac objects. Three of the five sources clearly vary between SSS observations, with time scales ranging from days to years. A historical synopsis of the X-ray spectral data confirms the tendency for BL Lacertae objects to be highly variable in the X-ray band but reveals no correlation between spectral and intensity changes.

Urry, C. M.↗
NASA NTRS1992

Properties of five toughened matrix composite materials

The use of toughened matrix composite materials offers an attractive solution to the problem of poor damage tolerance associated with advanced composite materials. In this study, the unidirectional laminate strengths and moduli, notched (open-hole) and unnotched tension and compression properties of quasi-isotropic laminates, and compression-after-impact strengths of five carbon fiber/toughened matrix composites, IM7/E7T1-2, IM7/X1845, G40-800X/5255-3, IM7/5255-3, and IM7/5260 have been evaluated. The compression-after-impact (CAI) strengths were determined primarily by impacting quasi-isotropic laminates with the NASA Langley air gun. A few CAI tests were also made with a drop-weight impactor. For a given impact energy, compression after impact strengths were determined to be dependent on impactor velocity. Properties and strengths for the five materials tested are compared with NASA data on other toughened matrix materials (IM7/8551-7, IM6/1808I, IM7/F655, and T800/F3900). This investigation found that all five materials were stronger and more impact damage tolerant than more brittle carbon/epoxy composite materials currently used in aircraft structures.

Cano, Roberto J.↗
NASA NTRS2003

Enhanced Large Solid Rocket Motor Understanding Through Performance Margin Testing: RSRM Five-Segment Engineering Test Motor (ETM-3)

The Five-Segment Engineering Test Motor (ETM-3) is an extended length reusable solid rocket motor (RSRM) intended to increase motor performance and internal environments above the current four-segment RSRM flight motor. The principal purpose of ETM-3 is to provide a test article for RSRM component margin testing. As the RSRM and Space Shuttle in general continue to age, replacing obsolete materials becomes an ever-increasing issue. Having a five-segment motor that provides environments in excess of normal opera- tion allows a mechanism to subject replacement materials to a more severe environment than experienced in flight. Additionally, ETM-3 offers a second design data point from which to develop and/or validate analytical models that currently have some level of empiricism associated with them. These enhanced models have the potential to further the understanding of RSRM motor performance and solid rocket motor (SRM) propulsion in general. Furthermore, these data could be leveraged to support a five-segment booster (FSB) development program should the Space Shuttle program choose to pursue this option for abort mode enhancements during the ascent phase. A tertiary goal of ETM-3 is to challenge both the ATK Thiokol Propulsion and NASA MSFC technical personnel through the design and analysis of a large solid rocket motor without the benefit of a well-established performance database such as the RSRM. The end result of this undertaking will be a more competent and experienced workforce for both organizations. Of particular interest are the motor design characteristics and the systems engineering approach used to conduct a complex yet successful large motor static test. These aspects of ETM-3 and more will be summarized.

Huppi, Hal↗
NASA NTRS1978

Five Year Flashlight

An ultra-reliable flashlight, initially developed for rescue signaling and utility use by NASA astronauts and military aircrews, has attracted a broad commercial market. Called the Five Year Light, it has a shelf life at least that long because there is no power drain on the batteries when the flashlight is not in use. The NASA version of the light was developed under contract with Langley Research Center by ACR Electronics, Inc., now known as the Chromalloy Electronics Division of Chromalloy American Corporation, Hollywood, Florida. NASA wanted a light that had long shelf life and assured reliability in case it was needed in an emergency. Reliability was designed into the flashlight by means of a unique switch. Instead of the customary thumb-button, the Five Year Light is turned on by rotating its collar to make contact with the battery terminal; the turning motion wipes away any corrosion that might be present and makes contact virtually certain. The Five Year Light available commercially is a repackaged version of the NASA light. It is sold for car, home, industrial, police, firefighting, recreational and a variety of other uses, and sales have topped two million units.

Source record↗