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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 613 records · Page 34
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Temporal stability of blue phosphorescent organic light-emitting diodes affected by thermal annealing of emitting layers

Emitting layers were thermally annealed at 20 to 100 °C for varying durations without causing phase transformation in the rest of the PhOLEDs. Heating EMLs above their T g s with a free surface created pinholes filled by the underlying TAPC melt with concurrent interlayer mixing to emit satellite peaks accompanying FIrpic's phosphorescence. With a robust glassy TmPyPB layer on top of the EML, pinholes and fortuitous fluorescence could be prevented. Annealing of mCP:SiPh4:FIrpic induced crystallization in 1 h, while mCP-$\mathscr{L}$-PhSiPh3:FIrpic consistently resisted crystallization under all conditions. Crystallization or pinhole formation diminished EQE and driving voltage at the same time. Without incurring pinhole formation in the absence of a free surface presented by the EML, annealing of mCP:SiPh4:FIrpic at 60 °C for 1 h led to about 50% loss in EQE. In contrast, the pristine device's EQE persisted with mCP-$\mathscr{L}$-PhSiPh3:FIrpic annealed at 60 °C for up to 24 h, beyond which other sources of device failure took over. The concept of bipolar hybrids holds promise for mitigating morphological instability as part of the challenge to the PhOLED device lifetime.

36 MATERIALS SCIENCE↗
NASA NTRS1980

1.0 millimeter maps and radial density distributions of Southern H II/molecular cloud complexes

Measurements of the 1.0-mm continuum emission from seven Southern Hemisphere H II region/molecular cloud complexes located in the inner part of the Galaxy near the galactic plane are presented. The sources were mapped based on observations made by a remote-controlled prime focus infrared photometer on the Cerro Tololo 4-m telescope at a resolution of 65 arcsec. The morphologies and physical characteristics of the sources investigated are found to be similar, with dust column densities of 0.006-0.030 g/sq cm, linear extents of 1.5-3 pc, total masses of 20,000-100,000 solar masses and infrared luminosities between 2 and 4 x 10 to the 6th solar luminosities. In all cases, the dense, extended dust envelopes are observed to be singly peaked and centered about one or more compact near-infrared sources, with a radial density distribution around the central peak proportional to the -1.5 power of the radius as in other extended 1.0-mm continuum sources.

Cheung, L. H.↗
DOE OSTI2014

Study of interstellar molecular clouds using formaldehyde absorption toward extragalactic radio sources

We present new Very Large Array 6 cm H{sub 2}CO observations toward four extragalactic radio continuum sources (B0212+735, 3C 111, NRAO 150, and BL Lac) to explore the structure of foreground Galactic clouds as revealed by absorption variability. This project adds a new epoch in the monitoring observations of the sources reported by Marscher and collaborators in the mid-1990s. Our new observations confirm the monotonic increase in H{sub 2}CO absorption strength toward NRAO 150. We do not detect significant variability of our 2009 spectra with respect to the 1994 spectra of 3C111, B0212+735, and BL Lac; however, we find significant variability of the 3C111 2009 spectrum with respect to archive observations conducted in 1991 and 1992. Our analysis supports that changes in absorption lines could be caused by chemical and/or geometrical gradients in the foreground clouds and not necessarily by small-scale (∼10 AU) high-density molecular clumps within the clouds.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS2002

Modeling Aerodynamically Generated Sound of Helicopter Rotors

A great deal of progress has been made in the modeling of aerodynamically generated sound of rotors over the past decade. Although the modeling effort has focused on helicopter main rotors, the theory is generally valid for a wide range of rotor configurations. The Ffowcs Williams Hawkings (FW-H) equation has been the foundation for much of the development. The monopole and dipole source terms of the FW-H equation account for the thickness and loading noise, respectively. Bladevortex-interaction noise and broadband noise are important types of loading noise, hence much research has been directed toward the accurate modeling of these noise mechanisms. Both subsonic and supersonic quadrupole noise formulations have been developed for the prediction of high-speed impulsive noise. In an effort to eliminate the need to compute the quadrupole contribution, the FW-H equation has also been utilized on permeable surfaces surrounding all physical noise sources. Comparisons of the Kirchhoff formulation for moving surfaces with the FW-H equation have shown that the Kirchhoff formulation for moving surfaces can give erroneous results for aeroacoustic problems. Finally, significant progress has been made incorporating the rotor noise models into full vehicle noise prediction tools.

Brentner, Kenneth S.↗
DOE OSTI2012

EXPANDED SEARCH FOR z {approx} 10 GALAXIES FROM HUDF09, ERS, AND CANDELS DATA: EVIDENCE FOR ACCELERATED EVOLUTION AT z > 8?

We search for z {approx} 10 galaxies over {approx}160 arcmin{sup 2} of Wide-Field Camera 3 (WFC3)/IR data in the Chandra Deep Field South, using the public HUDF09, Early Release Science, and CANDELS surveys, that reach to 5{sigma} depths ranging from 26.9 to 29.4 in H{sub 160} AB mag. z {approx}> 9.5 galaxy candidates are identified via J{sub 125} - H{sub 160} > 1.2 colors and non-detections in any band blueward of J{sub 125}. Spitzer Infrared Array Camera (IRAC) photometry is key for separating the genuine high-z candidates from intermediate-redshift (z {approx} 2-4) galaxies with evolved or heavily dust obscured stellar populations. After removing 16 sources of intermediate brightness (H{sub 160} {approx} 24-26 mag) with strong IRAC detections, we only find one plausible z {approx} 10 galaxy candidate in the whole data set, previously reported in Bouwens et al.. The newer data cover a 3 Multiplication-Sign larger area and provide much stronger constraints on the evolution of the UV luminosity function (LF). If the evolution of the z {approx} 4-8 LFs is extrapolated to z {approx} 10, six z {approx} 10 galaxies are expected in our data. The detection of only one source suggests that the UV LF evolves at an accelerated rate before z {approx} 8. The luminosity density is found to increase by more than an order of magnitude in only 170 Myr from z {approx} 10 to z {approx} 8. This increase is {>=}4 Multiplication-Sign larger than expected from the lower redshift extrapolation of the UV LF. We are thus likely witnessing the first rapid buildup of galaxies in the heart of cosmic reionization. Future deep Hubble Space Telescope WFC3/IR data, reaching to well beyond 29 mag, can enable a more robust quantification of the accelerated evolution around z {approx} 10.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2019

Hydrocarbon Recovery from Williston Basin Shale and Mudrock Cores with Supercritical CO 2 : 2. Mechanisms That Control Oil Recovery Rates and CO 2 Permeation

In part 1 (10.1021/acs.energyfuels.9b01177), CO2 was used to recover oil from 51 source shale and reservoir mudrock cores collected from the Bakken Petroleum System in the Williston Basin. Oil hydrocarbon recoveries after 24 hexposures to CO2 at reservoir pressure and temperature were >94% for the reservoir mudrock cores and ranged from a few percent to as much as 80% for the source shales depending on the well location. In part 2, the experimental parameters that control oil recoveries were investigated, and the results show that exposed rock surface areas and CO2 contact times are primary factors controlling oil recovery at reservoir temperature and pressure. Compared to the 11.2 mm diameter rods used in part 1,increasing the surface area by splitting the rods into a stack of 2−3 mm thick “coins” doubled the oil recovery rates from both reservoir and source rocks, while further increasing the surface area using ground and sieved 1−3.4 mm samples at least tripledrecovery rates. In addition, extending the exposure time for the 11.2 mm diameter source shale rods to 96 h yielded nearly complete oil recoveries (as did the 24 h exposures with the 1−3.4 mm samples), indicating that pore spaces in the source shales as well as the more permeable reservoir rocks can be accessed by the CO2 and the associated oil hydrocarbons recovered. Higher CO 2 pressures yielded higher oil recoveries from both the reservoir rocks and source shales regardless of whether the exposure pressure was at or a little below, somewhat above, or substantially above the minimum miscibility pressure (MMP).Laboratory experiments also demonstrated that crude oil recoveries are based primarily on the ability of the CO 2 to penetrate the rock matrix and dissolve the oil hydrocarbons via hydrocarbon vaporization into the CO 2 phase rather than bulk physical processes (e.g., swelling, lowered viscosity, the physical “sweeping” effect) that are important in conventional CO 2 floods. Lighter hydrocarbons (e.g., C7 to C14) were recovered at much faster rates than heavier hydrocarbons (e.g., >C20) from all rock samples and geometries as well as for all CO2 pressures tested, as might be expected because lighter hydrocarbons have both higher diffusion coefficients and higher solubilities in CO 2 than heavier hydrocarbons. Limiting the amount of CO2 had little or no effect on the recovery rates of the lighter hydrocarbons but greatly reduced those of the heavier hydrocarbons. These two observations are consistent with a concentration-gradient-driven diffusion recovery mechanism. Laboratory results suggest that oil recovery in the Bakken play with CO2 will be enhanced by longer soak times, larger exposed rock surface areas, and higher pressures.

Energy & Fuels↗
DOE OSTI2010

NEAR-IR H{sub 2} EMISSION OF PROTOSTARS: PROBING CIRCUMSTELLAR ENVIRONMENTS

We present new observations of near-infrared molecular hydrogen (H{sub 2}) line emission in a sample of 18 Class I and flat-spectrum low-mass protostars, primarily in the Tau-Aur and {rho} Oph dark clouds. The line emission is extended by up to several arcseconds (several hundred AU) for most objects, and there is little night-to-night variation in line strength coincident with the continuum point source. Flux ratios of H{sub 2} v = 2-1 S(1) and v = 1-0 S(1) lines are consistent with this emission arising in jets or winds in many objects. However, most objects have only small offsets (under 10 km s{sup -1}) between their H{sub 2} and photospheric radial velocities. No objects have line ratios which are clearly caused solely by UV excitation, but the H{sub 2} emission of several objects may be caused by UV or X-ray excitation in the presence of circumstellar dust. There are several objects in the sample whose observed velocities and line fluxes suggest quiescent, non-mechanical origins for their molecular hydrogen emissions. Overall, we find the H{sub 2} emission properties of these protostars to be similar to the T Tauri stars studied in previous surveys.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2016

PROPLYDS AROUND A B1 STAR: 42 ORIONIS IN NGC 1977

We present the discovery of seven new proplyds (i.e., sources surrounded by cometary H α emission characteristic of offset ionization fronts (IFs)) in NGC 1977, located about 30′ north of the Orion Nebula Cluster (ONC) at a distance of ∼400 pc. Each of these proplyds is situated at projected distances 0.04–0.27 pc from the B1V star 42 Orionis ( c Ori), which is the main source of UV photons in the region. In all cases the IFs of the proplyds are clearly pointing toward the common ionizing source, 42 Ori, and six of the seven proplyds clearly show tails pointing away from it. These are the first proplyds to be found around a B star, with previously known examples instead being located around O stars, including those in the ONC around θ {sup 1} Ori C. The radii of the offset IFs in our proplyds are between ∼200 and 550 au; two objects also contain clearly resolved central sources that we associate with disks of radii 50–70 au. The estimated strength of the FUV radiation field impinging on the proplyds is around 10–30 times less than that incident on the classic proplyds in the ONC. We show that the observed proplyd sizes are however consistent with recent models for FUV photoevaporation in relatively weak FUV radiation fields.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2015

A LABORATORY STUDY OF C{sub 3}H{sup +} AND THE C{sub 3}H RADICAL IN THREE NEW VIBRATIONALLY EXCITED {sup 2}Σ STATES USING A PIN-HOLE NOZZLE DISCHARGE SOURCE

Rotational lines of the positive molecular ion C{sub 3}H{sup +} and of the neutral C{sub 3}H radical in three new vibrationally excited states with {sup 2}Σ symmetry have been detected in a supersonic molecular beam in the centimeter-wave band. The fundamental rotational line of the ion is quite weak, but is observed with similar intensity in a dc discharge through several different hydrocarbon gases when helium is the buffer gas. Under these conditions, the fractional abundance of C{sub 3}H{sup +} relative to C{sub 3}H is estimated to be of order 10{sup −4}, i.e., toward the lower end of the ratio (10{sup −3}–10{sup −4}) found for protonated ions using the same discharge nozzle. For each new {sup 2}Σ state of the C{sub 3}H radical, spectroscopic constants, including those describing hydrogen hyperfine structure, have been determined to high precision. Lines of one {sup 2}Σ state (B = 11271 MHz) are particularly intense in our molecular beam; for this state and a second one (B = 11306 MHz), millimeter-wave transitions have also been observed between 180 and 340 GHz using a long path dc glow absorption spectrometer. On the basis of intensity measurements with this spectrometer, the inferred rotation–vibration constant α, and theoretical calculations, the state with B = 11271 MHz is tentatively assigned to the ν{sub 5} bending mode, predicted to lie ∼300 cm{sup −1} above ground.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2021

Direct comparison of wire, foil, and hybrid X-pinches on a 200 kA, 150 ns current driver

Wire X-pinches (WXPs) have been studied comprehensively as fast (~1 ns pulse width), small (~1 μm) x-ray sources, created by twisting two or more fine wires into an “X” to produce a localized region of extreme magnetic pressure at the cross-point. Recently, two alternatives to the traditional WXP have arisen: the hybrid X-pinch (HXP), composed of two conical electrodes bridged by a thin wire or capillary, and the laser-cut foil X-pinch (LCXP), cut from a thin foil using a laser. We present a comparison of copper wire, hybrid, and laser-cut foil X-pinches on a single experimental platform: UC San Diego’s ~200 kA, 150 ns rise time GenASIS driver. All configurations produced 1–2 ns pulse width, ≤5 μm soft x-ray (Cu L-shell, ~1 keV) sources (resolutions diagnostically limited) with comparable fluxes. WXP results varied with linear mass and wire count, but consistently showed separate pinch and electron-beam-driven sources. LCXPs produced the brightest (~1 MW), smallest (≤5 μm) Cu K-shell sources, and spectroscopic data showed both H-like Cu K α lines indicative of source temperatures ≥2 keV, and cold K α (~8050 eV) characteristic of electron beam generated sources, which were not separately resolved on other diagnostics (within 1–2 ns and ≤200 μm). HXPs produced minimal K-shell emission and reliably single, bright, and small L-shell sources after modifications to shape the early current pulse through them. Benefits and drawbacks for each configuration are discussed to provide potential X-pinch users with the information required to choose the configuration best suited to their needs.

42 ENGINEERING↗
DOE OSTI2012

NO EVIDENCE FOR A SYSTEMATIC Fe II EMISSION LINE REDSHIFT IN TYPE 1 ACTIVE GALACTIC NUCLEI

We test the recent claim by Hu et al. that Fe II emission in type 1 active galactic nuclei shows a systematic redshift relative to the local source rest frame and broad-line H{beta}. We compile high signal-to-noise median composites using Sloan Digital Sky Survey spectra from both the Hu et al. sample and our own sample of the 469 brightest DR5 spectra. Our composites are generated in bins of FWHM H{beta} and Fe II strength as defined in our 4D Eigenvector 1 formalism. We find no evidence for a systematic Fe II redshift and consistency with previous assumptions that Fe II shift and width (FWHM) follow H{beta} shift and FWHM in virtually all sources. This result is consistent with the hypothesis that Fe II emission (quasi-ubiquitous in type 1 sources) arises from a broad-line region with geometry and kinematics the same as that producing the Balmer lines.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2019

Non Accountable Sealed Radioactive Sources

Presentation describes investigation into defective 10 uCi Cs-137 "button" sources and response to potential contamination, to include radiological control measures, notifications, and awareness reports. Effort involves benchmarking of EFCOG member processes for use and handling of non-accountable sources.

61 RADIATION PROTECTION AND DOSIMETRY↗
DOE OSTI2025

Comparative life cycle assessment of various hydrogen pathways for cleaner methanol synthesis

This study evaluates the potential environmental impacts of e-methanol production using hydrogen from green, yellow, and blue sources, including Gas Switching Reforming for high purity hydrogen production with carbon capture (GSR-H 2 ), and compares their performance across current and renewable energy scenarios. Using a cradle-to-gate life cycle assessment (LCA), the study quantifies impacts across seven TRACI categories. Global warming potential (GWP) ranged from 0.28 kg CO 2 eq/kg MeOH for green hydrogen with renewables to 2.55 kg CO 2 eq/kg MeOH for SMR-CC under grid power. Among the scenarios, renewable electrolysis achieves the lowest GWP, while GSR-H 2 under renewable power offered the best balance of emissions reductions and resource efficiency among the fossil-based routes, offering a viable transitional solution in regions dependent on natural gas infrastructure. The study reveals GSR-H 2 's potential as an alternative to conventional steam methane reforming with carbon capture (SMR-CC), showing its advantages in carbon capture efficiency and reduced life cycle emissions as well as significantly lower water consumption. GSR-H 2 , when powered by renewables, consumed only 1.41 L of water per kg MeOH, an 82% reduction compared to grid-powered electrolysis, highlighting its potential in water-scarce regions. This study is the first to evaluate GSR-H 2 as a hydrogen source for e-methanol, providing new evidence for its role as a cleaner, scalable transitional solution aligned with cleaner production principles.

08 HYDROGEN↗
DOE OSTI2026

Record of Decision: LEBT Energy Change

The LAMP Conceptual Design (LCD), as described in the LAMP Conceptual Design Report incorporates multiple 100-keV low-energy beam transport (LEBT) lines between the ion sources and the radiofrequency quadrupole (RFQ). The LEBT lines transport H + and H - beams from their respective ion sources to the RFQ entrance, and provide the required manipulations (focusing, steering, chopping, etc.) to the ion beams to prepare them for injection into the RFQ and further acceleration.

43 PARTICLE ACCELERATORS↗
NASA NTRS1993

An H chondrite stream - Identification and confirmation

Fall data indicate that a significant, elongate cluster of co-orbital H chondrite falls in May between 1855 and 1895 (H Cluster 1) records encounters with two or three closely spaced and probably related meteoroid stream components, each of which was met near its perihelion. Although meteorites included in the cluster vary widely in petrographic type, shock facies, and Ne-21 exposure age, they have a distinct labile trace element signature that confirms a common thermal history and, thus, a common source region within an H chondrite parent body. Hence, meteorites selected by one criterion (fall parameters) as distinguishable from all other H chondrites, are distinguished from them by another completely different criterion (contents of labile trace elements).

Dodd, Robert T.↗
DOE OSTI2013

THE IONIZED CIRCUMSTELLAR ENVELOPES OF ORION SOURCE I AND THE BECKLIN-NEUGEBAUER OBJECT

The 229 GHz ({lambda}1.3 mm) radio emission from Orion-KL was mapped with up to 0.''14 angular resolution with CARMA, allowing measurements of the flux densities of Source I ({sup S}rcI{sup )} and the Becklin-Neugebauer Object (BN), the two most massive stars in this region. We find integrated flux densities of 310 {+-} 45 mJy for SrcI and 240 {+-} 35 mJy for BN. SrcI is optically thick even at 229 GHz. No trace of the H30{alpha} recombination line is seen in its spectrum, although the v {sub 2} = 1, 5(5,0)-6(4,3) transition of H{sub 2}O, 3450 K above the ground state, is prominent. SrcI is elongated at position angle 140 Degree-Sign , as in 43 GHz images. These results are most easily reconciled with models in which the radio emission from SrcI arises via the H{sup -} free-free opacity in a T < 4500 K disk, as considered by Reid et al. By contrast, the radio spectrum of BN is consistent with p {sup +}/e {sup -} free-free emission from a dense (n{sub e} {approx} 5 Multiplication-Sign 10{sup 7} cm{sup -3}), but otherwise conventional, hypercompact H II region. The source is becoming optically thin at 229 GHz, and the H30{alpha} recombination line, at V {sub LSR} = 23.2 {+-} 0.5 km s{sup -1}, is prominent in its spectrum. A Lyman continuum flux of 5 Multiplication-Sign 10{sup 45} photons s{sup -1}, consistent with that expected from a B star, is required to maintain the ionization. Supplementary 90 GHz observations were made to measure the H41{alpha} and H42{alpha} recombination lines toward BN. Published 43 and 86 GHz data suggest that SrcI brightened with respect to BN over the 15 year period from 1994 to 2009.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2022

Mining Nontraditional Water Sources for a Distributed Hydrogen Economy

Securing decarbonized economies for energy and commodities will require abundant and widely available green H 2 . Ubiquitous wastewaters and nontraditional water sources could potentially feed water electrolyzers to produce this green hydrogen without competing with drinking water sources. Herein, we show that the energy and costs of treating nontraditional water sources such as municipal wastewater, industrial and resource extraction wastewater, and seawater are negligible with respect to those for water electrolysis. We also illustrate that the potential hydrogen energy that could be mined from these sources is vast. Based on these findings, we evaluate the implications of small-scale, distributed water electrolysis using disperse nontraditional water sources. Techno-economic analysis and life cycle analysis reveal that the significant contribution of H 2 transportation to costs and CO 2 emissions results in an optimal levelized cost of hydrogen at small- to moderate-scale water electrolyzer size. The implications of utilizing nontraditional water sources and decentralized or stranded renewable energy for distributed water electrolysis are highlighted for several hydrogen energy storage and chemical feedstock applications. Finally, we discuss challenges and opportunities for mining H 2 from nontraditional water sources to achieve resilient and sustainable economies for water and energy.

54 ENVIRONMENTAL SCIENCES↗