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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 685 records · Page 38
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Development of a Nitrogen and Magnesium Oxide based Class A, B & D Suffocating Fire System (SFSS) for Gloveboxes

Testing related to the development and performance of a “Proof of Concept” Nitrogen/Magnesium Oxide Suffocating Fire System (SFSS) was conducted at Fire and Pump Service Group (FPSG) located in Rancho Dominguez, California. The SFSS Engineering Team (SFSSET), consisting of FPSG and Los Alamos National Laboratory (LANL) personnel researched, developed a prototype, and conducted testing to determine effective means to deliver magnesium oxide (MgO) sand into a glovebox (GB) in a class D fire event. The prototypes development also established the effective coverage area of a magnesium oxide suppression system as well as demonstrated that the GB inert atmosphere could be maintained during and after the release of the MgO sand to control Class A, B and D fires. Previous testing conducted on nitrogen based SFSS provided evidence that the nitrogen based SFSS controlled Class A and B fires (Ralph Clayton, Los Alamos National Laboratory, Brandon Troc and Frank Broidy, Fire and Pump Service Group 2020).Final testing was conducted within a mock GB capable of simulating an inert glovebox atmosphere. Testing demonstrated that the inert atmosphere can be maintained during and after discharge of the MgO sand over a coverage area.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗
DOE OSTI2021

EMPIRE Simulations of the July 2020 photoelectron driven cavity B-Dot experiments at the National Ignition Facility

Simulations of several of the end-irradiated cylindrical photoelectron driven cavity experiments (also known as B-Dot cavities) that were fielded during the July 1 through 2, 2020 shot series at the National Ignition Facility are presented in this report with comparisons to experimental measurements. All cavity B-Dots fielded on the second, third, fourth, fifth and seventh shots were simulated using coupled Integrated Tiger Series (ITS) Monte Carlo transport codes and the Electromagnetic Plasmas in Realistic Environments (EMPIRE) electromagnetic particle-in-cell code.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2023

Synthesis of Hf 0.75 Ta 0.25 B 2 for self-coating TPS

Ultra-high temperature ceramic materials (UHTCs) are important for designing high-performance aerospace vehicles that can withstand repeated exposures to high temperatures. UHTCs mixed with silicides often have well-controlled oxidation due to the formation of protective silicates, which create a regenerative outer protective layer. Borides are known to have high melting points, high hardness and reasonably good oxidation resistance. In this study, Hf 0.75 Ta 0.25 B 2 (HTB) is proposed as a potential alternative to YSZ protective coatings and ZrB 2- SiC composites via the formation of Hf 6 Ta 2 O 17 (HTO) passivation layer. The objective of this paper is to explore the parameter space of HTB synthesis via borocarbothermal (BCTR). Effects on particle size, phase purity, and residual oxygen content were analyzed with parameters of atmosphere composition, reactant grain sizes, and differing reaction pathways. The BCTR of HfO 2 and Ta 2 O 5 were analyzed to predict HTB behavior. It was shown that both one-step and two-step reaction routes can yield HTB, but two-step yields a purer product. Nano B 4 C produced finer HTB and facilitated reaction completion. Using a reducing atmosphere also enhanced reaction completion

36 MATERIALS SCIENCE↗
DOE OSTI2023

Transversely Polarized Solid Target for Hall B at Jefferson Lab

The physics program for Hall B at Jefferson Lab includes multiple, high-impact experiments scattering electrons from transversely polarized protons. These experiments will measure, for example, the Transverse Momentum Distributions and the Generalized Parton Distribution for protons, using, respectively, semi-inclusive deep inelastic scattering and deeply virtual Compton scattering. In this talk I will discuss the technical challenges to implementing a polarized solid-state target in the Hall B experimental environment, examine potential solutions, and describe the current status of the target design.

Keith, Christopher↗
DOE OSTI2025

Optimizing Adhesion: Evaluating B-Stage Epoxy for Bonding [Poster]

The application of increased pressure during the curing process of B-stage epoxy has been hypothesized to enhance the adhesive properties and bond strength in printed wiring board (PWB) assembly. This study aimed to investigate the correlation between pressure application and the performance of B-stage epoxy.

42 ENGINEERING↗
DOE OSTI2023

Fast and Thermal Neutron Spectrum Dosimetry Measurements in the Advanced Test Reactor large-B and small-I Positions Following the Sixth Core Internals Change-out [Slides]

The Advanced Test Reactor (ATR) has a wide variety of irradiation positions that have had experiments that were developed by users from around the world. Most experiment irradiations rely on thoroughly benchmarked numerical models. However, some irradiation positions in ATR are not as well- characterized and are complicated by spectral perturbations from control cylinder orientation. The “small I” and “large-B” irradiation positions are located nearby control cylinders and suffer from these flux perturbations from control cylinder orientations that change during an irradiation cycle to maintain the desired core power distribution. Models predicted that these types of position would exhibit both spectral shifts and amplitude changes in neutron flux, but few measurements have been conducted to benchmark these predictions. Recently, requalification testing was performed to confirm the operational readiness of the ATR following the completion of the Core Internals Change-out (CIC). These tests provided a unique opportunity to validate the analytical methods used to simulate the ATR because nearly all components in the reactor were in a clean as-built state, significantly reducing modelling uncertainties. One subset of the testing included characterization of the fast and thermal neutron flux in the “small-I” and “large-B” positions using silver, cobalt, and nickel neutron dosimetry. In contrast to typical irradiation cycles, the control cylinders were held in position during the post-CIC nuclear testing. The specific activity of these dosimeter wires was measured following two low-power tests with different control cylinder positions.

21 - SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLAN↗
DOE OSTI2022

UAE6 - Wind Tunnel Tests Data - UAE6 - Sequence B - Raw Data

Sequences B, C, and D: Downwind Baseline (F), Downwind Low Pitch (F), Downwind High Pitch (F) This test sequence used a downwind, teetered turbine with a 3.4° cone angle. The wind speed ranged from 5 m/s to 25 m/s. Yaw angles of ±180° were achieved at low wind speeds, and yaw angles of -20° to 10° were achieved for high wind speeds. The blade tip pitch was 3° for sequence B, 0° for sequence C, and 6° for sequence D. These three sequences were interleaved during testing because the pitch angle change was easily made by the turbine operator. The rotor rotated at 72 RPM. Blade and probe pressure measurements were collected.

17 WIND ENERGY↗
DOE OSTI2025

TTP - WREF 3D Sonic Anemometer Tower B / Raw Data

Tower B is one of four subcanopy towers that were installed in the WREF canopy across a transect distance of 200m. Tower B had two CSAT3-3D sonics mounted at a height of 2.7 m a.g.l. One (B1) is facing 270 degrees; the second (B2) is facing 90 degrees. The towers were installed to observe flow just above the forest floor and to identify any advection flows in the canopy. These data were also part of a larger ICOS project looking at forest flow coupling/decoupling with tower sites in Italy and Czech Republic.

17 WIND ENERGY↗
DOE OSTI2023

$B$-meson semileptonic decays with highly improved staggered quarks

We present an update of the Fermilab Lattice and MILC Collaborations project to compute the form factors for semileptonic $B_{(s)}$-meson decays. Our calculation uses the highly improved staggered quark (HISQ) action for sea and valence quarks, and ensembles with up, down, strange, and charm quarks in the sea. Using a highly improved action with the MILC Collaboration's gauge ensembles with lattice spacings down to $a\approx0.03$ fm, allows the heavy valence quarks to be treated with the same discretization as the light and strange quarks. This unified treatment of the valence quarks allows for absolutely normalized vector currents, bypassing the need for perturbative matching, which has been a source of uncertainty in previous calculations of $B$-meson decay form factors by our collaboration. All preliminary form-factor results are blinded.

Lytle, Andrew↗
DOE OSTI2020

Diagnostic Methodologies of Laser-Initiated 11 B(p,α)2α Fusion Reactions

The detection of the ionic products of low-rate fusion reactions, and in particular of the 11 B(p,α)2α, is one of the recognized main problems in experiments where these reactions are initiated by tailored interaction of intense and high-energy lasers with matter. A thorough description of this important issue, with a critical comparison of the diagnostic opportunities, is indeed so far. In this work, we describe the common diagnostic methodologies used for the detection of the alpha particles generated by the 11 B(p,α)2α reaction and, for each, we outline advantages and limitations, with considerations that can also be applied to other low-rate fusion reactions. We show here that, in general, the univocal characterization of the α products coming from this reaction can be achieved by the simultaneous use of several diagnostic tools placed in close proximity.

11B(p,α)2α reactions↗
DOE OSTI2024

Coupling Kinesin Spindle Protein and Aurora B Inhibition with Apoptosis Induction Enhances Oral Cancer Cell Killing

Many proteins regulating mitosis have emerged as targets for cancer therapy, including the kinesin spindle protein (KSP) and Aurora kinase B (AurB). KSP is crucial for proper spindle pole separation during mitosis, while AurB plays roles in chromosome segregation and cytokinesis. Agents targeting KSP and AurB selectively affect dividing cells and have shown significant activity in vitro. However, these drugs, despite advancing to clinical trials, often yield unsatisfactory outcomes as monotherapy, likely due to variable responses driven by cyclin B degradation and apoptosis signal accumulation networks. Accumulated data suggest that combining emerging antimitotics with various cytostatic drugs can enhance tumor-killing effects compared to monotherapy. Here, we investigated the impact of inhibiting anti-apoptotic signals with the BH3-mimetic Navitoclax in oral cancer cells treated with the selective KSP inhibitor, Ispinesib, or AurB inhibitor, Barasertib, aiming to potentiate cell death. The combination of BH3-mimetics with both KSP and AurB inhibitors synergistically induced substantial cell death, primarily through apoptosis. A mechanistic analysis underlying this synergistic activity, undertaken by live-cell imaging, is presented. Our data underscore the importance of combining BH3-mimetics with antimitotics in clinical trials to maximize their effectiveness.

Silva, João P. N. (ORCID:0000000344554286)↗
DOE OSTI2023

Hardness Measurements and Interface Behavior of SiC-B 4 C-Si Multiple Phase Particulate Composites Made with Melt Infiltration and Additive Manufacturing

Reaction-bonded SiC-B 4 C-Si ceramic composites were binder jet 3D-printed and subsequently pressureless-melt-infiltrated with molten Si. The addition of B 4 C aided the Si infiltration to produce a highly dense composite. The microstructures and phases of these composites were examined. The measured hardness values of each constituent with Vickers and nanoindentation matched the bulk values, and the macro-hardness values with Knoop and spherical indentation represented the bulk, composite hardness values of all three phases together, which was close to a rule of mixtures value. For particulate-based composites, this is a significant finding. The interfacial bonds of SiC and Si were imaged using scanning transmission electron microscopy to view intimacy, whereas the crack propagation was examined with carefully placed indents. This work demonstrated that pressureless melt infiltration with a reactive particle provides a method to shape non-wetting reaction-bonded ceramic composites with limited shrinkage and high density and provides insights into the mechanical behavior with numerous indentation techniques.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Isolation, Structural Analysis and Biological Activity Assays of Biselisabethoxanes A and B: Two Dissymmetric Bis-Diterpenes from the Southwestern Caribbean Sea Gorgonian Coral Pseudopterogorgia elisabethae

Two novel dissymmetric diterpenoids, biselisabethoxanes A and B (1 and 2), were isolated from the hexane extracts of the gorgonian coral Pseudopterogorgia elisabethae. Biselisabethoxane A (1) represents the first example of a marine-derived C40 dimer made of two distinct diterpene fragments, whereas biselisabethoxane B (2) is a fused heterodimer stemming from coupling of two amphilectane-based fragments. The structures of 1 and 2 were elucidated based on 1D and 2D NMR spectral data analysis. The molecular structure of 1 was subsequently confirmed by X-ray crystallographic analysis. When evaluated for their inhibitory effects in a series of well-established biological activity assays the isolated compounds were shown to moderately inhibit the growth of Mycobacterium tuberculosis.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

Kepler-1661 b: A Neptune-sized Kepler Transiting Circumbinary Planet around a Grazing Eclipsing Binary

We report the discovery of a Neptune-sized (R{sub p}=3.87±0.06R{sub ⊕}) transiting circumbinary planet, Kepler-1661 b, found in the Kepler photometry. The planet has a period of ∼175 days and its orbit precesses with a period of only 35 yr. The precession causes the alignment of the orbital planes to vary, and the planet is in a transiting configuration only ∼7% of the time as seen from Earth. As with several other Kepler circumbinary planets, Kepler-1661 b orbits close to the stability radius, and is near the (hot) edge of the habitable zone. The planet orbits a single-lined, grazing eclipsing binary, containing a 0.84 M{sub ⊙} and 0.26 M{sub ⊙} pair of stars in a mildly eccentric (e = 0.11), 28.2 day orbit. The system is fairly young, with an estimated age of ∼1–3 Gyr, and exhibits significant starspot modulations. The grazing eclipse configuration means the system is very sensitive to changes in the binary inclination, which manifests itself as a change in the eclipse depth. The starspots contaminate the eclipse photometry, but not in the usual way of inducing spurious eclipse timing variations. Rather, the starspots alter the normalization of the light curve, and hence the eclipse depths. This can lead to spurious eclipse depth variations, which are then incorrectly ascribed to binary orbital precession.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2020

TOI-1235 b: A Keystone Super-Earth for Testing Radius Valley Emergence Models around Early M Dwarfs

Small planets on close-in orbits tend to exhibit envelope mass fractions of either effectively zero or up to a few percent depending on their size and orbital period. Models of thermally driven atmospheric mass loss and of terrestrial planet formation in a gas-poor environment make distinct predictions regarding the location of this rocky/nonrocky transition in period–radius space. Here we present the confirmation of TOI-1235 b (P = 3.44 days, r{sub p}=1.738{sub −0.076}{sup +0.087} R{sub ⊕}), a planet whose size and period are intermediate between the competing model predictions, thus making the system an important test case for emergence models of the rocky/nonrocky transition around early M dwarfs (R {sub s} = 0.630 ± 0.015 R{sub ⊙}, M {sub s} = 0.640 ± 0.016 M{sub ⊙}). We confirm the TESS planet discovery using reconnaissance spectroscopy, ground-based photometry, high-resolution imaging, and a set of 38 precise radial velocities (RVs) from HARPS-N and HIRES. We measure a planet mass of 6.91{sub −0.85}{sup +0.75} M{sub ⊕}, which implies an iron core mass fraction of 20{sub −12}{sup +15}% in the absence of a gaseous envelope. The bulk composition of TOI-1235 b is therefore consistent with being Earth-like, and we constrain an H/He envelope mass fraction to be <0.5% at 90% confidence. Our results are consistent with model predictions from thermally driven atmospheric mass loss but not with gas-poor formation, suggesting that the former class of processes remains efficient at sculpting close-in planets around early M dwarfs. Our RV analysis also reveals a strong periodicity close to the first harmonic of the photometrically determined stellar rotation period that we treat as stellar activity, despite other lines of evidence favoring a planetary origin (P=21.8{sub −0.8}{sup +0.9} days, m{sub p}sin i=13.0{sub −5.3}{sup +3.8} M{sub ⊕}) that cannot be firmly ruled out by our data.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2020

ARES. III. Unveiling the Two Faces of KELT-7 b with HST WFC3

We present the analysis of the hot-Jupiter KELT-7 b using transmission and emission spectroscopy from the Hubble Space Telescope, both taken with the Wide Field Camera 3. Our study uncovers a rich transmission spectrum that is consistent with a cloud-free atmosphere and suggests the presence of H{sub 2}O and H{sup −}. In contrast, the extracted emission spectrum does not contain strong absorption features and, although it is not consistent with a simple blackbody, it can be explained by a varying temperature–pressure profile, collision induced absorption, and H{sup −}. KELT-7 b had also been studied with other space-based instruments and we explore the effects of introducing these additional data sets. Further observations with Hubble, or the next generation of space-based telescopes, are needed to allow for the optical opacity source in transmission to be confirmed and for molecular features to be disentangled in emission.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2020

TOI-824 b: A New Planet on the Lower Edge of the Hot Neptune Desert

We report the detection of a transiting hot Neptune exoplanet orbiting TOI-824 (SCR J1448-5735), a nearby (d = 64 pc) K4V star, using data from the Transiting Exoplanet Survey Satellite. The newly discovered planet has a radius R {sub p} = 2.93 ± 0.20 R{sub ⊕} and an orbital period of 1.393 days. Radial velocity measurements using the Planet Finder Spectrograph and the High Accuracy Radial velocity Planet Searcher spectrograph confirm the existence of the planet, and we estimate its mass to be 18.47 ± 1.84 M{sub ⊕}. The planet’s mean density is ρ{sub p} = 4.03{sub −0.78}{sup +0.98} g cm{sup −3}, making it more than twice as dense as Neptune. TOI-824 b's high equilibrium temperature makes the planet likely to have a cloud-free atmosphere, and thus it is an excellent candidate for follow-up atmospheric studies. The detectability of TOI-824 b’s atmosphere from both ground and space is promising and could lead to the detailed characterization of the most irradiated small planet at the edge of the hot Neptune desert that has retained its atmosphere to date.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2020

WASP-117 b: An Eccentric Hot Saturn as a Future Complex Chemistry Laboratory

We present spectral analysis of the transiting Saturn-mass planet WASP-117 b, observed with the G141 grism of the Hubble Space Telescope's (HST) Wide Field Camera 3. We reduce and fit the extracted spectrum from the raw transmission data using the open-source software Iraclis before performing a fully Bayesian retrieval using the publicly available analysis suite TauREx 3.0. We detect water vapor alongside a layer of fully opaque cloud, retrieving a terminator temperature of T{sub term}=833{sub -156}{sup +260} K. In order to quantify the statistical significance of this detection, we employ the atmospheric detectability index (ADI), deriving a value of ADI = 2.30, which provides positive but not strong evidence against the flat-line model. Due to the eccentric orbit of WASP-117 b, it is likely that chemical and mixing timescales oscillate throughout orbit due to the changing temperature, possibly allowing warmer chemistry to remain visible as the planet begins transit, despite the proximity of its point of ingress to apastron. We present simulated spectra of the planet as would be observed by the future space missions such as the Atmospheric Remote-sensing Infrared Exoplanet Large-survey and the James Webb Space Telescope and show that, despite not being able to probe such chemistry with current HST data, these observatories should make it possible in the not too distant future.

79 ASTRONOMY AND ASTROPHYSICS↗