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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
DOE OSTI2020

Prenatal Ultrasound Analysis of Umbilical‐Portal‐Systemic Venous Shunts Concurrent With Trisomy 21

Objectives A classification termed umbilical‐portal‐systemic venous shunt (UPSVS) for an abnormal umbilical vein (UV), portal vein (PV), and ductus venosus (DV) was proposed recently. According to this classification, there are 3 types of UPSVSs: types I, II, and III. Trisomy 21 associated with UV‐PV‐DV anomalies has been described, but the incidence of trisomy 21 in UPSVS cases, the relationship between UPSVS types and trisomy 21, and the pregnancy outcome are poorly documented. This study aimed to address these issues. Methods All UPSVS cases diagnosed at our department from 2016 to 2019 were retrospectively studied. The English literature describing UV‐PV‐DV anomalies and trisomy 21 from 2000 to 2019 was searched, and the retrieved cases were analyzed. Results Four of 20 UPSVS cases identified by us also had trisomy 21, with 2 type I and 2 type II UPSVSs. Ultrasound markers of Down syndrome were observed in all 4 cases that underwent termination of pregnancy (TOP). The literature search retrieved 12 reports including 279 patients, with 29 also having trisomy 21, giving a pooled trisomy 21 incidence rate of 10.4%. Of the 29 cases, 16 had type I, and 9 had type II, whereas UPSVS types in 4 were undeterminable, and 22 cases underwent TOP. Conclusions There is a high incidence of trisomy 21 in UPSVS cases. Trisomy 21 is associated with a type I or II UPSVS. Most cases with the combined defect underwent TOP. These findings may be used to direct prenatal counseling and management of the combined condition.

Dong, Xiangyi↗
DOE OSTI2020

Fallon, NV FORGE well 21-31 Lithology, Mineral, Image Log, and Injection Test data

Attached is 5 datasets collected from Fallon FORGE well 21-31 located in Churchill County, Nevada collected and interpreted between Feburary 2018-January 2020. This submission includes 1) new lithology interpretation derived from petrographic thin sections of sidewall cores taken from well 21-31, 2) X-Ray Diffraction (XRD) interpretation of sidewall cores and cuttings from well 21-31, 3) Hyperspectral (Short-Wave Infrared and Long-Wave Infrared) interpretation of cuttings and sidewall cores from well 21-31, 4) Interpretation of Formation MicroImager (FMI) and Borehole Televiewer (BHTV) image logs for natural fractures and induced structures for well 21-31, 5) Injection test data and associated analytical model parameters from well testing of well 21-31.

15 GEOTHERMAL ENERGY↗
DOE OSTI2025

Observation of three-proton-decaying resonant states in 21 Al

The structure of the proton-unbound nucleus 21 Al has been studied via proton transfer from a 9 Be target to a 20 Mg beam at E/A = 103 MeV. Three resonant states in 21 Al are identified by the invariant-mass reconstruction of 18 Ne + 3p events. The decay-energy spectra for the two subsystems of 21 Al , i.e. 18 Ne+ 1 p and 18 Ne+ 2 p , indicate that the observed resonant state with the lowest energy has decay branches consisting of three sequential steps of one-proton decay. Based on the ab initio and the distorted-wave Born approximation (DWBA) calculations, this resonant state at Ε ⁎ = 6.09(11) MeV likely has a spin-parity of (1/2 + - 7/2 + ). Meanwhile, the possibility that the observed resonant peak represents an admixture of several states cannot be ruled out. The good isospin-symmetry of the low-lying states with d 5/2 , d 3/2 configurations in the 21 Al- 21 O pair and the ab initio calculations indicate weak configuration mixing between the s - and d -orbital components. The systematics of experimental energy differences between the 5/2 + ground state and lowest-lying 3/2 + excited state for isotopes (isotones) of Z(N) = 13 suggest a likely semimagic nature of 21 Al.

21Al↗
NASA NTRSDate not supplied

Extended Duration: The SIRIUS 21 Crew Perspective

The SIRIUS (Scientific International Research In a Unique terrestrial Station) missions represent a collaborative effort between NASA and Russia’s Institute for Biomedical Problems (IBMP) to conduct a series of long duration isolation and confinement spaceflight analog missions. Three missions of 17-day, 4-month, and 8-month duration (SIRIUS 17, 19, and 21) have been completed at IBMP’s Ground-Based Experimental Complex / Nazemnyy eksperimental'nyy kompleks (NEK) in Moscow, Russia. The international SIRIUS 21 crew comprising representatives from the United States, United Arab Emirates and Russia recently completed the 8-month analog lunar mission. The extended duration mission included simulated lunar transit, orbital, and surface operations with corresponding deep space communication delay, during which the crew participated in nearly 70 studies, eight of which were sponsored by NASA’s Human Research Program. The studies examined the effect of isolation and confinement on the behavioral health of research subjects, and investigated medical countermeasures, team performance, crew dynamics, crew autonomy, food system risks, consequences of confinement and associated physiological stressors. SIRIUS 21 crewmembers also participated in operational tasks such as Rover and CubeSat assembly, simulated lunar sample assessment, VR activities, robotic arm training, environmental systems monitoring, exercise, greenhouse maintenance and 3D printing. Communication with Mission Control was limited to 30-minute periods every two hours. Since access to the internet and email was restricted, simulated ground support provided the Crew’s primary source of daily news and mission information. This panel discussion will include presentations from the US SIRIUS 21 crewmembers – William Brown and Ashley Kowalski – about their experience participating in the mission and science. A facilitated question and answer session will follow with attendees encouraged to ask questions and join in discussion with the SIRIUS 21 crewmembers about their experiences. William Brown came to SIRIUS 21 with experience spread across multiple industries, including the military, defense contracting, healthcare consulting, software engineering, and logistics. He has lived in the Middle East, Central Asia, and Russia. A former Boren Scholar, Brown is fluent in Russian. He holds a Master of International Business degree from the University of South Carolina’s Darla Moore School of Business. Prior to that, he earned a bachelor’s degree in Russian language, literature, and culture from the University of South Carolina. There, he also completed additional undergraduate coursework in computer science. Ashley Kowalski is a Project Leader in The Aerospace Corporation’s International Partnerships Department, where she works with, represents, and provides technical support to the the U.S. Space Force Space Systems Command International Affairs (SSC/IA) office. Through her numerous national and international assignments (Russia, China, and Germany), she has worked on topics related to international space systems, national security space systems, civil systems (including human spaceflight and civil launch projects), space policy, satellite industry analysis, and satellite manufacturing start-ups. She is proficient in Russian and German, and fluent in Polish. Kowalski received her Bachelor of Science and Master of Science degrees in mechanical and aerospace engineering from George Washington University in 2011 and 2012, respectively.

S. E. Whiting↗
DOE OSTI2025

Field-level reconstruction from foreground-contaminated 21-cm maps

Current and upcoming 21-cm experiments will soon be able to map 21-cm spatial fluctuations in three dimensions for a wide range of redshifts. However, bright foreground contamination and the nature of radio interferometry create significant challenges, making it difficult to access rich cosmological information from the Fourier modes that lie within the “foreground wedge”. Here, in this work, we introduce two approaches aiming to reconstruct the full 21-cm density field, including the missing modes in the wedge: (a) a field-level inference under an effective field theory (EFT) framework; (b) a diffusion-based deep generative model trained on simulations. Under the EFT framework, we implement a fully differentiable forward model that maps the initial conditions of matter fluctuations to the observed, foreground-filtered 21-cm maps. This enables a gradient-based sampler to simultaneously sample the initial conditions and bias parameters, allowing a physically motivated mode reconstruction. Alternatively, we apply a variational diffusion model to perform 21-cm density reconstruction at the map level. Our model is trained on semi-numerical simulations over a wide range of astrophysical parameters. Our results from both approaches should provide improved cosmological constraints from the field level and also enable cross-correlation between experiments that have little or no overlapping modes.

cosmological perturbation theory↗
DOE OSTI2022

Constraints on key O 17 ( α , γ ) Ne 21 resonances and impact on the weak s process

The efficiency of the slow neutron-capture process in massive stars is strongly influenced by neutron-capture reactions on light elements. At low metallicity, 16 O is an important neutron absorber, but the effectiveness of 16 O as a light-element neutron poison is modified by competition between subsequent 17 O(α,n) 20 Ne and 17 O(α,γ) 21 Ne reactions. The strengths of key 17 O(α,γ) 21 Ne resonances within the Gamow window for core helium burning in massive stars are not well constrained by experiment. This work presents more precise measurements of resonances in the energy range E c.m. = 612–1319 keV. We extract resonance strengths of ωγ 638 = 4.85 ± 0.79 μeV, ωγ 721 =13.1$^{+3.2}_{-2.4}$ μeV, ωγ 814 = 7.72 ± 0.55 meV, and ωγ 1318 = 136 ±13 meV, for resonances at E c.m. = 638, 721, 814, and 1318 keV, respectively. We also report an upper limit for the 612 keV resonance of ωγ < 140 neV (95% c.l.), which effectively rules out any significant contribution from this resonance to the reaction rate. From this work, a new 17 O(α,γ) 21 Ne thermonuclear reaction rate is calculated and compared to the literature. The effect of present uncertainties in the 17 O(α,γ) 21 Ne reaction rate on weak s-process yields are then explored using postprocessing calculations based on a rotating 20M ⊙ low-metallicity massive star. The resulting 17 O(α,γ) 21 Ne reaction rate is lower with respect to the preexisting literature and found to enhance weak s-process yields in rotating massive star models.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2024

Ne 21 energy levels approaching the α -particle threshold

Nuclei around Ne 20 exhibit an interplay of different excitations caused by different aspects of nuclear structure, including single-particle and multiparticle configurations and collective rotations. One-nucleon transfer reactions selectively probe single-particle structures in these nuclei. These nuclei are also important to astrophysics, with a number of important reactions proceeding through this mass region. Energy levels approaching the α -particle threshold in Ne 21 are of importance to nuclear structure. The Ne 20 ( d , p ) Ne 21 reaction was measured and the corresponding spectroscopic nuclear information was extracted. States in Ne 21 were populated using the Ne 20 ( d , p ) Ne 21 reaction in forward kinematics. Protons were identified in the Triangle Universities Nuclear Laboratory (TUNL) Enge split-pole spectrograph and angular distributions were extracted. Spin-party assignments were made and neutron partial widths were determined based on distorted-wave Born approximation (DWBA) analysis. Several new energy levels were observed at energies of 7176, 7235, 7250, and 7337 keV, and spin-parities are reported which generally agree with previous results where literature was available. Spin and parity assignments are reported for several energy levels along with estimated neutron widths for those states above the neutron threshold ( S n = 6761 keV ). Results from this study are placed in context with a review of the available literature on all known states in this energy region of Ne 21 . Published by the American Physical Society 2024

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2022

Effective bias expansion for 21-cm cosmology in redshift space

A near-future detection of the 21-cm signal from the epoch of reionization will provide unique opportunities to probe the underlying cosmology, provided that such cosmological information can be extracted with precision. To this end, we further develop effective field theory (EFT) inspired techniques for the 21-cm brightness temperature field during the epoch of reionization, incorporating renormalized bias and a treatment of redshift space distortions. Notably, we confirm that in redshift space, measures of the 21-cm brightness, e.g., the power spectrum, should have irreducible contributions that lack a bias coefficient and therefore contain direct, astrophysics-free information about the cosmological density field; in this work, we study this effect beyond linear order. To validate our theoretical treatment, we fit the predicted EFT Fourier-space shapes to the thesan suite of hydrodynamical simulations of reionization at the field level, where the considerable number of modes prevents overfitting. We find agreement at the level of a few percent between the 21-cm power spectrum from the EFT fits and simulations over the wave number range k ≲ 0.8 h/Mpc and neutral fraction x HI ≳ 0.4, which is imminently measurable by the Hydrogen Epoch of Reionization Array and future experiments. Furthermore, the ability of the EFT to describe the 21-cm signal extends to simulations that have different astrophysical prescriptions for reionization as well as simulations with interacting dark matter.

79 ASTRONOMY AND ASTROPHYSICS↗