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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 505 records · Page 28
All sourcesNASA NTRSDOE OSTI
NASA NTRS2001

The First Flight of ATIC: Preliminary Results on Li, Be, B Nuclei

The ATIC (Advanced Thin Ionization Calorimeter) balloon experiment had its first test flight which lasted for 16 days and brought it around Antarctica. The ATIC spectrometer consists of a fully active BGO (Bismuth Germanate) calorimeter, scintillator hodoscopes and a silicon matrix. The silicon matrix consisted of 4480 pixels was used as a charge detector in the experiment. We discuss a possibility of the ATIC to measure individual energy spectra of Li, Be and B.

Zatsepin, V. I.↗
NASA NTRS2002

Absorbing Outflows in AGN

The goal of this program was a comprehensive multiwavelength study of absorption phenomena in active galactic nuclei (AGN). These include a variety of associated absorption systems: X-ray warm absorbers, X-ray cold absorbers. UV absorbers with high ionization lines, MgII absorbers, red quasars and BALQSOs. The aim is to determine the physical conditions in the absorbing outflows, study their inter-relations and their role in AGN. We designed several observing programs to achieve this goal: X-ray spectroscopy, UV spectroscopy, FLAY spectroscopy and X-ray imaging. We were very successful towards achieving the goal over the five year period as shown through following observing programs and papers. Copies of a few papers are attached with this report.

Mathur, Smita↗
NASA NTRS2004

Charged Particle Dose Measurements by the Odyssey/MARIE Instrument in Mars Orbit and Model Calculations

Knowledge of the space radiation environment is crucial both for human space exploration, and robotic space missions. It is likely that human explorers will return to the moon, and then go to Mars within the next thirty years. The radiation environment that they will encounter is a significant obstacle to future exploration, and must be dealt with successfully before longterm human missions outside of the magnetosphere can take place. Shielding technologies and materials must be developed to lower the dose and dose equivalent that human beings will receive on such missions. To begin this development, a fairly complete and accurate understanding of the space environment must be obtained. The major components of the space particle radiation environment that are most hazardous to humans are: galactic cosmic rays (GCR), the particles contained in solar particle events, (SPE), and secondary particles generated in material in the spacecraft itself. The intensity of the GCR varies by roughly a factor of two over the eleven-year solar cycle, inversely with the level of solar activity. These GCR particles are fully stripped nuclei, predominantly protons and helium, but also significant numbers of heavier ions, including carbon, oxygen, and iron. Since the ionization caused by nuclei passing through matter is proportional to the square of its charge (Z=10). The MARIE instrument has been described elsewhere.

Cleghorn, T. F.↗
NASA NTRS2004

High Resolution Spectroscopy of AGN in Outburst: The Gaseous Nuclear Environment and the WIGM

This grant is associated to a successful XMM-A02 proposal to observe blazars in outburst states, to X-ray the intergalactic medium, searching for intervening ionized absorption. The observation was triggered on August 31 2003, on the blazar 1H 0414+009 (2=0.287), when the target was showing a level of activity of about 20 mCrab in the total XTE-ASM band. The observation was performed 1 day later (on September 1, 2003) and lasted for 79 ks (79 % of the requested time). Unfortunately, assuming that the XTE-ASM notification was real, the target had recovered his quiescent level of approx. 0.35 mCrab, when the XMM RGS observed it. This, combined with the lower-than-requested exposure, produced an XMM-RGS spectrum containing only - 40 counts per resolution element in the 24.1 less than lambda(A) less than 30 range, insufficient to detect even the strongest predicted lines from the OVII WHIM. However, we do detect the Local Group WHIM OVII system in the spectrum of this blazar.

Mushotzky, Richard↗
NASA NTRS2008

Dead Zone Accretion Flows in Protostellar Disks

Planets form inside protostellar disks in a dead zone where the electrical resistivity of the gas is too high for magnetic forces to drive turbulence. We show that much of the dead zone nevertheless is active and flows toward the star while smooth, large-scale magnetic fields transfer the orbital angular momentum radially outward. Stellar X-ray and radionuclide ionization sustain a weak coupling of the dead zone gas to the magnetic fields, despite the rapid recombination of free charges on dust grains. Net radial magnetic fields are generated in the magnetorotational turbulence in the electrically conducting top and bottom surface layers of the disk, and reach the midplane by ohmic diffusion. A toroidal component to the fields is produced near the midplane by the orbital shear. The process is similar to the magnetization of the solar tachocline. The result is a laminar, magnetically driven accretion flow in the region where the planets form.

solar system↗
NASA NTRSDate not supplied

Intense Equatorial Electrojet and Counter Electrojet caused by the 15 January 2022 Tonga Volcanic Eruption: Space and Ground-based Observations

Abstract Text: We present space and ground-based multi-instrument observations demonstrating the impact of the 2022 Tonga volcanic eruption on dayside equatorial electrodynamics. A strong counter electrojet (CEJ) was observed by Swarm and ground-based magnetometers on 15 January after the Tonga eruption and during the recovery phase of a moderate geomagnetic storm. Swarm also observed an enhanced equatorial electrojet (EEJ) preceding the CEJ in the previous orbit. The observed EEJ and CEJ exhibited complex spatiotemporal variations. We combine them with the Ionospheric Connection Explorer (ICON) neutral wind measurements to disentangle the potential mechanisms. Our analysis indicates that the geomagnetic storm had minimal impact; instead, a large-scale atmospheric disturbance propagating eastward from the Tonga eruption site was the most likely driver for the observed intensification and directional reversal of the equatorial electrojet. The CEJ was associated with strong eastward zonal winds in the E-region ionosphere, as a direct response to the lower atmosphere forcing. Plain-Language Summary: The Earth's E-region ionosphere (~100-150 km altitude) consists of both ionized and neutral gasses, and the two components are coupled through ion-neutral collisions. The state of this region is closely influenced by neutral atmospheric activities from the lower atmosphere and the variability of the solar drivers. On 15 January 2022, the Tonga volcano had a massive eruption and injected an enormous amount of mass and energy into the atmosphere causing disturbances in the E-region ionosphere or even higher. There was also a moderate geomagnetic storm that started one day before the eruption and ended days after. These conditions offer a unique opportunity to understand the different roles they play in controlling the ionosphere. Coordinated observations including the atmosphere, ionosphere and magnetosphere were made from both space and on the ground during this event. We analyzed the magnetic field and neutral wind data and found that a large-scale atmospheric disturbance generated by the volcano eruption was responsible for the observed directional reversal of the dayside equatorial electric field and electric current.

Guan Le↗
DOE OSTI2025

Unconventional low temperature decomposition of a saturated hydrocarbon over atomically-dispersed titanium-aluminum-boron catalyst

Sonochemically-synthesized atomically-dispersed titanium-aluminum-boron nanopowder (TiAlB NP) exhibits a remarkable low-temperature catalytic activation of aliphatic C-H bonds at 750 K followed by C-C bond activation thus emerging as a potent low-cost alternative to expensive platinum group metals. Here, the model saturated hydrocarbon, exo-tetrahydrodicyclopentadiene (C10H16), undergoes catalytic decomposition on TiAlB NPs in a chemical microreactor to produce 1,3-cyclopentadiene (c-C5H6), cyclopentene (c-C5H8), and molecular hydrogen (H2) as detected in situ via isomer-selective, single-photon ionization time-of-flight mass spectrometry. Extensive electronic structure theory calculations on model clusters of the catalyst decode a unique synergy among the atomic constituents of the catalyst and chemical bonding in this stepwise, retro Diels Alder reaction: Ti, although insensitive to C-H activation in its metallic state, initiates the catalysis via chemisorption of the hydrocarbon, adjacent B centers readily abstract hydrogen atoms and store them during the catalytic cycle, while Al stabilizes the catalyst structure yet providing space for critical docking sites for the departing hydrocarbons.

Biswas, Souvick↗
DOE OSTI2022

The Anisotropic Circumgalactic Medium of Massive Early-type Galaxies

Using measurements of the [O iii], Hα, and [N ii] emission line fluxes originating in the cool (T ~10 4 K) gas that populates the halos of massive early-type galaxies with stellar masses greater than 10 10.4 M ⊙ , we explore the recent conjecture that active galactic nucleus (AGN) activity preferentially removes the circumgalactic medium (CGM) along the polar (minor-axis) direction. We find deficits in the mean emission line flux of [O III] and Hα (65% and 43%, respectively) along the polar versus planar directions, although due to the large uncertainties in these difficult measurements the results are of marginal statistical significance (1.5σ). More robustly (97%–99.9% confidence depending on the statistical test), diagnostic line ratios show stronger AGN ionization signatures along the polar direction at small radii than at other angles or radii. Our results are consistent with the conjecture of an anisotropic CGM in massive early-type galaxies, suggested on independent grounds, that is tied to AGN activity and begin to show the potential of CGM mapping using emission lines.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS2015

Using the FLUKA Monte Carlo Code to Simulate the Interactions of Ionizing Radiation with Matter to Assist and Aid Our Understanding of Ground Based Accelerator Testing, Space Hardware Design, and Secondary Space Radiation Environments

Designing hardware to operate in the space radiation environment is a very difficult and costly activity. Ground based particle accelerators can be used to test for exposure to the radiation environment, one species at a time, however, the actual space environment cannot be duplicated because of the range of energies and isotropic nature of space radiation. The FLUKA Monte Carlo code is an integrated physics package based at CERN that has been under development for the last 40+ years and includes the most up-to-date fundamental physics theory and particle physics data. This work presents an overview of FLUKA and how it has been used in conjunction with ground based radiation testing for NASA and improve our understanding of secondary particle environments resulting from the interaction of space radiation with matter.

Reddell, Brandon↗
NASA NTRS1986

Venus - Dead or alive?

In situ nightside electric field observations from the Pioneer Venus Orbiter have been interpreted as evidence of extensive lightning in the lower atmosphere of Venus. The scenario, including proposed evidence of clustering of lightning over surface highland regions, has encouraged the acceptance of currently active volcanic output as part of several investigations of the dynamics and chemistry of the atmosphere and the geology of the planet. However, the correlation between the 100-hertz electric field events attributed to lightning and nightside ionization troughs resulting from the interaction of the solar wind with the ionosphere indicates that the noise results from locally generated plasma instabilities and not from any behavior of the lower atmosphere. Furthemore, analysis of the spatial distribution of the noise shows that it is not clustered over highland topography, but rather occurs at random throughout the latitude and longitude regions sampled by the orbiter during the first 5 years of operation, from 1978 to 1984. Thus the electric field observations do not identify lightning and do not provide a basis for inferring the presence of currently active volcanic output. In the absence of known evidence to the contrary, it appears that Venus is no longer active.

Taylor, Harry A., Jr.↗
DOE OSTI2020

Rational design, synthesis, and evaluation of uncharged, “smart” bis-oxime antidotes of organophosphate-inhibited human acetylcholinesterase

Organophosphate (OP) intoxications from nerve agent and OP pesticide exposures are managed with pyridinium aldoxime–based therapies whose success rates are currently limited. The pyridinium cation hampers uptake of OPs into the central nervous system (CNS). Furthermore, it frequently binds to aromatic residues of OP-inhibited acetylcholinesterase (AChE) in orientations that are nonproductive for AChE reactivation, and the structural diversity of OPs impedes efficient reactivation. Improvements of OP antidotes need to include much better access of AChE reactivators to the CNS and optimized orientation of the antidotes' nucleophile within the AChE active-center gorge. On the basis of X-ray structures of a CNS-penetrating reactivator, monoxime RS194B, reversibly bound to native and venomous agent X (VX)–inhibited human AChE, here we created seven uncharged acetamido bis-oximes as candidate antidotes. Both oxime groups in these bis-oximes were attached to the same central, saturated heterocyclic core. Diverse protonation of the heterocyclic amines and oxime groups of the bis-oximes resulted in equilibration among up to 16 distinct ionization forms, including uncharged forms capable of diffusing into the CNS and multiple zwitterionic forms optimal for reactivation reactions. Conformationally diverse zwitterions that could act as structural antidote variants significantly improved in vitro reactivation of diverse OP-human AChE conjugates. Oxime group reorientation of one of the bis-oximes, forcing it to point into the active center for reactivation, was confirmed by X-ray structural analysis. Finally, our findings provide detailed structure-activity properties of several CNS-directed, uncharged aliphatic bis-oximes holding promise for use as protonation-dependent, conformationally adaptive, “smart” accelerated antidotes against OP toxicity.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Revealing a Pathway for Low-Temperature Recrystallization in Germanium

Thermally activated annealing in semiconductors faces inherent limitations, such as dopant diffusion. Here, a nonthermal pathway is demonstrated for a complete structural restoration in predamaged germanium via ionization-induced recovery. By combining experiments and modeling, this study reveals that the energy transfer of only 2.4 keV nm −1 from incident ions to target electrons can effectively annihilate pre-existing defects and restore the original crystalline structure at room temperature. Moreover, it is revealed that the irradiation-induced crystalline-to-amorphous (c/a) transformation in Ge is reversible, a phenomenon previously considered unattainable without additional thermal energy imposed during irradiation. For partially damaged Ge, the overall damage fraction decreases exponentially with increasing fluence. Surprisingly, the recovery process in preamorphized Ge starts with defect recovery outside the amorphous layer and a shrinkage of the amorphous thickness. After this initial stage, the remaining damage decreases slowly with increasing fluence, but full restoration of the pristine state is not achieved. These differences in recovery are interpreted in the framework of structural differences in the initial defective layers that affect recovery kinetics. This study provides new insights on reversing the c/a transformation in Ge using highly-ionizing irradiation and has broad implications across materials science, radiation damage mitigation, and fabrication of Ge-based devices.

athermal recovery↗
DOE OSTI2022

On the nature of droplet production in DC glows with a liquid anode: mechanisms and potential applications

The interactions between plasma and liquid solutions give rise to the formation of chemically reactive species useful for many applications, but the mass transport in the interfacial region is usually limited and not fully understood. In this work, we report on the observation and explanation of droplet ejection at the plasma–liquid interface of a one-atmosphere glow discharge with the liquid anode. The impact of droplets emission on plasma properties is also analyzed by spectroscopy. The process, which is an efficient mass and charge transport mechanism, apparently occurs during discharge operation and thus constitutes a feedback vehicle between the discharge and the liquid. Distinctive from the well-known Talyor cone droplets associated with liquid cathodes, the observed droplets originate from the bubbles due to electrolysis and solvated air which does not require strong electric field at liquid surface. Instead, the droplets are ejected by bubble cavity rupture at the plasma–liquid interface and their size, initial speed are strongly dependent on the gravity, inertia and capillarity. Further, the droplets emerge near the plasma attachment and are subsequently vaporized, emitting intense UV and visible light, which originated from excited OH radicals and sodium derived from the liquid electrolyte. Spectroscopy analysis confirmed that the bursting droplets generally reduce the gas temperature while their effects on electron density depend on the composition of the liquid anode. Results also show that droplets from NaCl solution increase the plasma electron density due to the lower ionization potential of sodium. These findings reveal a new mechanism for discharge maintenance and mass transport as well as suggest a simple approach to dispersing plasma-activated liquid into the gas phase and thus enhancing plasma–liquid interaction.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2023

Review of the 1st EUV Light Sources Code Comparison Workshop

We review the results of the 1 st Extreme Ultraviolet (EUV) Light Sources Code Comparison Workshop. The goal of this workshop was to provide a platform for specialists in EUV light source plasma modeling to benchmark and validate their numerical codes using well-defined case studies. Detailed consideration of a plethora of atomic collisional and radiative processes is required for modeling EUV light source plasmas. Eight institutions spanning four countries contributed data to the workshop. Two topics were addressed, namely (i) the atomic kinetics and radiative properties of tin plasmas under EUV-generating conditions and (ii) laser absorption in a fully ionized, one-dimensional hydrogen plasma. In this paper, we summarize the key findings of the workshop and outline plans for future iterations of the code comparison activity.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
NASA NTRS1986

Waves and electric fields associated with the first AMPTE artificial comet

The solar-wind Ba release experiment with the Active Magnetospheric Particle Tracer Explorers is discussed. The explosion of the two Ba-containing canisters produced a rapidly expanding cloud of neutral Ba, which was rapidly ionized by the UV radiation from the sun. A static electric field of about 1-2 mV/m was detected inside the diamagnetic cavity created by the ion cloud. This field is in the same direction as the solar-wind electric field, suggesting that this field may be able to penetrate into the cloud. Electrostatic emissions were observed inside the diamagnetic cavity at the Ba ion plasma frequency.

Gurnett, D. A.↗
NASA NTRS1993

On the origin of the Z-shaped narrow-line region in the Seyfert galaxy NGC 3516

A kinematic study has been carried out of the line-emitting gas in the Seyfert galaxy NGC 3516. The existence of two curved filaments in the central 2.5 kpc of this galaxy, which give Z-shaped appearance to its NLR. A precessing twin-jet model in which the line-emitting material is entrained by a precessing radio jet and kept ionized by the nuclear ionization field can explain the kinematic data of the brightest emission rather well. If this model is valid, this would make NGC 3516 the least luminous known active galaxy with a precessing jet. An alternative scenario assumes that the curved inner filaments represent gas entrained by a radio jet which is deflected by ram pressure from the rotation interstellar medium of the galaxy.

Veilleux, Sylvain↗
NASA NTRS2014

BioSentinel/Mars: Interplanetary Space Radiation Biosensor Experiment in Martian Transit on Mars 2020

Despite significant progress understanding biological radiation effects via terrestrial studies, no terrestrial source duplicates space’s unique radiation environment. Furthermore, no biological experiments have been conducted beyond low Earth orbit since Apollo. Understanding space’s fundamental biological effects requires overcoming these limitations. The BioSentinel 4U payload, under development for flight aboard Exploration Mission-1, measures biological responses to deep space radiation. Traveling to more than 1AU from Earth, BioSentinel/EM-1 will record DNA double-strand breaks (DSBs) repaired using a pathway common to humans and BioSentinel’s bioengineered yeast model organism, responding to as few as one biologically repaired DSB. The BioSentinel/Mars 4U instrument (6-8kg; 5-8W; 0.2-1MB/week) would include eighteen 16-well biosensor fluidic cards, activated biweekly during Mars 2020’s cruise phase, to provide a dose-dependent rate of DSB/repair. The instrument, which includes solid-state sensors for total ionizing dose and linear-energy-transfer spectra, addresses MEPAG SKG-B3 by simultaneously measuring both spectra and biological effects of space radiation. Biological measurements are rendered reliable by independent replicate experiments. The spatio-temporal uniformity of interplanetary galactic cosmic radiation makes BioSentinel/EM1 and BioSentinel/Mars approximate replicates, except for any major differences in solar particle events. Results will be compared to Earth and ISS controls to characterize the radiation/reduced-gravity parameter space by its biological impact.

BioSentinel↗
NASA NTRS2019

A New Class of Changing-look LINERs

We report the discovery of six active galactic nuclei (AGNs) caught "turning on" during the first nine months of the Zwicky Transient Facility (ZTF) survey. The host galaxies were classified as low-ionization nuclear emission-line region galaxies (LINERs) by weak narrow forbidden line emission in their archival SDSS spectra, and detected by ZTF as nuclear transients. In five of the cases, we found via follow-up spectroscopy that they had transformed into broad-line AGNs, reminiscent of the changing-look LINER iPTF16bco. In one case, ZTF18aajupnt/AT2018dyk, follow-up Hubble Space Telescope ultraviolet and ground-based optical spectra revealed the transformation into a narrow-line Seyfert 1 with strong [Fe vii, x, xiv] and He ii λ 4686 coronal lines. Swift monitoring observations of this source reveal bright UV emission that tracks the optical flare, accompanied by a luminous soft X-ray flare that peaks ~60 days later. Spitzer follow-up observations also detect a luminous mid-infrared flare, implying a large covering fraction of dust. Archival light curves of the entire sample from CRTS, ATLAS, and ASAS-SN constrain the onset of the optical nuclear flaring from a prolonged quiescent state. Here we present the systematic selection and follow-up of this new class of changing-look LINERs, compare their properties to previously reported changing-look Seyfert galaxies, and conclude that they are a unique class of transients well-suited to test the uncertain physical processes associated with the LINER accretion state.

Sara Frederick↗