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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 307 records · Page 17
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Wavelength-Selective Reactivity of Iron(III) Halide Salts in Photocatalytic C–H Functionalization

The utility of halogen radicals in hydrocarbon functionalization extends from early examples of photochemical halogenation to recent reports using photoredox catalysis with iridium complexes and simple transition metal salts such as FeCl 3 . The majority of these methods (uncatalyzed and iron-catalyzed) require UV light (λ ≤ 390 nm), and systematic efforts to enable the use of visible light remain valuable. We report the use of a simple Fe(III) salt that enables a C–H to C–C and C–N functionalization under visible light. The reactivity and selectivity profile using different light sources demonstrates wavelength-selective behavior, which was further investigated with deuterium kinetic isotope effect experiments and DFT calculations. These results show that control over the reactive intermediates in this iron-catalyzed reaction can be achieved through proper choice of the wavelength of irradiation.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1992

Picosecond sources for sub-centimeter laser ranging

Some of the tradeoffs involved in selecting a laser source for space-based laser ranging are outlined, and some of the recent developments in the laser field most relevant to space-based lasers for ranging and altimetry are surveyed. Laser pulse width and laser design are discussed. It is argued that, while doubled/tripled ND-host lasers are currently the best choice for laser ranging in two colors, they have the shortcoming that the atmospheric transmission at 355 nm is significantly poorer than it is at longer wavelengths which still have sufficient dispersion for two-color laser ranging. The life requirement appears to demand that laser diode pumping be used for space applications.

Krebs, Danny J.↗
DOE OSTI2017

Eye tracking studies based on attentional-resource effectiveness - 310

In the majority of cases, the primary means of information input to operators in nuclear power plants (NPPs) control rooms is through the visual channel. In this study, eye movement patterns of NPP operators are analyzed with eye tracking data obtained from simulator-based experimental studies. Two eye tracking measures of attentional-resource effectiveness in monitoring and detection tasks in NPPs which had been developed by the authors are introduced and several applications with the two eye tracking measures are discussed for the use of the measures. The underlying principle of the measures is that information sources should be selectively attended according to their importance. One of the two measures is the fixation to importance ratio (FIR), which represents attentional resource (eye fixations) spent on an information source compared to the importance of the information source. The other measure is selective attention effectiveness (SAE), which incorporates the FIRs of all information sources. The FIR represents the effectiveness on an information source, whereas the SAE represents the overall effectiveness on all information sources. Frequency and the duration of eye fixations of an operator on information sources are used as attentional resource. Finally feasible future applications with eye tracking data were discussed in terms of plant systems automation and operator training. (authors)

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
NASA NTRS1972

The association of X-ray sources with bright stars.

Comparison of selected Uhuru X-ray sources with the SAO star catalog, revealing ten stars within the positional error of the X-ray sources where only about two are expected on the basis of chance. Three of these are already under study as optical candidates for X-ray sources. The new results lend confidence to these candidates as being correct and yield candidate stars for seven other X-ray sources. The association of bright stars with X-ray sources is expected on the basis of the model which invokes mass transfer from a massive star to a compact companion.

Gursky, H.↗
DOE OSTI2018

Sensitivity Analysis of Contaminant Transport from Vadose Zone Sources to Groundwater

Remedy selection and implementation in the Central Plateau of the Hanford Site will be facilitated by a technically defensible description of vadose zone sources and their spatial and temporal impacts on groundwater. To this end, a case study approach is used to assess impacts to groundwater associated with uncertainties in source terms and hydraulic and sorption parameters for the B-Complex at Hanford. Several unplanned releases of wastes occurred in the tanks in the B-Complex. Several planned liquid waste discharges also occurred to cribs, trenches, tile fields, and French drains within the B-Complex, creating a significant inventory of contaminants in the vadose zone whose downward migration in the subsurface pose a potential threat to groundwater. Given the uncertainty in multiple source locations, volumes and intensities, and uncertainties in hydraulic and sorption properties, an integrated assessment of their combined effects is needed to guide characterization, support selection of appropriate remedies, and design appropriate monitoring for vadose zone source areas and the underlying aquifer.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2023

Life Cycle Assessment of Innovative Carbon Dioxide Selective Membranes from Low Carbon Emission Sources: A Comparative Study

Carbon capture has been an important topic of the twenty-first century because of the elevating carbon dioxide (CO2) levels in the atmosphere. CO2 in the atmosphere is above 420 parts per million (ppm) as of 2022, 70 ppm higher than 50 years ago. Carbon capture research and development has mostly been centered around higher concentration flue gas streams. For example, flue gas streams from steel and cement industries have been largely ignored due to lower associated CO2 concentrations and higher capture and processing costs. Capture technologies such as solvent-based, adsorption-based, cryogenic distillation, and pressure-swing adsorption are under research, but many suffer from higher costs and life cycle impacts. Membrane-based capture processes are considered cost-effective and environmentally friendly alternatives. Over the past three decades, our research group at Idaho National Laboratory has led the development of several polyphosphazene polymer chemistries and has demonstrated their selectivity for CO2 over nitrogen (N2). Poly[bis((2-methoxyethoxy)ethoxy)phosphazene] (MEEP) has shown the highest selectivity. A comprehensive life cycle assessment (LCA) was performed to determine the life cycle feasibility of the MEEP polymer material compared to other CO2-selective membranes and separation processes. The MEEP-based membrane processes emit at least 42% less equivalent CO2 than Pebax-based membrane processes. Similarly, MEEP-based membrane processes produce 34–72% less CO2 than conventional separation processes. In all studied categories, MEEP-based membranes report lower emissions than Pebax-based membranes and conventional separation processes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2016

γ -soft Ba 146 and the role of nonaxial shapes at N ≈ 90

Low-spin states in the neutron-rich, N = 90 nuclide 146 Ba were populated following β decay of 146 Cs , with the goal of clarifying the development of deformation in barium isotopes through delineation of their nonyrast structures. Fission fragments of 146 Cs were extracted from a 1.7-Ci 252 Cf source and mass selected using the CAlifornium Rare Ion Breeder Upgrade (CARIBU) facility. Low-energy ions were deposited at the center of a box of thin β detectors, surrounded by a highly efficient high-purity Ge array. The new 146 Ba decay scheme now contains 31 excited levels extending up to ~2.5 MeV excitation energy, double what was previously known. These data are compared to predictions from the interacting boson approximation (IBA) model. It appears that the abrupt shape change found at N = 90 in Sm and Gd is much more gradual in Ba and Ce, due to an enhanced role of the γ degree of freedom.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2026

Data for Metabolic Engineering of Nonmodel Yeast Issatchenkia orientalis SD108 for 5-Aminolevulinic Acid Production

Biological production of 5‐aminolevulinic acid (5‐ALA) has received growing attentionover theyears.However, thereis the tradeoff between 5‐ALA biosynthesis and cell growth because the fermentation broth will become acidic due to the production of 5‐ALA. To address this limitation, we engineered an acid‐tolerant yeast, Issatchenkia orientalis SD108, for 5‐ALA production. We first discovered that the cell growth rate of I. orientalis SD108 was boosted by 5‐ALA and its endogenous ALA synthetase (ALAS) showed higher activity than those homologs from other yeasts. The titer of 5‐ALA was improved from 28mg/L to 120‐, 150‐, and 300mg/L, by optimizing plasmid design, overexpressing a transporter, and increasing gene copy number, respectively. After redirecting the metabolic flux using the pyruvate decarboxylase (PDC) knockout strain (SD108ΔPDC) and culturing with urea, we increased the titer of 5‐ALA to 510mg/L, a 13‐fold enhancement, proving the importance of the newly identified IoALAS with higher activity and the strategic selection of nitrogen sources for knockout strains. This study demonstrates the acid‐tolerant I. orientalis SD108ΔPDC has a high potential for 5‐ALA production at a large scale in the future.

Bioproducts↗
DOE OSTI2015

Galaxy cluster scaling relations between Bolocam Sunyaev–Zel’dovich effect and Chandra X-ray measurements

We present scaling relations between the integrated Sunyaev–Zel’dovich effect (SZE) signal, Y{sub SZ}, its X-ray analogue, Y{sub X} ≡ M{sub gas} T{sub X}, and total mass, M{sub tot}, for the 45 galaxy clusters in the Bolocam X-ray SZ (BOXSZ) sample. All parameters are integrated within r{sub 2500}. Y{sub 2500} values are measured using SZE data collected with Bolocam, operating at 140 GHz at the Caltech Submillimeter Observatory. The temperature, T{sub X}, and mass, M{sub gas,2500}, of the intracluster medium are determined using X-ray data collected with Chandra, and M{sub tot} is derived from M{sub gas} assuming a constant gas mass fraction. Our analysis accounts for several potential sources of bias, including selection effects, contamination from radio point sources, and the loss of SZE signal due to noise filtering and beam-smoothing effects. We measure the Y{sub 2500}–Y{sub X} scaling to have a power-law index of 0.84 ± 0.07, and a fractional intrinsic scatter in Y{sub 2500} of (21±7)% at fixed Y{sub X}, both of which are consistent with previous analyses. We also measure the scaling between Y{sub 2500} and M{sub 2500}, finding a power-law index of 1.06 ± 0.12 and a fractional intrinsic scatter in Y{sub 2500} at fixed mass of (25±9)%. While recent SZE scaling relations using X-ray mass proxies have found power-law indices consistent with the self-similar prediction of 5/3, our measurement stands apart by differing from the self-similar prediction by approximately 5σ. Given the good agreement between the measured Y{sub 2500}–Y{sub X} scalings, much of this discrepancy appears to be caused by differences in the calibration of the X-ray mass proxies adopted for each particular analysis.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2019

Novel CO 2 -Selective Membranes for CO 2 Capture from <1% CO 2 Sources

The objective of this project is to develop a cost-effective design and fabrication process for a new membrane and its membrane modules that capture CO 2 from <1% CO 2 concentration sources. Synthesis of novel CO 2 -selective membranes using a cost-effective nanoporous polyethersulfone (PES) polymer support and coating a top layer of thin, highly selective, yet permeable amine-containing polymer membrane has been performed. Pilot-size membranes (about 14 inches in width, the change was made from lab-size membranes with about 6 inches by 6 inches to gain more progress) have been used to fabricate at least 3 pilot-size membrane modules (each about 14-inch long) for lab testing with the simulated gas mixture. The pilot membrane modules have been in commercial configurations, i.e., plate-and-frame (PF) and spiral-wound (SW), for a minimal pressure drop (<0.103 bar/meter (1.5 psi (pounds per square inch)/meter)). Both PF and SW modules fabricated gave similar performance and acceptable pressure drop results. We down-selected to the SW module for ease of manufacture.

2-stage process↗
DOE OSTI2016

A decam search for an optical counterpart to the LIGO gravitational-wave event GW151226

We report the results of a Dark Energy Camera optical follow-up of the gravitational-wave (GW) event GW151226, discovered by the Advanced Laser Interferometer Gravitational-wave Observatory detectors. Our observations cover 28.8 deg{sup 2} of the localization region in the i and z bands (containing 3% of the BAYESTAR localization probability), starting 10 hr after the event was announced and spanning four epochs at 2–24 days after the GW detection. We achieve 5σ point-source limiting magnitudes of i≈21.7 and z≈21.5, with a scatter of 0.4 mag, in our difference images. Given the two-day delay, we search this area for a rapidly declining optical counterpart with ≳3σ significance steady decline between the first and final observations. We recover four sources that pass our selection criteria, of which three are cataloged active galactic nuclei. The fourth source is offset by 5.8 arcsec from the center of a galaxy at a distance of 187 Mpc, exhibits a rapid decline by 0.5 mag over 4 days, and has a red color of i−z≈0.3 mag. These properties could satisfy a set of cuts designed to identify kilonovae. However, this source was detected several times, starting 94 days prior to GW151226, in the Pan-STARRS Survey for Transients (dubbed as PS15cdi) and is therefore unrelated to the GW event. Given its long-term behavior, PS15cdi is likely a Type IIP supernova that transitioned out of its plateau phase during our observations, mimicking a kilonova-like behavior. We comment on the implications of this detection for contamination in future optical follow-up observations.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1975

The SAS-3 X-ray observatory

The experiment section of the Small Astronomy Satellite-3 (SAS-3) launched in May 1975 is an X-ray observatory intended to determine the location of bright X-ray sources to an accuracy of 15 arc-seconds; to study a selected set of sources over a wide energy range, from 0.1 to 55 keV, while performing very specific measurements of the spectra and time variability of known X-ray sources; and to monitor the sky continuously for X-ray novae, flares, and unexpected phenomena. The improvements in SAS-3 spacecraft include a clock accurate to 1 part in 10 billion, rotatable solar panels, a programmable data format, and improved nutation damper, a delayed command system, improved magnetic trim and azimuth control systems. These improvements enable SAS-3 to perform three-axis stabilized observations of any point on the celestial sphere at any time of the year. The description of the experiment section and the SAS-3 operation is followed by a synopsis of scientific results obtained from the observations of X-ray sources, such as Vela X-1 (supposed to be an accreting neutron star), a transient source of hard X-ray (less than 36 min in duration) detected by SAS-3, the Crab Nebula pulsar, the Perseus cluster of galaxies, and the Vela supernova remnant.

Mayer, W. F.↗
NASA NTRS1978

Illumination control apparatus for compensating solar light

An illumination control apparatus is presented for supplementing light from solar radiation with light from an artificial light source to compensate for periods of insufficient levels of solar light. The apparatus maintains a desired illumination level within an interior space comprising an artificial light source connected to an electrical power source with a switch means for selectively energizing said light source. An actuator means for controlling the on-off operation of the switch means is connected to a light sensor which responses to the illumination level of the interior space. A limit switch carried adjacent to the actuator limits the movement of the actuator within a predetermined range so as to prevent further movement thereof during detection of erroneous illumination conditions.

Owens, L. J.↗
NASA NTRS2004

GUST LAT Multiwavelength Planning

Because gamma-ray astrophysics profits in powerful ways from multi-wavelength studies, the GLAST Large Area Telescope (LAT) Collaboration has started multiwavelength planning well before the scheduled 2007 launch. Many aspects of this program are of direct interest to observers using VERITAS and other atmospheric Cerenkov telescopes, whose capabilities complement those of GLAST. This talk with describe some of the current developmental concepts for GLAST LAT multiwavelength work, including release of data for transient sources, nearly-continuous monitoring of selected time-variable sources, pulsar timing, follow-on observations for source identification, coordinated blazar campaigns, and cross-calibration with other high-energy telescopes. Although few details are firm at this stage of preparation for GLAST, the LAT Collaboration looks forward to cooperation with a broad cross-section of the multiwave-length community. The GLAST Large Area Telescope is an international effort, with U.S. funding provided by the Department of Energy and NASA.

Thompson, D. J.↗
DOE OSTI2018

Radiography of Dry Cask Storage for Used Nuclear Fuel

Since the U.S. currently only approves of storing used nuclear fuel in pools or dry casks, the demand for dry cask storage is on the rise due to the continuous operation of currently existing nuclear plants which are reaching or have reached the capacity of their used fuel pools. With the rising demand comes additional pressure to ensure the integrity of dry cask systems. Visual inspection is costly and man-power intensive, so alternative nondestructive testing techniques are desired to insure the continued safe and effective storage of fuel. Several approaches being investigated by the University of Florida and the larger multi-university Department of Energy (DOE) Nuclear Energy University Program (NEUP) Integrated Research Project (IRP) are gamma or neutron radiography, both transmission based and interior source emission. Additionally muon radiography is discussed. This work leverages the well-established techniques in medical image reconstruction and applies them to a significantly larger scale with additional considerations due to the dense nuclear materials which serves as effective shields for radiation. Emission source radiography relies on the radiation that is emitted from the used fuel. The main advantage of this technique is the passive nature of the measurement. The fuel is already emitting radiation and only detectors are needed. Transmission radiography uses an external source of radiation to penetrate the side of the cask. Challenges include selecting the external source spectrum to avoid overlap with the spectrum emitted from the fuel, and ensuring the radiation dose limits do not exceed those mandated by the Nuclear Regulatory Commission (NRC). Benefits of this technique include better understanding of the source location allowing for clear image reconstruction, and isolation of the signal from surrounding radiation sources. Muon radiography takes advantage of the natural background flux coming from the interaction of the atmosphere with cosmic radiation. The technique is particularly effective at interrogating large dense objects as the highly energetic muons have smaller cross sections than most typical sources and energies used in nuclear engineering. The various techniques are discussed individually then the conclusion compares them. Finally, future work is identified.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2016

Selection and Validation of Alternate Slag Sources for Saltstone Production - 16145

To stabilize low activity salt solution produced at the Savannah River Site (SRS) the salt waste is mixed with a combination of fly ash (FA), ground granulated blast furnace slag (GGBFS), and ordinary Portland cement (OPC) to form a grout termed saltstone. Upon curing, the low activity waste is encapsulated within the hardened cementitious matrix. While the sources of the dry feed components have remained unchanged for several years, SRS was recently notified that its domestic source of GGBFS would no longer be available due to the shutdown of the steel making plant that produced the ferrous slag as a by-product. This shut-down follows a trend in the reduction of domestic ferrous slag sources. Alternate GGBFS vendors were sought and a program developed to validate the alternate sources for use in saltstone. GGBFS is primarily utilized in the construction industry as a replacement for OPC and the requirements of a GGBFS source, based on an American Society for Testing and Materials (ASTM) standard, are predominantly limited to demonstrating that the GGBFS replacement will provide equivalent strength in comparison to the baseline OPC-based concrete. This affords the construction industry significant flexibility with respect to the GGBFS source that can be used. In contrast, GGBFS has a role of significantly more importance when utilized in saltstone. In particular, the reducing blast furnace environment under which GGBFS is produced yields reducing species, such as sulfide (S{sup 2-}) and ferrous iron (Fe{sup 2+}), which are believed to facilitate the long-term immobilization of redox sensitive contaminants (e.g. technetium-99 ({sup 99}Tc)). In addition, a change in GGBFS source has the potential to impact the rheological properties and the reactive heat generation of the grout, which may adversely affect the ability to pump the grout to a Saltstone Disposal Unit (SDU) and the temperatures attained within an SDU, respectively. As such, alternate GGBFS sources for the processing of saltstone require significantly more scrutiny than is prescribed by the ASTM standard. Four alternate GGBFS sources were evaluated. All four sources met the ASTM requirements, only one source was considered viable for use in saltstone based on preliminary evaluation. The other three sources will require a more intensive assessment to determine their potential applicability. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
NASA NTRS2010

Closed Brayton Cycle Power Conversion Unit for Fission Surface Power Phase I Final Report

A Closed Brayton cycle power conversion system has been developed to support the NASA fission surface power program. The goal is to provide electricity from a small nuclear reactor heat source for surface power production for lunar and Mars environments. The selected media for a heat source is NaK 78 with water as a cooling source. The closed Brayton cycle power was selected to be 12 kWe output from the generator terminals. A heat source NaK temperature of 850 K plus or minus 25 K was selected. The cold source water was selected at 375 K plus or minus 25 K. A vacuum radiation environment of 200 K is specified for environmental operation. The major components of the system are the power converter, the power controller, and the top level data acquisition and control unit. The power converter with associated sensors resides in the vacuum radiation environment. The power controller and data acquisition system reside in an ambient laboratory environment. Signals and power are supplied across the pressure boundary electrically with hermetic connectors installed on the vacuum vessel. System level analyses were performed on working fluids, cycle design parameters, heater and cooling temperatures, and heat exchanger options that best meet the needs of the power converter specification. The goal is to provide a cost effective system that has high thermal-to-electric efficiency in a compact, lightweight package.

Fuller, Robert L.↗