Search NASA⌕ Search

SEARCH · Search NASA

Results for “Process Selection”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 541 records · Page 30
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Plutonium Retention by Crystalline Silicotitanate under Hyperalkaline Conditions Relevant to Tank-Side Cesium-Removal at the Hanford Site

Crystalline silicotitanate (CST) is used in Hanford’s Tank-Side Cesium-Removal (TSCR) process to selectively remove Cs-137 from highly caustic, nitrate-rich tank supernatants. Recent testing with actual waste samples suggests that CST can also retain measurable plutonium (Pu), which could affect radiological classification and disposal pathways for spent CST. To quantify this behavior, Pu partitioning to CST was studied under Hanford-relevant conditions using batch-contact experiments in a representative simulant (2 M NaNO3, 0.7 M NaOH). Isotherm data were measured and distribution ratios calculated, with Cs+ uptake used as benchmark. Under low-carbonate conditions, Pu was retained strongly by CST in systems initially contacted with either PuO2 nanoparticles (Pu(IV)) or aqueous Pu(VI), with distribution ratios of ~2,200–3,700 mL/g, generally exceeding those for Cs+ (~400–1,000 mL/g). Increasing carbonate concentration strongly reduced PuO2 nanoparticle retention; at [Na2CO3] = 1 M, distribution ratios decreased by up to one order of magnitude to roughly 100–300 mL/g. Electron microscopy suggests that Pu retention involves a combination of mechanisms such as PuO2 NP aggregation induced by CST leachate components, and association with CST bead surfaces.

Neumann, J.↗
DOE OSTI2024

EFRC Accomplishments: Integrated Mesoscale Architectures for Sustainable Catalysis (IMASC)

The vision of IMASC is to advance the fundamental science necessary to alter fundamental aspects of the chemical industries sector and its carbon footprint. The IMASC mission is to develop design principles for increasing the efficiency of key chemical syntheses using dilute alloy catalysts by quantitatively scaling from model studies to catalytic operation using advanced experiment and theory. One of the major challenges in catalysis is predicting catalytic behavior—especially selectivity. The IMASC team developed a methodology for obtaining critical information for selected catalytic processes using dilute alloy catalysts, that is widely applicable to modeling catalytic processes.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Integrated Methane Monitoring Platform Extension, Volume I: Final Technical Report

The IMMPE project, DE-FE0032284, was to enhance methane monitoring technologies and their applications across various natural gas asset classes. The scope included deploying advanced methane detection and monitoring technologies to identify and mitigate fugitive methane emissions, measuring emission rates, and assessing impacts. The findings included the successful mitigation of identified emissions and quantification of emission rates. A key outcome was the development of a comprehensive template and summary of recommendations for methane emissions monitoring, which is replicable for both upstream and downstream applications. Furthermore, the project emphasized the importance of education by providing training opportunities for technicians and regulators, thereby fostering awareness and promoting the adoption of cost-effective methane emissions monitoring and management techniques.

02 PETROLEUM↗
DOE OSTI2025

Plateau to River Model Predictive Simulations for All Ensemble Realizations to Support Modeling Work in Fiscal Year 2025

The purpose of this environmental calculation file (ECF) is to document predictions of flow and hydraulic head on the Central Plateau of the Hanford Site using the Plateau-to-River (P2R) Model (CP-57037, Model Package Report for the Plateau-to-River Model: Version 9.1). This calculation documents the simulation of the groundwater for the parent model domain of the P2R Model as a basis for use in other applications of the P2R Model. This application is unique from the standpoint that it will simulate all ensemble member models of the P2R Model whereas other applications may only utilize specific ensemble members. These simulations provide results that can be used in the process of selecting an appropriate subset of ensemble members for other applications.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2025

Development of High-Temperature Bonding Techniques to Enable High-Temperature Static or Dynamic Strain Measurements

Current light-water nuclear reactors rely on a variety of different sensors and sensor applications to meet their structural health monitoring needs throughout the entirety of the reactor primary, secondary, and containment systems. Optical fiber–based sensor technologies could provide solutions to reduce the sensor system footprint while enhancing the measurement fidelity and spatial resolution by leveraging distributed monitoring techniques. Moreover, advanced reactors may require optical fiber–based sensors for structural health monitoring because their operating temperatures will exceed the limits of conventional transducers used to acquire dynamic strain or acoustic data in nuclear power plants. Therefore, this report describes experiments targeting the development of high-temperature bonding techniques that would allow for potentially long lengths of fibers to be bonded to metallic reactor components in advanced reactor systems. The high temperatures experienced within target application, next-generation nuclear reactors, necessitate a high-temperature resistant bond to limit the amount of tension on the fiber at the target application temperature. The primary bonding method investigated in this work is brazing; hot-rolling has also been investigated to a lesser extent. Both techniques are well-suited to bonding optical fibers to large reactor components such as primary coolant piping, pressure vessels, or heat exchangers. Optical frequency domain reflectometry was used to monitor the strain in metal-coated optical fibers before, during, and after the high-temperature bonding process. On select optical fibers that were successfully bonded, additional thermal cycling was performed to assess the extent to which the fiber remained bonded based on the expected thermal expansion of the test specimen material. The results of the various experiments yielded the following general conclusions: (1) brazing is a viable technique for bonding and allows significant compressive strain to be applied to the fiber at room temperature; (2) hot-rolling is a viable technique as well, which has been more optimized than the brazing technique for bonding, but less residual compressive strain has been observed with this technique; and (3) both techniques will need further development and optimization to demonstrate bonding of a long length of fiber that can provably operate at relevant temperatures for an advanced nuclear reactor application.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2025

Suppressed paramagnetism in amorphous Ta 2 O 5 − x oxides and its link to superconducting-qubit performance

Amorphous-oxide layers in thin-film capacitors are linked to reduced transmon-qubit T 1 coherence times. Ta -based capacitors outperform Nb -based ones, suggesting that amorphous Ta 2 O 5 − x is less lossy than Nb 2 O 5 − x . We investigate the microscopic features of these amorphous oxides using ab initio molecular dynamics and density functional theory, revealing the origins of the superior performance of Ta 2 O 5 − x . We establish that oxygen deficiency is less likely to occur in amorphous Ta 2 O 5 − x than in Nb 2 O 5 − x for 0 ≤ x ≤ 0.25 and that for a given oxygen deficiency x , metal Ta — Ta bond formation is enhanced. Such bonds, which are accommodated by structural flaws in the amorphous network, capture electrons better than in amorphous Nb 2 O 5 − x . These thermochemical differences quench or highly suppress magnetic moments in amorphous Ta 2 O 5 − x and eliminate a potential source of quasiparticles and magnetic flux noise. We also show that hyperfine couplings between Nb nuclei and local magnetic moments in Nb 2 O 5 − x can form “two-level systems” (TLSs) or “two-level fluctuators” with energy splittings of 100–1000 MHz or higher. This reveals a TLS mechanism in amorphous Nb 2 O 5 − x oxide layers that is likely inactive in Ta 2 O 5 − x . Our work provides a fundamental understanding of the materials chemistry and limitations imposed by native oxides of superconducting qubits that can be used to guide materials selection and processing.

Pritchard, P. Graham [Northwestern U.] (ORCID:0000↗
NASA NTRS1963

Comet Intercept Study

STL (Space Technology Laboratories, Inc.) has been studying, during the past year, the problems of carrying out a comet intercept mission. During the course of this study, the properties of 31 short-term comets have been examined to determine the feasibility of a mission to any of them during the next 15 years. In the process of selecting these comets, injection energies for each of these comets at a suitable launch period were determined. In addition, the distance of the earth at intercept, the transit and flight times, and the guidance requirements were evaluated. Also, to determine the effectiveness of such a mission, possible scientific instruments which could be used to measure the various characteristics of the comets have been studied. Finally, to determine the present feasibility of such a mission, the payload capability of available boosters was examined, and a spacecraft configuration with appropriate subsystems was also studied.

INTERCEPTION↗
NASA NTRS1970

Photoionization mass spectrometer

Photoionization source with a vacuum UV monochromator is used in ion reaction kinetics. Monochromator passes only the photon energies near the threshold of the selected ionization process. Absence of electron impact alleviates creation of different type ions that result in ion fragmentation.

Warneck, P.↗
NASA NTRS1971

The development and evaluation of a cobalt base oxidation resistant dispersion strengthened alloy

The Co-18Cr-20Ni-4 Vol % ThO2 powders were prepared by a flash drying selective reduction process starting with an aqueous solution of metal salts and colloidal thoria. Powders were consolidated and extruded into rods with a minimum density of 99% of theoretical. Swaging and annealing studies were conducted to determine the conditions that would lead to a product with high stress-rupture strength. The best process yielded a stress-rupture life of 7.2 hours at 10 KSI (69 MN sq m and 2000 F (1094 C). The alloy recrystallized to a duplex (coarse-fine) structure and thus did not exhibit the desired strength of 3000 hours at 15 KSI (103.5MN/sq m and 2000 F (1094 C).

Irani, K. K.↗
NASA NTRS1972

Dynamic load simulator

Concepts and techniques for identifying and simulating both the steady state and dynamic characteristics of electrical loads for use during integrated system test and evaluation are discussed. The investigations showed that it is feasible to design and develop interrogation and simulation equipment to perform the desired functions. During the evaluation, actual spacecraft loads were interrogated by stimulating the loads with their normal input voltage and measuring the resultant voltage and current time histories. Elements of the circuits were optimized by an iterative process of selecting element values and comparing the time-domain response of the model with those obtained from the real equipment during interrogation.

Joncas, K. P.↗
NASA NTRS1972

Oxidation protected carbon-carbon

Pyrolized carbon-carbon has one unique advantage over other materials that makes its application to the space shuttle thermal protection system very attractive. This unique characteristic is the increase in material strength and modulus with increase in temperature up to about 2500 K (4040 F). Offsetting this unique advantage are disadvantages which include brittleness, high cost, and the tendency of the material to react with oxygen, particularly at high temperatures. The development of an oxidation inhibitor for the material and the definition of fabrication processes for selected full-scale components are considered.

Pavlosky, J. E.↗
NASA NTRS1972

A simplified correlation technique for position location using earth satellites.

To derive range to a moving vehicle for surveillance and navigation purposes, the phase delays in sets of sinusoidal tones may be measured using synchronous satellites for signal relay. When the number of users is large, problems of rapid acquisition and measurement occur in multiple-access systems. This paper describes the selection and processing of an orthogonal tone set which has several useful features. The paper also presents a simulation of a simplified digital technique for the noise-free case, as well as for a composite signal buried in wideband noise. The digital simulation is also modified to include the proposed 'hard limiting' or clipping technique.

Martin, S. C.↗
NASA NTRS1973

Seasonal changes of littoral transport and beach width and resulting effect on protective structures

The shorelines of Maryland's portion of the Chesapeake Bay exhibit seasonal changes in direction of littoral transport and resulting beach width. Observation and study of this process at selected locations emphasizes the necessity of study for a complete year's seasonal cycle before stating erosion rates of an area to be protected by structures and the cyclincal presence or absence of beaches. Seasonal beach conditions at four selected sites are described along with resulting physical changes to protective structures. Through the use of ERTS-1 multi-spectral photography, it will be possible to make widespread predictions elsewhere in the Bay as a direct aid in protective structure design.

Slaughter, T. H.↗
NASA NTRS1974

Skylab report - Man's role in space research

Some of the early results reported by several investigators in the solar physics discipline are described, as well as a subjective response to long-term zero-gravity exposure in several areas related to medical studies. Many of the roles in which man has participated in research aboard Skylab will again be important in future space activities such as the Space Shuttle. Examples are pointing, alignment, transient identification and response, and assurance of data quality. These tasks can be extended to include a greater role in data management and interpretation, so that some selectivity or processing, or both, might be appropriate onboard the spacecraft, prior to transmission of data to the ground.

Garriott, O. K.↗