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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 1,225 records · Page 68
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Systems and methods for miniaturized drawbar extension springs

Extension springs that can be manufactured to a small size with a precise free length are described herein. An extension spring comprises a first drawbar member and a second drawbar member that extend along a same direction. The extension spring further comprises a compression spring coil that surrounds respective portions of the draw bar members. At either end of the spring coil are positioned end caps that surround the drawbar members. The end caps provide flat surfaces on which the ends of the spring coil rest in a resting position of the extension spring. The end caps are held against bent ends of arms of the drawbar members by tension of the spring coil. When the drawbar members are drawn apart from one another, the end caps compress the spring coil. Compression of the spring coil causes forces that resist the motion of the drawbar members apart from one another.

42 ENGINEERING↗
DOE OSTI2021

Tamper-resistant fastener

A tamper-resistant threaded fastener including a circular head having a slot formed in the head transverse to the longitudinal axis, the slot having an enlarged region intermediate an apex and a base of the slot. A cap member includes a head having a drive feature formed therein, the head extending to a first shank portion, extending to an enlarged second shank portion, extending to a foot. The cap member is insertable in the slot only from a direction transverse to the longitudinal axis. During rotational installation of the fastener and cap member in a threaded counterbored opening for securing a barrier for protecting an asset, the foot shears inside the slot at a predetermined rotational drive force, the cap member being rotatable in the opening and protectively covering the fastener head.

Neidigk, Stephen↗
DOE OSTI2021

Target unit with ceramic capsule for producing cu-67 radioisotope

A target unit for producing Cu67 radioisotope is described herein, and comprises a cage body releasably coupled to a screw-on cap; and a ceramic capsule containing a solid Zn68 target ingot and having one open end and one closed end and defining an interior chamber for the target ingot. The ceramic capsule is releasably contained between the cage body and the screw-on cap with a lid disposed on the open end of the capsule and a washer positioned between the lid and the screw-on cap. The screw-on cap and the washer provide a water-tight seal between the lid and the capsule. The interior of the capsule is in intimate physical contact with the target ingot; and the Zn68 of the target ingot is free of traces of residual oxygen that interfere with contact of the Zn68 to the capsule.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2022

Shock test assembly

An assembly for shock testing a specimen, the assembly including first and second opposing brackets and opposing lower and upper caps. The opposing brackets include lower and upper angled surfaces. The lower cap includes lower angled surfaces configured to engage the lower angled surfaces of the left and right brackets. The upper cap includes upper angled surfaces configured to engage the upper angled surfaces of the left and right brackets. The first and second brackets are configured to be drawn toward each other via fasteners, thereby wedging the lower and upper caps toward each other against the specimen.

Busenitz, Clark↗
DOE OSTI2023

Shock test assembly

An assembly for shock testing a specimen, the assembly including first and second opposing brackets and opposing lower and upper caps. The opposing brackets include lower and upper angled surfaces. The lower cap includes lower angled surfaces configured to engage the lower angled surfaces of the left and right brackets. The upper cap includes upper angled surfaces configured to engage the upper angled surfaces of the left and right brackets. The first and second brackets are configured to be drawn toward each other via fasteners, thereby wedging the lower and upper caps toward each other against the specimen.

Busenitz, Clark↗
DOE OSTI2015

Centre de la manche disposal facility after ten years of institutional control - 15255

Centre de la Manche disposal facility is the first French surface disposal facility for low and intermediate level short lived radioactive waste. It has been operated for 25 years, from 1969 to 1994. The facility was licensed for the institutional control period in 2003. As there were significant changes in the design of vaults or in waste acceptance criteria during the 25 years of operation, it was decided to implement a capping system including a bituminous membrane that would be able to sustain strains that might be caused by the settlement of waste packages in the eldest parts of the facility, where conditioning modes were different than those as presently practiced. In 2008 Andra submitted to ASN, the regulatory body in France, a file related to the safety of the facility including a study of the opportunity to modify capping system. Andra's project was to improve long term watertightness and to stabilize the sides of the cover by smoother slopes through a progressive approach. This file was completed in early 2015 by a progress report providing in particular results on studies related to the durability of the bituminous membrane. They take into account periodical measurements performed on samples of the membrane extracted from the capping system and studies performed on the phenomenology of ageing of the membrane. These data support the strategy of improvement of the capping system developed by Andra in order to achieve a more passive surveillance. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2015

25 years of environmental remediation in the general separations area of the Savannah river site: lessons learned about what worked and what did not work in soil and groundwater cleanup - 15270

The Savannah River Site, which is owned and administered by the US Department of Energy, covers approximately 900 square kilometers. The General Separation Area is located in the center of the site and includes: radioactive material chemical separations facilities, radioactive waste tank farms, radioactive seepage basins, and the radioactive waste burial grounds. Radioactive wastes were disposed in the General Separation Area from the mid-1950's through the mid-1990's. Operations at the F Canyon began in 1954 and at H Canyon began in 1955. Waste water disposition to the F and H Seepage Basins began soon after operations started in the canyons. The Old Radioactive Waste Burial Ground began operations in 1952 to manage solid waste that could be radioactive from all the site operations, and ceased receiving waste in 1972. The Mixed Waste Management Facility and Low Level Radioactive Waste Disposal Facility received radioactive solid waste from 1969 until 1995. Environmental legislation enacted in the 1970's through 1990's led to changes in waste management and environmental cleanup practices. The US Congress passed the Clean Air Act in 1970 and the Clean Water Act in 1972; the Resource Conservation and Recovery Act was enacted in 1976; the Comprehensive Environmental Response Compensation, and Liability Act was enacted by Congress in 1980; and the Federal Facilities Compliance Act was signed into law in 1992. Environmental remediation at the Savannah River Site essentially began with a 1987 Settlement Agreement between the Savannah River Site and the State of South Carolina. The site manages several of the larger groundwater remedial activities under the Resource Conservation and Recovery Act for facilities recognized early on as environmental problems. All subsequent remediation projects are managed under a tri-party agreement (Department of Energy, Environmental Protection Agency, and South Carolina Department of Health and Environmental Control) through the Federal Facilities Agreement. Environmental remediation activities during the past 25 years have stabilized and capped seepage basins as well as consolidated and capped waste units and burial grounds in the General Separation Area. Groundwater activities include: pump and treat systems in the groundwater, installation of deep subsurface barrier systems to manage groundwater flow, in situ chemical treatments in the groundwater, and captured contaminated groundwater discharges at the surface for management in a forest irrigation system. Concentrations of contaminants in the aquifers beneath the General Separation Area and in surface water streams in the General Separation Area have decreased over the past 25 years. Closure of 65 waste sites and 4 Resource Conservation and Recovery Act facilities has been successfully accomplished. Environmental clean-up has progressed to the stage where most of the work involves monitoring, optimization, and maintenance of existing remedial systems. Many lessons have been learned in the process of remediating the General Separations Area. Geo-textile covers outperform low permeability clay caps, especially with respect to the amount of repairs required to upkeep the drainage layers as the caps age. Passive and enhanced natural processes to address contamination are much more cost effective than pump and treat systems. Forest irrigation can be very effective in water management situations with non-accumulative contaminants such as tritium and volatile organic contaminants. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2019

Closure Device For a Containment Vessel in a Small Gram Quantity Shipping Package

SRNL has been chartered by DOE Environmental Management (DOE-EM) to develop a new Type B shipping package for Small Gram Quantities (SGQ) of radioactive material. Design a containment vessel (CV) closure device that will reduce the operation time and improve the ease-of- use for Operations Personnel. The Containment Vessel (CV) includes a closure lid cap with spring shaft and locking tabs, multiple disc springs, and vessel with integral locking ring. The CV is assembled by aligning the tabs on the lid cap with the openings in the locking ring. Next, the lid cap is pushed down to compress the disc springs. Finally, the lid is rotated 45-degrees to locking location. When released, the tabs are secured against the locking ring. Disc springs (e.g. Belleville washers, coned-disc springs, Belleville spring, etc.) exert axial loads on the mating parts when compressed. The orientation of the disc springs can be configured to change the deflection and axial loads for specific designs. In addition to securing the lid cap to the vessel, the compressed disc springs can be used to apply a load to a containment seal (e.g. o-ring). A prototype of the CV closure was 3D printed to evaluate the locking mechanism design and functionality. A test plan will be developed to evaluate the mechanical properties (i.e. compression forces) and functionality of the CV closure design.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2025

Advanced Computational Modeling of High-Level Waste Vitrification at the Hanford Site

The U.S. Department of Energy (DOE) has selected vitrification for stabilizing legacy tank waste at the Hanford site, where radioactive waste from plutonium production was historically stored in underground tanks. This waste will be separated into low-activity waste (LAW) and high-level waste (HLW) fractions and processed at the Waste Treatment and Immobilization Plant (WTP). At WTP, glass melters are used for the vitrification of radioactive tank waste, transforming it into a stable borosilicate glass form for safe long-term storage. The melter vessel is constructed from highly durable and heat-resistant materials, where the vitrification process occurs. The main regions that are modeled are the melt pool, plenum, cold cap, riser/discharge chamber, and surrounding structure with insulation layers. Forced convection induced by air bubblers at the base of the melter ensure uniform temperature distribution and provide heat to the cold cap layer. The cold cap is a region of reacting batch feed that floats on top of the molten glass and is where the batch-to-glass reactions occur. Joule heating provided by electrodes mounted along the vertical walls of the melter and immersed directly in the glass, generates the necessary heat for the net endothermic conversion processes that occur in the cold cap. The high temperatures, radioactivity, and opaque nature of the glass prevent direct observation inside the melters. Therefore, computational models are essential for providing insight into factors that affect melter throughput. Thermocouples in the plenum provide operators with plenum temperature measurements. Operational adjustments include bubbling rate, voltage supplied to the electrodes, feed adjustments, and glass removal rate. Different computational fluid dynamics (CFD) models have been developed, each serving a specific purpose. There are CFD models of different scale melters, as well as models that capture the two-phase flow interfaces of rising bubbles in the molten glass or models with a simplified molten glass region so that the surrounding structure and plenum can be feasibly incorporated. Pilot-scale melter models have been developed to serve as validation of the methods employed in the simulation of the full-scale WTP melters. Models incorporating resolved bubbling are used to develop momentum source terms to implement into a single phase, multi-region, steady-state flow model that is being validated by measured process parameters such as glass production rate, voltage, input power, plenum temperatures, etc. The resolved bubbling model uses the multiphase volume of fluid approach to model the system with a high-resolution interface capturing scheme to maintain sharp interfaces between the molten glass and the air phase. The suite of CFD models is continually being improved to incorporate more realistic physics and achieve faster turnaround time. For example, an incremental controller is implemented to automatically adjust electrode voltage within the simulation to a molten glass set point temperature of 1150°C. Newer models feature improved meshes to ensure conformal meshes between regions and eliminate unnecessary mesh refinement in areas that are not of interest (such as boundary layers in offgas ports). Instead of explicitly modeling the structural, refractory, and insulation layers of the melter, a thermal resistance approach is used with published correlations used for boundary conditions. The development of robust and efficient CFD models will be instrumental in enabling the WTP to successfully fulfill its mission of safely stabilizing legacy nuclear waste.

12 - MGMT OF RADIOACTIVE AND NON-RADIOACTIVE WASTE↗
DOE OSTI2024

Ultrathin Magnesium-Based Coating as an Efficient Oxygen Barrier for Superconducting Circuit Materials

Scaling up superconducting quantum circuits based on transmon qubits necessitates substantial enhancements in qubit coherence time. Over recent years, tantalum (Ta) has emerged as a promising candidate for transmon qubits, surpassing conventional counterparts in terms of coherence time. However, amorphous surface Ta oxide layer may introduce dielectric loss, ultimately placing a limit on the coherence time. In this study, a novel approach for suppressing the formation of tantalum oxide using an ultrathin magnesium (Mg) capping layer is presented. Synchrotron-based X-ray photoelectron spectroscopy studies demonstrate that oxide is confined to an extremely thin region directly beneath the Mg/Ta interface. Additionally, it is demonstrated that the superconducting properties of thin Ta films are improved following the Mg capping, exhibiting sharper and higher-temperature transitions to superconductive and magnetically ordered states. Moreover, an atomic-scale mechanistic understanding of the role of the capping layer in protecting Ta from oxidation is established based on computational modeling. Further, this work provides valuable insights into the formation mechanism and functionality of surface tantalum oxide, as well as a new materials design principle with the potential to reduce dielectric loss in superconducting quantum materials. Ultimately, the findings pave the way for the realization of large-scale, high-performance quantum computing systems.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Criteria Air Pollutants and Greenhouse Gas Emissions from Hydrogen Production in U.S. Steam Methane Reforming Facilities

The global and U.S. domestic effort to develop a clean energy economy and curb environmental pollution incentivizes the use of hydrogen as a transportation fuel, owing to its zero tailpipe pollutant emissions and high fuel efficiency in fuel cell electric vehicles (FCEVs). However, the hydrogen production process is not emissions free. Conventional hydrogen production via steam methane reforming (SMR) is energy intensive, coproduces carbon dioxide, and emits air pollutants. Therefore, it is necessary to quantify the environmental impacts of SMR hydrogen production alongside the use-phase of FCEVs. This study fills the information gap, analyzing the greenhouse gas (GHG) and criteria air pollutant (CAP) emissions associated with hydrogen production in U.S. SMR facilities by compiling and matching the facility-reported GHG and CAP emissions data with facilities’ hydrogen production data. The actual amounts of hydrogen produced at U.S. SMR facilities are often confidential. Thus, we have developed four approaches to estimate the hydrogen production amounts. The resultant GHG and CAP emissions per MJ of hydrogen produced in individual facilities were aggregated to develop emission values for both a national median and a California state median. Lastly, this study also investigates the breakdown of facility emissions into combustion emissions and noncombustion emissions.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2025

Multifunction Hydrophobic Ligand Engineered Cd(S, Se)/ZnS Quantum Dots for Stabilizing Highly Efficient Carbon‐Based Perovskite Solar Cells

The long-term operational stability of perovskite solar cells (PSCs) remains a key challenge impeding their commercialization, particularly due to ambient environments (e.g., moisture, oxygen, heat)-induced degradation. Carbon electrode-based PSCs have emerged as cost-effective and relatively stable alternatives to metal electrode-based devices due to carbon materials' hydrophobic behavior, yet they still lag in both long-term durability and power conversion efficiency (PCE). In this work, an ultrathin hydrophobic ligand-modified core–shell Cd(S,Se)/ZnS quantum dots (QDs) capping layer is introduced as a multifunctional interfacial modifier for carbon-electrode-based PSCs. This oleic acid ligand-modified QDs capping layer exhibits inherent hydrophobicity, effectively serving as a moisture barrier to retard perovskite degradation under ambient conditions. Furthermore, the strong interfacial bonding between the QDs and perovskite halide surfaces leads to efficient trap state passivation, reducing trap density and creating a more uniform electrical contact. The modified QDs/perovskite interface also features an elevated conduction band edge, promoting improved charge extraction. As a result, devices incorporating this quantum dot capping layer retain 98% of their initial PCE after 450 h of ambient aging and achieve a champion efficiency of 20.74%. As a result, this strategy highlights the potential of hydrophobic ligand-modified chalcogenide QDs as surface modifiers to enhance both the stability and performance of carbon-based PSCs, offering a promising route toward scalable fabrication of durable perovskite solar modules.

14 SOLAR ENERGY↗
DOE OSTI2020

Thermally Activated Adsorption in Metal–Organic Frameworks with a Temperature‐Tunable Diffusion Barrier Layer

Abstract Modification of the external surfaces of metal–organic frameworks offers a new level of control over their adsorption behavior. It was previously shown that capping of MOFs with ethylenediamine (EDA) can effectively retain small gaseous molecules at room temperature. Reported here is a temperature‐induced variation in the capping‐layer gate‐opening mechanism through a combination of in situ infared experiments and ab initio simulations of the capping layer. An atypical acceleration and increase in the loading of weakly adsorbed molecules upon raising the temperature above room temperature is observed. These findings show the discovery of novel temperature‐dependent kinetics that goes beyond standard kinetics and suggest a new avenue for tailoring selective adsorption by thermally tuning the surface barrier.

Tan, Kui↗
DOE OSTI2020

Thermally activated adsorption in metal–organic frameworks with a temperature–tunable diffusion barrier layer

Modification of the external surfaces of metal organic frameworks offers a new level of control over their adsorption behavior. Here, we have previously shown that capping of MOFs with ethylenediamine (EDA) can effectively retain small gaseous molecules at room temperature. Here, we report a temperature–induced variation in the capping–layer gate opening mechanism through a combination of in situ IR experiments and ab initio simulations of the capping layer. We find an atypical acceleration and increase in the loading of weakly adsorbed molecules upon raising the temperature above room temperature. Our findings show the discovery of a novel temperature–dependent kinetics that goes beyond standard kinetics and suggest a new avenue for tailoring selective adsorption by thermally tuning the surface barrier.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Design of a Short Thermally Stable α‐Helix Embedded in a Macrocycle

Abstract Although helices play key roles in peptide–protein and protein–protein interactions, the helical conformation is generally unstable for short peptides (10–15 residues) in aqueous solution in the absence of their binding partners. Thus, stabilizing the helical conformation of peptides can lead to increases in binding potency, specificity, and stability towards proteolytic degradation. Helices have been successfully stabilized by introducing side chain‐to‐side chain crosslinks within the central portion of the helix. However, this approach leaves the ends of the helix free, thus leading to fraying and exposure of the non‐hydrogen‐bonded amide groups to solvent. Here, we develop a “capped‐strapped” peptide strategy to stabilize helices by embedding the entire length of the helix within a macrocycle, which also includes a semirigid organic template as well as end‐capping interactions. We have designed a ten‐residue capped‐strapped helical peptide that behaves like a miniprotein, with a cooperative thermal unfolding transition and T m ≈70 °C, unprecedented for helical peptides of this length. The NMR structure determination confirmed the design, and X‐ray crystallography revealed a novel quaternary structure with implications for foldamer design.

Wu, Haifan↗
DOE OSTI2015

Biodeactivation of Lipopolysaccharide Correlates with Surface‐Bound NO 3 After Cold Atmospheric Plasma Treatment

Cold atmospheric plasma (CAP) treatment of biological surfaces results in important changes of biological functions, but little knowledge on specific surface‐chemical changes is available. We measured surface‐bound NO 3 on polymer and biomolecular films after CAP treatment. An O 2 /N 2 ‐based surface microdischarge was used to deactivate lipopolysaccharide (LPS), an immune‐stimulating biomolecule found in Gram negative bacteria. The observed LPS biodeactivation was highest for low N 2 concentrations in O 2 , increased roughly linearly with surface NO 3 , and then saturated. NO 3 was also observed after treatment by a very different source: an atmospheric pressure plasma jet operating with an Ar carrier gas. Thus, NO 3 formation is a generic surface chemical modification of these materials by CAP sources.

Bartis, Elliot A. J.↗
DOE OSTI2018

Suggestion of an Indicator to Evaluate Material Deposition in Resistance Spot Welding: Weld–Surface Interaction Index

Resistance spot welding (RSW) is still leading joining process in the automotive industry due to the simplicity and speed of the process. On the other hand, galvanized steel sheets provide improvement in corrosion resistance of the auto body. Material deposition has an influence on the corrosion resistance and weld strength; however, in the literature very little effort has been made to identify any weld–surface interaction numerically. In this study, a numerical approach called “Weld–Surface Interaction Index” (I{sub WSI}) has been introduced to investigate the effect of material deposition on the corrosion sensitivity of the welding zone and its periphery. A systematic investigation was carried out to better understand the effects of an electrode cap–galvanized steel sheet interface on the corrosion resistance of spot-welded steel. The chemical composition of DP600 steel sheet and Z-Trode electrode cap was analyzed by using a spectrometer. The specimens were then joined by using same caps up to 1200 welds. SEM–EDS analysis was also performed on the chosen specimens to determine the weight percentages (wt.%) of Fe, Zn and Cu. EDS analysis results and coefficient of variation wt.% of Fe, Zn and Cu were used to compose I{sub WSI} formula. In the proposed formula, wt.% of Zn represented resistivity of the cover to corrosion, while wt.% of Fe represents the vulnerability.

36 MATERIALS SCIENCE↗