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At least 1,531 records · Page 85
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

An Architectural Survey of the Area 25 Nuclear Rocket Development Station, Nevada National Security Site, Nye County, Nevada, Volume 3 Of 3

The purpose of the current architectural survey is to record the Nuclear Rocket Development Station (NRDS) district, which is recommended eligible for listing to the NRHP under all four criteria as the testing center for the Rover/NERVA (Nuclear Engine for Rocket Vehicle Application) program from the initial boundary survey in 1956 to the end of nuclear rocket development on January 5, 1973. Resources in the NRDS district were evaluated to determine if they are eligible for listing to the National Register as district contributors. The current survey identified the Reactor Control Point subdistrict to provide a temporal, spatial, and functional framework for organizing the resources involved in the NRDS operations. However, the subdistrict was not evaluated as a potential historic district against the Secretary of Interior’s Significance Criteria.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRSDate not supplied

Semantic Search with Sentence-BERT for Design Information Retrieval

Managing and referencing design knowledge is a critical activity in the design process. However, reliably retrieving useful knowledge can be a frustrating experience for users of knowledge management systems due to inherent limitations of standard keyword-based searches. In this research, we consider the task of retrieving relevant lessons learned from the NASA Lessons Learned Information System (LLIS). To this end, we apply a state-of-the-art natural language processing (NLP) technique for information retrieval: semantic search with sentence-BERT, which is a modification of a Bidirectional Encoder Representations from Transformers (BERT) model that uses siamese and triplet network architectures to obtain semantically meaningful sentence embeddings. While the pretrained sBERT model shows excellent out-of-the-box performance, we further fine-tune the model on data from the LLIS so that it learns on design engineering-relevant vocabulary. We quantify the improvement in query results using both standard sBERT and fine-tuned sBERT over the LLIS’s built-in keyword search. Additionally, we demonstrate a use case for the query system by searching for lessons learned relevant to specific requirements from a NASA project as part of a broader knowledge management and retrieval system. Results indicate that applying state-of-the-art natural language processing techniques, especially when fine-tuned using engineering data, to design information retrieval tasks shows significant promise in modernizing design knowledge management systems.

Hannah S. Walsh↗
NASA NTRSDate not supplied

A New Concurrent Engineering Tool for the New Mission Design Center at NASA Ames Research Center

The NASA Ames Mission Design Center (MDC) has undergone a significant transformation process in recent years, culminating in becoming a true Concurrent Engineering Center. The underlying goal of this transformation is to better serve the Ames PI community in a cost-effective and rapidly-responsive way, providing quality products pivotal to the decision-making proposal strategy of our center. The four pillars of the change focus on four areas: personnel, physical places, tools, and training. Personnel: the MDC switched from using a dedicated pool of engineers—mostly entry-level career—for a matrixed approach with more experienced Subject Matter Experts, usually involved in spaceflight projects. These SMEs get detailed to the MDC for the duration of the study on a part-time or full-time basis. Physical places: The physical aspect pertains mostly to the layout of the new Engineering building and the dedicated concurrent engineering layout to foster collaboration. The current plan includes a dedicated space for concurrent engineering sessions as well as dedicated project rooms for concept studies. Tool: the MDC team is developing a new in-house concurrent engineering tool to facilitate concurrent engineering sessions. The team leveraged the many lessons learned and insight gained from using the current concurrent engineering tool, in use since 2007. SMEs have been involved throughout its design and development, ensuring accuracy and providing validity to the implementation approach. This new tool is database-driven and allows a team to work concurrently on the same model of a mission concept. “Workspaces” are provided for each of the traditional spacecraft mission design disciplines, including cost accounting and systems engineering. There are multiple tiers of fidelity available within each workspace, which can be completed parametrically or independently from the other disciplines as needed or synchronously with the other disciplines. A “commit” step synchronizes a workspace with the mission database and identifies any potential conflicts, along with the user who entered the conflicting data. A Mission Summary workspace enables a Study Lead to run an effective CE session, displaying key graphics, workspace status information, and technical and monetary budget information. This new CE tool will be undergoing Beta Testing with its primary user base and a limited Parts database in the summer of 2020. The team plans to release the first fully operational version in December 2020. Training: working in early concept development and maturation for a space mission requires a unique mindset and being comfortable with uncertainties in an environment where requirements are not yet fully developed, and where changes and trade-offs happen at a high tempo. The MDC started a weekly training program to ensure a common knowledge base on how do develop and mature early concept studies, as well as how to operate in a concurrent engineering environment. In conclusion, the MDC transformation will provide the overall PI community focused on cost-effective small satellite scientific missions with a powerful tool to address and mature early concepts more effectively and efficiently.

David Mauro↗
DOE OSTI2026

Multi-system analysis of offshore geologic carbon storage: a review of open-source data science solutions

Geologic carbon storage projects are maturing worldwide and the footprint of deployment in the offshore is expanding. At present, there are ten projects in operation or that have been completed, more than 50 in construction and development, and dozens of characterization studies completed or underway. Offshore geologic carbon storage offers potential benefits over onshore geologic carbon storage. These offshore projects are generally remote in location, distant from population centers, and avoid complicated pore space rights while having abundant prospective storage potential. Some offshore fields targeted for carbon storage have comparatively fewer prior borehole penetrations except for areas that have been explored for petroleum production, minimizing potential issues such as pressure interference and infrastructure impacts. Yet offshore geologic carbon storage projects face distinctive technical and economic challenges, such as seafloor geohazards (e.g., seabed instability), expensive maritime transport, and meteorological-oceanographic conditions that can damage infrastructure and impact operations. Analytical capabilities and improved computational speeds have advanced engineering, earth and energy sciences in the wake of the arrival of modern data science over the last decade. These advancements have created an opportunity for integrated, multi-systems modeling approaches utilizing artificial intelligence and machine learning that are no longer limited by computational issues. Analytical tools developed alongside this advancement in data science can be leveraged to calibrate the potential advantages and challenges of carbon storage operations in the offshore. New methods and approaches that incorporate data science to analyze multiple aspects of engineered and natural systems can provide insights that complement the characterization and onsite engineering that traditional commercial and operational software addresses. These new methods and approaches can potentially improve the outcome of energy operations and carbon storage. Providing multi-system, science-driven data analytics enhances the knowledge base that offshore developers, operators, and regulatory bodies may draw from to improve offshore site selection and operational efficiency. Here, we provide a brief synopsis of geologic carbon storage efforts to date, an overview of the engineered and natural systems involved in offshore geologic carbon storage, and a review of publicly available, open-source, offshore and/or carbon storage related data- and science-driven tools developed by 2010 or later that are suitable for screening and assessing regions for offshore geologic carbon storage.

artificial intelligence↗
DOE OSTI2016

Metal hydrides for concentrating solar thermal power energy storage

The development of alternative methods for thermal energy storage is important for improving the efficiency and decreasing the cost of concentrating solar thermal power. We focus on the underlying technology that allows metal hydrides to function as thermal energy storage (TES) systems and highlight the current state-of-the-art materials that can operate at temperatures as low as room temperature and as high as 1100 °C. The potential of metal hydrides for thermal storage is explored, while current knowledge gaps about hydride properties, such as hydride thermodynamics, intrinsic kinetics and cyclic stability, are identified. Further, the engineering challenges associated with utilising metal hydrides for high-temperature TES are also addressed.

14 SOLAR ENERGY↗
DOE OSTI2017

Interfacial Phenomena and Mechanical Behavior of Polyetheretherketone/Polybenzimidazole Blend under Hygrothermal Environment

Demands for engineering applications of high performance polymers, such as the polyaryletherketone families, have grown significantly in recent years. Fundamental knowledge on the mechanical behavior of such polymers, especially under harsh environments, is still lacking. In this study, the mechanical behavior and interfacial phenomena of a blend of polybenzimidazole (PBI) particles having sizes of about 50 μm and polyetheretherketone (PEEK) matrix at 50:50 weight ratio was characterized. PBI and PEEK are known to be incompatible with each other in the dry state. The possible influence of hygrothermal exposure on interfacial bonding between PEEK and PBI has been systematically studied. Under dry conditions, the PEEK matrix dominates the dynamic mechanical behavior, indicating no noticeable viscoelastic coupling between the two phases. After being exposed to hygrothermal conditions, the T g of the PEEK phase in the blend shifts to a lower temperature by as much as 26 °C. The extent of this shift is much greater than what is observed for neat PEEK alone under the same condition. Nanomechanical property mapping results indicate that the interfacial region is broadened after 288 °C hot water immersion treatment. The above finding strongly suggests the hygrothermal conditioning promotes apparent compatibility between PEEK and PBI. Likewise, the fracture behavior of the blend provides direct evidence that the interfacial adhesion is greater than the cohesive strength of either phase after water immersion. In the meantime, it is found that both fracture toughness and tensile strength of the blend are improved by water absorption at 60 °C, at the expense of a minor reduction in Young’s modulus. However, if the blend is exposed to hot water at 288 °C, all of the mechanical properties will deteriorate significantly. In conclusion, the possible causes of the mechanical property deterioration in the PEEK/PBI blend after hygrothermal treatment are discussed.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Rewiring Aromatic Compound Consumption: Chromosomal Amplification and Evolution of a Foreign Pathway in Acinetobacter baylyi ADP1

Rational engineering strategies that seek to harness the remarkable diversity of microbial metabolism can be limited by incomplete biological knowledge. As described here, a novel approach to address this challenge involved replacing a native pathway for degrading lignin-derived aromatic compounds via ortho cleavage of protocatechuate in Acinetobacter baylyi ADP1 with a foreign meta-cleavage pathway that uses different enzymes, metabolites, and redox carriers. This alteration may improve lignin valorization and coordinate catabolism with bioproduction strategies. When a 14-kbp region of foreign DNA was inserted in the chromosome, the heterologous genes failed to confer growth on target substrates. Regional gene dosage was increased using a synthetic DNA fragment to promote recombination, and higher copy number enabled growth. During adaptive laboratory evolution, compensatory mutations arose that permit growth with one copy of the foreign genes. This complex metabolic remodeling was accomplished without assumptions about the impediments that initially prevented growth. To understand the changes that emerged, a novel transformation assay identified a combination of mutations sufficient for the new phenotype. Three unexpected changes were revealed: loss of one foreign enzyme, loss of one native enzyme, and loss of a two-component transcriptional regulatory system. This study establishes that large multicopy tandem arrays of poorly adapted pathway genes can confer new functions and improve understanding of metabolism.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Insights into the sonochemical synthesis and properties of salt-free intrinsic plutonium colloids

Fundamental knowledge on intrinsic plutonium colloids is important for the prediction of plutonium behaviour in the geosphere and in engineered systems. The first synthetic route to obtain salt-free intrinsic plutonium colloids by ultrasonic treatment of PuO 2 suspensions in pure water is reported. Kinetics showed that both chemical and mechanical effects of ultrasound contribute to the mechanism of Pu colloid formation. In the first stage, fragmentation of initial PuO 2 particles provides larger surface contact between cavitation bubbles and solids. Furthermore, hydrogen formed during sonochemical water splitting enables reduction of Pu(IV) to more soluble Pu(III), which then re-oxidizes yielding Pu(IV) colloid. A comparative study of nanostructured PuO 2 and Pu colloids produced by sonochemical and hydrolytic methods, has been conducted using HRTEM, Pu LIII-edge XAS, and O K-edge NEXAFS/STXM. Characterization of Pu colloids revealed a correlation between the number of Pu-O and Pu-Pu contacts and the atomic surface-to-volume ratio of the PuO 2 nanoparticles. NEXAFS indicated that oxygen state in hydrolytic Pu colloid is influenced by hydrolysed Pu(IV) species to a greater extent than in sonochemical PuO 2 nanoparticles. In general, hydrolytic and sonochemical Pu colloids can be described as core-shell nanoparticles composed of quasi-stoichiometric PuO 2 cores and hydrolyzed Pu(IV) moieties at the surface shell.

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

Contribution of electrolyte in nanoscale electrolysis of pure and buffered water by particulate photocatalysis

Photocatalysis using semiconductor powders in suspension performs reduction and oxidation reactions at nanometer-scale distances. Such short distances between the reduction (cathode) and the oxidation (anode) sites enable photocatalytic water splitting to generate H 2 and O 2 from pure water without a supporting electrolyte, which is otherwise impossible in conventional electrode systems due to the high solution resistance. A CrO x /Pt/SrTiO 3 model photocatalyst achieves high efficiency under UV irradiation in ultra-pure water splitting at rates (>1 μmol-H 2 per cm 2 per h) corresponding to electrocatalysis on the order of mA cm -2 . The introduction of an unbuffered supporting electrolyte did not improve the photocatalytic rates, consistent with the negligible ohmic losses (<1 mV) numerically calculated using the Poisson–Nernst–Planck equations. The Nernstian potential loss resulting from pH gradients became apparent at high photocatalytic rates (>100 mV when rate >1 μmol-H 2 per cm 2 per h) even when the distance between redox sites was below 10 nm. Substantial improvements in photocatalytic rates were observed when buffer ions were introduced into near-neutral pH media by not only circumventing pH gradients but introducing kinetically facile H + reduction to H 2 instead of the kinetically sluggish direct reduction of H 2 O to H 2 . In this work, the quantitative descriptions of the electric potential, concentration gradients, and catalytic performance in nanoscale water electrolysis are presented with emphasis on (1) the advantages of performing redox reactions at the nanoscale, (2) the use of electrolyte engineering at near-neutral pH as a universal and effective strategy, and (3) the effectiveness of transferring knowledge from electrocatalysis to photocatalysis, where the potential is quantitatively defined regarding the former and poorly quantified regarding the latter.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Weapon Systems Engineering Material Database Requirements

The Weapon Systems Engineering Material Database, often called ‘Granta’ (due to the use of Granta MI software by Granta Design) but referred to in this document as ‘the database’, stores and distributes material information to W-division at Los Alamos National Laboratory (LANL). The database is constantly evolving as data is imported and methods of retrieving data are developed. Because limited resources necessitate prioritization of data to be imported and retrieval method development, a definition is needed of how the database is to be used, both currently and in the future. This document, to be used by the database developers, is intended to provide that definition in the form of requirements for the database.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Unclassified Data Export from the Containment Database

The attached dataset is an unclassified subset of data copied from the CDB for release to a wider audience. It includes only the clearly unclassified columns from each of the tables in the CDB, and only the rows related to announced tests. Also included is a glossary that lists each of the tables and columns included in the export with its definition, historical labels, unit of measure, and reference information. Our objective is to make this unclassified dataset available for querying on an unclassified server through a repeatable process.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2021

The Building Adapter: Automatic Mapping of Commercial Buildings for Scalable Building Analytics

This project creates new solutions for the manual metadata mapping problem: the costly process of creating a match between a building’s sensor data streams and the inputs of a building analytics engine. This goal is achieved by creating and improving techniques for metadata inference: automatically constructing new contextual information for sensing and control points based on the sensor point names and the raw time series values. The objective is to enable vendors to apply building analytics to 90% of buildings with no manual mapping, and to 10% of buildings with a 90% reduction in manual mapping. These targets are set for all types of metadata required by current analytics engines, including type, location, equipment type, and other relationships. The outcome of this project is a suite of solutions to the manual mapping problem collectively called the Building Adapter that allows vendors to apply analytics engines to new buildings at a significantly reduced cost.

96 KNOWLEDGE MANAGEMENT AND PRESERVATION↗
NASA NTRS1984

High temperature static strain gage program

Development of electrical resistance strain gages for static strain measurements of nickel or cobalt superalloy parts inside a gas turbine engine on a test stand was inititated. Measurements of this type are of great importance because without reliable knowledge of the stresses and strains which exist in specific components, it will be difficult to fully appreciate where improvements in design and materials can be implemented. The first part of this effort consists of a strain gage alloy development program which will be followed by an investigation of complete strain gage systems. Efforts to date are summarized.

Hulse, C.↗
NASA NTRS1987

TDAS: The Thermal Expert System (TEXSYS) data acquisition system

As part of the NASA Systems Autonomy Demonstration Project, a thermal expert system (TEXSYS) is being developed. TEXSYS combines a fast real time control system, a sophisticated human interface for the user and several distinct artificial intelligence techniques in one system. TEXSYS is to provide real time control, operations advice and fault detection, isolation and recovery capabilities for the space station Thermal Test Bed (TTB). TEXSYS will be integrated with the TTB and act as an intelligent assistant to thermal engineers conducting TTB tests and experiments. The results are presented from connecting the real time controller to the knowledge based system thereby creating an integrated system. Special attention will be paid to the problem of filtering and interpreting the raw, real time data and placing the important values into the knowledge base of the expert system.

Hack, Edmund C.↗
NASA NTRS1990

Model authoring system for fail safe analysis

The Model Authoring System is a prototype software application for generating fault tree analyses and failure mode and effects analyses for circuit designs. Utilizing established artificial intelligence and expert system techniques, the circuits are modeled as a frame-based knowledge base in an expert system shell, which allows the use of object oriented programming and an inference engine. The behavior of the circuit is then captured through IF-THEN rules, which then are searched to generate either a graphical fault tree analysis or failure modes and effects analysis. Sophisticated authoring techniques allow the circuit to be easily modeled, permit its behavior to be quickly defined, and provide abstraction features to deal with complexity.

Sikora, Scott E.↗