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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 253 records · Page 14
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Air Mobility Data & Reasoning Fabric

Throughout the world, especially in dense urban environments, the quality of life is being negatively impacted by ever growing commute time. Travel, beyond commuting, is increasingly driven by door-to-door challenges ? not just gate-to-gate considerations. Air Mobility may be an approach to address these challenges, as it can effectively convert our 2D mobility system to a 3D mobility system, vastly increasing mobility options.

Air mobility↗
NASA NTRSDate not supplied

ES2Vec: Earth Science Metadata Suggestions and Analogical Reasoning

As the volume of text-based Earth science research grows, it is increasingly possible to discover latent relationships in the literature. However, traditional methodologies are restricted by limited computational capabilities and intractable problem spaces. Advancements in natural language processing (NLP) have allowed us to use an extensive Earth science corpus to create a domain-specific word vector model, Es2Vec, which we have used to surface latent relationships between Earth science concepts and generate improved keyword tags. Earth science metadata keyword assignment is a challenging problem. Dataset curators select appropriate keywords from the Global Change Master Directory (GCMD) set of keywords. The keywords an are integral part of the search and discovery of these datasets. Hence, the selection of keywords is crucial to increasing the discoverability of datasets. Utilizing machine learning techniques, we provide users with automated keyword suggestions to complement manual selection. We trained a machine learning model that leverages the semantic embedding ability of Word2Vec models to process abstracts and suggest relevant keywords. A user interface tool we built to assist data curators in the assignment of such keywords is also described.

word vectors↗
NASA NTRSDate not supplied

Data and Reasoning Fabric (DRF)

DRF helps realize the full potential of future air mobility to advance human society. This information discovery and exchange ecosystem enables the transportation of people and cargo​ to places previously not served or underserved by aviation.

Aeronautics↗
DOE OSTI2025

From Machine Learning to Machine Reasoning: A Model-based Approach to Analyze Equipment Reliability Data

In current nuclear power plants (NPPs) a large amount of condition-based data which can be used to assess and monitor component health and performance. Assessing component health from such data can be performed with a large variety of methods. While the analysis of numeric data can be performed with several methods, the extraction of information from textual data remains a challenge. Currently employed natural language processing (NLP) methods do not really provide quantitative information that might be contained in IRs. In addition, the integration of numeric and textual data to identify possible causal relationships between data elements is still an unresolved challenge. This paper presents an approach to extract information from textual (e.g., incident or maintenance reports) and numeric data that relies on model based system engineer (MBSE) models. MBSE are diagrams designed to represent system and component dependencies (from both a form and functional point of view). In our approach, MBSE models emulate system engineer knowledge about component/system architecture. NLP methods are employed to perform syntactic and semantic analyses. Syntactic analysis analyzes the grammatical structure of a sentence while semantic analysis is designed to analyze the logic structure of a sentence. An innovative element of our approach is that semantic analysis uses MBSE models to identify links between textual elements. Similarly, numeric data is directly linked to elements of the MBSE models in order to map which functions are being monitored.

97 - MATHEMATICS AND COMPUTING↗
DOE OSTI2018

Physical Reasoning to Synchronize Electrical Signals and Related Diagnostics in Plasma Focus Devices

Plasma Focus (PF) devices as well as other similar pulsed discharge devices requires a variety of diagnostics for their proper control and optimization, including the voltage between electrodes, the time derivative of the discharge current, detection of X-rays and neutron emissions, and pulsed laser images (Shadow, Schlieren, interferograms). This article discusses the problem of the time reference of all these outputs and proposes specific techniques for synchronizing them based on sound physical grounds. The foundations of synchronization criterion are verified in several experiments on PF devices.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2019

Development of a High-Strength Low-Carbon Steel with Reasonable Ductility through Thermal Cycling

In this research work, cost-effective structural material synthesis routes have been adopted in the form of thermal cycling designed and applied on a low-cost material (AISI 1010 steel). The main synthesis route consists of two-step thermal cycling (designed with respect to iron–carbon phase diagram) combining short-duration holding in upper critical and intercritical temperature regimes and different cooling conditions (forced air cooling and ice-brine quenching). Accordingly, the adopted hierarchical design approach (from nanoscale onwards) with a combination of hard and soft phases (to attain an adequate balance between mutually exclusive strength and ductility properties) results in origin of a novel microstructure. The microstructure consists of dislocation-enriched martensite regions (possessing plate and lath morphologies in 1:4 ratio) containing nanosized cementite particles and α-ferrite regions containing submicroscopic cementite particles. As a consequence, an excellent combination of strength (UTS = 905 MPa) and ductility (%Elongation = 17) is achieved in the synthesized material.

36 MATERIALS SCIENCE↗
DOE OSTI2018

The reason for the low Ca2+-sensitivity of thin filaments associated with the Glu41Lys mutation in the TPM2 gene is “freezing” of tropomyosin near the outer domain of actin and inhibition of actin monomer switching off during the ATPase cycle

Highlights: • E41K mutation inhibits the “off”/”on” transition of the thin filaments. • Myosin heads lose ability to shift E41K-Tpm in the open position at high Ca{sup 2+}. • E41K-Tpm is shifted towards the blocked position during the ATPase cycle. • Switching on and off of actin monomers at high and low Ca{sup 2+} is inhibited. • Mutation inhibits the growth of the fraction of strongly bound S1 at high Ca{sup 2+}. The E41K mutation in TPM2 gene encoding muscle regulatory protein beta-tropomyosin is associated with nemaline myopathy and cap disease. The mutation results in a reduced Ca{sup 2+}-sensitivity of the thin filaments and in muscle weakness. To elucidate the structural basis of the reduced Ca{sup 2+}-sensitivity of the thin filaments, we studied multistep changes in spatial arrangement of tropomyosin (Tpm), actin and myosin heads during the ATPase cycle in reconstituted fibers, using the polarized fluorescence microscopy. The E41K mutation inhibits troponin's ability to shift Tpm to the closed position at high Ca{sup 2+}, thus restraining the transition of the thin filaments from the “off” to the “on” state. The mutation also inhibits the ability of S1 to shift Tpm to the open position, decreases the amount of the myosin heads bound strongly to actin at high Ca{sup 2+}, but increases the number of such heads at low Ca{sup 2+}. These changes may contribute to the low Ca{sup 2+}-sensitivity and muscle weakness. As the mutation has no effect on troponin's ability to switch actin monomers on at high Ca{sup 2+} and inhibits their switching off at low Ca{sup 2+}, the use of reagents that increase the Ca{sup 2+}-sensitivity of the troponin complex may not be appropriate to restore muscle function in patients with this mutation.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2021

Reasons for Declining Applicant Numbers in Radiation Oncology From the Applicants' Perspective: Results From the Applicant Concerns and Radiation Oncology Sources Survey (ACROSS)

Applications to radiation oncology in the United States have decreased the past 3 years, resulting in unfilled residency positions (30 [14.5%] in 2019 and 35 [18.5%] in 2020). The aim of this study is to understand the concerns among radiation oncology applicants and whether these concerns may have led to a decline in applications.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2017

Addressing as low as reasonably achievable (ALARA) issues: investigation of worker collective external and extremity dose data

Plutonium emits both neutrons and photons and when it is stored or handled inside a glovebox, both photons and neutrons are significant external radiation hazards. Doses to the extremities are usually dominated by gamma radiation in typical plutonium glovebox operations. Excess external dose can generates stochastic effects consisting of cancer and benign tumors in some organs. Direct doses from radiation sources external to the body are measured by thermoluminescent dosimeters (TLDs) placed on the glovebox worker between the neck and waist. Wrist dosimeters are used to assess externally penetrating radiation including neutrons and provide an estimate of neutron radiation exposure to the extremities. Both TLDs and wrist dosimeters are processed monthly for most glovebox workers. Here, worker collective extremity and external dose data have been analyzed to prevent and mitigate external radiation events through the use of Lean Manufacturing and Six Sigma business practices (LSS). Employing LSS, statistically significant variations (trends) are identified in worker collective extremity and external dose data. Finally, the research results presented in this paper are pivotal to the ultimate focus of this program, which is to minimize external radiation events.

61 RADIATION PROTECTION AND DOSIMETRY↗
DOE OSTI2013

Maximum Reasonable Radioxenon Releases from Medical Isotope Production Facilities and Their Effect on Monitoring Nuclear Explosions

Fission gases such as 133Xe are used extensively for monitoring the world for signs of nuclear testing in systems such as the International Monitoring System (IMS). These gases are also produced by nuclear reactors and by fission production of 99Mo for medical use. Recently, medical isotope production facilities have been identified as the major contributor to the background of radioactive xenon isotopes (radioxenon) in the atmosphere (Saey, et al., 2009). These releases pose a potential future problem for monitoring nuclear explosions if not addressed. As a starting point, a maximum acceptable daily xenon emission rate was calculated, that is both scientifically defendable as not adversely affecting the IMS, but also consistent with what is possible to achieve in an operational environment. This study concludes that an emission of 5×109 Bq/day from a medical isotope production facility would be both an acceptable upper limit from the perspective of minimal impact to monitoring stations, but also appears to be an achievable limit for large isotope producers.

07 ISOTOPE AND RADIATION SOURCES↗