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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 613 records · Page 34
All sourcesNASA NTRSDOE OSTI
NASA NTRS1995

Other Planetary Systems: The View From Our Neighborhood

The structure and contents of the Solar System offer an initial model for other planetary systems in this and other galaxies. Our knowledge of the bodies in the Solar System and their physical conditions has grown enormously in the three decades of planetary exploration. Parallel to the uncovering of new facts has been a great expansion of our understanding of just how these conditions came to be. Telescopic studies and missions to all the planets (except Pluto) have shown spectacular and unexpected diversity among those planets, their satellites, the asteroids, and the comets. Highlights include the organic-rich crust of comets, volcanic activity on planetary satellites, randomly oriented magnetic fields of the major planets, the existence of a huge population of planetesimals just beyond Neptune, dramatic combinations of exogenic and endogenic forces shaping the solid bodies throughout the Solar System, and much more. Simultaneously, computational, laboratory, and conceptual advances have shown that the Solar System is not fully evolved either dynamically or chemically. The discovery of clearly identified interstellar (presolar) material in the meteorites and comets connects us directly with the matter in the molecular cloud from which the Solar System originated. At the same time, an increased understanding of the chemistry of comets and the impact history of the planets has demonstrated the dependence of the origin and evolution of life on Earth on powerful exogenic factors. This presentation summarizes some of the new knowledge of the Solar System and proposes specific character ist ics that may be observed in (or used as criteria for identification of) extrasolar planetary systems.

Cruikshank, Dale P.↗
NASA NTRS2005

Effective Team Support: From Task and Cognitive Modeling to Software Agents for Time-Critical Complex Work Environments

The purpose of this research contract was to perform multidisciplinary research between CMU psychologists, computer scientists and NASA researchers to design a next generation collaborative system to support a team of human experts and intelligent agents. To achieve robust performance enhancement of such a system, we had proposed to perform task and cognitive modeling to thoroughly understand the impact technology makes on the organization and on key individual personnel. Guided by cognitively-inspired requirements, we would then develop software agents that support the human team in decision making, information filtering, information distribution and integration to enhance team situational awareness. During the period covered by this final report, we made substantial progress in completing a system for empirical data collection, cognitive modeling, and the building of software agents to support a team's tasks, and in running experiments for the collection of baseline data.

Remington, Roger W.↗
NASA NTRS2009

Proof of Concept Study of Trade Space Configuration Tool for Spacecraft Design

Spacecraft design is a very difficult and time consuming process because requirements and criteria are often changed or modified as the design is refined. Accounting for these adjustments in the design constraints plays a significant role in furthering the overall progress. There are numerous aspects and variables that hold significant influence on various characteristics of the design. This can be especially frustrating when attempting to conduct rapid trade space analysis on system configurations. Currently, the data and designs considered for trade space evaluations can only be displayed by using the traditional interfaces of Excel spreadsheets or CAD (Computer Aided Design) models. While helpful, these methods of analyzing the data from a systems engineering approach can be rather complicated and overwhelming. As a result, a proof of concept was conducted on a dynamic data visualization software called Thinkmap SDK (Software Developer Kit) to allow for better organization and understanding of the relationships between the various aspects that make up an entire design. The Orion Crew Module Aft Bay Subsystem was used as the test case for this study because the design and layout of many of the subsystem components will be significant in ensuring the overall center of gravity of the capsule is correct. A simplified model of this subsystem was created and programmed using Thinkmap SDK to create a preliminary prototype application of a Trade Space Configuration Tool. The completed application ensures that the core requirements for the Tool can be met. Further development is strongly suggested to produce a full prototype application to allow final evaluations and recommendations of the software capabilities.

Glidden, Geoffrey L.↗
DOE OSTI2022

Comprehensive compilations of computation results and validations for neutronics start-up tests at China Experimental Fast Reactor

This paper compiles and analyzes refined results of the coordinated research project (CRP) on Neutronics Benchmark of China Experimental Fast Reactor (CEFR) Start-Up Tests conducted by the International Atomic Energy Agency (IAEA) since 2018. Twenty-eight research organizations participated with various code systems. The China Institute of Atomic Energy (CIAE) provided the benchmark specifications and participants conducted the benchmark through blind and refined phases. This paper presents the benchmark results on six experimental measurements, criticality, control rod worth, temperature reactivity coefficients, sodium void worth, assembly swap reactivities, and foil activations. Except for a few outlier results, the simulation results show good agreement with the measured data within 1-σ experiment uncertainties. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2024

The accuracies of effective interactions in downfolding coupled-cluster approaches for small-dimensionality active spaces

Here, this paper evaluates the accuracy of the Hermitian form of the downfolding procedure using the double unitary coupled cluster (DUCC) ansatz on the benchmark systems of linear chains of hydrogen atoms, H6 and H8. The computational infrastructure employs the occupation-number-representation codes to construct the matrix representation of arbitrary second-quantized operators, allowing for the exact representation of exponentials of various operators. The tests demonstrate that external amplitudes from standard single-reference coupled cluster methods that sufficiently describe external (out-of-active-space) correlations reliably parameterize the Hermitian downfolded effective Hamiltonians in the DUCC formalism. The results show that this approach can overcome the problems associated with losing the variational character of corresponding energies in the corresponding SR-CC theories.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Microsecond Molecular Dynamics Simulations of Proteins Using a Quasi-Equilibrium Solvation Shell Model

In this work, we describe the development and implementation of a quasi-equilibrium hydration shell model of biomolecular solvation with adaptive boundaries. Applying the model to microsecond-long molecular dynamics simulations of several protein systems of varying complexity, we find that the model simulation results are of comparable quality to those obtained from simulations of fully solvated systems, but at a reduced computational cost. We discuss the dominant sources of error in the model and outline directions for future improvements.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Exact Coherent Structures and Phase Space Geometry of Preturbulent 2D Active Nematic Channel Flow

Confined active nematics exhibit rich dynamical behavior, including spontaneous flows, periodic defect dynamics, and chaotic “active turbulence.” Here, we study these phenomena using the framework of exact coherent structures, which has been successful in characterizing the routes to high Reynolds number turbulence of passive fluids. Exact coherent structures are stationary, periodic, quasiperiodic, or traveling wave solutions of the hydrodynamic equations that, together with their invariant manifolds, serve as an organizing template of the dynamics. We compute the dominant exact coherent structures and connecting orbits in a preturbulent active nematic channel flow, which enables a fully nonlinear but highly reduced-order description in terms of a directed graph. Using this reduced representation, we compute instantaneous perturbations that switch the system between disparate spatiotemporal states occupying distant regions of the infinite-dimensional phase space. Overall, our results lay the groundwork for a systematic means of understanding and controlling active nematic flows in the moderate- to high-activity regime.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Theoretical Characterization of Correlated Redox Activity and Nanostructure in Hybrid Supercapacitors

Electrochemical energy storage devices such as supercapacitors, batteries, and fuel cells fundamentally rely on complex and correlated redox processes at electrode/electrolyte interfaces. Furthermore, the nanostructured morphology of high-surface area electrodes can significantly modulate this physics, and further complicates mechanistic understanding. Focusing on supercapacitor devices composed of carbon/polymer based electrodes and organic electrolytes, we will employ first-principles-based computer simulations to understand the coupling of these essential energy storage pathways occurring at the electrode/electrolyte interface. Of critical importance will be the development of theoretical methodologies to allow for the first-principles description of redox processes within electrochemical systems at fixed external voltage. Based on our hypothesis that redox activity and ion structuring is dramatically altered under nanoconfinement, we will then conduct a systematic study utilizing atomistic models of nanoporous carbon electrodes to understand the coupling of redox-activity, energy-storage, and nanostructuring for a variety of electrode morphologies.

25 ENERGY STORAGE↗
NASA NTRS1989

Reuse research plans at Langley Research Center

The reuse activities at Langley have centered on the development of the Eli System by SPS. The development of a computer systems design environment at Langley was described as a target application for the future Eli system. This environment combines software development tools with an architecture design and analysis tool. Specifically, a Computer-Aided Software Engineering (CASE) system, under development at Charles Stark Draper Laboratory for Langley, is being used to generate Ada code for use in architecture functional simulations using the Architecture Design and Assessment System (ADAS). The Eli system will be included in this tool set and will be used to organize and promote reuse of the functional simulation code modules.

Voigt, Susan J.↗
NASA NTRS1994

Building brains for bodies

We describe a project to capitalize on newly available levels of computational resources in order to understand human cognition. We will build an integrated physical system including vision, sound input and output, and dextrous manipulation, all controlled by a continuously operating large scale parallel MIMD computer. The resulting system will learn to 'think' by building on its bodily experiences to accomplish progressively more abstract tasks. Past experience suggests that in attempting to build such an integrated system we will have to fundamentally change the way artificial intelligence, cognitive science, linguistics, and philosophy think about the organization of intelligence. We expect to be able to better reconcile the theories that will be developed with current work in neuroscience.

Brooks, Rodney Allen↗
DOE OSTI2024

From Data to Knowledge: A Graph-Based Reliability Approach to Assess System Health

With the goal of maximizing plant reliability and availability, complex systems such as nuclear power plants continuously monitor and record the performance and the health status of many components, assets, and systems. Such data may take the form of online monitoring data, condition reports, and maintenance reports and it carries the potential to provide system engineers with insights into anomalous behaviors or degradation trends as well as the possible causes behind them and to predict their direct consequences. The analysis of such data poses however few challenges. While some of these challenges are technical in nature (i.e., data are often distributed over several physical servers or databases), others are conceptual in nature (i.e., data elements come in different formats, numeric or textual), and measured values have different scales (e.g., vibration spectra and oil temperature). This paper directly tackles these challenges, and it focuses on the integration of all these data elements in order to assist plant system engineers in analyzing component, assets, and systems performances and optimize maintenance activities. This is performed by 1) extracting knowledge from textual data via technical language processing methods, and 2) quantifying system, asset, and component health from numeric condition-based data. We rely on model-based system engineering (MBSE) models of systems and assets to identify their architecture and functional (i.e., cause and effect) relations. Numeric and textual data elements are then associated with an MBSE graph element, based on their nature. This bonding of MBSE models and data elements constitutes a first-of-its-kind knowledge graph of a nuclear power plants system, with data elements being organized in a structured manner that enables system engineers to identify cause-effect trends in data elements and carry out appropriate actions in response.

97 MATHEMATICS AND COMPUTING↗
NASA NTRS1993

Interoperability through standardization: Electronic mail, and X Window systems

Since the introduction of computing machines, there has been continual advances in computer and communication technologies and approaching limits. The user interface has evolved from a row of switches, character based interface using teletype terminals and then video terminals, to present day graphical user interface. It is expected that next significant advances will come in the availability of services, such as electronic mail and directory services, as the standards for applications are developed and in the 'easy to use' interfaces, such as Graphical User Interface for example Window and X Window, which are being standardized. Various proprietary electronic mail (email) systems are in use within organizations at each center of NASA. Each system provides email services to users within an organization, however the support for email services across organizations and across centers exists at centers to a varying degree and is often easy to use. A recent NASA email initiative is intended 'to provide a simple way to send email across organizational boundaries without disruption of installed base.' The initiative calls for integration of existing organizational email systems through gateways connected by a message switch, supporting X.400 and SMTP protocols, to create a NASA wide email system and for implementation of NASA wide email directory services based on OSI standard X.500. A brief overview of MSFC efforts as a part of this initiative are described. Window based graphical user interfaces make computers easy to use. X window protocol has been developed at Massachusetts Institute of Technology in 1984/1985 to provide uniform window based interface in a distributed computing environment with heterogenous computers. It has since become a standard supported by a number of major manufacturers. Z Windows systems, terminals and workstations, and X Window applications are becoming available. However impact of its use in the Local Area Network environment on the network traffic are not well understood. It is expected that the use of X Windows systems will increase at MSFC especially for Unix based systems. An overview of X Window protocol is presented and its impact on the network traffic is examined. It is proposed that an analytical model of X Window systems in the network environment be developed and validated through the use of measurements to generate application and user profiles.

Amin, Ashok T.↗
NASA NTRSDate not supplied

High Performance Access to Archival Data Stored in HDF4 and HDF5 on Cloud Object Stores Without Reformatting the Files

Cloud computing offers numerous advantages for users of extensive Earth science data collections. These benefits encompass direct online access to data files and granules from any location, scalable access supporting parallel computing workflows, and flexible computing tools enabling innovative experimentation with processing techniques. However, older archival file formats designed for distinct computing systems hinder efficient access to decade-long time-series data when compared to data stored in modern cloud-optimized formats like Web Object Stores (WOS), exemplified by Amazon Web Services’ Simple Storage Service (S3). We describe DMR++ (Dataset Metadata Response plus plus), a technology facilitating efficient access to HDF5 (Hierarchical Data Format, version 5) and HDF4 files stored on WOS systems without requiring data reformatting. DMR++ achieves performance comparable to technologies like Zarr while preserving the original file structure, a substantial benefit considering the vast quantity of archival files held by organizations such as NASA. Moreover, DMR++ typically outperforms cloud-optimized versions of HDF5. Essentially an XML (Extensible Markup Language) document usually stored alongside the described data, DMR++ can also be generated on-the-fly but is generally created during data staging to the WOS. Archival files that use HDF4/5 often store large arrays of numerical data. The data in these files is often compressed, typically reducing their size by a factor of four or more. To achieve efficient access to portions of those arrays, they are 'chunked' into smaller sub-arrays, each individually compressed. The chunk size is a compromise, where spinning disks can efficiently access data in smaller chunks while S3 favors larger chunks. A simple optimization of aggregating smaller chunks that are stored adjacently, transferring them in a single access and then individually decompressing them will improve performance. NASA data pose an additional challenge: special Application Programmer Interface (API) libraries are often needed to compute some variables. These libraries are incompatible with WOS environments. Our solution involves storing computed values in the DMR++ document or a companion file, making them accessible like other variables and eliminating the need for specialized APIs. We outline specific optimizations for both satellite grid and swath data stored in HDF4-EOS2 (Earth Observing System).

James Gallagher↗
DOE OSTI2023

December 2022 NS&T Highlights

Highlights for the Nuclear Science and Technology organization for the month of December 2022.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
NASA NTRS2009

Effective Materials Property Information Management for the 21st Century

This paper discusses key principles for the development of materials property information management software systems. There are growing needs for automated materials information management in various organizations. In part these are fueled by the demands for higher efficiency in material testing, product design and engineering analysis. But equally important, organizations are being driven by the need for consistency, quality and traceability of data, as well as control of access to sensitive information such as proprietary data. Further, the use of increasingly sophisticated nonlinear, anisotropic and multi-scale engineering analyses requires both processing of large volumes of test data for development of constitutive models and complex materials data input for Computer-Aided Engineering (CAE) software. And finally, the globalization of economy often generates great needs for sharing a single "gold source" of materials information between members of global engineering teams in extended supply chains. Fortunately, material property management systems have kept pace with the growing user demands and evolved to versatile data management systems that can be customized to specific user needs. The more sophisticated of these provide facilities for: (i) data management functions such as access, version, and quality controls; (ii) a wide range of data import, export and analysis capabilities; (iii) data "pedigree" traceability mechanisms; (iv) data searching, reporting and viewing tools; and (v) access to the information via a wide range of interfaces. In this paper the important requirements for advanced material data management systems, future challenges and opportunities such as automated error checking, data quality characterization, identification of gaps in datasets, as well as functionalities and business models to fuel database growth and maintenance are discussed.

Ren, Weiju↗
NASA NTRS1985

Office automation: The administrative window into the integrated DBMS

In parallel to the evolution of Management Information Systems from simple data files to complex data bases, the stand-alone computer systems have been migrating toward fully integrated systems serving the work force. The next major productivity gain may very well be to make these highly sophisticated working level Data Base Management Systems (DMBS) serve all levels of management with reports of varying levels of detail. Most attempts by the DBMS development organization to provide useful information to management seem to bog down in the quagmire of competing working level requirements. Most large DBMS development organizations possess three to five year backlogs. Perhaps Office Automation is the vehicle that brings to pass the Management Information System that really serves management. A good office automation system manned by a team of facilitators seeking opportunities to serve end-users could go a long way toward defining a DBMS that serves management. This paper will briefly discuss the problems of the DBMS organization, alternative approaches to solving some of the major problems, a debate about problems that may have no solution, and finally how office automation fits into the development of the Manager's Management Information System.

Brock, G. H.↗
NASA NTRS1994

Automated mainframe data collection in a network environment

The progress and direction of the computer industry have resulted in widespread use of dissimilar and incompatible mainframe data systems. Data collection from these multiple systems is a labor intensive task. In the past, data collection had been restricted to the efforts of personnel specially trained on each system. Information is one of the most important resources an organizations has. Any improvement in an organization's ability to access and manage that information provides a competitive advantage. This problem of data collection is compounded at NASA sites by multi-center and contractor operations. The Centralized Automated Data Retrieval System (CADRS) is designed to provide a common interface that would permit data access, query, and retrieval from multiple contractor and NASA systems. The methods developed for CADRS have a strong commercial potential in that they would be applicable for any industry that needs inter-department, inter-company, or inter-agency data communications. The widespread use of multi-system data networks, that combine older legacy systems with newer decentralized networks, has made data retrieval a critical problem for information dependent industries. Implementing the technology discussed in this paper would reduce operational expense and improve data collection on these composite data systems.

Gross, David L.↗
NASA NTRS2003

Effective Team Support: From Modeling to Software Agents

The purpose of this research contract was to perform multidisciplinary research between CMU psychologists, computer scientists and engineers and NASA researchers to design a next generation collaborative system to support a team of human experts and intelligent agents. To achieve robust performance enhancement of such a system, we had proposed to perform task and cognitive modeling to thoroughly understand the impact technology makes on the organization and on key individual personnel. Guided by cognitively-inspired requirements, we would then develop software agents that support the human team in decision making, information filtering, information distribution and integration to enhance team situational awareness. During the period covered by this final report, we made substantial progress in modeling infrastructure and task infrastructure. Work is continuing under a different contract to complete empirical data collection, cognitive modeling, and the building of software agents to support the teams task.

Remington, Roger W.↗