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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 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1990

Research into display sharing techniques for distributed computing environments

The X-based Display Sharing solution for distributed computing environments is described. The Display Sharing prototype includes the base functionality for telecast and display copy requirements. Since the prototype implementation is modular and the system design provided flexibility for the Mission Control Center Upgrade (MCCU) operational consideration, the prototype implementation can be the baseline for a production Display Sharing implementation. To facilitate the process the following discussions are presented: Theory of operation; System of architecture; Using the prototype; Software description; Research tools; Prototype evaluation; and Outstanding issues. The prototype is based on the concept of a dedicated central host performing the majority of the Display Sharing processing, allowing minimal impact on each individual workstation. Each workstation participating in Display Sharing hosts programs to facilitate the user's access to Display Sharing as host machine.

Hugg, Steven B.↗
NASA NTRS1991

Design of the SHARE II monogroove heat pipe

The SHARE II experiment will fly on STS-43, scheduled for mid-1991. The experiment consists of two prototypical heat pipe radiator elements, one of which is supplied by Grumman Aerospace Corp. The heat pipes are designed to overcome the shortcomings of the SHARE experiment, which flew on STS-29 in March 1989 and was only partially successful. This paper reviews the SHARE experiment and the results of its flight test. The design solutions considered for use in the Grumman SHARE II heat pipe are discussed. A description of the reduced gravity testing of the design solutions is provided, as is a discussion of the final SHARE II design. In addition, the 1-g acceptance testing and thermal/vacuum certification testing of the Grumman SHARE II flight article is described.

Brown, Richard↗
NASA NTRS1992

Split torque transmission load sharing

Split torque transmissions are attractive alternatives to conventional planetary designs for helicopter transmissions. The split torque designs can offer lighter weight and fewer parts but have not been used extensively for lack of experience, especially with obtaining proper load sharing. Two split torque designs that use different load sharing methods have been studied. Precise indexing and alignment of the geartrain to produce acceptable load sharing has been demonstrated. An elastomeric torque splitter that has large torsional compliance and damping produces even better load sharing while reducing dynamic transmission error and noise. However, the elastomeric torque splitter as now configured is not capable over the full range of operating conditions of a fielded system. A thrust balancing load sharing device was evaluated. Friction forces that oppose the motion of the balance mechanism are significant. A static analysis suggests increasing the helix angle of the input pinion of the thrust balancing design. Also, dynamic analysis of this design predicts good load sharing and significant torsional response to accumulative pitch errors of the gears.

Krantz, T. L.↗
NASA NTRS1996

Theory and ontology for sharing temporal knowledge

Using current technology, the sharing or re-using of knowledge-bases is very difficult, if not impossible. ARPA has correctly recognized the problem and funded a knowledge sharing initiative. One of the outcomes of this project is a formal language called Knowledge Interchange Format (KIF) for representing knowledge that could be translated into other languages. Capturing and representing design knowledge and reasoning with them have become very important for NASA who is a pioneer of innovative design of unique products. For upgrading an existing design for changing technology, needs, or requirements, it is essential to understand the design rationale, design choices, options and other relevant information associated with the design. Capturing such information and presenting them in the appropriate form are part of the ongoing Design Knowledge Capture project of NASA. The behavior of an object and various other aspects related to time are captured by the appropriate temporal knowledge. The captured design knowledge will be represented in such a way that various groups of NASA who are interested in various aspects of the design cycle should be able to access and use the design knowledge effectively. To facilitate knowledge sharing among these groups, one has to develop a very well defined ontology. Ontology is a specification of conceptualization. In the literature several specific domains were studied and some well defined ontologies were developed for such domains. However, very little, or no work has been done in the area of representing temporal knowledge to facilitate sharing. During the ASEE summer program, I have investigated several temporal models and have proposed a theory for time that is flexible to accommodate the time elements, such as, points and intervals, and is capable of handling the qualitative and quantitative temporal constraints. I have also proposed a primitive temporal ontology using which other relevant temporal ontologies can be built. I have investigated various issues of sharing knowledge and have proposed a formal framework for modeling the concept of knowledge sharing. This work may be implemented and tested in the software environment supplied by Knowledge Based System, Inc.

Loganantharaj, Rasiah↗
NASA NTRS2010

Professionals and Emerging Scientists Sharing Science

The Year of the Solar System (YSS) celebration begins in the fall of 2010. As YSS provides a means in which NASA can inspire members of the public about exciting missions to other worlds in our solar system, it is important to remember these missions are about the science being conducted and new discoveries being made. As part of the Year of the Solar System, Astromaterials Research and Exploration Science (ARES) Education, at the NASA Johnson Space Center, will infuse the great YSS celebration within the Expedition Earth and Beyond Program. Expedition Earth and Beyond (EEAB) is an authentic research program for students in grades 5-14 and is a component of ARES Education. Students involved in EEAB have the opportunity to conduct and share their research about Earth and/or planetary comparisons. ARES Education will help celebrate this exciting Year of the Solar System by inviting scientists to share their science. Throughout YSS, each month will highlight a topic related to exploring our solar system. Additionally, special mission events will be highlighted to increase awareness of the exciting missions and exploration milestones. To bring this excitement to classrooms across the nation, the Expedition Earth and Beyond Program and ARES Education will host classroom connection events in which scientists will have an opportunity to share discoveries being made through scientific research that relate to the YSS topic of the month. These interactive presentations will immerse students in some of the realities of exploration and potentially inspire them to conduct their own investigations. Additionally, scientists will share their own story of how they were inspired to pursue a STEM-related career that got them involved in exploration. These career highlights will allow students to understand and relate to the different avenues that scientists have taken to get where they are today. To bring the sharing of science full circle, student groups who conduct research by participating in Expedition Earth and Beyond, will also have the opportunity to virtually share their research. These virtual team presentations will allow these emerging scientists to celebrate their own exploration, and in doing so, contribute to the excitement of the Year of the Solar System. As the public joins NASA in the celebration of YSS, students across the nation will not only be excited by the science and discoveries being made, but will prime themselves with experience to perhaps someday become the new leaders in science, discovery, and NASA.

Graff, P. V.↗
NASA NTRS2015

Parameter Impact on Sharing Studies Between UAS CNPC Satellite Transmitters and Terrestrial Systems

In order to provide a control and non-payload communication (CNPC) link for civil-use unmanned aircraft systems (UAS) when operating in beyond-line-of-sight (BLOS) conditions, satellite communication links are generally required. The International Civil Aviation Organization (ICAO) has determined that the CNPC link must operate over protected aviation safety spectrum allocations. Although a suitable allocation exists in the 5030-5091 MHz band, no satellites provide operations in this band and none are currently planned. In order to avoid a very lengthy delay in the deployment of UAS in BLOS conditions, it has been proposed to use existing satellites operating in the Fixed Satellite Service (FSS), of which many operate in several spectrum bands. Regulatory actions by the International Telecommunications Union (ITU) are needed to enable such a use on an international basis, and indeed Agenda Item (AI) 1.5 for the 2015 World Radiocommunication Conference (WRC) was established to decide on the enactment of possible regulatory provisions. As part of the preparation for AI 1.5, studies on the sharing FSS bands between existing services and CNPC for UAS are being contributed by NASA and others. These studies evaluate the potential impact of satellite CNPC transmitters operating from UAS on other in-band services, and on the potential impact of other in-band services on satellite CNPC receivers operating on UAS platforms. Such studies are made more complex by the inclusion of what are essentially moving FSS earth stations, compared to typical sharing studies between fixed elements. Hence, the process of determining the appropriate technical parameters for the studies meets with difficulty. In order to enable a sharing study to be completed in a less-than-infinite amount of time, the number of parameters exercised must be greatly limited. Therefore, understanding the impact of various parameter choices is accomplished through selectivity analyses. In the case of sharing studies for AI 1.5, identification of worst-case parameters allows the studies to be focused on worst-case scenarios with assurance that other parameter combinations will yield comparatively better results and therefore do not need to be fully analyzed. In this paper, the results of such sensitivity analyses are presented for the case of sharing between UAS CNPC satellite transmitters and terrestrial receivers using the Fixed Service (FS) operating in the same bands, and the implications of these analyses on sharing study results.

air traffic control↗
NASA NTRS2022

Diesel Passenger Vehicle Shares Influenced Covid-19 Changes in Urban Nitrogen Dioxide Pollution

Diesel-powered vehicles emit several times more nitrogen oxides than comparable gasoline-powered vehicles, leading to ambient nitrogen dioxide (NO2) pollution and adverse health impacts. The COVID-19 pandemic and ensuing changes in emissions provide a natural experiment to test whether NO2 reductions have been starker in regions of Europe with larger diesel passenger vehicle shares. Here we use a semi-empirical approach that combines in-situ NO2 observations from urban areas and an atmospheric composition model within a machine learning algorithm to estimate business-as-usual NO2 during the first wave of the COVID-19 pandemic in 2020. These estimates account for the moderating influences of meteorology, chemistry, and traffic. Comparing the observed NO2 concentrations against business-as-usual estimates indicates that diesel passenger vehicle shares played a major role in the magnitude of NO2 reductions. European cities with the five largest shares of diesel passenger vehicles experienced NO2 reductions ∼ 2.5 times larger than cities with the five smallest diesel shares. Extending our methods to a cohort of non-European cities reveals that NO2 reductions in these cities were generally smaller than reductions in European cities, which was expected given their small diesel shares. We identify potential factors such as the deterioration of engine controls associated with older diesel vehicles to explain spread in the relationship between cities’ shares of diesel vehicles and changes in NO2 during the pandemic. Our results provide a glimpse of potential NO2 reductions that could accompany future deliberate efforts to phase out or remove passenger vehicles from cities.

Nitrogen Dioxide↗
DOE OSTI2025

Double-null power-sharing dynamics in MAST-U

Maintaining an effective double-null (DN) configuration is expected to be challenging in reactor-scale tokamak devices. As divertor power-sharing is closely linked to the magnetic topology, even minor variations can lead to fast power-sharing fluctuations which exacerbate the already daunting exhaust challenge. While the static aspects of DN power-sharing have been extensively studied across various devices, this paper presents the first detailed investigation of its dynamic behaviour. We employ dedicated H-mode experiments in MAST-U, in Super-X divertor configuration, featuring perturbation frequencies up to 200 Hz. Our results clearly show no significant dynamic damping of the power-sharing within this frequency range: the divertor responds equally to both fast and slow perturbations. Moreover, the dynamic response also aligns with quasi-static results from slow ramps, implying that static power-sharing models remain valid even for fast fluctuations. Occasionally, some deviations from the otherwise mainly linear behaviour are observed, alongside notable scatter and asymmetries between upwards and downwards trajectories. These observations are likely linked to changes in core conditions, though the underlying mechanisms remain unclear and require further study.

divertor↗
DOE OSTI2024

Solar and Wind Forecast Error Reserve Sharing in a Multi-Utility Region

As electricity systems transition to higher levels of solar and wind generation, electric system operators will likely need to hold additional reserves to manage solar and wind forecast error. Because solar and wind forecast errors tend to be weakly correlated across space, system operators can reduce their reserve requirements by sharing reserves. This paper examines the benefits of forecast error reserve sharing among balancing areas in the Southeastern United States, in scenarios in which solar and wind generation ranges from 34% to 65% of total generation. It finds that day-ahead forecast error reserve requirements increase linearly with growth in solar and wind generation capacity (6%-10% of total capacity), but that reserve sharing can significantly reduce these requirements (by 6%-29%). It finds that, in economic terms, the value of forecast error reserve sharing ($\$$0.09-$\$$1.24 billion per year, $\$$0.12-$\$$1.68/MWh of load across scenarios) tends to decline with higher levels of solar and wind generation, due to lower reserve and energy prices. Even with declines in reserve prices, forecast error reserve sharing can still provide substantial value, though with higher levels of solar, wind, and electricity storage this value is increasingly tied to avoiding scarcity prices.

14 SOLAR ENERGY↗
NASA NTRS1985

Can pilots time-share better than non-pilots?

The time-sharing ability of 12 male pilots and 12 male college students ranging in age from 18-36 are evaluated and compared. The subjects performed five pairs of dual tasks with varying degrees of structural similarity; the test procedures are described. The time-sharing efficiency and resource allocation optimality of the subjects are analyzed. The data reveal that the pilots and students display similar time-sharing performance; the degree of time-sharing efficiency decreases and resource allocation optimality increases with an increasing degree of structural similarity between the time-shared tasks.

Tsang, P. S.↗
NASA NTRS1989

Recoverable distributed shared virtual memory - Memory coherence and storage structures

This paper examines the problem of implementing rollback recovery in multicomputer distributed shared virtual memory environments, in which the shared memory is implemented in software and exists only virtually. A user-transparent checkpointing recovery scheme and new twin-page disk storage management are presented to implement a recoverable distributed shared virtual memory. The checkpointing scheme is integrated with the shared virtual memory management. The twin-page disk approach allows incremental checkpointing without an explicit undo at the time of recovery. A single consistent checkpoint state is maintained on stable disk storage. The recoverable distributed shared virtual memory allows the system to restart computation from a previous checkpoint due to a processor failure without a global restart.

Wu, Kun-Lung↗
NASA NTRS1990

Recoverable distributed shared virtual memory

The problem of rollback recovery in distributed shared virtual environments, in which the shared memory is implemented in software in a loosely coupled distributed multicomputer system, is examined. A user-transparent checkpointing recovery scheme and a new twin-page disk storage management technique are presented for implementing recoverable distributed shared virtual memory. The checkpointing scheme can be integrated with the memory coherence protocol for managing the shared virtual memory. The twin-page disk design allows checkpointing to proceed in an incremental fashion without an explicit undo at the time of recovery. The recoverable distributed shared virtual memory allows the system to restart computation from a checkpoint without a global restart.

Wu, Kun-Lung↗
NASA NTRS1994

Shared virtual environments for aerospace training

Virtual environments have the potential to significantly enhance the training of NASA astronauts and ground-based personnel for a variety of activities. A critical requirement is the need to share virtual environments, in real or near real time, between remote sites. It has been hypothesized that the training of international astronaut crews could be done more cheaply and effectively by utilizing such shared virtual environments in the early stages of mission preparation. The Software Technology Branch at NASA's Johnson Space Center has developed the capability for multiple users to simultaneously share the same virtual environment. Each user generates the graphics needed to create the virtual environment. All changes of object position and state are communicated to all users so that each virtual environment maintains its 'currency.' Examples of these shared environments will be discussed and plans for the utilization of the Department of Defense's Distributed Interactive Simulation (DIS) protocols for shared virtual environments will be presented. Finally, the impact of this technology on training and education in general will be explored.

Loftin, R. Bowen↗
NASA NTRS2006

Heat Load Sharing in a Loop Heat Pipe with Multiple Evaporators and Multiple Condensers

This paper describes the heat load sharing function among multiple parallel evaporators in a loop heat pipe (LHP). Each evaporator can be attached to an instrument. In the normal mode of operation, each evaporator will cool the corresponding instrument by absorbing the waste heat. When an instrument is turned off, the attached evaporator can keep it warm by receiving heat from other evaporators serving the operating instruments. This is referred to as heat load sharing. The fact that the wicks in the powered evaporators will develop capillary pressure to force the vapor that is being generated to flow to cold locations where the pressure is lower leads to the conclusion that heat load sharing is an inherent function of an LHP with multiple evaporators. This paper presents a theoretical basis of the LHP heat load sharing operation, and experimental results from ground tests of an LHP with two evaporator and two condensers. Factors that affect the amount of heat being shared are also discussed.

Ku, Jentung↗
NASA NTRS2009

Internet Protocol Display Sharing Solution for Mission Control Center Video System

With the advent of broadcast television as a constant source of information throughout the NASA manned space flight Mission Control Center (MCC) at the Johnson Space Center (JSC), the current Video Transport System (VTS) characteristics provides the ability to visually enhance real-time applications as a broadcast channel that decision making flight controllers come to rely on, but can be difficult to maintain and costly. The Operations Technology Facility (OTF) of the Mission Operations Facility Division (MOFD) has been tasked to provide insight to new innovative technological solutions for the MCC environment focusing on alternative architectures for a VTS. New technology will be provided to enable sharing of all imagery from one specific computer display, better known as Display Sharing (DS), to other computer displays and display systems such as; large projector systems, flight control rooms, and back supporting rooms throughout the facilities and other offsite centers using IP networks. It has been stated that Internet Protocol (IP) applications are easily readied to substitute for the current visual architecture, but quality and speed may need to be forfeited for reducing cost and maintainability. Although the IP infrastructure can support many technologies, the simple task of sharing ones computer display can be rather clumsy and difficult to configure and manage to the many operators and products. The DS process shall invest in collectively automating the sharing of images while focusing on such characteristics as; managing bandwidth, encrypting security measures, synchronizing disconnections from loss of signal / loss of acquisitions, performance latency, and provide functions like, scalability, multi-sharing, ease of initial integration / sustained configuration, integration with video adjustments packages, collaborative tools, host / recipient controllability, and the utmost paramount priority, an enterprise solution that provides ownership to the whole process, while maintaining the integrity of the latest technological displayed image devices. This study will provide insights to the many possibilities that can be filtered down to a harmoniously responsive product that can be used in today's MCC environment.

Brown, Michael A.↗
NASA NTRS2004

Coordinating Shared Activities

Shared Activity Coordination (ShAC) is a computer program for planning and scheduling the activities of an autonomous team of interacting spacecraft and exploratory robots. ShAC could also be adapted to such terrestrial uses as helping multiple factory managers work toward competing goals while sharing such common resources as floor space, raw materials, and transports. ShAC iteratively invokes the Continuous Activity Scheduling Planning Execution and Replanning (CASPER) program to replan and propagate changes to other planning programs in an effort to resolve conflicts. A domain-expert specifies which activities and parameters thereof are shared and reports the expected conditions and effects of these activities on the environment. By specifying these conditions and effects differently for each planning program, the domain-expert subprogram defines roles that each spacecraft plays in a coordinated activity. The domain-expert subprogram also specifies which planning program has scheduling control over each shared activity. ShAC enables sharing of information, consensus over the scheduling of collaborative activities, and distributed conflict resolution. As the other planning programs incorporate new goals and alter their schedules in the changing environment, ShAC continually coordinates to respond to unexpected events.

Clement, Bradley↗
NASA NTRS2012

Secure Peer-to-Peer Networks for Scientific Information Sharing

The most common means of remote scientific collaboration today includes the trio of e-mail for electronic communication, FTP for file sharing, and personalized Web sites for dissemination of papers and research results. With the growth of broadband Internet, there has been a desire to share large files (movies, files, scientific data files) over the Internet. Email has limits on the size of files that can be attached and transmitted. FTP is often used to share large files, but this requires the user to set up an FTP site for which it is hard to set group privileges, it is not straightforward for everyone, and the content is not searchable. Peer-to-peer technology (P2P), which has been overwhelmingly successful in popular content distribution, is the basis for development of a scientific collaboratory called Scientific Peer Network (SciPerNet). This technology combines social networking with P2P file sharing. SciPerNet will be a standalone application, written in Java and Swing, thus insuring portability to a number of different platforms. Some of the features include user authentication, search capability, seamless integration with a data center, the ability to create groups and social networks, and on-line chat. In contrast to P2P networks such as Gnutella, Bit Torrent, and others, SciPerNet incorporates three design elements that are critical to application of P2P for scientific purposes: User authentication, Data integrity validation, Reliable searching SciPerNet also provides a complementary solution to virtual observatories by enabling distributed collaboration and sharing of downloaded and/or processed data among scientists. This will, in turn, increase scientific returns from NASA missions. As such, SciPerNet can serve a two-fold purpose for NASA: a cost-savings software as well as a productivity tool for scientists working with data from NASA missions.

Karimabadi, Homa↗
NASA NTRS2014

Multilateral Biomedical Data Sharing in the One-year Joint US-Russian Mission on the International Space Station

The One Year Mission (1YM) by two astronauts on the International Space Station (ISS), starting in March 2015, offers a unique opportunity to expand multilateral collaboration by sharing data and resources among the partner agencies in preparation for planned space exploration missions beyond low Earth orbit. Agreements and protocols will be established for the collection, distribution, analysis and reporting of both research and clinical data. Data will be shared between the agencies sponsoring the investigators, and between the research and clinical medicine communities where common interests are identified. The assignment of only two astronauts, one Russian and the other American, to the 1YM necessitated creativity in bilateral efforts to maximize the biomedical return from the opportunity. Addition of Canadian, European and Japanese investigations make the effort even more integrative. There will be three types of investigations: joint, cross‐participation and data‐exchange. The joint investigations have US and Russian coprincipal investigators, and the data acquired will be their common responsibility. The other two types must develop data sharing agreements and processes specific to their needs. A multilateral panel of ISS partner space agencies will develop policies for international exchange of scientific information to meet their science objectives and priorities. They will promote archiving of space flight data and will inform each other and the scientific community at large about the results obtained from space life sciences studies. Integration tasks for the 1YM are based on current experience from the ISS and previous efforts on the Russian space station Mir. Closer coordination between international partners requires more common approaches to remove barriers to multilateral resource utilization on the ISS. Greater integration in implementation should increase utilization efficiency to benefit all participants in spaceflight human research. This presentation will describe the overarching principles for multilateral data collection, analysis and sharing and for data security for medical and research data shared between ISS partners prior to release in public forums.

Charles, John B.↗