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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 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRS1997

NASA/DOD Aerospace Knowledge Diffusion Research Project. Paper 62: The Influence of Knowledge Diffusion on Aeronautics Innovation: The Research, Development, and Production of Large Commercial Aircraft in France, Germany, and the United Kingdom

This paper focuses on how European public policies-individually and collectively - influence the diffusion of knowledge and technology. It begins with an overview of the roles played historically and currently by European governments in the research, development and production (RD&P) of large commercial aircraft (LCA). The analytical framework brings together literature from global political economy, comparative politics, business management, and science and technology policy studies. It distinguishes between the production of knowledge, on the one hand, and the dissemination of knowledge, on the other. France, Germany, and the United Kingdom serve as the analytical cases. The paper concludes with a call for additional research in this area, some tentative lessons learned, and a discussion of the consequences of national strategies and policies for the diffusion of knowledge and technology in an era of globalization.

Pinelli, Thomas E.↗
NASA NTRS1997

NASA/DOD Aerospace Knowledge Diffusion Research Project. Paper 62: The Influence of Knowledge Diffusion on Aeronautics Innovation: The Research, Development, and Production of Large Commercial Aircraft in France, Germany, and the United Kingdom

This paper focuses on how European public policies-individually and collectively - influence the diffusion of knowledge and technology. It begins with an overview of the roles played historically and currently by European governments in the Research, Development and Production (RD&P) of Large Commercial Aircraft (LCA). The analytical framework brings together literature from global political economy, comparative politics, business management, and science and technology policy studies. It distinguishes between the production of knowledge, on the one hand, and the dissemination of knowledge, on the other. France, Germany, and the United Kingdom serve as the analytical cases. The paper concludes with a call for additional research in this area, some tentative lessons learned, and a discussion of the consequences of national strategies and policies for the diffusion of knowledge and technology in an era of globalizaton.

Golich, Vicki L.↗
NASA NTRS2020

Performance of NOAA-20 VIIRS Solar Diffuser and Solar Diffuser Stability Monitor

Visible Infrared Imaging Radiometer Suite (VIIRS) radiometrically calibrates its reflective solar bands (RSBs) primarily through a sunlit onboard solar diffuser (SD). The sunlit SD provides a known radiance under the condition that the absolute product of the SD screen transmittance and the bidirectional reflectance distribution function (BRDF) along the SD-to-telescope direction is accurately known. The BRDF changes due to solar exposure. The change, referred to as the H-factor, is monitored by the onboard SD stability monitor (SDSM). The accuracy of the retrieved H-factor propagates to the retrieved F-factor which corrects the scene spectral radiance. High accuracy of the retrieved H-factor relies on high accuracies in the SDSM screen relative effective transmittance and the relative product of the SD screen effective transmittance and the BRDF at the mission start, and a high SDSM detector signal-to-noise ratio (SNR). This article briefly reviews the algorithms used for the NOAA-20 (N20) VIIRS RSB on-orbit radiometric calibration. Additionally, we show the performance of the N20 VIIRS SDSM, giving the SDSM detector SNRs and the SDSM detector gain temporal changes. We develop a model for the SNRs. The model shows that the decreased SNRs in time are due to the detector gain decreases. We also show the N20 VIIRS SD on-orbit performance, measured by the retrieved H-factor and the estimated standard deviation of its error. The H-factor for the telescope view is obtained from the H-factor for the SDSM view, multiplied by an H-factor angular dependence term. We use an innovative method to determine the angular dependence, using the dependence obtained for the Suomi National Polar-orbiting Partnership (SNPP) VIIRS.

VIIRS↗
DOE OSTI2022

Diffusion Monte Carlo approaches for studying nuclear quantum effects in fluxional molecules

Abstract Diffusion quantum Monte Carlo (DMC) provides a powerful approach for obtaining the ground state energy and wave function of molecules, ions, and molecular clusters. The approach is uniquely well suited for studies of fluxional molecules, which undergo large amplitude vibrational motions even in their ground state. In contrast to the electronic structure problem, where the wave function must be antisymmetric with respect to exchange of any pair of electrons, the wave function for the ground vibrational state is nodeless. This greatly simplifies the application of DMC for vibrational problems. Because there is not a single potential function that can be used to describe the intramolecular and intermolecular interactions in all molecular systems, most methods that are used to describe nuclear quantum effects rely on a carefully chosen zero‐order description of the molecular vibrations. In contrast, DMC calculations can be performed in Cartesian coordinates, making the DMC algorithm easily transferable between different chemical systems. In this contribution, the theory that underlies DMC will be discussed along with important considerations for performing DMC calculations. Extensions for evaluating vibrationally excited states and molecular properties are also discussed. Insights that can be obtained from DMC calculations are illustrated in the context of the protonated water clusters. This article is categorized under: Molecular and Statistical Mechanics > Molecular Dynamics and Monte‐Carlo Methods Theoretical and Physical Chemistry > Spectroscopy

Chemistry↗
DOE OSTI2022

Molecular Simulations Probing the Adsorption and Diffusion of Ammonia, Nitrogen, Hydrogen, and Their Mixtures in Bulk MFI Zeolite and MFI Nanosheets at High Temperature and Pressure

Recent advances in the synthesis of MFI zeolite nanosheets have led to highly selective membranes that are promising candidates for small-scale ammonia separation from ammonia/nitrogen/hydrogen mixtures in distributed green ammonia production plants. Using force-field-based molecular simulations, we evaluate the performance of bulk all-silica MFI zeolite and a 3 nm thick all-silica MFI nanosheet for ammonia/nitrogen/hydrogen separations at moderate temperature and pressure conditions (T = 373 K, p = 5 bar) as well as conditions relevant for a membrane-based reactor–separator process (T = 523 or 623 K, p = 80 bar). Isobaric–isothermal Gibbs ensemble Monte Carlo (GEMC) simulations were carried out to understand the selective adsorption behavior for these mixtures. Molecular dynamics simulations in the canonical ensemble were performed to examine the transport behavior of ammonia in a mixture with nitrogen or hydrogen at loadings obtained from the GEMC simulations. Our results show that both bulk MFI and the nanosheet with explicit surface silanols are highly selective toward ammonia adsorption, but the adsorption selectivity decreases by factors of 4 and 10 for ammonia/nitrogen and ammonia/hydrogen mixtures as the temperature is increased from 373 to 623 K. Conversely, the diffusion selectivities toward ammonia are more favorable at process-relevant temperatures and for the MFI nanosheet. Here, at T = 523 K and p = 80 bar, our simulations predict overall separation factors of 3.8 ± 0.2 and 4.5 ± 0.3 for ammonia/nitrogen and ammonia/hydrogen mixtures, respectively, in the bulk MFI zeolite, and separation factors of 8.6 ± 0.4 and 12.5 ± 0.8, respectively, for the MFI nanosheet.

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

Integrated Reference Electrodes in Anion-Exchange-Membrane Electrolyzers: Impact of Stainless-Steel Gas-Diffusion Layers and Internal Mechanical Pressure

Alkaline-membrane electrolyzers operating in pure water might provide scalable low-cost H 2 production but currently lag in performance and durability compared to commercial technologies. Typically, membrane–electrode assemblies (MEAs) are optimized in electrolyzers by changing one parameter at a time and assessing the resulting system performance via two-electrode polarization and impedance measurements. These approaches are limited in their ability to assign performance changes and durability to specific electrodes or processes. We integrate a reference electrode with the MEA to separate anode and cathode responses in both polarization and impedance measurements. Here we illustrate the power of the approach by showing how the fiber diameter of stainless-steel gas-diffusion layers (GDLs) affects performance solely at the anode, while changing the thickness of the cathode GDL simultaneously affects the performance of the anode and cathode due to changes in internal pressure from mechanical compression. This finding was obscured in conventional two-electrode measurements. The work thus guides both high-performance alkaline-membrane water-electrolyzer development and illustrates a useful strategy to study structure–activity relationships in the MEA.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1990

NASA/DOD Aerospace Knowledge Diffusion Research Project. Paper 5: Aerospace librarians and technical information specialists as information intermediaries: A report of phase 2 activities of the NASA/DOD Aerospace Knowledge Diffusion Research Project

The flow of U.S. government-funded and foreign scientific and technical information (STI) through libraries and related facilities to users in government and industry is examined, summarizing preliminary results of Phase 2 of the NASA/DOD Aerospace Knowledge Diffusion Research Project (NAKDRP). The design and objectives of NAKDRP are reviewed; the NAKDRP model of STI transfer among producers, STI intermediaries, surrogates (technical report repositories or clearinghouses), and users is explained and illustrated with diagrams; and particular attention is given to the organization and operation of aerospace libraries. In a survey of North American libraries it was found that 25-30 percent of libraries regularly receive technical reports from ESA and the UK; the corresponding figures for Germany and for France, Sweden, and Japan are 18 and 5 percent, respectively. Also included is a series of bar graphs showing the librarians' assessments of the quality and use of NASA Technical Reports.

Pinelli, Thomas E.↗
NASA NTRS1991

NASA/DOD Aerospace Knowledge Diffusion Research Project. Paper 16: Aerospace knowledge diffusion research

The project is a cooperative US effort between NASA, DoD, and Indiana University. This research was endorsed by the AGARD Technical Information Panel and the American Institute of Aeronautics and Astronautics (AIAA) Technical Information Committee. The four-phase inquiry focuses on scientific and technical information (STI) as knowledge, the channels through which this knowledge is communicated, and the members of the social system associated with and involved in diffusing this knowledge throughout the aerospace community. The project is based on two premises: (1) although STI is essential to innovation, STI by itself does not ensure innovation; and (2) utilizing existing STI or creating new STI, does often facilitate technological innovation. The topics covered include the following: information-seeking habits, knowledge transfer, academic sector, non-US organizations, present status, comparative study, and timetable.

Pinelli, Thomas E.↗
NASA NTRS1992

NASA/DOD Aerospace Knowledge Diffusion Research Project. Paper 27: Knowledge diffusion and US government technology policy: Issues and opportunities for sci/tech librarians

Federal involvement in simulating economic growth through the development and application of technology policy is currently the subject of serious debate. A recession and the recognition that an internationally competitive economy is a prerequisite for the attainment of national goals have fostered a number of technology policy initiatives aimed at improving the economic competitiveness of American industry. This paper suggests that the successful implementation of U.S. technology policy will require the adoption of a knowledge diffusion model, the development of user oriented information products and services, and a more 'activist' approach on the part of sci/tech librarians in the provision of scientific and technical information (STI). These changes will have a dramatic impact on the sci/tech library of the future and the preparation of sci/tech librarians.

Pinelli, Thomas E.↗
NASA NTRS1992

A comparison between protein crystals grown with vapor diffusion methods in microgravity and protein crystals using a gel liquid-liquid diffusion ground-based method

Crystals of human serum albumin have been successfully grown in a variety of gels using crystallization conditions otherwise equivalent to those utilized in the popular hanging-drop vapor-equilibrium method. Preliminary comparisons of gel grown crystals with crystals grown by the vapor diffusion method via both ground-based and microgravity methods indicate that crystals superior in size and quality may be grown by limiting solutal convection. Preliminary X-ray diffraction statistics are presented.

Miller, Teresa Y.↗
NASA NTRS1992

Quasi-linear velocity space diffusion of heavy cometary pickup ions on bispherical diffusion characteristics

We consider an ion transport equation describing the source, convection, adiabatic acceleration, and quasi-linear velocity diffusion of cometary pickup ions. The equation is solved numerically along solar wind plasma flow lines for the environment of Comet Halley, to obtain distributions at positions on the Giotto spacecraft trajectory which may be compared with observations. We obtain full two-dimensional (pitch angle and velocity) numerical distributions which show pitch angle scattering about the wave scattering centers at +/- V(A), where V(A) is the Alfven wave speed in the solar wind frame. Peak ion phase-space densities approximately follow the bispherical shell geometry. The energy distributions F(v) agree well with Giotto observations at lower v, but in the high-energy tail there is evidence possibly for the first-order Fermi acceleration mechanism taking place in the Comet Halley foreshock region.

Huddleston, D. E.↗
NASA NTRS1992

NASA/DoD Aerospace Knowledge Diffusion Research Project. XXVII - Knowledge diffusion and U.S. government technology policy: Issues and opportunities for sci/tech librarians

Federal involvement in stimulating economic growth through the development and application of technology policy is currently the subject of serious debate. A recession and the recognition that an internationally competitive economy is a prerequisite for the attainment of national goals have fostered a number of technology policy initiatives aimed at improving the economic competitiveness of American industry. This paper suggests that the successful implementation of U.S. technology policy will require the adoption of a knowledge diffusion model, the development of user oriented information products and services, and a more 'activist' approach on the part of sci/tech librarians in the provision of scientific and technical information (STI). These changes will have a dramatic impact on the sci/tech library of the future and the preparation of sci/tech librarians.

Pinelli, Thomas E.↗