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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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Exciton and charge transfer processes within singlet fission micelles
Multiexciton (ME) mechanisms hold great promise for enhancing energy conversion efficiency in optoelectronic and photochemical systems.
A study of inert-gas welding process transferability of set-up parameters
Feasibility of transferring TIG weld settings and obtaining similar weld characteristics
A study of inert-gas welding process transferability of set-up parameters Final report
Test program and statistical analysis of setup parameter transferability for inert gas welding
Study of a contractors capabilities center and the technology transfer process Final report, 15 Mar. 1966 - 30 Jun. 1968
Feasibility of NASA Contractors Capabilities Center, and approaches to technology utilization
Stabilization of n-type semiconductors to photoanodic dissolution by competitive electron transfer processes
The behavior of n-type CdX (X = S, Se, Te) and GaP, GaAs, and InP in alkaline electrolytes containing X(--) and X sub n(--) ions is reviewed. Of the 18 combinations of electrode and electrolyte, 12 alliances are completely stable to photoanodic dissolution of the n-type photoanode. In each case the oxidation of the chalcogenide species at the photoanode is reversed at the cathode to complete an electrochemical cycle involving no net chemical change. The best system in terms of light-to-electric energy conversion seems to be the CdTe-based cell employing the Te(--)/Te2(--) electrolyte, with roughly 10% efficiency at an output voltage of 0.35 V for monochromatic 633 nm input optical energy at about 25 mW/sq cm.
Substorms and magnetospheric energy transfer processes
Evidence is presented which suggests a direct process for the conversion of solar wind energy into the various manifestations of the auroral substorm. This is in contrast to the widely accepted premise that solar wind energy is accumulated in the magnetosphere and then released by an instability process occurring in the magnetotail. It is shown that much of the plasma sheet behavior associated with auroral substorms can be interpreted in terms of single-particle models and simple variations of the cross-tail electric field intensity which does not invoke release of stored magnetic energy. It is also pointed out that the major entry of substorm energy into the magnetosphere occurs through the boundaries of the lobes of the magnetotail. This paper is not intended to be a complete theory of the magnetospheric substorm - rather the intention of this paper is to point out directions of research deserving of more attention.
The magnetotail boundary and energy transfer processes
A particle code is used to simulate the magnetopause region in the high latitude geomagnetic tail in which the magnetic field undergoes a significant increase in going from the magnetosheath to the magnetotail lobe. The simulation indicates that plasma can flow from the magnetosheath to the lobe, which is accompanied by a drop in pressure and density. In the earth's inertial frame, the particles do work against the convection electric field. Hence the magnetopause region serves as a dynamo. The simulation also shows that the width of the transition region increases with time. In the earth's inertial frame this is seen as an expansion of the magnetopause thickness in the antisunward direction.
Monitoring sediment transfer processes on the desert margin
LANDSAT Thematic Mapper and Multispectral Scanner data have been used to construct change detection images for three playas in south-central Tunisia. Change detection images have been used to analyze changes in surface reflectance and absorption between wet and dry season (intra-annual change) and between different years (inter-annual change). Change detection imagery has been used to examine geomorphological changes on the playas. Changes in geomorphological phenomena are interpreted from changes in soil and foliar moisture levels, differences in reflectances between different salt and sediments and the spatial expression of geomorphological features. Intra-annual change phenomena that can be detected from multidate imagery are changes in surface moisture, texture and chemical composition, vegetation cover and the extent of aeolian activity. Inter-annual change phenomena are divisible into those restricted to marginal playa facies (sedimentation from sheetwash and alluvial fans, erosion from surface runoff and cliff retreat) and these are found in central playa facies which are related to the internal redistribution of water, salt and sediment.
Heat-transfer processes in liquid-cooled engine cylinders I : correlation of single-cylinder engine temperatures under forced-convection cooling conditions
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Joint sessions on modeling of boundary layer and radiative transfer processes
During the session on modeling of the planetary boundary layer (PBL) processes the following topics were addressed: current PBL parameterizations used in mesoscale models; critical issues in improving PBL parameterizations for mesoscale models; suggestions for future modeling efforts; and suggestions for observing system strategies.
On-line in-situ control of the resin transfer molding process
Resin transfer molding of three-dimensionally stitched fabrics promises to be a cost effective process for obtaining composite parts of exceptional strength. The technique eliminates many problems involving prepreg preparation, storage and layup. It replaces, on the other hand, the single step cure process with a two-stage impregnation and cure process. Of particular importance therefore is selecting and controlling the viscosity during impregnation and cure. The use of in-situ frequency-dependent electromagnetic sensors and the Loos-Springer model for selecting and controllng the processing properties of the resin transfer molding resin during impregnation and cure are discussed.
NASA Office of Aeronautics and Space Technology Summer Workshop. Volume 1: Data processing and transfer panel
The data processing and transfer technology areas that need to be developed and that could benefit from space flight experiments are identified. Factors considered include: user requirements, concepts in 'Outlook for Space', and cost reduction. Major program thrusts formulated are an increase in end-to-end information handling and a reduction in life cycle costs.
Composition of and Method for Making High Performance Resins for Infusion and Transfer Molding Processes
A composition of and method for making high performance imide resins that are processable by resin transfer molding (RTM) and resin infusion (RI) techniques were developed. Materials with a combination of properties, making them particularly useful for the fabrication of composite parts via RTM and/or RI processes, were prepared, characterized and fabricated into moldings and carbon fiber reinforced composites and their mechanical properties were determined. These materials are particularly useful for the fabrication of structural composite components for aerospace applications. The method for making high performance resins for RTM and RI processes is a multi-faceted approach. It involves the preparation of a mixture of products from a combination of aromatic diamines and aromatic dianhydrides at relatively low calculated molecular weights (i.e. high stoichiometric offsets) and endcapping with latent reactive groups. The combination of these monomers results in a mixture of products, in the imide form, that exhibits a stable melt viscosity of less than approximately 60 poise below approximately 300 C.
Capturing Coupled Structural and Electronic Motions During Excited-State Intramolecular Proton Transfer via Computational Multiedge Resonant Inelastic X-ray Scattering
Proton-transfer processes build the foundation of many chemical processes. In Excited State Intramolecular Proton Transfer (ESIPT) processes the proton transfer process is impulsively started through light. Here, in this study, we explore the changes in coupled atomic and electronic motions during and following ESIPT through computational time-resolved Resonant Inelastic X-ray Scattering (trRIXS). Excited-state Ab Initio Molecular Dynamics (AIMD) simulations combined with Time-Dependent Density Functional Theory (TDDFT) calculations were performed for 10-hydroxybenzo[h]quinoline to obtain trRIXS signatures. RIXS at both the nitrogen and oxygen K-edges were computed to resolve the dynamics electronic structure from both the proton donor and acceptor perspective. The results show how RIXS can reveal the local electronic structure, the coupling between different electronic states and how electronic structure and coupling change during the proton transfer process. Additionally, we observe a strong correlation between spectral changes and structural changes during ESIPT.
Software engineering technology transfer: Understanding the process
Technology transfer is of crucial concern to both government and industry today. In this report, the mechanisms developed by NASA to transfer technology are explored and the actual mechanisms used to transfer software development technologies are investigated. Time, cost, and effectiveness of software engineering technology transfer is reported.
Rocket engine thrust chamber wall temperature distribution calculation and analysis
An analytical computational concept is presented which predicts the temperature profiles along a regeneratively cooled thrust chamber wall on the hot gas side and on the coolant side, and also the coolant bulk temperature profile. The computational model is based upon a coupling of the boundary layer heat transfer process with the heat transfer process through the chamber wall and the coolant flow heat absorption. The calculation is started with approximate temperature distributions for the hot gas side wall and the coolant flow. The iteration process of the computer program is terminated when the total heat transfer rates from the hot gas boundary layer to the wall and from the wall to the coolant are equal. The computer program for the integration of regenerative cooling process to a thrust chamber is kept general such that this program can be used with any boundary layer analysis computer program for temperature profile and heat transfer studies. A sample application of this concept is shown by using a boundary layer analysis program for the RL10 rocket engine thrust chamber.
All-atmospheric fabrication of Ag–Cu core–shell nanowire transparent electrodes with Haacke figure of merit >600 × 10–3 Ω−1
Abstract Transparent conducting electrodes (TCEs) are essential components in devices such as touch screens, smart windows, and photovoltaics. Metal nanowire networks are promising next-generation TCEs, but best-performing examples rely on expensive metal catalysts (palladium or platinum), vacuum processing, or transfer processes that cannot be scaled. This work demonstrates a metal nanowire TCE fabrication process that focuses on high performance and simple fabrication. Here we combined direct and plating metallization processes on electrospun nanowires. We first directly metallize silver nanowires using reactive silver ink. The silver catalyzes subsequent copper plating to produce Ag–Cu core–shell nanowires and eliminates nanowire junction resistances. The process allows for tunable transmission and sheet resistance properties by adjusting electrospinning and plating time. We demonstrate state-of-the-art, low-haze TCEs using an all-atmospheric process with sheet resistances of 0.33 Ω sq −1 and visible light transmittances of 86% (including the substrate), leading to a Haacke figure of merit of 652 × 10 –3 Ω −1 . The core–shell nanowire electrode also demonstrates high chemical and bending durability.