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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 937 records · Page 52
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Photoheliograph thermal concepts study. Volume 2: Detailed analysis

The photoheliograph thermal concepts study which was to define and compare the performance of thermal subsystem concepts for each of three photoheliograph designs oriented toward unique solar observation missions is reported. These design and missions are categorized as: (1) A 150-centimeter photoheliograph for large solar observatory (LSO) missions. This design is intended for multiyear orbital operations as a part of a complement of solar telescopes in a free-flying LSO configuration. (2) A 100-centimeter photoheliograph for shuttle sorties. This design is intended for observation periods of up to 2 weeks while mounted in the cargo bay of the shuttle orbiter vehicle. (3) A 100-centimeter photoheliograph for balloon missions. This design is intended to be a design verification unit and precursor to the orbital flight designs. Mission duration is on the order of a single day at an altitude of approximately 24.4 kilometers. For each of these photoheliograph designs, the basic thermal environments, boundary conditions, and applicable thermal control concepts were defined and the interactions between concepts and environments were determined. A baseline thermal control concept was selected for the three classes of photoheliographs described.

Source record↗
NASA NTRS1987

Graph-Plotting Routine

Plotter routine for IBM PC (AKPLOT) designed for engineers and scientists who use graphs as integral parts of their documentation. Allows user to generate graph and edit its appearance on cathode-ray tube. Graph may undergo many interactive alterations before finally dumped from screen to be plotted by printer. Written in BASIC.

Kantak, Anil V.↗
NASA NTRS1988

Theory on the uncertainty in cloud microphysical processes and climate

The interactive role of clouds and precipitation processes in a climate model is investigated. The basic model structure and parameterizations for condensation, evaporation, and precipitation are outlined. Results simulated from the cloud-climate model are discussed. The potential link between microphysical cloud processes and climate is theorized. The need to develop a climatology of the mean particle radius for clouds at the global scale, in order to understand the role of clouds in climate is stressed.

Liou, Kuo-Nan↗
NASA NTRS1992

Formation of auroral arcs via magnetosphere-ionosphere coupling

The aurora results from electrons that first are energized at very high altitudes by the solar wind-earth interactions and then travel down magnetic field lines until they hit the atmosphere. The basic physical processes are described that lead to the energization of these electrons and thus to the aurora.

Lyons, L. R.↗
NASA NTRS1994

A new ejecta shell surrounding a Wolf-Rayet star in the LMC

We have obtained CCD spectra of newly discovered shell-like nebulae around the WN4 star Breysacher 13 and the WN1 star Breysacher 2 in the Large Magellanic Cloud (LMC). The shell around Br 13 shows definite signs of enrichment in both nitrogen and helium, having much stronger (N II) and He I emission lines than are seen in typical LMC H II regions. From the measured electron temperature of about 17,000 K in the shell, we derive He/H and N/O abundance ratios which are factors of 2 and more than 10 higher, respectively, than the average LMC interstellar values. The derived oxygen abundance in the Br 13 shell is down by a factor of 8 compared to the local LMC interstellar medium (ISM); however, the derived electron temperature is affected by the presence of an incomplete shock arising from the interaction of the stellar wind with photoionized material. This uncertainty does not affect the basic conclusion that the Br 13 shell is enriched by processed material from the Wolf-Rayet star. In contrast, the shell around Br 2 shows no clear evidence of enrichment. The nebular spectrum is characterized by extremely strong (O III) and He II emission and very weak (N II). We derive normal He, O, and N abundances from our spectrum. This object therefore appears to be simply a wind-blown structure associated with a relatively dense cloud near the Wolf-Rayet star, although the very high-ionization state of the gas is unusual for a nebula associated with a Wolf-Rayet star.

Garnett, Donald R.↗
NASA NTRS1999

Technology and Advanced Development for a Non-Toxic Orbital Maneuvering System and Reaction Control System for Orbiter Upgrade

NASA intends to pursue technology applications to upgrade the Space Shuttle Orbiter OMS and RCS systems with non-toxic propellants. The primary objectives of an upgraded OMS/RCS are improved safety and reliability, reduced operations and maintenance costs while meeting basic OMS/RCS operational and performance requirements. The OMS/RCS has a high degree of direct interaction with the crew and requires subsystem and components that are compatible with integration into the orbiter vehicle with regard to external mold-line, power and thermal control The non-toxic propulsion technology is also applicable to future Human Exploration and Development of Space (HEDS) missions. The HEDS missions have similar requirements for attitude control and lander descent/ascent propulsion and which will emphasize the use of In-Situ Resource for propellants. When used as a regenerative coolant as in the Shuttle Orbiter OMS combustion chamber, non-toxic fuels such as ethanol are limited in their cooling capacity by the bulk temperature rise permitted to prevent film boiling or possible coking. Typical regeneratively cooled chambers are constructed from highly conductive copper, which maximizes heat transfer, or from low conductivity materials like stainless steel that can also exacerbate cooling problems. For an ethanol cooled application the heat transfer into the fluid must be controlled to reduce the fuel coolant bulk temperature rise. An approach to provide this control is the subject of this report. This report is being issued to document work done by Aerojet on NASA contract NAS 8-98042. Specifically, this project investigates of the use of ethanol, a designated non-toxic fuel, as a coolant for the Space Shuttle Orbital Maneuvering System Engine combustion chamber. The project also addresses a cost reducing fabrication technique for construction of such a combustion chamber. The study contained three major sub-tasks: an analytical investigation and trade study which included layout of a flight type chamber concept, the fabrication and evaluation of formed platelet liner panels and the preparation and testing of mechanical properties specimens representative of a novel hot gas wall concept.

Hayes, W. A.↗
NASA NTRS2000

Mercury, Skylab, Spacehab, International Space Station: A Continuum

We have conducted real research in space. Virtually all that we conducted in the first decade and a half of the space age was government funded and basic research like the carrier vehicles we call satellites and Sputniki, but direction human interaction began with Project Mercury. When the Apollo program ended with success, we got back to research again. Skylab was using Apollo hardware, using Apollo systems in a manner that offered spacious accomodations for researchers. Education began to move into space. This document describes Skylab's role in spaceborne experiments.

Walker, Charles↗
NASA NTRS2001

AVIRIS Reflectance Retrievals: UCSB Users Manual

The following write-up is designed to help students and researchers take Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) radiance data and retrieve surface reflectance. In the event that the software is not available, but a user has access to a reflectance product, this document is designed to provide a better understanding of how AVIRIS reflectance was retrieved. This guide assumes that the reader has both a basic understanding of the UNIX computing environment, and that of spectroscopy. Knowledge of the Interactive Data Language (IDL) and the Environment for Visualizing Images (ENVI) is helpful. This is a working document, and many of the fine details described in the following pages have been previously undocumented. After having read this document the reader should be able to process AVIRIS to reflectance, provided access to all of the code is possible. The AVIRIS radiance data itself is pre-processed at the Jet Propulsion Laboratory (JPL) in Pasadena, California. The first section of this paper describes how to read data from tape and byte-swap the data. Section 2 describes the procedure in preparing support files before running the 'h2o' suite of programs. Section 3 describes the four programs used in the process, h2olut9.f, h2ospl9.f, vlsfit9.f and rfl9.f.

Roberts, Dar A.↗
NASA NTRS2003

Thermo-Mechanical Processing in Friction Stir Welds

Friction stir welding is a solid-phase joining, or welding process that was invented in 1991 at The Welding Institute (TWI). The process is potentially capable of joining a wide variety of aluminum alloys that are traditionally difficult to fusion weld. The friction stir welding (FSW) process produces welds by moving a non-consumable rotating pin tool along a seam between work pieces that are firmly clamped to an anvil. At the start of the process, the rotating pin is plunged into the material to a pre-determined load. The required heat is produced by a combination of frictional and deformation heating. The shape of the tool shoulder and supporting anvil promotes a high hydrostatic pressure along the joint line as the tool shears and literally stirs the metal together. To produce a defect free weld, process variables (RPM, transverse speed, and downward force) and tool pin design must be chosen carefully. An accurate model of the material flow during the process is necessary to guide process variable selection. At MSFC a plastic slip line model of the process has been synthesized based on macroscopic images of the resulting weld material. Although this model appears to have captured the main features of the process, material specific interactions are not understood. The objective of the present research was to develop a basic understanding of the evolution of the microstructure to be able to relate it to the deformation process variables of strain, strain rate, and temperature.

Schneider, Judy↗
NASA NTRS2002

Regional Climate Simulation and Data Assimilation with Variable-Resolution GCMs

Variable resolution GCMs using a global stretched grid (SG) with enhanced regional resolution over one or multiple areas of interest represents a viable new approach to regional climateklimate change and data assimilation studies and applications. The multiple areas of interest, at least one within each global quadrant, include the major global mountains and major global monsoonal circulations over North America, South America, India-China, and Australia. They also can include the polar domains, and the European and African regions. The SG-approach provides an efficient regional downscaling to mesoscales, and it is an ideal tool for representing consistent interactions of globaYlarge- and regionallmeso- scales while preserving the high quality of global circulation. Basically, the SG-GCM simulations are no different from those of the traditional uniform-grid GCM simulations besides using a variable-resolution grid. Several existing SG-GCMs developed by major centers and groups are briefly described. The major discussion is based on the GEOS (Goddard Earth Observing System) SG-GCM regional climate simulations.

Fox-Rabinovitz, Michael S.↗
NASA NTRS2008

NASA and Superalloys: A Customer, a Participant, and a Referee

NASA has had a long history of research and development in the field of superalloys. These efforts have continued today, where the latest advancements in turbine disk and blade technologies are being developed Although NASA does support military flight systems, it s predominant role is in supporting civilian air transportation systems, and thus has goals for improving fuel efficiency, emissions, noise, and safety of today s aircraft. NASA has traditionally served several distinct but complimentary roles as participants in multi-disciplinary research teams, as customers who fund research and development efforts at industry and universities, and as referees who can address broad issues that affect the entire aeronautics community. Because of our longer range viewpoint, we can take on higher risk, higher reward research topics. NASA can also serve as an intermediary between the basic research performed primarily at universities and the development efforts emphasized by industry. By interacting with individual companies, NASA can identify areas of general interest and problems common to a large portion of the aeronautics community, and devise programs aimed at solving these problems. In space missions, NASA is a direct customer responsible for developing vehicles. In the case of the Space Shuttle, NASA has worked with various contractors to design and build numerous components out of superalloys. Another fascinating area for the use of superalloys is in power systems for long life applications in space. Potential missions include providing electric power for deep space missions, surface rovers, including lunar and Mars, and stationary power generators on the lunar surface.

Nathal, Michael V.↗
NASA NTRS2008

NASA and Superalloys: A Customer, a Participant, and a Referee

NASA has had a long history of research and development in the field of superalloys. These efforts have continued today, where the latest advancements in turbine disk and blade technologies are being developed. Although NASA does support military flight systems, its predominant role is in supporting civilian air transportation systems, and thus has goals for improving fuel efficiency, emissions, noise, and safety of today s aircraft. NASA has traditionally served several distinct but complimentary roles as participants in multi-disciplinary research teams, as customers who fund research and development efforts at industry and universities, and as referees who can address broad issues that affect the entire aeronautics community. Because of our longer range viewpoint, we can take on higher risk, higher reward research topics. NASA can also serve as an intermediary between the basic research performed primarily at universities and the development efforts emphasized by industry. By interacting with individual companies, NASA can identify areas of general interest and problems common to a large portion of the aeronautics community, and devise programs aimed at solving these problems. In space missions, NASA is a direct customer responsible for developing vehicles. In the case of the Space Shuttle, NASA has worked with various contractors to design and build numerous components out of superalloys. Another fascinating area for the use of superalloys is in power systems for long life applications in space. Potential missions include providing electric power for deep space missions, surface rovers, including lunar and Mars, and stationary power generators on the lunar surface.

Nathal, Michael V.↗
NASA NTRS2007

Using Satellites to Understand Climate and Climate Change

This viewgraph presentation reviews the measurement of climate with the use of satellites. The basic greenhouse effect, Ice-albedo feedback, climate models and observations, aerosol-cloud interactions, and the Antarctic are discussed, along with the human effect on climate change.

remote sensing↗
NASA NTRS2010

Development and Demonstration of a Computational Tool for the Analysis of Particle Vitiation Effects in Hypersonic Propulsion Test Facilities

In order to improve the understanding of particle vitiation effects in hypersonic propulsion test facilities, a quasi-one dimensional numerical tool was developed to efficiently model reacting particle-gas flows over a wide range of conditions. Features of this code include gas-phase finite-rate kinetics, a global porous-particle combustion model, mass, momentum and energy interactions between phases, and subsonic and supersonic particle drag and heat transfer models. The basic capabilities of this tool were validated against available data or other validated codes. To demonstrate the capabilities of the code a series of computations were performed for a model hypersonic propulsion test facility and scramjet. Parameters studied were simulated flight Mach number, particle size, particle mass fraction and particle material.

Perkins, Hugh Douglas↗
NASA NTRS2005

Displacing Unpredictable Nulls in Antenna Radiation Patterns

A method of maintaining radio communication despite the emergence of unpredictable fades and nulls in the radiation pattern of an antenna has been proposed. The method was originally intended to be applied in the design and operation of a radio antenna aboard a robotic exploratory vehicle on a remote planet during communication with a spacecraft in orbit around the planet. The method could also be applied in similar terrestrial situations for example, radio communication between two ground vehicles or between a ground vehicle and an aircraft or spacecraft. The method is conceptually simple, is readily adaptable to diverse situations, and can be implemented without adding greatly to the weight, cost, power demand, or complexity of a system to which it may be applied. The unpredictable fades and nulls in an antenna radiation pattern arise because of electromagnetic interactions between the antenna and other objects within the near field of the antenna (basically, objects within a distance of a few wavelengths). These objects can include general vehicle components, masts, robotic arms, other antennas, the ground, and nearby terrain features. Figure 1 presents representative plots of signal strength versus time during a typical pass of a spacecraft or aircraft through the far field of such an antenna, showing typical nulls and fades caused by nearby objects. The traditional approach to ensuring reliability of communication in the presence of deep fades calls for increasing the effective transmitter power and/or reducing the receiver noise figure at the affected ground vehicle, possibly in combination with appropriate redesign of the equipment at the spacecraft or aircraft end of the communication link. These solutions can be expensive and/or risky and, depending on the application, can add significantly to weight, cost, and power demand. The proposed method entails none of these disadvantages.

Lux, James↗
DOE OSTI2012

PITCH-ANGLE SCATTERING: RESONANCE VERSUS NONRESONANCE, A BASIC TEST OF THE QUASILINEAR DIFFUSIVE RESULT

Due to the very broad range of the scales available for the development of turbulence in space and astrophysical plasmas, the energy at the resonant scales of wave-particle interaction often constitutes only a tiny fraction of the total magnetic turbulent energy. Despite the high efficiency of resonant wave-particle interaction, one may therefore question whether resonant interaction really is the determining interaction process between particles and turbulent fields. By evaluating and comparing resonant and nonresonant effects in the frame of a quasilinear calculation, the dominance of resonance is here put to the test. By doing so, a basic test of the classical resonant quasilinear diffusive result for the pitch-angle scattering of charged energetic particles is also performed.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2023

Construction and Modeling of a Coculture Microplate for Real-Time Measurement of Microbial Interactions

The dynamic structures of microbial communities emerge from the complex network of interactions between their constituent microorganisms. Quantitative measurements of these interactions are important for understanding and engineering ecosystem structure. Here, we present the development and application of the BioMe plate, a redesigned microplate device in which pairs of wells are separated by porous membranes. BioMe facilitates the measurement of dynamic microbial interactions and integrates easily with standard laboratory equipment. We first applied BioMe to recapitulate recently characterized, natural symbiotic interactions between bacteria isolated from the Drosophila melanogaster gut microbiome. Specifically, the BioMe plate allowed us to observe the benefit provided by two Lactobacillus strains to an Acetobacter strain. We next explored the use of BioMe to gain quantitative insight into the engineered obligate syntrophic interaction between a pair of Escherichia coli amino acid auxotrophs. We integrated experimental observations with a mechanistic computational model to quantify key parameters associated with this syntrophic interaction, including metabolite secretion and diffusion rates. This model also allowed us to explain the slow growth observed for auxotrophs growing in adjacent wells by demonstrating that, under the relevant range of parameters, local exchange between auxotrophs is essential for efficient growth. The BioMe plate provides a scalable and flexible approach for the study of dynamic microbial interactions.

3D printed device↗