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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 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
NASA NTRS1988

On the theory of the conversion of metallic mixed phases. 5: Fluctuations and nucleation in sub-cooled phases

A comparison is made between fluctuation-theoretical calculations and empirical results. Concentration fluctuations and the resulting separation, and the distribution function of the reversible fluctuations are approximately calculated. The relation of this distribution to the concentration-dependence of the free energy is discussed. Possible effects of fluctuations are discussed, and other attempts to explain the sub-cooling are described.

Borelius, G.↗
NASA NTRS1991

The TurboLAN project. Phase 1: Protocol choices for high speed local area networks. Phase 2: TurboLAN Intelligent Network Adapter Card, (TINAC) architecture

The hardware and the software architecture of the TurboLAN Intelligent Network Adapter Card (TINAC) are described. A high level as well as detailed treatment of the workings of various components of the TINAC are presented. The TINAC is divided into the following four major functional units: (1) the network access unit (NAU); (2) the buffer management unit; (3) the host interface unit; and (4) the node processor unit.

Alkhatib, Hasan S.↗
NASA NTRS1990

Two-dimensional simulation of a two-phase, regenerative pumped radiator loop utilizing direct contact heat transfer with phase change

An innovative pumped loop concept for 600 K space power system radiators utilizing direct contact heat transfer, which facilitates repeated startup/shutdown of the power system without complex and time-consuming coolant thawing during power startup, is under development. The heat transfer process with melting/freezing of Li in an NaK flow was studied through two-dimensional time-dependent numerical simulations to characterize and predict the Li/NaK radiator performance during startup (thawing) and shutdown (cold-trapping). Effects of system parameters and the criteria for the plugging domain are presented together with temperature distribution patterns in solid Li and subsequent melting surface profile variations in time.

Rhee, Hyop S.↗
NASA NTRS1997

Results From Phase-1 and Phase-2 GOLD Experiments

The Ground/Orbiter Lasercomm Demonstration conducted between the Japanese Engineering Test Satellite (ETS-VI) and the ground station at JPL's Table Mountain Facility, Wrightwood, California, was the rst ground-to-space two-way optical communications experiment. Experiment objectives included validating the performance predictions of the optical link. Atmospheric attenuation and seeing measurements were made during the experiment, and data were analyzed. Downlink telemetry data recovered over the course of the experiment provided information on in-orbit performance of the ETS-VI's laser communications equipment. Biterror rates as low as 10 4 were measured on the uplink and 10 5 on the downlink. Measured signal powers agreed well with theoretical predictions.

Wilson, K.↗
NASA NTRS2005

Liquid-Phase Deposition of Single-Phase Alpha-Copper-Indium-Diselenide

The success of exploratory missions in outer space often depends on a highly efficient renewable energy supply, as provided by solar cells. Figure 1 shows a well-known example: The robotic vehicle "Rover," constructed for NASA s "Mars Pathfinder" mission. The solar cells for such applications not only need to have high conversion efficiency, but must possess a high specific power, thus a high power output per unit mass. Since future missions will demand for large aggregates of solar cells and space flights are expensive, the solar cells must furthermore be available at low costs (per unit power output) and - very important in outer space - have a long lifetime and a high resistance against structural damage introduced by irradiation with high-energy electrons and protons.

Cowen, J.↗
NASA NTRS2010

Microbiological Tests Performed During the Design of the International Space Station Environmental Control and Life Support Systems. Part 1, Bulk Phase: Bulk Phase - Part 1

The design and manufacturing of the main Environmental Control and Life Support Systems (ECLSS) for the United States segments of the International Space Station (ISS) was an involved process that started in the mid 1980s, with the assessment and testing of competing technologies that could be used to clean the air and recycle water. It culminated in 2009 with the delivery and successful activation of the Water Recovery System (WRS) water processor (WP). The ECLSS required the work of a team of engineers and scientist working together to develop systems that could clean and/or recycle human metabolic loads to maintain a clean atmosphere and provide the crew clean water. One of the main goals of the ECLSS is to minimize the time spent by the crew worrying about vital resources not available in the vacuum of space, which allows them to spend most of their time learning to live in a microgravity environment many miles from the comforts of Earth and working on science experiments. Microorganisms are a significant part of the human body as well as part of the environment that we live in. Therefore, the ISS ECLSS design had to take into account the effect microorganisms have on the quality of stored water and wastewater, as well as that of the air systems. Hardware performance issues impacted by the accumulation of biofilm and/or microbiologically influenced corrosion were also studied during the ECLSS development stages. Many of the tests that were performed had to take into account the unique aspects of a microgravity environment as well as the challenge of understanding how to design systems that could not be sterilized or maintained in a sterile state. This paper will summarize the work of several studies that were performed to assess the impacts and/or to minimize the effects of microorganisms in open, semi-closed and closed loop life support system. The biofilm and biodeterioration studies that were performed during the design and test periods will be presented in a future publication.

Roman, Monsi C.↗
NASA NTRS2000

Nutritional Status Assessment During the Phase IIA and Phase III Lunar/Mars Life Support Test Project

Nutrition is a critical concern for extended-duration space missions (Smith and Lane, 1999). Loss of body weight is a primary consequence of altered nutrition, and is frequently observed during space flight (Smith and Lane; 1999). Other existing dietary concerns for space flight include excessive intakes of sodium and iron, and insufficient intakes of water and vitamin D (Smith and Lane, 1999). Furthermore, dependence on closed or semi-closed food systems increases the likelihood of inadequate intakes of key nutrients. This is a significant concern for extended-duration space missions. Space nutrition research often necessitates detailed recording of all food consumption. While this yields extremely accurate data, it requires considerable time and effort, and thus is not suitable for routine medical monitoring during space flight. To alleviate this problem, a food frequency questionnaire (FFQ) was designed to provide a quick and easy, yet reasonably accurate, method for crewmembers to provide dietary intake information to the ground. We report here a study which was designed to assess nutritional status before, during, and after the 60-d and 91-d chamber stays. An additional goal of the study was to validate a food frequency questionnaire designed specifically for use with space flight food systems.

Smith, Scott M.↗
NASA NTRS2013

The North American Multi-Model Ensemble (NMME): Phase-1 Seasonal to Interannual Prediction, Phase-2 Toward Developing Intra-Seasonal Prediction

The recent US National Academies report "Assessment of Intraseasonal to Interannual Climate Prediction and Predictability" was unequivocal in recommending the need for the development of a North American Multi-Model Ensemble (NMME) operational predictive capability. Indeed, this effort is required to meet the specific tailored regional prediction and decision support needs of a large community of climate information users. The multi-model ensemble approach has proven extremely effective at quantifying prediction uncertainty due to uncertainty in model formulation, and has proven to produce better prediction quality (on average) then any single model ensemble. This multi-model approach is the basis for several international collaborative prediction research efforts, an operational European system and there are numerous examples of how this multi-model ensemble approach yields superior forecasts compared to any single model. Based on two NOAA Climate Test Bed (CTB) NMME workshops (February 18, and April 8, 2011) a collaborative and coordinated implementation strategy for a NMME prediction system has been developed and is currently delivering real-time seasonal-to-interannual predictions on the NOAA Climate Prediction Center (CPC) operational schedule. The hindcast and real-time prediction data is readily available (e.g., http://iridl.ldeo.columbia.edu/SOURCES/.Models/.NMME/) and in graphical format from CPC (http://origin.cpc.ncep.noaa.gov/products/people/wd51yf/NMME/index.html). Moreover, the NMME forecast are already currently being used as guidance for operational forecasters. This paper describes the new NMME effort, presents an overview of the multi-model forecast quality, and the complementary skill associated with individual models.

NOAA CPC↗
NASA NTRSDate not supplied

Data and Reasoning Fabric (DRF) Phase I & Phase II Report

A Data & Reasoning Fabric (DRF) is envisioned to enable the full potential of advanced air mobility by providing all data and reasoning where they are needed. The DRF marketplace is based on an open foundational ecosystem of data and reasoning exchange between the many systems that must seamlessly interplay to manage the envisioned highly complex and dense airspace operations. DRF activities will identify, test and - as needed - research and develop critical core technologies, and collaboratively test these technologies, open standards and architectures, and the integrated framework with end-users so as to deliver reference designs and development environments that catalyze broad private and public sector buy-in and self-sustaining development of it and associated standards.

UAM↗