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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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS2019

NASA Disasters Program: A Partner for Coastal Disaster Response, Resiliency, and Risk Reduction

Summary: The NASA Applied Sciences: Disasters Program has kicked off a pilot project as “Mid-Atlantic Resiliency Demonstration Study, Communities at Intensive Risk” in FY17 and FY18; Efforts focus on a holistic, interdisciplinary approach to integrate a full suite of capabilities from numerical weather prediction, tide and surge modeling at high spatial resolution and urban/neighborhood scales, and remote sensing capabilities for water detection and depth estimation; Future efforts - Partner with Federal Agencies, academia professional societies to complement and augment ongoing work using Earth observations unique to NASA - Translate hazards to risk in order to understand local and regional impacts and minimize vulnerability.

Bell, Jordan↗
NASA NTRS2019

Estimated Refractive Indices of Calcite, Dolomite, and Magnesite: ~0.3-500 M.

Carbonate minerals are germane to questions involving volatile and climate history on Mars [e.g., 1-2]. In particular, the abundance of carbonate-bearing minerals can provide broad useful bounds on the amount of CO2 out-gassed into the atmosphere over its history and their spatial distribution and mineralogy can yield constraints on the environments in which they were produced. Earth-based, orbital, and landed spectral observations provide evidence for the presence of carbonates in the Martian environment [3-6]. Infrared observations made from spacecraft near Mars were interpreted to indicate the presence of carbonates. [6] associated the carbonates with the surface dust and interpreted the mineralogy as being consistent with magnesite (MgCO3). Near- infrared observations from Mars orbit have been interpreted to suggest magnesite outcrops in restricted locations [7-9]. Quantitative estimates of the abundance of carbonates on Mars range from 0-3% [3], 2-5% [6], less than a few percent [10], and <10% [8]. With the growing evidence for magnesite on Mars additional quantitative estimates can be provided via theoretical modeling of the reflectance from the Martian surface. Calcite (CaCO3) and dolomite ((Ca,Mg)CO3) are identified in Asian dust [2-17%], [10] and calcite in Saharan dust [~8-10% [12-15]. The importance of op- tical constants at visible and near-infrared wavelengths as proxies for estimating the effects at infrared wave- lengths, has been investigated [15]. The growing evidence for Mg-carbonates on Mars, the presence of calcite and dolomite in terrestrial aero- sols, and general lack of optical constants for these materials in the visible- to mid-infrared (VMIR, ~0.3-6 ❍m) has motivated the current effort to estimate the optical constants of calcite, dolomite, and magnesite in the VMIR.

Roush, T. L.↗
NASA NTRS2017

Assessment of Urban Aerial Taxi with Cryogenic Components under Design Environment for Novel Vertical Lift Vehicles (DELIVER)

Assessing the potential to bring 100 years of aeronautics knowledge to the entrepreneurs desktop to enable a design environment for emerging vertical lift vehicles is one goal for the NASAs Design Environment for Novel Vertical Lift Vehicles (DELIVER). As part of this effort, a system study was performed using a notional, urban aerial taxi system to better understand vehicle requirements along with the tools and methods capability to assess these vehicles and their subsystems using cryogenic cooled components. The baseline was a vertical take-off and landing (VTOL) aircraft, with all-electric propulsion system assuming 15 year technology performance levels and its capability limited to a pilot with one or two people and cargo. Hydrocarbon-fueled hybrid concepts were developed to improve mission capabilities. The hybrid systems resulted in significant improvements in maximum range and number of on demand mobility (ODM) missions that could be completed before refuel or recharge. An important consideration was thermal management, including the choice for air-cooled or cryogenic cooling using liquid natural gas (LNG) fuel. Cryogenic cooling for critical components can have important implications on component performance and size. Thermal loads were also estimated, subsequent effort will be required to verify feasibility for cooling airflow and packaging. LNG cryogenic cooling of selected components further improved vehicle range and reduced thermal loads, but the same concerns for airflow and packaging still need to be addressed. The use of the NASA Design and Analysis of Rotorcraft (NDARC) tool for vehicle sizing and mission analysis appears to be capable of supporting analyses for present and future types of vehicles, missions, propulsion, and energy sources. Further efforts are required to develop verified models for these new types of propulsion and energy sources in the size and use envisioned for these emerging vehicle and mission classes.

systems analysis↗
NASA NTRS2017

Assessment of Urban Aerial Taxi with Cryogenic Components Under Design Environment for Novel Vertical Lift Vehicles (DELIVER)

Assessing the potential to bring 100 years of aeronautics knowledge to the entrepreneurs desktop to enable a design environment for emerging vertical lift vehicles is one goal for the NASA's Design Environment for Novel Vertical Lift Vehicles (DELIVER). As part of this effort, a system study was performed using a notional, urban aerial taxi system to better understand vehicle requirements along with the tools and methods capability to assess these vehicles and their subsystems using cryogenic cooled components. The baseline was a vertical take-off and landing (VTOL) aircraft, with all-electric propulsion system assuming 15 year technology performance levels and its capability limited to a pilot with one or two people and cargo. Hydrocarbon-fueled hybrid concepts were developed to improve mission capabilities. The hybrid systems resulted in significant improvements in maximum range and number of on demand mobility (ODM) missions that could be completed before refuel or recharge. An important consideration was thermal management, including the choice for air-cooled or cryogenic cooling using liquid natural gas (LNG) fuel. Cryogenic cooling for critical components can have important implications on component performance and size. Thermal loads were also estimated, subsequent effort will be required to verify feasibility for cooling airflow and packaging. LNG cryogenic cooling of selected components further improved vehicle range and reduced thermal loads, but the same concerns for airflow and packaging still need to be addressed. The use of the NASA Design and Analysis of Rotorcraft (NDARC) tool for vehicle sizing and mission analysis appears to be capable of supporting analyses for present and future types of vehicles, missions, propulsion, and energy sources. Further efforts are required to develop verified models for these new types of propulsion and energy sources in the size and use envisioned for these emerging vehicle and mission classes.

thermal analysis↗
DOE OSTI2021

Comparing deuterium excess to large-scale precipitation recycling models in the tropics

Precipitation recycling is essential to sustaining regional ecosystems and water supplies, and it is impacted by land development and climate change. This is especially true in the tropics, where dense vegetation greatly influences recycling. Unfortunately, large-scale models of recycling often exhibit high uncertainty, complicating efforts to estimate recycling. Here, we examine how deuterium excess (d-excess), a stable-isotope quantity sensitive to recycling effects, acts as an observational proxy for recycling. While past studies have connected variability in d-excess to precipitation origins at local or regional scales, our study leverages >3000 precipitation isotope samples to quantitatively compare d-excess against three contemporary recycling models across the global tropics. Using rank-correlation, we find statistically significant agreement ( $\bar \tau = 0.52$ τ ¯ = 0.52 to $0.70$ 0.70 ) between tropical d-excess and recycling that is strongly mediated by seasonal precipitation, vegetation density, and scale mismatch. Our results detail the complex relationship between d-excess and precipitation recycling, suggesting avenues for further investigation.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

Cost & Performance Requirements for Flexible Advanced Nuclear Plants in Future U.S. Power Markets

This report summarizes a modeling effort to estimate the highest allowable CapEx for advanced nuclear plants in future power market environments to still achieve a market rate of return for their owners. This is not a policy report making recommendations to policymakers about how to regulate power markets. Rather, the study’s assumptions and scenarios reflect likely market conditions across a large percentage of US electricity markets. Its goal is to define target cost and performance parameters determined by future market conditions in order to guide design choices and tradeoffs in the early stage of the reactor and power plant development process. Although this was not a deployment modeling exercise to determine the market size for a given technology at selected price points, it does suggest that advanced reactors delivered under the allowable CapEx thresholds identified in this report could cost competitively serve a significant fraction of load in the modeled power markets.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2021

Rare Event Sampling Improves Mercury Instability Statistics

Due to the chaotic nature of planetary dynamics, there is a non-zero probability that Mercury's orbit will become unstable in the future. Previous efforts have estimated the probability of this happening between 3 and 5 billion years in the future using a large number of direct numerical simulations with an N-body code, but were not able to obtain accurate estimates before 3 billion years in the future because Mercury instability events are too rare. In this paper we use a new rare-event sampling technique, Quantile Diffusion Monte Carlo (QDMC), to estimate that the probability of a Mercury instability event in the next 2 billion years is approximately 10 –4 in the REBOUND N-body code. We show that QDMC provides unbiased probability estimates at a computational cost of up to 100 times less than direct numerical simulation. QDMC is easy to implement and could be applied to many problems in planetary dynamics in which it is necessary to estimate the probability of a rare event.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1980

ERBE - Assessment of measurement accuracy

The Earth Radiation Budget Experiment (ERBE) represents a continuing effort to estimate the solar incident and earth reflected and emitted radiance from spacecraft measurements. The development of accurate and stable sensors and calibration sources is mandatory but not sufficient to attain and validate required measurement accuracies. It is also necessary to develop and experimentally test computational models of the calibration and measurement processes to account for environmental differences between (static) calibrations and (dynamic) measurements of the earth radiant exitance that varies with wavelength, position, direction, and time.

Spiers, R. B., Jr.↗
NASA NTRS1984

Large Scale Rossby Waves During FGGE

The purpose was to explore the behavior and significance of global-scale rotational normal modes (free Rossby waves) in the atmosphere. Although these modes received a great deal of attention n the past, the lack of accurate global data severely hampered efforts at estimating the amplitudes and time dependence of these waves in the real atmosphere. With the First GARP Global Experiment, the availability of accurate data that is truly global in coverage presents an important opportunity for a better understanding of the role of Rossby waves in the atmosphere. In the results presented, emphasis is placed on the temporal evolution of the amplitude and phase of the Rossby waves, rather than on characteristics of the time spectra of these waves. The first steps of the analysis consisted of projecting the 500 mb height and wind data onto Hough functions for each synoptic time. The seasonal cycle and time mean were removed separately for each season, and all remaining eastward propagating components removed on a seasonal basis; all remaining westward propagating components were retained.

Lindzen, R. S.↗
NASA NTRS1990

Investigation of the reaction kinetics between SiC fibers and selectively alloyed titanium matrix composites and determination of their mechanical properties

During high temperature exposure, an interfacial reaction occurs between SiC fiber reinforcement and titanium matrices which can be detrimental to the mechanical properties of the composite. The reaction kinetics between SCS-6 fibers and Ti-1100 were determined at 800 to 1000 C and found to be slower than those of other currently used titanium alloys (Ti-15-3, Ti-6-4). The experimentally determined reaction kinetics for Ti-1100 were extrapolated to 700 C and found to accurately predict reaction zone size after 1000 hours of exposure. Predictions of the time to consume the surface layer on the SCS-6 and SCS-9 fibers were made in an effort to estimate the time that the fiber will retain its strength in Ti-1100 during isothermal exposure at high temperatures. Using this approach, the strength of an SCS-6 fiber in Ti-1100 should be retained for over 20,000 hours at isothermal exposures less than 800 C. Strength predictions using the rule of mixtures for a unidirectional Ti-1100/SCS-6 composite are presented for short term exposures up to 700 C. Room temperature tests of an as-fabricated 20 volume percent fiber/Ti-1100 composite yielded a UTS of 226 ksi (1490 MPa) which is close to that predicted by the ROM.

Gundel, Douglas B.↗
NASA NTRS1990

Deuterium enrichment in the primitive ices of the protosolar nebula

On the basis of CH3D/CH4-ratio observations in the outer planets, the present effort to estimate the D/H ratio of the protosolar nebula's primitive ices arrives at two simple, yet effectively limiting models which constrain the degree of dilution undergone by deuterated volatiles through mixing with the initial hydrogen envelopes. These volatiles would have been contributed to planetary atmospheres by evaporated primordial ices. Ice D/H ratio model results of 0.0001 to 0.001 are compared with values for other potentially primitive material-containing bodies in the solar system, as well as with D/H ratio values from interstellar polyatomic molecules.

Lutz, Barry L.↗
NASA NTRS1993

Automated Estimation Of Software-Development Costs

COSTMODL is automated software development-estimation tool. Yields significant reduction in risk of cost overruns and failed projects. Accepts description of software product developed and computes estimates of effort required to produce it, calendar schedule required, and distribution of effort and staffing as function of defined set of development life-cycle phases. Written for IBM PC(R)-compatible computers.

Roush, George B.↗
NASA NTRS1993

Fabrication and properties of functionally graded NiAl/Al2O3 composites

A modified sedimentation process was used in the production of a functionally gradient material (FGM), NiAl/Al2O3. A simple finite element model was used to guide our design and fabrication efforts by estimating residual stress states as a function of composite structure. This approach could lead to tailored designs that enhance or avoid specific residual stress states. Thermal cycling tests were factored into the model to predict time dependent or steady-state internal temperature and stress profiles. Four-point bend tests were conducted to establish the mechanical load-displacement behavior of a single interlayer FGM at room temperature, 800 and 1000 K. Room temperature bend strength of the FGM was 3-4 times that of the base NiAl. At elevated temperatures, composite fracture occurred in a gradual, noncatastrophic mode involving NiAl retardation of a succession of cracks originating in the alumina face.

Miller, D. P.↗
NASA NTRS1996

Orbital debris removal using ground-based lasers

Orbiting the Earth are spent rocket stages, non-functioning satellites, hardware from satellite deployment and staging, fragments of exploded spacecraft, and other relics of decades of space exploration: orbital debris. The United States Space Command tracks and maintains a catalog of the largest objects. The catalog contains over 7000 objects. Recent studies have assessed the debris environment in an effort to estimate the number of smaller particles and the probability of a collision causing catastrophic damage to a functioning spacecraft. The results of the studies can be used to show, for example, that the likelihood of a collision of a particle larger than about one centimeter in diameter with the International Space Station during a 10-year period is a few percent, roughly in agreement with earlier estimates for Space Station Freedom. Particles greater than about one centimeter in diameter pose the greatest risk to shielded spacecraft. There are on the order of 105 such particles in low Earth orbit. The United States National Space Policy, begun in 1988, is to minimize debris consistent with mission requirements. Measures such as venting unused fuel to prevent explosions, retaining staging and deployment hardware, and shielding against smaller debris have been taken by the U.S. and other space faring nations. There is at present no program to remove debris from orbit. The natural tendency for upper atmospheric drag to remove objects from low Earth orbit is more than balanced by the increase in the number of debris objects from new launches and fragmentation of existing objects. In this paper I describe a concept under study by the Program Development Laboratory of Marshall Space Flight Center and others to remove debris with a ground-based laser. A longer version of this report, including figures, is available from the author.

Taylor, Charles R.↗
NASA NTRS1996

A Search for Extraterrestrial Amino Acids in Polar Ice: A Progress Report

Fifteen polar ice samples-fourteen from Greenland and one from Antarctica-have been analyzed for the extraterrestrial amino acid alpha-aminoisobutyric acid (AIB) in an effort to estimate the flux of interplanetary organic material to the Earth's surface. Only one sample (Greenland GISP II, 4270-4440 years old) contains detectable amounts of AIB, apparently the signature of a transient delivery event. The maximum oceanic concentration of AIB from such an event would be less than 10(exp-9) M.

Bada, Jeffrey L.↗
NASA NTRS2003

Transient Interfacial Phenomena in Miscible Polymer Systems (TIPMPS)

Almost one hundred years ago Korteweg published a theory of how stresses could be induced in miscible fluids by concentration gradients, causing phenomena that would appear to be the same as with immiscible fluids. Miscible fluids could manifest a transient or effective interfacial tension (EIT). To this day, there has been no definitive experiment to confirm Korteweg's model but numerous fascinating and suggestive experiments have been reported. The goal of TIPMPS is to answer the question: Can concentration and temperature gradients in miscible materials induce stresses that cause convection? Many polymer processes involving miscible monomer and polymer systems could be affected by fluid flow and so this work could help understand miscible polymer processing, not only in microgravity, but also on earth. Demonstrating the existence of this phenomenon in miscible fluids will open up a new area of study for materials science. The science objectives of TIPMPS are: (1) Determine if convection can be induced by variation of the width of a miscible interface; (2) Determine if convection can be induced by variation of temperature along a miscible interface; (3) Determine if convection can be induced by variation of conversion along a miscible interface An interface between two miscible fluids can best be created via a spatially-selective photopolymerization of dodecyl acrylate with a photoinitiator, which allows the creation of precise and accurate concentration gradients between polymer and monomer. Optical techniques will be used to measure the refractive index variation caused by the resultant temperature and concentration fields. The viscosity of the polymer will be measured from the increase in the fluorescence of pyrene. Because the large concentration and temperature gradients cause buoyancy-driven convection that prevents the observation of the predicted flows, the experiment must be done in microgravity. In this report, we will consider our efforts to estimate the square gradient parameter, k, and our use of the estimates in modeling of the planned TIPMPS experiments. We developed a model consisting of the heat and diffusion equations with convective terms and of the Navier-Stokes equations with an additional volume force written in the form of the Korteweg stresses arising from nonlocal interaction in the fluid. The fluid's viscosity dependence on polymer conversion and temperature was taken from measurements of poly(dodecyl acrylate). Numerical modeling demonstrated that significant flows would arise for conditions corresponding to the planned experiments.

Pojman, John A.↗
NASA NTRS2004

The impact of organizational structure on flight software cost risk

This paper summarizes the final results of the follow-up study updating the estimated software effort growth for those projects that were still under development and including an evaluation of the roles versus observed cost risk for the missions included in the original study which expands the data set to thirteen missions.

software cost↗
NASA NTRS2006

Software Development Cost: How Much? You Sure? Technical Summary

This slide presentation reports on findings from analyzing a NASA COCOMO 81 dataset with 93 records. The current tool is called COSEEKMO, using a methodology can be applied to any set of cost models and data. The effort was part of a research initiative funded by the NASA Office of Safety and Mission and Assurance (OSMA) aimed at improving software reliability.

software effort estimation↗