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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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NASA NTRS1995

NASA/DOD Aerospace Knowledge Diffusion Research Project. Paper 51: Workplace communications skills and the value of communications and information-use skills instruction: Engineering students' perspectives

Studies indicate that communications and information-related activities take up a substantial portion of an engineer's work week; therefore, effective communications and information use skills are one of the key engineering competencies that recent graduates of engineering programs are expected to possess. Feedback from industry rates communications and information use skills of entry-level engineers low. Missing from current discussions of communications and information use skills and competencies for engineering students is a clear explanation from the professional engineering community about what constitutes 'acceptable and desirable communications and information norms' within that community. To gather adequate and generalizable data about communications and information skills instruction and to provide a student perspective on the communications skills of engineers, we undertook a national study of aerospace engineering students in March 1993. The study included questions about the importance of certain communications and information skills to professional success, the instruction students had received in these skills, and perceived helpfulness of the instruction. Selected results from the study study are reported in this paper.

Pinelli, Thomas E.↗
NASA NTRS1995

A design perspective on thermal barrier coatings

This technical paper addresses the challenges for maximizing the benefit of thermal barrier coatings for turbine engine applications. The perspective is from a customer's viewpoint, a turbine airfoil designer, who is continuously challenged to increase the turbine inlet temperature capability for new products while maintaining cooling flow levels or even reducing them. This is a fundamental requirement to achieve increased engine thrust levels. Developing advanced material systems for the turbine flowpath airfoils is one approach to solve this challenge; such as high temperature nickel based superalloys or thermal barrier coatings to insulate the metal airfoils from the hot flowpath environment. The second approach is to increase the cooling performance of the turbine airfoil, which enables increased flowpath temperatures and reduced cooling flow levels. Thermal barrier coatings have been employed in jet engine applications for almost 30 years. The initial application was on augmentor liners to provide thermal protection during afterburner operation. However, the production use of thermal barrier coating in the turbine section has only occurred in the past 15 years. The application was limited to stationary parts, and only recently incorporated on the rotating turbine blades. This lack of endorsement of thermal barrier coatings resulted from the poor initial durability of these coatings in high heat flux environments. Significant improvements have been made to enhance spallation resistance and erosion resistance which has resulted in increased reliability of these coatings in turbine applications.

Soechting, Friedrich O.↗
NASA NTRS1995

Perspective on thermal barrier coatings for industrial gas turbine applications

Thermal barrier coatings (TBC's) have been used in high thrust aircraft engines for many years, and have proved to be very effective in providing thermal protection and increasing engine efficiencies. TBC life requirements for aircraft engines are typically less than those required for industrial gas turbines. This paper describes current and future applications of TBC's in industrial gas turbine engines. Early testing and applications of TBC's is reviewed. Areas of concern from the engine designer's and materials engineer's perspective are identified and evaluated. This paper focuses on the key factors that are expected to influence utilization of TBC's in advanced industrial gas turbine engines. It is anticipated that reliable, durable and highly effective coating systems will be produced that will ultimately improve engine efficiency and performance.

Mutasim, Zaher↗
NASA NTRS1995

Sustaining Space Systems for Strategic and Theater Operations: A Study Perspective

Our Desert Storm experience in the tactical utility of DoD space vehicles demonstrated that DoD's investment in space technology can provide a significant military advantage during times of crisis and war. The satellites what gave us such marvelous intelligence in locating, tracking, and enabling the successful attack of key targets resulted in a spectacular military success. However, without an on-orbit servicing capability, the fuel consumed to maneuver these satellites into position over the battlefield shortened their useful life by as much as two years. During the 1970's and 1980's, the Air Force aggressively pursued an or-orbit support capability to support and maintain it's space-based assets. However, in the early 1990's, budgetary and political priorities canceled the programs that would have made this a reality. Realizing that a future decision may be made to re-investigate on-orbit support, the United States Space Command (USSPACECOM) sponsored a study to document efforts undertaken by the Air Force during the 1970's and 1980's in developing strategies and actions to achieve certain tenets of on-orbit support. The study represents an attempt to gather, review, summarize, and archive the most important research performed during this period. It will serve as a historical perspective upon which to base future research and development activities. This paper presents an overview of that study.

McCoy, Walbert↗
NASA NTRS1998

Firsthand Perspective on the Microgravity Environment

Extended periods of microgravity simply cannot be created on Earth and rely on orbiting spacecraft in low earth orbit. These low microgravity levels are one of the most critical resources for most experiments being conducted aboard the space shuttle and those proposed for the International Space Station. A second critical resource for successfully conducting many of these experiments in space is the presence of human beings. Trained mission specialists and payload specialists become the eyes and ears of the scientists on the ground. In their function as in-flight technicians and "observers" they are important for reporting first hand the progress of the experiments, as well as being on call to trouble shoot malfunctioning equipment and, make necessary repairs. Unfortunately, as important as astronauts are to the successful performance of many experiments, they can be in conflict with the first goal of achieving as pristine a microgravity environment as possible. A simple astronaut sneeze has been calculated to induce a perturbation of 10(exp -5) g which may adversely affect some of the more sensitive experiments. A first hand perspective of what it is like to work in this environment and ways crewmembers can work more effectively to minimize disturbances will be discussed as well as ways that the ground can assist crewmembers to protect the microgravity environment.

Thomas, Donald A.↗
NASA NTRS1996

An Open Computing Infrastructure that Facilitates Integrated Product and Process Development from a Decision-Based Perspective

Computer applications for design have evolved rapidly over the past several decades, and significant payoffs are being achieved by organizations through reductions in design cycle times. These applications are overwhelmed by the requirements imposed during complex, open engineering systems design. Organizations are faced with a number of different methodologies, numerous legacy disciplinary tools, and a very large amount of data. Yet they are also faced with few interdisciplinary tools for design collaboration or methods for achieving the revolutionary product designs required to maintain a competitive advantage in the future. These organizations are looking for a software infrastructure that integrates current corporate design practices with newer simulation and solution techniques. Such an infrastructure must be robust to changes in both corporate needs and enabling technologies. In addition, this infrastructure must be user-friendly, modular and scalable. This need is the motivation for the research described in this dissertation. The research is focused on the development of an open computing infrastructure that facilitates product and process design. In addition, this research explicitly deals with human interactions during design through a model that focuses on the role of a designer as that of decision-maker. The research perspective here is taken from that of design as a discipline with a focus on Decision-Based Design, Theory of Languages, Information Science, and Integration Technology. Given this background, a Model of IPPD is developed and implemented along the lines of a traditional experimental procedure: with the steps of establishing context, formalizing a theory, building an apparatus, conducting an experiment, reviewing results, and providing recommendations. Based on this Model, Design Processes and Specification can be explored in a structured and implementable architecture. An architecture for exploring design called DREAMS (Developing Robust Engineering Analysis Models and Specifications) has been developed which supports the activities of both meta-design and actual design execution. This is accomplished through a systematic process which is comprised of the stages of Formulation, Translation, and Evaluation. During this process, elements from a Design Specification are integrated into Design Processes. In addition, a software infrastructure was developed and is called IMAGE (Intelligent Multidisciplinary Aircraft Generation Environment). This represents a virtual apparatus in the Design Experiment conducted in this research. IMAGE is an innovative architecture because it explicitly supports design-related activities. This is accomplished through a GUI driven and Agent-based implementation of DREAMS. A HSCT design has been adopted from the Framework for Interdisciplinary Design Optimization (FIDO) and is implemented in IMAGE. This problem shows how Design Processes and Specification interact in a design system. In addition, the problem utilizes two different solution models concurrently: optimal and satisfying. The satisfying model allows for more design flexibility and allows a designer to maintain design freedom. As a result of following this experimental procedure, this infrastructure is an open system that it is robust to changes in both corporate needs and computer technologies. The development of this infrastructure leads to a number of significant intellectual contributions: 1) A new approach to implementing IPPD with the aid of a computer; 2) A formal Design Experiment; 3) A combined Process and Specification architecture that is language-based; 4) An infrastructure for exploring design; 5) An integration strategy for implementing computer resources; and 6) A seamless modeling language. The need for these contributions is emphasized by the demand by industry and government agencies for the development of these technologies.

Hale, Mark A.↗
NASA NTRS1995

On Developing a Taxonomy for Multidisciplinary Design Optimization: A Decision-Based Perspective

In this paper, we approach MDO from a Decision-Based Design (DBD) perspective and explore classification schemes for designing complex systems and processes. Specifically, we focus on decisions, which are only a small portion of the Decision Support Problem (DSP) Technique, our implementation of DBD. We map coupled nonhierarchical and hierarchical representations from the DSP Technique into the Balling-Sobieski (B-S) framework (Balling and Sobieszczanski-Sobieski, 1994), and integrate domain-independent linguistic terms to complete our taxonomy. Application of DSPs to the design of complex, multidisciplinary systems include passenger aircraft, ships, damage tolerant structural and mechanical systems, and thermal energy systems. In this paper we show that Balling-Sobieski framework is consistent with that of the Decision Support Problem Technique through the use of linguistic entities to describe the same type of formulations. We show that the underlying linguistics of the solution approaches are the same and can be coalesced into a homogeneous framework with which to base the research, application, and technology MDO upon. We introduce, in the Balling-Sobieski framework, examples of multidisciplinary design, namely, aircraft, damage tolerant structural and mechanical systems, and thermal energy systems.

Lewis, Kemper↗
NASA NTRS1998

Martian Polar Region Impact Craters: Topographical Perspectives from the Mars Orbiter Laser Altimeter

The Mars Orbiter Laser Altimeter (MOLA) has acquired over 100 topographic cross-sections of impact landforms in the polar regions of Mars as part of Mars Global Surveyor (MGS) Science Phasing Orbit observations during the period from April to July, 1998. These MOLA topographic profiles offer the first three-dimensional perspectives of high latitude craters on Mars yet available, and provide evidence of landform geometries not previously recognized. Indeed, the relatively poor quality of Viking Orbiter images of many high northern latitude regions has allowed the MOLA data to provide insights into the cavities and ejecta topologies of non-degraded impact landforms that have clearly experienced interactions with condensates, either as part of their formation, or as a post-modification stage effect. Here we report a preliminary summary of the results associated with topographic measurements for a statistically significant population of impact features all of which lie north of 60N latitude. MOLA sampled four impact features with frost-related interior deposits, including the 81 km (diameter) Korolev feature. In several cases, there is evidence from near-centerline MOLA cross-sections of crater interior features (i.e., central peak or ice-dust deposits) that are anomalously large relative to the crater cavity. Central structures that make up more than 50% of the volume of a crater cavity are observed, suggesting that either substantial accumulation of mantling materials has occurred, or that crater excavation triggered production of volume-enhancing materials (ice?). Pedestal craters sampled by MOLA also attest to enhanced production of ejecta materials in high latitude terrains. For example, many of the pedestal craters suggest a volume of ejecta (Ve) to volume of cavity (Vc) ratio far in excess of 1.0 (i.e., over 3.0), even in cases where the floor of the cavity appears unfilled. Finally, the well-defined transitions between simple and complex craters observed in MOLA data for non-polar latitude impact features is not preserved at high northern latitudes (for non-degraded craters). This further suggests the role of target materials (i.e., frozen volatiles?) in the cratering process on Mars in such regions.

Garvin, J. B.↗
NASA NTRS2000

The Fight Deck Perspective of the NASA Langley AILS Concept

Many US airports depend on parallel runway operations to meet the growing demand for day to day operations. In the current airspace system, Instrument Meteorological Conditions (IMC) reduce the capacity of close parallel runway operations; that is, runways spaced closer than 4300 ft. These capacity losses can result in landing delays causing inconveniences to the traveling public, interruptions in commerce, and increased operating costs to the airlines. This document presents the flight deck perspective component of the Airborne Information for Lateral Spacing (AILS) approaches to close parallel runways in IMC. It represents the ideas the NASA Langley Research Center (LaRC) AILS Development Team envisions to integrate a number of components and procedures into a workable system for conducting close parallel runway approaches. An initial documentation of the aspects of this concept was sponsored by LaRC and completed in 1996. Since that time a number of the aspects have evolved to a more mature state. This paper is an update of the earlier documentation.

Rine, Laura L.↗
NASA NTRS1999

Highlights of Recent Developments in the International GPS Service and Perspectives for Future Directions

In December 1998, the IGS Governing Board officially changed the name of this IAG service from 'International GPS Service for Geodynamics to simply the 'International GPS Service'. This change of name reflects the fact that today the IGS supports numerous scientific projects outside the traditional geodetic and geodynamic disciplines. A number of IGS projects and working groups have been established, each concentrating on a particular science application, such as the ionosphere, atmosphere, reference frame, precise time transfer, etc. These activities are enabled and simulated by the IGS and directly contribute to the continuing development of the service. The IGS is currently poised to respond to evolving user requirements that focus on timeliness and reliability of data and products, particularly in support of a slate of Low Earth Orbiter missions over the next decade. Perspectives on the future of the IGS will be developed based on current directions as well as anticipated external influences, such as GPS satellite modernization, GLONASS, availability of global communications, and plans for the European GALILEO (Global Navigation Satellite System - GNSS). We will address development of user friendly interfaces and IGS product tutorials.

Neilan, R.↗
NASA NTRS2000

Origin of the Valley Networks On Mars: A Hydrological Perspective

The geomorphology of the Martian valley networks is examined from a hydrological perspective for their compatibility with an origin by rainfall, globally higher heat flow, and localized hydrothermal systems. Comparison of morphology and spatial distribution of valleys on geologic surfaces with terrestrial fluvial valleys suggests that most Martian valleys are probably not indicative of a rainfall origin, nor are they indicative of formation by an early global uniformly higher heat flow. In general, valleys are not uniformly distributed within geologic surface units as are terrestrial fluvial valleys. Valleys tend to form either as isolated systems or in clusters on a geologic surface unit leaving large expanses of the unit virtually untouched by erosion. With the exception of fluvial valleys on some volcanoes, most Martian valleys exhibit a sapping morphology and do not appear to have formed along with those that exhibit a runoff morphology. In contrast, terrestrial sapping valleys form from and along with runoff valleys. The isolated or clustered distribution of valleys suggests localized water sources were important in drainage development. Persistent ground-water outflow driven by localized, but vigorous hydrothermal circulation associated with magmatism, volcanism, impacts, or tectonism is, however, consistent with valley morphology and distribution. Snowfall from sublimating ice-covered lakes or seas may have provided an atmospheric water source for the formation of some valleys in regions where the surface is easily eroded and where localized geothermal/hydrothermal activity is sufficient to melt accumulated snowpacks.

Gulick, Virginia C.↗
NASA NTRS2001

Narragansett Bay From Space: A Perspective for the 21st Century

In 1996, the NASA Administrator Dan Goldin and Rhode Island Congressman Patrick Kennedy challenged researchers in the Department of Geological Sciences at Brown University to developed a series of projects to apply remotely sensed data to problems of immediate concern to the State of Rhode Island. The result of that challenge was the project Narragansett Bay from Space: A Perspective for the 21st Century. The goals of the effort were to a) identify problems in coordination with state and local agencies, b) apply NASA technology to the problems and c) to involve small business that would benefit from incorporating remotely sensed data into their business operations. The overall effort was to serve two functions: help provide high quality science results based on remotely sensed data and increase the capacity of environmental managers and companies to use remotely sensed data. The effort has succeeded on both these fronts by providing new, quantitative information on the extent of environmental problems and developing a greater awareness and acceptance of remotely sensed data as a tool for monitoring and research.

Mustard, John F.↗
NASA NTRS2001

Turbulence Modeling: A NASA Perspective

This paper presents turbulence modeling from NASA's perspective. The topics include: 1) Hierarchy of Solution Methods; 2) Turbulence Modeling Focus; 3) Linear Eddy Viscosity Models; and 4) Nonlinear Eddy Viscosity Algebraic Stress Models.

Gatski, T. B.↗
NASA NTRS2001

Investigating Uncertainty in Predicting Carbon Dynamics in North American Biomes: Putting Support-Effect Bias in Perspective

A fundamental strategy in NASA's Earth Observing System's (EOS) monitoring of vegetation and its contribution to the global carbon cycle is to rely on deterministic, process-based ecosystem models to make predictions of carbon flux over large regions. These models are parameterized (that is, the input variables are derived) using remotely sensed images such as those from the Moderate Resolution Imaging Spectroradiometer (MODIS), ground measurements and interpolated maps. Since early applications of these models, investigators have noted that results depend partly on the spatial support of the input variables. In general, the larger the support of the input data, the greater the chance that the effects of important components of the ecosystem will be averaged out. A review of previous work shows that using large supports can cause either positive or negative bias in carbon flux predictions. To put the magnitude and direction of these biases in perspective, we must quantify the range of uncertainty on our best measurements of carbon-related variables made on equivalent areas. In other words, support-effect bias should be placed in the context of prediction uncertainty from other sources. If the range of uncertainty at the smallest support is less than the support-effect bias, more research emphasis should probably be placed on support sizes that are intermediate between those of field measurements and MODIS. If the uncertainty range at the smallest support is larger than the support-effect bias, the accuracy of MODIS-based predictions will be difficult to quantify and more emphasis should be placed on field-scale characterization and sampling. This talk will describe methods to address these issues using a field measurement campaign in North America and "upscaling" using geostatistical estimation and simulation.

Dungan, Jennifer L.↗
NASA NTRS2001

Solid and Gas-Phase Spectroscopy of Cosmic Carbon Analogs: Results and Perspectives

The laboratory studies of interstellar carbon materials analogs (PAHs, Fullerenes, chains) will be discussed with their advantages and limitations from the point of view of the application to astrophysical processes. The discussion will focus on the newest generation of laboratory experiments that has been developed in order to provide a closer simulation of space environments and a better support to space missions. The astrophysical implications and future perspectives will be stressed.

Salama, Farid↗
NASA NTRS2001

Loop Heat Pipes and Capillary Pumped Loops: An Applications Perspective

Capillary pumped loops (CPLS) and loop heat pipes (LHPS) are versatile two-phase heat transfer devices which have recently gained increasing acceptance in space applications. Both systems work based on the same principles and have very similar designs. Nevertheless, some differences exist in the construction of the evaporator and the hydro-accumulator, and these differences lead to very distinct operating characteristics for each loop. This paper presents comparisons of the two loops from an applications perspective, and addresses their impact on spacecraft design, integration, and test. Some technical challenges and issues for both loops are also addressed.

Butler, Dan↗
NASA NTRS2001

Spectroscopy of Cosmic Carbon Analogs in Inert-Gas Matrices and in the Gas-Phase: Comparative Results and Perspectives for Astrophysics

Recent studies of the spectroscopy of large (up to approx. 50 carbon atoms) neutral and Ionized polycyclic aromatic hydrocarbons (PAHs) and Fullerenes isolated in inert gas matrices will be presented. The advantages and the limitations of matrix isolation spectroscopy for the study of the molecular spectroscopy of interstellar dust analogs will be discussed. The laboratory data will be compared to the astronomical spectra (the interstellar extinction, the diffuse interstellar bands). Finally, the spectra of PAH ions isolated in neon/argon matrices will be compared to the spectra obtained for PAH ion seeded in a supersonic expansion. The astrophysical implications and future perspectives will be discussed.

Salama, Farid↗
NASA NTRS1995

Training for Aviation Decision Making: The Naturalistic Decision Making Perspective

This paper describes the implications of a naturalistic decision making (NDM) perspective for training air crews to make flight-related decisions. The implications are based on two types of analyses: (a) identification of distinctive features that serve as a basis for classifying a diverse set of decision events actually encountered by flight crews, and (b) performance strategies that distinguished more from less effective crews flying full-mission simulators, as well as performance analyses from NTSB accident investigations. Six training recommendations are offered: (1) Because of the diversity of decision situations, crews need to be aware that different strategies may be appropriate for different problems; (2) Given that situation assessment is essential to making a good decision, it is important to train specific content knowledge needed to recognize critical conditions, to assess risks and available time, and to develop strategies to verify or diagnose the problem; (3) Tendencies to oversimplify problems may be overcome by training to evaluate options in terms of goals, constraints, consequences, and prevailing conditions; (4) In order to provide the time to gather information and consider options, it is essential to manage the situation, which includes managing crew workload, prioritizing tasks, contingency planning, buying time (e.g., requesting holding or vectors), and using low workload periods to prepare for high workload; (5) Evaluating resource requirements ("What do I need?") and capabilities ("'What do I have?" ) are essential to making good decisions. Using resources to meet requirements may involve the cabin crew, ATC, dispatchers, and maintenance personnel; (6) Given that decisions must often be made under high risk, time pressure, and workload, train under realistic flight conditions to promote the development of robust decision skills.

Orasanu, Judith↗