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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 451 records · Page 25
All sourcesNASA NTRSDOE OSTI
NASA NTRS2005

Three-Dimensional Audio Client Library

The Three-Dimensional Audio Client Library (3DAudio library) is a group of software routines written to facilitate development of both stand-alone (audio only) and immersive virtual-reality application programs that utilize three-dimensional audio displays. The library is intended to enable the development of three-dimensional audio client application programs by use of a code base common to multiple audio server computers. The 3DAudio library calls vendor-specific audio client libraries and currently supports the AuSIM Gold-Server and Lake Huron audio servers. 3DAudio library routines contain common functions for (1) initiation and termination of a client/audio server session, (2) configuration-file input, (3) positioning functions, (4) coordinate transformations, (5) audio transport functions, (6) rendering functions, (7) debugging functions, and (8) event-list-sequencing functions. The 3DAudio software is written in the C++ programming language and currently operates under the Linux, IRIX, and Windows operating systems.

Rizzi, Stephen A.↗
NASA NTRS1993

Robust nonlinear control of vectored thrust aircraft

An interdisciplinary program in robust control for nonlinear systems with applications to a variety of engineering problems is outlined. Major emphasis will be placed on flight control, with both experimental and analytical studies. This program builds on recent new results in control theory for stability, stabilization, robust stability, robust performance, synthesis, and model reduction in a unified framework using Linear Fractional Transformations (LFT's), Linear Matrix Inequalities (LMI's), and the structured singular value micron. Most of these new advances have been accomplished by the Caltech controls group independently or in collaboration with researchers in other institutions. These recent results offer a new and remarkably unified framework for all aspects of robust control, but what is particularly important for this program is that they also have important implications for system identification and control of nonlinear systems. This combines well with Caltech's expertise in nonlinear control theory, both in geometric methods and methods for systems with constraints and saturations.

Doyle, John C.↗
NASA NTRS2009

Early Career Hire Rapid Training and Development Program: Status Report

The aging of the industrialized workforce, particularly in the aerospace industry, has resulted in a very large generation gap in the workforce. The disproportionate size of Baby Boomers, increasing longevity and declining birth rates has made this phenomenon a reality that no organization can ignore. It is now critical that aerospace organizations prepare themselves for this watershed transformation in the workforce and take the initiative to prepare the incoming workforce with the skills and knowledge necessary to stay at the forefront. Last year the Jet Propulsion Laboratory launched a pioneering training program, known as Phaeton, to provide the knowledge, practice, experience, mentoring opportunities, and project life cycle exposure to our incoming generation of engineers. After 14 months of operation, now is the time to discuss the preliminary results of this new program.

Riley, Betsy N.↗
NASA NTRS1973

A review of the technology of noncontacting systems

Advanced components are the fundamental building blocks of advanced systems and spacecraft. Non-contacting elements, including magnetic bearings, brushless and ironless armature motors, rotary transformers and encoders, are discussed. Most of the information presented in this paper has been generated from a continuing program of component development. The aim of this paper is to identify some of the important design features and provide a perspective on the state of development reached to date.

Studer, P. A.↗
NASA NTRS1976

Effects of selected R&D options on fuel usage in the commercial air system

The study on which this paper is based, known as RECAT (Study of Cost Benefit Tradeoffs for Reducing the Energy Consumption of the Commercial Air Transportation System), was sponsored by NASA to establish a basis for assigning priorities in its aircraft fuel-conservation R&D program. The study involved coordinated efforts by four independent contractors to conceive and quantify fuel-conserving technology alternatives, transform these alternatives into viable R&D options, and simulate each option in a general model of the U.S. domestic air transportation system. This paper deals primarily with the latter phase and concentrates on the results of the study, as revealed not only by estimated fuel usage but also by other impacts of the technology options, such as demand growth, operator economics, and fleet composition. However, while the paper focuses on results, the basic assumptions and technology inputs are documented, and a general description of the modeling approach is provided to demonstrate the level of detail considered in the analysis.

Gobetz, F. W.↗
NASA NTRS1982

Map projections for larger-scale mapping

For the U.S. Geological Survey maps at 1:1,000,000-scale and larger, the most common projections are conformal, such as the Transverse Mercator and Lambert Conformal Conic. Projections for these scales should treat the Earth as an ellipsoid. In addition, the USGS has conceived and designed some new projections, including the Space Oblique Mercator, the first map projection designed to permit low-distortion mapping of the Earth from satellite imagery, continuously following the groundtrack. The USGS has programmed nearly all pertinent projection equations for inverse and forward calculations. These are used to plot maps or to transform coordinates from one projection to another. The projections in current use are described.

Snyder, J. P.↗
NASA NTRS1984

Evaluation of the solar disk sextant concept

In this paper the viability of the solar disk sextant concept is evaluated, the optimum parameters required to carry out solar variability studies, which are the mission objectives, are derived. The experimental environment is first discussed, followed by the application of the finite Fourier transform definition (FFTD) to the detector array data. The requirements on the optical system are studied next. A computer program was carried out simulating solar edge data and FFTD. From this study, it is concluded that the required accuracy of measurement may be reached using currently available detector array technology, a focal ratio of the optical system in excess of 90, and an entrance aperture of 22 cm. The guidance error must be small enough to require no more than a correction rate of 0.1 arcsec/sec. All these conditions are well within current technology.

Chiu, H.-Y.↗
NASA NTRS1985

Data handling and data flow design and their application in the space telescope guide star selection system

The data formats and data encapsulation techniques used in the Space Telescope Guide Star Selection System (GSSS) are described. Emphasis is given to the use of image field and object list transformation to organize and refine high-levels of data flow from Space Telescope. The application of the Ada programming language to data encapsulation techniques is discussed in detail.

Rosenthal, D. A.↗
NASA NTRS1995

Nonlinear viscoelastic characterization of polymer materials using a dynamic-mechanical methodology

Polymer materials retrieved from LDEF exhibit nonlinear constitutive behavior; thus the authors present a method to characterize nonlinear viscoelastic behavior using measurements from dynamic (oscillatory) mechanical tests. Frequency-derived measurements are transformed into time-domain properties providing the capability to predict long term material performance without a lengthy experimentation program. Results are presented for thin-film high-performance polymer materials used in the fabrication of high-altitude scientific balloons. Predictions based upon a linear test and analysis approach are shown to deteriorate for moderate to high stress levels expected for extended applications. Tests verify that nonlinear viscoelastic response is induced by large stresses. Hence, an approach is developed in which the stress-dependent behavior is examined in a manner analogous to modeling temperature-dependent behavior with time-temperature correspondence and superposition principles. The development leads to time-stress correspondence and superposition of measurements obtained through dynamic mechanical tests. Predictions of material behavior using measurements based upon linear and nonlinear approaches are compared with experimental results obtained from traditional creep tests. Excellent agreement is shown for the nonlinear model.

Strganac, Thomas W.↗
NASA NTRS1987

Design and evaluation of executable assertions for concurrent error detection

System level concurrent detection of errors due to hardware faults can be accomplished by introducing software redundancy in the form of executable assertions into a program to monitor the correct operation of the system during its execution. This paper attempts to formalize the use of executable assertions for the purpose of concurrent error detection, and discusses a transformation approach to the design of assertion statements. The second part deals with the effectiveness of the error detection technique. A fault simulation method for the evaluation of the reliability of the assertion statements is described. This scheme was used to study the effectiveness of a nontrivial program in providing protection against faults in the underlying system. The experimental results shows that the use of executable assertions provides an effective approach to achieve concurrent error detection.

Hua, Kien A.↗
NASA NTRS2022

Expansion of Existing Research and Analysis Programs

Small-grants programs play a vital role in Heliophysics research. They are a modest investment with a huge scientific payoff. Frequently, it is individuals and small research groups funded by small grants that make the high-innovation breakthroughs that have such a transformative impact on a field. Small grants also give most early-career researchers their first experience as principal investigator – experience they need to eventually become leaders in their field. We therefore recommend that existing NASA programs like Heliophysics Supporting Research (HSR), Heliophysics Guest Investigator (HGI), and Heliophysics Technology and Instrument Development for Science (HTIDeS) be greatly expanded. We also recommend that funding opportunities be created for mid-size grants, $500-1000K/yr, either as part of existing programs or with new programs dedicated to this size.

James A. Klimchuk↗
NASA NTRSDate not supplied

How the Open Data Policy of the Landsat Program Has Advanced Our Understanding of Environmental Change

A time series is a sequence of observations of a phenomenon taken sequentially in time. A crucial characteristic of a time series is the dependence among adjacent observations – techniques for analyzing this dependence are referred to as time series analysis. This analytical approach enables us to predict or forecast future values of a time series, study the impact of various inputs on the observed phenomenon, and examine interrelationships among related time series variables. Within the geographical sciences, time series analysis has historically been limited to coarse-resolution satellite data, as constructing time series of data suitable for studying land cover and land use dynamics, such as Landsat data, were prohibitively costly. A transformative shift occurred in 2008 when the U.S. Government decided to make free and open all past and future data collected by the Landsat satellite program. The decision brought about a paradigm shift away from analyzing individual images or observations to continuous monitoring in time. Of particular relevance to environmental remote sensing is the ability to forecast observations – if we can predict how future observations should behave, we can infer information about how the land surface is changing. In this presentation, we will examine literature examples that showcase scientific gains enabled by time series analysis of satellite data. We will delve into how the analysis of dense time series of satellite data revealed that overall rate of forest disturbance in the Amazon has increased despite a reduction in deforestation; how different types of forest degradation, previously unquantified, are now being accurately assessed in the Caucasus region; and how we now can study the highly dynamic and intricate patterns of shifting cultivation in Southeast Asia.

Pontus Olofsson↗
NASA NTRS1996

DNA damage and repair in oncogenic transformation by heavy ion radiation

Energetic heavy ions are present in galactic cosmic rays and solar particle events. One of the most important late effects in risk assessment is carcinogenesis. We have studied the carcinogenic effects of heavy ions at the cellular and molecular levels and have obtained quantitative data on dose-response curves and on the repair of oncogenic lesions for heavy particles with various charges and energies. Studies with repair inhibitors and restriction endonucleases indicated that for oncogenic transformation DNA is the primary target. Results from heavy ion experiments showed that the cross section increased with LET and reached a maximum value of about 0.02 micrometer2 at about 500 keV/micrometer. This limited size of cross section suggests that only a fraction of cellular genomic DNA is important in radiogenic transformation. Free radical scavengers, such as DMSO, do not give any effect on induction of oncogenic transformation by 600 MeV/u iron particles, suggesting most oncogenic damage induced by high-LET heavy ions is through direct action. Repair studies with stationary phase cells showed that the amount of reparable oncogenic lesions decreased with an increase of LET and that heavy ions with LET greater than 200 keV/micrometer produced only irreparable oncogenic damage. An enhancement effect for oncogenic transformation was observed in cells irradiated by low-dose-rate argon ions (400 MeV/u; 120 keV/micrometer). Chromosomal aberrations, such as translocation and deletion, but not sister chromatid exchange, are essential for heavy-ion-induced oncogenic transformation. The basic mechanism(s) of misrepair of DNA damage, which form oncogenic lesions, is unknown.

NASA Discipline Number 45-10↗
NASA NTRS1990

Light weight, high power, high voltage dc/dc converter technologies

Power-conditioning weight reductions by orders of magnitude will be required to enable the megawatt-power-level space systems envisioned by the Strategic Defense Initiative, the Air Force, and NASA. An interagency program has been initiated to develop an 0.1-kg/kW dc/dc converter technology base for these future space applications. Three contractors are in the first phase of a competitive program to develop a megawatt dc/dc converter. Researchers at NASA Lewis Research Center are investigating innovative converter topology control. Three different converter subsystems based on square wave, resonant, and super-resonant topologies are being designed. The components required for the converter designs cover a wide array of technologies. Two different switches, one semiconductor and the other gas, are under development. Issues related to thermal management and material reliability for inductors, transformers, and capacitors are being investigated in order to maximize power density. A brief description of each of the concepts proposed to meet the goals of this program is presented.

Kraus, Robert↗
NASA NTRS1996

A Computer Program for the Computation of Running Gear Temperatures Using Green's Function

A new technique has been developed to study two dimensional heat transfer problems in gears. This technique consists of transforming the heat equation into a line integral equation with the use of Green's theorem. The equation is then expressed in terms of eigenfunctions that satisfy the Helmholtz equation, and their corresponding eigenvalues for an arbitrarily shaped region of interest. The eigenfunction are obtalned by solving an intergral equation. Once the eigenfunctions are found, the temperature is expanded in terms of the eigenfunctions with unknown time dependent coefficients that can be solved by using Runge Kutta methods. The time integration is extremely efficient. Therefore, any changes in the time dependent coefficients or source terms in the boundary conditions do not impose a great computational burden on the user. The method is demonstrated by applying it to a sample gear tooth. Temperature histories at representative surface locatons are given.

GREENS FUNCTIONS↗
NASA NTRS1992

Chromosomal changes in cultured human epithelial cells transformed by low- and high-LET radiation

For a better assessment of radiation risk in space, an understanding of the responses of human cells, especially the epithelial cells, to low- and high-LET radiation is essential. In our laboratory, we have successfully developed techniques to study the neoplastic transformation of two human epithelial cell systems by ionizing radiation. These cell systems are human mammary epithelial cells (H184B5) and human epidermal keratinocytes (HEK). Both cell lines are immortal, anchorage dependent for growth, and nontumorigenic in athymic nude mice. Neoplastic transformation was achieved by irradiating cells successively. Our results showed that radiogenic cell transformation is a multistep process and that a single exposure of ionizing radiation can cause only one step of transformation. It requires, therefore, multihits to make human epithelial cells fully tumorigenic. Using a simple karyotyping method, we did chromosome analysis with cells cloned at various stages of transformation. We found no consistent large terminal deletion of chromosomes in radiation-induced transformants. Some changes of total number of chromosomes, however, were observed in the transformed cells. These transformants provide an unique opportunity for further genetic studies at a molecular level.

NASA Discipline Number 04-10↗
NASA NTRS2004

Intelligent Systems Technologies and Utilization of Earth Observation Data

The addition of raw data and derived geophysical parameters from several Earth observing satellites over the last decade to the data held by NASA data centers has created a data rich environment for the Earth science research and applications communities. The data products are being distributed to a large and diverse community of users. Due to advances in computational hardware, networks and communications, information management and software technologies, significant progress has been made in the last decade in archiving and providing data to users. However, to realize the full potential of the growing data archives, further progress is necessary in the transformation of data into information, and information into knowledge that can be used in particular applications. Sponsored by NASA s Intelligent Systems Project within the Computing, Information and Communication Technology (CICT) Program, a conceptual architecture study has been conducted to examine ideas to improve data utilization through the addition of intelligence into the archives in the context of an overall knowledge building system (KBS). Potential Intelligent Archive concepts include: 1) Mining archived data holdings to improve metadata to facilitate data access and usability; 2) Building intelligence about transformations on data, information, knowledge, and accompanying services; 3) Recognizing the value of results, indexing and formatting them for easy access; 4) Interacting as a cooperative node in a web of distributed systems to perform knowledge building; and 5) Being aware of other nodes in the KBS, participating in open systems interfaces and protocols for virtualization, and achieving collaborative interoperability.

Ramapriyan, H. K.↗
DOE OSTI2024

Curating Carbon Storage Data for Reuse: Enabling Research and Modeling from Earth’s Surface to Subsurface

The volume of public geologic carbon storage (GCS) data resources has continued to increase in recent years as the result of an increase in funding from government, industry, and academia towards national, basin, regional and field scale studies to ensure carbon capture and storage becomes a commercially viable operation. Despite the increasing volume of data, GCS data applied towards analyses such as geologic, cost, and risk modeling continues to be multi-sourced and often disparate in nature, published across government agencies, websites, data repositories and buried in derivative reports and documents. Much of the time preparing for an analysis and derivative product development is spent collecting, aggregating, transforming and preparing input data. There have been significant efforts within the DOE National Energy Technology Laboratory’s Carbon Storage Program to optimize multi-source, multi-scale subsurface geologic data curation and aggregation to support data discovery, interoperability, and reuse. Methods include the use of artificial intelligence, machine learning, and data science techniques. This talk will discuss the workflows, best practices, and processes developed to support the aggregation and curation of data through the whole system – surface to subsurface data - that support multi-scale, multi-purpose analysis for carbon storage research.

Morkner, Paige↗