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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 469 records · Page 26
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

A display evaluation methodology applied to vertical situation displays

An approach to display evaluation based on the optimal-control or state-variable model of the human operator is described. The approach evolved over the past several years, and is believed to have significant advantages for display evaluation. The foundations of the methodology are briefly described, and results are presented of its application to the analysis of vertical situation displays for STOL approach. This analysis includes the effects of both status and command displays on pilot workload and system performance.

Baron, S.↗
NASA NTRS1974

Power processing methodology

Discussion of the interim results of a program to investigate the feasibility of formulating a methodology for the modeling and analysis of aerospace electrical power processing systems. The object of the total program is to develop a flexible engineering tool which will allow the power processor designer to effectively and rapidly assess and analyze the tradeoffs available by providing, in one comprehensive program, a mathematical model, an analysis of expected performance, simulation, and a comparative evaluation with alternative designs. This requires an understanding of electrical power source characteristics and the effects of load control, protection, and total system interaction.

Fegley, K. A.↗
NASA NTRS1975

Technology and methodology of separating two similar size aerospace vehicles within the atmosphere

During the past 10 years, the parallel separation, within the atmosphere, of two similar size aerospace vehicles has been investigated in technical areas such as static and dynamic stability, rocket exhaust plume interference, aerodynamic control, loads, and dynamic simulation. Advanced experimental and analysis techniques have been developed to analyze this problem. Results are presented which summarize some of this work. The effects of various parameters on the separation maneuver are illustrated using results from early and current space shuttle configurations. The technology and methodology that have been developed have helped verify the feasibility of separating similar size aerospace vehicles.

Decker, J. P.↗
NASA NTRS1975

ECASTAR methodology

The methodology used for the ECASTAR study was described. A systems approach was utilized, in conjunction with the following tools: input/output economic analysis, net economics, and net energetics. Some of the considerations between the objective of ECASTAR, which is to assess the potential for and impacts of various energy conservation actions, were listed. These include: data base, constraints and criteria, identification and classification of energy conservation actions, relationship between actions of the conservation sector and requirements of other sectors, evaluation of actions with respect to constraints and criteria, evaluation of impacts of energy conservation actions, and presentation of the results. Each one of these topics was discussed.

Source record↗
NASA NTRS1975

A review and preliminary evaluation of methodological factors in performance assessments of time-varying aircraft noise effects

The effects of aircraft noise on human performance is considered. Progress is reported in the following areas: (1) review of the literature to identify the methodological and stimulus parameters involved in the study of noise effects on human performance; (2) development of a theoretical framework to provide working hypotheses as to the effects of noise on complex human performance; and (3) data collection on the first of several experimental investigations designed to provide tests of the hypotheses.

Coates, G. D.↗
NASA NTRS1976

Development of a methodology for classifying software errors

A mathematical formalization of the intuition behind classification of software errors is devised and then extended to a classification discipline: Every classification scheme should have an easily discernible mathematical structure and certain properties of the scheme should be decidable (although whether or not these properties hold is relative to the intended use of the scheme). Classification of errors then becomes an iterative process of generalization from actual errors to terms defining the errors together with adjustment of definitions according to the classification discipline. Alternatively, whenever possible, small scale models may be built to give more substance to the definitions. The classification discipline and the difficulties of definition are illustrated by examples of classification schemes from the literature and a new study of observed errors in published papers of programming methodologies.

Gerhart, S. L.↗
NASA NTRS1976

Software production methodology tested project

The history and results of a 3 1/2-year study in software development methodology are reported. The findings of this study have become the basis for DSN software development guidelines and standard practices. The article discusses accomplishments, discoveries, problems, recommendations and future directions.

Tausworthe, R. C.↗
NASA NTRS1976

The cost of energy from utility-owned solar electric systems. A required revenue methodology for ERDA/EPRI evaluations

This methodology calculates the electric energy busbar cost from a utility-owned solar electric system. This approach is applicable to both publicly- and privately-owned utilities. Busbar cost represents the minimum price per unit of energy consistent with producing system-resultant revenues equal to the sum of system-resultant costs. This equality is expressed in present value terms, where the discount rate used reflects the rate of return required on invested capital. Major input variables describe the output capabilities and capital cost of the energy system, the cash flows required for system operation amd maintenance, and the financial structure and tax environment of the utility.

Source record↗
NASA NTRS1976

A methodology for producing reliable software, volume 1

An investigation into the areas having an impact on producing reliable software including automated verification tools, software modeling, testing techniques, structured programming, and management techniques is presented. This final report contains the results of this investigation, analysis of each technique, and the definition of a methodology for producing reliable software.

Stucki, L. G.↗
NASA NTRS1976

A methodology for small scale rural land use mapping in semi-arid developing countries using orbital imagery. Part 3: Review of land use surveys using orbital imagery in the USA

The author has identified the following significant results. Techniques of preprocessing, interpretation, classification, and ground truth sampling were studied. It has shown the need for a low cost, low level technology, viable, operational methodology to replace the emphasis given in the U.S. to machine processing, which many developing countries cannot afford, understand, nor implement.

Vangenderen, J. L.↗
NASA NTRS1976

A methodology for small scale rural land use mapping in semi-arid developing countries using orbital imagery. Part 6: A low-cost method for land use mapping using simple visual techniques of interpretation

The author has identified the following significant results. It was found that color composite transparencies and monocular magnification provided the best base for land use interpretation. New methods for determining optimum sample sizes and analyzing interpretation accuracy levels were developed. All stages of the methodology were assessed, in the operational sense, during the production of a 1:250,000 rural land use map of Murcia Province, Southeast Spain.

Vangenderen, J. L.↗
NASA NTRS1976

Apparatus and methodology for fire gas characterization by means of animal exposure

While there is a great deal of information available from small-scale laboratory experiments and for relatively simple mixtures of gases, considerable uncertainty exists regarding appropriate bioassay techniques for the complex mixture of gases generated in full-scale fires. Apparatus and methodology have been developed based on current state of the art for determining the effects of fire gases in the critical first 10 minutes of a full-scale fire on laboratory animals. This information is presented for its potential value and use while further improvements are being made.

Marcussen, W. H.↗
NASA NTRS1977

Methodology for back-contamination risk assessment for a Mars sample return mission

The risk of back-contamination from Mars Surface Sample Return (MSSR) missions is assessed. The methodology is designed to provide an assessment of the probability that a given mission design and strategy will result in accidental release of Martian organisms acquired as a result of MSSR. This is accomplished through the construction of risk models describing the mission risk elements and their impact on back-contamination probability. A conceptual framework is presented for using the risk model to evaluate mission design decisions that require a trade-off between science and planetary protection considerations.

Merkhofer, M. W.↗
NASA NTRS1977

Evaluation of analytical methodology for hydrocarbons in high pressure air and nitrogen systems

Information regarding the safety limits of hydrocarbons in liquid and gaseous oxygen, the steps taken for hydrocarbon removal from liquified gases, and the analysis of the contaminants was searched and the results are presented. The safety of hydrocarbons in gaseous systems was studied, and the latest hydrocarbon test equipment and methodology is reviewed. A detailed sampling and analysis plan is proposed to evaluate high pressure GN2 and LOX systems.

Source record↗
NASA NTRS1977

Finite-element methodology for thermal analysis of convectively cooled structures

A finite-element method for steady-state thermal analysis of convectively cooled structures is presented. The method is based on representing the coolant passages by finite elements with fluid bulk temperature nodes and fluid/structure interface modes. Four finite elements are described: two basic elements (mass transport and surface convection) and two integrated elements for applications to discrete tube and plate-fin convectively cooled structural configurations. Comparative finite-element and lumped-parameter thermal analyses of several convectively cooled structures demonstrate the practicality of utilizing finite-element methodology for thermal analysis of realistic convectively cooled structures.

Source record↗
NASA NTRS1978

Candidate substances for space bioprocessing methodology and data specification for benefit evaluation

Analytical and quantitative economic techniques are applied to the evaluation of the economic benefits of a wide range of substances for space bioprocessing. On the basis of expected clinical applications, as well as the size of the patient that could be affected by the clinical applications, eight substances are recommended for further benefit evaluation. Results show that a transitional probability methodology can be used to model at least one clinical application for each of these substances. In each recommended case, the disease and its therapy are sufficiently well understood and documented, and the statistical data is available to operate the model and produce estimates of the impact of new therapy systems on the cost of treatment, morbidity, and mortality. Utilizing the morbidity and mortality information produced by the model, a standard economic technique called the Value of Human Capital is used to estimate the social welfare benefits that could be attributable to the new therapy systems.

Source record↗
NASA NTRS1978

A study of characteristics of intercity transportation systems. Phase 1: Definition of transportation comparison methodology

Decision making in early transportation planning must be responsive to complex value systems representing various policies and objectives. The assessment of alternative transportation concepts during the early initial phases of the system life cycle, when supportive research and technology development activities are defined, requires estimates of transportation, environmental, and socio-economic impacts throughout the system life cycle, which is a period of some 40 or 50 years. A unified methodological framework for comparing intercity passenger and freight transportation systems is described and is extended to include the comparison of long term transportation trends arising from implementation of the various R & D programs. The attributes of existing and future transportation systems are reviewed in order to establish measures for comparison, define value functions, and attribute weightings needed for comparing alternative policy actions for furthering transportation goals. Comparison criteria definitions and an illustrative example are included.

English, J. M.↗