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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 343 records · Page 19
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Detection of turbidity dynamics in Tampa Bay, Florida using multispectral imagery from ERTS-1

In 1970, Congress authorized the deepening of the Tampa Bay channel (Rivers and Harbors Act of 1970) from 34 to 44 feet. In order to determine the effects of this deepening on circulation, water quality, and biota, during and after the construction, the U.S. Geological Survey, in cooperation with the Tampa Port Authority, has collected data and developed a digital simulation model of the bay. In addition to data collected using conventional tools, use is being made of data collected from ERTS-1. Return beam vidicon (RBV) multispectral data were collected, while a shell dredging barge was operating in the bay, and used for turbidity recognition and unique spectral signatures representative of type and amount of material in suspension. A three-dimensional concept of the dynamics of the plume was achieved by superimposing the parts of the plume recognized in each RBV band. This provides a background for automatic computer processing of ERTS data and three-dimensional modeling of turbidity plumes.

Coker, A. E.↗
NASA NTRS1973

Rate of convergence of a class of methods of feasible directions.

This paper deals with the rate of convergence of four methods of feasible directions: the Zoutendijk procedures 1 and 2 and two modifications of these procedures due to the authors. It is shown that of these methods, the two due to the authors converge linearly under convexity assumptions, that the Zoutendijk procedure 2 converges sublinearly under these assumptions, and that the Zoutendijk procedure 1 converges linearly provided the solution of the problem is a vertex of the constraint set.

Pironneau, O.↗
NASA NTRS1973

Elastic wave velocities in anorthosite and anorthositic gabbros from Apollo 15 and 16 landing sites

Laboratory measurements of ultrasonic velocities in lunar samples 15065, 15555, 15415, 60015, and 61016 as well as in synthetic materials corresponding to compositions of anorthositic gabbros are presented as a function of hydrostatic pressure to about 7 kb. The author examined the seismic velocity distributions in the moon with reference to the variations to be expected in a homogeneous medium. The lunar mantle begins about 60 km, and the velocity of P waves in this area is about 7.7 km/sec. Variation of the seismic parameter with depth in the upper crust (about 20 km thick) is much too rapid to be explained by compression of a uniform material and the departure from expectation is so great that no reasonable adjustment of the material parameters can bring agreement; therefore, this author concludes that this result in this region of the moon is not due to self-compression but to textural gradients. In the lower crust (about 40 km thick), the region is shown to be relatively homogeneous, consisting probably of anorthositic rocks.

Chung, D. H.↗
NASA NTRS1974

Spectrometric properties of crystals for X-ray astronomy. I

Preliminary results are reported on measurements of X-ray reflection coefficients, rocking-curve width estimates, and factors that influence these for KAP, EDDT, and ADP crystals. The agreement between parameters measured in the authors' laboratory and others over a period of some ten years, and the uniformity among the authors' samples, indicate that KAP as commercially supplied is amenable to a single theoretical description. This permits application of X-ray diffraction theory, which outlined and compared to measurements with good agreement.

Burek, A. J.↗
NASA NTRS1975

Detailed requirements document for the Interactive Financial Management System (IFMS), volume 1

The detailed requirements for phase 1 (online fund control, subauthorization accounting, and accounts receivable functional capabilities) of the Interactive Financial Management System (IFMS) are described. This includes information on the following: systems requirements, performance requirements, test requirements, and production implementation. Most of the work is centered on systems requirements, and includes discussions on the following processes: resources authority, allotment, primary work authorization, reimbursable order acceptance, purchase request, obligation, cost accrual, cost distribution, disbursement, subauthorization performance, travel, accounts receivable, payroll, property, edit table maintenance, end-of-year, backup input. Other subjects covered include: external systems interfaces, general inquiries, general report requirements, communication requirements, and miscellaneous. Subjects covered under performance requirements include: response time, processing volumes, system reliability, and accuracy. Under test requirements come test data sources, general test approach, and acceptance criteria. Under production implementation come data base establishment, operational stages, and operational requirements.

Dodson, D. B.↗
NASA NTRS1975

Strong scintillations in astrophysics. I - The Markov approximation, its validity and application to angular broadening

The Markov approximation to the propagation of waves in an extended, irregular medium is discussed in an astrophysical context. A new derivation is presented which is simple and which shows that the assumption of Gaussian statistics used by previous authors is irrelevant. We discuss the relevance of the approximation and show that it may apply in many situations of interest, including interstellar scintillations of pulsar signals. The approximation does not require the assumption of weak scattering or Gaussian correlation functions. The Markov equation for the angular spectrum is particularly simple, and solutions are discussed for typical turbulence spectra. It is found that the equation for the angular spectrum is very nearly that used by previous authors, and the present discussion shows that these results are much more general than previously thought. A possible observational test for distinguishing between Gaussian and power-law interstellar density spectra is discussed.

Lee, L. C.↗
NASA NTRS1977

Liquefied natural gas (LNG) safety

Bibliography, assembled from computer search of NASA Aerospace Safety Data Bank, including title of report, author, abstract, source, description of figures, key references, and key words or subject terms. Publication is indexed by key subjects and by authors. Items are relevant to design engineers and safety specialists.

Ordin, P. M.↗
NASA NTRS1976

Bibliography on Liquefied Natural Gas (LNG) safety

Approximately 600 citations concerning safety of liquefied natural gas and liquid methane are presented. Each entry includes the title, author, abstract, source, description of figures, key references, and major descriptors for retrieving the document. An author index is provided as well as an index of descriptors.

Ordin, P. M.↗
NASA NTRS1976

Summary of development and recommendations for a quality assurance program for the procurement and manufacture of urban mass transit operating equipment and systems

A viable quality program for the urban mass transit industry, and a management approach to ensure compliance with the program are outlined. Included are: (1) a set of guidelines for quality assurance to be imposed on transit authorities, and a management approach to ensure compliance with them; (2) a management approach to be used by the transit authorities (properties) for assuring compliance with the QA guidelines; and (3) quality assurance guidelines to be imposed by properties and umta for procurement of hardware and systems.

Witkin, S. A.↗
NASA NTRS1977

Comparative analysis of the designs and implementation of vehicles based on reactive propulsion proposed during the nineteenth and beginning of the twentieth centuries

Examination of the presently known historical scientific literature related to the problem of reactive flight indicates that considerable attention had already been given to the idea of reactive propulsion in the nineteenth century; about thirty designs for reaction flying vehicles were proposed during this period. However, the authors of a majority of the designs limited themselves only to a presentation of a diagram of the engine or an account of the principle of its operation, giving neither plans for its structural development nor precise calculations of the amount of energy required for accomplishing reaction flight. None of these authors considered the reaction flying vehicle as an object of variable mass, their choice of energy sources was extremely random, and the theory of the flight of reaction flying vehicles remained completely undeveloped. Early rocket designs of Nezhdanovsky, Ganswindt, Goddard, Tsiolkovsky, and others are examined and the evolution of liquid-propellant rocket engines, solid-propellant rocket engines, and jet aircraft engines is reviewed.

Sokolskiy, V. N.↗
NASA NTRS1976

Creative revision - From rough draft to published paper

The process of revising a technical or scientific paper can be performed more efficiently by the people involved (author, co-author, supervisor, editor) when the revision is controlled by breaking it into a series of steps. The revision process recommended here is based on the levels-of-edit concept that resulted from a study of the technical editorial function at the Jet Propulsion Laboratory of the California Institute of Technology. Types of revision discussed are Substantive, Policy, Language, Mechanical Style, Format, Integrity, and Copy Clarification.

Buehler, M. F.↗
NASA NTRS1978

Legal issues inherent in Space Shuttle operations

The National Aeronautics and Space Act of 1958 (NASAct) is discussed with reference to its relevance to the operation of the Space Shuttle. The law is interpreted as giving NASA authority to regulate specific Shuttle missions, as well as authority to decide how much space aboard the Shuttle gets rented to whom. The Shuttle will not, however, be considered a 'common carrier' either in terms of NASAct or FAA regulations, because it will not be held available to the public-at-large, as are the flag carriers of various national airlines, e.g., Lufthansa, Air France, Aeroflot, etc. It is noted that the Launch Policy of 1972, which ensures satellite launch assistance to other countries or international organizations, shall not be interpreted as conferring common carrier status on the Space Shuttle.

Mossinghoff, G. J.↗
NASA NTRS1979

Ames Research Center publications, 1977

This bibliography lists 786 formal NASA publications, journal articles, books, chapters of books, patents, and contractor reports which appeared during 1977 or which were not included in previous annual bibliographies. Citations are arranged by directorate, type of publication, and author. Each NASA report is identified by a technical report and accession number to facilitate ordering. An author index is provided.

Source record↗
NASA NTRS1979

Optical communication with two-photon coherent states. II - Photoemissive detection and structured receiver performance

In a previous paper (1978), the authors developed a method of analyzing the performance of two-photon coherent state (TCS) systems for free-space optical communications. General theorems permitting application of classical point process results to detection and estimation of signals in arbitrary quantum states were derived. The present paper examines the general problem of photoemissive detection statistics. On the basis of the photocounting theory of Kelley and Kleiner (1964) it is shown that for arbitrary pure state illumination, the resulting photocurrent is in general a self-exciting point process. The photocount statistics for first-order coherent fields reduce to those of a special class of Markov birth processes, which the authors term single-mode birth processes. These general results are applied to the structure of TCS radiation, and it is shown that the use of TCS radiation with direct or heterodyne detection results in minimal performance increments over comparable coherent-state systems. However, significant performance advantages are offered by use of TCS radiation with homodyne detection. The abstract quantum descriptions of homodyne and heterodyne detection are derived and a synthesis procedure for obtaining quantum measurements described by arbitrary TCS is given.

Shapiro, J. H.↗
NASA NTRS1978

Some observations on four current subjects related to aeroelastic stability

After introductory comments on the literature and the purposes of this paper, a table is presented summarizing the author's views on some currently solved vs partially unsolved problems related to aeroelastic stability. The term 'solved' is used in the practical sense that engineers are able to cope confidently with that problem during the process of structural design. Selected entries in the table are reviewed, partially to motivate the topics in the rest of the paper. The 'four current subjects' are chosen both for timeliness and because they are among the ongoing interests of the Stanford group. The first involves the prediction of linearized unsteady aerodynamic loads due to arbitrary motions of streamlined shapes. Some contributions by Edwards are refined, which were motivated by the requirements of active control system design. The second subject is nonlinear unsteady aerodynamics for the transonic regime. After describing a few useful developments from locally-linear theory and computational fluid dynamics, there is suggested an empirical procedure for interim-analysis purposes. The third and fourth subjects concern recent discoveries regarding the aeroelastic stability of large-aspect-ratio wings and wind turbines. The former work is mainly that of Petre and Boyd. The latter includes some of the author's own preliminary discoveries about the performance and dynamics of vertical-axis machines.

Ashley, H.↗
NASA NTRS1979

An emission-line survey of the Milky Way

Direct photography of gaseous nebulae using interference filters to isolate individual emission lines is capable both of discriminating between different ions and of enhancing the visibility of nebulae by suppressing stellar images and the quasi-continuous sky background in favor of the chosen band pass. The instrumentation used in an examination of the ionization structure of emission nebulae and of the galactic plane in general, is described, as well as the characteristics of the prints obtained. Reasonable exposure times were obtained with the use of an image intensifier and five interference filters isolated the band passes chosen for the survey. A rough map of each field is presented with a print from the Becvar Skalnate Pleso covering the same area. The structural differences which the authors hoped to record can be seen in many of the fields included in this volume. For purposes of illustration, they are strikingly shown in the fields centered about the following "new" galactic coordinates, where l is longitude and b is latitude: I = 138 °, b = 0°; l = 293 °, b = 0°; and l = 263 °, b = 0 °. In addition to investigating the structure of known emission nebulae, the authors also hoped to find some new objects. By far the most striking of such discoveries is the new supernova remnant in the field l= 65.5 °, b = +5 °.

wide-field camera↗
NASA NTRS1980

Propulsion controls

Increased system requirements and functional integration with the aircraft have placed an increased demand on control system capability and reliability. To provide these at an affordable cost and weight and because of the rapid advances in electronic technology, hydromechanical systems are being phased out in favor of digital electronic systems. The transition is expected to be orderly from electronic trimming of hydromechanical controls to full authority digital electronic control. Future propulsion system controls will be highly reliable full authority digital electronic with selected component and circuit redundancy to provide the required safety and reliability. Redundancy may include a complete backup control of a different technology for single engine applications. The propulsion control will be required to communicate rapidly with the various flight and fire control avionics as part of an integrated control concept.

Harkney, R. D.↗