Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “standardization”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,747 records · Page 97
All sourcesNASA NTRSDOE OSTI
NASA NTRS1983

Comparison of low-altitude wind-shear statistics derived from measured and proposed standard wind profiles

Wind shear statistics were calculated for a simulated set of wind profiles based on a proposed standard wind field data base. Wind shears were grouped in altitude in altitude bands of 100 ft between 100 and 1400 ft and in wind shear increments of 0.025 knot/ft. Frequency distributions, means, and standard deviations for each altitude band were derived for the total sample were derived for both sets. It was found that frequency distributions in each altitude band for the simulated data set were more dispersed below 800 ft and less dispersed above 900 ft than those for the measured data set. Total sample frequency of occurrence for the two data sets was about equal for wind shear values between +0.075 knot/ft, but the simulated data set had significantly larger values for all wind shears outside these boundaries. It is shown that normal distribution in both data sets neither data set was normally distributed; similar results are observed from the cumulative frequency distributions.

Usry, J. W.↗
NASA NTRS1983

Standard research materials: Feces and urine

Preparation of the standard research materials, preparation of the samples for analysis, elemental analysis, composition of standard research materials, and methodology are discussed.

Source record↗
NASA NTRS1984

Development of standardized specifications for screening space level integrated circuits and semiconductors

Standardized methods are established for screening of JAN B microcircuits and JANTXV semiconductor components for space mission or other critical applications when JAN S devices are not available. General specifications are provided which outline the DPA (destructive physical analysis), environmental, electrical, and data requirements for screening of various component technologies. This standard was developed for Air Force Space Division, and is available for use by other DOD agencies, NASA, and space systems contractors for establishing common screening methods for electronic components.

Source record↗
NASA NTRS1983

Interface standardization

Central-station applications create a large and attractive market for photovoltaics in the near future. However, some significant barriers lie between the industry of today and realization of that market. Manufacturing capacity and price are two principal impediments. The Utilities, which are the future system owners, are gaining experience with central-station PV power through the Sacramento Municipal Utility District, Hesperia and similar small central-station installations. SMUD has recognized that competition must be maintained to help reduce prices. So little standardization exists that the cost is driven upward to redefine mechanical and electrical interfaces for each vendor. New structues are required for each vendor and nonoptimum field geometries result from attempts to include more than one vendor in an array field. Standards at some hardware level are required.

Spencer, R.↗
NASA NTRS1984

Low altitude wind shear statistics derived from measured and FAA proposed standard wind profiles

Wind shear statistics were calculated for a simulated data set using wind profiles proposed as a standard and compared to statistics derived from measured wind profile data. Wind shear values were grouped in altitude bands of 100 ft between 100 and 1400 ft, and in wind shear increments of 0.025 kt/ft between + or - 0.600 kt/ft for the simulated data set and between + or - 0.200 kt/ft for the measured set. No values existed outside the + or - 0.200 kt/ft boundaries for the measured data. Frequency distributions, means, and standard deviations were derived for each altitude band for both data sets, and compared. Also, frequency distributions were derived for the total sample for both data sets and compared. Frequency of occurrence of a given wind shear was about the same for both data sets for wind shears, but less than + or 0.10 kt/ft, but the simulated data set had larger values outside these boundaries. Neglecting the vertical wind component did not significantly affect the statistics for these data sets. The frequency of occurrence of wind shears for the flight measured data was essentially the same for each altitude band and the total sample, but the simulated data distributions were different for each altitude band. The larger wind shears for the flight measured data were found to have short durations.

Dunham, R. E., Jr.↗
NASA NTRS1983

Standard ozone profiles from balloon and satellite data sets

Standard profiles based on upper level averaged profiles from BUV and lower level averaged profiles from balloon measurements are presented in a parametric representation as a function of time of year and latitude. The representation is a simple 4-parameter function representing the ozone amount (m-atm-cm) in each of 12 atmospheric layers defined following the standard Umkehr convention. The same parameterization is applied to the Nimbus-7 SBUV data and is compared to the BUV/balloon parameterization. The ozone variance unaccounted for by the representation is presented and discussed. The season-latitude representation reduces considerably the ozone variance at all levels and explains much of the correlation between layers. This simple representation and corresponding covariance matrix have been used as a priori information in the ozone vertical profile inversion of the Nimbus-7 SBUV experimental measurements.

Klenk, K. F.↗
NASA NTRS1984

Photometric standard stars for L' and M filter bands

L' (3.8 microns) and M (4.9 microns) photometry of 20 primary and 21 secondary standard stars that are sufficiently faint for large telescope observation is presented. The estimated uncertainties in the magnitudes of the primary standards are 0.01 at L', 0.02 at M, and 0.015 for the L'-M color. A color transformation between the present L' magnitudes and the L magnitudes of Elias et al. (1982) is obtained and found to be near agreement with that predicted for black-bodies.

Sinton, W. M.↗
NASA NTRS1985

NASA/aircraft industry standard specification for graphite fiber toughened thermoset resin composite material

A standard specification for a selected class of graphite fiber/toughened thermoset resin matrix material was developed through joint NASA/Aircraft Industry effort. This specification was compiled to provide uniform requirements and tests for qualifying prepreg systems and for acceptance of prepreg batches. The specification applies specifically to a class of composite prepreg consisting of unidirectional graphite fibers impregnated with a toughened thermoset resin that produce laminates with service temperatures from -65 F to 200 F when cured at temperatures below or equal to 350 F. The specified prepreg has a fiber areal weight of 145 g sq m. The specified tests are limited to those required to set minimum standards for the uncured prepreg and cured laminates, and are not intended to provide design allowable properties.

Source record↗
NASA NTRS1984

Prospects for atomic frequency standards

The potentialities of different atomic frequency standards which are not yet into field operation, for most of them, but for which preliminary data, obtained in laboratory experiments, give confidence that they may improve greatly the present state of the art are described. The review will mainly cover the following devices: (1) cesium beam frequency standards with optical pumping and detection; (2) optically pumped rubidium cells; (3) magnesium beam; (4) cold hydrogen masers; and (5) traps with stored and cooled ions.

Audoin, C.↗
NASA NTRS1985

A suggested standardized format for cosmic ray ground-level event data

A standardized format is suggested for the archival storage and exchange of neutron monitor data obtained during solar flare initiated ground level cosmic ray events. Using the data for the 7 May 1978 ground level event, a format has been developed that incorporates hourly data preceding and following the event and small time interval data immediately before and during the event. Provision has been made for the inclusion of uncorrected and corrected data as well as the atmospheric pressure. The cosmic ray intensity data are then reduced to a standard counting rate of counts per second facilitating the graphing and comparison of these data for various analyses.

Shea, M. A.↗
NASA NTRS1985

The Use of a Laser Doppler Velocimeter in a Standard Flammability Tube

The use of the Laser Doppler Velocimeter, (LDV), to measure the flow associated with the passage of a flame through a standard flammability limit tube (SFLT) was studied. Four major results are presented: (1) it is shown that by using standard ray tracing calculations, the displacement of the LDV volume and the fringe rotation within the experimental error of measurement can be predicted; (2) the flow velocity vector field associated with passage of an upward propagating flame in an SFLT is determined; (3) it is determined that the use of a light interruption technique to track particles is not feasible; and (4) it is shown that a 25 mW laser is adequate for LDV measurements in the Shuttle or Spacelab.

Strehlow, R. A.↗
NASA NTRS1986

Vacuum-Ultraviolet Intensity-Calibration Standard

Portable light source enables calibration of spectrometers. Vacuum Ultraviolet Light (40 to 200 nm) produced in electron-impact emission chamber by leading beam of gas across electron beam. Photons observed at right angles to electron-beam axis. Previously, there were blackbody standards in visible and near ultraviolet, but no intensity-calibration standards in VUV.

Ajello, J. M.↗
NASA NTRS1985

Space Station crew interface specifications and standards

NASA's Space Station Human Productivity and Man/System Integration Standards programs are described. The data collection methodologies and analyses utilized in the productivity study are examined. The study reveals that attention to habitability is required in order to maximize human productivity for on-orbit operations. The nine program tasks used to develop standards for man/system integration are discussed.

Geer, C. W.↗
NASA NTRS1985

A dynamic pressure calibration standard

A dynamic pressure calibration standard has been developed for calibrating flush diaphragm mounted pressure transducers. Pressures up to 20 kPa (3 psi) have been accurately generated over a frequency range of 50 to 1800 hz. The uncertainty of the standard is +/-5 pct to 5kPa (.75 psi) and +/-10 pct from 5 kPa (.75 psi) to 20 kPa (3 psi). The system consists of two conically shaped, aluminum columns, one 5 cm (2 in.) high for low pressures and another 11 cm (4.3 in.) high for higher pressures, each filled with a viscous fluid. A column is mounted on the armature of a vibration exciter which imparts a sinusoidally varying acceleration to the fluid column. Two pressure transducers mounted at the base of the column sense the sinusoidally varying pressure. This pressure is determined from measurements of the density of the fluid, the height of the fluid, and the acceleration of the column. A section of the taller column is filled with steel balls to control the damping of the fluid to extend its useful frequency range.

Schutte, P. C.↗
NASA NTRS1986

A proposal for adopting a standard coordinate system for defining atmospheric nomenclature for the giant planets

Although the albedo of specific belts and zones varies as a function of time, there is evidence that wind maxima may be fixed in latitude. Before considering a standard notation for wind jets, it is necessary to establish a coordinate system within which the nomenclature would be defined. Traditionally, the BAA has used planetographic latitudes; however, this system is based not only on an accurate determination of the polar diameter but also on the assumption that the equipotential surfaces can be represented by biaxial ellipsoids. The International Astronomical Union strives to adopt unambiguous nomenclature that will be universally acceptable. It is proposed that planetocentric coordinates be utilized and that a standardized value of the ratio of the polar diameter to the equatorial diameter be established for each planet to facilitate transformation into planetographic coordinates.

Beebe, R.↗
NASA NTRS1987

Preliminary report on candidates for AGARD standard aeroelastic configurations for dynamic response

At the request of the Aeroelasticity Subcommittee of the AGARD Structures and Materials Panel, a survey of member countries has been conducted to seek candidates for a prospective set of standard configurations to be used for comparison of calculated and measured dynamic aeroelastic behavior with emphasis on the transonic speed range. This set is a sequel to that established several years ago for comparisons of calculated and measured aerodynamic pressures and forces. Approximately two dozen people in the United States, and more than three dozen people in the other member countries, were contacted. This preliminary report presents the results of the survey and an analysis of those results along with recommendations for the initial set of standard configurations and for additional experimental work needed to fill significant gaps in the available information.

Yates, E. Carson, Jr.↗
NASA NTRS1986

Space Shuttle standard launch window

To maximize the efficiency of the Space Transportation System as a shared cargo launch system and to enhance the mixability and launch opportunities for payloads carried on the Space Shuttle, the National Aeronautics and Space Administration has developed a shared cargo standard launch window. The launch window is based on the transfer orbit sun angle requirements of an established, common class of geosynchronous communications satellites. This standard window is applicable to mixed cargoes launched from the John F. Kennedy Space Center into 28.5 deg inclination orbits. The window consists of two time periods, each 2 hrs long and centered at 0023 and 1223 Greenwich mean time; it extends unchanged throughout the year.

Deatkine, David D.↗