Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “usability”

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 793 records · Page 44
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Use of data from space for earth resources exploration and management in Alabama

The University of Alabama, the Geological Survey of Alabama, and the George C. Marshall Space Flight Center are involved in an interagency, interdisciplinary effort to use remotely sensed, multispectral observations to yield improved and timely assessment of earth resources and environmental quality in Alabama. It is the goal of this effort to interpret these data and provide them in a format which is meaningful to and readily usable by agencies, industries, and individuals who are potential users throughout the State.

Lamoreaux, P. E.↗
NASA NTRS1973

Predict ephemeral and perennial range quantity and quality during normal grazing season

There are no author-identified significant results in this report. Analysis of imagery made during the second and third 2-month periods has yielded little usable information for the following reasons. Imagery taken of the deserts in Arizona and California and semi-arid southeastern Oregon has been of poor quality. Because of high reflectance of light from barren desert soils, imagery is over-exposed and positive transparencies are washed out. Imagery was also taken when plants were dormant so that differences in vegetation growth and development as exhibited by changes in tone of color infrared are nonexistent.

Bentley, G.↗
NASA NTRS1972

A 928 sq m (10000 sq ft) solar array

As the power requirements for space vehicles increases, the area of solar arrays that convert solar energy to usable electrical power increases. The requirements for a 928 sq m (10,000 sq ft) array, its design, and a full-scale demonstration of one quadrant (232 sq m (2500 sq ft)) deployed in a one-g field are described.

Lindberg, D. E.↗
NASA NTRS1972

Cathodochromic cathode ray tube: An operations manual

A cathodochromic (CC) storage and display system capable of storing full TV resolution images has been built. The images are derived from standard TV signals: composite video, composite sync, composite blanking, horizontal drive, and vertical drive. Image storage takes place in the CC CRT; the fixed image is written for several TV frames for the contrast to be usable. Once stored on the CC CRT, the image can be read out in one of three modes: with the eye, a 35-mm camera, or a TV camera. Incoming information may also be stored in a storage tube similar to the CC CRT but with a phosphor layer behind the CC layer. By exciting the phosphor layer with a standard raster scan it is possible to read out an image stored in the CC layer in one of three modes: direct viewing, photography, or flying-spot readout using a photomultiplier.

Heyman, P. M.↗
NASA NTRS1972

NERVA mass properties computer methodology

The computer codes are presented that were used for the weight, center of gravity, and mass moment of inertia calculations and documentation for the NERVA. The two programs, E15301 and 12001B, are the basic tools used for weights work on the NERVA program. Used in conjunction with one another, they allow for rapid weights estimates for new concepts or changes while allowing for orderly documentation, which is a necessity in any effective weights effort. Program E15301 requires that each component be resolved into a collection of standard shapes. Separate subroutines then process geometric and material density data for each entry. The master program the performs all calculations necessary to combine these results into a total weight, center of gravity, and moment of inertia for the component. Program 12001B accepts previously calculated weight and center of gravity data for individual components. The program sums weights and calculates center of gravities and moments of inertia for systems of up to four levels of assemblies. The output identifies the engine parts in a format usable directly in a formal report.

Hall, I. K.↗
NASA NTRS1973

Research on oxygen recovery systems for use in space capsules

An improved electrochemical process was investigated for the recovery of oxygen from the atmospheres of manned space capsules. The objective of the proposed system is to recover the oxygen from CO2 with high efficiency and to recover the additional amount of oxygen from water that is required to provide a total oxygen makeup stream of about 2.0 lb/man-day. The carbon from the CO2 must be converted into a readily disposable or usable form. The results are given of initial experiments with a porous stainless steel cathode in a LiCl-KCl electrolyte with small additions of oxide, carbonate, and hydroxide.

Selman, J. R.↗
NASA NTRS1973

Automated attendance accounting system

An automated accounting system useful for applying data to a computer from any or all of a multiplicity of data terminals is disclosed. The system essentially includes a preselected number of data terminals which are each adapted to convert data words of decimal form to another form, i.e., binary, usable with the computer. Each data terminal may take the form of a keyboard unit having a number of depressable buttons or switches corresponding to selected data digits and/or function digits. A bank of data buffers, one of which is associated with each data terminal, is provided as a temporary storage. Data from the terminals is applied to the data buffers on a digit by digit basis for transfer via a multiplexer to the computer.

Chapman, C. P.↗
NASA NTRS1973

Ice development on Lake Champlain

The author has identified the following significant results. Only one usable ERTS-1 scene was available for lake ice survey of Lake Champlain. The January 8, 1973, coverage (image no. 1169-11521) revealed the presence of various ice tones, patterns, and arrangements as well as open water. MSS band 5 imagery provided the most useful data. While it was not possible to differentiate open water from one - two day old ice, which only occurred over a small portion of the lake area, it was possible to interpret the tonal signatures of the frozen portion in terms of freezing history or age. The dark gray-tones of new, smooth ice contrasts with the medium gray-tones of older ice, and the rough texture of wind-jammed bay ice. Mapping of these patterns seems quite feasible with moderate enlargement of the scene (2 to 3X).

Lind, A. O.↗
NASA NTRS1973

Evaluation of ERTS-1 imagery in mapping and managing soil and range resources in the Sand Hills Region of Nebraska

The author has identified the following significant results. Collection of ground truth data provided ground cover percent and the components of ground cover makeup. Percent bare soil appears to have greatest influence on imagery density of sites studied. Forage density estimates can be made on band 5 of MSS, provided site category identification is known. Additional data are provided concerning forage density and vegetation-soil relationship by color composites of MSS imagery. Reflectance differences shown on MSS bands 6 and 7 by Sand Hills lakes are related to water quality and possibly more specifically to total dissolved ions present in the water. Winter imagery with snow cover and low sun angle shows a marked enhancement of topography are associated with differences in forage density. High altitude color infrared photography appears to be a usable tool for recognition, measurement, and evaluation of go-back land.

Seevers, P. M.↗
NASA NTRS1973

A simplified ductile-brittle transition temperature tester

The construction and operation of a versatile, simplified bend tester is described. The tester is usable at temperatures from - 192 to 650 C in air. Features of the tester include a single test chamber for cryogenic or elevated temperatures, specimen alining support rollers, and either manual or motorized operation.

Arias, A.↗
NASA NTRS1973

Geosynchronous platform definition study. Volume 3: Geosynchronous mission characteristics

The objectives of the study were to examine the nature of currently planned and new evolutionary geosynchronous programs, to analyze alternative ways of conducting missions, to establish concepts for new systems to support geosynchronous programs in an effective and economical manner, and to define the logistic support to carry out these programs. In order to meet these objectives, it was necessary to define and examine general geosynchronous mission characteristics and the potentially applicable electromagnetic spectrum characteristics. An organized compilation of these data is given with emphasis on the development and use of the data. Fundamental geosynchronous orbit time histories, mission profile characteristics, and delivery system characteristics are presented. In addition, electromagnetic spectrum utilization is discussed in terms of the usable frequency spectrum, the spectrum potentially available considering established frequency allocations, and the technology status as it affects the ability to operate within specific frequency bands.

Source record↗
NASA NTRS1973

The role of man in flight experiment payload missions. Volume 1: Results

It is pointed out that a controversy exists concerning the required role of man, and his attendant skills and levels of skills, for Sortie Lab operations. As a result, a study was conducted to generate a taxonomy of candidate crew roles which would: (1) be applicable across all experiments, and (2) be usable for Sortie scientists and engineers in determination of level of skill as well as type of skill. Nine basic roles were identified in the study, and the tasks associated with each were developed from a functional description of a generalized in-flight experiment. The functional analysis comprised the baseline for establishment of crew roles, with roles being defined as combinations of tasks, associated skills, and knowledges. A role classification scheme was developed in which the functions and tasks identified were allocated to each of the nine role types. This classification scheme is presented together with the significant results of the study.

Malone, T. B.↗
NASA NTRS1972

Pseudorandom noise for telemetry error rate measurement applications and limitations.

A pseudorandom noise (PRN) generator functional design has been developed which is superior to the commercially available instrument in usable bandwidth and in the closeness of fit to the gaussian probability distribution in the 'tails' of the curve. The principal disadvantage of PRN sources for bit error rate (BER) measurements is that the probability distribution is truncated in the tails. This truncation of the probability distribution results in a similar truncation of the BER curve - i.e., there is a minimum BER which can be measured, below which the only possible result is zero. The minimum nonzero BER actually computed with the PRN source developed was 0.00001 with a pseudorandom sequence of 131,071 bits. It is theoretically possible, with a longer sequence, to achieve a minimum BER of 0.000001 with the same design.

Hopkins, P. M.↗
NASA NTRS1973

Photography of a lithium vapor trail during the daytime.

Barium and lithium vapors were released from sounding rockets in the thermosphere and observed from aboard a jet aircraft at an altitude of 40,000 ft. The purpose of the releases was to demonstrate the feasibility of an all-weather technique for observing chemical releases and to evaluate methods of observing daytime releases. The selected flight plan of the aircraft allowed a series of observations of the trail from two different straight line paths. Data were recorded photographically. The reduction in sky brightness at the 40,000-ft altitude as compared to the ground allows the use of a filter with a 10-A bandwidth for trail photography in the daytime. These photographs verified the calculation of the usable angular field of the narrow-band filters. Photographs of a 45-min-old trail of lithium vapor were obtained up to 20 min after sunrise at the aircraft. It is concluded that now vapor trail observations may be made during the daytime without regard to weather and logistic restrictions.

Bedinger, J. F.↗
NASA NTRS1973

Experimental landings in a spoiler-equipped light aircraft.

This report presents the results of a flight test program to determine the effects on landings of wide variations in approach path angle and approach airspeed for different kinds of piloting technique. Over 400 landings were made at approach speeds from 60 to 120 mph and approach path angles from 3 to 18 deg. Several variations of pilot technique involving different operations of the throttle/spoiler control were investigated. It is shown that very large ranges of airspeed and approach path angle can be accommodated with rather moderate penalties in landing distance and difficulty. With the spoiler-equipped aircraft, the best approach speeds are considerably higher than would be usable without spoilers, and approach path angles can be used which are far beyond those normally possible without spoilers.

Seckel, E.↗
NASA NTRS1973

Algebraic decoding of block codes over a q-ary input, Q-ary output channel, Q greater than q.

Decoding algorithms designed for one output alphabet are shown to be effectively usable for channels with a different output alphabet. The described technique that makes this possible can be used in conjunction with an arbitrary distance measure between input and output vectors. Thus, Hamming distance, Lee distance, or a burst distance can be assumed. Examples are presented for each of these distances.

Wainberg, S.↗
NASA NTRS1973

Hydrogen evolution in nickel-water heat pipes.

A study was made of the evolution of hydrogen gas in nickel-water heat pipes for the purpose of investigating methods of accelerated life testing. The data were analyzed in terms of a phenomenological corrosion model of heat pipe degradation which incorporates corrosion and oxidation theory and contains parameters which can be determined by experiment. The gas was evolved with a linear time dependence and an exponential temperature dependence with an activation energy of 1.03 x 10 to the minus 19th joules. A flow-rate dependence of the gas evolution was found in the form of a threshold. The results were used to predict usable lifetimes of heat pipes operated at normal operating conditions from results taken under accelerated operating conditions.

Anderson, W. T.↗