Magnetic or integrated circuits - A comparative analysis of their application to a micrometeoroid sensor scanning program
Applicability of magnetic or integrated circuits to micrometeoroid sensor scanning
MICROMETEOROID↗
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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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A comparative analysis of two concepts in the generation of uniform pseudo-random numbers.
Pseudorandom number generation within digital computers
Canavos, G. C.↗
Survey and comparative analysis of current geophysical models
Legendre polynomials for gravitational field and orbit perturbation
Von Puttkamer, J.↗
A comparative analysis of the decoupling effects in a magnetic forming beryllium coil assembly
Digital computer for determining currents and forces in magnetic forming beryllium coil assembly
Bennett, L. D.↗
A comparative analysis of the professional's occupational environment at the Manned Spacecraft Center
Nonsupervisory aerospace technologists at Manned Spacecraft Center attitudes toward work environment
Hamilton, R. A.↗
Comparative analysis of acoustic testing techniques, exhibit A Final report
Calculation methods for vibration responses of spacecraft structural members to acoustic fields
Gruner, W. J.↗
Information services for comparative analysis of biorhythm research
References and full text documents are presented in support of continuing research and research planning for the NASA behavioral physiology program. Areas covered include: (1) desynchronosis and performance; (2) effects of alcohol, common colds, drugs, and toxic hazards on performance; (3) effects of stress on rhythm of plasma steroids; (4) data processing of biological rhythms; (5) pharmacology and biological rhythms; (6) mechanisms of biological rhythms; and (7) development of biological rhythms.
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A reliability and comparative analysis of two standby system configurations.
Equations are derived which enable one to calculate the system reliability for parallel or triple modular redundant systems with standby spares. Software error detection is introduced into the TMR/Spares system configuration in order to utilize fully all of the units. An indication of the sensitivity of the system reliability to an increase in the number of spares, partitioning, switching, variations in the powered and unpowered failures rates, and time is presented. A comparison of the parallel and the TMR/Spares system configurations, under similar conditions, is given.
Taylor, D. S.↗
A comparative analysis of area navigation systems in general aviation
Radio navigation systems which offer the capabilities of area navigation to general aviation operators are discussed. The systems considered are: (1) the VORTAC system, (2) the Loran-C system, and (3) the Differential Omega system. The inital analyses are directed toward a comparison of the systems with respect to their compliance to specified performance parameters and to the cost effectiveness of each system in relation to those specifications. Further analyses lead to the development of system cost sensitivity charts, and the employment of these charts allows conclusions to be drawn relative to the cost-effectiveness of the candidate navigation system.
Dodge, S. M.↗
A comparative analysis of remote sensing scale/system attributes for a multi-level land use classification system
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Higgs, G. K.↗
Comparative analysis of errors in different methods of calculating L, B-coordinates
Due to considerable difficulties of calculating L, B-coordinates, several simplified methods are currently used. The relative errors in L, B-coordinates calculated by approximate methods are given. It is suggested that different methods be used to calculate L, B-coordinates in the solution of various problems.
Getselev, I. V.↗
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.↗
Comparative analysis of PA-31-350 Chieftain (N44LV) accident and NASA crash test data
A full scale, controlled crash test to simulate the crash of a Piper PA-31-350 Chieftain airplane is described. Comparisons were performed between the simulated crash and the actual crash in order to assess seat and floor behavior, and to estimate the acceleration levels experienced in the craft at the time of impact. Photographs, acceleration histories, and the tested airplane crash data is used to augment the accident information to better define the crash conditions. Measured impact parameters are presented along with flight path velocity and angle in relation to the impact surface.
Hayduk, R. J.↗
Comparative analysis of various approaches to evaluating the parameters of multidimensional models
The problem of evaluating parameters of a multidimensional model according to measurement results is examined. The conditions on which the problem solution depends are itemized.
Guran, L. S.↗
A comparative analysis of rawinsonde and NIMBUS 6 and TIROS N satellite profile data
Comparisons are made between rawinsonde and satellite profiles in seven areas for a wide range of surface and weather conditions. Variables considered include temperature, dewpoint temperature, thickness, precipitable water, lapse rate of temperature, stability, geopotential height, mixing ratio, wind direction, wind speed, and kinematic parameters, including vorticity and the advection of vorticity and temperature. In addition, comparisons are made in the form of cross sections and synoptic fields for selected variables. Sounding data from the NIMBUS 6 and TIROS N satellites were used. Geostrophic wind computed from smoothed geopotential heights provided large scale flow patterns that agreed well with the rawinsonde wind fields. Surface wind patterns as well as magnitudes computed by use of the log law to extrapolate wind to a height of 10 m agreed with observations. Results of this study demonstrate rather conclusively that satellite profile data can be used to determine characteristics of large scale systems but that small scale features, such as frontal zones, cannot yet be resolved.
Scoggins, J. R.↗
Comparative analysis of techniques for evaluating the effectiveness of aircraft computing systems
Performability analysis is a technique developed for evaluating the effectiveness of fault-tolerant computing systems in multiphase missions. Performability was evaluated for its accuracy, practical usefulness, and relative cost. The evaluation was performed by applying performability and the fault tree method to a set of sample problems ranging from simple to moderately complex. The problems involved as many as five outcomes, two to five mission phases, permanent faults, and some functional dependencies. Transient faults and software errors were not considered. A different analyst was responsible for each technique. Significantly more time and effort were required to learn performability analysis than the fault tree method. Performability is inherently as accurate as fault tree analysis. For the sample problems, fault trees were more practical and less time consuming to apply, while performability required less ingenuity and was more checkable. Performability offers some advantages for evaluating very complex problems.
Hitt, E. F.↗
A comparative analysis of GPS range, Doppler and interferometric observations for geodetic positioning
Geodetic positioning accuracies obtained from range, integrated Doppler and double differenced interferometric phase observations from a constellation of twenty-four Global Positioning System satellites are presented. It is demonstrated the GPS range and Doppler observations will provide sufficient accuracy for the estimation of geodetic coordinates. However the instability of the receiver atomic oscillator will limit the usefulness of these observations in providing rapid first-order baseline determination. Interferometric phase measurements twice differenced to eliminate clock error appear as an alternate procedure for providing such accuracies.
Fell, P. J.↗
Comparative analysis of the conceptual design studies of potential early commercial MHD power plants (CSPEC)
A conceptual design study of the MHD/steam plant that incorporates the use of oxygen enriched air preheated in a metallic heat exchanger as the combustor oxidant showed that this plant is the most attractive for early commercial applications. The variation of performance and cost was investigated as a function of plant size. The contractors' results for the overall efficiencies are in reasonable agreement considering the slight differences in their plant designs. NASA LeRC is reviewing cost and performance results for consistency with those of previous studies, including studies of conventional steam plants. LeRC in house efforts show that there are still many tradeoffs to be considered for these oxygen enriched plants and considerable variations can be made in channel length and level of oxygen enrichment with little change in overall plant efficiency.
Sovie, R. J.↗