53,233 research outputs found

    Phonocardiograph microphone is rugged and moistureproof

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    Microphone used as a phonocardiograph transducer monitors small amplitude audio signals in the presence of large shock loads and high humidity. It contains a lead zirconate-lead titanate piezoelectric plate encapsulated in a flexible polyurethane resin. The resin is contained in a sealed nylon case having a diameter of less than one inch

    Phonocardiograph transducer Patent

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    Piezoelectric transducer for monitoring sound waves of physiological origi

    Fixed-Base Simulator Studies of the Ability of the Human Pilot to Provide Energy Management Along Abort and Deep-Space Entry Trajectories

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    A simulation study has been made to determine a pilot's ability to control a low L/D vehicle to a desired point on the earth with initial conditions ranging from parabolic orbits to abort conditions along the boost phase of a deep-space mission. The program was conducted to develop procedures which would allow the pilot to perform the energy management functions required while avoiding the high deceleration or skipout region and to determine the information display required to aid the pilot in flying these procedures. The abort conditions studied extend from a region of relatively high flight-path angles at suborbital velocities while leaving the atmosphere to a region between orbital and near-escape velocity outside the atmosphere. The conditions studied included guidance from suborbital and superorbital aborts as well as guidance following return from a deepspace mission. In this paper, the role of the human pilot?s ability to combine safe return abort procedures with guidance procedures has been investigated. The range capability from various abort and entry conditions is also presented

    Research study of an aircraft-contained radar zero-zero landing system, volume 2 Final report, Jan. - Dec. 1967

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    Conceptual development of long wave radar display based on processed plan position indicator and cross beam raster scan technique

    Higher diversity of Rhizobium leguminosarum biovar viciae populations in arable soils than in grass soils

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    The bacterial genetic diversity after long-term arable cultivation was compared with that under permanent grassland using replicated paired contrasts, Pea-nodulating Rhizobium leguminosarum populations were sampled from pairs of arable and grass sites at four locations in Yorkshire, United Kingdom, isolates were characterized using both chromosomal (16S-23S ribosomal DNA internal transcribed spacer PCR-restriction fragment length polymorphism) and plasmid (group-specific repC PCR amplification) markers. The diversities of chromosomal types, repC profiles, and combined genotypes were calculated using richness in types (adjusted to equal sample sizes by rarefaction), Shannon-Wiener index, and Simpson's index. The relative differences in diversity within each pair of sites were similar for all three diversity measures, Chromosomal types, repC profiles, and combined genotypes were each more diverse in arable soils than in grass soils at two of the four locations. The other comparisons showed no significant differences. We conclude that rhizobial diversity can be affected by differences between these two management regimens. Multiple regression analyses indicated that lower diversity was associated with high potential nitrogen and phosphate levels or with acidity

    Evaluating human performance modeling for system assessment: Promise and problems

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    The development and evaluation of computational human performance models is examined. An intention is to develop models which can be used to interact with system prototypes and simulations to perform system assessment. Currently LR is working on a set of models emulating cognitive, psychomotor, auditory, and visual activity for multiple operator positions of a command and control simulation system. These models, developed in conjunction with BBN Systems and Technologies, function within the simulation environment and allow for both unmanned system assessment and manned (human-in-loop) assessment of system interface and team interactions. These are relatively generic models with built-in flexibility which allows modification of some model parameters. These models have great potential for improving the efficiency and effectiveness of system design, test, and evaluation. However, the extent of the practical utility of these models is unclear. Initial verification efforts comparing model performance within the simulation to actual human operators on a similar, independent simulation have been performed and current efforts are directed at comparing human and model performance within the same simulation environment

    Selected aspects of lunar mare geology from Apollo orbital photography

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    Crater size-frequency distributions were studied (100-500 m) and are shown to provide significant integrated information concerning mare surface ages, subsurface stratigraphy, and surficial geology. Equilibrium cratering is discussed gradually reducing the relative numbers of craters smaller than 300-400 m in diameter as surfaces age and regolith thickens. Results for surface ages are in good agreement with other published crater ages. The existing correlations of large ring structures among various circular mare basins are shown to be based on criteria that are inconsistent and nonstandardized. A means of comparing equivalent ring structures in the different maria is proposed which takes into account the important characteristics of young unflooded basins (Orientale) as well as the progressive development of tectonic and volcanic features within the older flooded maria. Specific geologic aspects of several of the lunar maria are discussed and especially Mare Smythii, because of its great age and significantly different surface morphology. Lunar photographs and maps are shown

    VOCALIZATION OF THE CROCODILE SKINK, TRIBOLONOTUS GRACILIS (DE ROOY, 1909), AND EVIDENCE OF PARENTAL CARE.

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    The crocodile or spiny skinks, Tribolonotus, comprise eight secretive semi-fossorial lizards, which are generally found under vegetation in the immediate vicinity of water (Greer and Parker, 1968; O'Shea, 1991, 1994; Rogner, 1997). Tribolonotus gracilis (Figure 1) and Tribolonotus novaeguineae are restricted to New Guinea, while the remaining six species range throughout Indonesia, Manus, New Britain, Bougainville, and the Solomon Islands (McCoy, 1980; O'Shea, 1991, 1994). Because scant life history information is available for the genus Tribolonotus, the purpose of the present contribution is to document the vocalization and parental care of T. gracilis
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