35,590 research outputs found

    Tread drum for animals

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    A device for exercising animals such as primates is described, which includes a cylindrical housing mounted for rotation about a horizontal axis of revolution and has a cylindrical treadway portion on which the animal treads while the drum is rotated by means of a motorized drive. The treadway portion of the drum includes an electrode structure with sectors being independently energizable by means of a commutator and source of potential so that an electrical shock station is created behind a running-in-place station on the moving treadway. In this manner, if the animal should fall behind its running-in-place station, it may be shocked by treading on the energized electrode structure. One end of the tread drum comprises a transparent wall for unobstructed viewing of the animal being exercised

    Dudeney\u27s Switch Puzzle

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    This is the tale of a quasi-mechanical word puzzle propounded by Sam Loyd, a famous British puzzler, to Henry Ernest Dudeney, another famous British puzzler, around the turn of the century. Dudeney is best known for his work in the field of mathematical recreations, but he was also interested in word curiosities, and the Switch Puzzle is one of many included in his book, The World\u27s Best Word Puzzles, published by the Daily News Publications Department, London, 1925

    Logological Poetry: An Editorial

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    It was Dmitri Borgmann who put the word logology into circulation. Before Language on Vacation, his first book, was published, he wrote to me: I don\u27t believe the word \u27logology\u27 has ever appeared in a book devoted to words or puzzles. I dug it out of the unabridged Oxford while searching for a suitable name for my activity

    Interviewing Ronald Wilson Reagan

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    As a rule, VIPs are likely to be interviewed only by other equal or lesser VIPs. But there is an even stronger rule, little known and indubitably of less consequence, that only VUPs are ever observed interviewing a Big Name in the literal sense, and like all bizarre aberrations in nature it is observed only rarely. I am not speaking of interviewing a Big Name in the figurative sense as Barbara Walters would do, which really means interviewing the actual person. No, I speak of interviewing only the Name itself, which in the present instance is composed of eleven distinct letters of the alphabet: A, D, E, G, I, L, N, O, R, S, and W. For the benefit of those who want a technical name for this kind of wordplay, the interviewee\u27s half of this interview is called a lipogram on the name RONALD WILSON REAGAN, which means that the interviewee utters no words except those which can be spelled using the alphabetical letters in his name

    A Study of the Conductivity of Several Conductive Polymers

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    The purpose of this thesis is to compare the conductivities of several solutions now in use in producing electroconductive paper. The testing procedure involved the use of a Kiethyl 610 B electrometer with two aluminum discs for conductance through the sheet and two brass strips for conductance across the sheet. Attempts were made to improve the conductance of the solution by the addition of surface agents in the belief that this would lead to better dispersion and thus to better film continuity. No effective method was found to improve the conductivity of a solution of given concentration. Increasing the concentration from 10% to 30% however did give substantial improvements in conductivity

    Some Bright Stars with Smooth Continua for Calibrating the Response of High Resolution Spectrographs

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    When characterizing a high resolution echelle spectrograph, for instance for precise Doppler work, it is useful to observe featureless sources such as quartz lamps or hot stars to determine the response of the instrument. Such sources provide a way to determine the blaze function of the orders, pixel-to-pixel variations in the detector, fringing in the system, and other important characteristics. In practice, however, many B or early A stars do not provide a smooth continuum, whether because they are not rotating rapidly enough or for some other reason. In fact, we have found that published rotational velocities and temperatures are not a specific and sensitive guide to whether a star's continuum will be smooth. A useful resource for observers, therefore, is a list of "good" hot stars: bright, blue stars known empirically to have no lines or other spectral features beyond the Balmer series with minima below 95% of the continuum. We have compiled a list of such stars visible from Northern Hemisphere telescopes. This list includes all stars listed in the Yale Bright Star Catalog (Hoffleit & Jaschek 1991) as being single with V 175 km/s, and declination > -30, and many other hot stars that we have found useful for calibration purposes. The list here of "bad" stars may also be of interest in studies of hot, slowly rotating stars

    Astrophysical Insights into Radial Velocity Jitter from an Analysis of 600 Planet-search Stars

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    Radial velocity (RV) detection of planets is hampered by astrophysical processes on the surfaces of stars that induce a stochastic signal, or "jitter," which can drown out or even mimic planetary signals. Here, we empirically and carefully measure the RV jitter of more than 600 stars from the California Planet Search sample on a star by star basis. As part of this process, we explore the activity–RV correlation of stellar cycles and include appendices listing every ostensibly companion-induced signal we removed and every activity cycle we noted. We then use precise stellar properties from Brewer et al. to separate the sample into bins of stellar mass and examine trends with activity and with evolutionary state. We find that RV jitter tracks stellar evolution and that in general, stars evolve through different stages of RV jitter: the jitter in younger stars is driven by magnetic activity, while the jitter in older stars is convectively driven and dominated by granulation and oscillations. We identify the "jitter minimum"—where activity-driven and convectively driven jitter have similar amplitudes—for stars between 0.7 and 1.7 M⊙ and find that more-massive stars reach this jitter minimum later in their lifetime, in the subgiant or even giant phases. Finally, we comment on how these results can inform future RV efforts, from prioritization of follow-up targets from transit surveys like TESS to target selection of future RV surveys

    Apollo docking test device design study final report

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    Docking simulation system for confirming Apollo probe design and drogue docking mechanisms under simulated space condition

    CF6 jet engine performance improvement: High pressure turbine roundness

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    An improved high pressure turbine stator reducing fuel consumption in current CF6-50 turbofan engines was developed. The feasibility of the roundness and clearance response improvements was demonstrated. Application of these improvements will result in a cruise SFC reduction of 0.22 percent for new engines. For high time engines, the improved roundness and response characteristics results in an 0.5 percent reduction in cruise SFC. A basic life capability of the improved HP turbine stator in over 800 simulated flight cycles without any sign of significant distress is shown
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