6,271 research outputs found

    Modulator for tone and binary signals

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    Tones and binary information are transmitted as phase variations on a carrier wave of constant amplitude and frequency. The carrier and tones are applied to a balanced modulator for deriving an output signal including a pair of sidebands relative to the carrier. The carrier is phase modulated by a digital signal so that it is + or - 90 deg out of phase with the predetermined phase of the carrier. The carrier is combined in an algebraic summing device with the phase modulated signal and the balanced modulator output signal. The output of the algebraic summing device is hard limited to derive a constant amplitude and frequency signal having very narrow bandwidth requirements. At a receiver, the tones and binary data are detected with a phase locked loop having a voltage controlled oscillator driving a pair of orthogonal detection channels

    Photometry of GSC 762-110, a new triple-mode radially pulsating star

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    Stars pulsating in three radial modes are very rare; only three examples are known in the Galaxy. These stars are very useful since their periods may be measured very precisely, and this will constrain the global stellar parameters and the models of the star's interior. The purpose of this paper is to present a new example of the class of triple-mode radial pulsators. A search for candidate multi-mode pulsators was carried out in public survey data. Time-series photometry of one of the candidates, GSC 762-110, was performed. GSC 762-110 was found to be a triple-mode radial pulsator, with a fundamental period of 0.1945d and period ratios of 0.7641 and 0.8012. In addition two non-radial modes were found, for which the amplitude has diminished considerably over the last few years.Comment: Accepted for publication in Astronomy & Astrophysic

    An evaluation of aft-end ignition for solid propellant rocket motors

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    Performance evaluation of solid propellant rocket motor ignition to determine igniter design and parameters to avoid overpressurizatio

    School Counselor Satisfaction with their Graduate Training: A Survey of East Kentucky Counselors

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    A report submitted by Trey J. Fitch to the Research and Creative Productions Committee in 2001 on the many different roles of school counselors in Eastern Kentucky

    An evaluation of the post-ignition unblocking behavior of solid propellant aft-end ignition systems Final report

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    Determining postignition interactions between igniter and main motor flow by aft-end heated air simulation of solid propellant exhaus

    Memory based on abstraction for dynamic fitness functions

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    Copyright @ Springer-Verlag Berlin Heidelberg 2008.This paper proposes a memory scheme based on abstraction for evolutionary algorithms to address dynamic optimization problems. In this memory scheme, the memory does not store good solutions as themselves but as their abstraction, i.e., their approximate location in the search space. When the environment changes, the stored abstraction information is extracted to generate new individuals into the population. Experiments are carried out to validate the abstraction based memory scheme. The results show the efficiency of the abstraction based memory scheme for evolutionary algorithms in dynamic environments.This work was supported by the Engineering and Physical Sciences Research Council (EPSRC) of UK under Grant No. EP/E060722/1

    PTSD Among Working Women in a Developing Country

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    https://digitalscholarship.unlv.edu/wrin_briefs/1004/thumbnail.jp
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