3,824 research outputs found

    Pre-emphasis determination for an S-band constant bandwidth FM/FM station

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    Telemetry bands are being reassigned to UHF at 1500 and 2200 MHz. Conversion primarily requires changes in equipment used in RF link, while many of same subcarrier oscillators, mixer amplifiers, and frequency discriminators can be used

    SBASI: Actuated pyrotechnic time delay initiator

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    A precision pyrotechnic time delay initiator for missile staging was developed and tested. Incorporated in the assembly is a single bridgewire Apollo standard initiator (SBASI) for initiation, a through-bulkhead-initiator to provide isolation of the SBASI output from the delay, the pyrotechnic delay, and an output charge. An attempt was made to control both primary and secondary variables affecting functional performance of the delay initiator. Design and functional limit exploration was performed to establish tolerance levels on manufacturing and assembling operations. The test results demonstrate a 2% coefficient of variation at any one temperature and an overall 2.7% coefficient of variation throughout the temperature range of 30 to 120 F. Tests were conducted at simulated operational altitude from sea level to 200,000 feet

    Pseudo-noise test set for communication system evaluation

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    A test set for communications systems is described which includes a pseudo noise sequence generator providing a test signal that is fed to a pair of signal channels. The first channel includes a spectrum shaping filter and a conditioning amplifier. The second channel includes a variable delay circuit, a spectrum shaping filter matched to the first filter, and an amplifier. The output of the first channel was applied to the system under test. The output of the system and the output of the second channel are compared to determine the degree of distortion suffered by the test signal due to the communications system

    Method of and means for testing a tape record/playback system

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    A tape record/playback system was tested by first deriving an analog test signal and a band-limited digital reference signal from a pseudo-noise sequence generator driven by a clock signal. It recorded the signals on respective tracks of the system during operation in a record mode. During the playback mode of operation of the system, a delayed analog reference signal without time base variations was reconstructed from the played back reference signal. It was compared with the played back test signal in order to obtain an error signal that was a measure of the performance of the system

    Compact steep-spectrum sources from the S4 sample

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    We present the results of 5-GHz observations with the VLA A-array of a sample of candidate Compact Steep Spectrum sources (CSSs) selected from the S4 survey. We also estimate the symmetry parameters of high-luminosity CSSs selected from different samples of radio sources, and compare these with the larger sources of similar luminosity to understand their evolution and the consistency of the CSSs with the unified scheme for radio galaxies and quasars. The majority of CSSs are likely to be young sources advancing outwards through a dense asymmetric environment. The radio properties of CSSs are found to be consistent with the unified scheme, in which the axes of the quasars are observed close to the line of sight, while radio galaxies are observed close to the plane of the sky.Comment: accepted for publication in mnras; 8 pages, figure 1 with 21 images, and two additional figures; 2 table

    The brow-antlered deer in Burma—its distribution and status

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    Two of the three subspecies of brow-antlered deer are endangered and only the Burmese subspecies is still relatively abundant. Even so, it is a species of major concern in Burma. The authors describe the results of their surveys to determine the deer's status, the main threats to its survival and what needs to be done to conserve i

    Excursion to Ingatestone and Beggar Hill

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    Methods in Soil Analysis

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    On the Intentionality of Cultural Products: Representations of Black History As Psychological Affordances

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    A cultural-psychological analysis emphasizes the intentionality of everyday worlds: the idea that material products not only bear psychological traces of culturally constituted beliefs and desires, but also subsequently afford and promote culturally consistent understandings and actions. We applied this conceptual framework of mutual constitution in a research project using quantitative and qualitative approaches to understand the dynamic resonance between sociocultural variance in Black History Month (BHM) representations and the reproduction of racial inequality in the U.S. In studies 1 and 2, we considered whether mainstream BHM artifacts reflect the preferences and understandings of White Americans (i.e., psychological constitution of cultural worlds). Consistent with the psychological constitution hypothesis, White American participants reported more positive affect, better recognition, and greater liking for BHM representations from the schools where White Americans were the majority than BHM representations from the schools where Black students and other students of color were the majority. Moreover, as an indication of the identity relevance of BHM representations, White identification was more positively associated with judgments of positive affect and preference in response to BHM representations from White schools than BHM representations from the schools where Black students were in the majority. In studies 3 and 4, we considered whether BHM representations from different settings differentially afford support or opposition to anti-racism policies (i.e., cultural constitution of psychological experience). In support of the cultural constitution hypothesis, BHM representations typical of schools where Black students were in the majority were more effective at promoting support for anti-racism policies compared to BHM representations typical of predominately White schools and a control condition. This effect was mediated by the effect of (different) BHM representations on perception of racism. Together, these studies suggest that representations of Black History constitute cultural affordances that, depending on their source, can promote (or impede) perception of racism and anti-racism efforts. This research contributes to an emerging body of work examining the bidirectional, psychological importance of cultural products. We discuss implications for theorizing collective manifestations of mind
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