5,643 research outputs found

    Characterization of three types of silicon solar cells for SEPS Deep Space Mission. Volume 3: Current-voltage characteristics of spectrolab sculptured BSR/P+ (K7), BSR/P+ (K6.5) and BSR (K4.5) cells as a function of temperature and intensity

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    Three types of high performance silicon solar cells, sculptured BSR/P+(K7), BSR/P+(K6.5) and BSR(K4.5) manufactured by Spectrolab were evaluated for their low temperature and low intensity performance. Sixteen cells of each type were subjected to 11 temperatures and 9 intensities. The sculptured BSR/P+(K7) cells provided the greatest maximum power output both at 1 AU and at LTLI conditions. The average efficiencies of this cell were 14.4 percent at 1 SC/+25 deg C and 18.5 percent at 0.086 SC/-100 deg C

    NASA catalogue of lunar nomenclature

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    Lunar nomenclature is cataloged. It includes letter designations for subsidiary craters, and uses a more familiar spelling from eight names. The listed features are divided into three main groups for cataloging purposes, namely: (1) craters, (2) noncrater features; and (3) minor and miscellaneous features

    Ultrashort pulses and short-pulse equations in (2+1)−(2+1)-dimensions

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    In this paper, we derive and study two versions of the short pulse equation (SPE) in (2+1)−(2+1)-dimensions. Using Maxwell's equations as a starting point, and suitable Kramers-Kronig formulas for the permittivity and permeability of the medium, which are relevant, e.g., to left-handed metamaterials and dielectric slab waveguides, we employ a multiple scales technique to obtain the relevant models. General properties of the resulting (2+1)(2+1)-dimensional SPEs, including fundamental conservation laws, as well as the Lagrangian and Hamiltonian structure and numerical simulations for one- and two-dimensional initial data, are presented. Ultrashort 1D breathers appear to be fairly robust, while rather general two-dimensional localized initial conditions are transformed into quasi-one-dimensional dispersing waveforms

    Evaluation of direct current motors in vacuum

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    Simulated space environment evaluation of direct current motor material

    Apollo experiment S-217 IR/radar study of Apollo data

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    An experiment using Earth based remote sensing radar, infrared eclipse, and color difference data to deduce surface properties not visible in Apollo photography is reported. The Earth based data provided information on the small scale (centimeter sized) blockiness and on the surface chemical composition (titanium and iron contents) of the lunar surface. These deduced surface properties complemented the new Apollo photography, leading to refined geologic interpretations of the lunar surface

    Globular Clusters and X-ray Point Sources in Centaurus A (NGC 5128)

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    We detect 353 X-ray point sources, mostly low-mass X-ray binaries (LMXBs), in four Chandra observations of Centaurus A (NGC 5128), the nearest giant early-type galaxy, and correlate this point source population with the largest available ensemble of confirmed and likely globular clusters associated with this galaxy. Of the X-ray sources, 31 are coincident with 30 globular clusters that are confirmed members of the galaxy by radial velocity measurement (2 X-ray sources match one globular cluster within our search radius), while 1 X-ray source coincides with a globular cluster resolved by HST images. Another 36 X-ray point sources match probable, but spectroscopically unconfirmed, globular cluster candidates. The color distribution of globular clusters and cluster candidates in Cen A is bimodal, and the probability that a red, metal rich GC candidate contains an LMXB is at least 1.7 times that of a blue, metal poor one. If we consider only spectroscopically confirmed GCs, this ratio increases to ~3. We find that LMXBs appear preferentially in more luminous (massive) GCs. These two effects are independent, and the latter is likely a consequence of enhanced dynamical encounter rates in more massive clusters which have on average denser cores. The X-ray luminosity functions of the LMXBs found in GCs and of those that are unmatched with GCs reveal similar underlying populations, though there is some indication that fewer X-ray faint LMXBs are found in globular clusters than X-ray bright ones. Our results agree with previous observations of the connection of GCs and LMXBs in early-type galaxies and extend previous work on Centaurus A.Comment: 34 pages, 10 figures, 2 tables, Accepted for Publication in The Astrophysical Journa

    Great Yorkshire Livestock Show Attendees’ Attitudes about Agriculture

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    The purpose of our research was to determine if attending a U.K. livestock show changed attendees’ attitudes about agriculture and to compare those changes in attitudes to attendees of a U.S. state fair similar in size and dynamic. The sample was livestock show attendees at the Great Yorkshire Show (GYS). The mixed-method design included a then and now semantic differential scale with bipolar adjective pairs to measure attendees’ attitudes about agriculture before and after the experience and qualitative interviews with photo elicitation to learn about how attendees developed attitudes about agriculture. Participants had positive attitudes about agriculture before they attended the Show and had more positive attitudes after attending. Participants had more positive attitudes before and after attending the Show than did California State Fair attendees. In addition, participants lacked prior experiences with agriculture, but attending the GYS provided them the opportunity to develop positive attitudes through cognitive, behavioral, and environmental factors. Fair attendance should be promoted because they provide unique opportunities for experiential learning and U.S. fairs should adopt experiential tactics used at the GYS. Further research is needed to better understand how GYS attendees developed positive attitudes about agriculture prior to attending the Show and what elements of the GYS experience were most influential to attendees’ attitude development

    Emergence of classicality in small number entangled systems

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    We show the transition from a fully quantized interaction to a semiclassical one in entangled small number quantum systems using the quantum trajectories approach. In particular, we simulate the microwave Ramsey zones used in Rydberg atom interferometry, filling in the gap between the strongly entangling Jaynes Cummings evolution and the semiclassical rotation of the atomic internal states. We also correlate the information flowing with leaking photons to the entanglement generation between cavity field and flying atom and detail the roles played by the strong dissipation and the external driving force in preserving atomic coherence through the interaction.Comment: 4 pages, 6 figure

    Fractional Quantum Hall Effect and vortex lattices

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    It is demonstrated that all observed fractions at moderate Landau level fillings for the quantum Hall effect can be obtained without recourse to the phenomenological concept of composite fermions. The possibility to have the special topologically nontrivial many-electron wave functions is considered. Their group classification indicates the special values of of electron density in the ground states separated by a gap from excited states

    Reality in quantum mechanics, Extended Everett Concept, and consciousness

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    Conceptual problems in quantum mechanics result from the specific quantum concept of reality and require, for their solution, including the observer's consciousness into quantum theory of measurements. Most naturally this is achieved in the framework of Everett's "many-worlds interpretation" of quantum mechanics. According to this interpretation, various classical alternatives are perceived by consciousness separately from each other. In the Extended Everett Concept (EEC) proposed by the present author, the separation of the alternatives is identified with the phenomenon of consciousness. This explains classical character of the alternatives and unusual manifestations of consciousness arising "at the edge of consciousness" (i.e. in sleep or trance) when its access to "other alternative classical realities" (other Everett's worlds) becomes feasible. Because of reversibility of quantum evolution in EEC, all time moments in the quantum world are equivalent while the impression of flow of time appears only in consciousness. If it is assumed that consciousness may influence onto probabilities of alternatives (which is consistent in case of infinitely many Everett's worlds), EEC explains free will, "probabilistic miracles" (observing low-probability events) and decreasing entropy in the sphere of life.Comment: 17 pages, 2 figures in EP
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