7,189 research outputs found

    Symmetry violations at BABAR

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    Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Published under licence by IOP Publishing Ltd.2014 J. Phys.: Conf. Ser. 556 012042 (http://iopscience.iop.org/1742-6596/556/1/012042

    A survey of electric and hybrid vehicle simulation programs

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    Results of a survey conducted within the United States to determine the extent of development and capabilities of automotive performance simulation programs suitable for electric and hybrid vehicle studies are summarized. Altogether, 111 programs were identified as being in a usable state. The complexity of the existing programs spans a range from a page of simple desktop calculator instructions to 300,000 lines of a high-level programming language. The capability to simulate electric vehicles was most common, heat-engines second, and hybrid vehicles least common. Batch-operated programs are slightly more common than interactive ones, and one-third can be operated in either mode. The most commonly used language was FORTRAN, the language typically used by engineers. The higher-level simulation languages (e.g. SIMSCRIPT, GPSS, SIMULA) used by "model builders" were conspicuously lacking

    A survey of electric and hybrid vehicle simulation programs, volume 1

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    Development and capabilities of automotive performance simulation programs suitable for electric and hybrid vehicle studies are considered

    A decade of ejecta dust formation in the Type IIn SN 2005ip

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    In order to understand the contribution of core-collapse supernovae to the dust budget of the early universe, it is important to understand not only the mass of dust that can form in core-collapse supernovae but also the location and rate of dust formation. SN 2005ip is of particular interest since dust has been inferred to have formed in both the ejecta and the post-shock region behind the radiative reverse shock. We have collated eight optical archival spectra that span the lifetime of SN 2005ip and we additionally present a new X-shooter optical-near-IR spectrum of SN 2005ip at 4075d post-discovery. Using the Monte Carlo line transfer code DAMOCLES, we have modelled the blueshifted broad and intermediate width Hα\alpha, Hβ\beta and He I lines from 48d to 4075d post-discovery using an ejecta dust model. We find that dust in the ejecta can account for the asymmetries observed in the broad and intermediate width Hα\alpha, Hβ\beta and He I line profiles at all epochs and that it is not necessary to invoke post-shock dust formation to explain the blueshifting observed in the intermediate width post-shock lines. Using a Bayesian approach, we have determined the evolution of the ejecta dust mass in SN 2005ip over 10 years presuming an ejecta dust model, with an increasing dust mass from ~10−8^{-8} M⊙_{\odot} at 48d to a current dust mass of ∼\sim0.1 M⊙_{\odot}.Comment: Accepted by MNRAS, 17 pages, 11 figures. Author accepted manuscript. Accepted on 04/03/19. Deposited on 07/03/1

    Asynchronous response of coupled pacemaker neurons

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    We study a network model of two conductance-based pacemaker neurons of differing natural frequency, coupled with either mutual excitation or inhibition, and receiving shared random inhibitory synaptic input. The networks may phase-lock spike-to-spike for strong mutual coupling. But the shared input can desynchronize the locked spike-pairs by selectively eliminating the lagging spike or modulating its timing with respect to the leading spike depending on their separation time window. Such loss of synchrony is also found in a large network of sparsely coupled heterogeneous spiking neurons receiving shared input.Comment: 11 pages, 4 figures. To appear in Phys. Rev. Let

    Compounds with a ‘stuffed’ anti-bixbyite-type structure, analysed in terms of the Zintl–Klemm and coordination-defect concepts

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    Compounds with a ‘stuffed anti-bixbyite’ structure, such as Li3AlN2, were analysed in terms of both the extended Zintl–Klemm concept and the coordination-defect concept. For the first time, inorganic crystal structures are seen as a set of ‘multiple resonance structures’ (Klemm pseudo-structures) which co-exist as the result of unexpected electron transfers between any species pair comprising either like or unlike atoms, cations or anions. If this is the driving force controlling crystal structures, the conventional oxidation states assigned to cations and anions lose some of their usefulness

    A survey of electric and hybrid vehicles simulation programs. Volume 2: Questionnaire responses

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    The data received in a survey conducted within the United States to determine the extent of development and capabilities of automotive performance simulation programs suitable for electric and hybrid vehicle studies are presented. The survey was conducted for the Department of Energy by NASA's Jet Propulsion Laboratory. Volume 1 of this report summarizes and discusses the results contained in Volume 2

    Constraining early-time dust formation in core-collapse supernovae

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    There is currently a severe discrepancy between theoretical models of dust formation in core-collapse supernovae (CCSNe), which predict ≳0.01\gtrsim 0.01 M⊙_\odot of ejecta dust forming within ∼1000\sim 1000 days, and observations at these epochs, which infer much lower masses. We demonstrate that, in the optically thin case, these low dust masses are robust despite significant observational and model uncertainties. For a sample of 11 well-observed CCSNe, no plausible model reaches carbon dust masses above 10−410^{-4} M⊙_\odot, or silicate masses above ∼10−3\sim 10^{-3} M⊙_\odot. Optically thick models can accommodate larger dust masses, but the dust must be clumped and have a low (<0.1<0.1) covering fraction to avoid conflict with data at optical wavelengths. These values are insufficient to reproduce the observed infrared fluxes, and the required covering fraction varies not only between SNe but between epochs for the same object. The difficulty in reconciling large dust masses with early-time observations of CCSNe, combined with well-established detections of comparably large dust masses in supernova remnants, suggests that a mechanism for late-time dust formation is necessary.Comment: 14 pages, 13 figures. MNRAS accepted 10/07/2

    DEVELOPMENT OF A CRITERION METHOD TO DETERMINE PEAK MECHANICAL POWER OUTPUT IN A COUNTERMOVEMENT JUMP

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    The ability of players to repeatedly generate high levels of muscular power is a key determinant for success in many sports. Variations of the countermovement vertical jump (CMJ) have long been used as a means of measuring lower body power (LBP) (Fox and Mathews 1972). The criterion method of measuring of LBP is based on performance in a CMJ off a force platform (FP) (Hatze, 1999). Instantaneous power is determined from the product of the vertical ground reaction force (VGRF) and the velocity of the whole body centre of gravity, velocity being derived by the integration of the resultant VGRF. However, there seems to be no published standard protocol for the criterion method. The purpose of this study was to establish a standard protocol for the criterion method

    Extended Huckel theory for bandstructure, chemistry, and transport. II. Silicon

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    In this second paper, we develop transferable semi-empirical parameters for the technologically important material, silicon, using Extended Huckel Theory (EHT) to calculate its electronic structure. The EHT-parameters areoptimized to experimental target values of the band dispersion of bulk-silicon. We obtain a very good quantitative match to the bandstructure characteristics such as bandedges and effective masses, which are competitive with the values obtained within an sp3d5s∗sp^3 d^5 s^* orthogonal-tight binding model for silicon. The transferability of the parameters is investigated applying them to different physical and chemical environments by calculating the bandstructure of two reconstructed surfaces with different orientations: Si(100) (2x1) and Si(111) (2x1). The reproduced π\pi- and π∗\pi^*-surface bands agree in part quantitatively with DFT-GW calculations and PES/IPES experiments demonstrating their robustness to environmental changes. We further apply the silicon parameters to describe the 1D band dispersion of a unrelaxed rectangular silicon nanowire (SiNW) and demonstrate the EHT-approach of surface passivation using hydrogen. Our EHT-parameters thus provide a quantitative model of bulk-silicon and silicon-based materials such as contacts and surfaces, which are essential ingredients towards a quantitative quantum transport simulation through silicon-based heterostructures.Comment: 9 pages, 9 figure
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