537 research outputs found

    Fault tolerant motor drive system with redundancy for critical applications

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    Some of the recent research activities in the area of electric motor drives for critical applications (such as aerospace and nuclear power plants) are focused on looking at various motor and drive topologies. This paper presents a motor drive system, which provides an inverter topology for three-phase motors, and also proposes an increased redundancy. The paper develops a simulation model for the complete drive system including synthetic faults. In addition, the hardware details including the implementation of DSP based motor controller, inverter module, and brushless PM motor system are provided and some experimental results are presented.N. Ertugrul, W. Soong, G. Dostal and D. Saxo

    Discharges of past flood events based on historical river profiles

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    International audienceThis paper presents a case study to estimate peak discharges of extreme flood events of Neckar River in south-western Germany during the 19th century. It was carried out within the BMBF research project RIMAX (Risk Management of Extreme Flood Events). The discharge estimations were made for the flood events of 1824 and 1882 based on historical cross profiles. The 1-D model Hydrologic Engineering Centers River Analysis System (HEC-RAS) was applied with different roughness coefficients. The results are compared (i) with contemporary historical calculations and (ii) in the case of a flood event in 1824 with the discharge simulation by the water balance model LARSIM (Large Area Runoff Simulation Model). These calculations are matched by the HEC-RAS simulation based on the standard roughness coefficients

    Full characterization of vibrational coherence in a porphyrin chromophore by two-dimensional electronic spectroscopy

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    In this work we present experimental and calculated two-dimensional electronic spectra for a 5,15-bisalkynyl porphyrin chromophore. The lowest energy electronic Qy transition couples mainly to a single 380 cmā€“1 vibrational mode. The two-dimensional electronic spectra reveal diagonal and cross peaks which oscillate as a function of population time. We analyze both the amplitude and phase distribution of this main vibronic transition as a function of excitation and detection frequencies. Even though Feynman diagrams provide a good indication of where the amplitude of the oscillating components are located in the excitation-detection plane, other factors also affect this distribution. Specifically, the oscillation corresponding to each Feynman diagram is expected to have a phase that is a function of excitation and detection frequencies. Therefore, the overall phase of the experimentally observed oscillation will reflect this phase dependence. Another consequence is that the overall oscillation amplitude can show interference patterns resulting from overlapping contributions from neighboring Feynman diagrams. These observations are consistently reproduced through simulations based on third order perturbation theory coupled to a spectral density described by a Brownian oscillator model

    Power Spectrum Analysis of Physikalisch-Technische Bundesanstalt Decay-Rate Data: Evidence for Solar Rotational Modulation

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    Evidence for an anomalous annual periodicity in certain nuclear decay data has led to speculation concerning a possible solar influence on nuclear processes. We have recently analyzed data concerning the decay rates of Cl-36 and Si-32, acquired at the Brookhaven National Laboratory (BNL), to search for evidence that might be indicative of a process involving solar rotation. Smoothing of the power spectrum by weighted-running-mean analysis leads to a significant peak at frequency 11.18/yr, which is lower than the equatorial synodic rotation rates of the convection and radiative zones. This article concerns measurements of the decay rates of Ra-226 acquired at the Physikalisch-Technische Bundesanstalt (PTB) in Germany. We find that a similar (but not identical) analysis yields a significant peak in the PTB dataset at frequency 11.21/yr, and a peak in the BNL dataset at 11.25/yr. The change in the BNL result is not significant since the uncertainties in the BNL and PTB analyses are estimated to be 0.13/yr and 0.07/yr, respectively. Combining the two running means by forming the joint power statistic leads to a highly significant peak at frequency 11.23/yr. We comment briefly on the possible implications of these results for solar physics and for particle physics.Comment: 15 pages, 13 figure

    Switched-current filter structure for synthesizing arbitrary characteristics based on follow-the-leader feedback configuration

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    This document is the Accepted Manuscript version of the following article: Wenshan Zhao, Yigang He, and Yichuang Sun, ā€˜Switched-current filter structure for synthesizing arbitrary characteristics based on follow-the-leader feedback configurationā€™, Analog Integrated Circuits and Signal Processing, (2015), Vol. 82 (2): 479-486. The version of record is available online at doi: 10.1007/s10470-014-0477-8 Ā© Springer Science+Business Media New York 2015Peer reviewedFinal Accepted Versio

    Coulomb fragmentation and Coulomb fission of relativistic heavy-ions and related nuclear structure aspects

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    The Coulomb excitation of 208Pb projectiles has been studied at an energy of 640 A MeV. Cross sections for the excitation of the two-phonon giant dipole resonance were measured for different targets, and show clear evidence for a two-step electromagnetic excitation mechanism. The experimental cross sections exceed those calculated in the harmonic oscillator approximation by a factor of 1.33 Ā± 0.16. The deduced 27-decay probability is consistent with the expectation in the harmonic limit. Finally, the excitation of the two-phonon giant dipole resonance in the deformed and fissile nucleus 238U is discussed

    Heideggerā€™s Underdeveloped Conception of the Undistinguishedness (Indifferenz) of Everyday Human Existence

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    This chapter provides an interpretation of the early Heideggerā€™s underdeveloped conception of the undistinguishedness of everyday human existence in Being and Time. After explaining why certain translation choices of some key terms in this text are interpretively and philosophically important, I first provide a concise argument for why the social constitution interpretation of the relation between ownedness and unownedness makes better overall sense of Heideggerā€™s ambivalent attitude toward the social constitution of the human being than the standard existentialist interpretation of this relation. I then proceed to the heart of this chapter, which develops his inchoate conception of the undistinguishedness of everydayness by arguing that it specifies the third distinctive mode of concrete human existence in addition to ownedness and unownedness. Accordingly, I show how unownedness is actually a generic phenomenon with two distinct species, namely, undistinguishedness and disownedness, which are at once closely related to, but also differ in significant respects from, each other. Consequently, instead of taking for granted a one-dimensional and mutually exclusive opposition between ā€˜authenticityā€™ and ā€˜inauthenticityā€™, I argue that we should adopt a two-dimensional and more nuanced understanding of the relations among undistinguishedness, disownedness, and ownedness that intersects with Heideggerā€™s underappreciated distinction between genuineness and ungenuineness. After raising and replying to some objections to this interpretation of undistinguishedness, I conclude this chapter by briefly sketching three of its philosophical consequences and pointing out its potential as an important resource for contemporary social theories

    Differential Roles of Cardiomyocyte and Macrophage Peroxisome Proliferatorā€“Activated Receptor Ī³ in Cardiac Fibrosis

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    OBJECTIVEā€”Cardiac fibrosis is an important component of diabetic cardiomyopathy. Peroxisome proliferatorā€“activated receptor Ī³ (PPARĪ³) ligands repress proinflammatory gene expression, including that of osteopontin, a known contributor to the development of myocardial fibrosis. We thus investigated the hypothesis that PPARĪ³ ligands could attenuate cardiac fibrosis
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