127 research outputs found

    Microscopic Black Hole Pairs in Highly-Excited States

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    We consider the quantum mechanics of a system consisting of two identical, Planck-size Schwarzschild black holes revolving around their common center of mass. We find that even in a very highly-excited state such a system has very sharp, discrete energy eigenstates, and the system performs very rapid transitions from a one stationary state to another. For instance, when the system is in the 100th excited state, the life times of the energy eigenstates are of the order of 10−3010^{-30} s, and the energies of gravitons released in transitions between nearby states are of the order of 102210^{22} eV.Comment: 22 pages, 3 figures, uses RevTe

    Reliable Detection of Rotor Bars Breakage in Induction Motors via MUSIC and ZSC Methods

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    "(c) 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works"[EN] Induction motors are used in a variety of industrial applications where frequent startup cycles are required. In those cases, it is necessary to apply sophisticated signal processing analysis methods in order to reliably follow the time evolution of fault-related harmonics in the signal. In this paper, the zero-sequence current (ZSC) is analyzed using the high-resolution spectral method of multiple signal classification. The analysis of the ZSC signal has proved to have several advantages over the analysis of a single-phase current waveform. The method is validated through simulation and experimental results. The simulations are carried out for a 1.1-MW and a 4-kW induction motors under finite element analysis. Experimentation is performed on a healthy motor, a motor with one broken rotor bar, and a motor with two broken rotor bars. The analysis results are satisfactory since the proposed methodology reliably detects the broken rotor bar fault and its severity, both during transient and steady-state operation of the induction motor.This work was supported in part by the Spanish Ministerio de Economia y Competitividad (MINECO) and in part by the FEDER program in the framework of the Proyectos I+D del Subprograma de Generacion de Conocimiento, Programa Estatal de Fomento de la Investigacion Cientifica y Tecnica de Excelencia under Grant DPI2014-52842-P.Morinigo-Sotelo, D.; Romero-Troncoso, R.; Panagiotou, P.; Antonino-Daviu, J.; Gyftakis, KN. (2018). Reliable Detection of Rotor Bars Breakage in Induction Motors via MUSIC and ZSC Methods. IEEE Transactions on Industry Applications. 54(2):1224-1234. https://doi.org/10.1109/TIA.2017.2764846S1224123454

    Can metacognitive interventions improve insight in schizophrenia spectrum disorders? A systematic review and meta-analysis

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    Background: Patients with schizophrenia spectrum disorders (SSD) tend to lack insight, which is linked to poor outcomes. The effect size of previous treatments on insight changes in SSD has been small. Metacognitive interventions may improve insight in SSD, although this remains unproved. Methods: We carried out a systematic review and meta-analysis of randomized controlled trials (RCTs) to examine the effects of metacognitive interventions designed for SSD, namely Metacognitive Training (MCT) and Metacognitive Reflection and Insight Therapy (MERIT), on changes in cognitive and clinical insight at post-treatment and at follow-up. Results: Twelve RCTs, including 10 MCT RCTs (n = 717 participants) and two MERIT trials (n = 90), were selected, totalling N = 807 participants. Regarding cognitive insight six RCTs (n = 443) highlighted a medium effect of MCT on self-reflectiveness at post-treatment, d = 0.46, p < 0.01, and at follow-up, d = 0.30, p < 0.01. There was a small effect of MCT on self-certainty at post-treatment, d = −0.23, p = 0.03, but not at follow-up. MCT was superior to controls on an overall Composite Index of cognitive insight at post-treatment, d = 1.11, p < 0.01, and at follow-up, d = 0.86, p = 0.03, although we found evidence of heterogeneity. Of five MCT trials on clinical insight (n = 244 participants), which could not be meta-analysed, four of them favoured MCT compared v. control. The two MERIT trials reported conflicting results. Conclusions: Metacognitive interventions, particularly Metacognitive Training, appear to improve insight in patients with SSD, especially cognitive insight shortly after treatment. Further long-term RCTs are needed to establish whether these metacognitive interventions-related insight changes are sustained over a longer time period and result in better outcomes

    Very Accurate Time-Frequency Representation of Induction Motors Harmonics for Fault Diagnosis Under Load Variations

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    Induction motors work under steady-state in many applications. Nevertheless, in some cases they experience periodic load fluctuations, which generate constant frequency harmonics close to variable frequency bar breakage harmonics. In these cases, time-frequency (t-f) transforms are better suited than steady-state analysis since the fault harmonic frequencies change in time. Even if the healthy and faulty frequencies do not overlap in the spectrum, if the speed is unknown, it is difficult to distinguish the constant frequency healthy harmonic from the variable frequency bar breakage harmonic. On the other hand, transient techniques present in technical literature are not precise enough to deal with both the changing frequency of the bar breakage harmonic and a close constant frequency (as the one generated by most of the periodic load fluctuations). To achieve reliable results under these challenging situations, a very precise time-frequency transform must be used, enabling to simultaneously draw the constant and variable frequencies, even if they are very close in the t-f plane. The Dragon-Transform is here proposed to address the problem. It is shown through simulation and experimental results, how it enables to very accurately plot up to five faulty harmonics evolutions, distinguishing at the same time the constant frequency of the load oscillation, traced as a very thin horizontal line. Precision is so high that even the oscillations caused by ripple effect can be observed for the first time in technical literature, enhancing the reliability of the diagnosis performed, and opening the path for a true solution of the problem

    Adiponectin-Mediated Analgesia and AntiInflammatory Effects in Rat

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    The adipose tissue-derived protein, adiponectin, has significant anti-inflammatory properties in a variety of disease conditions. Recent evidence that adiponectin and its receptors (AdipoR1 and AdipoR2) are expressed in central nervous system, suggests that it may also have a central modulatory role in pain and inflammation. This study set out to investigate the effects of exogenously applied recombinant adiponectin (via intrathecal and intraplantar routes; 10–5000 ng) on the development of peripheral inflammation (paw oedema) and pain hypersensitivity in the rat carrageenan model of inflammation. Expression of adiponectin, AdipoR1 and AdipoR2 mRNA and protein was characterised in dorsal spinal cord using real-time polymerase chain reaction (PCR) and Western blotting. AdipoR1 and AdipoR2 mRNA and protein were found to be constitutively expressed in dorsal spinal cord, but no change in mRNA expression levels was detected in response to carrageenan-induced inflammation. Adiponectin mRNA, but not protein, was detected in dorsal spinal cord, although levels were very low. Intrathecal administration of adiponectin, both pre- and 3 hours post-carrageenan, significantly attenuated thermal hyperalgesia and mechanical hypersensitivity. Intrathecal administration of adiponectin post-carrageenan also reduced peripheral inflammation. Intraplantar administration of adiponectin pre-carrageenan dose-dependently reduced thermal hyperalgesia but had no effect on mechanical hypersensitivity and peripheral inflammation. These results show that adiponectin functions both peripherally and centrally at the spinal cord level, likely through activation of AdipoRs to modulate pain and peripheral inflammation. These data suggest that adiponectin receptors may be a novel therapeutic target for pain modulation
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