1,969 research outputs found

    Derailment-based fault tree analysis on risk management of railway turnout systems

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    Railway turnouts are fundamental mechanical infrastructures, which allow a rolling stock to divert one direction to another. As those are of a large number of engineering subsystems, e.g. track, signalling, earthworks, these particular sub-systems are expected to induce high potential through various kind of failure mechanisms. This could be a cause of any catastrophic event. A derailment, one of undesirable events in railway operation, often results, albeit rare occurs, in damaging to rolling stock, railway infrastructure and disrupt service, and has the potential to cause casualties and even loss of lives. As a result, it is quite significant that a well-designed risk analysis is performed to create awareness of hazards and to identify what parts of the systems may be at risk. This study will focus on all types of environment based failures as a result of numerous contributing factors noted officially as accident reports. This risk analysis is designed to help industry to minimise the occurrence of accidents at railway turnouts. The methodology of the study relies on accurate assessment of derailment likelihood, and is based on statistical multiple factors-integrated accident rate analysis. The study is prepared in the way of establishing product risks and faults, and showing the impact of potential process by Boolean algebra

    The cytotoxic evaluation of mineral trioxide aggregate and bioaggregate in the subcutaneous connective tissue of rats

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    Objectives: The purpose of this study was to evaluate and compare the cytotoxic effects of ProRoot MTA and DiaRoot BA, a bioceramic nanoparticulate cement, on subcutaneous rat tissue. Study D esign: Fifty Sprouge Dawley rats were used in this study. Polyethylene tubes filled with ProRoot MTA and DiaRoot BioAggregate, along with a control group of empty, were implanted into dorsal connective tissue of rats for 7, 15, 30, 60, and 90 days. After estimated time intervals the rats were sacrificed. The specimens were fixed, stained with hematoxylin and eosin, and then evaluated under a light microscope for inflammatory reactions and mineralization. Results: All groups evoked a severe to moderate chronic inflammatory reaction at 7 and 15 days, which decreased with time. Both the MTA and BioAggregate groups showed similar inflammatory reactions, except at 90 days when MTA showed statistically significant greater inflammation (p>0.05). The MTA group showed foreign body reaction at all times. Compared to BioAggregate, MTA showed significantly more foreign body reaction at 60 and 90 days (p<0.0001). After 30 days foreign body reaction of BioAggregate decreased significantly. Both MTA and BioAggregate groups showed similar necrosis at 7 and 15 days (p=0.094 and p=0.186 respectively). No necrosis was observed after 15 days. Similarly there was no fibrosis after 30 days for both MTA and BioAggregate groups (p>0.05). Conclusions: Since DiaRoot BioAggregate showed significantly better results than MTA, we can conclude that it is more biocompatible. However, further studies are required to confirm this result

    Facilitating joint attention with salient pointing in interactions involving children with autism spectrum disorder

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    Children with autism spectrum disorder (ASD) reportedly have difficulties in responding to bids for joint attention, notably in following pointing gestures. Previous studies have predominantly built on structured observation measures and predefined coding categories to measure children’s responsiveness to gestures. However, how these gestures are designed and what detailed interactional work they can accomplish have received less attention. In this paper, we use a multimodal approach to conversation analysis (CA) to investigate how educators design their use of pointing in interactions involving school-aged children with ASD or autistic features. The analysis shows that pointing had specific sequential implications for the children beyond mere attention sharing. Occasionally, the co-occurring talk and pointing led to ambiguities when a child was interpreting their interactional connotations, specifically when the pointing gesture lacked salience. The study demonstrates that the CA approach can increase understanding of how to facilitate the establishment of joint attention

    The 55 Cancri Planetary System: Fully Self-Consistent N-body Constraints and a Dynamical Analysis

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    We present an updated study of the planets known to orbit 55 Cancri A using 1,418 high-precision radial velocity observations from four observatories (Lick, Keck, Hobby-Eberly Telescope, Harlan J. Smith Telescope) and transit time/durations for the inner-most planet, 55 Cancri "e" (Winn et al. 2011). We provide the first posterior sample for the masses and orbital parameters based on self-consistent n-body orbital solutions for the 55 Cancri planets, all of which are dynamically stable (for at least 10810^8 years). We apply a GPU version of Radial velocity Using N-body Differential evolution Markov Chain Monte Carlo (RUN DMC; B. Nelson et al. 2014) to perform a Bayesian analysis of the radial velocity and transit observations. Each of the planets in this remarkable system has unique characteristics. Our investigation of high-cadence radial velocities and priors based on space-based photometry yields an updated mass estimate for planet "e" (8.09±0.268.09\pm0.26 M_\oplus), which affects its density (5.51±1.001.325.51\pm^{1.32}_{1.00} g cm3^{-3}) and inferred bulk composition. Dynamical stability dictates that the orbital plane of planet "e" must be aligned to within 60o60^o of the orbital plane of the outer planets (which we assume to be coplanar). The mutual interactions between the planets "b" and "c" may develop an apsidal lock about 180o180^o. We find 36-45% of all our model systems librate about the anti-aligned configuration with an amplitude of 51o±10o6o51^o\pm^{6^o}_{10^o}. Other cases showed short-term perturbations in the libration of ϖbϖc\varpi_b-\varpi_c, circulation, and nodding, but we find the planets are not in a 3:1 mean-motion resonance. A revised orbital period and eccentricity for planet "d" pushes it further toward the closest known Jupiter analog in the exoplanet population.Comment: 12 pages, 5 figures, 4 tables, accepted to MNRAS. Figure 2 (left) is updated from published version. Posterior samples available at http://www.personal.psu.edu/ben125/Downloads.htm

    Alexandre goes south: A novel – and – An essay, ‘The modern adventure novel’

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    When asked what sort of novel I was writing, I always said ‘a modern adventure novel’. And then I began to question myself about the meaning of these three words together, the substance and the definition of a modern adventure novel. Does such a thing exist? In my novel ‘Alexandre Goes South’, Alexandre is a thirty-year-old Parisian from a family that enjoy wealth and privilege, facts that provide a setting but play only incidental roles in the events that unfold. Alexandre goes through a series of crises, which propel the journey that launches him onto the road to manhood. The novel begins at the exact moment of suffering, after a break

    Design of a New Telescope Control System for Use in Astronomical Transient Events

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    Robotic autonomous telescopes provide highlevel control by selecting astronomical targets for observation, and they usually run under the control of a scheduler. TalonVIEW is a newly designed robotic autonomous telescope control system (TCS) for 16 inches telescope mount for use in astronomical transient events. The telescope control algorithm was implemented in PXI chassis written in GProgramming (LabVIEW) on realtime operating system(PharLab) from scratch. A new TCP/IP library was also implemented in Talon software to communicate with Pharlab in PXI chassis. Initial setup without any permanent pier and polar alignment showed that the pointing error of the telescope has been obtained as 2.22 arcminutes (132 arcseconds) in RA axis (horizontal axis of the image) and 25 arcseconds in Dec axis (vertical axis of the image), and tracking error has been observed as 4.8 arcseconds per second

    Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

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    A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results
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