18 research outputs found

    Weighted Automata and Logics for Infinite Nested Words

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    Nested words introduced by Alur and Madhusudan are used to capture structures with both linear and hierarchical order, e.g. XML documents, without losing valuable closure properties. Furthermore, Alur and Madhusudan introduced automata and equivalent logics for both finite and infinite nested words, thus extending B\"uchi's theorem to nested words. Recently, average and discounted computations of weights in quantitative systems found much interest. Here, we will introduce and investigate weighted automata models and weighted MSO logics for infinite nested words. As weight structures we consider valuation monoids which incorporate average and discounted computations of weights as well as the classical semirings. We show that under suitable assumptions, two resp. three fragments of our weighted logics can be transformed into each other. Moreover, we show that the logic fragments have the same expressive power as weighted nested word automata.Comment: LATA 2014, 12 page

    Zitterbewegung in External Magnetic Field: Classic versus Quantum Approach

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    We investigate variations of the Zitterbewegung frequency of electron due to an external static and uniform magnetic field employing the expectation value quantum approach, and compare our results with the classical model of spinning particles. We demonstrate that these two so far compatible approaches are not in agreement in the presence of an external uniform static magnetic field, in which the classical approach breaks the usual symmetry of free particles and antiparticles states, i.e. it leads to CP violation. Hence, regarding the Zitterbewegung frequency of electron, the classical approach in the presence of an external magnetic field is unlikely to correctly describe the spin of electron, while the quantum approach does, as expected. We also show that the results obtained via the expectation value are in close agreement with the quantum approach of the Heisenberg picture derived in the literature. However, the method we use is capable of being compared with the classical approach regarding the spin aspects. The classical interpretation of spin produced by the altered Zitterbewegung frequency, in the presence of an external magnetic field, are discussed.Comment: 16 pages, no figure

    Biological response of an in vitro human 3D lung cell model exposed to brake wear debris varies based on brake pad formulation

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    Wear particles from automotive friction brake pads of various sizes, morphology, and chemical composition are significant contributors towards particulate matter. Knowledge concerning the potential adverse effects following inhalation exposure to brake wear debris is limited. Our aim was, therefore, to generate brake wear particles released from commercial low-metallic and non-asbestos organic automotive brake pads used in mid-size passenger cars by a full-scale brake dynamometer with an environmental chamber simulating urban driving and to deduce their potential hazard in vitro. The collected fractions were analysed using scanning electron microscopy via energy-dispersive X-ray spectroscopy (SEM-EDS) and Raman microspectroscopy. The biological impact of the samples was investigated using a human 3D multicellular model consisting of human epithelial cells (A549) and human primary immune cells (macrophages and dendritic cells) mimicking the human epithelial tissue barrier. The viability, morphology, oxidative stress, and (pro-)inflammatory response of the cells were assessed following 24 h exposure to similar to 12, similar to 24, and similar to 48 A mu g/cm(2) of non-airborne samples and to similar to 3.7 A mu g/cm(2) of different brake wear size fractions (2-4, 1-2, and 0.25-1 A mu m) applying a pseudo-air-liquid interface approach. Brake wear debris with low-metallic formula does not induce any adverse biological effects to the in vitro lung multicellular model. Brake wear particles from non-asbestos organic formulated pads, however, induced increased (pro-)inflammatory mediator release from the same in vitro system. The latter finding can be attributed to the different particle compositions, specifically the presence of anatase.Web of Science9272351233

    Nanoparticle emissions from 11 non-vehicle exhaust sources – A review

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    Lowbrasys brake wear cycle - 3h LACT

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    This dataset is brake wear cycle that was used as a reference cycle in the EU co-funded project LOWBRASYS which aims at particle reduction from automotive brakes. One task within the LOWBRASYS project was to define a real-drive braking schedule. This cycle is a short version of an existing brake procedure (Los Angeles City Traffic (LACT)) that was generated from actual on-road driving data and addresses typical urban, extra-urban and highway drive conditions. It is noteworthy that another real-world cycle has been developed [Mathissen et al. 2018]. The main difference between the two newly developed cycles is that the present LOWBRASYS cycle is based on a limited dataset from a specific region, while the other cycle is based on the WLTP database, which covers much more use-case and driving conditions. The PMP IWG has decided to use the present cycle as a backup cycle for future brake wear emissions evaluation

    WLTP-based Real-World Brake Wear Cycle

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    WLTP based brake wear cycle including: Second-by-second data of the speed/time trace. Location and duration of trip breaks. Cycle edges: Since the cycle is rectified there are only certain points needed to reproduce the cycle. These data points that build up the speed/time trace are listed here. Stop overview: Each of the 303 stops is listed with indiviudal stop nr., start time within the cycle (without any trip breaks), initial and final velocity as well as brake duration and deceleration
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