1,998 research outputs found

    Pollutant emissions in common-rail diesel engines in extraurban cycle: rapeseed oils vs diesel fuel

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    The new energy strategy of EU (i.e., Directive 2009/28/EC) requires increasing the use of biofuels in transports up to at least 10% of the total fuel consumption. In the last years, the share of Diesel engines in automotive applications reached about 55% in EU market, thus trying to widen the alternatives to Diesel fuel is very important. In this framework straight vegetable oils (SVO) can represent one of the available possibilities at least in some specific applications (i.e., public transportation, hybrid or marine propulsion, etc.). SVO properties may be very different form Diesel fuel, thus operating a Diesel engine with SVO might result in some problems, especially in automotive configuration where the electronic unit acts as if it is working with Diesel fuel. This reflects in possible engine power and torque reduction, maintenance problems, and pollutant emissions during vehicles running. The latter aspect is the focus of the present paper. In this work, we used a turbocharged, four stroke, four cylinders, water cooled, commonrail multijet Diesel engine in automotive configuration to simulate the extraurban cycle according to the EU standard, comparing pollutant emissions in case of SVO and gasoil fuelling

    Internal combustion engine sensor network analysis using graph modeling

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    In recent years there has been a rapid development in technologies for smart monitoring applied to many different areas (e.g. building automation, photovoltaic systems, etc.). An intelligent monitoring system employs multiple sensors distributed within a network to extract useful information for decision-making. The management and the analysis of the raw data derived from the sensor network includes a number of specific challenges still unresolved, related to the different communication standards, the heterogeneous structure and the huge volume of data. In this paper we propose to apply a method based on complex network theory, to evaluate the performance of an Internal Combustion Engine. Data are gathered from the OBD sensor subset and from the emission analyzer. The method provides for the graph modeling of the sensor network, where the nodes are represented by the sensors and the edge are evaluated with non-linear statistical correlation functions applied to the time series pairs. The resulting functional graph is then analyzed with the topological metrics of the network, to define characteristic proprieties representing useful indicator for the maintenance and diagnosis

    Electron beam combination by RF deflectors: Tolerance and requirements

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    In the framework of the new Compact Linear Collider (CLIC) Test Facility CTF3, it is planned to perform a demonstration of the bunch frequency multiplication process on which the CLIC drive beam generation scheme is based. This process relies on the combination of electron bunch trains in isochronous rings using RF deflecting cavities. Specific requirements are imposed on both the beam characteristics and the RF amplitude and phase in the deflectors. In this paper, we study and specify these requirements in the case of the Preliminary Phase of CTF3

    On Fuzzy Corsini's Hyperoperations

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    We generalize the concept of C-hyperoperation and introduce the concept of F-C-hyperoperation. We list some basic properties of F-C-hyperoperation and the relationship between the concept of C-hyperoperation and the concept of F-C-hyperoperation. We also research F-C-hyperoperations associated with special fuzzy relations

    The CLIC Multi-Drive Beam Scheme

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    The CLIC study of an e+ / e- linear collider in the TeV energy range is based on Two-Beam Acceleration (TBA) in which the RF power needed to accelerate the beam is extracted from high intensity relativistic electron beams, the so-called drive beams. The generation, acceleration and transport of the high-intensity drive beams in an efficient and reliable way constitute a challenging task. An overview of a potentially very effective scheme is presented. It is based on the generation of trains of short bunches, accelerated sequentially in low frequency superconducting cavities in a c.w. mode, stored in an isochronous ring and combined at high energy by funnelling before injection by sectors into the drive linac for RF power production. The various systems of the complex are discussed

    Atomistic subsemirings of the lattice of subspaces of an algebra

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    Let A be an associative algebra with identity over a field k. An atomistic subsemiring R of the lattice of subspaces of A, endowed with the natural product, is a subsemiring which is a closed atomistic sublattice. When R has no zero divisors, the set of atoms of R is endowed with a multivalued product. We introduce an equivalence relation on the set of atoms such that the quotient set with the induced product is a monoid, called the condensation monoid. Under suitable hypotheses on R, we show that this monoid is a group and the class of k1_A is the set of atoms of a subalgebra of A called the focal subalgebra. This construction can be iterated to obtain higher condensation groups and focal subalgebras. We apply these results to G-algebras for G a group; in particular, we use them to define new invariants for finite-dimensional irreducible projective representations.Comment: 14 page

    Selected new developments in asbestos immunotoxicity.

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    Research over the past three decades has shown that the mammalian immune system can be altered by the occupational exposure of asbestos. Early clinical studies generally focused on systemic observations of immune alteration such as the number and function of peripheral lymphocytes and monocytes. More recently as the regulatory influence of local immunity in health and disease becomes more defined, immunologic changes occurring in the lung, the primary target organ of asbestos, have been significant areas of investigation. This review will focus on recent studies that examine the influence of asbestos on pulmonary immunity as well as the role of host immune competence in asbestos-related disease

    A New Ultra-dense Group of Obscured Emission-Line Galaxies

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    We present the discovery of an isolated compact group of galaxies that is extremely dense (median projected galaxy separation: 6.9 kpc), has a very low velocity dispersion (σ2D\sigma_{\rm 2D} = 67 km s1^{-1}), and where all observed members show emission lines and are morphologically disturbed. These properties, together with the lack of spirals and the presence of a prominent tidal tail make this group one of the most evolved compact groups.Comment: 15 pages,LaTeX, 2figures. A Postscript figure with spectra is available at ftp://astro.uibk.ac.at/pub/weinberger/ . Accepted for publication in ApJ Letter
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