912 research outputs found

    An algorithm of the wildfire classification by its acoustic emission spectrum using Wireless Sensor Networks

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    Crown fires are extremely dangerous as the speed of their distribution is dozen times higher compared to surface fires. Therefore, it is important to classify the fire type as early as possible. A method for forest fires classification exploits their computed acoustic emission spectrum compared with a set of samples of the typical fire acoustic emission spectrum stored in the database. This method implies acquisition acoustic data using Wireless Sensors Networks (WSNs) and their analysis in a central processing and a control center. The paper deals with an algorithm which can be directly implemented on a sensor network node that will allow reducing considerably the network traffic and increasing its efficiency. It is hereby suggested to use the sum of the squares ratio, with regard to amplitudes of low and high frequencies of the wildfire acoustic emission spectrum, as the indicator of a forest fire type. It is shown that the value of the crown fires indicator is several times higher than that of the surface ones. This allows classifying the fire types (crown, surface) in a short time interval and transmitting a fire type indicator code alongside with an alarm signal through the network

    Calculation of the Alpha--Particle Ground State within the Hyperspherical Harmonic Basis

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    The problem of calculating the four--nucleon bound state properties for the case of realistic two- and three-body nuclear potentials is studied using the hyperspherical harmonic (HH) approach. A careful analysis of the convergence of different classes of HH functions has been performed. A restricted basis is chosen to allow for accurate estimates of the binding energy and other properties of the 4He ground state. Results for various modern two-nucleon and two- plus three-nucleon interactions are presented. The 4He asymptotic normalization constants for separation in 2+2 and 1+3 clusters are also computed.Comment: 29 pages, 4 figures, 11 tables, revtex

    Performance of the CMS Cathode Strip Chambers with Cosmic Rays

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    The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 microns to 243 microns. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns

    Resonant Andreev reflections in superconductor-carbon-nanotube devices

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    Resonant Andreev reflection through superconductor-carbon-nanotube devices was investigated theoretically with a focus on the superconducting proximity effect. Consistent with a recent experiment, we find that for high transparency devices on-resonance, the Andreev current is characterized by a large value and a resistance dip; low-transparency off-resonance devices give the opposite result. We also give evidence that the observed low-temperature transport anomaly may be a natural result of Andreev reflection process

    Performance and Operation of the CMS Electromagnetic Calorimeter

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    The operation and general performance of the CMS electromagnetic calorimeter using cosmic-ray muons are described. These muons were recorded after the closure of the CMS detector in late 2008. The calorimeter is made of lead tungstate crystals and the overall status of the 75848 channels corresponding to the barrel and endcap detectors is reported. The stability of crucial operational parameters, such as high voltage, temperature and electronic noise, is summarised and the performance of the light monitoring system is presented

    Auto- and cross-correlation analysis of the QSOs radio wave intensity

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    © Published under licence by IOP Publishing Ltd. We discuss here the Flicker-Noise Spectroscopy approach to studying astrophysical systems, for example the radio wave intensity of quasi-stellar object (QSO) 1641+399 and BL Lacertae (BL Lac) 0215+015 in different frequency ranges. The presented method allows to parameterize the study dynamics using a short set of characteristics. The considering sources have a significant differences in manifesting the non-stationary effects, dynamical intermittency and synchronization. The radio wave intensity dynamics of the BL Lac 0215+015 is characterized by well-defined set of natural frequencies, persistent behavior with low effects of non-stationarity and high level of frequency-phase synchronization. For dynamics of the QSO 1641+399 reverse occurs including the asymmetrical structure of cross-correlator. Our findings show that using the flicker-noise spectroscopy approach to studying astrophysical objects allows to carry out the more detail analysis of their behavior and evolution

    Dynamic and spectral X-ray features of the microquasar XTE J1550-564

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    Memory function formalism is used to investigate the dynamic and spectral features (including a quantitative comparison of the decay of correlations and statistical memory) of the time discrete X-ray signals from the microquasar XTE J1550-564. The X-ray dynamics has been recorded aboard the Rossi X-Ray Timing Explorer. Temporal and event correlations are analyzed to find distinct patterns in the relaxation processes and memory effects in the equi- and nonequidistant dynamics of the X-ray flux from XTE J1550-564. The described method can be used to study a wide range of astrophysical phenomena and processes associated with event representation. © 2014 Allerton Press, Inc

    The development of electrolytes for intermediate temperature solid oxide fuel cells

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    This report describes a number of experimental studies on the solid state electrolytes for intermediate temperature solid oxide fuel cells (IT-SOFCs): Ce1-xLnxO2-δ (Ln = La, Nd, Sm, Eu, Gd, Dy, Ho, Er, Yb), some multicomponent systems Ce1-xLnx/2Ln x/2O2-δ (x = 0 - 0.20; Ln = Sm, La, Gd and L'n = Dy, Nd, Y), some systems with simultaneous doping by rare earth and alkali earth elements Ce0.8(Sm1-xMx)0.2O2-δ (M = Ca, Sr; x = 0.0 - 1.0) and Ce0.8(Sm1-x-yBayMx)0.2O2-δ (M = Ca, Sr; x = 0, 0.15, 0.20; y = 0.05, 0.1). Two important aspects are emphasized: the effect of different dopants' ionic radius and concentration on the electrical properties of CeO2 based solid solutions and the influence of the method of preparation on the structural properties of ceria ceramics and the electrochemical performance of single SOFCs on their base. To describe the electrolytic properties of solid electrolytes the notation of the electrolytic domain boundary (EDB) - the critical oxygen partial pressure P*O2 at which the values of the electronic and ionic components of conductivity are equal, were calculated and presented. The interpretation of these data will lead to a better understanding of, subsequent improvements to and ultimately, the commercialization of IT-SOFCs in Russia. © 2014 WIT Press.International Journal of Safety and Security Engineering;International Journal of Sustainable Development and Planning;WIT Transactions on Ecology and the Environmen
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