37,990 research outputs found

    Measurements of jet quenching with semi-inclusive charged jet distributions in Au+AuAu+Au collisions at sNN\sqrt{s_{NN}}=200 GeV

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    We report measurements of jet quenching in Au+AuAu+Au collisions at sNN\sqrt{s_{NN}}=200 GeV, based on the semi-inclusive distribution of reconstructed charged particle jets recoiling from a high pTp_T hadron trigger. Jets are reconstructed with the anti-kT_T algorithm (RR=0.2 to 0.5), with low IR-cutoff of track constituents (pT>0.2p_{T}>0.2 GeV/c). Uncorrelated background is corrected using a novel mixed-event technique, with no fragmentation bias imposed by the correction procedure on the accepted recoil jet population. Corrected recoil jet distributions, reported in the range 0<pT,jetch<300<p_{T,jet}^{ch}<30 GeV/c, are used to measure jet yield suppression, jet energy loss, and intra-jet broadening. The first search for QCD Moli\`ere scattering of jets in hot QCD matter at RHIC is reported.Comment: Proceedings of the Quark Matter 2015 conferenc

    Mach 4 and Mach 8 axisymmetric nozzles for a shock tunnel

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    The performance of two axisymmetric nozzles which were designed to produce uniform, parallel flow with nominal Mach numbers of 4 and 8 is examined. A free-piston-driven shock tube was used to supply the nozzle with high-temperature, high-pressure test gas. The inviscid design procedure treated the nozzle expansion in two stages. Close to the nozzle throat, the nozzle wall was specified as conical and the gas flow was treated as a quasi-one-dimensional chemically-reacting flow. At the end of the conical expansion, the gas was assumed to be calorically perfect, and a contoured wall was designed (using method of characteristics) to convert the source flow into a uniform and parallel flow at the end of the nozzle. Performance was assessed by measuring Pitot pressures across the exit plane of the nozzles and, over the range of operating conditions examined, the nozzles produced satisfactory test flows. However, there were flow disturbances in the Mach 8 nozzle flow that persisted for significant times after flow initiation

    Simulation of transient flow in a shock tunnel and a high Mach number nozzle

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    A finite volume Navier-Stokes code was used to simulate the shock reflection and nozzle starting processes in an axisymmetric shock tube and a high Mach number nozzle. The simulated nozzle starting processes were found to match the classical quasi-1-D theory and some features of the experimental measurements. The shock reflection simulation illustrated a new mechanism for the driver gas contamination of the stagnated test gas

    Synchronisation of financial crises

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    This paper develops concordance indices for studying the simultaneous occurrence of financial crises. The indices are designed to cope with these typically low incidence events. This leads us to confine attention to non-tranquil periods to develop a bivariate index and its multivariate analog for potentially serially correlated categorical data. An application to the Bordo et al. (2001) data set reveals the extent of concordance in banking and currency crises across countries. The internationalisation of financial crises in the 20th century is shown to have increased for currency crises and decreased for banking crises

    MBCNS2 Example Book

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    MBCNS2 is a small collection of programs for the simulation of transient two-dimensional (or axisymmetric) flows. It is part of the larger collection of compressible flow simulation codes found at http://www.mech.uq.edu.au/cfcfd/. This manual is a collection of example simulations: scripts, results and commentary. It may be convenient for new users of the code to identify an example close to the situation that they wish to model and then adapt the scripts for that example

    A tutorial guide to programming PIC18 microcontrollers with FlashForth

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    Modern microcontrollers provide an amazingly diverse selection of hardware peripher-als, all within a single chip. One needs to provide a small amount of supporting hardware to power the chip and connect its peripheral devices to the signals of interest and, when powered up, these devices need to be configured and monitored by a suitable firmware program. These notes focus on programming a PIC18F2520 microcontroller in a simple hardware environment and provide a number of example programs (in the Forth language) to illustrate the use of some of the MCU’s peripheral devices

    A tutorial guide to programming PIC18, PIC24 and ATmega microcontrollers with FlashForth

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    A programmable pulsed-light source using a light-emitting diode

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    Why didn't the Global Financial Crisis hit Latin America?

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    Latin America has a rich history of financial crises. However, it was relatively unharmed by the 2007-2009 Global Financial Crisis (GFC). This paper investigates why, and in particular the role of commodity prices and its institutional framework - in line with the fourth generation financial crisis model. We set up Early Warning Systems (EWS) for Argentina, Brazil and Mexico. These consist of an ordered logit model for currency crises for the period 1990-2007 with a dynamic factor model to deal with the large number of explanatory variables. We present forecasts for the period 2008-2009. We find that international indicators play an important role in explaining currency crises in Mexico, while banking indicators and commodities explain the currency crisis in Argentina and Brazil. Furthermore, debt and domestic economy indicators are relevant for Argentina and Mexico. Finally, we observe that currency crises in all three countries are related to institutional indicators. For none of the countries the Early Warning System would have issued an early warning for the GFC.Financial crises, Early Warning Systems, Latin America, dynamic factor models, ordered logit model,
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