13,614 research outputs found

    Testing Observational Techniques with 3D MHD Jets in Clusters

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    Observations of X-ray cavities formed by powerful jets from AGN in galaxy cluster cores are commonly used to estimate the mechanical luminosity of these sources. We test the reliability of observationally measuring this power with synthetic X-ray observations of 3-D MHD simulations of jets in a galaxy cluster environment. We address the role that factors such as jet intermittency and orientation of the jets on the sky have on the reliability of observational measurements of cavity enthalpy and age. An estimate of the errors in these quantities can be made by directly comparing ``observationally'' derived values with values from the simulations. In our tests, cavity enthalpy, age and mechanical luminosity derived from observations are within a factor of two of the simulation values.Comment: 4 pages, 3 figures; to appear in proceedings of The Monster's Fiery Breath: Feedback in Galaxies, Groups, and Clusters (AIP conference series

    Baryon and antibaryon production in hadron-hadron and hadron-nucleus interactions

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    Cascade baryon and anti-baryon yields have been measured in p+p and p+A collisions. After extraction of the projectile component in p+A interactions close similarities with A+A collisions concerning the nuclear enhancement factors are observed. In addition the importance of effects related to projectile isospin and to net baryon stopping is pointed out.Comment: 4 pages, 5 figures, Presented at Quark Matter 2002, Nantes, Franc

    Resonance Production in STAR

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    The recent results from resonance production in central Au+Au and p+p collisions at sNN=\sqrt{s_{\rm NN}} = 200 GeV from the STAR experiment at RHIC are presented and discussed.Comment: 7 pages, proceedings 19th Winter Workshop on Nuclear Dynamics, Breckenridge, Colorado, USA, February 8-15, 200

    A feasibility study on using inkjet technology, micropumps, and MEMs as fuel injectors for bipropellant rocket engines

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    Control over drop size distributions, injection rates, and geometrical distribution of fuel and oxidizer sprays in bi-propellant rocket engines has the potential to produce more efficient, more stable, less polluting rocket engines. This control also offers the potential of an engine that can be throttled, working efficiently over a wide range of output thrusts. Inkjet printing technologies, MEMS fuel atomizers, and piezoelectric injectors similar in concept to those used in diesel engines are considered for their potential to yield a new, more active injection scheme for a rocket engine. Inkjets are found to be unable to pump at sufficient pressures, and have possibly dangerous failure modes. Active injection is found to be feasible if high pressure drop along the injector plate are used. A conceptual design is presented and its basic behavior assessed

    Investigation into the hardbean phenomenon in phaseolus vulgaris L.

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    The textural deterioration of dry beans during storage was investigated. The primary symptoms of this hardbean phenomenon were found to be reduced viability, reduced water uptake and reduced cooking rate. It was found that the basic cause of the beans failing to cook - or soften - was the failure of the cotyledon cells to separate during the cooking process. From these initial observations it was hypothesised that reduced cell separation rate was due to either reduced turgor pressure due to reduced water uptake, or reduced pectin solubility, or both. Techniques used included light microscopy, transmission and scanning electron microscopy, thin-layer chromatography and spectrophotometry and it was found that reduced cell separation rate was due to a combination of both reduced water uptake and reduced pectin solubility. By inducing the hardbean symptoms artificially their relevance to textural deterioration were determined. The significant events within the beans during storage were found to be phytin breakdown, membrane deterioration, cation leakage, pectin demethylation and pectin calcification. By running a storage trial and thus allowing hardness to develop within the beans the sequence of events was elucidated

    Selected results on Strong and Coulomb-induced correlations from the STAR experiment

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    Using recent high-statistics STAR data from Au+Au and Cu+Cu collisions at full RHIC energy I discuss strong and Coulomb-induced final state interaction effects on identical (π−π\pi-\pi) and non-identical (π−Ξ\pi-\Xi) particle correlations. Analysis of π−Ξ\pi-\Xi correlations reveals the strong and Coulomb-induced FSI effects allowing for the first time to estimate space extension of π\pi and Ξ\Xi sources and average shift between them. Source imaging technique providing clean separation of these effects from effects due to the source function itself is applied to one-dimensional relative momentum correlation function of identical pions. For low momentum pions and/or non-central collisions large departure from a single-Gaussian shape is observed

    Centrality Dependence of Azimuthal Anisotropy of Strange Hadrons in 200 GeV Au+Au Collisions

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    Measurements of azimuthal anisotropy for strange and multi-strange hadrons are presented for the first time in their centrality dependence. The high statistics results of v2(pT) allow for a more detailed comparison to hydrodynamical model calculations. Number-of-constituent-quark scaling was tested for different centrality classes separately. Higher order anisotropies like v4(pT) are measured for multi-strange hadrons. While we observe agreement between measured data and models a deeper understanding and refinement of the models seem to be necessary in order to fully understand the details of the data.Comment: 4 pages, 2 figures; Strange Quark Matter 2006 conference proceedings, to appear in J. Phys.

    How well does NLO pQCD describe strangeness in p+pp+p collisions at s\sqrt{s}= 200 GeV in STAR?

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    We present measurements of the transverse momentum spectra for KS0\mathrm{K^{0}_{S}}, Λ\Lambda, Ξ\Xi and their antiparticles in p+p collisions at s=200GeV\sqrt{s}=200 GeV. The extracted mid-rapidity yields and are in agreement with previous p+pˉp+\bar{p} experiments while they have smaller statistical errors. We compare the measured spectra for KS0\mathrm{K^{0}_{S}} and Λ\Lambda to the latest available calculations from NLO pQCD and see good agreement for the KS0\mathrm{K^{0}_{S}} above 1.5 GeV/c.Comment: conference proceedings, Strangeness in Quark Matter 2004, 5 pages, submitted to Journal Physics G, final version submitted to journal incl. modifications requested by edito

    Editorial

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    This special issue of MSOR Connections is based on contributions to a workshop, ‘Programming in the undergraduate mathematics curriculum’, which took place at Middlesex University on 27th June 2019, and other submissions received on the same theme
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