1,056 research outputs found

    Influence Of Formation Processes On Oblique Detonation Wave Stabilization

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    In this article we report steady, two-dimensional, inviscid solutions for the near field and far field of a supersonic reactive flow over a variable-double-ramp geometry. The incident shock wave compresses and heats the reactants that will combust after flowing some induction length. Upon reaction, a detonation wave forms and intersects the leading wave at some distance from the ramp surface. In this article, reaction-polar diagrams are developed, and the detonation branch solutions are used to investigate the wave interaction processes that may lead to a steady three-wave structure. By considering this formation process new oblique detonation wave stabilization criteria based on the freestream conditions and ramp geometry are provided

    The influences of nursing transformational leadership style on the quality of nurses’ working lives in Taiwan: a cross-sectional quantitative study

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    - Background: Taiwan’s NHI system is one of the most successful health care models for countries around the globe. However, little research has demonstrated the mental health issues associated with nursing transformational leadership style under the NHI system, especially in the quality of nurses’ working lives in Taiwan. It is important to know the relationship between transformational leadership style and the mental health of nurses, organisational commitment and job satisfaction. The research aimed to understand the influences of nursing transformational leadership style on the quality of nurses’ working lives in Taiwan. The research hypothesis was that transformational leadership styles would have positive influence on the quality of nurses’ working lives. - Methods: This was a cross-sectional quantitative study. Nurses from each type of hospital ownership (private, public and religious) were recruited. Participation was voluntary and signed informed consent was obtained. The inclusion criteria were nurses with at least one year’s work experience in the hospitals. Self-administrated questionnaires were used. A total of 807 participants were contacted and 651 questionnaires were fully completed (response rate 80.7 %). A theory driven model was used to test the research hypotheses using structural equation modelling performed with AMOS 16.0. - Results: Transformational leadership contributes significantly to supervisor support. Workplace support, particularly from the supervisor, is an important mediator variable that explains the relationship between transformational leadership and job satisfaction. Organisational commitment was the strongest factor relevant to the general health well-being in Taiwanese nurses than job satisfaction. The hypothesized positive relationships between transformational leadership and all variables were supported by the data. - Conclusions: Our findings have important consequences for organisational health. Our model demonstrates a complete picture of the work relationships on the quality of nurses’ working lives. The results provided information about the subordinates’ perceptions of transformational nursing leadership styles and mental health outcomes in different hospital settings, as well as identified organisational factors that could improve the quality of nurses’ working lives

    Measurement of exclusive pion pair production in proton–proton collisions at √s=7 TeV with the ATLAS detector

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    The exclusive production of pion pairs in the process pp→ ppπ+π- has been measured at s=7TeV with the ATLAS detector at the LHC, using 80μb-1 of low-luminosity data. The pion pairs were detected in the ATLAS central detector while outgoing protons were measured in the forward ATLAS ALFA detector system. This represents the first use of proton tagging to measure an exclusive hadronic final state at the LHC. A cross-section measurement is performed in two kinematic regions defined by the proton momenta, the pion rapidities and transverse momenta, and the pion–pion invariant mass. Cross-section values of 4.8±1.0(stat)-0.2+0.3(syst)μb and 9±6(stat)-2+2(syst)μb are obtained in the two regions; they are compared with theoretical models and provide a demonstration of the feasibility of measurements of this type

    Measurement of the polarisation of W bosons produced in top-quark decays using dilepton events at root s=13 TeV with the ATLAS experiment

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    A measurement of the polarisation of WW bosons produced in top-quark decays is presented, using proton-proton collision data at a centre-of-mass energy of s=13\sqrt{s} = 13 TeV. The data were collected by the ATLAS detector at the Large Hadron Collider and correspond to an integrated luminosity of 139 fb1^{-1}. The measurement is performed selecting ttˉt\bar{t} events decaying into final states with two charged leptons (electrons or muons) and at least two bb-tagged jets. The polarisation is extracted from the differential cross-section distribution of the cosθ\cos{\theta^{*}} variable, where θ\theta^{*} is the angle between the momentum direction of the charged lepton from the WW boson decay and the reversed momentum direction of the bb-quark from the top-quark decay, both calculated in the WW boson rest frame. Parton-level results, corrected for the detector acceptance and resolution, are presented for the cosθ\cos{\theta^{*}} angle. The measured fractions of longitudinal, left- and right-handed polarisation states are found to be f0=0.684±0.005(stat.)±0.014(syst.)f_{0} = 0.684 \pm 0.005\,\mathrm{(stat.)} \pm 0.014\,\mathrm{(syst.)}, fL=0.318±0.003(stat.)±0.008(syst.)f_{\mathrm{L}} = 0.318 \pm 0.003\,\mathrm{(stat.)} \pm 0.008\,\mathrm{(syst.)} and fR=0.002±0.002(stat.)±0.014(syst.)f_{\mathrm{R}} = -0.002 \pm 0.002\,\mathrm{(stat.)} \pm 0.014\,\mathrm{(syst.)}, in agreement with the Standard Model prediction

    Combination of searches for heavy spin-1 resonances using 139 fb−1 of proton-proton collision data at s = 13 TeV with the ATLAS detector

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    A combination of searches for new heavy spin-1 resonances decaying into different pairings of W, Z, or Higgs bosons, as well as directly into leptons or quarks, is presented. The data sample used corresponds to 139 fb−1 of proton-proton collisions at = 13 TeV collected during 2015–2018 with the ATLAS detector at the CERN Large Hadron Collider. Analyses selecting quark pairs (qq, bb, , and tb) or third-generation leptons (τν and ττ) are included in this kind of combination for the first time. A simplified model predicting a spin-1 heavy vector-boson triplet is used. Cross-section limits are set at the 95% confidence level and are compared with predictions for the benchmark model. These limits are also expressed in terms of constraints on couplings of the heavy vector-boson triplet to quarks, leptons, and the Higgs boson. The complementarity of the various analyses increases the sensitivity to new physics, and the resulting constraints are stronger than those from any individual analysis considered. The data exclude a heavy vector-boson triplet with mass below 5.8 TeV in a weakly coupled scenario, below 4.4 TeV in a strongly coupled scenario, and up to 1.5 TeV in the case of production via vector-boson fusion
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