120 research outputs found

    Fatigue Damage Estimation in Existing Railway Steel Bridges by Detailed Loading History Analysis

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    Fatigue life estimation of metal historical bridges is a key issue for managing cost-effective decisions regarding rehabilitation or replacement of existing infrastructure. Because of increasing service loads and speeds, this type of assessment method is becoming relevant. Hence there is a need to estimate how long these structures could remain in service. In this paper a method to estimate fatigue damage in existing steel railway bridges by detailed loading history analysis is presented. The procedure is based on the assumption that failure probability is a function of the number of predicted future trains and the probability of failure is related to the probability of reaching the critical crack length

    IC-Service: A Service-Oriented Approach to the Development of Recommendation Systems

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    Recommendation systems have proven to be useful in various application domains. However, current solutions are usually ad-hoc systems which are tightly-coupled with the application domain. We present the IC-Service, a recommendation service that can be included in any system in a loosely coupled way. The implementation follows the principles of service oriented computing and provides a solution to various problems arising in recommendation systems, e.g. to the problem of meta-recommendation systems development. Moreover, when properly configured, the IC-Service can be used by different applications (clients), and several independent instances of the IC-Service can collaborate to produce better recommendations. Service architecture and communication protocols are presented. The paper describes also ongoing work and applications based on the IC-Service

    fatigue behaviour of steel bridge joints strenghtened with frp laminates

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    One of the most relevant concerns about steel and metal bridges stands on the repair and rehabilitation of existing structures. In fact, the remaining service life of steel bridges is limited by fatigue damage and in order to ensure the safety of these bridges it is often necessary to inspect the structure in order to discover the presence of fatigue cracks. New reinforcement techniques are needed, in order to prevent fatigue cracking and to increase bridge safety at the same time. According to the contemporary knowledge on the matter, two alternatives of rehabilitation are given: the traditional interventions and the use of carbon fibre composites. In this paper, in order to explain the appropriate use of these techniques, the most common knowledge on the matter are presented and explained, focusing in particular on the real scale testing results coming from the last decades research applications related to steel bridge engineering. This study should in this way be useful for future research applications and for bridge engineering real case rehabilitations

    The Interaction of Relativization and Noun Incorporation in Southern Hokkaidō Ainu

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    This paper focuses on relativization in Southern Hokkaidō Ainu. Specifically, evidential expressions constitute the scope of this study since within this semantic domain a morphosyntactic layout reminiscent of internally-headed relative clauses (IHRCs) is found. Moreover, the structure of some evidential expressions suggests that what gives rise to an IHRC in those instances is classificatory noun incorporation (CNI). Following from past studies on Ainu, where IHRCs and CNI are never discussed, and with reference to cross-linguistic approaches to relativization and incorporation, this study addresses the interaction of these two processes in Southern Hokkaidō Ainu and suggests their reconsideration

    Clinical features and outcomes of elderly hospitalised patients with chronic obstructive pulmonary disease, heart failure or both

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    Background and objective: Chronic obstructive pulmonary disease (COPD) and heart failure (HF) mutually increase the risk of being present in the same patient, especially if older. Whether or not this coexistence may be associated with a worse prognosis is debated. Therefore, employing data derived from the REPOSI register, we evaluated the clinical features and outcomes in a population of elderly patients admitted to internal medicine wards and having COPD, HF or COPD + HF. Methods: We measured socio-demographic and anthropometric characteristics, severity and prevalence of comorbidities, clinical and laboratory features during hospitalization, mood disorders, functional independence, drug prescriptions and discharge destination. The primary study outcome was the risk of death. Results: We considered 2,343 elderly hospitalized patients (median age 81 years), of whom 1,154 (49%) had COPD, 813 (35%) HF, and 376 (16%) COPD + HF. Patients with COPD + HF had different characteristics than those with COPD or HF, such as a higher prevalence of previous hospitalizations, comorbidities (especially chronic kidney disease), higher respiratory rate at admission and number of prescribed drugs. Patients with COPD + HF (hazard ratio HR 1.74, 95% confidence intervals CI 1.16-2.61) and patients with dementia (HR 1.75, 95% CI 1.06-2.90) had a higher risk of death at one year. The Kaplan-Meier curves showed a higher mortality risk in the group of patients with COPD + HF for all causes (p = 0.010), respiratory causes (p = 0.006), cardiovascular causes (p = 0.046) and respiratory plus cardiovascular causes (p = 0.009). Conclusion: In this real-life cohort of hospitalized elderly patients, the coexistence of COPD and HF significantly worsened prognosis at one year. This finding may help to better define the care needs of this population

    Measurement of ϒ production in pp collisions at √s = 2.76 TeV

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    The production of ϒ(1S), ϒ(2S) and ϒ(3S) mesons decaying into the dimuon final state is studied with the LHCb detector using a data sample corresponding to an integrated luminosity of 3.3 pb−1 collected in proton–proton collisions at a centre-of-mass energy of √s = 2.76 TeV. The differential production cross-sections times dimuon branching fractions are measured as functions of the ϒ transverse momentum and rapidity, over the ranges pT < 15 GeV/c and 2.0 < y < 4.5. The total cross-sections in this kinematic region, assuming unpolarised production, are measured to be σ (pp → ϒ(1S)X) × B ϒ(1S)→μ+μ− = 1.111 ± 0.043 ± 0.044 nb, σ (pp → ϒ(2S)X) × B ϒ(2S)→μ+μ− = 0.264 ± 0.023 ± 0.011 nb, σ (pp → ϒ(3S)X) × B ϒ(3S)→μ+μ− = 0.159 ± 0.020 ± 0.007 nb, where the first uncertainty is statistical and the second systematic

    Study of the doubly charmed tetraquark T+cc

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    Quantum chromodynamics, the theory of the strong force, describes interactions of coloured quarks and gluons and the formation of hadronic matter. Conventional hadronic matter consists of baryons and mesons made of three quarks and quark-antiquark pairs, respectively. Particles with an alternative quark content are known as exotic states. Here a study is reported of an exotic narrow state in the D0D0π+ mass spectrum just below the D*+D0 mass threshold produced in proton-proton collisions collected with the LHCb detector at the Large Hadron Collider. The state is consistent with the ground isoscalar T+cc tetraquark with a quark content of ccu⎯⎯⎯d⎯⎯⎯ and spin-parity quantum numbers JP = 1+. Study of the DD mass spectra disfavours interpretation of the resonance as the isovector state. The decay structure via intermediate off-shell D*+ mesons is consistent with the observed D0π+ mass distribution. To analyse the mass of the resonance and its coupling to the D*D system, a dedicated model is developed under the assumption of an isoscalar axial-vector T+cc state decaying to the D*D channel. Using this model, resonance parameters including the pole position, scattering length, effective range and compositeness are determined to reveal important information about the nature of the T+cc state. In addition, an unexpected dependence of the production rate on track multiplicity is observed

    Structural Analysis of the Cantilever Construction Process in Cable-Stayed Bridges

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    This work deals with the analysis of cable-stayed bridges at different erection stages during construction, assuming the full or the partial cantilever method and performing multiple finite element computational procedure. The forward process and the backward process analysis are investigated and compared: the former is performed by following the sequence of erection stages in bridge construction and the latter is carried out in the reverse direction of erection procedures. The required pretension in cable-stays and the corresponding structural configurations of the bridge at different erection stages have been examined and compared in details, also by comparing either the linear computation procedure or the nonlinear computation procedure. Numerical, analytical and construction process results are presented, compared and commented upon
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