1,125 research outputs found

    Modelling effects of an asphalt road at a dike crest on dike cover erosion onset during wave overtopping

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    Structures integrated in a grass-covered dike may increase erosion development. Currently, safety assessment methods for flood defences are only applicable for a conventional grass-covered dike and the effects of structures on dike cover erosion are poorly understood. Since many dikes have a road on top, it is important to study the effect of such a road structure on erosion onset during wave overtopping. To investigate this effect, a coupled hydrodynamic–eroison model was developed. The erosion onset caused by overtopping waves was predicted by combining the time-varying bed shear stresses from the hydrodynamic model with a depth-dependent erosion model. The results show that roads on top of a dike increase the erosion of the neighbouring grass cover. This increase in erosion may have a negative impact on dike stability. Therefore, we recommend considering effects of constructions on top of dike profiles during safety assessments. Explicitly, consideration of the roughness transitions in the safety assessments of dikes is recommende

    Electron neutrino tagging through tertiary lepton detection

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    We discuss an experimental technique aimed at tagging electron neutrinos in multi-GeV artificial sources on an event-by-event basis. It exploits in a novel manner calorimetric and tracking technologies developed in the framework of the LHC experiments and of rare kaon decay searches. The setup is suited for slow-extraction, moderate power beams and it is based on an instrumented decay tunnel equipped with tagging units that intercept secondary and tertiary leptons from the bulk of undecayed \pi^+ and protons. We show that the taggers are able to reduce the \nue contamination originating from K_e3 decays by about one order of magnitude. Only a limited suppression (~60%) is achieved for \nue produced by the decay-in-flight of muons; for low beam powers, similar performance as for K_e3 can be reached supplementing the tagging system with an instrumented beam dump.Comment: 19 pages, 7 figures; minor changes, version to appear in EPJ

    Recession, employment and self-rated health: a study on the gender gap

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    Objectives: Employment status and economic recession have been associated with negative effects on self-rated health, and this effect differs by gender. We analysed the effects of the Spanish economic recession in terms of self-rated health, its differential effect among genders and its influence on gender gap. Study design: Repeated cross-sectional study using Spanish health surveys (2001–2014). Methods: Logistic regression models were conducted to explore the association between self-rated health and employment status and its evolution over time and gender. To test the impact of the economic recession, pooled data regression models were conducted. Results: In this study, we considered 104,577 subjects. During the last 15 years, women have entered the labour market, leading to wide changes in the Spanish traditional family roles. Instead of an increasing proportion of women workers, gender employment differences persist. Therefore, in 2014, the prevalence of workers was 55.77% in men, whereas in women, it was 44.01%. Self-rated health trends during the economic recession differ by gender, with women improving slightly their self-rated health from a low self-rated health prevalence of 38.76% in 2001 to 33.78% in 2014. On the contrary, men seem more vulnerable to employment circumstances, which have led to substantial reduction in the gender gap. Conclusions: Although a gender gap persists, the change in socio-economic roles seems to increase women's self-rated health, reducing this gap. It is important to promote women's labour market inclusion, even in economic recession periods

    Multiple bound states in scissor-shaped waveguides

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    We study bound states of the two-dimensional Helmholtz equations with Dirichlet boundary conditions in an open geometry given by two straight leads of the same width which cross at an angle Ξ\theta. Such a four-terminal junction with a tunable Ξ\theta can realized experimentally if a right-angle structure is filled by a ferrite. It is known that for Ξ=90o\theta=90^o there is one proper bound state and one eigenvalue embedded in the continuum. We show that the number of eigenvalues becomes larger with increasing asymmetry and the bound-state energies are increasing as functions of Ξ\theta in the interval (0,90o)(0,90^o). Moreover, states which are sufficiently strongly bent exist in pairs with a small energy difference and opposite parities. Finally, we discuss how with increasing Ξ\theta the bound states transform into the quasi-bound states with a complex wave vector.Comment: 6 pages, 6 figure

    Experimental determination of the effective strong coupling constant

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    We present a first attempt to experimentally extract an effective strong coupling constant that we define to be a low Q2 extension of a previous definition by S. Brodsky et al. following an initial work of G. Grunberg. Using Jefferson Lab data and sum rules, we establish its Q2-behavior over the complete Q2-range. The result is compared to effective coupling constants inferred from different processes and to calculations based on Schwinger-Dyson equations, hadron spectroscopy or lattice QCD. Although the connection between the experimentally extracted effective coupling constants and the calculations is not established it is interesting to note that their behaviors are similar.Comment: Published in Physics Letters B 650 4 24

    Structure of a complex carbonate aquifer by magnetic, gravity and TDEM prospecting in the Jaén area, Southern Spain

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    Knowledge of aquifer geometry is essential for efficient and sustainable groundwater management, particularly in carbonate aquifers due to uncertainties inherent to karstic systems. The geological structure and hydrogeological continuity of Los Chotos-Sazadilla-Los Nacimientos and La Serreta-Gante-Cabeza Montosa carbonate aquifers (JaĂ©n; SE Spain) have been established through structural measurements, geophysical prospecting –magnetic, gravity and time-domain electromagnetics (TDEM)– and the study of piezometric levels. Yet the scarce hydrogeological data, the complexity of the tectonic structure and the presence of Plio-Quaternary rocks covering the highly permeable carbonate rocks make it difficult to establish a robust conceptual hydrogeological model of the aquifer. This study focuses on an area where hydrogeological disconnection between the two aquifers was traditionally assumed, given the diapiric emplacement of low permeable rocks between them. The new geophysical data demonstrate connection between aquifers that implies greater groundwater reserves than previously supposed. This field example supports the suitability of the combined use of electromagnetic methods with gravity and magnetic research that have been poorly combined up to recent times for hydrogeological studies
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