2,844 research outputs found

    A carbonation and chloride induced corrosion model for hot-dip galvanised reinforcement bar material in concrete

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    This paper focuses on methodological issues relevant to corrosion risk prediction models. A model was developed for the prediction of corrosion rates associated with hot-dip galvanised reinforcement bar material in concrete exposed to carbonation and chlorides in outdoor environment. One-year follow-up experiments, over five years, were conducted at various carbonation depths and chloride contents. The observed dependence of corrosion rate on the depth of carbonation and chloride content is complex indicating that the interaction between the carbonation and chloride influencing the corrosion. A non-linear corrosion model was proposed with statistical analysis to model the relationship between the corrosion rate and the test parameters. The main methodological contributions are (i) the proposed modeling approach able to take into account the uncertain measurement errors including unobserved systematic and random heterogeneity over different measured specimens and correlation for the same specimen across different measuring times, which best suits the measurement data; (ii) the developed model in which an interaction parameter is introduced especially to account for the contribution and the degree of the unobserved carbonation-chloride interaction. The proposed model offers greater flexibility for the modelling of measurement data than traditional models

    Statistical investigation of climate change effects on the utilization of the sediment heat energy

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    Suvilahti, a suburb of the city of Vaasa in western Finland, was the first area to use seabed sediment heat as the main source of heating for a high number of houses. Moreover, in the same area, a unique land uplift effect is ongoing. The aim of this paper is to solve the challenges and find opportunities caused by global warming by utilizing seabed sediment energy as a renewable heat source. Measurement data of water and air temperature were analyzed, and correlations were established for the sediment temperature data using Statistical Analysis System (SAS) Enterprise Guide 7.1. software. The analysis and provisional forecast based on the autoregression integrated moving average (ARIMA) model revealed that air and water temperatures show incremental increases through time, and that sediment temperature has positive correlations with water temperature with a 2-month lag. Therefore, sediment heat energy is also expected to increase in the future. Factor analysis validations show that the data have a normal cluster and no particular outliers. This study concludes that sediment heat energy can be considered in prominent renewable production, transforming climate change into a useful solution, at least in summertime

    Lambda and Anti-Lambda Hypernuclei in Relativistic Mean-field Theory

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    Several aspects about Λ\Lambda-hypernuclei in the relativistic mean field theory, including the effective Λ\Lambda-nucleon coupling strengths based on the successful effective nucleon-nucleon interaction PK1, hypernuclear magnetic moment and Λˉ\bar\Lambda-hypernuclei, have been presented. The effect of tensor coupling in Λ\Lambda-hypernuclei and the impurity effect of Λˉ\bar\Lambda to nuclear structure have been discussed in detail.Comment: 8 pages, 2 figures, Proceedings of the Sendai International Symposium "Strangeness in Nuclear and Hadronic Systems SENDAI08

    Kondo correlation and spin-flip scattering in spin-dependent transport through a quantum dot coupled to ferromagnetic leads

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    We investigate the linear and nonlinear dc transport through an interacting quantum dot connected to two ferromagnetic electrodes around Kondo regime with spin-flip scattering in the dot. Using a slave-boson mean field approach for the Anderson Hamiltonian having finite on-site Coulomb repulsion, we find that a spin-flip scattering always depresses the Kondo correlation at arbitrary polarization strength in both parallel and antiparallel alignment of the lead magnetization and that it effectively reinforces the tunneling related conductance in the antiparallel configuration. For systems deep in the Kondo regime, the zero-bias single Kondo peak in the differential conductance is split into two peaks by the intradot spin-flip scattering; while for systems somewhat further from the Kondo center, the spin-flip process in the dot may turn the zero-bias anomaly into a three-peak structure.Comment: 4 pages, 2 figure

    Exclusive B>π+B --> \pi \ell^+ \ell^- and B>ρ+B --> \rho \ell^+ \ell^- Decays in the Universal Extra Dimension

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    We investigate the influence of the universal extra dimension on the branching ratio in the Bπ(ρ)+B \to \pi(\rho) \ell^+ \ell^- decay. Taking 1/R{2001000}1/R\sim \{200-1000\}GeV with one universal extra spatial dimension, which is consistent with the experimental data for B(BXsγ){\cal B}(B \to X_s \gamma) , B(BKμ+μ{\cal B}(B \to K^\ast \mu^+\mu^- ) and the electroweak precision tests, we obtain that for both (μ,τ\mu,\tau) channels the branching ratio strongly depends on the compactification radius 1/R.Comment: 14 pages, 4 figure

    Atomically flat interface between a single-terminated LaAlO3 substrate and SrTiO3 thin film is insulating

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    The surface termination of (100)-oriented LaAlO3 (LAO) single crystals was examined by atomic force microscopy and optimized to produce a single-terminated atomically flat surface by annealing. Then the atomically flat STO film was achieved on a single-terminated LAO substrate, which is expected to be similar to the n-type interface of two-dimensional electron gas (2DEG), i.e., (LaO)-(TiO2). Particularly, that can serve as a mirror structure for the typical 2DEG heterostructure to further clarify the origin of 2DEG. This newly developed interface was determined to be highly insulating. Additionally, this study demonstrates an approach to achieve atomically flat film growth based on LAO substrates.Comment: 4 pages, 3 figure
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