1,016 research outputs found

    Intrapatient variability of the pupillary pain index to remifentanil

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    A Fibre-Based Frame Element with Explicit Consideration of Bond-Slip Effects

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    Reinforced concrete (RC) frames subjected to seismic loading often depict localized member-end deformations due to strain penetration effects between adjacent members, such as beam-column and column-footing joints. Past experimental programs indicate that the bond-slip deformations occurring at the interface between the reinforcement and the surrounding concrete can contribute up to 40% of the lateral deformation of the RC members. The employment of advanced bond-slip models within detailed finite element formulations, capable of simulating continuous domains with highly discretized meshes, has witnessed great advances over the recent years with encouraging results. Nonetheless, this modelling approach is computationally heavy and hence inapplicable for practical seismic (nonlinear) analysis of structures. Alternatively, the use of beam-column elements with lumped or distributed plasticity is a more computationally efficient and engineering-friendly modelling approach. Unfortunately, the elements of this type available in conventional numerical packages did not yet consider an explicit simulation of the interface between the reinforcing bars and the surrounding concrete along their embedment length. The present study aimed at overcoming the foregoing limitation by developing an explicit bond-slip model applicable to general fibre-based beam-column elements. Using a state-of-the-art bond-slip constitutive model, the current paper introduces a zero-length element that computes the localized member-end deformations accounting for the bond-slip response at each reinforcing bar of a given RC section. Along with the material properties and anchorage conditions, the proposed nonlinear model also accounts for cyclic degradation and rebar yielding effects. Validation studies conducted with the proposed numerical formulation reveal a good agreement with past experimental tests, evidencing an important stability and accuracy at the expense of an acceptable additional computational effort.info:eu-repo/semantics/publishedVersio

    Blind Prediction Tests as a Benchmark to Improve the Seismic Response of Fibre Models

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    The seismic behaviour of reinforced concrete framed structures involves a number of nonlinear material and geometrical phenomena that are impossible to model exhaustively in a single model. Furthermore, past studies showed that the most correct modelling options from the scientific viewpoint are sometimes challenged by experimental results. Over the years, attempts have been made to identify and measure the importance of different modelling options. This work intends to consolidate some of these findings and further extend them in order to progressively bridge the gap between solidly established theoretical principles and shaking table test results. The response of three different structures used in international blind prediction test challenges serves as benchmark to assess the goodness-of-fit of alternative numerical solutions. The interpretation of the results highlights the sensitivity of the response with respect to the modelling choices and provides indications towards the development of optimized numerical analyses.N/

    Pupillary pain index correlates in increasing concentrations of remifentanil

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    Optimizing sealed transports of small ornamental fish

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    This is a report on multiple simulated long-term transports of small ornamental fish inside plastic bags. The species involved were Diplodus sargus, Gobius paganellus, Gobiusculus flavescens, Lepadogaster lepadogaster and Lipophrys pholis. The objective of such simulations was moving the maximum bioload possible while ensuring 100% survivorship, ultimately resulting in savings for the end-receiver. Transports were simulated over 24, 48 and 72 hours, with increasing animal bioloads per bag. Half of the trials were performed with “regular” saltwater while the other half involved seawater buffered with Amquel ®, sodium carbonate and sodium bicarbonate, with the objective of keeping ammonia low and pH similar to initial baseline values. At the end of each trial, temperature, dissolved oxygen, pH and ammonia were analized and the survival rate calculated and recorded. L. lepadogaster endured the highest bioloads at 100% survivorship (i.e. up to 30 g / L), which is not surprising given the intertidal nature of this species. D. sargus exhibited mortalities with bioloads as low as 3,23 g / L, which echoes its predominantly pelagic nature and relatively lesser ability to endure confinement. The three remaining species showed varying degrees of tolerance to increasing bioloads in transport: L. pholis , also an intertidal species, handled up to 20 g/L over 72 hours, while G. paganellus handled up to 7 g/L over 72 hours, and G. flavescens (a predominantly pelagic species) could deal with no more than 6 g/L up to 72 hours.info:eu-repo/semantics/publishedVersio
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