35 research outputs found

    Effectiveness of distributed temperature measurements for early detection of piping in river embankments

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    Abstract. Internal erosion is the cause of a significant percentage of failure and incidents involving both dams and river embankments in many countries. In the past 20 years the use of fibre-optic Distributed Temperature Sensing (DTS) in dams has proved to be an effective tool for the detection of leakages and internal erosion. This work investigates the effectiveness of DTS for dike monitoring, focusing on the early detection of backward erosion piping, a mechanism that affects the foundation layer of structures resting on permeable, sandy soils. The paper presents data from a piping test performed on a large-scale experimental dike equipped with a DTS system together with a large number of accompanying sensors. The effect of seepage and piping on the temperature field is analysed, eventually identifying the processes that cause the onset of thermal anomalies around piping channels and thus enable their early detection. Making use of dimensional analysis, the factors that influence this thermal response of a dike foundation are identified. Finally some tools are provided that can be helpful for the design of monitoring systems and for the interpretation of temperature data

    On distributed strains in a CFA pile via DFOSs measurements and numerical analysis

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    Fibre Optic Sensors (FOSs) offer unprecedented possibilities for the monitoring of engineering structures, such as foundation systems. Notably, the type of FOSs known as Distributed Fibre Optic Sensors (DFOSs) has the capability of monitoring variations in the observed physical field, such as strain and temperature, with spatial continuity along the fibre. This paper presents and discusses the distributed strain measurements collected along a continuous flight auger (CFA) pile, belonging to the foundation raft of a new bridge subjected to an acceptance static load test. The monitoring was performed using a DFOS system, which works according to the optical frequency domain reflectometry (OFDR) method and provides a spatial resolution of 10 mm and a strain resolution of 1 \u3bc\u3b5. The in-situ monitoring results were used to calibrate a 3D Finite Element Model of the foundation system. The soil properties for the numerical model were also selected on the basis of a load test previously carried out on a similar pile at the same sit

    Antiepileptic drugs’ tolerability and safety – a systematic review and meta-analysis of adverse effects in dogs

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    <p>Various anti-epileptic drugs (AEDs) are used for the management of idiopathic epilepsy (IE) in dogs. Their safety profile is an important consideration for regulatory bodies, owners and prescribing clinicians. However, information on their adverse effects still remains limited with most of it derived from non-blinded non-randomized uncontrolled trials and case reports.</p><p><span>This poster won third place, which was presented at the Veterinary Evidence Today conference, Edinburgh November 1-3, 2016. </span></p><br /> <img src="https://www.veterinaryevidence.org/rcvskmod/icons/oa-icon.jpg" alt="Open Access" /

    International Veterinary Epilepsy Task Force Consensus Proposal: Outcome of therapeutic interventions in canine and feline epilepsy

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    Common criteria for the diagnosis of drug resistance and the assessment of outcome are needed urgently as a prerequisite for standardized evaluation and reporting of individual therapeutic responses in canine epilepsy. Thus, we provide a proposal for the definition of drug resistance and partial therapeutic success in canine patients with epilepsy. This consensus statement also suggests a list of factors and aspects of outcome, which should be considered in addition to the impact on seizures. Moreover, these expert recommendations discuss criteria which determine the validity and informative value of a therapeutic trial in an individual patient and also suggest the application of individual outcome criteria. Agreement on common guidelines does not only render a basis for future optimization of individual patient management, but is also a presupposition for the design and implementation of clinical studies with highly standardized inclusion and exclusion criteria. Respective standardization will improve the comparability of findings from different studies and renders an improved basis for multicenter studies. Therefore, this proposal provides an in-depth discussion of the implications of outcome criteria for clinical studies. In particular ethical aspects and the different options for study design and application of individual patient-centered outcome criteria are considered

    Caratterizzazione geotecnica, meccanismi di collasso e monitoraggio degli argini fluviali - Relazione generale

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    La relazione generale prende in esame alcuni aspetti geotecnici degli argini fluviali. Dopo una breve ricostruzione degli studi geotecnici, condotti a partire dalla storica rotta del Po del 1951, si considerano gli elementi che compongono una struttura arginale con riferimento alla costruzione di una nuova opera e al rinforzo di una esistente. Si illustrano quindi le varie tecniche di indagine per la stima delle caratteristiche geotecniche del corpo arginale e del terreno di fondazione e, successivamente, si esaminano i principali tipi di meccanismi di rottura arginale. Infine si commentano le principali metodologie di monitoraggio, tradizionale e avanzato, per un controllo della sicurezza arginale a breve e lungo termine

    Secondary compression of Venice Lagoon sands and silts from CPTU

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    A consistent database of research-quality piezocone penetration tests (CPTU) and subsoil deformation measurements, assembled within an extensive research programme carried out at the Treporti Test Site (Venice, Italy), is analyzed in order to study the secondary compression behaviour of the heterogeneous, highly stratified Venetian Lagoon silty sediments and to examine the potential use of CPTU for estimating the soil parameters describing the time-dependent mechanical response. The relationship between the cone tip resistance and the secondary compression coefficient is examined and empirical correlations are derived from field data
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