405 research outputs found

    Robustness of timber structures in seismic areas

    Get PDF
    Major similarities between robustness assessment and seismic design exist, and significant information can be brought from seismic design to robustness design. As will be discussed, although some methods and limitations considered in seismic design can improve robustness, the capacity of the structure to sustain limited damage without disproportionate effects is significantly more complex. In fact, seismic design can either improve or reduce the resistance of structures to unforeseeable events, depending on the structural type, triggering event, structural material, among others. Based on a case study, the influence of redundancy and ductility on the seismic behavior and robustness of a long-span timber structure is assessed.COST E 5

    Simulation-Based Decision Support System for Energy Efficiency in Buildings Retrofitting

    Get PDF
    Funding Information: This research was developed under project EnPROVE (Energy Consumption Prediction with Building Usage Measurements for Software-Based Decision Support) funded by the European Union’s Seventh Framework Programme (Grant agreement ID: 248061). Partial support was also given by the Portuguese “Fundação para a Ciência e Tecnologia (FCT)” through the project UIDB/00066/2020 (Center of Technology and Systems, CTS). Publisher Copyright: © 2022 by the authors.The implementation of building retrofitting processes targeting higher energy efficiency is greatly influenced by the investor’s expectations regarding the return on investment. The baseline of this work is the assumption that it is possible to improve the predictability of the post-retrofit scenario, both in energy and financial terms, using data gathered on how a building is being used by its occupants. The proposed approach relies on simulation to estimate the impact of available energy-efficient solutions on future energy consumption, using actual usage data. Data on building usage are collected by a wireless sensor network, installed in the building for a minimum period that is established by the methodology. The energy simulation of several alternative retrofit scenarios is then the basis for the decision support process to help the investor directing the financial resources, based on both tangible and intangible criteria. The overall process is supported by a software platform developed in the scope of the EnPROVE project. The platform includes building audit, energy consumption prediction, and decision support. The decision support follows a benefits, opportunities, costs, and risks (BOCR) analysis based on the analytic hierarchy process (AHP). The proposed methodology and platform were tested and validated in a real business case, also within the scope of the project, demonstrating the expected benefits of alternative retrofit solutions focusing on lighting and thermal comfort.publishersversionpublishe

    Methodologies for teaching an engineering subject in different countries: comparison and results

    Get PDF
    Engineering or technical degrees are difficult to teach and, consequently, have always been characterized by a large number of academic failures. Therefore, continuous assessment has been applied to classes of similar content, related to Port and Coastal Engineering during these last years in three different Universities worldwide: University of La Republica (Montevideo, Uruguay), Nova de Lisboa (Portugal) and Cadiz (Spain). This paper presents different methodologies used to teach and evaluate these courses at each University, together with the results of the evaluations of the students who were enrolled during the current and previous stages. Generally, a decrease in the number of students who abandon the classes has been noticed together with an increase in the percentage of students who pass and an improvement of their grades, except at the University Nova de Lisboa were the results have remained stable. In addition, changes experienced in the courses are discussed herein by comparing the percentage of success in the different locations. Moreover, influence of the different methodologies and the possible reasons for these changes are also presented and analysed. As a conclusion, the improvement in educational outcomes has been achieved through the concurrence of different factors: the existence of more frequent written and/or oral exams, practical examples of case studies as well as access to specific tools of new technology and to documentation specifically prepared for the classes and available online. Evidently, the above mentioned tasks require a strong commitment and great effort by the teaching staff. If human resources diminish, as it is happening in Spain and Portugal due to the budget reduction in education, two difficult questions arise: For how long will teachers’ current effort be maintained? What impact will have their complete devotion to teaching in their research performance

    Morphology determined by waves in fluvial beaches. "La Concordia" in the Uruguay River, a case study.

    Get PDF
    Sediment characteristics and the direction and magnitude of the velocity of the current in the river, amongst other factors, usually established the pro file and the plan shape of fluvial beaches. However, in sorne cases, even far from its estuary or river mouth, this morphology can be determined by the incidence of the waves despite not being a marine environment. In this paper a qualitative methodology will be presented which will allow us to recognize the aspects that influence the existen ce of such morphologies. For this purpose a case study will be analyzed: the beach of La Concordia located on the left bank ofthe Uruguay River, 70 km upstreamfrom its mouth at the estuwy of Rio de la Plata. Furthermore, plan shape will be analyzed and its determination by wave action will be proved.Tanto el perfil como la forma en planta de las playas fluviales vienen establecidos por numerosos factores entre los que cabría destacar las características del sedimento y la dirección y módulo de la velocidad de la corriente en el río. Sin embargo, en ciertos casos, lejos incluso de su estuario o desembocadura, esta morfología puede estar determinada principalmente por la incidencia del oleaje pese a no tratarse de un entorno marítimo. Se presenta aquí una metodología cualitativa que nos permitirá reconocer los aspectos que influyen en la existencia de este tipo de morfologías. Para ello, se estudiará un caso particular, el de la playa de La Concordia ubicada en la margen izquierda del río Uruguay a 70 km de su desembocadura en el estuario del Rio de la Plata. Asimismo se analizará la forma en planta y se verificará que la misma está determinada por la acción del oleaje

    Experimental investigation of the flow field in the vicinity of an oscillating wave surge converter

    Get PDF
    PTDC/CTAOHR/30561/2017 PD/BD/705970/2014The main objective of this paper is to characterize the flow field on the front face of an oscillating wave surge converter (OWSC) under a regular wave. For this purpose, the longitudinal and vertical velocity components were measured using an Ultrasonic Velocity Profiler (UVP). In order to explain the main trends of the OWSC’s dynamics, the experimental data were firstly compared with the analytical results of potential theory. A large discrepancy was observed between experimental and analytical results, caused by the nonlinear behavior of wave-OWSC interaction that determine the turbulent field and the boundary layer. The experimental velocity field shows a strong ascendant flow generated by the mass transfer over the flap (overtopping) and flow rotation generated by the beginning of the flap deceleration and acceleration. These features (overtopping and flow rotation) have an important role on the power capture of OWSC and, therefore, analytical results are not accurate to describe the complex hydrodynamics of OWSC.publishersversionpublishe

    Implantation of intracorneal ring segments in pediatric patients: long-term follow-up

    Get PDF
    Purpose: To analyze the long-term outcomes of intracorneal ring segments (ICRS) implantation for keratoconus management in pediatric patients. Methods: Retrospective case series review of the long-term (>5 years) outcomes of Intacs® ICRS implantation for keratoconus in pediatric patients (age <18 years old at the time of surgery) between January 2008 and December 2011 at Ophthalmology Department of Hospital de Santo António. Demographic data, follow-up time, preoperative and postoperative uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA) in decimal scale, and corneal topography were evaluated. Statistical analysis was done using SPSS for windows (version 24). Significance was set at p<0.0125. Results: Fourteen eyes of 14 patients, with a mean age of 15.36 years (range 10-18 years), were included in this study. All patients had been diagnosed with keratoconus with reported progression in the 6 months prior to surgery. Follow-up time was 6.36±0.97 years. UCVA and BCVA improved after ICRS implantation (p<0.0125). Keratometry (K) minimum (Kmin) and K maximum (Kmax) decreased after surgery (p<0.0125). During follow-up, UCVA, BCVA, Kmin, and Kmax values ranged, showing a tendency to worsen at the end of follow-up. However, statistically significant differences were not observed. Conclusion: ICRS implantation showed good visual and topographic results in pediatric patients. Long-term follow-up suggests that, despite ICRS implantation, there is still progression of keratoconus. To the best of our knowledge, there are no reports regarding the long-term efficacy of ICRS implantation in pediatric patients.info:eu-repo/semantics/publishedVersio

    Deterioration modeling of steel moment resisting frames using finite-length plastic hinge force-based beam-column elements

    Get PDF
    The use of empirically calibrated moment-rotation models that account for strength and stiffness deterioration of steel frame members is paramount in evaluating the performance of steel structures prone to collapse under seismic loading. These deterioration models are typically used as zero-length springs in a concentrated plasticity formulation; however, a calibration procedure is required when they are used to represent the moment-curvature (M−χ) behavior in distributed plasticity formulations because the resulting moment-rotation (M−θ) response depends on the element integration method. A plastic hinge integration method for using deterioration models in force-based elements is developed and validated using flexural stiffness modifications parameters to recover the exact solution for linear problems while ensuring objective softening response. To guarantee accurate results in both the linear and nonlinear range of response, the flexural stiffness modification parameters are computed at the beginning of the analysis as a function of the user-specified plastic hinge length. With this approach, moment-rotation models that account for strength and stiffness deterioration can be applied in conjunction with force-based plastic hinge beam-column elements to support collapse prediction without increased modeling complexity

    Short-communication: study of fatty acid metabolites in microbial conjugated fatty acids-enrichment of milk and discovery of additional undescribed conjugated linolenic acid isomers

    Get PDF
    Microbially enriched food in conjugated linoleic (CLA) and conjugated linolenic (CLNA) acids is intensively studied nowadays. The conversion of linoleic (LA) and α-linolenic acids (α-LNA) into these compounds may involve different fatty acid (FA) intermediates. This research aimed to investigate potential FA byproducts in milk during microbial CLA/CLNA-enrichment using Bifidobacterium breve DSM 20091. Milk fermented with pure α-LNA showed a decrease in free myristic acid, while pure LA led to an increase in free stearic acid. No additional FA compounds were found alongside CLA/CLNA isomers. The strain produced several CLA isomers from LA, but only when administered alone. Nonetheless, when α-LNA was assayed, additional CLNA isomers, never reported before for bifidobacteria, were observed. In conclusion, except for stearic acid in the presence of LA, no side-FA metabolites were released during milk microbial CLA/CLNA-enrichment. Results suggest either CLA/CLNA production occurs in one single-step or intermediates biotransformation is very fast.N/

    A comparison of production control systems in a flexible flow shop

    Get PDF
    Production control in make-to-order must address the companies’ need for short delivery times and on-time deliveries. Several production control systems may be used to meet these needs. This paper presents a simulation study to evaluate the delivery performance of the TKS, GKS and POLCA production co ntrol systems, in the context of a make-to-order flexible flow shop. Since TKS is used for make-to-stock manufacturing, an adaptation of it is made to use in make-to-order. Results of a simulation study show that the adapted TKS outperforms POLCA, but performs worse than GKS. The study is a contribution for the alignment of production control theory to the industrial practice.This work had the financial support of FCT- Fundacao para a Ciencia e Tecnologia of Portugal under the project PEst2015-2020: UID/CEC/00319/2013.info:eu-repo/semantics/publishedVersio

    Increased geographical distribution and richness of non-native freshwater fish species in Argentina: evidence from a literature review

    Get PDF
    The present study is a full review of the non-native freshwater fish species introduced into Argentina and their relationship to the main environmental features and introduction vectors of each freshwater ecoregion. The total number of non-native freshwater fish species was compiled through a literature survey; information on spatial–temporal patterns of species records and invasion vectors was retrieved for all ten freshwater ecoregions of Argentina. Our survey revealed that 18–22 non-native fish species had been recorded up to 1999, and a total of 40 introduced fish species, of which 18 are invasive and five potentially invasive, had been registered in seven Argentinean ecoregions as of May 2020. According to georeferenced records, the rainbow trout Oncorhynchus mykiss and common carp Cyprinus carpio were the non-native fish species with the greatest number of records and largest invaded areas, probably due to their species-specific ecological traits. Invasive fish species differed clearly between the Patagonia, Lower Paraná, and Lower Uruguay ecoregions, probably because of a combination of the environmental conditions, structure of native assemblages, and invasion pathways in each ecoregion. Except for the recognized impact of non-native salmonids, the adverse effects of introduced fish species have been little studied, indicating the need for further research to clarify the role of ecological shifts triggered by the introduction and establishment of non-native fish species in Argentina. In contrast to the high diversity of aquatic species and freshwater environments, the spread and impact of invasive fish species in Argentina is little known, particularly compared with other South American countries.Fil: Espínola, Luis Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Rabuffetti, Ana Pia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Carrara, Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Abrial, Elie. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Ferlay, Elise Mathilde Charlotte. Polytechnic School Of The University Of Tours; FranciaFil: Yoya, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Blettler, Martin Cesar Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Baigún, Claudio Rafael M.. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Wantzen, Karl Matthias. Centre National de la Recherche Scientifique; FranciaFil: Neves dos Santos, Luciano. Universidade Federal do Estado do Rio de Janeiro; Brasi
    corecore