224 research outputs found
Seismic assessment of St. James church by means of pushover analysis : before and after the New Zealand earthquake
The paper presents a numerical study for the seismic assessment of the St James Church in Christchurch,
New Zealand affected by the recent 2011 earthquake and subsequent aftershocks. The structural
behaviour of the Church has been evaluated using the finite element modelling technique, in which the
nonlinear behaviour of masonry has been taken into account by proper constitutive assumptions. Two
numerical models were constructed, one incorporating the existing structural damage and the other
considering the intact structure. The validation of the numerical models was achieved by the calibration
of the damaged model according to dynamic identification tests carried out in situ after the earthquake.
Non-linear pushover analyses were carried out on both principal directions demonstrating that, as a result
of the seismic action, the Church can no longer be considered safe. Pushover analysis results of the
undamaged model show reasonable agreement with the visual inspection performed in situ, which further
validates the model used. Finally, limit analysis using macro-block analysis was also carried out to
validate the main local collapse mechanisms of the Church.(undefined
Post-earthquake numerical assessment and reinforcement of St James Church, New Zealand
This paper presents a numerical study on the seismic assessment and reinforcement of St James Church, affected
by the 2011 New Zealand Earthquake. Numerical analyses were performed using a finite element model
including the structural damage of the Church. The numerical model was calibrated against experimental results
obtained from the dynamic identification tests carried out in situ. Nonlinear pushover analyses were performed
in order to understand the structural behaviour of the damaged Church. The analysis of the results suggests that
the damaged structure is not safe according to the new national specifications. Therefore, some reinforcement
measures are needed to improve the seismic behaviour of the structure. A reinforcement solution is proposed
taking into account the historical heritage value of the building, trying to maintain as much as possible the
original aspect of the Church. Pushover analyses were also performed in the reinforced numerical model,
proving its effectiveness
Post-earthquake seismic analysis of St James church, New Zealand
The paper presents a numerical study of the seismic assessment of the St James
Church in Christchurch, New Zealand affected by the most recent 2011 earthquake and
subsequent aftershocks. Dynamic identification tests, as well as a careful visual inspection,
were performed in the Church in order to understand its structural behaviour after the
seismic action. The seismic assessment of the Church has been done using the finite
element modelling technique, in which the nonlinear behaviour of masonry has been taken
into account by proper constitutive assumptions. A model updating according to the
experimental results was carried out in order to validate the numerical model, which
includes the simulation of the damage identified in the structure. Nonlinear pushover
analyses were carried out demonstrating that, as a result of the seismic action, the Church
can no longer be considered safe.
Another numerical model was analysed, this time considering the intact structure. The
pushover analysis results of this undamaged model show good agreement with the visual
inspection performed in situ, which further validates the model used.
Moreover, since the analysis proved that the structure is no longer safe, a reinforcement
strategy is proposed and analysed, proving its effectiveness.(undefined
Simplified indexes for the seismic assessment of masonry buildings : international database and validation
Heritage masonry buildings are particularly vulnerable to earthquakes because they are deteriorated and damaged, they were built with materials with low resistance, they are heavy and the connections between the various structural components are often insufficient. The present work details a simplified method of seismic assessment of large span masonry structures that was applied to a database of forty-four monuments in Italy, Portugal and Spain, providing lower bound formulas for different simplified geometrical indexes. Subsequently, the proposed thresholds are validated with data from the 2010-2011 Canterbury earthquakes, which includes forty-eight stone and clay brick masonry churches. Finally, fragility curves that can be used to estimate the damage as a function of the peak ground acceleration (PGA) are also provided
When science fiction turns to reality: Square Kilometre Array (SKA), the largest radio telescope ever imagined'
The world's scientific community is building the largest radio telescope ever imagined, with a total collection area of one square kilometre, i.e. a million square meters. This represents a huge technological advance, massive investment, and even greater opportunities. The radio astronomers will be able to monitor the sky with unprecedented detail, sensitivity and speed, aiming to answer several fundamental questions, and creating a wide range of new technological solutions. The magnitude of this project also implies an immensely challenging task: establishing the bridges between society, political and scientific communities. SKA outreach requires the creation of innovative dissemination materials that portrait the instrument from very different perspectives, highlighting its importance to the multiple targets that its technologies address spills to. In this work we explore how concepts are exploited, creating an inspiring sci-fi vision, mostly resorting of video and 3D animations
Development of a UV/Vis spectrophotometric method for analysis of total polyphenols from Caesalpinia peltophoroides Benth
Caesalpinia peltophoroides is a domesticated tree found in Brazil. It was necessary to develop an analytical method to determine the content of total polyphenols (TP) in this herbal drug. The pre-analytical method was standardized for analysis time, wavelength, and the best standard to use. The optimum conditions were: pyrogallol, 760 nm, and 30 min respectively. Under these conditions, validation by UV/Vis spectrophotometry proved to be reliable for TP of the crude extract and semipurified fractions from C. peltophoroides. Standardization is required for every herbal drug, and this method proved to be linear, precise, accurate, reproducible, robust, and easy to perform
The influence of temperature and salinity on the impacts of lead in Mytilus galloprovincialis
Mussels, such as the marine bivalve Mytilus galloprovincialis are sentinels for marine pollution but they are also excellent bioindicators under laboratory conditions. For that, in this study we tested the modulation of biochemical responses under realistic concentrations of the toxic metal Lead (Pb) in water for 28 days under different conditions of salinity and temperature, including control condition (temperature 17 ± 1.0 °C and salinity 30 ± 1.0) as well as those within the range expected to occur due to climate change predictions (± 5 in salinity and + 4 °C in temperature). A comprehensive set of biomarkers was applied to search on modulation of biochemical responses in terms of energy metabolism, energy reserves, oxidative stress and damage occurrence in lipids, proteins as well as neurotoxicity signs. The application of an integrative Principal Coordinates Ordination (PCO) tool was successful and demonstrated that Pb caused an increase in the detoxification activity mainly evidenced by glutathione S-transferases and that the salinities 25 and 35 were, even in un-exposed mussels, responsible for cell damage seen as increased levels of lipid peroxidation (at salinity 25) and oxidised proteins (at salinity 35).publishe
Contribution to the pharmacobotanical study of Echinodorus macrophyllus (Kunth) Micheli (chapéu-de-couro) – Alismataceae
Echinodorus macrophyllus (Kunth) Micheli – Alismataceae, known as "chapéu-de-couro", "chá-mineiro", "erva-de-pântano", "erva-de-bugre", "congonha-do-brejo", "erva-do-brejo", occurs in Minas Gerais and São Paulo. Although it has therapeutic and commercial importance and is described in the two first editions of the Brazilian Pharmacopoeia (1924, 1959), there are few studies that contemplate it. This present work had the objective to study the leaf and petiole morpho-anatomy of A. macrophyllus, in order to extend its pharmacognosy knowledge, aiming at the quality control. The macroscopic description was carried through disarmed sight, with optical resources and the dimensions with a caliper. The anatomical c haracteristics had been determined, after the harvest, in the fragments of leaves and fixed petioles, freehand sectioned and stained either in glycerin, astra-blue or fuchsine. The morpho-anatomical study of the leaf and petiole of A. macrophyllust contributed to extend and deepen the information contained in the Brazilian Pharmacopoeia (1924, 1959). The designated structural characteristics assist in the identification of the species and supply parameters that could be applied in the pharmacognosy quality control in the future. And, the presence of non-glandular trichomes in the midribs (adaxial and abaxial surface) and the petiole exhibits diaphragm (specialized cells), key structures in the diagnosis of the species, that are not described in the Brazilian Pharmacopoeia (1924, 1959), were inserted in the context of the anatomical description.A Echinodorus macrophyllus (Kunth) Micheli - Alismataceae, conhecida como chapéu-de-couro, chá-mineiro, erva-de-pantâno, erva-de-bugre, congonha-do-brejo e erva-do-brejo, ocorre em Minas Gerais e São Paulo. Embora tenha importância terapêutica, comercial e estar inscrita nas duas primeiras edições da Farmacopéia Brasileira (1924, 1959), são poucos os estudos que a contemplam. Este presente trabalho teve como objetivo estudar a morfoanatomia foliar e do pecÃolo da E. macrophyllus, a fim de ampliar o seu conhecimento farmacognóstico, visando o controle de qualidade. A descrição macroscópica foi realizada à vista desarmada, com recursos óticos e as dimensões, com paquÃmetro. As caracterÃsticas anatômicas foram determinadas, após a colheita, nos fragmentos de folhas e pecÃolos fixos, seccionados à mão livre e fixados em glicerina, azul-de-astra ou fucsina. O estudo morfo-anatômico da folha e do pecÃolo da E. macrophyllus contribuiu para ampliar e aprofundar as informações contidas nas Farmacopéias Brasileiras (1924, 1959). As caracterÃsticas estruturais assinaladas auxiliam na identificação da espécie e fornece parâmetros que poderão ser aplicados futuramente no controle de qualidade farmacognóstico. E, inseriu no contexto da descrição anatômica, a presença de pêlos tectores e de células diafragmáticas, estruturas chaves no diagnóstico da espécie, não descritas pelas Farmacopéias Brasileiras (1929, 1959)
Ecotoxicological effects of lanthanum in Mytilus galloprovincialis: biochemical and histopathological impacts
Inappropriate processing and disposal of electronic waste contributes to the contamination of aquatic systems by various types of pollutants such as the rare-earth elements (REE) in which lanthanum (La) is included. Knowledge on the toxicity of these elements in marine organisms is still scarce when compared to other metals such as mercury (Hg) and arsenic (As). Therefore, this study aims to assess the toxicity of La on the mussel Mytilus galloprovincialis, considered a good bioindicator of aquatic pollution, through the analysis of metabolic, oxidative stress, neurotoxicity and histopathological markers. Organisms were exposed to different concentrations of La for a period of 28 days (0, 0.1, 1, 10 mg/L) under controlled temperature (18 °C ± 1.0) and salinity (30 ± 1) conditions. La concentrations in mussels increased in higher exposure concentrations. La exposure demonstrated a biochemical response in mussels, evidenced by lowered metabolism and accumulation of energy reserves, activation of the antioxidant defences SOD and GPx as well as the biotransformation enzymes GSTs, especially at intermediate concentrations. Despite oxidative stress being shown by a decrease in GSH/GSSG, oxidative damage was avoided as evidenced by lower LPO and PC levels. Inhibition of the enzyme AChE demonstrated the neurotoxicity of La in this species. Histopathological indices were significantly different from the control group, indicating impacts in gonads, gills and digestive glands of mussels due to La. These results show that La can be considered a risk for marine organisms and thus its discharge into the environment should be monitored.publishe
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