64 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
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 pecíolo 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 paquímetro. As características anatômicas foram determinadas, após a colheita, nos fragmentos de folhas e pecíolos fixos, seccionados à mão livre e fixados em glicerina, azul-de-astra ou fucsina. O estudo morfo-anatômico da folha e do pecíolo da E. macrophyllus contribuiu para ampliar e aprofundar as informações contidas nas Farmacopéias Brasileiras (1924, 1959). As características 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)
Constituents from Maytenus ilicifolia leaves and bioguided fractionation for gastroprotective activity
Maytenus ilicifolia Mart. ex Reissek is traditionally used in Brazil for treatment of gastric ulcers. Here we report the phytochemical investigation of an ethanol extract of M. ilicifolia leaves (EEMIL) aiming at the isolation of constituents which were used as chemical markers to monitor an activity-guided fractionation of a lyophilized aqueous extract of M. ilicifolia leaves (LAEMIL). From EEMIL, four flavonoids were isolated, namely the tri-flavonoid glycosides mauritianin (1), trifolin, (2) hyperin (4), and epi-catechin (5). Fractionation of LAEMIL led to 5 fractions which afforded the tetra-glycoside kaempferol derivative (3), and galactitol (6). LAEMIL and its fractions were evaluated in rats for their effects on gastric secretion volume and pH. HPLC (High Performance Liquid Chromatography) analysis revealed that only fractions containing the tri- and tetra-flavonoid glycosides 1 and 3 caused significant increase of gastric volume and pH, thus indicating that these glycosides play an important role on the gastroprotective effect of M.ilicifolia leaves.Maytenus ilicifolia Mart. ex Reissek é tradicionalmente usada no Brasil para o tratamento de úlcera gástrica. O presente trabalho relata a investigação fitoquímica de um extrato etanólico de folhas de M. ilicifolia (EEMIL) visando o isolamento de constituintes que foram usados como marcadores químicos para monitorar o fracionamento de um extrato aquoso liofilizado de folhas de M. ilicifolia (LAEMIL). De EEMIL, quatro flavonóides foram isolados, compreendendo o triglicosídeo flavônico mauritianina (1), trifolina (2), hyperina (4), e epi-catequina (5). O fracionamento de LAEMIL levou a 5 frações, fornecendo um derivado tetraglicosilado de canferol (3), além do galactitol (6). LAEMIL e suas frações foram avaliadas quanto aos efeitos sobre o volume e pH da secreção gástrica em ratos. Análise por CLAE (Cromatografia Líquida de Alta Eficiência) revelou que somente frações contendo o tri- e tetra-glicosídeos flavônicos 1 e 3 causaram aumento significativo de volume gástrico e pH, indicando que esses glicosídeos têm importante papel sob o efeito gastroprotetor de folhas de M. ilicifolia
Conservation Biogeography of the Sahara‐Sahel: additional protected areas are needed to secure unique biodiversity
Aim Identification of priority conservation areas and evaluation of coverage of
the current protected areas are urgently needed to halt the biodiversity loss.
Identifying regions combining similar environmental traits (climate regions)
and species assemblages (biogroups) is needed for conserving the biodiversity
patterns and processes. We identify climate regions and biogroups and map
species diversity across the Sahara-Sahel, a large geographical area that exhibits
wide environmental heterogeneity and multiple species groups with distinct
biogeographical affinities, and evaluate the coverage level of current network of
protected areas for biodiversity conservation.
Location Sahara-Sahel, Africa.
Methods We use spatially explicit climate data with the principal component
analysis and model-based clustering techniques to identify climate regions.
We use distributions of 1147 terrestrial vertebrates (and of 125 Sahara-Sahel
endemics) and apply distance clustering methods to identify biogroups for
both species groups. We apply reserve selection algorithms targeting 17% of
species distribution, climate regions and biogroups to identify priority areas
and gap analysis to assess their representation within the current protected
areas.
Results Seven climate regions were identified, mostly arranged as latitudinal
belts. Concentrations of high species richness were found in the Sahel, but the
central Sahara gathers most endemic and threatened species. Ten biogroups
(five for endemics) were identified. A wide range of biogroups tend to overlap
in specific climate regions. Identified priority areas are inadequately represented
in protected areas, and six new top conservation areas are needed to achieve
conservation targets.
Main conclusions Biodiversity distribution in Sahara-Sahel is spatially structured and apparently related to environmental variation. Although the majority of priority conservation areas are located outside the areas of intense
human activities, many cross multiple political borders and require internationally coordinated efforts for implementation and management. Optimized
biodiversity conservation solutions at regional scale are needed. Our work
contradicts the general idea that deserts are uniform areas and provide
options for the conservation of endangered species.info:eu-repo/semantics/publishedVersio
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