Seismic vulnerability assessment of ancient masonry building: an experimental method

This paper presents a review of the methods for seismic vulnerability assessment, together with an experimental method based on shaking table testing. This method is applied to a Portuguese masonry building typology with stone walls and timber floors, subjected to increasing earthquake damage. Traditional-like materials and techniques are used in the building. The vulnerability curves are presented and the damage indicator is correlated with the crack patterns and EMS 98

Shaking table tests of stone masonry buildings

This paper presents the main results of experimental tests concerning the reduction of the seismic vulnerability of stone masonry buildings with flexible floors. The tests were performed in the LNEC 3D shaking table by imposing artificial accelerograms in two horizontal uncorrelated orthogonal directions, triggering in-plane and out-of-plane response of two tested mock-ups; one in original condition and another repaired. The preliminary results show that adopted measures are efficient, allowing to improve the seismic performance of this building typology

Ensaios de identificação das propriedades dinâmicas de um modelo experimental de alvenaria

Em engenharia sísmica é usual recorrer-se a modelos experimentais para avaliar o desempenho sísmico das estruturas. No entanto, os modelos construídos em laboratório experimentam diferentes estágios até à realização dos ensaios sísmicos. O estudo apresentado nesta comunicação tem por objectivo avaliar a variação das propriedades dinâmicas de um modelo de alvenaria, desde os estágios após construção até ao ensaio sísmico. Neste foram realizados ensaios de vibração ambiental e forçada. Os ensaios de vibração forçada foram realizados com recurso a diferentes níveis de excitação imposta na base da estrutura, tendo por objectivo avaliar a variação dos parâmetros modais em função da amplitude do sinal de excitação. Os resultados do estudo permitiram concluir que a variação das propriedades dinâmica entre os estágios é significativa, ocorrendo acumulação de dano. Além disso, concluiu-se que o modelo apresenta comportamento não linear, função das amplitudes dos sinais de excitação utilizados em ensaios de vibração forçada

Desempenho sísmico de edifícios antigos de alvenaria: ensaios em plataforma sísmica

Este artigo apresenta os ensaios realizados na plataforma sísmica do Laboratório Nacional de Engenharia Civil sobre o desempenho sísmico de edifícios antigos de alvenaria. O programa experimental envolveu a definição de um protótipo representativo das características correntes dos edifícios gaioleiros, que posteriormente foi utilizado para a construção dos modelos experimentais. Devido às dimensões e limite de capacidade de carga da plataforma sísmica, foram ensaiados dois modelos experimentais à escala reduzida: modelo não reforçado e reforçado. No modelo reforçado utilizaram-se elementos metálicos para melhorar a ligação entre as paredes e os pavimentos, e tirantes nos pisos superiores. Os ensaios permitiram obter as propriedades dinâmicas dos modelos, as curvas de vulnerabilidade, os padrões de fendilhação e os mecanismos de colapso, bem como concluir sobre a eficiência da técnica de reforço adotada na redução da vulnerabilidade dos edifícios gaioleiros. As curvas de vulnerabilidade sísmica obtidas através dos ensaios de identificação dinâmica demostraram que o modelo reforçado apresenta uma redução do indicador de dano de cerca de 50% relativamente ao modelo não reforçado

O desafio da previsão do comportamento fora-do-plano de edifícios existentes de alvenaria

O comportamento sísmico de estruturas existentes em alvenaria é muito condicionado pelo seu comportamento fora-do-plano, originando os chamados mecanismos locais, existindo diversas metodologias que tentam prever o comportamento deste tipo de estruturas e/ou modos de colapso. Este trabalho pretende resumir os principais resultados obtidos num evento subordinado ao tema “Methods and challenges on the out-of-plane assessment of existing masonry buildings”, inserido na 9th IMC (2014) em Guimarães, com o objectivo de prever o comportamento de duas estruturas em alvenaria utilizando métodos de análise correntemente utilizados na análise sísmica de estruturas existentes. Relativamente às estruturas estudadas, uma destas era materializada em alvenaria tradicional de pedra de dois panos, sendo a outra construída em alvenaria de tijolo. Estas estruturas foram ensaiadas à escala real na mesa sísmica do LNEC. No final do presente artigo apresentam-se os principais resultados obtidos com as simulações realizadas e sua comparação com o comportamento real das estruturas.The seismic behaviour of existing masonry buildings is governed by the out-of-plane behaviour in the form of the so-called local mechanisms. Despite recent advances within the area, there are several different methodologies to predict the behaviour of these local mechanisms. The article herein submitted aims to present the main results obtained on a workshop entitled “Methods and challenges on the out-of-plane assessment of existing masonry buildings”, within the 9th IMC (2014) held at Guimarães, with the objective of predict the behaviour of masonry structures making use of any available method for the seismic analysis. Regarding the studied structures, one was built on traditional doubleleaf stone masonry while the other was built on brick masonry, and they were tested at LNEC shaking table. The main conclusions are presented at the end of the article, namely the obtained results with the prediction and the observed experimental behavior

Padrão de prescrição de psicofármacos em unidades de internamento agudo de serviços de psiquiatria em Portugal

RESUMO: Os psicofármacos desempenham um papel central no tratamento das doenças mentais. Apesar das divergências verificadas nos padrões de prescrição de psicofármacos intra e inter países, diversos estudos têm alertado para os riscos da polifarmácia e da sobredosagem, particularmente de antipsicóticos. Em Portugal, o Plano Nacional de Saúde Mental 2007-2016 prevê a monitorização periódica do padrão de prescrição de psicofármacos. No entanto, apenas existem dados relativos à utilização de psicofármacos em ambulatório, faltando dados relativos ao padrão de prescrição nos cuidados especializados. Este estudo teve como principal objetivo estabelecer o Padrão de Prescrição de Psicofármacos em Unidades de Internamento Agudo de Serviços de Psiquiatria em Portugal e determinar a prevalência da polifarmácia e sobredosagem antipsicótica, de modo a recolher dados que possam servir de base para posteriores monitorizações. Métodos: “Censo de 1 dia” da prescrição de psicofármacos em 12 Unidades de Internamento Agudo de Psiquiatria em Portugal, num total de 272 doentes. Resultados: A larga maioria (94,1%) dos doentes incluídos estava medicada com mais do que um psicofármaco. Apenas 1,1% dos doentes não tinham qualquer psicofármaco prescrito e 4,8% encontravam-se em monoterapia. A média de psicofármacos prescritos por doente era de 3,2±1,3, significativamente superior nos indivíduos do sexo feminino, naqueles com antecedentes de acompanhamento em consulta de psiquiatria, nos que tinham internamentos prévios e nos que estavam internados voluntariamente. As classes de psicofármacos mais prescritas de modo regular eram os antipsicóticos (prescritos a 87,5% dos doentes), as benzodiazepinas (81,2% dos doentes), os antidepressivos (39% dos doentes) e os estabilizadores de humor (31,6% dos doentes). Dos doentes medicados com antipsicóticos, 41,6% tinham prescritos pelo menos 2 antipsicóticos em associação e esta prescrição combinada era significativamente superior nos doentes com internamento prévio e naqueles que tinham prescrito um antipsicótico injetável de ação prolongada. Excluindo as prescrições em SOS, encontraram-se prescritas doses de antipsicóticos superiores às recomendadas em 13,9% dos doentes, os quais eram significativamente mais novos. A sobredosagem antipsicótica era significativamente superior nos doentes do sexo masculino, nos desempregados e reformados, naqueles com internamento prévio, nos que estavam internados compulsivamente, naqueles com diagnóstico de “esquizofrenia ou outra psicose”, naqueles medicados com antipsicóticos em associação e nos que faziam antipsicóticos injetáveis de ação prolongada. Incluindo as prescrições de antipsicóticos em SOS, presentes em mais de metade dos doentes, a percentagem de doentes em sobredosagem antipsicótica atingia os 49,2%. Conclusão: Os resultados são indicadores de práticas de prescrição divergentes das recomendadas, o que pode ter implicações clínicas e económicas. Parece imperativo otimizar a prescrição de psicofármacos nas unidades de internamento agudo de psiquiatria em Portugal, no sentido de melhorar a qualidade dos serviços prestados ---------------- ABSTRACT: Psychotropic drugs play a central role in the treatment of mental disorders. Despite the variation in patterns of psychotropic prescription within and between countries, several studies have warned about the risks of prescribing more than one psychotropic drug at a time and “high-doses”, particularly antipsychotics. The Portuguese National Mental Health Plan (2007–2016) includes regular monitoring of patterns of psychiatric drug prescription. However, there is only available data on the pattern of use in outpatients, but no information regarding prescribing patterns at the level of specialized care. This study aimed to establish psychotropic drug prescribing patterns in acute psychiatric wards across Portugal and to determine the prevalence of antipsychotic polypharmacy and “high-doses” treatment, in order to collect data that can serve as a baseline for future monitoring. Methods: "One day census" of psychotropic drug prescribing in 12 Acute Inpatient Psychiatry Units in Portugal, in a total of 272 patients. Results: The majority (94.1%) of patients were treated with more than one psychotropic drug. Only 1.1% of patients had no psychotropic drugs prescribed and 4.8% were on monotherapy. The average prescribed psychotropics per patient was 3.2 ± 1.3, significantly higher in females, in patients with a psychiatry history, in patients with previous admissions and in patients admitted voluntarily. The most commonly prescribed classes of psychotropic drugs on a regular basis were: antipsychotics (87.5% of patients), benzodiazepines (81.2% of patients), antidepressants (39% of patients) and mood stabilizers (31.6% of patients). Of patients taking antipsychotics, 41.6% had at least 2 antipsychotics prescribed in combination, and this prescription combination was significantly higher in patients with previous hospitalization and those who had been prescribed a long-acting injectable antipsychotic. Excluding p.r.n. prescriptions, we verified higher than recommended antipsychotic doses in 13.9% of patients, which were significantly younger. Antipsychotic “high-doses” was significantly higher in males, unemployed and pensioner patients, patients with previous hospitalization, involuntary admitted patients, those diagnosed with "schizophrenia or other psychosis", patients with a combination of 2 or more antipsychotics and in patients with long-acting injectable antipsychotics. Including antipsychotics p.r.n. prescriptions, present in more than a half of patients, the percentage of those on antipsychotic “high-doses” reached 49.2%. Conclusion: These results are indicative of prescribing practices divergent of those that are recommended, and this may have clinical and economic implications. It seems imperative to optimize the prescription of psychotropic drugs in Portuguese Acute Inpatient Psychiatry Units, in order to improve the quality of services provided

NEAR INFRARED SPECTROSCOPY TO EVALUATE COMPOSITION OF AGRO-BASED PARTICLEBOARDS

Particleboards can be manufactured from particles of any lignin-cellulosic material that can be combined with an adhesive and consolidated under the action of temperature and pressure. Because the raw materials in the industrial process are continually changing, the particleboard industry requires methods for monitoring the quality of their products. Hence, the aim of this paper was to evaluate the composition of the agro-based particleboards by near infrared spectroscopy. In this study, agro-based particleboards produced with different compositions of Eucalyptus and Pinus wood particles and sugar cane bagasse were evaluated by NIR spectroscopy and partial least square (PLS) regression. The PLS models to estimate the Eucalyptus and Pinus particles and sugar cane bagasse contents presented a strong coefficient of determination (0.90, 0.88 and 0.84, respectively), but also high magnitudes of standard errors of cross-validation were observed (ranging from 8.84 to 11.27%). Development work would be required in order to reduce the standard errors and improve predictive model performance to build robust models that could be applied as quality control tool

Estimation of physical and mechanical properties of agro-based particleboards by near infrared spectroscopy

International audiencePartial least square regression (PLS-R) calibrations based on near infrared (NIR) spectroscopic data were developed in order to predict mechanical and physical properties of agro-based particleboards. The panels were manufactured using and wood particles and sugar cane bagasse. The following panel properties were evaluated according to standard methods: modulus of elasticity (MOE), modulus of rupture (MOR), internal bonding (IB) strength, water absorption (WA24H), and thickness swelling (TS24H) after 24 hours of immersion. NIR spectra information was measured on samples cut from each particleboard and correlated with their physical and mechanical properties by PLS-R to build predictive NIR models. The NIR models for IB, WA24H and TS24H presented satisfactory coefficient of determination (0.73; 0.72 and 0.75, respectively.) The key role of resins (adhesives), cellulose, and lignin for NIRS calibrations of mechanical and physical properties of the particleboards is shown. These models can be useful to quickly verify such properties in unknown agro-based particleboards

Cutting Edge of Traumatic Maculopathy with Spectral-domain Optical Coherence Tomography – A Review

This article reviews clinically relevant data regarding traumatic maculopathy (TM), frequently observed in clinical practice, especially due to sport or traffic accident injuries. It is characterized by transient gray-whitish retinal coloration and reduction of visual acuity (VA) with closed, blunt object globe trauma of their prior. It may be limited to the posterior pole (Berlin’s edema), or peripheral areas of the retina. Spectral-domain optical coherence tomography (SD-OCT) provides detail insight using high resolution cross-sectional tomographs of the ocular tissue. It is a potent non-invasive tool for the clinician to follow-up. Clinicians are, thereby empowered with a tool that enables evaluation of the retinal status and allows for prediction of the prognosis. Spectral-domain optical coherence tomography supports the idea that the major site of injury is in the photoreceptor and layers of the retinal pigment epithelium (RPE). Depending on the severity of the trauma, SD-OCT may reveal differential optical densities of intraretinal spaces ranging from disappearance of the thin hyporeflective optical space in mild lesions, or areas of disruption of the inner segment/outer segment (IS/OS) junction and hyperreflectivity of the overlying retina, pigment disorders and retinal atrophy, in more severe cases. The prognosis for recovery of vision is generally good, and improvement occurs within 3-4 weeks

Cutting Edge of Traumatic Maculopathy with Spectral-domain Optical Coherence Tomography – A Review

This article reviews clinically relevant data regarding traumatic maculopathy (TM), frequently observed in clinical practice, especially due to sport or traffic accident injuries. It is characterized by transient gray-whitish retinal coloration and reduction of visual acuity (VA) with closed, blunt object globe trauma of their prior. It may be limited to the posterior pole (Berlin’s edema), or peripheral areas of the retina. Spectral-domain optical coherence tomography (SD-OCT) provides detail insight using high resolution cross-sectional tomographs of the ocular tissue. It is a potent non-invasive tool for the clinician to follow-up. Clinicians are, thereby empowered with a tool that enables evaluation of the retinal status and allows for prediction of the prognosis. Spectral-domain optical coherence tomography supports the idea that the major site of injury is in the photoreceptor and layers of the retinal pigment epithelium (RPE). Depending on the severity of the trauma, SD-OCT may reveal differential optical densities of intraretinal spaces ranging from disappearance of the thin hyporeflective optical space in mild lesions, or areas of disruption of the inner segment/outer segment (IS/OS) junction and hyperreflectivity of the overlying retina, pigment disorders and retinal atrophy, in more severe cases. The prognosis for recovery of vision is generally good, and improvement occurs within 3-4 weeks