Uncertainty assessment approach for composite structures based on global sensitivity indices

The problem of uncertainty propagation in composite laminate structures is studied. An approach based on the optimal design of composite structures to achieve a target reliability level is proposed. Using the Uniform Design Method (UDM), a set of design points is generated over a design domain centred at mean values of random variables, aimed at studying the space variability. The most critical Tsai number, the structural reliability index and the sensitivities are obtained for each UDM design point, using the maximum load obtained from optimal design search. Using the UDM design points as input/output patterns, an Artificial Neural Network (ANN) is developed based on supervised evolutionary learning. Finally, using the developed ANN a Monte Carlo simulation procedure is implemented and the variability of the structural response based on global sensitivity analysis (GSA) is studied. The GSA is based on the first order Sobol indices and relative sensitivities. An appropriate GSA algorithm aiming to obtain Sobol indices is proposed. The most important sources of uncertainty are identified.

Corrosão das armaduras do betão armado: causas, consequências, prevenção e projeto de durabilidade

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia Civil

Gender and racial inequalities in trends of oral cancer mortality in Sao Paulo, Brazil

OBJECTIVE:To analyse recent trends in oral cancer mortality, focusing specifically on differences concerning gender and race.METHODS:Official information on deaths and population in the city of Sao Paulo, 2003 to 2009, were used to estimate mortality rates from oral cancer (C00 to C10, International Classification of Diseases, 10th Revision), adjusted for age and stratified by gender (females and males) and race (blacks and whites). The Prais-Winsten auto-regression procedure was used to analyse the time series.RESULTS:During the study period, 8,505 individuals living in the city of Sao Paulo died of oral cancer. Rates increased for females (rate of yearly increase = 4.4%, 95%CI 1.4;7.5), and levelled off for men, which represents an inversion of previous trends among genders in the city. Increases were identified for blacks, with a high rate of yearly increase of 9.1% (95%CI 5.5;12.9), and levelled off for whites. Oral cancer mortality in blacks almost doubled during the study period, and surpassed mortality in whites for almost all categories.CONCLUSIONS:Mortality presented a higher increase among women than in men, and it doubled among backs. The surveillance of trends of oral cancer mortality across gender and racial groups may contribute to implementing socially appropriate health policies, which concurrently reduce the burden of disease and the attenuation of unfair, avoidable and unnecessary inequalities in health.

Evolução tectónica mesozóica da Bacia Lusitaniana

The evolution of the Lusitanian Basin, localized on the western Iberian margin, is closely associated with the first opening phases of the North Atlantic. It persisted from the Late Triassic to the Early Cretaceous, more precisely until the end of the Early Aptian, and its evolution was conditioned by inherited structures from the variscan basement. The part played by the faults that establish its boundaries, as regards the geometric and kinematic evolution and the organization of the sedimentary bodies, is discussed here, as well as with respect to important faults transversal to the Basin. A basin evolution model is proposed consisting of four rifting episodes which show: i) periods of symmetrical (horst and graben organization) and asymmetrical (half graben organization) geometric evolution; ii) diachronous fracturing; iii) rotation of the main extensional direction; iv) rooting in the variscan basement of the main faults of the basin (predominantly thick skinned style). The analysis and regional comparison, particularly with the Algarve Basin, of the time intervals represented by important basin scale hiatuses near to the renovation of the rifting episodes, have led to assume the occurrence of early tectonic inversions (Callovian–Oxfordian and Tithonian–Berriasian). The latter, however, had a subsequent evolution distinct from the first: there is no subsidence renovation, which is discussed here, and it is related to a magmatic event. Although the Lusitanian Basin is located on a rift margin which is considered non-volcanic, the three magmatic cycles as defined by many authors, particularly the second (approx. 130 to 110 My ?), performed a fundamental part in the mobilization of the Hettangian evaporites, resulting in the main diapiric events of the Lusitanian Basin. The manner and time in which the basin definitely ends its evolution (Early Aptian) is discussed here. Comparisons are established with other west Iberian margin basins and with Newfoundland basins. A model of oceanization of this area of the North Atlantic is also presented, consisting of two events separated by approximately 10 My, and of distinct areas separated by the Nazaré fault. The elaboration of this synthesis was based on: - information contained in previously published papers (1990 – 2000); - field-work carried out over the last years, the results of which have not yet been published; - information gathered from the reinterpretation of geological mapping and geophysical (seismic and well logs) elements, and from generic literature concerning the Mesozoic of the west iberian margin.

Tendência secular da amamentação no Brasil

Com o objetivo de documentar a tendência secular da amamentação no Brasil, foram reanalisadas as bases de dados de sete pesquisas nacionais realizadas de 1975 a 2008. Para obter dados comparáveis entre os diferentes inquéritos, foram analisadas as mesmas faixas etárias e indicadores, e utilizadas as mesmas técnicas estatísticas. A duração mediana da amamentação aumentou de 2,5 para 11,3 meses e a prevalência da amamentação exclusiva em menores de seis meses passou de 3,1% para 41,0% no período. Os resultados apontam importantes desafios no sentido de acelerar o ritmo de crescimento dessa prática no País, rumo às recomendações internacionais.

Uncertainty analysis based on sensitivity applied to angle-ply composite structures

This article describes a finite element-based formulation for the statistical analysis of the response of stochastic structural composite systems whose material properties are described by random fields. A first-order technique is used to obtain the second-order statistics for the structural response considering means and variances of the displacement and stress fields of plate or shell composite structures. Propagation of uncertainties depends on sensitivities taken as measurement of variation effects. The adjoint variable method is used to obtain the sensitivity matrix. This method is appropriated for composite structures due to the large number of random input parameters. Dominant effects on the stochastic characteristics are studied analyzing the influence of different random parameters. In particular, a study of the anisotropy influence on uncertainties propagation of angle-ply composites is carried out based on the proposed approach.

From local to global importance measures of uncertainty propagation in composite structures

The influence of uncertainties of input parameters on output response of composite structures is investigated in this paper. In particular, the effects of deviations in mechanical properties, ply angles, ply thickness and on applied loads are studied. The uncertainty propagation and the importance measure of input parameters are analysed using three different approaches: a first-order local method, a Global Sensitivity Analysis (GSA) supported by a variance-based method and an extension of local variance to estimate the global variance over the domain of inputs. Sample results are shown for a shell composite laminated structure built with different composite systems including multi-materials. The importance measures of input parameters on structural response based on numerical results are established and discussed as a function of the anisotropy of composite materials. Needs for global variance methods are discussed by comparing the results obtained from different proposed methodologies. The objective of this paper is to contribute for the use of GSA techniques together with low expensive local importance measures.

Uncertainty propagation in inverse reliability-based design of composite structures

An approach for the analysis of uncertainty propagation in reliability-based design optimization of composite laminate structures is presented. Using the Uniform Design Method (UDM), a set of design points is generated over a domain centered on the mean reference values of the random variables. A methodology based on inverse optimal design of composite structures to achieve a specified reliability level is proposed, and the corresponding maximum load is outlined as a function of ply angle. Using the generated UDM design points as input/output patterns, an Artificial Neural Network (ANN) is developed based on an evolutionary learning process. Then, a Monte Carlo simulation using ANN development is performed to simulate the behavior of the critical Tsai number, structural reliability index, and their relative sensitivities as a function of the ply angle of laminates. The results are generated for uniformly distributed random variables on a domain centered on mean values. The statistical analysis of the results enables the study of the variability of the reliability index and its sensitivity relative to the ply angle. Numerical examples showing the utility of the approach for robust design of angle-ply laminates are presented.

Operational modal monitoring of ancient structures using wireless technology

Operational Modal Analysis is currently applied in structural dynamic monitoring studies using conventional wired based sensors and data acquisition platforms. This approach, however, becomes inadequate in cases where the tests are performed in ancient structures with esthetic concerns or in others, where the use of wires greatly impacts the monitoring system cost and creates difficulties in the maintenance and deployment of data acquisition platforms. In these cases, the use of sensor platforms based on wireless and MEMS would clearly benefit these applications. This work presents a first attempt to apply this wireless technology to the structural monitoring of historical masonry constructions in the context of operational modal analysis. Commercial WSN platforms were used to study one laboratory specimen and one of the structural elements of a XV century building in Portugal. Results showed that in comparison to the conventional wired sensors, wireless platforms have poor performance in respect to the acceleration time series recorded and the detection of modal shapes. However, for frequency detection issues, reliable results were obtained, especially when random excitation was used as noise source.

Practices and trends of telework in the Portuguese industry: the results of surveys in the textile, metal and software sectors

The aim of the TeleRisk Project on labour relations and professional risks within the context of teleworking in Portugal – supported by IDICT – Institute for Development and Inspection of Working Conditions (Ministry of Labour), is to study the practices and forms of teleworking in the manufacturing sectors in Portugal. The project chose also the software industry as a reference sector, even though it does not intend to exclude from the study any other sector of activity or the so-called “hybrid” forms of work. However, the latter must have some of the characteristics of telework. The project thus takes into account the so-called “traditional” sectors of activity, namely textile and machinery and metal engineering (machinery and equipment), not usually associated to this type of work. However, telework could include, in the so-called “traditional” sectors, other variations that are not found in technologically based sectors. One of the evaluation methods for the dynamics associated to telework consisted in carrying out surveys by means of questionnaires, aimed at employers in the sectors analysed. This paper presents some of the results of those surveys. It is important to mention that, being a preliminary analysis, it means that it does not pretend to have exhausted all the issues in the survey, but has meant that it shows the bigger tendencies, in terms of teleworking practices, of the Portuguese industry.

Temporal trends and spatial distribution of unsafe abortion in Brazil, 1996-2012

OBJECTIVE To analyze temporal trends and distribution patterns of unsafe abortion in Brazil. METHODS Ecological study based on records of hospital admissions of women due to abortion in Brazil between 1996 and 2012, obtained from the Hospital Information System of the Ministry of Health. We estimated the number of unsafe abortions stratified by place of residence, using indirect estimate techniques. The following indicators were calculated: ratio of unsafe abortions/100 live births and rate of unsafe abortion/1,000 women of childbearing age. We analyzed temporal trends through polynomial regression and spatial distribution using municipalities as the unit of analysis. RESULTS In the study period, a total of 4,007,327 hospital admissions due to abortions were recorded in Brazil. We estimated a total of 16,905,911 unsafe abortions in the country, with an annual mean of 994,465 abortions (mean unsafe abortion rate: 17.0 abortions/1,000 women of childbearing age; ratio of unsafe abortions: 33.2/100 live births). Unsafe abortion presented a declining trend at national level (R2: 94.0%, p < 0.001), with unequal patterns between regions. There was a significant reduction of unsafe abortion in the Northeast (R2: 93.0%, p < 0.001), Southeast (R2: 92.0%, p < 0.001) and Central-West regions (R2: 64.0%, p < 0.001), whereas the North (R2: 39.0%, p = 0.030) presented an increase, and the South (R2: 22.0%, p = 0.340) remained stable. Spatial analysis identified the presence of clusters of municipalities with high values for unsafe abortion, located mainly in states of the North, Northeast and Southeast Regions. CONCLUSIONS Unsafe abortion remains a public health problem in Brazil, with marked regional differences, mainly concentrated in the socioeconomically disadvantaged regions of the country. Qualification of attention to women’s health, especially to reproductive aspects and attention to pre- and post-abortion processes, are necessary and urgent strategies to be implemented in the country.

Trends in public health policies addressing violence against women

OBJECTIVE To analyze the content of policies and action plans within the public healthcare system that addresses the issue of violence against women.METHODS A descriptive and comparative study was conducted on the health policies and plans in Catalonia and Costa Rica from 2005 to 2011. It uses a qualitative methodology with documentary analysis. It is classified by topics that describe and interpret the contents. We considered dimensions, such as principles, strategies, concepts concerning violence against women, health trends, and evaluations.RESULTS Thirteen public policy documents were analyzed. In both countries’ contexts, we have provided an overview of violence against women as a problem whose roots are in gender inequality. The strategies of gender policies that address violence against women are cultural exchange and institutional action within the public healthcare system. The actions of the healthcare sector are expanded into specific plans. The priorities and specificity of actions in healthcare plans were the distinguishing features between the two countries.CONCLUSIONS The common features of the healthcare plans in both the counties include violence against women, use of protocols, detection tasks, care and recovery for women, and professional self-care. Catalonia does not consider healthcare actions with aggressors. Costa Rica has a lower specificity in conceptualization and protocol patterns, as well as a lack of updates concerning health standards in Catalonia.

Effect of plug-filling, Testing velocity and temperature on the tensile strength of strap repairs on aluminium structures

In this work, an experimental study was performed on the influence of plug-filling, loading rate and temperature on the tensile strength of single-strap (SS) and double-strap (DS) repairs on aluminium structures. Whilst the main purpose of this work was to evaluate the feasibility of plug-filling for the strength improvement of these repairs, a parallel study was carried out to assess the sensitivity of the adhesive to external features that can affect the repairs performance, such as the rate of loading and environmental temperature. The experimental programme included repairs with different values of overlap length (L O = 10, 20 and 30 mm), and with and without plug-filling, whose results were interpreted in light of experimental evidence of the fracture modes and typical stress distributions for bonded repairs. The influence of the testing speed on the repairs strength was also addressed (considering 0.5, 5 and 25 mm/min). Accounting for the temperature effects, tests were carried out at room temperature (≈23°C), 50 and 80°C. This permitted a comparative evaluation of the adhesive tested below and above the glass transition temperature (T g), established by the manufacturer as 67°C. The combined influence of these two parameters on the repairs strength was also analysed. According to the results obtained from this work, design guidelines for repairing aluminium structures were

Trends in the use of antidepressants among older adults: Bambuí Project

OBJECTIVE To analyze the trends and factors associated with the antidepressant use among older adults. METHODS This population-based study evaluated older adults in 1997 (n = 351, baseline) and the survivors at the 15th follow-up year (n = 462, in 2012) among the aging cohort of Bambuí. The prevalence of antidepressant use was estimated, and the most commonly used antidepressants each year were identified. Prevalence ratios with 95% confidence intervals were estimated using Poisson regression with robust variance to investigate differences in the prevalence of use between 1997 and 2012. RESULTS The overall consumption of antidepressants (PR = 2.87, 95%CI 1.94;4.25) and of selective serotonin reuptake inhibitors (PR = 7.50, 95%CI 3.74;15.02) was significantly higher in 2012. However, no significant difference was observed in the use of tricyclic antidepressants between the two cohorts (PR = 0.89, 95%CI 0.49;1.62). In the 2012 cohort, antidepressant use was associated with females, increased age, increased income (≥ 4 minimum wages), self-assessment of health as reasonable, and attending ≥ 5 medical consultations in the last 12 months. CONCLUSIONS The increased consumption of antidepressants in the period due to increased use of selective serotonin reuptake inhibitors was consistent with results observed in international studies of different population groups and contexts. The positive correlation observed between antidepressant use and family income may be a warning of possible inequalities in access to mental health services.