A New Method to Determine the Density and Water Absorption of Fine Recycled Aggregates

The construction industry keeps on demanding huge quantities of natural resources, mainly minerals for mortars and concrete production. The depletion of many quarries and environmental concerns about reducing the dumping of construction and demolition waste in quarries have led to an increase in the procuring and use of recycled aggregates from this type of waste. If they are to be incorporated in concrete and mortars it is essential to know their properties to guarantee the adequate performance of the end products, in both mechanical and durability-related terms. Existing regulated tests were developed for natural aggregates, however, and several problems arise when they are applied to recycled aggregates, especially fine recycled aggregates (FRA). This paper describes the main problems encountered with these tests and proposes an alternative method to determine the density and water absorption of FRA that removes them. The use of sodium hexametaphosphate solutions in the water absorption test has proven to improve its efficiency, minimizing cohesion between particles and helping to release entrained air.

Development and validation of a novel method for the analysis of chlorinated pesticides in soils using microwave-assisted extraction–headspace solid phase microextraction and gas chromatography–tandem mass spectrometry

A new procedure for determining eleven organochlorine pesticides in soils using microwave-assisted extraction (MAE) and headspace solid phase microextraction (HS-SPME) is described. The studied pesticides consisted of mirex, α- and γ-chlordane, p,p’-DDT, heptachlor, heptachlor epoxide isomer A, γ-hexachlorocyclohexane, dieldrin, endrin, aldrine and hexachlorobenzene. The HS-SPME was optimized for the most important parameters such as extraction time, sample volume and temperature. The present analytical procedure requires a reduced volume of organic solvents and avoids the need for extract clean-up steps. For optimized conditions the limits of detection for the method ranged from 0.02 to 3.6 ng/g, intermediate precision ranged from 14 to 36% (as CV%), and the recovery from 8 up to 51%. The proposed methodology can be used in the rapid screening of soil for the presence of the selected pesticides, and was applied to landfill soil samples.

Multiresidue method for the determination of organophosphorus pesticides in still wine and fortified wine using solid-phase microextraction and gas chromatography – Tandem mass spectrometry

A SPME-GC-MS/MS method for the determination of eight organophosphorus pesticides (azinphos-methyl, chlorpyriphos, chlorpyriphos-methyl, diazinon, fenitrothion, fenthion, malathion, and methidathion) in still and fortified wine was developed. The extraction procedure is simple, solvent free, and without any sample pretreatment. Limits of detection (LOD) and quantitation (LOQ) values in the range 0.1–14.3 lg/L and 0.2–43.3 lg/L, respectively, were obtained. The LOQ values are below the maximum residue levels (MRLs) established by European Regulation for grapes, with the exception of methidathion. Coefficients of correlation (R2) higher than 0.99 were obtained for the majority of the pesticides, in all different wines analyzed.

Quantification of endocrine disruptors and pesticides in water by gas chromatography–tandem mass spectrometry. Method validation using weighted linear regression schemes

Amulti-residue methodology based on a solid phase extraction followed by gas chromatography–tandem mass spectrometry was developed for trace analysis of 32 compounds in water matrices, including estrogens and several pesticides from different chemical families, some of them with endocrine disrupting properties. Matrix standard calibration solutions were prepared by adding known amounts of the analytes to a residue-free sample to compensate matrix-induced chromatographic response enhancement observed for certain pesticides. Validation was done mainly according to the International Conference on Harmonisation recommendations, as well as some European and American validation guidelines with specifications for pesticides analysis and/or GC–MS methodology. As the assumption of homoscedasticity was not met for analytical data, weighted least squares linear regression procedure was applied as a simple and effective way to counteract the greater influence of the greater concentrations on the fitted regression line, improving accuracy at the lower end of the calibration curve. The method was considered validated for 31 compounds after consistent evaluation of the key analytical parameters: specificity, linearity, limit of detection and quantification, range, precision, accuracy, extraction efficiency, stability and robustness.

Contributos para a compreensão das dimensões e características do Capital Intelectual valorizadas por uma Empresa líder no Sector dos Seguros em Portugal

Mestrado em Gestão e Empreendedorismo

Flow-injection potentiometric method for the routine determination of chloride: application to bread analysis

Bread is consumed worldwide by man, thus contributing to the regular ingestion of certain inorganic species such as chloride. It controls the blood pressure if associated to a sodium intake and may increase the incidence of stomach ulcer. Its routine control should thus be established by means of quick and low cost procedures. This work reports a double- channel flow injection analysis (FIA) system with a new chloride sensor for the analysis of bread. All solutions are prepared in water and necessary ionic strength adjustments are made on-line. The body of the indicating electrode is made from a silver needle of 0.8 mm i.d. with an external layer of silver chloride. These devices were constructed with different lengths. Electrodes of 1.0 to 3.0 cm presented better analytical performance. The calibration curves under optimum conditions displayed Nernstian behaviour, with average slopes of 56 mV decade-1, with sampling rates of 60 samples h-1. The method was applied to analyze several kinds of bread, namely pão de trigo, pão integral, pão de centeio, pão de mistura, broa de milho, pão sem sal, pão meio sal, pão-de-leite, and pão de água. The accuracy and precision of the potentiometric method were ascertained by comparison to a spectrophotometric method of continuous segmented flow. These methods were validated against ion-chromatography procedures.

A cobertura jornalística da Capital Europeia da Cultura: Porto 2001

A apresentação pretende ilustrar a cobertura que a imprensa nacional realizou ao acontecimento Porto Capital Europeia da Cultura em 2001. A análise contempla os jornais Público, Diário de Notícias, Jornal de Notícias, Correio da Manhã e Expresso e a revista Visão no período anterior ao do evento (ano de 2000), durante e após, para se conseguir definir as etapas que marcaram os diferentes momentos do acontecimento, os padrões de atuação, o tipo de planeamento e as especificidades ao nível da programação. Na génese do projeto das Capitais Europeias da Cultura, da autoria da ministra da cultura grega e que aconteceu pela primeira vez em Atenas em 1985, estava a ideia de eleger, de ano para ano, uma cidade em que se apresentassem novos paradigmas culturais. Lisboa foi a primeira cidade portuguesa a acolher, em 1994, a iniciativa, seguiu-se o Porto em 2001 e em 2012 é a vez de Guimarães. Protagonista da descentralização cultural, é um modelo que tem permitido o financiamento de obras públicas (lembre-se a Casa da Música no Porto), o restauro de património e a promoção das cidades em termos turísticos. No entanto, espera-se ver questionado o seu papel enquanto lugares de inovação quer em termos de políticas culturais, quer em termos de produção e inovação artística. No artigo “Capitais europeias da cultura: que fazer com elas?”, publicado no suplemento Ípsilon do jornal Público de 1 de Abril de 2011, António Pinto Ribeiro refere a insustentabilidade das cidades após o ano de capital cultural, “as expectativas goradas da maioria dos seus cidadãos e a retração no apoio à produção que acontece sempre no período pós-capital”. Espera-se através desta análise conseguir demarcar os momentos que ganharam visibilidade e enformaram o acontecimento para, de forma crítica, se poder refletir sobre o papel da imprensa na divulgação e promoção de eventos de cariz cultural.

Portuguese newspapers’ front-page and the coverage of European Cultural Capital: Porto 2001 and Guimarães 2012

Portugal hosted in the last thirteen years, two editions of the event European Cultural Capital; this paper intends to illustrate the coverage that Portuguese newspapers (daily newspapers Público, Diário de Notícias, Correio da Manhã and Jornal de Notícias, a weekly newsmagazine Visão and a weekly newspaper Expresso) made, through referrals in front-page and respective developments within the editions, to each of the events and that allows us to define the main moments that marked each of them, patterns of action, the major players, planning and programming types. The European Cultural Capital project elects, from year to year, cities of different EU member states with the main goal of “contributing to bring together the Europe´s people" (words of Mélina Mercouri, Greek Minister of Culture who, in 1985, proposed the launch of this initiative) and encouraging the elected urban space to present new cultural paradigms. In the genesis of this model is the cultural decentralization’s vector, a possibility to medium-sized cities of funding public works, restoring heritage and promoting themselves in touristic terms, of giving visibility to cities away from cultural and creative industries’ major distribution centers. A crucial factor to achieve this goal is media coverage. This paper outline the information that the Portuguese press ran over the two years that elapsed the latest editions of the European Cultural Capital in Portugal, namely that media coverage have deviated from the disclosure of the events’ schedule to suggest itineraries of visit and little or not even question the role that cities, promoting such initiatives, have as places of innovation in terms of cultural policies, artistic production and innovation, in urban and environmental regeneration, in economic revitalization, in training and creating new artists and new audiences and in boosting the confidence of local communities. The content analysis performed to articles shows how press is essential to the promotion of cities as cultural/touristic destinations as it stimulates consumption among residents and attracts visitors, with the possible dire consequence of turning the cultural journalist into an agent of touristic instead of cultural promotion.

O papel do capital psicológico no bem-estar subjetivo

A perspetiva positiva tem ganho crescente importância nas tentativas de compreensão de variáveis e processos organizacionais. Neste âmbito destaca-se o comportamento organizacional positivo e o seu constructo central, o capital psicológico, entendido como o estado individual de desenvolvimento de um conjunto de capacidades psicológicas, em que se contam a auto-eficácia, o otimismo, a esperança e a resiliência. A evidência empírica sugere que este fator psicológico de positividade produz efeitos benéficos nas atitudes, comportamentos e desempenho dos colaboradores organizacionais (e.g., Avey, Luthans, & Youssef, 2010), mas também em fatores relacionados com a saúde e bem-estar. A presente meta-análise examina as relações entre capital psicológico, bem-estar subjetivo no contexto laboral e diversos fatores que concorrem para este bem-estar (e.g., stress no trabalho, esgotamento, exaustão emocional). O conjunto de estudos usado nesta revisão quantitativa foi obtido através de diversas técnicas padrão de pesquisa de literatura. Foi realizada uma pesquisa exaustiva em bases de dados especializadas, complementada com pesquisas ancestrais e de descendência. Diversos investigadores foram contactados com o fito de obter investigações não publicadas. A partir do acervo de estudos obtido foram definidos critérios de inclusão e exclusão para a seleção de estudos a considerar na presente meta-análise. Os resultados revelam que existe uma relação positiva entre capital psicológico e bem-estar subjetivo, sendo concomitantemente identificadas relações negativas entre este recurso psicológico e fatores como o stresse, o esgotamento e a exaustão emocional. As implicações destes resultados são discutidas e são avançadas diversas sugestões de investigação futura.

O papel do capital psicológico no bem-estar subjetivo

A perspetiva positiva tem ganho crescente importância nas tentativas de compreensão de variáveis e processos organizacionais. Neste âmbito destaca-se o comportamento organizacional positivo e o seu constructo central, o capital psicológico, entendido como o estado individual de desenvolvimento de um conjunto de capacidades psicológicas, em que se contam a auto-eficácia, o otimismo, a esperança e a resiliência. A evidência empírica sugere que este fator psicológico de positividade produz efeitos benéficos nas atitudes, comportamentos e desempenho dos colaboradores organizacionais (e.g., Avey, Luthans, & Youssef, 2010), mas também em fatores relacionados com a saúde e bem-estar. A presente meta-análise examina as relações entre capital psicológico, bem-estar subjetivo no contexto laboral e diversos fatores que concorrem para este bem-estar (e.g., stress no trabalho, esgotamento, exaustão emocional). O conjunto de estudos usado nesta revisão quantitativa foi obtido através de diversas técnicas padrão de pesquisa de literatura. Foi realizada uma pesquisa exaustiva em bases de dados especializadas, complementada com pesquisas ancestrais e de descendência. Diversos investigadores foram contactados com o fito de obter investigações não publicadas. A partir do acervo de estudos obtido foram definidos critérios de inclusão e exclusão para a seleção de estudos a considerar na presente meta-análise. Os resultados revelam que existe uma relação positiva entre capital psicológico e bem-estar subjetivo, sendo concomitantemente identificadas relações negativas entre este recurso psicológico e fatores como o stresse, o esgotamento e a exaustão emocional. As implicações destes resultados são discutidas e são avançadas diversas sugestões de investigação futura.

Development of a simple analytical method for the simultaneousdetermination of paracetamol, paracetamol-glucuronide andp-aminophenol in river water

Paracetamol is among the most worldwide consumed pharmaceuticals. Although its occurrence in the environment is well documented, data about the presence of its metabolites and transformation products is very scarce. The present work describes the development of an analytical method for the simultaneous determination of paracetamol, its principal metabolite (paracetamol-glucuronide) and its main transformation product (p-aminophenol) based on solid phase extraction (SPE) and high performance liquid chromatography coupled to diode array detection (HPLC-DAD). The method was applied to analysis of river waters, showing to be suitable to be used in routine analysis. Different SPE sorbents were compared and the use of two Oasis WAX cartridges in tandem proved to be the most adequate approach for sample clean up and pre-concentration. Under optimized conditions, limits of detection in the range 40–67 ng/L were obtained, as well as mean recoveries between 60 and 110% with relative standard deviations (RSD) below 6%. Finally, the developed SPE-HPLC/DAD method was successfully applied to the analysis of the selected compounds in samples from seven rivers located in the north of Portugal. Nevertheless all the compounds were detected, it was the first time that paracetamol-glucuronide was found in river water at concentrations up to 3.57 μg/L.

Tensile behaviour of a structural adhesive at high temperatures by the extended finite element method

Component joining is typically performed by welding, fastening, or adhesive-bonding. For bonded aerospace applications, adhesives must withstand high-temperatures (200°C or above, depending on the application), which implies their mechanical characterization under identical conditions. The extended finite element method (XFEM) is an enhancement of the finite element method (FEM) that can be used for the strength prediction of bonded structures. This work proposes and validates damage laws for a thin layer of an epoxy adhesive at room temperature (RT), 100, 150, and 200°C using the XFEM. The fracture toughness (G Ic ) and maximum load ( ); in pure tensile loading were defined by testing double-cantilever beam (DCB) and bulk tensile specimens, respectively, which permitted building the damage laws for each temperature. The bulk test results revealed that decreased gradually with the temperature. On the other hand, the value of G Ic of the adhesive, extracted from the DCB data, was shown to be relatively insensitive to temperature up to the glass transition temperature (T g ), while above T g (at 200°C) a great reduction took place. The output of the DCB numerical simulations for the various temperatures showed a good agreement with the experimental results, which validated the obtained data for strength prediction of bonded joints in tension. By the obtained results, the XFEM proved to be an alternative for the accurate strength prediction of bonded structures.

Estágio curricular na "Empreitada da 3ª fase de reparação do Caneiro de Alcântara"

Trabalho de Relatório de Estágio para obtenção do grau de Mestre em Engenharia Civil na Área de Especialização de Edificações

Analysis of temperature time-series: embedding dynamics into the MDS method

Global warming and the associated climate changes are being the subject of intensive research due to their major impact on social, economic and health aspects of the human life. Surface temperature time-series characterise Earth as a slow dynamics spatiotemporal system, evidencing long memory behaviour, typical of fractional order systems. Such phenomena are difficult to model and analyse, demanding for alternative approaches. This paper studies the complex correlations between global temperature time-series using the Multidimensional scaling (MDS) approach. MDS provides a graphical representation of the pattern of climatic similarities between regions around the globe. The similarities are quantified through two mathematical indices that correlate the monthly average temperatures observed in meteorological stations, over a given period of time. Furthermore, time dynamics is analysed by performing the MDS analysis over slices sampling the time series. MDS generates maps describing the stations’ locus in the perspective that, if they are perceived to be similar to each other, then they are placed on the map forming clusters. We show that MDS provides an intuitive and useful visual representation of the complex relationships that are present among temperature time-series, which are not perceived on traditional geographic maps. Moreover, MDS avoids sensitivity to the irregular distribution density of the meteorological stations.