Analysis of polycyclic aromatic hydrocarbons in atmospheric particulate samples by microwaveassisted extraction and liquid chromatography

A methodology based on microwave-assisted extraction (MAE) and LC with fluorescence detection (FLD) was investigated for the efficient determination of 15 polycyclic aromatic hydrocarbons (PAHs) regarded as priority pollutants by the US Environmental Protection Agency and dibenzo(a,l)pyrene in atmospheric particulate samples. PAHs were successfully extracted from real outdoor particulate matter (PM) samples with recoveries ranging from 81.4±8.8 to 112.0±1.1%, for all the compounds except for naphthalene (62.3±18.0%) and anthracene (67.3±5.7%), under the optimum MAE conditions (30.0 mL of ACN for 20 min at 110ºC). No clean-up steps were necessary prior to LC analysis. LOQs ranging from 0.0054 ng/m3 for benzo( a)anthracene to 0.089 ng/m3 for naphthalene were reached. The validated MAE methodology was applied to the determination of PAHs from a set of real world PM samples collected in Oporto (north of Portugal). The sum of particulate-bound PAHs in outdoor PM ranged from 2.5 and 28 ng/m3.

Interlimb relation during the double support phase of gait: an electromyographic, mechanical and energy based analysis

The purpose of this study is to analyse the interlimb relation and the influence of mechanical energy on metabolic energy expenditure during gait. In total, 22 subjects were monitored as to electromyographic activity, ground reaction forces and VO2 consumption (metabolic power) during gait. The results demonstrate a moderate negative correlation between the activity of tibialis anterior, biceps femoris and vastus medialis of the trailing limb during the transition between midstance and double support and that of the leading limb during double support for the same muscles, and between these and gastrocnemius medialis and soleus of the trailing limb during double support. Trailing limb soleus during the transition between mid-stance and double support was positively correlated to leading limb tibialis anterior, vastus medialis and biceps femoris during double support. Also, the trailing limb centre of mass mechanical work was strongly influenced by the leading limbs, although only the mechanical power related to forward progression of both limbs was correlated to metabolic power. These findings demonstrate a consistent interlimb relation in terms of electromyographic activity and centre of mass mechanical work, being the relations occurred in the plane of forward progression the more important to gait energy expenditure.

Aplicação do Failure Mode and Effect Analysis (FMEA) na demolição, movimento de terras e execução da estrutura em edifícios

Mestrado em Engenharia Civil - Ramo Tecnologia e gestão das Construções

Damage analysis of carbon/epoxy plates after drilling

Drilling of composites plates normally uses traditional techniques but damage risk is high. NDT use is important. Damage in a carbon/epoxy plate is evaluated by enhanced X-rays. Four different drills are used. The images are analysed using Computational Vision techniques. Surface roughness is compared. Results suggest strategies for delamination reduction.

Electrical skin phenomena: a fractional calculus analysis

The internal impedance of a wire is the function of the frequency. In a conductor, where the conductivity is sufficiently high, the displacement current density can be neglected. In this case, the conduction current density is given by the product of the electric field and the conductance. One of the aspects of the high-frequency effects is the skin effect (SE). The fundamental problem with SE is it attenuates the higher frequency components of a signal.

Aplicação da técnica Análise do Valor (AV) a um determinado porduto/serviço

Mestrado em Engenharia Mecânica - Gestão de Processos e Operações

Negotiation mechanism for self-organized scheduling system with collective intelligence

Current Manufacturing Systems challenges due to international economic crisis, market globalization and e-business trends, incites the development of intelligent systems to support decision making, which allows managers to concentrate on high-level tasks management while improving decision response and effectiveness towards manufacturing agility. This paper presents a novel negotiation mechanism for dynamic scheduling based on social and collective intelligence. Under the proposed negotiation mechanism, agents must interact and collaborate in order to improve the global schedule. Swarm Intelligence (SI) is considered a general aggregation term for several computational techniques, which use ideas and inspiration from the social behaviors of insects and other biological systems. This work is primarily concerned with negotiation, where multiple self-interested agents can reach agreement over the exchange of operations on competitive resources. Experimental analysis was performed in order to validate the influence of negotiation mechanism in the system performance and the SI technique. Empirical results and statistical evidence illustrate that the negotiation mechanism influence significantly the overall system performance and the effectiveness of Artificial Bee Colony for makespan minimization and on the machine occupation maximization.

Electrochemical immunosensor for the analysis of the breast cancer biomarker HER2 ECD

Human epidermal growth factor receptor 2 (HER2) is a breast cancer biomarker that plays a major role in promoting breast cancer cell proliferation and malignant growth. The extracellular domain (ECD) of HER2 can be shed into the blood stream and its concentration is measurable in the serum fraction of blood. In this work an electrochemical immunosensor for the analysis of HER2 ECD in human serum samples was developed. To achieve this goal a screen-printed carbon electrode, modified with gold nanoparticles, was used as transducer surface. A sandwich immunoassay, using two monoclonal antibodies, was employed and the detection of the antibody–antigen interaction was performed through the analysis of an enzymatic reaction product by linear sweep voltammetry. Using the optimized experimental conditions the calibration curve (ip vs. log[HER2 ECD]) was established between 15 and 100 ng/mL and a limit of detection (LOD) of 4.4 ng/mL was achieved. These results indicate that the developed immunosensor could be a promising tool in breast cancer diagnostics, patient follow-up and monitoring of metastatic breast cancer since it allows quantification in a useful concentration range and has an LOD below the established cut-off value (15 ng/mL).

Association between dairy product intake and abdominal obesity in Azorean adolescents

BACKGROUND: Some studies have reported an inverse association between dairy product (DP) consumption and weight or fat mass loss. OBJECTIVES: The objective of our study was to assess the association between DP intake and abdominal obesity (AO) among Azorean adolescents. SUBJECTS/METHODS: This study was a cross-sectional analysis. A total of 903 adolescents (370 boys) aged 15--16 years was evaluated. Anthropometric measurements were collected (weight, height and waist circumference (WC)) and McCarthy’s cut-points were used to categorize WC. AO was defined when WC was X90th percentile. Adolescent food intake was assessed using a self-administered semiquantitative food frequency questionnaire and DP intake was categorized in o2 and X2 servings/day. Data were analyzed separately for girls and boys, and logistical regression was used to estimate the association between DPs and AO adjusting for potential confounders. RESULTS: The prevalence of AO was 54.9% (boys: 32.1% and girls: 70.7%, Po0.001). For boys and girls, DP consumption was 2.3±1.9 and 2.1±1.6 servings/day (P¼0.185), respectively. In both genders, the proportion of adolescents with WC o90th percentile was higher among individuals who reported a dairy intake of X2 servings/day compared with those with an intake o2 servings/day (boys: 71% vs 65% and girls: 36% vs 24%, Po0.05). After adjustments for confounders, two or more DP servings per day were a negative predictor of AO (odds ratio, 0.217; 95% confidence interval, 0.075 -- 0.633) only in boys. CONCLUSION: We found a protective association between DP intake and AO only in boys.

Análise da eficácia da aplicação da Metodologia FMEA do Processo: Caso de estudo numa empresa certificada

Num mercado globalizado, a procura contínua de vantagens competitivas é um fator crucial para o sucesso das organizações. A melhoria contínua dos processos é uma abordagem usual, uma vez que os resultados destas melhorias vão se traduzir diretamente na qualidade dos produtos. Neste contexto, a metodologia Failure Mode Effect Analysis (FMEA) é muito utilizada, especialmente pelas suas características proactivas, que permitem a identificação e a prevenção de erros do processo. Assim, quanto mais eficaz for a aplicação desta ferramenta, mais benefícios terá a organização. Assim, quando é utilizado com eficácia, o FMEA de Processo, além de ser um método poderoso na análise do processo, permite a melhoria contínua e a redução dos custos [1] . Este trabalho de dissertação teve como objetivo avaliar a eficácia da utilização da ferramenta do FMEA de processo numa organização certificada segundo a norma ISO/TS16949. A metodologia proposta passa pela análise de dados reais, ou seja, comparar as falhas verificadas no mercado com as falhas que tinham sido identificadas no FMEA. Assim, ao analisar o nível de falhas identificadas e não identificadas durante o FMEA e a projeção dessas falhas no mercado, consegue-se determinar se o FMEA foi mais ou menos eficaz, e ainda, identificar fatores que condicionam a melhor utilização da mesma. Este estudo, está organizado em três fases, a primeira apresenta a metodologia proposta , com a definição de um fluxograma do processo de avaliação e as métricas usadas, a segunda fase a aplicação do modelo proposto a dois casos de estudo, e uma última fase, que consiste na análise comparativa, individual e global, que visa, além de comparar esultados, identificar pontos fracos durante a execução do FMEA. Os resultados do caso de estudo indicam que a ferramenta do FMEA tem sido usada com eficácia, pois consegue-se identificar uma quantidade significativa de falhas potenciais e evitá-las. No entanto, existem ainda falhas que não foram identificadas no FMEA e que apareceram no cliente, e ainda, algumas falhas que foram identificadas e apareceram no cliente. As falhas traduzem-se em má qualidade e custos para o negócio, pelo que são propostas ações de melhoria. Pode-se concluir que uma boa utilização do FMEA pode ser um fator importante para a qualidade do serviço ao cliente, e ainda, com impacto dos custos.

Electrical Skin Phenomena: A Fractional Calculus Analysis

The internal impedance of a wire is the function of the frequency. In a conductor, where the conductivity is sufficiently high, the displacement current density can be neglected. In this case, the conduction current density is given by the product of the electric field and the conductance. One of the aspects the high-frequency effects is the skin effect (SE). The fundamental problem with SE is it attenuates the higher frequency components of a signal. The SE was first verified by Kelvin in 1887. Since then many researchers developed work on the subject and presently a comprehensive physical model, based on the Maxwell equations, is well established. The Maxwell formalism plays a fundamental role in the electromagnetic theory. These equations lead to the derivation of mathematical descriptions useful in many applications in physics and engineering. Maxwell is generally regarded as the 19th century scientist who had the greatest influence on 20th century physics, making contributions to the fundamental models of nature. The Maxwell equations involve only the integer-order calculus and, therefore, it is natural that the resulting classical models adopted in electrical engineering reflect this perspective. Recently, a closer look of some phenomas present in electrical systems and the motivation towards the development of precise models, seem to point out the requirement for a fractional calculus approach. Bearing these ideas in mind, in this study we address the SE and we re-evaluate the results demonstrating its fractional-order nature.

Aquisição e Processamento de Imagens de Microscopia em Balística Forense

As novas tecnologias aplicadas ao processamento de imagem e reconhecimento de padrões têm sido alvo de um grande progresso nas últimas décadas. A sua aplicação é transversal a diversas áreas da ciência, nomeadamente a área da balística forense. O estudo de evidências (invólucros e projeteis) encontradas numa cena de crime, recorrendo a técnicas de processamento e análise de imagem, é pertinente pelo facto de, aquando do disparo, as armas de fogo imprimirem marcas únicas nos invólucros e projéteis deflagrados, permitindo relacionar evidências deflagradas pela mesma arma. A comparação manual de evidências encontradas numa cena de crime com evidências presentes numa base de dados, em termos de parâmetros visuais, constitui uma abordagem demorada. No âmbito deste trabalho pretendeu-se desenvolver técnicas automáticas de processamento e análise de imagens de evidências, obtidas através do microscópio ótico de comparação, tendo por base algoritmos computacionais. Estes foram desenvolvidos com recurso a pacotes de bibliotecas e a ferramentas open-source. Para a aquisição das imagens de evidências balísticas foram definidas quatro modalidades de aquisição: modalidade Planar, Multifocus, Microscan e Multiscan. As imagens obtidas foram aplicados algoritmos de processamento especialmente desenvolvidos para o efeito. A aplicação dos algoritmos de processamento permite a segmentação de imagem, a extração de características e o alinhamento de imagem. Este último tem como finalidade correlacionar as evidências e obter um valor quantitativo (métrica), indicando o quão similar essas evidências são. Com base no trabalho desenvolvido e nos resultados obtidos, foram definidos protocolos de aquisição de imagens de microscopia, que possibilitam a aquisição de imagens das regiões passiveis de serem estudadas, assim como algoritmos que permitem automatizar o posterior processo de alinhamento de imagens de evidências, constituindo uma vantagem em relação ao processo de comparação manual.

Delineating environmental groundwater vulnerability and protection zones mapping in fractured rock masses

Hard‐rock watersheds commonly exhibit complex geological bedrock and morphological features. Hydromineral resources have relevant economic value for the thermal spas industry. The present study aims to develop a groundwater vulnerability approach in Caldas da Cavaca hydromineral system (Aguiar da Beira, Central Portugal) which has a thermal tradition that dates back to the late 19th century, and contribute to a better understanding of the hydrogeological conceptual site model. In this work different layers were overlaid, generating several thematic maps to arrive at an integrated framework of several key‐sectors in Caldas da Cavaca site. Thus, to accomplish a comprehensive analysis and conceptualization of the site, a multi‐technical approach was used, such as, field and laboratory techniques, where several data was collected, like geotectonics, hydrology and hydrogeology, hydrogeomorphology, hydrogeophysical and hydrogeomechanical zoning aiming the application of the so‐called DISCO method. All these techniques were successfully performed and a groundwater vulnerability to contamination assessment, based on GOD‐S, DRASTIC‐Fm, SINTACS, SI and DISCO indexes methodology, was delineated. Geographical Information Systems (GIS) technology was on the basis to organise and integrate the geodatabases and to produce all the thematic maps. This multi‐technical approach highlights the importance of groundwater vulnerability to contamination mapping as a tool to support hydrogeological conceptualisation, contributing to better decision‐making of water resources management and sustainability.