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- Implementation of a non-Hertzian contact model for railway dynamic applicationPublication . Magalhães, Hugo; Marques, Filipe; Liu, Binbin; Antunes, Pedro; Pombo, João; Flores, Paulo; Ambrosio, Jorge; Piotrowski, Jerzy; Bruni, StefanoThe development of wheel–rail contact models is an active topic of railway research with the dual objective of improving the accuracy of multibody simulations and reducing its computational effort. This paper extends the online Hertzian contact model, proposed by Pombo et al. (Veh. Syst. Dyn. 45: 165–189, 2007) to propose a non-Hertzian contact model. The new methodology presented here includes the following steps: (i) search of the points of contact; (ii) identification of the undeformed distance function; (iii) evaluation of the contact patch; (iv) calculation of the normal and tangential contact forces; (v) application of the contact forces in the multibody vehicle model. Among several contact models available in the literature, this non-Hertzian contact approach uses the Kik–Piotrowski model for the normal contact force, while the tangential forces are obtained from the interpolation of the available Kalker Book of Tables for non-Hertzian (KBTNH) contact. With the purpose to demonstrate the proper implementation and selection of parameters that define this new model, several contact analysis and dynamic simulations are performed in which the wheel S1002 and the rail UIC50 are considered. First, the contact analyses that determine the contact condition of different wheel–rail interactions serve to assess the accuracy of the Hertzian and non-Hertzian models with respect to the software of reference CONTACT. Second, the Hertzian and non-Hertzian models are utilised to perform dynamic simulations of a wheelset, a bogie and a vehicle running in tangent and curved tracks. In short, this work provides, not only a complete description of the implementation of a non-Hertzian contact model in a multibody code, but also suggests for the proper selection of the parameters that promote better accuracy and optimal computational efficiency.
- Validação da Escala Physical Performance Test para a população geriátrica Portuguesa com demênciaPublication . Almeida, Ana; Antunes, Andreia; Ramos, Ines; Vicente, Joana; Gonçalves, Rui; Pedro, LuisaIntrodução: A demência é uma patologia neurodegenerativa caracterizada pela deterioração cognitiva associada ao declínio funcional. Em Portugal, existe escassez de instrumentos de medida para avaliar o desempenho físico destes pacientes. A escala Physical Performance Test (PPT) avalia a funcionalidade. O objetivo do estudo é validar as duas versões da escala - PPT-7 e 9 itens - para idosos com demência na população portuguesa. Material e Métodos: Efetuou-se um estudo transversal observacional. Dos 96 indivíduos avaliados, 60 cumpriram os critérios de inclusão: idade ≥ a 65 anos; diagnóstico de demência com avaliação através do Mini Mental State Examination entre 10 e 24 pontos. Cumpriram-se os procedimentos éticos da Declaração de Helsínquia. A recolha de dados realizou-se em oito instituições. Resultados: O alfa de Cronbach foi de 0,79 (avaliador 1 e 2) no PPT-9 itens e 0,69 (avaliador 1) e 0,70 (avaliador 2) no PPT-7 itens. Os valores de confiabilidade teste-reteste variam entre 0,65 e 0,72 (avaliador 1) e 0,52 e 0,91 (avaliador 2), exceto no item 3. Os valores de confiabilidade inter-avaliador superaram 0,95. Para o PPT-9 e PPT-7 itens, a correlação foi de 0,99. A convergência do PPT-9 itens com o IB é de 0,65 e do PPT-7 itens é de 0,64. Discussão: Os coeficientes do alfa de Cronbach revelaram bons níveis de confiabilidade. Ambas as versões apresentam boa reprodutibilidade, elevada concordância inter-observador e convergência moderada com o IB. Conclusão: A versão portuguesa do PPT-7 e 9 itens é fiável e válida para idosos com demência.
- A capacidade explicativa dos regressores à variação do MVA e remuneração dos administradores executivosPublication . Duarte, Bruno Miguel Guerreiro; Antunes, Marina GodinhoEste estudo aborda a gestão da pessoa, a teoria da agência e a maximização do valor para o acionista como o objetivo diretor da estratégia. O objeto de estudo foi circunscrito a grupos empresariais do setor energético que negoceiam ações no Psi 20 (o Grupo EDP, o Grupo REN, e o Grupo GALP Energia). A escolha resultou da política de remuneração aplicada integrar uma componente variável e decorreu no período 2008 a 2017, com o objetivo de garantir uma maior fiabilidade ao modelo econométrico. O objetivo foi segmentado em três modelos econométricos. O modelo A visou aferir se o Market Value Added (MVA) é explicado na globalidade pelos indicadores Economic Value Added (EVA), Total Share Return (TSR), Earnings Per Share (EPS) e Participações Qualificadas; o modelo B visou aferir se a Remuneração Variável é explicada na totalidade pelos indicadores EVA, TSR, e EPS; por último, o modelo C visou aferir se a Remuneração Variável é explicada na globalidade pelos indicadores EVA, TSR, EPS e MVA. Para recolha e tratamento dos dados foram usados procedimentos estatísticos, pesquisa bibliográfica e documental. Tratando-se de um estudo aplicado a grupos empresariais de um setor, a estratégia de investigação foi o estudo de caso. O modelo econométrico usado foi o Modelo de Regressão Linear Múltipla (MRLM). Os resultados das regressões e testes para um intervalo de confiança de 95% indicaram que o modelo A foi o único modelo onde as variáveis exógenas explicaram a variável endógena (𝐻𝑎: β𝑘 ≠ 0).
- A solid-state fluorescence sensor for nitroaromatics and nitroanilines based on a conjugated Calix[4]arene polymerPublication . Prata, José V.; Costa, Alexandra I.; Teixeira, CarlosA new conjugated polymer possessing calix[4]arene-oxacyclophane units wired-in-series by phenyleneethynylene linkers was synthesized by a Sonogashira-Hagihara cross-coupling method in high yield. The polymer was structurally characterized by FTIR and 1H/13C/HSQC NMR techniques, and its average Mn (38.5 kDa) retrieved from GPC analysis. The polymer is highly emissive (ΦF =0.55) and exhibits a longer-than-usual excited-state lifetime (1.80 ns) for a phenyleneethynylene type polymer. Similar photo physical properties (absorption and fluorescence emission) were observed in solution and insolid-state. This stems from the presence of bulky calixarene moieties along the polymer chains which prevent interchain staking and the formation of ground-state aggregates and/or non-emissive exciplexes, both deleterious to solid-state materials envisioned for fluorescence sensing applications. Moreover, the intrinsic molecular recognition capabilities of its two rigid inner cavities (calixarene and cyclophane sub-units), allied with the high three-dimensionality of the macromolecule that creates additional interstitial voids around the molecular receptors, can boost its sensory responses towards specific analytes. A high sensitive response was observed in the detection of nitroaromatics and nitroanilines in neat vapour phases by casted films of the polymer. The largest sensitivitieswereobtainedfor2,4-dinitrotoluene (a taggant for the explosive TNT;>85% of fluorescence quenching upon 1 min exposure) and ortho-nitroaniline (90% of emission reduction in 30s).The sensory responses attained in solid-state are discussed on the basis of the electron affinities of the analytes and their electrostatic interactions with polymer films.
- Application of the comet assay in human biomonitoring: an hCOMET perspectivePublication . Azqueta, Amaya; Ladeira, Carina; Giovannelli, Lisa; Boutet-Robinet, Elisa; Bonassi, Stefano; Neri, Monica; Gajski, Goran; Duthie, Susan; Del Bo’, Cristian; Riso, Patrizia; Koppen, Gudrun; Basaran, Nursen; Collins, Andrew; Møller, PeterThe comet assay is a well-accepted biomonitoring tool to examine the effect of dietary, lifestyle, environmental and occupational exposure on levels of DNA damage in human cells. With such a wide range of determinants for DNA damage levels, it becomes challenging to deal with confounding and certain factors are interrelated (e.g. poor nutritional intake may correlate with smoking status). This review describes the effect of intrinsic (i.e. sex, age, tobacco smoking, occupational exposure, and obesity) and extrinsic (season, environmental exposures, diet, physical activity, and alcohol consumption) factors on the level of DNA damage measured by the standard or enzyme-modified comet assay. Although each factor influences at least one comet assay endpoint, the collective evidence does not indicate single factors have a large impact. Thus, controlling for confounding may be necessary for a biomonitoring study, but none of the factors is strong enough to be regarded as a priori as a confounder. Controlling for confounding in the comet assay requires a case-by-case approach. Inter-laboratory variation in levels of DNA damage and to some extent also reproducibility in biomonitoring studies are issues that have haunted the users of the comet assay for years. Procedures to collect specimens, and their storage, are not standardized. Likewise, statistical issues related to both sample-size calculation (before sampling of specimens) and statistical analysis of the results vary between studies. This review gives guidance to statistical analysis of the typically complex exposure, co-variate, and effect relationships in human biomonitoring studies.
- Influence of laser surface nanotexturing on the friction behaviour of the silicon/sapphire systemPublication . Alves-Lopes, I.; Almeida, Amelia; Oliveira, Vítor; Vilar, R.The aim of the present work was to investigate the influence of textures consisting of Laser-Induced Periodic Surface Structures (LIPSS) on the friction coefficient of silicon under unlubricated conditions, using nanoscale friction tests. The tests were performed on <1 1 1> single crystal wafers of p-doped silicon. Surface texturing was performed by a direct writing technique, using 560 fs pulses of 1030 nm wavelength radiation and parameters allowing large areas with a uniform LIPSS texture to be obtained. The tribological tests were performed in air using a ball-on-flat nanotribometer with 3 mm diameter sapphire balls as counterbodies. The wear scars were analyzed by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The friction coefficient of polished Si remains approximately constant during the tests and is independent of the applied load, with values in the range 0.12-0.14. The morphology of the wear scars indicated that the predominant material removal mechanism is mild oxidative wear, independently of the testing conditions used, which explains the low values of the friction coefficient measured. The LIPSS texture leads to an increase of the friction coefficient, in particular in the perpendicular sliding direction. The friction coefficient increases with the applied load and is larger for the perpendicular sliding direction than for the parallel sliding direction, the difference increasing with increasing load. The morphology of the wear scars showed that the predominant wear regime remains oxidative wear, but significant contributions of plastic deformation and ploughing appear. This plastic deformation in Si, which is brittle at room temperature, shows that significant surface heating is being caused by the interaction of the asperities in motion and under load. This temperature increase also accelerates surface oxidation and increases the wear rate. Surface temperature calculations showed that the temperature increase is larger for the perpendicular sliding direction than for the parallel one, which explains the difference of friction coefficient observed in the two directions.
- Alimentação na demência avançada: documento de consenso da Sociedade Portuguesa de Medicina Interna e da Associação Portuguesa de Nutrição Entérica e ParentéricaPublication . Pessoa, Ana; Almeida, Paulo; Marinho, Ricardo Cleto; Duque, Sofia; Amaral, Teresa F.; Pinho, Joao; Santos, Mariana; Freire, Elga; Mendes, Lino; Santos, Lelita; Marinho, Anibal; Clara, João Gorjão; Araújo Correia, JoãoA demência é uma síndrome neurológica de agravamento progressivo, sem cura, cuja prevalência tem vindo a aumentar devido ao envelhecimento da população. Existe um grande desconhecimento entre profissionais de saúde e cuidadores relativamente à melhor abordagem da alimentação nos doentes com demência avançada. Dado não existirem recomendações nacionais acerca deste tema, foi elaborado um documento de consenso da Sociedade Portuguesa de Medicina Interna e da Associação Portuguesa de Nutrição Entérica e Parentérica que explicita as orientações existentes relativas à abordagem dos problemas alimentares nos doentes com demência avançada. A demência avançada é uma condição terminal em que deve ser privilegiado o conforto do doente, frequentemente acamado, incapaz de comunicar verbalmente e com dificuldade na alimentação. Nesta população, a literatura atual não recomenda o uso de alimentação por sonda (nasogástrica, nasojejunal, gastrostomia percutânea ou jejunostomia percutânea), que está associada a maior risco de infeção, maior utilização de meios de contenção e desenvolvimento de úlceras de decúbito. Como alternativa, recomenda-se a alimentação por via oral de acordo com a tolerância e vontade do doente (alimentação de conforto). Do ponto de vista ético e legal, é legítimo não proceder à artificialização da alimentação na fase terminal da demência caso este procedimento seja contrário aos valores da pessoa e não se objetivem benefícios. Esta decisão deve ser tomada após discussão multidisciplinar incluindo o doente (se possível), representante legal, cuidadores, família e equipa de profissionais de saúde envolvidos, elaborando um plano individual de cuidados que permita a tomada de decisões no melhor interesse do doente.
- Aspergillus spp. burden on filtering respiratory protective devices: is there an occupational health concern?Publication . Viegas, Carla; Dias, Marta; Almeida, Beatriz; Carolino, Elisabete; Gomes, Anita Quintal; Viegas, SusanaThere is scientific evidence that associates occupational exposure to fungi in the waste industry with health outcomes, being Aspergillus genera reported as the most prevalent. During Filtering Respiratory Protective Devices (FFR) use, humidity and temperature conditions provide favorable conditions for Aspergillus growth. The aim of this study was to characterize the Aspergillus burden retained by the FFR interior layer and exhalation valve. The sample consisted of 120 FFR and the correspondent interior layer and exhalation valves collected from different workstations from one waste sorting industry. The fungal content of exhalation valve and from the interior layer of the each FFR was extracted and inoculated on malt extract agar (MEA) supplemented with chloramphenicol (0.05%) and dichloran-glycerol agar (DG18). FFR extracts were also used for the molecular detection of Aspergillus sections Flavi and Fumigati. Valves presented Aspergillus spp. as the most prevalent genera on MEA media (44.4%), unlike what was observed in the FFR interior layer, where Aspergillus spp. was not the most prevalent genera (6.84% MEA; 5.2% DG18). Among the Aspergillus genera, section Fumigati was the one with the highest prevalence, both in exhalation valves (76.57% MEA; 87.24% DG18) and interior layer (75.81% MEA; 51.22% DG18). qPCR analysis successfully amplified DNA from the Aspergillus sections Flavi and Fumigati. Interior layers presented statistically significant differences showing a higher number of FFR contaminated with higher levels of Aspergillus in the workstations where workers contact directly with waste. This work, revealing strong fungal contamination of FFR used by workers at the waste industry, clearly indicates that future trials to test FFR protective efficacy and establishment of times for FFR replacement should be performed.
- Azole-resistance of mucorales in the waste sorting industryPublication . Caetano, Liliana AranhaIntroduction - Resistance to antibiotics is a well-known threat to public health. Fungal drug resistance is more recently being described as an emergent threat. The emergence of resistance to azoles among fungal species in the environmental challenges the management of severe fungal infections. Azole resistance could become a global public health threat with fungal spores able to disperse great distances on air currents. Considering the clinical relevance of Mucorales order, fungal exposure assessments should evaluate their prevalence and azole-resistance patterns. Aims - To determine Mucorales distribution in Personal Protective Equipment used by waste sorting workers in one waste sorting industry located in Lisbon district; to perform an azole-resistance screening using three medical azole drugs (itraconazole, voriconazole, and posaconazole) for the samples collected in the waste sorting industry.
- Characterization of a novel 3D-polymeric scaffold as a co-delivery systemPublication . Zegre, Miguel; Silveira, M.; Anjos, I.; Ribeiro, I. A.; Santos, C.; Caetano, Liliana Aranha; Gonçalves, L.; Bettercourt, A.Osteomyelitis is an inflammation of the bone caused by infection, leading to necrosis and tissue destruction. It can cause persistent morbidity and become a chronic disease, being one of the infectious diseases most difficult to manage. Staphylococcus aureus is the most usual causative pathogen in osteomyelitis, and bacterial infections are often complicated by concomitant fungal infections, Candida sp. being the most common. Co-encapsulation of drugs provides a convenient means for the administration of multiple drugs directed at commonly associated diseases. Three-dimensional scaffolds have become a crucial element of bone tissue engineering and regenerative medicine, are designed to provide an ideal environment for bone formation. Thus, this work aims to develop a new local drug-delivery system for the modulation of polymicrobial activity in bone infections, through the co-delivery of minocycline and voriconazole to the local site of infection, while fostering bone repair.