Browsing by Issue Date, starting with "2019-02"
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- A co-simulation approach to the wheel–rail contact with flexible railway trackPublication . Antunes, Pedro; Magalhães, Hugo; Ambrosio, Jorge; Pombo, João; Neves Costa, JoãoThe standard approach to railway vehicle dynamic analysis includes running the vehicle multibody models in rigid railway tracks. The wheel–rail contact, independently of the rolling contact model used, is either handled online or via lookup tables. This traditional approach disregards the coupling effects between the railway vehicle dynamics and the railway track flexibility. In this work the assumption of rigidity of the railway track is relaxed and a finite element model of the complete track, i.e. rails, pads, sleepers, ballast and infrastructure, is used to represent the track geometry and flexibility. A rail–wheel contact model that evaluates the contact conditions and forces is used online. The dynamics of the railway vehicle is described using a multibody methodology while the track structure is described using a finite element approach. Due to the fact that not only the multibody and the finite element dynamic analysis use different integration algorithms but also because the vehicle and track models are simulated in different, codes a co-simulation procedure is proposed and demonstrated to address the coupled dynamics of the system. This approach allows us to analyze the vehicle dynamics in a flexible track with a general geometry modeled with finite elements, i.e. including curvature, cant, vertical slopes and irregularities, which is another novel contribution. The methodology proposed in this work is demonstrated in an application, in which the railway vehicle–track interaction shows the influence of the vehicle dynamics on the track dynamics and vice versa.
- Evaluation of the amount of nanoparticles emitted in LASER additive manufacture/weldingPublication . Gomes, J. F.; Miranda, R.; Oliveira, J. P.; Esteves, H. M.; Albuquerque, PaulaObjectives: The objective of this study was the evaluation of the professional exposure to nanoparticles during tasks performed in workstations for production of metallic parts by laser welding additive manufacturing. Materials and methods: The study was developed in an installed additive manufacturing machine, having controlled temperature and humidity in an industrial unit where metal parts were being produced using stainless steel powders of granulometry of 10 to 35 μm. Results and discussion: Monitoring of airborne nanoparticles emission was made using adequate equipment, which showed considerable number of nanoparticles over the baseline, having the same composition as the steel powder used. Conclusion: It is concluded that the values of professional exposure to nanoparticles are high in these workstations and that the nanoparticles to which the workers are exposed are small in size (around 15 nm), thus having a strong capacity for alveolar penetration and, consequently, with a strong possibility of passing to the bloodstream, accumulating in the body.
- Thermal nature of mantle upwellings below the ibero-western Maghreb region inferred from teleseismic tomographyPublication . Civiero, Chiara; Custodio, Susana; Rawlinson, Nicholas; Strak, Vincent; Silveira, Graça; Arroucau, Pierre; Corela, CarlosIndependent models of P wave and S wave velocity anomalies in the mantle derived from seismic tomography help to distinguish thermal signatures from those of partial melt, volatiles, and compositional variations. Here we use seismic data from SW Europe and NW Africa, spanning the region between the Pyrenees and the Canaries, in order to obtain a new S-SKS relative arrival-time tomographic model of the upper mantle below Iberia, Western Morocco, and the Canaries. Similar to previous P wave tomographic results, the S wave model provides evidence for (1) subvertical upper-mantle low-velocity structures below the Canaries, Atlas Ranges, and Gibraltar Arc, which are interpreted as mantle upwellings fed by a common lower-mantle source below the Canaries; and (2) two low-velocity anomalies below the eastern Rif and Betics that we interpret as the result of the interaction between quasi-toroidal mantle flow induced by the Gibraltar slab and the mantle upwelling behind it. The analysis of teleseismic P wave and S wave arrival-time residuals and the conversion of the low-velocity anomalies to temperature variations suggest that the upwellings in the upper mantle below the Canaries, Atlas Ranges, and Gibraltar Arc system may be solely thermal in nature, with temperature excesses in the range similar to 100-350 degrees C. Our results also indicate that local partial melting can be present at lithospheric depths, especially below the Atlas Ranges. The locations of thermal mantle upwellings are in good agreement with those of thinned lithosphere, moderate to high heat-flow measurements, and recent magmatic activity at the surface.
- O modelo de activity-based quality costs (ABQC): aplicação e análise no Instituto Politécnico de Lisboa (IPL)Publication . Cabo, Joana Simões do; Justino, Maria do RosárioO objetivo fulcral da presente investigação é a execução de uma proposta de aplicação de um modelo de gestão de qualidade, designado Activity-Based Quality Costs (ABQC), que surgiu no início da década de 90 do século passado, como resultado do trabalho do professor Joaquín Texeira Quirós. As organizações para, atualmente, encontrarem fatores diversificadores que lhes garantam competitividade em mercados cada vez mais concorrenciais e globais têm de definir estratégias que lhe proporcionem destaque e preferência no processo de criação de valor. É, então, necessário, mais do que nunca, a criação de uma estratégia de gestão apoiada na manutenção de um Sistema de Gestão de Qualidade (SGQ), como solução para o alcance de vantagens competitivas. Deste modo, a qualidade, como um dos critérios preponderantes nas estratégias de negócio, tem vindo a ganhar particular relevância, moldando práticas e políticas organizacionais. Neste âmbito, o referido modelo permite medir e justificar as estratégias no campo da gestão da qualidade, sendo que os benefícios que, eventualmente, se podem vir a obter com a sua aplicação estendem-se a todas as áreas organizacionais. A parte teórica desta dissertação pretende enquadrar o leitor no tema da qualidade e abordar a sua envolvência atual. Para expor esta problemática, será ainda desenvolvido, na parte prática, um estudo de caso focado numa Instituição de Ensino Superior (IES) certificada à luz da ISO 9001, nomeadamente, o Instituto Politécnico de Lisboa (IPL). Pelos resultados obtidos, conclui-se que a implementação de um modelo de gestão de qualidade potencia a competitividade e estimula a criação de valor empresarial.
- Influence of functional foot orthoses on the plantar pressure of 5 handball athletes: analysis using a novel system during 3 athletic tasksPublication . Esteves, João; Luz, André; Fidalgo, Rodrigo; Briôa, Mário; Matos, José PedroIn sports involving high impact forces, like handball, the intense effort alongside the set of repetitive motions is connected with an increase on forefoot plantar pressure consequently increasing injury probability. As a preventive measure, the use of functional foot orthoses (FFO) is recommended for plantar pressure redistribution. The goal of this study was to determine functional foot orthoses influence on forefoot plantar pressure, during three athletic movements. Two tests were performed in five athletes, one with the standard insole and the other with a functional foot.
- Mesoporous nanosilica-supported polyoxomolybdate as catalysts for sustainable desulfurizationPublication . Mirante, Fátima; Gomes, Neide; Branco, Luis; Cunha-Silva, Luís; Almeida, Pedro L.; Pillinger, Martyn; Gago, S.; Granadeiro, Carlos; Balula, SaleteMesoporous silica nanoparticles (MSNs) strategically functionalized were used to immobilize a homogeneous polyoxomolybdate catalyst [PMo12O40](3-) (PMo12), active but unstable. The PMo12@TBA-MSN composite (where TBA refers to surface-tethered tributylammonium groups) conferred high stability to the polyoxomolybdate catalytic center and displayed an increase in efficiency for the oxidative desulfurization (ECODS) of a diesel simulant under sustainable conditions (using H2O2 as oxidant and an ionic liquid, [BMIM]PF6, as solvent). Continuous reuse of the catalyst and ionic liquid solvent in consecutive ECODS cycles was successfully performed, avoiding the production of residual wastes. The performance of the PMo12@TBA-MSN catalyst improved upon its reuse, leading to complete desulfurization of a multicomponent model diesel containing benzothiophene derivatives after just 1 h of the catalytic stage of the process. The robust nature of the supported catalyst was indicated by characterization of the recovered solid which showed retention of the structural and chemical integrities.
- An optimization strategy for customized radiotherapy head immobilization masksPublication . Craveiro, D. S.; Loja, M.A.R.; Vieira, Lina Oliveira; Vinyas, M.An effective head immobilization is an important requirement in radiotherapy treatment sessions, although it may also be thought in the future as a precious aid in brain medical imaging. Thus, the present work is focused on the stiffness optimization of a customized head immobilization mask, modeled upon the head reconstruction surface based on computerized tomography images. This paper proposes a strategy supported by a metaheuristic optimization technique and a metamodeling approach for the whole mask, illustrated at its most unfavorable region occurring in the gnathion region.
- A sustentabilidade como fator impulsionador da competitividade empresarial - os objetivos de desenvolvimento sustentável (ODS)Publication . Cabo, Inês Simões do; Seabra, Fernando MiguelA presente dissertação tem como aspetos chave o estudo da integração do desenvolvimento sustentável na estratégia empresarial, mais propriamente, dos Objetivos de Desenvolvimento Sustentável (ODS) da Agenda 2030, estabelecida pela Organização das Nações Unidas (ONU). Desta forma, pretende-se compreender como é que num mundo em constante evolução, onde as tecnologias, práticas organizacionais e expetativas dos clientes estão em persistente mudança, a sustentabilidade pode ser um fator impulsionador de competitividade e fazer a diferença. Mais ainda, pretende-se obter uma visão geral de como é que os ODS, imbuídos na estratégia empresarial, criam valor ao nível do desenvolvimento do talento e carreira das pessoas, da contribuição ativa para com as comunidades, de que forma é que mitigam o impacto ambiental da atividade onde estão presentes, e quais as parcerias que promovem a geração de conhecimento e valor partilhado. A escolha deste tema vai ao encontro do desafio que o desenvolvimento sustentável tem vindo a colocar à sociedade, ao proporcionar oportunidades para a implementação de novas ideias, novos negócios ou até mesmo para a melhoria e reestruturação de modelos de gestão e da performance organizacional por via da otimização de recursos. Será ainda abordada a metodologia utilizada, a qual se baseia no estudo de caso de uma entidade bancária, o BNP Paribas, que comporta um portefólio de negócios diverso e internacional com um perfil heterogéneo e diversificado. Através dos resultados obtidos, conclui-se que os ODS constituem fatores impulsionadores da competitividade empresarial do BNP Paribas, ao possibilitarem a obtenção de ideias inovadoras e diferenciadoras.
- Addressing the patient experience in myocardial perfusion scintigraphyPublication . Grilo, Ana Monteiro; Vieira, Lina; Carolino, Elisabete; Ferreira, Jéssica; Neves, MariaBackground: Myocardial Perfusion Scintigraphy is a medical exam whose purpose is to evaluate myocardial perfusion. This examination due to their procedures can generate some anxiety in patients that can disturb the good performance of the exam. The main objective of this study is to perform an analysis of patient's undergoing myocardial perfusion scintigraphy experience, assess patient`s anxiety and check Nuclear Medicine Department communication and information effectiveness. Material and methods: For this study, the State-Trait Anxiety Inventory (STAI) and two Scan Experience Questionnaires were used. Sixty patients answered the questionnaires before and after myocardial perfusion scintigraphy. Results: Patients reported medium levels of scan-related anxiety and trait anxiety before the myocardial perfusion scintigraphy. After the scan, there is a slight decrease in patients' anxiety. Results of the scan, radiation used, duration of the scan and the injection of the radiopharmaceutical are the most relevant patients' concerns before the scan. 15% of the sample did not receive the necessary information or the most effective way. Conclusions: The results suggest that there are several factors that tend to trigger the patient's experience and anxiety. Strategies to improve patient myocardial perfusion scintigraphy experience at Nuclear Medicine Department are presented.
- Baby keto dietPublication . Cruz, Catarina; Dias, M. Pitta-Grós; Moreira, Ana Catarina; Duarte, Sofia; Vieira, José PedroA dieta cetogénica caracteriza-se por elevado teor de lípidos (gordura) (71-90% do aporte energético), baixo teor de glícidos (hidratos de carbono) (5-19% do aporte calórico) e aporte adequado de proteína. O objetivo principal da adoção desta dieta é reduzir, se não controlar, crises de epilepsia. Todavia, podem também associar-se à dieta cetogénica a redução da farmacoterapia com anti-epiléticos, o aumento do estado de alerta e atenção e melhorias cognitivas e psicomotoras. De modo a monitorizar os ganhos asscoiados à dieta, é importante registar as convulsões/espasmos na forma de diário, assim como a terapêutica com anti-epiléticos e outras melhorias cognitivas e psicomotoras.