Browsing by Author "Silva, R."
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- Calibration of the numerical model of a freight railway vehicle based on experimental modal parametersPublication . Ribeiro, Diogo; Bragança, C.; Costa, C.; Jorge, P.; Silva, R.; Arêde, A.; Calçada, R.The simulation of the dynamic behavior of the train-track system is strongly dependent on the accuracy of the numerical models of the train and track subsystems. The use of calibrated numerical models of the railway vehicles, based on experimental data, enhances their ability to correctly reproduce the dynamic responses of the train under operational conditions. In this scope, studies involving the experimental calibration of freight wagon models are still scarce. This article aims to fill this gap by presenting an efficient methodology for the calibration of a numerical model of a freight railway wagon based on experimental modal parameters. A dynamic test was performed during the unloading operation of the train, adopting a dedicated approach which does not interfere with its tight operational schedule. From data collected during the dynamic test, five natural frequencies and mode shapes associated with rigid-body and flexural movements of the wagon platform were identified through the Enhanced Frequency-Domain Decomposition (EFDD) method. A detailed 3D finite-element (FE) model of the loaded freight wagon was developed, requiring precise knowledge of the vehicle design details which, in most situations, are difficult to obtain due to confidentiality reasons of the manufacturers. The model calibration was performed through an iterative method based on a genetic algorithm and allowed to obtain optimal values for seven numerical parameters related to the suspension’s stiffnesses and mass distribution. The stability of the parameters considering different initial populations demonstrated the robustness of the optimization algorithm. The average error of the natural frequencies decreased from 8.5% before calibration to 3.2% after calibration, and the average MAC values improved from 0.911 to 0.950, revealing a significant improvement of the initial numerical model.
- Calibration of the numerical model of a freight railway vehicle based on experimental modal parametersPublication . Ribeiro, Diogo; Bragança, C.; Costa, C.; Jorge, P.; Silva, R.; Arêde, A.; Calçada, R.The simulation of the dynamic behavior of the train-track system is strongly dependent on the accuracy of the numerical models of the train and track subsystems. The use of calibrated numerical models of the railway vehicles, based on experimental data, enhances their ability to correctly reproduce the dynamic responses of the train under operational conditions. In this scope, studies involving the experimental calibration of freight wagon models are still scarce. This article aims to fill this gap by presenting an efficient methodology for the calibration of a numerical model of a freight railway wagon based on experimental modal parameters. A dynamic test was performed during the unloading operation of the train, adopting a dedicated approach which does not interfere with its tight operational schedule. From data collected during the dynamic test, five natural frequencies and mode shapes associated with rigid-body and flexural movements of the wagon platform were identified through the Enhanced Frequency-Domain Decomposition (EFDD) method. A detailed 3D finite-element (FE) model of the loaded freight wagon was developed, requiring precise knowledge of the vehicle design details which, in most situations, are difficult to obtain due to confidentiality reasons of the manufacturers. The model calibration was performed through an iterative method based on a genetic algorithm and allowed to obtain optimal values for seven numerical parameters related to the suspension’s stiffnesses and mass distribution. The stability of the parameters considering different initial populations demonstrated the robustness of the optimization algorithm. The average error of the natural frequencies decreased from 8.5% before calibration to 3.2% after calibration, and the average MAC values improved from 0.911 to 0.950, revealing a significant improvement of the initial numerical model.
- Designing a software for qualitative and quantitative analysis of oropharyngeal swallowing by videofluoroscopyPublication . Silva, A; Santos, Ricardo; Silva, R.; Coimbra, M.Swallowing is a dynamic, complex and synergistic process, composed of three phases with a refined neuromotor control. A malfunction of this process, denominated dysphasia, can occur in any age like a result of congenital, structural, functional and/or medical problems.
- Incapacidade funcional cervical, lombar e membros superiores em funcionários do Grupo CESPUPublication . Silva, R.; Sousa, G.; Brochado, G.; Rocha, P.; Coelho, A.; Lopes, S.As Lesões Músculo-Esqueléticas Relacionadas com o Trabalho foram consideradas pela Organização Mundial de Saúde como uma doença de saúde pública. Estudos realizados até ao momento indicam que a tendência da prevalência de incapacidades associadas a estas lesões, venha a aumentar nos próximos anos sendo que, as regiões anatómicas que reportam sintomatologia associada ao trabalho e que por sua vez poderá criar incapacidade para o indivíduo são, a região cervical, região lombar e membro superior. Destas três regiões referidas é consensual que a região lombar é aquela com maior prevalência de sintomatologia.
- Optimization and validation of a new cytology stain – CytoPath line®Publication . Teixeira, C.; Fernandes, S.; Silva, R.Cytology plays an important role in the screening and diagnosis of cervical cancer. The correct staining of cervical smear allows the recognition of essential characteristics for the diagnosis of some pathologies. However, given the existence of flaws in the current staining procedures, the development of new staining techniques as well as the optimization of the existing ones is important. Recently, a new staining line - the CytoPath line® is being developed by DiaPath S.p.A. The objective of this work is to evaluate its performance in the staining of gynecological cytology samples.
- Powered smart textile-based exoskeleton for human support movementPublication . Ferreira, C.; Fertuzinhos, A.; Silva, R.; Ramalho, M.; Vale, B.; Silva, J.; Costa, L.; Oliveira, C.; Ramôa, A.; Aguiar, F.; Pilastri, A.; Matta, A.; Dias, P.; Sampaio, R.; Machado, D.; Costa, M.; Roças, A.; Madureira, P.; Moreira, Juliana; Pereira, J. R.; Pereira, C.; Pereira, F. B.Industrial environments require people’s physical efforts related to excessive force, poor posture, and repetitive tasks that increase the risk of developing musculoskeletal diseases. Due to the high prevalence of postural complaints and consequent global health burdens, a significant demand has been conducted to build and implement powered lower and upper limb devices for human enhancement, considering the working layout/position, anthropometric and ergonomic data to generate valuable information for posture correction guidance.
- Validation of app and phone versions of the Control of Allergic Rhinitis and Asthma Test (CARAT)Publication . Jácome, C.; Pereira, R.; Almeida, R.; Amaral, Rita; Correia, M. A.; Mendes, S.; Vieira-Marques, P.; Ferreira, J. A.; Lopes, I.; Gomes, J.; Vidal, C.; López Freire, S.; Méndez Brea, P.; Arrobas, A.; Valério, M.; Chaves Loureiro, C.; Santos, L. M.; Couto, M.; Araujo, L.; Todo Bom, A.; Azevedo, J. P.; Cardoso, J.; Emiliano, M.; Gerardo, R.; Lozoya, C.; Pinto, P. L.; Neves, A. Castro; Pinto, N.; Palhinha, A.; Teixeira, F.; Ferreira-Magalhães, M.; Alves, C.; Coelho, D.; Santos, N.; Menezes, F.; Gomes, R.; Rodrigues, J. C. Cidrais; Oliveira, G.; Carvalho, J.; Alves, R. Rodrigues; Moreira, A. S.; Costa, A.; Abreu, C.; Silva, R.; Morête, A.; Falcão, H.; Marques, M. L.; Câmara, R.; Cálix, M. J.; Bordalo, D.; Silva, D.; Vasconcelos, M. J.; Fernandes, R. M.; Ferreira, R.; Freitas, P.; Lopes, F.; Fonseca, J. AlmeidaAssessment of asthma control at every opportunity is recommended. Control of Allergic Rhinitis and Asthma Test (CARAT) is a patient reported outcome measure commonly used to assess asthma control in clinical practice.It includes ten questions answered in a 4 point Like rt scale that address upper and lower airway symptoms, sleep interference, limitation of activities , and the need to increase medication over a 4 week period. CARAT is frequently administered on paper during medical visits, but digital versions through website and mobile apps are available.