Browsing by Author "Teixeira, D."
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- Analysis of metallic nanoparticles embedded in thin film semiconductors for optoelectronic applicationsPublication . Fantoni, Alessandro; Fernandes, Miguel; Vygranenko, Yuri; Louro, Paula; Vieira, Manuela; Silva, R. P. O.; Teixeira, D.; Da Costa Ribeiro, Ana Paula; Prazeres, Duarte; Alegria, ElisabeteThis paper reports about a study of the local plasmonic resonance (LSPR) produced by metal nanoparticles embedded in a dielectric or semiconductor matrix. It is presented an analysis of the LSPR for different nanoparticle metals, shapes, and embedding media composition. Metals of interest for nanoparticle composition are Aluminum and Gold. Shapes of interest are nanospheres and nanotriangles. We study in this work the optical properties of metal nanoparticles diluted in water or embedded in amorphous silicon, ITO and ZnO as a function of size, aspect-ratio and metal type. Following the analysis based on the exact solution of the Mie theory and DDSCAT numerical simulations, it is presented a comparison with experimental measurements realized with arrays of metal nanospheres. Simulations are also compared with the LSPR produced by gold nanotriangles (Au NTs) that were chemically produced and characterized by microscope and optical measurements.
- Ankle Foot Orthosis (AFO) stiffness design for mitigation of ankle inversion injuryPublication . Teixeira, D.; Milho, João; Carvalho, M. S.; Loja, AméliaModelling and simulation of human movement has the potential to improve the design of medical devices and rehabilitation process by enabling the identification of cause-effect relationships in individuals suffering from neurological and musculoskeletal issues. The main goal of this work was to provide a simulation-based stiffness design for an Ankle Foot Orthosis (AFO) that can help to mitigate the risk of a sprain by ankle inversion during the landing in freefall which is known to occur for subtalar angles higher than 25 degrees. Computational simulations were performed using human movement models with and without a passive AFO, to access the AFO sensitivity for the translational stiffness that prevents the cuff from translating with respect to the footplate. The Design of Experiments (DoE) methodology was used to access sensitivities between the three principal directions of the AFO stiffness. Results revealed that the ankle inversion angle was less than 25 degrees when increasingly larger values of translational stiffness were used, although a nonlinear behaviour was observed between the three principal directions of the AFO stiffness, for which injury safe design configurations were obtained.
- Methodology to assess medical processes based on a Failure Mode and Effects Analysis (FMEA)Publication . Sobral, José; Teixeira, D.; Morais, H.; Neves, M.Risk is always present in every activity and several methodologies are often used to reduce or mitigate situations where risk is unacceptable. Founded on this assumption, the present paper has the objective to propose a methodology to assess critical medical processes based on a Failure Mode and Effects Analysis (FMEA), identifying and making a hierarchy of the inherent activities belonging to those processes using a quantified Risk Priority Number (RPN). Thus, based in that knowledge, it is possible to recommend actions with the purpose of lowering risk by acting on the most important failure modes. The methodology proposed will be described for medical processes and all steps to apply the methodology are sufficiently detailed for a broad comprehension in a field where such methodology is not so often applied. An intravenous medication process by infusion pump is analyzed just to demonstrate the applicability of the proposed methodology, reaching to results that are suitable to be considered and evaluated to improve a process that is widely used in hospitals and similar installations. This work brings the opportunity to experts and professional in the field to use the approach proposed for every process where safety is a priority and where undesirable situations must be avoided.