CDRsp - Comunicações em conferências internacionais
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- Additive manufactured stoneware fired in microwave furnacePublication . Santos, Tiago; Ramani, Melinda; Devesa, Susana; Batista, Catarina; Franco, Margarida; Duarte, Isabel; Costa, Luís; Ferreira, Nelson; Alves, Nuno; Pascoal-Faria, PaulaAdditive manufacturing (AM) techniques have revolutionized the concept of building parts not only in laboratory contexts but also in industry environments and can be applied to distinct fields such as the health, automotive and aeronautics sectors [...]
- Adhesion, proliferation and distribution of human mesenchymal stem/stromal cells (MSCs) in Poly(ɛ -caprolactone) (PCL) scaffolds with different pore sizesPublication . Moura, C. S.; Biscaia, S.; Viana, T.; Bártolo, P. J.; Silva, C. L. da; Cabral, J. S.; Ferreira, F. C.Tissue engineering, combining the use of biomaterials, mesenchymal stem/stromal cells (MSCs) and optimized culture medium formulations, is a very promising research field for tissue regeneration. This work is focused on the application of Poly(ε-caprolactone) scaffolds designed to have a spacing gradient between orthogonal fibres with diameters of 0.3mm with pore sizes ranging from 190 to 390 μm. Human bone marrow (BM)-derived MSCs, were used to evaluate cell adhesion, proliferation and distribution within the scaffolds. Specifically, we hypothesized if seeding MSC in scaffold regions with different pore sizes would influence cell proliferation. Therefore, MSC were seeded at the centre of scaffolds with either larger (390 μm) or smaller pores (190 μm). Results obtained showed similar levels of adhesion and proliferation in both configurations, with fold increase in total cell number of 5 after 13 days of cultivation; which indicates that no limitation for cell proliferation within the range of pore sizes studied is observed.
- Aerodynamics of a wheelchair sprinter racing at the 100m world record pace by CFDPublication . Forte, Pedro; Marinho, Daniel A.; Morais, Jorge E.; Morouço, Pedro; Pascoal-Faria, Paula; Barbosa, Tiago M.The aim of this study was to analyze aerodynamics in a racing position of a wheelchair-racing sprinter, at the world record speed. The athlete and wheelchair were scanned at the beginning of the propulsive phase position (hands near the handrims at 12h) for the 3D model acquisition. Numerical simulation was run on Fluent, having as output the pressure, viscosity and total drag force, and respective coefficients of drag at the world record speed in T-52 category. Total drag was 7.56N and coefficient of drag was 1.65. This work helped on getting a deeper insight about the aerodynamic profile of a wheelchair-racing athlete, at a 100m world record speed.
- Alginate/Aloe Vera Hydrogel Films for Biomedical ApplicationsPublication . Pereira, Rúben F.; Mendes, Ausenda; Bártolo, PauloThis paper describes a methodology to produce hydrogel films, composed of alginate and Aloe vera, for wound healing and drug delivery applications. The films were prepared through the solvent-casting method and subsequently submitted to an additional cross-linking step to improve their properties. Alginate films with different Aloe vera contents (5, 15 and 25%) were prepared and its properties evaluated in terms of thickness, transparency, swelling behavior and in vitro degradation. Results show a positive influence of Aloe vera on the transparency of the films, in both dry and wet state. Films were immersed in acetate buffer at pH 5.5 simulating the value of the skin, to evaluate its water absorption capacity. It was found that water absorption increases as the Aloe vera content increases, suggesting that Aloe vera enhances the hydrophilic properties of the films. The in vitro degradation tests were performed through the incubation of the films, for 10 weeks, in a simulated body fluid at 37°C. After this period, films kept its structure integrity exhibiting a weight loss in the range of 14.1-18.6%.
- Analysis of the influence of cladding panels in the seismic behaviour of a prc industrial buildingPublication . Ostetto, Liana; Sousa, Romain; Rodrigues, Hugo; Fernandes, PauloRecent reports on the latest earthquakes in Italy and Turkey have highlighted some critical problems in the connections of cladding panels on industrial precast reinforced concrete (PRC) structures. The panel connections did not perform as expected, causing non-structural damages and, in most cases, leading to the panels overturning. The damage and collapse of these elements may result in significant losses of human lives and large socio-economic impacts due to business interruption. Despite being demonstrated that cladding panels can have a significant contribution on seismic response, these elements are often considered as non-structural, ignoring the interaction with the RC frame, and considering that they do not influence the seismic behaviour. Making use of a simplified macro element, this study assesses the seismic capacity of commonly employed claddings-to-structure connections, as well as the interaction of the cladding panels with the PRC industrial buildings. The analyses were carried out considering a PRC building representative of the Portuguese industrial park, studied with and without cladding panels. The seismic behaviour of the structure are assess considering both non-linear static and dynamic procedures.
- Ask not what additive manufacturing can do for youPublication . Gibson, I.The paraphrase of John F Kennedy’s famous words is for 2 purposes. Firstly it is to acknowledge that there are some people who have considered that it is a major part of their life’s work to promote Additive Manufacturing (AM) technology as primarily a selfless act. AM comprises an outstanding range of technology that should be brought to public attention as a true revolution in how we design and manufacture products. The second purpose is to show that technology development is only one part of this promotion process and that there are other ways in which we can get involved. This paper describes the author’s journey over the (approximately) 20 years since he was introduced to what was then called Rapid Prototyping (RP). It is not a catalogue of research and development projects but rather a list of activities that he has been involved in to help promote and support AM technology over these years. It will describe the conferences, activities, associations and publications that have been created to allow academics and professionals to describe and discuss their work amongst themselves and to the larger society.
- Assessment of existing rc precast industrial buildings according with eurocode 8 - part 3Publication . Batalha, Nádia; Rodrigues, Hugo; Sousa, Romain; Varum, Humberto; Fernandes, PauloPrecast reinforced concrete (PRC) buildings are common in the Portuguese industrial park, as well as throughout Europe. In past earthquakes, namely in Italy and Turkey, this typology of buildings showed a poor performance, namely at structural level. One of the major concerns at structural level regards the connection between the beams and columns. In recent surveys at the Portuguese industrial buildings, it was observed that the buildings built before 1980 present, most of the times, only friction connections between beam and columns. This type of connection is pointed as one of the weakest structural system in this typology of structures and consequently led to serious local and global damage when subjected to seismic loads. Regarding this issue, it was considered appropriate and necessary the study of existing Portuguese buildings with this type of beam-to-column connection and compare it with the use of mechanical connections (dowels), which is a more common solution in the recent buildings. The seismic behaviour of two PRC buildings built with these two solutions was analysed considering nonlinear static and dynamic analyses addressing both global and local (connections) response parameters. When analysed in view of the seismic regulation for existing buildings (Eurocode 8 –Part 3), the results obtained show that, overall, this typology of buildings present an acceptable structural performance. Nonetheless, unsatisfactory performance was observed at the beam-to-column connection in one of the buildings built without steel dowels. The results presented in this study highlight the need to consider adequate models to simulate these connections in order to accurately represent the seismic behaviour on the structure and identify possible limitations in the use of nonlinear static procedures to assess the seismic performance of this typology of buildings. In general, the buildings in study, located in a region of moderate seismicity, exhibited a satisfactory behaviour. However particular attention should be paid to beam-to-column connections, especially in the case of friction connections. In this regard it is important to accurately represent in the model the mechanisms involved in the connections, particularly in buildings located in moderate to high seismic zones.
- BioFab toolbox – Software tools for biofabricationPublication . Alves, N.; Bártolo, P.; Ferreira, N.; Gaspar, M.; Mateus, A.This is a progress report of a project called BioFab Toolbox, funded by the Portuguese National Science Foundation, consisting of the development of a collection of software tools to assist in the process of rapid prototyping and rapid manufacturing of new products. This project is especially designed to produce scaffolds, grafts, implants and other medical applications usually designated as biofabrication (biofab).
- Biomechanics modeling for functional analysis: Sheep modelPublication . Silva, Rui; Amado, Sandra; João, Filipa; Morouço, Pedro; Pascoal-Faria, Paula; Alves, Nuno; Veloso, AntónioThe aim of the present manuscript was to provide information on the suitability of using ovine as models for conducting in vivo bone tissue engineering studies, regarding the biomechanical considerations. Despite the need of knowledge of the animal model used for bone tissue research a good planning and study design is equal important. The purpose of this review is to contribute to extrapolation of reliable data for those who pretend to use the ovine model in tissue engineering and regenerative medicine.
- Characterisation of PCL and PCL/PLA Scaffolds for Tissue EngineeringPublication . Patrício, T.; Domingos, M.; A. Gloria; Bártolo, P.This paper investigates the use of PCL and PCL/PLA scaffolds produced using a novel additive biomanufacturing system called BioCell Printing. PCL/PLA blends were prepared using melt blend and solvent casting techniques. Scaffolds with 0/90° architecture and 350 μm of pore size were morphologically evaluated using scanning electron microscopy and atomic force microscopy. Biological tests, using osteosarcoma cell line G-63, were performed using the Alamar Blue Assay and Alkaline Phosphatase Activity. Results show that the BioCell Printing system produces scaffolds with regular and reproducible architecture, presenting no toxicity and enhancing cell attachment and proliferation. It was also possible to observe that the addition of PLA to PCL scaffolds strongly improves the biomechanical performance of the constructs.