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- 3D shape prior active contours for an automatic segmentation of a patient specific femur from a CT scanPublication . Almeida, D.; Folgado, J.; Fernandes, P.R.; Ruben, RuiThe following paper describes a novel approach to a medical image segmentation problem. The fully automated computational procedure receives as input images from CT scan exams of the human femur and returns a three dimensional representation of the bone. This patient specific iterative approach is based in 3D active contours without edges, implemented over a level set framework, on which the evolution of the contour depends on local image parameters which can easily be defined by the user but also on a priori information about the volume to segment. This joint approach will lead to an optimal solution convergence of the iterative method. The resulting point cloud can be an excellent starting point for a Finite Element mesh generation and analysis or the basis for a stereolitography for example.
- Análise da Motivação Autodeterminada dos Praticantes de Trail RunningPublication . Coelho, Luís; Amaro, Nuno; Matos, Rui; Dias, Pedro; Morouço, Pedro
- Assessment of Seismic Behavior of an RC Precast BuildingPublication . Vitorino, Hugo; Batalha, Nadia; Sousa, Romain; Fernandes, Paulo; Varum, Humberto; Rodrigues, HugoPast earthquakes brought attention to the poor performance of precast reinforced concrete structures. One of the problems observed in those structures is related to the beam-to-column connections. The evaluation of different methodologies for the analysis of beam-to-column connections in industrial buildings is an important aspect that should be studied. The numerical analyses developed allowed the study of the effect that different connection properties have on the frequencies of vibration, members drifts, and seismic coefficients. The connection properties were modeled through a macro-element that considers the friction (between concrete–concrete and concrete–neoprene) and the steel dowels. The results showed that the friction between concrete elements and the consideration of the neoprene in the connection has a small impact on the drifts demands in the columns and seismic coefficient of the analyzed structure; on the other hand, the effect of the steel dowel on the drift demand and seismic coefficient is significant. The comparison of the models with different properties and connections allowed a better understanding of the factors with a higher impact on the results.
- Augmented Reality and 3D Technologies: Mapping Case Studies in EducationPublication . Cardoso, Teresa; Coimbra, Teresa; Mateus, ArturLearning anywhere, anytime is becoming ever more a daily routine, due to the increasing and recent growth of information and communication technologies. In the last 5 years, their key characteristic and specifically in the use of mobile equipment and software have been their portability, mobility, and network access. The technological development, including software applications available for the implementation of three-dimensional contents, has been following this trend. Hence, it is important to know whether and how these threedimensional contents are being integrated in educational situations, namely, regarding augmented reality and mobile learning. Thus, a synthesis of Portuguese and international research works and case studies on the use of threedimensional augmented reality is chronologically presented along with the evolution of information and communication technologies. The main goal of this knowledge mapping is to contribute to the state of the art in threedimensional augmented reality technologies in education. In addition, it is aimed at framing the creation and implementation of three-dimensional content in higher education, specifically in the field of mathematics. © Springer-Verlag Berlin Heidelberg 2015.
- Automatic reconstruction of dental CT images using optimizationPublication . Amorim, Paulo H. J.; Moraes, Thiago F. de; Silva, Jorge V. L. da; Pedrini, Helio; Ruben, Rui B.Computed Tomography (CT) is, in several cases, important in dental diagnosis. In fact, the panoramic reconstruction is commonly used in order to have a longitudinal view of the dental arch. Nowadays, dental CT equipments emit lower-dose radiation compared with other CT machines. Thus, dental CT became popular. However, there are some equipments that are not able to make the panoramic reconstruction of the dental arch. In this work, a new method for automatically reconstructing the dental arch based in CT images is developed and discussed. The technique uses optimization methods in order to find the best B-spline that approaches the dental arch.
- Biofabrication Strategies for Tissue EngineeringPublication . Bártolo, Paulo Jorge; Domingos, Marco; Patrício, Tatiana; Cometa, Stefania; Mironov, Vladimir; Bártolo, Paulo JorgeThe success of Tissue Engineering (TE) strongly relies on the capability of designing biomimetic scaffolds closely resembling the host tissue environment. Due to the functional multitude of the native tissues, the considerations are complex and include chemical, morphological, mechanical and biological factors and their mutability with time. Nonetheless, to trigger and/or assist the “natural healing mechanism’’ of the human body it seems essential to provide an appropriate biomechanical environment and biomolecular signalling to the cells. Novel biomanufacturing processes are increasingly being recognized as ideal techniques to produce 3D biodegradable structures with optimal pore size and spatial distribution, providing an adequate mechanical support for tissue regeneration while shaping in-growing tissues. In this chapter, we discuss in detail the most recent advances in the field of biofabrication, providing and updated overview of processes and materials employed in the production of tissue engineering constructs. Bioprinting or ‘’scaffold-less’’ strategies are also presented in this work. They are based on the precise deposition of high-density tissue spheroids or cell aggregates being advantageous alternatives to the current scaffold-based tissue engineering approach.
- Building insulation materials based on agricultural wastesPublication . Gaspar, Florindo; Bakatovich, Aliaksandr; Davydenko, Nadezhda; Joshi, ArpanEcological insulation materials of vegetable raw materials are increasingly widespread. The agricultural wastes can have an interesting role because their use allows the revaluation of agricultural wastes, whose disposal is a serious issue. This chapter gives an overview about the use of agricultural wastes on insulating materials. The source and characteristics of various types of wastes are described. The manufacturing processes considering the types of binders, including the main parameters involved, are explained. An overview is given about the properties of the insulation materials, including thermal conductibility, density, mechanical strength , hygroscopic behavior, acoustic and fire performances, and environmental performance. Suggestions regarding the future research needs are also presented.
- Chapter 8: Structure Development in Electrospun FibresPublication . Mitchell, Geoffrey R.; Mohan, Saeed D.; Davis, Fred J.; Ahn, Kyung-Hwa; Al-Azab, Mohamed; El Hadi, Ahmed; Elliott, Delyth; Kariduraganavar, Mahadevappa Y.; Nagarajan, Anitha; Nazhipkyzy, Meruyert; Geoffrey R MitchellElectrospinning is a process which transforms polymer solutions in to solid fibres in ∼25 ms. In the case of an amorphous polymer, the resultant molecular organisation may not be so different from that of the solution. However, polymers are rich in different types of ordering processes and these may be encountered during electrospinning. In many areas of polymer processing, the processing procedures can have a significant impact on the structure and hence properties of the final product as the selection of the chemical configuration
- Comparative analysis of mandibular symphysis platesPublication . Dinis, Jairson C.; Kemmoku, Daniel T.; Noritomi, Pedro Y.; Silva, Jorge V. L.; Ruben, Rui B.Mandibular symphysis plates, used to heal fractures, can be made from different materials, normally titanium or CoCr alloys. In this work these two materials are tested and compared in order to study the plate's performance in fracture stabilization. This is a computational work performed with the advice of Brazilian maxoillofacial surgeons.
- Comprehensive review on full bone regeneration through 3D printing approachesPublication . Fernandes, Cristiana; Moura, Carla; Ascenso, Rita M.T.; Amado, Sandra; Alves, Nuno; Pascoal-Faria, PaulaOver the last decades, the number of work accidents associated with bone fractures has increased leading to a growing concern worldwide. Currently, autografts, allografts, and xenografts are used for bone regeneration. However, their application has associated risks. Tissue engineering (TE) has brought solutions to address these problems, through the production of temporary supports, providing mechanical support to the formation of new bone tissue and biocompatible and biodegradable scaffolds, which allow cell adhesion and proliferation to ensure bone formation. The combination of materials and structure with the technique to be used will directly influence their physical and chemical properties and, consequently, their action in contributing to bone regeneration. Thus, the focus of this chapter is to perform an exhaustive literature review and a critical analysis of the state of the art in bone TE and present a proposal of an optimized temporary support geometry for bone regeneration in case of large bone defects. For this, it was listed and identified the best choice of biomaterials, fabrication method, cell type and their culture conditions (static vs. dynamic), and/or the inclusion of growth factors for the repair of large bone defects.