Percorrer por autor "Gaspar, M."
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- 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).
- Computer construction of platonic solidsPublication . Gaspar, M.; Leita, M.; Martins-Ferreira, N.; Panda, B. N.In this paper we develop a novel method to generate a 3D geometrical model from 2D planer images. As an example of application, we construct 3D models of each one of the five platonic solids from their platonic graphs.
- Computer tool for maximizing the placement of congruent polyhedraPublication . Gaspar, M.; Alves, N.; Mateus, A.; Martins-Ferreira, N.Given multiple identical polyhedral objects and a parallelepiped container, how should one place the objects so that the largest number fits inside the container? This simple question is important in many applications, yet the answer is elusive. In fact, we know of no published solution for this very general formulation. Still, in many circumstances, further restrictions apply, resulting in a large number of variations requiring different algorithmic strategies. This paper is the continuation of [12] and focus on the fundamental concepts and tools that are used for this kind of problem, such as the no-fit polygon. We also present some of its many variations, giving in particular one that applies to the stereolithographic rapid prototyping technology.
- Finite orbit decomposition of endomapsPublication . Martins-Ferreira, N.; Gaspar, M.In this work we present a vectorized Matlab algorithm for the decomposition of an endomap into its finite orbits.
- Innovative developments on Agile-CAD systemPublication . Gaspar, M.; Alves, N.; Martins-Ferreira, N.; Bártolo, P.Agile-CAD is a reverse engineering computer tool that allows the recovering of outer and inner 3D shapes of existing objects of revolution with constant thickness, using silhouettes computed from one or two digital views. In this context, some improved algorithms were developed in order to provide more accurate and robust tridimensional reconstruction when using a single digital image as source. Experimental results based on real images are presented, demonstrating the good performance of this computer tool.
- Recycling of PET fines waste by density separation: a way to circularity of plasticPublication . Heleno, M. L.; Oliveira, N. S.; Gaspar, M.; Silveira, A.; Vasco, J.Plastic is one of the most used materials due to its specific characteristics such as high flexibility and impact resistance, low cost, formability, light weight and recyclability. In this set, polyethylene terephthalate (PET) based materials are among of the most used plastics on the packaging market worldwide. The European strategy for plastics aims to modify the processes of design, production, use and recycling of plastics. It becomes crucial to study solutions to enhance the circularity of plastics in recycling processes. Therefore, it is mandatory to evaluate the potential separation of PET fines resulting from the recycling process of PET bottles (post-consumer waste), which are still contaminated by other polymers and other materials. The recovery of PET fines was successfully achieved with a multistage density plastics separation process, consisting on the use of solutions of different densities and ensuring the adequate wettability of the residues in the solutions. The addition of this multistage separation process by plastics density, improves PET fines recovery, by achieving 91.7% of pure PET fines from plastic material waste.