CDRsp - Comunicações em conferências internacionais
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- Optimization of Scaffolds in Alginate for Biofabrication by Genetic AlgorithmsPublication . Rezende, Rodrigo; Rezende, Mylene; Bártolo, Paulo; Mendes, Ausenda; Filho, Rubens Maciel; Bartolo, Paulo; Mendes, AusendaWith an increasing in the rate of transplants due to damaged or affected tissues or organs by accidents or diseases and also by the aging of the population in many countries as Brazil, have motivated the research of some novel and alternative ways focused on restoring and replacing tissues. Biofabrication by means of Rapid Prototyping techniques can help in the fashioning and final production of scaffolds devoted to support and stimulate the growth of new tissues. For soft tissues, a biomaterial known as Alginate has been studied and used as raw-material for scaffolds fabrication. A scaffold must guarantee good strength and stiffness at the same time the material degrades gradually. In this work, a single mathematical model experimentally obtained that describes an interesting mechanical behavior of the degradation of alginated-scaffolds is developed. The optimization process scheme using Genetic Algorithms to maximize the elastic modulus and therefore to aid the design of scaffolds in alginate is proposed. The optimization is very welcome to tissue engineering and Biofabrication.
- 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.
- Quantification and Modulation of Tremor in Rapid Upper Limb MovementsPublication . Faria, Paula; Leal, Adriana; Freire, António; Januário, Cristina; Patrício, Miguel; Castelo-Branco, MiguelTremor is a manifestation of a variety of human neurodegenerative diseases, notably Parkinson’s disease (PD), a chronic disease that affects one in 100 people over age 60 years. Recent research indicates that more than five million worldwide have PD. This disease is primarily caused by a progressive loss of dopamine neurons in the nigrostriatal system that leads to widespread motor symptoms such as bradykinesia, rigidity, tremor and postural instability. Although the diagnosis of PD remains clinical, advances in functional and structural imaging have improved the ability to differentiate between PD and Essential Tremor (ET), as well as between different akinetic-rigid syndromes. No definitive test or biomarker is available for PD, so the rate of misdiagnosis is relatively high. It is therefore crucial to be able to characterize tremor in PD and ET as it is a very common feature at the onset of both diseases. This is made possible with a combination of a neuroscientific and methodological multi-modal imaging approaches, namely kinetic recording methods using accelerometers to quantify tremor amplitude and frequency and functional magnetic resonance imaging (fMRI). These allow the identification of the neural underpinnings of tremor in both PD and ET patients, which in fact have been surprisingly difficult to decipher. In this work we aim to find which tasks involving upper limb movements are suitable to modulate both PD and ET tremor. The same tasks are considered with and without added loading. The resulting analysis will allow designing an efficient fMRI protocol aiming at the identification of the cortical circuits responsible for the modulation of tremor.
- Numerical Calculations in Tissue EngineeringPublication . Almeida, Henrique de Amorim; Bártolo, Paulo J.The design of optimized scaffolds for tissue engineering is a key topic of research, as the complex macro- and micro- architectures required for a scaffold depends not only on the mechanical properties, but also on the physical and molecular queues of the surrounding tissue within the defect site. Thus, the prediction of optimal features for tissue engineering scaffolds is very important for its mechanical, vascular or topological properties. The relationship between high scaffold porosity and high mechanical properties is contradictory, as it becomes even more complex due to the scaffold degradation process. A scaffold design strategy was developed, based on the finite element method, to optimise the scaffold design regarding the mechanical and vascular properties as a function of porosity. Scaffolds can be considered as a LEGO structure formed by an association of small elementary units or blocks. In this research work, two types of family elementary scaffold units were considered: non-triple periodic minimal surfaces and triple periodic minimal surfaces that describe natural existing surfaces. The main objective of this work is to present the undergoing research based on numerical simulations for the evaluation and prediction of the scaffold's behaviour under structural and vascular loading, and its topological optimisation.
- Further remarks on the "Smith is Huq" conditionPublication . Martins-Ferreira, Nelson; Van der Linden, TimWe compare the Smith is Huq condition (SH) with three commutator conditions in semi-abelian categories: first an apparently weaker condition which arose in joint work with Bourn and turns out to be equivalent with (SH), then an apparently equivalent condition which takes commutation of non-normal subobjects into account and turns out to be stronger than (SH). This leads to the even stronger condition that weighted commutators in the sense of Gran, Janelidze and Ursini are independent of the chosen weight, which is known to be false for groups but turns out to be true in any two-nilpotent semi-abelian category.
- Thermal analysis of an extrusion system of a 3-D bioprinterPublication . Ribeiro G.S.; Silva J.V.L.; Freitas D.; Bartolo P.; Almeida, Henrique de Amorim; Silveira Z.C.This work presents a finite element thermal analysis of a 3-D bioprinter desktop based on Fused Deposition Modeling (FDM) with applications on tissue engineering, designed by the Centre for Rapid and Sustainable Product Development - Leiria, Portugal. The purpose of this work it is compare three possibilities of temperature control of the machine during the extrusion process, considering the use of a biodegradable polyester (Polycaprolactone - PCL) as raw material. The first two configurations simulate approaches typically adopted in an attempt to keep the polymer as close as possible to 80 °C and prevent its premature solidification at a critical point. The third configuration considers a hypothetical material substitution to enhance thermal conductivity. The results indicate that the first two configurations are not sufficient to achieve total control of the polymer temperature. However, the third configuration show a significant potential to improve the thermal control of the extrusion process.
- A eficiência da materialidade - O recurso a ferramentas digitais de simulação e fabricação aditiva na procura de uma maior eficácia dos dispositivosPublication . Gonçalves, Sérgio; Mateus, João Vasco; Hernandis-Ortuño, BernabéA praxis do Design de produtos, condicionada pelas crises sociais e ambientais que o mundo atravessa, deve passar pela procura de uma cada vez maior eficiência dos objetos na sua dimensão ambiental. Embora esta questão esteja a jusante de questões eventualmente mais relevantes na minimização deste problema, e que têm a ver com a legitimação da própria existência dos dispositivos, a otimização do recurso a matérias primas no fabrico de objetos é de fulcral importância. A possibilidade de otimizar os produtos pela redução da incorporação de matéria prima no seu fabrico e adequar o material a uma determinada utilização é central no seu processo de desenvolvimento. Por outro lado, as novas possibilidades trazidas pela fabricação aditiva no sentido de reduzir a quantidade de materiais e processos industriais associados à produção de componentes técnicos complexos permite perspetivar uma melhoria significativa do impacto ambiental tradicionalmente associado à sua obtenção. O presente artigo procura examinar como as tecnologias digitais de análise, otimização e fabricação aditiva poderão constituir uma resposta viável para uma produção mais eficiente do ponto de vista da incorporação de recursos não-renováveis e da minimização do impacto ambiental associado às tecnologias de produção tradicionais.
- Optimization of a Wood Plastic Composite to Produce a New Dynamic Shading SystemPublication . Martins, G.; Antunes, F.; Mateus, Artur; S. Baptista; C. MalçaThe shading systems of the windows may play a protagonist role in the reduction of energy consumption in lighting, artificial ventilation and air conditioning, contributing to sustainable development regarding bioclimatic architecture and improvement of the energetic efficiency in buildings. This work, resulting from a partnership between architecture and materials science, reports the development of an innovative and dynamic shading system that simultaneously fulfils various aesthetic, functional and environmental requirements. The original design of the system, derived from this collaboration, enables an industrial low cost production in virtue of the selection of technologies and materials concurrently adequate to multiple objectives. This work also aims at contributing to a sustainable construction through the use of eco-friendly materials such as biocomposites produced from recyclable polymers and vegetable fibres, using extrusion as processing technology both for blending the raw materials and for the shutter units production. The optimization of materials for this specific application involved wood plastic composites (WPC) based on high density polyethylene (HDPE), industrial residues of pine sawdust and additives such as coupling agents, pigments and UV protectors. Results showed that the optimized WPC made from recycled industrial pine wood residues presents thermal stability, mechanical strength and water absorption appropriate to be applied in the production of the new architectural solutions such as the innovative shading system presented.
- DLL architecture for OFDM based VLC transceivers in FPGAPublication . Duarte, Luis; Rodrigues, Luis; Alves, Luis N.; Ribeiro, Carlos; Figueiredo, MónicaThis paper addresses the problem of achieving high bandwidth in a DLL design for OFDM based VLC broadcast systems. It describes the implementation of efficient Data Link Layer (DLL) and Forward Error Correction (FEC) modules in a Xilinx FPGA. The proposed DLL aims at furnishing the adequate means to fragment and route both high data-rate (HDR) and moderate data-rate (MDR) service requests while maintaining a continuous transmission flow. The FEC modules aims at providing sufficient error correction capabilities with reasonable computation overheads. Another goal was to develop these modules under a globally asynchronous locally synchronous paradigm, ensuring high modularity and performance.
- Study on the aerodynamic behavior of a UAV with an applied seeder for agricultural practicesPublication . Felismina, Raimundo; Reis Silva, Miguel; Mateus, Artur; Malça , CândidaIt is irrefutable that the use of Unmanned Airborne Vehicle Systems (UAVs) in agricultural tasks and on the analysis of health and vegetative conditions represents a powerful tool in modern agriculture. To contribute to the growth of the agriculture economic sector a seeder to be coupled to any type of UAV was previously developed and designed by the authors. This seeder allows for the deposition of seeds with positional accuracy, i.e., seeds are accurately deposited at pre-established distances between plants [1]. This work aims at analyzing the aerodynamic behavior of UAV/Seeder assembly to determine the suitable inclination - among 0°, 15° and 30° - for its takeoff and for its motion during the seeding operation and, in turn, to define the suitable flight plan that increases the batteries autonomy. For this the ANSYS® FLUENT computational tool was used to simulate a wind tunnel which has as principle the Navier-Stokes differential equations, that designates the fluid flow around the UAV/Seeder assembly. The aerodynamic results demonstrated that for take-off the UAV inclination of 30° is the aerodynamically most favorable position due to the lower aerodynamic drag during the climb. Concerning flying motion during the seeding procedure the UAV inclination of 0° is that which leads to lower UAV/Seeder frontal area and drag coefficient.
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