CDRsp - Comunicações em conferências internacionais
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- Computational technologies in tissue engineeringPublication . Almeida, H. A.; Bártolo, P. J.In last decades, many advances have been made in order to aid the medical community. Numerous computational technologies have been developed and improved the efficiency in diagnostic and treatment of many diseases. Many of the technologies were developed with the main goal of aiding in the research of genetic and viral diseases. Tissue engineering is a multidisciplinary field that requires the combined effort of cell biologists, engineers, material scientists, mathematicians, geneticists, and clinicians toward the development of biological substitutes that restore, maintain, or improve tissue function. The success of this emerging medical domain relies on the current technological advances. This paper presents an overview of the existing computational technologies that have been implemented in tissue engineering and the design of scaffolds for tissue engineering applications. These computational technologies contemplate medical imaging processing, numerical calculations (structural, vascular and topological) and biofabrication techniques necessary for the scaffolds optimum design and production.
- Spectral Shifters for an enhanced Indoor EnvironmentPublication . Mitchell, Geoffrey R.; Davis, Fred J.Sufficient light levels are essential for effective working in indoor environments. It is well established that the nature of that light has a significant impact on the health of the occupants. In this work we explore the potential for spectral shifters to provide an enhanced working environment. Spectral shifters absorb incident light and re-emit at different wavelengths thus modifying the spectral distribution of the light. Such shifters would be most effective in buildings which have been designed without sufficient care being given to the level of natural lighting within the building.
- Multi-scale computer simulations of multi-tubular components manufactured by water-assisted injection mouldingPublication . Pascoal-Faria, Paula; Alves, Nuno; Kamma-Lorger, Christina S.; Marques, Rita; Gomes, Marta; Venkat, Anurag; Silva, Rui; Bastos, Lourenço; Carneiro, Filipa; Cunha, Jorge; Mateus, Artur; Mitchell, Geoffrey R.Water assisted injection moulding is a recent development in the manufacturing technology associated with injection moulding. Injection moulding involved the high pressure injection of molten plastic in to a preformed metal mould which defines the exterior of the shape of the object. Water assisted injection moulding is a variant with an addition step in which water is injected into the mould after its has been filled with molten plastic. The water jet sweeps out the molten plastic in its path to leave a hollow tube in which the interior of the part is defined by the water jet. This technology is used for preparing tubular components for use in the automotive industry and for domestic appliances. We have been developing the technology to prepare parts with branches in the tubing. We have used fine-element simulations to explore the relationship between the process parameters and the subsequent final part. Of course such simulations only serve to define the exterior and interior of the tubular part. It is clear from the outline of the technology above that the molten plastic is subjected to a complex pressure and temperature variation with time which vary across the part and its location within the mould. The specification of the part is in most cases is limited to the geometry and the materials which is used in its preparation, in this case polyamide6 with 30% glass fibre. From the development of plastic processes over the last 50 years we have learnt that the properties of plastic part depend critically on the processing pathway and in particular the timescale for the transformation from molten material to the semi-crystalline solid state. We know from the use of small-angle and wide-angle scattering mapping of the structure and morphology of the multi-tubular components that the level of crystallinity and the extent of preferred orientation varies throughout the part and this may lead to warpage and other geometrical changes in the part during its service life. We have set out to explore how we can use the temperature and pressure variation from the finite element modelling to predict the structure and morphology at different regions in the part in order to be able to establish the parameters which yield a geometrically correct part which is also homogenous in its structure and morphology and hence properties. This paper describes the approach we have taken to make progress with this complex matter of simulations on multiple scales and the application of this technique to realistic automotive tubular components.
- Tools to define and evaluate morphology mapping, a route to complex structures using direct digital manufacturingPublication . Pinheiro, João; Abdulghani Oliveira da Silva, Saba; Pascoal-Faria, Paula; Sousa, Dora; Carreira, Pedro; Viana, Tânia; Kamma-Lorger, Christina S.; Mitchell, GeoffreyDirect Digital Manufacturing is a new set of technologies which allow objects to be printed directly from a digital definition. Such technologies allow us to manufacture any self-supporting shape, but simply replicating shape is not sufficient for the production of many parts especially those with specific function. We need to be able to generate complex multiscale structures similar to those we observe in nature. Direct digital manufacturing can be seen as method for achieving this, as we can deposit materials with different compositions and different structures in selected volumes and thereby generate a complex structure. This manuscript addresses the challenges of achieving this concept and the tools needed to characterize the parts produced and the variation in the composition and structure. We conclude by discussing how we might design such complex parts.
- Computer-aided optimization in additive manufacturing: Processing parameters and 3D scaffold reconstructionPublication . Alves, Nuno; Gaspar, Miguel Belbut; Pascoal-Faria, PaulaScaffolds are implantable bio-absorbable systems capable of regenerating osteoporotic bone or other native tissues. Additive Manufacturing processes are used to produce scaffolds with customized external shape and predefined internal morphology, allowing some control over pore size and distribution. Despite significant advances in Additive Manufacturing processes, the experimental optimization of processing parameters is time-consuming and expensive usually generating biomaterials waste. Moreover, the manufacturing of such polymeric or hybrid scaffolds requires time-consuming human supervision procedures. Subsequently, measurements of the scaffold’s architecture such as filament diameter, distance between two consecutive filaments, pore geometry and size, and total porosity are usually performed using computer tomography or microscopy, which also requires significant human and physical resources. This research work intends to overcome some aforementioned limitations through the development of a novel approach based on in-situ computer-aided optimization of the extrusion-based processing parameters.
- Tremor modulations across periods with and without voluntary motion and limb load task demands using movement quantificationPublication . Faria , Paula; Patricio, Miguel; Philipiak, Gregor; Caramelo, Francisco; Januario, Cristina; Freire, Antonio; Castelo-Branco, MiguelUnderstanding the neurobiological mechanisms underlying different types of tremor and the altered functional connectivity of the involved areas is a timely goal in clinical neuroscience. If successful, this quest may open new perspectives on how to achieve tremor modulation, which is notably relevant, in Parkinson's disease (PD). Tremor can be characterized by simple parameters such as frequency and amplitude. It is therefore prone to be objectively targeted by neuromodulation and quantitatively investigated using multimodal techniques, such as, accelerometry, EMG and functional Magnetic Resonance Imaging (fMRI). Embarking on the latter challenge requires an a priori knowledge of how effective functional connectivity is altered in PD tremor. This works aims to ascertain which postural and voluntary movement tasks with distinct types of physical load are suitable for designing efficient fMRI protocols, by performing an accelerometry analysis to measure spontaneous and imposed tremor modulation on cohorts of PD patients, essential tremor patients and a group of voluntary healthy controls.
- Global optimization framework for solar building designPublication . Silva, N.; Alves, N.; Pascoal-Faria, P.The generative modeling paradigm is a shift from static models to flexible models. It describes a modeling process using functions, methods and operators. The result is an algorithmic description of the construction process. Each evaluation of such an algorithm creates a model instance, which depends on its input parameters (width, height, volume, roof angle, orientation, location). These values are normally chosen according to aesthetic aspects and style. In this study, the model’s parameters are automatically generated according to an objective function. A generative model can be optimized according to its parameters, in this way, the best solution for a constrained problem is determined. Besides the establishment of an overall framework design, this work consists on the identification of different building shapes and their main parameters, the creation of an algorithmic description for these main shapes and the formulation of the objective function, respecting a building’s energy consumption (solar energy, heating and insulation). Additionally, the conception of an optimization pipeline, combining an energy calculation tool with a geometric scripting engine is presented. The methods developed leads to an automated and optimized 3D shape generation for the projected building (based on the desired conditions and according to specific constrains). The approach proposed will help in the construction of real buildings that account for less energy consumption and for a more sustainable world.
- Two emerging innovative dragons: An analysis of the IPR strategy of China's Huawei and ZTEPublication . Godinho, Manuel Mira; Ferreira, VítorChina has been experiencing a historical take-off iin its use of intellectual property rights (IPR). This paper discusses the IPR strategy of two leading high-tech Chinese firms, Huawei and ZTE, analyzing how they are moving to global leadership in the telecom equipment market. Specifically, the paper addresses their IPR performance with respect to patenting and trademark registration in the most relevant global IPR systems. By 2008 Huawei had already reached world leadership in the international PCT patents applicants’ ranking, while in 2011 Huawei was substituted by ZTE in that position (with Huawei dropping to 3rd place). The paper shows how both firms have developed dynamic capabilities in innovation by investing strongly in R&D. This investment has reflected in a dramatic growth of patent applications. Even if a direct correlation between patent applications and capacity to innovate is not assumed, the growing demand for patents (and more recently trademarks) in different IPR systems reveals an aggressive technological and commercial stance of both firms on the global market.
- A study on the mouldability of technical parts using hybrid moulds and structural foamsPublication . Nogueira, A. A.; Martinho, P. G.; Brito, A. M.; Pouzada, A. S.The production of large plastics parts in small series by injection moulding requires the devel-opment of a new concept of moulds that allows an economic production. This type of products is applied in urban furniture, automotive, nautical and aerospace industries. The use of alternative methodologies for de-sign and manufacturing in a current stage in Portugal gave rise to the concept of hybrid mould. The control and monitoring of the injection moulding process is essential to evaluate the reproducibility of the mouldings and to obtain a product with good quality. Thus the injection mould, which has a significant influence on the final part, must be carefully designed.
- Robust STL processing for extrusion-based manufacturingPublication . Gaspar, M.B.; Martins-Ferreira, N.The slicing and tool-path generation are two fundamental processing steps in rapid prototyping/rapid manufacturing (RP/RM), as well as in CAM. Nevertheless, the specific requirements of the diverse RP/RM techniques are not always addressed by existing tools for CAM. We present a set of efficient and robust algorithms for processing STL files in RP/RM.