ESTiG - Posters em Encontros Científicos Internacionais
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- Dolphin-complab: a virtual compilers laboratoryPublication . Matos, Paulo; Henriques, PedroThe goal of this paper is to present the Dolphin-COMPilers LABoratory (COMPLAB), an integrated environment conceived for the investigation, teaching, development and use of compilers. It employs Web technologies to make available a virtual laboratory containing a set of functionalities to: implement, analyze, test, evaluate and simulate compiler routines. This environment aims to support the classes of Language Processors of the graduate and post-graduate levels of the Computer Science courses, inside and outside of the classroom. The environment, reachable using a simple Web browser (connected to the Internet), should supply three distinct levels of access that correspond to three distinct types of users: conventional users, that can access to the laboratory to work on the projects where they are registered using the tools supplied by the DOLPHIN-COMPLAB; the project coordinators responsible for the management of the project (define the goals, choose tools and components, manage the users of the project, …); and the main coordinators that are responsible for the laboratory (registration of projects, integration of components, laboratory cleanness, etc). A conventional user has access to a several tools that support the two main stages of the compilers development process: the implementation and test. The functionalities supplied for the implementation allow to develop, modify and change the compiler components and the compiler structure. To support the test and evaluation of the compilers, it is supplied an integrated development environment where the users can analyze the behavior of the several compilation tasks and measure the performance of the compiler.
- Influence of corrugation angle in the stirred yoghurt processing in plate heat exchangersPublication . Fernandes, Carla S.; Afonso, Isabel M.; Melo, Luis F.; Maia, João M.Research on heat transfer of non-Newtonian fluids during thermal processing is useful to optimise the heat exchanger design, as well as to define quality levels of the final product. In the present study, a nonisothermal and non-Newtonian flow in plate heat exchangers was simulated numerically, in order to evaluate the influence of corrugation angle on the thermal and hydrodynamics characteristics of yoghurt during cooling in a plate heat exchanger (PHE). Cooling treatment of stirred yoghurt is usually carried out in PHEs since these equipments are suitable for liquid-liquid heat transfer duties that require uniform and rapid cooling or heating. In this operation, two mechanisms of heat transfer occur: conduction, in the plates, and convection inside the channels. The set of equations that describe mathematically the problem were the Navier-Stokes equations, for incompressible and stationary flow, and Fourier’s law for the conduction problems. Additionally, a constitutive model that describes the rheological properties of yoghurt under the cooling conditions has to be established in order to define totally the problem. The used model was proposed by Afonso et al. (2003) and takes into account the influence of shear rate and temperature
- Reduction method with simulated annealing for semi-infinite programmingPublication . Pereira, Ana I.; Fernandes, Edite M.G.P.Semi-infinite programming (SIP) problems are characterized by a finite number of variables and an infinite number of constraints. The class of the reduction methods is based on the idea that, under certain conditions, it is possible to replace the infinite constraints by a finite set of constraints, that are locally sufficient to define the feasible region of the SIP problem. We propose a new reduction method based on a simulated annealing algorithm for multi-local optimization and the penalty method for solving the finite problem.
- Effect of corrugation angle on the hydrodynamic behaviour of power-law fluids during a flow in plate heat exchangersPublication . Fernandes, Carla S.; Dias, Ricardo P.; Nóbrega, João M.; Maia, João M.Hydrodynamic behaviour of a non-Newtonian fluid in PHEs channels with different corrugation angles was numerically studied and relations between Fanning friction factors and Reynolds number were developed, considering and discarding the effect of temperature on viscosity.
- Um problema de teoria de grafosPublication . Barbedo, Inês; Pacheco, Maria F.Uma etapa fulcral da resolução de um problema é a sua representação por um diagrama. Um grafo pode ser a ferramenta ideal para a esquematização de uma situação, podendo representar redes físicas (redes viárias, circuitos eléctricos) assim como as interacções que ocorrem entre indivíduos num ecossistema ou numa teia de relações sociais. Sendo os conceitos introdutórios da Teoria de Grafos de fácil compreensão mesmo por alunos numa fase inicial da sua formação, ela é um tópico motivador e um auxiliar precioso na compreensão, modelação e resolução de problemas em que exista um conjunto de objectos de algum modo relacionados. Pretende-se abastecer três casas de electricidade, gás e água de modo a que nenhuma das nove ligações se cruze com outra. Será possível representar no papel tal situação?
- Effect of corrugation angle on the thermal behaviour of power-law fluids during a flow in plate heat exchangersPublication . Fernandes, Carla S.; Dias, Ricardo P.; Nóbrega, João M.; Maia, João M.Local and average Nusselt numbers of power-law fluids were studied on PHE channels with different corrugation angles, being the effect of the temperature on viscosity also considered on the thermal correlations development.
- Asphalt pavement temperature predictionPublication . Minhoto, Manuel; Pais, Jorge; Pereira, Paulo A.A.A 3-D finite element model (FEM) was developed to calculate the lemperature of an asphtalt rubber pavement localed in the Northeast of Portugal. The goal of the case study presented in this paper is to show the good accuracy temperature prediction tha can be obtained with this model when compared with the field pavement thermal condition obtained during a year. lnput data to the model are the hourly values for solar radiation and temperature and the mean daily value of wind speed obtained from a meteorological station. The therminal response of a multilayered pavement structure is modelled using a FEM transient thermal analysis and each analysis was initiated with the full deph constant initial temperature abtained from field measurements. For each analysed day, the pavement temperature was measured at a new pavement section, located in IP4 main road, near Bragança, in the north of Portugal. At this location, seven thermocouples were installed in the asphalt rubber and conventional mix layer, at seven different depths. These paviment data was used to validate this simulation model, by comparing model calculated data with mesured pavement temperatures. As conclusion, the 3-D finite-element analysis proved to be an interesting tool to simulate the transient behavior of the asphalt pavements. The presented simulation model can predict the pavement temperature at diferrent levels of bitumious layers with good accuracy.
- Measuring displacement field detection of unbounded regions in a single lap Joint with moiréPublication . Ribeiro, J.E.; Vaz, M.A.P.; Lopes, Hernani; Monteiro, Jaime M.; Piloto, P.A.G.The goal of this work is the development of an experimental technique to measure the displacement field and to perform detection of unbonded regions [1] in a single lap joint [2, 3]. The proposed experimental technique is based on the use of Moiré Interferometry. It is a field technique that allows in-plane displacement measurements without contact and with high resolution [4, 5]. Grating replication techniques were developed to record high quality diffraction gratings onto the specimen’s surfaces [6]. It was also, developed an optical assembly of laser interferometry used to generate the master grating (virtual) [7]. A tension load was applied to a lap joint and its deformation was accessed by the interference between the reference grating, recorded on the object surface, and virtual master grating generated by laser interferometry. A phase shifting technique [8] was developed to allow the phase map calculation. Image processing techniques [9] will be used to assess the in-plane displacement field. A finite elements code (ANSYS®) will be used to calculate the displacement field [10, 11]. An unbonded region in a single lap joint was numerically simulated and the obtained results will be compared with those obtained in the experimental work. In the figure 1 it’s possible to observe the displacement field, measured in a horizontal direction, of a single lap sound joint: and the results obtained by numerical simulation.
- Measuring displacement field and detection of unbonded regions in a single lap joint with Moiré intereferometryPublication . Ribeiro, J.E.; Vaz, M.A.P.; Lopes, Hernani; Monteiro, Jaime M.; Piloto, P.A.G.Adhesives are increasingly being used to replace traditional fastening methods in industrial applications such as welding, bolts and rivets. In cars and other transport applications, weight reduction is a key factor in new developments, hence the use of lightweight adhesives is rapidly expanding. Adhesives are used to bond many different material types including ceramics, metals, glass, plastics and composites. The key advantages of adhesives include the distribution of loads across the entire joint area, excellent fatigue properties, attenuation of mechanical vibrations and noise, sealant functions, reduction in galvanic corrosion between dissimilar metals, and a faster more cost-effective assembly method. The goal of this work is the development of an experimental technique to measure the displacement field and to perform detection of unbonded regions in a single lap joint. The proposed experimental technique is based on the use of Moiré Interferometry.
- Bioacumulação de poluentes metálicos (CD2+) por briófitas aquáticas fontinalis antipyreticaPublication . Martins, Ramiro; Boaventura, RuiO objectivo deste trabalho é compreender em termos quantitativos e qualitativos a acumulação e libertação de Cd(II) em solução aquosa, por uma briófita aquática - Fontinalis antipyretica – na perspectiva duma aplicação, quer na biomonitorização de cursos de água, quer na descontaminação de efluentes industriais. A acumulação de cádmio e posterior eliminação pelo musgo foi estudada em laboratório expondo as plantas a diferentes concentrações de cádmio na gama, 0,5 – 2,5 mg l-1, durante um período de contaminação de 144 h, e depois a água isenta de metal durante um período de descontaminação de 192 h. Foi ajustado um modelo cinético de transferência de massa de primeira ordem aos dados experimentais.