ESTG - Artigos em revistas internacionais
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- City marketing and identity: Study applied for small cities in rural and peripheral areasPublication . Moreira, Jacinta Raquel; Silva, Maria JoséThis research aims to study the identity of cities, presenting a proposed conceptual model and applying the model of the city identity study to the case of a small city in rural and peripheral areas of Portugal, namely Covilha. It has as reference sources several approaches, conducted construction of the model, and this is comprised of four different forms: current identity, communicational identity, ideal identity and desired identity. For data collection two strategies were used: document analysis and in depth personal semi-structured interviews. These data were processed through content analysis techniques. Results obtained from the analysis of cities' identities should generate a competitive positioning, differentiating and reinforcing the city's attractions, which is only possible through the construction of a clear, strong, rich and effective identity. In terms of implications, the study and recommendations are made having in view a better coordination among the different actors in the institutions involved so that the city marketing they offer can be more effective in the future. This paper presents an innovative contribution since the results obtained conducted dissemination of insightful and original marketing knowledge regarding the city marketing. This study highlights the contributions that marketing can provide in what regards the development of small cities, giving special emphasis to their identity.
- Influence of Local Properties on Fatigue Crack Growth of Laser Butt Welds in Thin Plates of High-Strength Low-Alloy SteelPublication . Riofrío, Patricio G.; Jesus, Joel de; Ferreira, José A. M.; Capela, CarlosIn this work, local properties such as hardness and fatigue crack grow rate in the heat‐affected zone of four laser‐welded butt joints in thin high‐strength low‐alloy steel were ex-amined, so as to explain and predict fatigue lives at high stress levels through the fracture mechanics approach. The different welded series presented a similar fatigue crack growth rate in the heat‐affected and fusion zones, but lower than base metal due to the higher hardness of the bainitic–martensitic microstructure verified in the welded series. The results showed that at high stress levels in the as‐welded condition, the fatigue initiation stage can be neglected and assume some types of cracks, with an initial crack of 0.07 mm and appropriate fatigue crack growth rates, estimates of fatigue life close to the experimental results were obtained.
- Impact response of nano reinforced mat glass/epoxy laminatesPublication . Ferreira, J.A.M.; Santos, D.S.C.; Capela, C.; Costa, J.D.M.The present work intends to characterize the effect that nanoclay and carbon nanotubes matrix reinforcements have on low velocity impact response of epoxy/glass fiber composites. The composite matrix used was the epoxy resin Biresin® CR120 combined with the hardener CH120-3 and the fiberglass triaxial mats ETXT 450. The results of the present paper are discussed in terms of load-time, load-displacement, energy-time diagrams and damage. The incorporation of nanoparticles produces only small improvement of the impact response in terms of the peak load and specific recovery energy. Peak load decreases slightly with increasing percentage of nanoparticles reaching a maximum decrease of 6 % for 3 wt% of nanoclays. Specific recovery energy increases in comparison with control formulation, around 14–18 % for 0.5 wt% addition of nanotubes and 7–15 % for 1 wt% of nanoclays, respectively. Specific recovery energy tends to decrease for higher percentages of nanoparticles in consequence of its poor distribution. Damaged area apparent shows a small reduction with nanoparticle content.
- Multi-objective optimization using NSGA-II for power distribution system reconfigurationPublication . Vitorino, Romeu M.; Jorge, Humberto M.; Neves, Luís P.This study proposes a new strategy to solve the problem of radial power distribution system (RDS) recon figuration in a multi-objective and constrained environment. Due to the presence of various conflicting objectives and constraints, the proposed strategy uses the Elitist Non-Dominated Sorting Genetic Algorithm-II (NSGA-II), an effective evolutionarymulti-objective optimization technique. NSGA-II determines a set of pareto-optimal solutions for the power distribution system topology, considering power losses, reliability and investment in tie-switches. The methodology adopted to evaluate the RDS reliability uses a non-sequential Monte Carlo Simulation and is focused on the impacts of branch failures for interruption energy assessment. The effectiveness of the proposed methodology is demonstrated on a 69 bus RDS.
- Structure–property relationships in polyethylene based films obtained by blow molding as model system of industrial relevancePublication . Duraccio, Donatella; Mauriello, Amalia; Cimmino, Sossio; Silvestre, Clara; Auriemma, Finizia; Rosa, Claudio de; Pirozzi, Beniamino; Mitchell, Geoffrey RobertA method for the study of structure-property relationships of polyethylene (PE)-based films of potential use in food packaging has been set up. The approach has been demonstrated in the case of films obtained by blow-molding using model mixtures of two different polyethylenes, namely a metallocene-made grade of linear low density polyethylene (mLLDPE) and a low density polyethylene (LDPE). We show that physical properties important for numerous applications of these films, such as water vapor and oxygen permeability, toughness and stress strength, are related to the molecular structure and structural and morphological parameters of the blends, in particular, thickness of amorphous layers in lamellar stacks, lamellar thickness, lamellar twisting, and degree and type of branching.
- Microwave Propagation Modeling and Measurement of Scattering and Absorption Inside a Canopy Using the FDTD TechniquePublication . Caldeirinha, Rafael F. S.; Al-Nuaimi, Miqdad O.This paper proposes a novel method aimed at modeling microwave scattering and absorption inside a canopy, arising from the interaction with the individual components of the vegetation specimen, starting from primary models for leaves, trunk and branches. The method is based on the finite-difference time-domain (FDTD) technique to predict the 3-dimensional re-radiation fields of the entire tree, by combining the effects of the single elements forming the tree. Appropriate measurements performed in an anechoic chamber environment at microwave frequencies, i.e. 20 GHz, and in the forward scattering region, provided both model validation and a deeper insight into the problem. The model is shown to be capable of predicting the near-field radiated signal and the radar cross section (RCS). The predictions yielded good agreement with measurements and provides a good basis for a planning model capable of accounting for single trees in the radio path.
- In-plane Response of Masonry Infill Walls: Experimental Study using Digital Image CorrelationPublication . Furtado, André; Ramos, T.; Rodrigues, Hugo; Arêde, António; Varum, Humberto; Tavares, P.The behaviour of the infill masonry (IM) walls in the reinforced concrete (RC) buildings has been subject of numerous numerical and experimental studies with the main purpose of characterizingtheir influence in buildings' response under seismic loadings. Although being considered non-structural elements, during an earthquake this type of elements tends to interact with the reinforced concrete surrounding frames, which canresult in different types of in-plane damage, namely diagonal cracking, corner crushing, shear-friction failure which significantly reduce the out-of-plane performance of such type of elements. In order to studythe in-plane behaviourof IM walls and its interaction with the surrounding frames, a full scale experimental test involving a double leaf infill panelwas carried out in the Laboratory of Earthquake and Structural Engineering - LESE. In addition,aDigital Image Correlation (DIC) technique was used and to monitor the experimental test response aiming at validating the potential of DIC as a non-contact, full-field, optical tool to measure displacement fields of both in-plane (2D) and out-of-plane (3D) structural motions. DIC consists on recording images at different stages of a test, with dissimilar perspectives, by dividing them in small sections, or subsets, and tracking their displacements along the different captured images. This research paper presents the in-plane experimental test and the results of the DIC technique application.
- Developing an Enterprise Architecture Proof of Concept in a Portuguese HospitalPublication . Rijo, Rui; Martinho, Ricardo; Ermida, DiogoA Portuguese hospital with 700 beds and assisting 600 000 inhabitants, in its strategic plan, claimed for the urgent need of using new management approaches for dealing with the complexity of their information systems (IS), the highly coupled Information Technology (IT) infrastructures, and the inefficiency in the communication. This paper describes a proof of concept development using the concepts of Enterprise Architecture (EA) to contribute for a solution for these needs. The work focuses on the improvement of the medical appointment and patients' customer service business processes. Based on key points of existing EA frameworks, we started by using a questionnaire to the top management, and defining a common vision for this specific area, followed by the elicitation of the business processes and the supporting IS and IT infrastructures. Finally, we selected the key performance indicators that will help the hospital to monitor the performance of these processes. With this information gathered we offer a tool for top management to communicate with the clinical and IT areas and, together, take decisions with a common mind map and with the possibility to simulate the impact in the organization of those decisions. Another result of this work is the lessons learned in this proof-of-concept that can be applied in other areas and business processes of the hospital.
- Assessment of seismic strengthening solutions for existing low-rise RC buildings in NepalPublication . Chaulagain, Hemchandra; Rodrigues, Hugo; Spacone, Enrico; Varum, HumbertoThe main objective of this study is to analytically investigate the effectiveness of different strengthening solutions in upgrading the seismic performance of existing reinforced concrete (RC) buildings in Nepal. For this, four building models with different structural configurations and detailing were considered. Three possible rehabilitation solutions were studied, namely: (a) RC shear wall, (b) steel bracing, and (c) RC jacketing for all of the studied buildings. A numerical analysis was conducted with adaptive pushover and dynamic time history analysis. Seismic performance enhancement of the studied buildings was evaluated in terms of demand capacity ratio of the RC elements, capacity curve, inter-storey drift, energy dissipation capacity and moment curvature demand of the structures. Finally, the seismic safety assessment was performed based on standard drift limits, showing that retrofitting solutions significantly improved the seismic performance of existing buildings in Nepal.
- Fatigue strength of tubular carbon fibre composites under bending/ torsion loadingPublication . Capela, C.; Ferreira, J.A.M.; Febra, T.; Costa, J.D.Carbon fibre reinforced polymer composites have been increasingly used on structures frequently subjected to biaxial fatigue loadings. This paper studies the fatigue behaviour of tubular carbon fibre composites under in phase biaxial bending/torsion dynamic loadings. Particularly, it was analysed both the torsion stress and mean stress effects on the fatigue strength and failure mechanisms. Fatigue strength decreases significantly with increased torsional/bending stresses ratio, while the damage becomes faster. For the cases in which a torsion loading was applied the effect of the mean stress on the fatigue strength seems to be well fitted by using a quadratic equation.