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Valorisation of agricultural and mussel waste through the development of experimental diets and analysis of their effect on the growth of the polychaete Hediste diversicolor (O.F. Müller, 1776)
Publication . Teles, Diogo Miguel Carreiras; Pombo, Ana Margarida Paulino Violante; Baptista, Teresa Maria Coelho
The agriculture and aquaculture industries are essential for food production, but they also produce waste that can harm nearby ecosystems. Therefore, new strategies must be created and adopted to valorise the different types of waste produced by various industries, in line with the principles of the circular economy.
The polychaete Hediste diversicolor is a commercially valuable organism used as fishing bait and supplementary aquaculture feed. Furthermore, this species has been utilised by several researchers as a means of recycling waste from various species within the context of aquaculture production, as well as waste from biogas production. This study aimed to use H. diversicolor to transform two types of waste — olive oil production waste (wet olive pomace) and mussel production waste — into valuable biomass. To this end, two trials were conducted.
In the first trial, four diets with two different lipid compositions (6% and 12%) and sources (wet olive pomace and rapeseed oil) were tested directly on polychaetes. The second trial involved testing IMTA cultivation of this polychaete species alongside the mussel Mytilus edulis through three treatments involving different quantities of cells (1×107, 5×107 or 20×107 cells per individual) of Tetraselmis chuii and Chaetoceros gracillis (in a 50:50 ratio). At the end of both trials, the polychaetes from each treatment were captured and weighed to calculate their survival and growth parameters (SR, SGR, AGR, final biomass and mean wet weight).
In the first trial, the survival rate was similar for diets 2 and 4 (respectively 6% and 12% lipids, without wet olive pomace), but significantly lower for diet 3 (12% lipids and with wet olive pomace) compared to the other treatments (p-value < 0.05). The highest growth was observed in diet 2, and the diet with the worst results in relation to these parameters was treatment 3.
In the second trial, there were no high mortality rates in any treatment, and polychaete growth was higher in treatments (2 and 3) with greater amounts of food supplied to the bivalves, with most parameters being statistically higher than in treatment 1 (p-value < 0.05).
Thus, the first trial of this study concluded that wet olive pomace is not an ideal ingredient for a H. diversicolor diet. However, further testing of smaller amounts of this waste in polychaete diets would be necessary to better assess whether this is an effective method of treating this type of waste. The second trial concluded that the polychaete H. diversicolor could successfully feed on waste produced by M. edulis mussels, and that this type of IMTA has potential for mussel waste treatment, since treatment 3 (20 ×107 cells/ind.) produced good growth parameters.
Fatigue crack growth of TiAl6V4 parts produced by SLM under biaxial mode I/mode II loading
Publication . Borrego, L. P.; Jesus, J. S.; Ferreira, J. A. M.; Costa, J. D.; Capela, C.
Mode I and mixed-mode fatigue crack growth tests were performed using compact tension shear specimens made of Ti-6Al-4V by additive manufacturing for various loading angles. The accuracy of the methodology used to determine the equivalent stress intensity factor was studied, obtaining good results in a simpler method and particularly when the crack deflection angle was included in the algorithm. The crack growth speed did not suffer significant alterations due to similar values of crack deflection angle, mode I loading predomination and similar crack closure effect. Fractured surfaces presented irregular regions consequence of intergranular separation between β phase and agglomerations of α phase.
Tourist satisfaction: an analysis of tourists visiting historic centres in Portugal
Publication . Duque, Ana Sofia; Carvalho, Paulo; Almeida, Nuno
Achieving tourist satisfaction is one of the main goals of destinations, companies and managers in the field of tourism. To better understand this key concept, we have studied other associated constructs that we call antecedents and consequences, such as tourist motivations, quality of experience and loyalty to the destination. It was decided to achieve the proposed goals by conducting questionnaire surveys with nonresident tourists in Portugal over the three high tourist season months, which are regarded as June, July and August. The sample was collected in five of Portugal’s main historical centres, namely, Porto, Coimbra, Lisbon, Évora and Faro. With this study it was possible to confirm that the level of satisfaction of tourists, who visit historic centers in Portugal, is very high. It was also possible to verify the existing connection between the various constructs developed in the research, through the hypothesis test.
Assessment of existing rc precast industrial buildings according with eurocode 8 - part 3
Publication . Batalha, Nádia; Rodrigues, Hugo; Sousa, Romain; Varum, Humberto; Fernandes, Paulo
Precast reinforced concrete (PRC) buildings are common in the Portuguese industrial park, as well as throughout Europe. In past earthquakes, namely in Italy and Turkey, this typology of buildings showed a poor performance, namely at structural level. One of the major concerns at structural level regards the connection between the beams and columns. In recent surveys at the Portuguese industrial buildings, it was observed that the buildings built before 1980 present, most of the times, only friction connections between beam and columns. This type of connection is pointed as one of the weakest structural system in this typology of structures and consequently led to serious local and global damage when subjected to seismic loads. Regarding this issue, it was considered appropriate and necessary the study of existing Portuguese buildings with this type of beam-to-column connection and compare it with the use of mechanical connections (dowels), which is a more common solution in the recent buildings. The seismic behaviour of two PRC buildings built with these two solutions was analysed considering nonlinear static and dynamic analyses addressing both global and local (connections) response parameters. When analysed in view of the seismic regulation for existing buildings (Eurocode 8 –Part 3), the results obtained show that, overall, this typology of buildings present an acceptable structural performance. Nonetheless, unsatisfactory performance was observed at the beam-to-column connection in one of the buildings built without steel dowels. The results presented in this study highlight the need to consider adequate models to simulate these connections in order to accurately represent the seismic behaviour on the structure and identify possible limitations in the use of nonlinear static procedures to assess the seismic performance of this typology of buildings. In general, the buildings in study, located in a region of moderate seismicity, exhibited a satisfactory behaviour. However particular attention should be paid to beam-to-column connections, especially in the case of friction connections. In this regard it is important to accurately represent in the model the mechanisms involved in the connections, particularly in buildings located in moderate to high seismic zones.
Special Issue on the International Conference on Health and Social Care Information Systems and Technologies 2012
Publication . Cruz-Cunha, Maria Manuela; Rijo, Rui; Martinho, Ricardo
This special issue of the International Journal of Healthcare Information Systems and Informatics integrates the enhanced versions of a selection of papers submitted and presented at HCist’2012 - International Conference on Health and Social Care Information Systems and Technologies, held in Algarve, Portugal last October 2012. It was the second edition
of a conference where, under the leitmotiv of Healthcare Information Systems, academics, scientists, IT/IS professionals, managers and solution providers from all over the world had
the opportunity to share experiences, bring new ideas, debate issues and introduce the latest developments.