ESTG - Comunicações em conferências e congressos internacionais
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Percorrer ESTG - Comunicações em conferências e congressos internacionais por Objetivos de Desenvolvimento Sustentável (ODS) "12:Produção e Consumo Sustentáveis"
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- Alternative heavy tailed models in seismologyPublication . Felgueiras, Miguel; Martins, João; Santos, RuiGreat earthquakes are commonly considered as the ones with moment magnitude (Mw ) above or equal to 8.0. Since these earthquakes can destroy entire communities located near the epicentre, the search of physical laws that explain the energy released by them is an important issue. There is a connection between the radiated energy of an earthquake, its magnitude and its seismic moment (M 0). Thence, when fitting a heavy or an extremely heavy tailed distribution to a seismic moment dataset, we are in fact adjusting a mathematical model which explains the amount of energy released by these great seisms. Therefore, the main goal of this work is to study the more appropriated Pareto based models (the most used family in this field) when explaining the seismic moment of the great earthquakes. With this purpose in mind, we selected two different catalogs that accommodate recent events and are considered more accurate than other catalogs used in previous works. We conclude that the traditional Pareto distribution remains a good choice to deal with this kind of data, but Log-Pareto lead to higher p-values and Location-scale Pareto is better fitted to the biggest events.
- Assessment of existing rc precast industrial buildings according with eurocode 8 - part 3Publication . Batalha, Nádia; Rodrigues, Hugo; Sousa, Romain; Varum, Humberto; Fernandes, PauloPrecast 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.
- Biofuel for the energy efficiency on a building with small CCHPPublication . Galvão, João; Leitão, S.; Malheiro, S.; Gaio, T.This document reports the development of a technical and economical study related to the use of a renewable energy source - biomass for electricity and heat production. It is a hybrid and autonomous system with solar PV panels and environment friendly process aiming the reduction of energy demand, costs and emissions. This energy model is a new sustainable standard about efficiency consumption energy (electrical and thermal demands) of a small hotel building, with the biomass gasification cogeneration technology. This system is one relevant contribute to certify the building agree to the new national legislation of building thermal behaviour.
- Collaborative Vehicle Self-Localization Using Multi-GNSS Receivers and V2V/V2I CommunicationsPublication . Conde Bento, Luis; Chelim, Rafael; Nunes, UrbanoThis paper presents a collaborative self-localization approach using a multi-GNSS receiver setup and V2V/V2I communications. The purpose is to develop a low-cost alternative (equipment and installation), without compromising the process of localization estimation. The proposed method uses two GPS-receivers installed on the vehicle, disposed longitudinally on the cover (to maximize the distance among receivers) in order to estimate the Yaw and Pitch angles. To estimate the Roll angle, the proposed approach uses information from a receiver on the road infrastructure or on a nearby vehicle using V2V and/or V2I communication (compliant with 802.11p standard). Experimental results revealed that the performance on both absolute positioning and Pitch angle estimation is very high. The method is accurate in Yaw angle estimation enabling acceptable results in heading computation. Therefore the use of this algorithm in risk assessment on crossroads approaching scenarios, is achievable with an affordable setup. The Roll angle estimation can reach satisfactory results if there is a third receiver in the vicinity and in a non-collinear position with respect to the installed onboard receivers.
- Comparative Cases From Portuguese Social Innovation Public PolicyPublication . Ciccarino, Irene; Rodrigues, SusanaInnovation generally involves poorly structured problems, which do not have an obvious solution within the knowledge available. The solution is usually evolutionary, resulting from several attempts and refinements. Social innovation aims to address social problems and needs, which happen regardless of economic odds. This innovation can be an answer to a social need by embedded solutions and by different stakeholders' mobilization to sustain effective social change. It also can be about the best resource use or cost reduction, mainly the social ones. Portugal has developed a pioneer public policy to encourage entrepreneurship, social innovation and boost the social investment market. The Portugal Social Innovation Programme (PIS), links investors and social entrepreneurial initiatives (SEI) and offers support to structure SEI in a sustainable way by providing resources and network. Insofar SEIs accomplish the contracted results, PIS rewards their private investors. Thence public and private capital share risks, and the public capital is driven to the most effective initiatives. PIS enables the experimentation needed for innovation building and increases the chance of public services improvement, contributing to enhance the welfare-state. In this sense, this research goal is to describe three revealing cases of SEIs supported by PIS, highlighting innovation features and contextualizing theory. The data was collected by 3 semi-structured in-depth interviews which responses could be found in a database with 120 cases built by an online survey. The thematic content analysis was conducted applying codes from theory and PIS’s investment criteria. Then cases were compared to understand the outcomes of investment criteria and to examine theoretical features. The study discusses PIS investment criteria and presents SEIs types endorsed by it. Thus, it helps disclosure and stakeholders' expectations management. It also enables understanding the relationship between innovation, business model sustainability, and social value creation in the Portuguese context. The SEIs analyzed endorses PIS's innovative potential in building networks and foster the entrepreneurial ecosystem. This study also poses a new way to identify and compare different kinds of social values paving the way for a less subjective and tricky assessment routine.
- Comparison by computer fluid dynamics of the drag force acting upon two helmets for wheelchair racersPublication . Forte, P; Marinho, D. A.; Morouço, P; Pascoal-Faria, P.; Barbosa, T. M.The aim of this study was to compare the drag force created by two helmets (time trial and road)used by a wheelchair racer. The head and helmet of the racer were scanned to obtain the3D models. Numerical simulation was run on Fluent, having as output the drag force for both helmets (road and time trial) in two different positions (0º and 90º) and increasing velocities (from 2.0 to 6.5 m/s). The greatest aerodynamic drag was noted wearing a time trial helmet in 90º ranging from 0.1025N to 0.8475N; this was also the position with the highest drag. The velocity with higher drag for booth helmets was at 6.5 m/s. The time trial helmet at 0º had the lower aerodynamic drag, compared with the same position of road helmet. The drag force seems to be lower wearing the time trial helmet and keeping the 0º position and, thus, should be considered for sprinting events.
- Complexity control of HEVC through quadtree depth estimationPublication . Correa, Guilherme; Assunção, Pedro; Agostini, Luciano; Cruz, Luis A. da SilvaThe emerging HEVC standard introduces a number of tools which increase compression efficiency in comparison to its predecessors at the cost of greater computational complexity. This paper proposes a complexity control method for HEVC encoders based on dynamic adjustment of the newly proposed coding tree structures. The method improves a previous solution by adopting a strategy that takes into consideration both spatial and temporal correlation in order to decide the maximum coding tree depth allowed for each coding tree block. Complexity control capability is increased in comparison to a previous work, while compression losses are decreased by 70%. Experimental results show that the encoder computational complexity can be downscaled to 60% with an average bit rate increase around 1.3% and a PSNR decrease under 0.07 dB.
- Cyclic plastic behaviour of 7075 aluminium alloyPublication . Nogueira, F.; Cunha, J.; Mateus, A.; Malça, C.; Costa, J. D.; Branco, R.This paper aims at studying the cyclic plastic behaviour of the 7075-T651 aluminium alloy under fully-reversed strain-controlled conditions. Tests are conducted under strain-control mode, at room temperature, in a conventional servo-hydraulic machine, from smooth samples, using the single step method, with strain amplitudes (∆ε/2) in the range ±0.5 to ±2.75%. This material has exhibited a mixed behaviour, i.e. cyclic strain-hardens at higher strain amplitudes (∆ε/2/>1.1%) and cyclic strain-softens at lower strain amplitudes (∆ε/2<1.1%). A linear relationship between the degree of cyclic strain-hardening and the strain amplitude has been established for higher strain amplitudes. Fatigue-ductility and fatigue-strength properties agree with those found in the open literature for the same loading conditions.
- Effects of Scaffold Electrical Properties on Electric Field Delivery in BioreactorsPublication . Meneses, João; Fernandes, Sofia R.; Alves, Nuno; Pascoal-Faria, Paula; Miranda, Pedro CavaleiroIn tissue engineering, cell culture scaffolds have been widely used in combination with electrical stimulation to promote multiple cellular outcomes, like differentiation and proliferation. Nevertheless, the influence of scaffolds on the electric field delivered inside a bioreactor is often ignored and requires a deeper study. By performing numerical analysis in a capacitively coupled setup, this work aimed to predict the effects of the scaffold presence on the electric field, considering multiple combinations of scaffold and culture medium electrical properties. We concluded that the effect of the scaffold on the electric field in the surrounding culture medium was determined by the difference in electrical conductivity of these two materials. The numerical simulations pointed to significant variations in local electric field patterns, which could lead to different cellular outcomes and confound the interpretation of the experimental results.
- Energy Efficiency and Sustainability in an Aquaponic Greenhouse Supported by IoTPublication . Galvão, João; Santos, Pedro; Aires, Luis; Ribeiro, Vânia; Neves, FilipeThe increasing demand for agricultural crops and the necessity to reduce environmental impacts from traditional agriculture have led to the emergence of sustainable production systems such as hydroponics and aquaponics. These soil and pesticide-free systems require less water and fertilizers but need electrical energy and controlled greenhouse environmental conditions to be highly productive. This work presents a monitoring and management system for environmental parameters inside an aquaponic greenhouse, that allows the manager to assess in real-time the working status of the aquaponic system, helping in the detection of critical conditions that require a quick decision. This system was developed to measure, through IoT sensors network, the temperature and the relative humidity of the air, the temperature, pH and the electrical conductivity of the water that contains the dissolved nutrients that feed the growth of the plants. It is possible to visualize the measured parameters via the Internet, on a dashboard, in a mobile application and store these variables in a database. To further increase the sustainability of the aquaponic greenhouse, the electricity consumed during its activity will be produced locally by photovoltaic technology. The technologies proposed in this work may promote the emergence of small models of greenhouses, implemented by communities and populations, reducing production energy costs and transportation resources.