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.
- 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.
- 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.
- 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.
- Estimation of prevalence in rare disease using pooled samplesPublication . Martins, J. P.; Santos, R.; Felgueiras, M.The use of pooled samples for screening infected individuals is a known procedure to reduce costs. In an estimation problem, the aim is only to determine how many individuals are infected instead of determining who is infected (classification problem). In that setting, our goal was to compare the performance of using one or two-dimensional arrays. The best performance was established according to one of the following criteria: minimizing the number of individuals or the number of tests required to attain a certain estimate accuracy. It is observed that when we want to minimize the number of individuals used, the two-dimensional procedures have a little advantage over the one-dimensional procedures. However, when the major concern is the cost, the one-dimensional procedures clearly outperform the two-dimensional procedures.
- A finite element method to study multimaterial wind towersPublication . Pascoal-Faria, P.; Dias, C.; Oliveira, M; Alves, N.Wind towers are used to produce electrical energy from the wind. A significant number of towers is manufactured using tubular separately steel or concrete, having limitations such as maximum diameter and height imposed essentially by transportation limitations. Developed computational studies on structural design of towers have been mainly focused on a single material. This investigation aims to develop a finite element method able to study structural design of wind towers combining different materials. The finite element model combines solid and shell elements encompassing different geometries. Several case studies are considered to validate the proposed method and accurate results are obtained.
- Hybrid channel-object approach for cinema post-production using particle systemsPublication . Fonseca, Nuno; Fonseca, NunoParticle systems are a new sound design approach that is receiving some attention from the cinema community due to the ability to handle thousands of sound sources simultaneously. Unfortunately, current immersive object-based audio formats are not prepared for such scale, forcing sound designers to use traditional channel-based audio approaches. This paper presents a hybrid approach that tries to merge the advantages of both object-based audio and channel-based audio. By using audio-objects with static positions, a high number of virtual "speaker channels" can be created, adding more space resolution than traditional channel-based formats, and allowing the mix of thousands of sounds. The proposed method can be used not only with particle systems software, but also on object-based audio down-mixing processes or even in high-demanding audio post-production workflows.
- Industrial Robot Trajectory Generation and Execution for 3D Printing using an ABB IRB 1200Publication . Cavalcanti, Marcella; Costelha, Hugo; Neves, CarlosThe use of industrial robots in additive manufacturing processes has become increasingly important, offering more flexibility and the capability of multi-directional printing. This integration facilitates the production of more complex geometries, free from the limitations of small build volumes and support structures, opening new possibilities for innovation in advanced manufacturing systems. As the complexity of the printed structures grows, optimizing robot trajectories is essential to ensure high-quality results. This work presents a comparative analysis of robot trajectory generation and execution using ABB's 3D Printing Power Pack and generated RAPID coding in both simulated and real environments. The objective is to assess the use of the Power Pack in term of trajectory accuracy and efficiency, as well as how the simulated results compare with the real ones, considering the use-case of 3D printing. To support this analysis, a "test pattern" was designed to account for different trajectories, consisting of a single line extrusion path featuring long linear segments, corners, and curved sections. The path was converted into both G-code and RAPID code. The G-code was first validated on a standard 3D printer and then used as input in the 3D Printing Power Pack application to generate a RAPID program for the robot. Separately, another RAPID program was created manually to execute the same path, based on the G-code. Both programs were executed on a simulated environment in RobotStudio, and on an ABB IRB 1200 robot. Throughout the tests, the robot’s Tool Center Point (TCP) position was captured using ABB’s Externally Guided Motion (EGM) application.
- Mechanical properties assessment for TPMS based scaffolds using homogenization methodsPublication . Pinheiro, J.; Castro, A. P. G.; Ruben, R. B.; Guedes, J. M.; Fernandes, P. R.The combination of computational methods with recent 3D printing technologies allows for the control of scaffolds microstructure, in order to obtain application-driven mechanical properties. Lately, geometries obtained using triply periodic minimal surfaces (TPMS) have been used to design porosity-controlled scaffolds for bone tissue engineering. The objective for this work is to assess the properties of TPMS scaffolds obtained using Schwartz P, Schwartz D and Gyroid, with different porosity levels. These properties are computed by an asymptotic homogenization method to obtain the effective permeability and stiffness. Results show that the obtained properties compare well with the properties of bone scaffolds presented in literature and obtained using different means.