306 documents found, page 1 of 31
New trends of additive manufacturing using materials based-on natural fibers an...
Ribeiro, J.E.; Rodríguez-Martín, Manuel; Barreiro, Joaquín; Fernández-Abia, Ana; García-Martín, Roberto; Rocha, João; Martínez-Pellitero, SusanaPolymeric materials based on natural fibers and minerals are currently being researched and their development is still in its infancy but is expected to increase in the coming years (being nowadays a hot topic). Their main advantage is that they make it possible to use waste and by-products of agricultural, forestry, and mineral origin to generate materials for Additive Manufacturing. Since their use reduces th...
2nd. International Workshop on Additive Manufacturing and Sustainability (IWAM)...
Rocha, João; Ribeiro, J.E.; Santos, Jorge; Lima, Rui A.In recent years, the manufacturing processes have undergone a profound transformation, driven by the rapid evolution of additive manufacturing (AM) technologies. What began as a tool primarily for prototyping through stereolithography has now expanded into a versatile and innovative field capable of producing functional, end-use components across a wide range of industries. From fused deposition modeling (FDM) ...
A conceptual design of multibus architectures for smart homes in residential DC...
Coelho, Sérgio; Rocha, João; Sepulveda, Manuel J.; Monteiro, Vítor Duarte Fernandes; Afonso, João L.Hand to hand with the ongoing energy transition, this paper proposes a conceptual multibus architecture for smart homes, designed to improve flexibility, efficiency, and scalability of residential DC microgrids. The proposed solution centralizes DC distribution at 800 VDC using the first conversion stage of a solid-state transformer (SST), while the subsequent two stages are allocated at the smart home level. I...
Design and Implementation of a DC–DC resonant LLC converter for electric vehicl...
Rocha, João; Amin, Saghir; Coelho, Sérgio; Rego, Gonçalo; Afonso, João L.; Monteiro, Vítor Duarte FernandesThis article presents the design and implementation of a DC–DC power converter for application in electric vehicle (EV) fast-charging systems. The prototype is of the resonant LLC type and consists of a high-power transformer operating at high frequency, which is an essential feature for the adequate behavior of the EV fast-charging system as a whole. As demonstrated throughout the article, by using this conver...
Variable DC-Link voltage for an LLC converter with wide input and output voltag...
Rocha, João; Amin, Saghir; Awais, Muhammad; Rego, Goncalo; Afonso, João L.; Monteiro, Vítor Duarte FernandesThis paper introduces an LLC converter with a variable input DC-link voltage, aimed to address the challenges of single stage DC-DC converter with wide output voltage range associated with electric vehicle (EV) fast chargers. The proposed design optimizes the input/output voltage ratio to enhance efficiency across a wide range of charging operating power values. The analysis highlights the converter's ability t...
Profiling external load in U14 basketball: Cluster analysis of competition perf...
Rocha, João; Serrano, João; López-Sierra; Ibáñez, SergioPhysical performance data is essential for planning youth training effectively; however, there is a lack of scientific information regarding performance in youth competitions. To address this gap, an innovative study was conducted with Portuguese U14 regional selections. Each player was equipped with a WimuPro™ inertial device. Six variables were considered: accelerations, decelerations, speed, player load, imp...
Análise comparativa da motricidade global e fina em crianças entre os 24 e os 4...
Adrião, Rafael; Rebelo, Miguel; Rocha, João; Farinha, Carlos; Silva Batista, Marco Alexandre; Serrano, JoãoEste estudo teve como objetivo comparar o desenvolvimento da motricidade global e fina em crianças entre os 24 e os 48 meses de idade, utilizando a bateria PDMS-2 como instrumento de avaliação. A amostra é composta por 193 crianças distribuídas em três grupos etários: 24 meses (N=22, 27.09±0.7 meses), 36 meses (N=78, 38.12±0.9 meses) e 48 meses (N=93, 49.45±1.1 meses). Foram analisadas as habilidades de Control...
A Comprehensive Review of Fused Filament Fabrication: Numerical Modeling Approa...
Enriconi, Maria; Rodriguez, Rocío; Araújo, Márcia; Rocha, João; García-Martín, Roberto; Ribeiro, J.E.; Pisonero, Javier; Rodríguez-Martín, ManuelFused Filament Fabrication (FFF) has become a widely adopted additive manufacturing technology due to its cost-effectiveness, material versatility, and accessibility. However, optimizing process parameters, predicting material behavior, and ensuring structural reliability remain major challenges. This review analyzes state-of-the-art computational methods used in FFF, which are categorized into four main areas:...
Optimization of Machining Parameters for the Fixed Pocket Cycle
Stein, Felipe Yukio Miyasaki; Giacomitti, Nickolas; Valério, Gustavo; Paulo, Jorge; Ribeiro, J.E.; Rocha, JoãoIn a competitive industrial setting, optimizing machining processes is important for enhancing surface quality and productivity. This study focuses on optimizing pocket milling parameters for 5083 H111 aluminum alloy using three toolpath strategies: Zig-Zag, Parallel Spiral, and One-Way. To achieve these goals, the Taguchi method, Grey Relational Analysis (GRA), ANOVA, and visual amplification were employed to ...
Experimental and Numerical Determination of Strain and Displacement Fields on B...
Ribeiro, J.E.; Rocha, JoãoThe Brazilian test is a straightforward method of indirect testing that consists of applying a diametrically opposite load to a circular disk to determine the tensile strength of brittle materials, namely rock, concrete, and rock-like material. The indirect tensile strength is commonly determined by assuming that failure takes place at the location of the highest tensile stress, specifically at the center of th...