158 documents found, page 1 of 16
Data-driven insights to reduce uncertainty from disruptive events in passenger ...
Marques, L.; Moro, S.; Ramos, P.This study investigates the predictive modeling of the impact of disruptive events on passenger railway systems, using real data from the Portuguese main operator, Comboios de Portugal. We develop models using neural networks and decision trees, using key features such as the betweenness centrality indicator, railway track, time of day, and the train service group. Conclusively, these attributes significantly p...
Orientações Pedagógicas para Creche
Marques, A.; Azevedo, A.; Marques, L.; Folque, M. A.; Araújo, S.O direito à educação desde o nascimento implica a garantia de condições e oportunidades para todas as crianças, assumindo o compromisso com a educação para a equidade, a educação inclusiva e a educação integral. A educação em contextos de creche de qualidade constitui-se como oportunidade para as crianças construírem relações sociais positivas e desenvolverem sentimentos de pertença à família, à comunidade e à ...
Coercive field control in epitaxial ferroelectric Hf0.5Zr0.5O2 thin films by na...
Kim, Ji Soo; Strkalj, Nives; Silva, Alexandre Daniel Mendonça Faria; Lenzi, Veniero; Marques, L.; Hill, Megan O.; Yuan, Ziyi; Liu, Yi XuanThe discovery of ferroelectric hafnium oxide has spurred great interest in the semiconductor industry, enabled by its complementary metal-oxide-semiconductor compatibility and scalability. However, many questions remain regarding the origin of the ferroelectric phases and the tunability of ferroelectric properties. In this work, we explore the influence of laser fluence on coercive field (E<inf>c</inf>) in 10 n...
Ultra-sensitive, self-powered, CMOS-compatible near-infrared photodetectors for...
Silva, Nuno E.; Jayakrishnan, Ampattu R.; Kaim, Adrian; Gwozdz, Katarzyna; Domingues, Leonardo; Kim, J. S.; Istrate, Marian C.; Ghica, CorneliuSelf-powered near-infrared (NIR) photodetectors are essential for surveillance systems, sensing in IoT electronics, facial recognition, health monitoring, optical communication networks, night vision, and biomedical imaging. However, silicon commercial detectors need external power to operate and cooling to suppress large dark currents. This work demonstrates a new class of CMOS-compatible self-powered NIR phot...
Engineering Pb-free relaxor ferroelectric thin films for low voltage energy sto...
Ribeiro, Duarte J. M.; Nair, Surya Kiran Puravankara; Ravikumar, Jayakrishnan AMpattu; Oliveira, João; Magagnin, Grégoire; Albertini, DavidPulsed power technologies demand dielectric capacitors that possess a high energy storage density and efficiency at low applied electric fields/voltages. In this work, we engineered the morphology of lead-free \( 0.85[0.6\text{Ba}(\text{Zr}_{0.2}\text{Ti}_{0.8})\text{O}_3–0.4(\text{Ba}_{0.7}\text{Ca}_{0.3})\text{TiO}_3]–0.15\text{SrTiO}_3 \) (BZCT–STO) epitaxial thin films, fabricated using the pulsed laser dep...
Ab initio study of doping effects on the ferroelectric and piezoelectric proper...
Silva, Alexandre; Ganser, Richard; Silva, José Pedro Basto; Kersch, Alfred; Lenzi, Veniero; Marques, L.Ferroelectric binary oxides show great promise for application in energy storage, non-volatile memories, and neuromorphic computing devices. Compared to hafnia (HfO2), zirconia (ZrO2) thin films have been understudied in spite of significant recent progress. Doping has emerged as a promising tool to tune the ferroelectric properties of HfO2 and HfxZr1-xO2 (HZO). However, an extensive study of the effects of dop...
Growth of emergent simple pseudo-binary ferroelectrics and their potential in n...
Ravikumar, Jayakrishnan AMpattu; Kim, Ji S.; Hellenbrand, Markus; Marques, L.; MacManus-Driscoll, Judith L.; Silva, José Pedro BastoFerroelectric memory devices such as ferroelectric memristors, ferroelectric tunnel junctions, and field-effect transistors are considered among the most promising candidates for neuromorphic computing devices. The promise arises from their defect-independent switching mechanism, low energy consumption and high power efficiency, and important properties being aimed for are reliable switching at high speed, exce...
Robust multiferroicity and magnetic modulation of the ferroelectric imprint fie...
Zakusylo, Tetiana; Quintana, Alberto; Lenzi, Veniero; Silva, José Pedro Basto; Marques, L.; Yano, José Luís Ortolá; Lyu, Jike; Sort, JordiMagnetoelectric multiferroics, either single-phase or composites comprising ferroelectric/ferromagnetic coupled films, are promising candidates for energy efficient memory computing. However, most of the multiferroic magnetoelectric systems studied so far are based on materials that are not compatible with industrial processes. Doped hafnia is emerging as one of the few CMOS-compatible ferroelectric materials. ...
The benefits of incorporating lead-free ferroelectric materials in high energy ...
Jayakrishnan, Ampattu R.; Isfahani, Vahideh B.; Nair, Surya Kiran P.; Sekhar, Koppole C.; Marques, L.; Pereira, Mario; MacManus-Driscoll, Judith L.Demand for energy storage is increasing day by day and developing a pollution free environment necessitates new battery technologies. However, the existing energy storage technologies like lithium (Li)-ion batteries cannot fulfil the future needs alone. In this regard, Li-free batteries such as sodium (Na), potassium (K), zinc (Zn) and magnesium (Mg) ion batteries have attracted significant attention due to the...
Deep learning approach to the texture optimization problem for friction control...
Silva, Alexandre Daniel Mendonça Faria; Lenzi, Veniero; Pyrlin, Sergey; Carvalho, S.; Cavaleiro, Albano; Marques, L.The possibility to control friction through surface microtexturing can offer invaluable advantages in many fields, from wear and pollution reduction in the transportation industry to improved adhesion and grip. Unfortunately, the texture optimization problem is very hard to solve using traditional experimental and numerical methods, due to the complexity of the texture configuration space. Here, we apply machin...