Export 2127 results:
Sort by: Author Title Type [ Year  (Desc)]
2022
Almeida, Martim, Helena Mouriño, Arnaldo Batista, Sara Russo, Filipa Esgalhado, Catarina Palma R. dos Reis, Fátima Serrano, and Manuel Ortigueira. "Electrohysterography extracted features dependency on anthropometric and pregnancy factors." Biomedical Signal Processing and Control. 75 (2022).
Boavida, Nuno, Marta Candeias, and António B. Moniz The mechatronic training strategies to enable new skills for industry realignment towards industry 4.0: the case of Portugal. GERPISA 2022 Conference: The Automotive Industry Entering a Post-Pandemic World. Detroit: University of Michigan, 2022. Abstractgerpisa_2022_v6.pptx.pdf

The managerial strategies towards Industry 4.0 were coupled with the emergent normativity on incentive policies to enable automation improvements and industry realignment for new automotive value chains. In other words, the national framework to support company incentives for the concept of Industry 4.0 initiatives has pushed automotive industry managers to establish strategies of new investment on automation and repositioning in the global value chain.
Similarly, the scarcity of available qualifications for Industry 4.0, makes the share of "high road" jobs stable. The qualification process in the automotive industry has increased in parallel with the investment on automation.
An important contribution to this increase on job skills is significantly based on existing vocational training policies, which enable the incoming of higher skilled young job seekers, and a lifelong training and requalification of workers in the automotive sector. We have studied the training offer on “mechatronics” for the automotive sector, including both the manufacturing and repair activities. Data indicates a trend of increase of demand for mechatronic trained technicians with higher skills and preparedness for tasks related to automation, programming, maintenance and production control.
How about compensation? short- and long-term job stability? The young professionals that are seeking for a job in an OEM of the automotive sector, or even in a component provider in this sector, have higher probability and expectations of have better wage income and longer-term job stability due to his specialized skills. We have confirmed these results in our preliminary interviews with vocational training centres and company managers.
The managerial jobs are still privileged in the process realignment of industry, even in those case where the electrification technology tends to replace the ICE one. However, these cases are very limited in Portugal. Only Caetanobus and Mitsubishi-Daimler Fuso are producing electrical vehicles. The other OEMs are in a slower process of technological modernization. The choices over the application of principles of Industry 4.0 concept in their premises implied the recruitment of more jobs with the qualification on mechatronics, and managerial jobs to coordinate and control this technological transformation. In this sense, results do not support the conclusion that these managerial jobs are being eroded.
In parallel, there is an evolution of skills for specialized work clusters (automation, robotics, engine electrification). In our research we verified that the mechatronic trained young professionals are occupying jobs related to automation and robotics. But the skills related to the propulsion technologies based on electrification have a different requirement. Although, mechatronics is mostly related to Industry 4.0 strategy, it is expected that the energy transition will induce changes in the training contents of mechatronic. Some interviews also confirmed this trend. Thus, we can expect the emergence of two work clusters around a) Industry 4.0 competences and b) powertrain electrification.

Hendrickx, Christophe, Phil R. Bell, Michael Pittman, Andrew R. C. Milner, Elena Cuesta, Jingmai O'Connor, Mark Loewen, Philip J. Currie, Octávio Mateus, Thomas G. Kaye, and Rafael Delcourt. "Morphology and distribution of scales, dermal ossifications, and other non-feather integumentary structures in non-avialan theropod dinosaurs." Biological Reviews (2022). Abstracthendrickxetal.2021.morphologyanddistributionofscales.pdfWebsite

ABSTRACT Modern birds are typified by the presence of feathers, complex evolutionary innovations that were already widespread in the group of theropod dinosaurs (Maniraptoriformes) that include crown Aves. Squamous or scaly reptilian-like skin is, however, considered the plesiomorphic condition for theropods and dinosaurs more broadly. Here, we review the morphology and distribution of non-feathered integumentary structures in non-avialan theropods, covering squamous skin and naked skin as well as dermal ossifications. The integumentary record of non-averostran theropods is limited to tracks, which ubiquitously show a covering of tiny reticulate scales on the plantar surface of the pes. This is consistent also with younger averostran body fossils, which confirm an arthral arrangement of the digital pads. Among averostrans, squamous skin is confirmed in Ceratosauria (Carnotaurus), Allosauroidea (Allosaurus, Concavenator, Lourinhanosaurus), Compsognathidae (Juravenator), and Tyrannosauroidea (Santanaraptor, Albertosaurus, Daspletosaurus, Gorgosaurus, Tarbosaurus, Tyrannosaurus), whereas dermal ossifications consisting of sagittate and mosaic osteoderms are restricted to Ceratosaurus. Naked, non-scale bearing skin is found in the contentious tetanuran Sciurumimus, ornithomimosaurians (Ornithomimus) and possibly tyrannosauroids (Santanaraptor), and also on the patagia of scansoriopterygids (Ambopteryx, Yi). Scales are surprisingly conservative among non-avialan theropods compared to some dinosaurian groups (e.g. hadrosaurids); however, the limited preservation of tegument on most specimens hinders further interrogation. Scale patterns vary among and/or within body regions in Carnotaurus, Concavenator and Juravenator, and include polarised, snake-like ventral scales on the tail of the latter two genera. Unusual but more uniformly distributed patterning also occurs in Tyrannosaurus, whereas feature scales are present only in Albertosaurus and Carnotaurus. Few theropods currently show compelling evidence for the co-occurrence of scales and feathers (e.g. Juravenator, Sinornithosaurus), although reticulate scales were probably retained on the mani and pedes of many theropods with a heavy plumage. Feathers and filamentous structures appear to have replaced widespread scaly integuments in maniraptorans. Theropod skin, and that of dinosaurs more broadly, remains a virtually untapped area of study and the appropriation of commonly used techniques in other palaeontological fields to the study of skin holds great promise for future insights into the biology, taphonomy and relationships of these extinct animals.

Moreno-Azanza, Miguel, Manuel Pérez-Pueyo, Eduardo Puértolas-Pascual, Carmen Núñez-Lahuerta, Octávio Mateus, Blanca Bauluz, Beatriz Bádenas, and José Ignacio Canudo. "A new crocodylomorph related ootaxon from the late Maastrichtian of the Southern Pyrenees (Huesca, Spain)." Historical Biology (2022): 1-10. Abstracta_new_crocodylomorph_related_ootaxon_from_the_late_maastrichtian_of_the_southern_pyrenees_huesca_spain.pdfWebsite

ABSTRACTCrocodylomorph eggs and eggshells are known as old as the Late Jurassic and are frequent components of most multiootaxic eggshell assemblages. Classified within the oofamily Krokolithidae, thei histo- and ultrastructures are conservative throughout geological time, characterised by inverted-trapezoid-shaped shell units that grow from highly spaced basal knobs and present a diagnostic tabular ultrastructure. Here, we report 327 eggshell fragments from a new fossil site from the Maastrichtian of the Southern Pyrenees, Veracruz 1, and erect a new oogenus and oospecies, Pachykrokolithus excavatum oogen. et oosp. nov. characterised by crocodyloid morphotype and a prominent rugosocavate ornamentation. Eggshells from the slightly older locality of Blasi 2b, previously reported as aff. Krokolithidae, are also assigned to this new ootaxon. Different crocodylomorph taxa coexisted during the Late Cretaceous of the Tremp Basin, hindering the attribution of Pachykrokolithus excavatum oogen. et oosp. nov. to a single clade. Nevertheless, allodaposuchid eusuchians were dominant in this ecosystem, and are the most probable producers of Pachykrokolithus excavatum oogen. et oosp. nov. eggs.

Fernandes, AF, V. Beccari, AWA Kellner, and O. Mateus A new Gnathosaurine (Archaeopterodactyloidea, Pterosauria) from the Late Jurassic of Portugal. XIX Annual Conference of the European Association of Vertebrate Palaeontologists., 2022. Abstractfernandes_et_al_2022_pterosaur_eavp_2022_abstract_volume.pdf

n/a

Botelho, M. C., and H. Rocha O conhecimento do professor de matemática e a integração das tecnologias na sua prática. Atas do Encontro de Investigação em Educação Matemática., 2022.
Botelho, M. C., and H. Rocha O conhecimento profissional do professor de matemática na integração de diferentes tecnologias. Atas do XXXII Seminário de Investigação em Educação Matemática. Setúbal: APM, 2022.
Esgalhado, Filipa, Valentina Vassilenko, Arnaldo Batista, and Manuel Ortigueira. "On the Feasibility of Real-Time HRV Estimation Using Overly Noisy PPG Signals." Computers. 11 (12) (2022): 117.
Esgalhado, Filipa, Arnaldo Batista, Valentina Vassilenko, Sara Russo, and Manuel Ortigueira. "Peak Detection and HRV Feature Evaluation on ECG and PPG Signals." Symmetry. 6.14 (2022).
Boavida, Nuno, and António Brandão Moniz. "Perfil e representação de trabalhadores de plataformas digitais em Portugal." Sociologia: Revista da Faculdade de Letras da Universidade do Porto.Número Temático - Trabalho, plataformas digitais, cuidados: perspetivas pluridisciplinares (2022): 32-61. AbstractWebsite

O trabalho em plataformas digitais é uma nova forma de trabalho que, em Portugal, não tem ainda definido um modelo regulado de relações de trabalho. Este artigo analisa os perfis de trabalhadores de várias plataformas digitais de trabalho e a sua representação coletiva em Portugal. A diversidade encontrada nos estudos de caso dos perfis dos trabalhadores de cada plataforma explica, em parte, a falta de interesse de movimentos laborais em os representar. O tipo de tarefas e o local de trabalho contribuem para o desinteresse na procura de representantes coletivos, e demonstra os (des)alinhamentos que ocorreram entre trabalhadores e possíveis representantes. Observa-se ainda potencial para outros alinhamentos entre os interesses de diferentes trabalhadores, movimentos sindicais e associações de representação alternativa.

Kocadagli, Ozan, Ezgi Ozer, and Arnaldo G. Batista. "Preictal phase detection on EEG signals using hybridized machine learning classifiers with a novel feature selection procedure based GAs and ICOMP." Expert Systems with Applications (2022): 118825.
Şan, Mufit, Arnaldo Batista, Sara Russo, Filipa Esgalhado, Catarina Palma Reis, Fátima Serrano, and Manuel Ortigueira. "A Preliminary Exploration of the Placental Position Influence on Uterine Electromyography Using Fractional Modelling." Sensors. 5.22 (2022).
Esgalhado, F., A. Batista, V. Vassilenko, and M. Ortigueira. "Real-Time PPG-Based HRV Implementation Using Deep Learning and Simulink." Technological Innovation for Digitalization and Virtualization. Springer, Cham., 2022.
de Miguel, Pablo Sanz, António B. Moniz, Nuno Boavida, Joan Antoni Serra, M. Pańków, G. Karoulas, Marina Peliz, and I. Papageorgiou Social partners’ involvement in dual vocational education and training (VET): a comparison of Greece, Spain, Poland and Portugal. Barcelona: Notus, 2022. Abstractsocial_partners_involvement_in_dual_vocatioanl_education_and_training_vet._a_comparison_of_greece_spain_poland_and_portugal.pdfWebsite

The research report presents the key findings from the INVOLVE project (VS/2020/0145). It contributes to the debates on the participation of social partners in dual VET governance under countries generally classified as state-centred, skills-formation regimes (Spain, Greece, Portugal and Poland). The research report analysed the actual role played by social partners in the dual VET systems in the selected countries at different governance levels and the extent to which trade unions and employer organisations are involved on an equal footing. It also formulates policy recommendations supporting collective responses to dual VET systems in the selected countries. Findings are based on desk research, fieldwork consisting of semi-structured interviews and mini-case studies and national scenarios developed by INVOLVE partners, on the basis of a scenario workshop methodology

Karlovych, Oleksiy, and Eugene Shargorodsky. "Toeplitz operators with non-trivial kernels and non-dense ranges on weak Hardy spaces." Toeplitz Operators and Random Matrices. In Memory of Harold Widom. Operator Theory: Advances and Applications, vol. 289. Eds. Estelle Basor, Albrecht ¨Böttcher, and Torsten Ehrhardt. Birkhäuser, 2022. 463-476.
Moreno-Azanza, Miguel, Blanca Balauz, Lope Ezquerro, Rute Coimbra, Octávio Mateus, and Carmen Nuñez-Lahuerta. "Unbroken dinosaur eggs accumulated together do not guarantee autochthony of the fossil assemblage." Journal of Taphonomy. 16.1-4 (2022): 129-130. Abstractmoreno-azanza_et_al_2020_unbroken_eggs.pdf

n/a

Silva, Teresa P., Daniel de Oliveira, João P. Veiga, Vitor Lisboa, Jorge Carvalho, Alexandra M. Barreiros, Mathilda L. Coutinho, Eduardo Salas-Colera, and Rogério Vigário. "Contribution to the Understanding of the Colour Change in Bluish-Grey Limestones." Heritage. 5 (2022): 1479-1503. AbstractWebsite

Bluish-grey limestones have been extensively used as ornamental stones for decoration purposes in buildings, as well as in works of art, and accordingly, have been the target of intense exploration. In Portugal, the Jurassic limestone massif known as the Maciço Calcário Estremenho (MCE), has been the source of grey-coloured ornamental stones, namely the Azul Valverde (one of the most well-known bluish-grey limestones) and Atlantic Blue varieties, both of which may undergo colour changes in outdoor environments. In this sense, it is important to understand the sudden colour change from bluish-grey to yellow/beige in the same limestone block in a quarry, or even, what happens to the colour when polished limestone is placed outdoors. This study was undertaken using various techniques, namely XRF (X-ray fluorescence spectrometry), XRD (X-ray diffraction), SEM (scanning electron microscopy), DTA–TG (differential thermal analysis/thermogravimetry) and colourimetry. Synchrotron radiation was also used at the European Synchrotron Radiation Facility (ESRF, Grenoble, France) where XANES (X-ray Absorption Near Edge Structure) spectra at Fe K-edge were collected to ascertain the speciation state of Fe in different coloured zones of the limestone, previously checked by EDXRF (energy dispersive X-ray fluorescence). The presence of Fe2+ and Fe3+ are responsible for the greyish and yellow/brown colour, respectively. On the other hand, the UV radiation from the sun causes a quickened and severe bleaching/fading on the dark blue/grey polished limestone.

Zhou, H., W. - Y. Gao, H. C. Biscaia, X. - J. Wei, and J. - G. Dai. "Debonding analysis of FRP-to-concrete interfaces between two adjacent cracks in plated beams under temperature variations." Engineering Fracture Mechanics. 263 (2022). AbstractWebsite

Externally bonded fiber-reinforced polymer (FRP) composites have been widely used for the strengthening and repairing of reinforced concrete (RC) beams. Existing studies have denstrated that the full-range behavior and the associated debonding mechanism of the FRP-to-concrete interface between two adjacent cracks in the FRP-plated RC beam are different from those of the pull-off bonded joint. Moreover, the bond behavior between the FRP and the concrete may be affected by interfacial thermal stresses induced by the service temperature variations (i.e., the thermal loadings). Based on a fully reversible bilinear bond-slip model, this paper presents an analytical study to investigate the full-range deformation behavior of the FRP-to-concrete interface between two adjacent cracks under combined mechanical and thermal loadings. The analytical results have indicated that the thermal loadings may significantly influence the full-range deformation behavior and the axial stress distribution of the FRP plate, although the material properties of concrete, adhesive, and FRP are assumed to be not affected by the service temperature variations. A temperature increase leads to an increase in the ultimate load of the bond interface and vice versa. A finite element (FE) model with different considerations of the bondline damage is developed to verify the proposed analytical solution. The reliability of the proposed analytical solution is then validated by the comparisons between the analytical results and the corresponding predictions provided by the FE model. © 2022 Elsevier Ltd

Muttoni, A., D. Coronelli, M. Lamperti Tornaghi, L. Martinelli, I. R. Pascu, A. Pinho Ramos, G. Tsionis, P. Bamonte, B. Isufi, and A. Setiawan. "Deformation capacity evaluation for flat slab seismic design." Bulletin of Earthquake Engineering. 20 (2022): 1619-1654. AbstractWebsite
n/a
Zhang, S. S., Y. Ke, E. Chen, H. Biscaia, and W. G. Li. "Effect of load distribution on the behaviour of RC beams strengthened in flexure with near-surface mounted (NSM) FRP." Composite Structures. 279 (2022). AbstractWebsite

Debonding failures of FRP have been frequently observed in laboratory tests of reinforced concrete (RC) beams flexurally-strengthened with near-surface mounted (NSM) fibre-reinforced polymer (FRP). A number of numerical and theoretical studies have been carried out to predict debonding failures in NSM FRP-strengthened beams, and several strength models have also been proposed. The existing studies, however, were all based on the scenario of a simply supported beam tested under one or two-point loading, while the influence of load distribution has not yet been investigated. This paper presents the first ever study into the effect of load distribution on the behaviour of NSM FRP-strengthened RC beams. A series of large-scale RC beams flexurally-strengthened with NSM FRP strips were first tested under different load uniformities; then a finite element (FE) model, which can give close predictions to the behaviour of such strengthened beams, was developed; finally, the proposed FE model was utilized to investigate the influence of bond length of NSM FRP on the load uniformity effect. It was found that the load uniformity has a significant effect on the beam behaviour, and the degree of this effect varies with the bond length of NSM FRP. © 2021 Elsevier Ltd

Biscaia, H. C., and R. Micaelo. "Emerging anchored FRP systems bonded to steel subjected to monotonic and cyclic loading: A numerical study." Engineering Fracture Mechanics. 261 (2022). AbstractWebsite

Recently, the study of the bond behaviour of hybrid joints has increased due to their application in different industries. Their main purpose is to obtain lightweight but strong, durable structures. In addition, in some industries such as the automotive industry, those requirements may facilitate the construction of vehicles that have lower carbon dioxide emissions. Although the knowledge on the bond behaviour of hybrid bonded joints under monotonic loading is sufficient, the knowledge on the cyclic bond behaviour needs to be improved. The present work aims to mitigate that gap by proposing a numerical model in which the cyclic bond performance between a Carbon Fiber Reinforced Polymer (CFRP) bonded to a steel substrate can be analysed. The results provided by the Externally Bonded Reinforcement (EBR) are used as reference data. These other simulated bonding techniques cover cases where the CFRP is anchored to the substrate in different ways, which are becoming more popular, namely by: (i) linearly increasing the width of the CFRP; (ii) using the mixed adhesive concept (two solutions were considered); (iii) using a steel plate on top of the CFRP strip; and (iv) assuming no interfacial slips at the CFRP unpulled end, which is intended to simulate a perfect anchorage. Compared to the simulations carried out under monotonic loading, the simulations with the adopted cyclic loading history (loading/unloading cycles), allowed us to observe a degradation of the bond strength of the joints with the number of cycles. However, if the overlapped bonded joint is long enough, the strength of the CFRP-to-steel joints is not affected. Excluding the numerical specimens with the perfectly anchored CFRP, i.e. with an “ideal” anchorage, the length of the other adopted anchorages affected either the strength or the ductility of the joint, whether subjected to a monotonic or to the adopted cyclic loading protocol. © 2022 Elsevier Ltd

Azevedo, A. S., J. P. Firmo, J. R. Correia, C. Chastre, H. Biscaia, and N. Franco. "Fire behaviour of CFRP-strengthened RC slabs using different techniques – EBR, NSM and CREatE." Composites Part B: Engineering. 230 (2022). AbstractWebsite

This paper presents an experimental study about the fire behaviour of reinforced concrete (RC) slabs strengthened with carbon fibre reinforced polymer (CFRP) strips, applied according to three different techniques: externally bonded reinforcement (EBR); near-surface mounted (NSM), and continuous reinforcement embedded at the ends (CREatE), a new technique that prevents premature CFRP debonding. The main goals of this study were three-fold: to understand and compare the fire behaviour of the strengthening techniques, namely the CREatE technique (yet to be studied); to assess the efficiency of the fire protection schemes (constant thickness vs. increased thickness at the CFRP anchorage zones) in extending the fire resistance of the CFRP systems; and, based on the experimental results and data available in the literature, to propose “critical” temperatures for the fire design of CFRP-strengthened RC members. The results obtained show that: (i) without protection, the CREatE technique presented higher fire resistance than the alternative NSM and EBR techniques (24 min vs. 16 min and 2 min); (ii) with fire protection, regardless of its geometry, the NSM and CREatE techniques presented a similar fire resistance (both above 120 min), higher than the EBR technique (less than 60 min); and (iii) the “critical” temperatures for each technique were defined as 1.0Tg, 2.5Tg and 3.0Tg for EBR, NSM and CREatE, respectively, with Tg being the glass transition temperature of the adhesive, defined based on the onset of the storage modulus curve decay from dynamic mechanical analysis. © 2021 Elsevier Ltd

Pereira, \{Maria Elias\}, Jonas Deuermeier, Cátia Figueiredo, Ângelo Santos, Guilherme Carvalho, \{Vítor Grade\} Tavares, Rodrigo Martins, Elvira Fortunato, Pedro Barquinha, and Asal Kiazadeh. "Flexible Active Crossbar Arrays Using Amorphous Oxide Semiconductor Technology toward Artificial Neural Networks Hardware." Advanced Electronic Materials. 8 (2022). Abstract

Memristor crossbar arrays can compose the efficient hardware for artificial intelligent applications. However, the requirements for a linear and symmetric synaptic weight update and low cycle-to-cycle (C2C) and device-to-device variability as well as the sneak-path current issue have been delaying its further development. This study reports on a thin-film amorphous oxide-based 4×4 1-transistor 1-memristor (1T1M) crossbar. The a-IGZO crossbar is built on a flexible polyimide substrate, enabling IoT and wearable applications. In the novel framework, the thin-film transistor and memristor are fabricated at the same level, with the same processing steps and sharing the same materials for all layers. The 1T1M cells show linear and symmetrical plasticity characteristic with low C2C variability. The memristor performs like an analog dot product engine and vector–matrix multiplications in the 4×4 crossbars is demonstrated experimentally, in which the sneak-path current issue is successfully suppressed, resulting in a proof-of-concept for a cost-effective, flexible artificial neural networks hardware.

Yang, Y., J. Zhao, S. Zhang, Z. Yang, and H. Biscaia. "Influence of salt fog and ambient condition exposure on CFRP-to-steel bonded joints." Composite Structures. 280 (2022). AbstractWebsite

In this paper, the influence of salt fog and ambient condition exposure on CFRP-to-steel bonded joints (CSJs) with a near end mechanical anchorage was studied. The tests of the CSJs were carried out with a monotonic loading history respectively with and without a near end mechanical anchorage both unaged and after being exposed to the ageing conditions. The results revealed failures in the adhesive for some CSJs with a near end mechanical anchorage, among which also exhibited the best bond performance both in aged and unaged specimens. Due to the high state of degradation after ageing exposure, local damage of the CFRP located at the gap position of the CSJs was induced by a torsion action during the fixation of the specimen in the tensile machine even prior to the testing, which caused, although locally, severe delamination of the CFRP of the aged CSJs. From the torsion test results, a decrease in the torsional capacity of the CFRP after aging revealed the degradation of the carbon fiber-to-matrix interface. Additional results reflected that a drop in the initial stiffness of the load vs. slip relationship can be observed, caused by a pre-crack with a length of 30 mm in the CSJs. © 2021 Elsevier Ltd

Biscaia, H. C., M. S. Carvalho, A. P. Martins, and R. Micaelo. "Interfacial failure of circular or tubular hybrid bonded joints: A theoretical description." Engineering Failure Analysis. 132 (2022). AbstractWebsite

In different industries, the bonding technique has gained several advances in recent years. However, due to the specificity of each industry, the bonded joints may present different configurations. For instance, in the case of metallic truss bridges, the use of Carbon Fibre Reinforced Polymers (CFRP) bonded on the steel surface members may require circular or even tubular transitions between these materials. Although the bonded transitions between a metal and a composite material have been deeply studied with flat surfaces the information on circular or tubular hybrid bonded joints is still scarce. Therefore, the present study aims to mitigate some of this lack of knowledge by proposing an analytical solution able to describe the interfacial debonding process between a circular or tubular bonded transition between two materials. The proposed model also aims to simulate the interfacial debonding of double butt (or stepped) lap joints. Under these circumstances, a bilinear local adhesive model is adopted which required the quantification of the elastic and the softened stiffnesses as well as the pure Mode II fracture energy. The Finite Element Method (FEM) is used for the validation of the proposed model. The behaviour of the adhesive joint between materials is numerically modelled through the Cohesive Zone Modelling (CZM) in which the same bilinear shape used in the analytical solutions is adopted. Different situations were analyzed thoroughly and the numerical simulations tracked very closely the analytical results obtained from the proposed closed-form solutions. © 2021 Elsevier Ltd