Export 2127 results:
Sort by: Author Title Type [ Year  (Desc)]
2017
Biscaia, Hugo C., Carlos Chastre, David Cruz, and André Viegas. "Prediction of the interfacial performance of CFRP laminates and old timber bonded joints with different strengthening techniques." Composites Part B: Engineering. 108 (2017): 1-17. AbstractWebsite

Fiber Reinforced Polymers (FRP) is a recent technique to strengthen timber structures and the studies available discussing the debonding between these materials are limited. Therefore, the bond assessment between FRP composites and timber substrates is a topic that needs clarification. The present work analyses the debonding process between Carbon (C) FRP laminates and timber with rupture modes consistent with Mode II interfacial fracture, i.e. with the sliding mode where the bond stresses act parallel to the plane of the bonding surface. Several single-lap shear tests were performed and the experiments showed a nonlinear local behaviour of the CFRP-to-timber interface. An interfacial bond-slip model and its calibration procedure were also presented. Furthermore, the calibrated nonlinear bond-slip model was implemented in a numerical approach where the FRP composite and the adhesive are simulated by linear and nonlinear springs and the substrate is assumed rigid. The following influences on the debonding process of the CFRP-to-timber interface were also analysed: (i) the bonding technique (Externally Bonded Reinforcement - EBR; and Near Surface Mounted - NSM); and (ii) the use of an additional device to mechanically anchor the CFRP laminate. Besides the determination of the effective bond length for each bonding technique, a new concept defining the length beyond which the force at the anchorage device does not decrease with the bonded length and a proposal to estimate its value for any bonded length was also presented and discussed. The experimental tests have shown that the NSM technique has a better performance compared to the EBR technique, independently of the installation of mechanical anchorage devices. In the case of the EBR technique, the strains in the CFRP laminate increased at its vicinities due to the clamping force applied to the anchors, which affected the final strength of the interface.

Mota, B., A. Carvalho, M. I. Gomes, and A. P. Barbosa-Póvoa Sustainable supply chain design and planning: the importance of life cycle scope definition. Computer Aided Chemical Engineering, 40. Barcelona, Spain: Elsevier, 2017.
Russo, João, Octávio Mateus, Marco Marzola, and Ausenda Balbino. "Two new ootaxa from the late Jurassic: The oldest record of crocodylomorph eggs, from the Lourinhã Formation, Portugal." PLOS ONE. 12 (2017): 1-23. Abstractrusso_et_al_2017_two_new_ootaxa.pdfWebsite

The Late Jurassic Lourinhã Formation is known for its abundant remains of dinosaurs, crocodylomorphs and other vertebrates. Among this record are nine localities that have produced either dinosaur embryos, eggs or eggshell fragments. Herein, we describe and identify the first crocodiloid morphotype eggs and eggshells from the Lourinhã Formation, from five occurrences. One clutch from Cambelas, composed of 13 eggs, eggshell fragments from Casal da Rola and Peralta, one crushed egg and eggshells from Paimogo North, and four crushed eggs as well as eggshell fragments from Paimogo South. We observed and confirmed diagnostic morphological characters for crocodiloid eggshells and which are consistent with a crocodylomorph affinity, such as the ellipsoidal shape, wedge-shaped shell units, triangular extinction under cross-polarized light, and tabular ultrastructure. This material is distinctive enough to propose two new ootaxa within the oofamily Krokolithidae, Suchoolithus portucalensis, oogen. and oosp. nov., for the material from Cambelas, the most complete clutch known for crocodiloid eggs, and Krokolithes dinophilus, oosp. nov., for the remaining material. These are the oldest crocodylomorph eggs known, extending the fossil record for this group to the Late Jurassic. Furthermore, except for the clutch from Cambelas, the material was found with theropod eggs and nests, in the other four occurrences, which seem to suggest some form of biological relationship, still unclear at this point.

Biscaia, Hugo C., Carlos Chastre, and Manuel A. G. Silva. "Analytical model with uncoupled adhesion laws for the bond failure prediction of curved FRP-concrete joints subjected to temperature." Theoretical and Applied Fracture Mechanics. 89 (2017): 63-78. Abstract

The strengthening of structures such as columns, beams, arches or slabs with Fibre Reinforced Polymers (FRP) has been the focus of several studies. However, the studies dedicated to the FRP debonding phenomenon of curved bonded joints affected by elevated temperatures are surprisingly limited and no studies on this topic are known, at present, to use nonlinear analytical or numerical approaches. Still, the available studies found in the literature are unanimous in affirming that the debonding phenomenon on such curved interfaces demands the interaction between Fracture Modes I and II. The present work aims to develop an analytical solution capable of simulating the debonding process of curved CFRP-toconcrete interfaces with a constant radius subjected to mechanical and/or thermal loads. Some examples are presented in which the influence of the radius of the interface and the temperature level is analysed. The analytical solution proposed here is based on adhesion laws in which, in the case ofMode II, an exponential bond vs. relative displacement law with temperature dependency is assumed, whereas the Mode I adhesive law is based on a linear with fragile rupture law with the same temperature dependency as Mode II.

Brás, C. P., A. Fisher, J. J. Júdice, K. Schönefeld, and S. Seifert. "A block active set algorithm with spectral choice line search for the symmetric eigenvalue complementarity problem." Applied Mathematics and Computation. 294 (2017): 36-48. AbstractWebsite

In this paper, we address the solution of the symmetric eigenvalue complementarity problem (EiCP) by treating an equivalent reformulation of finding a stationary point of a fractional quadratic program on the unit simplex. The spectral projected-gradient (SPG) method has been recommended to this optimization problem when the dimension of the symmetric EiCP is large and the accuracy of the solution is not a very important issue. We suggest a new algorithm which combines elements from the SPG method and the block active set method, where the latter was originally designed for box constrained quadratic programs. In the new algorithm the projection onto the unit simplex in the SPG method is replaced by the much cheaper projection onto a box. This can be of particular advantage for large and sparse symmetric EiCPs. Global convergence to a solution of the symmetric EiCP is established. Computational experience with medium and large symmetric EiCPs is reported to illustrate the efficacy and efficiency of the new algorithm.

Cain, Alan J., and António Malheiro. "Combinatorics of Cyclic Shifts in Plactic, Hypoplactic, Sylvester, and Related Monoids." Combinatorics on Words: 11th International Conference, WORDS 2017, Montréal, QC, Canada, September 11-15, 2017, Proceedings. Eds. Srečko Brlek, Francesco Dolce, Christophe Reutenauer, and Élise Vandomme. Cham: Springer International Publishing, 2017. 190-202. Abstract

The cyclic shift graph of a monoid is the graph whose vertices are elements of the monoid and whose edges link elements that differ by a cyclic shift. For certain monoids connected with combinatorics, such as the plactic monoid (the monoid of Young tableaux) and the sylvester monoid (the monoid of binary search trees), connected components consist of elements that have the same evaluation (that is, contain the same number of each generating symbol). This paper discusses new results on the diameters of connected components of the cyclic shift graphs of the finite-rank analogues of these monoids, showing that the maximum diameter of a connected component is dependent only on the rank. The proof techniques are explained in the case of the sylvester monoid.

Cardoso, Tiago, João Sousa, and José Barata. "Digital Games Development Model." EAI Endorsed Transactions on Serious Games. 4.12 (2017): e2. Abstract

Nowadays technology follows us everywhere. However, it is often overlooked when dealing with social issues, despite how easily it might improve the life of countless handicapped individuals. In other words, small pieces of software, under the form of games, can help the individual remain focus and go through treatments and therapies effortlessly. But game development is tricky because simply adopting a software development approach is not enough, as it assumes that games as a software can be developed through the commonly used systematic processes, yet these do have specific requirements. This paper proposes a new game development model to successfully deliver a quality serious game, towards social causes, bearing in mind the specific aspects both from games as a special kind of software and from the target players introducing a therapeutic/clinical perspective in the games development model.

Wisniewski, Remigiusz, Grzegorz Bazydlo, Luís Gomes, and Anikó Costa. "Dynamic Partial Reconfiguration of Concurrent Control Systems Implemented in {FPGA} Devices." {IEEE} Trans. Industrial Informatics. 13 (2017): 1734-1741. AbstractWebsite

n/a

Baumann, Manuel, António B. Moniz, and Marcel Weil Energy storage systems in the future German electricity system: A literature review and expert interviews based foresight approach. Pensar o Futuro, Preparar a Mudança [To Think the Future, To Prepare Change]. Évora: CICS.NOVA/Universidade de Évora, 2017. Abstract

Germany has ambitious targets to produce 35 % of the needed electricity from Renewables (RES) mainly based on wind and solar power by 2020 and over 80 % by 2050 within the so called “Energiewende”. Energy storage is seen as a potential option to assure the safe RES system integration to achieve this goals. There is a high uncertainty and the resulting public discourse about the future demand of different storage technologies is driving further development of these technologies. A literature review of 9 studies and 10 expert interviews is carried out in line of a foresight exercise to tackle these uncertainties. The estimations of reviewed literature are based on models with a market perspective on energy storage demand. Most scenarios used in this models are built on top down logics, where processes at lower levels (technology, micro-economic sphere) are determined by dominant macro dynamics. Different storage technologies are only considered partially or in an aggregated way. The reviewed studies show that there is a high for potential storage on every time scale starting from the year 2030 to 2040. Analysed potentials vary depending on RES diffusion scenarios and excess rate assumptions which are estimated to be between 0 to 44 GW in 2050. Reviewed studies strongly integrate shared visions about system developments and formal analyses and provide important and valuable information about potential future implications regarding energy storage. But they only partially account, due to practical reasons, wider benefits, stakeholder opinions and continuous market and system changes. It is also not possible to account for discontinuities in the technological innovation process of energy storage within this quantitative approaches. Stakeholder interviews provide thus additional and helpful insights to the literature review. The stakeholders frame alternative potential future developments that could influence the market success and need for energy storage until 2050. Most important factors named where policy measures, new market models and decentralization of the energy system. As in literature there is a big uncertainty among experts about the importance of different storage technologies and if energy storage is in general the best option among other flexibility measures as grid reinforcement, flexible demand and flexible power plants. It remains thus impossible to provide suggestions regarding the development of single storage technologies.

Maia, L. B., I. Moura, and JJG Moura. "EPR spectroscopy on mononuclear molybdenum-containing enzymes." Future Directions in Metalloprotein and Metalloenzyme Research, Biological Magnetic Resonance, Vol. 33 (ISBN: 978-3-319-59100-1). Eds. G. Hanson, and LJ Berliner. Vol. 12. Cham: Springer Publishers, 2017. 100-130. Abstract

The biological relevance of molybdenum was demonstrated in the early 1950s-1960s, by Bray, Beinert, Lowe, Massey, Palmer, Ehrenberg, Pettersson, Vänngård, Hanson and others, with ground-breaking studies performed, precisely, by electron paramagnetic resonance (EPR) spectroscopy. Those earlier studies, aimed to investigate the mammalian xanthine oxidase and avian sulfite oxidase enzymes, demonstrated the surprising biological reduction of molybdenum to the paramagnetic Mo5+. Since then, EPR spectroscopy, alongside with other spectroscopic methods and X-ray crystallography, has contributed to our present detailed knowledge about the active site structures, catalytic mechanisms and structure/activity relationships of the molybdenum-containing enzymes.
This Chapter will provide a perspective on the contribution that EPR spectroscopy has made to some selected systems. After a brief overview on molybdoenzymes, the Chapter will be focused on the EPR studies of mammalian xanthine oxidase, with a brief account on the prokaryotic aldehyde oxidoreductase, nicotinate dehydrogenase and carbon monoxide dehydrogenase, vertebrate sulfite oxidase, and prokaryotic formate dehydrogenases and nitrate reductases.

http://docentes.fct.unl.pt/lblm/files/epr_book-chap_4.pdf

Versteeg, T., M. Baumann, Marcel Weil, and António Moniz. "Exploring emerging battery technology for grid-connected energy storage with Constructive Technology Assessment." Technological Forecasting and Social Change. 115 (2017): 99-110. AbstractWebsite

The last decades have shown an increasing amount of research into expectations of science and technology. Especially for emerging technologies, expectations held by different stakeholder are guiding the direction of research and development. In this article the results of an investigation into the expectations of specific actors regarding the development of emerging battery technology for applications in the power grid are presented. It is set up as an explorative study within the framework of Constructive Technology Assessment (CTA). A number of studies since the 1990s have indicated a growing need for energy storage options in the power grid, where batteries appear to be capable of providing a range of valuable services to the grid. Cost-effectiveness on a large scale will however require considerable technical improvements. The configuration of energy storage may differ in the specific location and exploitation of the storage assets, as well as in the investments in new storage capacity. In this study the visions and expectations of several relevant actors are analysed using interviews and surveys in terms of expectations of technological development, expectations concerning stakeholder roles, and channels of interaction between the relevant actors. The results indicate a divide in expectations between the user side of the technology (the electric power industry) and the development side (academic researchers). Opinions differ with respect to the obstacles to technological development, the actors relevant in early technological development, and the most suitable channels for interaction between these actors. It follows from the theoretical background that conflicts in expectations provide the opportunity for the acceleration of technological development and adoption through stakeholder participation. Small interactive workshops, where conflicts identified in this paper are discussed, were identified as a suitable channel in order to reach consensus in visions and expectations for battery technology.

Bini, Dario, Torsten Ehrhardt, Alexei Yu. Karlovich, and Ilya M. Spitkovsky(eds.) Large Truncated Toeplitz Matrices, Toeplitz Operators, and Related Topics. The Albrecht Böttcher Anniversary Volume. Basel: Birkhäuser Basel, 2017.Website
Correia, T., L. Barcelos, T. Nunes, D. Riff, and O. Mateus On a titanosaur scapula from the Marília Formation (Upper Cretaceous, Bauru Group) in Campina Verde Town. XXV Congresso Brasileiro de Paleontologia Boletim de Resumos., 2017. Abstractthiago_abstract_brazil_2017.pdf

n/a

Batista, Arnaldo Pregnancy Monitoring Using Uterine Electromyography: The Uterine Explorer Toolbox. Signal Processing and Monitoring in Labour (SPaM). Oxford, 2017.
Babo, A., and H. Rocha. "Problem solving in linear programming: a study in a vocational course - Resolução de problemas de Programação Linear: um estudo no ensino profissional." Revista de Estudios e Investigación en Psicología y Educación. E.1 (2017): 41-46. Abstract

The development of meaningful learning becomes possible when students are actively involved in solving real problems. Thus, this study intends to investigate how students of the 11th grade of a vocational course solve problems of Linear Programming, using the graphing calculator. The conclusions reached indicate that: the interpretation of the conditions of the problems is the most delicate point; the graphical approach using technology is dominant; and the difficulties raised by the problem as well as the need to discuss the results achieved are the basis for the interactions both among the students and between them and the teacher.

Chastre, Carlos, Hugo Biscaia, and Noel Franco. "Reforço de Vigas de Betão Armado com Armaduras Pós‑Instaladas de Aço Inox ou de Compósitos de FRP." Mecânica Experimental. 28 (2017): 39-46. AbstractWebsite

Neste artigo apresentam-se e analisam-se um conjunto de ensaios realizados em vigas de betão armado reforçadas com armaduras pós-instaladas de aço ou de FRP, incluindo os referentes a uma nova técnica (CREatE) desenvolvida na FCT NOVA. Os resultados experimentais permitiram concluir que a técnica CREatE possibilita aumentos de resistência e ductilidade consideráveis face às técnicas tradicionais.

Silva, TP, D. P. S. Oliveira, M. J. Batista, JP Veiga, F. Noronha, and J. X. Matos. "Rhenium ocurrence in Portugal: an overview considering the valorisation of mineral resources." Rhenium, Properties, Uses and Occurrences. Ed. Eric James. New York: Nova Science Publishers Inc. New York, 2017. 85-116.
Singh, Shreya, Pydi Bahubalindruni, and Joao Goes A robust fully-dynamic residue amplifier for two-stage SAR assisted pipeline ADCs. IEEE International Symposium on Circuits and Systems (ISCAS’17). Baltimore, USA: IEEE, 2017.
Gonçalves, J., M. I. Gomes, M. Fonseca, T. Teodoro, P. Pita Barros, and M. A. Botelho. "Selfie ageing index: an index for the self-assessment of healthy and active ageing." Frontiers in Medicine. 4.236 (2017).2017_goncalvesgomes_et_al_frontiersinmedicine.pdf
Sallem, Amin, and Pedro Pereira. "Sensitivity Analysis in the Optimization of Analog Active Filters by Applying the Richardson Extrapolation." Focus on Swarm Intelligence Research and Applications. Eds. Bachir Benhala, Pedro Pereira, and Amin Sallem. Nova Science Publishers, 2017. 247-275. Abstract

The key step of the analog active filter design is the optimal selection of component values due to manufactured series (E12, E24, E48, E96 and E192). In this paper, four simulation-based metaheuristics are applied to optimize four active filters using commercials available ICs as building blocks. The emphasis of this work is applying Richardson extrapolation-based sensitivity analysis in the optimization process of analog active filters. Indeed, Richardson extrapolation technique facilitates the calculation of the partial derivatives for the sensitivity using the simulation-based evaluation, without an explicit mathematical expression. Viability and benefits of the sensitivity analysis are highlighted. Monte Carlo analysis is performed in order to investigate robustness of the proposed sensitivity analysis of the active filters in case of component value variations due to specified tolerances of manufactured series.

Batista, Arnaldo, and André Pereira Software Development for the Detection and Characterization of Rail Corrugation. Workshop on Railway Track Dynamics. Caparica Campus, 2017.
Samanta, Smrutilekha, Bhawna Tiwari, Pydi Ganga Bahubalindruni, Pedro Barquinha, and João Goes. "Threshold voltage extraction techniques adaptable from sub-micron CMOS to large-area oxide TFT technologies." International Journal of Circuit Theory and Applications. 45.5 (2017): 2201-2210.
Lima, Catiele, José Barata, Pedro Fernandes, and Tiago Cardoso. "Urban-Architect Role in Smart-City planning - Literature Review and Case Studies." International Conference on Engineering. Madeira - Portugal 2017. Abstract

The Urban-Architect role in smart cities is a topic that has not received much attention from the scientific community. This article studies the work of the traditional responsible for thinking the cities, the Urban Architect. Under a critical proposition, aspects of this problematic are identified, which is in part nourished by the deficient action of these professionals.
The study was divided into two parts, the first one materialized through a bibliographical survey, in this section it is presented; 1 - a more detailed description of why this research work; 2 - a contextualisation of the transition of the scenarios is explained; 3 - the problematization and the reflection are raised for some reasons of the "disqualification" of the action of the architect-urbanist in the scene.
The second is based on the discussion between the authors and case studies; 4 - aspects are discussed and some characteristics are listed for "(re) framing" within the ideal scenario; 5 - four case studies are described: two smart cities built from scratch and two cities being transformed into smart cities; 6 - the limitations, conclusions and strands for future work are woven.

Boavida, Nuno, António Brandão Moniz, and Manuel Laranja The use of indicators and other evidence in two investment decisions of Technology Innovation. 21st International Conference on Science and Technology indicators. STI Conference. Peripheries, frontiers and beyond. Valencia: Editorial Universitat Politècnica de València, 2017. Abstract

Despite increasing calls for evidence-based policies, knowledge about the practical use of evidences remains limited. This paper studies the process of construction of evidences in decisions of innovation policy to understand how evidences were used. It analysis the use of indicators and other evidences through interviews conducted to inquire about the two decisions: an electric mobility policy and a nanotechnology laboratory. Results show indicators and other evidences were brought to decision processes according to their availability and capacity to support the different interests of the actors and
the stakeholders. Their role was influenced by the particular situation of the decision makers. More importantly, the use of persuasive analytical evidences appears to be related with the adversity of the policy context. In addition, research suggests that indicators are one tool among others to foster innovation decisions. In fact, the relatively minor instrumental role of indicators suggests that indicators are mostly a complementary instrument of decision. When used relevantly, indicators can offer support to a decision. But there are other significant influences that need to be taken into account to understand the specific role indicators and other evidences play, such as the social relations of the decision makers and their emotional-intuitive decisions.

Goswami, S., S. Nandy, A. N. Banerjee, A. Kiazadeh, G. R. Dillip, JV Pinto, S. W. Joo, R. Martins, and E. Fortunato. "?Electro-Typing? on a Carbon-Nanoparticles-Filled Polymeric Film using Conducting Atomic Force Microscopy." Advanced Materials. 29 (2017). Abstract
n/a