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- Direct Load Control in the Perspective of an Electricity Retailer – A Multi-Objective Evolutionary ApproachPublication . Gomes, Álvaro; Antunes, Carlos Henggeler; Oliveira, EuniceThe judicious use of end-use electric loads in the framework of demand-side management programs as valuable resources to increase the global efficiency of power systems as far as economical, technical and quality of service aspects are concerned, is a relevant issue in face of the changes underway in the power systems industry. This paper presents the results of a multi-objective optimization model, in the perspective of an electricity retailer, which is aimed at designing load control actions to be applied to groups of electric loads. An evolutionary algorithm is used to compute solutions to this problem.
- Gyrogroups in Projective Hyperbolic Clifford AnalysisPublication . Ferreira, MiltonUsing the projective hyperbolic model in Clifford analysis we show that different velocities in special relativity theory (non-standard velocities, coordinate velocities and proper velocities) corresponds to taking different realizations of the hyperbolic geometry in the projective model. A full description of the changes is given, together with a proof of the isomorphism of the related gyrogroup structures (Möbius, Einstein, and proper velocity gyrogroups).
- 3D Video Representation and CodingPublication . Faria, Sergio M.M.; Debono, Carl J.; Nunes, Paulo; M. M. Rodrigues, NunoThe technologies which allow an immersive user experience in 3D environments are rapidly evolving and new services have emerged in various fields of application. Most of these services require the use of 3D video, combined with appropriate display systems. As a consequence, research and development in 3D video continues attracting sustained interest. While stereoscopic viewing is already widely spread, namely in TV and gaming, new displays and applications, such as FTV (Free viewpoint TV), require the use of a larger number of views. Hence, the multiview video format was considered, which uses N views, corresponding to the images captured by N cameras (either real or virtual), with a controlled spatial arrangement. In order to avoid a linear escalation of the bitrate, associated with the use of multiple views, video-plus-depth formats have been proposed. A small number of texture and depth video sequences are used to synthesize intermediate texture views at a different space position, through a depth-image-based rendering (DIBR) technique. This technology allows the use of advanced stereoscopic display processing and to improve support for high-quality autostereoscopic multiview displays. In order to provide a true 3D content and fatigue-free 3D visualization, holoscopic imaging has been introduced as an acquisition and display solution. However, efficient coding schemes for this particular type of content are needed to enable proper storage and delivery of the large amount of data involved in these systems, which is also addressed in this chapter.
- Structural Shear Stress Evaluation of Triple Periodic Minimal SurfacesPublication . Almeida, H.A.; Bártolo, P. J.Tissue engineering represents a new, emerging interdisciplinary field involving combined efforts of several scientific domains towards the development of biological substitutes to restore, maintain, or improve tissue functions. Scaffolds provide a temporary mechanical and vascular support for tissue regeneration while shaping the in-growth tissues. These scaffolds must be biocompatible, biodegradable, with appropriate porosity, pore structure and pore distribution and optimal structural and vascular performance, having both surface and structural compatibility. Surface compatibility means a chemical, biological and physical suitability to the host tissue. Structural compatibility corresponds to an optimal adaptation to the mechanical behaviour of the host tissue. The design of optimised scaffolds based on the fundamental knowledge of its macro microstructure is a relevant topic of research. This research proposes the use of geometric structures based on Triple Periodic Minimal Surfaces for Shear Stress applications. Geometries based on these surfaces enables the design of vary high surface-to-volume ratio structures with high porosity and mechanical/vascular properties. Previous work has demonstrated the potential of Schwartz and Schoen surfaces in tensile/compressive solicitations, when compared to regular geometric based scaffolds. The main objective is to evaluate the same scaffold designs under shear stress solicitations varying the thickness and radius of the scaffold’s geometric definition.
- Electrospinning for Medical ApplicationsPublication . Song, Wenhui; Mitchell, Geoffrey R.; Burugapalli, KrishnaThere is a natural connection between a variety of electrospun fibres and biomedical applications. The most commonly quoted application of electrospun fibres is their use as scaffolds in tissue engineering for regenerative medicine. There are also many other applications, which include drug delivery systems, membrane systems and analytical functionality. This chapter identifies the key challenges in each of these topics, as well as the particular role of electrospun fibres in addressing these challenges.
- Permeability Evaluation of Flow Behaviors Within Perfusion BioreactorsPublication . Freitas, D.; Almeida, H.A.; Bártolo, P. J.Tissue engineering aims to produce artificial tissue in order to create or repair damaged tissue. It is evident that scaffolds are of extreme importance, because they will be the support structure of the new tissue. This new tissue is cultivated in vitro in a bioreactor in which is placed the scaffold. In order to control the cell culture process inside of a bioreactor, it is essential to know the fluid flow inside the scaffold for an adequate exchange of nutrients and metabolic waste. A novel multifunctional bioreactor with a perfusion system module comprised of three different inlet and outlet membranes is being developed. This research work will evaluate the permeability of the scaffold under the three different inlet and outlet diffusion membranes of the culture chamber.
- Characterization of the Dagorda Claystone in Leiria, Portugal, Based on Laboratory TestsPublication . Veiga, A.; Quinta-Ferreira, M.The Hetangian Dagorda claystone Formation occupies the core of a diapir outcropping in part of the city of Leiria, exhibiting a complex geological structure. The geological and geotechnical characterization is presented based in field observation and laboratory tests allowing to conclude that the Dagorda clay soils exhibit an unfavourable behaviour for urban occupation, due to the presence of expansive clay minerals. When partially saturated these soils can lead to cracking of walls and floors, or even to endanger the stability of buildings, if they have not been strengthened to resist to expansive soil. The presence of soluble minerals, mainly gypsum and seldom halite, can allow the formation of voids and eventually the deformation or collapse of the ground. Suitable safety procedures, in order to prevent hazards should be used.
- The Impact of Artificial Intelligence on Accounting—The View of Certified AccountantsPublication . Grácio, Leonor; Eugénio, Teresa; Azevedo, GraçaIn recent years, artificial intelligence (AI) has taken on an important role in various daily tasks. This is a transformative technology that is impacting several areas, one of which is accounting. The daily tasks of Certified Accountants (CAs) are increasingly being automated using machines. This scenario is evolving and transforming before the eyes of accounting professionals, which requires a high level of adaptability, as well as the new skills needed to perform the profession. The research conducted consists of a quantitative study and its general objective is to analyze the opinion of CAs on the impact that AI may have on their profession. The quantitative analysis of this work is supported by a survey addressed to CAs, which was subsequently analyzed using SPSS software. The main conclusions of this study are that CAs predict that AI will have an impact on accounting and expect the impact of this technology to be significant, but they do not agree that it will replace the profession of CA. There is also willingness on the part of the CAs for there to be collaboration between accounting professionals and AI in the future. This collaboration will bring together accounting professionals and AI, which will make it possible to get the best out of each other.
- Application of Renewable Energy—The Case of San Tomé IslandPublication . Ceita, Ludcelma de; Manso, Ricardo; Eugénio, TeresaIn the current context, the energy sector is one of the most important strategic points for the economic transformation of any society. Access to energy is a universal human right and a concern of the state. Whatever national development strategy is defined or implemented, it will always require measures to promote access to energy for all. Although the strong growth of renewable energies worldwide is evident, there are still few studies on their applicability in developing countries. The aim of this study is to contribute to energy sustainability in an emerging country where renewable energies have been little analysed and developed. The country analysed is São Tomé and Príncipe (STP). This paper develops a study on the application of renewable energy, energy sustainability, and clean electricity generation as challenges of the present and ways forward. Aware of the potential of natural resources on the islands of São Tomé and Príncipe, the study follows the following methodology: first phase: a preliminary study to describe the current energy situation on the island; second phase: presentation of a simulation on the use of available resources that has a direct impact on minimising the consumption of fossil fuels on the islands and on the country’s dependence on foreign fuel imports. As a result, the following proposal is made: Utilisation of photovoltaic solar energy with the help of agro-voltaic systems and floating panels, a biomass plant and a transition to electromobility with the help of electric vehicles as energy storage and means of transport.
- Circular Economy and Sustainability: What Are They Saying About It? – A Literature ReviewPublication . Costa, Berta; Rodrigues, SusanaCircular economy (CE) and sustainability are two interrelated con- cepts that are increasingly gaining attention in the fields of business, economics, and environmental studies. Although both concepts share similarities as they both aim to reduce the negative impact of human activities on the environment and promote sustainable development, they have predominantly been addressed sep- arately as two independent areas of knowledge, and continue to be ambiguous. Their relationship in literature has not been clarified, which may be obfuscating their overall usage. The aim of this article is to clarify the concepts of circular economy and sustainability, to examine how these two constructs have evolved in the last decades, and to identify their similarities and differences. In this regard a specific literature review was performed. For this purpose, 48 publications were identified, and a content analysis was conducted. Based on the aforementioned literature review, key findings relatively to circular economy and sustainability are presented.