Repository logo
 

Ciências e Tecnologia | Comunicações em congressos, conferências, seminários/Communications in congresses, conferences, seminars

Permanent URI for this collection

Browse

Recent Submissions

Now showing 1 - 10 of 214
  • Considering traditional practices a study on the fishing and production of dried Sparisoma cretense in the Azores Islands
    Publication . Brás, Márcia; Fraga, Ana; Seixas, Sónia
    The practice of producing dried Sparisoma cretense (parrotfish), known locally as Veja seca, serves as a significant aspect of the maritime tradition in the Azores Islands. This study presents an interdisciplinary comprehensive analysis of the fishing and production techniques involved in Veja seca across the archipelago, while also characterizing the individuals engaged in this practice. Through structured surveys conducted on all nine islands (one hundred), this research meticulously documents the geographical distribution of Veja seca production and identifies the diverse fishing methods utilized, including shore fishing, boat fishing, and spearfishing, along with the optimal conditions for catch (bait, season, tide). Furthermore, it provides a detailed examination of the salting and drying processes, highlighting traditional methods of preservation and storage. By uncovering the sociocultural significance of Veja seca within Azorean communities this study elucidates its role in preserving local customs and sustaining cultural identity within coastal communities, which we believe to be an important contribute to be considered in local management process and fisheries management advice.
  • Enhancing recruitment with LLMs and chatbots
    Publication . Novais, Liliana; Rocio, Vitor; Morais, A. Jorge
    Traditional approaches in the competitive recruitment landscape frequently encounter difficulties in effectively identifying exceptional applicants, resulting in delays, increased expenses, and biases. This study proposes the utilisation of contemporary technologies such as Large Language Models (LLMs) and chatbots to automate the process of resume screening, thereby diminishing prejudices and enhancing communication between recruiters and candidates. Algorithms based on LLM can greatly transform the process of screening by improving both its speed and accuracy. By integrating chatbots, it becomes possible to have personalised interactions with candidates and streamline the process of scheduling interviews. This strategy accelerates the hiring process while maintaining principles of justice and ethics. Its objective is to improve algorithms and procedures to meet changing requirements and enhance the competitive advantage of talent acquisition within organisations.
  • Low temperature thermal energy storage: insights into odd-even n-alkane system
    Publication . Sequeira, Maria Carolina; Nogueira, Bernardo; Nikitin, Timur; Caetano, Fernando J. P.; Diogo, Herminio; Fausto, Rui; Fareleira, João M. N. A.
  • Revisiting odd-even effects in n-alkane systems
    Publication . Fausto, Rui; Sequeira, Maria Carolina; Caetano, Fernando J. P.; Diogo, Herminio; Fareleira, João M. N. A.; Nikitin, Timur; Fausto, Rui
    n-Alkanes have been widely studied for different applications. Recently, they became still more popular due to their exceptional characteristics as phase change materials (PCMs) for thermal energy storage (TES) applications [1]. In our research group, during the last three years, we have been studying the phase equilibrium behaviour of some binary systems with potential application as PCMs, including n-alkanes [2,3]. In this study, the n-alkanes family has shown some intriguing effects, related to the odd or even number of carbon atoms of the molecules on the characteristics of their solid-liquid phase equilibria. Several studies regarding the solid phase properties have been carried out to understand this type of phenomena in n-alkanes and compounds whose molecules contain alkyl groups. It has been established that n-alkanes exhibit different crystal packing arrangements according to their odd or even number of carbon atoms in their chains [4]. As a result, several properties are seen to be affected by the number of carbon atoms, revealing remarkable odd-even effects, which can eventually be used as an advantage for some specific applications [5]. This is particularly important to interpret and predict the solid-liquid phase equilibrium types of the diagrams, which is a key issue to select PCMs for TES applications. Most of the studies involving the properties of n-alkanes are devoted to the liquid phase. Therefore, along the years, a wide range of properties have been measured, predicted, correlated, and interpreted, including viscosity, density, heat capacity, vapour pressure, flash point, boiling point, and thermal conductivity. It is generally known that linear alkanes are an interesting homologous series, because they show a considerable regularity in their fluid phase properties, which allows to establish, for example, simple correlations based on the number of carbon atoms in the molecular chain [4]. Because of the raising importance of energy storage, namely TES, and the application of alkanes as PCMs, interest in their solid-liquid phase equilibria has increased. Consequently, it is interesting to picture an overall image on the thermophysical properties of n-alkanes, and, in particular to study the predictability of the main characteristics of their solid-liquid phase equilibria. Thus, this work aims to be a comprehensive view on the thermophysical properties and phase equilibrium behaviour of n-alkanes and their relation to the odd or even carbon atoms present in the alkyl chain.
  • Seeking new low temperature energy storage systems: n-alkanes as phase change materials
    Publication . Sequeira, Maria Carolina; Nogueira, Bernardo A.; Nikitin, Timur; Caetano, Fernando J. P.; Fareleira, João M. N. A.; Fausto , Rui; Diogo, Herminio
    Over the last decades, the increasing need for energy has been a tremendous challenge. Until now, fossil fuels have been the dominant energy source, however, due to their environmental consequences, renewable energies are the promising solution for the future.1 Nevertheless, the intermittent nature of most renewable energy sources often leads to a discrepancy between the energy produced and its consumption, which highlights the crucial role of energy storage technologies in enhancing clean energy utilization.2 From all energy storage solutions, thermal energy storage (TES) is one of the most promising options, showing substantial energy storage capacity at an acceptable cost.3 For these applications, phase change materials (PCMs) are particularly important, especially for low temperature energy storage systems. Linear alkanes (n-alkanes) have been studied as good candidates for TES applications mainly due to their singular phase transition performance, among others.4 In the present work, it has also been studied the differences due to the odd-even carbon chain number on the solid-liquid equilibrium properties that these materials can present, which is a key aspect crucial to characterize the systems for an upcoming use as PCMs. 4,5 to be used as new PCMs For TES applications, solid-liquid phase equilibrium is determinant to characterize the phase transitions which are more important for the application of these systems, as new PCMs. As an example, in the logistics associated to the transport of perishable consumables, like vaccines and other pharmaceutical products, TES plays an important role. In the present context, this work aims at the characterization of some selected n-alkane binary systems that can be used for energy storage applications at low temperatures, including the construction of the solid-liquid binary phase diagrams at sub-zero temperatures using differential scanning calorimetry (DSC), hot stage microscopy (HSM) and Raman spectroscopy. The studied systems composed by odd and even n-alkanes, have showed different solid-liquid equilibrium behaviour. The HSM and Raman spectroscopy were fundamental to obtain the binary phase diagrams, but also to visualize the changes taking place in real time as a function of temperature and often the identification of the different solid and liquid phases exhibited by these systems. This work presents some preliminary phase equilibrium data, which, to the knowledge of the authors, are not available in the literature, and are presently being prepared for publication in an international scientific journal. The presentation will also include comparisons with spread literature data, when available. All these studied systems have promising characteristics for low temperature energy storage. With this work, it is also demonstrated how solid-liquid phase equilibrium studies are a central key to select the most adequate phase change material for a specific TES application.
  • Thermophysical properties of n-alkane system for low temperature thermal energy storage
    Publication . Nogueira, Bernardo A.; Nikitin, Timur; Diogo, Hermínio P.; Fausto, Rui; Fareleira, João; Caetano, Fernando J. P.; Sequeira, Maria Carolina
    Over the past few decades, the escalating need for energy has posed a significant and pressing challenge. For centuries, fossil fuels stood as the dominant energy source; however, due to their dwindling availability and environmental complications, renewable energies have emerged as the promising solution for the future [1]. The intermittent nature of renewable energy sources often results in a disconnect between energy production and consumption, underscoring the vital role of energy storage technologies in enhancing clean energy utilization [2]. Among various energy storage solutions, thermal energy storage (TES) shines as one of the most promising options, offering substantial energy storage capacity at a relatively low cost [3]. In this context, phase change materials (PCMs) are particularly crucial, namelyfor active cooling systems. N-alkanes have been widely investigated for TES applications due to their singular characteristics including their phase transition performance, among others [4]. The objective of this work is to characterize selected n-alkane systems, involving the construction of the solid-liquid binary phase diagrams, using differential scanning calorimetry (DSC) and Raman Spectroscopy. Additionally, the present research efforts seek to obtain the thermal conductivity of these systems. The ongoing investigations play a critical role towards understanding the properties of these systems, enabling to predict their thermal characteristics and performance as PCMs for TES applications. Particularly, for new PCMs phase equilibrium studies are essential to select the appropriate systems with the desired properties for each application. This work is focused on binary systems composed by odd and even alkanes, in particular the binary mixtures C8–C10, C9–C10, C9–C11 and C10–C12. These systems revealed different solid-liquid phase equilibrium behaviour at low temperatures, although three of these four systems exhibited promising capabilities to be used for TES applications at low temperatures. Detailed results on these binary systems will be presented and discussed.
  • A systematic literature review on the learning technologies implemented in organizations
    Publication . Ferreira, Helena; Santos, Arnaldo
    The performance and survival challenges faced by many organizations require dynamic capabilities and tools to accelerate the acquisition of those capabilities. Organizations are continuously looking at their learning strategies as a key factor to prepare their human capital for the rapid changes and demands. Learning Technologies are positioned as an enabler that provides different opportunities to learn and that is why they are so important. The design of strategies for the implementation of learning technologies in organizations is hard to be overviewed. Only a few contributions address technology as a crucial point to accelerating performance, innovation, and competitiveness. In this research, we will focus on the strategic implementation of learning technologies. The approach we chose to solve this problem is to develop guidelines that support the strategy for the implementation of technology in the learning field. This approach will allow us to relate the strategy with the challenges faced and the impact that the organization is expected to achieve.
  • UAbALL - Automata Learning Lab
    Publication . Oliveira, Rúdi Gualter de; Sousa, André Maciel da Silva e; Pinto, Mara; Viana, Nuno Almendra e; Morais, A. Jorge
    E-learning has been important in higher education, enabling people to continue their education with more flexibility. Virtual laboratories play a crucial role in Computer Science distance learning degrees, by enabling students to study at their rhythm and getting practical answers to practical problems immediately. Theoretical models such as finite automata, pushdown automata, context-free grammars, Turing machines, etc., are essential for understanding the grounds of languages and computability and are also the basis for the implementation of compilers. In this paper, a new virtual laboratory is presented, UAbALL - Automata Learning Lab, developed at Universidade Aberta (UAb), the Portuguese Open University. This virtual laboratory has already been tested in the curricular unit of Languages and Computation, with good feedback from the students. A comparison to other tools was performed showing that UAbALL is more complete in terms of tools provided.
  • Chatbots scenarios for education
    Publication . Virkus, Sirje; São Mamede, Henrique; Rocio, Vitor; Dickel, Jochen; Zubikova, Olga; Butkiene, Rita; Vaiciukynas, Evaldas; Ceponiene, Lina; Gudoniene, Daina
    Educational chatbots are digital tools designed to assist learners in various educational settings. These chatbots use natural language processing (NLP) and machine learning algorithms to simulate human conversation and respond to user queries in a way that facilitates learning. They can be integrated into various educational platforms such as learning management systems, educational apps, and websites to provide learners with a personalized and interactive learning experience. Our paper discusses different scenarios for educational purposes and suggests in total four scenarios for educational needs.