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- Tailor-made SCC incorporating spent equilibrium catalyst from oil refineryPublication . Nunes, Sandra; Costa, CarlaThe spent equilibrium catalyst (ECat) is a waste generated by the oil-refinery industry with very high pozzolanic activity and, therefore, has a great potential as an addition in SCC. This paper describes research on the use of factorial Design of Experiments (DoE) approach to design SCC mortar mixtures incorporating ECat. As such, a central composite design was carried out to mathematically model the influence of mixture parameters and their coupled effects on deformability, viscosity, compressive strength, resistivity and ultrasonic pulse velocity. Thereafter, a numerical optimization technique was applied to the derived models to select the best mixture, which simultaneously maximizes different engineering properties and eco-efficiency, while maintaining self-compactability.
- Multi-level study on UHPFRC incorporating ECatPublication . Abrishambaf, Amin; Pimentel, Mário; Nunes, Sandra; Costa, CarlaThe suitability of a recently developed ultra-high performance fibre reinforced cementitious composite (UHPFRC) incorporating Spent Equilibrium Catalyst, ECat, for structural applications is investigated through a systematic multi-level investigation across micro, meso and composite levels. Scanning electron microscopy, isothermal calorimetry, thermogravimetric analysis, and mercury intrusion porosimetry tests were performed to evaluate the microstructure of the composite. At the meso-level, the mechanical properties of fibre to matrix ITZ were characterised by single fibre pullout tests on fibres embedded with various fibre orientation angles. At the composite level, specimens with 3% fibre content and different fibre orientation profiles were prepared to determine uniaxial tensile behaviour. The relation between the tensile fracture parameters and fibre structure parameter was assessed. In each level, the results are compared to a conventional ternary UHPFRC mixture and point towards the suitability of the newly developed mixture for structural applications.
- Spent equilibrium catalyst as internal curing agent in UHPFRCPublication . Matos, Ana Mafalda; Nunes, Sandra; Costa, Carla; Aguiar, J. B.The main goal of the current paper is to optimize ultra-high performance cementitious material (UHPC) mixes incorporating the spent equilibrium catalyst (ECat) to mitigate autogenous shrinkage. Design of experiments approach was used to optimize mixtures targeting different engineering properties, namely, self-compactibility, low early-age shrinkage and cracking risk, improved durability and high mechanical performance. The statistical models established indicated that ECat exhibits a strong positive effect on the autogenous shrinkage mitigation of UHPC attributed to the water absorbed in the porous of ECat particles. The proposed optimal UHPC mixture represents the best compromise between low autogenous shrinkage - 32% of reduction - and high resistivity at 28 days without impairing self-compatibility and compressive strength. This optimal UHPC combined with 3% high-strength steel fibres (l(f)/d(f) = 65) proved to be comparable to other Ultra High-Performance Fibre Reinforced Composites (UHPFRC), in terms of mechanical behaviour, and more eco-friendly and cost-efficient than UHPCs reported in the literature.
- Durability of an UHPC containing spent equilibrium catalystPublication . Matos, Ana Mafalda; Nunes, Sandra; Costa, Carla; Aguiar, JoséUHPC is an advanced cementitious material able to meet the current construction industry challenges regarding structural safety and durability. However, new UHPC formulations with limited shrinkage are still being pursued to reduce residual tensile stresses in the UHPFRC layers, for rehabilitation/strengthening applications. This investigation estimates the durability of a non-proprietary UHPC incorporating a by-product originated by the oil refinery industry (ECat), as an internal curing agent. Direct and indirect transport properties measurements as well as the carbonation assessment and evaluation of dimensional resilience to potential deleterious reactions revealed that the new UHPC possesses an excellent durability performance, typical of these materials. These results combined with its self-compacting ability, low autogenous shrinkage and high compressive strength confirm the belief in the role of this new UHPC towards a high-tech construction.
- Optimisation of hydraulic lime mortars incorporating an oil-refinery catalyst by-product for sustainable building rehabilitationPublication . Costa, Carla; Nunes, SandraAbstract This investigation employs a Central Composite Design-based Design of Experiments (DoE) methodology to develop hydraulic lime mortars incorporating equilibrium catalyst (ECat), a by-product generated at the fluid catalytic cracking unit in oil refineries. The derived mathematical models describe the quantitative effects of key mixing variables, specifically ECat content, water-to-binder ratio and water repellent dosage, as well as their cross-interactions, on mortar properties, namely workability, compressive strength, ultrasound propagation velocity and dynamic modulus of elasticity. Numerical optimisation techniques enabled the identification of optimal lime mortar compositions that maximise eco-efficiency while ensuring compliance with both regulatory and technological requirements for diverse masonry applications, including the rehabilitation of ancient buildings. Results confirm the by-product upcyclability of ECat, with feasible incorporation levels up to 56.6 % by mass, yielding mortars with significant potential for reducing the environmental impact of the built environment while advancing the circular economy and fostering technological innovation in the construction sector.
- Sustainability, technology and co-creation: a virtuous circle for sustainable tourism in Lisbon regionPublication . Costa, Teresa; Machado, Ana Teresa; Nunes, Sandra; Santos, Zelia Raposo; Severino, Filipe Segurado; Cristina, Margarida; Roque, Ana GláuciaThis study examines the interrelationship between sustainability values, technology, and co-creation in tourism. While prior research has underscored the significance of sustainability in influencing tourist behaviour, this study reveals that sustainability values do not directly affect co-creation intentions. Instead, technology emerges as a pivotal mediating factor, bridging the gap between sustainability awareness and active participation in co-creation. Employing a sample of 401 tourists in Lisbon, the study utilises Partial Least Squares (PLS) structural equation modelling to analyse the relationships among these variables. The findings indicate that tourists with strong sustainability values perceive technology as an essential facilitator of responsible tourism. However, sustainability values alone do not significantly influence tourists’ perception of co-creation value or their intention to engage in co-creation activities. These results suggest that although sustainability-conscious tourists may endorse eco-friendly tourism, they do not necessarily engage in participatory co-creation behaviours unless technology is incorporated into the process. This finding implies that sustainability is frequently regarded as a passive commitment rather than an interactive, co-created experience. From a practical perspective, the study offers valuable insights for tourism stakeholders seeking to develop technology-driven solutions that enhance sustainable and interactive travel experiences. The findings suggest that digital platforms, artificial intelligence-powered tools, and blockchain-based transparency mechanisms can facilitate co-creation while fostering responsible tourism practices. By integrating sustainability and technological perspectives, this study contributes to theoretical advancements and provides strategic recommendations for promoting meaningful and sustainable tourism experiences in the digital era.
- Gestão da imagem de destino: a perceção e os fatores de atração da Área Metropolitana de Lisboa entre estudantes universitáriosPublication . Severino, Filipe Segurado; Costa, Teresa; Cristina, Margarida; Roque, Ana Gláucia; Nunes, Sandra; Santos, Zelia RaposoEste estudo explora as perceções de estudantes universitários, tanto residentes portugueses como estudantes internacionais a viver em Lisboa, relativamente às principais atrações da Área Metropolitana de Lisboa, em Portugal. Estes estudantes, ao residirem atualmente em Lisboa, representam também potenciais turistas futuros. Compreender as suas perspetivas sobre as atrações de Lisboa visa fornecer contributos que possam orientar estratégias de destinos noutras regiões. Recorrendo a uma abordagem de métodos mistos, a investigação analisa as características específicas que atraem estes estudantes para Lisboa, cidade reconhecida pelo seu rico património cultural e ambiente vibrante. Os dados foram recolhidos junto de estudantes de duas instituições de ensino superior, através de questionários interativos com conteúdos multimédia sobre a área. O estudo destaca que os marcos culturais e históricos, as condições climáticas favoráveis e o compromisso com a sustentabilidade ecológica são elementos-chave que contribuem para a atratividade. Os resultados demonstram que estas características não só atraem potenciais turistas futuros, como também permitem aos destinos potenciar os seus atributos únicos para aumentar a atratividade e enfrentar os desafios da sustentabilidade. Esta análise aprofunda a compreensão das perceções dos turistas e das qualidades dos destinos, oferecendo contributos relevantes para iniciativas de gestão e marketing de destinos orientadas para práticas de turismo sustentável.
- SHIFT & Inspire: tourism & hospitality trendsPublication . Costa, Teresa; Calisto, Maria de Lurdes; Machado, Ana Teresa; Ramos, Célia Quitéria; Montargil, Filipe; Severino, Filipe Segurado; Ferreira do Rosário, João Carlos Vinagre; Umbelino, Jorge; Belo, Miguel; Madeira, Rui Neves; Nunes, Sandra; Santos, Zelia RaposoWelcome to “Shift & Inspire: Tourism and Hospitality Trends”, an e-book that explores the dynamic and ever-changing landscape of tourism and hospitality in a world undergoing profound transformation. As we embark on this journey, we delve into the diverse forces that shape the industry, touching upon crucial themes that are shaping the present and moulding the future.
- The macro context for entrepreneurship in tourism: a review of emerging trendPublication . Costa, Maria Teresa; Calisto, Maria de Lurdes; Machado, Ana Teresa; Santos, Zelia Raposo; Nunes, Sandra; Severino, Filipe SeguradoAbstract: Tourism has an enormous economic and employment potential, which, at least until 2019, encouraged many countries to develop their tourism offer and attract more tourists. Then the COVID-19 pandemic happened, and nowadays, Europe, the most important tourism destination in the world, faces a new war and refugee crisis. Tourism is an activity that propels the economy and job creation internationally; nevertheless, the activity is vulnerable to macro environment events. Both aspects are crucial issues for tourism entrepreneurs. Therefore, it is relevant to understand the emerging trends that entrepreneurs may face. Based on a systematic literature review, this paper aims to identify the major macro-environmentalfactors that impact tourism activity by answering the following research question: What contextual factors should entrepreneurs expect to impact their businesses? A systematic literature review was conducted in three steps: 1) selection of the relevant sources (on WoS and Scopus-indexed journals) using appropriate selection criteria that fitted the research questions; 2) assessment of the selected articles according to exclusion criteria to reach a final sample of articles; 3) full analysis of the base of final articles to identify emerging trends associated to relevant contextual factors. Results suggest that political-legal, technological, sociocultural, and sustainability-related factors have been the most relevant ones. This study has relevant contributions to practice since it highlights what entrepreneurs should expect from the macro environment. It also contributes to tourism literature by opening new lines of research and synthesising the trends impacting tourism activity.
- An importance–performance analysis approach to a tourism destination: the case of Lisbon metropolitan area, PortugalPublication . Costa, Maria Teresa; Calisto, Maria de Lurdes; Santos, Zelia Raposo; Severino, Filipe Segurado; Nunes, Sandra; Rosário, João Ferreira doAbstract: Pull factors, the attributes of a specific location, matter in tourism. These factors encompass the distinctive characteristics and alluring features that attract tourists to a destination, their importance and performance influencing the decision-making process and overall experience. A clear comprehension of this concept is crucial for destinations' economic vitality as they compete for tourists and strive for economic expansion and employment prospects. Indeed, an in-depth knowledge of these factors' importance and performance underscores the need for regions to adjust their approach to evolving tourist preferences. This adaptation is crucial to fostering responsible and sustainable tourism practices that safeguard cultural and natural resources. However, besides learning about the factors considered critical by tourists to visit a location, it is paramount to analyse how they evaluate the performance of each of these factors while staying there.This study focuses on the Lisbon Metropolitan Area (LMA), Portugal, and the findings will provide essential insights into destination competitiveness, sustainable tourism development, and the creation of unique travel experiences. As a destination that gained popularity, attracting tourists from all over the world, it is necessary to comprehend the specific factors that contribute to this vibrant region's allure and how it performs regarding them. The research will use the Importance-Performance Analysis to make data interpretation accessible and suggest relevant measures to improve competitiveness based on optimising the allocation of resources among the various factors/attributes analysed. The research incorporates numerous criteria categories, including historical significance, urban appeal, natural scenery, culinary experiences, cultural heritage, and aspects like streets' cleanliness, transport availability, or health emergency infrastructures.The study's conclusions will impact Lisbon region's (LMA) tourism and destination management. By understanding what factors are more important for tourists that visit the area and their evaluation of the performance of each of these factors,stakeholders can improve marketing, infrastructure, and the visitors' experience to promote sustainable development and maintain Lisbon's standing as a top tourist destination for rewarding and enlightening experiences. Relevant data is also provided to inform future tourism initiatives. This study adds to the academic discussion of location competitiveness and unique travel experiences.