ESTiG - Artigos em Revistas Indexados à WoS/Scopus
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Percorrer ESTiG - Artigos em Revistas Indexados à WoS/Scopus por Objetivos de Desenvolvimento Sustentável (ODS) "12:Produção e Consumo Sustentáveis"
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- 3D Numerical modeling of geosynthetics for soil reinforcement: a bibliometric analysis and literature reviewPublication . Paiva, Lucas; Pinho-Lopes, Margarida; Paula, António Miguel; Valente, RoberttSoil reinforcement using geosynthetics is an efficient and cost-effective solution for a variety of geotechnical structures. Along with the increasing use of geosynthetics, there is a need to expand and enhance the design methodologies for these elements, which are still frequently based on conservative limit equilibrium approaches. In this paper, a bibliometric analysis was conducted on geosynthetic-reinforced soil structures (GRS), identifying the state of the art, research trends, and other indicators. The data were obtained from the Scopus platform and processed by VOSViewer v1.6 software. The initial search comprised 552 papers and the screening process selected 516 relevant papers from 1992 to October 2023. The study analyzed the occurrence of publications by year, keyword trends, authors, citations/co-citations, and bibliographic coupling. Then, a focus was given to 3D modeling research on geosynthetics, highlighting the dominant modeling techniques, material properties, and design challenges in GRS. The bibliometric analysis provided a crucial guideline in the identification of relevant papers and research trends, and a series of conclusions were presented regarding the 3D modeling techniques, choice of material properties, and boundary conditions.
- Building resilient tourism systems: the strategic role of financial sustainability in portuguese tourism firmsPublication . Fernandes, António B. ; Ferreira, Jessica; Seidi, Fadiba; Cardim, SofiaThis study examines the economic and financial sustainability of Portuguese tourism firms operating within Division 55 (Accommodation) and Division 56 (Food and Beverage Service Activities), using Return on Assets (ROA) as the central indicator of economic and financial sustainability to assess variations over time, across firm sizes and among regions. Drawing on a dataset of 8,735 firms and 113,559 observations from 2011 to 2023, the analysis relies on ROA due to its analytical robustness and suitability for longitudinal and cross-sectional comparison. Given the absence of normality and homogeneity of variances, robust statistical techniques were applied, namely Welch’s ANOVA and the Games-Howell post hoc test with bootstrapping, to ensure reliable inference. The findings reveal significant differences in financial sustainability over the study period, between firms of different sizes and across regions. Small firms record higher average ROA than micro, medium or large firms, while the Algarve emerges as the highest-performing region and the Autonomous Region of the Azores presents the weakest results. The study is limited by its exclusive reliance on quantitative financial indicators, without incorporating qualitative dimensions that might enrich understanding of sustainability drivers, and by the constraints posed by data non-normality. The results emphasise the need for policy measures tailored to regional characteristics and highlight the pivotal role of small firms in resilience in the tourism sector. The study adds value by providing a rigorous, longitudinal and regionally differentiated analysis of financial sustainability within the Portuguese tourism industry.
- A CFD investigation of the performance of stirred tanksPublication . Youcef, Kamla; Driss, Zied; Foukrach, Mohamed; Rosa, Sérgio; Baki, TouhamiRushton turbine was employed in this study to numerically analyze the fluid flow it generates within a stirred tank. The topology of the resulting flow was found to be strongly dependent on several parameters, including the geometric configurations of the system and the properties of the moving fluids. The governing equations, based on the k-epsilon model, were solved using the finite volume method. Velocity field profiles, streamlines and vortex sizes were ana-lyzed for several geometries, varying the number of blades from 6 to 12 and others. A comparison was also conducted to evaluate the effect of the number of stirring mobiles used to mix the fluid (single stage, two stages and three stages), as well as the influence of the spacing ratio between the different stir-rers. Finally, our numerical simulation procedure was validated through com-paring the results obtained with experimental work available in the literature, showing good agreement between the different approaches.
- Comparação de métodos de dimensionamento geotécnico e estrutural de microestacas: análise por meio de estudo paramétricoPublication . Souza, Lucas de Freitas; Braz-César, Manuel; Pereira, Armando Belato; Paula, António MiguelEste artigo apresenta uma análise crítica de diferentes métodos de dimensionamento geotécnico e estrutural aplicáveis a microestacas. Foram avaliados métodos clássicos e contemporâneos, considerando-se variáveis geométricas como o diâmetro de perfuração, comprimento da raiz e propriedades da armadura tubular. A metodologia incluiu um estudo de caso real, baseado em dados de campo e parâmetros obtidos por sondagem dinâmica, complementado por análises paramétricas implementadas em ambiente computacional. Os resultados permitiram quantificar a sensibilidade de cada método às alterações geométricas, destacando as divergências entre critérios de capacidade de carga do solo e de estabilidade estrutural. Verificou-se que alguns métodos apresentam variações significativas nos resultados. A abordagem adotada proporciona uma base técnica mais sólida para a comparação entre diferentes modelos de dimensionamento de fundações profundas, contribuindo para escolhas mais fundamentadas em projetos de fundações em ambientes urbanos ou industriais.
- Do green innovation strategies exist? Past, present and future trends in literaturePublication . Silvério, Ana Cristina; Fernandes, Cristina I.; Maran, Thomas K.For companies to subsist in the highly changeable and competitive market, they must foster innovation. Similarly, for companies to respond to market changes, fluctuations and trends, they need to develop green-oriented strategies. Therefore, reversing the innovation process to be greener is becoming a strategic opportunity for companies. As well as contributing to the company's long-term performance, green innovations can be a differentiation tool for improving the company's competitive position. Despite the growth in literature on green innovation strategies, the field is dispersed. This paper therefore provides a comprehensive overview of past, present and future trends in the literature on green innovation strategies through a systematic literature review and a bibliometric analysis, employing two bibliometric techniques: bibliographic coupling and cluster analysis.FindingsFor this purpose, the Web of Science database was used, where 509 documents were collected, which were then subjected to a selection process. In total, 63 scientific studies were selected and analyzed, resulting in the identification and classification of theoretical perspectives on green innovation strategies, in which five main approaches emerged: (1) Implications of green innovation strategies, (2) Drivers of green innovation strategies, (3) Diffusion/diffusers of green innovation strategy, (4) Internal and external drivers of green innovation strategy and (5) Stakeholders in the green innovation process. The review highlighted existing gaps in the literature and illuminated avenues for future research, indicating potential research questions. Originality/valueCollectively, our findings hold significant implications for organizational strategies by providing a robust framework for firms to understand critical factors influencing green innovation. Beyond its strategic relevance, this study advances the green innovation management literature through a holistic framework analyzing how companies can strategically pursue green innovation driven by internal and external factors.
- Experimental investigation of cellular steel beams at ambient and elevated temperaturesPublication . Silva, Luana Vidoti da; Giacomitti, Nickolas; Ferreira, Débora; Lopes, Nuno; Mesquita, Luís M.R.Cellular steel beams, commonly used in modern construction, exhibit complex failure mechanisms that have not been thoroughly explored, especially under fire conditions. This research investigates the structural behaviour of cellular beams under both ambient and elevated temperatures, with a focus on load-bearing capacity and failure modes. Experimental tests were conducted on a solid beam and six cellular beams with varying hole spacings and diameters at different temperatures. All beams were tested under three-point bending, subjecting the openings and the web posts to different combinations of bending moments and shear forces. Experimental maximum loads and failure modes are compared with the design method of EN1993-1-13 and EN1993-1-2. At ambient temperature, failure modes varied with beam design: specimens with smaller opening spacings failed by web-post buckling, while larger openings resulted in a Vierendeel mechanism. While the Eurocode predictions for load capacity were conservative under ambient conditions, the design model did not accurately predict the correct failure mode. Elevated temperatures significantly reduced the load capacity and, in some cases, changed the collapse mechanism. These results highlight that current design rules are unreliable in predicting the failure mode and may not ensure safety at higher temperatures, stressing the need for specific design rules for cellular beams in fire conditions.
- Fire resistance of protected glued laminated timber columns: geometry, load and cladding effectPublication . Piloto, Paulo A.G.; Lorenzo, Manuel D.; Ramos-Gavilán, Ana B.; Sánchez-Haro, Javier; Lannou, Loïc; Bouchaïr, AbdelhamidTimber, as a sustainable and renewable building material, is becoming increasingly popular in modern architecture due to its aesthetic appeal, low environmental footprint, and structural ability. Glued-laminated timber (GLT) is commonly used for columns and beams in mid to high-rise buildings due to its strength and spanning ability. However, concerns about timber's combustibility raise safety concerns that demand the use of effective fire protection materials. One such method is the application of gypsum cladding, which provides thermal insulation and delays heat transfer to the timber, thus enhancing fire resistance. This study investigates the fire resistance of gypsum-protected GLT columns, focusing on the effects of geometry, load level, and cladding configuration. The European Charring Model (ECM) and the effective cross-section design method are used alongside with three experimental tests, full three-dimensional computational model and a parametric study. The results provide valuable insights into the thermal insulation performance of gypsum cladding, the charring behaviour of timber under fire, and the influence of different protection layers and load levels on overall fire performance. Under 36 % load level, doubling the protection layer, increases the fire resistance up to 95 %. Changing the material grade from GL24h to GL28h, increases the fire resistance, from 2 % to 12 %, depending on the slenderness of the column, while increasing the load level from 6 % to 36 % reduces the fire resistance up to 47 %. This research contributes to fire safety and supports the expanded use of engineered timber in sustainable building designs by improving knowledge of its fire performance characteristics.
- Fostering success of collaborative research, development, and innovation projects through project management officesPublication . Santos, José M.R.C.A.; Fernandes, Gabriela; Ribeiro, Pedro; Ferreira, Luís Miguel D.F.; Barroso, Daniela; Pinto, Eduardo B.Publicly funded collaborative research, development, and innovation (CRDI) projects are increasingly promoted to tackle key societal challenges. However, the success of these projects is difficult to appraise, and the role of project management offices (PMOs) to potentiate the project success is not well understood. This study contributes to the debate about the effectiveness of projects in research and innovation by elucidating the relationship between the existence of a PMO and the success of CRDI projects, and the role that project management practices play in this regard. Using the lens of Ika and Pinto’s project success theoretical framework it was found that PMOs contribute to the success of CRDI projects by facilitating the use of relevant project management practices. From a practical point of view, organizations involved in CRDI projects can gain insights into how a PMO can foster project benefits, stakeholder alignment and knowledge management.
- FSC Certification in the Sustainability Management Control Systems: A Case Study of Four Wood Trading CompaniesPublication . Leite, Joaquim; Ribeiro, Vânia; Carmo, CecíliaThere are many management indicators on sustainability, but it is important to better understand the practices and the underlying reasons for including the monitoring of forestry certificates in management control. The purpose of this paper is to examine how and why Forest Stewardship Council (FSC) certification is incorporated into sustainability management control systems (MCSs). FSC certification serves as a credible tool for companies to demonstrate their alignment with the Sustainable Development Goals (SDGs), enhancing stakeholder confidence. The literature review centers on the concepts of FSC certification and sustainability MCSs. A multiple case study methodology was employed, focusing on four companies in the wood and wood-based product sector, particularly those with forestry certifications like FSC. Data were collected from documents published online by the companies studied, followed by a content analysis typical of qualitative research. The results show that the companies studied integrate FSC certification into their MCSs through diverse practices (how?) driven by sustainability motivations (why?). These firms adopt and promote sustainable initiatives, embedding FSC principles into their systems for performance monitoring and assessment. The findings indicate that companies in this sector not only adopt sustainable practices but also prioritize sharing information about these efforts. Practically, it was observed that retail businesses dealing with wood and wood-based products incorporate seven out of the ten FSC principles into their management systems. This reflects a significant level of integration of FSC certification within the MCSs of the analyzed companies.
- Impact of hyper-parameter tuning on CNN accuracy in agricultural image classificationPublication . Mendes, João; Lima, José; Costa, Lino; Hendrix, Eligius M.T.; Pereira, Ana I.This study explores the impact of hyper-parameter optimization on the performance of convolutional neural networks (CNNs) for olive cultivar classification using transfer learning. Pre-trained ImageNet models such as VGG16, InceptionV3, and ResNet50 were adapted to a proprietary dataset, with VGG16 selected for detailed evaluation. Key hyper-parameters, including layer count, neurons per layer, dropout rate, learning rate, and batch size, were tuned using random search. The best configuration achieved a validation accuracy of 87.5%, significantly outperforming the control model. Sensitivity analyses with Morris and Sobol methods identified the number of layers as the most influential factor, followed by dropout and learning rates through interaction effects. These findings demonstrate the importance of tailoring CNN architecture and regularization settings to the problem domain. These results underscore the importance of tuning architectural depth and regularization mechanisms for performance optimization. As a practical guideline, models with fewer layers and intermediate dropout levels demonstrated higher robustness and generalization, offering an effective strategy for adapting CNNs to agricultural classification tasks.