https://hdl.handle.net/10216/152 Fri, 24 Jul 2026 01:51:57 GMT 2026-07-24T01:51:57Z https://hdl.handle.net/10216/175336 Title: Enhancing the mechanical performance of mixed recycled aggregates for unbound pavement layers Abstract: The use of recycled aggregates in road pavements can markedly contribute to more sustainable infrastructures, minimising the extraction of virgin aggregates and using secondary materials that would otherwise be discharged into the environment with negative impacts. In Portugal, as in most Southern European countries, most of the recycled aggregates coming from construction and demolition waste are mixed or non-selected recycled aggregates, containing concrete and mortars, natural aggregates, masonries, among others. These materials are considered as low-quality recycled aggregates, due to poor mechanical properties, namely, their resistance to fragmentation and to wear, and as a result their use in roadway pavement layers is frequently unfeasible. This paper presents the results of a laboratory study on mixtures of a non-selected recycled aggregate with natural and tyre rubber aggregates, with a primary focus on resistance to fragmentation. The study also discusses the fragmentation resistance across different aggregate sizes. The results show that to achieve a meaningful improvement in the fragmentation resistance of the recycled aggregate, it should be blended with very high-quality all-in-aggregates. The addition of tyre-derived aggregate (TDA) to recycled and natural aggregates markedly improves fragmentation resistance; however, the concentration of zinc in the TDA leachate exceeds the regulatory limit. Thu, 01 Jan 2026 00:00:00 GMT https://hdl.handle.net/10216/175336 2026-01-01T00:00:00Z https://hdl.handle.net/10216/175328 Title: Implementação de Ferramentas Lean na Melhoria do Desempenho Operacional da Indústria de Bijuteria Abstract: The increasing complexity of production systems and the need to efficiently respond to market demands make the adoption of continuous improvement methodologies essential in industrial organizations. In this context, this dissertation was carried out at Like a Bee, a company operating in the luxury fashion jewelry industry, with the aim of improving production system performance through the application of Lean principles and Kaizen methodologies. An initial diagnosis of the production process was carried out through direct observation in a Gemba environment, analysis of data extracted from the company's ERP system and collection of operational information. This assessment enabled the identification of several issues, including high levels of Work In Progress (WIP), difficulties in complying with the desired production mix, limited visibility of the production flow and waste associated with non-conformities and rework. Based on the identified problems, several improvement actions were implemented, including the development of Power BI dashboards for performance monitoring, the reorganization of the material request system from the Stock department, the implementation of visual management systems, the application of the 5S methodology in the tumbling sector and the development of a non-conformity monitoring document supported by Kaizen tools, specifically the Ishikawa Diagram and the 5 Why's methodology. In addition, current-state and future-state Value Stream Maps were developed to assess the impact of the implemented improvements. The results obtained, focused on the GoldSmith sector, showed a 22.49% reduction in average weekly WIP, an 11.88% increase in the production mix compliance index and a 21.22% increase in productivity. Furthermore, a reduction of 14.64% in KO non-conformities and 19.88% in rework across the entire factory was achieved. Simultaneously, the implementation of the 5S methodology improved working conditions in the tumbling sector, contributing to a more organized and safer working environment. In a final stage, a REFA analysis was conducted in the assembly sector with the aim of identifying non-value-added activities and opportunities for improvement in work organization. This analysis enabled the identification of several sources of waste and supported the development of improvement proposals focused on their elimination and on increasing operational efficiency. Overall, the results demonstrate the positive impact of the implemented actions on production system performance. Waste reduction, improved production mix compliance and greater production flow stability contributed to increased productivity, demonstrating that the application of Lean principles and Kaizen methodologies is an effective approach to promoting continuous improvement and enhancing competitiveness in highly demanding and quality-oriented production environments. Description: A crescente complexidade dos sistemas produtivos e a necessidade de responder de forma eficiente às exigências do mercado tornam fundamental a adoção de metodologias de melhoria contínua nas organizações industriais. Neste contexto, a presente dissertação foi desenvolvida na empresa Like a Bee, inserida no setor de bijuteria de luxo, com o principal foco em melhorar o desempenho do sistema produtivo através da aplicação de princípios Lean e metodologias Kaizen. Numa fase inicial, foi realizado um diagnóstico do processo produtivo, recorrendo à observação direta em contexto Gemba, à análise de dados provenientes do ERP da empresa e à recolha de informação operacional. Esta análise permitiu identificar diversos problemas, nomeadamente elevados níveis de Work In Progress (WIP), dificuldades no cumprimento do mix produtivo, reduzida visibilidade do fluxo de produção e desperdícios associados a não conformidades e retrabalho. Com base nos problemas identificados, foram implementadas diversas ações de melhoria, destacando-se a criação de dashboards em Power BI para monitorização do desempenho operacional, a reorganização do sistema de pedidos de material ao Stock, a implementação de sistemas de gestão visual, a aplicação da metodologia 5S no setor da Vibração e o desenvolvimento de um documento de acompanhamento das não conformidades suportada por ferramentas Kaizen, nomeadamente pelo Diagrama de Ishikawa e pela metodologia dos 5 Porquês. Adicionalmente, foi elaborado um Value Stream Mapping do estado inicial e do estado futuro, permitindo avaliar o impacto das melhorias implementadas. Os resultados obtidos, focados no setor de GoldSmith, evidenciaram uma redução de 22,49% do WIP médio semanal, um aumento de 11,88% no índice de conformidade do mix produtivo e um aumento de 21,22% da produtividade. Adicionalmente, verificou-se uma diminuição de 14,64% nas não conformidades classificadas como KO e de 19,88% nos Reworks de toda a fábrica. Paralelamente, a aplicação da metodologia 5S permitiu melhorar as condições de trabalho no setor da Vibração, contribuindo para um ambiente de trabalho mais organizado e seguro. Numa fase final, foi realizada uma análise REFA no setor da Montagem, com o objetivo de identificar atividades sem valor acrescentado e oportunidades de melhoria ao nível da organização do trabalho. Esta análise permitiu identificar diversos desperdícios, tendo sido desenvolvidas propostas de melhoria focadas na sua eliminação e no aumento da eficiência operacional do setor. De uma forma geral, os resultados obtidos evidenciam o impacto positivo das ações implementadas na melhoria do desempenho do sistema produtivo. A redução dos desperdícios, a melhoria do cumprimento do mix produtivo e a maior estabilidade do fluxo de produção contribuíram para o aumento da produtividade, demonstrando que a aplicação de princípios Lean e metodologias Kaizen constitui uma abordagem eficaz para promover a melhoria contínua e aumentar a competitividade em ambientes produtivos caracterizados por elevados níveis de qualidade e exigência. Thu, 16 Jul 2026 00:00:00 GMT https://hdl.handle.net/10216/175328 2026-07-16T00:00:00Z https://hdl.handle.net/10216/175327 Title: Economia Circular na Indústria de Prefabricação de Betão: Pavês com um Cimento Ecoeficiente e Agregados Reciclados Mon, 01 Jun 2026 00:00:00 GMT https://hdl.handle.net/10216/175327 2026-06-01T00:00:00Z https://hdl.handle.net/10216/175321 Title: Cooperation in Continuing Education Networks: Option or Destiny? Mon, 01 Jan 2001 00:00:00 GMT https://hdl.handle.net/10216/175321 2001-01-01T00:00:00Z https://hdl.handle.net/10216/175318 Title: EUCEN RECLA Cooperation Thu, 01 Jan 1998 00:00:00 GMT https://hdl.handle.net/10216/175318 1998-01-01T00:00:00Z https://hdl.handle.net/10216/175314 Title: Incorporation of antimicrobial phytochemical-NADES systems into zein electrospun nanofibres for wound dressing applications Tue, 14 Jul 2026 00:00:00 GMT https://hdl.handle.net/10216/175314 2026-07-14T00:00:00Z https://hdl.handle.net/10216/175313 Title: Organizacao da Construcao e de Obras Publicas Mon, 01 Jan 1996 00:00:00 GMT https://hdl.handle.net/10216/175313 1996-01-01T00:00:00Z https://hdl.handle.net/10216/175312 Title: Bioremediation of Emerging Contaminants: A Scale-Up Study of Chlorella vulgaris for Paraben and Microplastics Removal in Wastewater Mon, 13 Jul 2026 00:00:00 GMT https://hdl.handle.net/10216/175312 2026-07-13T00:00:00Z https://hdl.handle.net/10216/169354 Title: A new continuous process for dihydroxyacetone production through glycerol catalytic oxidation Tue, 22 Jul 2025 00:00:00 GMT https://hdl.handle.net/10216/169354 2025-07-22T00:00:00Z https://hdl.handle.net/10216/175302 Title: Continuing Engineering Education (CEE) as Work Based Learning (WBL) Sat, 01 Jan 2005 00:00:00 GMT https://hdl.handle.net/10216/175302 2005-01-01T00:00:00Z https://hdl.handle.net/10216/168731 Title: A Multimodal O-RAN Framework for Intelligent Control of Mobile gNBs Tue, 22 Jul 2025 00:00:00 GMT https://hdl.handle.net/10216/168731 2025-07-22T00:00:00Z https://hdl.handle.net/10216/175294 Title: 9th IACEE conference Tokyo 2004 Thu, 01 Jan 2004 00:00:00 GMT https://hdl.handle.net/10216/175294 2004-01-01T00:00:00Z https://hdl.handle.net/10216/175293 Title: Coordenação de Projectos e Obras Wed, 01 Jan 1997 00:00:00 GMT https://hdl.handle.net/10216/175293 1997-01-01T00:00:00Z https://hdl.handle.net/10216/175290 Title: THEMATIC NETWORK ON UNIVERSITY CONTINUING EDUCATION Wed, 01 Jan 1997 00:00:00 GMT https://hdl.handle.net/10216/175290 1997-01-01T00:00:00Z https://hdl.handle.net/10216/175289 Title: Construction Management and Soft Factors - TUMunique Wed, 15 Apr 1998 00:00:00 GMT https://hdl.handle.net/10216/175289 1998-04-15T00:00:00Z https://hdl.handle.net/10216/175286 Title: International Congress on Occupational Safety and Health in Construction Mon, 01 Jan 2007 00:00:00 GMT https://hdl.handle.net/10216/175286 2007-01-01T00:00:00Z https://hdl.handle.net/10216/175280 Title: E-Cubed Project: Learning Objects Sat, 01 Jan 2005 00:00:00 GMT https://hdl.handle.net/10216/175280 2005-01-01T00:00:00Z https://hdl.handle.net/10216/175275 Title: Safety in Construction - CEE as WBL Sat, 01 Jan 2005 00:00:00 GMT https://hdl.handle.net/10216/175275 2005-01-01T00:00:00Z https://hdl.handle.net/10216/152094 Title: GREENammonia - Development of photo-assisted systems for green ammonia production Fri, 21 Jul 2023 00:00:00 GMT https://hdl.handle.net/10216/152094 2023-07-21T00:00:00Z https://hdl.handle.net/10216/175249 Title: Inovação Digital em Saúde em Contexto de Baixos Recursos: O caso de Moçambique Fri, 19 Jun 2026 00:00:00 GMT https://hdl.handle.net/10216/175249 2026-06-19T00:00:00Z