Browsing by Author "Ribeiro, J.E."
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- 2nd. International Workshop on Additive Manufacturing and Sustainability (IWAM): book of proceedingsPublication . Rocha, João; Ribeiro, J.E.; Santos, Jorge; Lima, Rui A.In recent years, the manufacturing processes have undergone a profound transformation, driven by the rapid evolution of additive manufacturing (AM) technologies. What began as a tool primarily for prototyping through stereolithography has now expanded into a versatile and innovative field capable of producing functional, end-use components across a wide range of industries. From fused deposition modeling (FDM) to selective laser melting (SLM) and beyond, AM has unlocked new possibilities in design, material utilization, and production efficiency. Today, additive manufacturing encompasses an extensive array of materials, including metals, polymers, paper, and even biological tissues, enabling applications that span from the mechanical industry to the biomedical sector. One of the most compelling aspects of additive manufacturing is its potential to drive sustainability in modern production processes. Unlike traditional subtractive methods, which often generate significant material waste, AM builds components layer by layer, minimizing excess material and promoting resource efficiency. Furthermore, the ability to use eco-friendly and recyclable materials aligns with global efforts to reduce environmental impact. AM also supports the production of complex, customized parts on demand, reducing the need for large inventories and long-distance transportation, thereby lowering carbon emissions. By optimizing resource use and enabling more efficient production cycles, additive manufacturing is emerging as a cornerstone of sustainable manufacturing practices. This proceeding book arrests the latest advancements, challenges, and opportunities in the field of additive manufacturing, with a particular focus on its transformative potential and contributions to sustainability. The works presented here reflect the interdisciplinary nature of AM, showcasing innovative techniques, materials, and applications that are shaping the future of manufacturing. From cutting-edge research to real-world case studies, this collection aims to inspire further exploration and collaboration, driving the adoption of additive manufacturing as a key enabler of sustainable industrial progress. We invite readers to probe into these pages and discover how AM is not only redefining manufacturing but also paving the way for a more sustainable and efficient future.
- 3D manufacturing of intracranial aneurysm biomodels for flow visualizations: low cost fabrication processesPublication . Souza, Andrews Victor Almeida; Souza, Mauren S.; Pinho, Diana; Agujetas, Rafael; Ferrera, Conrado; Lima, Rui A.; Puga, Hélder Fernandes; Ribeiro, J.E.There is a continuous search for better and more complete in vitro models with mechanical properties closer to in vivo conditions. In this work a manufacturing process, based on a lost core casting technique, is herein reported to produce aneurysm biomodels to perform experimental hemodynamic studies. By us- ing real artery images combined with a lost core casting technique, three materials were tested: paraffin, beeswax and glycerin-based soap. All in vitro biomodels were compared according to their transparency and final structure. Additionally, comparisons between experimental and numerical flow studies were also performed. The results have shown that the biomodels produced with beeswax and glycerine-based soap were the most suitable in vitro models to perform direct flow visualizations of particulate blood analogue fluids. The biomodels proposed in this works, have the potential to provide further insights into the complex blood flow phenomena happening at different kinds of pathologies and answer to important hemodynamics questions that otherwise cannot be tackled with the existing in vitro models.
- Active methodology in mechanical technologyPublication . Ribeiro, J.E.; Barros, Paula Maria; Silva, FloraThe course unit of Mechanical Technology II, which is taught in the 1st semester of the 3rd year, is integrated in the course structure of the Degree in Mechanical Engineering from the School of Technology and Management of the Polytechnic Institute of Bragança. The course contents are organized in fifteen themes that cover different manufacturing processes and which can be classified into two main groups: machining processes and metal joint processes (welding and structural adhesives). The classes of the course unit are divided into theoretical and practical (2 hours each). Usually in the theoretical classes prevail the exposition of contents by the teacher, while the practical classes have an experimental component of design and experimental work that is implemented in laboratory where the students conceive and manufacture real metal components. Considering the analysis of students' performance based on the approval of the course unit, it can be observed that in the academic years prior to 2016/2017 the approval rate was relatively high, for example in the three previous years this rate varied between 78% and 90%. However, if the theoretical component is separated from the practical component is verified that the students in theoretical part have a much lower classification, the percentage of approved classifications ranged from 19% to 42% for the same period. Thus, it is the practical component that essentially contributes to the observed approval rate, and there is doubt if the difficulties of theoretical concepts are overcome at the end of the whole process. In this context, there was a need to rethink new ways of approaching the theoretical component of the course unit that contribute to a greater involvement of the students in the classes and, consequently, to a more meaningful learning of the contents. To reach this objective, in the academic years 2016/2017 and 2017/2018, in the theoretical classes of the course unit the exposition of the themes was carried out by the students instead of traditional mode. In this way, the students were in charge of presenting the theoretical subjects. At the end of each presentation there was a large group discussion in the class, involved the discussion about the application of theoretical contents to practical cases. In order to encourage the student involvement in the debate and the previous study of content, at the end of each class, was proposed a "lesson question", which consisted of a written answer to one or two questions on the topic presented. The main goal of this work is to compare the results of this methodology for two different conditions. In academic year 2016/2017 the class has 15 students while the academic year 2017/2018 the class has 50 students. The analysis of the impact of the described methodology was carried out by the teacher, reflecting on the practice and confronting his experience of teaching the course unit in previous years, based on the students' performance. Was purposed a questionnaire to analyse the student’ opinion about the contribution of the applied methodology to their learning.
- Active methodology in mechanical technologyPublication . Ribeiro, J.E.; Barros, Paula Maria; Silva, FloraChallenged with the existence of increasingly heterogeneous classes in higher education, it is imperative that the teacher reflects on his practice and worries about the learning environment of the curricular units that he/she teaches. This paper describes a teaching experience developed in the Mechanical Technology II course unit, of the degree in Mechanical Engineering, in the 2016/2017 and 2017/2018 academic years. The main objective of the experiment was to achieve a greater involvement of students in the theoretical component of the course unit. Thus, the students were assigned the responsibility of presenting the theoretical subjects in the classes instead of being presented by the teacher as was usual in other years. In addition, in each class, a debate was held on the presentations and the students made a brief written evaluation of the subject. Evaluating the experience, through a questionnaire, the students generally agreed that it was positive for their learning. This is corroborated by the results of the evaluation, since, compared to previous years, there was a significant improvement in the students' classifications in the theoretical component of the course unit.
- Ad-hoc network of smart sensors for mechanical load measurementPublication . Vieira, Manuel; Coelho, João Paulo; Ribeiro, J.E.Strain gauges load cells are transducers devices capable of converting changes in applied mechanical load into an electrical analog signal. Those devices have a large spectrum of applications ranging from domestic to industrial or even medical appliances just to name a few. In this work, they are used in the electronic instrumentation of a force platform that will be used to carry out the analysis and characterization of human biomechanical walking. In this platform, four load cells are installed, each one capable of measuring forces along two different axis. A total of eight strain-gauges per load cell are employed. Hence, analog signal transmission, besides requiring a large number of connection wires, is prone to interference and noise. Moreover, with this solution, scalability requires severe changes in the connection topology. In order to circumvent those problems, an alternative in-situ signal conditioning and digital data transmission system was devised. This approach, as far as investigated, presents an innovative solution to signal conditioning and data transmission for load-cells. In particular, the presented solution allows the creation of an ad-hoc network of load cells, using the I²C protocol with a master interface that allows the users to interact and change the parameters of each load cell. This instrumentation structure has been successfully tested and the obtained results are documented in this article
- Adaptação da UC de Tecnologia Mecânica com recurso às TI em período pandémicoPublication . Ribeiro, J.E.; Braz-César, ManuelEste trabalho apresenta a descrição de uma experiência pedagógica para contornar limitações físicas e de distanciamento social provocadas pela pandemia originada propagação do vírus COVID-19. Nesse sentido, a UC de Tecnologia Mecânica que, anteriormente, que tinha uma componente laboratorial onde os alunos realizavam trabalhos práticos, foi substituída por visitas de estudo, com um número limitado de alunos de cada vez, ao laboratório para assistir a uma demonstração de máquinas-ferramentas. Posteriormente, desenham-nas num software de CAD e simularam os principais movimentos do equipamento. Apesar do entusiasmo dos alunos, quando visitaram o laboratório observou-se, também, uma grande dificuldade em passar dos objetos reais para a modelação tridimensional no software de CAD.
- Additive manufacturing techniques for the fabrication of intracranial aneurysm biomodelsPublication . Rodrigues, D.; Souza, A.; Souza, Maria Sabrina; Ferrera, Conrado; Ribeiro, J.E.; Lima, Rui A.The hemodynamics of intracranial aneurysm (IA) involves complex phenomena that influence its growth and rupture. The advancement of additive manufacturing techniques allowed the development of biomodels suitable for in vitro experimental tests. Thus, we present in this work the process of manufacturing flow biomodels, using different additive manufacturing techniques and materials. The biomodels obtained through these methods proved to be suitable for experiments using imaging techniques and for the validation of numerical studies.
- Advances in Microfluidic Systems and Numerical Modeling in Biomedical Applications: A ReviewPublication . Ferreira, Mariana; Carvalho, Violeta Meneses; Ribeiro, J.E.; Lima, Rui A.; Teixeira, Senhorinha F.C.F.; Pinho, DianaThe evolution in the biomedical engineering field boosts innovative technologies, with microfluidic systems standing out as transformative tools in disease diagnosis, treatment, and monitoring. Numerical simulation has emerged as a tool of increasing importance for better understanding and predicting fluid-flow behavior in microscale devices. This review explores fabrication techniques and common materials of microfluidic devices, focusing on soft lithography and additive manufacturing. Microfluidic systems applications, including nucleic acid amplification and protein synthesis, as well as point-of-care diagnostics, DNA analysis, cell cultures, and organ-on-a-chip models (e.g., lung-, brain-, liver-, and tumor-on-a-chip), are discussed. Recent studies have applied computational tools such as ANSYS Fluent 2024 software to numerically simulate the flow behavior. Outside of the study cases, this work reports fundamental aspects of microfluidic simulations, including fluid flow, mass transport, mixing, and diffusion, and highlights the emergent field of organ-on-a-chip simulations. Additionally, it takes into account the application of geometries to improve the mixing of samples, as well as surface wettability modification. In conclusion, the present review summarizes the most relevant contributions of microfluidic systems and their numerical modeling to biomedical engineering.
- Agora sou eu a expor o tema - abordagem alternativa em tecnologia mecânicaPublication . Ribeiro, J.E.; Barros, Paula MariaA Licenciatura em Engenharia Mecânica, do Instituto Politécnico de Bragança, integra no seu plano de estudos a unidade curricular Tecnologia Mecânica II, que funciona no 1.º semestre do 3.º ano. Os conteúdos programáticos estão organizados em quinze temas que abarcam diferentes processos de fabrico. Esses temas podem ser classificados em dois grandes grupos: processos de fabrico por arranque de apara e processos de ligação de metais (soldadura e adesivos estruturais). As aulas da unidade curricular são divididas em teóricas (2 horas) e práticas (2 horas). Habitualmente nas aulas teóricas prevalece a exposição de conteúdos por parte do professor, já as aulas práticas têm uma componente experimental de cálculo e outra laboratorial, em que os alunos concebem e fabricam peças metálicas reais. Considerando a análise do desempenho dos alunos com base na aprovação à unidade curricular, pode-se verificar que nos anos letivos anteriores a 2016/2017 a taxa de aprovação foi relativamente elevada, por exemplo nos três anos anteriores essa taxa variou entre 78% e 90%. Porém, se se separar a componentes teórica da prática verifica-se que os alunos na parte teórica têm uma classificação bastante mais baixa, a percentagem de classificações positivas variou de 19% a 42% nos três anos letivos anteriores a 2016/2017. Assim, é a componente prática que essencialmente contribui para a taxa de aprovação referida, subsistindo a dúvida se as dificuldades inerentes aos conceitos teóricos são ultrapassadas no fim de todo o processo. Neste contexto, surgiu a necessidade de repensar novas formas de abordagem da componente teórica da unidade curricular que contribuam para um maior envolvimento dos alunos nas aulas e, consequentemente, para uma aprendizagem mais significativa dos conteúdos. Tendo em vista este objetivo, no ano letivo 2016/2017, as aulas teóricas da unidade curricular a exposição dos temas foi efetuada pelos alunos em vez de ser realizada pelo professor. Deste modo, cada aluno ficou encarregado de apresentar um dos temas teóricos. No fim de cada apresentação havia um debate em grande grupo na turma que, para além de pedidos de esclarecimento ao colega que apresentou o tema, envolvia a discussão sobre a aplicação dos conteúdos teóricos a casos práticos. Como todos os alunos tinham também como tarefa a leitura prévia do tema a ser apresentado a sua participação nessa discussão podia ser mais ativa. Visando igualmente incentivar o envolvimento dos alunos no debate e o estudo prévio dos conteúdos, no final de cada aula era, ainda, proposta a "questão de aula", que consistia na resposta escrita a uma ou duas questões sobre o tema apresentado. A análise do impacto da metodologia de abordagem descrita foi realizada pelo professor, refletindo sobre a prática e confrontando com a sua experiência de lecionação da unidade curricular em anos anteriores, com base no desempenho dos alunos nas questões de aula e num questionário que foi proposto aos alunos depois do semestre ter terminado. Este teve como intuito analisar a opinião dos estudantes sobre o contributo da metodologia aplicada para a sua aprendizagem, assim como recolher opiniões sobre alterações a implementar em anos futuros. Quanto à opinião dos alunos, a maioria concorda ou concorda plenamente que a apresentação dos temas pelos colegas aumentou a sua motivação para a unidade curricular e considera que o facto de haver uma avaliação escrita relativa a cada tema aumentou o seu nível de atenção nas aulas e permitiu que o conhecimento sobre os temas ficasse mais sedimentado. Corroborando esta ideia, verifica-se que a classificação global dos alunos na parte teórica foi superior aos anos anteriores já que 78% obteve uma classificação positiva nessa componente. Pelo seu caráter geral, esta metodologia pode facilmente ser aplicada a outras unidades curriculares, seja qual for a área em questão, no entanto poderá ser mais complicada de gerir em turmas de grande dimensão.
- Agora sou eu a expor o tema - abordagem alternativa em tecnologia mecânicaPublication . Ribeiro, J.E.; Barros, Paula MariaFace às aceleradas mudanças culturais que se têm observado na atualidade, torna-se cada vez mais importante que o professor do ensino superior se preocupe com o ambiente de aprendizagem das unidades curriculares que leciona. Neste texto descreve-se uma experiência de ensino desenvolvida na unidade curricular de Tecnologia Mecânica II, da licenciatura em Engenharia Mecânica. O foco principal da experiência foi atribuir ao aluno a responsabilidade de apresentar a componente teórica da unidade curricular e, com base nessa apresentação, promoveu-se o debate em grande grupo sobre os conteúdos. Avaliando a experiência, através de um questionário, os alunos concordaram que ela foi positiva para a sua aprendizagem. Este facto é corroborado pelos resultados da avaliação, na medida em que, comparativamente a anos anteriores, houve uma melhoria significativa das classificações dos alunos na componente teórica da unidade curricular.