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- Sustainable product design education: engineering students’ perceptions and attitudesPublication . João, Isabel; Silva, JoãoMoving towards sustainable development is a global challenge requiring efforts from all the society, but governments and other stakeholders as well as researchers and academics have a central role to aid put in practice the knowledge and tools to enforce the vital changes. This work was developed to better understand the topic of sustainable product design among engineering students given the deficit of such kind of studies in the master courses of our engineering department. Survey data were collected from engineering students enrolled in master courses that have in its syllabus the product design curricular unit. The main objective of the work was to understand the students’ perceptions and attitudes in relation to sustainable product design to envisage actions to continually improve the course with the goal of developing students’ further knowledge and competencies with the focus on cradle to cradle design strategies.
- A thermogravimetric study of HDPE conversion under a reductive atmospherePublication . Costa, Cátia S.; MUÑOZ, MARTA; Ribeiro, M. Rosário; Silva, JoãoThe plastic waste has suffered a dramatic increase and has become one of the biggest environmental problems nowadays. The chemical transformation of plastics by catalytic cracking under hydrogen atmosphere (hydrocracking) is one of the viable solutions to this problem since it can convert plastic residues into petrochemicals and fuels. In this work a thermogravimetric study of high-density polyethylene (HDPE) conversion under hydrogen atmosphere and in the presence of catalysts with different textural and chemical features is presented. The effect of distinct micro (H-ZSM-5, H-FER and H-MOR) and mesoporous (SBA-15 and MCM-41) catalysts is studied, both in terms of energy requirements and products distribution. Moreover, the effects of sample preparation method, catalyst amount, Si/Al ratio and incorporation of a metallic function (Ni and Pt) are also analyzed. The results show that when MCM-41 and SBA-15 mesoporous silicas are added to HDPE no significant changes are observed in terms of the degradation profile. On the contrary, the use of microporous materials decreases significantly the onset of HDPE degradation temperature. The accessibility and acidic content of the materials proved to be the most important factors influencing the HDPE degradation profiles. Moreover, the introduction of a metal function results in a further shift to lower degradation temperatures and favors the liquid products distribution, promoting the formation of gasoline and diesel.
- Excess‐heat recovery and promotion through organic chemical heat pumpsPublication . Silva, Luís António Pinela da; João, Isabel; Silva, JoãoHeat recovery and promotion is essential to decarbonization, and chemical heat pumps based on reversible organic reactions can aid to fulfil this. This paper stud ied the isopropanol/acetone/hydrogen (IAH) and the tert-butanol/isobutene/water (tB/iB) systems regarding their performance and economic competitiveness through simulation and found that the IAH presents satisfactory performance and has the potential to be a very promising solution in increasing the overall energy efficiency while also preventing the emission of massive amounts of CO2 and other greenhouse gases released during energy production and transforma tion. This system presents enough arguments to become a very successful solution if proper politico-economic support and incentives are established and put into practice.
- The role of higher education towards sustainable consumption behavioural change: topics discussed in sustainable consumption educationPublication . João, Isabel; Silva, JoãoMany factors have contributed to the urgency of adopting sustainable consumption patterns. The main challenges related to sustainable consumption include respecting our planet in all its complexity and diversity, taking care of communities and life and, to this end, adopting consumption and production patterns that protect human rights and the well-being of communities. The theme of education for sustainable consumption is multidisciplinary with elements from different curriculum topics and addresses all aspects of everyday life. Establishing a common understanding of sustainable consumption education will create a shared understanding of the topic and improve the necessary cooperation between educators and students, making sustainable consumption education an established and more understandable topic. The objective of this study is to identify the main topics within sustainable consumption education teaching and learning, the main barriers and propose some actions that contribute to a sustainable behavioural change in higher education. A literature review was carried out to categorize the main topics related to teaching and learning processes in higher education environments to fill the gap in this underrepresented research topic of education for sustainable consumption. The review allowed the collection of information reported in this new millennium and the identification, selection and critical evaluation of research related to education for sustainable consumption.
- Bifunctional intimacy and its interplay with metal-acid balance in shaped hydroisomerization catalystsPublication . Mendes, Pedro; Silva, João M; Ribeiro, M Filipa; Daudin, Antoine; Bouchy, ChristopheThe combined impact of platinum location and metal-acid balance on the catalytic performances of HUSY zeolite alumina-shaped bifunctional catalysts was evaluated inn-hexadecane hydroconversion reaction. For well-balanced catalysts, the deposition of Pt in the alumina resulted in lower isomerization selectivity as compared to when platinum was located in the zeolite. In the latter case, the maximal distance between Pt and acid sites was found to be in the nanometric scale (high intimacy) whereas in the former it was in the micrometric scale (low intimacy), particularly due to the presence of large clusters of HUSY zeolite. Nevertheless, whenever proper balance between functions was not ensured in high-intimacy catalysts, the low-intimacy and well-balanced catalysts were shown to perform better. The requirement for nanometric metal-acid sites intimacy must be hence combined with an adequate metal-acid balance to achieve optimal catalytic performance.
- Enhancement of sintering resistance of CaO-based sorbents using industrial waste resources for Calooping in the cement industryPublication . Teixeira, P.; Mohamed, Ismail; Fernandes, Auguste; Silva, João; Ribeiro, M Filipa; Pinheiro, CarlaKeeping a high stability and CO2 capture capacity of CaO-based sorbents during the Ca-looping process is still a challenge. The main goal and the innovative idea addressed in this study consists of investigating if solid industrial waste resources such as a coal fly ash (CFA) and a spent Fluid Catalytic Cracking (SFCC) catalyst, can be used as particle spacers to improve the sintering resistance of two CaO-based sorbents. These two inert industrial waste materials are used in the present work for increasing the CaO particles separation and consequently, reducing their coalescence and hindering severe sintering at the high Ca-looping temperatures. There are currently no studies in the literature on the use of industrial SFCC wastes in blends with CaO based sorbents acting as CaO particles spacer with the objective of reducing the Ca-looping sorbents deactivation along the cycles of carbonation-calcination. Despite the mineralogical and textural differences between the CFA and SFCC catalyst industrial wastes, the tests carried out in a fixed bed laboratory reactor showed that the addition of a small fraction of waste to the CaO sorbent (ca. 10%) seems to be an interesting option to improve the CO2 capture technology efficiency. During the Ca-looping, the volume and stability of sorbent mesopores is essential to achieve higher and stable carbonation conversion values, and since the CFA and SFCC increase the SBET, they contribute to enhance the sintering resistance. The innovative results presented in this study show that the industrial CFA and SFCC wastes have potential to be an economically attractive option thus contributing to reduce the cost of the Ca-looping cycle CO2 capture process, as well as to minimize the adverse environmental impacts of the high volume of industrial wastes generated.
- Bridging the gap between academic and industrial hydrocracking: on catalyst and operating conditions' effectsPublication . Mendes, Pedro S. F.; Silva, João M; Ribeiro, M Filipa; Daudin, Antoine; Bouchy, ChristopheThis work aims at bridging the knowledge gap between the well-studied Pt/zeolite catalysts and the industrially-employed NiMoS/(Al2O3+ zeolite) ones. To do so, catalyst series based on HUSY zeolite were evaluated in the hydroconversion of n-hexadecane under similar operating conditions, but the industrially-relevant H2S and NH(3)contaminants were added when evaluating the latter. The intrinsic performance of Pt/HUSY and NiMoS/(Al2O3+ HUSY) catalysts was noticeably similar, when well-balanced, with the catalytic activity being however much lower in the latter (temperature gap of 125 K). Ammonia inhibition of more than 99% of the protonic sites was revealed to be the origin of such low activity. On the other hand, the metal-acid balance was only reached at sufficiently low reaction temperatures (ca.593 K),i.e.when the NH(3)inhibiting effect increased the metal to acid site ratio in NiMoS/(Al2O3+ HUSY) to values five orders of magnitude larger than those in the Pt/HUSY one. In addition to the understanding achieved on the role of metal-acid balance in industrial-like catalysts and its key controlling parameters, these findings also point to the need to develop better hydrogenating functions to improve the efficiency, and consequently the sustainability of liquid fuel production.
- Synergies, cooperation and other effects: a review for hydroconversion catalystsPublication . Mendes, Pedro S. F.; Silva, João M; Ribeiro, M Filipa; Daudin, Antoine; Bouchy, ChristopheMixing different components is the basis of chemistry. In heterogeneous catalysis, combinations of different active phases are frequently used, but involved in a mysterious way similar to alchemy. The language employed to describe such systems is typically imprecise due to the lack of clear definitions and efforts to quantify the observed performances. In this review, focused in the particular case of bifunctional catalysis, a set of definitions is provided aiming at an analytical and coherent examination of the literature. The works on hybrid zeolite based catalysts for hydroconversion processes are reviewed, and an attempt to classify the various origin of potential cooperation effects is provided. By such means, we hope to provide not only a clear view on the current state-of-the-art on hydroconversion catalysts but also a common framework for a more rigorous investigation of possible synergies of hybrid catalysts over all catalysed reactions.
- Induction heating in nanoparticle impregnated zeolitePublication . Morales Casero, Irene; MUÑOZ, MARTA; Costa, Catia S.; Alonso, Jose Maria; Silva, João M.; Multigner, Marta; Quijorna, Mario; Ribeiro, M. Rosário; De La Presa, PatriciaThe ultra-stable Y (H-USY) zeolite is used as catalyst for the conversion of plastic feedstocks into high added value products through catalytic cracking technologies. However, the energy requirements associated with these processes are still high. On the other hand, induction heating by magnetic nanoparticles has been exploited for different applications such as cancer treatment by magnetic hyperthermia, improving of water electrolysis and many other heterogeneous catalytic processes. In this work, the heating efficiency of gamma-Fe2O3 nanoparticle impregnated zeolites is investigated in order to determine the potential application of this system in catalytic reactions promoted by acid catalyst centers under inductive heating. The gamma-Fe2O3 nanoparticle impregnated zeolite has been investigated by X-ray diffraction, electron microscopy, ammonia temperature program desorption (NH3-TPD), H-2 absorption, thermogravimetry and dc and ac-magnetometry. It is observed that the diffusion of the magnetic nanoparticles in the pores of the zeolite is possible due to a combined micro and mesoporous structure and, even when fixed in a solid matrix, they are capable of releasing heat as efficiently as in a colloidal suspension. This opens up the possibility of exploring the application at higher temperatures.
- Developing an entrepreneurial mindset among engineering students: encouraging entrepreneurship into engineering educationPublication . João, Isabel; Silva, JoãoIt is unquestionable the role of entrepreneurship as a driver of innovation and economic development. The world is dynamically changing and intensively interconnected carrying new challenges and opportunities to the new generation of engineers working in a world where innovation will continue to evolve very quickly. This paper addresses the need to train engineering students to be entrepreneurial engineers considering the global challenges and the role that higher education institutions should play in developing an entrepreneurial mindset among engineering students. The paper presents and discusses the results of a survey carried out in a Portuguese engineering school with the goal of investigate students' entrepreneurial mindsets. The main objective is to understand the extent by which entrepreneurship is addressed in students' engineering programs as well as students' perceptions of their entrepreneurial related skills and the reasons that would lead the students to start or not start a business as well as their perception of the ability to immediately start a business. The results of the study are critically analysed in light of the challenges and opportunities facing future engineers. The work, although limited to a specific context is a valuable starting point for additional research and for the implementation of faculty strategies to improve entrepreneurship education.