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- Use of excess heat from ethylene recycling in a low-density polyethylene production plantPublication . Matos, Rodolfo D. C.; João, Isabel; Silva, JoãoThe recovery of the wasted heat is an effective way of improving the energy efficiency of industry sites and can contribute to the reduction of the operating costs and the CO2 emissions. In the production of low density polyethylene, the polymerisation reaction is carried out with a large excess of ethylene at very high pressure. The excess ethylene is separated at an intermediate pressure (around 280 bar and 310 °C) and then it is recycled. In this recycle, the stream is cooled in several steps to temperatures close to 35 °C before being recompressed. In some units, the first cooling is carried out with air coolers up to temperatures around 130 °C. In a unit with a recycle of 33 t/h, this cooling corresponds to releasing to the atmosphere about 4.6 MW of thermal power. We present a study of different alternatives for the use of this excess heat. We studied the implementation of a refrigeration cycle by absorption with LiBr/H2O, the production of steam and the electricity generation by Rankine and Kalina cycles. The Aspen HYSYS process simulator was used to study the different alternatives. The capital cost was estimated for each of the evaluated options as well as the benefits expected to be obtained. In the study conditions, the absorption refrigeration cycle is the best solution presenting a return period of 3 years.
- Evaluating the degree of gelation of PVC-U pipes. Comparison of currently available methodsPublication . Real, L. E. Pimentel; João, Isabel; Pimenta, S. I.; Diogo, HerminioHealth and Safety policies have led to the recommendation of alternative tests to evaluate the resistance to dichloromethane to estimate the degree of gelation of rigid PVC pipes (PVC-U). In this work, we confirm that DSC is the best alternative method for evaluating the degree of gelation of rigid PVC pipes, using the relation between the enthalpy of fusion of primary and secondary crystallites, which were measured from respective endotherms. The suitability of this method is established by comparison with experimental results obtained with the test for determining the resistance to dichloromethane. Indeed, this method has proven to be fairly reliable and is the only one that allows the quantification of the degree of gelation.
- Exploring students entrepreneurial mindset. Insights to foster entrepreneurship in engineering educationPublication . João, Isabel; Silva, JoãoHigher education graduates have a huge potential forinnovative processes and sustainable economic development. The higher education institutions must play an important role in engaging students for entrepreneurial careers, enhancing their skills in entrepreneurship. Students capable of identifying opportunities and turning ideas into business, who have good communication and leadership skills as well as strong technical competencies are likely to be highly valued in the marketplace. This paper presents the results of a survey to investigate students’ entrepreneurial mindset. The main concern is to understand the interest of the students in entrepreneurship and reasons to start or not start a business, the engineering students’ perceptions of their entrepreneurial related abilities, as well as their perception about the extent by which entrepreneurship is addressed in their engineering programs. The students were selected among two engineering master courses in a Portuguese Engineering School of a Polytechnic Institute. The curricular unit of entrepreneurship is part of the curriculum in one of the master course, while in the other course the students do not have such subject in their study program. The data were collected to investigate differences within and across engineering students who are and who are not participating in entrepreneurship courses as well as diferences concerning some demographic characteristics.
- Designing and teaching a curricular unit to accomplish the outcomes related learning objectivesPublication . João, Isabel; Silva, JoãoThis paper describes how a curricular unit of Advanced Techniques for Quality was designed in the Quality and Environmental Engineering Master Course to satisfy the outcomes defined in the unit. This paper seeks to (1) explain the steps to take into consideration in the design of a curricular unit, (2) explain the outcomes related learning objectives of the specified curricular unit, (3) identify the instructional techniques that are used in the unit to prepare students to achieve those curricular unit outcomes, as well as the selected assessment methods and (4) describe how an active learning project is used as a teaching learning methodology to help the students to attain the learning outcomes defined in the unit.
- TRIZ and MACBETH in Chemical Process EngineeringPublication . João, Isabel; Silva, JoãoThe Chemical Process Industry (CPI) is facing an increasing pressure to develop new or improved chemical processes. The major challenges experienced by CPI is related with sustainability namely economic, social, and environmental issues, is the reason why innovation in chemical process design is becoming more challenging. However innovative chemical process design needs the support of a systematic innovation approach to guide engineers in the creation of new or improved chemical processes. The objective of this work is to present an approach that integrates the theory of inventive problem solving (TRIZ) and a multicriteria decision analysis method MACBETH for the selection of an improved chemical design among different options. The objective is to establish a systematic innovation approach to assist engineers or decision makers through the idea generation with TRIZ theory, and use MACBETH to perform the selection of the best-generated concept. The use of a combined approach in chemical process improvement may increase the efficiency of concept selection avoiding time waste. An illustration is presented in order to show the simplicity and applicability of the approach.
- Designing experiments with Aspen HYSYS simulation to improve distillation systems: Insights from a chemical engineering coursePublication . João, Isabel; Silva, JoãoDesigning experiments by simulation with process simulators, e.g. Aspen HYSYS, can be very effective in the optimization of several chemical engineering systems. It is important to enhance students' skills highlighting the value of applying problem specific knowledge, simulation tools and sound statistical techniques. This paper addresses the use of Aspen HYSYS by Portuguese chemical engineering master students to model distillation systems together with statistical experimental design techniques in order to optimize the systems. The paper presents a procedure followed in two projects beginning with the selection of two case studies from the literature, which the goal is to further improve with the help of design of experiments. The paper presents the work developed by the students in order to model steady-state and dynamic processes and optimize the distillation systems emphasizing the benefits of the simulation tools and statistical techniques in helping the students learn how to learn. Students strengthened their domain specific knowledge and became motivated to rethink and improve chemical processes in their future chemical engineering profession. The main results and conclusions provide a strong incentive from the teachers' perspective to a wider use of this kind of procedure by chemical engineering master students.
- Designing Solutions by a Student Centred Approach: Integration of Chemical Process Simulation with Statistical Tools to Improve Distillation SystemsPublication . João, Isabel; Silva, JoãoProjects thematically focused on simulation and statistical techniques for designing and optimizing chemical processes can be helpful in chemical engineering education in order to meet the needs of engineers. We argue for the relevance of the projects to improve a student centred approach and boost higher order thinking skills. This paper addresses the use of Aspen HYSYS by Portuguese chemical engineering master students to model distillation systems together with statistical experimental design techniques in order to optimize the systems highlighting the value of applying problem specific knowledge, simulation tools and sound statistical techniques. The paper summarizes the work developed by the students in order to model steady-state processes, dynamic processes and optimize the distillation systems emphasizing the benefits of the simulation tools and statistical techniques in helping the students learn how to learn. Students strengthened their domain specific knowledge and became motivated to rethink and improve chemical processes in their future chemical engineering profession. We discuss the main advantages of the methodology from the students’ and teachers perspective.
- Student engagement with statistical design of experiments by active learning projectsPublication . João, Isabel; Silva, João M.This paper illustrates the use of design of experiments in an active learning environment in a new Master course in Quality and Environmental Engineering at a higher education institution in Portugal. The study took place in the unit of Advanced Techniques for Quality. The aim of this work is vto explain how in an active learning environment the students worked on projects designed to use fractional factorial designs in order to improve a system including the impact that the approach had on students. Twelve master students took part of the classroom projects. Three groups of students worked on projects, created and developed by them contributing to increase their commitment and enthusiasm. In a classroom session the students made a presentation and the results were discussed. Each group also produced a video with the planning and execution of the fractional factorial designs which was helpful to start the debate. The active learning approach required that the students developed their own projects and decide when and how to do the experiments. Taking the responsibility of their activities was very enriching forcing the students to think about the things they did and questioning some of their own decisions.
- Patients’ requirements prioritization on the house of quality: the case of glucose monitoring devices in young adults with type 1 diabetesPublication . Dias, Patrícia A.; João, Isabel; Lourenço, João C.The House of Quality (HoQ) is a product development and improvement tool part of the overall process of Quality Function Deployment (QFD), which is widely used by organizations since the late 1960s when Japanese researchers and industrials started to formalize the approach. This paper presents an overview on the use of the HoQ for medical devices applications highlighting a part of a case study where the focus is placed on the prioritization of requirements of glucose monitoring devices from the point of view of young adults with type 1 diabetes. The paper highlights priority ranking issues in the HoQ and makes use of a multi-criteria decision aid (MCDA) approach in order to a proper prioritization and application with HoQ as a support for development and improvement activities.
- The role of teaching decision analysis for sustainability in engeneering schoolsPublication . João, Isabel; Quadrado, José Carlos LourençoThis paper addresses the role that decision analysis plays in helping engineers to gain a greater understanding of the problems they face. The need of structured decision analysis is highlighted as well as the use of multiple criteria decision analysis to tackle sustainability issues with emphasis in the use of MACBETH approach. Some insights from a Portuguese Summer Course on engineering for sustainable development are presented namely the students 'and teacher perceptions about the module of decision analysis for sustainability.