Some examples of modeling in chemical engineering: thermal treatment of polymers, phase equilibrium calculations and process design

Presentation submitted to PSE Seminar, Chemical Engineering Department, Center for Advanced Process Design-making (CAPD), Carnegie Mellon University, Pittsburgh (USA), October 2012.

An approach to the application of shift-and-add algorithms on engineering and industrial processes

Different kinds of algorithms can be chosen so as to compute elementary functions. Among all of them, it is worthwhile mentioning the shift-and-add algorithms due to the fact that they have been specifically designed to be very simple and to save computer resources. In fact, almost the only operations usually involved with these methods are additions and shifts, which can be easily and efficiently performed by a digital processor. Shift-and-add algorithms allow fairly good precision with low cost iterations. The most famous algorithm belonging to this type is CORDIC. CORDIC has the capability of approximating a wide variety of functions with only the help of a slight change in their iterations. In this paper, we will analyze the requirements of some engineering and industrial problems in terms of type of operands and functions to approximate. Then, we will propose the application of shift-and-add algorithms based on CORDIC to these problems. We will make a comparison between the different methods applied in terms of the precision of the results and the number of iterations required.

Logic-Based Outer-Approximation Algorithm for Solving Discrete-Continuous Dynamic Optimization Problems

We present an extension of the logic outer-approximation algorithm for dealing with disjunctive discrete-continuous optimal control problems whose dynamic behavior is modeled in terms of differential-algebraic equations. Although the proposed algorithm can be applied to a wide variety of discrete-continuous optimal control problems, we are mainly interested in problems where disjunctions are also present. Disjunctions are included to take into account only certain parts of the underlying model which become relevant under some processing conditions. By doing so the numerical robustness of the optimization algorithm improves since those parts of the model that are not active are discarded leading to a reduced size problem and avoiding potential model singularities. We test the proposed algorithm using three examples of different complex dynamic behavior. In all the case studies the number of iterations and the computational effort required to obtain the optimal solutions is modest and the solutions are relatively easy to find.

Workshops in “Construction of Structures I”: A new teaching methodology in the Building Engineering Degree

Both the current economic situation in the construction sector and the continuous normative changes in the building area imply the use of new methodologies to enhance students’ competences in the degree of Building Engineer. The aim of this paper is to present, analyse and discuss the development of constructive workshops as a new teaching methodology used in the subject of Construction of Structures I at the University of Alicante to complement the constructive and technical knowledge acquired by our students and to enhance their communicative and representation skills essential for their professional practice in the future. The used methodology is based on the development of three-dimensional construction details (in groups of 3 or 4 students) to be shown in two A1-pannels exposed in the corridors of the Polytechnic School. Thus, students’ work approaches constructive problems in a global way by discussing simultaneously with teachers and other groups about the most suitable solution on each case. This contribution has multiperspective results and improves criticism of students in different areas, encouraging new learning strategies and active participation. What is more, on-line information and web applications have been used to prepare and organize this kind of workshops, allowing students to use new technologies as a complementary learning methodology. In conclusion, the use of these new workshops in the Degree of Building Engineer stimulates an interactive class versus a traditional lecture where the participative groups´ attitude and the development of oral presentations dissolve the traditional boundaries regarding public communication skills of the students in the Degree.