Model based robust control approach for batch crystallization product design

The paper presents a novel control approach for crystallization processes, which can be used for designing the shape of the crystal size distribution to robustly achieve desired product properties. The approach is based on a robust optimal control scheme, which takes parametric uncertainties into account to provide decreased batch-to-batch variability of the shape of the crystal size distribution. Both open-loop and closed loop robust control schemes are evaluated. The open-loop approach is based on a robust end-point nonlinear model predictive control (NMPC) scheme which is implemented in a hierarchical structure. On the lower level a supersaturation control approach is used that drives the system in the phase diagram according to a concentration versus temperature trajectory. On the higher level a robust model-based optimization algorithm adapts the setpoint of the supersaturation controller to counteract the effects of changing operating conditions. The process is modelled using the population balance equation (PBE), which is solved using a novel efficient approach that combines the quadrature method of moment (QMOM) and method of characteristics (MOC). The proposed robust model based control approach is corroborated for the case of various desired shapes of the target distribution

Towards constructivist laboratory education: Case study for process control laboratory

Laboratory education is an integrated part of engineering and science degrees. Many research papers refer to poor constructivist learning during the laboratory sessions, indicating the need for reforming the laboratory education in a way that facilitates constructivist learning as well as conceptual understanding. In this paper we present a model of conducting laboratories, based on the well known Kolbpsilas experiential learning cycle, implemented with recent available technologies, and applied to an undergraduate process control lab. There are four main stages in Kolbpsilas model, namely: concrete experience, reflective observation, abstract conceptualization, and active experimentation. To implement these stages, the hands on lab is conducted in conjunction with supplemental activities such as experiments performed in the classroom remotely through the Internet, using virtual lab and preparation sessions, and conducting pre and post lab tests. The paper presents how the supplemental activities are mapped with Kolbpsilas cycle to promote the constructivist laboratory education. The quantitative analysis showed reasonable enhancement of learning outcomes of the experimental groups compared with the control group. The paper presents a novel model of conducting experiential education based on well known pedagogical approach facilitated with recent information and communication technology (ICT) developments

A novel reusable learning object development (RLO) for supporting engineering laboratory education

A novel reusable learning object development (RLO) for supporting engineering laboratory educatio

Graphical processing unit (GPU) acceleration for numerical solution of population balance models using high resolution finite volume algorithm

© 2016 Elsevier LtdPopulation balance modeling is a widely used approach to describe crystallization processes. It can be extended to multivariate cases where more internal coordinates i.e., particle properties such as multiple characteristic sizes, composition, purity, etc. can be used. The current study presents highly efficient fully discretized parallel implementation of the high resolution finite volume technique implemented on graphical processing units (GPUs) for the solution of single- and multi-dimensional population balance models (PBMs). The proposed GPU-PBM is implemented using CUDA C++ code for GPU calculations and provides a generic Matlab interface for easy application for scientific computing. The case studies demonstrate that the code running on the GPU is between 2–40 times faster than the compiled C++ code and 50–250 times faster than the standard MatLab implementation. This significant improvement in computational time enables the application of model-based control approaches in real time even in case of multidimensional population balance models

TriLab – a combined remote, virtual and hands-on laboratory as a novel reusable learning object (RLO) for supporting engineering laboratory education

Reusable Learning Object (RLO) is, in brief, a conceptual model of a shared vessel of teaching and learning content which is normally developed using IT tools. Attention have been paid recently towards using RLOs in educational processes for facilitating better learning and minimizing costs associated with improving teaching and learning. The importance of a laboratory experience in engineering education curricula has been emphasized in a large number of science and engineering education articles (Johnstone et al 2001; Hofestein et al 2004; Feisel et al 2002; Kirschener et al 1988; Ma et al 2006). Wankat observes that only 6% of the articles published in the Journal of Engineering Education from 1993-2002 had ‘Laboratory’ as a keyword (Wankat 2004). In response to the recent recommendations in the literature regarding the engineering laboratory education, we worked on developing an Online Laboratory Learning Object (OLLO) for enhancing the students laboratory experience, the OLLO was developed for the process control laboratory taught through various courses at the chemical engineering department of Loughborough University

Aspect ratio distribution and chord length distribution driven modeling of crystallization of two-dimensional crystals for real-time model-based applications

Two-dimensional (2D) crystals, for which the shape is described by two linear sizes, are common in fine chemical and pharmaceutical industries. Since the crystal size and shape are directly related to the performance of active pharmaceutical ingredients, the simultaneous size and shape distribution control is of paramount importance in pharmaceutical crystallization engineering. To efficiently achieve simultaneous size and shape control often requires model-based control strategies; however, the increased computational cost of the process simulation and the substantial differences between the simulated and measurable quantities make the implementation of model-based control approaches challenging. This paper addresses the important problem of the real-time simulation of the most likely measurable chord length distribution (CLD) and aspect ratio distribution (ARD) as well as the concentration variations during the crystallization of 2D needle-shaped crystals. This enables the application of focused beam reflectance measurement (FBRM) and particle vision and microscopy (PVM), two routinely applied probes, as quantitative direct feedback control tools. Artificial neural network (ANN)-based FBRM and PVM soft-sensors are developed, which enable the direct and fast transformation of 2D crystal size distribution (CSD) to CLD and ARD on arbitrary 2D grids. The training data for the ANN are generated by a first principle, geometrical model-based simulation of FBRM and PVM for high aspect ratio crystals, although the ANN approach is applicable for any simulated or experimental training data sets. It is also demonstrated that the in situ imaging-based shape measurement underestimates the real aspect ratio (AR) of crystals, for which a simple correction is proposed. From the model-equation solution perspective, the soft-sensors require full population balance solution. The 2D high-resolution finite volume method is applied to simulate the full 2D CSD, which is an accurate, stable, but computationally expensive technique. The real-time applicability is achieved through various implementation improvements including grid optimization and data-type optimized hybrid central processing unit-graphical processing unit calculations

Applying Kolb’s experiential learning cycle for laboratory education

This paper describes a model for laboratory education based on Kolb’s experiential learning theory. The method is implemented using modern teaching technologies and a combination of remote, virtual, and hands-on laboratory sessions and have been applied to the teaching of the undergraduate process control laboratory at the Chemical Engineering Department at Loughborough University, United Kingdom. An argument that poor learning in the laboratory is due to insufficient activation of the prehension dimension of Kolb’s cycle was suggested and verified, providing a pedagogical explanation. The quantitative analysis showed significant enhancement of the learning outcomes of the experimental group compared with the control group. Apart from the hands-on session, the proposed model involves additional activities, such as pre- and post-lab tests and virtual laboratory sessions, which are associated with Kolb’s cycle to facilitate constructivist learning. The paper provides the first laboratory education model that builds thoroughly on Kolb’s experiential learning theory

Beyond the classroom walls: remote labs, authentic experimentation with theory lectures

Recent calls of constructivist pedagogy emphasize the role of delivering education in more authentic and real contexts. It urges the change of the classical classroom lecture model towards more active participation of the students. Engineering is to large extent an applied science, it is very important to be taught in its genuine context rather than the current more theory oriented model. One important issue is to support the classroom theoretical lectures with real applications. Laboratories are provided essentially as core part of engineering education as a platform of showing the applicability of theory into practice, however, most labs are not portable and can not be moved into the classroom to show the links between theory and practice in real time. One solution is close the distance through remote operation of the lab rig during the lecture. This approach is also useful in enriching the number of utilized rigs through sharing among institutes. This paper reports on the approach of utilizing and sharing remote experimentation for classroom theoretical lectures. It also reports the students opinion towards the novel approach

Beyond the engineering pedagogy: engineering the pedagogy, the game of experiential learning

Modern constructivist pedagogical research emphasizes developing studentcentred educational practices. This requires students to do extra effort and they should be equipped with the motivation to conduct such extra work load. However, the situation is dilemmatic since many students (in particular, undergraduates) tend to do their studies with the minimum effort needed to reach their goals. In this paper we analyse this dilemma from the game theory perspective, where we try to find conditions where students are willing to voluntarily take extra course work. We model the strategic interaction between the student and the teacher by a 2x2 non cooperative game. We suggest a mechanism for transferring the game equilibrium into the desired one, i.e. experiential learning equilibrium. We also show an experiment for identifying the energy needed to shift the equilibrium towards the desired one. The paper presents one of the very few game theoretical models that were developed in pedagogical research

Beyond the engineering pedagogy: engineering the pedagogy, modelling Kolb’s learning cycle

Experiential Learning is a modern radical approach of conducting education. Kolb’s four stages experiential learning model have been well received since it was proposed during mid 1980’s. In this paper, we approach the analysis of Kolb’s Cycle from an engineering point of view, where we develop a mathematical model of the learning curve when Kolb’s experiential learning cycle is use. Furthermore, we analyse the characteristics of the derived model for example, learning stability and learning robustness. We conclude with set of important characteristics of Kolb’s cycle that we could clearly explore after utilizing the control engineering tools. The most important characters are accommodating the uncertainties of the students learning ability. This paper is one of the few trials traced in the pedagogical literature where control engineering methods are applied for studying pedagogical process