Research
My main area of research is computational modelling and optimisation applied to diverse problems in chemical engineering including energy, systems biology and process operations. This is exemplified by the following papers:
Wilkinson et al. (1995,1996) introduced a novel mathematical technique for tackling large discrete optimisation problems which are often encountered in scheduling flexible production processes. The technique I developed was to rigorously aggregate or lump together constraints and variables in order to create approximate problems that are smaller and much easier to solve. This technique has been incorporated into commercial software.
In Wilkinson et al. (2008) I created a novel method for fitting over-parameterised dynamic models to sparse experimental datasets using sequential linear programming. The method uses mathematical regularisation in which prior parameter values are used to constrain the parameter search. This is a general technique which has been effective on systems biology models in several published studies.
Dimelow and Wilkinson (2009) looked at the fundamental problem of how translation of proteins is initiated and controlled in eukaryotes. We analysed experimental data from yeast mutants by developing a detailed mathematical model. We identified the two most important rate limiting steps in the network which, encouragingly, were in agreement with experimental results obtained by other research groups.
In Liu et al. (2013) we carried out an experimental investigation to optimise productivity of biofuels – in particular algal lipids. Unlike previous studies which tended to focus solely on the lipid fraction of the algal biomass and/or the growth rate, we recognised that volumetric productivity also depends on the maximum biomass density that can be achieved.
The bioenergy theme was continued in Al-Mashhadani et al. (2015,2016) in which we used CFD modelling to show that very small bubbles (< 100 microns) can give a step change in the performance of airlift reactors for biochemical applications. Interestingly, this work came before such small 'microbubbles' could be reliably made but has driven the development of better technology for sub 100 micron microbubble generation by companies such as Perlemax Ltd. For a considerable length of time it was the most downloaded paper in Chemical Engineering Science.
Finally, the results presented in Liang et al. (2023) use a novel headspace mass balance to demonstrate how pressurised anaerobic digestion can increase the energy content of the biogas. The major benefit of this work is to reduce upgrading costs which are the major part of bio-methane production, thereby offering the potential to transform the economic viability of the process.
Selected Publications
Liang, Z., Wilkinson, D.W., Wang, C. & Wilkinson, S. J. (2023). Pressurised Anaerobic Digestion for Reducing the Costs of Biogas Upgrading. Bioenerg. Res. https://doi.org/10.1007/s12155-023-10602-w
Al-Mashhadani, M. K., Wilkinson, S. J., & Zimmerman, W. B. (2016). Carbon dioxide rich microbubble acceleration of biogas production in anaerobic digestion. Chemical Engineering Science, 156, 24-35.
Al-Mashhadani, M. K., Wilkinson, S. J., & Zimmerman, W. B. (2015). Airlift bioreactor for biological applications with microbubble mediated transport processes. Chemical Engineering Science, 137, 243-253.
Liu, J., Mukherjee, J., Hawkes, J. J. and Wilkinson, S. J. (2013). Optimization of lipid production for algal biodiesel in nitrogen stressed cells of Dunaliella salina using FTIR analysis. J. Chem. Technol. Biotechnol. doi: 10.1002/jctb.4027
Brown, M., He, F., & Wilkinson, S. J. (2010). Properties of the proximate parameter tuning regularization algorithm. Bulletin of Mathematical Biology, 72(3), 697-718.
Dimelow, R. J., & Wilkinson, S. J. (2009). Control of translation initiation: a model-based analysis from limited experimental data. J R Soc Interface, 6(30), 51-61.
Wilkinson, S. J., Benson, N., & Kell, D. B. (2008). Proximate parameter tuning for biochemical networks with uncertain kinetic parameters. MolBiosyst, 4(1), 74-97.
Wilkinson S. J., Cortier A., Shah N. and Pantelides C. C. (1996). Integrated Production and Distribution Scheduling on a Europe-Wide Basis, Computers chem. Engng., 20, S1275-S1280.
Wilkinson S. J., Shah N. and Pantelides C. C. (1995). Aggregate Modelling of Multipurpose Plant Operation, Computers chem. Engng., 19, S583-S588