Dr David M. Lewis

Personal Details

Full name: David Mark Lewis.
Date of Birth: 6th August 1966
Telephone: 0151 794 4014 (Work), 07760202270 (Mobile).
E-mail: d.m.lewis@liv.ac.uk

Education

Wakeman School, Shrewsbury 1977-82. Shrewsbury Sixth Form College 1982-84.
University of Nottingham 1984-91.
1987 BSc in Mathematical Physics. First Class Honours.
1991 PhD in Mathematics for thesis entitled The Autoionization of the Muonic Quasimolecule. Supervisor Dr E. A. G. Armour.

Employment Record

Research Associate at the University of Sheffield, working with Professor P. C. Chatwin, September 1991-September 1996.
Temporary Lectureship at City University, January 1997-September 1998.
Senior Research Associate at the University of Cambridge, working with Professor T. J. Pedley, F.R.S., October 1998-March 2001.
Research Associate at the University of Reading, working with Dr S. E. Belcher, June 2001- Aug 2002.
Lecturer in Applied Mathematics at the University of Liverpool, Sept 2002-date.

Research Achievements
The subject of my PhD thesis was a specific study of one of a series of reactions culminating (under the right conditions) in muon catalysed fusion. The work involved a thorough understanding of the quantum mechanics of atoms and molecules, some scattering theory and the application of various computational techniques, e.g. the Kohn variational method. I was able to model the latest experimental measurements of the fusion rate well, confirming the postulated evolution and quantity of energy generated by the reaction. My work provided the basis of further theoretical work in the subject, both in Nottingham itself and in Moscow.

At Sheffield I worked in a research team investigating the release and dispersion of potentially hazardous contaminants into the atmosphere. The work involved fluid mechanics (especially turbulence), numerical methods (including extensive computation) and statistics. In particular I formulated a model of the probability density function of concentration based on physics, with the parameters adjusted to account for different atmospheric and source characteristics. Ultimately this work should form a basis for further models of hazard assessment. I developed a simple computer model of concentration fluctuations and dosage based on these theoretical ideas. Tests of the computer model against experimental data showed good agreement and it is currently in use at the Chemical and Biological Defence Establishment (CBDE), who sponsored this project. The development work involved the application of various data processing techniques in order to study the results of experiments taken in the field. I adapted a technique previously used in astronomy to remove background noise which otherwise corrupt the resulting datasets. The field trials were often carried out by staff of the CBDE and I was involved in the planning of some of these experiments. Data from experiments sponsored by the EC Environment programme was also used in these studies. At City University I extended this work, which was originally based primarily on steady releases of contaminant, to the study of the dispersion of clouds resulting from instantaneous releases.

I went to the University of Cambridge to work on a project looking at the problem of modelling the behaviour of plankton in the ocean. My previous experience of studying turbulence and viewing its effects from a statistical point of view has been of great help in understanding the movements of these microscopic animals. In particular I have being looking at the inter play between their swimming movements and the turbulent fluid motion in relation to the problem of searching out and catching their prey. In addition, I have been studying the effects of gyrotaxis and turbulence on the orientation of a micro-organism as it swims through the ocean. I would like to extend this work to develop more general models of planktonic populations, incorporating both small and large scale turbulent features, of which there is a distinct gap in the published literature. At Reading University I worked on a project studying the effects of winds and waves on the ocean mixed layer. Specifically I used Large Eddy Simulation methods to study the nature of Langmuir circulations generated by the Stokes drift, as against the more conventional shear generated turbulence. The upper ocean mixed layer is where phytoplankton species obtain light for photosynthesis and is home to many species of predatory zooplankton, so understanding its dynamics will be crucial in the development of new population models. I have continued to work on these problems since joining Liverpool University.

PhD Project

The Influence of Prey Distribution and Turbulence on Plankton Predation.

Publications

Armour, E. A. G. and Lewis, D. M., De-excitation of the 'nucleus' of the Muonic Quasimolecule, , by emission of an Auger electron J. Phys. B 23, L25 (1990).
Armour, E. A. G., Lewis, D. M. and Hara, S., Calculations of the Auger de-excitation rate of within the Muonic Quasimolecule Phys. Rev. A 46, 11, 6888-6893 (1992).
Lewis, D. M., and Chatwin, P. C., The Treatment of Atmospheric Dispersion Data in the presence of Noise and Baseline Drift, Boundary-Layer Meteorology, 72, 53-85 (1995).
Robinson, C., Lewis, D. M. and Chatwin, P. C., The Pitfalls of Thresholding Atmospheric Dispersion Data, Boundary-Layer Meteorology, 73, 183-188 (1995).
Lewis, D. M. and Chatwin, P. C., A New Model PDF for Contaminants Dispersing in the Atmosphere, Environmetrics, 6, 583-593 (1995).
Chatwin, P. C., Lewis, D. M. and Mole, N., Practical Statistical Models of Environmental Pollution, Mathematical and Computer Modelling, 21, 11-14 (1995).
Chatwin, P. C., Lewis, D. M. and Sullivan, P. J., Turbulent Dispersion and the Beta Distribution, Environmetrics, 6, 395-402 (1995).
Chatwin, P. C., Lewis, D. M. and Mole, N., Atmospheric Diffusion: some new Mathematical Models, Advances in Computational Mathematics, 6, 227-242 (1996).
Lewis, D. M., Chatwin, P. C. and Mole, N., Investigation of the Collapse of the Skewness and Kurtosis exhibited in Atmospheric Dispersion Data, Il Nuovo Cimento, 20 C, 385-398 (1997).
Chatwin, P. C., Lewis, D. M. and Mole, N., Comments on the Properties and Uses of Atmospheric Dispersion Datasets, Il Nuovo Cimento, 20 C, 475-489 (1997).
Lewis, D. M., and Chatwin, P. C., A Three-Parameter PDF for the Concentration of Atmospheric Pollutant, Journal of Applied Meteorology, 36, 1064-1075, (1997).
Lewis, D. M., Monte Carlo estimates of the Dosage for Releases of Potentially Toxic Gases into the Atmosphere, Environmetrics, 8, 629-650 (1997).
Lewis, D. M., A Simple Model of Concentration Fluctuation in Neutrally Buoyant and Dense Gas Clouds, Boundary-Layer Meteorology, 90, 117-153 (1999).
Lewis, D. M. and Pedley, T. J., Planktonic Contact Rates in Homogeneous Isotropic Turbulence: Theoretical Predictions and Kinematic Simulations, Journal of Theoretical Biology, 205, 377-408 (2000).
Lewis, D. M. and Pedley, T. J., The Influence of Turbulence on Planktonic Predation Strategies, Journal of Theoretical Biology, 210 347-365 (2001).
Lewis, D. M., The Orientation of Gyrotatic Spheroidal Micro-organisms in a Homogeneous Isotropic Turbulent Flow, Proceedings of the Royal Society A, 459 1293-1323 (2003).
Lewis, D. M., Planktonic Contact Rates in Homogeneous Isotropic Turbulence: The Case of Predators with limited Fields of Sensory Perception, Journal of Theoretical Biology, 222, 73-97 (2003).
Lewis, D. M. and Belcher, S. E., Time-dependent, Coupled, Ekman Boundary Layer Solutions incorporating Stokes Drift, submitted to Dynamics of Atmospheres and Oceans.
Polten, J. A., Lewis, D. M. and Belcher, S.E., The role of wave induced Coriolis-Stokes forcing on the wind driven mixed layer, submitted to Journal of Physical Oceanography.