Applied Mathematics Seminars
During this year we will be continuing with our series of
research seminars organised by the Applied Mathematics Research
Centre
This talk is organised by the West Midlands branch of the IMA
Thursday 17th May 2012
Room AS321D at 18:30
Patterned Segregation: Order out of Complexity
Professor Tom Mullin FRSE FAPS
Director, Manchester Centre for Nonlinear Dynamics
Chair of Institute of Physics Nonlinear and Complex Physics Group
Abstract: Segregation of mixtures of granular materials is a topic which is of interest to a broad range of
scientists from physicists, to geologists and engineers.
An everyday occurrence the phenomenon can be seen at the breakfast table where the fruit and nuts are usually found
clustered at the top of a packet of muesli. The process can be driven by either simple avalanching in binary mixtures
when the angle of repose of the constituents are different or it can be promoted using an external drive or perturbation.
We will discuss these issues and present the results of an experimental study of particle segregation in a binary mixture
which is subject to a periodic horizontal forcing. A surprising self organization process is observed which shows
critical behaviour in its formation. Connections with concepts from equilibrium phase transitions will be discussed.
Wednesday 16th May 2012
Room MF232 at 14:00
How to (un)braid a magnetic field
Dr Gunnar Hornig
University of Dundee
Abstract: Astrophysical magnetic fields often show a complex structure of braided or tangled magnetic flux.
This motivated a series of numerical experiments (Wilmot-Smith et al. 2009, 2010) on the turbulent relaxation
of braided magnetic fields. These experiments have produced relaxed states which in some cases differ drastically
from the predictions of the Taylor hypothesis, that is the assumption that the final state of a turbulent relaxation
is a linear force-free field with the same total helicity as the initial state. We present a method to determine
the topological degree of the field line mapping which shows that there are further constraints on the relaxation
process beyond the conservation of the total helicity (A. Yeates et al., Phys. Rev. Lett. 105, 2010).
These constraints can prevent the system from relaxing to a Taylor state and hence limit the energy which can be
released. This is of interest not only for the problem of heating the solar corona but also for other
relaxation processes in astrophysical and technical plasmas.
Thursday 10th May 2012
Room AS321D at 14:00
Numerical simulation and optimization of the magnet system for the Lorentz Force Velocimetry of electrolytes
Artem Alferenok
Dept of Electrothermal Energy Conversion, Ilmenau University of Technology
Abstract: My presentation is divided into two parts. The 1st part is devoted to introduction of me and of my University.
The 2nd part will contain the information concerning my research. I will explain the working principle of Lorentz
Force Velocimetry (LFV). After that the governing equations and the numerical model using COMSOL Multiphysics will be
discussed. Further, the optimization problem will be formulated and some results will be presented.
LFV is a technique to measure the flow rate of electrically conducting materials. This technique is based
on the interaction of the moving and electrically conducting material with the transversal permanent magnetic field.
In this case, Lorentz force is acting on the magnet system along the flow direction. This force is proportional to
the electrical conductivity and velocity of the moving material as well as to the squared magnetic flux density.
By measuring of this force one can measure the flow rate in the channel avoiding mechanical contact with the flow.
In our project we seek to develop the magnet system for LFV of electrolytes. The main challenge of this development
is tiny Lorentz force (10-100 µN), because of tiny electrical conductivity of electrolyte (4 S/m). Moreover, the
weight of the magnet system is required to be less than 1 kg from the measurement point of view.
Wednesday 9th May 2012
Room MF232 at 12:00
Master Equation Approach to Standard Models of Gene Expression
Thierry Platini
Virginia Tech
Abstract: Stochasticity in the process of gene expression can give rise to variations in protein levels.
These are modeled through different stochastic processes describing the proteins production.
However, obtaining exact analytical results has been an intractable task for all but the
simplest models of gene expression. Starting from the stochastic master equation, we develop, for simple
models of gene expression, an exact mapping allowing us to reach previously known results and new exact
analytical results for time-dependent and steady-state protein distributions.
Friday 4th May 2012
Room AS321D at 14:00
Acoustic streaming flows generated by progressive ultrasound waves in liquids
Valéry Botton
Associate professor at the INSA de Lyon LMFA laboratory
Abstract: The fact that a sound wave propagating in a viscous fluid can be at the origin of steady motions
is known since Faraday and Rayleigh; it is referred to as "acoustic streaming". Our team in Lyon (France
is revisiting this phenomenon in the aim of developing engineering oriented models of acoustic
streaming. This kind of flows is indeed present in applications
such as electro-chemistry and the use of ultrasounds for medical
imaging and care. New fields of application can also be
investigated such as the use of ultrasounds in crystal growth:
this kind of flow can indeed improve heat and mass transfer in
a non intrusive way; it can also be used to control natural
convection instabilities. Similarly to low magnetic Reynolds
number MHD flows, the flows we study here can be considered
as resulting for a weak coupling of an external field and the
fluid motion. The external field is of course the acoustic
field, ruled by propagation laws and the fluid dynamics can
be described by the incompressible Navier-Stokes equation
featuring an "acoustic streaming force" term. The presentation
will give an overview of our approach and results combining
experimental, theoretical and numerical works.
Wednesday 21st March 2012
Room AS124 at 14:00
MHD in tokamaks
Dr Tim Hender
Culham Centre for Fusion Energy
Abstract: This talk will discuss the main MHD instabilities that can occur in the tokamak, explaining their physical causes,
their effects and how they can be controlled or mitigated.
Wednesday 14th March 2012
Room AS124 at 14:00
Numerical simulation and optimization of the magnet system for the Lorentz Force Velocimetry of electrolytes.
Artem Alferenok
Department of Electrothermal Energy Conversion, Ilmenau University of Technology
Abstract:
My presentation is divided into two parts. The 1st part is devoted to introduction of me and of my University.
The 2nd part will contain the information concerning my research. I will explain the working principle of
Lorentz Force Velocimetry (LFV). After that the governing equations and the numerical model using COMSOL Multiphysics
will be discussed. Further, the optimization problem will be formulated and some results will be presented.
LFV is a technique to measure the flow rate of electrically conducting materials. This technique is based on the
interaction of the moving and electrically conducting material with the transversal permanent magnetic field.
In this case, Lorentz force is acting on the magnet system along the flow direction. This force is proportional to
the electrical conductivity and velocity of the moving material as well as to the squared magnetic flux density.
By measuring of this force one can measure the flow rate in the channel avoiding mechanical contact with the flow.
In our project we seek to develop the magnet system for LFV of electrolytes. The main challenge of this development
is tiny Lorentz force (10-100 µN), because of tiny electrical conductivity of electrolyte (4 S/m). Moreover, the
weight of the magnet system is required to be less than 1 kg from the measurement point of view.
Wednesday 7th March 2012
Room AS124 at 16:00
Mythological Networks
Padraig MacCarron
AMRC, Coventry University
Abstract:
Although the distinctions between them are not always sharp, myths
differ from legends and folktales. Mythology entails a plethora of characters
and timeless narratives outside documented history. Legends, on
the other hand, are couched in a definite historical time-frame and folktales
are intentionally fictional.
As in statistical mechanics, there is a notion of universality in the
field of comparative mythology. There, it has been claimed that mythological
narratives from a variety of cultures share the same universal
structure, called the monomyth. For example, the Irish epic Táin Bó
Cúailnge (”Cattle Raid of Cooley”) has been compared to Greece’s Iliad
and the old English Beowulf. Within comparative mythology, such comparisons
can only be qualitative.
We apply network theory to a variety of mythologies in an attempt to
quantify their characteristics and to perform quantitative comparisons.
We interrogate to narratives to determine the social network structures
by looking at the various characters and their interactions. Here we
report on comparisons of the network structures underlying the above
three narratives. We also compare mythological networks to other networks,
both actual and fictitious in an effort to discover where they are
positioned along the spectrum from the real to the imaginary.
Wednesday 22nd February 2012
Room AS124 at 14:00
Simulating flexible polymers in hard disk background potentials.
Johannes Zierenberg
ITP, Uni. Leipzig
Abstract:
We simulate a two dimensional pinned flexible polymer in a disorder
potential consisting of hard disks.
While the polymer is off-lattice, the hard disks are distributed
randomly on a square lattice. We are thus able to
control the arising structures such as cavities and channels.
Throughout the study, we applied two conceptionally different
algorithms, an off-lattice growth algorithm and
a multicanonical Monte Carlo method, in order to cross-check the results
obtained.
While the influence of the potential in the low-density case is merely
marginal, it was possible to show that it
dominates the configurational properties of the polymer for high densities.
Wednesday 7th December 2011
Room AS126 at 16:30
Can't see the trees for the leaves?
Tim Sparks
Coventry University
Abstract: In 2008 I gave a talk to the West Midlands group on my work in phenology, the study of the timing of
natural events, using unusual data sets from often unconventional sources. Three years on, I have moved into a
job at Coventry University but have established solid links with universities in Poland and Germany.
As well as updating some of the material previously presented I will focus on my attempts to create long-term
data series on leafing from dated photographs. There are a number of issues with such photographs which include
their location, quality, distance from the subject, and whether they are colour or black and white. Much of the
presentation will concern work in progress but, so far, I am convinced that this may be a viable method to
assess aspects of environmental change.
[This talk is organised by the Royal Statistical Society West Midlands]
Monday 5th December 2011
Room AS426 at 16:00
Gelation phenomena in cluster-cluster aggregation
Dr Colm Connaughton
Warwick Mathematics Institute and Warwick Centre for Complexity Science
Abstract:
Consider a large cloud of particles which are moved around in space by a random transport process such as diffusion.
If these particles are "sticky" so that they clump together irreversibly upon contact then the resulting distribution
of cluster sizes evolves in time since smaller clusters stick to each other to produce larger ones. The statistical
dynamics of such sticky particles has applications in surface physics, colloids, granular materials, bio-physics and
atmospheric science. It also provides a rich variety of non-equilibrium phenomena for theoretical analysis. One of the
most striking of these phenomena is the so-called gelation transition which, roughly speaking, corresponds to the
generation of clusters of infinite size in a finite time. In this talk, I will discuss the scaling theory of cluster
aggregation at the level of mean field theory and explain the meaning of the gelation transition. At the end I will
discuss the somewhat mysterious phenomenon of "instantaneous" gelation and its relation to some problems in cloud physics.
Wednesday 23rd November 2011
Room AS124 at 14:00
Scientific journals: an attempt of quantitative analysis
Dr Olesya Mryglod
Lviv Polytechnic National University, Institute
for Condensed Matter Physics of the National Academy of Sciences of Ukraine
Wednesday 26th October 2011
Room AS124 at 14:00
Exact enumeration of self-avoiding walks on percolation clusters
Niklas Fricke
Institut fur Theoretische Physik, Universitat Leipzig
Wednesday 12th October 2011
Room AS124 at 14:00
Stochastic description of a bistable frustrated unit
Hannes Nagel
Institut fur Theoretische Physik, Universitat Leipzig
Abstract: Coupled positive and negative feedback loops are often found
in biological systems that support oscillations. Here we consider
genetic regulatory circuits. Two species of proteins A and B interact by
actication/repression of their respective expression: A activates the
production of itself as well as that of B, which in turn represses A.
Starting from a previous deterministic study of that model we chose a
fully stochastic approach to learn about the effect of the inherent
noise in such (typically small) systems.
Monday 23rd May 2011
Room AS136 at 14:00
Some aspects of the thermodynamic equilibrium behaviour of a finite single polymer
near an attractive substrate
Monika Möddel
University of Leipzig
Tuesday 22nd March 2011
Room ASG28 at 15:00
Electromagnetically forced shallow dipolar structure with rotation: 2D or 3D?
Dr Matias Duran-Matute
Laboratoire des Ecoulements Geophysiques et Industriels (LEGI), Grenoble, France.
Thursday 13th January 2011
Room AS433 at 14:00
Direct Statistical Simulation in Fluid Mechanics
Prof Steve Tobias
University of Leeds
Some previously held seminars:
December 2010:-
Coventry University Christmas Lecture
Professor Ian Stewart, University of Warwick
Professor Stewart's Cabinet of Mathematical Curiosities, a surprise Christmas
bestseller in 2008, is now accompanied by his Hoard of Mathematical Treasures. Both
books are mathematical miscellanies for the general public, ranging from one-liners to
mini-essays on the great problems and applications of mathematics. They include
jokes, games, puzzles, and potted mini-essays on important topics. Both are out in
paperback for Christmas 2010.
This lecture will present a selection of their contents, in an accessible and highly
illustrated way.
[This is a joint event organised by BCS Coventry Branch, IET Midlands Area Network,
Coventry University Faculty of Engineering and Computing
and The Institute of Mathematics and its Applications (IMA)]
Corrosion behaviour of pulsed current treated steel and aluminium alloys
Anreas Chrysanthou
Dept of Aerospace,
Civil and Mechanical Engineering,
University of Hertfordshire
November 2010:-
Why are cross products difficult?
Rob Low
Coventry University (AMRC)
In this expository talk I will give an explanation of where the cross
product 'really' lives, in terms of multilinear algebra. The answer
to the title question turns out to be 'Because it is a very special case
of something complicated'.
October 2010:-
Size matters, except perhaps for pure mathematicians
Ralph Kenna
Coventry University (AMRC)
Shape anisotropy of polymers in a disordered environment:
simulations and renormalisation group results
Viktoria Blavatska
Institute for Condensed Matter Physics,
National Academy of Sciences of Ukraine, Lviv
April 2010:-
A Novel Multigrid Approach for Solving Incompressible Navier-Stokes Equations on
Massively Parallel Supercomputers
Yuri Feldman
Tel-Aviv University, Israel
December 2009:-
Coventry University Christmas Lecture:
Aeons before the big bang?
Sir Roger Penrose, FRS
(Event organised by Coventry University.)
November 2009:-
Acoustic streaming flows far from walls
Valerie Botton
INSA, Lyon
From City Centre to Gibbet Hill and back, with traffic jams and back pain
Martine Barons
Complexity Centre
Warwick University
Abstract -
Martine will present a personal perspective on moving between Coventry's two universities and will present two research projects -
one modelling waves in vehicular traffic, and one using machine learning on a complex medical trial dataset.
Mathematical simulation of magnetic pumps
Dr Valery V Denisenko
Institute of Computational Modelling
Russian Academy of Sciences Siberian Branch
Also half-time professor of physics in Siberian Federal University
October 2009:-
Considerations on the fabrication of very small electromagnetic generators
Dr Arnaldo Donoso
Centro de Física,
Instituto Venezolano de Investigaciones Científicas (IVIC),
Caracas 1020A, Venezuela
September 2009:-
Fusion-Energy for the Future?
Anthony J. Webster
Euratom/UKAEA Fusion Association
July 2009:-
On the coarse-graining of stochastic particle systems
Dr Xose Trashorras
Université Paris-Dauphine
May 2009:-
Coupled order parameters on a network: a model for opinion formation
Prof Yurij Holovatch
Institute for Condensed Matter Physics,
National Academy of Sciences of Ukraine, Lviv
March 2009:-
Extended scaling in high dimensions
Jean-Charles Walter
University of Nancy
Using GeoGebra for teaching mathematics
Chris Sangwin
Birmingham University
February 2009:-
Building Earth-like dynamo models
Binod Sreenivasan
Leeds University
Turbulence and transition in liquid metals MHD
Anatolyi Vorobev
Southampton University
Silent Secrets of a Seemingly Simple System: Segregation Patterns in Particle-Laden Rimming Flow
Prof Peter Thomas
University of Warwick
January 2009:-
Magnetoconvection around magnetic flux tubes in the upper solar convection Zone
Dr Gert Botha
University of Warwick
The flow generated by an active olfactory system of the red swamp crayfish
Dr Peter Denissenko
University of Warwick
October 2008:-
Side jets in duct and pipe MHD flows
Prof Bernard Knaepen
Université Libre Bruxelles
September 2008:-
Magnetic field effects on stability of convective flows
Alexander Gelfgat
Tel-Aviv University
June 2008:-
Dynamic Wetting
A Lukyanov
University of Reading
May 2008:-
OpenFoam capabilities for MHD simulation under nuclear fusion technology conditions
Elisabet Mas de Les Valls
Technical University of Catalonia, Barcelona
Modelling Membrane Currents in Heart Cells
Jim Wilson
Canada
Patterns and quasipatterns in parametrically forced systems
Prof Alastair Rucklidge
University of Leeds
title: tba
Maxime Kinet
Université Libre de Bruxelles
Turbulent Patterns
Dwight Barkley
Warwick University
April 2008:-
Spin networks, 6j-symbols and the Ponzano-Regge model of quantum gravity
John Barrett
University of Nottingham
March 2008:-
Molecular simulation and theory of liquid crystals
Prof Michael Allen
University of Warwick
Complex networks and random matrices
Prof Geoff Rogers
Brunel
February 2008:-
Self-similarity in fuse rupture and annular Z-pinches
Jonathan Mestel
Imperial College
Initial value problem for Maxwell equations coupled to a charged dust
Dr Volker Perlick
Lancaster
Dynamo action driven by convective turbulence
David Hughes
Leeds
January 2008:-
Quantum Algebras and Dehomogenisation
Ewan Russell
Coventry
Statistical physics and financial markets
S Jain
Aston
Numerical modelling for the electromagnetic processing of materials
Dr Valdis Bojarevics
Greenwich
November 2007:-
Nanocomposite Photorefractive Polymers for Optoelectronic Application
Farzana Aslam
Department of Mathematical Sciences, Coventry University
The Zero-Range Process: Insights and Applications
Rosemary Harris
London/Saarbrucken
Attractor Based Measures for Monitoring Chaotic Systems
Paul Houghton
Hertfordshire
Kinematics and dynamics of mixing in vortices
Andrew Gilbert
Exeter
non-Abelian Gauge theories and spin transport in materials
Bertrand Berche
Nancy
October 2007:-
Parametric instability of an elongated pool of liquid metal in a low frequency magnetic field
K Spragg
University of Waikato
Zero-energy properties of continuous-spin glasses from a novel optimisation heuristic
Martin Weigel
Symmetric Hopf bifurcation: twisted equivariant degree approach
Zalman Balanov
Netanya Academic College
June 2007:-
Mathematical modelling of ultra-relativistic charge
Robin Tucker
Lancaster University
Velocity measurements in a metal melt driven by a two-phase inductor
Alex Pedcenko
Coventry University
tba
Chris Davies
Cardiff University
May 2007:-
Convection in a strong magnetic field
Svetlana Aleksandrova
Coventry University
Causality, Space-Time, and All That
Robert Low
Coventry University
March 2007:-
Decomposition methods for vector support machines
Bo Zhang
Coventry University
February 2007:-
Non-time orientable manifolds and quantum theory
Mark Hadley
Warwick University
Interfaces and dynamics in colloidal dispersions
Matthias Schmidt
Bristol University
January 2007:-
Sunspots, starspots and stellar dynamos
Nigel Weiss
Cambridge University
A non local shell model of turbulent dynamo
Franck Plunian
LGIT, Grenoble, France
December 2006:-
Metropolis public transport: Network topology and resilience against random and intentional breakdown
Christian von Ferber
Coventry University
Attractor dimension and determining modes in Low-Rm MHD turbulence
Alban Potherat
Technische Universitt Ilmenau
Features of Lattice Animals
Hsiao-Ping Hsu
University of Mainz
Paradox of inductionless magnetorotational instability in a Taylor-Couette flow with a helical magnetic field
Janis Priede
Coventry University
November 2006:-
Scaling relations for logarithmic corrections
Ralph Kenna
Coventry University
Prehistoric demography and the spread of the Neolithic: mathematical models constrained by radiocarbon dating
Anvar Shukurov
Newcastle University
For directions to the Armstrong-Siddeley (AS) Building see the University maps and directions page.