Abstract: Control moment gyros (CMGs) are momentum exchange devices which are considered to be good actuators for spacecraft due to their fast slewing capabilities. They consist of  systems of gimballed momentum wheels. Singularities occur when, no matter how the gimbal angles are moved, the angular momentum cannot be increased in a given direction. We analyze the relationship between gimbal angles and the angular momentum for different CMG  geometries to understand the different types of singularities which occur in these systems.

Abstract: Our intention is to show the Gardner method for generation of conservation laws for partial difference equations. We apply it to all the ABS equations and to an asymmetric quad-graph equation. We also show that the Gardner method can be applied for symmetries. Namely, we use it to generate an infinite number of symmetries from known one.

Abstract: As formation flying missions are becoming a reality, relative motion modelling has received an enhanced interest through the past decade. 

Abstract: TBA

Abstract: It is seen in some natural biological situations, that a living organism requiring a change in its location and orientation is able to do so by executing a sequence of internally controlled motions. These motions cause a resultant location change due to the conservation of momentum.

Abstract: TBA

Abstract: The non-linear wave equation (sometimes called the non-linear Klien-Gordon equation) is a much studied equation with applications in Josephson transmission lines, dislocations in crystals, DNA processes and much more.  It possess many types of solutions which may include stationary front solutions.  In this talk we shall consider what effect adding a step-like inhomogeneity has on the stability of such fronts and present some of the results we have derived over the last three years.

Abstract: TBA

Abstract: Liquid crystals are fluids carrying an orientational degree of freedom. Their rotational symmetries can be used to reduce their Lagrangian description. This talk shows how Euler-Poincaré reduction produces a unifying framework for liquid crystal dynamics. As a result, two major liquid crystal theories turn out to be equivalent. Moreover, these theories can be extended to deal with orientational defects, aka disclinations.

Abstract: 

Models describing waves in anisotropic media or media with imperfections
usually have inhomogeneous terms. Examples of such models can be found
in many applications, for example in nonlinear optical waveguides, water
waves moving over a bottom with topology, currents in nonuniform
Josephson junctions, DNA-RNAP interactions etc. This talk considers the
effects of (non-local) inhomogeneities on the existence and stability of
fronts in nonlinear wave equations.

This seminar is part of the virtual AG (Access Grid) Dynamics Seminar
series, a series of occasional seminars intended for those interested in
Nonlinear Dynamics and Dynamical Systems who have Access Grid facilities
(as used in the MAGIC network). More information can be found at
http://www1.maths.leeds.ac.uk/~alastair/ag_dynamics_seminar/

People in Surrey can attend the talk in real-time and life in the
Computing AGN room 39BB02. It would be nice if some people could go
along so that the seminar room is not too sparse.

Abstract: TBA

Abstract: TBA

Abstract: A molecular motor is a nano-scale protein which converts chemical energy into mechanical work. For example, myosin-V is a double headed processive molecular motor that transports a variety of cargos within biological cells. It achieves this by walking head-over-head along an actin track, passing through a sequence of coordinated biochemical reactions and mechanical motions, taking several successive steps before detaching.

There is much debate as to the exact nature of the stepping mechanism of myosin-V due to the noise to which nano-scale measurements are subject. Mechanochemical aspects have been experimentally investigated and averaged quantities, such as velocities and run lengths, have been measured. This work focuses on theoretical methods to extract more information - such as a more precise stepping mechanism - from these experimental results aiming to improve the quality of molecular motor modelling.

Abstract: In this talk I will review my previous work on stability and mixing in two-dimensional vortices. This will include a threshold calculation for the existence of nonlinear cat's eye structures and an investigation into nonlinear vorticity staircase structures in a Gaussian vortex.

Abstract: The fact that piecewise contractions are asymptotically periodic was proved in 2008. This general result raises further questions about the periodic dynamics displayed by piecewise contractions, and the seminar takes a close look at a family of periodic solutions to a particular mapping, the two-halfplane map, and constructs the sets of parameters where the family exists, in the limit of strong contraction. As the family chosen is only one among many, the talk concentrates on techniques for constructing the parameter sets in the hope that these can be employed in further studies of the problem.

Abstract: Subject of this talk is the twistor geometry discussion of a five-dimensional generalisation of the instanton equation known as the contact instanton equation. This equation was recently introduced in the context of (twisted) supersymmetric Yang-Mills theory on the five-dimensional sphere. If time permits, certain extensions to higher dimensions and supersymmetric generalisations will also be presented.

Abstract: We will discuss special quantum group symmetries of the integrable system associated to the AdS/CFT correspondence and its quantum deformations.

Abstract: The asymptotic behaviour of the random (Markovian) walk on the integers in a randomly generated environment of transition probabilities was first characterised by Solomon in the setting where jumps  are restricted to {+1,-1}. Subsequent work by Key extended this characterisation to the setting where jumps are uniformly bounded, while Balthausen and Goldsheid achieved similar results in the more general setting of the strip k x Z (k \in N). We consider a deterministic version of this problem in which the Markov assumption is relaxed, and establish a zero-one law for the deterministic walk in a deterministic environment (DWDE).