The following is a list of possible projects on offer for the session 2016/17. It is not a complete list, not all of this will run, and other titles can be added later by discussion with interested candidates.

For more details on any of these projects or discussion on other possible topics, contact me:

in person: room 1107

by e-mail to a.fernandez@ee.ucl.ac.uk

by phone: 020 7679 3029 or 020 7679 2000 extn. 3029.

See more details on activities in Computer Modelling in my Home Page at Electronic & Electrical Engineering, University College London

- Automatic and Adaptive Mesh Generation in 2D The subdivision of an arbitrary surface into a number of smaller elements (usually triangles) is a necessary step required in the solution of many engineering problems by the finite element method, - a numerical method that is well suited to computer implementation.
- Dynamics of micro- and nano-particles immersed in Liquid Crystals Particles of micron and nanometer scale are used in colloidal mixtures with liquid crystals in order to enhance their electric and optical properties. Additionally, the elastic interaction between particles and the liquid crystal material provide interesting posibilities for the self assembly of particle conglomerates. This project consists of using the modelling programs developed in our group to study the dynamic behaviour of particles in colloidal mixtures. In particular, we will investigate the effect of the surface anchoring properties on particles of the same or different shapes on the elastic energy of the mixtures and hence, determine the most likely stable states. We' also study the influence of applied electric fields on the movement of these particles.
- Modelling of Optical Waveguides and Devices Waveguide structures are widely used in optics as the basis for active and passive devices. Due to the complicated geometries and material profiles, the exact description of the modal fields cannot be calculated analytically. In some cases only rough approximations are sufficient, but in general, an accurate description of the fields involved will facilitate the understanding of the operation of the devices and permit an accurate design.
- Modelling of cholesteric and blue phase liquid crystals Cholesteric and blue phase liquid crystals are materials that exhibit chirality, which results in an twisted internal structure or of closely packed spirals as in the case of blue phase liquid cryatals. They can be used in devices, taking advantage of fast response times and the fact that they do not need a special surface alignment. The project will consist of using the computer programs developed in the group to analyse these novel structures. Of particular interest is the investigation of stability conditions for the ULH cholesteric mode under different anchoring arrangements and its switching behaviour. Another problem of interest is the switching and the optical behaviour of polymer stabilised blue phase liquid cryatals.
- Optics of liquid crystals The project consists of using computer modelling programs developed in our group to investigate the optical behaviour of liquid crystal devices. It will also use our advanced liquid crystal modelling facilties to characterise the devices. We will concentrate on the study of liquid crystal microlenses and on the design of novel pixel configurations for ultra high resolution LCOS (Liquid Crystal on Silicon) holographic devices.
- Stable states in confined structures In some applications, liquid crystal material is used in holes made in metal structures or other materials. When the LC is in such confined spaces the orientation of the liquid crystal director can adopt several different patterns. This project consists of using the LC modelling tools developed by the group and modelling some of these structures to find the stable states the LC can adopt. Particular attention will be made to the generation and evolution of defects in the LC alignment.
- Flow effects and stability of the pi-cell states Pi cells are liquid crystal cells where the liquid crystal is aligned on the same plane in the two surfaces but splayed. The cells stressed in this way have different stable states and the transition between some of them can be quite fast. For this reason they are interesting for many applications. The project consists of using the computer modelling programs developed in the group to investigate the effect of liquid crystal flow and degree of splay in the pre-tilt on the switching process between the different modes and their stability.
- Visualisation issues in modelling programs Modelling programs produce an enormous amount of data that needs to be post-processed or visualised appropriately to be at all useful. The modelling programs for liquid crystals and for waveguiding structures developed by the group have their own visualisers, some of them quite advanced. However there are always some aspects that need improvement, one of them for example is to add plots of streamlines of some of the variables. Another is to calculate and plot additional quantities, derived from the available results that could be of interest to the user. The project will identify some of these aspects and develop their implementation. The student will need to have a working knowledge of C++
- A Fully Flexible Program to solve the Laplace Equation This project consists of adapting a Laplace solver in 3D, written in the group as part of a larger package for the modelling of liquid crystal devices, to work as a self contained, stand alone application. It will require the addition of a graphical user interface, which can also be adapted from existing programas and visualisation routines, controlled from the user interface and producing graphical output of the results. The student will need to have a working knowledge of suitable programming languages.
- Analysis of Wave Propagation in the Time Domain The finite difference-time domain method (FDTD) is a numerical technique that has attracted much attention in recent times for its ease of use and implementation and for the wide range of problems it can study. This project consists of implementing this method as a computer program and to apply it to the study of some common propagation problems. A computer program has been developed in a previous project and this can be used totally or partially as a starting point for this study.
- Application of Genetic Algorithms in Electromagnetics Genetic algorithms are global optimization methods designed to simulate the natural processes of evolution by genetic recombination and natural selection. This type of approach is particularly suitable to some design and optimization problems encountered in many areas of engineering, specially when the design characteristics are complicated (or even undefined or unknown) functions of the parameters of the problem. This project will explore the application of this method in this context. Possible problems to study are the design of multilayer microwave absorbers and/or the optimization of the sidelobe ratio in nonuniformly spaced antenna arrays.

This project consists of the implementation of an algorithm designed for generating two-dimensional meshes of triangles for finite element analysis. The region of interest is in general a polygon formed by several polygonal subregions containing different materials. The method consists of the successive subdivision of the elements of a starting basic triangulation of the domain, provided as initial data, in accordance to suitably defined criteria. A computer program has been implemented containing some of these algorithms. This project consists of the implementation of some new ideas to perform this task and can either use the existing program as a starting point or start afresh using either MATLAB or C.

The objective of the project is to study modal characteristics of some optical waveguide devices containing liquid crystal substrates. The project will involve the use of computational tools developed in our group specially for this kind of problems. The programs are capable of finding all modes in a waveguide-type structure, and can deal properly with loss (or gain) in the device, anisotropic and inhomogeneous dielectrics, as well as radiation effects in open structures. They can also be used to find the response of a device to a given excitation.

this page: "http://www.ee.ucl.ac.uk/~afernand/projects/3rd-Year/Proj3.html"

*last modified: 2 February 2016*