This thesis is dealing with a set of physical phenomena occurring in various block copolymer systems and trying to understand them by means of computer simulation. In the course of the work Cell Dynamics Simulation (CDS) was implemented as a computer program and further developed when necessary. The choice of CDS is due to the fact that it is a simplest minimal model of the Ginzburg-Landau type and its ability to describe complex physical situations was debated. The thesis clarifies this issue by a systematic study of diblock copolymers subjected to the external influences such as electric field, shear flow, confining surfaces and nanoparticles. The thesis results prove that CDS can describe such complex phenomena rather well and therefore, is a complementary method to other more elaborate techniques. The thesis provides a ground for a future development of a tandem simulation where a very fast CDS method can be used as a precursor to more elaborate but slow techniques as, for instance, Dynamics Self-Consistent Field Theory.

Operation of gloveboxes containing radiological hazards relies on risks being broadly acceptable. The operator's protection is maintained in the event of damage to the containment wall or gloves by Vortex Amplifiers (VA's). The VA is a hybrid of the vortex diode and the proportional beam deflection amplifier; two fluidic devices relying on fluid momentum (rather than internal moving parts) to control flow. Further, environmental and fire protection is afforded by inerting the internal glovebox atmosphere utilising Nitrogen or Argon as a constant purging medium. Over the years, ergonomic restrictions have driven VA development towards geometrically scaled-down versions of previously accepted designs. Performance of the new so called mini-VA units was found to be disappointing; investigation of high Oxygen concentrations within gloveboxes identified the mini-VA as being the source. Study of the mini-VA behaviour using smoke visualisation techniques reported here has shown a potential mechanism for leakage from the device control ports into the glovebox. In order to mitigate the leakage and ensure that gloveboxes remain inert and moisture free, increased purging flows are required. The increase in cost of Nitrogen to BNFL is estimated to be in the region of £1 000,000 per year on one plant alone. Very little has been published in respect to back diffusion from VA's or the flow phenomena that cause it. The following work is an experimental and numerical investigation of the physics and characteristic behaviour of mini-V A's, resulting in the development of a potential retrofit mini-VA solution capable of reducing Oxygen leakage by up to 78%. Performance measurements are presented for alternative mini-VA's geometries operating in the incompressible flow regime, with air used as the medium. VA geometry and operating methods have been designed to simulate those used at Sellafield. The effects of both control and supply port geometry on the VA characteristic and VA performance have been investigated utilising both fluid measurement and smoke visualisation techniques. Standard VA performance criteria have been adopted, based upon maximum to minimum flow and pressure ratios. Information gleaned from the physical investigations was used to inform further study using numerical techniques. A commercial Computational Fluid Dynamic (CFD) software 'ANSYS-CFX' was used to conduct further design investigations of the mini-VA geometry. Extensive verification studies are presented demonstrating adequate resolution of the VA geometry utilising an unstructured tetrahedral mesh and detailed representation of the complex anisotropic forces that exist within the VA. Variation in geometric length scales and fluid characteristics were overcome, enabling representation of the complex boundary layers formed within the mini-VA's thin vortex chamber. Consideration has also been given to both quasi-static and dynamic flow conditions. The anomalous reverse flow in the supply ports of the mini-VXA has been captured and instabilities in the vortex core successfully reproduced. This is believed to be the first study capturing numerically the reverse supply flow phenomena in vortex amplifiers. Use of the code was validated against the results of previous physical experimental data. Results of the simulations and physical investigations were used to develop alternative prototype mini­V A geometry. Following a series of tests carried out at Nexia Solutions BTC test facility, Sellafield, leakage characteristics for the prototype mini-VA geometries have been compared with that of the current BNFL mini-VA design geometry. Performance of the proto-type geometries is shown to be significantly better than that of the existing BNFL geometry.

The research reported here investigates the match between child, technology and task in the scenario of children using handwriting recognition software and pen technology to construct writing. Children are an interesting emerging user group who have different requirements from technology to adults. Handwriting recognition technology is one of a range of novel input technologies that has not been widely investigated, and writing is a task that is known to be difficult for children, and for which children use computers in schools. The research was mostly carried out with children aged between six and ten who were in state education. The focus was an investigation of the usability of handwriting recognition technology for use with children, specifically as a replacement for the QWERTY keyboard during the writing process. Specific aims were to determine whether the technology could be used in this way, to identify the usability problems that might arise and to suggest some guidelines for developers who might be making pen-based products for children. The research was also aiming to contribute to knowledge on design and evaluation with children, to add to the literature on the acceptance of errors in recognition-based interfaces for children, to explore the methods that were used for evaluating recognition-based interfaces for text entry and to identify possible future directions for the use of digital text and digital ink to support writing The thesis is that handwriting recognition can be used by children for text input. The thesis document reports a series of empirical studies that identify that the children were able to use the technology, that the rates for recognition were better than expected in most cases, and that the children liked using the pen and tablet. The main usability problems for the child, technology, and task are documented, and a set of design guidelines, that describe some methods by which the usability problems can be overcome, is included. A list of requirements for a recognition-based interface is presented; many of these have been implemented in CobWeb, a prototype-writing environment. The way that children dealt with the errors at the interface is explored, and a tolerance figure for the number of acceptable errors is established. A new taxonomy of errors within the recognition interface is produced, and design solutions are presented for the different types of error. Options for the design of appropriate training for the handwriting recognition interface are explored and some of the difficulties that children have with the interface are examined by looking at the mental models that the children have of the technology and the interface. The work concludes with a discussion of the potential for digital ink for writing and the identification of some areas that might be further developed; these include extensions to the prototype, further work on error handling and work on the design of evaluation studies for handwriting recognition.