Selection of elastomeric membranes for the removal of volatile organics from water

A wide range of homogeneous elastomeric membranes has been prepared using dicumylperoxide as a general cross-linking agent. The membranes have been used for both equilibrium sorption measurements and steady-state pervaporation experiments to study solution-diffusion phenomena in the removal of volatile organic components from aqueous solutions. Pervaporation experiments have been performed under identical hydrodynamic conditions in order to fix the boundary layer mass transfer coefficient at a constant and known value. For comparison of the permeabilities of different pervaporation membrane materials, this is of utmost importance. A wide range of selectivity factors up to a value of 100,000 are obtained, whereas usually the permeabilities for the organic component are in the range of 10-10-10-9m2/s and 10-14-10-12m2/s for water. The permeation and sorption data obtained for the various elastomers have been related to the chemical and physical nature of the elastomers through the solubility parameter and the glass transition temperature, respectively. Both diffusional and sorption effects seem to be important, determining the water-transport behavior in the elastomeric membranes. The solubility of the organic component appears to be independent of this combined solubility parameter. Differences in the permeabilities of the organic component can primarily be ascribed to structural parameters in the membrane material, like degree of unsaturation and presence of steric side groups

Compositional structures in mural design : towards a site-specific deconstructive mural methodology

A thesis submitted to the University of Bedfordshire in partial fulfilment of the requirements of the degree of Doctor of Philosophy (PhD)Murals have been the formal visual interpretation of the cultural, social and political life of all ages. Throughout they have been consistently combined with their architectural setting, for example, in ancient Egyptian tombs, in Renaissance churches and on the external walls of buildings in Mexico in the twentieth century. This is a central feature of mural painting. However many contemporary murals do not integrate with their architectural settings, in other words, do not fulfil the site-specificity of the architectural spaces for which they were made. This means that the most important aspect that distinguishes murals from other types of painting is absent. I studied and analysed a number of murals produced in the Italian Renaissance, Baroque and Rococo as this particular period is considered to be not only one of the most significant in the history of art but also a period in which painting and architecture were very closely allied as practices. In particular the radical developments in painting of pictorial space took place along side the developments in architecture. I argue that Renaissance murals could be described, using the terminology of contemporary art, as site-specific art. By identifying the relationship between pictorial space, architectural space and compositional structure I was able to test, through my own practice, the importance of these relationships in understanding the site-specificity of the compositional structure of murals. To address the issue of sitespecificity in murals, I investigated and developed a set of compositional structures through my mural practice that could be applied in the design, execution, and teaching of contemporary mural design. I have developed the notion of a deconstructive method of mural design in which the illusory space of the mural derives its compositional structure from the architectural space in which it sited. I have applied it, tested it and refined it through the execution of a number of hypothetical and live mural commissions. I believe that the approach to the study and practice of mural design I have developed from the perspective of a practice lead researcher contributes to the furtherance of mural design as both a profession and field of study. In particular the identification of compositional structures in mural design and the proposal of a deconstructive method contributes to our understanding of what a mural is as well as current notions of site-specificity in contemporary art

3D FEM Simulation of shape rolling using an ALE method

The shape rolling of stator vanes has been modelled in 3D using the finite\ud element method. Till now only the rolling of straight vanes, which have a constant cross section, is studied. Therefore this rolling process can be considered as a stationary process. Such processes can be described as a flow problem using the Arbitrary Lagrangian Eulerian (ALE) formulation. This makes it possible to follow free surfaces and to adapt the mesh in order to avoid large element distortions, to keep or create refinements were needed. The mesh topology however remains constant during a simulation. Topics of the ALE formulation such as mesh relocation, transfer of state variables etc. will be addressed in the paper. The tools are modelled as deformable bodies, as tool deformation is the most important reason for the deviation of the vane dimensions from the required dimensions. 3D FEM simulations have been carried out of the rolling of a test vane. Some characteristic results, such as material flow, tool deformations, stresses and strains, will be shown

The correlation structure of stationary bilinear processes

Stationary Point;probability theory

Informative sampling in a multivariate linear system disturbed by moving average noise

Systems Theory;mathematics

Tool deformation during the shape rolling of stator vanes

Tool deformation is an important issue in the shape rolling of stator vanes as it directly\ud influences the thickness of the rolled vane. This means that for the design of an accurate production process\ud the deformation of the tools has to be accounted for. The shape rolling of symmetrical straight vanes has been\ud investigated. This rolling process is considered stationary, because these vanes have a constant cross-section\ud over the length. Therefore an ALE formulation is suitable to calculate the steady state. The deformation of\ud the sheet as well as the deformation of the tools have been calculated with the developed finite element model.\ud Some results of these simulations are presented in this pape

3D FEM simulations of the rolling of stator vanes, including tool deformation

Tool deformation is an important issue in the shape rolling of stator vanes as it directly influences the thickness of the rolled vane. This means that for the design of an accurate production process the deformation of the tools has to be accounted for. The shape rolling of symmetrical straight vanes has been investigated. Because these vanes have a constant cross-section over the length, this rolling process can be considered as a stationary process. Therefore an ALE formulation is suitable to calculate the steady state. The deformation of the sheet as well as the deformation of the tools have been calculated with the developed finite element model. Some results of these simulations are presented in this paper