The rheology of collapsing zeolites amorphized by temperature and pressure

Greaves, G.; Meneau, F.; ap Gwynn, I.A.; Wade, S., (2003). The rheology of collapsing zeolites amorphized by temperature and pressure. Nature Materials 2, 622-629. RAE2008

Forensic analysis of analgesics by TLC

An introductory laboratory on the identification of analgesics in an unknown sample. Ideal for the first week of an organic chemistry sequence to get students familiar with their surroundings. Students extract, isolate, and perform thin layer chromatography on aspirin, acetominophen, or ibuprofen.

Behind the paravent: a study of Konrad Bayer's dramatic texts

This thesis is a study of Konrad Bayer's dramatic texts. It has evolved out of various attempts to read those texts, some filed and some more successful. It does not claim to be authoritative or complete, since the nature of Bayer's texts, as will become clear in the course of the ensuing chapters, means that they resist such an interpretation. To accept this was an important prerequisite for the writing of this thesis, but a difficult one to fulfill because for the Bayer commentator it constitutes a certain acceptance of defeat even before one begins. Chapter 1 will begin by providing some introductory information about Konrad Bayer, including details of his life and his membership of the Wiener Gruppe, a formative phase in his development as a writer. It will also consider the historical and cultural climate of 1950s Austria that provided the backdrop for Bayer's literary work. The phenomenon of the Wiener Gruppe will then be examined against the background of preceding experimental movements, for the purpose of situating Bayer's work historically and artistically. The aim of this historical and artistic survey is to prepare for the confrontation with Bayer's texts that makes up the other chapters of the thesis. Chapter 2 will constitute a close textual study of one of Bayer's dramatic texts using criteria from the field of text linguistics. Such a study will offer an entry point into Bayer's texts and will supply material which will form the basis for the interpretative investigations of the chapters that follow it. Chapter 3 will consider the influence of language and the individual. In chapter 4 the figure of the Lion of Belfort, a recurring figure in Bayer's dramatic texts, is discussed. The final chapter of this thesis will examine the recurring motifs of violence and cannibalism and will consider them in terms of the findings of preceding chapters.

Multi-scale modelling of atomic layer deposition

High-permittivity ("high-k") dielectric materials are used in the transistor gate stack in integrated circuits. As the thickness of silicon oxide dielectric reduces below 2 nm with continued downscaling, the leakage current because of tunnelling increases, leading to high power consumption and reduced device reliability. Hence, research concentrates on finding materials with high dielectric constant that can be easily integrated into a manufacturing process and show the desired properties as a thin film. Atomic layer deposition (ALD) is used practically to deposit high-k materials like HfO2, ZrO2, and Al2O3 as gate oxides. ALD is a technique for producing conformal layers of material with nanometer-scale thickness, used commercially in non-planar electronics and increasingly in other areas of science and technology. ALD is a type of chemical vapor deposition that depends on self-limiting surface chemistry. In ALD, gaseous precursors are allowed individually into the reactor chamber in alternating pulses. Between each pulse, inert gas is admitted to prevent gas phase reactions. This thesis provides a profound understanding of the ALD of oxides such as HfO2, showing how the chemistry affects the properties of the deposited film. Using multi-scale modelling of ALD, the kinetics of reactions at the growing surface is connected to experimental data. In this thesis, we use density functional theory (DFT) method to simulate more realistic models for the growth of HfO2 from Hf(N(CH3)2)4/H2O and HfCl4/H2O and for Al2O3 from Al(CH3)3/H2O.Three major breakthroughs are discovered. First, a new reaction pathway, ’multiple proton diffusion’, is proposed for the growth of HfO2 from Hf(N(CH3)2)4/H2O.1 As a second major breakthrough, a ’cooperative’ action between adsorbed precursors is shown to play an important role in ALD. By this we mean that previously-inert fragments can become reactive once sufficient molecules adsorb in their neighbourhood during either precursor pulse. As a third breakthrough, the ALD of HfO2 from Hf(N(CH3)2)4 and H2O is implemented for the first time into 3D on-lattice kinetic Monte-Carlo (KMC).2 In this integrated approach (DFT+KMC), retaining the accuracy of the atomistic model in the higher-scale model leads to remarkable breakthroughs in our understanding. The resulting atomistic model allows direct comparison with experimental techniques such as X-ray photoelectron spectroscopy and quartz crystal microbalance.

Plastid microsatellites for the study of genetic variability in the widespread Cephalanthera longifolia, C. damasonium and C. rubra (Neottieae, Orchidaceae), and cross-amplification in other Cephalanthera species

Plastid microsatellite loci developed for Cephalanthera longifolia were used to examine the level of genetic variation within and between populations of the three widespread Cephalanthera species (C. damasonium, C. longifolia and C. rubra). The most detailed sampling was in C. longifolia (42 localities from Ireland to China; 147 individuals). Eight haplotypes were detected. One was detected in the vast majority of individuals and occurred from Ireland to Iran. Three others were only found in Europe (Ireland to Italy, England to Italy and Austria to Croatia). Two were only found in the Middle East and two only in Asia. In C. damasonium, 21 individuals from 10 populations (England to Turkey) were sampled. Only one haplotype was detected. In C. rubra, 34 individuals from eight populations (England to Turkey) were sampled. Although it was not possible to amplify all loci for all samples of this species, nine haplotypes were detected. Short alleles for the trnS-trnG region found in two populations of C. rubra were characterized by sequencing and were caused by deletions of 26 and 30 base pairs. At this level of sampling, it appears that C. rubra shows the greatest genetic variability. Cephalanthera longifolia, C. rubra and C. damasonium have previously been characterized as outbreeding, outbreeding with facultative vegetative reproduction and inbreeding, respectively. Patterns of genetic variation here are discussed in the light of these reproductive system differences. The primers used in these three species of Cephalanthera were also demonstrated to amplify these loci in another five species (C. austiniae, C. calcarata, C. epipactoides, C. falcata and C. yunnanensis). Although it is sometimes treated as a synonym of C. damasonium, the single sample of C. yunnanensis from China had a markedly different haplotype from that found in C. damasonium. All three loci were successfully amplified in two achlorophyllous, myco-heterotrophic species, C. austinae and C. calcarata. © 2010 The Linnean Society of London.

The protective effect of heparin-binding haemagglutinin

info:eu-repo/semantics/nonPublished

Micro-mechanical parameterisations for continuum modelling of granular material using the discrete element method

The present work uses the discrete element method (DEM) to describe assemblies of particulate bulk materials. Working numerical descriptions of entire processes using this scheme are infeasible because of the very large number of elements (1012 or more in a moderately sized industrial silo). However it is possible to capture much of the essential bulk mechanics through selective DEM on important regions of an assembly, thereafter using the information in continuum numerical descriptions of particulate processes. The continuum numerical model uses population balances of the various components in bulk solid mixtures. It depends on constitutive relationships for the internal transfer, creation and/or destruction of components within the mixture. In this paper we show the means of generating such relationships for two important flow phenomena – segregation whereby particles differing in some important property (often size) separate into discrete phases, and degradation, whereby particles break into sub-elements, through impact on each other or shearing. We perform DEM simulations under a range of representative conditions, extracting the important parameters for the relevant transfer, creation and/or destruction of particles in certain classes within the assembly over time. Continuum predictions of segregation and degradation using this scheme are currently being successfully validated against bulk experimental data and are beginning to be used in schemes to improve the design and operation of bulk solids process plant.

Mathematical modelling of the behaviour of granular material in a computational fluid dynamics framework using micro-mechanical models

In this paper, a Computational Fluid Dynamics framework is presented for the modelling of key processes which involve granular material (i.e. segregation, degradation, caking). Appropriate physical models and sophisticated algorithms have been developed for the correct representation of the different material components in a granular mixture. The various processes, which arise from the micromechanical properties of the different mixture species can be obtained and parametrised in a DEM / experimental framework, thus enabling the continuum theory to correctly account for the micromechanical properties of a granular system. The present study establishes the link between the micromechanics and continuum theory and demonstrates the model capabilities in simulations of processes which are of great importance to the process engineering industry and involve granular materials in complex geometries.

Use of a coupled mechanical-acoustic computational model to identify failure mechanisms in paper production

In this paper, a couple mechanical-acoustic system of equations is solved to determine the relationship between emitted sound and damage mechanisims in paper under controlled stress conditions. The simple classical expression describing the frequency of a plucked string to its material properties is used to generate a numberical representation of the microscopic structue of the paper, and the resulting numerical model is then used to simulate the vibration of a range of simple fibre structures when undergoing two distinct types of damange mechanisms: (a)fibre/fibre bond failure, (b) fibre failure. The numercial results are analysed to determine whether there is any detectable systematic difference between the resulting acoustic emissions of the two damage processes. Fourier techniques are then used to compare th computeed results against experimental measurements. Distinct frequency components identifying each type of damage are shown to exist, and in this respect theory and experiments show good correspondece. Hence, it is shown, that althrough the mathematical model represents a grossly-simplified view of the complex structure of the paper, it nevertheless provides a good understanding of the underlying micro-mechanisms characterising its proeperties as a stress-resisting structure. Use of the model and acoompanying software will enable operators to identify approaching failure conditions in the continuous production of paper from emitted sound signals and take preventative action.

Experience of using a CFD code for estimating the noise generated by gusts along the sun-roof of a car

The problem to be examined here is the fluctuating pressure distribution along the open cavity of the sun-roof at the top of a car compartment due to gusts passing over the sun-roof. The aim of this test is to investigate the capability of a typical commercial CFD package, PHOENICS, in recognising pressure fluctuations occurring in an important automotive industrial problem. In particular to examine the accuracy of transporting pulsatory gusts traveling along the main flow through the use of finite volume methods with higher order schemes in the numercial solutins of the unsteady compressible Navier-Stokes equations. The Helmholtz equation is used to solve the sound distribution inside the car compartment, resulting from the externally induced fluctuations.

Insolvency: ordering a sale of the family home

Comments on the Chancery Division ruling in Nicholls v Lan on whether the interests of a bankrupt husband's creditors prevailed over those of the wife, despite her circumstances being exceptional within the meaning of the Insolvency Act 1986 s.335A on account of her suffering from chronic schizophrenia, where the wife was the joint owner of another property which could be realised to buy out the trustee in bankruptcy's half share in the equity of the matrimonial home.

Experiences during three generations of web based learning. Six years of web based communication

This paper tells the story of how a set of university lectures developed during the last six years. The idea is to show how (1) content, (2) communication and (3) assessment have evolved in steps which are named “generations of web learning”. The reader is offered a stepwise description of both didactic foundations of university lectures and practical implementation on a widely available web platform. The relative weight of directive elements has gradually decreased through the “three generations”, whereas characteristics of self-responsibility and self-guided learning have gained in importance. -Content was in early times presented and expected to be learned but in later phases expected to be constructed for examples of case studies. -Communication meant in early phases to deliver assignments to the lecturer but later on to form teams, exchange standpoints and review mutually. -Assessment initially consisted in marks invented and added up by the lecturer but was later enriched by peer review, mutual grading and voting procedures. How much “added value” can the web provide for teaching, training and learning? Six years of experience suggest: mainly insofar as new (collaborative and selfdirected) didactic scenarios are implemented! (DIPF/Orig.)