Simulation modelling and strategic change : creating the sustainable enterprise

Peer reviewedPublisher PD

How was it for you? A cross-disciplinary study of ‘troublesome knowledge’ as identified by undergraduate students and lecturers in Geography, Medical Science and Psychology

We carried out a small scale pilot study to determine whether participants would spontaneously identify Threshold Concepts (TC’s) and/or troublesome knowledge during open questioning on the characteristics of their disciplines. Students and lecturers reflected upon both easy and difficult aspects of their studies or teaching practice in either group discussions or one-to-one interviews. We compared students and staff observations both within and between the disciplines we examined (Geography, Medical Sciences and Psychology undergraduate degrees). Our intention was to provide specific examples of TC’s within our three disciplines to inform further discussion of embedding the enhancement theme both in our practice and in the learning experiences of our students. Our working hypothesis was that if TC’s exerted an influence on the teaching and learning experience either negatively or otherwise, then we would find ample evidence supplied in our interviews. What we found was that overwhelmingly our interviewees focussed on generic skills-based aspects of teaching and learning. Only three potential content-specific TC’s were offered spontaneously by students and these were all from the discipline of geography

Prediction of pressure drop in multiphase horizontal pipe flow

Empirical correlations were tested against reliable two phase pipe flow data for the prediction of pressure drop. Correlations are recommended for the prediction with stratified and annular type flows. When these correlations were adapted to three phase gaswater-oil pipe flow in general they predicted for intermittent slug type flows. Momentum balance models could not be successfully adapted to the prediction of pipe three phase pressure drop

An Object-Oriented System for Engineering Polymer Information

Issues arising from the development of a computer-based information system for engineering polymer data have been explored. The system was designed with the aim of providing a user-independent representation of engineering polymers that would organise the data pertaining to them and be amenable to extension and evolution to allow for new materials and new properties. A classification of engineering polymer materials was developed to provide the structure for the representation, and an existing computer information system was modified in order to accommodate it. The classification was designed to create and order classes of similar materials to enable easy access to their information. Criteria for grouping material grades into families and families into a hierarchy were assessed. Existing polymer classifications were analysed; several alternative approaches to the factoring process are described. The final taxonomy was implemented within the object-oriented information system POISE, written in the language Smalltalk 80TM. Inherent in the system is a facility to support browsing of general class information. Other tools developed during the course of the project allow the addition and positioning of new classes, grades, properties and data and searching for grades by property value or name. It was shown that a classification based on criteria of similar chemical structure is a prerequisite for extensibility. Also demonstrated was that no such classification will consistently group together grades that are similar in respect of all of their physical and engineering property data for the uses of engineering designers. A detailed analysis of the properties used to describe grades of engineering polymer gave an insight into the above dichotomy. To accommodate the resulting conflict, the polymer information system was enhanced to incorporate an orthogonal factoring at the grade level in addition to that already created by the final classification based on chemical families

Meltwater controls on ice-marginal sedimentation

This thesis explores the influence that meltwater exerts on styles of ice-marginal sedimentation, using past and present examples from Iceland. The study glaciers display marked contrasts in form, size and composition of moraines which are unlikely to reflect differences in rates of subglacial erosion. This is because the study glaciers occupy a similar climate, show similar relief, sit above similar bedrock, and are inferred to flow at similar speeds. The observed variation in moraine properties must reflect some other process which intervenes to modify sediment transport relationships prior to the arrival of debris at the ice edge. I argue that this key factor which controls sediment transport - and, as a result, the potential to form moraines - is the behaviour of subglacial meltwater flows.Studies of the sediment load of its outlet river show that Solheimajokull is a highly erosive glacier, yet the quantity of debris carried by the ice is extremely small. Consequently, presentday moraine formation is extremely limited. This can best be explained as the product of an aggressive subglacial drainage network which captures and evacuates the bulk of debris generated by subglacial erosion. This state of high efficiency subglacial flushing is likely to dominate the sediment budget of many temperate glaciers.Whereas the present-day margin of Solheimajokull is debris-poor, the present-day margins of Gfgjokull and Steinholtsjokull are debris-rich. This debris consists of two major populations: 1) rounded clasts set in a sorted coarse sand and gravel matrix, derived from a series of englacial debris bands, and, 2) sub-angular clasts in a poorly-sorted matrix, derived from unusually thick sequences of basal ice. Overdeepened basins lie beneath the termini of both Gfgjokull and Steinholtsjokull. It seems that changes in water flow in this zone - rising water pressures associated with water flow upslope cause drainage to take up an englacial route - explain both the debris bands and the basal ice. The debris bands form as sediment-laden englacial channels close-up; simultaneously, the paucity of water at the glacier bed, in conjunction with strongly compressive ice flow, favours widespread preservation of basal ice. I extend Hooke's model of the ice-fall/overdeepening as a process system favourable to subglacial erosion to argue that it also creates conditions favourable to debris retention in ice, and so rapid accumulation of ice-marginal moraines.The idea that contrasts in the behaviour of drainage account for contrasts in moraine development adds depth to studies of the glacial geologic record, and its interpretation in termsThis thesis was written with the specific intent of linking process and form in such a way as to provide a meaningful explanation of moraine development. Different moraine forms are the emergent product of the multitude of process interactions which make up a complex causal network dispersed in time and space. The key factor which regulates this is the behaviour of meltwater. Glacier drainage systems provide the crucial contextual element which links the basic level of process (reductionist analysis) to the level of surface appearance (observations of moraine form). Drainage systems carry genuine causal powers which cannot be broken down into smaller process systems without the loss of explanatory power. This ties in with realist traditions of science, and recent ideas associated with complexity theory

Enhanced drag in pipe turbulent flow by an aqueous electrolyte: an electroviscous effect

Drag enhancement is reported for turbulent pipe flow of aqueous electrolyte solutions. No electroviscous effect was obtained with laminar flow. Nor was any unusual pressure drop observed for laminar or turbulent flow of non-electrolyte aqueous solutions such as sugar. An electroviscous theory was advanced that predicted the drag enhancement for a 1/1 electrolyte solution. The theory depended on consideration of Debye length