De Montfort University e-theses

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Open Access
The development of kinetic sculpture by the utilization of solar energy.
(De Montfort University, 1978) Stonyer, Andrew Allan
Open Access
Fundamental study of adhesion problems involving polyethylene and other polymers
(De Montfort University, 1979) Konieczko, Michael Boguslaw
Open Access
Iconic conductors for solid state battery systems
(De Montfort University, 1979) Hackwood, Susan
In this project, it has been demonstrated that cuprous iodide -sulph.onium iodide double salts, similar to the silver iodide systems previously studied by other workers, are suitable for use in ambient temperature batteries for low current applications. A number of potential solid electrolytes, in which the mobile species is calcium, have also been investigated, and areas for further work have been defined. The relavent section of the thesis is confidential as patent proceedings are possible. The project has involved not only a search for new electrolytes, but also the development of a search strategy. In view of the limitations of direct conductivity measurements on compacted materials, arising from electrical contact problems, considerable use has been made of indirect methods. A critical review of standard electrochemical techniques, often adapted from aqueous methods, has been carried out. This has highlighted shortcomings in the measurements of such para.meters as electronic conductivity, where the self-discharge rate, a pare.meter used by battery technologists, has been found more meaningful than the results obtained from Wagners blocking electrode technique. X-ray diffraction (XRD), and differential thermal analysis (DTA) have been used to disprove the common assertion that the effect of addition of organic dopant materials to silver iodide ha.s the effect of stabilizing the high temperature high conductivity alpha phase. CuI based electrolytes have been found to differ significantly from the AgI analogues in several respects. No simple structural criterion, such as the Group Weighting Coefficient for AgI systems, could be found to predict the effect of addition of organic sulphonium iodide dopants. Battery cells based on Cul did not give the expected thermodynamic open circuit voltage (OCV), and three electrode measurements failed to elucidate this anomaly. The possible involvement of the cupric ion was explored in several ways, including the first application of Auger electron spectroscopy for this type of electrolyte system. The battery discharge characteristics showed a fairly low efficiency, but indirect evidence including the inadvertent involvement of a novel solid state aurous system, pointed to the majority of the anode material being unavailable for reaction.
Open Access
The ecology of the Chironomidae (Diptera) in a new eutrophic reservoir
(De Montfort University, 1980) Brown, Andrew Edward
The successional changes in a new. lowland reservoir in Leicestershire, England, were investigated, with particular referece to larvae of the Chironomidae. During the first four years major changes in water chemistry were the result of the different sources of water used to fill the reservoir and the release of nutrients from the inundated terrestrial vegetation. Phytoplankton populations showed erratic changes in species composition and standing crop during the first year of filling. Seasonal fluctuations, similar to those observed at other eutrophic reservoirs, occurred in subsequent years. Chironomid species composition and temporal and spatial variation in the larval populations were investigated. Orth6cladiinae larvae were particularly abundant in mats of algae in shallow water in the second year after filling commenced. This was probably the result of a stable water level, warm weather conditions and high nutrient concentrations. In the third year Chironomus p lumosus and Polypedi tum nubeculosum larvae were numerically do~nant. Populations of these spec~es declined the following year and Tanytarsus species predominated. Temporal changes of the fauna were lnfluenced by climate and the filling regime of the reservoir. Chironamid larvae did not indicate any marked differences in water quali ty be tween the two arms of the reservoir. Populations were generally found to be contagious ly dis tributed. Chironomids in rainbow and brown trout diets were investigated during the first two fishing seasons. The species composition of larvae and pupae in the diets suggested different feeding zones for the two trout species. The behaviour of chironomid larvae and not their numerical abundance determines their occurrence in the diets. The results from this study are discussed in relation to management of the reservoir. Due to the importance of chironomids in trout diet it may be beneficial to base stocking policy on a knowledge of the seasonal population fluctuations of the chironomids.
Open Access
INVESTIGATION OF A DIESEL GAS TURBINE
(De Montfort University, 1980-06) Parkin, Robert
The turbocharging of automotive sized two-stroke engines presents a problem to the designer due to the large range of loads and speeds met in service. A mechanically driven blower is usually required to provide a positive pressure drop across the engine at all times, thus providing adequate air for scavenging. The aim of this investigation is to consider a. combination of the two-stroke cycle engine, turbocharger and auxiliary combustion chamber as a prime mover system with a satisfactory torque characteristic and control system. The auxiliary combustion chamber is used for independent control of the turbocharger. To this end various component combinations are described and assessed. Turbochargers of different builds and frame sizes havebeen examined to assess the effects of turbocharger matching. Computerised processing for data acquisition and control has been used. Theoretical work, progressing simultaneously with the experimental programme, has permitted the development of simple computer programs to predict system performance to a good degree of accuracy. The programs are detailed in the appendix. Experimental results have been presented graphically and compared with those predicted by the computer programs. The work has been extended, by computer techni~ues, to investigate the effects of charge cooling, heat exchange, and torque 'tailoring' by the control of engine boost levels. The Diesel Gas Turbine is shown to provide a feasible prime mover system. Significant improvements of power output and torque characteristic have been achieved within constraints of thermal and mechanical loading. The system incurs penalties in specific fuel consumption at low speeds but these are offset, to some extent, by improvements at high speed. The improved torque characteristics; would permit the use of a simpler transmission system, together with the removal of the scavenge blower.
Open Access
Thermal stratification in solar storage tanks
(De Montfort University, 1981) Eldessouky, Elsayedabd Elha
The purpose of the work was to investigate the thermal stratification in solar storage containers. Three domestic thermally stratified hot water storage containers were designed with the main object of improving and stabilizing thermal stratification of the stored water as a means of improving the overall efficiency of solar water heating systems. Testing of the three storage containers was carried out under similar conditions and the results showedthat TYPEI storage container behaves as a three-segment stratified system, TYPEII storage container behaves as a two-segment stratified system with a thermocline occupying approximately half of the height of the storage container, and TYPEIII storage container behaves as a two-segment stratified system with a thermocline occupying two thirds of the height of the storage container. It was found that TYPEI storage container, with a LID equal to 3/1, gave the best results in terms of heat collected, and also had the maximum stratification which is the main goal of this study. The effect of each of three flow rates (0.01 kg/Sm2 , 0.015 kg/sm2 , 0.02 kg/sm2 ) on stratification was studied and it was found that the flow rate of 0.01 kg/Sm2 of collector area gave the better result. A low-cost simulator for studying the performance of solar energy storage containers was designed. The design was based on a relatively inexpensive micro-computer linking into a mains power regulator with an 8-bit digital control system. Meteorological data was used to compute radiation income on any inclined plane and the output to the power regulator is controlled by the computed instantaneJus rate of energy gain from the collector system undergoing simulation.A comparison has been made between some of the experimental and theoretical results for mE I storage container. The theoretical prediction was based on two mathematical IOOdels of Duffie and 2 44 Beckman , and Close • A computer system model has been developed to assist in the design of a solar water heating system.
Open Access
Studies on the fluidised bed granulation process.
(De Montfort University, 1981) Banks, Michael
This study is an evaluation of the process of fluidised bed granulation with the objectives of elucidating the mechanism of granule formation and identifying the fundamental parameters affecting granule quality thereby enabling the true benefits of the process to be realised. Initially the effect of seven process variables upon granule quality was quantified using a factorially designed experiment. During granule assessment the torque generated by a paddle revolving in a granule mass was shown to be a useful measure of granule quality. The variables found to exert a significant effect upon granule quality were those which affected the wetting of the powder mix and rate of evaporation during granulation. A closer examination of those factors influencing bed wettability was indicated. This was achieved by studying the spray characteristics and droplet size of the atomised granulating solution, and investigating powder bed hydrophobicity. Spray characteristics of the atomised granulating solution were measured using a Malvern ST 1800 Particle and Droplet Size Analyser. A direct correlation was shown between droplet size and granule siize. Coarse, free flowing granules were obtained from sprays with large droplets, wide droplet size distributions and high granulating solution addition rates. A linear relationship was shown between the cosine of the solid/liquid contact angle and granule size. The addition of surfactant {sodium lauryl sulphate} to a model hydrophobic system was shown to improve granulation. This was related to improved powder/liquid affinity. Surfactant dissolved in the granulating solution gave slightly coarser granules with improved flow properties than when added directly to the powder mix. This was attributed to changes in spray characteristics and improved wetting by the atomised granulating solution. The growth mechanism and granule structure were subsequently investigated in a number of model powder systems using sieve analysis, scanning electron microscopy, a specially developed fluorescent technique to monitor binder distribution and a solvent extraction procedure which left a network of binder. Close examination of the data enabled a growth mechanism to be proposed for lactose and modifications to this were discussed for the other materials investigated. Thus, based on the changes occurring in the microenvironment during powder particle/droplet collision, those factors which significantly influence granule formation have been identified. These were principally the physico-chemical properties of the starting materials and the properties of the granulating droplets.
Open Access
Bioavailability studies on orally administered, oily suspensions of drugs.
(De Montfort University, 1981) Alhammami, Omran Moosa Omran.
Open Access
A study of the problems of man-computer dialogues for naive users
(De Montfort University, 1981-01) Maguire, Martin
The success of an interactive computing facility will depend, to a large extent, upon the effectiveness of the man-computer dialogue which it supports. Comparatively little work has been directed towards the design of effective dialogues for situations in which the 'man' is a 'naive' user i.e. a person without training or experience of computer procedures. Thus the aim of this project has been to produce a series of specialised guidelines for designers of dialogues for naive users. An examination of the literature reveals that published dialogue guidelines tend to be of a general purpose nature and therefore cannot be applied directly to specific situations. Furthermore, as each set of recommendations is based upon a limited range of experience, authors opinions appear to contradict or be in need of further qualification. At a practical level, a survey of computer games, intended to be self-explanatory and therefore suitable for naive users, bears out the widely held feeling that the dialogue interface is often a poorly considered aspect of interactive program writing. Pilot studies highlight the need for experimental work into man-computer dialogues to be carried out under conditions conforming as closely as possible to a 'real world' environment. The main study focuses upon the general public as users of a local information system developed and installed in Leicester's Information Bureau. Monitoring the public's usage of and reactions to the system has enabled a series of dialogue guidelines for public information systems to be produced. A review of the literature provides supplementary recommendations. The influence of dialogue recommendations on the software writing community is considered. Less than half of a sample of application programmers are found to refer to material of this kind. Follow up interviews indicate that the concept of a dialogue guideline is too narrow and should be broadened to cover all types of dialogue design information. This would render it more applicable to differing design situations. For designers who do not refer to published material, it is suggested that .sound principles can be communicated via trained experts and the use of library subroutines supporting dialogue creation. An example is considered of a routine to process textual inputs. A number of paths for future research are described concerning the development of experimental methodology suitable for testing man-computer dialogues, an evaluation of the proposed strategy for communicating dialogue design principles and the application of new input/output techniques to public information systems. It is also suggested that the likely social consequences of computerised information facilities should be determined.
Open Access
The effects of changes in engine geometry on the breathing and combustion in a spark ignition engine
(De Montfort University, 1982) Newlyn, Hugh Anthony
The effects of changes in engine geometry on the breathing and combustion processes in a spark ignition engine have been investigated. It has been shown that a survey of engine geometry can readily illustrate design limitations in three areas : Fluid dynamic, Mechanical and Thermodynamic, and so reduce the extent of investigation available to the designer. The induction performance has been analysed mathematically and comparisons made with experimental work. The results indicate that an assessment of the effect of changes of geometry can be made using empirical relationships without complex mathematics. An attempt has been made to relate the turbulent to laminar flame speed ratio to the engine's physical parameters. These results compare well with previously published work by other workers.
Open Access
The acoustic properties of textile fabrics.
(De Montfort University, 1982) Atwal, Mahabir Singh
Open Access
The development of a method for generating patterns for garments that conform to the shape of the human body.
(De Montfort University, 1982) Efrat, S.
Open Access
An interactive raster graphics system and language for artists and designers.
(De Montfort University, 1982) Scrivener, Stephen A. R.
Open Access
The resolution of ambiguities and the correction of errors in the automatic transcription of palantype.
(De Montfort University, 1982) Booth, Alexander W.
Open Access
Control of dimensions and quality of weft knitted fabrics.
(De Montfort University, 1982) Duke, Ronald Arthur
Open Access
An investigation of electron tunnelling and conduction in Langmuir films
(De Montfort University, 1982-09) Ginnai, Tariq Mahmood
Langmuir films offer the possibility of obtaining unifo:r:m, wellordered, insulating structures of defined and controllable thickness. In this thesis, techniques for the fabrication of these films and the nature of the conduction process in single and multi-layer films of stearic acid/stearate sandwiched between metal electrodes (HIM devices) are discussed. A sophisticated film fabrication system has been designed and implemented and methods necessary for obtaining films of high integrity established. Structural characterisation studies using various techniques demonstrate that the resultant films are unifo:r:m, of predictable composition and substantially free of defects. In single layer MIM devices, detailed observations of the voltage and temperature dependence of the current suggest that the predominant conduction mechanism is direct electron tunnelling between the metal electrodes. This has been confirmed with the aid of additional experiments, including consideration of the role of the oxide film(s) invariably present in the canpleted device and investigation of the inelastic component of the tunnel current. It is argued that the latter provides unequivocal evidence that a significant proportion of all conduction is by electron tunnelling. In multilayer (3-5 layers) MIM devices, the importance of Schottky emission as a mechanism for conduction has been confirmed through a careful examination of the current-voltage relationship and on the basis of the temperature dependence of the current at fixed voltage. Finally, the techniques of Auger and X-ray photoelectron spectroscopy have been employed to provide further insight into the nature of film adhesion and composition. These observations, where possible, have been correlated with the results of electrical measurements.
Open Access
Patterns of organisation in constructed art
(De Montfort University, 1983) Tebby, S. J.
Open Access
Calorimetric and related studies of disorder in solid electrolyte and similar materials.
(De Montfort University, 1984) Hall, Peter Gerald
Open Access
Computer aided studies of the tablet compression process.
(De Montfort University, 1984) Celik, Metin
The compactional behaviour of a range of materials has been investigated by using an instrumented, 25.4 mm diameter punch and die set in conjunction with a Mayes Hydraulic Testing Machine. A CBM microcomputer with a multi-channel 3D-ADC was employed to monitor applied force of up to 45kN, the radially transmitted pressure to the die wall, die base reaction and punch displacement. Avicel and Sta-Rx compacts exhibited greater contact time, energy absorbtion and higher rate of radial pressure transmission to the die wall than was shown by Emdex, Emcompress and Paracetamol DC. It was deduced from the form of Heckel plots that time dependent bases Avicel and Sta-Rx underwent further densification when held under a constant stress. Densification of the mate~ials were usually greater if a slower speed of compression was used. Time dependent strain movements of the formed compacts held under a constant stress within the die have been investigated. The elastic and viscoelastic recoveries observed on load release have also been studied. The effects of various parameters on these movements and the feasibilty of using an elastic recovery index to predict the quality of a material are discussed. Avicel and Sta-Rx exhibited an extended plastic flow when held under a constant stress. Poorly compressible materials such as magnesium stearate and paracetamol exhibited the least strain movements and the greatest elastic expansion. It was found that the elastic recovery indices of the compressible materials were always lower than those of poorly compressible powders. Viscoelastic behaviour of the compacts after ejection has been studied following the changes in depth of penetration of an indenter over a long period into the surface of the compacts. Creep compliance curves obtained from the above two techniques have been compared. Both tests enable important viscoelastic parameters of the materials to be determined. Viscoelastic properties deduced from indentation tests were brought1y similar to those obtained by compression within the die. Throughout the work all data were recorded, processed and presented using a microcomputer and disk storage. Compressional criteria which are defined in the thesis have been found useful in evaluating some commercial granulates.
Open Access
Formation of methylmercury in the environment.
(De Montfort University, 1984) Moreton, Peter Allan