The sedimentology and diagenesis of the Pendleside limestone group in the Craven Basin of Northern England. Available in 2 volumes.

This thesis describes the stratigraphy, sedimentology and diagenesis of the Pendleside Limestone (Asbian age), a sequence of limestones, shales and dolostones in the Clitheroe area of N. W. England. Field study of 19 measured sections indicates that it was deposited in a rhythmically subsiding basin (Craven Basin) because of movements on the Mid-Craven Fault which was active in Dinantian times. The sequence is up to 190m thick and consists mostly of distal turbidite deposits which have been reworked at horizons when sediment accumulation built up to the wave base. The original depositional fabric and mineralogy of the Pendleside Limestone Group has been extensively modified by diagenetic processes including cementation, authi­genesis, dolomitization and silicification. These processes have been studied using a wide variety of laboratory techniques. The carbonate cements of the PendIeside Limestone consist predominantly of ferroan calcite and non-ferroan calcite with microdolomite incIusions. The former is probably a stable replacement of original-high-magnesian calcite. Cementation was accompanied by the formation of authigenic albite and quartz. Much of the upper part of the Pendleside Limestone has been extensively dolomitized and chertified. Several distinct zones of dolomitization are found which increase in thickness and intensity towards the top of the Pendleside Limestone Group. The dolostone horizons correspond to coarser-grained lithologies deposited during periods of shallow water sedimentation. The composition of the dolomites changes from ferroan dolomite in the lower part of the Group to non-ferroan dolomite in the upper part. The low strontium and sodium content of the dolostones in association with the other evidence suggests that the dolomitization was brought about in an open system by the mixing of marine and fresh water in phreatic lens which were established at periodic intervals. The dolomitization was closely associated with chertification although this was initiated by the dissolution of siliceous spicules which provided the necessary source of silica.

Langevin dynamics, large deviations and instantons for the quasi-geostrophic model and two-dimensional Euler equations

We investigate a class of simple models for Langevin dynamics of turbulent flows, including the one-layer quasi-geostrophic equation and the two-dimensional Euler equations. Starting from a path integral representation of the transition probability, we compute the most probable fluctuation paths from one attractor to any state within its basin of attraction. We prove that such fluctuation paths are the time reversed trajectories of the relaxation paths for a corresponding dual dynamics, which are also within the framework of quasi-geostrophic Langevin dynamics. Cases with or without detailed balance are studied. We discuss a specific example for which the stationary measure displays either a second order (continuous) or a first order (discontinuous) phase transition and a tricritical point. In situations where a first order phase transition is observed, the dynamics are bistable. Then, the transition paths between two coexisting attractors are instantons (fluctuation paths from an attractor to a saddle), which are related to the relaxation paths of the corresponding dual dynamics. For this example, we show how one can analytically determine the instantons and compute the transition probabilities for rare transitions between two attractors.

The influence of age and trait attributions on recruitment selection

The role of interpersonal attraction into the recruitment selection is gaining research attention. Early work in the domain of the influence of attraction in organisations suggested that men are given more resources, such as higher salaries and promotions. However, recent research has found women have an automatic in-group bias. It was suggested that female interviewers are more likely to hire another female. In contrast, male interviewers were found to be equally as likely to hire men as women. To resolve these two conflicting findings a behavioural experiment was set up looking at gender, attractiveness and recruitment selection. Forty participants, twenty male and twenty female, of varying ages (18-65) were recruited through age stratified sampling. Participants took on the role of manager of a medium sized company and were shown twenty photographs of faces previously rated for attractiveness. On initial viewing participants were asked to decide whether they would firstly hire the person and secondly give as many reasons for their decision. Findings from this research show that in all age groups male and female participants gave females (especially attractive females) more jobs, except in the case of the 18-21 year old females who gave attractive males more jobs. On examining the reasons behind the participant’s decisions, it was evident that if you appeared confident, friendly, youthful and attractive you were 46% more likely to receive the job. However, if you were perceived to be untrustworthy, lazy, arrogant and unintelligent you were 49% more likely not to receive the job. These findings shed light on the various processes that may underpin human resource decisions in an organisational setting.

Petrology of weathered lower lias clays

In weak argillaceous rocks the unweathered strength may be barely sufficient to meet civil engineering reguirements and any reductjon due to weathering will be critical. This study investigates the weathering of the Lower Lias clays with particular reference to their petrography and engineering properties. Investigations revealed the Midland Basin of deposition to contain reasonable thicknesses of clay, relatively uniform in nature with a well developed weathered zone, From the available exposures, the weathering zone of the Blockley Clay pit was selected and sampled for laboratory investigations of; Structure, Mineralogy and Chemistry and Engineering Properties. The nature and orientation of the fissures in the unweathered clay were analysed. A close relationship was found to exist between the major joint set and the ground surface, with stress release due to excavation being almost negligible. Thin sections of the clay, examined for structural data, suggested that there exist layers or areas that have been disturbed as a result of density differences. Shear planes were found in both the unweathered and weathered clay, in the latter case often associated with remoulding of the material. A direct measure of remoulding was obtained from the birefringence ratio. The fabric was examined in closer detail using the scanning electron microscope. Mineralogy, as revealed by X-ray and optical techniques indicated illite as the dominant clay mineral, with kaolinite subsidiary; quartz, calcite, pyrite, chlorite/vermiculite are present as accessory minerals. Weathering changes this relationship, calcite and pyrite being removed early in the process, with illite being degraded. The cementing action of calcite and iron oxides was investigated however, this was shown to be negligible. Quantitative measurements of both fixed (with minerals) and free (oxide coatings) iron were obtained by atomic absorption, with the Fe 3+/ Fe2+ ratio obtained by Mossbauer spectroscopy, Evidence indicates that free iron oxide coatings only become important as a result of weathering with the maximum concentration in the very highly weathered material. Engineering index properties and shear strength values were taken throughout the profile, Relationships between moisture content and strength, liquid limit and iron (Fe) were obtained and a correlation between the weathering zomes and the shear strength/depth curve has been established.

Bistable attractors in a model of convection-driven spherical dynamos

The range of existence and the properties of two essentially different chaotic attractors found in a model of nonlinear convection-driven dynamos in rotating spherical shells are investigated. A hysteretic transition between these attractors is established as a function of the rotation parameter t. The width of the basins of attraction is also estimated. © 2012 The Royal Swedish Academy of Sciences.

Magnetic drive system for a new centrifugal rotary blood pump

The purpose of this investigation was to design a novel magnetic drive and bearing system for a new centrifugal rotary blood pump (CRBP). The drive system consists of two components: (i) permanent magnets within the impeller of the CRBP; and (ii) the driving electromagnets. Orientation of the magnets varies from axial through to 60° included out-lean (conical configuration). Permanent magnets replace the electromagnet drive to allow easier characterization. The performance characteristics tested were the axial force of attraction between the stator and rotor at angles of rotational alignment, Ø, and the corresponding torque at those angles. The drive components were tested for various magnetic cone angles, ?. The test was repeated for three backing conditions: (i) non-backed; (ii) steel-cupped; and (iii) steel plate back-iron, performed on an Instron tensile testing machine. Experimental results were expanded upon through finite element and boundary element analysis (BEM). The force/torque characteristics were maximal for a 12-magnet configuration at 0° cone angle with steel-back iron (axial force = 60 N, torque = 0.375 Nm). BEM showed how introducing a cone angle increases the radial restoring force threefold while not compromising axial bearing force. Magnets in the drive system may be orientated not only to provide adequate coupling to drive the CRBP, but to provide significant axial and radial bearing forces capable of withstanding over 100 m/s2 shock excitation on the impeller. Although the 12 magnet 0° (?) configuration yielded the greatest force/torque characteristic, this was seen as potentially unattractive as this magnetic cone angle yielded poor radial restoring force characteristics.