5 resultados para the second law of thermodynamics

em Aston University Research Archive


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A typical liquid state NMR spectrum is composed of a number of discrete absorptions which can be readily interpreted to yield detailed information about the chemical environment of the nuclei found within the sample. The same cannot be said about the spectra of solid samples. For these the absorptions are typically broad, featureless and yield little information directly. This situation may be further exacerbated by the characteristically long T1 values of nuclei bound within a solid lattice which, consequently, require long inter-sequence delays that necessitate lengthy experiments. This work attempts to address both of these inherent problems. Classically, the resolution of the broad-line spectra of solids into discrete resonances has been achieved by imparting to the sample coherent rotation about specific axes in relation to the polarising magnetic field, as implemented in the magic-angle spinning (MAS) [1], dynamic angle spinning (DAS) [2] and double rotation (DOR) [3] NMR experiments. Recently, an alternative method, sonically induced narrowing of the NMR spectra of solids (SINNMR) [4], has been reported which yields the same well resolved solid-state spectra as the classic solid-state NMR experiments, but which achieves the resolution of the broad-line spectra through the promotion of incoherent motion in a suspension of solid particles. The first part of this work examines SINNMR and, in particular, concentrates on ultrasonically induced evaluation, a phenomenon which is thought to be essential to the incoherent averaging mechanism. The second part of this work extends the principle of incoherent motion, implicit in SINNMR, to a new genre of particulate systems, air fluidized beds, and examines the feasibility of such systems to provide well resolved solid state NMR spectra. Samples of trisodium phosphate dodecahydrate and of aluminium granules are examined using the new method with partially resolved spectra being reported in the case of the latter.

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The research work described in this thesis is concerned with the development of glassfibre reinforced plastics for structural uses in Civil Engineering construction. The first stage was primarily concerned with the design of GRP lamintes with structura1 properties and method of manufacture suitable for use with relatively large structural components. A cold setting, pressure moulding technique was developed which proved to be efficient in reducing the void content in the composite and minimising the exothermic effect due to curing. The effect of fibre content and fibre arrangement on strength and stiffness of the cornposite was studied and the maximum amount of' fibre content that could be reached by the adopted type of moulding technique was determined. The second stage of the project was concerned with the introduction of steel-wire "sheets" into the GRP cornposites, to take advantage of the high modulus of steel wire to improve the GRP stiffness and to reduce deformation. The experimental observations agreed reasonably well with theoretical predictions in both first and second stages of the work. The third stage was concerned with studying the stability of GRP flat rectangular plates subjected to uniaxial compression or pure shear, to simulate compression flanges or shear webs respectively. The investigation was concentrated on the effect of fibre arrangement in the plate on buckling load. The effect of the introduction of steel-wire sheets on the plate stability in compression was also investigated. The boundary conditions were chosen to be close to those usually assumed in built-up box-sections for both compression flanges and webs. The orthotropic plate and the mid-plane symmetric were used successfully in predicting the buckling load theoretically. In determining the buckling load experimentally, two methods were used. The Southwell plot method and electrical strain gauge method. The latter proved to be more reliable in predicting the buckling load than the former, especially for plates under uniaxial compression. Sample design charts for GRP plates that yield and buckle simultaneously under compression are also presented in the thesis. The final stage of the work dealt with the design and test of GRP beams. The investigation began by finding the optimum cross-section for a GRP beam. The cross-section which was developed was a thin walled corrugated section which showed higher stiffness than other cross-sections for the same cross-sectional area (i.e. box, I, and rectangular sections). A cold setting, hand layings technique was used in manufacturing these beams wbich were of nine types depending on the type of glass reinforcement employed and the arrangement of layers in the beam. The simple bending theory was used in the beam design and proved to be satisfactory in predicting the stresses and deflections. A factor of safety of 4 was chosen for design purposes and considered to be suitable for long term use under static load. Because of its relatively low modulus, GRP beams allowable deflection was limited to 1/120th of the span which was found to be adequate for design purposes. A general discussion of the behaviour of GRP composites and their place relative to the more conventional structural material was also presented in the thesis.

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This study aims to investigate the pyrolysis behaviour of metal-contaminated wood and the combustion properties of char derived from wood pyrolysis. Seven metals (Na, Mg, Ca, Zn, Cd, Pb and Fe(III)) were introduced to willow in cation form by ion-exchange and the thermal behaviour of demineralised samples and samples with additional ash were also investigated. The results show that the char yield increased from 21% to 24-28% and levoglucosan yield in vapour phase decreased from 88% to 62-29% after the addition of inorganic compounds, even though the metal binding capacity of wood varied from one metal ion to another. While char yield seems to be effected mainly by the concentration of the metal ions, levoglucosan yield was more dependent on the ionic species especially when sodium ions were present. When combustion experiments were carried out with char made of the metal enriched wood, two consecutive steps were observed, both effected by the presence of inorganic compounds. The first step was identified as the release and combustion of volatiles, while the second peak of the burning profile is the actual combustion of the fixed carbon. The burnout temperatures, estimated ignition indices and the conversion indicate that the type and not the amount of metal ions were the determining factors during the second step of combustion. © 2012 Published by Elsevier B.V.

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Introduction For a significant period of time (the late 1950s--1980s), a lack of capital freedom was a major obstacle to the progress of the internal market project. The free movements of goods, persons and services were achieved, and developed, primarily through the case law of the Court of Justice of the European Union (CJEU). On the other hand, the Court played a (self-imposed) limited role in the development of the free movement of capital. It was through a progressive series of legislation that the freedom was finally achieved. John Usher has noted that the consequence of this is that ‘free movement of capital thus became the only Treaty “freedom” to be achieved in the manner envisaged in the Treaty’. For this reason, the relationship of the Court and legislature in this area is of particular importance in the broader context of the internal market. The rest of this chapter is split into four sections and will attempt to describe (and account for) the differing relationships between the legislature and the judiciary during the different stages of capital liberalisation. Section 2 will deal with the situation under the original Treaty of Rome. Section 3 will examine a single legislative intervention: Directive 88/361. It was this intervention that contained the obligation for Member States to fully liberalise capital movements. It is therefore the most important contribution to the completion of the internal market in the capital sphere. An examination will be made of whether the interpretation of the Directive demonstrates a changed (or changing attitude) of the Court towards the EU legislature. Section 4 will examine the changes brought about by the Treaty on European Union in 1993. It was at Maastricht that the Member States finally introduced into the Treaty framework an absolute obligation to liberalise capital movements. Finally, Section 5 will consider the Treaty of Lisbon and the possibility of future interventions by the legislature. By looking at the patterns that run through the different parts, this chapter will attempt to engage with the question of whether the approaches were products of their historical context, or whether they can be applied to other areas within the capital movement sphere.

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This doctoral study aims to understand how experiences of critical illness or bereavement affect the way managers view and approach their work and their relationships at work. This is an interpretative phenomenological study examining the subjective meanings of personal experience and is underpinned by biographic narratives from four participants and interviews with their nominated workplace witnesses (i.e. colleagues who worked alongside the individual at the time of their trauma). As a consequence of the findings that have emerged across this study, three contributions to theory are presented. All four participants described their traumas as a professional growth experience for themselves as managers, which resulted in self-reported and observed behaviour change at work. Consequently, the first area of theoretical contribution is a suggested extension to the post-traumatic growth (PTG) framework (Calhoun & Tedeschi, 2006) with the addition of a new behavioural dimension called ‘managerial growth’, when applied to the context of ‘ordinary’ organizations. The second area of theoretical contribution arose through the reflexive process that was created during data collection where participants and their witnesses remembered episodes of compassion interaction at work. The second area of contribution thus seeks to extend the existing model of compassion at work (Dutton, Worline, Frost and Lilius, 2006), by conceptualising compassion as a dyadic process between a compassion ‘giver’ and a compassion ‘receiver’ in which the compassion receiver ‘trusts or ‘mistrusts’; ‘discloses’ or ‘withholds’; ‘connects’ or ‘disconnects’ with the compassion giver. The third area of contribution is a new conceptualisation of reflexivity, ‘three-dimensional reflexivity’ (3DR) (Armstrong, Butler and Shaw, 2013). 3DR brings together three of the elements that have been missing from critically reflexive management research; by working with multiple variants of reflexivity in the same study; surfacing different reflexive voices to guard against the researcher’s (potentially) solipsistic own; and remaining sensitive to the concept of reflexive time. In doing so, 3DR not only provides a deeper understanding of individual lived experience; it is also a vehicle in which self-insight is gained. Furthermore, by engaging in its practice, those involved in this study have developed both personally and professionally as a result.