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This thesis describes an investigation into the vibration serviceability of long-span and slender in-situ concrete floors, which are typically post-tensioned. The motivation for the research is the present trend towards increased slenderness of post-tensioned floors supporting open-plan high- quality offices where vibration serviceability may easily become the governing design criterion. The vibration serviceability issue in post-tensioned floors is now also recognised by the UK Concrete Society which proposed, for the first time, guidelines for performing a vibration serviceability check when designing office floors. The guidelines were published in Concrete Society Technical Report 43 (CSTR43) in 1994 and its publication prompted the initialisation of this research project. There were two reasons for this. Firstly, problems were reported with the reliability and practical application of these guidelines, and, secondly, the guidelines were not experimentally verified which is unusual for any design provision related to vibration serviceability. In order to improve understanding of the dynamic performance of a rather specific group of office floors which are long-span and made of cast in-situ concrete, a combined experimental and analytical approach has been adopted. A state-of-the-art facility comprising hardware and software suitable for field modal testing and dynamic response measurements of prototype floor structures was commissioned as a part of this research. The facility is built up around the instrumented sledge hammer, which served as the main excitation source in modal testing, and multi-degree-of-freedom vibration parameter estimation procedures utilising measured floor frequency response functions. The main testing programme consisted of modal testing of four prototype floor structures of varying complexity weighing between 13 and 1000 tonnes. All four slab structures were slender and made of in-situ concrete. These tests were complemented by measurements of the floors' acceleration responses to a single person walking excitation tuned to create as large as realistically possible responses. The modal testing experimental data (measured natural frequencies, mode shapes and modal damping ratios) were used to validate numerical finite element (FE) models representing each floor structure. To do this, advanced FE model correlation and manual updating procedures were employed. Results of these exercises highlighted a number of important issues related to the dynamic behaviour of the concrete floors investigated. Firstly, the bending stiffness of in-situ concrete columns and walls contributed significantly to overall floor bending stiffness and must be considered. Secondly, higher modes of vibration which are close to the fundamental frequency appear in concrete floors, and should not be neglected as they can be easily excited by walking leading to dynamic responses greater than those associated with the fundamental mode. Thirdly, the width of band beams contributes significantly to the lateral stiffness of post-tensioned floors, which, in turn, may be very beneficial for their vibration serviceability. The validated numerical FE models were then used to check the performance of three representative walking excitation models available in the literature. It was shown that, in general, all three models overestimated the measured response to the third harmonic of the walking excitation, which is particularly important for low-frequency office floors. Only one of the models did so in a way which is not overly conservative. This model is recommended for use in vibration serviceability assessment of post-tensioned floors. Finally, gross oversimplification of these important issues is identified as the principal reason for the failure of the current CSTR43 vibration serviceability guidelines to predict reliably vibration response of a wide range of post-tensioned in-situ cast concrete floors.

This thesis explores certain aspects of the structure of lexical semantics and its interaction with pragmatic processes of utterance comprehension, using as a case-study a sample of the English modal verbs. Contrary to previous polysemy-based accounts, I propose and defend a unitary semantic account of the English modals, and I give a relevance-theoretic explanation of the construction of their admissible (mainly, root and epistemic) contextual interpretations. Departing from previous accounts of modality, I propose a link between epistemic modality and metarepresentation, and treat the emergence of epistemic modal markers as a result of the development of the human theory of mind. In support of my central contention that the English modals are semantically univocal, I reanalyse a range of arguments employed by previous polysemy-based approaches. These arguments involve the distributional properties of the modals, their relationship to truth-conditional content, the status of so-called speech-act modality, and the historical development of epistemic meanings: it turns out that none of these domains can offer reasons to abandon the univocal semantic analysis of the English modals. Furthermore, I argue that the priority of root over epistemic meanings in language acquisition is predicted by the link between epistemic modality and metarepresentation. Finally, data from a cognitive disorder (autism) are considered in the light of the metarepresentation hypothesis about epistemic modality. The discussion of modality has a number of implications for the concept of polysemy. I suggest that, despite its widespread use in current lexical semantics, polysemy is not a natural class, and use the example of the Cognitive Linguistics to illustrate that polysemy presupposes some questionable assumptions about the structure of lexical concepts. I propose a division of labour between ambiguity, semantic underdeterminacy, and a narrowed version of polysemy, and present its ramifications for the psychology of word meaning. In the final chapter, I extend the proposed framework for modality to the analysis of generic sentences, thereby capturing certain similarities between genericity and modality.

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Previous work on modal analysis of mooring lines has been performed from different theoretical formulations. Most studies have focused on mooring lines of a single homogeneous material, and the effect of added mass and damping produced by the water has not been examined deeply. The variational formulation approach, employed in this research to perform a modal analysis, has been useful to study the behavior of several realistic mooring lines. The cases presented are composed from segments of materials with different mechanical characteristics, more similar to those in current offshore projects. In the newly proposed formulation, damping produced by transverse motion of the mooring line through the surrounding water has been added to the modal analysis. The modal analysis formulation applied in this work has been verified with calculations from commercial software and the results are sufficiently accurate to understand the global behavior of the dynamics of mooring lines with the damping produced by the sea water. Inclusion of linearized drag damping in the modal analysis showed that the modal periods of the mooring systems studied depend on the amplitude of the transverse motion of the mooring line. When more amplitude in the motion is expected more damping is obtained. Two realistic designs of mooring lines were compared: one made up with a main insert of steel rope, called “Steel System”, and one composed by a main insert of polyester, named “Polyester System”. Comparing the natural periods of both systems, the Steel System appears to be safer because its fundamental natural period is more distant from the wave excitation periods produced by storms. The same happens considering the wave excitation periods produced by prevailing seas. In this case the natural periods of the Polyester System are nearer to the wave excitation periods causing fatigue loads. The transverse mode shapes for lateral motions of the mooring lines are observed to be continuous and smooth across material transitions, such as transitions between chain and wire rope and transitions between chain and polyester rope. This behavior is not always observed in the tangential mode shapes for the Polyester System where significant differences in dynamic tension seem to be present in the specific cases studied.

A study of vibrations and sound radiation in upright and grand pianos has been made to determine whether the piano may be improved by altering the materials of the component parts which are traditionally fabricated in timber. Modal analysis and sound level measurements of an upright piano has shown that the radiation from the case is at least 20 dB lower than the radiation from the soundboard, and therefore the case is not a significant determinant of piano tone. A method was developed for separating piano sound and vibrations into broadband and tonal components and used to compare the performance of upright and grand pianos. Using this method it was found that the broadband vibration level was twice as high in the uprights as in the grands. A finite element model of an upright piano was developed and used to demonstrate that replacing the keybed with a higher impedance material than conventionally used would reduce the key vibration level, and hence bring the uprights closer in performance to grand pianos, and improve the 'feel' of the instrument for the player. The keybed of one of a pair of identical pianos was replaced with high density fibreboard, and subsequent objective measurements showed that the broadband component of key vibrations was reduced by 3.2 dB while the radiated sound was unchanged. A controlled subjective comparison between the modified and unmodified pianos undertaken by experienced players showed that a statistically significant number preferred the modified piano, and that the upright piano had been improved. / Acoustics Research Centre, Department of Mechanical Engineering, Foundation for Research Science and Technology, Fletcher Wood Panels.

A study of vibrations and sound radiation in upright and grand pianos has been made to determine whether the piano may be improved by altering the materials of the component parts which are traditionally fabricated in timber. Modal analysis and sound level measurements of an upright piano has shown that the radiation from the case is at least 20 dB lower than the radiation from the soundboard, and therefore the case is not a significant determinant of piano tone. A method was developed for separating piano sound and vibrations into broadband and tonal components and used to compare the performance of upright and grand pianos. Using this method it was found that the broadband vibration level was twice as high in the uprights as in the grands. A finite element model of an upright piano was developed and used to demonstrate that replacing the keybed with a higher impedance material than conventionally used would reduce the key vibration level, and hence bring the uprights closer in performance to grand pianos, and improve the 'feel' of the instrument for the player. The keybed of one of a pair of identical pianos was replaced with high density fibreboard, and subsequent objective measurements showed that the broadband component of key vibrations was reduced by 3.2 dB while the radiated sound was unchanged. A controlled subjective comparison between the modified and unmodified pianos undertaken by experienced players showed that a statistically significant number preferred the modified piano, and that the upright piano had been improved. / Acoustics Research Centre, Department of Mechanical Engineering, Foundation for Research Science and Technology, Fletcher Wood Panels.

This thesis offers one step in a direction that will help consumers make better choices in response to a growing demand for a more sustainable living (Grant 2008, Pollan 2008). In a world of seismic economic, environmental and social change the need for a more sustainable way of behaving is rapidly becoming a priority for mere survival (Porritt 2006). Indeed, it has been suggested that the collapse of economic growth in 2008 has primarily been the result of a dependence on outmoded models of consumption (Hamilton 2003, James 2008). The first section of the thesis documents as a narrative the shift from a label design, which is the result of a research paper, to the launch of a food brand within a university community, which is the commercial outcome of research. The second section of the thesis is the study that examines a nascent label design consisting of a list of ingredients as semiotic triggers that inform the consumer about the product at the point of purchase. The methodology is drawn from mediated discourse analysis (Scollon 2005, Norris & Jones 2005) and multimodal discourse analysis where each mode is viewed as a system of representation with rules and regularities attached to it (Kress & van Leeuwen 2006). I focus on the nascent shift in modal values of packaging design within the site of engagement of a supermarket. The site of engagement is where mediated actions at moments in time and space occur (Norris & Jones 2005). These mediated actions are the focus of attention of the relevant participants (Scollon 2005), and operate at different levels of attention (Norris 2004). The third section contains the appendices.

A study of vibrations and sound radiation in upright and grand pianos has been made to determine whether the piano may be improved by altering the materials of the component parts which are traditionally fabricated in timber. Modal analysis and sound level measurements of an upright piano has shown that the radiation from the case is at least 20 dB lower than the radiation from the soundboard, and therefore the case is not a significant determinant of piano tone. A method was developed for separating piano sound and vibrations into broadband and tonal components and used to compare the performance of upright and grand pianos. Using this method it was found that the broadband vibration level was twice as high in the uprights as in the grands. A finite element model of an upright piano was developed and used to demonstrate that replacing the keybed with a higher impedance material than conventionally used would reduce the key vibration level, and hence bring the uprights closer in performance to grand pianos, and improve the 'feel' of the instrument for the player. The keybed of one of a pair of identical pianos was replaced with high density fibreboard, and subsequent objective measurements showed that the broadband component of key vibrations was reduced by 3.2 dB while the radiated sound was unchanged. A controlled subjective comparison between the modified and unmodified pianos undertaken by experienced players showed that a statistically significant number preferred the modified piano, and that the upright piano had been improved. / Acoustics Research Centre, Department of Mechanical Engineering, Foundation for Research Science and Technology, Fletcher Wood Panels.

A study of vibrations and sound radiation in upright and grand pianos has been made to determine whether the piano may be improved by altering the materials of the component parts which are traditionally fabricated in timber. Modal analysis and sound level measurements of an upright piano has shown that the radiation from the case is at least 20 dB lower than the radiation from the soundboard, and therefore the case is not a significant determinant of piano tone. A method was developed for separating piano sound and vibrations into broadband and tonal components and used to compare the performance of upright and grand pianos. Using this method it was found that the broadband vibration level was twice as high in the uprights as in the grands. A finite element model of an upright piano was developed and used to demonstrate that replacing the keybed with a higher impedance material than conventionally used would reduce the key vibration level, and hence bring the uprights closer in performance to grand pianos, and improve the 'feel' of the instrument for the player. The keybed of one of a pair of identical pianos was replaced with high density fibreboard, and subsequent objective measurements showed that the broadband component of key vibrations was reduced by 3.2 dB while the radiated sound was unchanged. A controlled subjective comparison between the modified and unmodified pianos undertaken by experienced players showed that a statistically significant number preferred the modified piano, and that the upright piano had been improved. / Acoustics Research Centre, Department of Mechanical Engineering, Foundation for Research Science and Technology, Fletcher Wood Panels.