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The main issues of molten salts in concentrated solar power plants are their poor thermophysical properties and corrosion issues. To improve their properties nanoparticles are doped in molten salts. These suspended particles have an effect not only on the thermal, but also other properties such as viscosity and wettability, the latter having often been overlooked. In this work molten nitrate salts are doped with amorphous SiO₂ and graphite particles. A series of contact angle measurements are conducted to study the effects of nanoparticle concentration, composition, particle geometry, temperature and surface type. A small fraction of nanoparticles leads to a shift of the transition from non-wetting to wetting at higher temperatures. Furthermore, wettability studies on different surfaces provide insights into the physiochemical mechanism of molten salt corrosion. Molecular Dynamics simulations of the nitrate salts-based silica nanofluids are also conducted. Novel interatomic parameters are calculated for the molten nitrate salts as well as the α-SiO₂ and are used to predict the wetting behavior of the molten NaNO₃ and KNO₃ and their mixtures with and without a-SiO₂ nanoparticles, in order to provide a better understanding of the wetting behavior of molten salt based nanofluids.

As-Is Building Information Models aid in the management, maintenance and renovation of existing buildings. However, most existing buildings do not have an accurate geometric depiction of their As-Is conditions. The process of generating As-Is models of existing structures involves practitioners, who manually convert Point Cloud Data (PCD) into semantically meaningful 3D models. This process requires a significant amount of manual effort and time. Previous research has been able to model objects by segmenting the point clouds into planes and classifying each one separately into classes, such as walls, floors and ceilings; this is insufficient for modelling, as BIM objects are comprised of multiple planes that form volumetric objects. This thesis introduces a novel method that focuses on the geometric creation of As-Is BIMs with enriched information. It tackles the problem by detecting objects, modelling them and enriching the model with spaces and object adjacencies from PCD. The first step of the proposed method detects objects by exploiting the relationships the segments should satisfy to be grouped into one object. It further proposes a method for detecting slabs with variations in height by finding local maxima in the point density. The second step models the geometry of walls and finally enriches the model with closed spaces encoded in the Industry Foundation Classes (IFC) standard. The method uses the point cloud density of detected walls to determine their width by projecting the wall into two directions and finding the edges with the highest density. It identifies adjacent walls by finding gaps or intersections between walls and exploits walls adjacency for correcting their boundaries, creating an accurate 3D geometry of the model. Finally, the method detects closed spaces by using a shortest-path algorithm. The method was tested on three original PCD which represent office floors. The method detects objects of class walls, floors and ceilings in PCD with an accuracy of approximately 96%. The precision and recall for the room detection were found to be 100%.

Corporate social responsibility (CSR) has an ever-increasing role in the way commercial businesses operate. Team sport organisations are not immune to this trend. CSR is a strategic issue for sport organisations, with professional teams across a range of sports and national contexts now modifying their organisational structure by establishing charitable foundations tasked with delivering their CSR content. These structural changes inevitably bring in new organisational actors who, in varying degrees, influence ̀the actual implementation of CSR in the professional sports team context. Organisational complexity is therefore increasing regarding CSR, as is the need to capture its elements at both cross-organisational and individual levels. This is especially important given that, unlike mainstream (corporate) foundations that deal directly with a ‘parent’ company, professional sport leagues often mandate the implementation of CSR through central funding mechanisms. This in turn emphasises the intricacy of the process and the dynamics amongst organisational actors at various levels. To date, no studies have attempted to address this complexity. The present thesis aims to help fill the gap by examining the managerial decision-making process in the organisational context of charitable foundations established by English professional football clubs. The current study employs a grounded theory methodology as it aims to develop a substantive theory of how managers responsible for the formulation and implementation of CSR-related programmes in English football make professional decisions. The research utilises the Straussian variant of grounded theory, which accepts that humans shape their institutions as much as institutions shape people. The study also seeks cognitive similarity, a concept that implies some form of similar attribution of meaning, understanding or interpretation amongst individuals in multiple organisations. Although its purpose was to develop an individual-based substantive theory grounded in the way managers make decisions regarding CSR, throughout the focus has been on decision-making itself rather than on the individuals who facilitate this process. The study is populated with the top two divisions of English football and employs two data collection techniques: organisational documents and semi-structured interviews. The fieldwork took place in three different phases, with the first ̀consisting of two sub-phases. Phase 1a emphasised the analysis of organisational documents (a total of 25 documents from 16 football organisations), while the following phases of the fieldwork were based on constant comparative data analysis from 32 interviews. The theoretical framework that emerged from this study is one of assessable transcendence; in a conceptually abstract fashion, ‘assessable transcendence’ concerns a process that, fortified ̀by passion, contingent on trust, sustained by communication and substantiated by factual performance, enables the formulation and implementation of CSR-related programmes in this context. The social process that emerged from this study, therefore, consists of an intrinsic (that is, passion) and an extrinsic (that is, trust) stimulus, both of which are central components of the micro-social process transcending. These two stimuli, however, require the support of both internal and external communication (abstractly expressed through the micro-social process manoeuvring), and thus all three together form a ‘coalition’ which can enhance both business and social performance (largely expressed by the first ̀two micro-social processes, namely safeguarding and harmonising). Accordingly, two interrelated aspects of the decision-making process constitute a common thread in this research: (a) the recognition that social consciousness stimulates the process of assessable transcendence in an indispensable and limitless way, and (b) an understanding that transcendence cannot occur without either continuous achievement or the dissemination of concrete ‘CSR impact’ in social and business forms alike (hence assessable). The significance of this doctoral thesis for the sport management literature is four-fold. First, it focuses on the individual level of analysis, thereby offering a framework that explains the decision-making of those individuals responsible for the application of CSR in professional team sport organisations. By doing so, it bridges the micro/macro divide by integrating the micro-domain’s focus on individuals (i.e., foundation managers) with those of the meso- and macro- domains. Second, it moves away from mono-theoretical approaches that have been mainly used for the examination of CSR in the sporting context. By doing so, it illustrates that different, and often opposing, theoretical approaches may be needed in order to fully capture and theoretically explain the way in which the CSR practice occurs. Third, it shifts the focus of scholarly activity away from CSR content-based research towards more process-oriented approaches. CSR content research does little to explain how professional teams achieve and maintain such positioning through deliberate and trial-and-error CSR actions initiated by the individuals therein. Fourth, an in relation to the previous point, it employs a process-oriented methodology (namely, grounded theory) whose utilisation in sport management research has been either non-existent or a ‘pick and mix’ practice. By doing so, the current thesis responds to calls for internal consistency and methodological coherence, thereby adding to the limited number of studies that have utilised this methodology in a rounded manner. The theoretical framework presented in this dissertation has emerged from exploratory study. As such, the four micro-social processes, their associative meanings and, more importantly, the four principal concepts that hold assessable transcendence are regarded as tentative and require substantiation through further research. To this end, a number of research propositions are offered that can serve as a starting point towards a continued exploration of those moderating and mediating factors on the formulation and implementation of CSR in team sport organisations.

My thesis contributes to research on the consequences of labour market institutions for employment using an original Greek dataset I have constructed, the TERS. This survey gives a representative sample of micro-enterprises as well as small and medium enterprises. I investigate whether firms use temporary (and family) employment as "escape" routes from mandated wage floors (corporate collective wage agreements) and working conditions floors (employment protection legislation (EPL) monitored by the Labour Inspectorate). My basic hypothesis is thus that temporary and family work are forms of insurance for the poorer firms which cannot cope with EPL coupled with wage floors. I find significant wage floor effects, in particular, where firms have many workers at the minimum (or below it - in the case of "grey" market firms), they are more likely to employ temporary workers. The implication is that where firms have many workers on the minimum they are likely to worry about the possibility of a rise in the minimum, and hence will employ on a more temporary basis. Wage floors thus matter. I also find significant EPL effects. In particular, firms whose managers believe that temps have low EPL are more likely to employ temps, ceteris paribus. My result thus shows that an advantage of employing temps is quite simply their low EPL. My findings for family worker employment are similarly confirmatory. Workplaces in the "grey" category, paying low wages probably below nationally agreed rates, are much more likely to employ a high percentage of family workers, other things equal-they are easy to layoff, and less likely to complain about low wages. The policy implication of my research is therefore that Greece's wages and working conditions floors indeed appear both to promote precarious temporary employment, and also small-scale family business, which is not the way to grow and prosper.

This thesis investigates the impact of accounting standard IAS39 on banking institutions in Greece and the UK.  It specifically addresses preparers’ perceptions of that standard’s effects on the banking books of banks. The research involves a mixed methodology, namely: (i) a survey analysis of the perceptions of banking practitioners in Greece and the UK, in order to identify the standard’s impact on the banking sector as well as to gauge the standard’s acceptance of banks, in order to facilitate a deeper understanding of the implications of the standard for their organisations.  ‘Elite’ interviews also advocate that such high powered individuals are the key holders to privy information. The results suggest that IAS39 is a highly controversial standard that introduces concerns not only for the banks’ valuation of assets and liabilities but also regulatory concerns over issues of policy formulation and stability.  Generally, bankers are negative and largely sceptical of the standard, on the grounds of relevance and reliability.  They do not view the standard as particularly useful, relevant, reliable or transparent for banking disclosures and financial stability when compared to the current mixed methodology approach followed currently for the valuation of assets and liabilities in the banking books of banks.  Most concerns revolve around the standard’s effects on valuation of assets and liabilities, provisioning and hedging issues and bank capital management for regulatory capital purposes. In the introduction of accounting standards attention should be paid to the nature of the industry and the system (i.e. credit versus market-based) in which firms operate, as well as to establishing particular methodologies.  It touches upon a contemporary issue of critical topical and international interest, of how accounting information standards relate to the systemic, operating, credit, market and liquidity risks of a modern, internationalised banking system.

Sandwich structural elements consist of two metallic or non-metallic laminated skins separated by a lightweight thicker core layer, maximizing in this manner weight efficiency and structural performance. From the available core configurations, phenolic resin impregnated Nomex® paper honeycomb cores are highly preferred in aerospace industry because of their lower density, excellent thermal resistance, and curved shape adaptability. Despite the inherent benefits of Nomex® paper sandwich structures, their impact response is still questionable. Towards this direction, a series of simulated hail ice impact tests was performed on flat carbon fiber sandwich panels via gas gun test apparatus to assess Nomex® paper core damage. Impact test results revealed significant core crushing in the form of cell collapse without any externally visible signs of damage on the impacted skin surface.Since high-velocity impact tests on sandwich panels are by nature highly complex, the out-of-plane response of over-expanded Nomex® cores was phenomenologically characterized through quasi-static flatwise compression tests on stabilized sandwich core coupons. Localized detachment and crushing of the phenolic resin accumulation regions between adjacent cell walls, were the main damage modes that triggered honeycomb collapse.X-ray Computed Tomography (CT) scans were also employed to assess damage modes on the interior cells of tested sandwich core coupons. Given several sets of X-ray CT scan 3D data, an automated B-spline image-based reconstruction scheme was developed to numerically capture scanned honeycomb core geometries. Different applications of the proposed reconstruction scheme are going to be presented. Finally, the contribution of the phenolic resin accumulation regions on the out-of-plane response was investigated through numerical modeling of the reconstructed B-spline geometry. To this end, constituent material properties were determined through uniaxial tensile testing on in-situ phenolic resin impregnated paper coupons as well as bare aramid paper coupons. Numerical simulations on sandwich cores without the phenolic resin accumulations yielded significant reduction of the collapse limit, validating in this way the experimental observations.

Graphical models have established themselves as fundamental tools through which to understand complex relationships in high-dimensional datasets. Applications abound, a pertinent example being neuroimaging where Gaussian graphical models are employed to model statistical dependencies across spatially remote brain regions. Often such models are estimated under regularization penalties which help to enforce properties such as sparsity. Much of the current methodology is rooted on the assumption that the same covariance structure characterizes all observations and may be summarized using a single graphical model. However, such an assumption is untenable in the context of many applications. In order to address this issue, we propose a host of algorithms through which to accurately estimate Gaussian graphical models in the context of data with heterogeneous covariance structure. Formally, this thesis is focused in studying graphical models in two distinct manifestations of heterogeneity in covariance structure. The first relates to the task of estimating time-varying graphical models and two algorithms are proposed to this end. A related challenge is associated with the choice of regularization parameter: in the presence of variable covariance structure such a parameter is both difficult to estimate and potentially time-varying itself. In order to address these challenges, a novel framework is proposed through which to iteratively tune this parameter. The second manifestation is related to the presence of heterogeneity in covariance structure across multiple related graphical models. In such a setting scientific objectives consist in inferring the covariance structure shared across all graphs together with the idiosyncrasies of each specific graph. A related objective which is often overlooked consists of quantifying variability across all graphs. A novel algorithm is proposed through which to simultaneously address the aforementioned objectives.

Object classification by learning from data is a vast area of statistics and machine learning. Within classification, unlabelled data may be plentiful, allowing a few objects to be chosen for labelling by an expert. Systematically choosing these few objects can maximise classifier improvement: this is the problem of active learning (AL). Many heuristic methods coexist with theoretical approaches making substantial assumptions, leaving a gulf between theory and practice. There is a plethora of applications demanding better algorithms and understanding. Experimental studies give a very mixed picture of results, making AL performance rather mysterious. To explore this, a large scale empirical study examines performance in detail. One approach to active learning is to consider the optimal selection behaviour. Defining optimality by classifier improvement produces a new characterisation of optimal AL behaviour. This optimum yields theoretical insights and practical algorithms for applications, unifying theory and practice. This approach is model retraining improvement (MRI), a novel statistical estimation framework for AL. MRI generates a new guarantee for AL, that an unbiased MRI estimator should outperform random selection on average. New statistical AL algorithms are constructed to estimate the MRI optimum, revealing intricate estimation issues. One new algorithm in particular performs strongly in a large-scale experimental study, compared to standard AL methods. MRI is entirely general in terms of problems, classifiers and loss functions. AL shows that classification examples are not created equal; this diversity of example quality implies that systematic selection and modification can both improve classifier performance. This idea is extended to classification, where label improbability gives a new definition of quality (improbability given the covariates). Handling improbable labels (HIL) defines actions to modify the training data, by pruning, relabelling and weighting, to reduce the impact of the improbable labels. Two large experimental studies establish the effectiveness of HIL algorithms.

Financial time series analysis is a highly empirical discipline concerned with the evolution of the price of an asset. The key feature that distinguishes financial time series from time series of other scientific domains is the element of uncertainty that they contain. The recent financial crisis has tested the capabilities of several existing models and evidenced the need for methods able to deal with the high complexity and the non-stationary characteristics of the data observed in financial markets. The objective of this thesis is to provide a better understanding of financial time series, to enhance the abilities of existing methods, especially their predictive performance but also to develop novel methods which aim to provide inferences in the presence of non-stationarities and reduce the complexity of high dimensional tasks. To this end, the memory in the magnitude and the memory in the sign of logarithmic returns is studied and a novel model is constructed whose fit suggests that long memory might be present in the volatility process and that when memory in the sign increases so does the memory in the magnitude. Additionally, wavelets are employed for that they operate in both the time and frequency domains. Thus, classic time series models and other methods extensively used in the time domain are deployed across different frequency bands to combine knowledge from both domains and provide information that might not be accessible otherwise. In particular, the volatility process is modeled in the time domain after some of the noisy behavior that exists in high frequencies, which might also contain outliers, is neglected. Moreover, the volatility process is modeled directly in the wavelet domain in a scale-by- scale manner in an effort to improve the forecasting performance. Furthermore, we attempt to detect changes in the autocorrelation function of a process, which result in changes in the spectral density function, by monitoring the wavelet variance across different multiresolution scales.

In my thesis, I examine the role of character friendship for the agent’s moral development in Aristotle’s ethics. I contend that we should divide character friendship in two categories: a) character friendship between completely virtuous agents, and, b) character friendship between unequally developed, or, equally developed, yet not completely virtuous agents. Regarding the first category, I argue that this highest form of friendship provides the opportunity for the agent to advance his understanding of certain virtues through the help of his virtuous friend. This process can be expressed in two ways. In the first way, I take character friendship in (a) as a relationship that is based on mutual relinquishing of opportunities for action or giving up external goods based on each agent’s needs. This process helps the agents develop their character in certain virtues which have remained slightly underdeveloped than others due to nature (NE 1144b4-7), or development (Politics 1329a9ff). This means, for instance, that if agent A is wealthy and his friend B is a middle class worker and they win the lottery together, A will relinquish his share of money to his friend so that he will be able to practice the virtue of magnificence; a virtue that his previous financial condition prevented him from developing appropriately. The second process is rather different and new in scholarly debate concerning Aristotle’s theory of moral development. I suggest that the completely virtuous agent is able to further develop his character through a process I will describe as interpretative mimesis. In this process, the agent receives the form of his friend’s action and is able to apply this pattern of behaviour in a situation that he thinks is appropriate. I have to highlight though the fact the fact that he does not just ape his friend’s action. Instead, he interprets the action based on his skills and abilities and the demands of the situations he faces. Thus, this pattern works as an extra epistemological tool in the agent’s hand in new and challenging moral situations. Now, case (b) comes on the opposite side of the majority of scholars’ view on character friendship. They think that Aristotle reserves character friendship only for completely virtuous agents. I argue that this is not the correct approach, and that less than completely virtuous agents can take part in character friendships as well. This view has the advantage of making character friendship in (b) a tool in Aristotle’s hands for his agents of lower moral level to develop their understanding of virtue and its applications. I propose that the route of moral development in case (b) resembles the one in the second process of case (a). Namely, the agent receives the form of his friend’s action and uses it as a pattern in some new situation he has to face. I will not name the process though as “interpretative” or any kind of mimesis. The reason for this is that Aristotle gives us textual evidence (NE 1172a9-14) for an imitative method of moral development only for the second process of case (a). I will take case (b) then as a pattern guide application of my friend’s action which we could call pre-interpretative mimesis period of the agent’s moral development. If my arguments are correct then character friendship is much more valuable than scholars thought. Our friends turn out to be examples of good action who guide us through the sweaty and painful path that is called virtue. And this path never stops; even if we have become “moral heroes”; or, put it differently, “masters” of practical wisdom.

This thesis evaluated the role of cardiovascular computed tomography (CCT) in assessing the left ventricular (LV) myocardium. The technical and clinical performance of single-slice CT for attenuation correction (CTAC) of SPECT myocardial perfusion scintigraphy (MPS) was evaluated. Early and delayed multi-slice CT (eCCT and dCCT respectively) myocardial enhancement patterns were validated against SPECT MPS (single-source CCT) and cardiovascular magnetic resonance imaging (CMR, dual-source CCT) for detection of chronic myocardial infarction (MI), as were CCT measures of segmental LV wall thickness and global and regional LV function. Impact of cardiac phase and reconstruction kernel on agreement with SPECT MPS was also measured. The following results were shown: CTAC showed no benefits on MPS report or reporter confidence when studied in a way that reflects clinical practice; dCCT best identifies segmental MI, showing good agreement and high specificity, negative predictive value and accuracy compared with SPECT MPS and CMR; choice of smooth or medium-smooth reconstruction kernel appears relatively unimportant; dual-energy dCCT may be more sensitive for segmental MI on CMR; CCT end-systolic wall thickness is a better predictor of myocardial scarring on MPS and CMR than end-diastolic wall thickness; CCT overestimates end-systolic and end-diastolic volumes on MPS but LV ejection fraction is equivalent; CCT shows no systematic differences in measures of global LV function when compared to CMR; measures of regional ventricular function on CCT show excellent and good agreement with MPS and CMR respectively; inter- and intraobserver agreement for dCCT myocardial enhancement patterns and regional LV function is excellent.