Inspection of parts with complex geometry and welds with structural health monitoring techniques

Structural Health Monitoring (SHM) systems were developed to evaluate the integrity of a system during operation, and to quickly identify the maintenance problems. They will be used in future aerospace vehicles to improve safety, reduce cost and minimize the maintenance time of a system. Many SHM systems were already developed to evaluate the integrity of plates and used in marine structures. Their implementation in manufacturing processes is still expected. The application of SHM methods for complex geometries and welds are two important challenges in this area of research. This research work started by studying the characteristics of piezoelectric actuators, and a small energy harvester was designed. The output voltages at different frequencies of vibration were acquired to determine the nonlinear characteristics of the piezoelectric stripe actuators. The frequency response was evaluated experimentally. AA battery size energy harvesting devices were developed by using these actuators. When the round and square cross section devices were excited at 50 Hz frequency, they generated 16 V and 25 V respectively. The Surface Response to Excitation (SuRE) and Lamb wave methods were used to estimate the condition of parts with complex geometries. Cutting tools and welded plates were considered. Both approaches used piezoelectric elements that were attached to the surfaces of considered parts. The variation of the magnitude of the frequency response was evaluated when the SuRE method was used. The sum of the square of the differences was calculated. The envelope of the received signal was used for the analysis of wave propagation. Bi-orthogonal wavelet (Binlet) analysis was also used for the evaluation of the data obtained during Lamb wave technique. Both the Lamb wave and SuRE approaches along with the three methods for data analysis worked effectively to detect increasing tool wear. Similarly, they detected defects on the plate, on the weld, and on a separate plate without any sensor as long as it was welded to the test plate.

An integrated multi-agent framework for optimizing time, cost and environmental impact of construction processes

Environmentally conscious construction has received a significant amount of research attention during the last decades. Even though construction literature is rich in studies that emphasize the importance of environmental impact during the construction phase, most of the previous studies failed to combine environmental analysis with other project performance criteria in construction. This is mainly because most of the studies have overlooked the multi-objective nature of construction projects. In order to achieve environmentally conscious construction, multi-objectives and their relationships need to be successfully analyzed in the complex construction environment. The complex construction system is composed of changing project conditions that have an impact on the relationship between time, cost and environmental impact (TCEI) of construction operations. Yet, this impact is still unknown by construction professionals. Studying this impact is vital to fulfill multiple project objectives and achieve environmentally conscious construction. This research proposes an analytical framework to analyze the impact of changing project conditions on the relationship of TCEI. This study includes green house gas (GHG) emissions as an environmental impact category. The methodology utilizes multi-agent systems, multi-objective optimization, analytical network process, and system dynamics tools to study the relationships of TCEI and support decision-making under the influence of project conditions. Life cycle assessment (LCA) is applied to the evaluation of environmental impact in terms of GHG. The mixed method approach allowed for the collection and analysis of qualitative and quantitative data. Structured interviews of professionals in the highway construction field were conducted to gain their perspectives in decision-making under the influence of certain project conditions, while the quantitative data were collected from the Florida Department of Transportation (FDOT) for highway resurfacing projects. The data collected were used to test the framework. The framework yielded statistically significant results in simulating project conditions and optimizing TCEI. The results showed that the change in project conditions had a significant impact on the TCEI optimal solutions. The correlation between TCEI suggested that they affected each other positively, but in different strengths. The findings of the study will assist contractors to visualize the impact of their decision on the relationship of TCEI.

Hydrologic processes on tree islands in the Everglades (Florida, USA): tracking the effects of tree establishment and growth

The hydrodynamics of tree islands during the growth of newly planted trees has been found to be influenced by both vegetation biomass and geologic conditions. From July 2007 through June 2009, groundwater and surface-water levels were monitored on eight recently planted tree islands at the Loxahatchee Impoundment Landscape Assessment (LILA) facility in Boynton Beach, Florida, USA. Over the 2-year study, stand development coincided with the development of a water-table depression in the center of each of the islands that was bounded by a hydraulic divide along the edges. The water-table depression was greater in islands composed of limestone as compared to those composed of peat. The findings of this study suggest that groundwater evapotranspiration by trees on tree islands creates complex hydrologic interactions between the shallow groundwater in tree islands and the surrounding surface water and groundwater bodies.

The impact of cross -training on team processes and performance

Recently, researchers have begun to investigate the benefits of cross-training teams. It has been hypothesized that cross-training should help improve team processes and team performance (Cannon-Bowers, Salas, Blickensderfer, & Bowers, 1998; Travillian, Volpe, Cannon-Bowers, & Salas, 1993). The current study extends previous research by examining different methods of cross-training (positional clarification and positional modeling) and the impact they have on team process and performance in both more complex and less complex environments. One hundred and thirty-five psychology undergraduates were placed in 45 three-person teams. Participants were randomly assigned to roles within teams. Teams were asked to “fly” a series of missions on a PC-based helicopter flight simulation. ^ Results suggest that cross-training improves team mental model accuracy and similarity. Accuracy of team mental models was found to be a predictor of coordination quality, but similarity of team mental models was not. Neither similarity nor accuracy of team mental models was found to be a predictor of backup behavior (quality and quantity). As expected, both team coordination (quality) and backup behaviors (quantity and quality) were significant predictors of overall team performance. Contrary to expectations, there was no interaction between cross-training and environmental complexity. Results from this study further cross-training research by establishing positional clarification and positional modeling as training strategies for improving team performance. ^

A model of school managerial control : the systematic analysis of managerial behaviors, processes, and indicators

The theoretical construct of control has been defined as necessary (Etzioni, 1965), ubiquitous (Vickers, 1967), and on-going (E. Langer, 1983). Empirical measures, however, have not adequately given meaning to this potent construct, especially within complex organizations such as schools. Four stages of theory-development and empirical testing of school building managerial control using principals and teachers working within the nation's fourth largest district are presented in this dissertation as follows: (1) a review and synthesis of social science theories of control across the literatures of organizational theory, political science, sociology, psychology, and philosophy; (2) a systematic analysis of school managerial activities performed at the building level within the context of curricular and instructional tasks; (3) the development of a survey questionnaire to measure school building managerial control; and (4) initial tests of construct validity including inter-item reliability statistics, principal components analyses, and multivariate tests of significance. The social science synthesis provided support of four managerial control processes: standards, information, assessment, and incentives. The systematic analysis of school managerial activities led to further categorization between structural frequency of behaviors and discretionary qualities of behaviors across each of the control processes and the curricular and instructional tasks. Teacher survey responses (N=486) reported a significant difference between these two dimensions of control, structural frequency and discretionary qualities, for standards, information, and assessments, but not for incentives. The descriptive model of school managerial control suggests that (1) teachers perceive structural and discretionary managerial behaviors under information and incentives more clearly than activities representing standards or assessments, (2) standards are primarily structural while assessments are primarily qualitative, (3) teacher satisfaction is most closely related to the equitable distribution of incentives, (4) each of the structural managerial behaviors has a qualitative effect on teachers, and that (5) certain qualities of managerial behaviors are perceived by teachers as distinctly discretionary, apart from school structure. The variables of teacher tenure and school effectiveness reported significant effects on school managerial control processes, while instructional levels (elementary, junior, and senior) and individual school differences were not found to be significant for the construct of school managerial control.

Coupled symplectic maps as models for subdiffusive processes in disordered Hamiltonian lattices

Acknowledgements One of us (T. B.) acknowledges many interesting discussions on coupled maps with Professor C. Tsallis. We are also grateful to the anonymous referees for their constructive feedback that helped us improve the manuscript and to the HPCS Laboratory of the TEI of Western Greece for providing the computer facilities where all our simulations were performed. C. G. A. was partially supported by the “EPSRC EP/I032606/1” grant of the University of Aberdeen. This research has been co-financed by the European Union (European Social Fund - ESF) and Greek national funds through the Operational Program “Education and Lifelong Learning” of the National Strategic Reference Framework (NSRF) - Research Funding Program: THALES - Investing in knowledge society through the European Social Fund.

Coupled symplectic maps as models for subdiffusive processes in disordered Hamiltonian lattices

Acknowledgements One of us (T. B.) acknowledges many interesting discussions on coupled maps with Professor C. Tsallis. We are also grateful to the anonymous referees for their constructive feedback that helped us improve the manuscript and to the HPCS Laboratory of the TEI of Western Greece for providing the computer facilities where all our simulations were performed. C. G. A. was partially supported by the “EPSRC EP/I032606/1” grant of the University of Aberdeen. This research has been co-financed by the European Union (European Social Fund - ESF) and Greek national funds through the Operational Program “Education and Lifelong Learning” of the National Strategic Reference Framework (NSRF) - Research Funding Program: THALES - Investing in knowledge society through the European Social Fund.

Studentized U-quantile processes under dependence with applications to change-point analysis

Peer reviewed

Geochemistry of lower sheeted dike complex samples of ODP Holes 137-504B and 140-504B

Rocks of the lower sheeted dike complex of Hole 504B sampled during Leg 140 were analyzed for major and trace element compositions to investigate the effects of igneous processes and hydrothermal alteration on the compositions of the rocks. The rocks are relatively uniform in composition and similar to the shallower dikes. They are moderately evolved mid-ocean-ridge basalts (MORB) with relatively high MgO (7.9-10 wt%) and Mg# (0.60-0.70), and have unusually low incompatible element contents (TiO2 = 0.42-1.1 wt%, Zr = 23-62 ppm). Discrete compositional intervals in the hole reflect varying degrees of differentiation, and olivine and plagioclase accumulation in the rocks, and may be related to injection of packets of dikes having similar compositions. Systematic depletions of total REE, Zr, Y, TiO2, and P2O5 in centimeter-size patches are most likely attributed to exclusion of highly differentiated, late-stage interstitial liquids from small portions of the rocks. The rocks exhibit increased H2O+ reflecting hydrothermal alteration. Replacement of primary plagioclase by albite and oligoclase led to local gains of Na2O, losses of CaO, and slightly positive Eu anomalies. Some mobility of P2O5 led to minor increases and decreases in P2O5 contents, and some local mobility of Ti may have occurred during alteration of titanomagnetite to titanite. Higher temperatures of alteration in the lower sheeted dikes led to breakdown of pyroxene and sulfide minerals and losses of Zn, Cu, and S to hydrothermal fluids. Later addition of anhydrite to the rocks in microfractures and replacing plagioclase caused local increases in sulfur contents. The lower sheeted dikes are a major source of metals to hydrothermal fluids for the formation of metal sulfide deposits on and within the seafloor.

Biogeochemical parameters and processes in waters and bottom sediments of the Chukchi Sea

Study of biogeochemical processes in waters and sediments of the Chukchi Sea in August 2004 revealed atypical maxima of biogenic element (N, P, and Si) concentrations and rate of microbial sulfate reduction in the surface layer (0-3 cm) of marine sediments. The C/N/P ratio in organic matter (OM) of this layer does not fit the Redfield-Richards stoichiometric model. Specific features of biogeochemical processes in the sea are likely related to the complex dynamics of water, high primary produc¬tivity (110-1400 mg C/m**2/day), low depth of the basin (<50 m for 60% of the water area), reduced food chain due to low population of zooplankton, high density of zoobenthos (up to 4230 g/m**2), and high activity of microbial processes. Drastic decrease in concentrations of biogenic elements, iodine, total alkalinity, and population of microorganisms beneath the 0-3 cm layer testify to large-scale OM decay at the water-seafloor barrier. Our original experimental data support high annual rate of OM mineralization at the bottom of the Chukchi Sea.

Information ethics in the age of digital labour and the surveillance-industrial complex

Thee rise of computing and the internet have brought about an ethical eld of studies that some term information ethics, computer ethics, digital media ethics, or internet ethics e aim of this contribution is to discuss information ethics’ foundations in the context of the internet’s political economy e chapter rst looks to ground the analysis in a comparison of two information ethics approaches, namely those outlined by Rafael Capurro and Luciano Floridi It then develops, based on these foundations, analyses of the information ethical dimensions of two important areas of social media: one concerns the framing of social media by a surveillance-industrial complex in the context of Edward Snowden’s revelations and the other deals with issues of digital labour processes and issues of class that arises in this context e contribution asks ethical questions about these two phenomena that bring up issues of power, exploitation, and control in the information age It asks if, and if so, how, the approaches of Capurro and Floridi can help us to understand ethico-political aspects of the surveillance-industrial complex and digital labour

Health reforms in Latin America: processes and results

Two types of health reforms in Latin America are analysed: one based on insurance and service commodification and the one referred to the unified public systems of progressive governments. Health insurance with explicit service packages has not fulfilled their purposes of universal coverage, equal access to necessary health services and improvement of health conditions but has opened health as a field of profit making for insurance companies and private health providers. The national health services as a state obligation have developed territorialized health services and widened substantially timely access to the majority of the population. The adoption of an integrated and wide social policy has an impact on population well fare. It faces some problems derived from the old health systems and the power of the insurance and medical complex.

What's in it for us? A case study research about micro sense making processes through the eyes of front line employees, during culture change implementation

Abstract How employees make sense of change is a very complex process. Recently, academics have neglected to research sense making activities in a micro culture implementation context, through the eyes of front line employees. In contrast to a macro view, a micro perspective limits researchers to only look at an individual, departmental or group level. By doing so, we can zoom in on the details of sense making processes that employees use in their daily work life. A macro (organisational) view is based on the notion that there is a general integrated culture that can be found in all organisational units and departments. It is assumed that culture can be researched by using the entire organisation as one single research entity. This thesis challenges this assumption. In case of planned change it is usually the management community who are in charge of the change intervention. Because of their formal hierarchical position, they have the power to abort or initiate change programs. It is perhaps therefore that researchers tend to be focused on the management community rather than on lower level organisational members, such as front line employees. Apart from the micro view, scholars also neglected to research culture change implementation through the eyes of front line employees. This thesis is an attempt to fill these two gaps that currently exists in academic change management publications. The main research question is therefore: From a micro point of view how do front-line employees make sense of the impact of culture change, during the implementation phase? This thesis starts with a literature review which exposes the two main gaps. The most important outcome of this review is that only 2% of the research articles dealt with culture implementation, through the eyes of front line employees. A conceptual research model is built on the integrated sense making theory of Weber and Manning (2001) and the micro variables of Raelin and Cataldo (2011). These theories emphasize elements of sense making in a daily working context. It is likely that front line employees can identify themselves with research elements such as tasks, skills practices, involvement and behaviour. Front line employees were selected, because as lower level organisational members they are usually the change recipients. They are further away from the change initiating scene (usually the management of an organisation) and form a potential sense making ‘hotspot’ that could provide new academic insights. In order to carry out the primary research, two case organisations were selected in the leisure industry. A participative case study research method was chosen. This meant that the researcher worked in the concerning departments of the case organisations. The goal was to observe and interview front line employees, while they were performing their jobs. The most important advantage of this approach is that the researcher temporarily becomes one with the organisation and is therefore able to acquire both formal and informal narratives that front line employees use during sense making activities. It was found that front line employees make sense of organisational change by using a practical approach. They make sense of the change program by carrying out new tasks, developing new skills and sharing best practices. The most noticeable conclusion was that sense making activities predominantly take place at an individual level in relation to change acceptance. Organisational members tend to create a mental equation in order to weigh the advantages against the disadvantages. They evaluate whether the concerning change program is beneficial to them or not. For future research a sense making scheme model is suggested that is based on two methods: an introspection and an action method.

Complete framework for efficient characterisation of non-Markovian processes

A non-Markovian process is one that retains `memory' of its past. A systematic understanding of these processes is necessary to fully describe and harness a vast range of complex phenomena; however, no such general characterisation currently exists. This long-standing problem has hindered advances in understanding physical, chemical and biological processes, where often dubious theoretical assumptions are made to render a dynamical description tractable. Moreover, the methods currently available to treat non-Markovian quantum dynamics are plagued with unphysical results, like non-positive dynamics. Here we develop an operational framework to characterise arbitrary non-Markovian quantum processes. We demonstrate the universality of our framework and how the characterisation can be rendered efficient, before formulating a necessary and sufficient condition for quantum Markov processes. Finally, we stress how our framework enables the actual systematic analysis of non-Markovian processes, the understanding of their typicality, and the development of new master equations for the effective description of memory-bearing open-system evolution.

Fibronectin/phosphorylcholine coatings on fluorocarboned surfaces: a study upon adsorption and grafting processes

Depuis ces dernières décennies, le domaine des biomatériaux a connu un essor considérable, évoluant de simples prothèses aux dispositifs les plus complexes pouvant détenir une bioactivité spécifique. Outre, le progrès en science des matériaux et une meilleure compréhension des systèmes biologiques a offert la possibilité de créer des matériaux synthétiques pouvant moduler et stimuler une réponse biologique déterminée, tout en améliorant considérablement la performance clinique des biomatériaux. En ce qui concerne les dispositifs cardiovasculaires, divers recouvrements ont été développés et étudiés dans le but de modifier les propriétés de surface et d’améliorer l’efficacité clinique des tuteurs. En effet, lorsqu’un dispositif médical est implanté dans le corps humain, son succès clinique est fortement influencé par les premières interactions que sa surface établit avec les tissus et les fluides biologiques environnants. Le recouvrement à la surface de biomatériaux par diverses molécules ayant des propriétés complémentaires constitue une approche intéressante pour atteindre différentes cibles biologiques et orienter la réponse de l’hôte. De ce fait, l’élucidation de l’interaction entre les différentes molécules composant les recouvrements est pertinente pour prédire la conservation de leurs propriétés biologiques spécifiques. Dans ce travail, des recouvrements pour des applications cardiovasculaires ont été créés, composés de deux molécules ayant des propriétés biologiques complémentaires : la fibronectine (FN) afin de promouvoir l’endothélialisation et la phosphorylcholine (PRC) pour favoriser l’hémocompatibilité. Des techniques d’adsorption et de greffage ont été appliquées pour créer différents recouvrements de ces deux biomolécules sur un polymère fluorocarboné déposé par traitement plasma sur un substrat en acier inoxydable. Dans un premier temps, des films de polytétrafluoroéthylène (PTFE) ont été utilisés en tant que surface modèle afin d’explorer l’interaction de la PRC et de la FN avec les surfaces fluorocarbonées ainsi qu’avec des cellules endothéliales et du sang. La stabilité des recouvrements de FN sur l’acier inoxydable a été étudiée par déformation, mais également par des essais statiques et dynamiques sous-flux. Les recouvrements ont été caractérisés par Spectroscopie Photoéléctronique par Rayons X, immunomarquage, angle de contact, Microscopie Électronique de Balayage, Microscopie de Force Atomique et Spectrométrie de Masse à Ionisation Secondaire à Temps de Vol (imagerie et profilage en profondeur). Des tests d’hémocompatibilité ont été effectués et l’interaction des cellules endothéliales avec les recouvrements a également été évaluée. La FN greffée a présenté des recouvrements plus denses et homogènes alors que la PRC quant à elle, a montré une meilleure homogénéité lorsqu’elle était adsorbée. La caractérisation de la surface des échantillons contenant FN/PRC a été corrélée aux propriétés biologiques et les recouvrements pour lesquels la FN a été greffée suivie de l’adsorption de la PRC ont présenté les meilleurs résultats pour des applications cardiovasculaires : la promotion de l’endothélialisation et des propriétés d’hémocompatibilité. Concernant les tests de stabilité, les recouvrements de FN greffée ont présenté une plus grande stabilité et densité que dans le cas de l’adsorption. En effet, la pertinence de présenter des investigations des essais sous-flux versus des essais statiques ainsi que la comparaison des différentes stratégies pour créer des recouvrements a été mis en évidence. D’autres expériences sont nécessaires pour étudier la stabilité des recouvrements de PRC et de mieux prédire son interaction avec des tissus in vivo.