A theoretical study is conducted for the lateral torsional buckling of wooden beam-deck assemblies consisting of twin beams braced by tongue-and-groove decking at the top. Two models are developed, each with a series of analytical and numerical solutions formulated. The first model targets twin-beam-deck assemblies where deck boards and other components are detailed to provide full continuous lateral restraint while the second model is built for situations where the beams are allowed to sway laterally and the relative lateral movement between the beams is partially restrained by the deck boards. In the first model, focus is on wind uplift while in the second model, both gravity and uplift loading scenarios are investigated. In the first model, an energy method is adopted and the principle of stationary potential energy is evoked to formulate closed-form solutions, energy-based solutions and a finite element solution. The validity of the present solutions is verified against a finite element based ABAQUS model. Similarly, a family of solutions is developed under the sway model and verified against the ABAQUS. Parametric studies are conducted for both models to examine the effects of various variables on the buckling capacity. A comparative investigation on the behavioral difference between the two models under ABAQUS is also presented. Overall, the restraining effects of deck boards bracing either on the beam compression or tension side is observed to have a significant influence on the lateral torsional buckling capacity of the twin-beam-deck assemblies.

Reiki is an ancient, energy healing practice. But how can Reiki be presented in a more relatable, everyday way, so more people try it to improve their wellbeing? That is the question that is behind and fuels this project. The report explores how Reiki can, and has helped people with their physical and mental wellbeing. Through research, workshops and personal experiences it attempts to formulate a positive, more grounded view of Reiki that could reach out to more people, so they consider adding it as a way to improve and enhance their health and wellbeing.

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Prediction of the sound field in large urban environments has been limited thus far by the heavy computational requirements of conventional numerical methods such as boundary element (BE), finite-difference time-domain (FDTD), or ray-tracing methods. Recently, a considerable amount of work has been devoted to developing energy-based methods for this application, and results have shown the potential to compete with conventional methods. However, these developments have been limited to two-dimensional (2-D) studies (along street axes), and no real description of the phenomena at issue has been exposed (e.g., diffraction effects on the predictions). The main objectives of the present work were (i) to evaluate the feasibility of an energy-based method, the diffusion model (DM), for sound-field predictions in large, 3-D complex urban environments, (ii) to propose a numerical hybrid method that could improve the accuracy and computational time of these predictions, and (iii) to verify the proposed hybrid method against conventional numerical methods. The proposed numerical hybrid method consists of a full-wave model coupled with an energy-based model. The full-wave model is used for predicting sound propagation (i) near the source, where constructive and destructive interactions between waves are substantial, and (ii) outside the cluttered environment, where free-field-like conditions apply. The energy-based model is used in regions where diffusion conditions are met. The hybrid approach, as implemented in this work, is a combination of FDTD and DM models. Results from this work show the role played by diffraction near buildings edges close to the source and near the exterior boundaries of the computational domain, and its impact on the predictions. A wrong modeling of the diffraction effects in the environment leads to significant under or overpredictions of the sound levels in some regions, as compared to conventional numerical methods (in these regions, some differences are as high as 10 dB). The implementation of the hybrid method, verified against a full FDTD model, shows a significant improvement of the predictions. The mean error thus obtained inside the cluttered region of the environment is 1.5 dB. / Master of Science

Στην παρούσα εργασία περιγράφεται μια νέα προσέγγιση στο πρόβλημα του εντοπισμού θέσης πολλαπλών πηγών στα ασύρματα δίκτυα αισθητήρων. Ο αλγόριθμος που προτείνεται βασίζεται σε μια εναλλακτική ερμηνεία της πληροφορίας που παρέχεται από το δίκτυο (υπό τη μορφή της λαμβανόμενης ισχύος του σήματος από κάθε κόμβο- αισθητήρα). Στα πλαίσια της εργασίας διεξάχθηκαν εκτενή πειράματα για την αξιολόγηση της μεθόδου όσον αφορά στην απόδοση, συναρτήσει διαφόρων παραμέτρων του προβλήματος. / This work describes a new approach to the energy-based multiple source localization problem in wireless sensor networks. The algorithm that is proposed in the present work is based on a alternative interpretation of the information that is provided by the network (under the form of received signal strength in each sensor-node). Extensive simulations have been conducted to characterize the performance of this method under various parameters.

Different key performance indicators are used to assess various aspects of a wind turbine (performance, reliability, financial aspects…). Availability metrics mainly, time-based and energy-based availability are the main indicators used to monitor and evaluate turbine’s availability performance today. However, due to significant growth of the share of energy sold into the electricity market as well as different selling structures, a new indicator has been established in order to assess availability performance in terms of revenues rather than time or energy.  This thesis compares energy and revenue-based availabilities of two turbines during 12 months of operational production. A methodology of calculation is suggested based on the International Electrotechnical Commission (IEC) information model for availability calculation. Time-based availability is calculated first, followed by energy-based, and finally revenue-based availability is derived from revenues as a result of combining energy production and electricity prices and revenue losses from energy losses and electricity prices. Availability metrics are calculated for three different scenarios, pure-market, mix of market and fixed price purchase agreement (PPA), and finally a PPA with a minimum monthly baseload to simulate the impact of volume risk. Results indicate a significant impact caused by the electricity price as well as the specifics of the selling agreement on revenue-based availability. Finding that in such cases, a significant divergence between energy and revenue-based indicators is possible. Limitations associated with the suggested methodology and case studies are presented and discussed.

L’évaluation du risque liée à l’utilisation des pesticides pour les invertébrés du sol est aujourd’hui réalisée à l’aide de l’espèce modèle E. fetida via l’utilisation de tests ecotoxicologiques standardisés (ISO et OCDE) sur la mortalité ou la reproduction. Ces deux points mériteraient d’être révisés puisque (i) l’espèce modèle est rarement présente dans les agroécosystèmes où les pesticides sont majoritairement utilisés, (ii) les tests réalisés sont peu réalistes et leur analyse statistique de type ad hoc ne permet aucune extrapolation dans le temps ou à des niveaux d’organisation supérieurs. Ainsi, une nouvelle espèce modèle a été proposée: Aporrectodea caliginosa. De plus, dans l’objectif d’analyser les effets ecotoxicologiques des pesticides sur cette espèce, un modèle bioénergétique a été proposé et calibré. Ensuite, les effets écotoxicologiques de deux formulations commerciales de pesticide, couramment utilisées en Europe, ont été évalués sur l’ensemble du cycle de vie (mortalité, comportement, reproduction, croissance). Les données de croissance ont été analysées à l’aide du modèle bioénergétique couplé à un modèle toxicocinétique. Ces analyses ont apporté une compréhension mécanistique des effets et ont permis l’estimation de valeurs seuils (les concentrations sans effet, CSE), indépendantes du temps d’exposition. Enfin, dans un objectif d’évaluation intégrée de l’usage des pesticides, il a été mis en évidence que la présence des vers de terre atténuait les effets des pesticides sur les communautés microbiennes des sols, responsables de la dégradation de la matière organique. L’ensemble des résultats pourra être utilisé, au-delà de la thèse, pour calibrer un modèle de dynamique des populations spatialisé de type individu centré (IBM). Ce type de modèle pourra être utilisé en évaluation du risque, pratiquée par les industriels et les agences d’évaluation. / Pesticide risk assessment for soil invertebrates is currently performed using the earthworm model species Eisenia fetida through the use of standardized ecotoxicological tests (ISO and OECD) on mortality or reproduction. These two points should be revised since (i) the model species is rarely found in agroecosystems where pesticides are used, (ii) the tests performed are unrealistic and their statistical analysis does not allow any extrapolation in time or at higher organizational levels (population). Thus, after a thorough reading of the literature, a new model species has been proposed: Aporrectodea caliginosa. In addition, in order to analyze the ecotoxicological effects of pesticides on this species, an energy-based model has been calibrated. Then, the ecotoxicological impacts of two commercial pesticide formulations, commonly used in Europe, were assessed on the entire life cycle (mortality, behavior, reproduction, growth). The growth data were analyzed with the energy-based model coupled with a toxicokinetic model. These analyzes provided a mechanistic understanding of the effects and the estimation of non-time-dependent threshold values (The no effect concentrations, NEC). Finally, for the purpose of an integrated pesticide risk assessment, it has been demonstrated that earthworms mitigate pesticide effects on soil microbial activity, involved in the soil organic matter degradation. All of the results are intended to be used, beyond the thesis, for the calibration of a spatialized population dynamics model with an Individual-based model approach (IBM). This model could be use in risk assessment, as performed by industrials and risk-assessment agencies.

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