Μελέτη των καθιζήσεων λόγω διάνοιξης δίδυμης σήραγγας μετρό Θεσσαλονίκης στο τμήμα Αγία Σοφία-Πανεπιστήμιο

312 σ.Εθνικό Μετσόβιο Πολυτεχνείο--Μεταπτυχιακή Εργασία. Διεπιστημονικό-Διατμηματικό Πρόγραμμα Μεταπτυχιακών Σπουδών (Δ.Π.Μ.Σ.) "Σχεδιασμός & Κατασκευή Υπόγειων Έργων"Στην παρούσα μεταπτυχιακή διατριβή πραγματοποιείται ανάστροφη ανάλυση των παρατηρούμνενων επιφανειακών καθιζήσεων οι οποίες τελέστηκαν λόγω της μηχανοποιημένης όρυξης δίδυμης σήραγγας του μετρό Θεσσαλονίκης με μηχάνημα εξισσορόπησης εδαφικών πιέσεων, στο υποτμήμα 3 το οποίο ευρίσκεται μεταξύ των σταθμών Αγία Σοφία και Πανεπιστήμιο. Η ανάστροφη ανάλυση στοχεύει στην περιγραφή του προφίλ των καθιζήσεων μέσω γκαουσσιανών καμπύλων βέλτιστης προσαρμογής με χρησιμοποίηση των εμπειρικών σχέσεων. Πραγματοποιείται προσομοιώση με εφαρμογή αριθμητικών μεθόδων, περιοχής του υπο μελέτη τμήματοςAt the present master thesis work, a back anslysis of the observed tunnel induced surface settlements at the subdivision 3 of the Thessaloniki Metro which is situated between Agia Sofia Station and Panepistimio Station is conducted. Construction of the twin tunnel is made by means of two Earth Pressure Balance boring machines. The back analysis carried out, aims to generate best fit gaussian curves that describe the in situ settlement profiles. The location where maximum settlements were measured is modeled, using Numerical Analysis Methods.Αθανάσιος Π. Δημακόπουλο

2D Coupled CFD model of and Oscillating Water Column using PROTEUS

This is the author accepted manuscript. The final version is available from ASRANet via the link in this recordFloating Oscillating Water Columns (OWC) are one of many potential Renewable Energy Devices under consideration as part of the global drive towards clean energy sources. In order to reach deployment, these devices first exist in the form of computational models. These models allow the devices to be tested under a range of conditions and mooring configurations. However, the design of systems often fails to account for the moorings at an early stage, which can result in disappointing performance at later stages of design and deployment. In this study, Proteus is used to produce a 2D model of an OWC that demonstrates its effectiveness as a tool for modelling floating marine structures. The model solves the Reynolds Averaged Navier Stokes equations in the fluid domain, using a Volume of Fluid-Level Set approach for defining the air-water interface. Proteus is coupled with the Chrono library to solve the rigid body motions, and the response of the mooring lines. The model is validated against both experimental and other computational models. The effect of a mooring system is shown on the water column response. This study provides a launch pad for more complex studies. Proteus has 3D modelling capabilities, and as a result, 3D OWC, other wave energy devices and floating wind turbines are all potential devices that Proteus has the capability to recreate in high fidelity models.ERDCHR WallingfordEnergy Technologies Institute (ETI)Engineering and Physical Sciences Research Council (EPSRC

The cooperative parallel: A discussion about run-time schedulers for nested parallelism

Nested parallelism is a well-known parallelization strategy to exploit irregular parallelism in HPC applications. This strategy also fits in critical real-time embedded systems, composed of a set of concurrent functionalities. In this case, nested parallelism can be used to further exploit the parallelism of each functionality. However, current run-time implementations of nested parallelism can produce inefficiencies and load imbalance. Moreover, in critical real-time embedded systems, it may lead to incorrect executions due to, for instance, a work non-conserving scheduler. In both cases, the reason is that the teams of OpenMP threads are a black-box for the scheduler, i.e., the scheduler that assigns OpenMP threads and tasks to the set of available computing resources is agnostic to the internal execution of each team. This paper proposes a new run-time scheduler that considers dynamic information of the OpenMP threads and tasks running within several concurrent teams, i.e., concurrent parallel regions. This information may include the existence of OpenMP threads waiting in a barrier and the priority of tasks ready to execute. By making the concurrent parallel regions to cooperate, the shared computing resources can be better controlled and a work conserving and priority driven scheduler can be guaranteed.Peer ReviewedPostprint (author's final draft

Does fixed-angle plate osteosynthesis solve the problems of a fractured proximal humerus?: A prospective series of 87 patients

Background and purpose There is considerable controversy about the treatment of complex, displaced proximal humeral fractures. Various types of head-preserving osteosynthesis have been suggested. This prospective case series was designed to evaluate the perioperative and early postoperative complications associated with fixed-angle implants and to record outcome after bone healing

Advanced numerical modelling of wave structure interaction

This book will serve as a reference guide, and state-of-the-art review, for the wide spectrum of numerical models and computational techniques available to solve some of the most challenging problems in coastal engineering. The topics covered in this book, are explained fundamentally from a numerical perspective and also include practical examples applications. Important classic themes such as wave generation, propagation and breaking, turbulence modelling and sediment transport are complemented by hot topics such as fluid and structure interaction or multi-body interaction to provide an integral overview on numerical techniques for coastal engineering. Through the vision of 10 high impact authors, each an expert in one or more of the fields included in this work, the chapters offer a broad perspective providing several different approaches, which the readers can compare critically to select the most suitable for their needs. Advanced Numerical Modelling of Wave Structure Interaction will be useful for a wide audience, including PhD students, research scientists, numerical model developers and coastal engineering consultants alike

Universal correlations used in solar application and their evaluation in the Athens area

150 σ.Η εργασία αυτή εμπεριέχει τις πιο γνωστές σχέσεις υπολογισμού ηλιακών μεγεθών και όταν τα πειραματικά δεδομένα επαρκούν συγκρίνει τα εξαγόμενα των σχέσεων αυτών με τις πραγματικές τιμές στη περιοχή των Αθηνών. Προτείνονται επίσης νέες σχέσεις από τον συγγραφέα που προσεγγίζουν τισ πραγματικές τιμές της ηλιακής ακτινοβολίας στην Αθήνα.Universal Correlations Used in Solar Application and their Evaluation in the Athens Area.Ιωάννης Π. Δημακόπουλο