Τα ολοκληρωμένα ηλιακά συστήματα συλλέκτη αποθήκης αποτελούνται από μία δεξαμενή αποθήκευσης, της οποίας τμήμα της επιφάνειας της χρησιμοποιείται σαν ηλιακός συλλέκτης. Συνήθως το ρευστό της αποθήκης είναι το νερό χρήσης. Στο υπό εξέταση σύστημα το νερό χρήσης θερμαίνεται έμμεσα, διερχόμενο μέσα από σωληνώσεις εναλλάκτη θερμότητας που τοποθετείται στο εσωτερικό της παραλληλεπίπεδης δεξαμενής. Για την εντατικοποίηση της μετάδοσης θερμότητας προς το νερό χρήσης, δημιουργείται ανάδευση του ρευστού του δοχείου μέσω κυκλοφορητή, ο οποίος τίθεται σε λειτουργία μόνο όταν υπάρχει ζήτηση ζεστού νερού. Προς αποφυγή παραμορφώσεων τοποθετούνται πτερύγια συγκράτησης που ενώνουν τις δύο μεγάλες επιφάνειες της δεξαμενής. Στην παρούσα διδακτορική διατριβή διερευνήθηκαν τα ροϊκά φαινόμενα στο εσωτερικό του ICS που έχει περιγραφεί προηγουμένως, με στόχο τη μεγιστοποίηση της θερμανταλλαγής μεταξύ των δύο κυκλωμάτων νερού. Για την παρατήρηση του ροϊκού πεδίου καθώς και την λήψη μετρήσεων ταχυτήτων κατασκευάστηκε πειραματική συσκευή με διαφανή τοιχώματα από Plexiglas. Ελήφθησαν μετρήσεις ταχυτήτων και διακυμάνσεων με χρήση συστήματος Laser Doppler διπλής ακτίνας. Για την οπτικοποίηση του ροϊκού πεδίου τοποθετήθηκαν σωματίδια πολυστερίνης στο εσωτερικό της συσκευής. Ελήφθησαν ψηφιακές φωτογραφίες και βιντεοσκοπήσεις του ροϊκού πεδίου. Για την υπολογιστική προσομοίωση χρησιμοποιήθηκε το εμπορικό λογισμικό FLUENT. Αναπτύχθηκε υπολογιστικό μοντέλο και επιλύθηκε με όλα τα διαθέσιμα μοντέλα τύρβης. Στη συνέχεια πραγματοποιήθηκε σειρά υπολογιστικών προσομοιώσεων, στις οποίες διερευνήθηκε η βέλτιστη θέση και το μέγεθος των στομίων ανακυκλοφορίας, η βέλτιστη διάταξη των πτερυγίων συγκράτησης και η βέλτιστη θέση του εναλλάκτη. Επιπλέον προσδιορίστηκε υπολογιστικά και πειραματικά ο χρόνος αποκατάστασης του ροϊκού πεδίου. Τέλος, τα αποτελέσματα συγκρίθηκαν και με πειραματικά αποτελέσματα άλλων εργασιών. Τα συμπεράσματα που εξάγονται έχουν ως ακολούθως: Το μοντέλο τύρβης standard k-ω δίνει τα πιο αξιόπιστα αποτελέσματα. Το υπολογιστικό μοντέλο θεωρείται πιστοποιημένο μετά από πειραματική επιβεβαίωση ταχυτήτων και θερμοκρασιών. Το στόμιο ανακυκλοφορίας δεν πρέπει να τοποθετείται κάθετα στις μεγάλες επιφάνειες της δεξαμενής, ενώ η διάμετρος του πρέπει να είναι 1/2" ή και μικρότερη. Ο χρόνος αποκατάστασης του ροϊκού πεδίου είναι περίπου 35 s. Τα πτερύγια συγκράτησης πρέπει να ακολουθούν τις ροικές γραμμές. Ως βέλτιστη θέση του εναλλάκτη θεωρείται όταν τοποθετείται σε επαφή με το τοίχωμα. / Integrated Collector Storage (ICS) solar systems use part of the hot water storage as collector, i.e. half of the storage surface is used as absorber. Usually, the storage medium serves also as the energy transfer medium (service hot water). In the examined ICS, the service water is heated indirectly, passing through a serpentine heat exchanger placed inside the tank. The heat transfer from the stored water to the service water is intensified by the agitation of the stored water. A simple solution is the recirculation of the stored water by a small pump, which is functioning whenever a request for hot water exists. Fins in suitable positions, connect the front and back surface of the ICS, to withstand the deformation due to pressures by the tank water. In the present PhD thesis, the flow phenomena inside the ICS previous mentioned, are investigated. The aim is the maximization of the heat transfer between the two water circuits. An experimental device was constructed by transparent Plexiglas, for flow visualization and velocity measurements. A dual beam Laser Doppler Velocimetry (LDV) system was used to measure velocities. Polystyrene particles were added in the comprised water, for the visualization of the path lines. Photographs and video films were also taken. The commercial code FLUENT is used for the Computational Fluid Dynamics (CFD) simulations. A CFD model is developed and solutions are obtained using all the available turbulence models. Three main factors that influence the performance are optimized: the position and size of the recirculation ports, the arrangement and size of the interconnecting fins and the heat exchanger placement. The settling time, i.e., the time required for the flow field to be fully developed, is computed both numerically and experimentally. The previous analysis leads to the following conclusions: The standard k–ω model is selected as the most appropriate. The model is validated, with good agreement, against experimental measurements of velocities and temperatures. The placement of the inlet recirculation port perpendicular to the main surfaces of the ICS should be avoided, while its diameter should be 1/2" or less. The settling time is computed about 35s. The interconnecting fins, of the two main ICS surfaces should follow the flow filed path lines. The optimal placement of the tube heat exchanger is in contact with the two major surfaces of the storage tank.

Cette thèse s’inscrit dans le domaine de la localisation de défauts de type «soft» dans les Circuits Intégrés (CI) analogiques et mixtes à l’aide des techniques dynamiques de stimulation laser en faible perturbation. Les résultats obtenus à l’aide de ces techniques sont très complexes à analyser dans le cas des CI analogiques et mixtes. Ce travail porte ainsi particulièrement sur le développement d’une méthodologie facilitant l’analyse des cartographies laser. Cette méthodologie est basée sur la comparaison de résultats de simulations électriques de l’interaction faisceau laser-CI avec des résultats expérimentaux (cartographies laser). L’influence des phénomènes thermique et photoélectrique sur les CI (niveau transistor) a été modélisée et simulée. La méthodologie a été validée tout d’abord sur des structures de tests simples avant d’être utilisée sur des CI complexes que l’on trouve dans le commerce. / This thesis deals with Soft failure localization in the analog and mixed mode Integrated Circuits (ICs) by means of Dynamic Laser Stimulation techniques (DLS). The results obtained using these techniques are very complex to analyze in the case of analog and mixed ICs. In this work we develop a methodology which facilitates the analysis of the laser mapping. This methodology consists on combining the experimental results (laser mapping) with the electrical simulations of laser stimulation impact on the device. The influence of photoelectric and thermal phenomena on the IC (transistor level) has been modeled and simulated. The methodology has been validated primarily on test structures before being used on complex Freescale ICs existing in commerce.

We begin with a short analysis of the history of Investor-State Dispute Settlement (ISDS). We then discuss the merits and demerits of the regime, such as the arguments between finality, speediness, and correctness. Following from this, historical reforms are discussed, and whether those issues have gotten worse or better since these discussions. The modern problems are discussed, leading to the explanation of the “legitimacy crisis”. As Appellate Mechanisms (AM) and Investment Court Systems (ICS) both propose multi layered systems, we argue whether ISDS must be a “one bite at the apple” system. We expand on the issues of regulatory chill, before showing the contradictions in the granting of awards. From this, a discussion is raised on the advantages of a tenured system of adjudicators, particularly in reference to their apparent bias. We delve deeper into the direct consequences of the perceived issues of ISDS, in the context of human rights, the environment, and other issues of sovereignty.As more reforms are suggested, the question of “what makes arbitration, arbitration?” is raised. From here, we may begin to suggest reforms based on which key factors are to be preserved. Firstly, we discuss current reform options, such as the Mauritius Convention. We take inspiration from existing AM, and prior discussions on the implementation of such a system across the International Centre for Settlement of Investment Disputes (ICSID) and United Nations Commission on International Trade Law (UNCITRAL) frameworks. We analyse whether these discussions have led to change by comparing trends in drafting.Thereon, we offer suggestions of reform. ICS and how this would be implemented, what it would look like structurally, and its positive and negative effects. Using the Comprehensive Economic and Trade Agreement (CETA) and other contemporary ICS reform suggestions, we gain some knowledge of what an ICS regime could and should look like, the implementation of AM previously discussed in this regime, and other. Finally, we offer a different solution to the problems, yet less pragmatic, the termination of arbitration.

This Master’s Thesis is dealing with measuring antennas in far field. Especially with automation this measure, direction sensors made by optical mouse, Integrated Hall ICs for Linear and Off-Axis Rotary Motion Detection and remote unit this workplace, which can made communication with PC by USB. It describes the making control program for the PC.

<p>Modern reactors promise enhanced capabilities not previously possible including integration with the smart grid, remote monitoring, reduced operation and maintenance costs, and more efficient operation. . Modern reactors are designed for installation to remote areas and integration to the electric smart grid, which would require the need for secure undisturbed remote control and the implementation of two-way communications and advanced digital technologies. However, two-way communications between the reactor facility, the enterprise network and the grid would require continuous operation data transmission. This would necessitate a deep understanding of cybersecurity and the development of a robust cybersecurity management plan in all reactor communication networks. Currently, there is a limited number of testbeds, mostly virtual, to perform cybersecurity research and investigate and demonstrate cybersecurity implementations in a nuclear environment. To fill this gap, the goal of this thesis is the development of a real-time cyber-physical testbed with real operational and information technology data to allow for cybersecurity research in a representative nuclear environment. In this thesis, a prototypic cyber-physical testbed was designed, built, tested, and installed in PUR-1. The cyber-physical testbed consists of an Auxiliary Moderator Displacement Rod (AMDR) that experimentally simulates a regulating rod, several sensors, and digital controllers mirroring Purdue University Reactor One (PUR-1) operation. The cyber-physical testbed is monitored and controlled remotely from the Remote Monitoring and Simulation Station (RMSS), located in another building with no line of sight to the reactor room. The design, construction and testing of the cyber-physical testbed are presented along with its capabilities and limitations. The cyber-physical testbed network architecture enables the performance of simulated cyberattacks including false data injection and denial of service. Utilizing the RMSS setup, collected information from the cyber-physical testbed is compared with real-time operational PUR-1 data in order to evaluate system response under simulated cyber events. Furthermore, a physics-based model is developed and benchmarked to simulate physical phenomena in PUR-1 reactor pool and provide information about reactor parameters that cannot be collected from reactor instrumentation system.</p>

Ultraprecision single point diamond turning is required to produce parts with sub-nanometer surface roughness and sub-micrometer surface profiles tolerances. These parts have applications in the optics industry, where tight form accuracy is required while achieving high surface finish quality. Generally, parts can be polished to achieve the desired finish, but then the form accuracy can easily be lost in the process rendering the part unusable. Currently, most mid to low spatial frequency surface finish errors are inspected offline. This is done by physically removing the workpiece from the machining fixture and mounting the part in a laser interferometer. This action introduces errors in itself through minute differences in the support conditions of the over constrained part on a machine as compared to the mounting conditions used for part measurement. Once removed, the fixture induced stresses and the part’s internal residual stresses relax and change the shape of the generally thin parts machined in these applications. Thereby, the offline inspection provides an erroneous description of the performance of the machine. This research explores the use of a single, high resolution, capacitance sensor to quickly and qualitatively measure the low to mid spatial frequencies on the workpiece surface, while it is mounted in a fixture on a standard ultraprecision single point diamond turning machine after a standard facing operation. Following initial testing, a strong qualitative correlation exists between the surface profiling on a standard offline system and this online measuring system. Despite environmental effects and the effects of the machine on the measurement system, the capacitive system with some modifications and awareness of its measurement method is a viable option for measuring mid to low spatial frequencies on a workpiece surface mounted on an ultraprecision machine with a resolution of 1nm with an error band of ±5nm with a 20kHz bandwidth. / Thesis / Master of Applied Science (MASc)