Validation of the CFD code NEPTUNE for a full scale simulator for decay heat removal systems with in-pool heat exchangers

In the present work, a multi physics simulation of an innovative safety system for light water nuclear reactor is performed, with the aim to increase the reliability of its main decay heat removal system. The system studied, denoted by the acronym PERSEO (in Pool Energy Removal System for Emergency Operation) is able to remove the decay power from the primary side of the light water nuclear reactor through a heat suppression pool. The experimental facility, located at SIET laboratories (PIACENZA), is an evolution of the Thermal Valve concept where the triggering valve is installed liquid side, on a line connecting two pools at the bottom. During the normal operation, the valve is closed, while in emergency conditions it opens, the heat exchanger is flooded with consequent heat transfer from the primary side to the pool side. In order to verify the correct system behavior during long term accidental transient, two main experimental PERSEO tests are analyzed. For this purpose, a coupling between the mono dimensional system code CATHARE, which reproduces the system scale behavior, with a three-dimensional CFD code NEPTUNE CFD, allowing a full investigation of the pools and the injector, is implemented. The coupling between the two codes is realized through the boundary conditions. In a first analysis, the facility is simulated by the system code CATHARE V2.5 to validate the results with the experimental data. The comparison of the numerical results obtained shows a different void distribution during the boiling conditions inside the heat suppression pool for the two cases of single nodalization and three volume nodalization scheme of the pool. Finaly, to improve the investigation capability of the void distribution inside the pool and the temperature stratification phenomena below the injector, a two and three dimensional CFD models with a simplified geometry of the system are adopted.

Interacting fermionic atoms in optical lattices - A quantum simulator for condensed matter physics

This thesis reports on the creation and analysis of many-body states of interacting fermionic atoms in optical lattices. The realized system can be described by the Fermi-Hubbard hamiltonian, which is an important model for correlated electrons in modern condensed matter physics. In this way, ultra-cold atoms can be utilized as a quantum simulator to study solid state phenomena. The use of a Feshbach resonance in combination with a blue-detuned optical lattice and a red-detuned dipole trap enables an independent control over all relevant parameters in the many-body hamiltonian. By measuring the in-situ density distribution and doublon fraction it has been possible to identify both metallic and insulating phases in the repulsive Hubbard model, including the experimental observation of the fermionic Mott insulator. In the attractive case, the appearance of strong correlations has been detected via an anomalous expansion of the cloud that is caused by the formation of non-condensed pairs. By monitoring the in-situ density distribution of initially localized atoms during the free expansion in a homogeneous optical lattice, a strong influence of interactions on the out-of-equilibrium dynamics within the Hubbard model has been found. The reported experiments pave the way for future studies on magnetic order and fermionic superfluidity in a clean and well-controlled experimental system.

Ubuntu phone - un sistema operativo convergente per desktop e cellulari

Ubuntu Touch �� un nuovo sistema operativo per Desktop e Cellulari che nasce dalla necessit�� di unire sistemi eterogenei sotto un'unica piattaforma. L'infrastruttura di Touch, che garantisce convergenza fra dispositivi diversi, �� basata sull'innovativo server grafico Mir e sull'interfaccia grafica Unity. L'Application Model �� notevolmente migliorato, le applicazioni sono confinate attraverso AppArmor, e scambiano fra loro contenuti tramite il servizio Content-Hub. I tool di sviluppo supportati sono le tecnologie web (HTML5 e JavaScript) e C++ su Framework Qt (possibilit�� di utilizzare QML). Gli aggiornamenti di sistema, del core, sono sia parziali, attraverso archivi "delta" che introducono solo i cambiamenti necessari, sia full, sovrascrivono l'intero dispositivo. Lo sviluppo in Ubuntu SDK �� veloce e agile. Notevole la gestione degli emulatori, ma pecca di alcune feature tutt'ora mancanti. Gli Scope sono application content indipendent, vera innovazione in Ubuntu. Per sperimentare questa tecnologia si sviluppa uno scope per la ricerca di libri nella Biblioteca Gian Paolo Dore della Facolt�� di Ingegneria di Bologna.

Analysis of aircraft load spectrum by means of flight simulator

Damage tolerance analysis is a quite new methodology based on prescribed inspections. The load spectra used to derive results of these analysis strongly influence the final defined inspections programs that for this reason must be as much as possible representative of load acting on the considered structural component and at the same time, obtained reducing both cost and time. The principal purpose of our work is in improving the actual condition developing a complete numerical Damage Tolerance analysis, able to prescribe inspection programs on typical aircraft critical components, respecting DT regulations, starting from much more specific load spectrum then those actually used today. In particular, these more specific load spectrum to design against fatigue have been obtained through an appositively derived flight simulator developed in a Matlab/Simulink environment. This dynamic model has been designed so that it can be used to simulate typical missions performing manually (joystick inputs) or completely automatic (reference trajectory need to be provided) flights. Once these flights have been simulated, model���s outputs are used to generate load spectrum that are then processed to get information (peaks, valleys) to perform statistical and/or comparison consideration with other load spectrum. However, also much more useful information (loads amplitude) have been extracted from these generated load spectrum to perform the previously mentioned predictions (Rainflow counting method is applied for this purpose). The entire developed methodology works in a complete automatic way, so that, once some specified input parameters have been introduced and different typical flights have been simulated both, manually or automatically, it is able to relate the effects of these simulated flights with the reduction of residual strength of the considered component.

Design and implementation of the ESEO spacecraft simulator

The thesis work is developed under the European Student Earth Orbiter (ESEO) project supported by the European Space Agency (ESA) in order to help prepare a well-qualified space-engineering workforce for Europe's future. In the following chapters we are going to analyse how to simulate some ESEO subsystem. First of all, the Thermal Subsystem that evaluates the temperature evolution of on-board instruments. For this purpose, simulating also the orbital and attitude dynamics of the spacecraft, it is necessary in order to evaluate external environmental fluxes. The Power Subsystem will be the following step and it models the ability of a spacecraft to produce and store electrical energy. Finally, we will integrate in our software a block capable of simulating the communication link between the satellite and the Ground Station (GS). This last step is designed and validated during the thesis preparation.

Evoluzione delle user interface: dalla metafora del desktop al Wearable Computing

Negli ultimi decenni abbiamo assistito ad una graduale evoluzione delle interfacce utente e della tecnologia. Sono stati introdotti nuovi dispositivi mobile e wearable che negli ultimi anni hanno subito un incremento tecnologico esponenziale arrivando a fondersi con la vita di tutti i giorni. Le classiche interfacce grafiche WIMP, la metafora del desktop e le linee guida di progettazione fino ad ora sviluppate non risultano ideali per la nuova tecnologia di wearable computing. Il proposito che la tesi vuole andare ad affrontare �� proprio quello di indagare lo sviluppo di nuove user inteface basate sulla tecnologia wearable ed in particolare per smart glasses.

Design, implementation and performance evaluation of an anonymous distributed simulator

La simulazione �� definita come la rappresentazione del comportamento di un sistema o di un processo per mezzo del funzionamento di un altro o, alternativamente, dall'etimologia del verbo ���simulare���, come la riproduzione di qualcosa di fittizio, irreale, come se in realt��, lo fosse. La simulazione ci permette di modellare la realt�� ed esplorare soluzioni differenti e valutare sistemi che non possono essere realizzati per varie ragioni e, inoltre, effettuare differenti valutazioni, dinamiche per quanto concerne la variabilit�� delle condizioni. I modelli di simulazione possono raggiungere un grado di espressivit�� estremamente elevato, difficilmente un solo calcolatore potr�� soddisfare in tempi accettabili i risultati attesi. Una possibile soluzione, viste le tendenze tecnologiche dei nostri giorni, �� incrementare la capacit�� computazionale tramite un���architettura distribuita (sfruttando, ad esempio, le possibilit�� offerte dal cloud computing). Questa tesi si concentrer�� su questo ambito, correlandolo ad un altro argomento che sta guadagnando, giorno dopo giorno, sempre pi�� rilevanza: l���anonimato online. I recenti fatti di cronaca hanno dimostrato quanto una rete pubblica, intrinsecamente insicura come l���attuale Internet, non sia adatta a mantenere il rispetto di confidenzialit��, integrit�� ed, in alcuni, disponibilit�� degli asset da noi utilizzati: nell���ambito della distribuzione di risorse computazionali interagenti tra loro, non possiamo ignorare i concreti e molteplici rischi; in alcuni sensibili contesti di simulazione (e.g., simulazione militare, ricerca scientifica, etc.) non possiamo permetterci la diffusione non controllata dei nostri dati o, ancor peggio, la possibilit�� di subire un attacco alla disponibilit�� delle risorse coinvolte. Essere anonimi implica un aspetto estremamente rilevante: essere meno attaccabili, in quanto non identificabili.

Quality of resuscitation: flight attendants in an airplane simulator use a new mechanical resuscitation device--a randomized simulation study

Cardiopulmonary resuscitation (CPR) during flight is challenging and has to be sustained for long periods. In this setting a mechanical-resuscitation-device (MRD) might improve performance. In this study we compared the quality of resuscitation of trained flight attendants practicing either standard basic life support (BLS) or using a MRD in a cabin-simulator.

Concurrent and predictive validation of a novel robotic surgery simulator: a prospective, randomized study

We evaluated the concurrent and predictive validity of a novel robotic surgery simulator in a prospective, randomized study.

Face, content and construct validity of a novel robotic surgery simulator

We evaluated the face, content and construct validity of the novel da Vinci�� Skills Simulator��� using the da Vinci Si��� Surgeon Console as the surgeon interface.