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Data-driven Model Predictive Control for Lean NOx Trap Regeneration
No full textLean NOx Trap (LNT) is one of the most eective after-treatment technologies used to reduce NOx emissions of diesel engines. One relevant problem in this context is LNT regeneration timing control. This problem is indeed difficult due to the fact that LNTs are highly nonlinear systems, involving complex physical/chemical processes that are hard to model. In this paper, a novel data-driven model predictive control (D2-MPC) approach for regeneration timing of LNTs is proposed, allowing us to overcome these issues. This approach does not require a physical model of the engine/trap system but is based on low-complexity polynomial prediction model, directly identied from data. The regeneration timing is computed through an optimization algorithm, which uses the identied model to predict the LNT behavior. The proposed D2- MPC approach is tested in a co-simulation study, where the plant is represented by a detailed LNT model, developed using the well-known commercial tool AMEsim, and the controller is implemented in Matlab/Simulink
A flexible and portable powerpack by solid-state supercapacitor and dye-sensitized solar cell integration
No full textThe recent need to benefit from electricity in every moment of daily life, particularly when the access to the electric grid is limited, is forcing the scientific and industrial community to an intensive effort towards the production of integrated energy harvesting and storage devices able to drive low power electronics. In this framework, flexibility represents a mandatory requirement to cover non-planar or bendable surfaces, more and more common in nowadays-electronic devices. To this purpose, here we present an innovative device consisting of a TiO2 nanotube-based dye sensitized solar cell and a graphene-based electrical double layer capacitor integrated in a flexible architecture. Both the units are obtained by easily scalable fabrication processes exploiting photopolymer membranes as electrolytes and metal grids as current collectors. The performance of the two units and of the integrated system are thoroughly investigated by electrochemical measurements also under different irradiation conditions. To the best of our knowledge, this work shows the highest energy conversion and storage efficiency (1.02%) ever attained under 1 Sun irradiation condition for a flexible dye-sensitized-based non-wired photocapacitor. Noteworthy, this value dramatically increases while lowering the illumination condition to 0.3 Sun, achieving a remarkable value of 1.46%, thus showing optimal performances in real operation conditions
ANALYSIS AND MODULATION OF MOLECULAR QUANTUM-DOT CELLULAR AUTOMATA (QCA) DEVICES
No full textField-Coupled nanocomputing (FCN) paradigms offer fundamentally new approaches for digital computing without involving current transistors. Such paradigms perform computations using local field interactions between nanoscale building blocks which are organized with purposes. Among several FCN paradigms currently under active investigation, the Molecular Quantum-dot Cellular Automata (MQCA) is found to be the most promising and its unique features make it attractive as a candidate for post-CMOS nanocomputing. MQCA is based on electrostatic interactions among quantum cells with nanometer scale eliminating the need of charge transportation, hence its energy consumption is significantly decreased. Meanwhile it also possesses the potential of high throughput if efficient pipelining of information propagation is introduced. This could be realized adopting external clock signals which precisely control the adiabatic switching and direction of data flow in MQCA circuits. In this work, in order to model MQCA as electronic devices and analyze its information propagation with clock taken into account, an effective algorithm based on ab-initio simulations and modelling of molecular interactions has been applied in presence of a proposed clock mechanism for MQCA, including the binary wire, the wire bus and the majority voter. The quantitative results generated depict compelling clocked information propagation phenomena of MQCA devices and most importantly, provide crucial feedback for future MQCA experimental implementation
Reinforcement of the 18th Century Buttresses of Maniace Castle: Design and Execution
No full textManiace Castle, built on Ortygia island in Siracusa (Italy) in the first half of the 13th century and hosting a magnificent hypostyle hall (the Salone), a square area covered by 25 cross vaults supported by columns, was severely damaged by the 1693 earthquake and the explosion of the ammunition dump in 1704. The buttresses, built immediately afterward to counteract the thrust of the 10 surviving vaults, did not guarantee adequate seismic safety so that a metal scaffolding was installed in 2001 to prevent an overturning mechanism. This article discusses the design and execution of an external pre-stressing steel system to increase existing buttress strength and the seismic capacity of the Salone, starting with historical and constructional analyses and dealing with both analytical and technical aspects. The monitoring system installed to detect structural response during and after the working execution is shown, along with some of the data acquired so far
S&N-S Light: An anthropic noise control device to reduce the noise level in densely occupied spaces encouraging personal control of voice
No full textRecently, in many fields related to environmental quality, such as thermal and visual quality, the tendency is to customise the comfort according to the user's needs. A tailored comfort zone is planned in public spaces, in which occupants can set their own comfort level with passive or active systems. In this context, the reduction of noise due to anthropic sources can be seen as a priority. In densely occupied spaces, such as classrooms, workplaces, restaurants and outdoor spaces, the noise due to users chatting has a detrimental effect upon performance, health and environmental quality. This study reports applications of S&N-S Light, Speech & Noise Stop-Light, a patented smart phonometric device with a warning light activation of exceeding of predetermined anthropic sound levels limits, which encourages personal voice control through visual feedback. The light activation, with green, yellow and red colour, is based on an adaptive algorithm that accounts for pre-defined statistical noise levels; therefore accidental noise levels can be filtered. The device has been used in classrooms, restaurants and urban squares. Results indicate a decrease of noise levels with S&N-S Light, especially when the occupants received training about the device benefits
Space-time correlation of earthquakes and acoustic emission monitoring of historical constructions
No full textThis PhD thesis is primarily concerned with the evaluation of seismicity in regional areas in order to analyse the correlation between earthquakes and Acoustic Emissions (AE) detected by monitoring historical constructions. Acoustic emissions transmitted in materials and earthquakes in the Earth's crust are similar phenomena. Despite the fact that they take place at different scales, in both cases they involve a release of elastic energy from a source located in a medium: micro cracks in materials and earthquakes' hypocenters in the Earth's crust. Considering the similarity between the two phenomena and also that earthquakes may have precursors, i.e. phenomena of change in the Earth's physical conditions that take place prior to an earthquake, it was observed that acoustic emission can anticipate the occurrence of certain earthquakes. This is due to micro-cracking of the Earth's crust that anticipates the more properly catastrophic phenomenon. The research into these precursors was carried out through the analysis of correlation between acoustic emissions and seismic events. The monitoring sites, where this experimentation has been applied, are two important historical constructions of the Italian cultural heritage: the "Sacred Mountain of Varallo" in Piedmont region and the "Asinelli Tower" in Bologna, Emilia-Romagna region. The proposed statistical method of analysis is based on the Grassberger-Procaccia (GP) correlation integral. It gives the cumulative probability occurrence of couples of events, AE and seismic events, that occur in the same time windows nearby the monitored site. The analyses conducted for the historical constructions allowed us firstly to confirm the precursory behaviour of acoustic emissions and secondly to verify that between 24 hours and 10 minutes before the main shocks the highest density of acoustic emissions appears. In the second part of the PhD thesis the space correlation between only the earthquakes was studied, in particular those starting from the significant earthquake of the 6th April 2009, with its epicentre close to L'Aquila (Abruzzi region) in Italy, and those starting from the catastrophic and recent earthquake of the 24th August 2016, with its epicentre close to Amatrice (Lazio region), also in Italy. By using the b-value of the Gutenberg-Richter (GR) Law and the Gutenberg-Procaccia (GP) algorithm, the correlation between earthquakes in specific areas has been performed. The aim of the analyses was to recognize the seismic events itself as possible statistic precursory of significant earthquakes. Moreover, starting from the (GP) correlation integral the fractal distribution of events in space, Ds, was evaluated, finding the fault lines activated by the analysed seismic sequence. The analyses conducted for the L'Aquila seismic sequence allowed us to recognize precursory events in the months before the earthquake of April 2009; in fact in the months before April there was a continuous decrease of the b-value trend and of the fractal dimension of seismic events in space, Ds. A relation between the fractal dimension in space of the active fault system during seismic activity, Ds, and the b-value can be established considering the concepts of geometrical self-similarity. The applicability of a fractal relation implies that the seismicity is scale invariant over the range of applicability of the relation, therefore the Gutenberg-Richter relation for earthquakes defining the b-value is a fractal relation with Ds=2b. The analyses, b-value analysis and correlation integral, carried out separately allowed us to verify that Ds≅2b in the month of April 2009. In the case of the Amatrice seismic sequence, a sharp variation in the trend of b-value between July 2016 and August 2016 was recognized; the b-value changes quickly over a short time span. Therefore, in this case, a not so clear precursory behaviour can be noticed. Also in this case, the b-value analysis and the correlation integral, carried out separately, allowed us to verify that Ds≅2b in the month of August 2016. In conclusion, this PhD thesis allows us to evaluate whether there are statistical precursors of significant earthquakes by means of the b-value and the correlation analysis between seismic events, or between seismic events and acoustic emissions by monitoring of the historical constructions. This work represents a first step for the realization of a monitoring and analysis network to assess the behaviour of seismic sequences in order to understand if there are possible precursory events of significant earthquakes, as in the case of L'Aquila, and also to evaluate acoustic emission events as a precursory phenomenon useful for earthquake prediction. The improvement of seismic monitoring, together with structural consolidation and reinforcement, could lead to significant benefits for the mitigation of the devastating effects of earthquakes
Volte stellari e planteriane negli atri barocchi in Torino - Star-shaped and Planterian Vaults in Turin Baroque Atria
No full textLe volte stellari e planteriane costituiscono il sistema di copertura, realizzato in muratura laterizia, più diffuso negli atri di palazzi e case nobiliari torinesi fra gli ultimi decenni del Seicento e gli anni ottanta del Settecento. Si tratta di volte la cui immagine intradossale rivela la complessità geometrica di forme generate mediante la composizione di differenti superfici, finalizzata ad ottenere effetti di movimento e leggerezza, anche in casi di spazi contenuti. La varietà di conformazioni che queste volte presentano offre un interessante campo di sperimentazione per la formulazione di differenti ipotesi sulle geometrie a sostegno delle forme realizzate, verificabili attraverso operazioni di rilevamento intradossale, la cui restituzione si avvale proficuamente degli strumenti di modellazione digitale. | Made of brickwork masonry, Star-shaped and Planterian vaults constitute the more common covering system in buildings and noble houses of Turin between the end of the Seventeenth Century and the end of the Eighteenth Century. These are vaults whose intrados image reveals a geometric complexity of shapes - generated by the composition of different surfaces - that are aimed to get movement and lightness effects, even in case of small spaces. The conformations variety that characterises these vaults offers an interesting experimentation field for making hypotheses on the geometry that rules the realized shapes, verifiable through intrados survey operations, the representation of which is usefully allowed by digital modelling tools
Sguardi incrociati su un convento vittoniano. Santa Chiara a Torino
No full textEsempio paradigmatico di architettura conventuale di età moderna, il monastero di S. Chiara a Torino, ricostruito a partire dal 1742 dall'architetto torinese Bernardo Vittone, sembra sfidare qualsiasi tentativo univoco di lettura. Questo libro affronta il problema dell'interpretazione storica e critica dell'opera, attraverso i contributi di cinque autori portatori di metodi e obiettivi epistemologici differenti. La natura istituzionale e sociale dei conventi femminili, la dimensione negoziata del progetto e del programma, il peso dell'architetto-autore, le vicende materiali dell'opera anche al di fuori del suo sito attuale e le problematiche ambigue, ormai secolari, che si aprono con il suo restauro sono tra i temi indagati nei testi
