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Transducers and sensor-near signal processing for structural health monitoring of composite structures
No full textThis thesis delves into innovative transducer designs focused on directional sensing and acoustic wave generation, particularly through electrode patterning, for applications in Structural Health Monitoring (SHM). Ultrasonic Guided Waves (GWs), especially Lamb waves, have become widely used in SHM systems for plate-like structures due to their ability to travel long distances with minimal attenuation, while interacting with various types of defects, and convey information that can be detected by remote receiver. This unique property of GWs opens up possibilities for exploring their potential for transmitting information for inspection purposes.
The research aims to overcome limitations of current SHM systems, such as weight, complex circuitry, and maintenance concerns, by introducing novel piezoelectric transducers known as shaped transducers. These transducers, including Frequency Steerable Acoustic Transducers (FSATs), leverage electrode patterning to enhance directional capabilities without requiring extensive phase control or managing numerous channels. The thesis prototypes FSATs to operate in actuation mode for Piezoceramic substrates and introduces unidirectional FSATs to address wave propagation ambiguities observed in previous designs. The design is further improved by introducing a third generation of FSATs, significantly reducing side lobes in beam patterns and enhancing imaging resolution.
Expanding on the FSAT design, the thesis applies it to various SHM applications including acoustic data and power transmission, pipeline monitoring, and acoustic source localization. Discrete FSATs are developed for targeted transmission at multiple frequencies, while specialized designs facilitate helical wave generation for pipeline defect detection and wide-band acoustic emission monitoring for impact or defect growth detection. Additionally, an FSAT design tool is developed to streamline the design process for various transducer geometries
Assessing the current state of adiabatic quantum computers in solving challenging computational problems
Get PDFThe present Thesis aims to achieve three main objectives. The first is to present and comment the experimental results obtained during my PhD, which show that performances of modern AQCs are steadily improving thanks to both hardware and software advancements, and are getting close to practical utility.
The second objective is to provide the reader with an extensive literature review regarding the design, the use, the capabilities, and the possible applications of AQCs. Indeed, there is currently no document or book on AQCs that contains the comprehensive amount of commented and ordered references presented in this Thesis. Thus, I hope this work can serve as an introductory compendium to a good portion of the modern knowledge regarding this topic.
The third objective is to provide the reader with a collection of the most popular and effective ways to manipulate an AQC at the software (middelware) level in order to enhance its performances
Diving into artworks interpretations through the lenses of semantic data: an application on Panofsky's iconological studies
Get PDFIconology and Iconography are branches of art history that focus on recognizing and interpreting the subject matter represented in visual artworks and the deeper meanings possibly conveyed. Due to its complex and interpretative nature, iconographical and iconological knowledge is usually recorded in catalog entries in free text fields, making information retrieval challenging. However, having such curated data described with the accuracy and flexibility offered by ontologies would allow us not only to explore the art history scholarly discourse through quantitative analysis but also to enable a new way to access cultural heritage objects described in the network of Linked Open Data (LOD) through the narratives of experts' interpretations. The current doctoral thesis aimed to fill this gap by presenting 1) an ontology for describing iconographical and iconological interpretations, 2) an RDF dataset including a selection of iconographical and iconological interpretations by the art historian Erwin Panofsky, chosen as a case study, and 3) a quantitative analysis to verify whether data-driven iconological inquiries can be valuable for the domain. The resulting Iconology dataset, described through the newly created ICON ontology, covers core aspects of the domain according to three levels of interpretation and provides every subject recognition with provenance information. Although limited to the interests of the art historian, results show that the availability of such curated, authoritative data, described with a high level of granularity, allows us to quantitatively address traditional art historical questions on several topics and conduct new historiographical inquiries on the art historian's method. Furthermore, the implementation of exploratory data analysis on an online interactive dashboard shows the potential of domain-specific information retrieval.
This contribution opens up the possibility to link artworks at their content level, allowing content-based research questions in art history to cross into the linked open data realm
Caratterizzazione di pompe di calore per stategie di decarbonizzazione con focus relativo all'accoppiamento impianto HVAC - edificio
Get PDFIn this doctoral thesis, the main research activities conducted during the three-year doctoral program are reported, focusing on dynamic simulations and analyses of building-system interactions. Initial investigations evaluated the performance of air-to-water heat pumps across varying climatic conditions, followed by dynamic analyses considering defrost effects. Experimental studies conducted at the University of Bologna's Technical Physics Laboratory aimed to assess a dual-source heat pump's performance, utilizing both ground and external air as thermal sources. The testing apparatus in the laboratory was also characterized.
Further analyses related to geothermal heat pumps coupled with vertical boreholes, incorporating ground-refill via thermal solar collectors during summer are reported. These long-term dynamic simulations show soil temperature drift with and without refill, along with the summer refill's impact on annual machine performance.
In response to the energy crisis and rising prices post-Russo-Ukrainian war, the thesis analyzes the economic feasibility of heat pumps versus gas boilers for winter heating in Italy. Various scenarios were selected, assessing energy and economic savings by adjusting set-point temperatures for spaces heated by either system.
A comfort analyses to assess the impact on comfort of different heating generation systems in a residential building in Bologna is also reported.
Environmental concerns were addressed, with a focus on decarbonization through heat pumps. An analysis determined CO2 emissions from an electric heat pump connected to the Italian grid, establishing hourly emission factors and estimating annual CO2 production.
Lastly, a dynamic analysis of an existing building in Bialystok, Poland, assessed its performance pre- and post-energy retrofit. Virtual relocation to Bologna allowed for performance comparison respect to the Bialystok case. Throughout the thesis, a comprehensive exploration of heat pump technologies, environmental impacts, economic considerations, and building performance dynamics underscores the importance of sustainable heating solutions in mitigating climate change and ensuring energy efficiency.In questa tesi di dottorato, vengono riportate le principali attività di ricerca condotte durante il programma di dottorato, concentrandosi su simulazioni dinamiche relative ad impianti a pompa di calore e su analisi delle interazioni edificio-sistema. Le analisi iniziali hanno valutato le prestazioni delle pompe di calore aria-acqua in varie condizioni climatiche, seguite da analisi dinamiche considerando gli effetti dello sbrinamento. Studi sperimentali condotti presso il Laboratorio di Fisica Tecnica dell'Università di Bologna hanno avuto l'obiettivo di valutare le prestazioni di una pompa di calore a doppia sorgente, utilizzando sia il terreno sia l'aria esterna come fonti termiche.
Sono state analizzate con software di simulazione dinamica anche soluzioni impiantistiche con pompe di calore geotermiche accoppiate a sonde verticali, che prevedono il refill dal terreno tramite collettori solari termici durante l'estate.
In risposta alla crisi energetica e all'aumento dei prezzi post-guerra russo-ucraina, la tesi analizza la fattibilità economica delle pompe di calore rispetto alle caldaie a gas per il riscaldamento invernale in Italia. Sono stati selezionati vari scenari, valutando risparmi energetici ed economici ottenibili utilizzando alternativamente le caldaie a gas o le pompe di calore.
È stato analizzato anche l’impatto del sistema di riscaldamento (caldaia a gas o pompa di calore) sul comfort all’interno di un edificio residenziale a Bologna.
Le tematiche ambientali sono state affrontate, con un focus sulla decarbonizzazione attraverso le pompe di calore. Un'analisi ha determinato le emissioni di CO2 da una pompa di calore elettrica collegata alla rete italiana, stabilendo fattori di emissione orari e stimando la produzione annuale di CO2.
Infine, un'analisi dinamica di un edificio esistente a Białystok, Polonia, ha valutato le sue prestazioni prima e dopo il retrofit energetico.
La tesi riporta considerazioni energetiche, economiche e ambientali che sottolineano l'importanza di soluzioni di riscaldamento sostenibili per mitigare il cambiamento climatico e garantire l'efficienza energetica
Ethnic prejudice: a cross-fertilization approach for understanding its development and correlates from adolescence to emerging adulthood
Get PDFUnderstanding how attitudes toward diversity develop during adolescence is crucial to promote the cohesion of current multicultural societies and support youth’s adjustment to their increasing ethnic and cultural complexity. Such development does not occur in a social void but is rather influenced by the experiences and interactions that adolescents have across multiple environments. Relatedly, this dissertation aimed to examine the development of ethnic prejudice as embedded in and resulting from multiple proximal and distal influences. Chapter 1 provides an overview of the theoretical underpinnings of the dissertation, informed by the ecological systems and transactional models of development and a multidimensional account of affective and cognitive prejudice. The following chapters (Chapter 2 to 10) present a series of empirical studies divided in four sections.
Section A focused on the role of individual (i.e., empathic competences; Chapter 2), personal identity processes (Chapter 3), and social identification (Chapter 4) correlates of ethnic prejudice in adolescence and emerging adulthood. Taking a step further, Section B examined how ethnic prejudice changes within the multiple proximal contexts of development, from the family and classroom (Chapter 5) to study abroad experiences (Chapter 6). Section C tackled the role of distal factors for changes in prejudice. Specifically, it examined how news reports about ethnic minorities (Chapter 7) and the salience of the Russia-Ukraine war (Chapter 8) can influence adolescents’ ethnic prejudice. Section D circled back to the individual level with the aim of understanding the consequences of prejudice for the well-being of ethnic minority (Chapter 9) and majority (Chapter 10) youth.
Last, the concluding chapter (Chapter 11) summarized and discussed the main findings of the current dissertation. Overall, the current dissertation underscores the importance of adopting a multidimensional and ecological account of ethnic prejudice when building interventions aimed at supporting the adjustment of youth in current multicultural societies.Comprendere in che modo gli adolescenti sviluppano i loro atteggiamenti nei confronti della diversità è fondamentale per promuovere il benessere e l’integrazione dei giovani nelle società multiculturali attuali. Lo sviluppo degli atteggiamenti è influenzato dalle esperienze e dalle interazioni che gli adolescenti hanno nei numerosi contesti di vita. Pertanto, questo lavoro di tesi si è posto l’obiettivo di studiare in che modo molteplici influenze prossimali e distali contribuiscono allo sviluppo del pregiudizio affettivo e cognitivo. Il Capitolo 1 offre un inquadramento teorico generale della ricerca, orientata dal modello dei sistemi ecologici e dalla teoria transazionale allo sviluppo. I capitoli successivi (dal Capitolo 2 al Capitolo 10) presentano una serie di studi empirici organizzati in quattro sezioni.
La sezione A ha indagato in che modo fattori individuali (competenze empatiche; Capitolo 2), processi identitari (Capitolo 3) e identificazioni sociali (Capitolo 4) contribuiscono a cambiamenti nei livelli di pregiudizio nei giovani. La Sezione B ha posto l’attenzione su come i contesti prossimali di sviluppo, dalla famiglia alla classe (Capitolo 5) fino alle esperienze di studio all’estero (Capitolo 6), possano influenzare il pregiudizio. La Sezione C ha poi esaminato il ruolo dei fattori distali. Nello specifico, ha indagato in che modo le notizie di giornale riguardanti persone appartenenti alle minoranze etniche (Capitolo 7) e l’attenzione mediatica rivolta alla guerra Russo-Ucraina (Capitolo 8) possono influenzare il pregiudizio. La Sezione D ritorna ad un focus sull’individuo per comprendere le conseguenze del pregiudizio per il benessere di giovani appartenenti al gruppo etnico minoritario (Capitolo 9) e a quello maggioritario (Capitolo 10).
Infine, il capitolo conclusivo (Capitolo 11) discute i risultati principali di questa ricerca. In generale, questo lavoro di tesi sottolinea l’importanza di adottare una prospettiva multidimensionale ed ecologica per studiare il pregiudizio etnico e progettare interventi volti a favorire l’adattamento dei giovani alle società multiculturali attuali
Measurement techniques and models for integrated thermal management and control in electric vehicle design
Get PDFThe persistent rise in global pollution, primarily due to conventional gasoline vehicles, necessitates a shift to sustainable transportation options. Electric vehicles (EVs) offer a clean solution but face challenges, including limited driving range. A crucial aspect affecting EV performance is their thermal management system (TMS), vital for passenger comfort and subsystem operation.
This study focuses on the Electric Thermal Management (e.TM) system in EVs, aiming to enhance efficiency by integrating various thermal regulation systems. It explores the impact of cabin air recirculation on HVAC energy consumption and CO2 levels, utilizing real-time measurements from a crane cabin. The e.TM system adapts thermal regulation to meet cabin, battery, and electronic control unit needs, improving vehicle performance in diverse environments.
Simulations using the Simscape platform evaluate two secondary loop layouts, emphasizing optimal waste heat recovery, particularly in colder conditions. An Intelligent Valve system and a variable PI controller for the heat pumps's compressor ensure precise temperature control across vehicle subsystems.
A Hardware-in-the-Loop (HIL) system combines real heat pump testing with simulation models to evaluate TMS control logic. Despite hardware limitations, the HIL system shows promise for accurate testing, aiding the development of EV thermal management systems
How do entrepreneurial pre-incubation programs work?
Get PDFOver the past decade, pre-incubation programs have received increasing attention from scholars in entrepreneurship. Despite the great attention and interest from scholars, policy makers, and aspiring entrepreneurs, however, there remains a need to understand how entrepreneurial pre-incubation programs work. This thesis aims to shed light on the role of pre-incubation programs in guiding aspiring entrepreneurs in transforming their business ideas into new ventures. To achieve this, it provides a comprehensive overview of current knowledge on entrepreneurship teaching and learning in pre-incubation programs. Then, it analyses whether career preferences of early-career academics drive their entrepreneurial learning in pre-incubation programs. Finally, it estimates the effect of entrepreneurship education treatment on subsequent business creation. The thesis contributes to several strands of literature. First, it contributes to the literature on entrepreneurial education and entrepreneurial ecosystem. Second, it enriches the literature on entrepreneurial learning in pre-incubation programs. Third, it contributes more broadly to the literature on the whether and how pre-incubation programs work. Finally, it provides implications for policy makers, managers, and entrepreneurs. To do so, the research uses primary and secondary data collected from Start Cup Emilia-Romagna, a pre-incubation programs in Italy. The data were analyzed using qualitative and quantitative methods
Development of mass spectrometry methods for the monitoring of chemical contaminants in honey
Get PDFIl miele è al centro di una catena di valore agroalimentare di rilievo in Europa. Tuttavia, la sua purezza può essere compromessa da contaminanti di origine antropica e naturale, rappresentando potenziali rischi per la salute umana. Questa tesi affronta la necessità di sviluppare metodiche innovative e efficienti per il monitoraggio di contaminanti chimici nel miele tramite l’utilizzo della spettrometria di massa, con particolare attenzione a micotossine e pesticidi. La ricerca si è articolata in due fasi principali; la prima fase ha previsto lo sviluppo e la validazione di una metodologia multi-residuale per la determinazione di 19 micotossine e 6 pesticidi nel miele, utilizzando la spettrometria di massa ad alta risoluzione. La seconda fase della ricerca ha avuto come focus l’ottimizzazione e validazione dell’analisi di glifosato, glufosinato e loro metaboliti attraverso LC-MS/MS e IC-HRMS. Con i risultati ottenuti si è potuta dimostrare la comparabilità e l'efficacia degli approcci utilizzati anche a concentrazioni molto basse, fornendo dati affidabili sulla determinazione di contaminanti nei campioni di miele. I protocolli analitici di entrambe le fasi sono stati applicati a campioni di miele reali di varia provenienza, rivelando la presenza di pesticidi organofosfati in due campioni e la presenza di glifosato in più della metà dei campioni sottoposti ad analisi. Durante questo periodo di ricerca è stato possibile evidenziare come l’importanza della valutazione dei metaboliti e il valore di tecniche analitiche che bilancino studio della matrice, sensibilità, selettività e praticità per una valutazione accurata del rischio di esposizione del consumatore. La ricerca fornisce un contributo significativo alla sicurezza alimentare nel settore apistico, promuovendo l'adozione di protocolli analitici armonizzati per garantire coerenza e comparabilità nei dati. Infine, sottolinea l'importanza della sperimentazione e il monitoraggio per affrontare le sfide in evoluzione legate alla sicurezza alimentare e alla preservazione della qualità del miele e della filiera apistica.Honey is at the center of a major agrifood value chain in Europe. However, its purity can be compromised by contaminants of anthropogenic and natural origin, posing potential risks to human health. This thesis addresses the need to develop innovative and efficient methods for monitoring chemical contaminants in honey using mass spectrometry, with a focus on mycotoxins and pesticides. The research consisted of two main phases; the first phase involved the development and validation of a multi-residual methodology for the determination of 19 mycotoxins and 6 pesticides in honey, using high-resolution mass spectrometry. The second phase of the research focused on the optimization and validation of the analysis of glyphosate, glufosinate and their metabolites by LC-MS/MS and IC-HRMS. With the results obtained, it was possible to demonstrate the comparability and effectiveness of the approaches used even at very low concentrations, providing reliable data on the determination of contaminants in honey samples. The analytical protocols of both phases were applied to real honey samples from various sources, revealing the presence of organophosphate pesticides in two samples and the presence of glyphosate in more than half of the samples submitted for analysis. During this research period it was possible to highlight how the importance of metabolite assessment and the value of analytical techniques that balance matrix study, sensitivity, selectivity and practicality for accurate assessment of consumer exposure risk. The research makes a significant contribution to food safety in the beekeeping sector by promoting the adoption of harmonized analytical protocols to ensure consistency and comparability in data. Finally, emphasizes the importance of sperimentation and monitoring to address evolving challenges related to food safety and preservation of honey quality and the bee supply chain
Toward practical depth estimation based on deep learning
Get PDFDepth estimation from images is a classic computer vision problem that has occupied researchers for decades. Obtaining dense and accurate depth estimation is pivotal to effectively address higher-level tasks in computer vision such as autonomous driving, 3D reconstruction, and robotics.
Therefore, with a focus on diverse depth estimation setups, this thesis addresses significant challenges that impact methodologies for inferring depth from images or obtaining completed depth from hardware sensors. The goal is to develop precise and efficient frameworks tailored for accurate Simultaneous Localization And Mapping (SLAM) in challenging environments
Ketogenic supplementations for AGC1 deficiency: investigating epigenetic and metabolic paths to recover proliferation and differentiation of OPCs and NSCs in vitro models
No full textAGC1 deficiency is an ultra-rare demyelinating disease caused by mutations in the SLC25A12 gene, which encodes for isoform 1 of the mitochondrial aspartate-glutamate carrier (AGC1). The main pathological features are brain atrophy, growth retardation and secondary hypomyelination, along with impaired proliferation of brain cells. As demonstrated in patients, the abnormal myelin production is due to a reduced synthesis of N-acetyl-aspartate (NAA), from which the acetyl groups mainly derive. This, in turn, leads to epigenetic alterations in the brain precursor cells and resulting in transcriptional dysregulation, causing proliferation and differentiation defects, as demonstrated by previous data on our in vitro AGC1 deficiency models of our laboratory (precursor cells of mouse oligodendrocytes -OPCs- where SLC25A12 is silenced by a shRNA and neurospheres by mouse model of AGC1 deficiency).
Along with epigenetic alterations, lower production of NAA leads specifically to reduced levels of acetyl-CoA, involved in many biological activities, including the synthesis of fatty acids, major components of the myelin sheath. Thus, an alteration of their production causes hypomyelination. This is confirmed by RNA-seq analysis and in vitro validation on OPCs and on neural stem cells model, which show altered expression of transcriptional factors and enzymes involved in the fatty acid synthesis pathway. Meanwhile, metabolomics analysis shows altered concentrations of many metabolites, as TCA cycle intermediates, amino acids and cofactors (NAD+, CoA); whereas ATAC-seq confirmed the presence of abnormal epigenetic landscape, which could affect genes involved in many biological pathways.
To try to rebalance the epigenetic and metabolic alterations, supplementations with ketogenic compounds, as branched-chain amino acids and ketone bodies, will be carried out on OPCs and neurospheres, to induce a potential recovery of differentiation/proliferation defects, through epigenetic modifications restoration