10081 research outputs found
Sort by
Experimental study on innovative sustainable recycled fibres for high performance asphalt concretes
No full textThe growing consumption of heated tobacco products (HTPs) has led to a significant accumulation of electronic cigarette butts (E-CBs), which degrade slowly and contain toxic chemicals, contributing to environmental pollution. To address this issue, this thesis explores the potential of recycling E-CBs as fibre additives in asphalt mixtures, providing a sustainable alternative to traditional cellulose fibres.
The study specifically investigates the use of E-CBs in Stone Mastic Asphalt (SMA), mixtures containing Reclaimed Asphalt Pavement (RAP), and Warm Mix Asphalt (WMA). E-CBs were processed through shredding and pelletizing, and their effects on drain-down, volumetric, and mechanical properties were assessed. The results show that shredded E-CBs effectively absorb bitumen, resulting in acceptable air void content and mechanical properties in SMA. However, E-CB powders were found to negatively affect the thermal stability and rutting resistance of the mastic. Larger shredded E-CBs (15 mm) demonstrated better performance in terms of tensile strength, stiffness, and rutting resistance compared to smaller ones (10 mm). While the plastic content of E-CBs increased thermal susceptibility, it enhanced resistance to permanent deformation. Further innovation was achieved through the development of engineered fibre pellets made from shredded E-CBs using 3D printed molds. The SMA using Pellet Ⅰ (composed solely of E-CBs) can satisfy the technical specifications regarding the tests performed in this study. Pellet Ⅱ, which incorporated both E-CBs and a recycling agent, improved fatigue performance in SMA mixtures with 40% RAP without compromising other mechanical properties. The use of pelletized fibres containing Fischer-Tropsch wax enabled WMA production at lower temperatures, but their impact on workability and mechanical properties was limited compared to the conventional method of adding the wax. The conclusions drawn from this thesis highlight the potential of recycling E-CBs as a sustainable fibre additive in asphalt mixtures, presenting an eco-friendly alternative to conventional materials
Statistical modelling of heterogeneity in the human gut microbiome
No full textResearch on the gut microbiome is becoming essential for understanding human health and the role of the microbiota on biological systems and disorders, emphasizing the importance of clustering individuals according to their microbiome configuration. This thesis explores different strategies to obtain these groups. In the first part we focus on clustering methods that exploit the individual profile information, proposing two models generally applicable to count data. The former is a Poisson generalized linear latent variable mixture model which identifies clusters of samples sharing the same features and simultaneously allows for the correlation between variables. The second proposal aims to extend multivariate Poisson-Lognormal (MPLN) mixtures to the high-dimensional setting. To do that, we start focusing on the general Gaussian mixture model framework, proposing a Random Projection Ensemble covariance estimate. Then, the application of the proposal to the latent layer of MPLN mixtures is investigated. In the second part the focus moves to diversity-based methods. Here we develop a Bray-Curtis dissimilarity-based mixture model, with the possibility of adding the α-diversity as covariate. Concurrently, we propose a two-step algorithm which clusters samples according to their within-individual diversity, and then it further divides them based on the inter-individual variability. Afterwards, individual profiles and diversity measures are combined in a cosine distance-based mixture model with covariates. In the third part, literature methods and the new approaches are applied to simulated and real microbiome data. The latter show how results depend on the method and distance used. Considering metadata, body mass index, gender and age often turned out to be among the most important variables in explaining the gut microbiome composition, while the type of diet among the least important, maybe for an overly simplistic categorization. However, the metadata analysed appear to explain a very small portion of the differences in the microbiome configurations found
Electrodeposited catalysts for selective electrocatalytic reduction of HMF and CO2: insights into mechanisms and selectivity control
No full textThis thesis investigates advanced electrocatalytic processes for sustainable chemical production, focusing on converting biomass-derived compounds and CO2 into valuable chemicals and fuels. Grounded in green chemistry principles, it emphasizes renewable feedstocks and electrocatalysis as foundations for a new chemical industry.
The initial research examines the electrocatalytic reduction of 5-hydroxymethylfurfural (HMF), a key biomass-derived platform molecule, using Ag/Cu bimetallic catalysts. The conversion of HMF to 2,5-bis(hydroxymethyl)furan (BHMF) is explored in both pure HMF solutions and HMF-rich hydrolyzates from inulin, aiming to avoid costly and energy-intensive separations. The Ag/Cu foam catalyst exhibited high BHMF selectivity, even with real feedstocks, showing industrial scalability potential.
Mechanistic studies of HMF reduction reveal competition between desired products like BHMF and side products such as bis(hydroxymethyl)hydrofuroin (BHH). Experimental and computational analyses underscore the role of catalyst composition and applied potential in determining product selectivity.
Further work evaluates Pd/Au-based catalysts for HMF electrocatalysis, focusing on how hydride formation influences activity. Modulating hydrogen atom transfer and hydride formation was shown to enhance selectivity for targeted products.
The final section addresses the electrocatalytic reduction of CO2 to C2 molecules like ethylene and ethanol using Cu-based catalysts in flow cell reactors. Optimized electrodeposition conditions significantly improved C2 product selectivity, advancing scalable CO2 reduction technologies.
This thesis contributes to sustainable electrocatalysis, offering insights into catalyst design, mechanistic pathways, and process optimization for industrial applications in biomass valorization and carbon dioxide reduction
Communication and empire: interpreters, networks and archive in early portuguese exploration (ca.1500-1520)
No full textThrough different case studies from different observation points across the Portuguese empire and its archive, this dissertation’s focus is the emergence of an early global communication apparatus, that of the Portuguese empire in the sixteenth century, via the lens of some of its most decisive contributors: interpreters. Communication in the Portuguese empire of course included acts of linguistic mediation, in a context of rapidly increasing linguistic friction across this global space and its fringes, be it in Benin, Kongo or Malabar. In this empire in the making, the role multilingual agents played in retrieving information from beyond lusophone circles was as discreet as it was central. Yet by following the circulation of information beyond these fringes and into the imperial communication channels, this dissertation focuses on the processes through which this information made it onto paper, and through correspondence how it arrived in Lisbon, where the documents on which it was contained gradually came to compose the imperial archive. In doing so, this dissertation is hence also focused on the emergence of an archive, that produced by the first generation of multilingual actors who, through their intervention, did not only contribute to fashioning the empire on its fringes, but also left their mark on the archival trails which eventually converged to Lisbon
Theories and practices for prison libraries: a pedagogical perspective.
No full textLa ricerca si propone di comprendere qual è e quale potrebbe essere il ruolo delle biblioteche nei percorsi di inclusione delle persone che si trovano a scontare parte della loro vita in carcere. Dopo aver analizzato le prospettive attraverso cui indagare gli ambienti penitenziari, aver esaminato normative e documenti nazionali ed internazionali e aver compreso quali fossero le prospettive pedagogiche più adatte per pensare l’agire educativo in carcere, la ricerca si è occupata di raccogliere ed analizzare i dati narrativi emersi da sei racconti di vita. Assumendo che la biblioteca sia un possibile luogo di cura educativa, si sono indagate le narrazioni, le rappresentazioni ed i vissuti di ex detenute ed ex detenuti rispetto all’accesso e alla fruizione delle biblioteche in carcere. Luoghi liminali di scambio tra il dentro e il fuori, le biblioteche sono state pensate sia nella loro funzione di luoghi deputati alla lettura individuale, destinata allo studio o alla cura di sé, sia come spazio che offre occasioni di relazione e di incontro. Le osservazioni sugli spazi della biblioteca e sui significati che le persone vi attribuiscono sono messe al centro di una più ampia riflessione sul lavoro educativo negli Istituti di pena, volto a supportare le persone detenute in processi trasformativi di liberazione.The research aims to understand the current and potential role of libraries in the inclusion pathways of individuals who spend part of their lives in prison. After analyzing the perspectives for investigating penitentiary environments, examining national and international regulations and documents, and understanding the most suitable pedagogical approaches for educational actions in prisons, the research focused on collecting and analyzing narrative data from six life stories. Assuming that the library is a potential place for educational care, the narratives, representations, and experiences of former inmates regarding access to and use of prison libraries were investigated. Seen as liminal spaces facilitating exchange between the inside and the outside, libraries were regarded both as places for individual reading, dedicated to study or self-care, and as spaces providing opportunities for relationships and encounters. Observations on the library spaces and the meanings attributed to them by individuals are central to a broader reflection on educational work in penal institutions, aimed at supporting inmates in transformative processes of liberation
Models and methods for damage and quantitative risk assessment of Natech scenarios
No full textNatural events are a widely recognized hazard for industrial sites where relevant quantities of hazardous substances are handled, due to the possible generation of cascading events resulting in severe technological accidents (Natech scenarios). Natural events may damage storage and process equipment containing hazardous substances, that may be released leading to major accident scenarios called Natech events. The need to assess the risk associated with Natech scenarios is growing and methodologies were developed to allow the quantification of Natech risk, considering both point sources and linear sources as pipelines. A key element of these procedures is the use of vulnerability models providing an estimation of the damage probability of equipment or pipeline segment as a result of the impact of the natural event. Therefore, the first aim of the PhD project was to outline the state of the art of vulnerability models for equipment and pipelines subject to natural events such as floods, earthquakes, and wind. Moreover, the present PhD project also aimed at the development of new vulnerability models in order to fill some gaps in literature. In particular, a vulnerability model for vertical equipment subject to wind and to flood were developed. Finally, in order to improve the calculation of Natech risk for linear sources an original methodology was developed for Natech quantitative risk assessment methodology for pipelines subject to earthquakes. Overall, the results obtained are a step forward in the quantitative risk assessment of Natech accidents. The tools developed open the way to the inclusion of new equipment in the analysis of Natech events, and the methodology for the assessment of linear risk sources as pipelines provides an important tool for a more accurate and comprehensive assessment of Natech risk
Plea bargaining and penal orders: an empirical approach to disappearing criminal trials
No full textThe present dissertation investigates the global adoption and use of administratization mechanisms, which enable the imposition of criminal convictions without trial. Two administratization mechanisms are currently adopted worldwide: plea bargaining and penal orders. This dissertation shows that administratization procedures are regulated in 125 jurisdictions worldwide, with plea bargaining being allowed in 101 jurisdictions and penal orders in 51. Historical patterns are explored, discussing the adoption of plea bargaining and penal orders in connection with the comparative success of inquisitorial and adversarial models in criminal procedure and with the more recent and global strive for efficiency in criminal law enforcement. The use in practice of administratization mechanisms is also explored, showing their prevalence over ordinary trials in Europe, the Americas, and Eastern Asia. Reasons driving the adoption of plea bargaining are analyzed in cross-country regressions, revealing the significant influence of legal origins, Sharia, democratic governance, and material resources. Legal origins and material resources, together with the existence of jury trials, also correlate with differing levels of use of plea bargaining across jurisdictions. Specific factors influencing the use of administratization mechanisms are then explored with reference to Italy through instrumental variable analyses. The results show that longer trial delays reduce the use of both plea bargaining and penal orders in Italy. The favored explanation is that the Italian criminal statute of limitations, by mandating the acquittal of defendants in case of longer trial delays, provides defendants with strong incentives against the use of administratization mechanisms. The use of both plea bargaining and penal orders is also reduced in Italy by higher concentrations of lawyers in judicial districts. In fact, when facing higher market competition, lawyers might advise their clients against the use of administratization mechanisms, since ordinary trials yield higher financial returns for them
Criminal liability in complex organisations. Dogmatic and criminal political profiles
No full textDinanzi alle fluide dinamiche riconducibili all’azione delle organizzazioni complesse molte delle tradizionali categorie della dogmatica penalistica paiono cadere in una profonda crisi da complessità, richiedendo all’interprete impegnative torsioni ermeneutico-concettuali, non sempre in linea con il volto costituzionale dell’illecito penale. Il risultato di tali sforzi interpretativi restituisce l’immagine di un sistema penale in sofferenza, irragionevolmente focalizzato sulla punizione del singolo, spesso selezionato in base a criteri che ignorano la complessità della formazione delle decisioni nell’organizzazione. Con sempre più urgenza, allora, si impone la necessità di affinare valide strategie politico-criminali che si rivolgano direttamente all’organizzazione, avendo cura di differenziare le modalità d’intervento a seconda della tipologia di struttura meta-individuale di riferimento. Se rispetto all’organizzazione operante in un contesto di base lecito l’obiettivo principale pare quello di restaurare un comune orizzonte di fiducia, un approccio differente deve orientare l’intervento dello ius puniendi rispetto alla societas sceleris e all’ente sospetto, mirando rispettivamente alla dissolution dell’organizzazione criminale e alla risocializzazione d’ente deviante, ma ancora recuperabile ad un paradigma di legalità.Faced with the fluid dynamics ascribable to the action of complex organisations, many of the traditional categories of criminal dogmatics seem to fall into a profound complexity crisis, requiring the interpreter to make demanding hermeneutic-conceptual torsions, not always in line with the constitutional face of the criminal offence. The result of such interpretative efforts returns the image of a penal system in distress, unreasonably focused on the punishment of the individual, often selected on the basis of criteria that ignore the complexity of decision-making in the organisation. With ever-increasing urgency, then, there is a need to refine valid criminal-political strategies that address the organisation directly, taking care to differentiate the modes of intervention according to the type of meta-individual structure of reference. If, with respect to the organisation operating in a lawful basic context, the main objective seems to be that of restoring a common horizon of trust, a different approach must orientate the intervention of the ius puniendi with respect to the societas sceleris and the suspect entity, aiming respectively at the dissolution of the criminal organisation and the re-socialisation of the deviant entity, but still recoverable to a paradigm of legality
Development of functional materials and electrospun devices for the prevention of the spreading of infectious diseases
No full textThis Thesis addresses critical challenges posed by the COVID-19 pandemic, focusing on the transmission dynamics, shortage of face masks, and the urgent need for reliable diagnostics. Initially, the lack of comprehensive information on transmission modes, particularly aerosolized and fomite transmission, and the significance of asymptomatic carriers fueled debates. The surge in demand for face masks strained global production, especially in China, the epicenter of the pandemic. Common disinfection methods for face masks proved unsuitable, prompting research into alternative materials.
The study involves an extensive analysis of surgical mask durability, revealing a decline in filtration efficiency with extended use. A protocol was developed to estimate real-world mask lifespan through empirical evaluations. Simultaneously, alternative face mask filters were developed using electrospun polyvinylidene fluoride (PVDF) material, demonstrating superior bacterial filtration efficiency, breathability, and long-lasting electrostatic properties.
To explore the potential of face masks in viral material collection, preliminary tests using commercial masks and electrospun filters were conducted with Bovine Coronavirus as a model virus. Electrospun PVDF masks exhibited higher virus recovery efficiency than commercial masks, suggesting their utility as sample collection devices.
Furthermore, the Thesis introduces a novel autodiagnostic material for surface disinfection, crucial for fomite transmission prevention. The material, composed of a solvatochromic PA6,6 electrospun layer, a superabsorbent layer for disinfectant release, and a protective plastic film, changes color upon disinfectant depletion. Proof-of-concept experiments validated its regenerable disinfection capabilities for at least 24 hours.
In conclusion, this Thesis contributes to understanding face mask dynamics during a pandemic, proposes an electrospun PVDF alternative, explores face masks for viral sample collection, and introduces a novel autodiagnostic material for efficient and regenerable surface disinfection. These findings have significant implications for public health, providing insights and solutions to combat infectious diseases
Energy storage solutions toward future trolleybus networks for increasing public transport electrification
No full textIn the future, the infrastructure of trolleybus networks will tend to suffer a significant increase in power demand due to the trend of increasing the electrification of public transport. The increase of conventional trolleybuses and the emergence of new vehicle fleets moved by on-board batteries, including ones capable of In-Motion-Charging (IMC) technology are responsible for this increase in power demand.
This PhD dissertation presents solutions to modernize trolleygrids in view of this future condition, without the need to perform major modifications in the infrastructure such as, but not limited to, the construction of new traction substations (TSs) or the replacement of current overhead contact lines (OCLs) by ones with larger gauges.
Modeling trolleybus systems is a crucial step for designing purposes of trolleygrid infrastructures, especially when considering the operation of new fleet technologies (e.g., IMC). In this context, the first topic discussed in this work involves presenting the procedure for simulating trolleybus systems within the scope of this dissertation.
The second discussed topic is the grid congestion in AC distribution networks that the rising electrification of urban transportation systems can cause. The proposed solution involves adopting Energy Storage Systems (ESSs) to reduce power demand at TSs. Different types of Lithium-Ion batteries are compared, focusing on the types of Lithium Titanate Oxide and Lithium Iron Phosphate, as well as their second-life versions.
The third discussed topic proposes solutions to mitigate high voltage drops at vulnerable OCL points, which could jeopardize trolleybus vehicle operation and increase Joule loss in the system.
As the deployment of second-life batteries in stationary applications tends to be prevalent, their integration into the OCL infrastructure is explored. Investigations were performed to determine the conditions under which the operation of an ESS in the middle of a section does not affect the overall efficiency of the trolleybus system