Studio di Shelf-life di taralli formulati con miscele lipidiche diverse

La conservabilità dello snack tipico della panetteria italiana "Tarallini" dipende dalla ricetta e dalle condizioni di cottura e conservazione. In questo lavoro di tesi si è studiata la stabilità ossidativa di taralli formulati con miscele lipidiche diverse durante un periodo di shelf life di circa due mesi e mezzo. I campioni sono stati formulati con olio EVO, con una miscela di olio EVO e olio di riso e il terzo campione è costituito da olio di girasole alto oleico e olio di cocco. Per poter valutare come la diversa frazione lipidica e come anche le interazioni con gli ingredienti propri del campione possano influenzare la conservabilità di taralli, sono state svolte analisi sull'ossidazione lipidica degli olii. In particolare è stata svolta la determinazione dei prodotti primari dell'ossidazione, determinazione dei perossidi; poi sono stati quantificati i prodotti secondari, ovvero i composti volatili, in particolare Esanale che è il composto target per valutare l'ossidazione dell'alimento; ed infine i campioni sono stati sottoposti ad OXITEST, un test di ossidazione accelerata. Dallo studio effettuato emerge che il campione formulato con EVO nonostante sia più suscettibile all'ossidazione è quello che presenta caratteristiche organolettiche e nutritive migliori, a differenza degli altri due campioni che resistono meglio all'ossidazione lipidica, in particolare il campione formulato con olio di girasole altro oleico e olio di cocco.

High friction and acoustic surface for pavements: development of artificial engineered aggregates from recycled powders

There is a constant need to improve the infrastructure's quality and build new infrastructure with better designs. The risk of accidents and noise can be reduced by improving the surface properties of the pavement. The amount of raw material used in road construction is worrisome, as it is finite and due the waste produced. Environmentally-friendly roads construction, recycling might be the main way. Projects must be more environmentally-friendly, safer, and quieter. Is it possible to develop a safer, quieter and environmentally-friendly pavement surfaces? The hypothesis is: is it possible to create an Artificial Engineered Aggregate (AEA) using waste materials and providing it with a specific shape that can help to reduce the noise and increase the friction? The thesis presents the development of an AEA and its application as a partial replacement in microsurfacing samples. The 1st introduces the topic and provides the aim and objectives of the thesis. The 2nd chapter – presents a pavement solution to noise and friction review. The 3rd chapter - developing a mix design for a geopolymer mortar that used basalt powder. The 4th chapter is presented the physical-mechanical evaluation of the AEA. The 5th chapter evaluates the use of this aggregate in microsurfacing regarding the texture parameters. The 6th chapter, those parameter are used as an input to SPERoN® model, simulating their noise behavior of these solutions. The findings from this thesis are presented as partial conclusions in each chapter, to be closed in a final chapter. The main findings are: the DoE provided the tool to select the appropriate geopolymer mortar mix design; AEA had interesting results regarding the physical-mechanical tests; AEA in partial replacement of the natural aggregates in microsurfacing mixture proved feasible. The texture parameters and noise levels obtained in AEA samples demonstrate that it can serve as a HIFASP

Vulnerable users' protection with advanced recycling paving materials. Design and characterisation of rubber-based impact-absorbing pavement materials for bike lanes and sidewalks

Our cities are constantly evolving, and the necessity to improve the condition and safety of the urban infrastructures is fundamental. However, on the roads, the specific needs of cyclists and pedestrians are often neglected. The Vulnerable Road Users (VRUs), among whom cyclists and pedestrians are, rarely benefit from the most innovative safety measures. Inspired by playgrounds and aiming to reduce VRUs injuries, the Impact-Absorbing Pavements (IAP) developed as novel sidewalks, and bike lanes surface layers may help decrease injuries, fatalities, and the related societal costs. To achieve this goal, the End-of-Life Tyres (ELTs) crumb rubber (CR) is used as a primary resource, bringing its elastic properties into the surface layer. The thesis is divided into five main chapters. The first concerns the formulation and the definition of a feasible mix. The second explores the mechanical and environmental properties in detail, and the ageing effect is also assessed. The third describes the modelling of the material to simulate accidents and measure the injury reduction, especially on the head. The fourth chapter is reserved for the field trial. The last gives some perspectives on the research and proposes a way to optimize and improve the data and results collected during the doctoral research. It was observed that the specimens made with cold protocol have noticeable performances and reduce the overall carbon footprint impact of this material. The material modelling and the accident simulation proved the performance of the IAP against head injuries, and the field trial confirmed the good results obtained in the laboratory for the cold-made material. Finally, the outcomes of this thesis opened many prospective to the IAP development, such as the use of a plant-based binder or recycled aggregates and gave a positive prospect of an innovative material to the urban road infrastructures.

Solutions for the conservation and restoration of cement-based materials in XX Century architectural heritage

Among the most representative materials of XX Century architectural heritage, this dissertation focuses on the cement-based ones, investigating some different fields where they were exploited. Primarily, concerning the surface preservation of cement-based materials used with aesthetic intent, new self-cleaning treatments based on titania nanoparticles embedded in inorganic matrices were tested. In order to consider the role of porosity, the treatments were applied to different kinds of materials (cement-based mortar, marble and concrete) and several analyses were conducted to investigate the morphology of the coatings, their photocatalytic effectiveness, their durability and the interaction between the coating and the substrate material. The outcomes showed that several parameters influence the treatment’s performances, in particular, the presence and nature of the matrix, the concentration and dispersion of nanoparticles and, in some cases, the amount of substrate material which interacts with the coatings. Secondly, this dissertation deals with the historic “Terranova” render, a colored dry-mix mortar largely widespread in Europe in the first half of XX Century, whose formulation is still basically unknown. Some original samples of supposedly Terranova renders were subjected to several characterization analyses and the results were compared to those of the original “Terranova” render of the Engineering Faculty in Bologna. Despite the recurrence of some features, defining a common formulation seemed to be challenging. Finally, the repair and conservation of structural reinforced concrete in heritage buildings were investigated, adopting the former “Casa del Fascio” in Predappio (FC, Italy) as case study. Three different materials and solutions were tested on a slab of the building, making its repair only from the intrados. Then several analyses were conducted both on site and in laboratory. Aside from the specific features characterizing every product, the results highlighted that the application method played a fundamental role in the effectiveness of the retrofit strategies.

Low carbon systems for climate change mitigation and adaptation

Global warming and climate change have been among the most controversial topics after the industrial revolution. The main contributor to global warming is carbon dioxide (CO2), which increases the temperature by trapping heat in the atmosphere. Atmospheric CO2 concentration before the industrial era was around 280 ppm for a long period, while it has increased dramatically since the industrial revolution up to approximately 420 ppm. According to the Paris agreement it is needed to keep the temperature increase up to 2°C, preferably 1.5° C, to prevent reaching the tipping point of climate change. To keep the temperature increase below the range, it is required to find solutions to reduce CO2 emissions. The solutions can be low-carbon systems and transition from fossil fuels to renewable energy sources (RES). This thesis is allocated to the assessment of low-carbon systems and the reduction of CO2 by using RES instead of fossil fuels. One of the most important aspects to define the location and capacity of low-carbon systems is CO2 mass estimation. As mentioned, high-emission systems can be substituted by low-carbon systems. An example of high-emission systems is dredging. The global CO2 emission from dredging is relatively high which is associated with the growth of marine transport in addition to its high emission. Thus, ejectors system as alternative for dredging is investigated in chapter 2. For the transition from fossil fuels to RES, it is required to provide solutions for the RES storage problem. A solution could be zero-emission fuels such as hydrogen. However, the production of hydrogen requires electricity, and electricity production emits a large amount of CO2. Therefore, the last three chapters are allocated to hydrogen generation via electrolysis, at the current condition and scenarios of RES and variation of cell characteristics and stack materials, and its delivery.

Sustainable pavements for rural scenarios: laboratory and in-situ characterization of recycled materials and innovative construction solutions

Growing need for infrastructure has led to expanding research on advances in road pavement materials. Finding solutions that are sustainable, environmentally friendly and cost-efficient is a priority. Focusing such efforts on low-traffic and rural roads can contribute with a significant progress in the vital circulatory system of transport for rural and agricultural areas. An important alternative material for pavement construction is recycled aggregates from solid wastes, including waste from civil engineering activities, mainly construction and demolition. A literature review on studies is made; it is performed a planned set of laboratory testing procedures aimed to fully characterize and assess the potential in-situ mechanical performance and chemical impact. Furthermore, monitoring the full-scale response of the selected materials in a real field construction site, including the production, laying and compaction operations. Moreover, a novel single-phase solution for the construction of semi-flexible paving layers to be used as alternative material to common concrete and bituminous layers is experimented and introduced, aiming the production and laying of a single-phase laid material instead of a traditional two phases grouted macadam. Finally, on a parallel research work for farming pavements, the possible use of common geotechnical anti-erosive products for the improvement of soil bearing capacity of paddock areas in cattle husbandries of bio-farms is evaluated. this thesis has clearly demonstrated the feasibility of using the sustainable recycled aggregates for low-traffic rural roads and the pavements of farming and agriculture areas. The pavement layers constructed with recycled aggregates provided satisfying performance under heavy traffic conditions in experimental pavements. This, together with the fact that these aggregates can be available in most areas and in large quantities, provides great impetus towards shifting from traditional materials to more sustainable alternatives. The chemical and environmental stability of these materials proves their soundness to be utilized in farming environments.

Excitonic properties of transition metal oxide perovskites and workflow automatization of GW schemes

The Many-Body-Perturbation Theory approach is among the most successful theoretical frameworks for the study of excited state properties. It allows to describe the excitonic interactions, which play a fundamental role in the optical response of insulators and semiconductors. The first part of the thesis focuses on the study of the quasiparticle, optical and excitonic properties of \textit{bulk} Transition Metal Oxide (TMO) perovskites using a G$_0$W$_0$+Bethe Salpeter Equation (BSE) approach. A representative set of 14 compounds has been selected, including 3d, 4d and 5d perovskites. An approximation of the BSE scheme, based on an analytic diagonal expression for the inverse dielectric function, is used to compute the exciton binding energies and is carefully bench-marked against the standard BSE results. In 2019 an important breakthrough has been achieved with the synthesis of ultrathin SrTiO3 films down to the monolayer limit. This allows us to explore how the quasiparticle and optical properties of SrTiO3 evolve from the bulk to the two-dimensional limit. The electronic structure is computed with G0W0 approach: we prove that the inclusion of the off-diagonal self-energy terms is required to avoid non-physical band dispersions. The excitonic properties are investigated beyond the optical limit at finite momenta. Lastly a study of the under pressure optical response of the topological nodal line semimetal ZrSiS is presented, in conjunction with the experimental results from the group of Prof. Dr. Kuntscher of the Augsburg University. The second part of the thesis discusses the implementation of a workflow to automate G$_0$W$_0$ and BSE calculations with the VASP software. The workflow adopts a convergence scheme based on an explicit basis-extrapolation approach [J. Klimeš \textit{et al.}, Phys. Rev.B 90, 075125 (2014)] which allows to reduce the number of intermediate calculations required to reach convergence and to explicit estimate the error associated to the basis-set truncation.

Study of recycled Rap and Ra as alternative aggregates for pavements' sub-base and base

Nowadays, an important world’s population growth forecast establish that an increase of 2 billion people is expected by 2050. (UN,2019). This increment of people worldwide involves more humans, as well as growth of the demand for the construction of new residential, institutional, industrial, and infrastructural areas, prompting to a higher consumption of natural resources as required for construction materials. In addition, an effect of this population growth is the production and accumulation of waste causing a serious environmental and economic issue around the world. As an alternative to just producing more waste at the final stage of a building, house, road, among other concrete-based structures, adequate techniques must be applied for recycling and reusing these potential materials. The main priority of the thesis is to foment and evaluate the sustainable construction work leading to environmental-friendly actions that promote the reuse and recycling of construction waste, focusing on the use of construction recycled construction materials as an alternative for sub-base and base of road structure application. This thesis is committed to the analysis of the several laboratory tests carried out for achieving the physical-mechanical properties of the studied materials (recycled concrete aggregates + reclaimed asphalt pavement (RCA+RAP) and stabilized crushed sleepers). All these tests have been carried out in the Laboratory of Roads from the University of Bologna and in the experimental site in CAR srl., at Imola. The results are reported in tables, graphs, and are discussed. The mechanical properties values obtained from the laboratory tests are analysed and compared with standard values declared in the Italian and European normative for roads construction and to the results obtained from in-situ tests in the experimentation field (CAR srl in Imola) with the same materials. This to analyse the performance of them under natural conditions.

Prodotti dell'alveare: la propoli e le sue proprietà benefiche

La propoli è una sostanza naturale prodotta dalle api operaie in seguito alla raccolta di resine ed estratti vegetali; è impiegata nell’alveare come materiale di costruzione con funzione cementante e protettiva. Essendo un prodotto di origine naturale, la sua composizione è estremamente complessa ed allo stesso tempo peculiare: molteplici sono le sostanze chimiche che ne fanno parte, la loro presenza e concentrazione dipende dal luogo d’origine, dall’ape, dalla stagione, dalla specie vegetale bottinata e da numerose altre variabili. È importante considerare la variabilità compositiva della propoli per poterne valutare le caratteristiche qualitative, che ancora oggi non sono ufficialmente definite a livello Europeo, ma che fanno riferimento principalmente all’intensità con cui essa è in grado di determinare effetti benefici nell’uomo. Dalla peculiarità delle molecole che la compongono emergono le sue potenzialità come sostanza antimicrobica, antiossidante, antiinfiammatoria ed antitumorale, caratteristiche che la rendono sempre più spesso oggetto di studi e ricerche scientifiche. In questo studio vengono messi a confronto i risultati ed i metodi analitici degli studi effettuati su tale matrice: ne deriva una forte difformità, data dall’origine dei campioni e dalla impossibilità, ad oggi, di ottenere un prodotto standardizzato.

Light coloured and draining wearing courses for low-impact urban pavements

Urban health and well-being are becoming current issues of modern cities due to local climate change and environmental noise. The Urban Heat Island and the Urban Noise Island have a direct impact on the economic, social, and environmental aspects of urban life, negatively affecting the well-being of worldwide citizens. The present research is focused on the study of innovative materials employed in the production of wearing course mixtures aiming to mitigate these phenomena. In particular, a synthetic transparent binder substituting bitumen and recycled aggregates produced from construction and demolition waste. Four mixtures were analysed. Among them, Mix 1 and Mix 2 are conventional wearing courses. The first is exclusively made of natural aggregates, while the second is constituted of 45 % of recycled aggregates (RA). Mix 3 and Mix 4 are draining wearing courses and, in this case, Mix 4 was produced by using 55 % of RA. Laboratory tests were required to fully characterize all the produced samples, allowing a proper comparison of results. Overall, all the mixtures studied provide prominent results suggesting potential applications of these innovative wearing courses in cycle lanes, historical centres, plazas, and parking lots. Among the conventional mixtures, Mix 2 is the most likely to assure the best performance in terms of road safety, efficiency, and durability while as far as the draining mixtures are concerned, Mix 4 is preferable due to its high content of recycled aggregates.

Effetto della luce sull'innesco dell'ossidazione di oli vegetali

L’obiettivo di questo studio è quello di valutare la stabilità foto-ossidativa di oli vegetali esposti a luce ultravioletta di bassa intensità per tempi brevi (da 5 min a 8 ore); lo scopo è quello di monitorare le prime fasi di ossidazione. Per la realizzazione di questo studio, è stato messo a punto un sistema di foto-ossidazione al fine di poter adottare condizioni di analisi le più ripetibili possibili e al fine di poter escludere il possibile effetto della temperatura. I campioni di olio analizzati nel presente lavoro di ricerca, tre oli raffinati e un olio extravergine di oliva, sono stati posti in provette di vetro trasparente da 20 ml, caricati poi all’interno della camera di ossidazione in gruppi di quattro e lasciati sotto l’effetto della luce ultravioletta per diversi tempi ovvero 0, 5, 10, 20, 30, 60, 240 e 480 minuti. Sono stati presi in considerazione i seguenti parametri qualitativi di analisi per valutare lo stato ossidativo dei nostri campioni, e cioè il numero di perossido, la concentrazione di esanale e il valore di p-anisidina. Dai risultati ottenuti è stato possibile osservare che complessivamente, a livelli di insaturazione e di presenza di antiossidanti naturali differenti, l’impatto dell’esposizione alla luce è stato piuttosto simile. I tre oli raffinati hanno mostrato valori ossidativi più contenuti, mentre per l’olio EVO sono state rilevate concentrazioni più alte sia per i perossidi che per l’esanale. Questo è dovuto alla presenza di alcuni composti ad azione pro-ossidante e composti aromatici che permangono nel prodotto in quanto questo olio non subisce il processo di raffinazione. La p-anisidina per tutte e quattro gli oli testati è rimasta piuttosto costante e lineare nel tempo senza subire considerevoli variazioni. Questo sottolinea il fatto che le condizioni di stress foto-ossidativo impiegate non sono state sufficienti a determinare un aumento significativo dei prodotti di ossidazione secondaria.

Analisi delle prestazioni di un sistema di accumulo termico

Analisi termofluidodinamica di un accumulatore di calore che utilizza materiali a cambiamento di fase (PCM). I campi di velocità, di temperatura e di titolo, in regime termico non stazionario, relativi al singolo canale, vengono calcolati con un programma basato sul metodo dei volumi finiti, scritto in ambiente di lavoro Matlab. Vengono proposte diverse ottimizzazioni delle performance di accumulo termico, basate su un algoritmo genetico. Le ottimizzazioni sono fatte sia con differenti tipi di parametri di valutazione, sia con differenti gradi del polinomio che descrive la parete del canale; per ogni ottimizzazione l’algoritmo genetico è stato, quindi, utilizzato per determinare i parametri geometrici del canale ottimali. A partire dai risultati ottenuti dalle ottimizzazioni, vengono poi analizzate le prestazioni di canali della stessa geometria, ai quali viene aggiunta un’intelaiatura metallica. Vengono, infine, mostrati i risultati delle simulazioni numeriche fatte.

Analytical and numerical study of polarons

The aim of this thesis is to introduce the polaron concept and to perform a DFT numerical calculation of a small polaron in the rutile phase of TiO2. In the first chapters, we present an analytical study of small and large polarons, based on the Holstein and Fröhlich Hamiltonians. The necessary mathematical formalism and physics fundamentals are briefly reviewed in the first chapter. In the second part of the thesis, Density Functional Theory (DFT) is introduced together with the DFT+U correction and its implementation in the Vienna Ab-Initio Simulation Package (VASP). The calculation of a small polaron in rutile is then described and discussed at a qualitative level. The polaronic solution is compared with the one of a delocalized electron. The calculation showed how the polaron creates a new energy level 0.70 eV below the conduction band. The energy level is visible both in the band structure diagram and in the density of states diagram. The electron is localized on a titanium atom, distorting the surrounding lattice. In particular, the four oxygen atoms closer to the titanium atom are displaced by 0.085 Å outwards, whereas the two further oxygen atoms by 0.023 Å. The results are compatible, at a qualitative level, with the literature. Further developments of this work may try to improve the precision of the results and to quantitatively compare them with the literature.

Nuovi trattamenti protettivi autopulenti a base di biossido di titanio per i materiali cementizi nel restauro dell’architettura del XX secolo: risultati di uno studio sperimentale in laboratorio

La presente tesi di laurea è finalizzata allo sviluppo di nuovi trattamenti protettivi autopulenti a base di biossido di titanio (TiO2) per la conservazione dei materiali cementizi storici tipici dell’architettura del XX secolo. Tale studio nasce dal crescente interesse verso i temi del restauro del Moderno così come testimoniato dalla recente pubblicazione del “Documento di Madrid – New Delhi” redatto dall’ICOMOS. Vengono analizzati i caratteri peculiari del restauro del Moderno, trovando punti di unione e di divergenza con il restauro tradizionale dell’architettura. In particolare, ci si concentra sulla descrizione delle attuali tecnologie in uso per il restauro dei materiali cementizi storici e sulle problematiche connesse alla scarsa considerazione di cui ancora godono tali materiali nell’ambito del restauro dell’architettura. In tale contesto, i trattamenti fotocatalitici sviluppati si propongono come soluzioni per la conservazione delle superfici architettoniche cementizie con pregio decorativo. Vista la scarsa presenza in letteratura di applicazioni a base di TiO2 su substrati cementizi, sono stati messi a punto alcuni trattamenti innovativi che vedono la dispersione di nanoparticelle di TiO2 in matrici inorganiche di silicato di etile e idrossiapatite. Tali consolidanti sono tra i più affermati nell’ambito del restauro dei materiali e la loro compatibilità con i substrati cementizi è stata attestata da precedenti studi. I trattamenti così elaborati vengono valutati in termini di efficacia autopulente e compatibilità coi substrati.

Metodologie avanzate per l'ottimizzazione dell'assemblaggio di una pompa carburante per automotive

Il seguente elaborato è il frutto del lavoro di tirocinio svolto in Marelli. L'obiettivo del tirocinio è stato il miglioramento del processo di produzione della Pompa Tender. Questa è la pompa di alimentazione benzina per cui Marelli ha vinto la concessione per diventare unico fornitore per tutte le scuderie partecipanti alle gare di formula 1. Il mondo Motorsport rappresenta un ambiente competitivo dove ogni singolo componente delle auto deve garantire le massime prestazioni ed essere affidabile. La massima cura nella produzione è un requisito minimo per diventare fornitori di questa realtà. Per questo Marelli ha deciso di mettere in dubbio il suo processo di fabbricazione cercando un occhio esterno che potesse mettere a nudo eventuali difetti di produzione. Il miglioramento di processo è stato perseguito analizzando ogni operazione in ottica di Lean Manufacturing. Il lavoro è partito con l'analisi del tempo ciclo di produzione accompagnata dalla rilevazione di Muda e verifiche sul corretto approvvigionamento di materiali e accertamenti sulla funzionalità del layout di stabilimento. Dopo le analisi del caso, sono state prese scelte di miglioramento che vanno dal riadattamento del Layout, eliminazione di colli di bottiglia, modifica sulle fasi di processo, riorganizzazione degli strumenti di lavoro sui banchi di assemblaggio ed eliminazione di cause di contaminazione all'interno della pompa. Questo ha permesso di ridurre il tempo ciclo di produzione del componente e di conseguenza diminuire la saturazione dell'operatore. Inoltre, successivamente si è fatto un lavoro di standardizzazione su tutte le pompe dello stesso tipo prodotte nello stabilimento. Grazie a questa standardizzazione si può parlare adesso di famiglia di pompe ed esse non vengono più trattate singolarmente.