Analisi termiche sull'impiego di materiali a cambiamento di fase (PCM) nelle pavimentazioni stradali

Il presente lavoro di tesi mira a studiare l’utilizzo di aggregati artificiali (PLA) costituiti da aggregati leggeri (LWA) impregnati di materiali a cambiamento di fase (Phase-Change Materials, PCM) nei conglomerati bituminosi. L’obiettivo della tesi è quello di dimostrare che l’utilizzo di questi materiali nelle sovrastrutture stradali, grazie alla proprietà di cambiare fase (da solida a liquida e viceversa) in funzione della temperatura, induce una liberazione di calore. La conseguenza immediata dell’utilizzo di questi materiali è la ridotta necessità di manutenzione invernale, abbattendo i costi di ripristino della pavimentazione. Inoltre l’utilizzo di PLA non deve pregiudicare l’aspetto prestazionale e la vita utile dell’infrastruttura.

Development and scale-up studies of bio-based poly(ester-amide)s

Plastics are polymers of conventional and extensive use in our day-to-day life. This is due to their light weight, adaptability to different uses and low prices. A downside of such extensive use is the environmental pollution arising from plastic production and disposal. Indeed, many commodity polymers are produced from non-renewable resources while other do not bio-degrade after their end-of-life disposal. Consequently, the ideal polymer comes from renewable raw materials and bio-degrades after its disposal, meaning that it would do little or no harm to the environment from the beginning to the end of its life cycle. In this thesis project a class of bio-based and bio-degradable co-polymers, namely poly(ester-amide)s, was investigated because of their tunable mechanical and bio-degradation properties as well as their renewable origin. Such polymers were synthetized and characterized thermically and mechanically. Furthermore, a scale-up procedure was developed and applied to one polymer and processing trials were made with the material obtained after scale-up.

Design of alternative energy storage systems for hybrid vehicles based on statistical processing of driving cycles information

Hybrid vehicles represent the future for automakers, since they allow to improve the fuel economy and to reduce the pollutant emissions. A key component of the hybrid powertrain is the Energy Storage System, that determines the ability of the vehicle to store and reuse energy. Though electrified Energy Storage Systems (ESS), based on batteries and ultracapacitors, are a proven technology, Alternative Energy Storage Systems (AESS), based on mechanical, hydraulic and pneumatic devices, are gaining interest because they give the possibility of realizing low-cost mild-hybrid vehicles. Currently, most literature of design methodologies focuses on electric ESS, which are not suitable for AESS design. In this contest, The Ohio State University has developed an Alternative Energy Storage System design methodology. This work focuses on the development of driving cycle analysis methodology that is a key component of Alternative Energy Storage System design procedure. The proposed methodology is based on a statistical approach to analyzing driving schedules that represent the vehicle typical use. Driving data are broken up into power events sequence, namely traction and braking events, and for each of them, energy-related and dynamic metrics are calculated. By means of a clustering process and statistical synthesis methods, statistically-relevant metrics are determined. These metrics define cycle representative braking events. By using these events as inputs for the Alternative Energy Storage System design methodology, different system designs are obtained. Each of them is characterized by attributes, namely system volume and weight. In the last part the work, the designs are evaluated in simulation by introducing and calculating a metric related to the energy conversion efficiency. Finally, the designs are compared accounting for attributes and efficiency values. In order to automate the driving data extraction and synthesis process, a specific script Matlab based has been developed. Results show that the driving cycle analysis methodology, based on the statistical approach, allows to extract and synthesize cycle representative data. The designs based on cycle statistically-relevant metrics are properly sized and have satisfying efficiency values with respect to the expectations. An exception is the design based on the cycle worst-case scenario, corresponding to same approach adopted by the conventional electric ESS design methodologies. In this case, a heavy system with poor efficiency is produced. The proposed new methodology seems to be a valid and consistent support for Alternative Energy Storage System design.

Ingegnerizzazione e design di nanoparticelle core-shell di magnetite/silice

In the past decade the study of superparamagnetic nanoparticles has been intensively developed for many biomedical applications such as magnetically assisted drug delivery, MRI contrast agents, cells separation and hyperthermia therapy. All of these applications require nanoparticles with high magnetization, equipped also with a suitable surface coating which has to be non-toxic and biocompatible. In this master thesis, the silica coating of commercially available magnetic nanoparticles was investigated. Silica is a versatile material with many intrinsic features, such as hydrophilicity, low toxicity, proper design and derivatization yields particularly stable colloids even in physiological conditions. The coating process was applied to commercial magnetite particles dispersed in an aqueous solution. The formation of silica coated magnetite nanoparticles was performed following two main strategies: the Stöber process, in which the silica coating of the nanoparticle was directly formed by hydrolysis and condensation of suitable precursor in water-alcoholic mixtures; and the reverse microemulsions method in which inverse micelles were used to confine the hydrolysis and condensation reactions that bring to the nanoparticles formation. Between these two methods, the reverse microemulsions one resulted the most versatile and reliable because of the high control level upon monodispersity, silica shell thickness and overall particle size. Moving from low to high concentration, within the microemulsion region a gradual shift from larger particles to smaller one was detected. By increasing the amount of silica precursor the silica shell can also be tuned. Fluorescent dyes have also been incorporated within the silica shell by linking with the silica matrix. The structure of studied nanoparticles was investigated by using transmission electron microscope (TEM) and dynamic light scattering (DLS). These techniques have been used to monitor the syntetic procedures and for the final characterization of silica coated and silica dye doped nanoparticles. Finally, field dependent magnetization measurements showed the magnetic properties of core-shell nanoparticles were preserved. Due to a very well defined structure that combines magnetic and luminescent properties together with the possibility of further functionalization, these multifunctional nanoparticles are potentially useful platforms in biomedical fields such as labeling and imaging.

Simulation of visible light communications in vehicular networks

The rapid development in the field of lighting and illumination allows low energy consumption and a rapid growth in the use, and development of solid-state sources. As the efficiency of these devices increases and their cost decreases there are predictions that they will become the dominant source for general illumination in the short term. The objective of this thesis is to study, through extensive simulations in realistic scenarios, the feasibility and exploitation of visible light communication (VLC) for vehicular ad hoc networks (VANETs) applications. A brief introduction will introduce the new scenario of smart cities in which visible light communication will become a fundamental enabling technology for the future communication systems. Specifically, this thesis focus on the acquisition of several, frequent, and small data packets from vehicles, exploited as sensors of the environment. The use of vehicles as sensors is a new paradigm to enable an efficient environment monitoring and an improved traffic management. In most cases, the sensed information must be collected at a remote control centre and one of the most challenging aspects is the uplink acquisition of data from vehicles. My thesis discusses the opportunity to take advantage of short range vehicle-to-vehicle (V2V) and vehicle-to-roadside (V2R) communications to offload the cellular networks. More specifically, it discusses the system design and assesses the obtainable cellular resource saving, by considering the impact of the percentage of vehicles equipped with short range communication devices, of the number of deployed road side units, and of the adopted routing protocol. When short range communications are concerned, WAVE/IEEE 802.11p is considered as standard for VANETs. Its use together with VLC will be considered in urban vehicular scenarios to let vehicles communicate without involving the cellular network. The study is conducted by simulation, considering both a simulation platform (SHINE, simulation platform for heterogeneous interworking networks) developed within the Wireless communication Laboratory (Wilab) of the University of Bologna and CNR, and network simulator (NS3). trying to realistically represent all the wireless network communication aspects. Specifically, simulation of vehicular system was performed and introduced in ns-3, creating a new module for the simulator. This module will help to study VLC applications in VANETs. Final observations would enhance and encourage potential research in the area and optimize performance of VLC systems applications in the future.

Collection and real-time analysis of images from aircraft to support civil protection operational activities

This report describes the realization of a system, in which an object detection model will be implemented, whose aim is to detect the presence of people in images. This system could be used for several applications: for example, it could be carried on board an aircraft or a drone. In this case, the system is designed in such a way that it can be mounted on light/medium weight helicopters, helping the operator to find people in emergency situations. In the first chapter the use of helicopters for civil protection is analysed and applications similar to this case study are listed. The second chapter describes the choice of the hardware devices that have been used to implement a prototype of a system to collect, analyse and display images. At first, the PC necessary to process the images was chosen, based on the characteristics of the algorithms that are necessary to run the analysis. In the further, a camera that could be compatible with the PC was selected. Finally, the battery pack was chosen taking into account the electrical consumption of the devices. The third chapter illustrates the algorithms used for image analysis. In the fourth, some of the requirements listed in the regulations that must be taken into account for carrying on board all the devices have been briefly analysed. In the fifth chapter the activity of design and modelling, with the CAD Solidworks, the devices and a prototype of a case that will house them is described. The sixth chapter discusses the additive manufacturing, since the case was printed exploiting this technology. In the seventh chapter, part of the tests that must be carried out on the equipment to certificate it have been analysed, and some simulations have been carried out. In the eighth chapter the results obtained once loaded the object detection model on a hardware for image analyses were showed. In the ninth chapter, conclusions and future applications were discussed.

Study and characterization of low molecular weight polymer solutions for application in lubricating oils

The aim of this thesis is to evaluate the possibility of using short linear polymer chains as additives in lubricating oil applications. Through previous works, it has been seen that they are particularly resistant to mechanical degradation, which is the main reason why lubricating oils need to be changed after a while. This is the main reason why they could be proposed as alternatives in the market. The results of this work have been split into two major phases: the first concentrated on characterizing a target product obtained through thermal degradation, starting from the original long chain parent polymer, and the second focused on the technological advancement of heat exchangers. Through the studies carried out, we’ve characterized our innovative polymers and the solutions made with them and base oil at different concentrations. The most promising result is that these short random coiled polymeric chains obey to a more general universal function which express the value of specific viscosity as function of a dimensionless quantity c/c*. For the design of the unit operation, several alternatives were proposed and these all shared the same final goal: cooling the polymer without the presence of oxygen to avoid oxidation and formation of unwanted substances. We’ve analyzed the main difficulties related to the presence of these highly viscous substances and, more importantly, how to deal with this situation (e.g. by considering radial static mixer or even more complex conformations).

"SYN feel light": Progetto di un sistema di illuminazione sinestetico per il miglioramento dell'esperienza ristorativa

La tesi nasce dalla collaborazione con GOLDèlite, una recente startup di Bologna specializzata nella progettazione e realizzazione di prodotti di design impiegando un materiale antibatterico brevettato. Un approccio multidisciplinare e la contaminazione di più e diverse competenze ha dato vita all’intero progetto che ha portato alla risposta ad una complessità contemporanea con la creazione di un prodotto adattato ad un ambiente innovativo. Il progetto prevede la realizzazione della lampada SYN feel light capace di incrementare esperienze sensoriali, trasformando i suoni in colori abbinati ad aromi, regalando così un’atmosfera suggestiva ideale pensata per ristoranti ricercati. Il concept riprende le linee eleganti e raffinate di un ristorante stellato, legando il know-how aziendale e la tecnologia di Area3 e Indico Technologies, aziende che operano in diversi campi scientifici volti al benessere fisico e mentale. Alla base di tale progettazione, vi è una panoramica su un particolare e poco noto fenomeno percettivo capace di unire più sfere sensoriali: la sinestesia. Analizzando teorie neuroscientifiche e studi sul fenomeno, si è poi ricercato il suo impiego in ambienti della quotidianità ed è stata realizzata una collezione di casi studio che sfruttano la multisensorialità delle sinestesie per incrementare le esperienze sensoriali e il benessere. L’obiettivo della tesi è mostrare lo sviluppo di un artefatto capace di stimolare i 5 sensi durante esperienze gastronomiche, dimostrando come esso migliori tali esperienze e porti allo sviluppo di nuove sinestesie. Inoltre, l’allenamento di tali fenomeni può portare a diversi benefici per la salute delle persone. Il progetto è arrivato alla fase di prototipazione e la successiva prova sul campo seguendo quelli che sono gli stadi precedenti all’entrata sul mercato, obiettivo prefissato dell’azienda con il quale la lampada SYN feel light si evolverà.

Design and implementation of a synchronous interleaved boost converter for fuel cell-powered catamaran

The present work describes the different stages of design, implementation, and validation procedures for an interleaved DC-DC boost converter intended for the 2022 Futura, a fuel cell-powered racing catamaran developed by the UniBoAT team. The main goal of the entire design has been the significant reduction of the weight of the converter by removing heat sinks and reducing component size while increasing its efficiency by adopting high-end power switches and the interleaved architecture operated with a synchronous control strategy. The obtained converter has been integrated into the structure containing the fuel cell stack obtaining a fully integrated system. The realized device has been based on an interleaved architecture with six phases controlled digitally through the average current mode control. The design has been validated through simulations carried out using the software LT-Spice, whereas experimental validations have been performed by means of laboratory bench tests and on-field tests. Detailed thermal and efficiency analyses are provided with the bench tests under the two synchronous and non-synchronous operating modes and with the adoption of the phase shedding technique. The prototype implementation and its performance in real operating conditions are also discussed. Eventually, it is underlined as the designed converter can be used in other applications requiring a voltage-controlled boost converter.

Design, fabrication and mechanical characterization of a structural node made using Wire and Arc Additive Manufacturing (WAAM) technology

Additive Manufacturing (AM), also known as “3D printing”, is a recent production technique that allows the creation of three-dimensional elements by depositing multiple layers of material. This technology is widely used in various industrial sectors, such as automotive, aerospace and aviation. With AM, it is possible to produce particularly complex elements for which traditional techniques cannot be used. These technologies are not yet widespread in the civil engineering sector, which is slowly changing thanks to the advantages of AM, such as the possibility of realizing elements without geometric restrictions, with less material usage and a higher efficiency, in particular employing Wire-and-Arc Additive Manufacturing (WAAM) technology. Buildings that benefit most from AM are all those structures designed using form-finding and free-form techniques. These include gridshells, where joints are the most critical and difficult elements to design, as the overall behaviour of the structure depends on them. It must also be considered that, during the design, the engineer must try to minimize the structure's own weight. Self-weight reductions can be achieved by Topological Optimization (TO) of the joint itself, which generates complex geometries that could not be made using traditional techniques. To sum up, weight reductions through TO combined with AM allow for several potential benefits, including economic ones. In this thesis, the roof of the British Museum is considered as a case study, analysing the gridshell structure of which a joint will be chosen to be designed and manufactured, using TO and WAAM techniques. Then, the designed joint will be studied in order to understand its structural behaviour in terms of stiffness and strength. Finally, a printing test will be performed to assess the production feasibility using WAAM technology. The computational design and fabrication stages were carried out at Technische Universität Braunschweig in Germany.