Studio e controllo della velocità di fasciatura di balle cilindriche in avvolgitori per agricoltura

Studio e analisi della velocità di fasciatura di balle cilindriche con il film plastico negli avvolgitori utilizzati in agricoltura. In particolare è stato studiato un meccanismo che potesse garantire il corretto funzionamento ad elevate velocità di avvolgitura evitando che il film plastico subisca eccessivi tensionamenti o che giunga a rottura. Il lavoro ha previsto numerosi test e rilevamenti di velocità che hanno prodotto risultati positivi e utili ai fini di uno studio futuro più dettagliato.

In situ real-time investigation of Organic Ultra-Thin-Film transistors: growth, electrical properties and biosensing applications

Organic electronics has grown enormously during the last decades driven by the encouraging results and the potentiality of these materials for allowing innovative applications, such as flexible-large-area displays, low-cost printable circuits, plastic solar cells and lab-on-a-chip devices. Moreover, their possible field of applications reaches from medicine, biotechnology, process control and environmental monitoring to defense and security requirements. However, a large number of questions regarding the mechanism of device operation remain unanswered. Along the most significant is the charge carrier transport in organic semiconductors, which is not yet well understood. Other example is the correlation between the morphology and the electrical response. Even if it is recognized that growth mode plays a crucial role into the performance of devices, it has not been exhaustively investigated. The main goal of this thesis was the finding of a correlation between growth modes, electrical properties and morphology in organic thin-film transistors (OTFTs). In order to study the thickness dependence of electrical performance in organic ultra-thin-film transistors, we have designed and developed a home-built experimental setup for performing real-time electrical monitoring and post-growth in situ electrical characterization techniques. We have grown pentacene TFTs under high vacuum conditions, varying systematically the deposition rate at a fixed room temperature. The drain source current IDS and the gate source current IGS were monitored in real-time; while a complete post-growth in situ electrical characterization was carried out. At the end, an ex situ morphological investigation was performed by using the atomic force microscope (AFM). In this work, we present the correlation for pentacene TFTs between growth conditions, Debye length and morphology (through the correlation length parameter). We have demonstrated that there is a layered charge carriers distribution, which is strongly dependent of the growth mode (i.e. rate deposition for a fixed temperature), leading to a variation of the conduction channel from 2 to 7 monolayers (MLs). We conciliate earlier reported results that were apparently contradictory. Our results made evident the necessity of reconsidering the concept of Debye length in a layered low-dimensional device. Additionally, we introduce by the first time a breakthrough technique. This technique makes evident the percolation of the first MLs on pentacene TFTs by monitoring the IGS in real-time, correlating morphological phenomena with the device electrical response. The present thesis is organized in the following five chapters. Chapter 1 makes an introduction to the organic electronics, illustrating the operation principle of TFTs. Chapter 2 presents the organic growth from theoretical and experimental points of view. The second part of this chapter presents the electrical characterization of OTFTs and the typical performance of pentacene devices is shown. In addition, we introduce a correcting technique for the reconstruction of measurements hampered by leakage current. In chapter 3, we describe in details the design and operation of our innovative home-built experimental setup for performing real-time and in situ electrical measurements. Some preliminary results and the breakthrough technique for correlating morphological and electrical changes are presented. Chapter 4 meets the most important results obtained in real-time and in situ conditions, which correlate growth conditions, electrical properties and morphology of pentacene TFTs. In chapter 5 we describe applicative experiments where the electrical performance of pentacene TFTs has been investigated in ambient conditions, in contact to water or aqueous solutions and, finally, in the detection of DNA concentration as label-free sensor, within the biosensing framework.

Effetti della viscoelasticità sulla misura dell’energia di adesione tra film di polietilene

Lo stretch film è una diffusa applicazione per imballaggio dei film in polietilene (PE), utilizzato per proteggere diversi prodotti di vari dimensioni e pesi. Una caratteristica fondamentale del film è la sua proprietà adesiva in virtù della quale il film può essere facilmente chiuso su se stesso. Tipicamente vengono scelti gradi lineari a bassa densità (LLDPE) con valori relativamente bassi di densità a causa delle loro buone prestazioni. Il mercato basa la scelta del materiale adesivo per tentativi piuttosto che in base alla conoscenza delle caratteristiche strutturali ottimali per l’applicazione. Come per i pressure sensitive adhesives, le proprietà adesive di film stretch in PE possono essere misurati mediante "peel testing". Esistono molti metodi standard internazionali ma i risultati di tali prove sono fortemente dipendenti dalla geometria di prova, sulla possibile deformazione plastica che si verificano nel peel arm(s), e la velocità e temperatura. Lo scopo del presente lavoro è quello di misurare l'energia di adesione Gc di film stretch di PE, su se stessi e su substrati diversi, sfruttando l'interpretazione della meccanica della frattura per tener conto dell'elevata flessibilità e deformabilità di tali film. Quindi, la dipendenza velocità/temperatura di Gc sarà studiata con riferimento diretto al comportamento viscoelastico lineare dei materiali utilizzati negli strati adesivi, per esplorare le relazioni struttura-proprietà che possono mettere in luce i meccanismi molecolari coinvolti nei processi di adesione e distacco. Nella presente caso, l’adesivo non è direttamente disponibile come materiale separato che può essere messo tra due superfici di prova e misurato per la determinazione delle sue proprietà. Il presupposto principale è che una parte, o fase, della complessa struttura semi-cristallina del PE possa funzionare come adesivo, e un importante risultato di questo studio può essere una migliore identificazione e caratterizzazione di questo "fase adesiva".

Investigation of RuO2/Ta2O5 thin film evolution by thermogravimetry combined with mass spectrometry

The thermal evolution process of RuO2–Ta2O5/Ti coatings with varying noble metal content has been investigated under in situ conditions by thermogravimetry combined with mass spectrometry. The gel-like films prepared from alcoholic solutions of the precursor salts (RuCl3·3H2O, TaCl5) onto titanium metal support were heated in an atmosphere containing 20% O2 and 80% Ar up to 600 °C. The evolution of the mixed oxide coatings was followed by the mass spectrometric ion intensity curves. The cracking of retained solvent and the combustion of organic surface species formed were also followed by the mass spectrometric curves. The formation of carbonyl- and carboxylate-type surface species connected to the noble metal was identified by Fourier transform infrared emission spectroscopy. These secondary processes–catalyzed by the noble metal–may play an important role in the development of surface morphology and electrochemical properties. The evolution of the two oxide phases does not take place independently, and the effect of the noble metal as a combustion catalyst was proved.

At breaking point? Challenges for Australian film policy through the lens of genre (horror) films

Cultural policy settings attempting to foster the growth and development of the Australian feature film industry in era of globalisation are coming under increasing pressure. Global forces and emerging production and distribution models are challenging the “narrowness” of cultural policy – mandating a particular film culture, circumscribing certain notions of value and limiting the variety of films produced through cultural policy driven subvention models. Australian horror film production is an important case study. Horror films are a production strategy well suited to the financial limitations of the Australian film industry with competitive advantages for producers against international competitors. However, emerging within a “national” cinema driven by public subsidy and social/cultural objectives, horror films – internationally oriented with a low-culture status – have been severely marginalised within public funding environments. This paper introduces Australian horror film production, and examines the limitations of cultural policy, and the impacts of these questions for the Producer Offset.

Learning through collaboration and co-production in the Singapore film industry : opportunities for development

Co-production and strategic partnerships may generate valuable learning opportunities for firms to access to the knowledge and expertise of their partners. Such sharing and transfer of knowledge has become an increasingly common way for organising corporate finance and resources. However, not all collaborations result in a net positive experience for both partners. It can be a zero-sum game in which the partner learning the fastest dominates the relationship. In some cases, failure to gain access to partner knowledge results in unequal benefits accruing from such alliances. By examining the Singapore film industry from a learning perspective and taking into account particular forms of alliances, the study contributes to our understanding of the potential benefit and challenges of coproduction as a strategy for development.

Multi-level order, friction and contradiction : the evolution of Australian film industry policy

Cultural policy studies have previously highlighted the importance of multiple logics, friction and contradiction in cultural policy. Recent developments in institutional theory provide a framework for analysing change in cultural policy which explores movement between these multiple and sometimes contradictory logics. This paper analyses the role of friction in the evolution of Australian film industry policy and in particular the tension between competing logics regarding nationalism, commercialism and the state. The paper is suggestive of the relevance of institutional theory as a framework for understanding cultural policy evolution.

Film Festivals

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Rates of change : digital distribution as a disruptive technology in the film industry

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