L'oxyde thermoélectrique (TE) Ca3Co4O9 se place avantageusement pour les applications de conversion d'énergie en raison de ses bonnes propriétés TE, ses stabilités chimique et thermique à l'air à haute température et l'absence de biotoxicité. Une étude comparative des apports respectifs de procédés de consolidation (frittage conventionnel-CS, pressage à chaud-HP et frittage flash-SPS) a été menée pour déterminer les conditions expérimentales d'obtention de céramiques Ca3Co4O9 aux caractéristiques TE et fiabilité optimisées pour être intégrées dans des dispositifs TE. Par le procédé HP, les conditions optimales (920°C, 30 MPa, 24 h) ont permis d'élaborer des matériaux denses (96 %) et fortement texturés, avec un maxima de pôles {001} de 22 mrd et une croissance notable des grains dans les plans (a,b). Il en découle une faible résistivité ab (5.25 m.cm à 900 K) et donc un facteur de puissance PFab remarquable (595 µW.m-1.K-2). Les caractéristiques mécaniques sont considérablement améliorées en comparaison avec la céramique CS. Des céramiques plus denses (99.6 %) ont été élaborées dans des temps très courts par SPS, mais avec une faible texture. PFab est plus faible que celui obtenu par HP. Les propriétés mécaniques sont toutefois meilleures. D'autre part, des matériaux Ca3Co4O9 multicouches ont été élaborés et les propriétés TE obtenues sont anisotropes. L'anisotropie de la résistivité c/ab vaut 13.5 dans la plage 0-350 K, mais diminue au-delà de 350 K et avoisine 8.8 à 900 K. L'anisotropie PFab/PFc vaut 12 à 900 K. La conductivité thermique abest plus élevée que c. Le facteur de mérite est plus élevé dans les plans (a,b), avec ZTab = 0.16 à 900 K et (ZTab/ ZTc) = 4.6.

Des apatites nanocristallines biomimétiques (ANB), de formule Ca10-x-Z(PO4)6-x(HPO4)x(OH)2-x-2Z, (H2O)n, ont été synthétisées par précipitation en milieu aqueux puis consolidées par frittage flash (Spark Plasma Sintering, SPS). Elles sont composées de nanocristaux munis d'un coeur apatitique entouré d'une couche phosphocalcique hydratée de surface contenant des ions phosphate, hydrogénophosphate et calcium "non-apatitiques" mobiles et facilement échangeables, qui leur confère une forte réactivité. La composition chimique, la structure et la morphologie des nanocristaux synthétisés évoluent avec le vieillissement en solution et ils tendent vers une plus grande stabilité thermodynamique. Bien que la teneur en espèces chimiques non-apatitiques diminue dans la couche hydratée, leur présence reste importante même après une longue maturation. Le procédé de frittage par SPS à basse température (150°C) de ces ANB a permis d'élaborer des céramiques poreuses fortement cohésives. Le phénomène de frittage ainsi observé suggère une consolidation de type "fusion cristalline" qui met à contribution la forte réactivité de surface des nanocristaux via leur couche hydratée de surface. Le module d'élasticité (12 à 35 GPa) et la résistance à la rupture en flexion (environ 10 MPa) de ces céramiques sont voisins de ceux du minéral osseux. De plus, la taille nanométrique des cristaux, bénéfique à la biorésorption après implantation en site osseux, et la présence d'espèces ioniques nonapatitiques mobiles favorable à la bioactivité sont préservées après SPS. Ces propriétés offrent aux céramiques d'ANB un potentiel particulièrement intéressant pour des applications en ingénierie tissulaire osseuse.

Tungsten (W) based materials can be used in fusion reactors due to several advantages. Different fabrication routes can be applied to develop tungsten materials with intended microstructure and properties for specific application including nanostructured grades. Therein, innovative chemical routes are unique in their approach owing numerous benefits. This thesis summarizes the development of W-based composites dispersed-strengthened by rare earth (RE) oxides and their evaluation for potential application as plasma facing armour material to be used in fusion reactor. Final material development was carried out in two steps; a) fabrication of nanostructured metallic tungsten powder dispersed with RE-oxides and b) powder sintering into bulk oxide-dispersed strengthened (ODS) composite by spark plasma process. With the help of advanced characterization tools applied at intermediate and final stages of the material development, powder fabrication and sintering conditions were optimized. The aim was to achieve a final material with a homogenous fine microstructure and improved properties, which can withstand under extreme conditions of high temperature plasma. Two groups of starting materials, synthesized via novel chemical methods, having different compositions were investigated. In the first group, APT-based powders doped with La or Y elements in similar ways, had identical particles’ morphology (up to 70 μm). The powders were processed into nanostructured composite powders under different reducing conditions and were characterized to investigate the effects on powder morphology and composition. The properties of sintered tungsten materials were improved with dispersion of La2O3 and Y2O3 in the respective order. The oxide dispersion was less homogeneous due to the fact that La or Y was not doped into APT particles. The second group, Ydoped tungstic acid-based powders synthesized through entirely different chemistry, contained nanocrystalline particles and highly uniform morphology. Hydrogen reduction of doped-tungstic acid compounds is complex, affecting the morphology and composition of the final powder. Hence, processing conditions are presented here which enable the separation of Y2O3 phase from Y-doped tungstic acid. Nevertheless, the oxide dispersion reduces the sinterability of tungsten powders, the fabricated nanostructured W-Y2O3 powders were sinterable into ultrafine ODS composites at temperatures as low as 1100 °C with highly homogeneous nano-oxide dispersion at W grain boundaries as well as inside the grain. The SPS parameters were investigated to achieve higher density with optimum finer microstructure and higher hardness. The elastic and fracture properties of the developed ODS-W have been investigated by micro-mechanical testing to estimate the materials’ mechanical response with respect to varying density and grain size. In contrast from some literature results, coarse grained ODS-W material demonstrated better properties. The developed ODS material with 1.2 Y2O3 dispersion were finally subjected to high heat flux tests in the electron beam facility “JUDITH-1”. The samples were loaded under ELM-like thermal-shocks at varying base temperatures up to an absorbed power density of 1.13 GW/m2, for armour material evaluation. Post mortem characterizations and comparison with other reference W grades, suggest lowering the oxide contents below 0.3 wt. % Y2O3. As an overview of the study conducted, it can be concluded that innovative chemical routes can be potential replacement to produce tungsten based materials of various composition and microstructure, for fusion reactor applications. The methods being cheap and reproducible, are also easy to handle for large production at industrial scale. / <p>QC 20120827</p>

Inorganic porous materials are widely used in a number of applications, where is a need to functionalize and produce materials with a multiscale porosity. The first part of the thesis describes how a novel and facile powder processing approach, using pulsed current processing (PCP) or, as it is commonly called, spark plasma sintering (SPS), has been employed to produce mechanically stable, hierarchically porous bodies from different porous powders. Surfactant-templated mesoporous spheres were PCP-treated to yield meso/macro porous monoliths. The bimodal pore size can be tailored by choice of templating molecules in the aerosol-assisted synthesis process and by the particle size of the spheres. Diatomite powders were used to produce macro/macroporous monoliths. The densification behaviour of this inexpensive and renewable macroporous raw material was evaluated in detail, and an optimum temperature range was identified where the PCP process yields mechanically strong monoliths. Binder-less, hierarchically porous zeolite monoliths were produced from various zeolite powders, e.g. silicalite-1, ZSM-5 and zeolite Y. Line-broadening analysis of X-ray powder diffraction data by the Rietveld method and electron microscopy showed that the formation of strong interparticle bonds during the PCP process is associated with a local amorphization reaction that is induced by the high contact stress and temperature. Xylene isomerisation studies showed that binder-less ZSM-5 monoliths display a high catalytic selectivity. Direct (in-situ) nanoparticle functionalization of surfactant templated mesoporous silica particles has also been demonstrated. Pre-synthesized TiO2 nanoparticles were dispersed in a precursor solution, containing surfactant and silica source, and processed in an aerosol-generator to produce spherical nanoparticle-functionalized mesoporous particles.

Lo studio analizza la relazione tra i diversi prezzi delle droghe illegali, eroina e cocaina, e il livello di violenza sistemica in un territorio. L'ipotesi dello studio è che ad un aumento dei prezzi delle droghe illegali, si registra una maggiore violenza causata dal maggiore ritorno economico derivante dalla commissione della violenza. L'analisi empirica si riferisce agli anni ottanta e novanta negli Stati Uniti d'America. Lo studio di mostra la validità dell'ipotesi e propone nuove ambiti di ricerca. / The study analyzes the relation between the different prices of illegal drugs, heroin and cocaine, and the level of systemic violence recorded in a territory. The hypothesis of the study is that from an increase of the prices of illegal drugs, it is derived a greater level of violence caused by the greater menotary return derived by the commission of violence. The empirical analysis referred to the eighties and nineties in the United States of America. The study demonstrates the hypothesis and proposes new research paths.

Questa tesi esplora il problema della contraffazione degli accessori moda di lusso allo scopo di capire le opportunità criminali che derivano dalle vulnerabilità del settore. Viene fornita prima una panoramica della contraffazione nel settore moda al fine di descrivere le caratteristiche principali del mercato illegale. Allo scopo di approfondire la conoscenza del fenomeno e delle opportunità criminali create dal mercato legale, viene quindi analizzata la struttura e il funzionamento del settore applicando la metodologia sviluppata dal centro di ricerca IRCP, la Methodology for and Assessment of the Vulnerability of Markets. Le domande principali a cui questa tesi vuole rispondere sono: - Quanto è vulnerabile il mercato italiano degli accessori moda di lusso alla contraffazione? - A quali fattori è imputabile la vulnerabilità alla contraffazione delle imprese italiane del settore moda? / This thesis is concerned with the problem of counterfeiting of leather luxury fashion goods and it is aimed at understanding the opportunities to crime produced by the vulnerabilities of this sector. First, it provides an overview of fashion counterfeiting trying to describe what the main features of the illegal market are. Then, in order to acquire a deeper knowledge of the phenomenon and of the opportunities arising in the legal market for the carrying out of illegal activities it analyses the structure and functioning of the sector in order to identify its vulnerabilities to this crime by applying the methodology for licit market scanning developed by the IRCP, the Methodology for and Assessment of the Vulnerability of Markets. The main questions this thesis wants to answer are: - To what extent are Italian luxury fashion companies vulnerable to counterfeit products? - To what factors can be ascribed to the vulnerability to counterfeiting of Italian legitimate fashion companies?

La ricerca tratta il tema delle modificazioni del corpo (piercing, tatuaggio, scarificazione, chirurgia estetica) nelle sue implicazioni con la questione dell'identità di genere. Attraverso uno studio sul campo condotto con metodo etnografico e interviste in profondità, vengono indagate in chiave etnometodologica le procedure attraverso cui i soggetti elaborano ed esprimono il proprio self in relazione alle rappresentazioni sociali condivise relative alla mascolinità e alla femminilità. / This research is about body modification techniques (piercing, tattooing, scarification, aesthetic surgery) in relation to gender identity. By means of a fieldwork carried out with ethnographies and in depth interviews, procedures of elaboration and expression of individual self are investigated, via an etnomethodological approach, and in a relation to social representations of femininity and masculinity.

La tesi si inserisce nell'ambito dell'animato dibattito politico e scientifico in merito alle misure volte a supportare i soggetti più deboli nel processo di inclusione socio-lavorativa. Al centro della riflessione si situano i cambiamenti che hanno caratterizzato il mercato del lavoro negli ultimi trent'anni e le politiche di welfare sviluppate a livello nazionale e comunitario per rispondere ai nuovi rischi e bisogni dei cittadini. In particolare, si approfondiscono le politiche del mercato del lavoro, cioè tutte quelle misure e quei servizi finalizzati a supportare i lavoratori in difficoltà occupazionale. La lettura proposta è volta a comprendere il significato delle azioni di politica del lavoro, alla luce dei cambiamenti introdotti dalle riforme degli ultimi anni. Si parla oggi di politiche attive del lavoro, di occupabilità, di responsabilizzazione degli individui, di personalizzazione degli interventi e, sul fronte degli attori che governano e gestiscono il sistema, di concertazione e di sinergia pubblico-privato. Nella seconda parte della tesi sono proposti due studi di caso, il modello lombardo e il modello danese di politiche del lavoro, che presentano logiche di intervento e orientamenti differenti, pur in presenza di situazioni occupazionali simili, caratterizzate da ridotti problemi di disoccupazione e da elevati tassi di partecipazione al mercato del lavoro. / The thesis is positioned within the political and scientific debate regarding the measures aimed to support the vulnerable people in the social and employment integration process. The study in depth concerns the changes of the labour market of the last thirty years and the welfare policies developed on national and European level to meet new citizens requirements. In particular, the thesis is focused on the labour market policies, which include measures and services supporting people with employment difficulties. The analysis concerns the new trends in labour market policies, the Italian model, the actors who govern the system and the types of measures (vocational guidance, vocational training, employment services, etc). The second part of thesis explores two cases, Lombardy and Denmark labour market policies models, with the analysis of different labour market problems and the various strategies to improve social cohesion and integration for disadvantaged people.

Il crime-proofing è uno strumento di prevenzione criminale promosso dalla Commissione Europea fin dal 2000. Il concetto di crime-proofing parte dall'idea che la regolamentazione dei mercati legittimi possa essere criminogenica, ossia produrre involontariamente opportunità criminali (nuove tecniche, maggiori profitti e/o minori rischi a favore dei criminali). Lo scopo è identificare queste opportunità, se presenti, ed individuare possibili strategie di contrasto. Questa tesi indaga il crime-proofing partendo da un modello di Crime Risk Assessment (CRAM) elaborato a questo scopo per la Commissione Europea. Il CRAM è stato adattato e applicato ad un fenomeno criminale di estrema attualità: la contraffazione dei marchi, con particolare riferimento al settore moda in Italia. La contraffazione è oggi una forma di economia sotterranea che ha alti impatti economici e sociali. Il settore moda è uno dei più colpiti, a causa dell'alta domanda di beni contraffatti e di basse barriere di ingresso al mercato. L'Italia è un paese leader nel mercato mondiale ed è fortemente vulnerabile alla contraffazione. Il crime risk assessment presentato in questo studio evidenzia come il quadro normativo italiano agevoli inavvertitamente l'industria della contraffazione, attraverso opportunità non previste e scappatoie nella regolazione. Obiettivo finale è quello di verificare se il crime-proofing funziona, se la metodologia attuale può essere migliorata e come questa possa essere inserita nei processi di produzione legislativa, per minimizzare il rischio di conseguenze inattese. / Crime-proofing is a crime prevention method promoted by the EU Commission since 2000. It starts from the assumption that the regulation governing legitimate sectors/markets might be criminogenic, i.e. producing unexpected opportunities for crime, in terms of new techniques, higher rewards and/or lower risk to criminals. It therefore aims at identifying such opportunities, if any, and finding out possible remedies. This thesis explores the crime-proofing approach, starting from a Crime Risk Assessment Mechanism (CRAM) that was developed to this purpose for the EU Commission. This is adapted and applied to a topical criminal phenomenon: the counterfeiting of trademarks, with special reference to the Italian fashion sector. Counterfeiting is nowadays a form of underground economy, which produces negative economic and social impacts. Fashion is one of the most affected industries, because of high consumer demand of counterfeit goods and low barriers for market entry. Italy is a leader country in the global fashion industry and is highly vulnerable to counterfeiting. The crime risk assessment undertaken in this study highlights how the Italian regulatory framework may inadvertently facilitate the counterfeiting industry, through unintended opportunities and regulatory loopholes. The ultimate goal is to check the crime-proofing functioning, whether the methodology can be improved and how it can be implemented at law-making level to minimize the risk of unexpected effects.

La presente ricerca ha analizzato il fenomeno dei blog giornalistici per rilevare se, nonostante sia impossibile riscontrare la perfetta corrispondenza tra testi di informazione ed eventi del mondo reale, l'intervento dei lettori può fare comunque in modo che si verifichi, attraverso la condivisione dei contenuti dell'informazione, un sostanziale accostamento alla verità dei fatti così come essi sono accaduti. Tutto ciò permette ai giornalisti di diffondere un'informazione più precisa, più completa e meno manipolata. Sono state discusse le ragioni del giornalismo oggettivista e quelle del giornalismo esplicativo ed è emerso come, nei blog analizzati, siano presenti due metodi diversi in grado di garantire una maggiore oggettività dell'informazione. Ciò accade perché i lettori possono interagire confrontando opinioni tra loro diverse. Dall'analisi dei post degli autori dei blog Marcello Foa e Beppe Grillo e dei relativi commenti dei loro lettori, è emerso come il valore aggiunto di questi interventi risieda nel fatto che i lettori non si rivolgono solo al giornalista, in questo caso variando di poco la dinamica, per esempio, dell'invio di lettere alla redazione, ma si rivolgono ad altri lettori per informarli o per chiedere loro spiegazioni e chiarimenti. / The research analyses the phenomenon of j-blogs to investigate if, in spite of the impossibility to achieve the perfect conformity between information about facts and facts in themselves, the participation of readers can operate, through the sharing of information contents, to assure an approach more accurate to reality and truth of events. This allows journalists to divulge an information more correct, and less manipulated. The reasons of journalism that explains facts and journalism that only describes them without any interpretation about, were equally examined. The research discovered that, in the two blogs analysed, it's possible bring out two different methods able to guarantee a major information objectivity. This occurs because readers can interact comparing different opinions. From the analysis of Marcello Foa and Beppe Grillo blogs and from their readers' comments, came out that the potential benefits of these interactions follow the possibility for readers to interact not only with journalist, in this case acting as traditional readers who, for example, send letters to the editorial staff, but also with other readers to inform them or to receive from them explanations or clarifications.