Carbonate stones on site undergo severe weathering processes, that make consolidation and protection necessary. However, currently available consolidants and protectives are far from being satisfactory when applied to this kind of materials. For this reason, in this thesis an innovative hydroxyapatite-based treatment was developed for limestone consolidation, marble consolidation and marble protection. Firstly, a new treatment protocol was set up for limestone and marble consolidation: solution precursor, concentration and pH, application method and possible additions were investigated to improve the treatment performance. Then, efficacy, compatibility and durability of the treatment were evaluated on these two lithotypes, in comparison with the products currently used for the same aim (ethyl silicate and ammonium oxalate). For marble, the treatment protocol developed in laboratory was also tested on a real historic artefact and on site. Moreover, a surface treatment for protecting marble against acidic rain was formulated, investigating how different parameters (starting solution pH and concentration, organic and inorganic additions) affect the morphology, composition and acid resistance of the treated surface. Excellent results were achieved: hydroxyapatite resulted an effective, compatible and durable consolidant for carbonate stone. Moreover, ethanol addition allowed to obtain a uniform, acid resistant protective hydroxyapatite layer on marble.

I limiti di polveri sottili in ambiente, stabiliti dall'Unione Europea, vengono attualmente superati nei periodi invernali a causa dall'impiego nel riscaldamento civile di impianti alimentati a biomassa che introducono nell'aria ambiente forti concentrazioni di polveri sottili (PM10 e PM2.5). Questo panorama è aggravato dal fatto che al momento queste caldaie sono estremamente diffuse e sfuggono alla normativa relativa alle emissioni di polvere. Gli obiettivi della tesi consistono nella progettazione, realizzazione e sperimentazione di un dispositivo per la filtrazione del particolato per le caldaie di piccola dimensione ad uso domestico. In particolare il sistema di filtrazione che si vuole ottenere deve essere caratterizzato da: elevata efficienza di filtrazione, un basso consumo energetico, un’elevata facilità di installazione per poterlo integrare anche su impianti già esistenti, una facile manutenzione. Per raggiungere gli obiettivi di progetto, nei laboratori del Dipartimento di Ingegneria Industriale, sono state allestite differenti impianti sperimentali per la valutazione di altrettante soluzioni impiantistiche, potendo così misurare la quantità di polveri sottili emesse in funzione dei parametri di esercizio. L’analisi delle prove realizzate in precedenza e dei risultati ottenuti ha permesso di procedere con la progettazione di un sistema di filtrazione che soddisfi gli obiettivi prefissati. I risultati ottenenti nelle configurazioni testate sono stati quindi utilizzati per realizzare un modello matematico che permetta di confrontare l’efficacia dei vari parametri sull'efficienza globale di cattura del particolato emesso dalla caldaia in funzione del suo carico e della sua granulometria; in questa maniera si è infine identificata una soluzione per raggiungere gli obiettivi di progetto. / The limits of fine particles in ambient, established by the European Union, are exceeded during the winter season because the use in civil heating of biomass plants introduce in ambient high level of particulate matter (PM10 and PM2.5). This panorama is aggravated by the fact that these boilers are extremely widespread and are not included in the dust emissions legislation. The target of the thesis consists in the design, implementation and testing of a device for the filtration of particulates for small size boilers for domestic use. The filtration system to be obtained must be characterized by: high filtration efficiency, low energy consumption, high simplicity of installation so to be integrate on existing systems, easy maintenance. To achieve the project’s objectives, in the laboratories of the Department of Industrial Engineering, were set up different experimental systems for the evaluation of various solutions, allowing to measure the amount of particulate emissions as a function of operating parameters. The analysis of the test performed previously and the results obtained made it possible to proceed with the design of a filtration system that meets the set objectives. The results in getting tested configurations were then used to make a mathematical model that allows to compare the effectiveness of various parameters on the overall efficiency of the particulate capture emitted from the boiler in function of its load and its particle size; in this manner is finally identified a solution to achieve the project objectives.

Este trabalho teve por objetivo desenvolver uma metodologia para fabricação cerâmica de ítria (\'Y IND.2\'O IND.3\') transparente e, em paralelo, desenvolver um sistema de aquecimento que permitisse atingir temperaturas superiores a 1800ºC. Nos últimos 5 anos, cerâmicas transparentes ganharam grande destaque e foram incluídas entre os cinco supermateriais da atualidade. A ítria - \'Y IND.2\'O IND.3\' - apresenta algumas características ópticas promissoras para fabricação de cerâmicas transparentes, dentre as quais podemos destacar: isotropia óptica e ampla faixa de transparência. Além disso, possui elevada condutividade térmica, o que confere potencialidade para aplicações em sistemas lasers de alta potência. Neste trabalho são apresentados os resultados de estudos sistemáticos relacionados à síntese, compactação e sinterização do óxido de ítria. As amostras foram sintetizadas por reação do estado sólido, usando óxido de zircônio como aditivo para o processo de sinterização. As condições de compactação das pastilhas à verde foram investigadas e permitiu a obtenção de corpos cerâmicos com densidade relativa à verde de ~55%, com uso de prensagem uniaxial seguido de prensagem isostática. As cerâmicas foram sinterizadas utilizando-se programas de temperaturas específicos sob duas condições quanto ao aquecimento: em forno elétrico e em atmosfera aberta e em forno de indução, desenvolvido nesse trabalho, em condições de vácuo dinâmico. As caracterizações físicas das amostras foram feitas por difração de raios X, microscopia eletrônica de varredura e espectroscopia óptica. Os resultados mostraram que temperaturas superiores a 1800ºC combinado com o efeito do vácuo são indispensáveis para obtenção de ítria transparente pelo método de sinterização convencional; o sistema de aquecimento desenvolvido apresentou eficiência em atingir a temperatura desejada, porém apresentou algumas limitações que impossibilitou o controle e reprodutibilidade do processo. Por meio da metodologia desenvolvida foi possível a obtenção de cerâmica de ítria com transmissão na região do visível do espectro eletromagnético (400-700 nm) de até 42%, quando comparado a um monocristal. Avançou-se na fabricação de cerâmicas transparentes, porém, ainda será necessário otimizar o controle do sistema de aquecimento do forno desenvolvido, de modo a eliminar os poucos centros espalhadores de luz existentes. / The focus of this work was to develop a methodology for manufacture of transparent Yttria (\'Y IND.2\'O IND.3\') and in addition develop a heating system that operates in temperatures above 1800ºC. In the last 5 years, transparent ceramics featured among the five supermaterials of the present. Yttria - \'Y IND.2\'O IND.3\' - presents a few optical characteristics promising to manufacture transparent ceramics, such as: optical isotropy and wide range of transparency. Besides, it has high thermal conductivity, which gives potential for applications in high power laser systems. In the work presented here, the results of a systematic study of the synthesis, compaction and sintering of yttria oxide are presented. The samples were prepared by solid state reaction, using zircon oxide as an additive to the sintering process. The compaction conditions of the green tablets were investigated and allowed the obtainment of ceramic bodies with relative density around 55%, by using uniaxial pressing followed by isostatic pressing. The ceramics were sintered using specific temperature programs under two heating conditions: electric furnace and open atmosphere and under induction furnace, developed in this work, under dynamic vacuum conditions. The physical characterizations of the samples were made by X-ray diffraction, scanning electron microscopy and optical spectroscopy. The results showed that temperatures above 1800ºC combined with the effect of vacuum are necessary to obtain transparent Yttria by conventional sintering method; the heating system developed was efficient in reaching the desired temperature, however had some limitations that prevented the control and reproducibility of the process. By means of the methodology developed it was possible to obtain ceramic yttria with transmission in the visible region of the electromagnetic spectrum (400-700) up to 42% compared to single crystal yttria. Progress was made in manufacture of transparent ceramics, however, it is necessary to optimize the control of the heating system of the furnace developed, in order to eliminate the few existing light scattering centers.

Submitted by Celso Magalhaes (celsomagalhaes@ufrrj.br) on 2018-10-03T13:33:11Z No. of bitstreams: 1 2013 - Mariane Del Carmen da Costa Diaz.pdf: 7110222 bytes, checksum: 68b29cd1489305021c7fa5e5fea95d5c (MD5) / Made available in DSpace on 2018-10-03T13:33:11Z (GMT). No. of bitstreams: 1 2013 - Mariane Del Carmen da Costa Diaz.pdf: 7110222 bytes, checksum: 68b29cd1489305021c7fa5e5fea95d5c (MD5) Previous issue date: 2013-08-08 / Instituto de Pesquisa Econ?mica Aplicada - IPEA / Esta investigaci?n de maestr?a tiene como objetivo identificar pieza de la trayectoria y la participaci?n del movimiento ind?gena en el Primer Congreso Nacional de Educaci?n Ind?gena (CONEEI) a trav?s de sus historias, recuerdos y narraciones. En el contexto actual, esta conferencia puede ser considerada un hito para garantizar, en primer lugar, la posibilidad de participaci?n de todos los grupos ?tnicos presentes en Brasil y llegar a casi todos ellos. La Conferencia es tambi?n pionera por haber permitido un espacio de car?cter nacional para discutir y reflexionar sobre las pol?ticas y objetivos de la educaci?n espec?fica. De ese modo, el CONEEI puede ser interpretada y entendida como un cambio hacia la reafirmaci?n de esos pueblos por sus luchas y el respeto a sus diferencias y particularidades, ya que proporciona espacio a las partes interesadas para analizar, reflejar su situaci?n y trazar sus perspectivas. El esquema de la investigaci?n se llev? a cabo en el sur (Rio de Janeiro, S?o Paulo, Rio Grande do Sul, Santa Catarina y Paran?) del Decreto N ? 6861 del 27 de mayo de 2009, que establece la educaci?n ind?gena, la creaci?n de los Territorios Etnoeducacionales. La investigaci?n es cualitativa y fija su metodolog?a con el apoyo de la historia oral y la narrativa perspectiva de Benjamin, para revelar una historia (narraciones ind?genas) m?s all? del oficial (documentos oficiales CONEEI), tambi?n apropiarse del concepto de memoria y penetrando a trav?s de la antropolog?a sobre el trabajo de campo mediante entrevistas y el diario de campo. A partir de los relatos de los l?deres ind?genas en el sur es posible conocer una versi?n de la conferencia desde la perspectiva de los participantes, destac?ndose principalmente la nueva organizaci?n de la pol?tica educativa para la educaci?n ind?gena (Territorios Etnoeducacionales), las dificultades y los obst?culos de la educaci?n espec?fica y el deseo de convertirse en los protagonistas de sus actividades y proyectos / A presente investiga??o de mestrado tem como objetivo identificar parte da trajet?ria e a participa??o do movimento ind?gena na I Confer?ncia Nacional de Educa??o Escolar Ind?gena (CONEEI) atrav?s de suas hist?rias, mem?rias e narrativas. No atual contexto, a referida confer?ncia pode ser considerada um marco hist?rico por garantir, pela primeira vez, a possibilidade de participa??o de todas as etnias presentes no Brasil e atingir quase que a totalidade dessas. A Confer?ncia ? pioneira tamb?m por ter possibilitado um espa?o de car?ter nacional para discutir e refletir sobre as pol?ticas e objetivos dessa educa??o espec?fica. Nesse sentido, a CONEEI pode ser interpretada e compreendida tamb?m como um direcionamento para a reafirma??o desses povos por suas lutas e respeito ?s suas diferen?as e particularidades na medida em que disponibiliza espa?o para que os envolvidos analisem, reflitam suas situa??es e tracem suas perspectivas. O recorte da pesquisa deu-se na Regi?o Sul (Rio de Janeiro, Rio Grande do Sul, Santa Catarina e Paran?) a partir do Decreto N? 6.861 de 27 de maio de 2009 que disp?e sobre a Educa??o Escolar Ind?gena, criando os Territ?rios Etnoeducacionais. A pesquisa ? qualitativa e tem sua metodologia amparada pela hist?ria oral e pela narrativa em uma perspectiva Benjaminiana, no sentido de revelar uma hist?ria (narrativas ind?genas) para al?m da oficial (documentos oficiais da CONEEI), apropriando-se tamb?m do conceito de mem?ria e perpassando pela Antropologia no que tange ? pesquisa de campo, utilizando-se entrevistas e di?rio de campo. A partir das narrativas das lideran?as ind?genas da regi?o Sul ? poss?vel conhecer uma vers?o da confer?ncia sob a ?tica desses participantes, sendo destacados principalmente a nova organiza??o de pol?tica educacional para educa??o escolar ind?gena (Territ?rios etnoeducacionais), as dificuldades e entraves desse tipo de educa??o e o desejo de se tornarem os protagonistas de suas a??es e projetos.

Nürnberg, Univ., Diplomarbeit--Erlangen, 2008.

The present dissertation aims to explore, theoretically and experimentally, the problems and the potential advantages of different types of power converters for “Smart Grid” applications, with particular emphasis on multi-level architectures, which are attracting a rising interest even for industrial requests. The models of the main multilevel architectures (Diode-Clamped and Cascaded) are shown. The best suited modulation strategies to function as a network interface are identified. In particular, the close correlation between PWM (Pulse Width Modulation) approach and SVM (Space Vector Modulation) approach is highlighted. An innovative multilevel topology called MMC (Modular Multilevel Converter) is investigated, and the single-phase, three-phase and "back to back" configurations are analyzed. Specific control techniques that can manage, in an appropriate way, the charge level of the numerous capacitors and handle the power flow in a flexible way are defined and experimentally validated. Another converter that is attracting interest in “Power Conditioning Systems” field is the “Matrix Converter”. Even in this architecture, the output voltage is multilevel. It offers an high quality input current, a bidirectional power flow and has the possibility to control the input power factor (i.e. possibility to participate to active and reactive power regulations). The implemented control system, that allows fast data acquisition for diagnostic purposes, is described and experimentally verified.

This thesis is focused on Smart Grid applications in medium voltage distribution networks. For the development of new applications it appears useful the availability of simulation tools able to model dynamic behavior of both the power system and the communication network. Such a co-simulation environment would allow the assessment of the feasibility of using a given network technology to support communication-based Smart Grid control schemes on an existing segment of the electrical grid and to determine the range of control schemes that different communications technologies can support. For this reason, is presented a co-simulation platform that has been built by linking the Electromagnetic Transients Program Simulator (EMTP v3.0) with a Telecommunication Network Simulator (OPNET-Riverbed v18.0). The simulator is used to design and analyze a coordinate use of Distributed Energy Resources (DERs) for the voltage/var control (VVC) in distribution network. This thesis is focused control structure based on the use of phase measurement units (PMUs). In order to limit the required reinforcements of the communication infrastructures currently adopted by Distribution Network Operators (DNOs), the study is focused on leader-less MAS schemes that do not assign special coordinating rules to specific agents. Leader-less MAS are expected to produce more uniform communication traffic than centralized approaches that include a moderator agent. Moreover, leader-less MAS are expected to be less affected by limitations and constraint of some communication links. The developed co-simulator has allowed the definition of specific countermeasures against the limitations of the communication network, with particular reference to the latency and loss and information, for both the case of wired and wireless communication networks. Moreover, the co-simulation platform has bee also coupled with a mobility simulator in order to study specific countermeasures against the negative effects on the medium voltage/current distribution network caused by the concurrent connection of electric vehicles.

La bonifica di acquiferi contaminati è una pratica che oggi dispone di diverse soluzioni a livello tecnologico, caratterizzate tuttavia da costi (ambientali ed economici) e problematiche tecniche di entità tale da rendere in alcuni casi poco conveniente la realizzazione dell’intervento stesso. Per questo motivo sempre maggiore interesse viene rivolto nell’ambito della ricerca alle tecnologie di bioremediation, ovvero sistemi in cui la degradazione degli inquinanti avviene ad opera di microorganismi e batteri opportunamente selezionati e coltivati. L’impiego di queste tecniche consente un minor utilizzo di risorse ed apparati tecnologici per il raggiungimento degli obiettivi di bonifica rispetto ai sistemi tradizionali. Il lavoro di ricerca presentato in questa tesi ha l’obiettivo di fornire, tramite l’utilizzo della metodologia LCA, una valutazione della performance ambientale di una tecnologia di bonifica innovativa (BEARD) e due tecnologie largamente usate nel settore, una di tipo passivo (Permeable Reactive Barrier) ed una di tipo attivo (Pump and Treat con Carboni Attivi). / At the present day, remediation of polluted groundwater can be performed through various technologies; however, these technologies are often associated with relevant costs (both economic and environmental) and technical issues which in some cases may affect the cost effectiveness and feasibility of remediation itself. This is why efforts in the field of research are being increasingly focused in the developement of bioremediation technologies which use the degrading potential of bacteria and microorganism to remove target pollutants. These technologies require a smaller demand for resources and technical equipment in order to achieve clean up targets compared to traditional systems. The aim of my research work is to provide an assessment of the environmental performance trough LCA methodology of an innovative bioremediation technology (BEARD) and two widespread remediation technologies, a Permeable Reactive Barrier (passive technology) and a Pump and treat system (active technology).

Gas separation membranes of high CO2 permeability and selectivity have great potential in both natural gas sweetening and carbon dioxide capture. Many modified PIM membranes results permselectivity above Robinson upper bound. The big problem that should be solved for these polymers to be commercialized is their aging through time. In high glassy polymeric membrane such as PIM-1 and its modifications, solubility selectivity has more contribution towards permselectivity than diffusivity selectivity. So in this thesis work pure and mixed gas sorption behavior of carbon dioxide and methane in three PIM-based membranes (PIM-1, TZPIM-1 and AO-PIM-1) and Polynonene membrane is rigorously studied. Sorption experiment is performed at different temperatures and molar fraction. Sorption isotherms found from the experiment shows that there is a decrease of solubility as the temperature of the experiment increases for both gases in all polymers. There is also a decrease of solubility due to the presence of the other gas in the system in the mixed gas experiments due to competitive sorption effect. Variation of solubility is more visible in methane sorption than carbon dioxide, which will make the mixed gas solubility selectivity higher than that of pure gas solubility selectivity. Modeling of the system using NELF and Dual mode sorption model estimates the experimental results correctly Sorption of gases in heat treated and untreated membranes show that the sorption isotherms don’t vary due to the application of heat treatment for both carbon dioxide and methane. But there is decrease in the diffusivity coefficient and permeability of pure gases due to heat treatment. Both diffusivity coefficient and permeability decreases with increasing of heat treatment temperature. Diffusivity coefficient calculated from transient sorption experiment and steady state permeability experiment is also compared in this thesis work. The results reveal that transient diffusivity coefficient is higher than steady state diffusivity selectivity.

L’oggetto principale delle attività di tesi è la caratterizzazione numerico-sperimentale di processi di colata in sabbia di ghisa sferoidale. Inizialmente è stata effettuata un’approfondita indagine bibliografica per comprendere appieno le problematiche relative all’influenza dei parametri del processo fusorio (composizione chimica, trattamento del bagno, velocità di raffreddamento) sulle proprietà microstrutturali e meccaniche di getti ottenuti e per valutare lo stato dell’arte degli strumenti numerici di simulazione delle dinamiche di solidificazione e di previsione delle microstrutture. Sono state definite, realizzate ed impiegate attrezzature sperimentali di colata per la caratterizzazione di leghe rivolte alla misura ed alla differenziazione delle condizioni di processo, in particolare le velocità di raffreddamento, ed atte a validare strumenti di simulazione numerica e modelli previsionali. Inoltre sono stati progettati ed impiegati diversi sistemi per l’acquisizione ed analisi delle temperature all’interno di getti anche di grandi dimensioni. Lo studio, mediante analisi metallografica, di campioni di materiale ottenuto in condizioni differenziate ha confermato l’effetto dei parametri di processo considerati sulle proprietà microstrutturali quali dimensioni dei noduli di grafite e contenuto di ferrite e perlite. In getti di grandi dimensioni si è riscontrata anche una forte influenza dei fenomeni di macrosegregazione e convezione della lega su microstrutture e difettologie dei getti. Le attività si sono concentrate principalmente nella simulazione numerica FEM dei processi fusori studiati e nell’impiego di modelli empirico-analitici per la previsione delle microstrutture. I dati misurati di temperature di processo e di microstrutture sono stati impiegati per la validazione ed ottimizzazione degli strumenti numerici previsionali impiegati su un ampio intervallo di condizioni di processo. L’impiego di strumenti affidabili di simulazione del processo fusorio, attraverso l’implementazione di correlazioni sperimentali microstrutture-proprietà meccaniche, permette la valutazione di proprietà e difettologie dei getti, fornendo un valido aiuto nell’ottimizzazione del prodotto finito e del relativo processo produttivo. / This work focuses on a numerical-experimental characterization of casting processes of sand ductile iron. Initially, a deep phase of literary review has been carried out in order to completely understand the effects of the process parameters (alloy chemical composition, melt treatment and cooling rates) on defects, microstructures and mechanical properties of castings and to evaluate the state of the art of the numerical instruments of simulation of solidification dynamics and microstructure prediction. Experimental casting equipments have been designed and developed in order to measure and control the cooling rates and to validate instrument of numerical simulation and microstructure prediction. Moreover, specific methods and instruments have been designed, tested and used in order to measure and analyze temperatures inside the central parts of castings, also in case of heavy sections. Metallographic samples of material, obtained with different conditions, have been studied by means of optical analysis in order to evaluate microstructural features gradient, verifying the effect of the considered process parameters on microstructures parameters such as dimension and distribution of graphite nodules and content of ferrite and pearlite. In heavy section castings, a strong influence of macrosegregation and convective phenomena on microstructures and defects was found. The main part of the activities focused on numerical simulation FEM of the performed casting processes. The measured data of temperatures and microstructures have been used for the validation and optimization of the numerical simulations and of the analytical-empirical models for microstructure prediction in a wide range of process condition. The use of reliable instruments for simulation of casting process, with the adding of the implementation of experimental correlation microstructures-mechanical properties, allows for the evaluation of final properties and defects of castings, giving an important help in the optimization of the final product and its relative production process.