Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2014-11-10T11:11:38Z No. of bitstreams: 0 / Made available in DSpace on 2014-11-10T11:11:38Z (GMT). No. of bitstreams: 0 / O objetivo deste trabalho é verificar a validade e a acurácia dos resultados fornecidos pelos programas computacionais FRAPCON-3.4a e FRAPTRAN-1.4, utilizados no processo de simulação do comportamento de varetas combustíveis de reatores a água leve pressurizada PWR (Pressurized Water Reactor), sob situações operacionais de regimes permanente e transiente, em condições de alta queima (high burnup). Para realizar a verificação, foi utilizada a base de dados FUMEX-III, que fornece dados relativos a experimentos realizados com diversos tipos de combustíveis nucleares, submetidos a diversas condições operacionais. Através dos resultados obtidos nas simulações computacionais com os programas FRAPCON-3.4a e FRAPTRAN-1.4 e da sua comparação com os dados experimentais da base FUMEX-III, foi possível constatar que os programas empregados possuem um boa capacidade de predizer o comportamento operacional de varetas combustíveis de PWR em regime permanente a altas queimas e sob condição de transiente inicializado por reatividade (Reactivity Initiated Accident RIA). / Dissertação (Mestrado em Tecnologia Nuclear) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Este trabalho apresenta e consolida uma metodologia alternativa para a determinação de taxas de reação nuclear ao longo da direção radial das pastilhas combustíveis sem necessidade de intensos fluxos neutrônicos. Esta técnica se baseia na irradiação de um disco de UO2 inserido no interior de uma vareta combustível desmontável no núcleo do reator IPEN/MB-01. Após a irradiação são realizadas várias espectrometrias gama do disco utilizando um detector HPGe alternando sequencialmente 6 colimadores de chumbo com diâmetros diferentes. Consequentemente, as reações nucleares de captura radiativa que ocorrem nos átomos de 238U, juntamente com as fissões que ocorrem em ambos 235U e 238U são mensuradas em função de 6 regiões radiais distintas do disco combustível. As correções de eficiência geométrica devido à introdução dos colimadores no sistema de detecção HPGe são determinadas através do código MCNP-5. As medidas de taxa de fissão são realizadas utilizando o 99Mo como radionuclídeo traçador. Esse radionuclídeo foi estudado e provou-se ideal para estas medidas por possuir um comportamento linear de formação, alto rendimento de fissão e principalmente por emitir fótons de baixa energia. As medidas foram efetuadas irradiando discos de UO2 (com enriquecimento de 4,3%) na posição central do reator IPEN/MB-01 a potência de 100 Watts durante uma hora. Algumas medidas foram realizadas utilizando uma luva de cádmio envolta na vareta combustível para determinar as taxas de reação nuclear na faixa de energia epitérmica. Os resultados experimentais obtidos são comparados a cálculos de taxa de reação nuclear via MCNP-5 utilizando a biblioteca de dados ENDF/B-VII.0, os quais apresentaram discrepâncias de no máximo 9% para as taxas de captura no 238U e 14% para as taxas de fissão no U na faixa epitérmica. Foram obtidos valores máximos de 4,5% para incertezas relativas as taxas de captura total e epitérmica e para as taxas de fissão total e epitérmica valores máximos de 11,3%. / This research presents and consolidates an alternative methodology for determining nuclear reaction rates along the radial direction of the fuel pellets which does not require high neutron flux. This technique is based on irradiating a thin UO2 disk inserted into a removable fuel rod at the IPEN/MB-01 reactor core. Several gamma spectrometries are performed after irradiation using a HPGe detector. Six lead collimators with different diameters are sequentially alternated during this process, thus, the nuclear radioactive capture which occurs in 238U and the fissions which occur in both 235U and 238U are measured according to six different radial regions of the fuel disk. Geometric efficiency corrections due to the introduction of collimators in HPGe detection system are determined by MCNP-5 code. The fission rate measurements are performed using the 99Mo. This radionuclide was studied and proved ideal for these measurements because it is formed in linear behavior in the reactor core, have a high yield fission and emits low-energy photons. Measurements were performed irradiating UO2 disks (with 4.3% enrichment) in the central position of the IPEN/MB-01 core at 100 watts power level during one hour. Some measurements were performed using a cadmium glove wrapped in the fuel rod to determine the nuclear reaction rates in the epithermal energy range. The experimental results obtained are compared with nuclear reaction rate calculations by means of MCNP-5 with ENDF/B-VII.0 data library showing discrepancies of up to 9% in 238U capture rates and 14% for U fission rates for epithermal energies. Uncertainties regarding the nuclear capture rates have maximum values of 4.5% and the fission rates has maximum values of 11.3%.

La maladie de Crohn et la rectocolite hémorragique font partie des maladies inflammatoires chroniques de l'intestin (MICI). Le principal objectif des traitements anti-inflammatoires est de favoriser la délivrance du principe actif localement, spécifiquement sur les zones enflammées et de limiter les effets indésirables. Ainsi, plusieurs systèmes à libération colonique de molécules actives ont été développés. Parmi eux, les pellets présentent de nombreux avantages par rapport aux formes solides unitaires conventionnelles. Dans un premier temps, des pellets comptant une substance anti-inflammatoire naturelle et nutritive, la rutine, ont été développés. L'intérêt de cette molécule est de réduire considérablement les effets secondaires qui constituent un véritable problème dans les traitements actuels des MICI. Les pellets ont été enrobé avec les polysaccharides naturels se dégradant avec la flore colonique. Les études in vitro ont démontré une libération minimale du principe actif au niveau de l'estomac et du petit intestin. Par contre, une libération rapide et totale a été observée lors de l'exposition des pellets dans les conditions du milieu colonique. Les résultats des tests in vivo ont démontré que la rutine a atténué considérablement l'inflammation au niveau de colon et les pellets enrobés ont été aussi efficaces que les pellets d'acide 5-aminosalicylique (5-ASA) commercialisés. L'administration orale de rutine via les pellets enrobés et préparés avec le chitosan semble être une approche prometteuse, permettant la libération du principe actif au niveau des zones enflammées, pour le traitement des MICI tout en réduisant les effets secondaires. Le deuxième but de notre travail était d'élucider l'impact du chitosan, un polymère mucoadhésif, sur l'efficacité thérapeutique. Les pellets de 5-ASA ont été préparés à partir de cellulose microcristalline avec ou sans chitosan. Un enrobage constitué d'un polymère pH dépendant,1' Eudragit® FS, a ensuite été réalisé autour du noyau. Les tests de dissolution ont montré que le principe actif n'était pas libéré du pellet après 2 h en milieu acide. En revanche,la libération était rapide dans un milieu simulant l'environnement colonique. Les tests ex vivo avec les pellets contenant le chitosan ont montré des propriétés mucoadhésives importantes qui ont été confirmées par la concentration élevée du métabolite de 5-ASA dans les tissus coloniques des rats. De plus, nous avons a démontré que les pellets permettaient d'atténuer de façon significative l'inflammation du côlon. Ainsi, les pellets bioadhésifs enrobés possèdent des propriétés bénéfiques supplémentaires pour la libération du 5-ASA au niveau du côlon par rapport à des formes multidoses commercialisées pour le traitement des MICI. / Crohn's disease and ulcerative colitis are two related but distinct chronic inflammatory disorders of gastrointestinal tract (GIT), commonly denoted as inflammatory bowel disease(IBD). The main goal of the anti-inflammatory treatment of this disorder is to achieve maximal drug concentration in inflamed area and reduce systemic adverse effects. For this purpose several colon-spécifie drug delivery systems have been investigated. In addition, the design of pellets as oral drug delivery systems may provide many advantages over single unit preparations and thus improve patient compliance. It is well known that most existing treatments of IBD are associated with significant side effects and for this reason the formulation with a " food like " composition was designed. In the first part of our study, therapeutic efficiency of rutin/chitosan pellets with coatings based on natural polysaccharides degraded by colonie microbiota compared to commercialized 5-aminosalicylic acid (5-ASA) pellets was investigated. Release profiles ofcoated pellets showed a minimal drug release in simulated stomach and small intestine following by rapid drug release upon exposure to the colonie fluid. The results from in vivo testing showed that rutin attenuated efficiently inflammation in the colon and coated pellets were as effective as 5-ASA pellets in mitigating experimental colitis. The studies demonstrated that rutin administration via chitosan core coated pellets seems to be apromising approach for colon-specific delivery since they could interact easily with the mucin layer and deliver drug especially to the inflamed colonie area to relieve symptoms of IBD omitting side effects related to conventional treatment. The second objective of this thesis was to explore the impact of additional mucoadhesive polymer chitosan in the pellets core on the therapeutic efficiency. For this purpose, 5-ASA loaded pellets were produced by extrusion/spheronisation method and subsequently coated with pH-sensitive polymer Eudragit® FS. No drug release at pH 1.2within 2 h, and release as intended in the simulated distal ileum and colon was observed. Chitosan-core pellets showed efficient mucoadhesive properties in ex vivo bioadhesion testing which were also confirmed by increased concentration of 5-ASA metabolite in the colonie tissues in rats. The pellets were tested in preexisting colitis and the results revealed significant attenuation of the colonie inflammation. We can conclude, that bioadhesive chitosan-corepellets showed additional beneficial properties for colonie 5-ASA delivery in the treatment of IBD over marketed dosage formulation.

Luossavaara-Kiirunavaara AB (LKAB) rullar järnmalmslig till råkulor, som sedan bränns till pellets. Råkulorna bildas i rullkretsar som består av rulltrummor och rullsiktar. Under 2017 färdigställdes en pilotskaleanläggning för kulrullning i LKAB:s Agglomeringslaboratorium i Malmberget. Syftet med anläggningen är att prediktera dynamiken i en storskalig rullkrets, under olika betingelser. Detta examensarbete är ett första försök att i forskningssyfte studera gensvaret i LKAB:s pilotrullkrets. Syftet var att undersöka om pilotrullkretsen kan prediktera dynamiken och råkulekvalitet i rullning i storskaliga rullkretsar och målet var att fastställa ett effektivt körsätt. Kulrullning är inom LKAB:s kärnkompetens och därför har reagensursprung och karaktär samt dimensionering av rullkretsen lagts med sekretess. Kodnamn används både för sliger och reagens. Arbetet inleddes med att skapa ett körschema med målet att så många olika blandningar som möjligt kunde köras i pilotrullkretsen under en normal arbetsdag. Fem olika blandningar kunde köras. Fyra olika tillsatser testades: bentonit, ett flotationsreagens (FLOT), ett organiskt bindemedel (OB) och en ny utvecklingsprodukt (UTV). Första körningen i pilotrullkretsen var med varierande doseringar av bentonit eftersom dess inverkan i kulrullning är välkänt hos LKAB. Försök två och tre, med FLOT respektive OB, kunde jämföras mot tidigare erfarenhet från storskaliga försök. Det fjärde och sista försöket var ett test hur pilotrullkretsen predikterade utvecklingsprodukten UTV. Varje typ av försök utfördes två gånger. Pilotrullkretsen predikterade väl både dynamik och råkulekvalitet i alla de tre försöken där erfarenhet från storskaliga körningar var tillgängligt. Den nya, okända, UTV-produkten visade en förbättrad råkulekvalitet, utan att dynamiken i kretsen påverkades negativt. UTV kan därför vara ett intressant alternativ för ett framtida storskaligt försök hos LKAB. Det framtagna körschemat fungerade mycket väl. Ett ”grundanalyspaket” har skapats för att underlätta planering och genomförande för framtida pilotrullkretsförsök hos LKAB. Antalet personer som behövs vid rullkretskörningar beror på antalet blandningar och analyser. Vid enklare körningar behövs minst fem personer, utöver försöksledaren. Mer komplexa körningar kan kräva sju personer. / Luossavaara-Kiirunavaara AB (LKAB) produce pellets from magnetite iron ore. Pellets are formed by balling moist iron ore concentrate to green pellets, which are then burned to pellets. The green pellets are formed in balling circuits consisting of balling drums and roller decks for screening. In 2017 a pilot scale balling circuit with a drum was completed in LKAB's agglomeration laboratory in Malmberget. The purpose of the pilot balling circuit is to predict the dynamics in a full scale balling circuit under different conditions. This master degree project is an initial attempt to study the response in LKAB's pilot circuit in terms of green pellet quality and dynamics in the circuit. The goal was to determine an effective way to run experiments and to investigate whether the pilot circuit can predict the dynamics of balling in large-scale circuits. Pelletizing production is within LKAB's core competence, and therefore the origin and character of the reagents, as well as the design of the pilot balling drum circuit, are confidential. Code names are used for both iron ore concentrates and reagents. The work began by creating a test procedure with the aim of running as many different mixtures as possible in the pilot balling circuit during a normal working day. Five different mixtures could be run. Four different additives were tested: bentonite, a flotation reagent (FLOT), an organic binder (OB) and a new development product (UTV). The first experiment in the pilot balling circuit was run with varying doses of bentonite because its impact in balling is well known at LKAB. Experiment two and three, with FLOT and OB, could be compared to previous experience from large scale test runs. The fourth and last experiment was a test of how the pilot circuit predicted the behavior of a new development product UTV. Each type of experiment was performed twice. The pilot balling circle predicted well both dynamics and green pellet quality in all three experiments where experience from large-scale runs was available. The new, unknown, UTV product showed improved green pellet quality, without affecting adversely on the dynamics of the circuit. UTV can therefore be an interesting option for a future large scale run at LKAB. The developed working schedule worked very well. A "basic analysis package" has been created to facilitate planning of future experiments in the pilot balling circuit. The number of persons needed to run the circuit depends on the number of mixtures and analyzes. For smaller experiments, at least five people is required, in addition to the leader of the experiments. More advanced experiments will demand seven people.

Dans la dernière décennie, les autorités de santé ont promulgué une réglementation pédiatrique orientée sur le développement et la disponibilité des formulations adaptées à l'âge, la taille, l'état physiologique et les besoins de la population pédiatrique. Généralement, l'administration de médicaments par la voie orale est toujours préférée aux autres voies d'administration car elle est pratique, économique et bien acceptée. Au cours des dernières années, de nouvelles formulations solides ont été développés comme par exemple les comprimés orodispersibles car ils sont faciles à administrer, ne nécessitent pas d'eau et, dès lors que la dispersion est rapide, la biodisponibilité du médicament peut être significativement supérieure à celle observée avec les comprimés classiques offrant ainsi des solutions alternatives pour les enfants. D’autre part, les mini-granules présentent de nombreux avantages par rapport aux formes galéniques solides unitaires car ils se dispersent à travers le tractus gastro-intestinal, réduisant ainsi l'irritation locale du principe actif, et permettent l'amélioration de l'absorption du médicament ainsi que la diminution des fluctuations de concentration plasmatique. De plus, avec ces formes multiparticulaires, il est possible de contrôler la vitesse de libération du médicament, ce qui réduit les effets indésirables. Quelques études ont porté sur la compression des mini-granules non enrobés, ce qui pourraient limiter les problèmes pendant la compression comparativement aux mini-granules enrobés pour lesquels l’enrobage pourrait être détruit.L'objectif global de ce travail était de développer un comprimé multiparticulaire orodispersible (MUP-ODT) qui permet la libération contrôlée d'acétaminophène (APAP), utilisé comme principe actif modèle, contenue dans les mini-granules des comprimés orodispersibles.La première partie a déterminé les propriétés mécaniques des mini-granules d’APAP obtenus par la technique d’extrusion-sphéronisation en contenant différents types d'excipients et différents pourcentages de principe actif pour produire un système matriciel à libération contrôlée.La seconde partie de cette étude a examiné la faisabilité de comprimer des mini-granules non enrobés à base de cellulose microcristalline (MCC) dans différentes formulations orodispersibles et d’étudier l'influence du pourcentage de mini-granules, le type de désagrégant et la force de compression.La troisième partie a été dédiée à la production des MUP-ODTs qui permettent la libération contrôlée d’APAP en utilisant différents pourcentages d’Eudragit® pour créer un système matriciel sans changement significatif dans le profil de libération après la compression.Enfin, dans la dernière partie, un plan d'expérience a été effectué pour déterminer les paramètres optimaux pour produire les MUP-ODTs. L'évaluation du masquage de goût a été réalisée par la langue électronique et la méthode de dissolution à l'aide d'une pompe à seringues qui utilise de fiables volumes de milieu afin de simuler le comportement dans la bouche d’un enfant. Plusieurs polymères ont été utilisés avec succès pour produire des mini-granules d’APAP de type matriciel avec différents pourcentages de principe actif. Les MUP-ODTs ont été obtenus en montrant la faisabilité de leur production et l’obtention de bonnes propriétés mécaniques. Ils permettent la désagrégation très rapide et la possibilité de libération modifiée, tout en offrant une déglutition facile pour un enfant et une flexibilité de posologie. / In the last decade, medical agencies have promoted a pediatric regulatory focusing on the development and availability of age-appropriate formulations suitable for age, size, physiological condition and treatment requirements for the pediatric population. In general, oral drug delivery is still preferred over the other drug delivery routes since it is convenient, economical and user friendly. In recent years, a number of new solid oral drug delivery platforms such as orodispersible tablets have been developed as they are easy to administer, do not require additional water and, as long as dispersion is rapid, the bioavailability of the drug can be significantly greater than those observed in conventional tablet dosage forms offering a potential alternative for pediatric patients. In parallel, multiparticulate products present many advantages compared to single-unit dosage forms as they distribute fast through the gastrointestinal tract, thus reducing local irritation caused by the active ingredient, enhancing drug absorption and decreasing fluctuation of plasma peaks. Moreover, it is possible to control the drug release rate, resulting in fewer adverse effects. Only few studies have dealt with the compaction of uncoated pellets, which potentially could provide fewer problems during compaction than coated pellets, in particular by reducing damages on the coating.The overall objective of this study was to develop a Multiple-Unit Pellet Orodispersible Tablet (MUP-ODT) allowing for the controlled release of acetaminophen (APAP), used as a model drug, which is contained in the pellets of the orodispersible tablets.The first part determined the mechanical properties of APAP pellets produced by the extrusion-spheronization technique containing different types of excipients and different drug load percentages to produce a controlled release matrix system.The second part of this study examined the feasibility to compress uncoated free drug MCC pellets with different orodispersible formulations to assess the influence of the percentage of pellets, type of disintegrants and compression force.The third part was dedicated to produce MUP-ODTs which allowing for controlled-release of APAP using different percentages of Eudragit® to create the matrix system without significant changes in the release profile after compression.Finally, a design of experiments was carried out to determinate the optimal parameters to produce MUP-ODTs.Taste-masking evaluation was realized using the electronic tongue. Dissolution test was performed using a syringe pump and small volumes of aqueous medium at low flow rates to mimic the behavior in the mouth of the child.Different polymers were successfully used to produce APAP matrix pellets with different drug loadings. MUP-ODTs were successfully obtained demonstrating their feasible production with good mechanical properties. They enable very fast disintegration and modified release properties, but also offer easy swallowing for children and dose flexibility.

Please read the abstract in the section 00front of this document / Dissertation (M Eng (Metallurgical Engineering))--University of Pretoria, 2006. / Materials Science and Metallurgical Engineering / unrestricted

The diploma thesis focuses on creating the business plan that will used for formation firm, that produces pellets used as fuel. There are theoretical and practical part, which is an analysis of market as terms of customers and suppliers, so terms of competition and there is also a financial plan.

The thesis is a technical solution for heating two apartment buildings. The project is designed in two versions. The first variant is source of heat boilers for pellets, in the second variant, the heat source heat pumps type of land / water. Part of this work is an experiment which deals with the measurement of floor heating.

Public and private incentive programs have encouraged conversions to high efficiency, low emissions wood heating systems as a strategy to promote renewable energy and support local economies in the Northeastern US. Despite these efforts, the adoption of these systems remains slow. The study that is the subject of this dissertation examines several social, economic, policy and environmental factors that affect the decisions of individuals and small-scale institutions (local business and community facilities) to transition to automated wood pellet boilers and furnaces (AWPH) utilizing local fuel sources. Due to the complexity and risk associated with conversion, the transition to these systems can help further both a practical and theoretical understanding of the global transition to non-fossil fuel technologies. Chapter One of this dissertation examines this notion in more detail, as well as spells out the research questions of this study. Chapter Two delves into the research methods and their implications for other studies of energy transitions. These methods include interviews with 60 consumers, technology and fuel suppliers, and NGO and state agency personnel. These provided in-depth qualitative data which are complemented by a four-state survey (New Hampshire, Vermont, New York, and Maine) of adopters and informed non-adopters of AWPH systems (n=690; 38% response rate). Interview and survey questions, as well as subsequent coding, was developed through use of diffusion of innovation theory, the multi-level perspective on sociotechnical transitions, as well as through collaboration with industry experts and research partners. Chapters Three and Four offer a discussion of the results and their implications. Specifically, Chapter Three examines the complex system actors, elements, and interactions that are part of the transition from fossil fuel technology to AWPH. Chapter Four focuses on the data surrounding state and private programs that encourage the use of AWPH and the implications that this data has for effective climate mitigation and energy policy. Data show that AWPH consumers, who should be considered “early adopters” due to the small number of AWPH adopters in the region, are largely value-driven but are also concerned about upfront costs and lack of available technical support and fuel delivery options. Both environmental values (e.g. desire to find alternative to fossil fuels, concern for air quality and belief in climate change) and social values (e.g. support for the local economy and wood products industry) influenced consumer decisions, especially when fuel oil prices were low. Financial incentives, which are offered by all four states in the study region, were highly influential, but additional decision support offered by a non-profit (e.g. site visits, informational workshops, local print media) were rated highly by consumers where they were available. These additional supports, as well as the community-based nature of the non-profit program, enabled a broader range of people (lower income, more risk averse) to choose AWPH as well as created more efficiency in the supply chain. This approach created a reinforcing feedback loop between broader early adopters of AWPH, normalization of AWPH technology and its associated infrastructure, and increased levels of technical support and fuel availability. These findings suggest that efforts to increase adoption of renewable technologies that use locally harvest fuels take a community-based and system-wide approach, targeting both consumer and supplier motivations and barriers.

Um bei der Herstellung der Holzpellets den Energieaufwand zu minimieren und gleichzeitig die Qualitätsanforderungen der DINplus zu erfüllen, werden häufig Presshilfsmittel beim Pelletieren eingesetzt, bisher vor allem Mais- und Weizenstärke. Um flexibler auf veränderte Markt- und Rohstoffbedingungen reagieren zu können, besteht von Seiten der Hersteller Bedarf an alternativen Presshilfsmitteln. Allerdings ist deren Einfluss auf das Verbrennungs-, Emissions- und Ascheerweichungsverhalten nur unzureichend erforscht. Im Rahmen eines Forschungsprojektes zur Optimierung der Pelletproduktion wurden in dieser Diplomarbeit Versuche durchgeführt, um den Einfluss verschiedener natürlicher Presshilfsmittel, der Pelletqualität (Feinanteil, Stückigkeit) und der Feuerungsart (Unterschub- und Abwurffeuerung mit Brennerschale) auf das Emissionsverhalten (Kohlenmonoxid-, Stickoxid-, Gesamtkohlenstoff und Staubgehalt im Abgas), den Anlagenbetrieb (Brennstoffförderraten, Abgasverluste, Luftüberschuss) und das Ascheerweichungsverhalten beim Betrieb von zwei Kleinfeuerungsanlagen mit DINplus-konformen Holzpellets, zu untersuchen.