No abstract available

Thesis (Ph.D) -- McMaster University, 1997. / Includes bibliographical references. Also available via World Wide Web.

Thesis (Ph.D.)--University of Melbourne, Dept. of Mathematics and Statistics, 2007. / Typescript. Includes bibliographical references (leaves 143-151).

Tez (Yüksek Lisans) - Süleyman Demirel Üniversitesi, Fen Bilimleri Enstitüsü, Maden Mühendisliği Anabilim Dalı, 2008. / Bibliyografya var.

Thesis (Ph.D.)--Chemical Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Hsieh, Jeffery; Committee Member: Breedveld, Victor; Committee Member: Empie, Jeff; Committee Member: Forney, Larry; Committee Member: Singh, Preet

Techn. Universiẗat, Diss., 2002--Darmstadt.

Resumo: O presente estudo foi realizado para investigar a prevalência de enteroparasitas em crianças e funcionários da creche do município de Pratânia, Estado de São Paulo, e caracterizar geneticamente os isolados de Giardia duodenalis obtidos dos indivíduos desse grupo empregando gdh e tpi como genes-alvo. Para isso, amostras de fezes de 141 crianças com idade de zero a seis anos e de 18 colaboradores foram colhidas e processadas pelo método de centrífugo-flutuação e pelo kit TF-test®. Nas 141 crianças, parasitas e/ou comensais intestinais foram diagnosticados em 64 (45,4%), das amostras, sendo Giardia (22%) e Cryptosporidium (22%) os parasitas mais freqüentes. Nos funcionários, Giardia foi diagnosticada em apenas uma amostra (5,5%) e o protozoário comensal Entamoeba coli (22,2%) foi o mais prevalente. Empregando técnicas baseadas em PCR, o DNA extraído de 86 (31 amostras positivas e 55 negativas para Giardia no exame microscópico) foi amplificado e os produtos obtidos foram seqüenciados. A análise de 35 seqüências revelou a ocorrência de infecção pelos genótipos A (28,6%) e B (71,4%), subtipos AI, AII, BIII/BSI e BIV, no entanto, associações entre os genótipos e fatores de risco para a infecção não foram observadas. O alinhamento das seqüências de gdh e tpi, revelou a presença de um a 12 SNPs (Single Nucleotide Polymorphisms) em isolados dos genótipos A e B, sendo que em alguns deles, as mutações foram responsáveis por alterações nas seqüências de aminoácidos. A infecção de seis crianças de um mesmo grupo e de uma funcionária por isolados classificados como genótipo B e apresentando seqüências nucleotídicas 100% idênticas entre si sugere a ocorrência de transmissão antroponótica na população estudada. Além disso, a maior prevalência do genótipo B, grupo predominante nas infecções humanas, reforça o fato de que a transmissão... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The present study was conducted to investigate the prevalence of intestinal parasites in children and employees of a daycare center of Pratania, São Paulo State, and to evaluate the genotypes Giardia duodenalis isolates obtained from individuals in this group by using gdh and tpi genes as targets. Fecal samples of 141 children aged zero to six years and 18 employees were processed by a flotation method and the TF-Test® kit. Of the 141 children samples, parasites and/or commensal organisms were diagnosed in 64 (45.4%) samples, and Giardia (22%) and Cryptosporidium (22%) were the most frequent parasites. In employees, Giardia was diagnosed in only one sample (5.5%) and the commensal protozoan Entamoeba coli (22.2%) was the most prevalent. DNA extracted from 86 samples (31 samples positive and 55 negative for Giardia by microscopic examination) was amplified by PCR and the products were sequenced. The analysis of 35 sequences revealed the occurrence of infection with genotypes A (28.6%) and B (71.4%) subtypes AI, AII, BIII / BIV and BSI, however, associations between genotypes and risk factors for infection were not observed. The alignment of the sequences revealed SNPs (Single Nucleotide Polymorphisms) in both genotypes A and B, altering the amino acid sequence of some isolates. Among isolates identified as genotype B, six obtained from children of the same group and one from the only one employee infected with Giardia showed gdh and tpi sequences different from reference ones, but 100% identical to each other. This data is suggestive of anthroponotic transmission in the studied population. In addition this finding, the higher prevalence of genotype B, the main group associated to human infections, reinforces the fact that anthroponotic transmission has importance in collective environments that meet children at an age that they still have not practice the basic precepts of hygiene. / Orientador: Semíramis Guimarães Ferraz Viana / Coorientador: Teresa Cristina G. de Oliveira-Sequeira / Banca: Paulo Eduardo Martins Ribolla / Banca: Marcelo Urbano Ferreira / Mestre

A amostra utilizada para este estudo faz parte do material depositado na barragem de rejeitos da mina de carvão da “Carbonífera Criciúma”, localizada na região sul do país (Santa Catarina). Usualmente os finos de carvão junto com a parte mineral, provenientes do processo de beneficiamento são denominados de “lodo” e são descartados como rejeitos, depositados na bacia de decantação. A recuperação dos finos de carvão provenientes do lodo pode propiciar a obtenção de um concentrado que poderia ser aproveitado como combustível na geração de energia elétrica. Também pode contribuir como fator de diminuição do impacto ambiental, minimizando a formação da drenagem ácida de minas (DAM), gerada pelo conteúdo de enxofre contido no material em estudo, além de reduzir o espaço físico ocupado pela barragem de rejeito. Entre os métodos de beneficiamento de carvão, a flotação se destaca como um dos mais importantes para concentração desse lodo, em particular no tratamento de partículas finas. Para caracterizar o lodo, fez-se um estudo de análise granulométrica, que permite definir que estamos trabalhando com um material fino uma vez que 83,0% é menor que 0,710 mm. Concomitantemente realizaram-se análises elementares e análises imediatas, seguindo as normas Brasileiras. NBR 8293, NBR 8289, NBR 8290, NBR 8299. Os resultados mostraram que, a partir da alimentação com cerca de 63% de cinzas, foi possível obter concentrados com teores de cinzas de aproximadamente de 30%, com recuperações mássicas de cerca de 40%, demonstrando que é possível a recuperação da matéria orgânica, a partir do lodo por flotação convencional. / The sample used for this study is part of the material deposited in the tailings dam of the coal mine "Carbonífera Criciúma" located in the southern region (Santa Catarina). Usually the coal fines along with the mineral part, from the beneficiation process are called "sludge" and are discarded as waste, and deposited in the tailings pond. The recovery of coal fines can facilitate the obtainment of a concentrate that could be used as fuel in power generation. It can also contribute as a factor of environmental impact reduction by minimizing the formation of acid mine drainage (AMD), generated by the sulfur contained in the material under study, in addition to reducing the physical space occupied by the tailings dam. Among the methods coal beneficiation, flotation stands out as one of the most important concentration of the ore, particularly in the treatment of fine particles To characterize the material, we need to do a particle size analysis’s study, it will allows us to define that we are dealing with a 83,0% thin material, thinner than 0,710 mm. Simultaneously we will do elemental analyzes and spot analysis, following the Brazilian standard. NBR 8293, NBR 8289, NBR 8290, NBR 8299. The results showed that, from a supply with about 63% ash concentration, were obtained around 30% of ash and about 40% of carbonaceous mass recoveries. This demonstrate that it is possible to recover organic matter from the tailing by conventional flotation.

La flottation est la principale étape du processus de recyclage,ayant pour but l’élimination de l’encrede la pâte. Pour une moyenne de seulement 2% d’encre présent dans la pâte, le rendement estd’environ 80 %. Les pertes sont ainsi principalement composées de fibres, charges minérales etéléments fins. Le procédé de flottation est le seul processus permettant une séparation sélective desparticules d’encre de la pâte à papier, lors du recyclage des papiers récupérés. Ce processus estappliqué par toutes les usines européennes de désencrage et, bien qu'il soit reconnu comme étant leplus sélectif, il génère des pertes solides qui restent encore trop important (15 à 20% de pertes) parrapport au 2% en poids de l'encre appliquée en général sur imprimé. Ainsi, la sélectivité de la flottationa besoin d'être améliorée. Cette amélioration permettrait à la fois d'augmenter le rendement duprocédé de désencrage ainsi que de réduire les volumes de boues produites au cours de désencrageet donc de simplifier tous les problèmes liés à la valorisation de ces boues. Les travaux retranscritsdans ce mémoire ont, dans un premier temps, pour but d'améliorer la connaissance fondamentale desphénomènes se produisant au cours de flottation, en particulier pour obtenir une meilleureconnaissance i) sur les mécanismes de transport des différentes particules (encres, fibres decellulose, éléments fins et charges minérales) au cours de la flottation, en présence de différentstensio-actifs utilisés, ii) des rôles des la chimie utilisée ainsi que leur propre utilisation lors de laflottaison. Dans un deuxième temps, la modélisation des mécanismes de transport dans la pâte etdans la mousse, en tenant compte de paramètres mécaniques (débit de pâte, d’air, turbulence, laconception des cellules…) et physico – chimiques, pour ainsi finalement développer une simulation duprocédé de flottation permettant d'évaluer l'incidence de la chimie utilisée ainsi que des paramètresmécaniques des cellules. Cette simulation permettra par la suite d’améliorer à la fois l’efficacité descellules existantes mais aussi des lignes de désencrages. / Flotation is the main step of de-inking to remove the ink from the pulp. Whereas the target is toremove 2% of ink from the pulp, there is a loss of 20% of total matters (fibers, fillers and ashes). Theflotation process is the only process allowing to more or less selectively separate the particles frominks during recycling of recovered papers. This process is applied by all the European deinking millsand, although being recognized as being the most selective, it generates solid losses which remainstill too important (15 to 20% of losses) compared to the 2% of ink in weight applied to printed papers.Thus, the selectivity of flotation requires to be improved. Such improvement would at the same timeallow to increase the deinking process yield but also to reduce in parallel the volumes of sludgegenerated during de-inking and thus to simplify all the problems connected with the valorisation ofthese sludges. On the one hand, the objectives of this study are to improve fundamental knowledge ofthe phenomena occurring during flotation, in particular to obtain a better knowledge i) on mechanismsof transport of the various particles (ink, fibres and fines cellulose, mineral loads) during flotation in thepresence of various surface-active components from de-inking, ii) of the role of surface-activesubstances and their elimination during flotation. On the other hand, modelling of the mechanisms oftransport in the pulp and in the froth, taking into account mechanical parameters (air ratio, turbulence,design of the cells) and physico – chemical parameters has been highlighted to finally develop asimulation of the flotation process allowing to evaluate the incidence of the design of the cells,simulation which should then make it possible to improve the effectiveness of the existing cells.

Après un accident nucléaire tel que Fukushima en 2011, le césium 137 radioactif est transporté de l’atmosphère vers le sol par l’eau de pluie. Les argiles sont des espèces minérales finement divisées (1-100 µm) naturellement présentes dans les sols qui sont connues pour leurs propriétés adsorbantes sélectives et irréversibles vis-à-vis des ions Cs. L’objectif de la thèse est d’explorer la faisabilité d’un procédé, appelé flottation, pour l’extraction sélective des fines particules d’argile contaminée afin de réduire le volume de terres à stocker. La flottation consiste à séparer les espèces en fonction de leurs propriétés de surface. Les particules les plus hydrophobes sont collectées par les bulles d’air et transportées dans la mousse tandis que les particules hydrophiles restent en suspension. Des tensioactifs cationiques sont employés pour s’adsorber de façon sélective à la surface des argiles et augmenter leur degré d’hydrophobie. L’argile illite et le tensioactif TTAB de type bromure d’ammonium ont été sélectionnés pour l’étude. Les propriétés des suspensions d’illite/TTAB ont été déterminées (granulométrie, potentiel zêta…). Les mousses ont ensuite été étudiées à l’échelle laboratoire. Nous avons montré que les particules d’argile avaient bien un effet stabilisant sur la mousse. Par ailleurs, une sélectivité pour les fines particules (3 µm) est observée dans les mousses. La 2nde partie du travail a consisté à contribuer au développement d’une colonne de flottation fonctionnant en continu et à réaliser des essais sur le système illite/TTAB. L’influence des paramètres de concentration et de granulométrie de l’argile, de concentration en TTAB et de débit d’air sur les rendements d’extraction et les propriétés drainantes de la mousse a été étudiée. Grâce à cette étude, deux paramètres de transport ont été dissociés et extraits : la constante de flottation vraie et le coefficient de drainage qui sont ensuite employés pour une étude de dimensionnement de colonne de flottation industrielle. / After a nuclear accident like Fukushima, the radioactive cesium 137 is transported from the atmosphere to the soil by rain water. Clays are mineral species which are naturally present in soils. These micrometric minerals (1- 100 µm) are very efficient and selective adsorbents for Cs ions. The objective of this PhD thesis is to look at the feasibility of a process called flotation to selectively extract these contaminated clay particles and to reduce the volume of soil to store. Flotation consists in separating minerals according to their surface properties. The most hydrophobic particles are collected by air bubbles and are transported up to the froth whereas the hydrophilic particles remain in the suspension. Cationic surfactants are employed to selectively adsorb on clays surface and increase its hydrophobicity. It was chosen to focus on systems containing illite clay and an ammonium bromide cationic surfactant called TTAB. The properties of illite and TTAB suspensions were determined (particle size, zeta potential, adsorption isotherm of TTAB, turbidity, rheology). Then, foaming ability, stability and drainage properties of these suspensions were looked at by using a lab scale instrumented column. It was shown that clay particles have a stabilizing effect on the froth. Moreover, selectivity for the smallest clay particle size fraction (3 µm) in foams was observed. The 2nd part of the work consisted in performing flotation experiments on illite clay and TTAB suspension with a new “mini” pilot flotation column in continuous mode. The influence of TTAB concentration, air flow and illite clay concentration and granulometry on foam drainage properties and extraction yields was determined. From this study, two transport parameters were dissociated and extracted: the true flotation rate constant and the drainage coefficient. Finally, they were used to perform a scale-up study of an industrial flotation unit.