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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1451

Interação entre células-tronco de polpa dentária imatura e o osteossarcoma canino / Interaction between immature dental pulp stem cells and canine osteosarcoma

Dayane Alcântara 31 October 2014 (has links)
O osteossarcoma é um tumor ósseo maligno, de maior ocorrência em cães, possui rápido crescimento e alto potencial metastático. Assim, o cão é um modelo útil para o estudo da doença em humanos, tendo em vista as semelhanças clínicas e histopatológicas que ocorrem em ambas às espécies. Atualmente, os estudos a respeito de células-tronco são promissores considerando seu alto potencial terapêutico. Entretanto, ainda prevalecem muitas dúvidas referentes ao tratamento de tumores utilizando a terapia celular. Este tema é pouco conhecido e estudado, por isso, o objetivo deste trabalho foi avaliar a interação entre células-tronco obtidas da polpa dentária canina com as células derivadas osteossarcoma canino. Foram realizados cocultivos celulares das células derivadas de polpa dentária canina, osteossarcoma canino e derivadas de osso normal canino. Analisou-se os aspectos morfológicos das células cocultivadas e controle, assim como a atividade proliferativa, a morte celular, o potencial elétrico mitocondrial e a expressão gênica. A partir dos resultados obtidos, concluiu-se que a interação entre a célula-tronco da polpa dentária canina imatura e as células de osteosarcoma canino não apresentam alterações morfológicas. Entretanto, as células-tronco derivadas da polpa dentária canina e de osso fetal canino sadio parecem servir de suporte para o crescimento tumoral. Além disso, a cocultura celular, em todos os grupos testados, promove alterações na expressão gênica e proteica. / Osteosarcoma is a malignant bone tumor most frequent in dogs. It has fast growth and high metastatic potential. Thus, the dog is an useful model for the study of human disease, due to the clinical and histological similarities found in both species. Currently, studies about stem cells are promising considering its high therapeutic potential. However, many doubts still exist regarding the treatment of tumors using cell therapy. This theme is little known and studied. Therefore, the aim of this study was to evaluate the interaction between stem cells obtained from canine immature dental pulpstem cells with osteosarcoma cells derived from dogs. Cellular coculture were performed using cells derived from canine dental pulp, canine osteosarcoma and canine normal bone. The morphological aspects of cocultured cells and control were analyzed, as well as proliferative activity, cell death, the mitochondrial membrane electric potential and gene expression. In summary, it was concluded that the interaction between stem cells from canine immature dental pulp and canine osteosarcoma cells did not show morphological changes. However, stem cells derived from canine dental pulp and healthy canine fetal bone serve to support tumor growth. Furthermore, the cell coculture in all groups tested, causes changes in gene and protein expression.
1452

Estudo longitudinal de lesões profundas de cárie após a remoção incompleta da dentina cariada: 36-45 meses de acompanhamento / Study of deep caries lesions after incomplete dentine caries removal: 36-45 months follow-up study

Oliveira, Elenara Ferreira de 16 October 2006 (has links)
Made available in DSpace on 2014-08-20T14:30:11Z (GMT). No. of bitstreams: 1 Tese _ Elenara_Ferreira_ Oliveira.pdf: 694369 bytes, checksum: 410d5111d12d3fad68258a97ba292b1b (MD5) Previous issue date: 2006-10-16 / This paper assesses clinical/radiographic changes after incomplete carious dentine removal and tooth sealing. 32 teeth with deep caries lesions were studied. The treatment consisted of incomplete excavation, application of Ca (OH)2 layer, sealing for a 6-7 month period, and then restored. Standardized bitewing radiographs were taken after the temporary sealing, and at 6-7, 14-18, and 36-45 month intervals. The digitized images were analyzed: qualitatively in regard to the radiolucent zone (RZ) depth and tertiary dentine (6-7 and 36-45 months) and quantitatively in regard toradiographic density by image subtraction (6-7, 14-18, and 36-45 months). The subtractions were performed in the RZ beneath the restoration and in two control areas (CA). During the 6-7 month period, there was 1 pulp necroses and 1 pulpexposure, and at the 36-45 month interval, 3 fractures and 3 withdrawals. Nine cases showed a decrease in RZ depth in the 6-7 month period and 3 more cases, at the 36- 45 month period. Four cases displayed tertiary dentine. The radiographic density means and standard deviations were: 129.42±5.83, 127.65±4.67, and 126.86±7.03 (CA, P>0.05) and 132.96 ±7.41, 132.90±5.99, and 132.62±8.68 (RZ, P>0.05) for the 1st, 2nd, and 3rd periods. The radiographic density of the CA differed from the RZ (Tukey test, p<0.05). Interference in microbiological metabolism by partial dentine removal and by tooth sealing arrest lesion progression, suggesting that complete dentine caries removal is not essential to controlling caries progression. / Este trabalho avaliou alterações clínicas/radiográficas após a remoção incompleta da dentina cariada e selamento do dente. Trinta e dois dentes com lesões profundas de cárie foram estudados. O tratamento consistiu da escavação incompleta da dentina cariada, aplicação de uma camada de cimento de Ca(OH)2, selamento provisório por um período de 6-7 meses, e restauração. Radiografias interproximais foram feitas logo após o selamento temporário e em intervalos de 6-7, 14-18, e 36-45 meses. As imagens digitalizadas foram analisadas: qualitativamente em relação à profundidade da zona radiolúcida (ZR) e deposição de dentina terciária (6-7 e 36-45 meses) e quantitativamente, em relação à densidade radiográfica, através da subtração de imagem (6-7, 14-18, e 36-45 meses). As subtrações foram realizadas na ZR, abaixo da restauração, e em duas áreas controles (AC). Durante período de 6-7 meses houve uma necrose e uma exposição pulpar, e no intervalo de 36-45 meses, três fraturas e três perdas de pacientes. Nove casos mostraram uma diminuição da profundidade da ZR no período de 6-7 meses e mais três casos no intervalo de 36-45 meses. Em quatro casos foi observada a deposição de dentina terciária. As médias de densidade radiográfica e desvio-padrão foram: 129.42±5.83, 127.65±4.67, e 126.86±7.03 (AC, p>0.05) e 132.96±7.41, 132.90±5.99, e 132.62±8.68 (ZR, p>0.05) para o 1º, 2º e 3º períodos, respectivamente. A densidade radiográfica das AC foi diferente da ZR (teste de Tukey, p<0.05). A interferência no metabolismo microbiano promovida pela remoção parcial da dentina cariada e selamento do dente provocou a paralisação da lesão, sugerindo que a remoção completa da dentina cariada não é essencial para o controle da progressão da cárie.
1453

[en] USE OF ADVANCED OXIDATION PROCESSES FOR PULP MILL WASTEWATER TREATMENT / [pt] USO DE PROCESSOS OXIDATIVOS AVANÇADOS PARA O TRATAMENTO DE EFLUENTE DE INDÚSTRIA DE CELULOSE

MANOELA DEMORI LACOMBE PENNA DA ROCHA 25 January 2018 (has links)
[pt] O presente trabalho avalia a utilização de dois diferentes tipos de POA, Fenton-Zero - processo Fenton utilizando ferro zero valente: Fe0/H2O2 - e UV/H2O2 para o tratamento de efluente de indústria de celulose tratado biologicamente. Os parâmetros observados foram DBO, DQO, COT, cor e ABS280nm (medida de compostos ligninícos). Os experimentos foram conduzidos em batelada, em escala de laboratório e utilizando efluente real de indústria de celulose tratado biologicamente. Para os testes com o processo Fenton Zero foram realizados experimentos de acordo com um planejamento fatorial 2 elevado a 3, investigando a influência das variáveis pH, dosagem de peróxido de hidrogênio e massa de ferro zero valente fornecida por volume de solução. Como fonte de ferro foi utilizada lã de aço comercial nas concentrações de 5,5 g/L, 6,5 g/L e 7,5 g/L. As concentrações iniciais de peróxido de hidrogênio estudadas foram de 456,9 mg/L, 913,7 mg/L e 1370,6 mg/L e os valores de pH variaram entre 5.5, 6.5 e 7.5. Foram obtidas médias de remoção de 57,1 por cento de DQO, 67,2 por cento de DBO, 90,5 por cento de Cor, 83,4 por cento de compostos lignínicos e 54 por cento de COT, além de 9,52 mg/L de DBO final e 60,1 mg/L de DQO final. Já os testes com o sistema UV/H2O2 foram conduzidos com o único objetivo de polimento do efluente para reuso pelo processo. Desta maneira, o pH utilizado foi o natural do efluente (7,5) e três doses de H2O2 foram aplicadas, 4,0 g/L, 5,0 g/L e 6,0 g/L estando estas em excesso. / [en] The present work evaluates the use of two different types of AOP: the Zero-Fenton - process using zero valent iron - and UV/H2O2 for the treatment of pulp mill wastewater biologically treated. The observed parameters were BOD, COD, TOC, color and ABS280nm (measure of lignin compounds). The experiments were conducted in batch, lab scale and with real wastewater from biological treatment of a cellulose plant in Brazil. For the Fenton process, experiments were carried out according to a factorial design 23 investigating the influence of the variables pH, hydrogen peroxide dosage and zero-valent iron mass supplied by solution volume. As iron source, commercial steel wool was used in the concentrations of 5.5 g / L, 6.5 g / L and 7.5 g / L. The concentrations of hydrogen peroxide studied were 456.9 mg / L, 913.7 mg / L and 1370.6 mg / L and pH values ranged from 5.5, 6.5 and 7.5. The average removal rate was 57.1 per cent COD, 67.2 per cent COD, 90.5 per cent Color, 83.4 per cent lignin compounds and 54 per cent TOC. Also 9,52 mg/L of final BOD and 60,1 mg/L of final COD. The trials with the UV/H2O2 system, on the other hand, were conducted with the sole objective of polishing the effluent for reuse in the process. The pH used was the effluent s natural (7.5) and three excess doses of H2O2 were applied.
1454

Development of an Image Processing Tool for Fluorescence Microscopy Analysis of Paper Chemistry

Nyflött, Åsa January 2010 (has links)
Paper making today is, to some extent, based on empirical knowledge. It is wellknown that fines, pH, charge and ion strength affect the manufacture of paper. One way of extending knowledge of the mechanisms of paper chemistry is to follow the trajectories of fines and additives in the paper suspension to gather information as to the manner in which they react. Four tracking algorithms adapted to the needs of this particular problem were implemented in order to track particles effciently. The tracking algorithms include two variants of the well-known "Lucas-Kanade algorithm" and template matching techniques based on cross-correlation and least squares matching. Although these techniques are similar in principle, the actual tracking can nevertheless differ; the Lucas-Kanade algorithms were found to be more invariant to noise, whereas the cross-correlation and least squares methods are more rapid to execute in Matlab. The tracking methods have been evaluated using a simulator to generate image sequences of synthetic particles moving according to Brownian motion. Tracking has also been evaluated on microscope images of real latex particles where the results have been compared to manual tracking. Tracking of both the simulated particles and the latex particles resulted in similar results when compared to known position and manual tracking, respectively. / Tillverkning av papper är till en viss del baserad på empirisk kunskap. Välkänt är att finmaterial, pH värde, laddning och jonstyrka påverkar de papperskemiska mekanismerna och därmed flertalet pappersegenskaper vid tillverkning av papper. En möjlighet att utveckla kunskaperna inom papperskemiska mekanismerar att studera finmaterial och additiv i en pappers suspension for att samla in informationom reaktionsmekanismer. Fyra trackningalgoritmer ar vidareutvecklade i syftet att möjliggöra studier kring papperskemiska mekanismer. Trackningalgoritmerna inkluderar två varianter av den välkända "Lucas-Kanade" algoritm och två template-baserade metoder: korskorrelation och minsta kvadratmetoden. Samtliga metoder bygger på samma princip, men trots detta kan resultaten från trackningen skilja mellan metoderna. Lucas-Kanade algoritmerna är mer oberoende av brus medan korskorrelationen och minsta kvadratmetoden exekveras snabbare i Matlab. Trackning metoderna utvärderades med hjälp av en simulator som genererar bildsekvenser av syntetiska partiklar med en Brownsk rörelse. Trackningen har även använts på mikroskopibilder av rörelsebanor på verkliga suspenderade latex partiklar, varvid trackningresultatet har jämförts med manuell trackning. De genererade bildsekvensernapa de simulerade partiklarna har kända rörelsebanor som är jämförbara med rörelsebanor for latex partiklarna.
1455

Isolamento e cultura de células tronco mesenquimais da polpa dental e comparação de implantes dentários para cães estudos / Isolation and culture of stem cells mesenchymal of dental pulp and comparison of dental implants fro dogs studies in vitroin vitro

Aramburú Junior, Jaime Sardá 25 November 2015 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / This work was developed in two stages, described in scientific papers format. The goal of the first article was to adjust the techniques described in the literature for the isolation and culture of dental pulp cells to the physical and economic conditions of the research laboratory where the research was conducted. The methodology of this study was oriented by obtaining the pulp tissue from five deciduous teeth of dogs, which were digested in simple solution collagenase type 1 with positive results for the isolation. The outcome of the study was the isolation and cell culture of dental pulp with a lower cost and with enough cells for use in therapy. In the second study, the objective was to compare the in vitro resistance of dental implants with masticatory force dogs reported in the scientific literature. For materials and methods three different diameters dental implants 3.3mm, 4mm and 5mm were tested for static strength by applying compressive force on them. The result was a direct relationship to the resistance between the diameter and the applied force. Therefore, we can conclude that the method of isolation of dental pulp cells and culture of this study is similar to that described in the literature, but with the simplified methodology. And chewing strength of dogs can vary greatly, therefore we recommend possible the use of dental implants with a larger diameter. / Este trabalho foi desenvolvido em duas etapas, descritas no formato de artigos científicos. O objetivo do primeiro artigo foi ajustar às técnicas descritas na literatura para o isolamento e cultura da polpa dental para as condições físicas e econômicas do laboratório de pesquisa onde foi realizada a mesma. E a metodologia deste estudo foi orientada pela obtenção do tecido pulpar de cinco dentes decíduos de cães, que foram digeridos em solução simples de colagenase tipo 1 com resultados positivos para os isolamentos. O resultado do estudo foi o isolamento e cultura de células da polpa dental a um custo menor e com suficiente de células para utilização em terapia. No segundo estudo, o objetivo foi comparar a resistência in vitro de implantes dentários com cães de força mastigatória relatado na literatura científica. Para os materiais e métodos do estudo três diâmetros diferentes de implantes dental 3,3 mm, 4mm e 5mm foram testados quanto a resistência pela aplicação de força estática de compressão sobre eles. O resultado obtido foi de uma relação direta para a resistência entre o diâmetro e a força aplicada. Por isso, podemos concluir que o método de isolamento e cultura de células da polpa dental deste estudo é semelhante ao descrito na literatura, porém com a metodologia simplificada. E a força mastigatória dos cães pode variar, por isto é recomendado sempre que possível o uso de implante dental de maior diâmetro.
1456

Régénération de la pulpe dentaire par ingénierie tissulaire : mise au point d’une «pulpe équivalente» / Dental pulp regeneration by tissue engineering : making of a “pulp equivalent”

Souron, Jean-Baptiste 25 November 2013 (has links)
La pulpe dentaire est sujette à des lésions sévères faisant suite à une carie dentaire ou à un traumatisme. La thérapeutique conventionnelle préconisée alors est le traitement endodontique, qui consiste en l’exérèse de la totalité de la pulpe dentaire et le comblement de l’espace pulpaire par un matériau inerte. Ce traitement induit une fragilisation de la dent et une plus grande susceptibilité aux infections. Au cours de ce travail, nous avons mis au point une solution alternative, en proposant le remplacement de la pulpe dentaire lésée par une « pulpe équivalente » constituée de cellules souches mésenchymateuses de la pulpe ensemencées dans une matrice de collagène. Nous avons testé ce substitut pulpaire au travers d’un modèle de pulpotomie de la molaire chez le rat, à savoir l’exérèse de la totalité du parenchyme de la chambre pulpaire et conservation du réseau vasculaire radiculaire, où nous avons implanté des « pulpes équivalentes ». Notre objectif étant notamment de déterminer le devenir des cellules souches pulpaires implantées dans la dent grâce à l’imagerie nucléaire, dans ce contexte de développement d’une thérapie cellulaire. Les cellules ont été marquées à l’111Indium-oxine préalablement à leur implantation. Nous avons montré que le marquage n'avait pas d'incidence sur la viabilité et la prolifération des cellules pulpaires. Le suivi du signal s’est fait par tomographie d'émission monophotonique, couplée à un scanner spécifique du petit animal (NanoSPECT/CT, Bioscan), hebdomadairement pendant 3 semaines. Nous avons mis en évidence que l'intensité du signal SPECT était directement liée à l'intégrité des cellules, puisque que les matrices implantées avec des cellules marquées puis lysées par choc isotonique présentaient une diminution rapide de l’intensité du marquage. Grâce à la sensibilité de la méthode d’imagerie choisie, nous avons montré l’absence de diffusion majeure des cellules dans la circulation sanguine à partir du site d'implantation, ce qui pourrait constituer un risque de minéralisation ectopique lié à l’implantation de cellules souches mésenchymateuses. Par ailleurs, l’étude par histologie des processus de réparation et régénération de la pulpe dans les dents de rat a mis en évidence une prolifération abondante de cellules de type fibroblastique au sein des matrices, ainsi que la présence de nombreux vaisseaux et de nerfs dans la matrice cellularisée et à proximité. Ces résultats, non observés dans les matrices implantées avec des cellules lysées, suggéraient donc une fonctionnalité du tissu reconstruit et suggéraient que les cellules pulpaires implantées favorisaient une néovascularisation rapide de la pulpe équivalente, vraisemblablement en induisant un recrutement de cellules endothéliales à partir du réseau vasculaire radiculaire résiduel. / The dental pulp is prone to severe injuries following a tooth decay or trauma. Conventional recommended therapy is the endodontic treatment, which consists in the removal of all of the dental pulp and filling of the pulp space with an inert material. This treatment leads to a weakening of the tooth and a greater susceptibility to infection.In this work, we have developed an alternative solution, proposing the replacement of the injuried dental pulp by an " pulp equivalent " consisting of mesenchymal stem cells from the pulp seeded in a collagen matrix . We tested this pulp substitut through a model of the molar pulpotomy in rats, ie. the removal of the entire parenchyma of the pulp chamber and preservation of the root vascular network and implantation of the pulp equivalent. Our aim was to determine the fate of pulp stem cells implanted in the tooth by nuclear imaging in the context of developing a cell therapy. The cells were labeled with 111Indium - oxine prior to their implantation. We have shown that the labelling had no effect on the viability and proliferation of pulp cells. The signal tracking was done by single photon emission tomography , coupled with a specific small animal scanner ( NanoSPECT / CT , Bioscan ) weekly for 3 weeks. We demonstrated that the intensity of SPECT signal was directly related to the integrity of the cells, since the lysed labeled cells by isotonic shock showed a rapid decrease in the intensity of labeling . Due to the sensitivity of the chosen imaging method , we have shown the absence of major diffusion cells into the bloodstream from the site of implantation, which could result in a risk of ectopic mineralization related to the implementation of mesenchymal stem cells.Furthermore, the study by histology repair processes and regeneration of the pulp in teeth rat showed abundant proliferation of fibroblast-like cells within the matrix , and the presence of numerous vessels and nerves in matrix cellularized. These results , not observed in the matrices implanted with lysed cells, thus suggesting a feature of the reconstructed tissue and suggested that the pulp cells implanted favored a rapid neovascularization equivalent pulp, presumably by inducing the recruitment of endothelial cells from the residual root vascular network.
1457

Dilute acid catalysed hydrolysis of cellulose – extension to formic acid

Kupiainen, L. (Laura) 04 December 2012 (has links)
Abstract New methods are being sought for the production of chemicals, fuels and energy from renewable biomass. Lignocellulosic biomass consists mainly of cellulose, hemicellulose and lignin. Cellulose and hemicellulose can be converted to their building blocks, i.e. sugars, via hydrolysis. This thesis is focused on glucose production from cellulose by dilute acid hydrolysis. Acid hydrolysis has the drawback of limited glucose yields, but it has the potential to become a short-term solution for biochemical production. During acid hydrolysis, the cellulose chain is split into glucose, which undergoes further decomposition reactions to hydroxymethylfurfural, levulinic acid, formic acid and by-products like insoluble humins. The present thesis aims to increase our knowledge on complicated acid-catalysed hydrolysis of cellulose. Glucose decomposition and cellulose hydrolysis were studied independently in laboratory experiments. Kinetic modelling was used as a tool to evaluate the results. The effect of the hydrogen ion on the reactions was evaluated using formic or sulphuric acid as a catalyst. This thesis provides new knowledge of cellulose hydrolysis and glucose decomposition in formic acid, a novel catalyst for high-temperature dilute acid hydrolysis. Glucose yields from cellulose hydrolysed in formic or in sulphuric acid were comparable, indicating that a weak organic acid could function as a cellulose hydrolysis catalyst. Biomass fibres in the form of wheat straw pulp were hydrolysed more selectively to glucose than a model component, microcrystalline cellulose, using formic acid. Glucose decomposition took place similarly in formic and sulphuric acid when the temperature dependence of the hydrogen ion concentration was taken into account, but a significant difference was found between the reaction rates of cellulose hydrolysis in formic acid and in sulphuric acid. The observations can be explained by changes in the cellulose hydrolysis mechanism. Thus, it is proposed in this thesis that side-reactions from cellulose to non-glucose compounds have a more significant role in the system than has earlier been understood. / Tiivistelmä Uusia menetelmiä etsitään kemikaalien, polttoaineiden ja energian valmistamiseen uusiutuvasta biomassasta. Eräs biomassa, ns. lignoselluloosa, koostuu pääasiassa selluloosasta, hemiselluloosasta ja ligniinistä. Selluloosa ja hemiselluloosa voidaan muuttaa hydrolyysin avulla niiden rakennuspalikoikseen eli sokereiksi. Tämä väitöskirja keskittyy glukoosin tuottamiseen selluloosasta laimean happohydrolyysin menetelmällä. Happohydrolyysi kärsii rajoittuneesta glukoosin saannosta, mutta sillä on potentiaalia tulla lyhyen aikavälin ratkaisuksi biokemikaalien tuotannossa. Happohydrolyysin aikana selluloosaketju pilkkoutuu glukoosiksi, joka reagoi edelleen hajoamisreaktioiden kautta hydroksimetyylifurfuraaliksi, levuliini- ja muurahaishapoiksi ja kiinteäksi sivutuotteeksi. Tämän tutkimuksen tavoitteena on kasvattaa ymmärrystämme monimutkaisesta happokatalysoidusta selluloosan hydrolyysistä. Glukoosin hajoamista ja selluloosan hydrolyysiä tutkittiin erikseen laboratoriokokein. Kineettistä mallinnusta käytettiin työkaluna arvioimaan tuloksia. Vety-ionien vaikutus reaktioihin arvioitiin käyttämällä muurahais- ja rikkihappoja katalyytteinä. Tämä väitöskirja antaa uutta tietoa selluloosan hydrolyysistä ja glukoosin hajoamisreaktioista muurahaishapossa, joka on uusi katalyytti korkean lämpötilan laimean hapon hydrolyysissä. Glukoosisaannot muurahaishappo-hydrolysoidusta selluloosasta olivat vertailukelpoisia vastaaviin rikkihappo-hydrolyysi saantoihin. Tämä viittaa siihen, että heikko orgaaninen happo voisi toimia selluloosahydrolyysin katalyyttinä. Kun katalyyttinä käytettiin muurahaishappoa, vehnän oljesta tehdyt kuidut hydrolysoituivat selektiivisemmin glukoosiksi kuin mallikomponenttina toimineen mikrokiteisen selluloosan. Kun vetyionikonsentraation lämpötilariippuvuus otettiin huomioon, glukoosi hajosi samalla tavalla sekä muurahais- että rikkihappokatalyytissä, mutta merkittävä ero havaittiin selluloosahydrolyysin reaktionopeudessa. Havainnot voidaan selittää selluloosahydrolyysin mekanismissa tapahtuvilla muutoksilla. Väitöskirjassa esitetään, että sivureaktioilla selluloosasta ei-glukoosi-tuotteiksi on merkittävä vaikutus systeemiin.
1458

Mechanisms of thermomechanical pulp refining

Illikainen, M. (Mirja) 21 October 2008 (has links)
Abstract The objective of this thesis was to obtain new information about mechanisms of thermomechanical pulp refining in the inner area of a refiner disc gap by studying inter-fibre refining and by calculating the distribution of energy consumption in the refiner disc gap. The energy consumption of thermomechanical pulping process is very high although theoretically a small amount of energy is needed to create new fibre surfaces. Mechanisms of refining have been widely studied in order to understand the high energy consumption of the process, however, phenomena in the inner area of disc gap has had less attention. It is likely that this important position is causing high energy consumption due to the high residence time of pulp located there. The power distribution as a function of the refiner disc gap was calculated in this work. The calculation was based on mass and energy balances, as well as temperature and consistency profiles determined by mill trials. The power distribution was found to be dependent on segment geometry and the refining stage. However, in the first stage refiner with standard refiner segments, a notable amount of power was consumed in the inner area of the disc gap. Fibre-to-fibre refining is likely to be the most important mechanism in the inner area of disc gap from the point of view of energy consumption. In this work the inter-fibre refining was studied using equipment for shear and compression. Fibre-to-fibre refining was found to be an effective way to refine fibres from coarse pulp to separated, fibrillated and peeled fibres if frictional forces inside the compressed pulp were high enough. It was proposed that high energy of today’s thermomechanical pulping process could derive from too low frictional forces that heated pulp and evaporated water without any changes in fibre structure. The method to calculate power distribution and results of fibre-to-fibre refining experiments may give ideas for developing today’s thermomechanical pulp refiners’ or for developing totally new energy saving mechanical pulping processes.
1459

Intelligent information services in environmental applications

Räsänen, T. (Teemu) 22 November 2011 (has links)
Abstract The amount of information available has increased due to the development of our modern digital society. This has caused an information overflow, meaning that there is lot of data available but the meaningful information or knowledge is hidden inside the overwhelming data smog. Nevertheless, the large amount of data together with the increased capabilities of computers provides a great opportunity to learn the behaviour of different kinds of phenomena at a more detailed level. The quality of life, well-being and a healthy living environment, for example, are fields where new information services can assist the creation of proactive decisions to avoid environmental problems caused by industrial activity, traffic, or extraordinary weather conditions. The combination of data coming from different sources such as public registers, companies’ operational information systems, online sensors and process monitoring systems provides a fruitful basis for creating new valuable information for citizens, decision makers or other end users. The aim of this thesis is to present the concept of intelligent information services and a methodological background in order to add intelligence using computational methods for the enrichment of multidimensional data. Moreover, novel examples are presented where new significant information is created and then provided for end users. The data refining process used is called data mining and contains methods for data collection, pre-processing, modelling, visualizing and interpreting the results and sharing the new information thus created. Information systems are a base for the creation of information services, meaning that stakeholder groups have access only to information but they do not own the whole information system that contains measurement systems, data collecting, and a technological platform. Intelligence in information services comes from the use of computational intelligent methods in data processing, modelling and visualization. In this thesis the general concept of such services is presented and concretized using five cases that focus on environmental and industrial examples. The results of these case studies show that the combination of different data sources provides fertile ground for developing new information services. The data mining methods used such as clustering and predictive modelling together with effective pre-processing methods have great potential to handle the large amount of multivariate data in this environmental context also. A self-organizing map combined with k-means clustering is useful for creating more detailed information about personal energy use. Predictive modelling using a multilayer perceptron (MLP) is well suited for estimating the number of tourists visiting a leisure centre and to find the correspondence between pulp process characteristics and the chemicals used. These results have many indirect effects on reducing negative concerns regarding our surroundings and maintaining a healthy living environment. The innovative use of stored data is one of the main elements in the creation of future information services. Thus, more emphasis should be placed on the development of data integration and effective data processing methods. Furthermore, it is noted that final end users, such as citizens or decision makers, should be involved in the data refining process at the very first stage. In this way, the approach is truly customer-oriented and the results fulfil the concrete need of specific end users. / Tiivistelmä Informaation määrä on kasvanut merkittävästi tietoyhteiskunnan kehittymisen myötä. Käytössämme onkin huomattava määrä erimuotoista tietoa, josta voimme hyödyntää kuitenkin vain osan. Jatkuvasti mitattavan datan suuri määrä ja sijoittuminen hajalleen asettavat osaltaan haasteita tiedon hyödyntämiselle. Tietoyhteiskunnassa hyvinvointi ja terveellisen elinympäristön säilyminen koetaan aiempaa tärkeämmäksi. Toisaalta yritysten toiminnan tehostaminen ja kestävän kehityksen edistäminen vaativat jatkuvaa parantamista. Informaatioteknologian avulla moniulotteista mittaus- ja rekisteritietoa voidaan hyödyntää esimerkiksi ennakoivaan päätöksentekoon jolla voidaan edistää edellä mainittuja tavoitteita. Tässä työssä on esitetty ympäristöalan älykkäiden informaatiopalveluiden konsepti, jossa oleellista on loppukäyttäjien tarpeiden tunnistaminen ja ongelmien ratkaiseminen jalostetun informaation avulla. Älykkäiden informaatiopalvelujen taustalla on yhtenäinen tiedonlouhintaan perustuva tiedonjalostusprosessi, jossa raakatieto jalostetaan loppukäyttäjille soveltuvaan muotoon. Tiedonjalostusprosessi koostuu datan keräämisestä ja esikäsittelystä, mallintamisesta, tiedon visualisoinnista, tulosten tulkitsemisesta sekä oleellisen tiedon jakamisesta loppukäyttäjäryhmille. Datan käsittelyyn ja analysointiin on käytetty laskennallisesti älykkäitä menetelmiä, josta juontuu työn otsikko; älykkäät informaatiopalvelut. Väitöskirja pohjautuu viiteen artikkeliin, joissa osoitetaan tiedonjalostusprosessin toimivuus erilaisissa tapauksissa ja esitetään esimerkkejä kuhunkin prosessin vaiheeseen soveltuvista laskennallisista menetelmistä. Artikkeleissa on kuvattu matkailualueen kävijämäärien ennakointiin ja kotitalouksien sähköenergian kulutuksen pienentämiseen liittyvät informaatiopalvelut sekä analyysi selluprosessissa käytettävien kemikaalien määrän pienentämiseksi. Näistä saadut kokemukset ja tulokset on yleistetty älykkään informaatiopalvelun konseptiksi. Väitöskirjan toisena tavoitteena on rohkaista organisaatioita hyödyntämään tietovarantoja aiempaa tehokkaammin ja monipuolisemmin sekä rohkaista tarkastelemaan myös oman organisaation ulkopuolelta saatavien tietolähteiden käyttämistä. Toisaalta, uudenlaisten informaatiopalvelujen ja liiketoimintojen kehittämistä tukisi julkisilla varoilla kerättyjen, ja osin yritysten hallussa olevien, tietovarantojen julkaiseminen avoimiksi.
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Modifications chimiques des hémicelluloses pour une application papetière / Hemicellulose cationisation and application in paper pulp

Bigand, Virginie 04 November 2011 (has links)
Dans les procédés classiques d'extraction de la cellulose pour la fabrication de la pâte à papier à partir de bois, les hémicelluloses sont dégradées et sont brûlées pour alimenter l'usine en énergie. En incluant une étape préalable d'extraction de ces polysaccharides, ils pourraient alors être réintroduits en aval du procédé, après cationisation, en tant qu'agent de renfort dans la pâte à papier. Dans ce travail, la cationisation de deux hémicelluloses modèles commerciales de type galactomannane et xylane a été effectuée par éthérification avec un époxyde cationique en solution aqueuse basique, avec des degrés de substitution de 0,1 à 1,3. Les paramètres prépondérants de la réaction sont la concentration des espèces et la quantité d'agent éthérifiant, tandis que la température et le temps de réaction influent principalement sur le rendement massique. Un plan d'expérience a permis de modéliser l'interaction entre les quantités de soude et d'époxyde et d'optimiser les conditions en fonction du DS avec une efficacité de réaction de 50%. La cationisation a également été appliquée à deux hémicelluloses extraites au FCBA. La mise en oeuvre de la réaction en absence de solvant a permis d'atteindre une efficacité de réaction de 70 à 90% et de réduire considérablement les quantités de réactif utilisées et d'effluents à traiter. Parmi la gamme de DS, les dérivés cationiques de DS 0,3 ont donné les meilleures propriétés après ajout dans la pâte à papier, le galactomannane étant plus efficace que le xylane. Enfin, la réticulation des chaînes du xylane extrait a permis d'augmenter les propriétés physiques du papier de 15% supplémentaires / With current paper pulp processes, hemicelluloses are decomposed during the extraction of cellulose fibres. By including a previous step of hemicellulose extraction, these compounds could be reused as additives in the paper pulp, instead of cationic starch. In this work, two model galactomannan and xylan hemicelluloses were cationized in aqueous solution under basic conditions by etherification with a cationic epoxide. Degrees of substitution from 0.1 to 1.3 were obtained. Species concentration and epoxide amount appeared as preponderant parameters of the reaction. With an experimental design, the interaction between sodium hydroxide and epoxide amounts was modelized, and reactional conditions were optimized depending on the desired DS with a reaction efficiency of 50%. Then, cationisation was applied to two hemicelluloses extracted in FCBA. The reaction was also carried out in absence of solvent with a reaction efficiency of 70-90%, by minimising reagents consumption and effluents. Cationic derivatives with DS 0.3 gave the best performance to increase the paper resistance when they were added in paper pulp, galactomannan being more efficient than xylan. Chain reticulation allowed increasing mechanical properties of paper of 15% for the extracted xylan

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