Growing environmental awareness has led to developments within landfill engineering, increasing the amount of research with the aim of constructing safe, stable landfills with optimal geometry. EU member states are forced to improve waste disposal policies through directives (Council of the European Union 1999) enforced in member countries through local legislation (in the UK, The Landfill (England and Wales) Regulations 2002). This research focuses on several aspects of waste barrier in situ performance. A field study was conducted on a landfill side slope to investigate geosynthetics mechanical behaviour in service conditions and on a landfill capping to investigate capping geosynthetic drainage system performance in situ conditions and pore water distributions along the capping. Further site derived data were collected in order to validate numerical modelling approaches, to increase confidence in a design processes and to investigate mechanisms incorporated in the liner s performance. The side slope studies revealed an additional factor affecting lining components displacement along the slope: geomembrane and geotextile response to atmospheric conditions. The capping study allowed production of recommendations for future capping designs. These can be used to considerably enhance capping stability.

Im Rahmen des Forschungsprojektes wurden zwei Verfahren zur Herstellung thermisch modifizierter Furniere entwickelt. Nach Verfahren 1 erfolgt die Herstellung von Furnier durch Messern von thermisch modifizierten Blöcken, wobei der Hauptanteil der Untersuchungen an längs gemesserten Furnieren durchgeführt wurde. Ein Industrieversuch belegt die Machbarkeit der Herstellung thermisch modifizierter Furniere aus modifizierten Blöcken durch quer messern, also nach dem üblichen Verfahren zur Herstellung dekorativer Furniere. Nach Verfahren 2 erfolgt die Herstellung von thermisch modifizierten Furnieren durch thermische Modifizierung handelsüblicher dünner Messerfurniere (d=0,5...0,6 mm). Parameter für eine thermische Modifikation sind im Wesentlichen die Dauer der Behandlung sowie die Temperatur. Die Temperatur wurde im Bereich zwischen 170°C und 210°C variiert, die Dauer der Hochtemperaturbehandlung zwischen 2 h und 4 h. Als Holzarten wurden Rotbuche, Ahorn, Birke, Pappel und Esche untersucht. Die hergestellten Furniere wurden hinsichtlich verschiedener mechanischer Eigenschaften, farblicher Eigenschaften sowie verarbeitungstechnischer Eigenschaften untersucht und bewertet.

Wood is a natural and renewable resource and, moreover, a most decorative and beautiful material. Most valuable logs are used for veneer production for optimum exploitation and utilization. Attractive wood veneers adorn any surface and is primarily used for furniture, yacht and automotive interior works. However, such application of wood veneer is limited to rather simply shaped carrier components due to the veneer’s mechanical restrictions. Previously, several approaches have been discussed to flexibilize wood allowing a greater deformation, but none approach has been entirely satisfactory. On that score, another veneer modification process has been suggested comprising a furfuryl alcohol impregnation to plasticize the wood veneer realizing enhanced veneer flexibility and mouldability (Pfriem and Buchelt 2011b). In the presence of a suitable initiator and promoted by elevated temperatures, furfuryl alcohol forms a very hard, insoluble polymer inside the wood cell walls. If polymerization is initiated as the impregnated veneer is moulded, the polymer is assumed to fix the gained shape. This thesis summarizes experimental work investigating the effect of furfuryl alcohol modification on maple veneer plasticization, shape fixation, and shape stability and the impact of various process parameters on material characteristics. Veneer samples impregnated with furfuryl alcohol exhibited an increased cell wall swelling, were notably softer than dry reference veneer, and showed an enhanced mouldability comparable to water impregnated veneer samples. Each characteristic is indicative for an increased plasticization. DSC studies were carried out to assess the influence of various initiator contents and ethanol dilutions of the impregnation liquid on the curing reactions and the retained polymer yield. Thereby, high initiator contents promoted a more rapid curing at lower temperatures with higher polymer yields, whereas higher dilution shifted the curing towards higher temperatures and possibly retard the curing resulting in lower polymer yields. The furfuryl alcohol polymer retaining inside the cell walls was proved to fix the achieved shape of veneer providing moreover enhanced shape stability at elevated temperatures and increasing moisture compared to unmodified reference veneer samples. According to these findings, furfuryl alcohol modification can be used for wood veneer plasticization and improved mouldability, shape fixation, and stabilization. However, material properties vary notably with changing process parameters. / Holz ist nicht nur eine natürlicher und nachwachsender Rohstoff, sondern vielmehr auch ein sehr dekoratives und schönes Material. Die wertvollsten Baumstämme werden daher häufig zur Furnierproduktion genutzt, um diese raren Stämme bestmöglich auszunutzen und zu verwerten. Besonders schöne Furniere schmücken jegliche Oberfläche und werden vorallem in der Möbelindustrie, sowie beim Yacht- und Autoinnenausbau verwendet. Jedoch ist die Anwendung aufgrund mechanischer Restriktionen auf eher einfach geformte Oberflächen und Trägerteile begrenzt. In der Vergangenheit wurden unterschiedliche Methoden entwickelt, um den Einsatzbereich von Furnieren durch eine erhöhte Flexibilität und Verformbarkeit auszuweiten, jedoch ist keiner dieser Prozesse in allen Aspekten zufriedenstellend. Aus diesem Grund wurde von Pfriem und Buchelt (2011b) eine neue Methode vorgeschlagen. Hierbei sollen Furniere mit Furfurylalkohol imprägniert werden, um einerseits die Furniere zu plastifizieren und eine erhöhte Flexibilität und Umformbarkeit zu ermöglichen. Andererseits härtet Furfurylalkohol in Gegenwart eines geeigneten Initiators und durch erhöhte Temperaturen begünstigt aus und bildet in den Zellwänden ein hartes, weitestgehend unlösliches Polymer aus. Hierbei wird angestrebt, die Polymerisation zu initiieren, wenn das imprägnierte Furnier bereits umgeformt ist, so dass das entstehende Polymer das Furnier im umgeformten Zustand fixiert. Die vorliegende Dissertation fasst die erzielten Ergebnisse von Experimenten zusammen, die durchgeführt wurden, um die plastifizierende Wirkung von Furfurylalkohol auf Ahornfurniere sowie die formfixierende und stabilisierende Eigenschaft des ausgehärteten Polymers zu untersuchen und den Einfluss unterschiedlicher Prozessparameter auf erzielte Materialeigenschaften zu bestimmen. Es konnte nachgewiesen werden, dass durch die Imprägnierung mit Furfurylalkohol ein Quellen der Zellwände verursacht wird und dass die getränkten Proben deutlich weicher sind als die Referenzproben und eine erhöhte Umformung aufwiesen. Diese erzielten Änderungen weisen auf eine deutliche Plastifizierung der Holzsubstanz hin. DSC-Analysen von Furnieren, die mit unterschiedlich zusammengesetzten Imprägnierflüssigkeiten auf Basis von Furfurylalkohol imprägniert wurden, belegen den Einfluss unterschiedlicher Initiatoranteile und Verdünnungen mit Ethanol auf die Polymerisation. Während höhere Anteile an Initiator eine rasche Reaktion bei niedrigeren Temperaturen und einen hohen Beladungsgrad hervorrufen, bewirken starke Verdünnungen des Furfurylalkohols mit Ethanol eine Verzögerung der Polymerisation und eine Verschiebung dieser zu höheren Temperaturen bei gleichzeitigen vergleichsweise geringen Beladungsgraden. Mit weiteren Versuchen konnte bestätigt werden, dass das Polymer des Furfurylalkohols in den Zellwänden die erzielte Umformung der Furniere fixiert und auch bei höheren Temperaturen und Luftfeuchten eine erhöhte Formstabilität bewirkt. Die Versuche haben gezeigt, dass Furfurylalkohol zur Plastifizierung und verbesserten Umformbarkeit von Furnieren sowie zu deren Formfixierung und Formstabilisierung genutzt werden kann, allerdings variieren die Materialeigenschaften mit unterschiedlichen Prozessparametern insbesondere mit unterschiedlichen Initiatoranteilen in der Imprägnierflüssigkeit.

O objetivo deste trabalho é analisar in vitro a dissipação de tensões em incisivos centrais superiores humanos restaurados com facetas de cerâmica feldspática, através da análise do método dos elementos finitos, considerando cargas funcionais de mastigação e corte dos alimentos, em função de três tipos de preparos utilizados: sem proteção incisal; com proteção incisal em ângulo e com proteção incisal em degrau palatino. Foram utilizadas modelagens bidimensionais de um incisivo central superior e suas estruturas de suporte, simulando três situações: (Primeira modelagem) incisivo central superior com desgaste vestibular (em forma de janela); (Segunda modelagem) incisivo central superior com desgaste vestibular e proteção incisal em plano inclinado; (Terceira modelagem) incisivo central superior com desgaste vestibular, e proteção incisal com degrau palatino. Foi considerada uma carga (P=100N) com uma inclinação de 45 concentrada, simulando a região de contato do incisivo central inferior com o superior durante a mastigação e uma na região de contato topo a topo dos incisivos superior e inferior, simulando o corte dos alimentos. Após a análise dos dados obtidos pela distribuição de tensões, pode-se concluir que quanto à dissipação das tensões em todo o sistema proposto, com a aplicação de carga em 45, não foram observadas mudanças no estado tensional nos três diferentes preparos. Quando foi aplicada carga vertical, simulando o contato de topo, houve variação no estado tensional no sistema do dente com preparo em janela. Nas facetas, com a aplicação de carga em 45, nos preparos em janela e com proteção incisal em plano inclinado o resultado foi semelhante nos valores tensionais enquanto, nas facetas em dentes preparados com proteção incisal com degrau palatino, a distribuição foi mais homogênea tendo valores superiores, mostrando que o abraçamento do dente diminuiu a flexão. / The aim of this study is to analyze in vitro stress dissipation on human maxillary central incisors restored with ceramic feldspathic veneers, through the finite element method. Functional chewing and food cutting loads were evaluated in three types of preparations of teeth: preparation without incisal protection, with incisal angle protection and with incisal protection with palatal step. Two-dimensional modeling of a maxillary central incisor and its supporting structures were used, simulating three conditions: 1) First modeling - maxillary central incisor with facial preparation (window shape); 2) Second modeling - maxillary central incisor with facial preparation and incisal protection on an inclined plane; 3) Third modeling - maxillary central incisor with facial preparation and incisal protection with palatal step. The chosen load (P = 100N) was applied to two different points: one of them to the palatal aspect with an inclination of 45 in order to simulate the contact area of the mandibular and the maxillary central incisors during chewing and the other one to the region of contact with edge-to-edge upper/lower central incisors, simulating food cutting. After analyzing the data obtained from the stress distribution it is possible to conclude that there are no alterations in tensional characteristics of the three different preparations concerning the stress dissipation on the whole proposed system, considering the application of load in 45. When the vertical load was applied, simulating an edge-to-edge contact, a variation in the stress state of tooth with window preparation was observed. For veneers with 45 load application, both the window preparation teeth and teeth with incisal protection on an inclined plane presented similar tensional values. For veneers of prepared teeth with incisal protection with palatal step, the stress distribution was more homogeneous with higher values, showing that tooth embracement reduced flexion.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-06-13T13:02:47Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação Erica Andrade Borges.pdf: 4139502 bytes, checksum: c80b9b1a5c5ba294663e2fd676cb075a (MD5) / Made available in DSpace on 2016-06-13T13:02:47Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação Erica Andrade Borges.pdf: 4139502 bytes, checksum: c80b9b1a5c5ba294663e2fd676cb075a (MD5) Previous issue date: 1201-02-11 / CAPEs / O objetivo deste estudo foi validar o uso da técnica da tomografia por coerência óptica através de experimento in vitro para avaliar a cimentação e a linha de união laminado-cimento-dente antes e depois da termociclagem, visando a aplicação clínica deste instrumento. Além de comparar diferentes modalidades de materiais e protocolos de cimentação. A técnica da tomografia por coerência óptica (TCO) é um método não invasivo, quantitativo e qualitativo, e foi utilizado para avaliação da qualidade póscimentação do laminado, minimizando possíveis erros, e proporcionando acompanhamento clínico sem exposição a radiação ou qualquer procedimento invasivo. Foram feitas imagens em 2D e 3D dos laminados e das superfícies dentais antes e depois da cimentação e do processo de ciclagem térmica. Os laminados (20) foram cimentados na superfície de esmalte bovino de acordo com uma distribuição aleatória em 4 grupos (n=05): FA – cimento resinoso dual com fotoativação prévia do adesivo; FC – cimento resinoso dual sem fotoativação prévia do adesivo; AF - cimento resinoso autocondicionante dual com fotoativação; AQ - cimento resinoso autocondicionante dual com polimerização química. Os laminados foram fabricados em porcelana modificada por dissilicato de lítio, na espessura de 0,5 mm. As análises foram feitas através de imagens 2D e 3D com o TCO. Os resultados mostraram claramente a presença de bolhas com dimensões típicas que variaram de 146 μm a 1427 μm, além de falhas como a presença de gap e até a desadaptação do laminado. Parte dessas falhas, já estavam presentes imediatamente após o processo de cimentação e após a ciclagem térmica mantiveram-se estáveis ou foram acentuadas. Os resultados indicam que um acompanhamento periódico de pacientes que utilizam laminados cerâmicos é de fundamental importância para garantia da manutenção da qualidade do procedimento, bem como evitar problemas na saúde bucal. Propomos então a técnica de TCO como padrão para este procedimento. / The aim of this study was to validate the use of optical coherence tomography (OCT) through in vitro experiment to evaluate the cementing and the union line of lumineer-cement-tooth before and after the thermal cycling. In addition to comparing different types of materials and cementation protocols. The technique of optical coherence tomography (OCT) is a noninvasive, quantitative and qualitative method, and was used to evaluate the postcementation quality of the lamina, minimizing potential errors, and providing clinical follow-up without exposure to radiation or any invasive procedure. Were made in both 2D and 3D imaging of tooth surfaces and the laminate before and after the cementing and the thermocycling process. 20 specimens of lumineers-teetth were prepared in bovine teeth and randomly allocated in 4 experimental groups (n=5) with two different cementation techniques and two different types of cementing agent: FA - dual resin cement with prior photo activation of the adhesive; FC - dual resin cement without curing the adhesive; AF - self-etching resin cement with photoactivation; AQ - selfetching resin cement with chemical polymerization. The lumineers were made of lithium disilicate and obtained using a vacuum injection technique, thickness of 0.5 mm. The analysis was performed by using 2D and 3D OCT images, obtained before and after the thermal cycling. The results showed the presence of bubbles with typical size ranging from 146 μm to 1427 μm, and faults as the presence of gap and laminate mismatch. Some of these faults were already present immediately after the process of cementing and after thermal cycling remained stable or were marked. The results indicate that regular monitoring of patients using lumineers is of fundamental importance for ensuring the maintenance of the quality of the procedure and how to avoid problems in oral health. Then we propose the OCT technical default for this in vivo to follow-up.

O presente trabalho teve como objetivo avaliar o potencial de utilização da madeira do híbrido Pinus elliottii var. elliottii x Pinus caribaea var. hondurensis para a produção de lâminas e manufatura de painéis compensados. Para realização do estudo foram utilizadas 10 toras de 1,30 m de comprimento, provenientes de 5 árvores coletadas aos 7 anos e 10 meses de idade nos plantios da empresa Pinus Brasil, localizada em Buri - SP. O rendimento do processo de laminação das toras e a qualidade das lâminas produzidas foram avaliados. O delineamento para a produção experimental e avaliação dos painéis compensados constituiu-se de 8 tratamentos arranjados em esquema fatorial, através dos quais foram analisados os efeitos de duas posições de retirada da tora no tronco (A e B), duas gramaturas de adesivo (380 e 420g/m²) e dois tempos de prensagem (8 e 12 minutos). Para cada tratamento foram produzidos 3 painéis compensados, cada qual com 5 lâminas coladas entre si com adesivo à base de fenol-formaldeído. O rendimento médio do processo de laminação das toras, sem casca, foi de aproximadamente 53%, podendo ser considerado bom e compatível com outros resultados encontrados na literatura. As toras A, mais próximas da base das árvores, produziram maior número de lâminas, no entanto, de qualidade inferior em relação às lâminas das toras (B). A massa específica aparente dos painéis estudados foi relativamente baixa em comparação a outros compensados de Pinus, cuja propriedade apresentou valor médio estatisticamente superior para os compensados confeccionados com lâminas das toras A. Os painéis apresentaram boa estabilidade dimensional, sendo que o tempo de prensagem de 12 minutos para a produção dos compensados resultou em diminuição estatisticamente significativa do inchamento em espessura. O tempo de prensagem, gramatura de adesivo e posição da tora influenciaram os valores de resistência da colagem dos painéis, sendo que os maiores valores foram observados para os painéis produzidos com lâminas das toras B, tempo de prensagem de 12 minutos e gramatura de 420g/m². Os valores médios do módulo de ruptura (MOR) e do módulo de elasticidade (MOE) à flexão estática dos painéis foram, respectivamente, compatíveis e inferiores quando comparados com os do Catálogo Técnico n°1 Compensados de Pinus (ABIMCI, 2002). Houve efeito do fator posição da tora no MOR paralelo dos painéis e o maior valor médio foi observado para os compensados confeccionados com lâminas das toras da posição A. Houve interação entre os fatores posição da tora e tempo de prensagem para o MOR e MOE perpendiculares, sendo que, de modo geral, os menores valores foram observados para os compensados confeccionados com lâminas das toras B e prensados no tempo de 12 minutos. Conclui-se que a madeira do híbrido estudado apresenta bom potencial para a produção de lâminas e manufatura de compensados. Porém, o emprego desses painéis em produtos que requeiram elevados valores do MOR e do MOE, por exemplo, em formas de concreto, não é aconselhável, porque esses painéis não satisfariam tais requisitos. / The main objective of this work was to evaluate the potential of wood utilization from Pinus elliottii var. elliottii x Pinus caribaea var. hondurensis hybrid for veneer production and plywood manufacturing. This study used 10 logs measuring 1.30m in length, obtained from 05 trees, 07 years and 10 months of age, from plantations located in Buri SP, Brazil. Peeling process yield and quality of veneers produced were evaluated. The experimental design consisted of eight treatments, arranged in a factorial way, being the effects of two log positions (A and B) on the trunk, two adhesive spread rates (380 and 420g/m²) and two press times (8 and 12 minutes). Three plywood panels were produced for each treatment and each panel was constituted of 05 veneers glued with an adhesive based on phenol-formaldehyde. The peeling process yield was approximately 53%, based on logs without bark, and can be considered good and compatible with other results found in the literature. The logs A, closer to the base of the tree, produced a greater number of veneers, but of inferior quality compared to the logs B veneers. The apparent specific mass of the plywood panels was relatively low, compared to other Pines plywood available in the literature, with a superior mean value for the plywood made with veneers of logs A comparing to logs B. The plywood panels showed good dimensional stability. The press time of 12 minutes resulted in significant thickness swelling decrease and the press time, adhesive spread rate and log position, influenced the bonding line strength. The best results of bonding line strength were obtained for the plywood produced with logs B veneers, press time of 12 minutes and spread rate of 420g/m². The static bending properties of the plywood panels studied, modulus of rupture (MOR) and modulus of elasticity (MOE),were compatible and inferior, respectively, compared to other Brazilian-pines plywood. There was an effect of the log position factor on the MOR-parallel-to-grain with best results obtained for plywood panels produced with veneers of logs A. There was interaction between the log position and press time factors on the MOR and MOE, both perpendicular-to-grain, with the lowest values observed for plywood panels produced with log B veneers and press time of 12 minutes. The hybrid pine wood studied has good potential for veneer production and plywood manufacturing. However, the use of these panels in products that require high values of MOR and MOE, for example, in formwork is not advisable, because these panels do not satisfy these requirements.

Pour répondre à la demande croissante de bois et pour préserver les forêts primaires, les méthodes de sylviculture les plus dynamiques ont été privilégiées de manière générale sur la planète.. Les objectifs de la recherche étaient 1) déterminer le point de démarcation/ âge de transition entre le bois juvénile et le bois mature sur sengon (Falcataria moluccana), jabon(Anthocephalus cadamba Miq.), peuplier (Populus sp) et douglas (Psedotsuga menziesii); 2) analyser l'effet de la juvénilité sur un fissuration cyclique, la rugosité et de mouillage; 3) analyser l'effet de la fissuration cyclique et juvénilité sur la résistance à l'adhérence de la colle et les propriétés mécaniques du LVL en flexion; et 4) appliquer un nouveau modèle analytique pour estimer la variation du module d'élasticité du lamibois (sengon et jabon) depuis la moelle vers l'écorce. A partir de la longueur des fibres, le point de démarcation entre le bois juvénile et le bois mature ont été estimés. Pour les essences sengon and jabon, les placages obtenus à partir du cœur des arbres, réputés juvéniles, sont plus fissurés plus rugueux et avec une haute mouillabilité comparativement à ceux obtenus à partir du bois près de l’écorce (plus mature). Une phase d’étuvage préliminaire des bois dans un bain d’eau chaude à 75°C pendant 4 heures a permis d’améliorer sensiblement la qualité des placages en diminuant la fissuration, la rugosité et s’accompagne d’une augmentation de la mouillabilité. La résistance à l'adhérence de la colle, et les modules élastiques et de rupture spécifiques (SMOE et SMOR) du LVL (jabon et sengon) diminuent à mesure que la fréquence de fissure augmente ou en partant de l'écorce vers la moelle. L'avantage de l'utilisation de placages en peuplier de bois mature a été prouvé avec une amélioration de 15 à 20% en moyenne pour les propriétés mécaniques, pour un poids de panneau comparable. Pour le douglas, l'utilisation de placages de bois mature dans la constitution des panneaux de LVL permet également d’améliorer les performances en flexion (de 7 à 22 % sur el MOR). Le modèle analytique a été utilisé afin de prédire les variations du module élastique allant de la moelle à l’écorce. Il permet à partir d’un grand nombre de combinaisons d’estimer le potentiel issu d’une ressource donnée. Pour le contexte de l’étude qui représente bien le potentiel sylvicole de l’Indonésie, la proportion de bois juvénile étant quasi-totale (100%), l’action de trier les placages n’est pas apparue comme pertinente. / The development of plantation and community forest to meet wood demand in society has produced fast growing wood species. The research objectives were 1) to determine demarcation point/transition age between juvenile and mature wood on sengon (Falcataria moluccana), jabon (Anthocephalus cadamba Miq.), poplar (Populus sp) and douglas fir (Psedotsuga menzii); 2) to analyze the effect of juvenility on lathe check, surface roughness and wettability; 3) to analyze the effect of lathe check and juvenility on glue bond strength and laminated veneer lumber (LVL) bending properties; and 4) to apply a new analytical model to determine the variation of specific MOE LVL values of sengon and jabon from pith to bark. Based on fiber length trait, the demarcation point between juvenile and mature wood were approximately at segmented rings 17th (sengon) and at segmented ring 24th (jabon). While, transition age of poplar cultivars and douglas-fir, transition age happened approximately at 12 years old and 18 years old, respectively. The results showed that wood near pith on sengon and jabon resulted veneers with higher lathe check, rougher surface and high wettability, while wood near bark resulted veneers with lower lathe check, smoother surface and low wettability. Glue bond strength, Specific MOE (SMOE) and Specific MOR (Modulus of Rupture) of sengon and jabon LVL were decreased as the frequency of lathe check increased or those strength values increased from pith to bark. The advantage of using poplar veneers from mature wood was proved with an improvement of 15 to 20% on average for mechanical properties, while for douglas-fir, was 7 to 22%. An analytical model was used to predict the variation of the LVL mechanical characteristics using different scenarios. According to the context of this study assumed to be close to the Indonesian resource there is no need to sort veneers since most of the tree is juvenile wood for logs no older than 7.

Wood is a natural and renewable resource and, moreover, a most decorative and beautiful material. Most valuable logs are used for veneer production for optimum exploitation and utilization. Attractive wood veneers adorn any surface and is primarily used for furniture, yacht and automotive interior works. However, such application of wood veneer is limited to rather simply shaped carrier components due to the veneer’s mechanical restrictions. Previously, several approaches have been discussed to flexibilize wood allowing a greater deformation, but none approach has been entirely satisfactory. On that score, another veneer modification process has been suggested comprising a furfuryl alcohol impregnation to plasticize the wood veneer realizing enhanced veneer flexibility and mouldability (Pfriem and Buchelt 2011b). In the presence of a suitable initiator and promoted by elevated temperatures, furfuryl alcohol forms a very hard, insoluble polymer inside the wood cell walls. If polymerization is initiated as the impregnated veneer is moulded, the polymer is assumed to fix the gained shape. This thesis summarizes experimental work investigating the effect of furfuryl alcohol modification on maple veneer plasticization, shape fixation, and shape stability and the impact of various process parameters on material characteristics. Veneer samples impregnated with furfuryl alcohol exhibited an increased cell wall swelling, were notably softer than dry reference veneer, and showed an enhanced mouldability comparable to water impregnated veneer samples. Each characteristic is indicative for an increased plasticization. DSC studies were carried out to assess the influence of various initiator contents and ethanol dilutions of the impregnation liquid on the curing reactions and the retained polymer yield. Thereby, high initiator contents promoted a more rapid curing at lower temperatures with higher polymer yields, whereas higher dilution shifted the curing towards higher temperatures and possibly retard the curing resulting in lower polymer yields. The furfuryl alcohol polymer retaining inside the cell walls was proved to fix the achieved shape of veneer providing moreover enhanced shape stability at elevated temperatures and increasing moisture compared to unmodified reference veneer samples. According to these findings, furfuryl alcohol modification can be used for wood veneer plasticization and improved mouldability, shape fixation, and stabilization. However, material properties vary notably with changing process parameters. / Holz ist nicht nur eine natürlicher und nachwachsender Rohstoff, sondern vielmehr auch ein sehr dekoratives und schönes Material. Die wertvollsten Baumstämme werden daher häufig zur Furnierproduktion genutzt, um diese raren Stämme bestmöglich auszunutzen und zu verwerten. Besonders schöne Furniere schmücken jegliche Oberfläche und werden vorallem in der Möbelindustrie, sowie beim Yacht- und Autoinnenausbau verwendet. Jedoch ist die Anwendung aufgrund mechanischer Restriktionen auf eher einfach geformte Oberflächen und Trägerteile begrenzt. In der Vergangenheit wurden unterschiedliche Methoden entwickelt, um den Einsatzbereich von Furnieren durch eine erhöhte Flexibilität und Verformbarkeit auszuweiten, jedoch ist keiner dieser Prozesse in allen Aspekten zufriedenstellend. Aus diesem Grund wurde von Pfriem und Buchelt (2011b) eine neue Methode vorgeschlagen. Hierbei sollen Furniere mit Furfurylalkohol imprägniert werden, um einerseits die Furniere zu plastifizieren und eine erhöhte Flexibilität und Umformbarkeit zu ermöglichen. Andererseits härtet Furfurylalkohol in Gegenwart eines geeigneten Initiators und durch erhöhte Temperaturen begünstigt aus und bildet in den Zellwänden ein hartes, weitestgehend unlösliches Polymer aus. Hierbei wird angestrebt, die Polymerisation zu initiieren, wenn das imprägnierte Furnier bereits umgeformt ist, so dass das entstehende Polymer das Furnier im umgeformten Zustand fixiert. Die vorliegende Dissertation fasst die erzielten Ergebnisse von Experimenten zusammen, die durchgeführt wurden, um die plastifizierende Wirkung von Furfurylalkohol auf Ahornfurniere sowie die formfixierende und stabilisierende Eigenschaft des ausgehärteten Polymers zu untersuchen und den Einfluss unterschiedlicher Prozessparameter auf erzielte Materialeigenschaften zu bestimmen. Es konnte nachgewiesen werden, dass durch die Imprägnierung mit Furfurylalkohol ein Quellen der Zellwände verursacht wird und dass die getränkten Proben deutlich weicher sind als die Referenzproben und eine erhöhte Umformung aufwiesen. Diese erzielten Änderungen weisen auf eine deutliche Plastifizierung der Holzsubstanz hin. DSC-Analysen von Furnieren, die mit unterschiedlich zusammengesetzten Imprägnierflüssigkeiten auf Basis von Furfurylalkohol imprägniert wurden, belegen den Einfluss unterschiedlicher Initiatoranteile und Verdünnungen mit Ethanol auf die Polymerisation. Während höhere Anteile an Initiator eine rasche Reaktion bei niedrigeren Temperaturen und einen hohen Beladungsgrad hervorrufen, bewirken starke Verdünnungen des Furfurylalkohols mit Ethanol eine Verzögerung der Polymerisation und eine Verschiebung dieser zu höheren Temperaturen bei gleichzeitigen vergleichsweise geringen Beladungsgraden. Mit weiteren Versuchen konnte bestätigt werden, dass das Polymer des Furfurylalkohols in den Zellwänden die erzielte Umformung der Furniere fixiert und auch bei höheren Temperaturen und Luftfeuchten eine erhöhte Formstabilität bewirkt. Die Versuche haben gezeigt, dass Furfurylalkohol zur Plastifizierung und verbesserten Umformbarkeit von Furnieren sowie zu deren Formfixierung und Formstabilisierung genutzt werden kann, allerdings variieren die Materialeigenschaften mit unterschiedlichen Prozessparametern insbesondere mit unterschiedlichen Initiatoranteilen in der Imprägnierflüssigkeit.

Im Rahmen des Forschungsprojektes wurden zwei Verfahren zur Herstellung thermisch modifizierter Furniere entwickelt. Nach Verfahren 1 erfolgt die Herstellung von Furnier durch Messern von thermisch modifizierten Blöcken, wobei der Hauptanteil der Untersuchungen an längs gemesserten Furnieren durchgeführt wurde. Ein Industrieversuch belegt die Machbarkeit der Herstellung thermisch modifizierter Furniere aus modifizierten Blöcken durch quer messern, also nach dem üblichen Verfahren zur Herstellung dekorativer Furniere. Nach Verfahren 2 erfolgt die Herstellung von thermisch modifizierten Furnieren durch thermische Modifizierung handelsüblicher dünner Messerfurniere (d=0,5...0,6 mm). Parameter für eine thermische Modifikation sind im Wesentlichen die Dauer der Behandlung sowie die Temperatur. Die Temperatur wurde im Bereich zwischen 170°C und 210°C variiert, die Dauer der Hochtemperaturbehandlung zwischen 2 h und 4 h. Als Holzarten wurden Rotbuche, Ahorn, Birke, Pappel und Esche untersucht. Die hergestellten Furniere wurden hinsichtlich verschiedener mechanischer Eigenschaften, farblicher Eigenschaften sowie verarbeitungstechnischer Eigenschaften untersucht und bewertet.

Master’s thesis focuses on area of historic water reservoirs on Yellow Hill, situated between streets of Tomešova and Tvrdého. They continued to supply Brno with non-potable water until 1997 and TIC is currently looking for a new way to make water reservoirs accesable and more interesting to the general public. Due to the existence of underground reservoirs the site has remained undeveloped and is covered with dense greenery. Thanks to that, the character of the place is in the context of the surrounding build-up area very unique. The proposal not only respects that, but seeks to support it. The whole area is undergoing through new landscape design and is completed by three single-storey pavilions, which with their various functions ensure the operation of the site. The historic buildings that were used to manage the underground reservoirs are renovated and integrated into the operation of the site. An important part of the design is also the solution of barrier-free access to reservoirs, their interconnection and installation of optical device - the Camery Obscury in the oldest of the reservoirs. The whole place becomes more accesible and attractive for visitors.