Doctor of Philosophy / Steam reconditioning to recover collapse, in mid to low density eucalypt species, has been known for over ninety years. The current industrial practices for steam reconditioning have largely been based on a few older studies, which were often poorly documented and based on very small sample sizes. On top of this, many local practices and ‘rules of thumb’ have developed over time, many of which have a questionable scientific basis. This thesis was undertaken to more rigorously investigate and fundamentally understand collapse recovery, and try to optimise its application. The most obvious variable that kiln operators have control over is the moisture content of the timber prior to steam reconditioning. Experiments were undertaken to generate a range of moisture gradients (ranging from minimal to more industrially realistic) to evaluate the effect of moisture content on collapse recovery. An optimal moisture content for the core of the boards was found to be between about 18–20%, although there was no statistical difference in recoveries between about 17–25% moisture content. Below 15% moisture content recovery dropped off severely and intra-ring internal checking closure was incomplete, while at 25% moisture content an increased level of normal shrinkage, due to the early removal of drying stresses, was the main drawback. Above a core moisture content of about 35% incomplete closure of intra-ring internal checks was again observed. There was little evidence of re-collapse occurring in these high moisture content samples. Previously established relationships between density and collapse and drying rate were again generally observed in these experiments. However, for the first time an effect of collapse in reducing the fitted drying diffusion coefficients was also observed. It was also observed that, provided the moisture content of the board was in the critical range, most of the collapse recovery was achieved in the time it took to get the core of the board up to the steaming temperature of close to 100°C. This suggests that for most thicknesses a conservative reconditioning period of two hours at temperature is all that is required. This recommended shortening of the reconditioning cycle could dramatically increase the throughput of timber through the steam reconditioning chambers. Alternatively, it could mean that where modern final drying kilns are being used, the reconditioning treatment could be carried out within the final drying kiln. A finite element model was developed to demonstrate the mechanism by which collapse recovery occurs. The theory tested was that the elastic component that stores the energy to restore the shape of the deformed cell is primarily found in the S1 and S3 layers. In contrast, the inelastic component is primarily found in the S2 layer. The model generated here provided limited support for this theory.

Thesis (M.S.)--Baylor University, 2007. / Includes bibliographical references (p. 40-41).

Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 168-186). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 168-186). Also available on the Internet.

Thesis--Helsinki. / At head of title: University of Helsinki Central Hospital, Surgical Clinic II. Bibliography: p. [128]-134.

Thesis (Ph. D.)--University of Chicago, Dept. of Physics, August 2002. / Includes bibliographical references (p. 31). Also available on the Internet.

In this dissertation, I examine the relationship between environmental conditions and human activity in the landscape of the Argive Plain of Greece after the collapse of the Bronze Age palatial system (1200–750 B.C.). I use evidence from four locales: the Petsas House and the Lower Town at Mycenae, to the immediate northwest and southwest of the citadel respectively; the settlement at Chania, three kilometers downstream; and the Northwest Town of Tiryns, in the lower reaches of the plain. I apply micromorphological analysis (the microscopic analysis of soils and sediments) integrated with analysis of grain-size and soil chemistry (assessed by X-Ray Fluorescence and Fourier Transform Infrared) in order to place depositional events within the context of settlement change at the end of the Bronze Age. The climate had been drying during the Late Bronze. An earthquake ca. 1200 B.C. is concurrent with the beginning of the final period of occupation on the edge of the plain around Mycenae. Some accumulation of sandy muds, destabilized sediments from the largely abandoned citadel, is observed at Petsas House as well as in the Lower Town where, additionally, remains were buried by two deposits of red muddy gravels from uncultivated mountain slopes. The gravels are separated by a brief period of stability (less than a century) marked by a weak soil formation, and reached final equilibrium in the Early to Middle Geometric period (900–760 B.C.). At the same time, three kilometers downstream, similar red muddy gravels resulted in the interruption of activity at the settlement of Chania. Meanwhile, at Tiryns, 30 cm of sandy muds, also destabilized by drier conditions, were deposited over decaying mudbrick, implying that the site was already abandoned before sedimentation occurred. The burial of both Mycenae and Tiryns demonstrates the instability in the Argive landscape and the complications of relating these changes to settlement. In the environs of Mycenae, the sudden deposition of muddy gravels certainly brought about the abandonment at Chania, and possibly also in the Lower Town; while at Tiryns abandonment preceded accumulation. This study demonstrates how intensive geoarchaeological study must be a component in properly situating sites in their particular landscapes.

O colapso traqueal é caracterizado por alterações tanto anatômicas como histológicas da cartilagem hialina dos anéis traqueais e do músculo traqueal dorsal, ocasionando colapso dinâmico da traqueia durante o ciclo respiratório. A etiologia do colapso de traqueia é desconhecida e provavelmente multifatorial. O esforço repetido das vias respiratórias causa inflamação crônica da mucosa traqueal, manifestando assim a tosse, que exacerba o processo inflamatório. O colapso de traqueia manifesta um sinal clínico importante chamado síndrome de angústia respiratória. Geralmente acomete cães de raça miniatura ou toy, sendo mais observado em cães de idade média, ou idosos. O procedimento traqueoscópico é considerado padrão ouro no diagnóstico para àqueles animais com alterações respiratórias, em especial nos casos de colapso traqueal. A intervenção cirúrgica objetiva estabilizar a cartilagem da traqueia e o músculo traqueal. O avanço da tecnologia possibilitou o desenvolvimento de próteses (stents) de materiais diversos. A finalidade do uso do stent é manter o suporte cartilaginoso, eventualmente perdido pela via aérea. Em função disso, o objetivo deste trabalho foi de descrever e avaliar a colocação de stents intraluminais autoexpansivos de nitinol (liga de titânioníquel), no interior do lúmen traqueal de cães com colapso de traqueia pela técnica de traqueoscopia, e também avaliar as complicações trans e pós-operatórias, com acompanhamento periódico dos pacientes. Foram incluídos neste trabalho sete cães, com peso corporal inferior a 5kg, com diagnóstico clínico, radiográfico e endoscópico de colapso traqueal cervicotorácico e intratorácico, atendidos no HCV-FAVET/UFRGS. Os critérios de inclusão avaliados foram: manifestação de dispneia e tosse, tratamento clínico sem remissão dos sinais e colapso de traqueia grau III ou IV. O procedimento foi realizado utilizando o método diagnóstico de traqueoscopia rígida, sem o auxílio de fluroscopia, para a colocação dos stents, na tentativa de corrigir o defeito traqueal destes animais. Foi realizada radiografia cervicotorácica em todos os cães, em duas posições em ângulo de 90º, para avaliação do posicionamento do stent e da correção do defeito traqueal logo após o procedimento. Este exame foi igualmente realizado, aos 15 dias e mensalmente, até término do período de avaliação, de sete meses. Os animais foram submetidos à traqueoscopia aos 50 dias e aos sete meses após a colocação do stent, para avaliar a presença de colapso em outra região traqueal e/ou de brônquios ocorrência de fraturas do stent em quatro cães e presença de tecido de granulação. Pelas avaliações radiográficas e traqueoscópicas não foi evidenciada ocorrência de migração do stent em nenhum cão, mas fratura em quatro deles. Foi observada presença de tecido de granulação excessivo em todos eles. Neste estudo, a técnica de colocação de stent intraluminal autoexpansivo de nitinol por meio de traqueoscopia sem o uso de fluroscopia é considerada efetiva, pois houve melhora na qualidade, mas não no aumento de expectativa de vida desses cães. / The tracheal collapse is a disease characterized by both anatomical and histological changes in the hialine cartilage of the tracheal rings and the dorsal muscle, causing dynamic collapse of the trachea during the respiratory cycle. The etiology of tracheal collapse is unknown and probably multifactorial. Repeated airway stress causes chronic inflammation of the tracheal mucosa, thus manifesting cough, which exacerbates the inflammatory process. The collapse of the trachea demonstrates a significant clinical sign called respiratory distress syndrome. Usually affects breeds miniature or toy, more observed in middle-age or elderly. The tracheoscopic procedure is considered the gold standard in diagnosis for those animals with respiratory changes, especially in cases of tracheal collapse. The surgery aims to stabilize the cartilage of the trachea and tracheal muscle. The advancement of technology has enabled the development of prostheses (stents) of various materials. The purpose of a stent to keep the cartilaginous support is eventually lost by air. As a result, the objective of this study was to describe and evaluate the placement of intraluminal autoexpansives nitinol stents (nickel-titanium alloy), inside the tracheal lumen of dogs with tracheal collapse by tracheoscopy technique and also evaluate complications trans and postoperative, with periodic patient monitoring. This work seven dogs whith body weight less than 5kg, with clinical, radiographic and endoscopic diagnosis of cervicalthoracic and intrathoracic tracheal collapse seen at HCV-FAVET/UFRGS were included. Inclusion criteria were: manifestation of dyspnea and cough, clinical treatment without remission of sings and collapsing trachea grade III or IV. The procedure was performed using the diagnostic method of rigid tracheoscopy, without the aid of fluoroscopy for the placement of stents in an attempt to correct the tracheal defect of these animals. Cervicalthoracic radiography was performed in all dogs, in two positions at 90 °, to evaluate the positioning of the stent and the fix tracheal defect after the procedure. This examination was also performed at 15 days and monthly until the end of the evaluation period of seven months. The animals underwent tracheoscopy at 50 days and at seven months after stent placement, to assess the presence of tracheal collapse in another and / or bronchi occurrence of stent fractures in four dogs and the presence of granulation tissue region. By radiographic and reviews tracheoscopycs was not evidence of stent migration occurred in any dog, but fracture in four of them. Presence of excessive granulation tissue was observed in all of them. In this study, the technique of placing intraluminal autoexpansive nitinol stenting through tracheoscopy without the use of fluoroscopy is considered effective because there was an improvement in quality, but not the increase in life expectancy of these dogs.

O colapso traqueal é caracterizado por alterações tanto anatômicas como histológicas da cartilagem hialina dos anéis traqueais e do músculo traqueal dorsal, ocasionando colapso dinâmico da traqueia durante o ciclo respiratório. A etiologia do colapso de traqueia é desconhecida e provavelmente multifatorial. O esforço repetido das vias respiratórias causa inflamação crônica da mucosa traqueal, manifestando assim a tosse, que exacerba o processo inflamatório. O colapso de traqueia manifesta um sinal clínico importante chamado síndrome de angústia respiratória. Geralmente acomete cães de raça miniatura ou toy, sendo mais observado em cães de idade média, ou idosos. O procedimento traqueoscópico é considerado padrão ouro no diagnóstico para àqueles animais com alterações respiratórias, em especial nos casos de colapso traqueal. A intervenção cirúrgica objetiva estabilizar a cartilagem da traqueia e o músculo traqueal. O avanço da tecnologia possibilitou o desenvolvimento de próteses (stents) de materiais diversos. A finalidade do uso do stent é manter o suporte cartilaginoso, eventualmente perdido pela via aérea. Em função disso, o objetivo deste trabalho foi de descrever e avaliar a colocação de stents intraluminais autoexpansivos de nitinol (liga de titânioníquel), no interior do lúmen traqueal de cães com colapso de traqueia pela técnica de traqueoscopia, e também avaliar as complicações trans e pós-operatórias, com acompanhamento periódico dos pacientes. Foram incluídos neste trabalho sete cães, com peso corporal inferior a 5kg, com diagnóstico clínico, radiográfico e endoscópico de colapso traqueal cervicotorácico e intratorácico, atendidos no HCV-FAVET/UFRGS. Os critérios de inclusão avaliados foram: manifestação de dispneia e tosse, tratamento clínico sem remissão dos sinais e colapso de traqueia grau III ou IV. O procedimento foi realizado utilizando o método diagnóstico de traqueoscopia rígida, sem o auxílio de fluroscopia, para a colocação dos stents, na tentativa de corrigir o defeito traqueal destes animais. Foi realizada radiografia cervicotorácica em todos os cães, em duas posições em ângulo de 90º, para avaliação do posicionamento do stent e da correção do defeito traqueal logo após o procedimento. Este exame foi igualmente realizado, aos 15 dias e mensalmente, até término do período de avaliação, de sete meses. Os animais foram submetidos à traqueoscopia aos 50 dias e aos sete meses após a colocação do stent, para avaliar a presença de colapso em outra região traqueal e/ou de brônquios ocorrência de fraturas do stent em quatro cães e presença de tecido de granulação. Pelas avaliações radiográficas e traqueoscópicas não foi evidenciada ocorrência de migração do stent em nenhum cão, mas fratura em quatro deles. Foi observada presença de tecido de granulação excessivo em todos eles. Neste estudo, a técnica de colocação de stent intraluminal autoexpansivo de nitinol por meio de traqueoscopia sem o uso de fluroscopia é considerada efetiva, pois houve melhora na qualidade, mas não no aumento de expectativa de vida desses cães. / The tracheal collapse is a disease characterized by both anatomical and histological changes in the hialine cartilage of the tracheal rings and the dorsal muscle, causing dynamic collapse of the trachea during the respiratory cycle. The etiology of tracheal collapse is unknown and probably multifactorial. Repeated airway stress causes chronic inflammation of the tracheal mucosa, thus manifesting cough, which exacerbates the inflammatory process. The collapse of the trachea demonstrates a significant clinical sign called respiratory distress syndrome. Usually affects breeds miniature or toy, more observed in middle-age or elderly. The tracheoscopic procedure is considered the gold standard in diagnosis for those animals with respiratory changes, especially in cases of tracheal collapse. The surgery aims to stabilize the cartilage of the trachea and tracheal muscle. The advancement of technology has enabled the development of prostheses (stents) of various materials. The purpose of a stent to keep the cartilaginous support is eventually lost by air. As a result, the objective of this study was to describe and evaluate the placement of intraluminal autoexpansives nitinol stents (nickel-titanium alloy), inside the tracheal lumen of dogs with tracheal collapse by tracheoscopy technique and also evaluate complications trans and postoperative, with periodic patient monitoring. This work seven dogs whith body weight less than 5kg, with clinical, radiographic and endoscopic diagnosis of cervicalthoracic and intrathoracic tracheal collapse seen at HCV-FAVET/UFRGS were included. Inclusion criteria were: manifestation of dyspnea and cough, clinical treatment without remission of sings and collapsing trachea grade III or IV. The procedure was performed using the diagnostic method of rigid tracheoscopy, without the aid of fluoroscopy for the placement of stents in an attempt to correct the tracheal defect of these animals. Cervicalthoracic radiography was performed in all dogs, in two positions at 90 °, to evaluate the positioning of the stent and the fix tracheal defect after the procedure. This examination was also performed at 15 days and monthly until the end of the evaluation period of seven months. The animals underwent tracheoscopy at 50 days and at seven months after stent placement, to assess the presence of tracheal collapse in another and / or bronchi occurrence of stent fractures in four dogs and the presence of granulation tissue region. By radiographic and reviews tracheoscopycs was not evidence of stent migration occurred in any dog, but fracture in four of them. Presence of excessive granulation tissue was observed in all of them. In this study, the technique of placing intraluminal autoexpansive nitinol stenting through tracheoscopy without the use of fluoroscopy is considered effective because there was an improvement in quality, but not the increase in life expectancy of these dogs.

O colapso traqueal é caracterizado por alterações tanto anatômicas como histológicas da cartilagem hialina dos anéis traqueais e do músculo traqueal dorsal, ocasionando colapso dinâmico da traqueia durante o ciclo respiratório. A etiologia do colapso de traqueia é desconhecida e provavelmente multifatorial. O esforço repetido das vias respiratórias causa inflamação crônica da mucosa traqueal, manifestando assim a tosse, que exacerba o processo inflamatório. O colapso de traqueia manifesta um sinal clínico importante chamado síndrome de angústia respiratória. Geralmente acomete cães de raça miniatura ou toy, sendo mais observado em cães de idade média, ou idosos. O procedimento traqueoscópico é considerado padrão ouro no diagnóstico para àqueles animais com alterações respiratórias, em especial nos casos de colapso traqueal. A intervenção cirúrgica objetiva estabilizar a cartilagem da traqueia e o músculo traqueal. O avanço da tecnologia possibilitou o desenvolvimento de próteses (stents) de materiais diversos. A finalidade do uso do stent é manter o suporte cartilaginoso, eventualmente perdido pela via aérea. Em função disso, o objetivo deste trabalho foi de descrever e avaliar a colocação de stents intraluminais autoexpansivos de nitinol (liga de titânioníquel), no interior do lúmen traqueal de cães com colapso de traqueia pela técnica de traqueoscopia, e também avaliar as complicações trans e pós-operatórias, com acompanhamento periódico dos pacientes. Foram incluídos neste trabalho sete cães, com peso corporal inferior a 5kg, com diagnóstico clínico, radiográfico e endoscópico de colapso traqueal cervicotorácico e intratorácico, atendidos no HCV-FAVET/UFRGS. Os critérios de inclusão avaliados foram: manifestação de dispneia e tosse, tratamento clínico sem remissão dos sinais e colapso de traqueia grau III ou IV. O procedimento foi realizado utilizando o método diagnóstico de traqueoscopia rígida, sem o auxílio de fluroscopia, para a colocação dos stents, na tentativa de corrigir o defeito traqueal destes animais. Foi realizada radiografia cervicotorácica em todos os cães, em duas posições em ângulo de 90º, para avaliação do posicionamento do stent e da correção do defeito traqueal logo após o procedimento. Este exame foi igualmente realizado, aos 15 dias e mensalmente, até término do período de avaliação, de sete meses. Os animais foram submetidos à traqueoscopia aos 50 dias e aos sete meses após a colocação do stent, para avaliar a presença de colapso em outra região traqueal e/ou de brônquios ocorrência de fraturas do stent em quatro cães e presença de tecido de granulação. Pelas avaliações radiográficas e traqueoscópicas não foi evidenciada ocorrência de migração do stent em nenhum cão, mas fratura em quatro deles. Foi observada presença de tecido de granulação excessivo em todos eles. Neste estudo, a técnica de colocação de stent intraluminal autoexpansivo de nitinol por meio de traqueoscopia sem o uso de fluroscopia é considerada efetiva, pois houve melhora na qualidade, mas não no aumento de expectativa de vida desses cães. / The tracheal collapse is a disease characterized by both anatomical and histological changes in the hialine cartilage of the tracheal rings and the dorsal muscle, causing dynamic collapse of the trachea during the respiratory cycle. The etiology of tracheal collapse is unknown and probably multifactorial. Repeated airway stress causes chronic inflammation of the tracheal mucosa, thus manifesting cough, which exacerbates the inflammatory process. The collapse of the trachea demonstrates a significant clinical sign called respiratory distress syndrome. Usually affects breeds miniature or toy, more observed in middle-age or elderly. The tracheoscopic procedure is considered the gold standard in diagnosis for those animals with respiratory changes, especially in cases of tracheal collapse. The surgery aims to stabilize the cartilage of the trachea and tracheal muscle. The advancement of technology has enabled the development of prostheses (stents) of various materials. The purpose of a stent to keep the cartilaginous support is eventually lost by air. As a result, the objective of this study was to describe and evaluate the placement of intraluminal autoexpansives nitinol stents (nickel-titanium alloy), inside the tracheal lumen of dogs with tracheal collapse by tracheoscopy technique and also evaluate complications trans and postoperative, with periodic patient monitoring. This work seven dogs whith body weight less than 5kg, with clinical, radiographic and endoscopic diagnosis of cervicalthoracic and intrathoracic tracheal collapse seen at HCV-FAVET/UFRGS were included. Inclusion criteria were: manifestation of dyspnea and cough, clinical treatment without remission of sings and collapsing trachea grade III or IV. The procedure was performed using the diagnostic method of rigid tracheoscopy, without the aid of fluoroscopy for the placement of stents in an attempt to correct the tracheal defect of these animals. Cervicalthoracic radiography was performed in all dogs, in two positions at 90 °, to evaluate the positioning of the stent and the fix tracheal defect after the procedure. This examination was also performed at 15 days and monthly until the end of the evaluation period of seven months. The animals underwent tracheoscopy at 50 days and at seven months after stent placement, to assess the presence of tracheal collapse in another and / or bronchi occurrence of stent fractures in four dogs and the presence of granulation tissue region. By radiographic and reviews tracheoscopycs was not evidence of stent migration occurred in any dog, but fracture in four of them. Presence of excessive granulation tissue was observed in all of them. In this study, the technique of placing intraluminal autoexpansive nitinol stenting through tracheoscopy without the use of fluoroscopy is considered effective because there was an improvement in quality, but not the increase in life expectancy of these dogs.