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Waldmonitoring unter besonderer Berücksichtigung der aus Stereoluftbildern abgeleiteten 3. DimensionSysavath, Vithoone 17 November 2003 (has links)
Results of the investigation has been presented to derive digital elevation models of forest areas for the determination of the parallax measuring accuracy from AATE (Adaptive Automatic Terrian Extraction) with the PCI software Geomatica. It has been used the informations from the threefold overlaps of aerial stereoscopic pairs. The parallax measuring errors on forest areas are three times larger than on the arable and pasturelands. It has been shown that the third dimension can be used for the derivative of crown of tree profiles and their roughness and the rates of timber growth can be derived with sufficiently high accuracy from the repeatability flying.
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Ausgewählte Eigenschaften des Sporopollenins der KieferBohne, Guido 27 February 2007 (has links)
Gegenstand der Arbeit sind Zusammenhänge zwischen physikochemischen Eigenschaften und Funktionen der Exine bei Ausbreitung, Bestäubung und Befruchtung. Dabei bewährte sich der Einsatz der 3-kammrigen Sporopolleninkapseln (Zentralkapsel und Sacci) in der Permeationschromatographie. Sowohl kinetisch bedingte chromatographische Dispersion kleiner Moleküle als auch Konzentrationsänderungen von Zuckern und Dextranmolekülen im Medium wurden zur Bestimmung von Permeabilitätskoeffizienten der Nexine genutzt. Die Wasserabsorptionskapazität von Exinefragmenten und die hydraulische Leitfähigkeit der Nexine wurden anhand von Konzentrationsänderungen ausgeschlossener Dextranmoleküle ermittelt. Das Tectum der saccalen Sexine ist eine Mikrofiltermembran mit scharfer Trenngrenze im Submikrometerbereich; daher werden an den Sacci nur Hydrokolloide mit Stokes''schen Radius über 100 nm (z.B. aus nativem Dextran) ausgeschlossen. Die Nexine ist eine nicht-ideale Umkehrosmose-Membran, die in Zucker- und Salzlösungen hohe Reflexionskoeffizienten zeigt; zusätzlich besitzt sie wenige große Poren, die den Austausch von Zuckern und selbst kleinen Polymermolekülen ermöglichen. Die hydraulische Leitfähigkeit der Nexine liegt im Größenbereich derjenigen von Plasmamembranen (0,39-0,48 µm s-1 MPa-1); die Ergebnisse zeigen, dass die Exine weder die Nährstoffaufnahme des Sporoplasten aus der lokulären Flüssigkeit noch dessen rasche Rehydratation in der Mikropyle behindert. Die Einfaltungen der distalen Nexine (oberhalb der Sacci) und die Omega-Faltung der Exine zwischen den Sacci (Leptom) bieten beim Quellvorgang Schutz vor zu schneller Flächenausdehnung der Plasmamembran. Der Corpus kann mit konzentrierten Elektrolytlösungen beladen werden. Beim anschließenden osmotischen Schwellen in Wasser reißt die Exine, und der Sporoplast wird mit anhaftender Intine ausgeschleudert. Wasser und andere polare Flüssigkeiten adhärieren stärker als hydrophobe Flüssigkeiten an Sporopollenin. Die Sporopolleninmatrix weist eine hohe Feststoffdichte auf, ist wenig quellfähig (0,18 mL g-1 TM) und deformationsstabil. Dies ermöglicht die Pulverbildung beim Trocknen. / Subject of this thesis are relationships between physicochemical properties and functions of the exine concerning propagation, pollination and fecundation. Here the application of the 3-chambered sporopollenin-microcapsules (central capsule and sacci) in permeation chromatography proved of value. Both the kinetically dependent dispersion of small molecules and changes in concentration of sugars and dextran molecules in the medium were analysed to determine permeability coefficients of the nexine. The water absorption capacity of exine fragments and the hydraulic conductance of the nexine were calculated by means of changes in concentrations of excluded dextran molecules. The tectum of the saccal sexine is a microfiltration membrane with a sharp cut off in the submicrometer range; thus hydrocolloids with Stokes´radii over 100 nm (e.g. from native dextran) are excluded from the sacci. The nexine is a non-ideal reverse osmosis membrane having high reflexion coefficients in sugar and salt solutions; in addition few large pores allow the exchange of sugars and even of small polymers. The hydraulic conductance of the nexine is in the range typically for plasmamembranes (0.39-0.48 µm s-1 MPa-1); the results indicate that the exine does neither obstruct the uptake of nutrients by the sporoplast from the locular fluid nor hinder the rapid rehydration in the micropyle. When rehydrating, the distal foldings of the nexine (above the sacci) and the omega-like folding of the exine between the sacci (leptom), provide protection for the plasmamembrane when its surface area has to increase too rapidly. The corpus can be loaded with a concentrated electrolyte solution. When subsequently transferred into water the exine rupture and the sporoplast along with the intact intine is ejected. Water and other polar liquids adhere stronger to sporopollenin than hydrophobic ones. The matrix of sporopollenin show a high density in its solid content, water absorption capacity is low (0.18 mL g-1 DM) and it is resistant to deformation. This enable the formation of powder while dehydrating.
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Extended impregnation kraft cooking of softwood : Effects on reject, yield, pulping uniformity, and physical propertiesKarlström, Katarina January 2009 (has links)
<p>Converting wood into paper is a complex process involving many different stages, one of which is pulping. Pulping involves liberating the wood fibres from each other, which can be done either chemically or mechanically. This thesis focuses on the most common chemical pulping method, the kraft cooking process, and especially on a recently developed improvement of the impregnation phase, which is the first part of a kraft cook.</p><p>Extended impregnation kraft cooking (EIC) technique is demonstrated to be an improvement of the kraft pulping process and provides a way to utilize softwood to a higher degree, at higher pulp yield. We demonstrate that it is possible to produce softwood (<em>Picea abies</em>) kraft pulp using a new cooking technique, resulting in a pulp that can be defibrated without inline refining at as high lignin content as 8% on wood, measured as kappa numbers above 90. Lignin is the wood constituent that holds the wood fibres together in the wood matrix. The new cooking technique uses the differences in reaction rate between the diffusion and consumption of hydroxide ions; it is used to ensure a homogenous impregnation of wood chips at lower impregnation temperatures and longer impregnation times than are generally used in the industry. The applied cooking temperatures are also substantially lower than those used in conventional kraft pulping systems, promoting uniform delignification. This results in a narrower kappa number distribution than in lab-cooked conventional kraft pulp.</p><p>High-kappa-number pulps were investigated for pulp sheet properties such as tensile strength, tensile stiffness, and compression strength. It was demonstrated that an EIC pulp of kappa number 95 has strength properties comparable to those of a conventional pulp of kappa number 82. Comparing the effects of starch multilayers on conventional and EIC pulps reveals similar effects. The use of the starch multilayer treatment increased the tensile index and decreased the tensile stiffness and short-span compression test (SCT) indices.</p><p>The EIC technique has also been used to produce a series of bleachable-grade pulps. The results indicate the possibility of increasing the lignin content of the pulp entering the oxygen delignification stage, since the reject content of gently defibered pulp is lower than 0.1% at kappa number 49.</p><p>In this thesis, we recommend that wood chips be impregnated for 2 h at 110 °C to neutralize acidic compounds in the wood and impregnate the chips with cooking chemicals, and that the ensuing cook be performed at 135–140 °C, depending on the target kappa number. We also recommend increasing the available amounts of cooking chemicals in the impregnation stage by using a higher liquor-to-wood ratio and keeping the alkali profile fairly high in the ensuing cook. This concept will reduce the amount of reject material, increase the pulping uniformity, and increase the selectivity towards lignin degradation in the kraft cook.</p> / <p>Omvandling av ved till papper är en komplicerad process som består av många olika steg där ett är massaframställningen (eng. <em>pulping</em>). Massaframställning medför att vedfibrerna frigörs från varandra på kemisk eller mekanisk väg. Denna avhandling fokuserar på den vanligaste kemiska metoden, sulfatkokning och speciellt den nyligen utvecklade förbättringen av impregnerings fasen, som är den första delen av ett sulfatkok. <em></em></p><p>Här visas att<em> Extended Impregnation kraft Cooking </em>(EIC) innebär en förbättring av sulfatkokningen och ett sätt att uppnå högre vedutnyttjande vid högre utbyte för barrved. Vi visar att det är möjligt att producera barrvedsmassa med en ny kokningsprincip som resulterar i en massa som är defibrerbar utan inline-raffinering vid så högt lignin innehåll som 8% (på ved), mätt som kappatal över 90. Lignin är den vedkomponent som håller ihop vedfibrerna i vedmatrisen. Kokningsprincipen utnyttjar skillnaderna i reaktionshastighet mellan diffusion och konsumtion av hydroxidjoner och nyttjas till att skapa en homogen impregnering av vedflisen vid lägre impregneringstemperatur och under längre tid än vad som vanligen används i industrin. De använda koktemperaturerna är också betydligt lägre än vid konventionell sulfatkokning vilket gynnar jämn delignifiering. Detta resulterar i en smalare kappatalsfördelning jämfört med laboratoriekokade konventionella massor.</p><p>Massor med höga kappatal undersöktes med avseende på egenskaper hos handark, såsom dragstyrka, dragstyvhet och kompressionsstyrka Det visades att handark från EIC massa vid kappatal 95 hade jämförbara styrkeegenskaper med konventionell massa vid kappatal 82. Vid jämförelse av effekten av stärkelse multilager på konventionella och EIC massor avslöjar liknande effekter. Användningen av stärkelsemultilager ökade dragindex och minskade dragstyvhets- och kompressions index (SCT, short-compression test).</p><p>Kokprincipen har även använts för att ta fram en serie blekbara massor. Resultaten visar på möjligheten att öka lignininnehållet i massan in till i syrgasdelignifierings-steget eftersom spetinnehållet för milt defibrerad massa var lägre än 0,1% vid kappatal 49.</p><p>I den här avhandlingen rekommenderar vi att vedflis impregneras i 2 timmar vid 110 °C för att neutralisera sura komponenter i veden och impregnera flisen med kokkemikalier, samt att utföra det efterföljande koket vid 135–140 °C beroende på önskat kappatal. Vi rekommenderar även att öka den tillgängliga mängden kokkemikalier i impregneringssteget genom att använda högre vätske-ved förhållande och att hålla alkali profilen relativt hög i det efterföljande koket. Detta koncept reducerar spetmängden, ger jämnare kokning och ökar selektiviteten för nedbrytning av lignin i sulfatkoket.</p>
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ANCHORAGE MECHANICS OF DIFFERENT TYPES OF ROOT SYSTEMSMickovski, Slobodan B. 11 October 2002 (has links) (PDF)
The research presented in this thesis investigated the functional morphology in root<br />systems in relation to their role in providing anchorage and stability for the plant. The<br />anchorage of different types of root systems was investigated as well as the influence of<br />several environmental factors on their development. The research presented in this study<br />was completed by carrying out a series of modelling, glasshouse and field experiments<br />using physical models and real plants.<br />Model experiments showed that solid shapes like bulbs are very well suited to resist<br />vertical upward forces, i.e. uprooting, and shed some light on the mechanism of<br />anchorage in bulbs. The results of this laboratory study showed that the concept of<br />optimal bulb shape for resisting uprooting is viable. Uprooting tests on real bulb plants<br />confirmed the theoretical predictions about it, and showed the importance of bulbs in<br />anchorage. This study also proved that the soil type is very important when considering<br />the anchorage of solid forms such as the bulbs.<br />A second model study showed that the simplest models of tap root-dominated root<br />systems increase their resistance to overturning with the third and second power of the<br />embedment depth in cohesionless and in cohesive soil respectively. Anchorage strength<br />of a root system dominated by a tap root will be maximised with minimum investment<br />in structural material if the rigid tap root is extended to the largest possible depth.<br />Glasshouse experiments investigated the effects of soil compaction and temperature,<br />two of the most important environmental factors, on the axial and lateral development<br />and growth of the root systems of two species of young pines. It was shown that the rate<br />of root axial development in both investigated species decreased with an increase in soil<br />compaction whereas the lateral proliferation of their roots systems was not significantly<br />affected by soil consistency. A temperature of around 15°C seemed to be optimal for the<br />root elongation rate since the increase in axial length of the roots of both species was<br />largest at this temperature.<br />The effect of mechanical stimulation as a factor in shaping the root systems of plants<br />was also investigated. Apart from the changes caused to the parts of the tree above<br />ground, unidirectional periodical flexing induced an increase in total root CSA and<br />larger biomass allocation to the roots parallel to the plane of flexing which, in turn,<br />resulted in a larger number of major lateral roots with larger CSA in the plane of<br />flexing.<br />Mechanical and morphological field studies on two Pinus species investigated the<br />anchorage of plate root systems and showed that lateral roots in older trees are not the<br />major source of root anchorage in either of the species; although in both species a<br />certain asymmetry in the distribution of major lateral root CSA was recorded, it was not<br />significantly correlated to the asymmetry in anchorage.
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Extended impregnation kraft cooking of softwood : Effects on reject, yield, pulping uniformity, and physical propertiesKarlström, Katarina January 2009 (has links)
Converting wood into paper is a complex process involving many different stages, one of which is pulping. Pulping involves liberating the wood fibres from each other, which can be done either chemically or mechanically. This thesis focuses on the most common chemical pulping method, the kraft cooking process, and especially on a recently developed improvement of the impregnation phase, which is the first part of a kraft cook. Extended impregnation kraft cooking (EIC) technique is demonstrated to be an improvement of the kraft pulping process and provides a way to utilize softwood to a higher degree, at higher pulp yield. We demonstrate that it is possible to produce softwood (Picea abies) kraft pulp using a new cooking technique, resulting in a pulp that can be defibrated without inline refining at as high lignin content as 8% on wood, measured as kappa numbers above 90. Lignin is the wood constituent that holds the wood fibres together in the wood matrix. The new cooking technique uses the differences in reaction rate between the diffusion and consumption of hydroxide ions; it is used to ensure a homogenous impregnation of wood chips at lower impregnation temperatures and longer impregnation times than are generally used in the industry. The applied cooking temperatures are also substantially lower than those used in conventional kraft pulping systems, promoting uniform delignification. This results in a narrower kappa number distribution than in lab-cooked conventional kraft pulp. High-kappa-number pulps were investigated for pulp sheet properties such as tensile strength, tensile stiffness, and compression strength. It was demonstrated that an EIC pulp of kappa number 95 has strength properties comparable to those of a conventional pulp of kappa number 82. Comparing the effects of starch multilayers on conventional and EIC pulps reveals similar effects. The use of the starch multilayer treatment increased the tensile index and decreased the tensile stiffness and short-span compression test (SCT) indices. The EIC technique has also been used to produce a series of bleachable-grade pulps. The results indicate the possibility of increasing the lignin content of the pulp entering the oxygen delignification stage, since the reject content of gently defibered pulp is lower than 0.1% at kappa number 49. In this thesis, we recommend that wood chips be impregnated for 2 h at 110 °C to neutralize acidic compounds in the wood and impregnate the chips with cooking chemicals, and that the ensuing cook be performed at 135–140 °C, depending on the target kappa number. We also recommend increasing the available amounts of cooking chemicals in the impregnation stage by using a higher liquor-to-wood ratio and keeping the alkali profile fairly high in the ensuing cook. This concept will reduce the amount of reject material, increase the pulping uniformity, and increase the selectivity towards lignin degradation in the kraft cook. / Omvandling av ved till papper är en komplicerad process som består av många olika steg där ett är massaframställningen (eng. pulping). Massaframställning medför att vedfibrerna frigörs från varandra på kemisk eller mekanisk väg. Denna avhandling fokuserar på den vanligaste kemiska metoden, sulfatkokning och speciellt den nyligen utvecklade förbättringen av impregnerings fasen, som är den första delen av ett sulfatkok. Här visas att Extended Impregnation kraft Cooking (EIC) innebär en förbättring av sulfatkokningen och ett sätt att uppnå högre vedutnyttjande vid högre utbyte för barrved. Vi visar att det är möjligt att producera barrvedsmassa med en ny kokningsprincip som resulterar i en massa som är defibrerbar utan inline-raffinering vid så högt lignin innehåll som 8% (på ved), mätt som kappatal över 90. Lignin är den vedkomponent som håller ihop vedfibrerna i vedmatrisen. Kokningsprincipen utnyttjar skillnaderna i reaktionshastighet mellan diffusion och konsumtion av hydroxidjoner och nyttjas till att skapa en homogen impregnering av vedflisen vid lägre impregneringstemperatur och under längre tid än vad som vanligen används i industrin. De använda koktemperaturerna är också betydligt lägre än vid konventionell sulfatkokning vilket gynnar jämn delignifiering. Detta resulterar i en smalare kappatalsfördelning jämfört med laboratoriekokade konventionella massor. Massor med höga kappatal undersöktes med avseende på egenskaper hos handark, såsom dragstyrka, dragstyvhet och kompressionsstyrka Det visades att handark från EIC massa vid kappatal 95 hade jämförbara styrkeegenskaper med konventionell massa vid kappatal 82. Vid jämförelse av effekten av stärkelse multilager på konventionella och EIC massor avslöjar liknande effekter. Användningen av stärkelsemultilager ökade dragindex och minskade dragstyvhets- och kompressions index (SCT, short-compression test). Kokprincipen har även använts för att ta fram en serie blekbara massor. Resultaten visar på möjligheten att öka lignininnehållet i massan in till i syrgasdelignifierings-steget eftersom spetinnehållet för milt defibrerad massa var lägre än 0,1% vid kappatal 49. I den här avhandlingen rekommenderar vi att vedflis impregneras i 2 timmar vid 110 °C för att neutralisera sura komponenter i veden och impregnera flisen med kokkemikalier, samt att utföra det efterföljande koket vid 135–140 °C beroende på önskat kappatal. Vi rekommenderar även att öka den tillgängliga mängden kokkemikalier i impregneringssteget genom att använda högre vätske-ved förhållande och att hålla alkali profilen relativt hög i det efterföljande koket. Detta koncept reducerar spetmängden, ger jämnare kokning och ökar selektiviteten för nedbrytning av lignin i sulfatkoket. / QC 20120216
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