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1
Monson, Elizabeth Ida. "Simulations of Controlled Fires Using the One-Dimensional Turbulence Model with Application to Fire Spread in Wildland Fires." BYU ScholarsArchive, 2012. https://scholarsarchive.byu.edu/etd/3163.
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The mechanism of flame propagation in fuel beds of wildland fires is important to understand and quantify fire spread rates. Fires spread by radiative and convective heating and often require direct flame contact to achieve ignition. The flame interface in an advancing fire is unsteady and turbulent, making study of intermittent flames in complex fuels difficult. This thesis applies the one-dimensional turbulence (ODT) model to a study of flame propagation by simulating a lab-scale fire representative of the flame interface in a fuel bed and incorporating solid fuel particles into the ODT code. The ODT model is able to resolve individual flames (a unique property of this model) and provide realistic turbulent statistics. ODT solves diffusion-reaction equations on a line-of-sight that is advanced either in time or in one spatial direction (perpendicular to the line-of-sight). Turbulent advection is modeled through stochastic domain mapping processes. A vertical wall fire, in which ethylene fuel is slowly fed through a porous ceramic, is modeled to investigate an unsteady turbulent flame front in a controlled environment. Simulations of this configuration are performed using a spatial formulation of the ODT model, where the ODT line is perpendicular to the wall and is advanced up the wall. Simulations include radiation and soot effects and are compared to experimental temperature data taken over a range of fuel flow rates. Flame structure, velocities, and temperature statistics are reported. The ODT model is shown to capture the evolution of the flame and describe the intermittent properties at the flame edge, though temperature fluctuations are somewhat over predicted. A solid particle devolatilization model was included in the ODT code to study the convective heating of unburnt solid fuels through direct flame contact. Here the particles are treated as sweet gum hardwood and a single-reaction, first order decomposition model is used to simulate the devolatilization rates. Only preliminary results were presented for a simple case, but this extension of the ODT model presents new opportunities for future research.
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Shahbazian, Ashkan. "Simplified thermal and structural analysis methods for cold-formed thin-walled steel studs in wall panels exposed to fire from one side." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/simplified-thermal-and-structural-analysis-methods-for-coldformed-thinwalled-steel-studs-in-wall-panels-exposed-to-fire-from-one-side(6aec12ea-0d18-43a6-b594-0f7bc4adca1c).html.
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The advantages of cold-formed thin-walled steel studs are many and their applications in building constructions continue to grow. They are used as load-bearing members. An example is lightweight wall panel assemblies which consist of channel steel studs with gypsum plasterboard layers attached to the two flanges, often with interior insulation. At present, expensive fire tests or advanced numerical modelling methods are necessary in order to discover the fire resistance of such wall assemblies. For common practice this is not effective and a simplified method, suitable for use in daily design, is necessary. The aim of this research is to develop such simplified methods. The first main objective of this study is to develop a simple approach to calculate the temperature distributions in the steel section, in particular the temperatures on both the exposed and unexposed sides when the panel is exposed to fire exposure from one side. These two temperatures are the most influential factors in the fire resistance of this type of wall assembly. The proposed method calculates the average temperatures in the flanges of the steel section and assumes that the temperature in the web is linear. The proposed method is based on a simple heat balance analysis for a few nodes representing the key components of the wall panel. The thermal resistance of these nodes are obtained by the weighted average of thermal resistances in an effective width of the panel within which heat transfer in the panel width direction is assumed to occur. The proposed method has been extensively validated by comparison with numerical parametric studies. In order to calculate the ultimate capacity of steel studs, the traditional method is by using effective width. However, this method is now being questioned as it considers elements of section in isolation and does not consider interaction between the elements. In addition, this method is not appropriate to be extended to steel studs under fire conditions. The cross-section under fire conditions has non-uniform temperature distribution which results in the non-uniform distribution of mechanical properties. Using an effective width method to deal with this problem will require many assumptions whose accuracy is uncertain. Recently, the direct strength method (DSM) has been developed and its accuracy for ambient applications has been comprehensively validated. This method calculates cross-sectional plastic resistance and elastic critical loads for local, distortional and global buckling modes with the aid of simple computer programs. The elastic and plastic resistances are then combined to give the ultimate resistance of the structure using interaction equations. This method is suited to steel studs with non-uniform temperature distribution in the cross-section. The second main objective of this study is to extend the direct strength method for application to thin-walled steel studs having non-uniform elevated temperature distributions in the cross-section. It has been found that the DSM concept is applicable, but the interaction equations should be modified to allow for the effects of elevated temperature (non-uniform temperature distribution and changes in stress-strain relationships). Also the effects of thermal bowing should be included when calculating the plastic resistance and the elastic buckling loads of the cross-section. This research has proposed new interaction equations and has developed design tools. By comparing the results of the proposed method with validated Finite Element simulations over a very large range of parametric studies, the proposed method has been demonstrated to be valid. The validation studies include both standard and parametric fire exposures and are generally applicable.
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Furniss, Brandon F. "Transformation of Form." Kent State University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=kent1240088310.
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Lehoťák, Roman. "Návrh betonové konstrukce s ohledem na požární odolnost." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2021. http://www.nusl.cz/ntk/nusl-444631.
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The diploma thesis deals with the analysis of internal forces and the design of the reinforcement of a reinforced concrete monolithic slab, a reinforcing wall and a column in the 1st floor of a dairy hall building. The fire resistance of selected structures was taken into account during dimensioning. The calculation of the internal forces was performed by the finite element method in Dlubal RFEM 5.24.
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Menegon, Julia. "Avaliação da suscetibilidade da alvenaria estrutural a danos por exposição a altas temperaturas com medidas de controle da dilatação." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/172027.
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A alvenaria estrutural é um dos mais antigos sistemas construtivos existentes. Atualmente estruturas em alvenaria encontram uma vasta aplicação em construções residenciais, sobretudo em obras de interesse social. No entanto, ao contrário das estruturas de concreto, cujo comportamento durante exposição ao fogo e sua resistência residual tem estudos e resultados amplamente disseminados, pouco se sabe a respeito do comportamento de estruturas de alvenaria submetidas à ocorrência de sinistros dessa natureza. Com a intensificação das preocupações acerca da segurança das edificações e de seus usuários em situações de incêndio, faz-se cada vez mais imprescindível o conhecimento do comportamento dos sistemas empregados atualmente na construção civil perante a ação de altas temperaturas. Tendo isso em vista, o presente trabalho teve por objetivo a realização de uma análise dos danos e do comportamento apresentados por amostras de alvenaria com função estrutural ao serem expostas ao aquecimento excessivo. Foram avaliadas nesse estudo paredes de pequenas dimensões executadas com blocos estruturais cerâmicos. Visando simular condições mais próximas da realidade, foram restringidas, com o auxílio de macacos hidráulicos, as laterais das amostras, para que houvesse contenção da dilatação das mesmas. Com o intuito de verificar diferentes tipologias de alvenarias, foram utilizados três blocos distintos: de 14 cm de largura, com resistências de 7 e 10 MPa, e de 19 cm de largura, com 7 MPa de resistência à compressão. Também foram variadas as espessuras das juntas entre as unidades e a argamassa de assentamento das mesmas, a fim de compreender a importância desses fatores para o comportamento das amostras, e, por fim, foram ensaiadas amostras com revestimento na face exposta As miniparedes foram acopladas a um forno de resistências elétricas e submetidas a um aquecimento próximo à curva padrão determinada por norma, até a temperatura máxima de 950ºC, a qual foi mantida pelo período de 4 horas. Foram mensurados, além da temperatura dentro do forno, no interior da parede e na superfície das amostras, os deslocamentos transversais ocorridos durante o ensaio. Também se utilizaram transdutores de deslocamento para verificar a dilatação dos blocos e o esmagamento ou abertura das juntas. Imagens termográficas da face oposta ao aquecimento foram capturadas no decorrer da exposição. Ao final das análises, pôde-se inferir que as miniparedes ensaiadas apresentaram bom desempenho frente à ação das altas temperaturas, mantendo sua estanqueidade, isolamento térmico e resistência mecânica. A restrição lateral não ocasionou desplacamentos dos blocos, no entanto, pôde-se observar transferência de tensão para os mesmos quando utilizadas nas juntas argamassas pouco flexíveis. O deslocamento transversal apresentado pelas amostras indicou deflexão em direção ao forno durante o aquecimento, com posterior reversão do sentido. Tal deflexão foi atenuada pela redução da espessura das juntas, pelo uso de argamassas menos flexíveis e pelo aumento da resistência e largura dos blocos. As alvenarias de 19 cm de largura e, especialmente, as dotadas de revestimento apresentaram melhor desempenho térmico que as demais.<br>Structural masonry is one of the oldest existing building systems. Nowadays, masonry structures find a wide application in residential constructions, mainly in those with social interest. However, unlike concrete structures, whose behavior during fire exposure and its residual resistance have widely disseminated studies and results, there is a lack of knowledge about the behavior of masonry structures submitted to fire. Because of the spread of concerns about the safety of buildings and their users in fire situations, it becomes essential to know the behavior of the systems currently used in civil construction when exposed to high temperatures. With this in view, the present study intended to analyze the damage and the behavior of structural masonry samples exposed to heating. This study evaluated clay hollow-bricks small walls, and, in order to simulate real conditions, the boundaries of the samples were restrained, with the aid of hydraulic jacks, aiming to restrain the deformation. In order to verify different types of masonry, three different blocks were used: 14 cm wide, with nominal strength of 7 and 10 MPa, and 19 cm wide, with 7 MPa of compressive strength. The thicknesses of the joints and the mortar were also varied, in order to understand the importance of these factors in the behavior of the samples, and, finally, samples were tested with a mono-layer coating at the exposed face. The small walls were coupled to an electrical furnace and subjected to a heating approximately equal to the standard curve, up to the maximum temperature of 950ºC, which was maintained for 4 hours The deflections of the samples during the test were measured, beyond the temperature inside the furnace, in the center of wall and at the non-exposed surface. Clip gages were also used to verify the expansion of the blocks and the crushing or opening of the mortar joints. Thermographic images of the opposite face were captured during the testing. At the end of this research, it was possible to affirm that the walls had good behavior against the high temperatures, maintaining their integrity, thermal insulation and load-bearing capacity. The restriction of the boundaries did not cause the spalling of the blocks, however, it was possible to observe the stress transfer to them in samples with rigid joint mortar. The deflection of the samples increases towards the furnace during the heating, and, then, they show the phenomenon of “reverse bowing”, changing the direction of the displacements. Reducing the thickness and increasing the stiffness of the joint mortars, as well as the increase in block strength and width attenuated such deflection. The masonry 19 cm width and, specially, the ones with coating shows better thermal performance, comparing to the others.
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Piskláková, Petra. "Požární stanice typu C1 ve Valašském Meziříčí." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2018. http://www.nusl.cz/ntk/nusl-372150.
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The diploma thesis deals with project documentation for the realization of a new fire station class C1 in Valašské Meziříčí. The building is is designet in two operating units - the garage part and the administrative part. The garage part has the necessary technical facilities and stockrooms. Over the garage there are rooms for firefighters performing the service during the night shift. The garage part follows the administrative part of the building, which has three above-ground floors. On the first floor there are offices of fire prevention, population protection and crisis management. On the second floor there are facilities for firefighters - a gym, a sauna, a day room and a classroom. The third above-ground floor is designed for the head of the territorial department, the chief of the fire station and the integrated rescue system office. The main entrance to the building is located in the administrative part of the western side at level 1NP. The structural system of the garage part consists of a prefabricated reinforced concrete frame. The administrative part is built in mansory system. The building is without cellar, roofed with flat roofs.
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Schwarzová, Veronika. "Požární stanice." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2017. http://www.nusl.cz/ntk/nusl-265460.
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Diploma thesis solves the creation of layout study and creation of documentation for the realization new fire station. It is an object amenities used to perform the fire protection services unit of the population of the professional fire category JPO I. The type of fire station is P2. The building layout consists of three interconnected buildings arranged in a U. Structurally the building is divided into two systems. The middle part of the building consists of reinforced concrete skeleton, which has two floors. On the ground floor is garage, on the second floor are located facilities for firefighters. The side buildings connected to the skeleton are build of ceramic bricks, it is a wall system. The main entrance to the building is in the south building at the level of the first floor, where is situated the administrative and operational part of building. This building has two floors. From the northern side, the technical background of the fire station and the workshop are connected to the middle part of the buildin The building is basementless and is roofed by flat roofs only. The object is located on the edge of the Kaplice town, the terrain is slightly sloping. The solved area contains a few related objects.
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Wojcik, Jindřich. "Hasičská stanice typu C2." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2017. http://www.nusl.cz/ntk/nusl-265507.
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Diplom thesis is about design of the fire station of type C2 for the HZS. The building is divided into two parts. First part of a building is designed as a rectangular recessed floor. The first part of building consists of two floors and one underground floor. Roofed by a single-layer flat roof of soft PVC. The building will be used to perform the services, the fire brigade. It will be used 24 hours a day. In the basement is located warehouse, HVAC room, utility room and a lounge with an alternative source of electricity. On the first floor are designed garages for storage technique and also the dressing room, workroom, washing box, warehouse, room for chemical-technical service and concierge. The second floor is designed to serve firefighters. The second part of the building is a training tower, which will be used to train firefighters and for drying hoses. The training tower is designed as a simple steel structure with four floors. The project was developed in the educational version of ArchiCAD 16th project is designed in accordance with the requirements of a layout, architectural design, structural design proper and safe use of the building.
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Bong, Felix Nyuk Poh. "Fire Spread on Exterior Walls." Thesis, University of Canterbury. Civil Engineering, 2000. http://hdl.handle.net/10092/8252.
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This report describes methods of predicting heat flux exposure to external walls due to the impingement of flame issuing through a window opening. A heat transfer model was set up for the purpose of predicting the geometry of the emerging flame and the resultant heat flux exposure to the wall surface.
An existing flame spread model implemented in the BRANZFIRE model was selected for characterising the flame spread on exterior wall cladding materials, as a function of the heat flux exposure (from the projecting flame to the wall) and the material flammability properties of the wall material. Modifications were made to the flame spread model. The result was a prediction of rate and extent of the upward flame spread as a function of time and the heat release rate of the burning cladding material.
It is concluded that the flame spread model has the potential to determine the flame spread characteristics associated with four different cladding materials. The flame spread model gave conservative prediction for three of the tested cladding materials.
Overall, the heat transfer model seems to predict the total heat flux density received by the exposing wall with reasonable accuracy. Further validation of the heat transfer model is needed before it can be successfully integrated into the flame spread model to provide a useful tool for characterising flame spread and estimating the heat flux exposure conditions.
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Brož, Matěj. "Požární stanice." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2017. http://www.nusl.cz/ntk/nusl-265667.
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The aim of my diploma thesis is a design of fire station. The object is designed to be fire station type C and it is for fire brigade. The object is designed in Czech Budweis. The building has two above ground floor. The structural system of building is wall system and reinfroced concrete frame. The roof is warm flat roof. The facade is ventilated with cladding and sandwich facade panel. Drawing part processed in a computer program ArchiCAD.
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Yang, Jin Rong. "The Application of Fuzzy Logic and Virtual Reality in the Study of Ancient Methods and Materials Used for the Construction of the Great Wall of China in Jinshanling." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu152410262072719.
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Valencia, Correa Andres. "Etude expérimentale des concentrations de suie et des vitesses dans une flamme de paroi verticale." Thesis, Normandie, 2017. http://www.theses.fr/2017NORMR059/document.
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La propagation d’un incendie dans un espace clos s’explique par l’inflammation de matières combustibles. Un cas important est celui de la propagation d’une flamme sur une paroi verticale. En effet si la flamme progresse dans le même sens que l’écoulement (cas co-courant), la croissance est rapide. Dans ce cas, l’émission des vapeurs combustibles (pyrolyse) et le dégagement de la chaleur apportée par la combustion sont couplés par les flux convectés et rayonnés à la paroi. Ces flammes de paroi verticale sont pilotées par les forces de flottabilité, et se caractérisent par un régime de basse vitesse et avec une forte production de suie. Bien que de nombreux travaux aient été consacrés à l’étude des flammes de paroi verticale [1-3], peu d’entre eux ont été dédiés à l’étude de l’écoulement dans la couche limite proche de la paroi et à l’étude des zones de production de suie, lesquels sont des données nécessaires pour la validation des codes de calcul. Pour cela, des mesures simultanées de vitesse par PIV et de concentration de suie par LII ont été réalisées sur un brûleur gaz en configuration paroi-verticale. Dans un premier temps, ces mesures ont permis l’analyse de la forme, de la taille et de la concentration des zones de formation de suies (poches de suie) à différentes hauteurs dans la flamme. Ensuite, les champs 2D de vitesses moyennes (horizontales et verticales) ont été étudiés, ainsi que leurs fluctuations (densités de probabilité et écart-type). Une description de la couche limite réactive, à l’aide d’une échelle caractéristique obtenue avec des mesures de vitesse plus résolues spatialement (PIV « zoomé »), a également été réalisée. Finalement, les mesures de LII et PIV couplées ont permis d’étudier l’influence du champ de vitesse sur la distribution des suies dans la flamme, ainsi que le transport et le flux turbulent de la fraction volumique de suie dans la couche limite réactive<br>The fire growth and spread on a confined space depends on the inflammation and combustion of combustible materials. An important case is the fire propagation on a vertical wall configuration, in which the pyrolysis gas and the total heat flux released by the flame are coupled by convective and radiative heat flux from the flame to the wall. This kind of flame is piloted by the buoyancy forces, and is characterized by a low velocity regime and a strong generation of soot particles. Although numerous works have been devoted on the study of vertical wall flames, few have been carried out on the analysis of the flame within the reactive boundary layer and the study of the zones of production of soot particles, which is data necessary for fire simulation codes validation. In this aim, simultaneous measurements of velocity by Particle Image Velocity (PIV) and of soot volume fraction by planar laser induced incandescence (LII) have been carried out on vertical wall fire generated by a vertical porous burner fed with a CH4/C2H4 mixture. First, the characteristics of soot sheet (shape, size, thickness, and peak concentration) have been studied at different heights into the flame, as well as the average and RMS soot volume fraction fields. Then, average and RMS fields of velocity and their probability density function have been analyzed. A description of the reactive boundary layer, through the definition of a characteristic velocity scale in the near-wall zone (viscous sub-layer), has been carried out by using a « PIV Zoom » set-up. Finally, simultaneous LII/PIV measurements have been carried out in order to study the influence of the aerodynamics of the flow on the soot volume fraction distribution, as well as the transport and turbulent flux of soot into the reactive boundary layer
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Tran, Hung. "Etude numérique et expérimentale du comportement au feu des éléments séparatifs en plaques de plâtre à ossature acier." Thesis, Cachan, Ecole normale supérieure, 2012. http://www.theses.fr/2012DENS0041.
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Les éléments séparatifs à base de plaques de plâtre (cloisons, bloc-porte…) sont d’abord destinés à délimiter les espaces à l’intérieur d’une construction. Ils contribuent aux exigences essentielles pesant sur l’ouvrage en termes de sécurité en cas d’incendie, d’isolation thermique et acoustique. La réglementation française stipule que la vérification de la résistance au feu des ces éléments doit être vérifiée par des essais en vraie grandeur menées selon des procédures normalisées et qui sont souvent onéreux pour les industriels. De plus, la limite du four (5 m de hauteur et 7 m de largeur actuellement) pose un problème pour les fabricants quand ils veulent valider des cloisons plus grandes. Par conséquent, la tendance industrielle est de développer une méthode prédictive du comportement au feu des éléments séparatifs. Cette thèse présente une étude dans le cadre du projet de recherche de EFECTIS France, ce qui conduit à l'élaboration d'un modèle numérique capable de prédire le comportement thermo-mécanique des cloisons en plaques de plâtre se composant d’une ossature métallique vissée sur des parements en plaques de plâtre, quand elles sont soumises à une action thermique normalisée de EN 1363-1 sur une face. Dans cette étude, on présente d’abord des programmes d’essais qui permettent d’une part, d’identifier les propriétés thermo-physiques et thermo-mécaniques de plaques de plâtre cartonné, à température ambiante et à haute température, et d’autre part de caractériser la liaison cinématique de la fixation par vissage des parements en plaques de plâtre sur les montants acier de l’ossature interne, à température ambiante. En suite, on présente le développement des modèles thermique et mécanique avec le logiciel CAST3M en utilisant les paramètres mesurés lors des programmes d’essais sur les matériaux et les assemblages. Les modèles développés permettent de prendre en compte : (i) les phénomènes de transfert thermique par conduction, rayonnement et convection au travers d’une cloison - (ii) la chute du parement exposé de la cloison pendant l’essai - (iii) le comportement mécanique de la cloison elle-même, c'est-à-dire le comportement thermo-mécanique de ses éléments constitutifs (plaques de plâtre cartonné et montants métalliques) ainsi que celui des assemblages vissés des plaques de parements sur les montants d’ossature<br>The fire resistance of building elements (partition walls, door sets ...) by means of tests according to standard procedures is often expensive for manufacturers. In consequence, Efectis France is conducting a specific research project aiming to develop an efficient and economical tool in order to carry out the preliminary design of new products as well as their optimization and extend the application of experimental results to configurations different from those of the test (change of size, of component, of boundary conditions ...). This thesis presents a study in the scope of above research project, which led to the development of a numerical model capable of predicting the thermo-mechanical behavior of separating elements such as flexible partitions made with internal steel studs and plasterboard facings, when they are subjected to standard thermal action of EN 1363-1 on one side. This study is organized in three steps. The first one is an experimental investigation relative to the characterization of thermo-physical and of thermo-mechanical properties of plasterboards used in above mentioned partition walls. In the second step, a specific numerical model for the analysis of plasterboard partition fire behavior is developed. This model allows treating not only nonlinear heat transfer but also the nonlinear structural behavior of the partitions from thermal stresses taking into account the degradation of rigidities for the punctual screwing of plasterboards on the steel studs. In the third step, the prediction of the numerical model is compared with experimental results in terms of temperature and displacements of the partitions. The comparisons enable to show the validity of the numerical model to predict appropriately the fire behavior of plasterboard partitions
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Holbrook, Ellenore. "Quiet Politics: Opposition movements and policy stasis surrounding the United States' financial industry." Ohio University Honors Tutorial College / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ouhonors1492614098649269.
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Larsson, Per A. "Dimensional Stability of Paper : Influence of Fibre-Fibre Joints and Fibre Wall Oxidation." Licentiate thesis, KTH, Fiberteknologi, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4635.
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Papper är ett mycket mångsidigt material. Trots detta finns det ett flertal egenskaper som begränsar papperets användbarhet. Ett av de större problemen med cellulosa- och lignocellulosafibrer är att de sänker sin fria energi genom att sorbera vatten, och denna sorption förändrar papperets dimensioner. Detta fenomen kallas vanligtvis för bristfällig dimensionsstabilitet och uppträder i form av registerfel vid flerfärgstryck eller som krullning, buckling och vågiga papperskanter vid utskrift, kopiering och lagring, eller med en vidare definition som förkortad livslängd hos lådor på grund av mekanosorptivt kryp. Avsikten med denna avhandling har varit att studera och kvantifiera vilka egenskaper som styr, och hur de påverkar, den vatteninducerade dimensionsförändringen som sker hos ett fibernätverk, samt hur dess dimensionsstabilitet kan förbättras. Detta har studerats både genom att ändra fiberns fuktsorptionsegenskaper och genom att förändra adhesionen och kontaktgraden mellan fibrerna i fiber-fiberfogarna. Fogegenskaperna har också varierats genom att tillverka laboratorieark torkade under inspänning samt ark torkade fritt för att minimera mängden inbyggda spänningar i arket. Blekt kraftmassa har behandlats med polyelektrolytmultilager (PEM) för att förbättra adhesionen mellan fibrerna och för att öka kontaktgraden mellan fibrerna i fogen. Kontaktgraden har även minskats genom förhorning av fibrerna före arkformning. För de ark som fick torka fritt gav PEM-behandlingen en ökad hygroexpansionskoefficient, det vill säga dimensionsförändringen normaliserad mot förändringen i fuktinnehåll, vid samma förändring i relativ luftfuktighet medan förhorningen minskade hygroexpansionskoefficienten något. Om arken emellertid torkades under inspänning observerades ingen skillnad i hygroexpansionskoefficient mellan de olika fibermodifieringarna. Detta tolkades som ett resultat av en ökad kontaktzon och en större utbredning ut ur fogens plan, när arken torkades utan inspänning. En utbredning som medför att en större del av fiberns transversella expansion överförs som expansion i pappersplanet. Fibrernas fuktsorptionsegenskaper förändrades genom natriumperjodatoxidering av 1,4-glukanernas C2-C3-bindning. Detta skapade sannolikt tvärbindningar i fiberväggen som förbättrade fiberväggens tålighet både genom att låsa fibrillerna närmare varandra och genom att ta bort potentiella adsorptionssäten som annars är tillgängliga för vattenadsorption. Perjodatoxidationen minskar också fibrernas kristallinitet och således frigjorde oxidationen hydroxylgrupper där vattenmolekyler kan adsorbera. Detta innebar att oxidationen både minskade och ökade interaktionen mellan vatten och fibervägg, men dock på olika strukturell nivå. Tvärbindningarna visade sig också märkbart reducera sorptionshastigheten när arken utsattes för en förändrad luftfuktighet så länge de inte tidigare utsatts för relativa luftfuktigheter nära mättnad. Som ett resultat av den lägre förändringen i fuktinnehåll vid en förändring i luftfuktighet från 20 till 85 % RF minskade dimensionsförändringens amplitud för de tvärbundna arken upp till 30 %. Emellertid uppvisade de tvärbundna arken en högre hygroexpansionskoefficeint, vilket innebär att de blev mer känsliga för absoluta förändringar i fuktinnehåll.<br>Paper is a very versatile material. Nevertheless, there are several factors limiting its usefulness, and one of the major issues is that cellulosic and ligno-cellulosic fibres lower their free energy by sorbing water and this water changes the dimensions of the paper. This phenomenon is usually referred to as a lack of dimensional stability and is often evident as misregister during multicolour printing or curl, cockle and wavy edges during printing, copying and storage or, with a wider definition, also as a shortened life-time of boxes during storage due to mechano-sorptive creep. The work described in this thesis aims to study and quantify the importance of the different mechanisms causing water-induced dimensional changes in a fibre network and to investigate how to improve the dimensional stability of ligno-cellulosic materials. This has been done both by altering the fiber properties such as the moisture sorptivity and by changing the adhesion and degree of contact within the fibre-fibre joints. The properties of the fibre-fibre joints have been varied by drying laboratory sheets both under restraint and freely to minimise the generation of built-in stresses. Bleached kraft fibres were treated using the polyelectrolyte multilayer (PEM) technique to improve the adhesion between the fibres and to increase the molecular contact within the joints. In contrast, the degree of contact was impaired by hornifying the fibres before sheet preparation. For sheets allowed to dry freely, the PEM-treatment increased the hygroexpansion coefficient, i.e. the dimensional movement normalised with respect to the change in moisture content, when subjected to changes in relative humidity whereas the hornification process resulted in a slightly lowered hygroexpansion coefficient. However, when the sheets were dried under restraint, the different joint and fibre modifications led to no difference in hygroexpansion coefficient. This was interpreted as being a result of an increase in the total contact zone between the fibres when the sheets were dried under restraint, with a greater extension in the outof- plain direction of the joint resulting in a transfer of a larger part of the transverse swelling to the in-plane expansion. The sorptivity of the fibres was changed by oxidising the C2-C3 bond of the 1,4- glucans with periodate. This most likely created covalent cross-links in the fibre wall both improved the integrity of the fibre wall by locking adjacent fibril lamellae to each other and also removed possible sites for water sorption onto the cellulose surfaces. Periodate oxidation also led to a decrease in the crystallinity of the cellulose within the fibres, making more cellulose hydroxyl groups available for the adsorption of water molecules. This means that the oxidation both decreased and increased the interaction between the fibre wall and moisture but, on two different structural levels. The crosslinks significantly reduced the sorption rate when the papers was subjected to changes in relative humidity, as long as the fibres were not subjected to humidities close to saturation. The smaller change in moisture content when the relative humidity was changed between 20 and 85 % RH meant that the dimensional stability of the crosslinked sheets was increased. On the other hand, the hygroexpansion coefficient was increased in the case of papers made from fibres with the highest degree of oxidation, i.e. the sheets became more sensitive to absolute changes in moisture content.<br>QC 20101117
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Larsson, Per. "Dimensional Stability of Paper Influence of Fibre-Fibre Joints and Fibre Wall Oxidation." Licentiate thesis, KTH, Fibre and Polymer Technology, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4635.
Full textAbstract:
<p>Papper är ett mycket mångsidigt material. Trots detta finns det ett flertal egenskaper som begränsar papperets användbarhet. Ett av de större problemen med cellulosa- och lignocellulosafibrer är att de sänker sin fria energi genom att sorbera vatten, och denna sorption förändrar papperets dimensioner. Detta fenomen kallas vanligtvis för bristfällig dimensionsstabilitet och uppträder i form av registerfel vid flerfärgstryck eller som krullning, buckling och vågiga papperskanter vid utskrift, kopiering och lagring, eller med en vidare definition som förkortad livslängd hos lådor på grund av mekanosorptivt kryp.</p><p>Avsikten med denna avhandling har varit att studera och kvantifiera vilka egenskaper som styr, och hur de påverkar, den vatteninducerade dimensionsförändringen som sker hos ett fibernätverk, samt hur dess dimensionsstabilitet kan förbättras. Detta har studerats både genom att ändra fiberns fuktsorptionsegenskaper och genom att förändra adhesionen och kontaktgraden mellan fibrerna i fiber-fiberfogarna. Fogegenskaperna har också varierats genom att tillverka laboratorieark torkade under inspänning samt ark torkade fritt för att minimera mängden inbyggda spänningar i arket.</p><p>Blekt kraftmassa har behandlats med polyelektrolytmultilager (PEM) för att förbättra adhesionen mellan fibrerna och för att öka kontaktgraden mellan fibrerna i fogen. Kontaktgraden har även minskats genom förhorning av fibrerna före arkformning. För de ark som fick torka fritt gav PEM-behandlingen en ökad hygroexpansionskoefficient, det vill säga dimensionsförändringen normaliserad mot förändringen i fuktinnehåll, vid samma förändring i relativ luftfuktighet medan förhorningen minskade hygroexpansionskoefficienten något. Om arken emellertid torkades under inspänning observerades ingen skillnad i hygroexpansionskoefficient mellan de olika fibermodifieringarna. Detta tolkades som ett resultat av en ökad kontaktzon och en större utbredning ut ur fogens plan, när arken torkades utan inspänning. En utbredning som medför att en större del av fiberns transversella expansion överförs som expansion i pappersplanet.</p><p>Fibrernas fuktsorptionsegenskaper förändrades genom natriumperjodatoxidering av 1,4-glukanernas C2-C3-bindning. Detta skapade sannolikt tvärbindningar i fiberväggen som förbättrade fiberväggens tålighet både genom att låsa fibrillerna närmare varandra och genom att ta bort potentiella adsorptionssäten som annars är tillgängliga för vattenadsorption. Perjodatoxidationen minskar också fibrernas kristallinitet och således frigjorde oxidationen hydroxylgrupper där vattenmolekyler kan adsorbera. Detta innebar att oxidationen både minskade och ökade interaktionen mellan vatten och fibervägg, men dock på olika strukturell nivå. Tvärbindningarna visade sig också märkbart reducera sorptionshastigheten när arken utsattes för en förändrad luftfuktighet så länge de inte tidigare utsatts för relativa luftfuktigheter nära mättnad. Som ett resultat av den lägre förändringen i fuktinnehåll vid en förändring i luftfuktighet från 20 till 85 % RF minskade dimensionsförändringens amplitud för de tvärbundna arken upp till 30 %. Emellertid uppvisade de tvärbundna arken en högre hygroexpansionskoefficeint, vilket innebär att de blev mer känsliga för absoluta förändringar i fuktinnehåll.</p><br><p>Paper is a very versatile material. Nevertheless, there are several factors limiting its usefulness, and one of the major issues is that cellulosic and ligno-cellulosic fibres lower their free energy by sorbing water and this water changes the dimensions of the paper. This phenomenon is usually referred to as a lack of dimensional stability and is often evident as misregister during multicolour printing or curl, cockle and wavy edges during printing, copying and storage or, with a wider definition, also as a shortened life-time of boxes during storage due to mechano-sorptive creep.</p><p>The work described in this thesis aims to study and quantify the importance of the different mechanisms causing water-induced dimensional changes in a fibre network and to investigate how to improve the dimensional stability of ligno-cellulosic materials. This has been done both by altering the fiber properties such as the moisture sorptivity and by changing the adhesion and degree of contact within the fibre-fibre joints. The properties of the fibre-fibre joints have been varied by drying laboratory sheets both under restraint and freely to minimise the generation of built-in stresses.</p><p>Bleached kraft fibres were treated using the polyelectrolyte multilayer (PEM) technique to improve the adhesion between the fibres and to increase the molecular contact within the joints. In contrast, the degree of contact was impaired by hornifying the fibres before sheet preparation. For sheets allowed to dry freely, the PEM-treatment increased the hygroexpansion coefficient, i.e. the dimensional movement normalised with respect to the change in moisture content, when subjected to changes in relative humidity whereas the hornification process resulted in a slightly lowered hygroexpansion coefficient. However, when the sheets were dried under restraint, the different joint and fibre modifications led to no difference in hygroexpansion coefficient. This was interpreted as being a result of an increase in the total contact zone between the fibres when the sheets were dried under restraint, with a greater extension in the outof- plain direction of the joint resulting in a transfer of a larger part of the transverse swelling to the in-plane expansion.</p><p>The sorptivity of the fibres was changed by oxidising the C2-C3 bond of the 1,4- glucans with periodate. This most likely created covalent cross-links in the fibre wall both improved the integrity of the fibre wall by locking adjacent fibril lamellae to each other and also removed possible sites for water sorption onto the cellulose surfaces. Periodate oxidation also led to a decrease in the crystallinity of the cellulose within the fibres, making more cellulose hydroxyl groups available for the adsorption of water molecules. This means that the oxidation both decreased and increased the interaction between the fibre wall and moisture but, on two different structural levels. The crosslinks significantly reduced the sorption rate when the papers was subjected to changes in relative humidity, as long as the fibres were not subjected to humidities close to saturation. The smaller change in moisture content when the relative humidity was changed between 20 and 85 % RH meant that the dimensional stability of the crosslinked sheets was increased. On the other hand, the hygroexpansion coefficient was increased in the case of papers made from fibres with the highest degree of oxidation, i.e. the sheets became more sensitive to absolute changes in moisture content.</p>
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Carlsson, Allan. "Near wall fibre orientation in flowing suspensions." Doctoral thesis, KTH, Linné Flow Center, FLOW, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-9995.
Full textAbstract:
This thesis deals with fibre orientation in wall-bounded shear flows. The primary application in mind is papermaking. The study is mainly experimental,but is complemented with theoretical considerations.The main part of the thesis concerns the orientation of slowly settlingfibres in a wall-bounded viscous shear flow. This is a flow case not dealt withpreviously even at small Reynolds numbers. Experiments were conducted usingdilute suspensions with fibres having aspect ratios of rp ≈ 7 and 30. It is foundthat the wall effect on the orientation is small for distances from the wall wherethe fibre centre is located farther than half a fibre length from the wall. Farfrom the wall most fibres were oriented close to the flow direction. Closer tothe wall than half a fibre length the orientation distribution first shifted to bemore isotropic and in the very proximity of the wall the fibres were orientedclose to perpendicular to the flow direction, nearly aligned with the vorticityaxis. This was most evident for the shorter fibres with rp ≈ 7.Due to the density difference between the fibres and the fluid there is anincreased concentration near the wall. Still, a physical mechanism is requiredin order for a fibre initially oriented close to the flow direction at about half afibre length from the wall to change its orientation to aligned with the vorticityaxis once it has settled down to the wall. A slender body approach is usedin order to estimate the effect of wall reflection and repeated wall contacts onthe fibre rotation. It is found that the both a wall reflection, due to settlingtowards the wall, and contact between the fibre end and the wall are expectedto rotate the fibre closer to the vorticity axis. A qualitative agreement withthe experimental results is found in a numerical study based on the theoreticalestimation.In addition an experimental study on fibre orientation in the boundarylayers of a headbox is reported. The orientation distribution in planes parallelto the wall is studied. The distribution is found to be more anisotropic closerto the wall, i.e. the fibres tend to be oriented closer to the flow direction nearthe wall. This trend is observed sufficiently far upstream in the headbox.Farther downstream no significant change in the orientation distribution couldbe detected for different distances from the wall.<br>QC 20100706
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Marin, Carl. "A Hole in the Wall." VCU Scholars Compass, 2013. http://scholarscompass.vcu.edu/etd/3114.
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Alipour, Yousef. "Furnace Wall Corrosion in a Wood-fired Boiler." Doctoral thesis, KTH, Yt- och korrosionsvetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-175427.
Full textAbstract:
The use of renewable wood-based fuel has been increasing in the last few decades because it is said to be carbon neutral. However, wood-based fuel, and especially used wood (also known as recycled wood or waste wood), is more corrosive than virgin wood (forest fuel), because of higher amounts of chlorine and heavy metals. These elements increase the corrosion problems at the furnace walls where the oxygen level is low. Corrosion mechanisms are usually investigated at the superheaters where the temperature of the material and the oxygen level is higher than at the furnace walls. Much less work has been performed on furnace wall corrosion in wood or used wood fired boilers, which is the reason for this project. Tests are also mostly performed under simplified conditions in laboratories, making the results easier to interpret. In power plants the interpretation is more complicated. Difficulties in the study of corrosion processes are caused by several factors such as deposit composition, flue gas composition, boiler design, and combustion characteristics and so on. Therefore, the laboratory tests should be a complement to the field test ones. This doctoral project involved in-situ testing at the furnace wall of power boilers and may thus contribute to fill the gap. The base material for furnace walls is a low alloy steel, usually 16Mo3, and the tubes may be coated or uncoated. Therefore tests were performed both on 16Mo3 and more highly alloyed materials suitable for protective coatings. Different types of samples exposed in used-wood fired boilers were analysed by different techniques such as LOM (light optical microscopy), XRD (X-ray diffraction), SEM (scanning electron microscopy), EDS (energy dispersive spectroscopy), WDS (wavelength dispersive spectroscopy), FIB (focused ion beam) and GD-OES (glow discharge optical emission spectroscopy). The corrosion rate was measured. The environment was also thermodynamically modelled by TC (Thermo-Calc ®). The results showed that 16Mo3 in the furnace wall region is attacked by HCl, leading to the formation of iron chloride and a simultaneous oxidation of the iron chloride. The iron chloride layer appeared to reach a steady state thickness. Long term exposures showed that A 625 (nickel chromium alloy) and Kanthal APMT (iron-chromium-aluminium alloy) had the lowest corrosion rate (about 25-30% of the rate for 16Mo3), closely followed by 310S (stainless steel), making these alloys suitable for coating materials. It was found that the different alloys were attacked by different species, although they were exposed in the boiler at the same time in the same place. The dominant corrosion process in the A 625 samples seemed to be by a potassium-lead combination, while lead did not attack the APMT samples. Potassium attacked the alumina layer in the APMT samples, leading to the formation of a low-protective aluminate and chlorine was found to attack the base material. The results showed that stainless steels are attacked by both mechanisms (Cl- induced attack and K-Pb combination). Decreasing the temperature of the furnace walls of a waste wood fired boiler could decrease the corrosion rate of 16Mo3. However, this low corrosion rate corresponds to a low final steam pressure of the power plant, which in not beneficial for the electrical efficiency. The short term testing results showed that co-firing of sewage sludge with used wood can lead to a reduction in the deposition of K and Cl on the furnace wall during short term testing. This led to corrosion reduction of furnace wall materials and coatings. The alkali chlorides could react with the aluminosilicates in the sludge and be converted to alkali silicates. The chromia layer in A 625 and alumina in APMT were maintained with the addition of sludge.<br>Förnybara träbaserade bränslen har ökat i användning under de senaste decennierna, eftersom det är koldioxidneutrala. Emellertid är träbaserade bränslen, och i synnerhet använt trä (även känt som återvunnet trä, returträ eller träavfall), mer korrosivt än skogsbränsle, på grund av högre halter klor och tungmetaller. Dessa ökar korrosionsproblemen på eldstadsväggarna, särskilt på platser där syrehalten är låg. Korrosionsmekanismer undersöks vanligtvis på överhettare dvs. på områden där materialets temperatur och syrenivån är högre än vid eldstadsväggarna. Färre arbeten har utförts på eldstadskorrosion i returträ pannor, vilket är motiveringen till detta projekt. Normalt sätt så görs endast i laboratorietester där resultaten är lättare att tolka. I kraftverk är tolkningen mer komplicerad. Undersökningar av korrosionsprocesser försvåras av flera faktorer såsom panndesign, förbränningsegenskaper, rökgassammansättning, beläggningskemi och så vidare. Därför bör laboratorietester kompletteras med fältförsök. Detta doktorandprojekt kan således bidra till att fylla denna brist. Eldstadsväggarna är uppbyggda av flera rör som svetsas samman och de består vanligtvis av 16Mo3 stål. Rören kan vara belagda eller obelagda. Tester har därför genomförts på 16Mo3 samt på höglegerade material vilka är lämpliga som skyddande beläggningar. Olika typer av prov som exponerats i förbränningspannor av returträ analyserades med olika tekniker såsom SEM (svepelektronmikroskopi), EDS (energidispersiv spektroskopi), WDS (våglängd dispersiv spektroskopi), FIB (fokuserad jonstråle) LOM (ljusoptisk mikroskopi), XRD (röntgendiffraktion), och GD-OES (glimurladdning med optisk emissionsspektroskopi). Miljön samt korrosionsprocesser har modellerats termodynamiskt med mjukvaran TC (Termo-Calc®). Resultaten visade att 16Mo3 i eldstadsväggen angrips av väteklorid, vilket leder till bildning av järnklorid och en samtidig oxidation av järnkloriden. Järnkloridskiktet verkade nå ett stationärt tillstånd vad avser tjocklek. Sex veckors prov visade att A 625 (nickelkromlegering) och Kanthal APMT (järnkromaluminiumlegering) hade den lägsta korrosionshastigheten (ca 25-30% av korrosionshastigheten för 16Mo3), följt av 310S (rostfritt stål). Vi har funnit att de olika legeringarna angrips genom olika mekanismer, även om de var exponerade i pannan samtidigt på samma plats. Den dominerande korrosionsmekanismen för legeringen A 625 verkar i huvudsak bero på kalium och bly, medan bly inte attackerar Kanthal APMT. Kalium angriper aluminiumoxidskiktet på Kanthal APMT, vilket leder till bildning av icke-skyddande aluminat medan klor i sin tur attackerar basmaterialet. Resultaten visar att rostfritt stål attackeras genom klor-inducerad korrosion samt kalium och bly i kombination. Reducering av temperaturen kan minska korrosionshastigheten hos 16Mo3. Men denna lägre korrosionshastighet motsvarar ett lågt slutligt ångtryck hos kraftverket, vilket inte är fördelaktigt för elverkningsgraden. De kortare exponeringarna visade att samtidig förbränning av avloppsslam med returträ kan leda till minskad avsättning av kalium och klor i form av alkaliklorider på eldstadsväggarna. Detta ledde till korrosionsminskning av alla studerade material. Dessa alkaliklorider skulle kunna reagera med aluminiumsilikaterna från slammet och omvandlas till alkalisilikater. Detta verkar minska den alkali-inducerade korrosionen på A 625, APMT och 310S. Den aluminiumoxid som bildades på APMT och det kromoxidskikt som bildades på A 625 upprätthölls med tillsats av slam.<br><p>QC 20151015</p>
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Zápotočný, David. "Návrh betonové konstrukce s ohledem na požární odolnost." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2020. http://www.nusl.cz/ntk/nusl-409785.
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Diploma thesis deals with design of selected parts of reinforced concrete construction of a multi-storey building with respect of fire resistance. The proposed elements are reinforced concrete locally suported ceiling slab, selected column and wall. These structures are located in the storage hall on the 1st underground floor. Different variants of structural design are consulted and compared in this work. The calculation of internal forces is performed in the calculation software Scia Engineer 19.1. The thesis includes a structural design as well as drawings. The construction is designed according to ČSN EN standarts.
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Benians, Thomas Anthony Scott. "In situ analysis of cotton fibre cell wall polysaccharides." Thesis, University of Leeds, 2012. http://etheses.whiterose.ac.uk/5433/.
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The cotton fibre is one of the most economically important cells in the world. Each year, over 25 million tonnes are harvested and the industry is responsible for 300 million jobs world-wide, with revenues of over $120 billion in the USA alone. For such an important cell there is little known about its cell wall composition as well as the functional roles of these polysaccharides during fibre development. Although much work has already been done on the cotton fibre transcriptome, a study of cell wall composition during development and maturation is crucial in linking these data to further understand fibre differentiation. This research explored the developmental biology of the cotton fibre in relation to key polysaccharide structures and architectural properties in the context of cell wall development. This has been achieved by the development of methodologies for the detection and imaging of low level polysaccharide epitopes of the cotton fibre using molecular probes known as monoclonal antibodies (mABs) and carbohydrate-binding modules (CBMs), directed in-situ to these glycans. Key polysaccharide changes were observed during fibre development, maturity and processing. Upon maturity, pectic homogalacturonan and xyloglucan were readily detectable at the surface of fibres after removal of the waxy outer layer. Other polysaccharides including arabinan, xylan and mannan, as well as cell wall glycoproteins were detected after treatments that removed the pectin-rich primary cell wall layer. This research shows that cell wall probes are powerful and useful tools to study cotton fibres throughout development, maturity and processing in the context of cell wall biology, though these polysaccharide changes need to be explored one by one to establish structure-function relationships. With the upcoming sequencing of the G. hirsutum genome, cotton fibre research will be an exciting field and the work presented here will provide a base for future studies, with potential for the manipulation of key developmental polysaccharides to alter the final fibre properties. The ultimate goal of improving cotton fibre properties will have significant economic, ecological and societal impacts for decades to come.
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Wong, William Chiu-Kit. "CFD Flame Spread Model Validation: Multi-Component Data Set Framework." Digital WPI, 2012. https://digitalcommons.wpi.edu/etd-theses/918.
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"Review of the literature shows that the reported correlation between predictions and experimental data of flame spread vary greatly. The discrepancies displayed by the models are generally attributed to inaccurate input parameters, user effects, and inadequacy of the model. In most experiments, the metric to which the model is deemed accurate is based on the prediction of the heat release rate, but flame spread is a highly complex phenomenon that should not be simplified as such. Moreover, fire growth models are usually made up of distinctive groups of calculation on separate physical phenomena to predict processes that drive fire growth. Inaccuracies of any of these “sub-models” will impact the overall flame spread prediction, hence identifying the sources of error and sensitivity of the subroutines may aid in the development of more accurate models. Combating this issue required that the phenomenon of flame spread be decomposed into four components to be studied separately: turbulent fluid dynamics, flame temperature, flame heat transfer, and condensed phase pyrolysis. Under this framework, aspects of a CFD model may be validated individually and cohesively. However, a lack of comprehensive datasets in the literature hampered this process. Hence, three progressively more complex sets of experiments, from free plume fires to fires against an inert wall to combustible wall fires, were conducted in order to obtain a variety of measurements related to the four inter-related components of flame spread. Multiple permutations of the tests using different source fuels, burner size, and source fire heat release rate allowed a large amount of comparable data to be collected for validation of different fire configurations. FDS simulations using mostly default parameters were executed and compared against the experimental data, but found to be inaccurate. Parametric study of the FDS software shows that there are little definitive trends in the correlation between changes in the predicted quantities and the modeling parameters. This highlights the intricate relationships shared between the subroutines utilized by FDS for calculations related to the four components of flame spread. This reveals a need to examine the underlying calculation methods and source code utilized in FDS."
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Devillard, Estelle. "Fibre-degrading enzymes of ruminal protozoan Polyplastron multivesiculatum." Thesis, University of Aberdeen, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322473.
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Thomas, Geoffrey Charles. "Fire resistance of light timber framed walls and floors." Thesis, University of Canterbury. Civil Engineering, 1996. http://hdl.handle.net/10092/5877.
Full textAbstract:
The structural fire resistance of light timber frame walls and floors has traditionally been determined by using standard fire resistance tests to provide a Fire Resistance Rating (FRR). The required FRR was prescribed by building codes and had little relation to likely fire severity. More recently, simple formulae have been used to determine an appropriate FRR given the ventilation parameters of a compartment, the likely fuel load and to a lesser extent the thermal properties of the compartment boundaries.
The work described in this thesis determines the validity of these formulae for light timber frame walls and floors and other materials.
It is shown that, computer modelling can be used to determine the thermal and structural performance of light timber frame walls and floors exposed to fire. The COMPF-2 program can be used with modification to model compartment fires. The thermal behaviour of cavity walls and floors exposed to fire can be modelled accurately using the TASEF program. The structural behaviour of light timber frame walls and floors exposed to fire can be modelled using a general purpose finite element program, such as ABAQUS.
The temperature dependent thermal properties used in the thermal model and the temperature dependent mechanical properties used in the structural model may not be absolutely accurate values, but are effective values that are (modifications of known values within a reasonable range) determined in the calibration process.
A simple temperature based failure criterion has been devised for the structural response of light timber frame walls and floors exposed to fires.
This study shows that simple time equivalent formulae are not suitable for the prediction of such a complex and variable phenomenon as the response of structures to fire.
For accurate prediction of structural response under fire exposure, a more rigorous computer based analysis can be used to give much more reliable results than a simple time equivalent method.
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O'Gara, Martin. "Numerical modelling of masonry compartment walls in fire situations." Thesis, University of Ulster, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342400.
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Siem, Knut Vidar Løvøy. "Modelling fibre orientation of the left ventricular human heart wall." Thesis, Norwegian University of Science and Technology, Department of Computer and Information Science, 2007. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-8796.
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<p>The purpose of this thesis is to obtain and represent the orientation of the muscle fibres in the left ventricular wall of the human heart. The orientation of these fibres vary continuously through the wall. This report features an introduction to the human heart and medical imaging techniques. Attention is gradually drawn to concepts in computer science, and how they can help us get a “clearer picture” of the internals of, perhaps, the most important organ in the human body. A highly detailed Magnetic Resonance Imaging data set of the left ventricle cavity is used as a base for the analysis with 3-D morphological transformations. Also, a 3-D extension of the Hough transformation is developed. This does not seem to have been done before. An attempt is made to obtain the general trend of the trabeculae carneae, as it is believed that this is the orientation of the inner-most muscle fibres of the heart wall. Suggestions for further work include refinement of the proposed 3-D Hough transformation to yield lines that can be used as guides for parametric curves. Also a brief introduction to Diffusion Tensor Magnetic Resonance Imaging is given.</p>
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GEREN, REBECCA. "CALCULATING FIRE-RESISTANCE RATINGS OF CONCRETE MASONRY UNIT (CMU) WALLS." Thesis, The University of Arizona, 2016. http://hdl.handle.net/10150/618764.
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This paper serves as a statement accompanying a capstone project for a degree in
Information: Science and Technology. It details the work that went into creating the
web page dedicated to helping specifications and codes writers to calculate fire resistance
ratings of concrete masonry unit (CMU) walls. It briefly examines what a
CMU wall is and the calculations that are involved in calculating fire-resistance
ratings. The paper delves into how the site itself works, what the user can expect to
see when first accessing the page and how to follow the steps in order to get the
correct output. Without getting too technical, the paper also describes the four
programming languages that were involved with coding the web page and what
they handle in accordance with the page’s design and implementation. Finally, the
paper concludes with an appendix containing the URL that will lead the reader to
the web calculator and provides some practice problems that will allow the reader
to test the calculator’s abilities.
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Hernandez-Gomez, Mercedes Clara. "Cell walls and cotton fibre development." Thesis, University of Leeds, 2015. http://etheses.whiterose.ac.uk/11458/.
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Morris, Brian. "A model test methodology for the fire testing of compartment walls." Thesis, University of Ulster, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245800.
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Fisher, Emma C. "If You Walk Through the Garden." Ohio University Honors Tutorial College / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ouhonors1619191618330079.
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Weber, Patrick William. "Everybody Knows How to Paint Walls." The Ohio State University, 1999. http://rave.ohiolink.edu/etdc/view?acc_num=osu1394804963.
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Taylor, Luca F. "Intramural: Within Four Walls." Kent State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=kent1557366339698542.
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Karlsson, Sofie, and Agnes Geijersson. "Optimering av en ytterväggsprodukt : En undersökning av alternativa isoleringsmaterial." Thesis, Linnéuniversitetet, Institutionen för byggteknik (BY), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-76446.
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AquaVillas CasaBona väggsystem innehåller i dagsläget isoleringsmaterialet EPS, vilket har visat svagheter vid brand. Målet med denna studie var att föreslå ett alternativt isoleringsmaterial till EPS med hänsyn till brand, energianvändning och U-värde, samt energiåtgång och koldioxidutsläpp vid tillverkning. Syftet var att det föreslagna alternativa isoleringsmaterialet skall kunna användas av tillverkare i väggprodukter som ett alternativ till EPS. I denna studie undersöktes fyra olika isoleringsmaterial genom kritisk granskning av vetenskapliga artiklar och litteratur, samt genom fältstudie och beräkningar i energiberäkningsprogrammet VIP-energy. De isoleringsmaterial som undersöktes var expanderad polystyren, polyuretan, polyisocyanurat och stenull. Resultaten visade att EPS, PUR och PIR är avsevärt sämre ur brandsynpunkt än stenull. Vid tillverkning av de olika isoleringsmaterialen fick EPS bäst resultat när det gäller koldioxidutsläpp. För energiåtgång vid tillverkning fick EPS bäst resultat då isoleringsskiktet i det undersökta väggsystemet var 200 mm tjockt, men då utgångspunkten istället var att väggen skulle ha ett U-värde på 0,112 W/m2K, fick stenull bäst resultat i denna kategori. PUR och PIR fick sämst resultat gällande både energiåtgång och koldioxidutsläpp vid tillverkning. Stenull gav väggen den bästa energianvändningen men samtliga material klarade kraven i Boverkets Byggregler. Vid sammanvägning av samtliga undersökta egenskaper för de olika isoleringsmaterialen anses det mest lämpliga materialet för en vägg vara stenull.<br>The AquaVilla CasaBona wall system currently contains the insulation material EPS, which has shown weaknesses while exposed to fire. The aim for this study was to suggest an alternative insulation material to EPS regarding fire, energy use and U-vale as well as energy use and carbon dioxide emissions for manufacturing. The purpose was that the suggested alternative insulation material should be able to be used by manufacturers in wall products as an alternative to EPS. In this study, four different insulation materials were examined by critically reviewing scientific articles and literature, as well as field studies and calculations with the energy calculation program VIP-energy. The insulation materials investigated were expanded polystyrene, polyurethane, polyisocyanurate and rockwool. The findings showed that EPS, PUR and PIR were not nearly as good as rockwool regarding fire. When manufacturing the various insulation materials, EPS gives the best results in terms of carbon dioxide emissions. EPS gives the best results regarding energy use for manufacturing when the insulation layer in the investigated wall system was 200 mm thick, but when the wall was given a U-value of 0,112 W/m2K, rockwool got the best results in this category. PUR and PIR gave the worst results regarding both energy use and carbon dioxide emissions at manufacturing. Rockwool generated the best results regarding energy use, but all of the materials met the requirements from Boverkets Byggregler. When comparing all the investigated characteristics of the various insulation materials, the most suitable material for an external wall was considered to be rockwool.
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Hladký, Adam. "Hasičská stanice." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2017. http://www.nusl.cz/ntk/nusl-265360.
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This diploma thesis „Firehouse“ is processed in the form of design documentation for building construction. It´s a new building of firehouse, JPO IV category, P type, for firefighters of Správa železniční dopravní cesty. Object is composed from three parts - administrative and operational part, garage for fire vehicles and maintenance part. Main entrance and exits from the garages are situated on west. Administrative and operational part has two floors and it´s roofed by double-shell roofs. The garage and maintenance have one floor and they are roofed by single-shell roof. Structural system is partly masonry and partly reinforced concrete. Object is located in flat terrain in peripheral locality of the Přerov city.
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Channa, Gaya Siriwardhana Kahandawa Arachchilage. "Conversion of Furnace oil fired boiler to biomass(Gliricidia) fired (External/Internal) furnace boiler : NA." Thesis, KTH, Energiteknik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-37118.
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In the present era, with the prevailing competition, the cost of production plays a vital role. As the price of petroleum oils, especially diesel and furnace oil are growing at a steeper rate than solid fuel price, finding a substitute for furnace oil is one of the alternative available. Furnace oil used in boilers can be totally substitute by biomass with an equivalent ratio of 3.5:1 kg/liter on the basis of calorific value. This may results in saving of more than 60% of operating cost and would have attractive payback period of 6-8 months. Sri Lanka has large agriculture base and very common of having Gliricidia as an under-grow. The other biomass fuels such as paddy husk, saw dust, firewood are also available in large quantities around the country. Objective of this article is to study the conversion of presently running furnace oil fired boiler, which is located at Ambilipitiya paper factory,Sri Lanka to biomass fired external furnace boiler namely water-wall boiler, techno economical study of the project and commissioning. Further a case study, which was done previous to this study and running successfully, is described to show the viability of the conversion using the internal furnace method. This case study was done at a Textile factory namely Brandix Finishing, Siduwa, and Sri Lanka. The results will be reducing the operating cost of the boilers and reduction of green house gas emission. Opportunities for rural people to get extra income by farming Gliricidia, extra income from saw dust, paddy husk, and firewood are indirect benefits of the project. This report gives details of technical, environmental and commercial aspects of this unique opportunity. Supervised by: Dr.Primal Fernando, Senior Lecturer, University of Peradeniya<br>NA<br>NA
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Bjurhager, Ingela. "Mechanical behaviour of hardwoods : effects from cellular and cell wall structures." Licentiate thesis, KTH, Fibre and Polymer Technology, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4830.
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<p>Syftet med den här avhandlingen var att undersöka mekaniska egenskaper hos olika arter av lövträd, och koppla egenskaperna till cell- och cellväggsstrukturen i materialet. Arterna som omfattades av undersökningen var Europeisk asp (<i>Populus tremula</i>), hybridasp (<i>Populus tremula x Populus tremuloides</i>) och ek (<i>Quercus robur</i>). Arterna inom familjen<i> Populus</i>, inklusive den snabbväxande hybridaspen, har på senare tid kommit att användas inom ett stort antal projekt inom genforskningen. Det har i sin tur ökat behovet av noggrannare bestämning av mekaniska egenskaper hos dessa arter. Ek har sedan tusentals år tillbaka varit ett populärt konstruktionsmaterial; något som har resulterat i ett stort antal arkeologiska ekfynd. Konservering av dessa inkluderar ofta dimensionsstabilisering med hjälp av polyetylen-glykol (PEG); en kemikalie som man vet påverkar de mekaniska egenskaperna. I vilken utstäckning detta sker är däremot inte helt klarlagt. Studien på euoropeisk asp och hybridasp inkluderade utveckling av en ny metod för provning av små juvenila prov i grönt tillstånd. Töjningsmätningar gjordes med hjälp av digital speckelfotografering (DSP). Axiell dragstyvhet och draghållfasthet var av speciellt intresse. Sämre mekaniska egenskaper hos hybridaspen korrelerade med medelvärden på densitet, som var lägre för hybriden än för den Europeiska aspen.</p><p> Ek undersöktes i svällt tillstånd, där svällningen inducerades med hjälp av PEG (molekylvikt 600). Axiell dragstyvhet och draghållfasthet samt radiell tryckstyvhet och ytspänning undersöktes. Töjningsmätningar i axiell riktning gjordes med hjälp av videoextensiometer, medan töjning i radiell riktning gjordes med hjälp av DSP. Övrig karakterisering av materialet inkluderade scanning electron microscopy (SEM), röntgenmikrotomografi och wide angle X-ray scattering (WAXS) för bestämning av mikrofibrillvinkel. Axiell dragstyvhet och draghållfasthet påverkades bara marginellt av PEG-behandlingen. WAXS-mätningarna visade att mikrofibrillvinkeln i materialet var mycket liten. Därigenom blir de mekaniska egenskaperna i axiell riktning till stor del beroende av mikrofibrillerna, vilket samtidigt minimerar den mjukningseffekt som PEG-impregneringen har på cellväggsmatrisen. De mekaniska egenskaperna i radiell kompression påverkades däremot starkt negativt av impregneringen. Detta antogs bero på den försvagande och uppmjukande effekt som PEG:en har på de radiellt orienterade märgstrålarna i veden.</p><br><p>The aim of this work was to investigate the mechanical properties of different hardwood species and relate the properties to the structure at the cellular and cell wall level. The species examined were European aspen (<i>Populus tremula</i>), hybrid aspen (<i>Populus tremula x Populus</i> <i>tremuloides</i>) and European oak (<i>Quercus robur</i>). The <i>Populus</i> species, including the fast-growing hybrid aspen, are used in a large number of projects using transgene technology, which also has raised the demand for a more extensive determination of mechanical properties of the species. Oak have been a popular construction material for thousands of years, esulting in a vast number of archaeological findings. Preservation of these often includes dimensional stabilization by polyethylene glycol (PEG), an impregnation agent which affects the mechanical properties. To which extent is not properly investigated, however. The study on European and hybrid aspen included development of a method for tensile testing of small, juvenile specimens in the green condition, where strain was measured using the digital speckle photography (DSP) technique. Mechanical performance of the species in terms of longitudinal tensile stiffness and strength were of special interest. Inferior mechanical properties of hybrid aspen corresponded well to mean values of density, which were lower for the hybrid aspen compared to European aspen.</p><p> Oak was examined in the swollen state, where swelling was induced by PEG with molecular weight 600. Longitudinal tensile stiffness and strength as well as radial stiffness and yield strength in compression were compared. Longitudinal and radial strain was measured using video extensiometry and DSP, respectively. Additional characterization of the material included imaging from scanning electron microscopy (SEM), X-ray microtomography and determination of microfibril angle using wide angle X-ray scattering (WAXS). Tensile stiffness and strength in the axial direction were only slightly affected by PEG-impregnation. WAXS measurements showed that microfibril angles were close to zero which implicates that cell wall properties are strongly dependent on the microfibrils, and only marginally influenced by the plasticization effects from PEG on the lignin/hemicellulose matrix. In the radial direction, on the other hand, mechanical performance was strongly decreased by PEG-impregnation. This was believed to originate from softening of rays.</p>
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Hébert, Damien. "Etude de la combustion des matériaux solides, application à la sécurité incendie." Phd thesis, INSA de Rouen, 2012. http://tel.archives-ouvertes.fr/tel-00795236.
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Dans une thématique de sécurité incendie, la prédiction de la propagation d'une flamme le long d'une paroi verticale solide nécessite la quantification du rayonnement. L'objectif de la thèse est de quantifier et caractériser les suies d'une flamme de PMMA. La flamme stationnaire d'un brûleur gaz sera également étudiée. La méthode optique de LII, une fois calibrée (extinction), permet d'obtenir des champs 2D de la fraction volumique ainsi que le taux de combustion en fonction de la hauteur pour la flamme de PMMA. Ensuite, la morphologie des agrégats de suie est déterminée grâce à des clichés MET et des mesures de la distribution en taille. Les propriétés optiques sont obtenues avec des mesures in-situ et ex-situ (effet de la température) de l'extinction spectrale, couplées avec une mesure de la concentration massique pour remonter à la fonction d'indice. Cette base de données permettra la perspective de calculer le rayonnement des suies et de l'utiliser dans un modèle de propagation.
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Cavanaugh, Tracy A. "Through a painters eye: exploration in enameling: jewelry and wall panels." Thesis, Boston University, 1988. https://hdl.handle.net/2144/38015.
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Thesis (M.F.A.)--Boston University<br>PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you.<br>This publication is the discussion and examination of work produced for the degree of Masters of Fine Arts in enameling and metal work. The body of work created consists of enameled brooches and wall panels. The thesis paper documents the technical and aesthetic developments in painting and metals as they pertain to the thesis work, and discusses the landscape subjects which so strongly influence the images that I create.
The work produced for the thesis show is discussed in the manner in which it was conceived, as groupings; or as series. Methods of manipulating enamels for specific visual and textural results, various enamel finishes, and the use of enamel oxides are documented. Metal techniques employed as well as the framing method devised for the presentation of the wall panels are also documented.
References and key incluences are painters and artists working in metalsmithing and jewelry. In the painting field Narcisse Diaz, Charles-Francois Daubigny, Eduard Vuillard and George Inness are nineteenth century artists who greatly influenced my artistic development. In the metals field Charles Loloma, Georg Jensen and Rene Lalique are influences which established the foundations of my ideas and tastes in my jewelry . While at graduate school the work and teachings of enamelists Jamie Bennett and William Hellwig initiated the interests I developed for enameling.
The paper is essentially an indepth analysis of the way in which I perceive my work, what I want to communicate to the viewer, and how and why I create the kinds of objects that I do.<br>2031-01-01
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Simmons, Thomas J. "Characterisation of five GH16 glycanase and transglycanase activities and of their hemicellulosic substrates." Thesis, University of Edinburgh, 2014. http://hdl.handle.net/1842/11733.
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Plant primary cell walls are hydrated extracellular complexes composed largely of polysaccharides: cellulose, hemicellulose and pectin. Cell wall constituents and composition vary in cell-, environment-, and species-dependent manners. For example, within land plant hemicelluloses xyloglucan is ubiquitous while mixedlinkage (1→3),(1→4)-β-D-glucan (MLG) is found only in the Poales and Equisetum. Glycosyl hydrolase 16 (GH16) enzyme family members include numerous enzymes with pertinence to the understanding of the ‘lives’ of cell wall hemicelluloses. However, despite this, the details of the interactions between GH16 enzymes and their substrates have often not been elucidated. Likewise, the true preferences of many of these enzymes and the range of substrates which they can utilise remain to be fully explored. By providing a greater wealth of information for the correlation of enzyme structure with reaction catalysed, such an understanding would enable better predictions of the activities of novel enzymes. Crucially, this would also allow better identification of roles performed by these enzymes in planta as well as of the potential applications of these enzymes. This work sought to further our understanding of the interactions between GH16 enzymes and their substrates by the study of five activities exhibited by GH16 enzymes – xyloglucan endotransglucosylase (XET), xyloglucan endoglucanase/hydrolase (XEG/XEH), mixed-linkage glucan : xyloglucan endotransglucosylase (MXE), lichenase and cellulose : xyloglucan endotransglucosylase (CXE). All of the analysed activities act on xyloglucan and/or MLG. Of particular focus is the novel enzyme MXE from the evolutionarily isolated genus Equisetum (horsetail), which acts on both. Notable findings include: identification of MXE/CXE gene; determination of the substrate specificity of MXE; defining of the sites of attack of lichenase, XEG, XET and MXE; discovery of novel xyloglucan structures and discrepancies between the xyloglucan present in different barley organs.
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Bregulla, Julie. "Investigation into the fire and racking behaviour of structural sandwich panel walls : a methodology to assess load bearing sandwich panels in fire." Thesis, University of Surrey, 2003. http://epubs.surrey.ac.uk/807/.
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Khalil, Ahmed Amir Ghobarah Ahmed. "Rehabilitation of reinforced concrete structural walls using fibre composites /." *McMaster only, 2005.
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Fahlén, Jesper. "The cell wall ultrastructure of wood fibres : effects of the chemical pulp fibre line." Doctoral thesis, KTH, Fiber- och polymerteknik, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-129.
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Knowledge of the ultrastructural arrangement within wood fibres is important for understanding the mechanical properties of the fibres themselves, as well as for understanding and controlling the ultrastructural changes that occur during pulp processing. The object of this work was to explore the use of atomic force microscopy (AFM) in studies of the cell wall ultrastructure and to see how this structure is affected in the kraft pulp fibre line. This is done in order to eventually improve fibre properties for use in paper and other applications, such as composites. On the ultrastructural level of native spruce fibres (tracheids), it was found that cellulose fibril aggregates exist as agglomerates of individual cellulose microfibrils (with a width of 4 nm). Using AFM in combination with image processing, the average side length (assuming a square cross-section) for a cellulose fibril aggregate was found to be 15–16 nm although with a broad distribution. A concentric lamella structure (following the fibre curvature) within the secondary cell wall layer of native spruce fibres was confirmed. These concentric lamellae were formed of aligned cellulose fibril aggregates with a width of about 15 nm, i.e. of the order of a single cellulose fibril aggregate. It was further found that the cellulose fibril aggregates had a uniform size distribution across the fibre wall in the transverse direction. During the chemical processing of wood chips into kraft pulp fibres, a 25 % increase in cellulose fibril aggregate dimension was found, but no such cellulose fibril aggregate enlargement occurred during the low temperature delignification of wood into holocellulose fibres. The high temperature in the pulping process, over 100 ºC, was the most important factor for the cellulose fibril aggregate enlargement. Neither refining nor drying of kraft or holocellulose pulp changed the cellulose fibril aggregate dimensions. During kraft pulping, when lignin is removed, pores are formed in the fibre cell wall. These pores were uniformly distributed throughout the transverse direction of the wood cell wall. The lamellae consisting of both pores and matrix material (“pore and matrix lamella”) became wider and their numeral decreased after chemical pulping. In holocellulose pulp, no such changes were seen. Refining of kraft pulp increased the width of the pore and matrix lamellae in the outer parts of the fibre wall, but this was not seen in holocellulose. Upon drying of holocellulose, a small decrease in the width of the pore and matrix lamellae was seen, reflecting a probable hornification of the pulp. Refining of holocellulose pulp led to pore closure probably due to the enhanced mobility within the fibre wall. Enzymatic treatment using hemicellulases on xylan and glucomannan revealed that, during the hydrolysis of one type of hemicellulose, some of the other type was also dissolved, indicating that the two hemicelluloses were to some extent linked to each other in the structure. The enzymatic treatment also decreased the pore volume throughout the fibre wall in the transverse direction, indicating enzymatic accessibility to the entire fibre wall. The results presented in this thesis show that several changes in the fibre cell wall ultrastructure occur in the kraft pulp fibre line, although the effects of these ultrastructural changes on the fibre properties are not completely understood.<br>QC 20101012
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Fahlén, Jesper. "The cell wall ultrastructure of wood fibres : effects of the chemical pulp fibre line /." Stockholm : Fibre and Polymer technology, KTH, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-129.
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Bartholomew, Anthony J. "Phillip Wall: Studies in Field Imagery Utilizing Screen Printing and Low Relief Techniques." [Kent, Ohio] : Kent State University, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=kent1208975444.
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Bailey, Rosslyn. "The properties and applications of fibre-reinforced sand in geotechnical structures." Thesis, University of the West of Scotland, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.311780.
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Dogruoz, Mehmet Baris. "Experimental and Numerical Investigation of Turbulent Heat Transfer due to Rectangular Impinging Jets." Diss., Tucson, Arizona : University of Arizona, 2005. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu%5Fetd%5F1370%5F1%5Fm.pdf&type=application/pdf.
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Miller, Robert J. "Ecological factors shaping subtidal rock wall communities in the Gulf of Maine." View this thesis online, 2005. http://libraries.maine.edu/gateway/oroauth.asp?file=orono/etheses/37803141.pdf.
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Thesis (Ph.D.)--University of Massachusetts Boston, 2005.<br>Title from PDF title page. Available through UMI ProQuest Digital Dissertations. Includes bibliographical references (p. 82-102). Also issued in print.
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Miller, Sarah Nattier. "The Wal-Mart consequence the anti-Wal-Mart movement /." [Pensacola, Fla.] : University of West Florida, 2009. http://purl.fcla.edu/fcla/etd/WFE0000168.
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Thesis (Ed.D.)--University of West Florida, 2009.<br>Submitted to the Dept of Professional and Community Leadership. Title from title page of source document. Document formatted into pages; contains 176 pages. Includes bibliographical references.
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Issa, Johnny Samir. "Scaling of Convective Heat Transfer in Laminar and Turbulent Wall Jets With Effects of Freestream Flow and Forcing." Diss., Tucson, Arizona : University of Arizona, 2006. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu%5Fetd%5F1672%5F1%5Fm.pdf&type=application/pdf.
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Wijanto, Ludovikus Sugeng. "Seismic Assessment of Unreinforced Masonry Walls." Thesis, University of Canterbury. Civil and Natural Resources Engineering, 2007. http://hdl.handle.net/10092/1680.
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This thesis focuses on the seismic performance of unreinforced masonry wall perforated with
a door opening representing typical URM walls of many aged masonry buildings in
Indonesia. To obtain a test result that will be able to represent the local conditions, the
experiments have been conducted in the Research Institute for Human Settlements (RIHS)
laboratory in Bandung-Indonesia.
Two 75 % unreinforced masonry (URM) walls with a 1½-wythe of solid clay-brick were
constructed in Dutch bond configuration and tested until failure under quasi-static-reversed
cyclic loading. Both units were loaded vertically by constant loads representing gravity loads
on the URM wall’s tributary area. Both models were constructed using local materials and
local labours. Two features were taken into account. First, it accommodated the influence of
flanged wall and second, the URM wall was built on the stone foundation. The first URM
wall represent the plain existing URM building in Indonesia and second strengthened by
Kevlar fibre.
It was observed from the test results that the URM wall Unit-1 did not behave as a brittle
structure. It could dissipate energy without loss of strength and had a post-elastic behaviour in
terms of “overall displacement ductility” value of around 8 to 10. As predicted, the masonry
material was variable and non homogeneous which caused the hysteresis loop to be non
symmetrical between push and pull lateral load directions. It can be summarized that Kevlar
fibre strengthening technique is promising and with great ease of installation. Although
Kevlar material is more expensive when compared to other fabrics as long as it was applied at
the essential locations and in limited volumes, it can significantly increase the in-plane URM
wall capacity. With appropriate arrangements of Kevlar fibre, a practicing engineer will be
able to obtain a desired rocking mechanism in the masonry structure. Another advantage for
the architectural point of view, very thin Kevlar fibres do not reduce the architectural space.
Studies have also been undertaken to analyze the in-plane response of plain URM wall before
and after retrofiting using the current seismic standard and the Finite Element Method (FEM).