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Cao, Shuyun [Verfasser], Bernd [Akademischer Betreuer] Leiss, Bent T. [Akademischer Betreuer] Hansen, and Franz [Akademischer Betreuer] Neubauer. "Cenozoic tectonic deformation, thermochronology and exhumation of the Diancang Shan metamorphic massif along Ailao Shan-Red River shear zone, southeastern Tibet, China / Shuyun Cao. Gutachter: Bent T. Hansen ; Bernd Leiss ; Franz Neubauer. Betreuer: Bernd Leiss." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2011. http://d-nb.info/1042264902/34.
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Su, Yan. "An annular fluidized-bed experiment for inter-granular shear stress." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0008/MQ31257.pdf.
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Yeganeh-Bakhtiary, Abbas. "Computational mechanics of bed-load transport at high bottom shear." Kyoto University, 1999. http://hdl.handle.net/2433/181776.
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Chan, Ei Leen. "High shear granulation : a study of blade-granule bed interactions." Thesis, University of Sheffield, 2012. http://etheses.whiterose.ac.uk/3205/.
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Wet granulation, a common unit operation in multiple industries, involves the production of "granules" which are assemblies of primary particles held together by interparticle bonds. Depending on the application, granules with the required attributes such as enhanced strength, flowability, dissolution properties or uniform composition, can be manufactured. It is widely accepted in granulation research that the wet granulation process is comprised of several competing rate processes that dictate the granule growth behaviour and ultimately the granule attributes. In the micro-scale models developed for these rate processes (granule coalescence, consolidation and breakage) and further mapping studies to link formulation, processing and equipment variables to the granule growth behaviour, where the most significant of such work being the "Granulation growth regime map" (Iveson and Litster, 1998b; Iveson et al., 2001b), a fundamental parameter is the external stress exerted on the granules during granulation. The external stress is exerted by the main agitator in the granulator and subsequently transmitted via inter-granule or granule-wall collisions in the system. This thesis studies and characterises the external stress in a high shear granulator, more specifically the impeller blade-granule bed stress. The reserach was divided into the following main parts: A novel, custom-built telemetric impeller stress sensor in the studied granulator was first developed for direct measurements of the instantaneous blade-bed stress. With this system, the steady-state blade-bed stresses were studied for a range of parameters including bed load, granule sieve size and granule/particle density for dry beds and liquid addition for wet beds. The bed surface velocity, measured using high speed recording and analysed with Particle Imaging Velocimetry (PIV), was used to represent the characteristic velocity of the dynamic bed. A correction factor was applied to the theoretical blade-bed stress equation derived based on the imparted inertial stress on continuous bed, which accounted for the increasing bed 'fluidisation' with increasing impeller speed. This enabled much improved predictions of the time-averaged blade-bed stress for the studied parameters, especially at high impeller speeds. The blade-bed stress behaviour during the granulation process was also studied while looking at the evolution of granule attributes. Further characterisation of the steady-state blade-bed stress was carried out by simulating the dynamic dry particle beds in the high shear granulator using the Discrete Element Method (DEM), a widely used simulation method for granular systems. Following the validation of the DEM simulation with the experiments, additional impeller speeds, particle/particle bed properties, impeller geometries and granulator scales were studied from the simulations. A modified correction factor was also applied in the blade-bed stress equation to account for different granulator scales and blade widths. Additionally for the bed characteristic velocity, it was also shown that the bed surface velocity is not the dominant factor for the stress over-prediction from theory with increasing impeller speeds, i.e. the increasing bed 'fluidisation' is the dominant factor. Finally, the temporal values of the steady-state blade-bed stress, bed surface velocity and bed height were studied in terms of the variability/fluctuations, for the different parameters/conditions studied in the experiments and simulations as previously mentioned. More importantly, the results were also related to the identified flow regimes of the granule/particle bed when the impeller speed or Froude number was varied.
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Yaeger, Mary A. "MEAN FLOW AND TURBULENCE AROUND TWO SERIES OF EXPERIMENTAL DIKES." Thesis, The University of Arizona, 2009. http://hdl.handle.net/10150/193453.
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Scour around various structures obstructing flow in an open channel is a common problem; therefore a better understanding of how turbulent flow affects sediment transport is needed. Additionally, is it the mean flow or the turbulence properties that are more important in contributing to bed shear stress? To this end, an experimental study was conducted in a fixed-bed flume containing a series of dikes. Turbulence intensities and Reynold's stresses were calculated from 3-D velocity measurements gathered with a microADV. Results showed that the maximum shear stress was nearly 12-20 times that of the approach flow, while maximum turbulence intensities were about 3-5 times those of the incoming flow. Highest magnitudes of both were seen at the tip of the second dike in the three-dike series. The mean velocity appeared to have no relation to the formation of scour near the tips of the dikes but the turbulence intensities did.
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Sarra, Angela M. "Particle-wall shear stress measurements within the standpipe of a circulating fluidized bed." Morgantown, W. Va. : [West Virginia University Libraries], 2001. http://etd.wvu.edu/templates/showETD.cfm?recnum=2078.
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Thesis (M.S.)--West Virginia University, 2001.Title from document title page. Document formatted into pages; contains xi, 137 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 136-137).
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Yang, Qingjun (Judy Qingjun). "Estimation of the bed shear stress in vegetated and bare channels." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/99580.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, 2015.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 69-77).
The shear stress at the bed of a channel influences important benthic processes such as sediment transport. Several methods exist to estimate the bed shear stress in bare channels without vegetation, but most of these are not appropriate for vegetated channels due to the impact of vegetation on the velocity profile and turbulence production. This study proposes a new model to estimate the bed shear stress in both vegetated and bare channels with smooth beds. The model, which is supported by measurements, indicates that for both bare and vegetated channels with smooth beds, within a viscous sub-layer at the bed, the viscous stress decreases linearly with increasing distance from the bed, resulting in a parabolic velocity profile at the bed. For bare channels, the model describes the velocity profile in the overlap region of the Law of the Wall. For emergent canopies of sufficient density (frontal area per unit canopy volume a >/= 4.3m⁻¹ ), the thickness of the linear-stress layer is set by the stem diameter, leading to a simple estimate for bed shear stress.
by Qingjun (Judy) Yang.
S.M.
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Ying, Ker-Jen. "Lift on a sphere in shear flow near flat channel bed." Diss., Virginia Tech, 1991. http://hdl.handle.net/10919/39966.
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McGibbon, David. "Shear zones of the Maud Belt, Antarctica : kinetics and deformation mechanisms." Master's thesis, University of Cape Town, 2014. http://hdl.handle.net/11427/9607.
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Includes bibliographical references.The rocks of the Maud Belt, western Dronning Maud Land, Antarctica, have experienced at least two deformation phases related to the Grenvillian and Pan- African orogenies. Deformation is heterogeneous and strain is commonly localized within shear zones. The two study areas H.U. Sverdrupfjella and Neumayerskarvet mainly consist of paragneisses and orthogneisses and in places migmatites and granite intrusions. The orthogneisses and paragneisses mainly consist of coarse to medium grained quartz, feldspar and biotite and in places hornblende, garnet and epidote. The rock types only differ in the proportion of these minerals, the paragneisses having a higher proportion of biotite than the orthogneisses. Both study areas contain well developed lineations, defined by elongated quartz grains and in places hornblende and epidote, and a S₁+₂ foliation defined by biotite. The foliation is related to the shear zones in the region which are commonly sub-horizontal but locally sub-vertical in eastern Neumayerskarvet. In eastern Neumayerskarvet the paragneisses wrap around the competent orthogneiss units, resulting in sub-vertical strike-slip shear zones alongside the competent orthogniess units. Two differently orientated lineations are found in the study areas, a weak, shallow plunging, E-trending lineation that occurs within the host rock and always alongside a well developed, shallow plunging, SE-trending lineation. Within the shear zones only the SE-trending lineation is found. The presence of only the SE-trending lineation in the shear zones implies that the SE-trending lineation is associated with a more recent deformation phase, D₂, and that the weak Etrending lineation is associated with an older deformation phase, D₁. Two major collisional events affected the region, the Grenvillian (~1300 Ma to ~900 Ma) and the Pan-African (~600 Ma to ~450 Ma). D₂ is therefore likely associated with the Pan-African orogeny and D₁ with the older Grenvillian orogeny. Evidence for D₁ is distributed broadly within the host rock and is absent from the shear zones. If D₁ localized shear zones did exist, they have been overprinted by D₂. The presence of only D₂ in the shear zones implies that strain in D₂ was localized. The strain partitioning into narrow shear zones during the more recent deformation phase could be due to pre-existing fabrics from an earlier deformation phase. Superposition of later deformation into zones of pre-existing fabrics could be typical of areas that have experienced multiple deformation phases.
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Kottke, Peter Arthur. "Rheological Implications of Tension in Liquids." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/5015.
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This research investigates effects of tensile stresses in liquids. Areas of application include bearing lubrication and polymer processing, in which liquids may be subjected to hydrostatic tension or large shear stresses.
A primary thrust of this research is the development of a criterion for liquid failure, or cavitation, based upon the general state of stress in the liquid. A variable pressure, rotating inner cylinder, Couette viscometer has been designed and used to test a hypothesized cavitation criterion. The criterion, that cavitation will occur when a principal normal stress in a liquid becomes more tensile than some critical stress, is supported by the results of experiments with the viscometer for a Newtonian liquid. Based upon experimental observation of cavitation, a model for cavitation inception from crevice stabilized gas nuclei, and gaseous, as opposed to vaporous, cavitation is hypothesized.
The cavitation inception model is investigated through numerical simulation, primarily using the boundary element method. Only Newtonian liquids are modeled, and, for simulation purposes, the model is reduced to two dimensions and the limit of negligible inertia is considered. The model includes contact line dynamics. Mass transport of dissolved gas through the liquid and in or out of the gas nucleus is considered. The numerical simulations provide important information about the probable nature of cavitation nucleation sites as well as conditions for cavitation inception.
The cavitation criterion predicts cavitation in simple shear, which has implications for rheological measurements. It can cause apparent shear thinning and thixotropy. Additionally, there is evidence suggesting a possible link between shear cavitation and extrusion defects such as sharkskin. A variable pressure capillary tube viscometer was designed and constructed to investigate a hypothesized relationship between shear cavitation and extrusion defects. Results indicate that despite the occasional coincidence of occurrence of cavitation and sharkskin defects, cavitation cannot explain the onset of extrusion defects.
If nuclei are removed, then liquids can withstand a negative hydrostatic pressure. A falling body viscometer has been constructed and used to investigate the effect of negative pressures on viscosity. It is found that current pressure viscosity models can be accurately extrapolated to experimentally achievable negative pressures.
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Emerson, Samuel D. "The role of bed shear stress in sediment sorting patterns in a reconstructed, gravel bed river." Thesis, San Jose State University, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10128515.
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The role of bed shear stress in bed surface grain size sorting was investigated on a reconstructed reach of the Merced River in the Central Valley of California. Pebble count data were collected at the inside, middle, and outside of ten bends in April 2015 and compared to data from pebble counts conducted in previous years. Output from a previously developed 2D flow model (FaSTMECH) was compared to critical shear stresses calculated from median grain-size data. Comparison of pebble count results from 2002 through 2015 showed that there was no temporally consistent pattern of coarsening or fining along the study reach; however, the bed surface coarsened between 2002 and 2015. Pebble count data from April 2015 revealed a distinct spatial distribution of grain sizes with a larger median grain size (D50) at the outside of bends and a smaller D50 at the inside of bends. Regression analyses performed on pebble count data from point bars revealed statistically significant downstream changes in surface grain size on two of the seven bars. Analysis of shear stress data showed a weak relationship between the modeled bed shear stress (τb) and the calculated critical shear stress (τcr ). The weak relationship between τb and τcr indicated that bed shear stress was not solely responsible for the grain size sorting in the study reach. It is likely that the observed grain size sorting patterns resulted from helical secondary flows at the bends.
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Feltre, Gabriela. "Estudo das alterações na microestrutura de partículas de amido de milho em processos de granulação." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/74/74133/tde-14052015-092222/.
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O amido de milho é uma importante fonte de energia para os seres humanos e é muito utilizado em preparos de diversos pratos. Os grânulos de amido possuem estrutura semicristalina que sofre degradação em elevadas temperaturas e com presença de água. Com o objetivo de alterar a microestrutura dos grânulos de amido de milho, principalmente quanto à sua temperatura de gelatinização, foram realizados processos de aglomeração de três diferentes métodos e avaliadas as modificações ocorridas. Todas as partículas produzidas passaram por análises de DSC, FT-IR, DRX e MEV. O trabalho foi divido em três diferentes estudos. No Estudo I, foi realizada a aglomeração do amido de milho com solução de alginato de sódio por \"high shear\" com posterior secagem em leito fluidizado. A partícula depois de seca teve 99,5% de amido em sua composição. Os resultados mostraram que houve aglomeração nos grânulos de amido de milho; porém, devido à baixa fração de alginato de sódio nas partículas, elas não apresentaram diferenças significativas quanto à sua temperatura de gelatinização, sua estrutura e suas ligações, quando comparadas ao amido nativo. No Estudo II, em que foi realizada a aglomeração dos grânulos de amido de milho com solução de alginato de sódio e cloreto de cálcio, por \"dripping\", foram obtidas partículas com frações de (0, 50, 60, 70, 80 e 90)% de amido. As modificações aconteceram à medida em que se aumentou a quantidade de alginato de sódio da partícula. As partículas com maiores frações de amido não apresentaram alterações significativas em sua microestrutura e temperatura de gelatinização, quando comparadas ao amido de milho nativo. As partículas com menores frações de amido, ou seja, maiores teores de alginato de sódio, apresentaram alterações em sua microestrutura e cristalinidade, além de maiores temperaturas de gelatinização. No Estudo III, foi realizada a aglomeração do amido de milho com quitosana por \"dripping\" em soluções de diferentes molaridades de de hidróxido de sódio (NaOH). Dentre as principais modificações observadas, destaca-se o aumento da temperatura de gelatinização, em partículas que foram precipitadas em soluções alcalinas de NaOH com molaridade de (0,10 e 0,12) M. Para as concentrações molares de (0,14, 0,16, 0,18 e 0,20) M, de NaOH, observou-se que parte dos grânulos de amido de milho foram solubilizados pela solução alcalina, e que as frações sólidas remanescentes apresentaram-se na forma de partículas precipitadas de amido-quitosana, com aparência transparente e amarelada. Os processos de aglomeração do amido de milho nativo pelos métodos \"high shear\" e \"dripping\", utilizando-se soluções de alginato de sódio e quitosana, podem resultar em partículas resistentes à gelatinização, devido à atribuição de uma barreira física por estes ligantes, após as etapas de secagem. O aumento da concentração de alginato resultou em um aumento da temperatura de gelatinização, produzindo partículas de amido resistentes à degradação térmica. Adicionalmente, observou-se que o uso de soluções alcalinas diluídas de NaOH, também permitiu a produção de partículas resistentes à degradação térmica, por meio da precipitação da quitosana. O método \"dripping\" permitiu a produção de partículas com elevadas concentração de alginato ou quitosana, e foi o método mais indicado para a produção de partículas de amido resistentes à degradação térmica. As partículas aglomeradas pelo método \"high shear\" tiveram concentração de ligante (alginato de sódio) limitada a 0,5%, e não resultaram em partículas resistentes à degradação térmica.Corn Starch is an important source of energy for humans and is widely used in food preparations. Starch granules exhibit a semicrystalline structure which undergoes degradation at high temperatures and the presence of water. In order to change the microstructure in corn starch granules, especially regarding its gelatinization temperature, three diferente methods of agglomeration processes were performed and changes of starch particles were studied. Every produced particle were analysed by DSC, FT-IR, XRD and SEM. The work was divided into three different studies. In Study I, agglomeration of corn starch was carried out with sodium alginate solution by \"high shear\" with subsequent fluidized bed drying. The dry contained was 99,5% starch in its composition. The results showed that the cornstarch granules agglomerated; however, due to the low fraction of sodium alginate in the particles, they showed no significant differences in gelatinization temperature, its structure and interactions when compared to native starch. In Study II, was performed the agglomeration of corn starch granules with sodium alginate solution and calcium chloride by dripping method and particles obtained contained (0, 50, 60, 70, 80 and 90)% (w/w) of starch. Modifications occurred with increasing the amount of sodium alginate in the particle. Particles with higher starch fractions showed no significant changes in its microstructure and gelatinization temperature, compared to the native corn starch. Particles with lower starch fraction, and higher concentrations of sodium alginate, showed changes in their microstructure and crystallinity, and higher gelatinization temperatures. In Study III, the agglomeration of cornstarch with chitosan by dripping in sodium hydroxide (NaOH) solutions of different molarities was evaluated. Among the main changes increases on the gelatinization temperature of particles precipitated in alkaline NaOH solutions with molarity (0,10 and 0,12) M was observed. For the molar concentrations (0,14, 0,16, 0,18 and 0,20) M NaOH, it was observed that some of granules corn starch were solubilised by the alkaline solution and the remaining solid fraction presented the form of precipitated particles of starch-chitosan with transparent and yellowish appearance. The native corn starch agglomeration processes by the methods \"high shear\" and \"dripping\", using solutions of sodium alginate and chitosan, can result in particles resistant to gelatinization due to the formation of a physical barrier of these ligands, after drying steps. Increasing the alginate concentration resulted in increase in the gelatinization temperature of starch, resulting in particles resistant to thermal degradation. Additionally, it was observed that the use of dilute alkaline solutions of NaOH allowed the production of thermal degradation resistant particles through precipitation of chitosan. The \"dripping\" method enabled the production of particles with higher concentrations of alginate or chitosan, and was the most suitable method for the production of starch particles resistant to thermal degradation. The particles agglomerated by \"high shear\" had binder concentration (sodium alginate) limited to 0,5%, and didi not result in particles resistant to thermal degradation.
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Zhang, Hong Dong. "Shear lag in tube-in-tube structures coupled with outrigger and belt trusses." Thesis, University of Macau, 2003. http://umaclib3.umac.mo/record=b1636335.
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Perret, Emeline. "Transport of moderately sorted gravels at low bed shear stress : impact of bed arrangement and fine sediment infiltration." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSE1223/document.
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Le but de cette thèse est de comprendre la dynamique des graviers au sein des rivières alpines à faible contrainte en utilisant des expériences en laboratoire. Ces rivières sont souvent composées d’une large gamme de sédiments, allant des argiles aux galets. Ces différentes classes sédimentaires peuvent interagir entre elles, ce qui peut rendre difficile l’estimation du transport solide. Des expériences en laboratoire ont été conduites en écoulements instationnaires dans un canal de 18m de long et 1m de large. Deux types de lits ont été étudiés : lits unimodaux et bimodaux. Une attention particulière a été portée sur la réalisation des lits de graviers dans notre canal. Ils ont été créés dans le but d’approcher au mieux la configuration des lits de rivières alpines, c’est-à-dire avec différents arrangements et degrés de colmatage du lit par des sédiments fins. Les lits unimodaux sont composés de graviers peu triés avec divers arrangements de surface. Les lits bimodaux sont composés d’une matrice de graviers peu triés dans laquelle des sédiments fins se sont infiltrés (sables ou limons). Les processus régissant le transport de graviers ont été mis en avant. Le transport de graviers est impacté par l’arrangement du lit, la concentration de sédiments fins dans la couche de charriage, et par le changement de propriétés du lit due à la présence de sédiments fins (cohésion, perméabilité du lit). Plus le lit est arrangé, plus le transport est difficile. Plus la couche de charriage est concentrée en sédiments fins, plus le transport est facile. La forme des sédiments fins est aussi un facteur important pouvant modifier le transport des graviers. La présence de sédiments fins cohésifs dans la matrice peut considérablement réduire le taux de graviers transportés. Un modèle conceptuel a été développé pour résumer les différents processus contrôlant le transport de graviers. Il décrit le comportement des graviers dans les différentes configurations étudiées. L’outil proposé peut aider à comprendre, estimer et interpréter le transport de graviers. Il a été appliqué et discuté sur un cas de terrain sur la rivière de l’Arc. Basé sur ce modèle, nous avons proposé une nouvelle analyse dimensionnelle pour la construction d’un modèle de prédiction de transport solide prenant en compte des paramètres décrivant l’arrangement du lit, les propriétés géotechniques du lit et la présence de sédiments finsThis PhD thesis aims to understand gravel dynamics in Alpine rivers at low bed shear stress using laboratory experiments. Alpine river beds are often poorly sorted and composed of sediments ranging from clay to pebble. To understand interactions between these classes is an issue for predicting bedload rate. Laboratory experiments were performed in a 18m long and 1m wide flume, under unsteady flows. Two types of bed were investigated: unimodal and bimodal beds. A particular attention was paid to the bed construction, which was conducted in order to obtain a nature-like bed 12with different bed arrangements and degrees of clogging. Unimodal beds were made of moderately sorted gravels with different bed surface arrangements. Bimodal beds were made of moderately sorted gravels in which fine sediments (sand or silt) were infiltrated. Gravel rate was found to be impacted by the bed arrangement degree, the fine sediment concentration within the bedload layer and the changes in bed properties due to fine sediment presence (bed cohesion, bed permeability). The more packed the bed is; the more difficult it is to move gravels. The more concentrated in fine sediment the bedload layer is; the easier the transport of gravels is. The shape of fine sediments can also be an important factor for modifying the gravel rate. The presence of cohesive fine sediments within the bed matrix reduces significantly the gravel rate. A conceptual model was developed to recap the different processes controlling gravel transport. It provides a phenomenological description of the overall bed responses to a hydrograph. This tool is designed to help understanding, estimating or interpreting gravel transport in Alpine rivers. The conceptual model was discussed and applied to a field case made on the Arc River. Using the model, we also suggest a new dimensionless analysis for the construction of a bedload predicting model involving parameters describing bed arrangement, bed properties and fine sediment presence
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Yücel, Tuna. "Early-time, beta-hairpin peptide self-assembly and hydrogelation structure, kinetics, and shear-recovery /." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 136 p, 2009. http://proquest.umi.com/pqdweb?did=1654493371&sid=4&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Marx, Steffen, Gregor Schacht, Hans-Gerd Maas, Robert Koschitzki, and Guido Bolle. "Versuchsgrenzlastindikatoren bei Belastungsversuchen." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2011. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-76111.
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Die Zielstellung des Forschungsvorhabens ist die Entwicklung und Erprobung von speziellen Indikatoren, welche im Zuge einer Probebelastung für die sichere Beurteilung der Tragfähigkeit von Massivbaukonstruktionen mit geringem Ankündigungsverhalten geeignet sind. Der Begriff "Ankündigung“ bezieht sich dabei auf die beim Belastungsversuch wichtige Bestimmung der Versuchsgrenzlast, deren Überschreiten zu inakzeptablen Schädigungen führt und daher mit ausreichender Sicherheit ausgeschlossen werden muss.
Durch den Einsatz und vor allem die Kombination moderner Messverfahren kann eine wesentliche Verbesserung der Informationsqualität während des Belastungsversuches erreicht werden. Eine Echtzeitauswertung der Messergebnisse erlaubt die Definition objektiver Kriterien der Versuchsgrenzlast. Dadurch soll zukünftig gewährleistet werden, dass bereits minimales nichtlineares Strukturverhalten unmittelbar während des Versuches festgestellt und damit die Versuchsgrenzlast nahezu schädigungsfrei ermittelt werden kann.
Den Kernpunkt der Sensorik und Datenverarbeitung bilden flexibel einsetzbare photogrammetrische Verfahren zur automatisierten hochgenauen flächenhaften Erfassung von Schädigungen bei Probebelastungen aus Bilddaten von Digitalkameras mit permanenter Rechnerverbindung. Durch die Anwendung von speziellen Verfahren der Bildanalyse kann die Auswertung der Bilddaten weitestgehend automatisiert werden und in Echtzeit während des laufenden Versuchs erfolgen. Durch Subpixeloperatoren und geeignete Kalibrierverfahren können Genauigkeiten im Bereich weniger Mikrometer erzielt werden.
Dieser Abschlussbericht gibt einen Überblick über die bisher durchgeführten theoretischen und experimentellen Untersuchungen zur Anpassung und aufgabenspezifischen Entwicklung der gewählten Messverfahren (Photogrammetrie und Schallemissionsanalyse).
Diese wurden in Tastversuchen und Schubversuchen an Stahlbetonbauteilen ohne Bügelbewehrung erprobt und erlauben durch die Kombination der Messinformationen Schlussfolgerungen auf eine messbare Vorankündigung auch bei nicht-duktilen Massivbaukonstruktionen.
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Thompson, Charlotte E. L. "The role of the solid-transmitted bed shear stress of mobile granular material on cohesive bed erosion by unidirectional flow." Thesis, University of Southampton, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.398824.
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Marx, Steffen, Gregor Schacht, Hans-Gerd Maas, Frank Liebold, and Guido Bolle. "Versuchsgrenzlastindikatoren bei Belastungsversuchen II." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-130176.
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Ziel des Folgeantrages war die Entwicklung der photogrammetrischen Messtechnik zur onlinefähigen Anwendung bei In-situ-Belastungsversuchen. Dies wurde mit den in Kapitel 3 beschriebenen Ansätzen erfolgreich umgesetzt. Die gewählte künstliche Texturierung der Bauteiloberflächen stellte sich als sehr geeignet heraus, um bereits kleinste Strukturveränderungen beobachten und visualisieren zu können. Durch die Verwendung einer Industriekamera konnte die onlinefähige Bildanalyse und simultane Darstellung der Ergebnisse auf dem Bildschirm umgesetzt werden. Durch die Verwendung von Dreiecken und der Ermittlung der Hauptverzerrung jedes dieser Dreiecke wurden Bereiche hoher lokaler Dehnungen (Rissentwicklung) frühzeitig detektiert. Diese frühe und automatisierte Erkennung der Rissentwicklung ermöglicht und verbessert die Beurteilung des Tragzustandes des zu untersuchenden Bauteils erheblich.
Für die Beurteilung des Tragverhaltens von Stahlbetonbauteilen ohne oder mit zu geringer Bügelbewehrung wurden neben der Photogrammetrie die Schallemissionsanalyse, herkömmliche Verformungsmesstechniken und abschnittsweise Verformungsmessungen mit Neigungssensoren durchgeführt. Es zeigte sich, dass gerade die Kombination dieser Messverfahren zu einer erheblichen Verbesserung der Information über den Tragzustand des untersuchten Bauteils führte.
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Chen, Ke. "Le piémont nord du Tian Shan : cas d'école d'un front de chaîne immature." Phd thesis, Université d'Orléans, 2010. http://tel.archives-ouvertes.fr/tel-00597191.
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La chaîne actuelle du Tian Shan (Asie centrale) est considérée comme une conséquence directe de la réactivation d'une ceinture orogénique du Paléozoïque due à la collision Inde-Asie, au Cénozoïque. Un travail détaillé a été réalisé le long du piémont nord de la chaîne en intégrant les observations géologiques de terrain, analyses structurales, profils sismiques, nouvelles mesures des anomalies gravimétriques et des données de forages. Tout d'abord cette étude apporte de nouvelles preuves directes, à différentes échelles, sur l'existence d'un paléo-relief majeur le long du front nord du Tian Shan au cours du Mésozoïque, et plus particulièrement pendant le Jurassique. Deuxièmement, la quantité de raccourcissement calculée à travers cette ceinture de plis et chevauchements nord du Tian Shan est relativement faible et les structures reconnues le long du front de la chaîne présentent une hétérogénéité latérale forte. Ainsi, alors qu'un chevauchement du socle paléozoïque sur les séries sédimentaires mésozoïques et cénozoïques du bassin est remarquablement exposé le long de certaines vallées, d'autres sections montrent que les séries sédimentaires du Trias au Jurassique peuvent être suivies de manière continue, depuis le bassin jusque sur le toit du socle Paléozoïque où ils reposent en discordance relativement haut dans la chaîne. Quatre coupes géologiques ont été construites par l'intégration des données pluridisciplinaires acquises. La restauration de ces coupes montre que les taux de raccourcissement sont inférieurs à 20% et peuvent descendre à un minimum de 6%. Ces observations suggèrent que le piémont nord du Tian Shan est plutôt "jeune" et que la chaîne d'avant pays est encore à un stade primaire de son évolution tectonique. En d'autres termes, le piémont nord du Tian Shan peut être considéré comme un exemple type de front de chaîne immature.
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Franey, N. J. "A geological model of shear zone gold deposits in the Pietersburg Greenstone Belt, South Africa." Thesis, Rhodes University, 1987. http://hdl.handle.net/10962/d1007190.
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The Pletersburg greenstone belt Is located In South Africa, about 300 km northeast of Johannesburg. It hosts a significant amount of gold mineralization and just over 1000 kg of gold have been produced from Its various reefs and secondary deposits. The greenstone belt is interpreted as an Archean ophiolite complex. It comprlses a volcano-sedimentary succession (the Pletersburg Group) which Is subdivided Into a basal greenstone sequence, interpreted as oceanic crust, and an upper sedimentary cover sequence. A number of major shear zones, which are thought to represent thrusts that developed during the subduction of the greenstone sequence, form an integral part of the stratigraphy . Four stages of deformation (D₁-D₄) and four phases of metamorphism (H₁-H₄) (three of which are correlatable with the peak stages of deformation) are recognized. The primary gold deposits are all shear zones related. but they are subdivided into greenstone, sedimentation and granIte-hosted types. Geographically, they occur In three distinct goldfields: Eerstellng, Roodepoort and Marbastad. The greenstone-hosted · Plenaar-Doreen shear complex Is In the Eersteiing goldfield and hosts eight gold occurrences. Within the complex, Girlie North Reef is the 640m-long "pay" section of the Girlie North shear zone. This reef is characterized, macroscopically, by a Quartz-carbonate-chlorite-sulphlde assemblage and, mlcroscoplcally, by the presence of tourmaline, arsenopyrlte and Au. Geochemical evidence Indicates that mineralizing fluids were H₂O and CO₂-bearing and rich In S, K and Al. The wall rock alteratlon was Isochemlcal but Is manifest as a change In mineralogy from a hornblende + plagioclase assemblage to an actlnollte/tremollte + Quartz + clay assemblage. This Is best developed In the hangIng wall of the reef and is thought to have been caused by hydrogen ion metasomatism. The Arsenopyrite Reef was one of the main sediment-hosted shear zone gold producers In the Harabastad goldfield. This reef Is Interpreted as the basal margin of a shear zone whose top contact Is probably represented by the Quartz Vein Reef. The shear zone consists predomonantly of quartz and carbonate, and the two "pay" reefs are characterized by tourmallne. arsenopyrite and Au. No wall rock alteration was identified In this study, Based on the mineralogy and geochemical signature of the Girlie Nortn Reef and the Arsenopyrite Reef, It Is proposed that both were formed at the $The Pletersburg greenstone belt Is located In South Africa, about 300 km northeast of Johannesburg. It hosts a significant amount of gold mineralization and just over 1000 kg of gold have been produced from Its various reefs and secondary deposits. The greenstone belt is interpreted as an Archean ophiolite complex. It comprlses a volcano-sedimentary succession (the Pletersburg Group) which Is subdivided Into a basal greenstone sequence, interpreted as oceanic crust, and an upper sedimentary cover sequence. A number of major shear zones, which are thought to represent thrusts that developed during the subduction of the greenstone sequence, form an integral part of the stratigraphy . Four stages of deformation (D₁-D₄) and four phases of metamorphism (H₁-H₄) (three of which are correlatable with the peak stages of deformation) are recognized. The primary gold deposits are all shear zones related. but they are subdivided into greenstone, sedimentation and granIte-hosted types. Geographically, they occur In three distinct goldfields: Eerstellng, Roodepoort and Marbastad. The greenstone-hosted · Plenaar-Doreen shear complex Is In the Eersteiing goldfield and hosts eight gold occurrences. Within the complex, Girlie North Reef is the 640m-long "pay" section of the Girlie North shear zone. This reef is characterized, macroscopically, by a Quartz-carbonate-chlorite-sulphlde assemblage and, mlcroscoplcally, by the presence of tourmaline, arsenopyrlte and Au. Geochemical evidence Indicates that mineralizing fluids were H₂O and CO₂-bearing and rich In S, K and Al. The wall rock alteratlon was Isochemlcal but Is manifest as a change In mineralogy from a hornblende + plagioclase assemblage to an actlnollte/tremollte + Quartz + clay assemblage. This Is best developed In the hangIng wall of the reef and is thought to have been caused by hydrogen ion metasomatism. The Arsenopyrite Reef was one of the main sediment-hosted shear zone gold producers In the Harabastad goldfield. This reef Is Interpreted as the basal margin of a shear zone whose top contact Is probably represented by the Quartz Vein Reef. The shear zone consists predomonantly of quartz and carbonate, and the two "pay" reefs are characterized by tourmallne. arsenopyrite and Au. No wall rock alteration was identified In this study, Based on the mineralogy and geochemical signature of the Girlie Nortn Reef and the Arsenopyrite Reef, It Is proposed that both were formed at the same time. Textural evidence Indicates that tourmaline, arsenopyrite and Au were all very late In the paragenesis of minerallzatlon. The presence of tourmaline also Indicates a probable granite association. It Is proposed that the maln gold mineralizing event was synchronous with the Intrusion of granitoids (and therefore also with (D₁-D₄) and (H₁-H₄) and that most of the Au was derived from felsic magma. Gold was partitioned Into a magmatic hydrothermal fluid and then transported into the greenstone belt as a chlorIde complex. These magmatiC fluids were channelled up shear zones whIch had already been mineralized with a quartz-carbonate-chlorlte - sulphide assemblage by previous metamorphic fluidS. generated during the dynamic (D₂-related) H₂-phase of metamorphism. The Au was then deposIted as the result of a change In a fluid variable, such as temperature, pH, f0₂, or the activity of Cl (some Au may have been transported In a sulphur complex and so the activity of reduced 5 could also have been Important).
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Worthington, James R., Paul Kapp, Vladislav Minaev, James B. Chapman, Frank K. Mazdab, Mihai N. Ducea, Ilhomjon Oimahmadov, and Mustafo Gadoev. "Birth, life, and demise of the Andean-syn-collisional Gissar arc: Late Paleozoic tectono-magmatic-metamorphic evolution of the southwestern Tian Shan, Tajikistan." AMER GEOPHYSICAL UNION, 2017. http://hdl.handle.net/10150/626289.
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The amalgamation of the Central Asian Orogenic Belt in the southwestern Tian Shan in Tajikistan is represented by tectono-magmatic-metamorphic processes that accompanied late Paleozoic ocean closure and collision between the Karakum-Tarim and Kazakh-Kyrgyz terranes. Integrated U-Pb geochronology, thermobarometry, pseudosection modeling, and Hf geochemistry constrain the timing and petro-tectonic nature of these processes. The Gissar batholith and the Garm massif represent an eastward, along-strike increase in paleodepth from upper-batholith (similar to 21-7km) to arc-root (similar to 36-19km) levels of the Andean-syn-collisional Gissar arc, which developed from similar to 323-288Ma in two stages: (i) Andean, I-type granitoid magmatism from similar to 323-306Ma due to northward subduction of the Gissar back-arc ocean basin under the Gissar microcontinent, which was immediately followed by (ii) syn-collisional, I-S-type granitoid magmatism in the Gissar batholith and the Garm massif from similar to 304-288Ma due to northward subduction/underthrusting of Karakum marginal-continental crust under the Gissar microcontinent. A rapid isotopic pull-up from similar to 288-286Ma signals the onset of juvenile, alkaline-syenitic, post-collisional magmatism by similar to 280Ma, which was driven by delamination of the Gissar arclogite root and consequent convective asthenospheric upwelling. Whereas M-HT/LP prograde metamorphism in the Garm massif (650-750 degrees C/6-7kbar) from similar to 310-288Ma was associated with subduction-magma inundation and crustal thickening, HT/LP heating and decompression to peak-metamorphic temperatures (similar to 800-820 degrees C/6-4kbar) at similar to 2886Ma was driven by the transmission of a post-collisional, mantle-derived heat wave through the Garm-massif crust.
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Cuthbertson, Alan J. S. "The motion of fine sand particles in turbulent open channel shear flows over porous bed conditions." Thesis, University of Glasgow, 2001. http://theses.gla.ac.uk/2489/.
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The current study aims to investigate the physical mechanisms controlling fine sediment transport within open channel shear flows over porous beds, with particular emphasis on the role of flow turbulence in particle settling and deposition processes. Preliminary visualisation experiments used a VHS camera to observe the near-bed motion of sand particles and their behaviour within the surface layer of a rhombically-packed bed of uniform spheres. Measurement of near-bed particle trajectories indicate that turbulent particle fall velocities w's are generally larger than fall velocities measured in still water ws, most notably for finer sand grades. Distinctive modes of particle behaviour observed at the bed interface also suggest that flow-separation eddies, generated within surface interstices, have a primary influence on subsequent particle motion, i.e. deposition or re-entrainment. Similar particle behaviour is also displayed in a natural gravel bed. A more detailed analysis of sand particle motion in turbulent open channel flow was carried out employing a high-speed camera and particle-tracking technique to record and analyse particle trajectories within different flow regions. The non-dimensional ratio of measured particle fall velocity w's and still water fall velocity ws was used to indicate the relative enhancement of vertical particle motion within the turbulent flow conditions. Experiment-averaged values of this ratio reveal that particle fall velocities are generally enhanced (i.e. w's/ws > 1) in recorded near-bed and intermediate flow regions (z/H 0.5) and hindered (i.e. w's/ws < 1) in a recorded outer flow region (z/H 0.5). The ratio w's/ws also reveals a general tendency to increase with decreasing grain size di. Vertical profiles of the normalised particle fall velocity w's/u* are shown to be analogous to turbulence intensity distributions (u' rms/u* and w'rms/u*), with the highest values of w's/u* occurring in the near-bed region and coinciding approximately with the regions of highest turbulence activity. This clearly implies the existence of turbulence-enhanced particle fall velocities within the flow conditions considered. Application of a quadrant analysis technique reinforces this notion, revealing further similarities between conditioned turbulent fluid fluctuations and particle motions, in particle, the dominance of 'inrush' events (quadrant 4) in the near-bed flow and 'ejection' events (quadrant 2) away from the bed.
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Sime, Louise C. "Reach-scale spatial variation of grain-size, shear stress, and bedload transport in gravel-bed rivers." Thesis, University of Sheffield, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.401128.
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Fox, Michael. "Statistical structure of plasma turbulence from BES measurements in MAST and the effect of flow shear." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:9d109810-79e7-4403-bb4c-f58b7acbd6c1.
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The suppression of turbulent transport is a key requirement for enabling nuclear fusion to become a viable energy source. One possible route to achieving this suppression is through toroidal flow shear. We investigate the effect that flow shear has on the structure of turbulence by analysing data from both measurements of the fluctuating intensity field using the Beam-Emission-Spectroscopy (BES) diagnostic on the spherical tokamak MAST, as well as from numerical simulations of the fluctuating density field in MAST. We develop a procedure to map from the correlation parameters of the intensity field to the correlation parameters of the density field. This procedure is illustrated using the MAST BES system and the validity of the underlying assumptions is tested on fluctuating density fields generated by direct numerical simulations using the gyrokinetic code GS2. By using this procedure, we demonstrate how, in experiment, the flow shear associated with the differential toroidal rotation of tokamak plasmas breaks an underlying symmetry of the turbulent fluctuations imposed by the up-down symmetry of the magnetic equilibrium. Indeed, in both experimental BES measurements and gyrokinetic simulations, this symmetry breaking in ion-scale turbulence in MAST is shown to manifest itself as a tilt of the spatial correlation function and a finite skew in the distribution of the fluctuating intensity (density) field. The tilt is a statistical expression of the "shearing" of the turbulent structures by the mean flow. The skewness of the distribution is related to the emergence of long-lived density structures in sheared, near-marginal plasma turbulence. The extent to which these effects are pronounced is argued (with the aid of the simulations) to depend on the distance from the non- linear stability threshold. Away from the threshold, the symmetry is effectively restored.
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Hedin, Baastrup Hugo. "Structural Reconnaissance Mapping of the Nasa Basement Window, Southern Norrbotten Caledonides." Thesis, Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-72044.
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Too few documentative descriptions exist from the reactivated Proterozoic Nasa Basement window in Sweden. This re-exposed crustal piece predominantly consisting of 1.8 Ga granite and volcanic basement rock lack structural evidences on maps. The Western Gneiss region gave example of how rocks in extreme cases may experience protolith overprinting through collisional vertical granite basement subduction to eclogite ambient conditions, which would give traces in metamorphic quartz (coesite), muscovite, pyroxene and kyanite, and increased densities. Preliminary indications from literature points towards a locally passive Nasa Basement with limited translation, but because of too little documentation it cannot be assured metamorphic inertia under fluid absence has been unimportant in the basement evolution. To address this highly structural issue, field reconnaissance mapping and sampling was carried out, and aimed to achieve a structural characterisation of historic deformation back to Proterozoic time. Observations were collected from 166 outcrop vicinities, and 17 of 27 carefully examined thin sections aimed to describe microscopic structures, in addition to mineral relation to metamorphic minerals. Collected evidences in this project encompass a Proterozoic macroscopic concentric fold with axis striking NW-SE, as well as, mesoscopic folds striking WNW-ESE. Tectonic movements record syn-collisional top-SE and post- collisional top-SW translation, which truncate weakly shortened and foliated blocks. Basement blocks locally preserve igneous coarse but weakly recrystallized texture fabrics. Overall optically produced paleothermometry indicates low- to medium grade facies conditions of deformation, through widespread bulging recrystallization, occasional subgrain rotation and rare grain boundary migration in quartz. Feldspar response to deformation is brittle and rarely ductile. Hydrous biotite, chlorite and epidote are abundant. Mineralogy together with an observed average density of 2,6 g/cm3 can possibly reject the idea of unreacted local continental subduction to eclogite depths, due to the overall presence of hydrous mineral phases. Top-to-the shear sense proves Caledonian reactivation, but Bourguer anomaly indicates at least locally an important limited translation. NW-SE striking lineaments and strikes of foliation show best accordance with lineaments mapped in Norway and alignment with tectonic contacts in the Baltica interior, and do so show the best examples of candidates for Proterozoic structures.
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Valentine, Kendall. "Characterization of the bed, critical boundary shear stress, roughness, and bedload transport in the Connecticut River Estuary." Thesis, Boston College, 2015. http://hdl.handle.net/2345/bc-ir:104550.
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Thesis advisor: Gail C. KinekeThis study characterizes the bed of the Connecticut River estuary in terms of grain size and bedforms, and relates these to river discharge, tidal currents, and sediment transport. Over four field excursions, sediment cores were collected, in addition to bathymetry surveys, and water column measurements. A three-dimensional circulation and sediment transport model calculated boundary shear stress over the same time. The bed of the estuary is composed mostly of sand, with small amounts of fine sediments. Deposition of fine sediments is limited by the landward extent of the salt intrusion. Large bedforms are oriented seaward. The critical shear stress for the median grain size is exceeded each tidal cycle. Bedload transport is dominantly seaward during high discharge conditions, but varies during low discharge. Bathymetry surveys from previous studies and this study show consistent bedform fields over 25 years. Bedforms observed in the field reflect typical conditions rather than extreme events
Thesis (MS) — Boston College, 2015
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Earth and Environmental Sciences
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Santos, Ana Paula Carneiro dos. "Participação da via de sinalização da beta-arrestina na produção de óxido nítrico induzido pelo shear stress." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/5/5166/tde-01042015-150141/.
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As células endoteliais são capazes de converter o estímulo mecânico em sinais intracelulares e produzir fatores vasoativos como o óxido nítrico (oNO). Evidências recentes sugerem que as beta-arrestinas desempenham um papel importante não somente na dessensibilização e internalização de receptores acoplados à proteína G (GPCR) como também na mecanotransdução. Nós testamos a hipótese de que células endoteliais submetidas ao shear stress (SS) produzem oNO por meio da ativação da via de sinalização dependente de beta-arrestina. Para tal, células endoteliais de veia safena (hSVEC) foram transfectadas com siRNA contra as isoformas 1 e 2 da beta-arrestina e, posteriormente, submetidas ao SS (15 dinas/cm2) durante 10 min. Nós encontramos que as SVEC silenciadas para a beta-arrestina 1/2 (70%) exibiram uma menor produção de nitrito no meio de cultura em resposta ao SS (166±17 vs. 326±44% comparado com hSVEC transfectadas com siRNA controle). Além disso, o silenciamento da beta-arrestina 1 e 2 preveniu os níveis de fosforilação da Akt no resíduo de serina 473 e a fosforilação da eNOS no resíduo de serina 1177, enquanto que a fosforilação da ERK 1/2 manteve-se inalterada. Curiosamente, análises de imunoprecipitação mostraram que a beta-arrestina interage com caveolina-1, um mecanossensor do shear stress, mas não é influenciado pelo SS. Além disso, na situação estática, a beta-arrestina encontra-se em uma localização perinuclear e, após o SS, adquiriu um padrão mais difuso no citosol. Coletivamente, esses dados sugerem que a beta-arrestina e a sinalização downstream Akt/ eNOS são necessárias para a produção de oNO induzido por shear stress em células endoteliais vasculares humanaEndothelial cells are capable of converting mechanical stimuli into intracellular signals generating vasoactive factors such as nitric oxide (oNO). Recent evidence suggests that beta-arrestins play a role not only on G protein-coupled receptors (GPCR) desensibilization but also in mechanotransduction. We tested the hypothesis that beta-arrestin and its downstream signaling influence laminar shear stress (SS)-induced oNO production by endothelial cells. Towards this end, human saphenous vein endothelial cells (hSVEC) transfected with siRNA against beta-arrestins isoforms 1 and 2 were subjected to SS (15 dynes/cm2, 10 minutes). We found that the SS-induced production of nitrite in the cell culture medium from down-expressed beta-arrestin 1/ 2 (70%) SVEC decreased (166±17 vs. 326±44% compared to wild-type hSVEC; P < 0.001). The beta-arrestin 1 and 2 down-regulation in SVEC also inhibited the phosphorylation levels of Akt at the serine residue 473 and the phosphorylation levels of eNOS at the serine residue 1177, whereas ERK phosphorylation remained unchanged. Interestingly, immunoprecipitation analysis showed that beta-arrestin interacts with caveolin-1, a shear stress mechanosensor, which is not influenced by SS despite the fact that the static perinuclear localization of beta-arrestins changed to the cytosol upon SS. Collective these data suggest that beta-arrestin and Akt/eNOS downstream signaling are required for shear stress-induced nitric oxide production in human vascular endothelial cells
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Gagnon, Émilie. "Investigation of Transpressive Deformation Zones in the North Caribou Greenstone Belt (NW Superior) and Relationships with Regional Metamorphism: Implications for the Technothermal Evolution during Archean Cratonization." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32454.
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The Archean North Caribou greenstone belt (NCGB) possesses abundant transpressive deformation zones on its northern margins, which appear to have formed under amphibolite facies conditions. Protracted deformation and regional metamorphism are coeval with widespread magmatism and accretion events in the Superior Province, yet the importance of these shear zones in the tectonic evolution of the NCGB is equivocal. Structural analyses support a transpressive system that strongly implicates horizontal tectonism. This is partly in contrast with some currently proposed models for Archean greenstone belts suggesting synchronous vertical and horizontal movements. Geochemical and microstructural analyses from shear zones indicate heterogeneous deformation/fluids conditions on a km-scale. Monazite and mica geochronological ages indicate metamorphism and deformation occurring during the amalgamation of the Superior craton from ca. 2.75 to 2.4 Ga. The high metamorphic grade background may obscure tectonic signatures, yet some structural and geochemical characteristics remain consistent with other greenstone belts where vertical and horizontal displacement are recorded.
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Yang, Shan [Verfasser]. "HCF property improvement through microstructure optimization and shot peening in (alpha + beta) Ti alloys / Shan Yang." Clausthal-Zellerfeld : Universitätsbibliothek Clausthal, 2014. http://d-nb.info/1060881055/34.
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Shen, Bo [Verfasser], and Engelbert [Akademischer Betreuer] Westkämper. "Beitrag zur Modellierung und Simulation des Strahlzerfalls bei der pneumatischen Lackzerstäubung / Bo Shen ; Betreuer: Engelbert Westkämper." Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2020. http://d-nb.info/1219509841/34.
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Jackson, Christopher. "A microstructural kinematic study of selected shear zones in the Hartbees River Thrust Belt, northeastern Namaqua Tectonic Province." Thesis, Rhodes University, 1992. http://hdl.handle.net/10962/d1005588.
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The Hartbees River Thrust Belt (HRTS) is a 40-60 km wide, southwest-vergent zone of complex structure, lithostratigraphy and high-grade metamorphism in the northeastern part of the mid-Proterozoic Namaqua Tectonic Province. The HRTS comprises the boundary zone separating the Bushmanland and Gordonia Subprovinces of the Namaqua Province. A knowledge of the movement histories of major ductile shear zones within the HRTS is fundamental to understanding the tectonic development of the belt, and Namaqua tectogenesis as a whole. In spite of this, no detailed microstructural kinematic studies have been attempted and the movement histories and age relationships of these shear zones have not been described in detail. This thesis represents a detailed microstructural kinematic study of a representative suite of orientated samples of mylonitic rocks, collected from five ductile shear zones within the HRTS. These shear zones include the Neusspruit Lineament, the Kakamas shear zone (KSZ), the Hugosput shear system (HSS), the Rozynenbosch-Ganzenmond shear zone (RGSZ) and the Graafwater shear system (GSS). Accepted modern methods of microstructural kinematic analysis were applied to samples of mylonite from these shear zones, in order to determine the precise orientation of the kinematic vectors, and the sense and relative ages of movements on each of the shear zones. Shear sense criteria, including composite SoC planar fabrics and shear band foliations, asymmetrical porphyroclast systems, mica-fish, oblique grain-shape and subgrain fabrics, asymmetrical microfolds, and the displacement of fractured rigid grains, together with a well-developed mylonite elongation lineation, conclusively indicate that SSW-directed thrusting occurred along the HSS, RGSZ, GSS and possibly along the Neusspruit Lineament, while normal, top-to-NE movements occurred on the Neusspruit Lineament, KSZ and HSS. Rare transposition criteria, and textural and paragenetic contrasts between syn-kinematic fabrics, strongly suggest that the phase of normal, top-to-NE movement seen in the northeastern HRTS shear zones is younger than the more widespread top-to-SW thrusting event. On the basis of mesoscopic structural criteria, SSW-directed thrusting is correlated with the D₂ deformation event in the HRTS. The mylonite zones have been refolded by ENE-SSW trending F₃ crossfolds, whose demonstrated coaxial relationship to the mylonite elongation lineation precluded reorientation of primary kinematic vectors. In the southwestern HRTS, primary thrust vectors have been reoriented by right-lateral, strike-slip shearing adjacent to the Pofadder Lineament during D₄. Simple shear dispersion of mylonite lineations related to normal movement, suggests that they too have been modified by D₄ shearing, and this constrains the timing of extensional movements to post-D₂ and pre- or syn-D₄. Syn-kinematic mineral assemblages, rheological criteria and the annealing states of the mylonites, provide insight into the thermotectonic evolution of the shear zones. A model is proposed in which the movement histories of shear zones within the HRTS are explained in terms of a typical orogenic cycle, involving crustal thickening by thrusting during a compressional orogenic phase, followed by collapse of the thickened crust during an extensional taphrogenic phase.
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Marx, Steffen, Gregor Schacht, Hans-Gerd Maas, Frank Liebold, and Guido Bolle. "Versuchsgrenzlastindikatoren bei Belastungsversuchen II: Forschungsinitiative Zukunft Bau." Technische Universität Dresden, 2013. https://tud.qucosa.de/id/qucosa%3A27350.
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Ziel des Folgeantrages war die Entwicklung der photogrammetrischen Messtechnik zur onlinefähigen Anwendung bei In-situ-Belastungsversuchen. Dies wurde mit den in Kapitel 3 beschriebenen Ansätzen erfolgreich umgesetzt. Die gewählte künstliche Texturierung der Bauteiloberflächen stellte sich als sehr geeignet heraus, um bereits kleinste Strukturveränderungen beobachten und visualisieren zu können. Durch die Verwendung einer Industriekamera konnte die onlinefähige Bildanalyse und simultane Darstellung der Ergebnisse auf dem Bildschirm umgesetzt werden. Durch die Verwendung von Dreiecken und der Ermittlung der Hauptverzerrung jedes dieser Dreiecke wurden Bereiche hoher lokaler Dehnungen (Rissentwicklung) frühzeitig detektiert. Diese frühe und automatisierte Erkennung der Rissentwicklung ermöglicht und verbessert die Beurteilung des Tragzustandes des zu untersuchenden Bauteils erheblich.
Für die Beurteilung des Tragverhaltens von Stahlbetonbauteilen ohne oder mit zu geringer Bügelbewehrung wurden neben der Photogrammetrie die Schallemissionsanalyse, herkömmliche Verformungsmesstechniken und abschnittsweise Verformungsmessungen mit Neigungssensoren durchgeführt. Es zeigte sich, dass gerade die Kombination dieser Messverfahren zu einer erheblichen Verbesserung der Information über den Tragzustand des untersuchten Bauteils führte.
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Shen, Chong [Verfasser]. "Epiphanie und Mnemopoesie : Motiv und Struktur des Vorübergehens bei Stefan George und Hugo von Hofmannsthal / Chong Shen." Berlin : Freie Universität Berlin, 2019. http://d-nb.info/1188613626/34.
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Pfahler, Matthias Hermann Christian [Verfasser]. "Point Shear Wave Elastographie des Pankreas bei Patienten mit Mukoviszidose – ein Vergleich mit gesunden Probanden / Matthias Hermann Christian Pfahler." Ulm : Universität Ulm, 2019. http://d-nb.info/1177882523/34.
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Jeffcoate, Penelope. "Experimental and computational modelling of 3-D flow and bed shear stresses downstream from a multiple duct tidal barrage." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/experimental-and-computational-modelling-of-3d-flow-and-bed-shear-stresses-downstream-from-a-multiple-duct-tidal-barrage(13b4b1d2-d144-4510-bc46-50a25739e41c).html.
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The near-field depth-varying velocities and resulting bed stresses downstream from a tidal barrage have not previously been studied. The flow through and downstream of a row of seven open draft tubes in a barrage has been investigated through laboratory experiment in a wide flume, 3-D RANS CFD simulation and 2-D depth-averaged computation. When there is no turbine representation and hence negligible swirl in the draft tubes, agreement between the experiments and 3-D modelling is shown to be good, including the prediction of an asymmetric Coandă effect. With the addition of bulb bodies and vanes creating swirl in the draft tubes the velocity profiles are changed, with increased swirl directly downstream from the draft tubes and throughout the entire flume cross-section further from the barrage. The addition of rotors did not significantly alter the flow field patterns, for the stator/rotor combinations presented here. 3-D CFD could not accurately predict the velocity profiles resulting from the swirl in the ducts. The experiments and 3-D model shows that bed shear stress can be magnified markedly near the barrage particularly where the jets become attached to the bed. At full-scale this would result in a fully mobile bed with sand of typical grain size 1mm. One aim was to determine the distance downstream where depth-averaged modelling gives reasonable prediction and this is shown to occur around 20 tube diameters (20D) downstream of the barrage. Upstream of this, the depth-averaged modelling inaccurately predicts water level and bed shear as well as the 3-D flow field. The addition of swirl cannot be modelled using 2-D modelling, but by 20D downstream there is minimal velocity variation transversely and throughout the depth, indicating depth-averaged modelling would be applicable from this distance.
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Maestre, Heredia Jorge. "Towards the application of the isogeometric boundary element analysis to fluid mechanics: non-linear gravity waves and dynamics of deformable capsules in shear flows." Doctoral thesis, Universitat Rovira i Virgili, 2017. http://hdl.handle.net/10803/401587.
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En aquesta tesi es desenvolupa un model numèric eficient i robust per a l’anàlisi de problemes fluid-dinàmics, que posteriorment es valida i s’aplica a dues noves configuracions: (1) les onades generades per una hidroala submergida i (2) la dinàmica d'una càpsula deformable en un flux pulsàtil. El model es basa en el Mètode dels Elements de Contorn (MEC) integrat amb la tecnologia de NURBS i T-spline. Aquesta tècnica es coneguda com Anàlisi Isogeomètric (AIG) i té certs avantatges. El més atractiu és que permet una integració directa entre programes moderns de disseny gràfic (CAD) i eines d’anàlisi numèric, eliminant així laboriosos passos intermedis com la generació de la malla. Aquesta tesi es divideix en dos blocs.
El primer bloc tracta sobre la simulació de propagació d’onades no lineals gravitacionals i de la interacció onades-estructures. L’anàlisi d’aquest fenomen és útil per a predir la generació i propagació de tsunamis així com és indispensable per al disseny d’esculleres i estructures flotants. S’assumeix que el fluid és invíscid i irrotacional, resultant una equació de Laplace que es resol mitjançant el MEC. Es resolen diversos exemples en els que es demostra la precisió i estabilitat temporal del model numèric. Addicionalment es simula el front d’onades generat per una hidroala submergida.
En el segon bloc s’aplica el AIG a l’estudi del comportament de microcàpsules deformables suspeses en fluxos. La dinàmica de microcàpsules deformables comporta importants implicacions en un ampli rang d’aplicacions biomèdiques i industrials. El AIG-MEC s’utilitza per a resoldre l’equació del fluid mentre que es desenvolupa una formulació basada en el AIG-Mètode dels Elements Finits (MEF) per a l’anàlisi de la mecànica de la membrana. Es resolen diversos exemples en els que es mostra la capacitat del mètode per a la simulació de càpsules sotmeses a grans deformacions. Finalment s’estudia la dinàmica d’una càpsula en un tub amb flux pulsàtil.En esta tesis se desarrolla un modelo numérico eficiente y robusto para el análisis de problemas fluido-dinámicos, que posteriormente se valida y se aplica a dos nuevas configuraciones: (1) las ondas generadas por un hidroala sumergida y (2) la dinámica de una cápsula deformable en un flujo pulsátil. El modelo se basa en el Método de los Elementos de Contorno (MEC) integrado con la tecnología NURBS and T-spline. Esta técnica es conocida como Análisis Isogeométrico (AIG) y posee ciertas ventajas. La más atractiva es que permite una directa integración entre modernos programas de diseño grafico (CAD) y herramientas de análisis numérico, eliminando así laboriosos pasos intermedios como la generación de la malla. Esta tesis se divide en dos bloques. El primer bloque trata sobre la simulación de propagación la de ondas de gravedad no lineales e la interacción olas-estructuras. El análisis de este fenómeno es útil para predecir la generación y propagación de tsunamis así como es indispensable para el diseño de rompeolas y estructuras flotantes. Se asume que el fluido es inviscido e irrotacional, resultando una ecuación de Laplace que se resuelve mediante el MEC. Se resuelven varios ejemplos en los que se demuestra la precisión y estabilidad temporal del modelo numérico. Adicionalmente se simula el frente de olas generados por una hidroala sumergida. En el Segundo bloque se aplica el AIG al estudio del comportamiento de microcápsulas deformables suspendidas en un flujo. La dinámica de microcápsules deformables conlleva importantes implicaciones en un amplio rango de aplicaciones biomédicas e industriales. El AIG-MEC se usa para resolver la ecuación del fluido mientras que se desarrolla una formulación basada en el AIG-Método de los Elementos Finitos (MEF) para el análisis de la mecánica de la membrana. Se resuelven varios ejemplos en los que se muestra la capacidad del método para la simulación de cápsulas sujetas a grandes deformaciones. Finalmente se estudia la dinámica de una cápsula en un tubo con un flujo pulsátil.
In this Thesis an efficient and robust numerical model for the analysis of fluid dynamic problems has been developed, validated and applied to two novel fluid flow configurations: (1) the waves generated by a submerged foil and (2) the dynamics of microcapsules in pulsating shear flows. The model is based on the Boundary Element Method (BEM) integrated with the NURBS and the T-spline frameworks. This technique is known as Isogeometrical Analysis (IGA) and it offers several advantages. The most attractive is that it allows a direct integration between modern Computer Aid Design geometric systems and numerical engineering analysis tools, removing intermediate steps as the mesh generation. This Thesis is divided into two blocks. The first block deals with the simulation of the propagation of non-linear gravity waves and of the wave-structure interactions. The analysis of this phenomenon is useful to predict the generation and propagation of tsunamis and it is indispensable for the design of breakwaters and floating structures. The flow is assumed to be inviscid and irrotational and the resulting Laplace's equation is solved using BEM. Some benchmark examples are considered to show the temporal accuracy and stability of the method. In addition, the simulation of the waves generated by submerged foils is reported. In the second block the IGA is applied to analyze the behavior of deformable microcapsules in shear flows. The dynamics of deformable capsules have important implications in a wide range of biolomedical and industrial applications. The IGA-BEM is used to solve the Stokes flow equation and an IGA-Finite Element Method (FEM) is developed for the analysis of the capsule mechanics. Some benchmark examples are solved to demonstrate the capability of the present approach for the simulation of capsules subjected to large deformation. Finally, the dynamics of a deformable capsule in a tube under a pulsatile flow is analyzed.
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Yang, Shan [Verfasser], and Oliver [Akademischer Betreuer] Speck. "Bestimmung kortikaler Dicke mit räumlich hoch- und ultra-hochaufgelöster MRT bei 7 Tesla / Shan Yang. Betreuer: Oliver Speck." Magdeburg : Universitätsbibliothek, 2014. http://d-nb.info/1060097508/34.
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Shen, Qiu [Verfasser], and Anton Friedrich [Akademischer Betreuer] Koch. "Sein und Nichts. Welt und Ding: Drei Stationen des Seinsdenkens bei Heidegger / Qiu Shen ; Betreuer: Anton Friedrich Koch." Heidelberg : Universitätsbibliothek Heidelberg, 2021. http://d-nb.info/1237499534/34.
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Kalbfleisch, Netasha. "Crustal-scale Shear Zones Recording 400 m.y. of Tectonic Activity in the North Caribou Greenstone Belt, Western Superior Province of Canada." Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/23308.
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A series of crustal-scale shear zones demarcates the northern and eastern margins of the North Caribou greenstone belt (NCGB), proximal to a Mesoarchean terrane boundary in the core of the western Superior Province of Canada. The dominant deformation produced a pervasive steeply dipping fabric that trends broadly parallel to the doubly arcuate shape of the belt and was responsible for tight folding the banded iron formation host to Goldcorp’s prolific gold deposit at Musselwhite mine. The shear zones in the North Caribou greenstone belt are of particular interest because of their ability to channel hydrothermal fluids with the potential to bear ore and cause alteration of the middle to shallow crust. Shear zones are commonly reactivated during subsequent tectonism, but exhibit a consistent and dominant dextral shear sense across the belt; fabric-forming micas and chlorite are generally Mg-rich. Although garnets samples from within the shear zones are dominantly almandine, they possess variable geochemical trends (HREEs of >2 orders of magnitude) and can be syn-, intra-, or post-tectonic in origin. In situ geochronological analysis of zircon (U-Pb) and monazite (total-Pb) in high strain rocks in and around the NCGB, interpreted in light of in situ geochemical analysis of garnet and fabric-forming micas and chlorite, reveals four relatively discrete events that span 400 million years. Metamorphism of the mid-crust was coeval with magmatism during docking of the Island Lake domain at c. 2.86 Ga and subsequent terrane accretion at the north and south margins of the North Caribou Superterrane from c. 2.75 to 2.71 Ga. Transpressive shear at c. 2.60 to 2.56 Ga and late re-activation of shear zones at c. 2.44 Ga produced a steeply-dipping pervasive fabric, and channeled fluids for late crystallization of garnet and monazite recorded in the Markop Lake deformation zone. These observations implicate a horizontal tectonic model similar to the modern eastern Pacific plate margin. Further, this study highlights the caution that should be exercised when using traditional rock forming metamorphic minerals (mica, chlorite, garnet) when attempting to vector into zones of hydrothermal alteration within midcrustal rocks.
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Mayoral, Helen. "Particle Size, Critical Shear Stress, and Benthic Invertebrate Distribution and Abundance in a Gravel-bed River of the Southern Appalachians." Digital Archive @ GSU, 2011. http://digitalarchive.gsu.edu/geosciences_theses/31.
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To determine the relationship between the abundance and density of benthic invertebrates, and the critical shear stress of individual grain sizes, a reach along Smith Creek, was divided into ten 2m x 2m quadrants. Within each quadrant, five randomly selected clasts for each grain size ranging from 2.26 to 25.6 cm were cleaned for benthic invertebrates. Wolman pebble counts for each quadrant were also conducted and used to determine the critical Shields stress per grain size fraction from the model given by Wiberg and Smith (1987) that explicitly accounts for particle hiding/sheltering effects in mixed-bed rivers. Particle entrainment values were then compared with estimated bankfull Shields stress values to determine sediment transport potential during bankfull flow. Invertebrate abundance was strongly positively correlated with critical Shields stress up to the 18.0 cm grain size, indicating a preference for certain grain sizes; while density was positively correlated with all grain sizes present.
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Mazzi, Fabio. "Influence of shear force and analysis of operating parameters on filter cake stability and deliquoring in a belt filter press." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020.
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Belt filter press is among those technical set-ups used for mechanical deliquoring of sludge. The purpose of this study is to analyze the effect of operating parameters in the high-pressure zone on the deliquoring performance and cake stability. The investigated operation parameters are the velocity of the belt, the number of pressure cycles together with the exerted pressure, and the quantity of substance. The deliquoring performance is evaluated in terms of final cake dryness and specific throughput, while the stability is defined as the capacity of the cake to suffer a certain level of pressure without an excessive spreading or breaking its structure.
Experiments are performed with two different types of sludge. To estimate the effect of each process parameter, different series of experiments are carried out in the high-pressure zone simulation equipment. In each series, only one parameter is modified to isolate the single effect.
Other series of experiments are carried out in the high-pressure zone simulation equipment to investigate the re-wetting and to analyse the so-called F factor used to link the experimental result with the specific throughput of a full-scale equipment. Finally, the effect of shear force on the deliquoring performance is studied through the use of a filter press unit cell.
The belt speed has an influence on the final dry solid content: a low belt speed produces drier cakes with lower lateral sludge migration on the belt. At low belt speed, pressure is more gently applied to the initial sludge, enabling a slow structuring of the cake and leading to better water release.
The number of pressure cycles has an influence on the cake stability which means that the pressure must be gradually increased during the belt filter press to avoid excessive migration.
Re-wetting occurs and it has a negative effect on the final dry solid content.
The combination of shear and compression force leads to an effective improvement on deliquoring performance.
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Hennig, Theres. "An endothelium-derived elastase as mediator of shear stress-induced outside-in signaling via integrin avb3 [alpha-v-beta-3]." kostenfrei, 2010. http://d-nb.info/1001718437/34.
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Abolins, Nicholas Ivars. "A structural investigation of a section of the Greenhill-Montacute Heights Shear Zone, southern Adelaide Fold-Thrust Belt, South Australia /." Title page, contents and abstract only, 2000. http://web4.library.adelaide.edu.au/theses/09SB/09sba1542.pdf.
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Brix, Michèle [Verfasser]. "Untersuchung klinischer und molekularer Parameter der Endothelfunktion nach Individual Shear Rate Gegenpulsationstherapie bei Patienten mit einer peripheren arteriellen Verschlusskrankheit / Michèle Brix." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2017. http://d-nb.info/1148425160/34.
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Dornelas, Breno Almeida. "Análise experimental da tensão de cisalhamento mínima para suspensão de partículas em um leito horizontal." Universidade Federal do Espírito Santo, 2009. http://repositorio.ufes.br/handle/10/6248.
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Previous issue date: 2009-12-22A remoção eficiente de cascalhos ainda é um desafio na perfuração de poços para produção de óleo e gás. O ponto crítico corresponde ao estágio horizontal da perfuração que intrinsecamente tende a formar um leito de partículas sedimentadas na parte inferior do poço em perfuração. A erosão desse leito de cascalhos oriundos do solo perfurado depende principalmente da tensão de cisalhamento promovida pelo escoamento do fluido de perfuração. Utilizando uma bancada experimental, composta de sistema para circulação de fluidos, caixa de cascalhos, unidade de bombeio e equipamentos de medição, investiga-se a tensão de cisalhamento mínima necessária para a erosão de um leito em função das propriedades do fluido e das partículas do leito. A área de observação consiste de uma caixa abaixo da linha de escoamento, para partículas calibradas de areia, em um duto de acrílico. Para as medições iniciam-se as bombas com baixa rotação e são feitos incrementos de freqüência. A cada patamar de freqüência são capturadas imagens de partículas carreadas pelo escoamento, registrando a vazão estabelecida. Com a análise do processamento das imagens define-se o momento em que o carreamento das partículas deixa de ser aleatório e esporádico e começa a ser permanente. A tensão de cisalhamento é determinada pela Correlação PKN (de Prandtl, von Kármán e Nikuradse) a partir da vazão mínima necessária para o arraste. Os resultados são obtidos para o escoamento de água e de solução águaglicerina
The efficient hole cleaning is still a challenge in the wellbore drilling for production of oil and gas. The critical point is the horizontal drilling that inherently tends to produce a bed of sediment particles at the bottom of the well. The erosion of this cuttings bed depends mainly on the shear stress promoted by the flow of drilling fluid. The shear stress required to drag cuttings bed is investigate according to the fluid and particles properties, using an experimental assembly, composed of a loop for circulation of fluids, of a particle box, of a pump system, camera and measuring equipment. The area of observation consists of a box below the line of flow, for calibrated sand particles, in an acrylic duct. The test starts with the pumps in low frequency and are made the increments. At each level of frequency are captured images of particles carried and it is records the established flow rate. The erosion criteria is defined when the drag particle no longer be random and sporadic, and begins to be permanent. The shear stress is determined by the PKN correlation (by Prandtl, von Kármán, and Nikuradse) from the minimum flow rate necessary to start the erosion process. Results were obtained for the flow of water; and of water and glycerin solution
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Louis, Stephen. "Continuer à irriguer quand les lacs-réservoirs de barrage souffrent de taux de sédimentation sévères - Recommandations d'amélioration de la gestion du principal canal d'irrigation alimenté par l'ouvrage répartiteur de Canneau (Haïti)." Doctoral thesis, Universite Libre de Bruxelles, 2019. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/288808.
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L’État haïtien, pour faire face à l’insécurité alimentaire que connaît sa population (à croissance rapide et à faible revenu), s’appuie particulièrement sur la Vallée du département de l’Artibonite qui constitue depuis toujours le véritable grenier agricole du pays, en fournissant, à elle seule, plus de 80% de la production rizicole nationale. Cette production agricole assure non seulement les besoins alimentaires de la population locale, mais également ceux particuliers des départements voisins (Ouest, Nord et Centre).L’irrigation de cette vaste plaine agricole (32400 ha de terres agricoles irrigables) est garantie, à plus de 75%, par le réseau d’irrigation établi en rive Gauche de l'ouvrage-partiteur de Canneau, alimenté par un Canal principal (CMRG) ayant un débit nominal de 40 m3/s.Néanmoins, ce Partiteur, source d’approvisionnement exclusive du CMRG, est lui-même régulé par le Barrage-réservoir de Péligre qui se trouve à 70 km plus en amont sur le fleuve de l’Artibonite. En termes hydrauliques, nos travaux ont d'abord examiné la situation du réservoir de Péligre. Alors qu'au moment de la construction il était initialement prévu d’y stocker 607 Mm3, il ne reste plus aujourd'hui qu'à peine 40% de cette capacité utile, en raison des dépôts sédimentaires qui se sont constitués année après année derrière le barrage.Cette sédimentation spectaculaire (due à l’érosion des bassins versants amont fort dégradés), combinée aux déficits pluviométriques, provoque en période d’étiage une rareté d’eau, des lâchers insuffisants et donc des déficits en eau utile envoyée en amont de ce Partiteur de Canneau. Cela impacte significativement le réseau d’irrigation aval, dont le CMRG. Nos travaux ont montré que la situation est d'autant plus critique que les débits eux-mêmes, en amont comme en aval du Partiteur, sont en fait très mal connus et devraient faire l'objet d'approches méthodologiques plus rigoureuses que celles déployées sur site actuellement.Aussi, face à ces constats, de nouvelles règles de distribution de l’eau s’imposent, pour continuer à irriguer et espérer obtenir un rendement agricole acceptable (souhaitable).Notre travail s'est ainsi donné pour objectif de contribuer à la mise en place des nouvelles règles de gestion de l’eau (répartition) au sein du réseau d’irrigation alimenté par le CMRG, pour continuer à fournir l’eau à l’irrigant en quantité acceptable (et connue). Cette amélioration de gestion a été envisagée à la fois en amont et en aval de ce réseau d’irrigation, particulièrement en ses différents nœuds-clés (Canal principal et Canal secondaire).La démarche méthodologique adoptée pour relever ce défi majeur s’appuie notamment sur un système d’information hydro-morpho-sédimentaire actualisé et de qualité. Il s’agit d’une base de données, riche en observations de hauteurs d’eau (lues aux stations limnimétriques), vitesses de surface au flotteur, champs de vitesse explorés au moyen d’un courantomètre et en données bathymétriques et granulométriques des tronçons des canaux étudiés, appréciées respectivement au moyen d’un GPS différentiel et du tamisage à sec.Les résultats fort encourageants obtenus permettent d'acquérir une meilleure compréhension du système et une amélioration particulière du réseau d’irrigation en rive gauche du Partiteur de Canneau. En s’appuyant sur les historiques de sédimentation du Lac-réservoir de Péligre (de 1960 à 2016), nous présentons un document de synthèse sur la sédimentation du Lac-réservoir de Péligre. Ce document met notamment en exergue le taux de sédimentation sévère de ce dernier (5.47 Mm3/an), qui continue d’augmenter encore aujourd’hui, ainsi que les conséquences de celui-ci sur les débits turbinés et la disponibilité de l’eau en amont du Partiteur de Canneau.Nous mettons également en évidence les formes irrégulières (Lit-non prismatique) des tronçons des canaux étudiés, via une vue axonométrique des profils en travers (issus de l’étude bathymétrique) des canaux d’irrigation en terre battue étudiés. Puis, nous présentons de manière détaillée le caractère très hétérogène des dépôts sédimentaires de ces derniers, à partir d’une analyse des représentations en Log-Probit des résultats du tamisage, construites au moyen du logiciel GrandPlots.En nous appuyant sur les mesures expérimentales des contraintes de Reynolds et des profils instantanés de vitesse (pris à intervalle de 64 ms), tirés de la base de données EPFL, nous avons montré qu’il faut absolument travailler dans les 18% inférieurs de la colonne d’eau (z/h<0.18) et en mode déficitaire, dans un écoulement turbulent comme celui-là, pour extraire de façon représentative et pertinente une pente expérimentale u*/, comme indicateur de u*.À l’issue d’un examen détaillé de la distribution verticale de la vitesse au canal secondaire FNE, nous validons un DMLWL (Dip-Modified-log-wake-law) à la fois en amont et en aval du réseau. Nous montrons que ceci permet de modéliser le Dip-phenomenon observé systématiquement au sein des profils explorés in situ. Nous proposons une relation entre le coefficient d’inégale répartition de la vitesse à la verticale αv (de Prony) et l’aspect ratio (W/h) pour tout le réseau d’irrigation étudié ;ceci afin d’obtenir une vitesse débitante (Ū), simplement à partir d’une prise de vitesse au flotteur, dans l’axe central d’écoulement.À partir des débits quantifiés à la section de référence du CMRG, via l’équation de continuité (Q=AŪ), nous fournissons un Abaque, diagramme à 3 entrées (débit (Qp), charge amont (H0) et ouverture de vanne (hv)), permettant aux vanniers de connaitre les débits au pont de fer correspondant aux différentes ouvertures de vanne et celui pour lequel le trop-plein (retour des eaux excédentaires vers le fleuve de l’Artibonite) commence à fonctionner.À l’égard des opérateurs locaux et gestionnaires du système, nous mettons enfin à disposition, des méthodes/outils simples et efficaces leur permettant de quantifier finement le débit au Canal principal en amont ainsi qu’au canal secondaire en aval, simplement à partir d’une mesure de hauteur d’eau (h) et de vitesse de surface au flotteur (Us).Doctorat en Sciences agronomiques et ingénierie biologique
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Nyman, Matthew W. "The interaction between chemical and mechanical processes during metamorphism : a microstructural and petrologic study of amphibolite shear zones, Cheyenne Belt, Southeastern Wyoming /." Diss., This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-10032007-171544/.
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Silva, Rafael Fernandes e. "O granito capão do leão: magmatismo Tipo-I altamente fracionado no sudeste do Cinturão Dom Feliciano, RS." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/133640.
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No SE do domínio oriental do Cinturão Dom Feliciano (CDF) o Granito Capão do Leão (GCL) ocorre como dois corpos, norte e sul, encaixados em rochas Pré-Cambrianas do Complexo Pinheiro Machado (CPM) e nos granitos Chasqueiro (GCH) e Arroio Grande (GAG). Os corpos do GCL, tanto o norte quanto o sul, possuem formas elípticas e ocupam áreas de, respectivamente, 200 km2 e 100 km2, apresentando orientação ENE-WSW, sendo dominantemente uma rocha maciça, a qual preserva suas características magmáticas. Zonas centimétricas a métricas de deformação dúctil, principalmente no corpo sul, são observadas gerando rochas miloníticas subverticais, apresentando plano de foliação com mergulho maior que 70° e direção NE-SW que podem refletir reativações da Zona de Cisalhamento Arroio Grande (ZCAG). Petrograficamente é um granito equigranular, médio a grosso, com textura hipidiomórfica predominante, de composição sieno a monzogranítica, apresentando, por vezes, cavidades miarolíticas centimétricas, as quais sugerem um posicionamento final em condições rasas (epizonal) e indicam a presença de fluidos até os estágios finais da cristalização, além de raros enclaves máficos, de composição micácea, os quais podem representar um material de origem mantélica fonte do granito, uma rocha encaixante fundida e assimilada pelo magma ou a ocorrência de uma mistura de magmas. Apresenta injeções centimétricas de veios ou bolsões tardios de aplitos. A assembleia mineral do GCL é constituída de quartzo, feldspato alcalino e plagioclásio do tipo albita. Como varietais ocorrem biotitas, dos tipos siderofilita e anita, granadas, com predomínio de membros finais em almandina e espessartina, e, subordinadamente, anfibólio cálcico do tipo ferro-pargasita. Seus minerais acessórios são apatita, titanita, zircão e opacos. O GCL é uma rocha de composição ácida, tem afinidade geoquímica subalcalina, metaluminosa a fracamente peraluminosa, com tendência cálcio-alcalina alto-K, apresentando elevados teores de SiO2, entre 71,60 e 75,95 %, teores de Al2O3 entre 11,00 e 15,00 %, teores em álcalis elevados, com valores de Na2O oscilando entre 1,76 à 4,61 % e 3,8 até 7,36 % para o K2O, baixos teores em CaO, MgO e MnO, menores que 1% e teores extremamente baixos de P2O5, menores que 0,03 %. A ocorrência de granada sugere um caráter altamente diferenciado, decorrente de longa cristalização fracionada. Os diagramas multielementares mostram enriquecimento em Rb, Pb, Th, U e K, e depleção nos elementos Ba, Nb, Sr, P, Eu e Ti , assim como enriquecimento de ETR leves em relação aos ETR pesados e acentuada anomalia negativa em Ba, Sr, Ti e Eu. O GCL apresenta características de magmatismo tipo-I, com alto fracionamento, de ambiente pós-colisional, apresentando padrões geoquímicos semelhantes ao GCH, os quais permitem correlacioná-los como líquidos segregados de uma mesma fonte, diferenciados por mecanismos petrológicos, tais como assimilação de material encaixante e cristalização fracionada. O líquido magmático dos granitos Capão do Leão, Chasqueiro e Arroio Grande, podem ter sua gênese relacionada a eventos de movimentação da Zona de Cisalhamento Arroio Grande, a qual pode ter causado a fusão da base da crosta, por adição de material mantélico, sendo, portanto, a responsável tanto pelo processo de extração, colocação e da referida segregação dos líquidos do GCL e do GCH, como pela geração e emplaçamento do líquido do GAG.In the SE of the eastern domain of Dom Feliciano Belt (CDF) the Capão do Leão Granite (GCL) forms two bodies, northern and southern, embedded in Precambrian rocks of the Pinheiro Machado Complex (CPM), Chasqueiro Granite (GCH) and Arroio Grande Granite (GAG). The GCL bodies are elliptically shaped predominantly massive rocks, which preserve their magmatic features, and cover areas of respectively 200 km2 and 100 km2, with ENE-WSW orientation. Centimetric to metric ductile deformation zones, mainly in the south body, are observed causing sub-vertical mylonitic rocks, with foliation plan whose dip is greater than 70° and orientation is NE-SW, which may reflect reactivation of Arroio Grande Shear Zone (ZCAG). Petrographically it is an equigranular medium to large granite, predominantly hypidiomorphic consisting of sieno to monzogranitic, sometimes presenting miarolitic centimetric cavities, which suggest a final positioning in shallow conditions (epizonal) and indicate the presence of fluids to the final stages of crystallization, in addition to rare mafic micaceous enclaves, which may represent a mantle-originated and source of granite material, a molten host rock assimilated by magma or the occurrence of a mixture of magmas. The GCL presents centimetric injections of veins or late albite pockets. The mineral assembly of GCL consists of quartz, alkali feldspar and albite-rich plagioclase. Varieties also occur such as siderophyllite and annite types of biotites, garnets with a prevalence of end-members in almandine and spessartine and subordinate calcic type Fe-pargasite amphibole. Its accessory minerals are apatite, titanite, zircon and opaques. GCL is a rock with acid composition, has metaluminous to weakly peraluminous subalkaline geochemical affinity, with calc-alkaline high-K trend, with high SiO2 level, between 71.60 and 75.95 %, Al2O3 level between 11.00 and 15.00 %, high contents of alkalis, with Na2O values ranging from 1.76 to 4.61 % and 3.8 to 7.36 % and of K2O, low contents of CaO, MgO and MnO, below 1 % and extremely low levels of P2O5, lower than 0.03 %. The occurrence of garnet suggests a highly distinctive character as a result of long fractional crystallization. The multi-element diagrams show enrichment in Rb, Pb, Th, U and K, and depletion in Ba, Nb, Sr, P, Eu and Ti, as well as enrichment of light REE in comparison to heavy REE and a pronounced anomaly in Ba, Sr, Ti and Eu. GCL has I-type highly fractionated magmatism characteristics, from a post-collisional environment, presenting geochemical patterns similar to those of GCH, which allows a correlation between them as segregated liquids from the same source, differentiated by petrological mechanisms such as host rock material assimilation, and fractional crystallization. The magmatic liquid of Capão do Leão, Chasqueiro and Arroio Grande granites, may have its genesis related to the movement of Arroio Grande Shear Zone, which may have caused the lower crust to melt, by adding mantle material and, therefore, being responsible for both the extraction and placing processes and for the referred GCL and GCH's liquids segregation, as for the petrogenesis and emplacement of GAG's liquid.
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Ghoma, Mohamed I. "The Effect of Wall Jet Flow on Local Scour Hole." Thesis, University of Bradford, 2011. http://hdl.handle.net/10454/5501.
Full textAbstract:
This thesis reports on investigations carried out to study of the effect of horizontal wall jets on rough, fixed and mobile beds in open channel flow. Experimental tests were carried out, using fixed and mobile sediment beds. Computer simulation models for the flow within the jet and resulting sediment transport were developed and their results analysed in this study.
In the experimental phase, tests were carried out with both fixed and mobile sediment beds. The shape of the water surface, numerous point velocity measurements and measurements of the evolving scour hole shape were made. Detailed descriptions of the turbulent flow field over a fixed rough bed and for scour holes at equilibrium were obtained for a range of initial jet conditions. Fully turbulent, multiphase flow was modelled using the Fluent Computational Fluid Dynamics software. This was used to analyze the flow caused by a jet in a rectangle open-channel with a rough bed, and also the flow pattern in a channel with a local scour hole. The volume of fluid (VOF) multiphase method and K- model was used to model the fluid flow in both cases. The model predictions of velocity and shear stress were compared against experimental observations.
The experimental data was used to develop new empirical relationships to describe the pattern of boundary shear stress caused by a wall jet over fixed beds and in equilibrium scour holes. These relationships were linked with existing bed-load transport rate models in order to predict the temporal evolution of scour holes. An analytical model describing the relationship between the wall jet flow and the development of a local scour hole shape was reported and its predictions compared with experimental data.
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Shen, Sophie [Verfasser], and Ingo [Akademischer Betreuer] Borggräfe. "Lokalisation von interiktalen epilepsietypischen Potentialen und Anfallsmustern bei pädiatrischen Epilepsiepatienten mit Läsionen in der cerebralen Magnetresonanztomographie / Sophie Shen ; Betreuer: Ingo Borggräfe." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2021. http://d-nb.info/1235325962/34.
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