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231	Modellierung und Simulation der Beanspruchung von Zugsträngen aus Stahllitze für Zahnriemen / Load modelling and simulation of steelcords for timing belts Witt, Robert 11 September 2008 (has links) (PDF) In dieser Arbeit wird das Verhalten von gewickelten Seilen aus Stahllitze unter Zug- und Biegebelastung mit Hilfe der Methode der Finiten Elemente untersucht. Ausgehend von dem Modell einer einfachen Litze mit einem Kern- und sechs Außendrähten erfolgt eine ausführliche Analyse der Spannungsverteilung sowohl bei rein axialer Belastung als auch bei Biegung über eine Seilscheibe. Darauf aufbauend wird das Simulationsmodell schrittweise um komplexere Seilkonstruktionen bis hin zu zweifachen Verseilungen erweitert. Daran schließt sich die Untersuchung der inneren Belastungen bei Einbettung in ein Elastomer an, wie dies bei Zugsträngen in Riemengetrieben der Fall ist, sowie der spezifischen Einflüsse der Verzahnung auf die Seilbeanspruchung bei Zahnriemengetrieben. Des weiteren wird eine Möglichkeit der Validierung der Modelle vorgestellt, die ein experimentelles Ermitteln der Relativverschiebungen der Filamente auch im Inneren des Seils zulässt. Abschließend folgen Richtlinien zur Auslegung von Zugsträngen in Zahnriemen sowie Vorschläge, die in dieser Arbeit gewonnenen Ergebnisse in eine zukünftige Verschleißtheorie einfließen zu lassen. / This work examines the behaviour of steel cords under tensile loading and bending by the Method of Finite Elements (FEM). Beginning with a simple strand consisting of one centre and six outer wires a detailed analysis of the stress distribution is made for pure strain as well as for bending over a sheave. Based on this examination the model is extended step by step towards complex cord constructions. The investigation of cables embedded in an elastomer follows, especially the influence of a tooth profile of timing belts on the load inside the cable. Furthermore, a possible validation method for the model is presented. In conclusion directives are given for steel cord design in timing belts and suggestions are made to use the results in a wear model in the future. Seilbiegung Drahtseil Seilscheibe Biegewechsel FEM Zahnriemen Finite Elemente Methode Stahlseil Simulation Verschleiß bending strength wire rope steel cord steelcord sheave pulley bending fatigue reverse bending cycle flexing cycle FEM Finite Element Method timing belt driving belt synchronous belt tooth belt Simulation wear abrasion ddc:620 rvk:ZL 4130 rvk:ZO 1713
232	A geology field guide for secondary students visiting the Landels-Hills Big Creek Reserve, Big Sur, California Bohls, Carol Elaine 27 February 2012 (has links) A field guide is always a handy, but rare, little document, especially for a secondary educator. Therefore, the purpose of this project was to research, develop, write and present this document, for the Landels-Hill Big Creek Reserve. The University of California Natural Reserve System oversees thirty-six multi-acre, natural reserves. One part of the overall mission of these reserves is an educational outreach program in which curriculum is made available to the school systems. The curriculum is to be used to educate the students about each specific reserve area, to engage students in learning about their environment and to create an awareness of the need for conservation of wild areas. The final products from this research are a secondary-level geology guidebook, for students, with suggested classroom and in-field lessons, specifically written for the Landels-Hill Big Creek Reserve, Big Sur, California, along with a revised and updated geologic map of the Reserve and a teaching rock collection, for use at the Reserve. / text Big Creek Reserve Franciscan Coast Ridge Belt Student guidebook Big Creek conglomerate
233	Adaptation of locomotor control in able and impaired human walking Toney, Megan 21 September 2015 (has links) Extensive research has documented the stereotypical kinematic and kinetic patterns in healthy human walking, but we have a limited understanding of the neuromechanical control principles that contribute to their execution. Furthermore, the strategies used to adapt human walking to morphological or environmental constraints are poorly understood. After a traumatic injury, like amputation, regaining independent mobility is a primary goal of rehabilitation. Without a clear understanding of the neuromechanical principles governing locomotion, monitoring and quantitatively improving gait rehabilitation outcomes is challenging. The purpose of this doctoral work was to identify controlled variables in able and impaired human walking and to compare the control strategies used to adapt to a novel walking environment both with and without amputation. I apply an uncontrolled manifold (UCM) analysis to test whether likely goal variables of human walking are selectively stabilized through step-to-step variability structure. I found that both able-bodied subjects and subjects with an amputation maintain consistent whole body dynamics and leg power production by exploiting inherent motor abundance. Consistent leg power production is accomplished primarily through step-to-step leg force corrections that are driven by variable timing of ankle torque production. Covariance between ankle and knee torques enable robust motor control in able-bodied individuals, but this stabilizing mechanism is absent in individuals with a transtibial amputation. This coordinated joint torque control also appears to assist able-bodied short-term adaptation, invoked by split-belt treadmill walking. However, loss of ankle motor control and distal sensory feedback due to amputation appears to limit reactive, feedback driven adaptation patterns in subjects with an amputation. Ultimately, this work highlights the role of intact distal sensorimotor function in locomotor control and adaptation. The major findings I present have substantial implications for gait rehabilitation and prosthetic design. Biomechanics Locomotion Amputation Motor control Uncontrolled manifold Adaptation Split belt treadmill
234	THE INTEGRATION OF PHYSICAL ROCK PROPERTIES, MINERALOGY AND GEOCHEMISTRY FOR THE EXPLORATION OF LARGE HYPOGENE ZINC SILICATE DEPOSITS: A CASE STUDY OF THE VAZANTE ZINC DEPOSITS, MINAS GERAIS, BRAZIL MCGLADREY, ALEXANDRA JANE 27 March 2014 (has links) Exploration for large zinc silicate deposits is more challenging than zinc sulfide deposits, as they do not exhibit similar geophysical anomalies. The Vazante deposit, which is the world’s largest zinc silicate deposit, occurs in brecciated dolomite and comprises mainly willemite with various proportions of hematite, and minor franklinite and sphalerite. In the Vazante region, the exploration challenge is enhanced as outcrops are rare, bedrock generally sits below 10s of metres of laterite cover and barren hematite-rich breccias have a similar geophysical signature to willemite ore bodies. In order to evaluate the applications of geophysical surveys in the exploration of this type of deposit, data from 475 samples were investigated from drill holes representative of the various types of ore, host rocks and zones of known geophysical anomalies in the Vazante District. Geochemical (ICP-MS and XRF) and mineralogical (optical, EMPA, SEM and MLA) data were integrated with physical rock properties (density, magnetic susceptibility and K-U-Th gamma ray spectrometry) to assist in finding new ore zones. The most distinct physical property of the ore is density (3.0-4.3 g/cm3), compared with the host rocks (2.7-3.0 g/cm3). This is due to high proportion of denser minerals (hematite and willemite) in the ore. However, barren hematite breccias also have high densities (3.0-4.5 g/cm3). The zinc ore and hematite breccias yielded higher magnetic susceptibilities (0.1-38 x10-3 SI) than the surrounding host rocks, with the highest values associated with greater proportions of franklinite and magnetite (7-38 x10-3 SI). The zinc ore has an elevated U concentration (up to 33ppm) relative to the various host rocks (up to 7 ppm), yielding higher gamma spectrometric values. The results of this investigation indicate that an integration of magnetic, gravimetric and radiometric surveys would be required to identify zinc silicate ore zones and potentially differentiate them from barren hematite breccias and host rocks. / Thesis (Master, Geological Sciences & Geological Engineering) -- Queen's University, 2014-03-27 13:32:54.132 Gamma Ray Spectrometry Mineral Exploration Physical Rock Properties Brasilia Fold Belt Zinc Silicate Deposits
235	Impacts of Bubbles on Optical Estimates of Calcium Carbonate in the Great Calcite Belt Brown, Michael Scott 20 March 2014 (has links) In this MSc thesis I determine if wind-generated bubbles elevated measurements of above-water normalized water-leaving radiance (nLw) and subsequent remote sensing estimates of particulate inorganic carbon (PIC) in a coccolithophore bloom on the Patagonian Shelf. Although no measurements were made of bubbles, shipboard wind speed was used as a proxy for bubble backscattering. An empirical orthogonal function (EOF) analysis was performed on nLw. The first EOF accounted for 95% of the variance, and was attributed to changes in spectral amplitude. Scores of the first EOF were positively correlated with flow-through PIC backscattering (bb′) > 5x10-4 m-1, indicating that above this threshold PIC was an optically active seawater constituent. There was only evidence for a bubble elevation of nLw at values of bb′ < 5x10-4 m-1 and wind speeds > 12.5 m s-1. There was no evidence for a bubble elevation of PIC estimated using the two-band PIC algorithm. remote sensing bio-optics bubbles coccolithophores particulate inorganic carbon Great Calcite Belt Patagonian Shelf
236	Structural Geology and Geochronology of the Bernic Lake Area in the Bird River Greenstone Belt, Manitoba: Evidence for Syn-Deformational Emplacement of the Bernic Lake Pegmatite Group Kremer, Paul January 2010 (has links) The Bernic Lake Formation in the Bird River greenstone belt consists dominantly of mafic to felsic arc volcanic and volcaniclastic rocks, with varying amounts of mafic to felsic intrusive rocks, including the Bernic Lake pegmatite group. U-Pb geochronoligical analyses on selected samples around the Bernic Lake area, indicate that the Tanco gabbro, the Birse Lake granodiorite and the volcanic rocks of the Bernic Lake Formation are contemporaneous ca. 2724 Ma and form part of a singular volcanic and subvolcanic complex. The highly evolved, LCT-type, rare element-bearing Bernic Lake pegmatite group, including the world class Tanco pegmatite, was emplaced in the Bernic Lake Formation during a belt-scale tectonomagmatic event associated with G3 deformation between ca. 2650 and 2640 Ma. Early and rarely preserved isoclinal folding in the Bernic Lake Formation attributed to G1 deformation was followed north-south directed compression resulting in refolding and transposition of G1 structures by east-west trending upright F2 folds. Continued compression caused strain localization and south-side-up shearing along the North Bernic Lake Shear Zone (NBLSZ), which juxtaposes MORB-like basalt of the south panel to the south against arc rocks of the Bernic Lake Formation to the north. G3 deformation is characterized by a spaced S3 fracture cleavage that overprints the penetrative S2 fabric, and dextral reactivation of the NBLSZ. Pegmatitic melt ascended from depth along the reactivated NBLSZ during this time and was emplaced both within the shear zone and within rock units adjacent to it. The shapes and orientations of the pegmatites are controlled in part by the rheology of the host rocks into which they were emplaced. Rheologically competent lithologies responded to G3 strain by brittle fracture and the pegmatites occurring therein are flat and tabular; rheologically incompetent lithologies responded to G3 strain by ductile-brittle deformation and the pegmatites therein are irregular, folded, and/or boudinaged. The contrasting styles suggest that the pegmatites intruded while the rocks of the Bernic Lake Formation were at or near the brittle-ductile transition. Pegmatite emplacement Bird River greenstone belt Tanco pegmatite Bernic Lake geochronology Earth Sciences
237	The Timing and Causes of Illite Formation in the Cretaceous Marias River Shale, Disturbed Belt, Montana Osborn, Stephen Gerard 09 June 2006 (has links) The clay mineralogy data and K-Ar ages of I/S measured in this study agree with previous work conducted within the Disturbed Belt (Hoffman, 1976) and show that diagenetic I/S formed quickly at several different places in response to thrust sheet burial during the Laramide orogeny. The averages of concordant age values for clay sub-fractions separated from three bentonites of Cretaceous and Jurassic depositional age increase from southeast (53.6 Ma) to northwest (56.7 Ma) along the trend of the Disturbed Belt. This northwestward increase of mean ages of I/S is consistent with a thrust sheet emplacement model for the Disturbed Belt (Mudge and Earhart, 1980). The rate of the eastward advancement of the Lewis Thrust Sheet derived from the concordant K-Ar dates of I/S was about 1 cm/year in the Marias River area. The absence of the 2M1 illite polytype in most bentonitic shales does not permit the derivation of the age of diagenetic I/S by Illite Age Analysis and yet constrains the estimate of maximum burial temperature to 250°C. Chemical remanent magnetization Disturbed Belt Montana K-Ar illite Geography Geology
238	TECTONOMETAMORPHIC EVOLUTION OF THE KIOSK DOMAIN, CENTRAL GNEISS BELT, GRENVILLE PROVINCE, ONTARIO: CONSTRAINTS FROM GEOCHRONOLOGY AND THERMOBAROMETRY Foster, John Gordon Joseph 20 July 2012 (has links) The Kiosk domain in the Central Gneiss Belt, southwestern Grenville Province, Ontario comprises ca.1655 Ma orthogneisses and volumetrically minor ca. 1480-1460 Ma parag- neisses that were affected by granulite-facies metamorphism between ca. 1480 and ca. 1000 Ma. The objectives of this study are: (i) to determine the protolith ages from the Kiosk domain and the underlying southern Bonfield Batholith; (ii) to determine the tim- ing of major tectonic episodes; (iii) to determine the pressure-temperature conditions of peak metamorphism; and (iv) to use these data to constrain the position of the Allochthon Boundary Thrust in the southwestern Grenville Province. Grenville Province Geochronology Central Gneiss Belt Thermobarometry Zircon Monazite Kiosk domain
239	Large Scale ULF Waves and Energetic Particles in the Earth's Magnetosphere Lee, Eun Ah Unknown Date No description available. Pc 5 ULF Waves Energetic Particles Radiation Belt Magnetosphere Geomagnetic Storms
240	Rethinking ecofeminism : Wangari Maathai and the Green Belt Movement in Kenya. Muthuki, Janet Muthoni. January 2006 (has links) Issues of the environment have received increasing attention as demonstrated by the rise of the ecological movement in response to the threat of overpopulation, intensive agricultural methods and chemical pollution, all of which are reinforced by industrialization. Ecofeminist theories assert that industrialisation and capitalism have resulted in the oppression of both women and nature. Ecofeminism therefore represents a critique of patriarchal frameworks as well as a grassroots political movement with strategies to bring about an ecological revolution. However, ecofeminism as articulated in the West has been criticised for homogenizing and essentialising women. This study conceives ecofeminism from an African perspective by examining the work of Maathai and her Green Belt Movement (GBM) in relation to the Kenyan context. The study examines the effect of hegemonic practices such as colonialism and capitalism on the environment and gender relations. The study motivates the argument that Maathai's GBM offers a critique of industrialism and capitalist patriarchy occasioned by colonialism as well as a response to sustainability. The study advances the argument that the GBM represents a rethinking of the homogenizing imperative of western ecofeminism. The central hypothesis of this article is that Wangari Maathai's GBM is an African ecofeminist activism, which through environmental issues and interventions highlights gender relations and challenges patriarchy within national and global ideological structures. / Thesis (M.Soc.Sci.)-University of Kwazulu-Natal, 2006. Ecofeminism. Agroforestry--Kenya. Theses--Gender studies. Green Belt Movement (Society : Kenya)

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