Previous studies have shown that the continental shelf and slope area off northeastern Taiwan is a region where the material exchange processes between the East China Sea and open ocean are most rigorous under the influences of the Kuroshio and the monsoons. In order to understand the topographic effects on the particulate flux and the transport path of the settling particles in this region, this study has conducted a series of field measurements using time-series sediment traps and current meters as tools. The temporal and spatial variations on the current, the particulate flux and the particle-size distribution as well as the activity and flux of 210 Pb and 210 Po are presented in this thesis. The biological productivity and the runoff of main rivers from Taiwan were not correlated with the particulate fluxes in our study area. However, the variations of the particulate flux in the canyon and on the slope areas were clearly affected by the tidal currents, showing good positive correlation with their amplitudes. The particulate, 210 Pb and 210 Po fluxes all showed an increase toward the ocean bottom but a decrease away from the shore, suggesting that the transports of particle and particle reactive elements were strongly influenced by the lateral transport process in the study area. Highest fluxes were observed in the Mien-Hua Canyon(MHC) and the lower slope southwest of the canyon. Intermediate values were observed in the South Okinawa Trough and the North Mien-Hua Canyon(NMHC). The intercanyon slope and the shallow traps in the NMHC had lowest values. The particulates and particle reactive elements were transported out of the shelf or upper slope area essentially through the MHC toward the slope southwest of the canyon. The NMHC and the intercanyon area were not major pathways for these materials. The fluxes of particle, 210 Pb and 210 Po in the study area were generally at least an order of magnitude greater than those observed from other continental margins in the world, except for the lowest values at the intercanyon station and the shallow water in the NMHC. Thus the continental margin off northeastern Taiwan is one of the most important areas for material exchanges with open oceans in the world. The trapped particulates were mainly silt with variable sand fractions. High sand contents were observed in the MHC and the lower slope southwest of the canyon, the intermediate values were in the outlet of the MHC and the NMHC, and the lowest in the South Okinawa Trough. This shows that the sand content decreases awayfrom the shore. On the contrary, silt and clay fractions in percent increase away from the shore. Under the influence of tidal currents, the settling sand particles in the MHC and its adjacent lower slope were laterally transported from resuspended sandy sediments of the continental shelf and upper slope area adjoining the head of the MHC. The fluxes of sand, silt and clay all decreased toward the South Okinawa Trough but increased toward the bottom. This particle-size distribution pattern also reflected the effect of lateral transport process in the study area. Variations of the 210 Pb activity in this study area were generally correlated inversely with the particulate flux and the sand content, indicating the effect of dilution of the mass flux and the sand content, but were positively correlated with the silt and clay contents because they were major 210 Pb scavengers. No apparent correlations of 210 Po with the mass flux and the three particle-size fractions were observed, suggesting that the variation of 210 Po activity was not related to the mass fluxes or the three particle-size fractions. High 210 Pb activities were found to be associated with high contents of POC, Mn and Fe. Correlations of 210 Pb with both Mn and Fe indicate that the oxide and hydroxide precipitates of Mn and Fe supplied from sediments on the continental shelf, upper slope area and submarine hydrothermal activities might serve as important mechanisms for enhanced 210 Pb scavenging. The relationship between the 210 Pb activity and the POC content might reflect either the settling mode of the fine particles incorporated with fecal pellets or aggregates, or sharing the same source with fine particles. The variatio ns of 210 Po activity were not correlated with Mn, Fe, major components or biogenic components, implying that the association of 210 Po with biogenic components might be masked by the enormous terrigenous materials. Except for the upper-trap samples collected at the intercanyon slope and the NMHC, the 210 Po activity was lower than the 210 Pb activity with 210 Po/210 Pb ratios less than unity. Based on comparisons of 210 Pb and 210 Po with relevant parameters and references of past studies, we can propose several possible mechanisms to explain why the ratios were less then unity: 1. 210 Pb was preferentially scavenged by advecting and settling particulates of terrigenous origin. 210 Po, known to be biophilic, might remain associated with the suspended organic particulates which could be dissolved or not settling. Moreover, the oxide and hydroxide precipitates of Mn and Fe in the study area would further enhance the scavenging of 210 Pb. 2. The particulates in suspension were favorable for differentiation between 210 Pb and 210 Ponuclides while those settled in sediments would allow them to grow toward the secular equilibrium. Therefore, the trapped particulates might be in frequent suspension and short in deposited sediments during their lateral transport. 3. The 210 Pb supplied from the East Asia aerosol in large quantity was accumulated in water column abd carried by the Kuroshio to the study area. The intrusion and eddies of Kuroshio off northeastern Taiwan could bring large amount of 210 Pb into the region of continental shelf and slope, allowing particulates to scavenge 210 Pb more effectively from the surrounding water. The upper trap in the NMHC and that in the intercanyon site yield lowest particulate flux but highest POC content. With less terrigenous material and more biogenic components in these samples, 210 Po/210 Pb ratios were greater than unity and variations of 210 Pb activity were hardly correlated with those of POC contents but were inversely correlated with those of Mn contents. However, the 210 Po activities of upper trap at the intercanyon site were well positively correlated with POC and PIC contents, indicating effects of the fresh biogenic particles. Based on the mass balance calculations of particulate and 210 Pb fluxes, current data and other related data gathered in this study, we may infer the sedimentation dynamics and transport path of the settling particles below 300m depth in the study area. Under the influence of tidal oscillation, terrigenous sediments on the shelf and the shelf break as well as the upper slope would be resuspended and carried into the MHC and transported further away. Most of the sand particles would deposit in the canyon while part of the silt and clay would be transported to the South Okinawa Trough directly and the rest to the lower slope southwest of the MHC. The particulate flux at the lower slope southwest of MHC might also have a portion of particulates swept from the upper slope by the Kuroshio eddies. As the NMHC and the intercanyon sites are located in the central area of the Kuroshio eddies, the particulates from the continental shelf and upper slope area would be blocked, resulting in very low particulate fluxes. High particulate fluxes observed in the lower NMHC trap should largely be due to resuspension of the sediments from the banks of the canyon.

Sedimentation rates in sediment cores from Lavaca Bay have been high within the last 1-2 decays within the central portion of the bay, with small fluctuations from river input. Lavaca Bay is a broad, flat, and shallow (<3 m) microtidal estuary within the upper Matagorda Bay system. Marine derived sediment enters the system from Matagorda Bay, while two major rivers (Lavaca & Navidad) supply the majority of terrestrially derived sediment. With continuous sediment supply the bay showed no bathymetric change until the introduction of the shipping channel. Processes that potentially lead to sediment transport and resuspension within the bay include wind driven wave resuspension, storm surges, wind driven blowouts, and river flooding. These processes were assessed using X-radiographs, grain size profiles, and 210Pb and 137Cs geochronology of sediment diver cores. In six cores the upper 10 cm of the seabed has been physically mixed, where as the rest showed a continuous sediment accumulation rate between 0.84-1.22 cm/yr. Sidescan sonar and subbottom chirp sonar data coupled with sedimentological core and grab samples were used to map the location and delineate the sedimentary facies within the estuarine system in depths >1 m. Five sedimentary facies were identified in Lavaca Bay and adjacent bays, they are: 1) estuarine mud; 2) fluvial sand; 3) beach sand; 4) bay mouth sand; and 5) oyster biofacies. Of the five facies, Lavaca Bay consists primarily of estuarine mud (68%). Pre-Hurricane and post-Hurricane Claudette cores were obtained to observe the impact to the sedimentary processes. The north and south Lavaca Bay were eroded by 10 cm and 2-3 cm, respectively. Cox Bay and Keller Bay saw a net deposition of 2-3 cm.

Der Bericht beschreibt die Arbeiten zur CFD-Modellentwicklung zur Beschreibung des Fasertransportes in einer Wasserströmung, die im Unterauftrag der Hochschule Zittau/Görlitz erfolgten. Während die experimentellen Arbeiten zu dieser Thematik in Zittau durchgeführt wurden, lag der Schwerpunkt der theoretischen Arbeiten in Rossendorf. Im Arbeitspunkt EZ 1 des Projektantrages ist die Erweiterung der Einzeleffektuntersuchungen vorgesehen. Die entsprechenden Modellansätze zum Partikeltransport sind im Kapitel 3.1. beschrieben. Die Modellanpassung und Validierung ist in 3.2 und 3.3 dargestellt. Der Fasertransport in einer Wasserströmung wird durch Jet-Phänomene bestimmt. Untersuchungen dazu sind im EZ3.1 des Projektantrages: 3D-Phänomene infolge Blasenmitriss vorgesehen und die Modellansätze und der Vergleich zu Experimenten in den Kapiteln 4.1 bis 4.3 dargestellt. Des Weiteren wird der Einfluss auf den Ausgleich der Temperatur für den Fall untersucht, dass der Jet kälter als die Wasservorlage im Tank ist. Dieser Abschnitt entspricht damit der EZ3.2 des Antrages: 3D-Phänomene infolge Temperaturdifferenzen. Im Kapitel 4.4 wird auf die Strömungsvorgänge in der Zittauer Strömungswanne eingegangen und damit der Punkt EZ4 des Antrages: Integraluntersuchungen bearbeitet. Kapitel 5 beschreibt die Entwicklung eines Sieb-Modells, das die Faser-Kompaktierung berücksichtigt und auf der Darcy-Gleichung basiert. Die Modellparameter werden an Experimenten in Zittau justiert. Diese Experimente wurden für verschiedene Materialien durchgeführt und mit deren Hilfe ein Koeffizientenkatalog erstellt. Das Modell wurde in den CFD-Code CFX implementiert und anhand einiger Anwendungsbeispiele demonstriert.

Die CFD-Modellierung des Fasertransports wurde auf der Basis des Euler/Euler-Ansatzes untersucht. Die Nachbildung des Transportverhaltens der Partikel erfordert die korrekte Beschreibung des Impulsaustausches. Hierfür liefert die Auswertung der Sinkgeschwindigkeiten aus den Experimenten am Versuchsstand "Säule" die notwendigen Informationen. Über die Vorgabe von Partikeldichte und Partikeldurchmesser kann die Sinkgeschwindigkeit nachgebildet und der Partikeltransport adäquat modelliert werden. Beispielsimulationen einer partikelbeladenen Strömung im Versuchsstand "Ringkanal" lieferten plausible Resultate. Das Anlagerungs- bzw. Abtragungsverhalten der Partikel an Hindernissen (z. B. Wehren) wurde über die Modellierung einer vom Feststoffanteil abhängigen Viskosität simuliert. Dieser Zusammenhang wurde an die Ergebnisse der Experimente im Ringkanal angepasst. Erste Demonstrationsrechnungen zur Beschreibung des Partikeltransportes an Hindernissen ergaben plausible Resultate. In anderen Beispielen zeigte die Parametervariation einer feststoffabhängigen Viskosität jedoch einen zu geringen Einfluss auf die berechneten Ablagerungsmengen, um die experimentellen Befunde zu reproduzieren. Es wurde ein Modell des Differenzdruckaufbaus aus den Kompaktierungseigenschaften der auf dem Sieb abgelagerten Fasern entwickelt und an Experimenten justiert. Damit steht neben den in der Literatur veröffentlichten Korrelationen ein weiteres Verfahren zur Berechnung des Differenzdrucks zur Verfügung. In einer Machbarkeitsstudie wurde die Wirkung eines Siebes auf das Strömungsfeld unter Nutzung des Modellansatzes des porösen Körpers in CFX-4.4 implementiert. Das implementierte Modell liefert qualitativ plausible Resultate.

Thesis (M.S.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains ix, 132 p. : ill. (some col.), maps (some col.). Includes abstract. Includes bibliographical references (p. 106-109).

Thesis (M.S.)--Rutgers University, 2009. / "Graduate Program in Geological Sciences." Includes bibliographical references (p. 45-51).

Thesis (M. Sc.)--University of Canterbury, 2009. / Typescript (photocopy). Includes bibliographical references (leaves 84-94). Also available via the World Wide Web.

Thesis (M.A.)--University of Texas at Austin, 1988. / Vita. Includes bibliographical references (leaves 116-124).

Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 401-431). Available also in a digital version from Dissertation Abstracts.

Thesis (Ph. D.)--University of North Texas, May, 2008. / Title from title page display. Includes bibliographical references.