This thesis compares pottery from Ike's Cut, Inagua, Bahamas with assemblages from the site of El Mango, Cuba, analyzed by Ashley Brooke Persons and the site of Ft. Liberte, Haiti, analyzed by Irving Rouse. The Ike's Cut site was a seasonally occupied location on the largest bank on Inagua, and was utilized for its access to marine resources. The migrants living here brought with them Meillacoid ceramics that were manufactured somewhere in the Greater Antilles. The objective of this research was to evaluate whether the ceramics at Ike's Cut share more in common with either the Hispaniolan or Cuban assemblages. These similarities can provide evidence from where these people came. Noting the frequency of certain traits in the distribution allowed me to draw conclusions regarding the similarities and differences in pottery characteristics among these Taíno sites. Upon completing a comparison of decorative modes and an analysis of rim types, I was able to conclude that these sites showed considerable similarities despite being situated in different regions. These results indicate the differences in site purposes and their corresponding ceramics, and also shed light on the continuity between decorative motifs throughout Taíno sites and the Caribbean. This indicates that Rouse’s initial hypothesis, that migration throughout these islands was unilateral, was false and that there was significant interaction between these three sites over time.

No description available.

Yes / This paper reviews existing studies relating to the assessment of sediment concentration profiles within various flow conditions due to their importance in representing pollutant propagation. The effects of sediment particle size, flow depth, and velocity were considered, as well as the eddy viscosity and Rouse number influence on the drag of the particle. It is also widely considered that there is a minimum threshold velocity required to increase sediment concentration within a flow above the washload. The bursting effect has also been investigated within this review, in which it presents the mechanism for sediment to be entrained within the flow at low average velocities. A review of the existing state-of-the-art literature has shown there are many variables to consider, i.e., particle density, flow velocity, and turbulence, when assessing the suspended sediment characteristics within flow; this outcome further evidences the complexity of suspended sediment transport modelling.

Mud makes up a large fraction of sediment transported within rivers to the coasts. Predicting where mud will settle is complicated by the cohesive nature of silts and clays, which can combine to form larger aggregates known as flocs. The size and density, and consequently, the settling velocity, of flocs is highly dynamic and depends on factors such as turbulence levels within the flow and biogeochemical components of the water and sediment. To better predict where mud will deposit, more observations of flocs while in their natural environment is required to better understand the controls on when, where, and to what degree mud is flocculated. However, the need for more field observations is complicated by the dynamic and fragile nature of flocs. This necessitates the need for developing in-situ observation methods to ensure that measured floc sizes are representative of their in-situ size, and not a result of sampling methods. In this thesis, a new instrument for in-situ observation of flocs is presented. In addition, two methods using the data collected from the instrument allow the user to: (1) identify sand within the particle data using a machine learning algorithm, and (2) estimate the mass suspended sediment concentration of the mud and sand fractions of suspended sediment independently. Results from using the instrument in the lowermost Mississippi River reveal differences in floc sizes over the water column, and by season. In addition, a unique observation of flocs in the presence of a salt wedge is presented. Overall, the instrument provided the first known observations of flocs within the Mississippi River, and provides a start to better understanding controls on floc sizes within the fluvial environment. / Master of Science / Flowing water within large rivers carries sediments such as sand and mud to the coasts. Some of the larger sediment carried by rivers can fall to the riverbed if the river does not have enough energy to carry it in the flow. The remaining sediment can be carried to the coasts where it will fall to the bed, providing the material necessary for estuaries or deltas to form and grow. Understanding when and where sediment falls to the bed within rivers, estuaries, and deltas, allows scientists and engineers to predict how these landforms will change over time to better manage them under future climate conditions. Predicting where mud will fall to the bed is particularly difficult because mud has the ability to stick together to form larger aggregates. These aggregates, known as mud flocs, are constantly changing in size depending on the energy in the river and water conditions. As the mud flocs change in size, the speed at which they fall to the bed changes. As such, observing mud flocs while they are in their natural environment is required to understand the conditions under which they form and change in size. This thesis presents a new instrument that can be used to collect images of mud flocs while they are in their natural environment. Results from using the instrument to observe mud flocs in the lowermost Mississippi River are then presented. This new instrument, and observations of mud flocs made with it, provides new insight into mud floc size within the lowermost Mississippi River.

À l'approche de la transition vitreuse les fondus de polymères montrent une augmentation importante de la viscosité de plusieurs ordres de grandeur. Le but de cette étude est d'acquérir une compréhension plus profonde des propriétés viscoélastiques des fondus de polymères vitrifiables. Les polymères sont modélisés comme des chaînes flexibles en utilisant un modèle de bille-ressort. Les propriétés dynamiques sont analysées dans le cadre de la théorie de couplage de mode idéale. Nous constatons que la température critique de couplage de mode varie avec l'inverse de la longueur de chaîne. En étudiant la fonction de relaxation de cisaillement, nous constatons que les processus de relaxation polymériques, ne sont pas modifiés, mais décalés vers des temps plus importants en approchant la transition vitreuse. / Polymer melts show a remarkable increase of their viscosity by many orders of magnitude on approaching the glass transition. The aim of this study is to gain a deeper insight into the viscoelastic properties of glass forming polymer melts. The polymers are modeled as flexible chains using a bead-spring model. The dynamic properties are analyzed in the framework of the ideal mode-coupling theory. We find that the critical temperature of the ideal mode-coupling theory scales with the reciprocal chain length. By studying the shear relaxation function we find that the polymer relaxation processes are not altered but shifted to later times in the approach of the glass transition.

La transition sol-gel des gels polymères traduit le passage d'une phase liquide (sol) à une phase solide (gel). Les propriétés statiques de tels gels semblent être correctement décrites par la théorie de percolation ; en revanche, les propriétés viscoélastiques présentent une grande variété de comportements à la transition sol-gel. Pour étudier l'influence de la structure chimique des précurseurs sur les propriétés dynamiques des polymères à la transition sol-gel, nous avons synthétisé deux systèmes polydiméthylsiloxanes (PDMS). Nos premiers résultats tendent à montrer que la structure chimique du réticulant n'influe pas sur les exposants critiques caractérisant la transition sol-gel. Après confrontation de nos résultats à ceux de la littérature, l'interprétation que nous proposons met en évidence deux transitions définissant ainsi trois domaines de comportement. Le mécanisme de percolation des gels PDMS semble être déterminé par le rapport du nombre de segments de Kuhn entre points de branchement sur celui entre enchevêtrements. Dans le but d'étudier le comportement dynamique de tels gels aux hautes fréquences, nous avons développé une méthode de caractérisation ultrasonore. Cette méthode, couplée à une méthode rhéologique classique, a permis la caractérisation sur une large gamme de fréquences d'un matériau viscoélastique étalon, le miel.

No description available.

La transition sol-gel des gels polymères traduit le passage d'une phase liquide (sol) à une phase solide (gel). Les propriétés statiques de tels gels semblent être correctement décrites par la théorie de percolation ; en revanche, les propriétés viscoélastiques présentent une grande variété de comportements à la transition sol-gel. Pour étudier l'influence de la structure chimique des précurseurs sur les propriétés dynamiques des polymères à la transition sol-gel, nous avons synthétisé deux systèmes polydiméthylsiloxanes (PDMS). Nos premiers résultats tendent à montrer que la structure chimique du réticulant n'influe pas sur les exposants critiques caractérisant la transition sol-gel. Après confrontation de nos résultats à ceux de la littérature, l'interprétation que nous proposons met en évidence deux transitions définissant ainsi trois domaines de comportement. Le mécanisme de percolation des gels PDMS semble être déterminé par le rapport du nombre de segments de Kuhn entre points de branchement sur celui entre enchevêtrements. Dans le but d'étudier le comportement dynamique de tels gels aux hautes fréquences, nous avons développé une méthode de caractérisation ultrasonore. Cette méthode, couplée à une méthode rhéologique classique, a permis la caractérisation sur une large gamme de fréquences d'un matériau viscoélastique étalon, le miel.

No description available.

Yes / The transfer of suspended sediment can range widely from being diluted to being hyperconcentrated, depending on the local flow and ground conditions. Using the Rouse model and the Kundu and Ghoshal (2017) model, it is possible to look at the sediment distribution for a range of hyper-concentrated and diluted flows. According to the Kundu and Ghoshal model, the sediment flow follows a linear profile for the hyper-concentrated flow regime and a power law applies for the dilute concentrated flow regime. This paper describes these models and how the Kundu and Ghoshal parameters (linear-law coefficients and power-law coefficients) are dependent on sediment flow parameters using machine-learning techniques. The machine-learning models used are XGboost Classifier, Linear Regressor (Ridge), Linear Regressor (Bayesian), K Nearest Neighbours, Decision Tree Regressor, and Support Vector Machines (Regressor). The models were implemented on Google Colab and the models have been applied to determine the relationship between every Kundu and Ghoshal parameter with each sediment flow parameter (mean concentration, Rouse number, and size parameter) for both a linear profile and a power-law profile. The models correctly calculated the suspended sediment profile for a range of flow conditions ( 0.268 𝑚𝑚𝑚𝑚 ≤ 𝑑𝑑50 ≤ 2.29 𝑚𝑚𝑚𝑚, 0.00105 𝑔𝑔 𝑚𝑚𝑚𝑚3 ≤ particle density ≤ 2.65 𝑔𝑔 𝑚𝑚𝑚𝑚3 , 0.197 𝑚𝑚𝑚𝑚 𝑠𝑠 ≤ 𝑣𝑣𝑠𝑠 ≤ 96 𝑚𝑚𝑚𝑚 𝑠𝑠 , 7.16 𝑚𝑚𝑚𝑚 𝑠𝑠 ≤ 𝑢𝑢∗ ≤ 63.3 𝑚𝑚𝑚𝑚 𝑠𝑠 , 0.00042 ≤ 𝑐𝑐̅≤ 0.54), including a range of Rouse numbers (0.0076 ≤ 𝑃𝑃 ≤ 23.5). The models showed particularly good accuracy for testing at low and extremely high concentrations for type I to III profiles.