Doctor of Philosophy

dissertationStimuli-responsive hydrogels are called "smart" materials because they autonomously respond to environmental stimuli. For example, pH-responsive hydrogels swell at lower pH levels and deswell as the pH increases. Hydrogel-based sensors could prove beneficial for providing continuous monitoring of bioreactors. The motivation of this project is to create a hydrogel-based sensor that can be used for bioreactor monitoring to help researchers monitor bioreactor conditions. The magnitude of the swelling/deswelling behavior can be measured by placing a sample of the hydrogel in a piezoresistive sensor. The degree of swelling/deswelling is directly proportional to the change in pH of the aqueous solution in which it is placed. In this project, an initial characterization of the hydrogel response was performed, followed by an analysis of the hydrogel components and optimization of the hydrogel response based on those components. The longevity of the hydrogel response was tested in terms of shelf life and response after multicycle testing. A hydrogel sample was then synthesized in situ in a microsensor and tested to determine the ability to transport hydrogels and how the miniaturization of the sensor may affect the stimuli response. In all experiments, the response time and magnitude results were compared to determine the effect of the noted changes on the kinetics of the swelling behavior of the material in order to find the optimal composition, thickness, and device specifications that will yield the desired response time and sensitivity

Snug Harbor

Snug Harbor is a collection of poetry dealing with a collective working history and the personal working history of growing up in various restaurants around Upstate New York

A near real-time algorithm for flood detection in urban and rural areas using high resolution Synthetic Aperture Radar images

A near real-time flood detection algorithm giving a synoptic overview of the extent of flooding in both urban and rural areas, and capable of working during night-time and day-time even if cloud was present, could be a useful tool for operational flood relief management and flood forecasting. The paper describes an automatic algorithm using high resolution Synthetic Aperture Radar (SAR) satellite data that assumes that high resolution topographic height data are available for at least the urban areas of the scene, in order that a SAR simulator may be used to estimate areas of radar shadow and layover. The algorithm proved capable of detecting flooding in rural areas using TerraSAR-X with good accuracy, and in urban areas with reasonable accuracy

Near real-time flood detection in urban and rural areas using high resolution Synthetic Aperture Radar images

A near real-time flood detection algorithm giving a synoptic overview of the extent of flooding in both urban and rural areas, and capable of working during night-time and day-time even if cloud was present, could be a useful tool for operational flood relief management. The paper describes an automatic algorithm using high resolution Synthetic Aperture Radar (SAR) satellite data that builds on existing approaches, including the use of image segmentation techniques prior to object classification to cope with the very large number of pixels in these scenes. Flood detection in urban areas is guided by the flood extent derived in adjacent rural areas. The algorithm assumes that high resolution topographic height data are available for at least the urban areas of the scene, in order that a SAR simulator may be used to estimate areas of radar shadow and layover. The algorithm proved capable of detecting flooding in rural areas using TerraSAR-X with good accuracy, classifying 89% of flooded pixels correctly, with an associated false positive rate of 6%. Of the urban water pixels visible to TerraSAR-X, 75% were correctly detected, with a false positive rate of 24%. If all urban water pixels were considered, including those in shadow and layover regions, these figures fell to 57% and 18% respectively

Lost Decades: Lessons from Post-Independence Latin America for Today's Africa

Africa and Latin America secured their independence from European colonial rule a century and half apart: most of Latin America after 1820 and most of Africa after 1960. Despite the distance in time and space, they share important similarities. In each case independence was followed by political instability, violent conflict and economic stagnation lasting for about a half-century (lost decades). The parallels suggest that Africa might be exiting from a period of post-imperial collapse and entering a period of relative political stability and economic growth, as did Latin America a century and a half earlier.

An improved subgrid channel model with upwind form artificial diffusion for river hydrodynamics and floodplain inundation simulation

An accurate estimation of river channel conveyance capacity and the water exchange at the river-floodplain interfaces is pivotal for flood modelling. However, in large-scale models limited grid resolution often means that small-scale river channel features cannot be well represented in traditional 1D/2D schemes. As a result instability over river and floodplain boundaries can occur, and flow connectivity, which has a strong control on the floodplain hydraulics, is not well-approximated. A subgrid channel model (SGC) based on the local inertial form of the shallow water equations, which allows utilization of approximated sub-grid scale bathymetric information while performing very efficient computations has been proposed as a solution, and it has been widely applied to calculate the wetting and drying dynamics in river-floodplain systems at regional scales. Unfortunately, SGC approaches to date have not included latest developments in numerical solutions of the local inertial equations, and the original solution scheme was reported to suffer from numerical instability in low friction regions such as urban areas. In this paper, for the first time, we implement a newly developed diffusion and explicit adaptive weighting factor in the SGC model. An adaptive artificial diffusion is explicitly included in the form of an upwind solution scheme based on the local flow status to improve the numerical flux estimation. A structured sequence of numerical experiments is performed, and the results confirm that the new SGC model improved the model performance in terms of water level and inundation extent, especially in urban areas where the Manning parameter is less than 0.03 m&minus;1/3 s. By not compromising computational efficiency, this improved SGC model is a compelling alternative for river-floodplain modelling, particularly in large-scale applications.</p

Testing the impact of direct and indirect flood warnings on population behaviour using an agent-based model

This paper uses a coupled hydrodynamic agent-based model (HABM) to investigate the effect of direct or indirect warnings in flood incident response. This model uses the LISFLOOD-FP hydrodynamic model and the NetLogo agent-based framework and is applied to the 2005 flood event in Carlisle, UK. The hydrodynamic model provides a realistic simulation of detailed flood dynamics through the event, whilst the agent-based model component enables simulation and analysis of the complex, in-event social response. NetLogo enables alternative probabilistic daily routine and agent choice scenarios for the individuals of Carlisle to be simulated in a coupled fashion with the flood inundation. Specifically, experiments are conducted using a novel “enhanced social modelling component” based on the Bass diffusion model. From the analysis of these simulations, management stress points (predictable or otherwise) can be presented to those responsible for hazard management and post-event recovery. The results within this paper suggest that these stress points can be present, or amplified, due to a lack of preparedness or a lack of phased evacuation measures. Furthermore, the methods outlined here have the potential for application elsewhere to reduce the complexity and improve the effectiveness of flood incident management. The paper demonstrates the influence that emergent properties have on systematic vulnerability and risk from natural hazards in coupled socio-environmental systems

Lost Decades: Postindependence Performance in Latin America and Africa

Africa and Latin America secured independence from European colonial rule a century and half apart: most of Latin America by the 1820s and most of Africa by 1960. Despite the distance in time and space, they share important similarities. In each case independence was followed by political instability, violent conflict, and economic stagnation lasting for about a half-century. The parallels suggest that Africa might be exiting from a period of postimperial collapse and entering one of relative political stability and economic growth, as did Latin America almost two centuries ago.African and African American StudiesEconomicsGovernmen