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This thesis describes research carried out to study steep streams. Step-pool sequences, a typical feature of such streams, were found to occur on every steep stream studied in the field. The most important control on the spacing of the steps was width. Flume experiments produced steps (at an average Froude number of 0.88), and showed that the presence of steps increased resistance to flow at lower than step-forming flow and decreased resistance at above step-forming flows. In the field, flow resistance was found to be controlled by sediment characteristics and the amount of step protrusion. The hydraulic geometry of the steep streams was also studied, and was found to differ considerably from hydraulic geometry characteristics of lowland streams. The formation of steps and pools was not found to be related to antidune processes; rather they were built up individually as large particles captured other large particles that had been entrained by the near critical flow. It was concluded that it is not the absolute values of slope and discharge that determines whether steps form. Near critical flow and high relative roughness appear to be the only requirements necessary. Previous equations were generally found to perform poorly when used with the experimental data, and an attempt to model the velocity profile using sediment characteristics and considering stresses on the flow also produced poor correlation with the actual field data. Modifications to these were made with some success, especially in the ability to predict friction factor based on relative roughness using D84 . Flume velocity profiles identified characteristic velocity profiles at different locations within the step-pool sequence and the presence 'S-shaped' profiles downstream of the step.

Series: Schriftenreihe des Instituts für Transportwirtschaft und Logistik - Logistik

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An efficient pool is critical for CAT administrations. Two approaches have been developed to design an optimal CAT pool: the linear programming method (LP; Veldkamp & van der Linden, 2000, 2010) and the bin-and-union method (BU; Reckase, 2003, 2010). This study manipulated different content balancing approaches and exposure conditions to investigate their impacts on the pool performances of the LP and BU methods under practical testing situations. The optimal pools were constructed in terms of the specification of an operational fixed-length CAT program and the IRT model employed. This study considered the one-parameter logistic (1PL) model to simulate adaptive test item responses using optimal and operational pools. Several psychometric properties were compared between the pools designed under the LP and BU methods. This research attempted to answer the following question: Under the consideration of content balancing and exposure control, what were the benefits and limitations of the LP and BU methods with respect to the optimal pool design? The results were evaluated in terms of pool characteristics, content constraint management, item exposure control, pool utilization, test reliability, and measurement precision. Similar pool characteristics were found between the LP and BU methods. With respect to the evaluation criteria, the LP and BU pools exhibited consistent performance. However, compared to the LP pools, the BU pools demonstrated slight superiority under the condition with strict content balancing and exposure control. Given two bin widths (.35 and .70), the pools with a bin-width of .35 exhibited better performance than those with a bin-width of .70 with respect to various evaluation criteria. Especially under the condition with the strict content balancing and exposure control, a bin-width of .35 might be a better option to generate an optimal pool than a bin-width of .70 in order to maintain a higher test on-target rate.

A Common Pool Resource (CPR) is a natural or man-made resource system with open or widespread access where the resources are depletable with increased use. CPR examples include forests, pastures, irrigations, rivers, lakes, and fisheries. This research examines a common pool resource in Thailand, i.e. a canal in Nonthaburi Province (NP). The canal, named Klong Om-Klong Bangkok Noi-Klong Bang Kruai, is utilised for agriculture, transportation, commerce, tourism and aesthetics. Currently, urbanisation threatens the canal through changes in land use along the canal. Also, an increasing amount of garbage and water hyacinths in the canal are degrading the quality of the canal environment and waterway transportation. The aims of this thesis were to identify essential factors in the canal system that support the success of collective action in environmental management. This study analyses CPR management in the NP canal system by applying design principles illustrated by long-enduring CPR institutions. These have been identified by Elinor Ostrom (Ostrom, 1990; 1992) and by analysing the situational variables as barriers or resources for collective action. The research was conducted on five communities in Thailand. The primary data collection techniques were qualitative and consisted of two different interview processes and five focus groups. The interviews were completed with local residents and government officials while the focus groups were completed with individuals from five communities. The N6 computer program for handling qualitative data was used to analyse the responses.

The relationship between nutrients and community structure is poorly understood in open-coast habitats. I created a system of artificial tidepools, of identical age and physical dimensions, at two sites that differed in wave exposure, and manipulated nutrient levels and the abundance of herbivores. Using these unique field mesocosms, I explored the role of changes in nutrient dynamics and tested two predictive models of community structure in a rocky intertidal community. I modified a simple food-chain model to include the effect of hydrodynamics on nutrient delivery rates and herbivore foraging efficiency. Field experiments demonstrated that nutrients had strong effects on the abundance and productivity of seaweeds. Algal productivity was negatively influenced by herbivory, contrary to model predictions, because species with the potential to increase growth rates when given additional nutrients were virtually eliminated in the presence of herbivores. The effects of both nutrients and herbivory varied in a manner consistent with predicted effects of hydrodynamic forces. Contrary to simple food-chain models, herbivores did not respond to nutrient additions. I assessed nutrient dynamics during low tide, demonstrating that nutrients were rapidly depleted from tidepools. I also examined variation in nutrient uptake rates relative to the experimental treatments described above, for both whole pools and on a biomass-specific basis. Nutrients were almost always removed from pools at the same rate dispensers added them. Uptake rates were significantly correlated with the abundance of fleshy seaweeds. Synthesizing the results of these and other studies, I proposed that the abundance of tidepool seaweeds can be modeled as a function of pool volume, degree of tidal isolation, water flow at high tide, and herbivory. I tested the predictions of a functional group model and evaluated the validity of equating physical and biological disturbances by examining algal diversity and abundance patterns in tidepools along gradients of potential productivity, herbivory, scour and wave exposure. The abundance of functional groups varied along environmental gradients, but not always in a manner consistent with predictions. I suggested that physical and biological processes must be modeled separately, and that better operational definitions of environmental potentials will aid in development of these models. / Graduation date: 1999

Transportation accidents and the resulting fires are an important field of study. At the University of Waterloo Live Fire Research Facility (UWLFRF), an experiment was conducted in partnership with Sandia National Laboratories in Albuquerque, New Mexico. This experiment was designed to simulate an aircraft accident where fuel is spilled on the runway and is subsequently ignited. A crosswind pushes the 2.0 m diameter pool fire towards the aircraft fuselage and the conditions around the fire are monitored. Literature on the subject is examined first, examining the relationship between the fire, the crosswind, and the 2.7 m diameter blocking object (aircraft fuselage). A full wind characterization is then presented of the UWLFRF both with and without the blocking object in place, using five distinct wind speeds ranging from 3 m/s to 13.5 m/s. Turbulence intensity measurements are made on the centerline of the facility when possible. Details about the two sets of live fire tests are presented, a control experiment without the blocking object in place and then fire tests with the blocking object in place. Additionally, the control experiment has two different setups, one involving a floor surround in order to diminish the effect of the forward facing step on the front of the fuel pan. The fuel regression rate, the wind speed, the ambient conditions and the heat flux near the fuel pan are monitored during each live fire test. The fuel regression rate, defined as the rate at which the height of the liquid fuel level decreases as the fire burns, is then analyzed versus all other monitored variables. During no blocking object tests, trends of increasing wind speed and increasing heat flux on some gauges and decreasing flux on others was observed with increasing fuel regression rate when the floor surround was in place. During no blocking object tests without the floor surround and tests with the blocking object in place, no strong trends were observed when comparing the monitored variables. The ambient conditions were not observed to have an effect on any test. The average fuel regression for tests without the blocking object in place is 4.0 mm/min without the floor surround, and 4.4 mm/min with it in place. With the blocking object in place the average fuel regression rate was measured to be 4.8 mm/min using load cells and 4.1 mm/min using the sight glass.

Previous research has demonstrated that pool-riffle bedforms play a critical role in channel stability and ecosystem health in many natural gravel-bed channels. Although the bedform length is known to scale with channel width, no experimental research has yet isolated the effect of bedform length on pool-riffle hydrodynamics. To improve the understanding of the hydrodynamics of these bedforms so that they can be better incorporated in restoration practices, flume experiments were conducted testing the flow at seven different bedform lengths. Velocity profiles are measured in a 17 m flume with movable PVC bedforms using ultrasonic velocity profilers (UVPs). Smooth two-dimensional (no sinuosity) bedforms are used in order to isolate the key dynamics in convective acceleration and deceleration. The angle of transition between pool and riffle heights was 7°, so that permanent flow separation did not occur. Parameters calculated from the velocity and turbulence profiles include the Coles’ wake parameter (a measure of the deviation from the log law), shear stress estimated from the velocity profile, shear stress estimated from the Reynolds shear stress, and vertical velocity. From the individual velocity time series, the integral length scale and the integral time scales are also calculated. Overall, the length of riffles and pools exert a fundamental control on the distribution of flow and turbulence within a channel. In the pool, energy is dissipated both through turbulence and as the flow is redistributed to uniform flow conditions. In the riffle, kinetic energy increases as the flow velocity increases, and as the length increases, the flow moves towards a new uniform flow condition. The results start to explain the reasons behind the persistent scaling relation between width and bedform length. It can be concluded that uniform flow conditions exist at the end of the pool when the bedform length ratio is greater than approximately 1:5.0 when the riffle length is held constant, and that uniform flow conditions are no longer observed at the end of the pool when the bedform length ratio exceeds 1:7.0 when the pool length is held constant. Future research should concentrate on extending the results to include three-dimensional pool-riffle configurations, repeating bedform configurations, internal scaling parameters, and sediment transport. Ultimately, as the hydrodynamics of pool-riffle sequences are better understood, better bedform designs can be implemented in restoration projects.

This thesis presented an empirical study exploring the performance of TFT-LCD industry through vertical integration in value chain. Statistical analysis methods were adopted to examine the performance of TFT-LCD industry. The following theories of the profit pool and DuPont financial analysis approach, supplemented by competitive strategies, vertical integration, value chain and profit pool theory literature, from the industry overview and key aspects of the value chain Profit distribution and changes in the degree of value chain integration impact on the profitability of panel makers. In this research, we focused on the different segment of the TFT-LCD value chain (color filters, polarizers, backlight module, driver IC and panel manufacturing). We used three financial performance indices of these companies between 2005 and 2009,namely ROE (Return on Equity; ROE), return on total assets (Return on Asset; ROA), operating margin (Return on Sales; ROS) such as most scholars commonly used financial indicators as measurement tools observe all aspects of the value chain profit changes. Finally from the perspective of profit pool and vertical integration strategies to examine whether TFT-LCD panel manufacturers could use an integration strategy as a way to improve their performance on operating profit margin and lower the risk. The results are as follows: the value of different levels of vertical integration, panel makers will do the performance of the operating profit margin have different effects, with the active dwell Taiwan¡¦s TFT-LCD industry up the value chain integration, is indeed closer to or exceed the Korea TFT-LCD maker, but with the TV panel sales with a gradual increase in the proportion of the panel sales , sales channel became a key factor in whether or not profitable. Therefore, the panel makers may be able to consider more closer cooperation with the player of home appliance industry and downstream continuing down the value chain to make the direction of integration efforts.