This thesis presents the details of designing and commissioning the multi-use static/dynamic large-scale soil testing table. The table was developed with the intention of creating a large scale testing apparatus versatile enough to carry out several different types of testing on a large scale. This report describes the background research done to develop the testing table concept and the thinking that went into each component. The apparatus itself consists of a shake table with a laminar soil container (inside dimensions L:100cm W:50cm H:65cm) and a top which can be lowered to apply overburden pressures on specimens. It is set up to run both static and cyclic tests on large soil samples. The final design allows for performing shaking tests with a non-fixed top, static and dynamic simple shear tests, and direst shear tests with minimal changes to the table configuration. The table has separate control and data acquisition systems which are necessary to run and record tests. All components of the table will be explained thoroughly within the thesis. Preliminary testing was done with the table to determine how well it is functioning and what needs to be done to further improve it. Static simple shear and cyclic simple shear tests were both run, and while the table showed some flaws, the results seem promising. It is determined that with proper instrumentation and after addressing some small issues, the testing table can be a useful and versatile tool in the future. This thesis will outline the strengths and flaws of the table as currently constructed and determine what the future applications for this testing apparatus will be. / text

This dissertation focuses on a variety of vadose zone processes that impact water table fluctuations. The development of vadose zone process conceptualization has been limited due to both the lack of recognition of the importance of the vadose zone and the absence of suitable field data. Recent studies have, however, shown that vadose zone soil moisture dynamics, especially in shallow water table environments, can have a significant effect on processes such as infiltration, recharge to the water table, and evapotranspiration. This dissertation, hence, attempts to elucidate approaches for modeling vadose zone soil moisture dynamics. The ultimate objective is to predict different vertical and horizontal hydrological fluxes. The first part of the dissertation demonstrates a new methodology using soil moisture and water table data collected along a flow transect. The methodology was found to be successful in the estimation of hydrological fluxes such as evapotranspiration, infiltration, runoff, etc. The observed dataset was also used to verify an exponential model developed to quantify the ground water component of total evapotranspiration. This analysis was followed by a study which analyzed the impact of soil moisture variability in the vadose zone on water table fluctuations. It was found that antecedent soil moisture conditions in the vadose zone greatly affected the specific yield values, causing a broad range of water table fluctuations for similar boundary fluxes. Hence, use of a constant specific yield value can produce inaccurate results. Having gained insight into the process of evapotranspiration and specific yield, a threshold based model to determine evapotranspiration and subsequent water table fluctuation was conceptualized and validated. A discussion of plant root water uptake and its impact on vadose zone soil moisture dynamics is presented in the latter half of this dissertation. A methodology utilizing soil moisture and water table data to determine the root water uptake from different sections of roots is also described. It was found that, unlike traditional empirical root water uptake models, the uptake was not only proportional to the root fraction, but was also dependent on the ambient soil moisture conditions. A modeling framework based on root hydraulic characteristics is provided as well. Lastly, a preliminary analysis of observed data indicated that, under certain field conditions, air entrapment and air pressurization can significantly affect the observed water table values. A modeling technique must be developed to correct such observations.

A new methodology is proposed for estimation of evapotranspiration (ET) flux at small spatial and temporal scales. The method involves simultaneous measurement of soil moisture (SM) profiles and water table heads along transects flow paths. The method has been applied in a shallow water table field site in West-Central Florida for data collected from January 2002 through June 2004. Capacitance shift type moisture sensors were used for this research, placed at variable depth intervals starting at approximately 4 in. (10 cm) below land surface and extending well below the seasonal low water table depth of 59 in. (1.5 m). Vegetation included grassland and wetland forested flatwoods. The approach includes the ability to resolve multiple ET components including shallow and deep vadose zone, surface interception capture and depression storage ET. Other components of the water budget including infiltration, total and saturation rainfall excess runoff, net runoff, changes in storage and lateral groundwater flows are also derived from the approach. One shortcoming of the method is the reliance on open pan or other potential ET estimation techniques when the water table is at or near land surface. Results are compared with values derived for the two vegetative covers from micrometeorological and Bowen ratio methods. Advantages of the SM method include resolving component ET.

The thesis project is a study for the integration of farming, urban use, and ecology at the edge of the city. The aims of the test-of-principle are to connect the urban consumer with the rural food producer, processing and productive landscape, and to examine mechanisms for local self-sufficiency and the preservation of farmland from suburban encroachment. The proposed model for this study is a sheep farm within the outskirts of Truro, Nova Scotia. At the landscape scale, the thesis takes the position that urban areas and farmland mutually benefit from co-localization. At the site and building scales, the thesis adopts the ‘farm-to-table’ model, seeking to vertically-integrate the full cycle of food-related programming. The public experience within this food hub is choreographed through visibility, porosity and overlapping circuits with farmer, sheep and product. By balancing the public, process and pragmatism, the thesis demonstrates a role for architecture within the agrarian domain.

Genetic factors have been shown to be involved in etiology of a poor response to the antidepressant treatment with sufficient dosage and duration. Our goal was to identify the role of polymorphisms in the poor response to the treatment. To this end, 5 functional polymorphisms in 109 patients diagnosed with unipolar, major depressive disorder are analyzed. Due to the small sample size, exact conditional tests are utilized to analyze the contingency table. The data analysis involves: (1) Exact test for conditional independence in a high dimensional contingency table; (2) Marginal independence test; (3) Exact test for three-way interactions. The efficiency of program always limits the application of exact test. The appropriate methods for enumerating exact tables are the key to improve the efficiency of programs. The algorithm of enumerating the exact tables is also introduced.

Detailed soil and water data are essential to ensure the optimum long-term management of fields. The objective of this study was to estimate water table depths, spatially variable and layered soil properties using electromagnetic induction methods. Soil samples were collected and analyzed within two wild blueberry, a soybean-barley and a pasture fields. Observation wells were installed. The DualEM-2 was calibrated to predict the soil properties and groundwater depths. The apparent ground conductivity (ECa) and water table depths were measured simultaneously from each well, before and after every significant rainfall for three consecutive days. Comprehensive surveys were conducted in selected fields to measure ECa with DualEM-2. Survey data were imported in C++ program to estimate layered soil properties using mathematical models. Regression models were developed to predict soil properties and groundwater depths. The predicted soil properties and groundwater table maps were generated. This information can help to develop variable rate technologies.

The current study compared participants’ ability to perform tasks using two nutrition labels: a control Nutrition Facts table of the current Canadian format (n=64), and an experimental label (n=64), identical to the control label with the exception of a footnote explaining how to interpret percent daily values. A 25% subset of participants answered questions using a think aloud technique, and data was analyzed using content analysis. The main outcome measured was ability to interpret percentages correctly, with ability to compare, define and manipulate information as secondary outcomes. No significant differences were seen in ability to perform tasks between the experimental and control conditions for any outcomes. As determined by chi square tests, higher performance was associated with higher education, being male, and report of previous Nutrition Facts table use. Verbal protocol analysis identified that interpretation of percentages was based on the meal, food type, and comparison to other foods.

I investigated the effects of multi-decadal water table drawdown on carbon (C) exchange, as well as functional relationships between C fluxes and environmental controls, in a boreal rich fen. Drainage increased ecosystem respiration of CO2 and decreased CH4 fluxes, but did not affect understory primary productivity. Drainage altered plant responses to light availability, as well as the responses of ecosystem respiration and CH4 flux to water table position. In a laboratory experiment, I found that drainage reduced potential CO2 and CH4 fluxes suggestive of decreased peat substrate quality. Together, these results indicate that long-term drying increases C losses and that both environmental conditions and substrate quality influenced C fluxes post-drainage. My findings suggest that C losses from increased ecosystem respiration may not be mitigated by increases in plant productivity or decreases in substrate quality, and that long-term drainage reduced C storage capacity in this boreal fen. / The Natural Sciences and Engineering Research Council of Canada

Vertical inclusions of expanded polystyrene (EPS) placed behind rigid retaining walls were investigated as geofoam seismic buffers to reduce earthquake-induced loads. A numerical model was developed using the program FLAC and the model validated against 1-g shaking table test results of EPS geofoam seismic buffer models. Two constitutive models for the component materials were examined: elastic-perfectly plastic with Mohr-Coulomb (M-C) failure criterion and non-linear hysteresis damping model with equivalent linear method (ELM) approach. It was judged that the M-C model was sufficiently accurate for practical purposes. The mechanical property of interest to attenuate dynamic loads using a seismic buffer was the buffer stiffness defined as K = E/t (E = buffer elastic modulus, t = buffer thickness). For the range of parameters investigated in this study, K ≤ 50 MN/m3 was observed to be the practical range for the optimal design of these systems. Parametric numerical analyses were performed to generate design charts that can be used for the preliminary design of these systems. A new high capacity shaking table facility was constructed at RMC that can be used to study the seismic performance of earth structures. Reduced-scale models of geosynthetic reinforced soil (GRS) walls were built on this shaking table and then subjected to simulated earthquake loading conditions. In some shaking table tests, combined use of EPS geofoam and horizontal geosynthetic reinforcement layers was investigated. Numerical models were developed using program FLAC together with ELM and M-C constitutive models. Physical and numerical results were compared against predicted values using analysis methods found in the journal literature and in current North American design guidelines. The comparison shows that current Mononobe-Okabe (M-O) based analysis methods could not consistently satisfactorily predict measured reinforcement connection load distributions at all elevations under both static and dynamic loading conditions. The results from GRS model wall tests with combined EPS geofoam and geosynthetic reinforcement layers show that the inclusion of a EPS geofoam layer behind the GRS wall face can reduce earth loads acting on the wall facing to values well below those recorded for conventional GRS wall model configurations. / Thesis (Ph.D, Civil Engineering) -- Queen's University, 2011-04-28 16:56:57.084

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