Yes / Simulation of the suspended sediment concentration (SSC) has great significance in predicting the sediment transport rate, vegetation growth and the river ecosystem in the vegetated open channel flows. The present study focuses on investigating the vertical SSC profile in the vegetated open channel flows. To this end, a model of the dispersive flux is proposed in which the dispersive coefficient is expressed as partitioned linear profile above or below the half height of vegetation. The double-averaging method, i.e. time-spatial average, is applied to improve the prediction accuracy of the vertical SSC profile in the vegetated open channel flows. The analytical solution of SSC in both the submerged and the emergent vegetated open channel flows is obtained by solving the vertical double-averaging sediment advection-diffusion equation. The morphological coefficient, a key factor of the dispersive coefficient, is obtained by fitting the existing experimental data. The analytically predicted SSC agrees well with the experimental measurements, indicating that the proposed model can be used to accurately predict the SSC in the vegetated open channel flows. Results show that the dispersive term can be ignored in the region without vegetation, while the dispersive term has significant effect on the vertical SSC profile within the region of vegetation. The present study demonstrates that the dispersive coefficient is closely related to the vegetation density, the vegetation structure and the stem Reynolds number, but has little relation to the flow depth. With a few exceptions, the absolute value of the dispersive coefficient decreases with the increase of the vegetation density and increases with the increase of the stem Reynolds number in the submerged vegetated open channel flows. / Natural Science Foundation of China (Nos. 11872285 and 11672213), The UK Royal Society – International Exchanges Program (IES\R2\181122) and the Open Funding of State Key Laboratory of Water Resources and Hydropower Engineering Science (WRHES), Wuhan University (Project No: 2018HLG01).

In an organism's natural environment, there are always an uncountable number of stimuli, and stimulus features, available to gain control over behavior. When these component stimuli are presented simultaneously, this new stimulus compound can occasion a previously unseen effect on behavior. Stimulus compounding is a method used to better understand how variables in stimulus features may impact the final effect on an organism's responding when presented with a stimulus compound. While stimulus compounding experiments are often conducted using intermodal tone and light stimuli, it is conducted far less often using intramodal stimuli, potentially due to the competing stimulus features of same-modality stimuli. Even less conducted research has been done using two odor component stimuli, despite the large impact odor has on many species' behavior. The purpose of this study was to conduct a stimulus compounding experiment using intramodal ambient odor stimuli in rats, to see what kind of effect a mixed odor compound would have on the subject's behavior. This was done using a wind tunnel designed operant chamber, where both subjects were trained to respond to independently presented odor stimuli. Following training a compound mixture of both component odors was presented to the subjects. The results of this study demonstrated an averaged effect on behavior, producing a response rate under the compound mixture that was intermediate to the response rates under each independent component stimulus. This may be due to several factors, including the efficacy of initial training procedures, the efficacy of the apparatus, and the merging of the component stimuli's features.

This dissertation consists of three essays. The first essay estimates a demand function for compressed natural gas as a fuel substitute to diesel fuel for firms with hybrid fleets. The data is from the Energy Information Administration, for the years 1989 to 2009, for 47 states. Results show that an increase of $0.10 in the price of diesel fuel will increase compressed natural gas demand by 5.59%. The second essay focuses on regional trade agreements (RTAs). A number of studies have found that RTAs significantly increase members' trade flows. While recent studies have begun to explore the reasons for this, none have examined whether the RTA trade effect varies systematically with the number and type of policy areas covered by the agreement. While the empirical trade literature has shed considerable light on the trade-creating ability of RTAs (Grant and Lambert, 2008), much less is known about why these agreements are so successful. In this study, we draw on a new database from the World Trade Organization of trade policy areas covered by RTAs to examine whether the degree of trade liberalization is an important determinant of the RTA trade effect. An augmented, theoretically consistent gravity equation is developed to explore the effects of RTAs on trade, conditional on the policy areas they include. In particular, we investigate two policy areas that are particularly important for agricultural trade, sanitary and phytosanitary measures (SPS) and technical barriers to trade (TBT). The results suggest that harmonization of non-tariff measures inside RTAs matters: Agreements that liberalize these policies increase members' agricultural trade by an additional 62 percent compared to agreements that do not. We conclude that studying the components of RTAs -- in particular, the policy areas covered by these agreements -- is important when analyzing the determinants of RTA trade effects. The third essay uses Bayesian Model Averaging (BMA) to study the effect of membership in the General Agreement on Tariffs and Trade (GATT), the predecessor to the World Trade Organization (WTO), and the WTO on trade flows. Existing GATT/WTO literature is not univocal as to whether membership in the GATT/WTO increases trade flows. In this study, Bayesian model averaging (BMA) is used in the presence of theoretical uncertainty to address whether membership in the GATT/WTO plays a role in the gravity model. Several datasets are examined: a dataset from a previous study; and two datasets compiled for this study, world trade and agricultural trade. Results show, for all three sets of data, that membership in the GATT/WTO does belong in the gravity equation and increases trade flows. / Ph. D.

Experimental data from two cold airflow turbine tests were evaluated. The two tests had different, relatively high gradient flow fields at the turbine exit. The objective of the research was to evaluate data requirements, including the averaging techniques, the number of measurements, and the types of measurements needed, for high gradient flow fields. Guidelines could then be established for future tests that could allow reduction in test time and costs. An enormous amount of data was collected for both tests. These test data were then manipulated in various ways to study the effects of the averaging techniques, the number of measurements, and the types of measurements on the turbine efficiency. The effects were evaluated relative to maintaining a specific accuracy (1%) for the turbine efficiency. Mass and area averaging were applied to each case. A detailed uncertainty analysis of each case was done to evaluate the uncertainty of the efficiency calculations. A new uncertainty analysis technique was developed to include conceptual bias estimates for the spatially averaged values required in the efficiency equations. Conceptual bias estimates were made for each test case, and these estimates can be used as guidelines for similar turbine tests in the future. The evaluations proved that mass averaging and taking measurements around the full 360 degree was crucial for obtaining accurate efficiency calculations in high gradient flow fields. In addition, circumferential averaging of wall-static pressure measurements could be used rather than measuring static pressures across the annulus of the high gradient flow field while still maintaining highly accurate efficiency calculations. These are an important finding in that considerable time and cost savings may be realized due to the decreased test time, probe measurements, and calibration requirements.

Yes / Simulation of the suspended sediment concentration (SSC) has great significance in predicting the sediment transport rate, vegetation growth and the river ecosystem in the vegetated open channel flows. The present study focuses on investigating the vertical SSC profile in the vegetated open channel flows. To this end, a model of the dispersive flux is proposed in which the dispersive coefficient is expressed as partitioned linear profile above or below the half height of vegetation. The double-averaging method, i.e. time-spatial average, is applied to improve the prediction accuracy of the vertical SSC profile in the vegetated open channel flows. The analytical solution of SSC in both the submerged and the emergent vegetated open channel flows is obtained by solving the vertical double-averaging sediment advection-diffusion equation. The morphological coefficient, a key factor of the dispersive coefficient, is obtained by fitting the existing experimental data. The analytically predicted SSC agrees well with the experimental measurements, indicating that the proposed model can be used to accurately predict the SSC in the vegetated open channel flows. Results show that the dispersive term can be ignored in the region without vegetation, while the dispersive term has significant effect on the vertical SSC profile within the region of vegetation. The present study demonstrates that the dispersive coefficient is closely related to the vegetation density, the vegetation structure and the stem Reynolds number, but has little relation to the flow depth. With a few exceptions, the absolute value of the dispersive coefficient decreases with the increase of the vegetation density and increases with the increase of the stem Reynolds number in the submerged vegetated open channel flows. / the Natural Science Foundation of China (Nos. 11872285 and 11672213), The UK Royal Society – International Exchanges Program (IES\R2\181122) and the Open Funding of State Key Laboratory of Water Resources and Hydropower Engineering Science (WRHES), Wuhan University (Project No: 2018HLG01)

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