Thesis (Ph.D.)--University of Nebraska-Lincoln, 2008. / Title from title screen (site viewed Sept. 18, 2008). PDF text: ix, 228 p. : ill. (some col.) , maps (some col.) ; 4 Mb. UMI publication number: AAT 3297902. Includes bibliographical references. Also available in microfilm and microfiche formats.

Thesis (Ph.D.)--University of Delaware, 2009. / Principal faculty advisor: Paul T. Imhoff, Dept. of Civil & Environmental Engineering. Includes bibliographical references.

Thesis (Ph.D.)--University of Delaware, 2005. / Principal faculty adviser: James T. Kirby, Dept. of Civil & Environmental Engineering. Includes bibliographical references.

Laboratory tests were conducted to determine the head losses in wyes and manifolds of conventional type, both with and without an internal tie-rod at the theoretical centre of the wye. These wyes and manifolds, having 45°, 60° and 90° subtending angles of the wyes, were symmetrical about the longitudinal axis of the main pipe. The apparatus and method of testing used in the tests are described. The experiment spans a range of Reynold's numbers from 85,000 to 420,000 in the influent main pipe. The analysis of experimental data is based on the energy equation of Bernoulli for the one-dimensional condition. The results of the tests are given in both tabular and graphical form. It appears that the coefficient of the form loss (the ratio of the form loss of a wye or manifold to the velocity head in the main pipe) is a function of the proportional flow of water through the branches, the size of the tie-rod used and the subtending angle of the wye. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

Thesis (Ph. D.)--Rutgers University, 2009. / "Graduate Program in Civil and Environmental Engineering." Includes bibliographical references (p. 194-203).

Project Completion Report, OWRT Project No. A-040-ARIZ / Agreement No. 14-31-0001-4003 / Project Dates: July, 1972 - June, 1974 / Acknowledgement - The work upon which this report is based was supported by funds provided by the United States Department of the Interior, Office of Water Research and Technology, as authorized under the Water Resources Research Act of 1964. / Hydraulic and physicochemical measurements were made on treated sewage effluent releases at established locations within the channel of an ephemeral stream, the Santa Cruz River of Southern Arizona. Water quality samples were taken in sequence so that incremental flows at different hydrograph stages could be traced as the effluent moved downstream. Hydrographs obtained from two H -L flumes were used to calibrate a modified kinematic wave model. Hydraulic parameters from the kinematic model and physicochemical measurements from water quality samples were combined together into a statistical-empirical kinetic model of nitrogen transformations which may occur in sewage effluent releases. There was fair agreement between the measured data and the nitrogen species values calculated with the model. Measured nitrogen species values indicated that the rate of nitrification in sewage effluent releases is related to flow distance and physical characteristics of the stream.

No description available.

Thesis (M.Eng.)--Memorial University of Newfoundland. / Typescript. Bibliography: leaves 238-248. Also available online.

No description available.

Oxygen transfer between flowing surface waters and the atmosphere can be mathematically described as a first-order reaction and is known as stream reaeration. The first-order rate coefficient or stream reaeration coefficient is a necessary input parameter to stream water-quality models and is partially controlled by the hydraulic conditions of the stream. These coefficients may vary for a given stream reach because of varying hydraulic characteristics brought about by streamflow changes. Hydraulic measurements and reaeration coefficient determinations were made on four pool-and-riffle reaches of Middle Fork Beargrass Creek near Louisville, Kentucky using the hydrocarbon gas tracer technique. Measurements were made on each reach for up to seven streamflow conditions ranging from extremely low to medium. Contrary to published findings applicable to reaches not characterized by a series of pools and riffles, the reaeration coefficient was shown to increase with increasing streamflow for all four reaches studied. Therefore, stream water-quality models developed for these, or similar, stream reaches using reaeration coefficients determined at normal streamflow conditions may over estimate the influence of atmospheric reaeration under a much lower flow condition, such as extreme low flow--the selected critical condition for which water-quality models are commonly developed. Twenty-five published equations used for estimating stream reaeration coefficients were evaluated using the measured hydraulic and reaeration data and were shown to generate highly variable and generally inaccurate predictions. Over half of the equations generated mean prediction errors of more than 50 percent. The best equation overall generated a mean prediction error of 15 percent. The equations were also shown to be highly sensitive to the methods used for determining the input parameter values. Four equations were statistically developed from the data collected in this research. Two of the equations provided more accurate estimates for the four studied reaches than any of the 25 published equations. Mean prediction errors for the two were 1.2 and 9.2 percent. For verification, the developed equations were also evaluated against the 25 published equations using published reaeration and hydraulic data from 39 hydrocarbon gas tracer measurements on other streams. The two developed equations which were most accurate for the four study reaches were also determined to be superior to all of the 25 published equations using the verification data. Mean prediction errors for the two equations using the verification data were 2.3 and 5.5 percent. / Ph. D.