Digital Commons Network^™

An Experimental Study Of Low Speed Open Cavity Flows, Abraham J. Meganathan

Masters Theses

The experimental work is part of an ongoing study aimed at understanding and controlling of cavity instabilities by passive or active steady or unsteady fluid injection. An experimental setup has been designed to quantitatively visualize the flow-field inside the cavity for varying relative dimensions (L/D ratios of 2.0, 2.67, 3.5 and 4.5, W/D of 3.33) at low subsonic speeds ranging from 55 ft/sec to 214 ft/sec using Particle Image Velocimetry (PIV).

The results showed that PIV could provide instantaneous velocity and other flow field data inside and above the cavity. The quality of data is good and may be used …

A Characteristics Finite Element Algorithm For Computational Open Channel Flow Analysis, Zachariah Chambers

Doctoral Dissertations

For the reliable determination of open channel flows, a minimally dissipative flux jacobian decomposition finite element algorithm is developed for the one- and two-dimensional inviscid open channel flow equation systems. The modifed form of the parent kinetic flux divergence is biased by the characteristic speeds, i.e. eigenvalues of the kinetic flux divergence jacobian, to induce along all wavelike propogation directions a dissipation level proportional to the propogation speeds of the solution to the hyperbolic problem statement.

The analysis rigorously investigates the inviscid open channel equation system via non-linear, wave-like solutions and reveals linear dependency issues for the momentum equations in …

A Delay Model For Exclusive Right-Turn Lanes At Signalized Intersections With Uniform Arrivals And Right Turns On Red, Mohammad A. Qureshi

Doctoral Dissertations

Right turn on red (RTOR) is an established part of today’s driving patterns. However,despite several revisions of the Highway Capacity Manual (HCM), the procedures for estimating delay at signalized intersections do not adequately incorporate the effects of RTOR. The HCM currently removes RTOR from the analysis.

This dissertation has developed models of uniform delay that incorporate RTOR based on queuing theory. Queuing accumulation polygons (QAP) were developed that include RTOR. The research developed a classification system for describing any signal phasing into one of 4 classes based on the sequence of 3 red regimes and one green regime.

It was …

Formulation And Assessment Of A Customizable Procedure For Pavement Distress Index, Zongren Wang

Doctoral Dissertations

A customizable procedure for the formulation of Pavement Distress Index (PDI) based on human rating behavior is presented in this dissertation. This procedure formulates PDI as the maximum PDI value in a user-defined scale minus the Total Deduct Value (TDV), which is the sum of the product of each individual Deduct-Value (DV) and its corresponding weight. These weights, defined as a function of corresponding DV-percentages, i.e. individual DV over TDV, are identified using data simulated according to the studies by Sun and Yao (1991) and PAVER, a Pavement Management System (PMS) developed by the U. S. Army Corps of Engineers. …

An Evaluation Of Relationships Among Streamflow And Selected Water Quality Parameters In A Forested High-Altitude Watershed, Molly Sarah Mccann

Masters Theses

A long-term water quality program has been established at the Noland Divide Watershed (NDW) in the Great Smoky Mountains National Park. The Noland Divide Watershed is a spruce-fir forested catchment which has been shown in previous research to receive some of the largest fluxes of atmospherically-deposited nitrogen and sulfur compounds in the world. Streamwater chemistry data from November 1991 through August 1998 for two streams, the "northeast" (NE) and "southwest" (SW) stream, were examined to note results of this deposition on water quality. Automatic monitoring equipment on both streams measure and record pH, conductivity, and temperature readings every 15 minutes, …

A Methodology And Sampling System For Monitoring Nonpoint Source Pollution From Land Uses, Bryan Fleet Staley

Masters Theses

Limited research has been done in developing a nonpoint source methodology and monitoring system that enables the quantitative evaluation of land use impacts on water quality in a single watershed. The development of a methodology and sampling system that specifically targets the runoff component of streamflow is important in determining which types of land uses contribute most to water quality degradation. In addition, an established monitoring strategy and sampling system will provide for the collection of water quality data when the pollution potential is greatest.

Both a monitoring methodology and a computer controlled sampling system have been developed that utilize …

Evaluation Of Factors Affecting Earth Pressures On Buried Box Culverts, Michael Zhiqiang Yang

Doctoral Dissertations

Factors affecting the earth pressures acting on buried box culverts under deep embankments were evaluated by field instrumentation and numerical analyses. Two instrumented cast-in-place concrete culverts were designed and constructed differently. Long term earth pressures under constant embankment height were observed after the completion of construction. Both observed earth pressures and those predicted by numerical analyses were compared with the current AASHTO earth pressure recommendations, as well as the AASHTO design pressures in effect at the time a failed box culvert was designed in the mid 1970s. Field measurements suggested that the previous AAHSTO design pressure (1977, 12th edition) significantly …

Experimental Characterization Of Flow Patterns And Flow Characteristics In The Bulk Mercury Flow Field Of The Spallation Neutron Source Mercury Target, W. David Pointer

Doctoral Dissertations

The Spallation Neutron Source will provide an intense pulsed source of neutrons for neutron scattering research by focusing a high-energy pulsed proton beam on a liquid mercury target. Interactions between the protons and the nuclei of the mercury will result in the production of neutrons through a spallation reaction. The use of liquid mercury obviates concerns with radiation damage associated with solid targets, facilitates removal of the heat deposited in the target, and allows online processing of the target material to reduce the concentration of the products of the spallation reaction. These advantages allow the use of a much higher …

The Design Of A Chemical Plant Using Hysys Simulation Program, Michael Randolph Vaughan

Chancellor’s Honors Program Projects

No abstract provided.

Internal Forces In A Reinforced Concrete Box Culvert, Scott Mitchell Wood

Masters Theses

In 1996, a reinforced concrete box culvert with approximately 19 meters of embankment fill was instrumented with strain gages and pressure cells to determine the internal forces applied to the culvert. Strain and pressure readings were taken for a period of 3 years during and after the construction of the embankment. From a knowledge of the culvert's dimensions and material properties, the strain readings were converted to forces and bending moments. These forces were then compared to the allowable criteria from the American Association of State Highway and Transportation Officials (AASHTO) Standard Specifications for Highway Bridges. A computer model of …

Layer Properties Of Oriented Strandboard, Caryn Steidl

Masters Theses

It is well known that the density varies through the thickness of oriented strandboard, with the face being much denser than the core. Hence, the modulus of elasticity and the strength should vary through the thickness. To determine the variation in these properties through the thickness of the panel, a commercial oriented strandboard panel was sliced into fifteen layers to obtain specimens for tension and compression testing. Using multiple saw blades and spacers mounted on an arbor in a milling machine, thin specimens were obtained both perpendicular and parallel to panel length. The specimens were tested in tension using straight-sided …