A pilot scale demonstration of a biological permeable barrier was conducted in a pentachlorophenol-contaminated aquifer at a wood preserving facility. A permeable reactor was constructed to fit within a
large diameter well. Arranged in series, a cylindrical reactor 24" x 36" (0.61 x 0.91m) (diameter x height)
was partitioned to...
The addition of exogenously supplied hydrogen stimulates PCP reductive
dechlorination and increases bacterial growth. While research focuses mainly on
pure cultures, few exist capable of aryl reductive dechlorination, and few markers
exist to identify reductively dechlorinating bacteria within mixed cultures.
Furthermore, most active bioremediation projects stimulate mixed cultures of native...
The mixed metal compound, Chromated Copper Arsenate, or CCA, has been widely used as a wood preservative. The metal ions in CCA, CrO²⁻₄, Cu²⁺, and AsO³⁻₄, have been found in contaminated surface and subsurface soils and groundwater nearby some wood preservative facilities and nearby wood structures. Iron oxides are a...
The present research investigates nonlinear barge motions through analyses of coupled multi-degree-of-freedom (MDOF) deterministic and stochastic models. Roll-Heave-Sway and other lower-ordered models are developed to predict the nonlinear motions and analyze the stability of a class of ship-to-shore cargo barges. The governing equations of motion contain coupled rigid body Roll-Heave-Sway...
Two interesting challenges have been created in the traditional transportation planning process through recent adoption of more interactive roles by Federal, State and local transportation agencies and of those representing the communities being impacted by proposed transportation projects. First, the decision-making groups that formerly included solely transportation and related professionals...
Performance-based design has gained interest in recent years among structural designers and researchers. Performance-based design includes selection of appropriate building sites, structural systems and configurations, as well as analytical procedures used in the design process, to confirm that the structure has adequate strength, stiffness and energy dissipation capacity to respond...
The fractal dimension of measured ocean wave profiles is found to be in the range of 1.5-1.8. This non-integer dimension indicates the fractal nature of the waves. Standard formulations to analyze waves are based on a differential approach. Since fractals are non-differentiable, this formulation fails for waves with fractal characteristics....
A considerable amount of research has focused on load-sharing and system effects in repetitive-member wood floor systems subject to transverse loading. However, relatively few studies have been conducted to investigate load-sharing and system effects in repetitive-member wall systems which may be subject to combined transverse and gravity (vertical) loading, and...
Large numbers of 1950's vintage conventionally reinforced concrete (CRC) bridges remain in-service in the national bridge inventory. Many of these bridges are lightly reinforced for shear. Evaluation of these bridges to prevent unnecessary and costly repairs requires refined analytical techniques. This dissertation presents finite element (FE) modeling and comparisons of...
The Asphalt Pavement Analyzer (APA) device was used to characterize the impact of various mix factors on the development of permanent deformation in dense-graded mixes given a standard compactive effort. Factors included two aggregate sizes, three VMA levels, two fines contents, three binder contents and four binder types. All specimens...
A theoretical argument is presented to suggest that engineering curriculum be
designed to develop social capital. Additionally, the value of social capital in the
retention of students in the College of Engineering, and the development, role, and value
of social capital in an electrical engineering laboratory is evaluated. Data collected...
This thesis focused on using microcosms to better understand the aerobic cometabolic processes of TCE and cis-DCE transformation that occurred during a Cometabolic Air Sparging (CAS) demonstration at McClellan Air Force Base. The microcosms were created with groundwater and aquifer materials from the demonstration site. Concentrations of compounds in the...
The cyclic resistance of predominantly fine-grained soils has received considerable attention following ground and foundation failures at sites underlain by silt-rich soils during recent earthquakes. In several cases substantial ground deformation and reduced bearing capacity of silt soils has been attributed to excess pore pressure generation during cyclic loading. These...
A numerical model for the simulation of fully-coupled fluid-structure
interaction is developed in this study. In modeling the fluid, the Reynolds
Averaged Navier-Stokes equations are solved for an incompressible viscous
fluid field and a k-ε model is employed for turbulence computations.
Hydrodynamic forces obtained by the integration of the fluid...
Three-dimensional finite element models are developed to simulate the behavior of four fill-scale reinforced concrete beams. The beams are constructed with different fiber-reinforced polymer (FRP) strengthening schemes, and are modeled using ANSYS, a commercially available finite element analysis program. The experimental beams replicate the transverse beams of the Horsetail Creek...
The Horsetail Creek Bridge (HCB), constructed in 1914, is located along the Historic Columbia River Highway in Oregon. The original cross beams from the HCB were substantially deficient in shear strength, particularly for the projected increase in traffic loads. One control beam and three beams with varying configurations of a...
The Horsetail Creek (HC) bridge is an example of an Oregon bridge that was classified as structurally deficient and was not designed to withstand earthquake (EQ) excitations. A fiber-reinforced polymer (FRP) rehabilitation was performed on the HC bridge to increase flexural and shear capacities for traffic loads. However, a seismic...
Structural design codes have evolved continuously since modern codes were established. The allowable stress design format has been widely used since the late 191h century. During the past two decades, probability-based limit states design concepts have evolved and are increasingly being used for various material and structural types. Limit state...