Civil and Environmental Engineering Commons^™

Reliability-Based Underseepage Analysis In Levees Using Monte Carlo Simulation, Lourdes Polanco

All Graduate Theses and Dissertations

A new method for assessing the potential for unsatisfactory levee performance due to underseepage is presented. Specifically, the method assesses the potential for the initiation of piping (the internal backward erosion of the foundation or embankment caused by seepage). Current assessment methods consist of deterministic seepage analyses and simplified reliability methods. Deterministic methods produce either a maximum hydraulic exit gradient or a Factor of Safety against piping but they do not account for high levels of uncertainty in soil properties and subsurface geometry that are inherent to many levee analyses. The most common simplified reliability approaches that are currently being …

Distributed Hydrological Modeling Using Soil Depth Estimated Based On Landscape Variables From Enhanced Terrain Analysis, Teklu K. Tesfa

All Graduate Theses and Dissertations

The spatial patterns of land surface and subsurface characteristics determine the spatial heterogeneity of hydrological processes. Soil depth is one of these characteristics and an important input parameter required by distributed hydrological models that explicitly represent spatial heterogeneity. Soil is related to topography and land cover due to the role played by topography and vegetation in affecting soil-forming processes. The research described in this dissertation addressed the development of statistical models that predict the soil depth pattern over the landscape; derivation of new topographic variables evaluated using both serial and parallel algorithms; and evaluation of the impacts of detailed soil …

Changes In Hybrid Poplar Endophytic Microbial Diversity In Response To Trichloroethylene Exposure, Jared S. Ervin

All Graduate Theses and Dissertations

Remediation of trichloroethylene (TCE) is a major priority for many contaminated sites all over the industrialized world including Hill Air Force Base, UT (HAFB). Phytoremediation as part of a cleanup strategy is an appealing option, and trees at HAFB have been studied to this end. Trees have also been used to delineate groundwater plumes because the passive uptake of organic contaminants by trees generally results in a direct relationship between tree and groundwater TCE concentrations if the trees are using the contaminated groundwater. However, the concentrations of plant-produced TCE metabolites can vary greatly. It was hypothesized that the endophytic microbial …

Biodegradation And Bioremediation Of Hexachlorocyclohexane Isomers, Chlorinated Ethenes, Chlorinated Benzenes And Benzene, Vijaikrishnah Elango

All Dissertations

ABSTRACT
Groundwater at an industrial site is contaminated with γ -hexachlorocyclohexane (HCH) and α-HCH (i.e., lindane) (0.3-0.5 ppm). Other contaminants in the 1-15 ppm range include 1,2,4-trichlorobenezene (TCB), 1,2-dichlorobenzene (DCB), 1,3-DCB, 1,4-DCB, chlorobenzene (CB), benzene, trichloroethene (TCE) and cis-1,2-dichloroethene (cDCE). The aquifer consists of a shallow layer of soil over fractured dolomite, where most of the contaminant mass resides. The objective of this study was to compare 1) anaerobic reductive dechlorination of the polychlorinated contaminants, followed by aerobic biodegradation of the daughter products (mainly DCBs, CB, and benzene); and 2) aerobic biodegradation of α- and γ-HCH, TCB, DCBs, CB and …

Energy And Nutrient Recovery From Anaerobic Treatment Of Organic Wastes, Christian-Dominik Henrich

All Dissertations

The objective of the research was to develop a complete systems design and predictive model framework of a series of linked processes capable of providing treatment of landfill leachate while simultaneously recovering nutrients and bioenergy from the waste inputs. This proposed process includes an 'Ammonia Recovery Process' (ARP) consisting of: 1) ammonia de-sorption requiring leachate pH adjustment with lime or sodium hydroxide addition followed by, 2) ammonia re-absorption into a 6-molar sulfuric acid spray-tower followed by, 3) biological activated sludge treatment of soluble organic residuals (BOD) followed by, 4) high-rate algal post-treatment and finally, 5) an optional anaerobic digestion process …

College Of Engineering Senior Design Competition Spring 2010, University Of Nevada, Las Vegas

Senior Projects (COE)

Each student in his or her senior year chooses, plans, designs, and prototypes a product in this required element of the curriculum. The senior design project encourages the student to use everything learned in the engineering program to create a practical, real-world solution to an engineering challenge.

A highlight of the year-long senior design project is the senior design competition. This competition, which usually takes place the week before finals each semester, helps focus the senior students on increasing the quality and potential for commercial application for their design projects.

Judges from local industry evaluate the projects on innovation, commercial …

A Concise Model Of 3x7 Wire Rope Used In Cable Guardrail Systems, Cody S. Stolle

Mechanical (and Materials) Engineering -- Dissertations, Theses, and Student Research

Wire rope is a versatile, flexible, high-strength member that is used in many mechanical systems. However, due to the complexity of wire rope, analytical investigations have been relatively limited. Previous attempts to create simplified models of wire rope were not validated with physical testing and used a cumbersome beam-and-shell or beam-and-solid method for simulating the wire rope. An improved LS-DYNA model of 19-mm diameter 3x7 wire rope commonly used in roadside cable guardrail installations has been developed. A Belytschko-Schwer beam element was selected along with material *MAT_166. Since wire rope displays internal damping due to friction of strands and wires, …

Using Buckling-Restrained Braces In Eccentric Configurations, Gary S. Prinz

Theses and Dissertations

Ductile braced frames are often used to resist lateral earthquake loads in steel buildings; however the presence of a brace element can sometimes interfere with architectural features. One common type of ductile braced frame system sometimes used to accommodate architectural features is the eccentrically braced frame (EBF). In order to dissipate seismic forces, EBF beam regions (called links) must sustain large inelastic deformations. EBF links with column connections must transmit large moments and shear forces to facilitate link rotation. Experiments have shown that welded link-to-column connections tend to fracture in the link flange prior to large link rotations. This study …

Site Design Of A Four-Story 11,705 Sq-Ft Class A Office Building, Britney Richmond, Allison Porrett, Kimberly Warners

Honors Theses

This senior capstone design project was a two-semester long venture that began last fall with the formation of the team, the selection of the sponsored project, and the conclusion of a proposal. The purpose of the proposal was for the senior design team to display a thorough understanding of the project's scope of work and to declare the deliverables agreed upon by the team. The team began contact with the sponsor, Hurley &Stewart, prior to beginning the proposal writing in order to gain more details about the project at hand and to ask any questions. The team chose to add …

Determination Of Material Emission Signatures By Ptr-Ms And Their Correlations With Odor Assessments By Human Subjects, Kwanghoon Han

Kwanghoon Han

The objectives of this study were to determine volatile organic compound (VOC) emission signatures of nine typical building materials by using proton transfer reaction-mass spectrometry (PTR-MS) and to explore the correlation between the PTR-MS measurements and the measurements of acceptability by human subjects. VOC emissions from each material were measured in a 50-l small-scale chamber. Chamber air was sampled by PTR-MS to determine emission signatures. Sorbent tube sampling and TD-GC/MS analysis were also performed to identify the major VOCs emitted and to compare the resulting data with the PTR-MS emission signatures. The data on the acceptability of air quality assessed …

A Risk Analysis Of Stevedoring Operations In Seaport Container Terminals, Kuo-Chung Shang, Wen-Jui Tseng

Journal of Marine Science and Technology

This research is a study of container terminals in Kaohsiung Harbor and investigates risk management in the loading and unloading of container terminals. The study shows that the top three factors associated with severity of accident risk are: “Moving the crane without raising the lifting arm of the gantry crane, resulting in damage to the pilot’s compartment,” “Transferring containers direct to the trailers,” and, “As a result of climatic factors (typhoons), the facility takes no action to prevent collisions.” The top three factors associated with frequency of accident risk are, “Ships go by and waves cause a declined-body, raised prow …

Ahp Model For The Container Port Choice In The Multiple-Ports Region, Chien-Chang Chou

Journal of Marine Science and Technology

In this paper, a theoretical analysis of the effect of surface roughness on the lubrication characteristics of inclined stepped composite bearings with micropolar fluid is examined. A generalized form of surface roughness is mathematically modeled by a stochastic random variable with non-zero mean, variance and skewness. The generalized average Reynolds type equation is derived for the rough inclined stepped composite bearings with micropolar fluid. The closed form expressions are obtained for the fluid film pressure, load carrying capacity, frictional force. These expressions can be utilized to obtain the performance characteristics of four different types of bearing system viz; rough plane …

Escalamiento De Dispersión De Contaminantes En La Ciudad De México, Francisco J. Valdes-Parada, J. Ruben Varela-Ham

Francisco J. Valdes-Parada

En días hábiles, la actividad vehicular más intensa en calles y avenidas de la ciudad de México se inicia a las 6:00 hs y se prolonga por aproximadamente 3 ó 4 horas. En ese periodo, la capa de mezclado permanece relativamente quieta y expuesta a recibir una carga importante de contaminantes producto de emisiones vehiculares. En esas condiciones de ausencia de movimientos atmosféricos verticales y horizontales, y de intensa actividad contaminante, adquieren importancia los procesos de dispersión que ocurren en la horizontal y a nivel del suelo.

En este trabajo se lleva a cabo un proceso de promediado de las …

Siding Attachment To Cold-Formed Steel Walls Through Varying Layers Of Foam Insulation, Newport Ventures, Inc., Applied Residential Engineering Services

CCFSS Library (1939 - present)

When insulating an exterior wall, more and more codes are requiring continuous insulation on the exterior of the studs to reduce the effect of thermal bridging. As energy codes continue to become more stringent, the thickness of the continuous installation has increased. Although wood and steel are both impacted, the requirements generally are higher for steel framing.

A significant implementation challenge caused by increasingly higher levels of continuous insulation is the lack of specifications for the type of fastener and siding installation details that should be used when installing thicker levels of insulation. Thus, the engineer, architect, builder, and contractor …

Field Evaluation Of Asphalt Overlays On State Route 30 In Northern Utah, Mark J. Butler

Theses and Dissertations

The purpose of this research was to compare the rutting, cracking, and development of roughness of two asphalt overlay types commonly used in northern Utah and to evaluate how well the Mechanistic-Empirical Pavement Design Guide (MEPDG) can predict the observed results. AC-10 and PG 64-34 asphalt overlay materials were paved in a checkerboard pattern at a test site on State Route 30 near Logan, Utah, and observed for 3 years at 6-month intervals. Primary data included rutting, cracking, and roughness. At the conclusion of the 3-year evaluation period, rut depths were 0.08 in. deeper, on average, in the AC-10 overlay …

East Bay Energy Consortium Meeting Minutes, April 5, 2010, East Bay Energy Consortium

East Bay Energy Consortium Meeting Minutes

No abstract provided.

Polarization Of Galvanic Point Anodes For Corrosion Prevention In Reinforced Concrete, Margareth Dugarte

USF Tampa Graduate Theses and Dissertations

The polarization performance of two types of commercial galvanic point anodes for protection of reinforced steel around patch repairs was investigated. Experiments included measurement of the polarization history of the anode under constant current impressed by galvanostatic circuits and in reinforced concrete slabs. The tests revealed, for both types of anodes, a potential-current function (PF) indicating relatively little anodic polarization from an open circuit potential at low current levels, followed by an abrupt increase in potential as the current approached an apparent terminal value. Aging of the anodes was manifested by a continually decreasing current output in the concrete tests, …

Study On Properties Of Rice Husk Ash And Its Use As Cement Replacement Material, Hilmi Mahmud

Hilmi Mahmud

This paper investigates the properties of rice husk ash (RHA) produced by using a ferro-cement furnace. The effect of grinding on the particle size and the surface area was first investigated, then the XRD analysis was conducted to verify the presence of amorphous silica in the ash. Furthermore, the effect of RHA average particle size and percentage on concrete workability, fresh density, superplasticizer (SP) content and the compressive strength were also investigated. Although grinding RHA would reduce its average particle size (APS), it was not the main factor controlling the surface area and it is thus resulted from RHA's multilayered, …

Integral Formulation For The Solution Of Closure Problems In Upscaling Processes, Francisco J. Valdes-Parada

Francisco J. Valdes-Parada

The derivation of transport models at macroscopic scales can be carried out using upscaling techniques such as the method of volume averaging. This upscaling technique consists on averaging the transport equations that describe phenomena at the microscale. The result is the so-called eective medium models, which are expressed in terms of eective coecients that can be computed from the solution of the corresponding closure problems. In this work, we present an integral formulation based on Green's functions to carry out the formal solution of closure problems. This methodology not only provides a physical interpretation of the closure variables, but it …

A Comparison Of Biocolloid And Colloid Transport In Single Saturated Rock Fractures, Junlei Qu

Sarah E Dickson

No abstract provided.