Digital Commons Network^™

Simulating Migration Of Contaminated Sediments In The Lower Columbia Slough System, Min Chen

Dissertations and Theses

Recent screening-level risk assessment of Slough sediments initiated by the City of Portland identified five contaminated areas in the Slough as posing the greatest potentially significant risks to human health. These five areas were recommended for accelerated remedial action.

But one question remains, does the sediment contamination at these hot spots change over time in response to the changing Slough hydrodynamics? Specifically, will the contamination move or spread even before remedial action is taken? Will they still be there by the time when potential remedial action is taken? Will any new hot spots be created in response to nonuniform transient …

A Design Of A Marine Radar Mast System For Minimum Vibration, Suey-Yueh Hu

Dissertations and Theses @ UNI

This experimental research focused on four areas: (a) the design of a new procedure for imitating the dynamic behavior of an electronic base plate on a radar mast system; (b) determination of a reasonable oscillation modal state; (c) avoidance of the destruction of the ability of the radar on the mast of a ship to receive and analyze incoming signals; and (d) design of a vibration absorber and vibration isolator based on an oscillation frequency. An adapted design for the vibration absorber and vibration isolator contributed to the prevention of excessive amplitude being produced by random forces acting upon a …

Introduction To Simulation/Optimization Modeling For Groundwater Containment Remediation And (B) Ramifications Of Applying S/O Modeling To Groundwater Containment Remediation, With Case Study Examples, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

Normal use of a simulation model to develop a groundwater extraction/injection strategy employs the following process: (1) specify management goals, (2) assume a pumping strategy, (3) simulate system response to the pumping strategy, (4) evaluate acceptability of the system responses, (5) repeat steps (2-4) as required. This is a trial and error approach that is unlikely to actually yield the best pumping strategy for complicated problems

Optimal In-Situ Bioremediation System Design Using Parallel Recombinative Simulated Annealing, Horng-Jer Shieh, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

Presented is a simulation/optimization (S/0) model combining optimization with BIOPLUME II simulation for optimizing in-situ bioremediation system design. The (S/0) model uses parallel recombinative simulated annealing to search for an optimal design and applies the BIOPLUME II model to simulate aquifer hydraulics and bioremediation. Parallel recombinative simulated annealing is a general-purpose optimization approach that has the good convergence of simulated annealing and the efficient parallelization of a genetic algorithm. We propose a two-stage management approach. The first stage design goal is to minimize total system cost (pumping/treatment, well installation and facility capital costs). The second stage design goal is to …

Moment-Rotation Relationship For Unified Auto-Stress Design Of Continuous-Span Bridge Beam And Girders, Donald W. White, J. A. Ramirez, Karl E. Barth

JTRP Technical Reports

This report summarizes the development and trial application of simplified moment-rotation relationships for inelastic design of continuous-span beam and girder bridges. The research described within involves the execution of a reasonably comprehensive set of finite element parametric studies to fill in knowledge gaps in the available experimental data pertaining to the hogging moment-plastic rotation behavior of steel and composite steel-concrete bridge girders. Based on these studies, relationships have been developed for the moment-plastic rotation behavior at the pier sections in these types of bridges. The moment-rotation model is validated against available experimental data, several focused new experimental tests, and current …

Multiobjective Optimum Design Of Static And Seismic-Resistant Structures With Genetic Algorithm, Fuzzy Logic And Game Theory, Dan Li

Doctoral Dissertations

"The goal of this research is to develop a constrained multiobjective optimization method in the form of a robust, practical, problem-independent algorithm, and to investigate the effect of multiobjective optimization on structural design.

This research studies the properties and characteristics of multiobjective optimization and solutions. Design objectives, constraints and design variables as well as their effect on structural design and behaviors are investigated. Dynamic input energy for a multidegree-of-freedom structure is formulated. A multiobjective optimization algorithm based on game theory is developed. Fuzzy set theory is introduced to construct a fuzzy constrained environment. A Pareto genetic algorithm is developed based …

Development Of Synthetic Soils For Sorption Mass Transfer Model Validation, Thomas P. De Venoge

Theses and Dissertations

Existing sorption models often fail to describe grain scale sorption because of an inability to define the diffusion domain. A proposed improved model required testing to determine model validity. The testing method used a synthetic media of known geometry such that the distribution of sorption sites was known. Sorption rate data was obtained using batch experiments with the media. Data was used in comparison against model predicted rates. Fined sorption site distributions were compared to real distributions obtained by controlling sorbent geometries. Comparison determined model performance in fitting known distributions. The focus of this study was to (1) determine what …

Study Of Desorption Of Contaminant From Synthetic Soil, Kung-Fu Hwang

Theses and Dissertations

A better understanding of sorption and desorption processes could improve estimates of time and cost required for remedial activities, exposure times and health risk, and bioavailability. Conventional rate-limited sorption models do not accurately define the diffusion domain at the grain scale. Heyse (1994) proposed the multiple sites in series (MSS) model, which allows more general description of the geometry of the sorption domain than the classical spherical or discrete distributions. A version of this model was tested by deVenoge (1996). The model was able to accurately simulate sorption rate data, but could not estimate unique geometry parameters. This research is …

Investigation Of Sorption Mass Transfer Models Using Synthetic Soils, Karla K. Mika

Theses and Dissertations

Grain-scale sorption mass transfer is an important process that must be considered when predicting clean-up time and choosing remediation techniques for subsurface hazardous waste contamination. Rate-limited sorption is responsible for the rebound effect, where remediated groundwater is recontaminated by desorption. Sorbed contaminants are not available for microbial degradation, and the desorption rate may govern the effectiveness of natural attenuation by biodegradation. Grain-scale sorption nonequilibrium is generally attributed to diffusive transport, either in SOM or in mineral micropores. Typically used sorption mass transfer models either fail to reproduce long-term slow desorption (first-order models), or are based on diffusion in assumed (often …

Development Of Site Characterization Simulator Specifications, Jeffrey L. Heiderscheidt

Theses and Dissertations

The purpose of this study was to develop a tool for evaluating data quality when characterizing a potentially contaminated groundwater aquifer, and to provide a basis for developing a simulator to allow environmental managers and engineers to practice and learn about the site characterization process. Specifically, this study characterized the uncertainty, estimation block size, and cost for the various methods of determining the value of each geological, hydrological, and contaminant parameter necessary to characterize a site. Research entailed identifying site characterization objectives and identifying parameters necessary to obtain those objectives. Methods of estimating each parameter were identified, then research was …

Membrane Analogy For Saint-Venant Torsion: New Results, Stephen M. Heinrich

Civil and Environmental Engineering Faculty Research and Publications

The Saint-Venant torsion problem for a twisted shaft may be formulated in terms of the Prandtl stress function (PSF) or the conjugate warping function (CWF), each of which may be interpreted as the transverse deflection of a thin membrane via the well-known membrane (soap-film) analogies. The deflection of the PSF membrane is associated with a uniform transverse pressure loading, whereas the CWF membrane is nonpressurized—its deformation is due solely to imposed deflections along its edge. The utility of the PSF analogy stems from the simple relationships that exist between the geometry of the deformed membrane (slope, enclosed volume) and the …

Burst Strength Of Type 304l Stainless Steel Tubes Subjected To Internal Pressure And External Forces, J. Pretorius, P. Van Der Merwe, G. J. Van Den Berg

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

The findings of an investigation concerning the burst strength of cold-formed Type 304L stainless steel tubes subjected to internal pressure and static external forces are reported in this study. The use of cold-formed stainless steel longitudinally welded tube in pressurised processes in industry are limited due to the belief that seamless tubes have superior resistance to internal pressure. The primary objective of this study was to experimentally and theoretically describe the failure criteria for thin-walled longitudinally welded Type 304L stainless steel tubes subjected to internal pressure and static external point loads and torsion loads. Due to the diversity of the …

Cold-Formed Steel Design By Spreadsheet Program, Scott A. Burns

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

This paper demonstrates how to use advanced features of a spreadsheet program to design cold-formed steel members efficiently. The example presented in the paper concerns a hat section in flexure which is to be designed for maximum bending strength with a restriction on the total amount of steel that can be used. The nature of the formulas and data entered into the spreadsheet program are presented.

Non-Linear Buckling Analysis Of Thin-Walled Metal Columns, C. Jiang, J. Michael Davies

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

Uniformly compressed cold-formed metal columns are susceptible to instability in a variety of modes. In the stability analysis of such a column, using any of the available numerical methods with the exception of the eigenvalue method, the perfect geometry of the column must be ' seeded' with an imperfection in order to cause it to collapse. If the member buckles in a global mode, it is easy to introduce an appropriate imperfection in form of a suitable displaced shape. However, it is more difficult to define the imperfections for the distortional and local buckling modes due to the unknown nature …

The Crash Simulation And Analysis Of The Friendly Mobile Barrier, Bryan Edward Marz

Mechanical & Aerospace Engineering Theses & Dissertations

Mass transportation is an ever increasing alternative being researched and evaluated in today's society. With the increase of demand for such transportation, an increase in safety is also needed. This research entails the analysis of a new idea, The Friendly Mobile Barrier, in railroad crossing barrier design. The design is meant to prevent any approaching vehicle from crossing a railroad track and be survivable for those impacting the barrier.

Research conducted involves the crash simulation and analysis of the Friendly Mobile Barrier. The Friendly Mobile Barrier was analyzed structurally using finite element analysis. An advanced lumped-mass mathematical model software, Crash …

Behavior Of Cold-Formed Steel Web Elements With Web Openings Subjected To Web Crippling And A Combination Of Bending And Web Crippling For Interior-One-Flange Loading, Sameer U. Deshmukh, Roger A. Laboube, Wei-Wen Yu

CCFSS Library (1939 - present)

INTRODUCTION A. GENERAL Conservation is becoming more prevalent in our society as it is a necessity to protect our environment and ensure our future. Recently, this growing environmental awareness has created concerns regarding the use of wood as an appropriate construction material. In addition, economic and safety concerns are pressuring the competitiveness of the wood industry. Timber prices have risen sharply as the result of a supply and demand crisis. Also, the recent devastation to wood structures by storms have led to the adoption of building codes which require engineered residential construction to minimize safety concerns. To improve the feasibility …

The Motor Fuel Tax Evasion Issue In Kentucky, Dwight V. Denison, Merl M. Hackbart

Kentucky Transportation Center Research Report

Tax evasion is an elusive and burgeoning problem. Methods of tax evasion are continually changing and adapting to new methods of tax enforcement. However, there are strategies that can reduce the potential loss due to fuel tax evasion. This study of fuel tax evasion in Kentucky and the southeastern states provides additional information regarding the causes and nature of the road fund tax evasion problem, and identifies state and federal/state efforts to mitigate the tax evasion challenge. The concepts, issues, and recommendations in this report can aid in reducing evasion of the Kentucky motor fuels tax., thereby, enhancing the efficiency …

Comprehensive Conjunctive-Use Management Of Connected Surface Water Groundwater Systems Using Stochastic Inputs And Uncertainties, Seshadri Suryanarayana

Civil & Environmental Engineering Theses & Dissertations

A comprehensive conjunctive-use management model is developed. The dynamics of flow and solute transport processes in connected surface water groundwater systems are integrated by a dual programming management model. The governing aquifer flow parameters and streamflows are treated as stochastic random processes. Multiple realizations of the random field are generated and are explicitly incorporated in a non-linear optimization model along with other system, environmental, and management constraints. To facilitate management of large aquifer systems, a linked simulation-optimization approach is used. The simulation program generates the response matrices for flow and transport processes. The management model then determines optimal well discharges …

The Constant Fracture Angle Model For Cementitious Materials, Suk Ki Kim

Dissertations

Fracture mechanics of concrete has been investigated for the past two decades using linear elastic and nonlinear fracture mechanics concepts. The models proposed so far remain questionable largely due to specimen dependency of the proposed fracture parameters.

In this study, a new approach for modeling the fracture characteristics of concrete and fiber reinforced concrete is proposed. The model depends on the load CMOD relationship rather than the traditional load-deflection principle. Although energy consumed during fracture is definitely a direct function of the load displacement response, it was observed that traditional displacement measurement included an extraneous and erratic portion due to …

Development Of A Multivariate Qsar Model To Predict Desorption Of Halogenated Aliphatic Hydrocarbons From Activated Sludge Solids, Sudhi Ranjan Mukherjee

Dissertations

Data collected from different wastewater treatment processes have provided statistically significant evidence that many toxic organic contaminants on EPA's list of priority pollutants concentrate several orders of magnitude greater than influent concentrations in industrial and municipal wastewater sludges. Because of the reversibility of sorption processes, it is possible for sorbed organic compounds to desorb at a later time, hence making disposal of these sludges a potential problem. Although a number of models have been developed to predict sorption parameters, they have all been based on empirically derived descriptors whose validity is seriously compromised by the variation in available data for …

Advanced Characterization And Leaching Behavior Of Hexavalent And Trivalent Chromium From Waste Material, Erik Moerman

Theses

In this thesis we employed advanced characterization techniques such as XRF, XRD, XPS, SEM, and EDS to provide detailed information about the chromium waste _ specifically chromium valence states (Cr(VI) and Cr(III)), and their chemical association with other phases in the waste matrix.

The removal of Cr(VI) was accomplished by leaching with aqueous solutions containing inorganic anions such as Cl^-, SO₄^2-, PO₄^3- and others. Cr(VI) can be released from the waste by a combination of desorption and ion exchange processes. The efficiency and kinetics of displacing CrO₄^2- from the waste by …

Implementation Of Alf Results To Designing Flexible Pavements In Louisiana, Ludfi Djakfar

Doctoral Dissertations

The Louisiana Transportation Research Center (LTRC) recently conducted a research effort using the Accelerated Loading Facility (ALF). The objective of the research was to evaluate a limited number of alternative base materials and construction techniques envisioned to provide a significant reduction in the occurrence of shrinkage and reflected block cracking in the cement-stabilized bases. Nine test sections were constructed for this research, using the same wearing course material but having different thicknesses of crushed stone and soil cement bases and subbases. The soil cement base is the most commonly used base material in Louisiana, whereas crushed stone is a preferred …

A One-Dimensional Model For Storm Breaching Of Barrier Islands, Cheol Shik Shin

Civil & Environmental Engineering Theses & Dissertations

A set of numerical models is developed for simulating the four stages of barrier breaching characterized by one horizontal spatial dimension.

The SBEACH model is employed for the first stage of dune/beach erosion. The Lax-Wendroff two-step explicit scheme for Stage II is developed to simulate initiation of ocean flood propagation on initially dry barrier islands and the method of characteristics (MOC), is employed to compute additional boundary data. The development of the Preissmann implicit scheme for water motion and a forward time centered space explicit scheme for sediment motion in Stages III and IV provide a tool to study the …

A Receiving Water Quality Model For Dissolved Metal Runoff From A Floating Drydock, Thomas O. Fenn

Civil & Environmental Engineering Theses & Dissertations

A methodology for modeling the water quality mixing zone of dissolved metal bearing storm water runoff is presented with specific application to floating drydocks in a tidal estuary. The method relies upon a solution of the mass balance equation as contained in the computer program, Water Quality Analysis Simulation Program (WASPS), an Environmental Protection Agency (EPA) model. Separate applications are presented for dissolved metal and solid settling to optimize the WASPS program capabilities.

WASPS provides the capability to evaluate the mass balance equation in a finite difference scheme applied over a large number of small volume segments. The program may …

Pc Windows Finite Element Modeling Of Landfill Gas Flow, Stephen R. Mull, Robert L. Lang, Samuel A. Vigil, Harold M. Cota

Civil and Environmental Engineering

A two dimensional demonstration program, GAS, has been developed for the solution of landfill gas (LFG) flow problems on a personal computer (PC). The program combines a Windows™ graphical user interface, object oriented programming (OOP) techniques, and finite element modeling (FEM) to demonstrate the practicality of performing LFG flow modeling on the PC. GAS is demonstrated on a sample LFG problem consisting of a landfill, one gas extraction well, the landfill liner, cap, and surrounding soil. Analyses of the program results are performed for successively finer grid resolutions. Element flux imbalance, execution time, and required memory are characterized as a …

Testing Of Concrete Under Closed-Loop Control, Ravindra Gettu, Barzin Mobasher, Sergio Carmona, Daniel C. Jansen

Civil and Environmental Engineering

Closed-loop testing systems provide the ability to directly control the deformation of the loaded specimen. This considerably enhances the precision, stability, and scope of the experiments. Closed-loop machines can be used to determine the stable response of test specimen or structure by monitoring and controlling the physical quantities that are sensitive to its behavior. The importance of the various components of the closed-loop controlled system and the test configuration is reviewed in the paper. The most critical aspect of designing the test is the choice of the controlled variable. With appropriate controlled variables and good system performance, several interesting and …

Source Zones, Recurrence Rates, And Time Histories For Earthquakes Affecting Kentucky, Ron Street, Zhernning Wang, Issam E. Harik, David L. Allen, James J. Griffin

Kentucky Transportation Center Research Report

Time histories of hypothetical earthquakes, along with their peak-particle accelerations, and 0 and 5 percent damped response spectra are developed as guidelines for the seismic design of highway structures and bridges within Kentucky. The time histories are derived through the use of random vibration analyses, and take into consideration the probability of earthquakes from nearby seismic zones, the attenuation of ground motions with distance in the Central United States, and the possibility of a random event occurring outside of the generally recognized zones of seismicity in the area. Suggested peak-particle accelerations, time histories, and response spectra are intended for use …

Optimal Pumping Strategies To Maximize Dissolved Tce Extraction At Mather Afb, California, Richard C. Peralta, Alaa H. Aly

Civil and Environmental Engineering Faculty Publications

USU first estimated the future TCE concentrations that would result if no pumping strategy were implemented (Figure 5, Scenario AO). Then USU used the procedure of Appendix B with the model formulation of Appendix C to compute optimal pumping strategies. In computing optimal strategies USU cycled until an arbitrary three percent contaminant mass convergence criterion was satisfied.

Nondestructive Dynamic Load Testing Of Bridges Using Strain Sensors, Suzanne Boland

Theses

This thesis investigates the use of nondestructive bridge load testing utilizing strain sensing equipment. Nondestructive bridge load testing has not been used extensively due to lack of expertise and perceived high cost. It can, however, play a key role when an existing bridge needs to be evaluated. Since most evaluation techniques tend to be conservative, the results from such an evaluation may not represent the real properties of the structural members. The true properties of an existing bridge can be identified using the results from nondestructive static and dynamic load testing. The procedures used to identify a structure with the …

Sensivity Analysis And Design Calculations With Biofiltration Models, Michael Lawrence Cohen

Theses

Biofiltration is a new technology for biological treatment of volatile organic compounds present in airstreams. It is a complex process and thus, engineering models which attempt to describe it are by necessity very involved and contain a large number of parameters.

In this study, two models describing biofiltration of airstreams carrying a single pollutant (VOC) were used in detailed parameter-sensitivity studies. One model concerned biofiltration under steady-state conditions, while the second described the transient behavior of the process. The intent of the sensitivity studies was to determine which model parameters need to be known with accuracy in order to allow …