Engineering Commons^™

Predicting Solute Transport In Natural Streams - A Stochastic Approach, Xueqing Zhou

Dissertations and Theses

The existing theories for predicting longitudinal dispersion in straight open channels have long been recognized as inadequate when applied to natural rivers. These theories tend to grossly underestimate dispersion in real streams since an important mixing mechanism due to nonuniform river cross-section variations is not explicitly taken into account. Recognizing the important role of stream irregularities on solute transport and the analytical difficulties of classical deterministic analysis, we develop a stochastic approach for analyzing solute transport in natural streams. Variations in river width and bed elevation are conveniently represented as one-dimensional random fields, characterized by their autocorrelation functions. Advection and …

Composting Of Green Waste Under Severe Dry Hot Weather, Magdy Bdel Ghaffar Elbieh

Archived Theses and Dissertations

No abstract provided.

Two Dimensional Finite Element Modeling Of Swift Delta Soil Nail Wall By "Abaqus", Richard James Barrows

Dissertations and Theses

Soil nail walls are a form of mechanical earth stabilization for cut situations. They consist of the introduction of passive inclusions (nails) into soil cut lifts. These nailed lifts are then tied together with a structural facing (usually shotcrete) . The wall lifts are constructed incrementally from the top of cut down. Soil nail walls are being recognized as having potential for large cost savings over other alternatives. The increasing need to provide high capacity roadways in restricted rights of way under structures such as bridges will require increasing use of techniques such as combined soil nail and piling walls. …

Analytical And Simulation Models Of Weaving Area Operations Under Non-Freeway Conditions, Muhammad Shahid Iqbal

Dissertations

The Highway Capacity Manual covers adequately the operation of weaving areas on freeways. Weaving on non-freeway facilities, however, has not been addressed as yet. This research effort presents a state-of-the-art procedural analytical approach and simulation models for the analysis of the level of service and operation of non-freeway weaving areas. Weaving under non-freeway conditions is classified into two broad categories; basic weave and ramp weave. The analytical models for these two weaving categories are calibrated and validated based on data obtained from several sites selected in the states of New Jersey and New York. New level of service criteria are …

The Use And Evaluation Of Cleaner Wicks To Accelerate In Situ Bioremediation Of Organically Contaminated Groundwater And Soil, Brian Michael Sielski

Theses

The adaptation of Cleaner Wicks to accelerate in situ bioremediation of organically contaminated ground water and soil can be accomplished by making minor modifications to the Cleaner Wick design.

Once these changes in the Cleaner Wick design have been made the two primary ingredients necessary for aerobic microorganisms, nutrients and oxygen, can be delivered via the Cleaner Wick to the subsurface environment both above and below the water table to stimulate microbial growth and activity. Therefore, the microbial population will be able to biodegrade the target contaminants, rendering them harmless products such as carbon dioxide and water.

An adequate understanding …

Integration Of Surfactants And Time Release Nutrients With Pneumatic Fracturing Process, Atiqur Md. Rahman

Theses

The objective of this laboratory study was the development of two novel improvements to the pneumatic fracturing process which would extend its present application. The first involved use of surfactant during pneumatic injection, and the second was subsurface injection of "time-release" dry nutrient pellets for enhancement of in situ biodegradation.

Bench scale tests demonstrated that pneumatic fracturing can be successfully performed with air containing a surfactant solution (foam fracturing). The results showed that foam fracturing followed by increased the rate of surrogate contaminant removal from 8% to 10% compared with regular pneumatic fracturing. These increases were attributed to enlarged fracture …

A Gis Based Multi-Modal Multiple Optimal Path Transit Advanced Traveler Information System, Nicholas A. Koncz

Theses

A method for the design and use of a Transit Advanced Traveler Information System (TATIS) using an off-the-shelf Geographic Information System (GIS) is developed in this thesis. The research design included: 1) representing multi-modal transit networks in a digital form with schedule databases; 2) development of a multiple "optimal" path algorithm that takes into account walking transfers using published time schedules; 3) incorporating user preferences and penalties in the algorithm; 4) development of a user-interface with suitable output capabilities; 5) using the prototype for sample inquiries giving performance measures.

This prototype was developed using the Arc/Info GIS developed by ESRI, …

The Influence Of Hydrodynamics And Particle Size On The Rejection Properties Of Ultrafiltration Membranes, Usama M. Shahin

Theses

A mathematical model based on the flow hydrodynamics is developed to calculate the treatment efficiency of ultrafiltration process. This model relates the treatment efficiency with the consideration of both fixed parameters and variable parameters. The fixed parameters are function of the intrinsic rejection coefficient, diffusion coefficient, and viscosity whereas the variable parameters can be related to the fluid velocity, volume flux, and cartridge dimensions. The model has been examined by solutions with solutes that have different molecular weights. The experimental data fits the proposed mathematical model very closely suggesting its suitability to evaluate the rejection efficiency in ultrafiltration. As such …

Behavior Of Concrete And Slender Reinforced Concrete Columns Under Cyclic Axial Compression With Bidirectional Eccentricities, Byong Youl Bahn

Dissertations

A rational analysis of reinforced concrete (R/C) structures requires satisfactory modeling of the behavior of concrete under general loading patterns. The behavioral characteristics of concrete dominantly depends upon its load history. For the study of concrete behavior, parametric study and experimental investigation into the behavior of concrete under load history of random cycles are performed. Through parametric study, the applicability of the previous concrete models is examined and a physically motivated modeling for the cyclic stress-strain relationships is proposed. The present modeling of concrete under general cyclic loading is initiated to provide substantial applicability, flexibility of mathematical expressions and furthermore …

Theoretical Evaluation Of The Break Off Test For Concrete, Arjuna Priyara Ranasinghe

Dissertations

Strength of concrete is normally measured using the standard cylinder or cube. The measured strength is used for design. The accuracy of concrete strength is frequently challenged, particularly in large concrete structures where size effect of the test specimens is attributed for the differences. Many nondestructive tests were developed to evaluate concrete strengths. In recent years, it was obvious that these tests are unreliable. As the infrastructure decays, more nondestructive tests are required to evaluate the existing structures.

The Break Off Test is a recently developed nondestructive test. Although substantial amount of experimental investigations have been carried out on this …

Development Of A Knowledge-Based System For Wastewater Pipeline Rehabilitation, David Allen Reaves

Engineering Management & Systems Engineering Theses & Dissertations

The purpose of this thesis is to study and develop a knowledge-based system to make decisions for the rehabilitation of wastewater pipelines. Development includes justification for the use of an expert system, data acquisition from knowledge experts, program model development, model testing, implementation and future considerations including expansion. The model is developed and implemented using an expert system shell called XIPlus ®.

This knowledge-based system is designed specifically for the Navy Public Works Center Utilities Department at Norfolk Naval Base in Norfolk, Virginia for making decisions for the rehabilitation of the 50-year-old wastewater collection system. Recent sewer collapses and a …

Decision Support Model To Compare Hazardous Waste Site Remediation Process Alternatives, Christopher E. Findall

Theses and Dissertations

This research focuses on the development of a decision support model to identify the preferred methods of site characterization and treatment technology identification using the principles of decision analysis theory. The model provides an effective decision making tool to evaluate and compare the feasibility of using alternative methods of completing the RIFS process. Given a specific site remediation project, the users of this model can enter site- specific cost, duration and likelihood values to determine the expected value for various alternative processes. This thesis postulates that the alternative having the highest expected value is considered the preferred alternative. In calculating …

Design And Analysis Of Constrained Layer Damping Treatments For Bending And Torsion, Kimberly J. Balkema

Theses and Dissertations

In this dissertation, different aspects of constrained layer damping treatments on beams of various geometries are studied. First, the optimal length of a constrained layer damping treatment mounted on a surface in linear strain is identified as a function of the relative stiffnesses of the damping layers and the non-uniformity of the surface stain. The analysis extends previous work that considered the case of uniform surface strain. Sixth order sandwich beam theory is then modified for use with a rectangular beam covered with a segmented constrained layer damping treatment. Non-dimensional variables are used to simplify the form of the problem. …

Application Of A Risk Model To Quantify Relative Risk Of Remedial Actions, Timothy L. Fuller

Theses and Dissertations

To properly manage the Installation Restoration Program (IRP) in the future, Air Force remedial project managers (RPMs) need a metric to assist in the selection of remedial alternatives for the safe and effective clean up of waste contamination sites. If the baseline site risk assessment indicates that it is necessary to remediate a waste contamination site, it is important to the RPM that the selection process for remediation alternatives considers the potential human health and ecological risks associated with the proposed remediation process. In some instances, the risks may be significant when compared to the baseline conditions. The Air Force …

Modeling Trihalomethane Formation Potential From Wastewater Chlorination, Carol A. Mccormick

Theses and Dissertations

The deletion of federally mandated fecal coliform limits has led many states to review and modify their wastewater disinfection requirements. One issue in analyzing wastewater disinfection is the discharge of potentially carcinogenic halogenated organics formed during the chlorination process. This research investigates the formation of one class of the halogenated organics, the trihalomethanes. The applicability of using drinking water trihalomethane formation models for use with wastewater effluent is examined. Three models are compared for predictive capability by using measured trihalomethane values from previous research data. The results show that a previously developed model is applicable for use based on assumptions …

Volatile Organic Compound Emissions From Usaf Wastewater Treatment Plants In Ozone Nonattainment Areas, Brian A. Ouellette

Theses and Dissertations

In accordance with the 1990 Clean Air Act Amendments CAAA, this research conducts an evaluation of the potential emission of volatile organic compounds VOCs from selected Air Force wastewater treatment plants. Using a conservative mass balance analysis and process specific simulation models, volatile organic emission estimates are calculated for four individual facilities--Edwards AFB, Luke AFB, McGuire AFB, and McClellan AFB--which represent a cross section of the current inventory of USAF wastewater plants in ozone nonattainment areas. From these calculations, maximum facility emissions are determined which represent the upper limit for the potential VOC emissions from these wastewater plants. Based on …

Optimal Pulsed Pumping For Aquifer Remediation When Contaminant Transport Is Affected By Rate-Limited Sorption: A Calculus Of Variation Approach, Richard T. Hartman

Theses and Dissertations

The remediation of groundwater contamination continues to persist as a social and economic problem due to increased governmental regulations and public health concerns. Additionally, the geochemistry of the aquifer and the contaminant transport within the aquifer complicates the remediation process to restore contaminated aquifers to conditions compatible with health-based standards. Currently, the preferred method for aquifer cleanup pump-and-treat has several limitations including, the persistence of sorbed chemicals on soil matrix and the long term operation and maintenance expense. The impetus of this research was to demonstrate that a calculus of variations approach could be applied to a pulsed pumping aquifer …

Simulation Of Hydrologic Influences On Wetland Ecosystem Succession, Robert A. Pompilio

Theses and Dissertations

This research focuses on the development of a simulation model to determine the effects of hydrological influences on a wetland ecosystem. The model allows perturbations to the inputs of various wetland data which in turn, influences the successional development of the ecosystem. This research consisted of converting a grassland ecosystem model to one which simulates wetland conditions. The critical factor in determining the success of wetland creation is the hydrology of the system. There are four of the areas of the original model which are affected by the hydrology. The model measures the health or success of the ecosystem through …

Solvent Substitution Methodology Using Multiattribute Utility Theory And The Analytical Hierarchical Process, Jaimie S. Tiley

Theses and Dissertations

This study developed a multicriteria decision making methodology for the ranking of solvent cleaning process alternatives. This includes development of univariate value functions and criteria and the incorporation or required alternative attributes. It also compares the Analytical Hierarchical Process and Multiattribute Utility Theory in reference to a cleaning substitution process. An actual Air Force cleaning process evaluation problem is considered to verify the research. The test problem ranks several cleaning alternatives for the replacement of a hazardous solvent used in the general cleaning of aircraft engine components.

Status Of Storm Water Pollution In The United States, Lynne A. Urquhart

Theses and Dissertations

The purpose of this study was to determine the status of storm water pollution in the United States Air Force. This is important since most AF bases are now required to have applied for a NPDES storm water permit. The objectives of the study were to: evaluate the sampling rates used at AF bases; determine the pollutants tested for by the AF bases; compare the pollutant concentrations of the AF bases to an EPA water quality standard; and determine if there were any trends in sampling or pollutant concentrations due to seasonal changes or across AF Commands or EPA Regions. …

Optimal Utilization Of Field Generated Analytical Data For Site Characterization And Remedial Decision Making, Ronald J. Lester

Theses and Dissertations

This study developed data quality standards for assessing environmental analytical data quality and its use in remedial decision making, specifically in risk assessment calculations. The primary purpose was to increase the use of field generated data in environmental site investigations versus the continued reliance on costly and time consuming EPA Contract Lab Program data. Increased reliance on field lab data could significantly reduce remedial investigation costs. The standards developed are based on regulatory criteria for data useability, achievable quality in a CLP lab setting, and basic statistical methods. The standards were applied to sets of Volatile Organic Compound data in …

An Analysis Of Alternative Methods Of Measuring Hazardous Waste Reduction Progress At The Air Force Materiel Command's Air Logistic Centers, Edward C. Finke

Theses and Dissertations

his study investigated the relationship between aircraft related maintenance activity and the amount of hazardous waste (HW) disposed of by Air Force Materiel Command's (AFMC) Air Logistic Centers (ALC). These ALCS, along with the Aircraft Guidance and Meteorology Center, generate approximately 76 percent of the HW generated by the Air Force. The activity indexing and least squares curve fitting methods were used to predict the amount of HW that would have been disposed of based on the relative level of aircraft related maintenance activity had no pollution prevention efforts been implemented. These predictions were then compared to what historically occurred …

Development Of An Analytical Hierarchy Process (Ahp) Model For Siting Of Municipal Solid Waste Facilities, Dimasalang F. Junio

Theses and Dissertations

Deciding on locations for municipal solid waste facilities is a difficult problem where qualitative criteria compete with quantitative economic and engineering criteria, in an environment that is highly political and emotional. State guidelines often describe different methodologies but fall short in offering a solution or a methodology in arriving at a solution. This study develops a decision modeling procedure, based on the Analytical Hierarchy Process (AHP), that can be used by public sector decision makers to locate and site municipal solid waste facilities. The applicability of the procedure is demonstrated at the City of Springfield, Clark County, Ohio. Research efforts …

Economics Of Chlorofluorocarbon (Cfc) Machine Replacement, Geoffrey D. Rudderow

Theses and Dissertations

Continued use of chlorofluorocarbon CFC refrigerants may have a severe financial as well as operational impact on the users of air-conditioning and other refrigeration equipment as price increases continue and production is phased out. With production of CFCs coming to a halt on 31 December 1995, the two major refrigerants that have been used in commercial and industrial cooling applications will no longer be available. The phase out of production is a result of national and international agreement that these, as well as other CFCs, are a primary cause of the depletion of the stratospheric ozone layer. To help the …

Standardization Of Protocol For The Sampling, Testing And Abatement Of Asbestos Containing Joint Compound, Gary J. Schneider

Theses and Dissertations

This study investigated the differing regulatory guidelines from the Occupational Safety and Health Administration and the Environmental Protection Agency concerning the abatement of Asbestos Containing Joint Compound (ACJC). The specific interest was whether or not adequate protection was being afforded demolition workers when exposed to working with ACJC materials that contain less than 1.0 percent asbestos. A spreadsheet was written to estimate the exposure scenario which might be experienced within a given room size on a demolition or renovation jobsite. Spreadsheets were calculated for ACJC with an asbestos content of 0.1 to 0.9 percent in 0.1 increments for rooms ranging …

A Preliminary System Dynamics Model Of A Constructed Wetland For The Mitigation Of Metals In Usaf Storm Water, Mark P. Smekrud

Theses and Dissertations

This thesis determines the potential removal and corresponding accumulation of trace metals from Air Force storm water in a constructed wetland through the use of a System Dynamics model. The goal is to determine whether constructed wetlands used as storm water best management practices provide efficient metal removal while creating only benign accumulations of such pollutants. Its purpose is to allow Base Civil Engineers and Environmental Managers a better tool to assess the long-term effects of a constructed wetland used as a storm water mitigation technique. The research is limited to the assessment of typical metal concentrations found in Air …

Developing An Emission Factor For Hazardous Air Pollutants For An F-16 Using Jp-8 Fuel, Donald J. Van Schaack

Theses and Dissertations

The 1990 Clean Air Act amendments drastically changed the legislation of hazardous air pollutants HAPs or air toxics. Title 3 of the act which specifically addresses HAPs now lists 189 substances which may require regulation as air toxics. Consequently, the reporting of HAP emissions from all Air Force operations will be required in the future. However, the Department of Defense DoD does not have methods available to report this information. This thesis develops emission factors for selected HAPs from an F-16 CD aircraft F110 engine operating on JP-8 fuel. The methodology included determining which HAPs should be selected, using past …

A Quantitative Method For Screening Pollution Prevention Program Options At United States Air Force Installations, Wayne M. Williams

Theses and Dissertations

US Air Force installations worldwide are required to implement pollution prevention (PP) programs designed to reduce the release of pollutants to the environment, and the Air Force uses opportunity assessments (OAs) to identify and evaluate waste producing processes that could benefit from a PP project. The OA process guidance provides extensive details on how to identify potential projects and on how to economically evaluate a project selected for implementation. However, it provides only cursory information about how to decide which projects should be selected for this evaluation. This thesis bridges that gap by providing a quantitative model to be used …

Evaluation Of Alternative Methods For Wastewater Disinfection, David C. Piech

Theses and Dissertations

This study investigated the alternative methods of wastewater disinfection. Areas of interest included methods of operation, ease of maintenance, and effectiveness for various types of wastewater. A literature search revealed three major disinfection options, which include chlorination dechlorination, ultraviolet light, and ozone. A questionnaire was sent to the active duty Air Force installations that operate wastewater treatment plants, requesting permit limitations and monthly averages for a variety of wastewater parameters. The majority of Air Force wastewater treatment plants use chlorine for disinfection. Using the data obtained from the questionnaire responses and established wastewater parameters from other research, the basic design …

Use Of Infrared Spectrometry To Determine The Effect Of Trichloroethylene Resident Time On Desorption Rates From Flint Clay, Peter T. Lapuma

Theses and Dissertations

This laboratory based thesis investigated the desorption rate of trichloroethylene (TCE) from flint clay while varying the resident time of TCE exposed to the clay. It is thought that in long contaminated soil, a majority of contaminant mass will become entrained within the interior of the soil particles to slowly desorb out of the soil over long periods of time. Recent studies suggest that the longer a contaminant is resident in soil, the longer the contaminant will take to desorb from the soil. To understand more about soil desorption, this experiment was developed using infrared spectroscopy to detect TCE vapor …