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Full-Text Articles in Engineering

Long Term Risks Associated With Brownfield Containments, Shailesh Shirish Chirputkar May 1999

Long Term Risks Associated With Brownfield Containments, Shailesh Shirish Chirputkar

Dissertations

The sites at which the development is hindered by real or perceived contamination are called as Brownfield sites. It is a common trend in industry to develop these types of sites with surface and peripheral containments. It might prove unwise to develop the sites in this manner from a long term perspective without considering the associated risk. Because of this, a model has been proposed for long term risk assessments of brownfield containments.

Objectives of this study were to develop a contaminant transport model for flow of contaminants towards the surface and peripheral containments inside the site, a model for …


Physical And Geotechnical Characterization Of Water Treatment Plant Residuals, Swamy C. Basim May 1999

Physical And Geotechnical Characterization Of Water Treatment Plant Residuals, Swamy C. Basim

Dissertations

The study of Water Treatment Plant (WTP) residuals is of recent origin and very little information is available in literature regarding these residuals. These waste materials have high solids contents, even in the mechanically dewatered condition, making it difficult to handle. These, along with stringent environmental regulations have forced the water utilities to look for new disposal options for these residuals. For this purpose as well as for evaluating suitable options for the beneficial reuse of residuals, it is essential to characterize WTP residuals.

As the dewatered residuals are plastic, the researcher may be prompted to treat these materials as …


Development Of Computer Model And Expert System For Pneumatic Fracturing Of Geologic Formations, Brian Michael Sielski May 1999

Development Of Computer Model And Expert System For Pneumatic Fracturing Of Geologic Formations, Brian Michael Sielski

Dissertations

The objective of this study was the development of a new computer program called PF-Model to analyze pneumatic fracturing of geologic formations. Pneumatic fracturing is an in situ remediation process that involves injecting high pressure gas into soil or rock matrices to enhance permeability, as well as to introduce liquid and solid amendments. PF-Model has two principal components: (1) Site Screening, which heuristically evaluates sites with regard to process applicability; and (2) System Design, which uses the numerical solution of a coupled algorithm to generate preliminary design parameters.

Designed as an expert system, the Site Screening component is a high …


Design And Engineering Of A Tensile Fabric Structure, Jairo Rios May 1999

Design And Engineering Of A Tensile Fabric Structure, Jairo Rios

Theses

Fabric structures are designed in an iterative process between architect and engineer, analysis input and output, and detail and patterning. There are three main steps in designing a fabric structure: shape finding, loading, and patterning/ detailing.

Shapefinding consists of finding the shape of the fabric where the fabric forces are in equilibrium. This type of structure is geometrically nonlinear which require iterative analysis to converge on a unique solution.

The loading of the structure is similar to that of any conventional structures. The departure is in the major effects that suction and ponding have on fabric surfaces.

Usually the details …


In Situ Enhancement Of Well Recovery By Pneumatic Media Injection, Michael Thomas Galbraith May 1999

In Situ Enhancement Of Well Recovery By Pneumatic Media Injection, Michael Thomas Galbraith

Theses

The objective of this thesis was to develop a new process for enhancing recovery wells at hazardous waste sites. The process, known as an extended radius well (ERW), involves injection of ceramic beads directly into groundwater plumes to create drainage paths for liquid contaminants. This is a variant of Pneumatic Fracturing, which is a patented in situ remediation process developed to increase permeability of soil and rock formations by injection of high pressure gas.

The research study comprised laboratory investigations, engineering scale tests, and a field pilot demonstration. The laboratory investigations examined the properties of several candidate media to determine …


The Effects Of Offshore Mining Of Beach Quality Sediments On Nearshore Wave Climate, Frank R. Lonza May 1999

The Effects Of Offshore Mining Of Beach Quality Sediments On Nearshore Wave Climate, Frank R. Lonza

Civil & Environmental Engineering Theses & Dissertations

Coastal communities rely on the beaches to attract tourism, but these sources of revenue require maintenance, such as beach nourishment. In an effort to maintain these beaches without causing any detrimental results, research is conducted to determine what effects, if any, exist when mining for sand in offshore areas.

The U.S. Government is permitting the search for beach quality sands offshore but is also ensuring that such mining will not have adverse results to the nearshore wave climate. This study was conducted using a coarse grid bathymetric map to calibrate a numerical model developed by the Danish Hydraulic Institute (DHI). …


Finite Element Simulation Of Creep Buckling Of Cipp Liners Under External Pressure, Qiang Zhao Apr 1999

Finite Element Simulation Of Creep Buckling Of Cipp Liners Under External Pressure, Qiang Zhao

Doctoral Dissertations

The problem of long-term structural behavior of CIPP liners under external hydrostatic pressure has been characterized as a structural instability problem which is induced by time-dependent material deformation or creep. It is also a contact problem since the liner deflection is externally constrained by the host pipe. The intrinsically nonlinear problem is investigated by means of finite element simulation, with emphases on (a) the essential structural behaviors and mechanisms of buckling, and (b) the influences of inelastic material properties (i.e. yield strengths and creep rates) and geometrical parameters on liner's buckling resistance.

A liner first deforms as a free pipe …


An Empirical Investigation On The Impacts Of Ground-Level Ozone Concentrations On National Ambient Air Quality Standards: The Case Of Lake Charles, Louisiana, Benedict Nweke Nwokolo Apr 1999

An Empirical Investigation On The Impacts Of Ground-Level Ozone Concentrations On National Ambient Air Quality Standards: The Case Of Lake Charles, Louisiana, Benedict Nweke Nwokolo

Doctoral Dissertations

This study presents information upon which the state of Louisiana can base its ozone State Implementation Plans (SIPs) designed to achieve planned emissions reduction that are required by the Clean Air Act (CAAA) of 1990. The research investigation included an assessment survey on a number of Transportation Control Measures (TCMs) and their degree of acceptability by the residents of Lake Charles area of Louisiana, the research target area. The TCMS were first ranked on the basis of people's perception of each TCM and four TCMs were later analyzed for cost-effectiveness using computer mathematical models. The Traffic Flow Improvements TCM was …


Exploring The Management Of Outsourcing And The Determination Of Civil Engineering Minimum Manning Numbers In Order To Optimize Air Force Benefits, David J. Anason Mar 1999

Exploring The Management Of Outsourcing And The Determination Of Civil Engineering Minimum Manning Numbers In Order To Optimize Air Force Benefits, David J. Anason

Theses and Dissertations

This thesis investigates the relationship between peacetime and wartime tasks for Air Force Civil Engineering career fields in regard to outsourcing. Relevant literature in civilian sector outsourcing techniques is then studied to determine how they decide on what to outsource and what to keep insourced. Peacetime tasks performed by individual career fields are correlated with the wartime tasks to determine if there is any valuable wartime training gained from the completion of peacetime work orders. Several interviews completed with Air Force Civil Engineer readiness experts to evaluate an importance factor for each career field wartime mission. This importance factor and …


The Determinants Of Locational Choice For Air Force Military Renters: Implications For Policy, Eldrick L. Hill Mar 1999

The Determinants Of Locational Choice For Air Force Military Renters: Implications For Policy, Eldrick L. Hill

Theses and Dissertations

Housing allowances and military family housing make up approximately $7 billion dollars of the budget for the Department of Defense (DoD). The military uses a Housing Market Analysis (HMA) to determine rental housing availability around its installations. This thesis describes and analyzes the locational choices of military renters. This thesis examines 16 bases in the continental U.S. using military and census data. It is concluded that the locational preferences of military renters vary inversely with distance from their duty location and this needs to be accounted for when assessing the availability of military rental housing. The implications of military renter …


Fluorescence Spectroscopy For The Characterization Of Humic And Fulvic Acids And Their Disinfection By-Products Formation Potential, Ishvinder H. Kochar Jan 1999

Fluorescence Spectroscopy For The Characterization Of Humic And Fulvic Acids And Their Disinfection By-Products Formation Potential, Ishvinder H. Kochar

Theses

Natural Organic Matter (NOM) plays a major role in the formation of undesirable organic by-products following disinfection/oxidation of drinking water. It is suspected that most precursors to disinfection by-products (DBPs) are humic although non-humic substances have not been studied and are suspected of also contributing to DBPs. NOM reacts with many of the disinfectants used to treat drinking water, such as chlorine, chioramine, and ozone, to form a variety of DBPs. Many of these DBPs have adverse health effects in humans (i.e. carcinogenic or mutagenic effects). The primary DBPs of concern include the trihalomethanes (THMs), haloacetic acids (HAAs), and haloacetonitrile …


Elasto-Plastic Responses Of Buried Pipeline Systems Under Wave Propagation, Yuean-Chen Lau Jan 1999

Elasto-Plastic Responses Of Buried Pipeline Systems Under Wave Propagation, Yuean-Chen Lau

Civil & Environmental Engineering Theses & Dissertations

The purpose of this research is to study the elastic and inelastic behavior of buried pipeline system under arbitrary seismic wave propagation. Both continuous and segmented pipes with joints and junctions are included. The surrounding soil is simulated by a series of elasto-plastic springs uniformly distributed longitudinally and laterally along the pipes. To the joints, elasto-plastic longitudinal springs and bilinear rotational springs are adopted. It is assumed that the pipes remain linearly elastic. The effects of soil liquefaction and fault movement are not considered.

Since the dynamic effect has been found to be negligible, a quasi-static analysis is adopted in …


Displacement-Based Analysis And Design Of Rigid Retaining Walls During Earthquakes, Yingwei Wu Jan 1999

Displacement-Based Analysis And Design Of Rigid Retaining Walls During Earthquakes, Yingwei Wu

Doctoral Dissertations

"This research focused on the analysis and design of rigid retaining walls subjected to earthquakes and considered nonlinear foundation soil properties. The simultaneous sliding and rocking movements of retaining walls were considered. Seven field conditions, including moist, submerged, perched and saturated backfill with a sloping drain, were specified by design codes. A computer program capable of computing displacement using real time history records or equivalent sinusoidal motions was developed. Finally, a dynamic design procedure was proposed for practicing engineers.

The study revealed that maximum shear modulus in foundation soil, maximum ground acceleration, and soil nonlinearity had significant effect on the …


Unbound Pavement Base Courses: Parallel Study Of Stiffness And Drainage Characteristics, Moussa Issa Jan 1999

Unbound Pavement Base Courses: Parallel Study Of Stiffness And Drainage Characteristics, Moussa Issa

Doctoral Dissertations

The purpose of this project was to study the effects of fines (minus #4 sieve) on permeability and stiffness characteristics of unbound base materials and to propose an optimumgradation that will satisfy these two parameters. One type of highway base material--crushed limestone--was used in the study. A total of 75 laboratory tests were conducted and distributed--25 respectively on permeability, resilient modulus and unconfined compression. The permeability test data were collected using a low-head permeameter. The resilient modulus and unconfined compression test data were collected by the mean of the MTS (Machine Testing System) with a load cell capacity of 22-kips. …


A Two-Component Aggregation Model, Thomas A. Chisholm Jr Jan 1999

A Two-Component Aggregation Model, Thomas A. Chisholm Jr

Dissertations, Theses, and Masters Projects

An aggregation model which allows specification of primary particle size, density, and fractal dimension for two different particle types was written. Three stickiness values are used, the stickiness of each particle type to itself and the stickiness between particle types. Aggregation mechanisms considered include differential settling and turbulent shear. The model is used in three forms. In its simplest form, it operates on a closed system with aggregates breaking up when their size approaches the Kolmogorov scale. If the system begins with two types of primary particles, larger aggregates have uniform composition. A second version of the model includes removal …