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Articles 1 - 19 of 19
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Boundary Control For Automated Sweeping Of Finite Element Meshes, Robert A. Kerr
Boundary Control For Automated Sweeping Of Finite Element Meshes, Robert A. Kerr
Theses and Dissertations
Finite element analysis depends greatly upon a high-quality mesh to be able to provide reasonably accurate answers to engineering problems. Models that need to be analyzed using finite element analysis are becoming increasingly more complex, and correspondingly harder to mesh with good quality. Skew is one quality metric which can cause problems with finite element analyses. This thesis explains how skew is calculated, discusses two common sources of skew: multiply-linked surfaces with interval constraints, and biased edge meshes. Two methods of lessening skew in surface meshes are then presented: the skew control algorithm, and the curve morphing algorithm. These algorithms …
Interval Matching And Control For Hexahedral Mesh Generation Of Swept Volumes, Jason F. Shepherd
Interval Matching And Control For Hexahedral Mesh Generation Of Swept Volumes, Jason F. Shepherd
Theses and Dissertations
Surface meshing algorithms require certain relationships among the number of intervals on the curves that bound the surface. Assigning the number of intervals to all of the curves in the model such that all relationships are satisfied is called interval assignment. Volume meshing algorithms also require certain relationships among the numbers of intervals on each of the curves on the volume. These relationships are not always captured by surface meshing requirements. This thesis presents a news technique for automatically identifying volume constraints. In this technique, volume constraints are grouped with surface constraints and are solved simultaneously. A sweepable volume has …
Optimal Pulsed Pumping Schedule Using Calculus Of Variation Methodology, Tay W. Johannes
Optimal Pulsed Pumping Schedule Using Calculus Of Variation Methodology, Tay W. Johannes
Theses and Dissertations
Application of a variational optimization technique has demonstrated the potential strength of pulsed pumping operations for use at existing pump-and-treat aquifer remediation sites. The optimized pulsed pumping technique has exhibited notable improvements in operational effectiveness over continuous pumping. The optimized pulsed pumping technique has also exhibited an advantage over uniform time intervals for pumping and resting cycles. The most important finding supports the potential for managing and improving pumping operations in the absence of complete knowledge of plume characteristics. An objective functional was selected to minimize mass of water removed and minimize the non-essential mass of contaminant removed. General forms …
Analysis Of Cost Growth In Us Air Force Base Support Function Contracts, James S. Romasz
Analysis Of Cost Growth In Us Air Force Base Support Function Contracts, James S. Romasz
Theses and Dissertations
The United States Air Force (USAF) has outsourced a significant portion of their activities defined as commercial activities and plans to aggressively outsource more in the future. The USAF outsources its commercial activities in the form of multi-year contracts to the private sector. Cost growth (either negative or positive) has been experienced by most of these contracts. This research effort performed a review of current literature and used statistical analysis to clarify the issue: what are the causes, and extent of cost growth in USAF base-support-function contracts?. From the literature, it can be concluded that changes to the statement of …
Expeditious Method For Estimating Cleanup Costs At Department Of Defense Installations In Korea, John M. Griffin
Expeditious Method For Estimating Cleanup Costs At Department Of Defense Installations In Korea, John M. Griffin
Theses and Dissertations
The purpose of this research was to develop and test a method that can be used to expeditiously estimate costs of hazardous waste site remediation at US DoD installations in Korea allowing decision-makers to formulate remediation strategy. This objective was addressed through answering the following questions: (1) What cost and time constraints do the decision-makers have in developing remediation cost estimates; (2) What degree of accuracy do the decision-makers require in cost estimates; (3) What estimating models are available for determining costs of remediation activities; (4) Have models been used to estimate remediation activities' costs at Korean installations; and (5) …
Biodegradation Of Aircraft Deicing Fluid Components In Soil, Baron W. Burke
Biodegradation Of Aircraft Deicing Fluid Components In Soil, Baron W. Burke
Theses and Dissertations
Aircraft de-icing fluids (ADFs) are used worldwide to ensure safe aircraft operations. This research effort was conducted to analyze the biodegradation effects of two chemical components of ADFs, propylene glycol (PG) and tolyltriazole (TTA), in a high-clay soil. The research used four test methods; automated respirometry, high performance liquid chromatography (HPLC), microbial colony population counts (MCPC), and agar well diffusion tests (AWDT). The research was partitioned into two phases of investigation. Phase-one analyzed individual and combined ADF chemical components on uncontaminated soil. The presence of TTA, from 25 - 1,000 mg/kg, reduced the maximum respiration rate of 1,000 mg/kg PG …
Textual Analysis Of Environmental Compliance Assessment Program Findings, Arthur L. Gepner Jr.
Textual Analysis Of Environmental Compliance Assessment Program Findings, Arthur L. Gepner Jr.
Theses and Dissertations
The United States Air Force (USAF) is committed to assessing environmental compliance; this is achieved in the USAF through the Environmental Compliance Assessment Management Program (ECAMP). These ECAMP audits are designed strictly to assess compliance performance at one point-in-time. They are not intended to assess underlying environmental management systems. This study provides insight into the USAF Environmental Management System (EMS) through a textual analysis of ECAMP data. The analysis discovers eleven categories that emerged from the data: performance, communication, documentation, coordination, training, guidance, notification, resource, human resource, material resource, and financial resource. These categories display a hierarchical relationship. This hierarchical …
Resolving Problems In Engineering Ethics: Precept And Example, Joel C. Adair
Resolving Problems In Engineering Ethics: Precept And Example, Joel C. Adair
Theses and Dissertations
This thesis has served to accomplish several objectives. First, a foundation was laid for the consideration of ethical factors in an engineering context. This was done by first establishing the need for ethical judgement in the engineering disciplines. A summary of several significant classical ethical theories followed, providing several tools with which to evaluate decisions that have ethical implications. Finally, the conclusion was made that the best framework for making ethical decisions is found in the application of the virtues espoused by the gospel of Jesus Christ.
Cost-Benefit Analysis Of Cosolvent Flushing To Treat Groundwater Contamination Source Areas, Stacey L. Anason
Cost-Benefit Analysis Of Cosolvent Flushing To Treat Groundwater Contamination Source Areas, Stacey L. Anason
Theses and Dissertations
Dense non-aqueous phase liquids (DNAPLs) in the zone beneath the water table can be a virtually permanent source of groundwater contamination that cannot be remediated by currently available technologies. Cosolvent flushing is a new technology that has the potential to remediate these sites and could pose a solution to the problem of DNAPL source areas. A computer model was developed to determine the cost and time to remediate an aquifer using cosolvent flushing. Included in the model is a module to calculate the costs of recycling the alcohol that is used as the cosolvent. The model was validated using site …
Substrate Availability In Solid Waste Landfills, Brian D. Benter
Substrate Availability In Solid Waste Landfills, Brian D. Benter
Theses and Dissertations
Numerous models exist to both predict and represent the many biological activities that occur in the modern landfill. These different models use varying methods of characterizing what is happening, what is thought to happen, or what should be happening based on both empirical data and theoretical reasoning. The model presented here is an extension of the system dynamics model originally presented by Colborn in 1997. The revamped model presents a different perspective on what happens as solid organic waste is transformed to simpler substances. This new view involves a bacterial population performing hydrolysis whose growth is limited by the amount …
Development Of Site Characterization Simulator, Neil W. Kassel
Development Of Site Characterization Simulator, Neil W. Kassel
Theses and Dissertations
The purpose of this study was to develop a tool for Remedial Project Managers (RPMs) to learn and practice the site characterization process. One of the key difficulties encountered by RPMs during site characterization is the need to develop a model of the site based on limited data. These limited data are used to determine parameters that describe hydrogeologic and contaminant properties (aquifer hydraulic conductivity, contaminant concentration, etc.) and are obtained using sampling techniques that interrogate a very small volume, usually much smaller than node spacing of the computer model used to simulate site conditions. The value of the parameter …
Environmental Management Strategies In Public Sector Organizations, Charles P. Roberts
Environmental Management Strategies In Public Sector Organizations, Charles P. Roberts
Theses and Dissertations
Environmental management research investigates environmental and ecological practices in organizations. Environmental strategy models or typologies are developed to classify organizations according to their environmental and ecological practices. Past research for environmental management strategy has focused on the profit sector versus the public sector. Drivers such as market and financial forces may not be as evident in the public sector as they are in the profit sector. This research explored environmental management strategies in public sector organizations. An environmental management strategy typology was developed to investigate the structural aspects of organizations. The typology and respective instruments were used in a case …
Concept Design And Optimization Of Msw Management System, James R. Palmer
Concept Design And Optimization Of Msw Management System, James R. Palmer
Theses and Dissertations
The maximum recovery of recyclables from municipal solid waste (MSW) using material recovery facility (MRF) technologies is determined. Two waste streams at Spangdahlem AB, Germany are analyzed; stationary container wastes and commingled recyclables. Three schemes are considered, one for each waste stream, and one for both. Multi-criteria decision making is the methodology. The criteria are recovery and annual benefit minus cost (B-C). Recovery is determined using the recovery factor transfer function of Diaz et al. (1982). Each technology, or unit operation, in a sequence is independent because particle size distribution of each waste component is considered. B-C is based on …
Exploring The Management Of Outsourcing And The Determination Of Civil Engineering Minimum Manning Numbers In Order To Optimize Air Force Benefits, David J. Anason
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
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 …
Expeditious Methods For Site Characterization And Risk Assessment At Department Of Defense Hazardous Waste Sites In The Republic Of Korea, Dean H. Hartman
Expeditious Methods For Site Characterization And Risk Assessment At Department Of Defense Hazardous Waste Sites In The Republic Of Korea, Dean H. Hartman
Theses and Dissertations
The overall goal of this research was to provide Department of Defense (DoD) decision-makers in the Republic of Korea (ROK) with preferred innovative site characterization technologies and risk assessment methods to meet their needs in obtaining hazardous waste site data and then prioritizing those sites for remediation based upon risk. The study examined the following: primary sources and types of existing contamination at DoD installations in the ROK; available site characterization data; criteria to be used in selecting innovative site characterization technologies; costs and capabilities of the innovative site characterization technologies; risk assessment or risk-based corrective action (RBCA) methods available …
Individual Housing Choices Among Air Force Members, Michael J. Johnson
Individual Housing Choices Among Air Force Members, Michael J. Johnson
Theses and Dissertations
Air Force members have three different housing choices: live in MFH, rent in the local community, or buy a house in the local community. A set of six constructs (Housing Attributes, Safety, Pet Importance, Location, Military Housing Perception, and Community) that encompass members' considerations is developed and analyzed. The data was extracted from a survey that was specifically designed to illicit the relative importance of each construct during the housing decision making process. Each construct was measured using a Likert scale score. Statistical analysis was performed to determine the overall Likert mean score for each construct. Using the Likert mean …
Sorption Of The Aircraft Deicing Fluid Component Methyl-Benzotriazole In Soil, David L. Kellner
Sorption Of The Aircraft Deicing Fluid Component Methyl-Benzotriazole In Soil, David L. Kellner
Theses and Dissertations
The air transportation industry requires deicing/anti-icing (ADAF) fluids to maintain flight operations in cold weather conditions. Additives to the ADAF aid in the performance of these agents. Approximately 52M liters of concentrated aircraft deicing fluid are used in North America per year in an attempt to correct this safety problem. Among the additives to ADAF are corrosion inhibitors flame retardants, wetting agents, and thickening agents. Some of these agents are known to be toxic to microorganisms. Identification of the transport processes of these agents in the environment is a necessary first step to understanding how to remediate ADAF. Methyl-Benzotriazole (MeBT) …
Natural Attenuation Of Chlorinated Ethenes By Anaerobic Reductive Dechlorination Coupled With Aerobic Cometabolism, Derek D. Veerkamp
Natural Attenuation Of Chlorinated Ethenes By Anaerobic Reductive Dechlorination Coupled With Aerobic Cometabolism, Derek D. Veerkamp
Theses and Dissertations
Chlorinated solvents and their daughter products are the most common contaminants of groundwater at industrial and military facilities in the United States. Limitations of conventional technologies have intensified efforts to find alternative methods to remediate contaminated sites to regulatory goals set by CERCLA. Natural attenuation of chlorinated solvents is a promising alternative to traditional pump and treat methods but has not been well understood or widely accepted. This modeling study investigated the ability of TCE to completely degrade under various aquifer conditions and rate order constants. It also examined a case study of a former landfill site at Moody AFB. …