Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 9 of 9

Full-Text Articles in Engineering

A Descriptive Performance Model Of Small, Low Cost, Diskless Beowulf Clusters, Curtis R. Nielson Sep 2003

A Descriptive Performance Model Of Small, Low Cost, Diskless Beowulf Clusters, Curtis R. Nielson

Theses and Dissertations

Commodity supercomputing clusters known as Beowulf clusters, have become a low cost alternative to traditional supercomputers. Beowulf clusters combine inexpensive computers and specialized software to achieve supercomputing power. The processing nodes in a diskless Beowulf cluster do not have a local hard disk unlike the nodes in most commodity clusters. Research has provided performance information for diskless clusters built with expensive, high performance equipment. Beowulf clusters use commodity off-the-shell hardware, and little information is available about their performance. This research includes the construction of several diskless Beowulf clusters. Using the NAS Parallel Benchmarks, the performance of these clusters was measured. …


Efficacy Of Speed Monitoring Displays In Increasing Speed Limit Compliance In Highway Work Zones, Jeanne Marie Bowie Jul 2003

Efficacy Of Speed Monitoring Displays In Increasing Speed Limit Compliance In Highway Work Zones, Jeanne Marie Bowie

Theses and Dissertations

Safety in highway work zones has become a concern among Departments of Transportation (DOTs) throughout the country as the highway network has begun to age and more maintenance and construction work has been necessary. Safety in highway work zones is more compromised than in other areas for two reasons. First, the construction workers are near traveling vehicles as they perform their already dangerous work, increasing the risk of an accident. Second, the highway user is at increased risk because of the increase in roadside obstacles, because other vehicles are more likely to act in unpredictable ways (such as sudden braking …


Sculpting: An Improved Inside-Out Scheme For All Hexahedral Meshing, Kirk S. Walton Apr 2003

Sculpting: An Improved Inside-Out Scheme For All Hexahedral Meshing, Kirk S. Walton

Theses and Dissertations

Generating all hexahedral meshes on arbitrary geometries has been an area of important research in recent history. Hexahedral meshes have advantages over tetrahedral meshes in structural mechanics because they provide more accurate results with fewer degrees of freedom. Many different approaches have been used to create all-hexahedral meshes. Grid-based, inside-out, or superposition meshing all refer to a similar meshing approach that is a very common mesh generation technique. Grid-based algorithms provide the ability to generate all hexahedral meshes by introducing a structured mesh that bounds the complete body modeled, marking hexahedra to define an interior and exterior mesh, manipulating the …


Characterization Of Chlorinated Solvent Degradation In A Constructed Wetland, Nathan D. Clemmer Mar 2003

Characterization Of Chlorinated Solvent Degradation In A Constructed Wetland, Nathan D. Clemmer

Theses and Dissertations

Widespread chlorinated ethene contamination of aquifers coupled with high costs of current treatment technologies demand innovative remediation solutions. Wetlands, maintaining anaerobic and aerobic zones promoting the complete degradation of chlorinated ethenes such as Tetrachloroethylene (PCE), could be the answer. This thesis characterized the chlorinated solvent contamination levels in three strata of an upward flow constructed wetland. Analysis of samples was accomplished by purge-and-trap gas chromatography. Water quality parameters, Dissolved Oxygen (DO), Oxidation Reduction Potential (ORP), pH, Conductivity, and Temperature, were also measured in monitoring wells with a water monitoring sonde. After removing data outliers caused by short-circuiting flow, PCE concentrations …


Palladium-Catalyzed Destruction Of Nitro Aromatic-Contaminated Groundwater, Dennis Landon Phillips Mar 2003

Palladium-Catalyzed Destruction Of Nitro Aromatic-Contaminated Groundwater, Dennis Landon Phillips

Theses and Dissertations

Of the over 17,000 DoD sites that potentially require remediation, sites containing soil and groundwater contaminated by energetic compounds are prevalent (Larson et al., 2001). Production of energetics such as 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5 - trinitro- 1,3,5 -triazine (RDX), and octahydro-1,3,5,7-tetranitro- 1,3,5,7-tetrasocine (HMX) for use in munitions has created a DoD-wide problem due to improper disposal techniques (Price et al., 2001), Nitro aromatic compounds (NACs) similar to those used in explosives can also be found in insecticides, herbicides, pharmaceuticals, dyes, plastics, and many other commonly used products. The natural breakdown of these contaminants creates byproducts such as amines, which are known …


Modeling Catalytic Destruction Of Subsurface Contaminants In Recirculating Wells, Kerry J. Cadena Mar 2003

Modeling Catalytic Destruction Of Subsurface Contaminants In Recirculating Wells, Kerry J. Cadena

Theses and Dissertations

Groundwater and soil contamination is a significant problem throughout the nation, with approximately 300,000 to 400,000 sites affected (National Research Council, 1994). Examples of groundwater contaminants of special interest to DoD and AF installations include fuel hydrocarbons, chlorinated hydrocarbons, and nitroaromatic compounds. Traditional remediation technologies, which include pump-and-treat, permeable reactive barriers, and natural attenuation, have numerous drawbacks associated with them. These drawbacks have prompted researchers to look for innovative contamination clean-up methods. The technology investigated in this thesis, reticulating horizontal flow treatment wells (HFTWs) with in-well palladium (Pd) catalyst reactors, offers the potential for destruction of groundwater contaminants commonly found …


Optimizing An In Situ Bioremediation Technology To Manage Perchlorate-Contaminated Groundwater, Mark R. Knarr Mar 2003

Optimizing An In Situ Bioremediation Technology To Manage Perchlorate-Contaminated Groundwater, Mark R. Knarr

Theses and Dissertations

Combining horizontal flow treatment wells (HFTWs) with in situ biodegradation is an innovative approach with the potential to remediate perchlorate-contaminated groundwater. A technology model was recently developed that combines the groundwater flow induced by HFTWs with in situ biodegration processes that result from using the HFTWs to mix electron donor into perchlorate-contaminated groundwater. A field demonstration of this approach is planned to begin this year. In order to apply the technology in the field, project managers need to understand how contaminated site conditions and technology design parameters impact technology performance. One way to gain this understanding is to use the …


Analysis Of Air Force Civil Engineering Strategic Planning, Francis J. Mondo Jr. Mar 2003

Analysis Of Air Force Civil Engineering Strategic Planning, Francis J. Mondo Jr.

Theses and Dissertations

Several organizations within the Department of Defense, including the Air Force Civil Engineer, are actively engaged in strategic planning in an effort to create a roadmap for future capabilities and performance. The objective of this research was to analyze the strategic planning process of the Air Force Civil Engineer (CE) as well as the effectiveness of the Civil Engineer Strategic Plan (CESP). The methodology used to complete this analysis was conducted in two distinct phases: 1) process modeling and evaluation, and 2) performance measure evaluation. The first phase compared the CE strategic planning process to a theoretical planning model developed …


A Proposed Military Construction Facility Investment Model, Andre R. Dempsey Mar 2003

A Proposed Military Construction Facility Investment Model, Andre R. Dempsey

Theses and Dissertations

The fiscal year (FY) 1999 and FY2000 National Defense Authorization Acts (NDAA) amended Title 10 USC, Section 17, and directed the secretary of defense to report annually on the capability of installations and facilities to provide support to forces in the conduct of their missions. This has come to be known as the Installations' Readiness Report (IRR). The Air Force's IRR links facility sustainment, restoration, and modernization (SRM) requirements, with the impact on the installation's ability to support the mission associated with the particular facility class. The Air Force's centralized military construction (MILCON) program model used to program major facility …