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Retrospective Theses and Dissertations

Civil and Environmental Engineering

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Full-Text Articles in Engineering

Advancements In Pervious Concrete Technology, John Tristan Kevern Jan 2008

Advancements In Pervious Concrete Technology, John Tristan Kevern

Retrospective Theses and Dissertations

Pervious concrete has been used for many years in the southern United States but only recently have stormwater mandates implemented by the United States (U.S.) Environmental Protection Agency (EPA) created interest for more wide-spread installations, especially in freeze-thaw climates. Validation of the freeze-thaw durability of pervious concrete under the most extreme conditions created an opportunity to explore many additional aspects of pervious concrete and to improve durability through additional mixture characterization and new construction practices. While the material components are similar to conventional concrete, the idiosyncratic behavior of pervious concrete requires revaluating material effects and relationships. Many different factors ...


Investigation Of Steel Stringer Bridge Superstructures, Jeremy Craig Koskie Jan 2008

Investigation Of Steel Stringer Bridge Superstructures, Jeremy Craig Koskie

Retrospective Theses and Dissertations

There are hundreds of structurally deficient or functionally obsolete bridges in the state of Iowa. With the majority of these bridges located on rural county roads where there is limited funding available to replace the bridges, diagnostic load testing can be utilized to determine the actual load carrying capacity of the bridge. One particular family or fleet of bridges that has been determined to be desirable for load testing consists of single-span bridges with non-composite, cast-in-place concrete decks, steel stringers, and timber substructures.;Six bridges with poor performing superstructure and substructure from the aforementioned family of bridges were selected to ...


Predicting Loads On Ground Engaging Tillage Tools Using Computational Fluid Dynamics, Mark Eugene Barker Jan 2008

Predicting Loads On Ground Engaging Tillage Tools Using Computational Fluid Dynamics, Mark Eugene Barker

Retrospective Theses and Dissertations

A new method of evaluating tillage tools using computational fluid dynamics is proposed. Steady-state CFD only and transient two-way fluid-structure interaction simulations were run to predict draft and vertical forces on a spring-reset field cultivator standard. Using CFD the soil was treated as a visco-plastic fluid using the Bingham-plastic material model. Lab tests were run using a rigid flat steel bar and a production field cultivator standard with 178 and 254 mm sweeps for comparison. The results indicate that the method can be used to reasonably predict the draft force to within three standard deviations of the average measured draft ...


Construction Dispute Mitigation Through Multi-Agent Based Simulation And Risk Management Modeling, Islam Hassan El-Adaway Jan 2008

Construction Dispute Mitigation Through Multi-Agent Based Simulation And Risk Management Modeling, Islam Hassan El-Adaway

Retrospective Theses and Dissertations

The construction industry is regarded not only as a backbone of the nation’s economy but also as an integral indicator of its efficiency and effectiveness. However, as a result of the risks and complexities that are naturally inherent with construction projects as well as the diverging interests of the parties involved, claims and disputes could be considered an unavoidable consequence of the construction processes. In fact, over the years, the frequency and severity of claims and disputes have significantly increased to the extent that the estimated total annual cost of construction conflicts and disputes in the U.S. is ...


Proposed Highway Asset Management Framework With An Emphasis On Economic Impact Analysis, Asish Seeboo Jan 2008

Proposed Highway Asset Management Framework With An Emphasis On Economic Impact Analysis, Asish Seeboo

Retrospective Theses and Dissertations

In highway asset management, the decision making process as regards the allocation of funding to deficient assets is a very complex one, especially when the competing assets have similar traits. Currently, HERS-ST is one of the tools that many departments of transportation across the nation have adopted for this task. The system is capable of capturing and measuring user, non-user as well as agency benefits generated from investment in highway maintenance projects and as such has aided to some extent in the decision making process. In this study the main goal was to devise a system’s framework that would ...


Improving Pavement Marking Performance Through Contrasting New Methods To Quantify Marking Presence And Increasing Installation Efficiencies Through An Evaluation Of Prototype Bead Guns, Craig Michael Mizera Jan 2008

Improving Pavement Marking Performance Through Contrasting New Methods To Quantify Marking Presence And Increasing Installation Efficiencies Through An Evaluation Of Prototype Bead Guns, Craig Michael Mizera

Retrospective Theses and Dissertations

Agencies continue to search for ways to measure and improve pavement marking performance. With regard to measuring performance this research first conducted a comparative study on the pavement marking evaluation process through a comparison of subjective and objective pavement marking durability rating techniques. The subjective and objective performance evaluation processes reported slight differences. In an effort to address pavement marking quality and efficiencies during installation another study was conducted to develop a methodology for evaluating different bead guns used in the pavement marking application process. An experiment evaluated the performance of the bead guns at various speeds. The SpeedBeader(TM ...


Analysis Of Jointed Plain Concrete Pavement Systems With Nondestructive Test Results Using Artificial Neural Networks, Mustafa Birkan Bayrak Jan 2008

Analysis Of Jointed Plain Concrete Pavement Systems With Nondestructive Test Results Using Artificial Neural Networks, Mustafa Birkan Bayrak

Retrospective Theses and Dissertations

The primary goal of this research was to show that artificial neural network (ANN) models could be developed to perform rapid and accurate predictions of jointed plain concrete pavement system (JPCP) parameters which will enable pavement engineers to incorporate the state-of-the-art finite element (FE) solutions into routine practical design. The ISLAB2000 finite element program has been used as an advanced structural model for solving the responses of the concrete pavement systems and generating a large knowledge database.;Totally, fifty-six ANN-based backcalculation and forward calculation models were developed as part of this research for the analysis of JPCP systems under traffic ...


Permeation Of Hydrocarbons Through Polyvinyl Chloride (Pvc) And Polyethylene (Pe) Pipes And Pipe Gaskets, Feng Mao Jan 2008

Permeation Of Hydrocarbons Through Polyvinyl Chloride (Pvc) And Polyethylene (Pe) Pipes And Pipe Gaskets, Feng Mao

Retrospective Theses and Dissertations

Plastic pipes have been used increasingly as a means for the conveyance of drinking water in water distribution systems. Although there are research and case studies documenting the permeation of organic compounds through plastic pipes, there is still a lack of understanding on the performance of PE and PVC pipe materials in hydrocarbon-contaminated soils commonly encountered under field conditions.;A microscopic visualization technique was developed to investigate the permeation of organic solvents through PVC pipes by observing the formation and propagation of organic fronts in pipe materials with a light microscope. The threshold concentrations of toluene where a moving front ...


Rheological Studies On The Flow Behavior Of Two-Phase Solid-Liquid Materials, Gang Lu Jan 2008

Rheological Studies On The Flow Behavior Of Two-Phase Solid-Liquid Materials, Gang Lu

Retrospective Theses and Dissertations

In this dissertation a mathematical approach to model the rheological behavior of fresh cement based materials were completed. A direct shear model of coarse granular material, a yield stress model of cement paste, a shear failure behavior of fresh mortars, and a particle-fluid model for flowing mortar were developed. The model predictions of rheological behavior of cement based materials are in good consistent with the experimental results.


Characterization Of Geomaterials With X-Ray Computed Tomography (X-Ray Ct), Clinton Halverson Jan 2008

Characterization Of Geomaterials With X-Ray Computed Tomography (X-Ray Ct), Clinton Halverson

Retrospective Theses and Dissertations

The application of 3-dimensional volumetric imaging using non destructive evaluation procedures opens doors in researching geomaterials, allowing study of internal characteristics. X-ray computed tomography (CT) is one such procedure which is especially well suited to geomaterials due to the high density contrasts often found between solid materials and their surrounding environments and/or pore spaces. Although X-ray CT has been applied to geomaterial research in the past, there is a lack of tested X-ray CT methodologies which can be readily applied to many important research tasks. Methods developed and applied herein concern the analyses of soil particle movement during application ...


Swine Wastewater Treatment By The Static Granular Bed Reactor, Seung Joo Lim Jan 2008

Swine Wastewater Treatment By The Static Granular Bed Reactor, Seung Joo Lim

Retrospective Theses and Dissertations

Swine wastewater was successfully treated by the SGBR. Two types of swine wastewater samples were used, and the performance of the SGBR was excellent. COD removal efficiency of sample 1 was 84.7∼94.5%, while that of sample 2 was 58.4∼76.6%. The SGBR acted not only as a bioreactor but also as a filter system. The performance of suspended solids removal was excellent irrespective of the OLR. Additionally, the COD removal efficiency in the effluent after backwashing was not a function of the recovery time but that of the OLR.;The SGBR model was developed with ...


Aerodynamic Mitigation Of Extreme Wind Loading On Low-Rise Buildings, Kevin Sehn Jan 2008

Aerodynamic Mitigation Of Extreme Wind Loading On Low-Rise Buildings, Kevin Sehn

Retrospective Theses and Dissertations

Hurricanes and other extreme wind events cause immense devastation to our economy every year. Modern buildings should be designed to withstand extreme wind so that it reduces the financial strain on the economy. An experimental study was performed to compare aerodynamic performance of new roof designs. Traditional roof shapes were also included in this study to determine if the new designs had any merit in aerodynamic roof load mitigation. An atmospheric boundary layer wind tunnel was used with the characteristic wind of a suburban boundary terrain. The force results obtained from measurement of the roof loads showed that the largest ...


Design And Field Testing Of Tapered H-Shaped Ultra High Performance Concrete Piles, Thomas L. Vande Voort Jan 2008

Design And Field Testing Of Tapered H-Shaped Ultra High Performance Concrete Piles, Thomas L. Vande Voort

Retrospective Theses and Dissertations

The strategic plan for bridge engineering issued by AASHTO in 2005 identified material deterioration as one of the primary challenges to achieving extended life. In substructural applications, construction materials such as steel and concrete are subjected to deterioration. Ultra High Performance Concrete (UHPC) has a compressive strength of 26,000 psi (180 MPa) and excellent durability, and this study explores the possibility of using precast, prestressed UHPC piles. An H-shaped UHPC section, which is 10-in. (250-mm) deep, was designed for constructability and economical reasons. Instrumented UHPC elements were cast to conduct large-scale field tests. In the field, two UHPC piles ...


Stress Analysis Of Wood-Framed Low-Rise Buildings Under Wind Loads Due To Tornados, Nikhil Kumar Jan 2008

Stress Analysis Of Wood-Framed Low-Rise Buildings Under Wind Loads Due To Tornados, Nikhil Kumar

Retrospective Theses and Dissertations

Buildings in the "tornado alley" of the United States, an area where tornados occur most frequently, are built to withstand 3-sec wind speeds of 90 mph, whereas 90% of the tornados reported generate anywhere from 40 to 157 mph. At the same time, these codes are based mostly on studying the effects of straight line winds and not on tornado type winds on buildings, especially on low-rise, wood framed buildings which make up the majority of structures in the United States. Previous research at Iowa State University (ISU) includes extensive testing on a scaled down low-rise gable roof building model ...


The Development Of A Case Based Reasoning Tool For High-Speed Signalized Expressway Intersections In The State Of Iowa, Josh Nicholas Hinds Jan 2008

The Development Of A Case Based Reasoning Tool For High-Speed Signalized Expressway Intersections In The State Of Iowa, Josh Nicholas Hinds

Retrospective Theses and Dissertations

The safety of signalized expressway intersections has been the focus of prior research. These efforts have yielded results that were either inconclusive or required further investigation. This thesis presents the application of case-based reasoning to the issue. Similar intersections and crash reduction factors (CRFs) are used to establish expected crash performance for a candidate intersection. A spreadsheet based tool is developed that compares candidate intersections to these comparison sites. The tool uses expert opinions, attribute weights, and crash reduction factors to assist in the decision to signalize a site, to compare performance of existing signalized intersections to similar sites, or ...


Utility Cut Repair Techniques: Investigation Of Improved Utility Cut Repair Techniques To Reduce Settlement In Repaired Areas, Phase Ii, Kathlyn A. Videkovich Jan 2008

Utility Cut Repair Techniques: Investigation Of Improved Utility Cut Repair Techniques To Reduce Settlement In Repaired Areas, Phase Ii, Kathlyn A. Videkovich

Retrospective Theses and Dissertations

Trench maintenance problems are caused by improper backfill placement and construction procedures. This thesis is part of a multi-phase research project that aims to improve long-term performance of utility cut restoration trenches. The goal of this research is to improve pavement patch life and reduce the maintenance of the repaired areas. The objectives were to use field-testing data, laboratory testing data, and long-term monitoring (elevation survey and FWD testing) to suggest and modify recommendations from Phase I and to identify the principles of trench subsurface settlement and load distribution in utility cut restoration areas by using instrumented trenches. The objectives ...


Evaluation Of Bridges Implementing Innovative Materials And Design, Mark Thomas Giesmann Jan 2008

Evaluation Of Bridges Implementing Innovative Materials And Design, Mark Thomas Giesmann

Retrospective Theses and Dissertations

Concrete bridge decks exposed to harsh temperatures and a variety of deicing chemicals are suspect to deterioration caused by corrosion of the steel reinforcement. By removing the steel reinforcement within the concrete slab, the life expectancy and durability of the bridge deck can be expected to improve greatly [1]. Researchers at the Bridge Engineering Center at Iowa State University have researched, designed, and tested the first known bridge in the United States that has implemented a steel-free deck (SFD) system. The bridge deck consists of a fiber reinforced deck with no internal reinforcing steel that is composite with the steel ...


Evaluation Of An Anaerobic Granule Biosensor For Upset Early Warning Detection, Xi Jiang Jan 2008

Evaluation Of An Anaerobic Granule Biosensor For Upset Early Warning Detection, Xi Jiang

Retrospective Theses and Dissertations

In this study a porous pot reactor was used to simulate an activated sludge stage and an anaerobic granule biosensor (AGB), as an upset early warning system for activated sludge treatment process, was configured in a down-flow mode with a side-stream of the influent wastewater fed to the top. The hydraulic retention time (HRT) for the porous pot and AGB systems was 12 hours and 6 hours, respectively. The influent was made up of synthetic wastewater. In the first group of toxic loading tests, the prepared cupric chloride solutions were separately injected into both the porous pot and AGB systems ...


Production Of A New Wastewater Treatment Coagulant From Fly Ash With Concomitant So2 Removal From Flue Gas, Ling Li Jan 2008

Production Of A New Wastewater Treatment Coagulant From Fly Ash With Concomitant So2 Removal From Flue Gas, Ling Li

Retrospective Theses and Dissertations

Sulfur dioxide (SO2) is one of major air pollutants emitted from coal combustion. When it is emitted into the environment, it imposed many adverse health and environmental impacts, such as impairment of respiratory system, reduction of visibility and acid rain. Traditional sulfur dioxide removal technologies have the disadvantages disposal of large amount of by-products with low market value.;Fly ash, a by-product of coal combustion rich in iron and aluminum oxides and sodium chlorate as an oxidant were utilized in this project to produce a complex coagulant with the removal of sulfur dioxide in simulated flue gas. Conversion efficiency of ...


Evaluation Of Tire Derived Rubber Particles As Biofilter Media And Scale-Up And Design Considerations For The Static Granular Bed Reactor (Sgbr), Jaeyoung Park Jan 2008

Evaluation Of Tire Derived Rubber Particles As Biofilter Media And Scale-Up And Design Considerations For The Static Granular Bed Reactor (Sgbr), Jaeyoung Park

Retrospective Theses and Dissertations

Research demonstrated three different bioreactors to evaluate use of tire rubber as biofilm attachment media in bioreactors for wastewater treatment: aerobic biofilter, anoxic bioreactor, and a hybrid anaerobic static granular bed reactor (SGBR). In addition, owing to the results from non-toxicity to microorganism and good surface area for biofilm attachment, size distribution, chemical composition, scanning electron microscopy, and whole effluent toxicity analyses verify the potential of TDRP (tire derived rubber particles) usage for biofilm attachment media. The trickling filter system using chunk rubber (average diameter of approximately 3 cm) achieved 79.6-90.1% COD removal efficiency at organic loading rates ...


Concept Relation Extraction Using Natural Language Processing: The Crisp Technique, Mohammed Abdelrahman Al Qady Jan 2008

Concept Relation Extraction Using Natural Language Processing: The Crisp Technique, Mohammed Abdelrahman Al Qady

Retrospective Theses and Dissertations

Knowledge Management (KM) has become the focus of a lot of scientific research during the second half of the twentieth century as researchers discovered the importance of the knowledge resource to business organizations. Recent research developed ontology-based knowledge management systems (KMS) to provide a standardized reference for knowledge consistency. However, use of ontologies has been impeded by the difficulties encountered in building ontologies, especially difficulties in the knowledge acquisition stage. It is hypothesized that NLP tools can be usefully implemented to assist in the knowledge acquisition stage for ontology building in specific, and to develop effective KMS’s in general ...


Microwave Nondestructive Evaluation Of Aircraft Radomes, David Bennett Johnson Jan 2008

Microwave Nondestructive Evaluation Of Aircraft Radomes, David Bennett Johnson

Retrospective Theses and Dissertations

As the aviation industry continues to experience increased demand on maintenance turn-around time with decreased budgets, the airlines in particular seek advances in cost and efficiency for inspection technology. Such improvements not only increase aviation safety, but also lead to significant cost savings and avoidances. One particular inspection need is that of aircraft radomes, often found as the nosecone such as that seen in Figure 1.1, housing the plane's weather radar. This structure, fabricated out of low-loss/permittivity composite materials (such as fiberglass), must appear as "electrically transparent" as possible to the radar. Like a window to the ...


Performance-Based Seismic Analysis And Design Improvements Of Two Precast Concrete Structural Systems, Mohammad Ataur Rahman Jan 2008

Performance-Based Seismic Analysis And Design Improvements Of Two Precast Concrete Structural Systems, Mohammad Ataur Rahman

Retrospective Theses and Dissertations

This study focuses on the multiple-level seismic performance in terms of structural and non-structural damages of precast hybrid frame and jointed precast post-tensioned wall systems through dynamic analysis of precast buildings subjected to spectrum compatible ground motions of various intensities. The maximum transient interstory drift, residual interstory drift and floor acceleration are considered as acceptance criteria for evaluating seismic performance of these systems subjected by four levels of ground motions. Interstory drift and floor acceleration are directly related to structural and non-structural damages, respectively. Two dimensional non-linear finite element analytical models for hybrid frames and jointed wall systems used in ...


Anaerobic Membrane Bioreactor For The Treatment Of Low Strength Wastewater, Jae Ho Ho Jan 2007

Anaerobic Membrane Bioreactor For The Treatment Of Low Strength Wastewater, Jae Ho Ho

Retrospective Theses and Dissertations

This research investigated the fundamentals of anaerobic membrane bioreactor (AMBR) operated at low trans-membrane pressure (TMP) and cross-flow velocity (CFV) using poly-tetrafluoroethylene (PTFE) membrane for the treatment of low strength wastewater.;Specific methanogenic activity (SMA) test was used to examine the methanogenic activity profiles of suspended and attached sludge in AMBR treating synthetic municipal wastewater at 25 and 15°C. It was hypothesized that accumulated biomass on the membrane surface could act as a secondary membrane as well as a biofilm which removed chemical oxygen demand (COD) biologically. The results showed that attached sludge on the membrane surface had lower ...


Gis Modeling Of Urbanization Impacts On Natural Resources, Dakota County, Minnesota, Lan Wei Jan 2007

Gis Modeling Of Urbanization Impacts On Natural Resources, Dakota County, Minnesota, Lan Wei

Retrospective Theses and Dissertations

This research focused on the impacts of urbanization in natural resources and land-cover changes due to urban development in Dakota County, Minnesota. An existing planning guide, the 2030 Regional Development Framework (2030 RDF) for the Twin Cities Metro Area, was analyzed and employed as a reference in this research. Geographic information systems (GIS) technology was used to help determine characteristics of urban land-cover changes, such as population change, land cover changes, and the environmental impacts on natural resources caused by urban development. Furthermore, land suitability modeling was utilized to analyze possible future development, from the perspectives of urban expansion and ...


Solar Heating Of A Residential Building In Kazakhstan, Ernar Aidargazaevich Makishev Jan 2007

Solar Heating Of A Residential Building In Kazakhstan, Ernar Aidargazaevich Makishev

Retrospective Theses and Dissertations

A study of flat-type solar space heating for a residential building has been done. The study includes comparing of several solar radiation estimating methods. Computer simulation is written in Matlab. Full code is listed in the Appendix. The results show that flat-type solar collectors can perform well under the severe weather conditions and the radiation levels of Astana, Kazakhstan. However, the simulation of a solar space heating system compared to an electric resistance heating system showed that the solar heating system that is simulated cannot provide enough heating capacity to heat the building without 50% backup system. In addition, the ...


Evaluation Of A Structural Testing System, Anthony Samuelson Jan 2007

Evaluation Of A Structural Testing System, Anthony Samuelson

Retrospective Theses and Dissertations

According to the 2004 National Bridge Inventory, nearly 28% of Iowa's 25,000 bridges are rated as structurally deficient or functionally obsolete. Many of these structures are rated so by traditional visual bridge inspection and codified rating procedures. With many of these structures needing replaced or repaired, the problem is compounded by increasing bridge project costs and decreasing funding for such projects. A diagnostic tool is often necessary to accurately quantify the actual behavior and load carrying capacity of these deficient structures.;Iowa State University recently completed an evaluation of a commercially available diagnostic load testing system that combines ...


Use Of Ground Clay Brick As A Supplementary Cementitious Material In Concrete Hydration Characteristics, Mechanical Properties, And Asr Durability, Fatih Bektas Jan 2007

Use Of Ground Clay Brick As A Supplementary Cementitious Material In Concrete Hydration Characteristics, Mechanical Properties, And Asr Durability, Fatih Bektas

Retrospective Theses and Dissertations

The work presented in this Dissertation involves an effort to broaden sustainable applications (e.g., recycling waste material in concrete, reducing CO2 emissions in cement production) in construction industry. Finely ground brick obtained from demolished masonry was evaluated as a pozzolanic cementitious material in concrete. The hydration characteristics of this material and its effects on cement paste, mortar, and concrete mechanical properties, particularly on alkali-silica reaction deterioration was studied. Ground clay brick (GCB) was produced in the laboratory employing a ball mill. Chemical and physical properties comply with the designated ASTM standard that defines pozzolanic materials. The results of the ...


Influence Of Anaerobic And Anoxic Hydraulic Retention Time On Biological Nutrient Removal In A Membrane Bioreactor, Patrick Anderson Brown Jan 2007

Influence Of Anaerobic And Anoxic Hydraulic Retention Time On Biological Nutrient Removal In A Membrane Bioreactor, Patrick Anderson Brown

Retrospective Theses and Dissertations

Regulation of the discharge of biological nutrients into the environment continues to increase in order to protect sensitive bodies of water. One promising new technology is the membrane bioreactor, which combines the activated sludge process with membrane filtration. The focus of this study was to determine the best anaerobic and anoxic hydraulic retention time (HRT) for biological nitrogen and phosphorus removal. A randomized experimental design of fourteen different HRT runs was tested with the anaerobic HRT varying between 0.5 and 3 hours and the anoxic HRT varying between 1 and 5 hours. Essentially complete nitrification was achieved with an ...


Optimizing Portland Cement Concrete Mix Design To Environmental And Construction Variables With The Aid Of Computer Design Software, Sybil K. Reinert Jan 2007

Optimizing Portland Cement Concrete Mix Design To Environmental And Construction Variables With The Aid Of Computer Design Software, Sybil K. Reinert

Retrospective Theses and Dissertations

There is a need in the concrete industry to optimize the characteristics of concrete for construction. Concrete Mixture Performance Analysis System (COMPASS) is a computer-based program designed to help contractors and clients evaluate their concrete mix designs. COMPASS was used to evaluate the characteristics of four Iowa paving mixes. Paving projects were selected from areas of Iowa to incorporate the different aggregates and cement producers. The following paving projects were selected to evaluate COMPASS: Cass County (Hwy 71) in southwest Iowa, Sac County (Hwy 175) in central Iowa, Osceola County (Hwy 60) in northwest Iowa, and Wapello County (U.S ...