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Articles 1 - 17 of 17
Full-Text Articles in Engineering
Predictive Maturity Of Inexact And Uncertain Strongly Coupled Numerical Models, Ismail Farajpour
Predictive Maturity Of Inexact And Uncertain Strongly Coupled Numerical Models, Ismail Farajpour
All Dissertations
The Computer simulations are commonly used to predict the response of complex systems in many branches of engineering and science. These computer simulations involve the theoretical foundation, numerical modeling and supporting experimental data, all of which contain their associated errors. Furthermore, real-world problems are generally complex in nature, in which each phenomenon is described by the respective constituent models representing different physics and/or scales. The interactions between such constituents are typically complex in nature, such that the outputs of a particular constituent may be the inputs for one or more constituents. Thus, the natural question then arises concerning the validity …
Seismic Site Coefficient Model And Improved Design Response Spectra Based On Conditions In South Carolina, Shimelies Aboye
Seismic Site Coefficient Model And Improved Design Response Spectra Based On Conditions In South Carolina, Shimelies Aboye
All Dissertations
A new seismic site coefficient model is developed from the results of over 60,000 total stress, one-dimensional equivalent ground response simulations assuming conditions in South Carolina. Computed site coefficients ( F ) are plotted versus average shear wave velocity in the top 30 m (VS30 ) and grouped by location, spectral acceleration (Soutcrop ) and spectral period. Locations considered in the Coastal Plain include Aiken, Charleston, Columbia, Florence, Lake Marion, Myrtle Beach, and the South Carolina side of Savannah. Locations considered in the Piedmont include Columbia, Greenville, Greenwood, and Rock Hill. In all the plots of …
Application Of Image Processing And Finite Element Analysis In Modeling Chloride Diffusion In Concrete, Arash Razmjoo
Application Of Image Processing And Finite Element Analysis In Modeling Chloride Diffusion In Concrete, Arash Razmjoo
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Utilizing numerical simulation models to predict the long-term mechanical and transport behavior of concrete structures is becoming increasingly popular. The majority of these models have been developed using laboratory test data that consider concrete as a homogeneous material with spherical aggregates. These models could not be a represented of real concrete because it has no primitive shaped aggregate besides that the porosity size and distribution varies from point to point. In this study a novel method for more accurate prediction of the chloride diffusion in concrete was developed. A general framework of the quantitative computed tomography (QCT) and finite element …
Assessing Potential Environmental Impacts According To Probable Patterns Of Switchgrass Adoption In The Southeastern Us, Benjamin Sharp
Assessing Potential Environmental Impacts According To Probable Patterns Of Switchgrass Adoption In The Southeastern Us, Benjamin Sharp
All Dissertations
To assess the overall net impact of an emerging technology, life cycle assessment (LCA) must be accompanied by projections of adoption. Diffusion of innovation research provides tools that incorporate economic and social variables to explain and forecast integration of technologies. A switchgrass-to-ethanol case study for the southeastern U.S. is used to demonstrate methods for gauging aggregate environmental effects of an emerging energy technology. Before applying diffusion concepts, breakeven capacities are calculated for land in row crops, hay, pasture and marginal land. Breakeven curves are generated to provide upper bounds to switchgrass adoption over a range of farm-gate prices. The amount …
Optimization Of Porous Pavement Mixtures Based On Aggregate Structure, Andrew Neptune
Optimization Of Porous Pavement Mixtures Based On Aggregate Structure, Andrew Neptune
All Dissertations
Porous pavements are sustainable features that are used to help manage the quantity and quality of stormwater runoff. These pavements may include porous asphalt, permeable interlocking concrete pavers and pervious concrete. Since pavements that are purposefully designed to drain water through their matrix are relatively new, contractors and engineers are faced with various challenges such as improper design and installation, poor workability, and excessive finishing which may lead to clogged pores. Therefore, this study on porous pavements examined pervious concrete mixtures to evaluate an optimization process for the preparation of porous pavement mixtures based on aggregate structure to meet desired …
Robust Design Optimization: Ensuring Robustness Against Uncertainty In Structural Design, Zhifeng Liu
Robust Design Optimization: Ensuring Robustness Against Uncertainty In Structural Design, Zhifeng Liu
All Dissertations
In structural design, if robustness is overlooked in design process, the acquired design is likely to have large variation in its performance due to uncertainties. In that there is no design specification that explicitly considers the robustness against such uncertainties, this dissertation elucidates design methodologies for use in selecting the optimal design parameters to minimize the effect of the hard to reduce or irreducible uncertainties on structural performance, i.e., maximizing the robustness. However, due to limited resources, structural designs are also constrained by available resources and budget. Consequently, in that a tradeoff relationship exists between the robustness and cost (i.e. …
Development Of A Rating System To Measure The Vulnerability Of Residential Homes To Natural Hazards, Corey Cattano
Development Of A Rating System To Measure The Vulnerability Of Residential Homes To Natural Hazards, Corey Cattano
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Hurricanes and tropical storms continue to damage the United States coastline where population migration increases and tourism thrives. Extended dry spells, high winds, and hot summers in the Mountain and Pacific West regions promote ideal conditions for seemingly uncontrollable wildfires. Additionally, the increased frequency of unstable climate conditions foretells signs of Mother Nature not letting up. With recent events such as Superstorm Sandy and the Waldo Canyon wildfires in mind, there is a strong need to improve hazard mitigation techniques in residential homes and encourage resilient building methods. Research within this field is challenging due to the lack of descriptive …
Renovation Of Ammonia Contaminated Produced Water Using Constructed Wetlands, Donald Beebe
Renovation Of Ammonia Contaminated Produced Water Using Constructed Wetlands, Donald Beebe
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Pilot-scale wetland treatment systems were designed and constructed to evaluate renovation of simulated oilfield produced water contaminated with ammonia (20 mg/L ammonia-N). A process-based pilot-scale constructed wetland was designed to meet specific biogeochemical conditions for conversion of ammonia to nitrogen gas through microbial nitrification and denitrification. The process-based constructed wetland treated the simulated produced water to meet stringent discharge requirements (less than 1.2 mg/L ammonia-N). Clinoptilolite, a zeolite mineral, was evaluated for use in constructed wetlands to increase ammonia sorption and nitrification activity. Clinoptilolite increased wetland ammonia sorption capacity and served as a microbial carrier for nitrifying bacteria when ranges …
Optimizing Scm Proportions To Meet Multiple Performance Characters Of Ternary Concrete Mixtures Using Simplex-Centroid Design And Analysis Techniques, Sujay Math
All Dissertations
High performance concrete mixtures often contain multiple cementitious components. Among these, cement is the most expensive in addition to having a higher carbon footprint. Life cycle assessment of cement production reveals that the cement content is the most important factor in determining a concrete mixture's embodied energy and carbon footprint. Compressive strength, an important property of concrete, is directly related to the quantity of cement used in the mixture. However, higher quantities of cement lead to durability issues. The increased concerns about the durability of concrete over the past decade have increased focus on improving the long-term performance of concrete …
Development And Evaluation Of An Intelligent Transportation Systems-Based Architecture For Electric Vehicles, Zhiyun Li
All Dissertations
The rapid development of increasingly complex in-vehicle electronics now offers an unprecedented level of convenience and versatility as well as accelerates the demand for connected driving experience, which can only be achieved in a comprehensive Intelligent Transportation Systems (ITS) technology based architecture. While a number of charging and range related issues continue to impede the Electric Vehicle (EV) market growth, integrating ITS technologies with EVs has the potential to address the problems and facilitate EV operations. This dissertation presents an ITS based vehicle infrastructure communication architecture in which abundant information can be exchanged in real time through vehicle-to-vehicle and vehicle-to- …
Hydraulic Impact Of Porosity Distribution And Hydrologic Characterization Of Porous Pavements, William Martin
Hydraulic Impact Of Porosity Distribution And Hydrologic Characterization Of Porous Pavements, William Martin
All Dissertations
This research focused on the hydrologic characterization of porous pavement and pavement properties that can affect its hydraulic behavior. The first of these properties investigated was the presence of a vertical porosity distribution which can significantly impact the infiltration rate. A method utilizing image analysis was tested and experimentally verified. The representative elemental area (REA) was needed for this imaging method and was found to be 83.9 cm2 (13 in2). To convert the porosity distribution into a permeability distribution the relationship between porosity and permeability was found using homogenous samples. From the resulting permeability distribution an effective permeability was found …
Miniature Concrete Prism Test - A New Test Method For Evaluating The Asr Potential Of Aggregates, The Effectiveness Of Asr Mitigation And The Job Mixture, Enamur Latifee
All Dissertations
Existing test methods to characterize ASR potential of aggregates and mitigation ability of supplementary cementing materials such as the Accelerated Mortar Bar Test (AMBT) and the Concrete Prism Test (CPT) are widely accepted in the industry. Although, the AMBT is a rapid test, the results from this test can be unreliable, particularly with certain types of aggregates. The CPT is considered as a more reliable test; however, the duration of this test method renders it impractical for routine usage in the industry to screen deleterious materials or inefficient ASR mitigation measures. This research presents a new test method-Miniature Concrete Prism …
Development Of An Environmental And Operational Impact Assessment Framework For Connected Vehicle Technology Supported Alternative Fuel Vehicles, Parth Bhavsar
All Dissertations
The efforts of US automobile manufacturers to introduce Alternative Fuel Vehicles (AFVs) to the automobile market, and reduce fossil fuel dependency are changing the energy consumption scenario of the US transportation network. The evolution in Connected Vehicle Technology (CVT) is further accelerating the vision of a safe and sustainable transportation system for the 21st century. However, before such system can be an actuality to meet future US transporation needs, a new generation of traffic micro-simulation tools must be developed to evaluate connected vehicle technologies that can support AFVs in the transportation network.
This research focused on developing an evaluation framework …
Freeze-Thaw Durability Of Portland Cement Concrete Due To Addition Of Crumb Rubber Aggregates, Shubhada Gadkar
Freeze-Thaw Durability Of Portland Cement Concrete Due To Addition Of Crumb Rubber Aggregates, Shubhada Gadkar
All Dissertations
Ground tire rubber also known as crumb rubber has been widely used in asphalt concrete over the past several years due to its ability to improve temperature susceptibility of asphalt binders and enhance the performance of asphalt pavements. However, its inclusion in portland cement concrete is comparatively recent and more research is needed before adopting it as a regular construction material. Past research has shown that while addition of rubber aggregates in concrete reduces its compressive, tensile and flexural strengths, but is useful in improving durability properties as freeze-thaw resistance due to the ability of crumb rubber to generate an …
Vehicle-Infrastructure Integration Enabled Plug-In Hybrid Electric Vehicles For Energy Management, Yiming He
Vehicle-Infrastructure Integration Enabled Plug-In Hybrid Electric Vehicles For Energy Management, Yiming He
All Dissertations
The U.S. federal government is seeking useful applications of Vehicle-Infrastructure Integration (VII) to encourage a greener and more efficient transportation system; Plug-in Hybrid Electric Vehicles (PHEVs) are considered as one of the most promising automotive technologies for such an application. In this study, the author demonstrates a strategy to improve PHEV energy efficiency via the use of VII. This dissertation, which is composed of three published peer-reviewed journal articles, demonstrates the efficacies of the PHEV-VII system as regards to both the energy use and environmental impact under different scenarios.
The first article demonstrates the capabilities of and benefits achievable for …
Incorporating Natural Hazard Resistance Into The Life Cycle Assessment Framework, Jeffery Plumblee
Incorporating Natural Hazard Resistance Into The Life Cycle Assessment Framework, Jeffery Plumblee
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Hazard resistant building materials are not adequately represented by current LCA approaches, which do not account for environmental benefits of the avoided losses (e.g. avoided waste, avoided materials for repairs) promised by hazard resistant materials. The goal of this study was to encourage a more complete understanding of materials' environmental impacts by developing a framework to include hazard related damages in LCA.
Catastrophe modeling is a well-developed tool used by the insurance industry to assess the probability of hazard and quantify related impacts. These models were studied to identify required input data as well as the format of output results. …
Aerosol Delivery As A Method For Enhancing Remedial Application In Contaminated Vadose Zones, Richard Hall
Aerosol Delivery As A Method For Enhancing Remedial Application In Contaminated Vadose Zones, Richard Hall
All Dissertations
Remediation of contaminated vadose zones is often hindered by an inability to effectively distribute liquid- or solid-phase amendments. Many amendment-based approaches, such as bioremediation, chemical oxidation, and reactive barriers have been successful in saturated formations. However, these remedial approaches have seen limited application in unsaturated materials, largely because of difficulties delivering amendments.
Aerosol delivery is a promising approach for distributing amendments in contaminated vadose zones. The amendments are aerosolized, creating a cloud of micron to sub-micron-scale liquid droplets held suspended in a gas by Brownian motion. During injection into porous media, the aerosol particles are transported along with the gas …