PhD Dissertations - DO NOT EDIThttp://hdl.handle.net/10106/248482024-03-28T17:30:31Z2024-03-28T17:30:31ZTESTING AND EVALUATION OF POLYMERIC SPRAY APPLIED PIPE LINING IN PRESSURE PIPE APPLICATIONShttp://hdl.handle.net/10106/318032024-02-13T20:53:12Z2023-08-30T00:00:00ZTESTING AND EVALUATION OF POLYMERIC SPRAY APPLIED PIPE LINING IN PRESSURE PIPE APPLICATIONS
**Please note that the full text is embargoed until 08/01/2024** Pressure pipes are an important component of pipe infrastructure for water mains, distribution lines, fuel and gas piping, process piping, building services piping, and many more. Various material types are available to be used in the pressure pipes, in which metal pipes are ubiquitous for high pressure applications, plastic pipes are also commonly used, and sometimes concrete pressure pipes are used in large diameter pipes for its economic factors. Most of these pipes currently in service are 50 to 60 years old, and some are 100 years old. Furthermost pipelines have exceeded their design life and are continuously deteriorating to the catastrophic situations; thus, there is an urgent need to develop a method or technology to restore the existing underground pipeline and infrastructure.
Spray applied pipe lining (SAPL) is a trenchless pipe renewal technology that can combat the issue of pipe aging and failure. SAPL is applied inside a pipe for either corrosion prevention or load-bearing capacity enhancement of the existing pipe by creating a new stand-alone pipe within the host pipe. Adding to the structural capabilities of SAPL, in some cases, its application also improves the hydraulic flow capacity of the pipelines by providing a smooth internal surface profile, even considering the application decreases the internal diameter.
This dissertation presents the detailed testing and evaluation of structural and hydraulic properties of the polymeric liner material in pressure pipes. The testing plan includes full-scale laboratory tests of short-term hole-spanning, vacuum pressure, pressure integrity, and hydraulic flow. The short-term hole spanning test results on 30-inch pipe diameter samples determined the hole-spanning capacity of the SAPL when designed as semi-structural. The lining system was tested for a pressure resistance of up to 500 psi. The vacuum pressure test determined the vacuum load resistance of the lining system. The pressure integrity test on 8-inch pipe diameter samples determined the pressure resistance of the liner at extreme temperature conditions when designed as fully structural, i.e., with no support from the host pipe.
Lastly, the hydraulic flow test was critical to determine the effect of liner installation on improving the flow characteristics of a 6-inch lined pipe sample, though the liner decreases the internal diameter. The head loss of the lined pipe was compared with a moderately corroded pipe in a turbulent flow regime, and the results showed a reduction in the head loss of the lined pipe when compared with a moderately corroded pipe. Furthermore, the experimental results provided the design methodologies and validated the design equations for applying SAPL in pressure pipes.
The recommendations for future research studies are provided to test the lining system when designed as semi-structural and fully structural at different pipe diameters, with different thicknesses, and at varied temperatures. These test results will help evaluate the material's performance under different conditions of host pipes, environment, and loading.
2023-08-30T00:00:00ZINVESTIGATION ON THE IMPACTS OF LAND SUBSIDENCE AND URBANIZATION ON FLOOD INUNDATION IN TEXAShttp://hdl.handle.net/10106/318012023-11-09T22:34:41Z2023-08-25T00:00:00ZINVESTIGATION ON THE IMPACTS OF LAND SUBSIDENCE AND URBANIZATION ON FLOOD INUNDATION IN TEXAS
**Please note that the full text is embargoed until 08/01/2024** Floods, being a prevalent and catastrophic natural hazard, have resulted in enormous losses to human lives and properties all over the world. Hence, there is a pressing need to enhance urban resilience and to improve emergency response capacities in order to mitigate the risks posed by flood hazards. Many models have been developed by engineers to simulate and examine the hydrologic and hydraulic responses to the changes within the physical environment. However, there are still knowledge gaps in advancing the understanding of the H&H behavior and hydrodynamics modeling performance. This doctoral study aims to help bridge such gaps via assessing the impacts of land subsidence and urbanization on flooding. The findings of this research can provide valuable insights into understanding the changes of flood inundation results regarding land subsidence and urbanization, which can assist engineers and stakeholders in further research, decision making and flood emergency responses.
2023-08-25T00:00:00ZBreaking the Lignin Barrier with Termite TAV5 Treatment Technology (T4): Biopower and Biofuel from Agricultural Wastehttp://hdl.handle.net/10106/317972024-02-05T16:18:27Z2023-08-23T00:00:00ZBreaking the Lignin Barrier with Termite TAV5 Treatment Technology (T4): Biopower and Biofuel from Agricultural Waste
Bioenergy obtained from anaerobic digestion of lignocellulose biomass is one of the promising candidates to help move towards a fossil fuel free future. Agriculture waste has up to 90% lignocellulose content, and the eight leading US crops produce over 500 million tons of residue each year. Unfortunately, lignin is resistant to microbial attack under low oxygen conditions which normally occur in anaerobic digesters, and it often shields lignocellulose components (cellulose and hemicellulose) from decomposition as well. Traditional physical/chemical methods for destroying lignin are typically costly due to energy and chemical requirements and can create toxic intermediates (Rahimi et al., 2020).
Termites are commonly known for their ability to degrade wood, which contains high levels of lignin; microorganisms present in the hindgut of termites are responsible decomposition of lignin in wood. TAV5 (Termite Associated Verrucomicrobia) is the fastest-growing microorganism isolated from the hindgut of the Reticulitermes flavipes termite, the most widespread subterranean termite in North America. Its genome contains genes associated with methylotrophic competency which code for enzymes that structurally modify lignin (Kotak et al., 2015). TAV5 has been found to degrade lignin in anaerobic conditions, which is quite unique since most of the pathways for biologically degrading lignin are aerobic. The overall goal of our research is to use TAV5 to destroy lignin and boost methane production from agriculture waste. Specific objectives are:
1. To determine optimal conditions for efficiently growing TAV5 in large volumes for field seeding of waste.
2. To determine the optimal addition of TAV5 to enhance methane production from agricultural wastes.
3. To conduct life-cycle environmental and economic assessments of biogas produced from agricultural waste using T4 Technology, compared to baseline technologies (biogas produced without T4 Technology and fossil fuels).
To accomplish the first objective, lab tests were conducted to find growth of TAV5 at different temperatures. Afterwards TAV5 was grown aerobically and anaerobically, and growth curves were developed and verified by using the cell count procedure. To accomplish the second objective, batch-scale reactors (125 mL) with four kinds of agricultural waste (rice straw, corn stover, rice husk and wheat straw) were used to determine the optimal ratios of TAV5 to anaerobic digester (AD) microorganisms to decompose waste and produce methane. Based on the results from batch-scale tests, life cycle analyses were conducted. POWER Tool was used to calculate costs and emissions associated with all the phases of life cycle. Estimates were based on a 20-year life of digester and 2% interest rate was used for cost analysis.
It was found that TAV5 shows limited growth over 37oC and grows more quickly in aerobic conditions, which are less costly. Batch reactors showed that the optimal ratio between TAV5 and WRRF sludge is 0.3 for corn stover and rice straw, 0.2 for wheat straw and 0.6 for rice husk. A higher ratio of TAV5 to WRRF sludge was needed for rice husk, which could be because it has a higher lignin content compared to other wastes used in this research, or possibly because rice husk was not ground, whereas the other waste streams were ground to have smaller particle size. No correlation was found between the lignin values of the other wastes and the TAV5 ratio, nor between the lignin values and the increase in methane production. Life cycle showed that the revenue generated by extra electricity production more than offsets the cost of growing TAV5. Rice straw showed the highest avoided cost due to higher increase in methane generation, whereas wheat straw showed the lowest increase in methane generation, thus lower avoided cost. Seeding digesters with TAV5 reduced emissions of carbon dioxide and criteria pollutant (NOx, SO2) emissions, since the increased biogas production could be used to produce cleaner electricity than the average electricity from the power grid. However, VOC emissions increased because biogas itself has a high VOC content (around 50% methane). Rice straw showed the highest reduction in NOx, PM, SO2 and CO2 emissions because it generates the highest amount of methane, which in turn produces more clean electricity. Overall, the results show that seeding existing farm digesters with TAV5 will result in higher revenues and lower emissions, making the agriculture sector more sustainable.
2023-08-23T00:00:00ZANALYTICAL AND EXPERIMENTAL OF ELECTROMAGNETIC WAVE PROPAGATION EFFECT ON MOISTURE AND CORROSION IN AN INHOMOGENEOUS MEDIUMhttp://hdl.handle.net/10106/317942023-11-09T22:36:04Z2023-08-23T00:00:00ZANALYTICAL AND EXPERIMENTAL OF ELECTROMAGNETIC WAVE PROPAGATION EFFECT ON MOISTURE AND CORROSION IN AN INHOMOGENEOUS MEDIUM
**Please note that the full text is embargoed until 08/01/2024** This dissertation presents electromagnetic wave studies for infrastructure. The research contributes to a comprehensive understanding of electromagnetic wave propagation in moisture and provides insights into corrosion detection and monitoring in reinforced concrete infrastructure. Three major studies are performed to: 1) understand the multiple wave scattering in inhomogeneous moisture medium, 2) validate the experimental reflection through analytical finite difference time domain simulations with experimental measurements, and 3) evaluate the electromagnetic wave responses in the early stage and post stage corrosion experimentally, and 4) develop rapid corrosion monitoring methodology for field applications by employing cutting-edge electromagnetic wave image processing as refer to as 3-dimensional ground-penetrating radar (3DGPR) system.
First, the propagation of electromagnetic (EM) waves in a moisture medium is influenced by various key factors, including the dielectric constant, conductivity, and magnetic/electrical permeability. However, the majority of literature studying EM waves in multiple mediums tends to place a greater emphasis on the analysis by the dielectric constant This study of moisture mediums focuses on the importance of the dielectric constant and conductivity, as they play a significant role in EM wave behavior. In the experimental approach, the EM wave response of inhomogeneous moisture mediums undergoing a transition from a wet to a dry state over the course of a day effectively simulates the shift from saturation to drier conditions. To validate the results, EM wave frequency analyses obtained by these moisture mediums were compared with the results of numerical simulations using the finite difference time domain method, alongside moisture weight measurements. By incorporating a comprehensive approach, a deeper understanding of EM wave propagation in moisture mediums and its practical implications. This research will contribute to advancements in technology and offer valuable insights into the behavior of EM waves in various applications.
Second, in this study, numerical models are employed with an advanced computation analysis, specifically utilizing the finite difference time domain method based on Yee cell theory and Taylor series. These models are designed to replicate the experimental setup used in the initial study. To ensure comparable evaluations, the numerical model incorporates a similar antenna source and accounts for the inhomogeneity of the medium. To verify the accuracy of the numerical model, the antenna's response is validated against the experimental data obtained from the 1600MHz antenna in an air medium. The results from these numerical simulations demonstrate a frequency analysis pattern that closely resembles the experimental EM wave frequency pattern, showcasing the model's effectiveness in capturing the specific antenna behavior and moisture variation within the medium
Third, the extent of corrosion is predominantly influenced by the amplitude response of the EM wave signals. In pursuit of a deeper understanding and analysis of the corrosion process, conducted experimental accelerated corrosion tests on concrete rebar samples in the laboratory. To verify the different corrosion stages, utilized half-cell potentials and surface resistivity measurements. Additionally, radar signals were periodically collected over the course of the experiment for the concrete samples. The EM wave analysis revealed significant variations in both amplitude and frequency during the early and post-corrosion stages. To further validate the findings, employed simulation models were developed using the FDTD method, facilitating a thorough comparison with the experimental data. Additionally, the recorded current and voltage data from the accelerated concrete samples were utilized to comprehensively study the corrosion rate.
Finally, a cutting-edge 3DGPR system was developed and demonstrated for rapid bridge deck inspection. The primary purpose of using the 3DGPR system was to identify potential areas of corroded rebar by employing multiple 1600MHz antennas. The novelty of this system lies in its ability to rapidly collect data with a distance tracking system and a bridge data mapping algorithm. Through two field studies of bridge inspection, I effectively utilized the 3DGPR system to provide comprehensive insights into the scanned bridge area. The bridge data mapping algorithm employed in the system enables us to generate a 2D interpolation map highlighting potential reinforcement corrosion areas across the scanned bridge region. This mapping technique offers valuable visual information and aids in the assessment of the bridge's structural integrity. By integrating these multiple approaches, aim to enhance the robustness of the research findings and gain a more comprehensive understanding of the corrosion process in concrete structures.
2023-08-23T00:00:00Z