MS Theses - DO NOT EDIT
http://hdl.handle.net/10106/24847
2024-03-29T10:49:19ZEstimation of Suspended Sediment Concentration along the Lower Brazos River using Satellite Imagery and Machine Learning
http://hdl.handle.net/10106/31774
Estimation of Suspended Sediment Concentration along the Lower Brazos River using Satellite Imagery and Machine Learning
**Please note that the full text is embargoed until 8/1/2024** ABSTRACT: Suspended sediment transport in river basins is important for many water management planning activities to maintain safe drinking water for the community and maintenance of water quality and waterways for the ecosystem. Currently, the traditional way to measure suspended sediment effectively and reliably is by collecting field samples in the river body, which is very time consuming and only provide a point value of suspended sediment within the waterbody at the instant the sample was taken. This thesis focuses on developing models that estimate suspended sediment concentrations for the lower Brazos River using satellite imagery from publicly available data and machine learning methods. The use of optical properties such as satellite imagery and turbidity measurements have been gaining support recently and provide a more continuous record of suspended sediment concentrations and in the case of satellite imagery a spatial relationship once a model is developed. Historical samples of suspended sediment concentrations from the United States Geological Survey and Texas Commission on Environmental Quality and satellite imagery from Landsat Missions and Sentinel Mission 2 were utilized to develop models to estimate suspended sediment concentrations for the lower Brazos River. Models used in this thesis to accomplish this goal include support vector machines, artificial neural networks, extreme learning machines, and exponential relationships. In addition, flow and depth measurements from the United States Geological Survey were used to develop rating curves to estimate suspended sediment concentrations for the Brazos River as a baseline comparison of the models that used satellite imagery to estimate suspended sediment concentrations. Models were evaluated using the Taylor Diagram analysis on the test data set developed for the Brazos River data. Sixteen of the models using satellite imagery as inputs that were developed for this thesis performed with a coefficient of determination R2 above 0.69 with the three best performing models having an R2 of 0.83 to 0.85. One of the best performing models was then applied estimate suspended sediment concentrations before, during, and after Hurricane Harvey to evaluate Hurricane Harvey’s impact to the sediment dynamics along the lower Brazos River and the model’s ability to achieve this goal. The models that used satellite imagery developed for this thesis were also evaluated on the San Bernard River to test their ability outside of the Brazos River; however, all models achieved an R2 below 0.04. In addition, the importance of input variable to estimate suspended sediment concentrations were evaluated using the principal component analysis which determined that the NIR, red, and green bands were significant to achieve this goal. This was confirmed with the best performing models developed incorporating the Red-Green Ratio as an input.
2023-08-23T00:00:00ZASSESSING THE TREATMENT EFFICIENCY OF EXPANDED SHALE AS A FILTER MEDIUM IN A BIOSWALE
http://hdl.handle.net/10106/31754
ASSESSING THE TREATMENT EFFICIENCY OF EXPANDED SHALE AS A FILTER MEDIUM IN A BIOSWALE
**Please note that the full text is embargoed until 08/01/2024** This thesis presents a laboratory investigation focusing on the use of expanded shale as a filter media in bioswales. Bioswales are known for their effectiveness in improving water quality by removing pollutants such as total suspended solids (TSS) and turbidity. While conventional filter media with rocks, sand, and mulches have been utilized in bioswales to enhance infiltration capacity, the potential of expanded shale as an engineered media has not been thoroughly assessed and documented.
The study conducted a series of thirty experiments involving three different flow conditions to mimic typical Best Management Practices (BMP) applications. The primary focus was on investigating the efficiency of the swale constructed with expanded shale in removing TSS and turbidity, which are key indicators of stormwater pollutants.
The experiments were carried out in a rectangular flume measuring 15 feet in length and 4 feet wide, filled with expanded shale media with thicknesses of 6 inches and 4 inches.
The study presented the performance of two different types of expanded shale with varying gradations, fine and coarse sizes. Additionally, the impact of influent concentration on the expanded shale media's effectiveness was examined, and two scenarios representing bioswales with and without an underdrain system were studied.
The results demonstrated that expanded shale was highly effective in removing both TSS and turbidity under all tested conditions. The mean weighted average removal efficiency of TSS was found to be 42%, 43%, and 68% for the middle section of the channel, overflow, and infiltered flow, respectively, with a range of 20% to 75%, 19% to 75%, and 55% to 82%. Similarly, mean weighted turbidity removal was 17%, 15%, and 40% for the middle section, overflow, and infiltered flow, respectively, with a range of -4% to 43%, -7% to 49%, and 22% to 61%. Approximately 42% of TSS and 17% of turbidity removal occurred within the first half of the flow length.
Due to the sedimentation process, coarser particles were observed to settle along the flow length of the flume. However, the particle gradation of the suspended sediment remained constant with time at a specific sampling location.
Overall, the results indicated that greater filter media thickness, coarser expanded shale materials, and lower inflow rates consistently resulted in higher removal efficiency. Moreover, the influent concentration did not significantly impact the treatment efficiency of the expanded shale media.
This study highlights the promising potential of expanded shale as an effective filter media in bioswales for enhancing water quality by removing pollutants such as TSS and turbidity.
2023-08-21T00:00:00ZCOMPARATIVE MECHANICAL PROPERTY EVALUATION OF ULTRA-HIGH-PERFORMANCE CONCRETE REINFORCED WITH HIGH-STRENGTH STEEL STRAIGHT AND HOOKED FIBERS
http://hdl.handle.net/10106/31737
COMPARATIVE MECHANICAL PROPERTY EVALUATION OF ULTRA-HIGH-PERFORMANCE CONCRETE REINFORCED WITH HIGH-STRENGTH STEEL STRAIGHT AND HOOKED FIBERS
This study investigates the tensile properties and ductility of ultra-high-performance concrete (UHPC) reinforced with high-strength steel hooked fibers with a tensile strength of 445 ksi (3,070 MPa) and compares its tensile performance to that of UHPC reinforced with commonly used high-strength smooth steel microfibers with a tensile strength of 2,160 MPa (313 ksi). The research is based on a proprietary mix developed at the University of Texas at Arlington and investigates the mechanical properties of UHPC with varying fiber volume fractions of 1.5%, 2%, 2.25%, and 2.4%. The experimental results indicate that UHPC reinforced with high strength hooked fibers generally exhibits superior tensile strength and ductility compared to UHPC reinforced with straight, smooth steel fibers, except for the 1.5% fiber volume fraction. Moreover, this study examines the improvement of UHPC flowability through the inclusion of specific constituents such as spherical-shaped silica fume, sands, or fly ash. Enhancing flowability is crucial for facilitating the production of UHPC-based SIFCON (UHP-SIFCON). Additionally, the study investigates the influence of varying curing regimes on UHPC mechanical properties by examining factors like heat treatment temperature (60°C and 90°C) and delay time for heat treatment (immediately after casting or after a 24-hour delay). To determine the tensile strength of UHPC, direct tensile test (DTT) is performed, complemented by the four-point loading flexure test and double punch test (DPT) for comparison purposes. Furthermore, analytical investigations are performed to evaluate the accuracy of the assumptions in the ASTM 1609 beam test standard, while the DPT results are confirmed with the DTT results to ascertain their reliability in measuring tensile response. The outcomes of this study will contribute to the understanding of the mechanical bonding effect of hooked fibers on the tensile performance of UHPC and UHP-SIFCON, as well as contribute to the development of a more reliable testing method for evaluating UHPC properties.
2023-08-15T00:00:00ZINVESTIGATION AND PROPOSED REMEDY OF VIBRATION PROBLEM IN INDUSTRIAL CRANE SYSTEM DUE TO HUMAN OPERATION
http://hdl.handle.net/10106/31674
INVESTIGATION AND PROPOSED REMEDY OF VIBRATION PROBLEM IN INDUSTRIAL CRANE SYSTEM DUE TO HUMAN OPERATION
A recent investigation of a crane system began when a facilities manager reported a runway beam under-going torsional vibration during operations. The investigation revealed the runway beam’s twisting was caused by resonance vibration due to “inching” of the crane hoist. A Fourier spectrum analysis revealed that one of the harmonic frequencies of this rhythmical motion coincided very close to the natural frequency of the crane system. The runway beam, although met strength requirements, failed to meet serviceability criteria due to the resonance vibration. Resonance vibration issues due to human activity in crane operation (inching, sway, etc.) is often encountered by engineers when designing crane runways. These issues are even more familiar in long-span crane runways where limited bracing opportunities exist. While vibration resonance issues, of all modes, may be known to many designers of crane structures, the time required to run an in-depth dynamic analysis is usually not economical for such a simple structure. Possible critical vibration issues coupled with the inability to perform an in-depth analysis requires design engineers to use very conservative design recommendations regarding vibration. The few design recommendations found in current standards are very broad and offer little-to-no commentary, and the application of such design recommendations may or may not support a critical vibration mode. The resulting overdesign may reinforce a vibrational mode which is not necessarily an object of concern. The cost associated with the overdesign could have possibly been directed towards a more vibrational sensitive mode. This study first investigated the cause of the resonance vibration. Secondly, through extensive finite element analyses (FEA), a practical solution is recommended. Lastly, using the FEA results, alongside current standards, a set of design equations are formulated to aid in future crane runway vibration design in addition to the limited vibration research.