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Item Analysis and Evaluation of the Pedestrian Hybrid Beacon in School Zones(North Dakota State University, 2010) Bittner, Michael HowardMeeting dual objectives of pedestrian safety and motorist convenience at pedestrian crossings in school zones is an important and continuing challenge for all local communities. Pedestrian safety is influenced by pedestrian delays as well as motorist compliance of controls. Motorist convenience is influenced by the delay experienced by drivers. Conventional crosswalk control devices such as marked crosswalks and pedestrian signals are not always adequate or efficient in balancing these two crucial but conflicting objectives. The 2009 edition of the Manual on Uniform Traffic Control Devices (MUTCD) has paved the way for the use of a brand new crosswalk control device known as the pedestrian hybrid beacon (PHB). Previous research has provided evidence of this device's effectiveness in the area of motorist compliance and reduced motorist delay compared to traditional pedestrian signals. No prior research has been conducted on the PHB in the school zone context or on children pedestrians in general. This research has two objectives. The first objective was to analyze MUTCD Warrant 5 standards, which are designed for pedestrian signals in school zones, and the new PHB standards. This analysis will use pedestrian volume, vehicle volume, and gap availability on different test locations to conduct a comparative analysis of the two sets of standards. The purpose of this objective is to determine the transferability of the new MUTCD PHB standards in the school zone context. The second objective of this research was to evaluate three crosswalk control devices; marked crosswalks, pedestrian signals, and PHBs, for their ability to effectively address pedestrian safety and motorist convenience at school crossings. It was found that the PHB performed significantly better than traditional marked crosswalks but not markedly different than conventional pedestrian signals in the ability to balance the objectives of pedestrian safety and motorist convenience. The absence of improvements in performance of the PHB when compared to the pedestrian signal can be attributed to the fact that only 8.8% of motorists correctly utilized the PHB at the test location in Fargo, North Dakota. The most significant contribution of this thesis was finding that the current PHB standards in MUTCD are not transferable to the school zone context. For PHBs to be considered a viable option for engineers designing and controlling school crosswalks, it is essential that the MUTCD have school zone specific standards or guidance. The analysis carried out in this research provides insights into how such standards can be established and applied.Item Alginate Encapsulated Nanoparticle-Microorganism System for Trichloroethylene Remediation(North Dakota State University, 2012) Shanbhogue, Sai SharanyaNanoscale zero-valent iron (NZVI) particles were encapsulated in calcium alginate capsules for application in environmental remediation. TCE degradation rates for encapsulated and bare NZVI were similar indicating no adverse effects of encapsulation on degradation kinetics. Microorganisms were separately encapsulated and used along with encapsulated NZVI and co-encapsulated in calcium alginate capsules. Batch experiments were performed to test the efficacy of the combined iron-Pseudomonas sp. (PpF1) system. The combined system removed 100% TCE over the first three hours of the experiment followed by 70% TCE removal post TCE re-dosing. Complete reduction of TCE was achieved by NZVI between 0-3 h and the second phase of treatment (3-36 h) was mostly achieved by microorganisms. Experiments conducted with co-encapsulated NZVI-D.BAV1 achieved 100% TCE removal. During the first three hours of the experiment 100% TCE removal was achieved by NZVI, and 100% removal was achieved post re-dosing where D.BAV1 accomplished the treatment.Item A Comparative Study of Nitrification in Fargo and Moorhead Distribution Networks(North Dakota State University, 2012) Portlock, DanielNitrification in water distribution networks has become a growing concern for water supplies in the United States. The use of chloramines as a disinfectant in distribution pipe networks has become increasingly popular to reduce the disinfectant byproducts that are formed with free chlorine. In chloraminated systems there is potential for nitrification to occur because it reduces chloramine residuals. As chloramines decompose in the network, ammonia is released. Nitrifiers oxidize ammonia into nitrites, which react with chloramines resulting in its further reduction. As this cycle continues, chloramines will be consumed faster in the network, causing regrowth of heterotrophic bacteria. A study was conducted to compare the Fargo and Moorhead distribution networks for the occurrence of nitrification and their potential to deteriorate water quality. Each distribution network was analyzed independently for variations in operational conditions and water quality parameters that can serve as indications of nitrification in a distribution network.Item Comparitive Analysis of Turbidity and Organics Removal in Biological Activated Carbon and Anthracite-Sand Filters in the Moorhead Water Treatment Plant(North Dakota State University, 2019) von Hagen, EmilyThe source water for the Moorhead Water Treatment Plant (MWTP) exhibits high concentrations of total organic carbon (TOC) throughout the year and seasonal taste and odor (T&O) events. To prevent biological regrowth in the distribution system there is a need to improve organics removal in the existing biological anthracite-sand filters, especially during cold water conditions when a significant decrease in removal efficiencies are observed. Three types of granular activated carbon (GAC) were selected for a pilot study to evaluate the potential of enhanced organics and T&O removal in biological activated carbon (BAC) filters compared to anthracite-sand. Turbidity removal was also evaluated to ensure regulatory requirements could be met with BAC filters. The overall performance of the BAC filters demonstrated a significant improvement over anthracite-sand. The bituminous coal-based GACs outperformed the coconut-based GAC and exhibited surface characteristics which may have a significant impact on the removal of organics, T&O, and turbidity.Item Holistic Risk Assessment of Surface Water Contamination by Naturally Occurring Radioactive Material in Oil Produced Water from the Bakken Shale(North Dakota State University, 2016) Torres, Luisa FernandaThe risks to the environment and human health due to hydraulic fracturing (HF) in onshore unconventional oil and gas (O&G) development have been studied in the past but results are inconclusive. A common shortcoming in previous studies is the absence of social risk perception and awareness analysis. This thesis research proposes the combination of statistical methods to analyze risks to human health due to improper management of produced water, the major by-product of HF. This study focuses on the Bakken Shale located in North Dakota. A risk assessment of radium-226 was performed from a technical perspective only. A second assessment, focused on lead-210, combined technical analysis with risk perception and awareness of ND residents. Results indicate that the latter offers more holistic information that could greatly contribute to the mitigation of risks in O&G development by creation and implementation of standards and regulations that consider technical and social aspects.Item Coating of NZVI Particles With Modified Starch: Colloidal Stability and Nitrate Reduction Studies(North Dakota State University, 2015) Pate, Mary FrancisNanoscale-zero valent iron (NZVI) is an effective groundwater remediation media because it can quickly reduce and absorb contaminants. However, NZVI quickly agglomerates in aqueous systems, reducing its remediation capacity. This work investigated coating NZVI with native and modified rice, wheat, maize, and tapioca starches to improve colloidal stability. Colloidal stability studies were conducted with native and commercially available starches; tapioca starch modified with 2-Octen-l-ylsuccinic anhydride (OSA) was the best. Four concentrations of OSA-tapioca starch were prepared (3, 15, 35, and 50% w/w). NZVI coated with 35% OSA-modified tapioca starch (concentration = 10 g L-1) kept 66% of the coated particles suspended after 2 hours (compared to 4% of bare particles, p = 0.000). Bare NZVI reduced significantly more nitrate (20 mg L-1) than coated NZVI (p =0.000). Bare and coated NZVI provided the same nitrate reduction at 40 and 60 mg L-1 (p = 0.939 and p = 0.815, respectively).Item Hydrologic Experiments and Analysis: The Effect of Microtopography on Runoff Generation(North Dakota State University, 2014) Bogart, Daniel FrederickMicrotopography is an important factor in hydrologic processes. The purpose of this research was to study the effects of microtopography on runoff generation. Specifically, this was performed through an array of physical experimentation comparing “rough” and “smooth” surfaces under natural and simulated rainfall. Utilizing these types of rainfalls required experimentation to take place in both field and laboratory settings. The range of control factors in this study varied from surface microtopography to soil type, rainfall intensity/pattern, and ambient moisture content. The recorded results of the laboratory study were further compared with the output of a puddle-to-puddle (P2P) overland flow model. The physical experiments showed a trend initially favoring neither the rough nor smooth surface in runoff production. However, in subsequent experiments the rough surface appeared to substantially increase runoff production relative to the smooth surface. Additionally, good agreement was found between the results of the physical experimentation and the model.Item Development of Operational Strategies to Minimize Bromate Formation in the Moorhead Water Treatment Plant(North Dakota State University, 2014) Young, Kevin BradleyA recent study at the Moorhead water treatment plant (MWTP) determined that bromate formed during ozone disinfection and, at times, exceeded the maximum contaminant level (MCL) of 10 parts per billion (ppb) in the summer months. Operational data showed that bromate formation was directly related to raw water bromide concentration and control of the ozone system. This study was conducted with the purpose of developing and implementing operational strategies to minimize bromate formation in the MWTP. Several operational changes, including selection of source water based on bromide concentration and controlling ozone addition in a manner that reduces the ozone dose used to achieve disinfection, were implemented and were effective at minimizing bromate formation in the ozone chambers. The bromate concentration in the finished drinking water was significantly reduced and only a few samples contained greater than 10 ppb bromate.Item Influence of Molecular Interactions on Elastic Properties and Oxygen Diffusion in PolyButylene Terephthalate Polymer: A Molecular Dynamics Study(North Dakota State University, 2012) Raviprasad, MuniyamuthuIn most barrier applications, both mechanical and diffusion properties of the material are important. In this thesis the evaluation of molecular mechanisms responsible for the enhanced elastic properties of Polymer Clay Nanocomposites (PCNs) and the molecular mechanisms of Oxygen diffusion in PolyButylene Terephthalate polymer are presented. Interaction energy between PCN constituents, conformational changes of polymer, interaction energy between Oxygen molecule and polymer, rate of Oxygen and Oxygen diffusion coefficient are evaluated. Molecular simulation studies of PolyButylene Terephthalate (PBT) clay nanocomposite and Nylon6 clay nanocomposite show that a higher crystallinity polymer such as PBT would require higher attractive and repulsive interactions with organic modifier in order to make significant change in the crystallinity of PBT in the nanocomposite and in turn enhance the elastic modulus and hardness. Molecular interactions energy between Oxygen molecule and polymer, change in polymer conformation caused by thermal energy assist the Oxygen molecule to diffuse through polymer.Item Fracture Initiating Mechanism in Additively Manufactured 17-4 Stainless Steel(North Dakota State University, 2022) Anto, Anik DasAdditive manufacturing provides exceptional geometrical freedom to the designers and enables the production of parts that cannot be made through subtractive processes. Defects in additively manufactured (AM) metals are detrimental to the manufactured components. This study aims to understand the fracture initiation mechanism in as-built AM 17-4 stainless steel. Micro-computed tomography (micro-CT) analysis was conducted on the undeformed and fractured unnotched and notched specimens to characterize the defects in the as-printed specimens before and after deformation. The micro-CT analysis showed that the initial void count and volume fraction increased after the deformation indicating new void nucleation and dilation of voids. Furthermore, coalesced void colonies were noticed in the fractured specimens in the vicinity of the fracture surface. Evidence for void nucleation, dilation, and coalescence indicates ductile fracture to be the fracture initiation mechanism in AM 17-4 steel.