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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 Fate and Characteristics of Dissolved Organic Nitrogen through Wastewater Treatment Systems(North Dakota State University, 2012) Simsek, HalisDissolved organic nitrogen (DON) represents a significant portion (25-80%) of total dissolved nitrogen in the final effluent of wastewater treatment plants (WWTPs). DON in treated wastewater, once degraded, causes oxygen depletion and/or eutrophication in receiving waters and should be reduced prior to discharge. Biodegradability, bioavailability, and photodegradability are important characteristics of wastewater derived DON and are subjects of research in this dissertation. Four research tasks were performed. In the first task, laboratory-scale chemostat experiments were conducted to examine whether solids retention time (SRT) could be used to control DON and biodegradable DON (BDON) in treated wastewater. Nine different SRTs from 0.3 to 13 were studied. There was no correlation between effluent DON and SRTs. However, BDONs at SRTs of 0.3 to 4 days were comparable and had a decreasing trend with SRTs after that. These results indicate the benefit of high SRTs in term of producing effluent with less BDON. The second task was a comprehensive year-round data collection to study the fate of DON and BDON through the treatment train of a trickling filter (TF) WWTP. The plant removed substantial amounts of DON (62%) and BDON (76%) mainly through the biological process. However, the discharged concentrations in the effluent were still high enough to be critical for a stringent total nitrogen discharge limit (below 5 mg-N/L). Evolution of bioavailable DON (ABDON) along the treatment trains of activated sludge (AS) and TF WWTPs and relationship between ABDON and BDON were examined in the third task. ABDON exerted from a combination of bacteria and algae inocula was higher than algae inoculated ABDON and bacteria inoculated BDON suggesting the use of algae as a treatment organism along with bacteria to minimize effluent DON. The TF and AS WWTPs removed 88% and 64% of ABDON, respectively. In the last task, photodegradable DON (PDON) in primary wastewater and final effluent from TF and AS WWTPs was studied. PDON and BDON fractions of DON data in the final effluent of TF and AS WWTP samples elucidate that photodegradation is as critically important as biodegradation when mineralization of effluent DON is a concern in receiving waters.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 Building Envelope Containing Phase Change Materials for Energy-Efficient Buildings(North Dakota State University, 2021) Li, MingliEnergy consumption in the building sector has increased dramatically over the past two decades. The incorporation of phase change materials (PCMs) into building envelopes is considered as effective thermal energy storage to improve building thermal performance and reduce space heating/cooling load. Despite significant efforts in PCMs technologies and their application to buildings, how to select proper PCMs for buildings and maximize the activation of their latent heat to effectively improve building energy efficiency still post great challenges. The lack of systematic and comprehensive studies in these gaps hinders their broad applications in the building sector. This study aims to develop a holistic framework through experimental and numerical studies to gain a deep understanding of the thermal property of PCM and the heat transfer mechanism of the exterior wall integrated with PCM. A novel shape-stabilized paraffin/expanded graphite(EG) composite is prepared and its thermal behavior is investigated through thermal energy storage and heat transfer test. The impact of critical design parameters including the location, thickness, latent heat, melting point, and thermal conductivity of PCM on the thermal performance of a multilayer wall is explored using COMSOL Multiphysics® software. The thermal storage and heat transfer test show that EG can significantly enhance the heat transfer rate of paraffin. In addition, the paraffin/EG composite possesses favorable thermal energy storage ability to decrease the indoor temperature fluctuation and shift the peak load. Among the aforementioned design parameters, melting point of PCM is critical to significantly influence the building thermal performance. To effectively account for melting point of PCM and enhance the service efficiency of PCM, a new wall configuration containing PCM with hybrid melting points is proposed. The proposed wall assembly is found to benefit the indoor thermal comfort and the activation of the latent heat of PCM when the ambient temperature covers cold, mild, and hot loading conditions for the long term. Moreover, coupling vacuum insulation panels (VIP) with extremely low thermal conductivity and PCMs with a large amount of latent heat in the building envelope is another solution to further enhance building thermal performance due to the increased thermal insulation and thermal inertia.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 Development of Improved Methods for Watershed-Scale Topographic Analysis and Hydrologic Modeling(North Dakota State University, 2020) Wang, NingSurface depressions are one of the significant topographic characteristics in depression-dominated areas and can retain runoff and break the hydrologic continuity in watersheds. In traditional semi-distributed models, the entire area of a watershed is assumed to be well connected to its associated outlet and depressions are often lumped as a single depth to control runoff water release. Consequently, hydrologic processes related to depressions cannot be directly simulated. The overall goal of this dissertation research is to analyze and quantify the topographic characteristics of surface depressions and their impacts on hydrologic processes in depression-dominated areas. The specific objectives of this research are: (1) to improve watershed delineation to further reveal the topographic characteristics and hydrologic connectivity within watersheds, (2) to analyze the impact of depressions on runoff processes during rainfall events and the mechanism of water release from depressions, and (3) to analyze the functionalities of depressions in continuous simulation of hydrologic processes and connectivity. A new algorithm was developed for hydrologic unit delineation of depressions and channels (HUD-DC), in which a unique method was proposed to identify depression- and channel-associated hydrologic units and their connections. The HUD-DC delineation results highlighted the significance of depressions and the complex connectivity in depression-dominated areas. Additionally, the delineation under different filling conditions provided helpful guidance for the identification of filling thresholds to remove artifacts in digital elevation models. To achieve the second objective, a depression-oriented, event-based hydrologic model (HYDROL-D) was developed with considering separate modeling for depressional and non-depressional areas, and hierarchical control thresholds for water release from depressions. The HYDROL-D modeling results for a watershed in North Dakota revealed the intrinsic threshold behavior of surface runoff over the watershed and the effectiveness of the hierarchical control thresholds. A depression-oriented hydrologic model with accounting for dynamic hydrologic connectivity (HYDROL-DC) was further developed to continuously track runoff unit by unit. The application of HYDROL-DC in a depression-dominated watershed showed that depressions had not only retention but also acceleration capabilities in surface runoff generation. Additionally, the spatial distribution of depressions exhibited dynamic influences on hydrologic connectivity and the related threshold behavior of runoff processes.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.