One of the methods being investigated for storing hydrogen is the use of metal hydride materials. Metal hydrides are able to absorb and release hydrogen, giving them a wide range of potential applications for hydrogen storage. These materials are generally considered to be safe, stable, reusable, and are able to store and release hydrogen at lower pressures and near ambient temperatures. Despite these benefits, there are still existing limitations that hinder their widespread applicability. One of the main issues presented is the necessity for effective heat removal during the absorption process. When hydrogen is being absorbed by the metal hydride material, a large amount of heat is generated, which must be efficiently removed from the metal hydride reactor in order to achieve reasonable charging times. The first section of this thesis investigates the existing methods that have been proposed and studied for heat removal during this process. Some of these methods include the use of embedded cooling tubes, external water jackets, phase change materials, and high thermal conductivity additives. A method to characterize each type of reactor is also introduced in this section, based on certain parameters, which include characteristic length, mass of metal hydride material stored, mass of hydrogen stored, and cooling time. The following section simulates cooling times for two proposed large-scale shell-and-tube metal hydride reactors. The first reactor tested has embedded cooling tubes and metal hydride powder packed into the shell side. It was found that the absorption process could be completed in 1500-2000 s, depending on the tube bundle configuration. Additionally, a large hydrogen supply pressure (30 bar) was needed for reasonable reaction times to be achieved. The other reactor packed embedded tubes with annular metal hydride pellets, with the cooling fluid passing through the shell side of the reactor. This type of reactor showed a promising cooling time of 430 s with a hydrogen supply pressure of 10 bar. This type of reactor was more limited though by the percent volume that could be occupied by metal hydride material.

Seasonal snowpack plays a critical role in hydrologic and ecologic processes. In boreal forest regions snow depth is known to be markedly different across land cover types. Identifying the vegetation metrics responsible for possible snow depth and snow water equivalent (SWE) spatial variability continues to be a challenge. Airborne lidar has advanced our understanding of links between forest snow distribution and vegetation impacts. This study analyzes high resolution (0.5 meter) lidar data sets acquired during NASA's SnowEx field campaign in Alaska and compares them statistically across the vegetation metrics of land cover class and lidar-derived canopy height. Airborne lidar data was collected for a boreal forest site, the Caribou Poker Creeks Research Watershed (CPCRW), during snow-off and peak snow-on accumulation in March of 2022 and May of 2023. Lidar snow depth (98 ± 15 cm) and canopy height maps, both at 0.5 m resolution, were created from lidar data sets. Lidar snow depth and canopy height maps were resampled to 1.5 m resolution to account for spatial autocorrelation. A total of 85.9 million lidar snow depth and canopy height values were available for this study. Three subsets totaling 6.1 million snow depths and canopy heights were processed to run the analysis. A USGS National Land Cover Database (NLCD) 2016 map of Alaska was used to determine land cover classes. Extensive in situ field snow depth measurements were collected concurrently with the peak snow-on lidar survey and were used to validate lidar accuracy. Analysis results from the three subsets showed statistically significant differences in median snow depths for all land cover classes and canopy height (p < 2.2e-16). Statistical comparison within land cover classes showed the largest significant difference in snow depths between shrub and deciduous forest (6-15 cm) and shrub and wetlands (7-14 cm). For canopy height classes, forest and treeless (12-14 cm) and forest and shrub/short stature trees (SSS) (8-14 cm) had snow depths that were significantly different. This thesis will further summarize results on quantifying snow depth variability between land cover and canopy height classes within boreal forests using NASA SnowEx Alaska data.

Biofilms in water distribution systems (WDS) can adversely affect the effluent water quality and structural integrity of pipes. Current disinfectants and flushing strategies often prove insufficient to mitigate biofilm growth. Long-term monitoring of biofilm growth under varied WDS flow and disinfection conditions is needed (and often overlooked) for improving biofilm management in the WDS. An alternative approach to counter biofilms in the WDS over the traditional approach of using antimicrobials is to target and weaken the extracellular polymeric substances (EPS) instead of just the microorganisms in the biofilms - via the use of 'detachment promoting agents' (DPAs) to weaken the EPS matrix and cause biofilm dispersion. The growth of fresh biofilm and reattachment of biofilm flocs were investigated by time-lapse imaging in capillary flow cells under varying temperatures, fluid shear, and chlorine dosage. Biofilm disruption efficacy of potential DPAs was investigated for single and multi-species biofilms over varying durations (72 h - 4 months) and on different surfaces (e.g., glass, copper, stainless steel, cement, HDPE). The similar biofilm growth rates with non-chlorinated and 0.2 mg/L chlorine indicate the ineffectiveness of low chlorine dosages for biofilm inhibition. Substantial biofilm growth occurred despite using higher chlorine dosages (0.2-1 mg/L), demonstrating the disinfection resistance of microorganisms in biofilm and detached clusters. The enhanced initial biofilm growth kinetics in the reattachment systems compared to the fresh flow cell reactors indicates the significant role of existing biofilms (and likely their detached clusters) to stimulate biofilm growth in a newer WDS section. The lower reattachment rate at the early stage with hot water (50°C) increased over time likely due to interaction with a high residual chlorine dosage. Multi-species biofilms grown for both long and short duration showed higher resistance to DPA treatment. The maximum dispersal of single-species biofilms was achieved using the DPA agent EDTA (45 ± 32%). The highest observed protein in the effluent with EDTA treatment indicates the effectiveness of DPAs for weakening EPS. Sodium tripolyphosphate (STP) reduced 75% of biomass and half of biofilm thickness on HDPE coupons. However, the formation of disinfection by-products by STP treatment (0.32-0.67 mg/L bromoform) raises regulatory concerns for DBPs. The use of DPAs as anti-EPS agents for biofilm dispersal, rather than the traditional antimicrobial approach yielded promising results for different plumbing materials. Overall, the results from this study demonstrate the potential of non-invasive imaging-based research in understanding the growth mechanisms of biofilm in various flow conditions, highlighting the widespread application of online water monitoring systems. Overall, this research offers new insights and perspectives on the impact of fluid shear and disinfectants on biofilm growth and reattachment, as well as the implications of these processes for water safety and public health.

(3-Aminopropyl)triethoxysilane (APTES) silane possesses one terminal amine group and three ethoxy groups extending from each silicon atom, acting as a crucial interface between organic and inorganic materials. In this study, after APTES was deposited on the aluminum alloy AA2024-T3 as a primer for an optional top coating with polystyrene (PS), its role with regard to stability as a protection layer and interaction with the topcoat were studied via combinatorial experimentation. The aluminum alloy samples primed with APTES under various durations of concentrated vapor deposition (20, 40, or 60 min) with an optional post heat treatment and/or PS topcoat were comparatively characterized via electrochemical impedance spectroscopy (EIS) and surface energy. The samples top-coated with PS on an APTES layer primed for 40 min with a post heat treatment revealed excellent performance regarding corrosion impedance. A primed APTES surface with higher surface energy accounted for this higher corrosion impedance. Based on the SEM images and the surface energy calculated from the measured contact angles on the APTES-primed surfaces, four mechanisms are suggested to explain that the good protection performance of the APTES/PS coating system can be attributed to the enhanced wettability of PS on the cured APTES primer with higher surface energy. The results also suggest that, in the early stages of exposure to the corrosion solution, a thinner APTES primer (deposited for 20 min) enhances protection against corrosion, which can be attributed to the hydrolytic stability and hydrolyzation/condensation of the soaked APTES and the dissolution of the naturally formed aluminum oxide pre-existing in the bare samples. An APTES primer subjected to additional heat treatment will increase the impedance of the coating system significantly. APTES, and silanes, in general, used as adherent agents or surface modifiers, have a wide range of potential applications in micro devices, as projected in the Discussion section.

An abundance of failed or abandoned public infrastructure projects contributes to Nigeria's poor quality of life and economic development. The project management process for public infrastructure projects in Nigeria is opaque to the public and has not benefited from active public stakeholder involvement. This study investigated from a public perspective, (i) factors driving the public to participate effectively, (ii) moderating effect of using e-government tools on the public's willingness to participate effectively, (iii) factors influencing the willingness of the public to adopt e-government tools and approaches to effectively participate, and (iv) current level of public participation in monitoring the execution of public infrastructure projects in Nigeria. Using questionnaire surveys and statistical analysis, the study found that the following conditions were required for active public participation to occur: (i) the public has access to and control of information on projects, (ii) the public has the power to control the agenda and influence decision making, (iii) structures are available for the public to engage with the project team and government on issues concerning public infrastructure projects, and (iv) adoption of e-government tools to public participation, as a moderating factor. It also found that, despite the low level of public infrastructure in Nigeria, the Nigerian public is ready and open to adopting e-government tools and platforms to participate in monitoring the execution of public infrastructure projects in Nigeria. This study presents new models for the participation of the public as a stakeholder group in project management. It recommends devolution of power to the public, creation of structures for public participation, enhancement of public access to information on projects, and deployment of e-government tools and approaches, such as having an interactive project website for the public to engage with the project team and government officials. This is anticipated to incentivize the Nigerian public as a stakeholder group to be more actively involved in public infrastructure project development.

Recently, there has been an increase in the occurrence of incidents involving spills of oil and natural gas, such as methane. The world experiences at least one major spill in each decade. An illustrative case is the Deepwater Horizon oil disaster in 2010 in the Gulf of Mexico. This catastrophe resulted in the discharge of about 205.8 million gallons of oil and 225,000 metric tons of methane gas into the Gulf of Mexico. More recently, in 2022, the Nord Stream pipeline leak occurred, which was the largest single methane release ever recorded. It released up to 500K tons of methane underwater, a greenhouse gas with a significantly higher potency than carbon dioxide. Due to the Deepwater Horizon incident, mammals, sea turtles, birds, fish, and invertebrates were adversely affected and caused damage to the corals. More than 90 bird species died, and 1300 miles of shoreline became polluted. The fishing industry suffered a significant reduction. This study systematically reviewed the source and impact of methane in the marine environment, utilizing 271 peer-reviewed academic publications, eight non-peer-reviewed sources, and 44 online resources. In the marine environment, methane can come from various sources such as methane hydrate, methane seeps, pockmarks, mud volcanoes, microbial activities, and anthropogenic sources or human-induced activities. Sediment typically contains methane from methane seeps, methane hydrates, mud volcanoes, and microbial activity. In the water column, methane is produced from diffusion from hydrates, seeps, hydrothermal vents, and thermogenic and anthropogenic sources. On the other hand, air-water interface methane comes from the atmospheric exchange or diffusion from the water column or sediment. In marine water, methane undergoes various reactions. Methane reacts with oxygen, producing carbon dioxide in aerobic conditions. Conversely, in anaerobic conditions, methane is anaerobically oxidized, coupling with sulfate reduction mediating by sulfate-reducing bacteria and methanotrophic archaea. These microorganisms, bacteria, and archaea derive the majority of their carbon and energy from methane, and they can proliferate their number where they find excess methane. However, excess methane can create anoxic conditions by reducing oxygen concentration. Invertebrates utilize methane through a symbiotic relationship with methane-consuming microorganisms. Moreover, the marine ecosystem exhibits complex interdependencies among the organisms and methane.

The retreat and thinning of Arctic sea ice, driven by climate change, have increased the potential for maritime navigation in the region, thereby heightening concerns about the environmental impacts of potential oil spills in the Arctic. This dissertation, with a focus on the Beaufort and Chukchi Seas, seeks to develop a remote predictive method for assessing the subsurface features of Arctic sea ice, thereby facilitating rapid responses to Arctic oil spills without depending on time-consuming in situ measurements. The first paper of this dissertation addresses the need for oil spill modelers to understand oil movement along the subsurface of sea ice. Employing sonar data from the Chukchi Sea, the study investigates whether the subsurface topography of sea ice exhibits fractal scaling behavior. It was found that young sea ice exhibits multifractal scaling geometry, with parameters α, c1, and H determined as 1.2, 0.03, and 0.12, respectively. Fractal scaling behavior was not observed in other types of sea ice, highlighting the need for further research in this area. These findings are instrumental in enhancing predictive models for oil slick migration under sea ice, a crucial aspect of Arctic oil spill preparedness and mitigation. The dissertation's second paper analyzed five years of field data to determine the statistical distributions of subsurface features beneath various ice stages, using indirect assessment techniques. The analysis revealed that, with few exceptions, the subsurface features of sea ice predominantly follow lognormal distribution patterns, each characterized by distinct mean (mu) and standard deviation (sigma) values. This research represents a significant step forward in remote sea-ice characterization and is vital for formulating effective oil spill responses in the Arctic. The final paper utilized Arctic sea ice stage data, interpreted from satellite imagery, and sea ice draft data from moored sensors in the Beaufort and Chukchi Seas. This data was pivotal in accurately modeling the under-ice morphology, essential for establishing boundary conditions for realistic gravity-driven flow simulations. The study found that potential oil sequestration volumes could range from 30,000 to 1 million cubic meters per square kilometer, varying with the ice stage conditions. Additionally, the models suggest that under-ice morphology significantly influences oil slick movement, with only 20-40% of the ice surface encountering oil. This complexity highlights the intricate nature of Arctic oil spill cleanup and the potential for oil encapsulated in sea ice to cross international boundaries, emphasizing the need for comprehensive preparedness and international cooperation in Arctic oil spill response strategies.

This project aims to restore and upgrade the UAF Clearpath platform assets, develop a web application for visualization and control, and document the process. The platforms were upgraded with the latest Clearpath Linux distributions and ROS packages, and their base stations were restored with correctly configured routers. A web application was created to provide convenient visualization and control of the UGVs through a user interface tuned for desktop and smartphone web browsers. The system allows for full control/visualization and read-only visualization through different endpoints, with driving and autonomous navigation features available through the control endpoint. The system also provides a two-dimensional map with the robot and obstacles localized on the map, and an interface for setting autonomous navigation goals. The project was thoroughly documented, and the source code and documents will remain available on GitHub for future use. The system is easily extendable and customized, allowing for the development of new navigation algorithms, user interface features, and endless other possible future projects involving Clearpath platforms.

The purpose of this project is to further advance Unmanned Aerial System flight capabilities with solar assisted flight. To reduce drag and increase flight efficiency, a flying wing configuration was selected and developed modeling the tradeoff between additional drag and power received from photovoltaic cells. To initiate the design process, strategies based on the needs were implemented to determine initial constraints. As the design methodology progressed, the selected parameters were finetuned and optimized to best meet the performance requirements and simplify the fabrication process. The chosen design was modeled for computational fluid dynamics simulations, stability and control analysis, and finite element analysis before manufacturing and physical testing. With the iterative design methodology, a final design was determined, and a prototype was developed testing the foam manufacturing processes and the overall design compatibility. Preliminary testing of the aircraft without photovoltaic cells as well as tests of the cells with the power system were performed to validate the power requirements and confirm the performance predictions.

In a study published by the US National Renewable Energy Laboratory (NREL), it was shown that “Renewable energy sources, accessed with commercially available technologies, could adequately supply 80% of total U.S. electricity generation in 2050”. Therefore, a very rapid increase in renewable energy penetration in electric power systems is expected. The renewable energy harvesting process (except solar energy) involves technologies that utilize electric generators for energy conversion. Thus, the performance of generation units used in the renewable energy harvesting process is becoming more critical in electric power system stability, energy efficiency, and power cost. This project presents a characterization process performed on a novel dual stator permanent-magnet generator by using finite element analysis (FEM). The novel design is patented by the U.S. Patent and Trademark Office. The machine is built by using a state-of-the-art industryscale electromagnetic simulation tool available at the Department of Electrical and Computer Engineering at the University of Alaska Fairbanks. The patented design incorporates two types of generators; single-phase and three-phase types. This project is based on a three-phase design. The machine’s electrical and mechanical specifications which are detailed in the patent document were implemented, except the exciter design. It was decided to replace the proposed electromagnetic coils with permanent magnets. This selection was made to eliminate the copper loss in the field circuit (rotor) to maximize the machine’s efficiency. This also eliminated the use of slip rings and brushes which are considered a disadvantage due to the frequent maintenance requirement. However, it has the advantage of providing better control on the generated power at a wide range of speeds. NdFeB magnet is selected as it provides better flux density in low-speed operation. This was concluded via a comparison process conducted on magnet types available in the simulation tool. Based on the patented design, the generator was simulated with 12 rotor poles and 24 stator teeth. A reference speed of 600 rpm is used to ensure 60 Hz frequency operation. Due to the amount and type of steel used to build the apparatus, the machine demonstrates a quality reduction in the steel saturation under full-load operation especially at the critical parts of the machine (armature teeth). More importantly, the machine shows a high level of full-load efficiency. It is important to mention that this project is not a complete research work. Further characterization and optimization processes are still to be performed for the novel design to manifest its highest performance. This may be a research work to pursue in the future. This project was one step in this direction.