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Evaluation of a method for the use of periphyton recruitment on artificial substrates as an indicator of watershed land use in bays of Coeur d’Alene Lake, Idaho
No full textThe eutrophication of freshwater is a concern across the world and often occurs in areas that are in close proximity to human development. Early indicators of nutrient enrichment are generally evidenced in the littoral zones of lakes due to their proximity to incoming sources of sediment and associated nutrients. Previous studies in local lakes of northern Idaho indicated that the rapid growth of periphyton and its high biomass were directly related to human density in the sub-watersheds, making periphyton monitoring a possible tool to identify bays at risk of eutrophication. I tested the hypothesis that monitoring the growth of periphyton on artificial substrates was a tool capable to distinguish variation in watershed anthropogenic activity across bays. Seasonal nutrient loads delivered to two of the study bays were quantified to make preliminary comparisons between watersheds. The loads of total phosphorus and total residue differed between watersheds disproportionally to watershed area, indicating that some factor(s) other than watershed size, such as differences in land use, interact to cause differential nutrient loading between the bays. Despite evidence that the watersheds differed in nutrient loading indicators, periphyton response did not differ to a high degree of confidence between bays. Differential nutrient loading to bays of Coeur d’Alene Lake may be masked by different bay-specific retention regimes or other in-bay processes that lead to internal loading. These findings indicated that the approach used in this study to monitor periphyton was not a satisfactory method to detect nutrient enrichment in bays of Coeur d’Alene Lake.masters, M.S., Environmental Science -- University of Idaho - College of Graduate Studies, 2019-0
Headed for Greener Pastures: Motivations and Ideologies Underlying Palouse Farmer Participation in Sustainable Agriculture
No full textThe Palouse, a bioregion that incorporates parts of eastern Washington and northern Idaho, has arguably become synonymous with a single livelihood: farming. The substantial production of wheat and legumes through conventional methods constitutes the cultural and economic fabric of this region. Small farms are far and few between this vast, undulating prairie because the history of Palouse agriculture has not always accommodated small farms—factors like a railroad boom, government incentives, and mechanization have historically supported larger farms over homesteads. This project examines the people who choose sustainable agriculture over conventional farming. The definition of sustainable agriculture is ambiguous but often combines small-scale agriculture and organic methods with a set of varying ideologies that oppose conventional practices (like chemical use, monocropping, and tillage). Consequently, the sustainable food movement accommodates a diverse range of ideologies, with farmers from the far left and the far right able to justify their participation in sustainable practices. The Palouse farmers that contributed to this study were politically conservative, economically libertarian, religious, and pro-environment. While their belief systems were unique and not representative of all Palouse farmers, they surprisingly straddled beliefs held in both conservative and liberal circles. Through qualitative methods, I propose that four motivations constitute their ideological framework: nostalgia, masculinity, Christian fundamentalism, and libertarianism. Farmers in this study, referred to as Christian conservative sustainable farmers, navigate pro-environmental stances by justifying them through these core values. The beliefs and stances of prominent Christian conservative authors Wendell Berry and Joel Salatin are juxtaposed to Palouse farmers responses to better articulate how their unique positions are justified. The mainstream sustainable food movement has in its own way become synonymous with a few of its own descriptors: liberal, secular, and pro-environment. These farmers strayed from mainstream ideation, raising questions about why the sustainable food movement is so strongly associated with the political Left. In this thesis, I address the ideological diversity of the sustainable food movement and the greater societal impacts of an ideologically inclusive sustainable food system.masters, M.A., Anthropology -- University of Idaho - College of Graduate Studies, 2019-0
Climatic Constraints on Energy Balance, Behavior and Spatial Distribution of Grizzly Bears
No full textAlthough the influence of environmental variation on energy balance of endotherms is well understood, the degree to which climate directly constrains energy available for reproduction in large mammals has received comparatively little attention. We used a combination of biophysical and algorithmic modeling to examine the impact of temperature variation on rates of metabolism and water loss of lactating and non-lactating female grizzly bears, Ursus arctos. Our goal was to understand the conditions in which warm temperatures constrain activity (both timing and intensity) and to quantify the relative importance of regulatory behaviors for maintaining heat balance. We used the mechanistic modeling software Niche Mapper to predict energetic costs incurred by female bears in early and late summer under current (measured) climatic conditions, as well as under conditions predicted by the IPCC (i.e., 2.5o-C increase in mean temperature). When bears were allowed access to “bathtubs” (i.e., pools of cool water) to facilitate cooling they were able to maintain homeothermy under a wider range of conditions throughout the summer, especially under simulated climate warming. The relative benefit of bathtubs was greater for lactating females because of the additional endogenous heat generated by lactation. Our results suggest that behavioral mechanisms for minimizing costs of thermoregulation are likely to play an important role in the ecology of grizzly bears at the southern extent of their range under current conditions, and that increasing temperatures have the potential to constrain energy allocated to reproduction by grizzly bears. To explore this possibility further we used an algorithmic modeling approach to evaluate the relative influence of costs imposed by the thermal environment on the spatial distribution of female grizzly bears. We developed a Genetic Program to predict the relative contribution of a suite of environmental variables to the distribution of lactating and non-lactating female bears in the Greater Yellowstone Ecosystem Grizzly Bear Recovery Zone. Although our model results did not indicate that variation in the thermal environment is a more important determinant of grizzly bear distribution than other environmental factors under current climatic conditions, they did show that spatiotemporal variation in costs of thermoregulation have a greater influence on the distribution of lactating than non-lactating female bears. This result is consistent with predictions of the Heat Dissipation Limit Theory and has important implications for the distribution and performance of grizzly bear populations in the GYE as the earth’s climate continues to warm.masters, M.S., Bioinformatics & Computational Biology -- University of Idaho - College of Graduate Studies, 2019-0
Environmental Factors Influencing Phosphorus Availability and Speciation in Forest and Meadow Soils of the Lake Tahoe Basin
No full textLegacy fire suppression in the Lake Tahoe Basin has led to accumulation of forest litter, which may represent an important source of phosphorus contributing to eutrophication and reduced clarity in the Lake. The distribution and dynamics of soil phosphorus in the Basin’s forests is not fully understood. In Chapter 2, the response of three labile soil phosphorus fractions to seasonality, ecosystem, and parent material is examined between two neighboring watersheds in a site-specific analysis. In Chapter 3, relationships of different environmental, mineral soil, and organic horizon properties with several pools of soil phosphorus are described around the Basin. Results showed that 1) parent material influences the magnitude of labile soil phosphorus concentrations, 2) ecosystem type is a major driver for source of labile phosphorus, and 3) organic forms comprise the majority of soil phosphorus readily lost to surface waters. Effective mitigation of phosphorus accumulation in watershed soils should use parent material and ecosystem type to prioritize forest management strategies.masters, M.S., Plant, Soil and Entomological Sciences -- University of Idaho - College of Graduate Studies, 2019-1
INSIGHTS INTO THE PROCESSES AND LIMITING FACTORS OF BEDROCK RIVER EROSION USING FLUME EXPERIMENTS, TOPOGRAPHIC ANALYSES, AND DAMAGE CONTINUUM CONCEPTS
No full textMany important understandings of the dynamic coupling between climate tectonics and erosion are based on models of bedrock erosion. However, many questions concerning incision process and the bedrock resistance to incision remain unanswered. Mechanistic based models of erosion provide the best opportunity to model landscape evolution with the most nuanced approaches to consider the erosive energy of a stream and the properties of rock that govern the transfer of that energy into erosion. The purpose of this dissertation is to experimentally test specific mechanistic erosion equations and use fieldwork in bedrock channels of central Arizona to investigate the controls on resistance to erosion. In chapter one flume experiments of sediment transport show that adding non-planar topography to the channel floor generates heavy tail distributions of impact energies and causes the energy delivered to the bed to shift from a decreasing to an increasing relation with the shear stress of the flow. In chapter two the morphology of lithologically variant bedrock channels in central Arizona shows strong correlations with resistance factors to processes of erosion and suggests that channel slope is sensitive to the resistance to abrasion and the size of sediment in the channel while channel width is sensitive to the bedrock joint spacing and the size of sediment in the channel. Chapter three uses fieldwork to investigate the accumulation of damage in channel surfaces through sub-aerial weathering processes and sediment impacts to show that mineralogy and crystalline grain size play an important role the evolution rock erodibility in a natural setting.doctoral, Ph.D., Geology -- University of Idaho - College of Graduate Studies, 2019-1
On the Stefan Problem with Internal Heat Generation and Prescribed Heat Flux Conditions at the Boundary in Cylindrical Coordinates
No full textMy thesis focuses on the evolution of the solid-liquid interface during melting and solidication in a material with constant internal heat generation and prescribed heat ux at the boundary in a cylinder. A phase change process in which a material transitions between two phases, solid and liquid, is known as a Stefan moving boundary problem. We assume that the internal heat generation is constant and the same in both phases. The material properties in both phases are also taken to be constant and equal. We assume that the heat is transferred only by conduction and we neglect convection in the liquid phase. In addition, we assume that there is a sharp interface between two phases where the phase changes at a single melting temperature and there is no mushy zone at the interface. The presence of the internal heat generation makes the problem nonhomogeneous. Starting from the heat conduction equation, the approach nds steady-state and transient temperature solutions in each phase and employs the separation of variables technique to nd transient solutions. A nonlinear rst-order dierential equation with Fourier-Bessel series terms is derived for the time-dependent motion of the interface. Analytic solutions for temperature proles in each phase are derived. We do not introduce the Stefan number since there is only one xed temperature: melting temperature. Instead we introduce dimensionless heat ux at the boundary. The initial value problem is solved numerically, and solutions compared to the previously derived quasi-steady ones. It is shown that when the internal heat generation and the heat ux at the boundary have a close range of values, it takes longer for the front to reach steady state than when the values are farther apart. As the dierence between the internal heat generation and the ux increases, the transient solution becomes more dominant and the numerical solution of the phase change front does not reach steady-state before the outer boundary or centerline is reached. This shows that the prescribed heat ux can be used as a parameter that controls the motion of the interface. The problem has applications for a nuclear fuel rod during meltdown.masters, M.S., Mathematics -- University of Idaho - College of Graduate Studies, 2019-0
ISAAC: The Idaho Cyber-Physical System Smart Grid Cybersecurity Testbed
No full textThe landscape of cyber and other threats to Cyber Physical Systems (CPS), such as the Power Grid, is growing rapidly. Smart and distributed devices capable of extensive inter- and intra- networking are playing a more significant role in CPS thereby increasing the risks associated with such systems. Realistic and reconfigurable testbeds with correctly implemented security policies capable of mitigating threats are needed to develop, test, improve, and deploy practical cybersecurity solutions for CPS. This thesis primarily discusses the design and implementation of ISAAC, the Idaho CPS Smart Grid Cybersecurity Testbed, a cross-domain, distributed, and reconfigurable testbed, which emulates a realistic power utility and provides researchers with the tools needed to develop and test integrated cybersecurity solutions. Furthermore, the thesis showcases the post-implementation capabilities of the testbed through a two-pronged validation: i) mapping with an ICS reference architecture model; and ii) an emulated cyber-attack experimental scenario.masters, M.S., Computer Science -- University of Idaho - College of Graduate Studies, 2019-1
A Preliminary Assessment of Microstructure and Mechanical Properties of 15-5 PH Stainless Steel Processed via Direct Metal Laser Sintering
No full textAdditive manufacturing is a relatively new industrial technique for the manufacturing of desired shapes layer upon layer, which has, in recent years, begun to garner significant interest due to its potential, showing new possibilities in both part design and logistical trains. Because of the new way the materials are manufactured, new modeling techniques and a verification of material characteristics are required to ensure safe and economical design. Direct metal laser sintering (DMLS) is a powder bed, laser based additive manufacturing technique that already has industrial machines active and available. DMLS is popular because of its relatively high accuracy, ability to manufacture multiple parts simultaneously, and the low amount of waste produced during manufacture. 15-5 PH SS is a martensitic precipitation hardening stainless steel, used in aerospace, chemical, and other industries because of its high strength, excellent corrosion resistance, and good forgeablility. Even though this steel has been made via DMLS, there has been a lack of detailed examination of the additively manufactured material in comparison with its traditionally manufactured counterpart. In this study, tensile and creep tests performed on additively manufactured 15-5 PH showed an improvement of approximately 30% in elevated temperature tensile strength. This increase in tensile strength came at a reduction in ductility by 50%. Further, the creep life of the additively manufactured material was 30% greater when tested at 593 oC and 211 MPa. Examination of potential heat treatments of the additively manufactured alloy was also carried out, with the additively manufactured material exhibiting smaller precipitate sizes and higher Vickers hardness.masters, M.S., Chemical and Materials Science Engineering -- University of Idaho - College of Graduate Studies, 2019-1
Evaluating the Impact of Soil pH on Root and Crown Diseases of Wheat and Using Agricultural Limestone to Manage Soil Acidification in Northern Idaho
No full textSoil pH has been declining in northern Idaho, primarily due to the consistent use of ammonium-based nitrogen fertilizers. The major yield reducing factor in low pH soils is increased aluminum (Al) toxicity. Research is needed to determine the rates of lime needed to ameliorate the acidic soil and the economic rate of return for those rates. Studies were conducted in the greenhouse and field to explore the response of Rhizoctonia oryzae, R. solani AG-8, and Fusarium culmorum to increases in soil pH with liming. Results indicate that incidence and severity of Rhizoctonia root rot and Fusarium crown rot is likely to increase when soil pH increases with liming and that a soil pH value of 6 is optimal for these pathogens. A second component of the research was to establish long-term field studies in northern Idaho to explore the effect of three liming rates (2,242; 4,484; and 6726 kg ha-1) on ameliorating soil pH and examine the economic feasibility of these treatments. Trials were conducted at five locations for 2 years and all three lime rates significantly increased soil pH in the top 7.5 cm at all sites, with some sites experiencing increases in the 7.5 to 15 cm range. The increased pH was associated with significantly increased base saturation and reduced Al concentrations at all sites as well. Yields were increased with increasing rates of lime at many of the sites. Net present value was used to amortize the cost of liming over multiple years. Based on the data from this study, there was an economic benefit to liming in five of the seven site-years, with an average of 26 and $39 ha-1 net returns for the 2,242; 4,484 and 6,726 kg ha-1 lime rates, respectively. Preliminary data suggests that lime application in soils with documented acidification may be economically beneficial for growers in northern Idaho.masters, M.S., Plant, Soil and Entomological Sciences -- University of Idaho - College of Graduate Studies, 2019-0
Electrochemical Energy Characteristics of Bismuth Oxide with Different Polymorphs
No full textBismuth sesquioxide (Bi2O3) is a potential material to be used for supercapacitors. Bi2O3 has a theoretical capacitance of 1305 F/g. However, this value has yet to be obtained in actual experimental procedures. In this study research was done on two of the five different polymorphs that exist. These phases were the α (monoclinic) and ß (tetragonal) structures. Additionally, a third structure chrombismite (Bi16CrO27) electrochemical performance was tested. Nucleation behavior of α and ß material was determined by running galvanostatic experiments at a current density of 7.885 mA/cm2 for varying time intervals of 10 seconds, 30 seconds, 1 minute, then 5 minutes on a glassy carbon substrate. Afterward, each sample was viewed using scanning electron microscope to see how the Bi2O3 deposited on the surface. It was seen with the short time intervals that island growth or spontaneous nucleation occurred. Over longer periods of time the islands eventually grew to form platelets on the substrate. X-ray diffraction (XRD)was performed on the samples with a thicker deposit to determine if they went on in the proper crystalline phase. From reviewing the graphs, the structures showed a few broad peaks, symbolizing that it was only semi-crystalline after deposition was completed. Once nucleation behavior was determined, to obtain the true phase of each deposition they were annealed in a box furnace for 2 hours. α phase is achieved by annealing at 500° C while ß phase and chrombismite structure are done at 400° C. As deposited and annealed samples were electrochemical performance was determined using EIS, Mott Schottky, and cyclic charge discharge experiments. Each sample was compared to one another and it was determined that the as deposited chombismite material showed the most promise as a supercapacitor. Its capacitance was 361 Fg-1 at a current load of 1 mA and showed no material degradation after 20 charge discharge cycles.masters, M.Engr., Chemical and Materials Science Engineering -- University of Idaho - College of Graduate Studies, 2019-0