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Application of Nanocrystalline-Graphite (GUITAR) in Electrochemical Energy Storage and Sensing
No full textNanocrystalline-graphite produced from pyrolyzed vegetable oil has properties that deviate from typical graphites, but is similar to the previously reported Graphite/Graphene from the University of Idaho Thermolyzed Asphalt Reaction (GUITAR). GUITAR has the classical basal and edge plane morphology similar to graphite and graphene with similar X-ray photoelectron spectroscopy (XPS), Raman and IR characteristics. However, GUITAR is electrochemically different from both graphite and graphene. GUITAR has (i) faster heterogeneous electron transfer rate across its basal plane, (ii) an electrochemical window that exceeds graphitic materials by 1 V and (iii) higher corrosion resistance beyond graphitic materials. To discover the structural basis for these properties, characterization of GUITAR was investigated with Raman and X-ray photoelectron spectroscopies, density, X-ray diffraction (XRD), thermogravimetric and elemental analyses (see Chapter-1). These characteristics established GUITAR as a new form of carbon different from previous forms. The aforementioned beneficial electrochemical properties of GUITAR are examined for application in different fields like as electrochemical energy storage (vanadium redox flow battery – VRFB, chapter-2) and electrochemical sensing of important electroactive analytes (chemical oxygen demand – COD and free chlorine – HOCl and ClO-, see chapter 3 and 4, respectively). The results explained in this dissertation show that GUITAR is an excellent alternative material for the negative electrode in the vanadium redox flow battery and an effective sensor material for determination of chemical oxygen demand and free chlorine.doctoral, Ph.D., Chemistry -- University of Idaho - College of Graduate Studies, 2019-0
Thermal behavior of cold plated storage cask for used Light Water Reactor nuclear fuels
No full textApproximately every 18 months, the fuel in a nuclear reactor is replaced, given that most of the fissionable material is depleted. The removed spent fuel is placed in pools of water inside the power plant for 10 to 20 years, for the purpose of allowing radioactive decay to occur and the heat load to lessen, after which they are transferred into dry cask storage. Although dry cask storage is a robust technology, only a small fraction of the used fuel is stored in them. This research is based on a proprietary pipe–casting technology for a cold plate cast by Sakae Casting. Sakae’s Cold Plate has the design advantages of eliminating gaps between the aluminum plate and pipes, affordability, ease of use, and overall fabrication cost. The vision for this technology is to enhance the safety of used fuel management by reducing and preventing further accidents with this sophisticated cooling device, while potentially lowering maintenance costs and optimizing the dwindling storage space. With the right cask materials, the cask can potentially provide sufficient shielding, and maintain subcritical safety. This research explores the thermal behavior of this innovative cask for cooling used fuel without the need for large pools. It involves the experimental and numerical study of a 1/3 scaled model of a used 17 x 17 light water reactor fuel assembly and the subsequent numerical analysis for an actual size assembly.masters, M.S., Nuclear Engineering -- University of Idaho - College of Graduate Studies, 2019-1
Low-Income Household Livelihood Strategies: Food Stamp Access and Private Aid Usage
No full textDoes access to food stamps influence how low-income households use financial help from family and friends? Changes to the Supplemental Nutrition Assistance Program (SNAP) could affect not only low-income households but the informal financial networks of those households, leading to larger effects than anticipated. Using the Panel Study of Income Dynamics from 1999-2007, I exploit a change in SNAP categorical eligibility in 2000 in order to create a difference-in-difference model. I find that SNAP usage increases significantly due to this change in eligibility but that private aid usage does not. Two explanations seem likely: (1) the relationship between the two types of aid is weak, especially as income increases, (2) some households lack robust private aid networks. Low-income SNAP households that seem to have less private aid available to them are generally married, less educated, urban, and/or Black.masters, M.S., Agricultural Economics and Rural Sociology (Applied Economics) -- University of Idaho - College of Graduate Studies, 2019-0
SAMPLING METHODS FOR LEK AND BROOD COUNTS OF GREATER SAGE GROUSE: ACCOUNTING FOR IMPERFECT DETECTION
No full textA central component of wildlife conservation and harvest management is accurately estimating population abundance and parameters that influence breeding productivity. Inferences about wildlife population abundance are only accurate if study designs adequately reflect temporal and spatial changes in vital rates. Greater sage-grouse (Centrocercus urophasianus; hereafter, sage-grouse) are a species of conservation concern due to continued population decline since the 1940’s and ongoing threats to their habitat. Currently, investigators use counts of male greater sage-grouse at leks and brood counts of radio-marked hens to indicate annual change in sage-grouse abundance and breeding productivity. Lek and brood counts are essential to inform harvest management, Endangered Species Act listing decisions, and land management policies. However, inferences based on these uncorrected counts may be biased if investigators fail to account for spatial and temporal variation in detection probability. In chapter 1, we used generalized linear mixed models to estimate the probability of visually and aurally detecting active leks during mock point-count surveys along lek routes. We also examined whether 15 factors influenced aural lek detection and we used a Huggins model to compare aural lek detection probabilities between audio-recording equipment and surveyors. Our results demonstrated that surveyors can aurally detect active leks at greater distances (300% further) compared to visual-only surveys. Our results suggest aural detection probabilities of an active lek were highest near 8 April, within 30 mins of sunrise, on relatively calm and cold days, when surveyors were at higher elevations relative to the lek, in areas of low topographic roughness, during times with no background noise, and on mornings following moonless nights. Audio-equipment had higher lek detection rates compared to real-time surveyors. Our results suggest that 1-min point-count surveys on lek routes would greatly increase detection rates (and reduce bias). To implement 1-min point-count surveys along lek routes, some of the existing lek routes may need to be shortened or split to ensure that the lek routes can be completed during the optimal times when grouse attend leks. By incorporating 1-min point-count surveys at regular intervals along lek routes, surveyors will be more likely to locate all leks along a survey route (including leks that move from one year to another). Therefore, analysts will be able to use the data to produce more accurate estimates of population trends for male sage-grouse. In chapter 2, we used Cormack-Jolly-Seber (CJS) and Huggins models to estimate survival and detection probabilities of radio-marked hens with broods. Furthermore, we reviewed the sage-grouse literature to summarize brood survey methods used in past studies, including variance, bias, and detection probability associated with each method. We used CJS models to compare brood survival and detection probabilities with data generated from daytime surveys (flush and visual) and nighttime spotlight surveys against a novel brood fecal survey method whereby brood status is assessed indirectly via the presence of brood feces at nighttime roost-sites. A Huggins model was used to estimate differences in detection probabilities among daytime flush surveys, fecal surveys, and nighttime spotlight surveys for broods at 42 days after hatch. We demonstrated that detection probability of daytime surveys (visual and flush surveys) changes with brood age, whereas brood fecal surveys had comparably high detection rates that did not vary with brood age. Our novel brood survey method was as effective as daytime surveys but had a lower probability of flushing hens and their broods (a drawback of daytime brood surveys). Based on our literature review, we need more standardization and rigor in sage-grouse brood survey methods and design. For example, we found only 2 studies that accounted for imperfect detection when using daytime brood surveys to estimate brood or chick survival. We also found wide disparity among studies regarding the metrics they used to determine brood fate, statistical analyses used, and the frequency and duration of monitoring periods used to estimate habitat selection, hen productivity metrics, and estimate brood or chick survival. Greater sage-grouse are of substantial management concern. Unbiased estimates of sage-grouse population trends, abundance, and breeding productivity metrics are important to prevent inaccurate conclusions and inappropriate management actions. Our results provide managers and future researchers with some potential ways to improve future monitoring efforts and management decisions.masters, M.S., Natural Resources -- University of Idaho - College of Graduate Studies, 2019-0
Nature Engagement for Health: Enhanced Methods to Improve Connection and Reduce Stress
No full textGuided by literature on wellbeing benefits of nature interactions, this dissertation presents a quasi-experimental study examining the effects of four barrier-lifting lessons to prepare participants for a nature engagement intervention versus control in natural versus urban environments. Previous research has not addressed the way people engage with natural environments for optimizing health and wellness. Measures of perceived stress, connectedness to nature, and mindfulness in nature were collected at three time points to examine the effect of type of engagement with nature and` natural versus urban environments. Results from repeated measures analysis of variance indicate all groups increased connection to nature (F(1, 86) = 74.22, p doctoral, Ph.D., Movement & Leisure Sciences -- University of Idaho - College of Graduate Studies, 2019-1