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Evaluation of the Thermal, Mechanical and Rheological Properties of Recycled Polyolefins Rice Hull Composites
No full textAbstract The elevated amount of polyolefin production, low recycling rate and increased landfill has created an environmental concern, and more innovative studies are still ongoing to reuse and reduce this waste efficiently. One out of many remedies, is the manufacture of composites with a polyolefin matrix and a reinforcing filler. The use of natural fibers as fillers for polyolefins has evidently proven to improve physical, mechanical, thermal and flow properties. Different factors affect the final product properties of a composite from fiber particle size, interfacial bonding between matrix, processing temperature amongst many. Hence, this research was done to investigate the influence of rice hulls of different sizes (<0.5 mm and <1 mm) used as reinforcement for common polyolefins of recycled high-density polyethylene (rHDPE) and polypropylene (rPP) rice hulls composites. Mechanical characterization of the composites was done using dynamic mechanical analysis (DMA) and tensile testing. Thermal characterization was achieved via differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and thermomechanical analysis (TMA). Flow properties were determined using melt flow rate (MFR), dynamic and capillary rheological methods. Surface chemistry analysis was performed using Fourier Transform Infrared (FTIR) Spectroscopy. Results showed an increase in tensile and viscoelastic properties for the <0.5 mm rice hull composites for both polyolefins. These results were compared to those of virgin polyolefin rice hull composites and wood plastic composites (WPC). It was evident that recycled polyolefin rice hulls composites can be used as replacements for wood and virgin polyolefin composites since they exhibited similar properties.masters, M.S., Chemical and Materials Science Engineering -- University of Idaho - College of Graduate Studies, 2020-0
Overpopulation in Late Twentieth-Century American Imagination
No full textOverpopulation caught the attention of scientists, popular science authors, and science fiction creators alike in the second half of the twentieth century. Overpopulation embodied the disaster that would finally bring about the end of the world as they knew it. Concerns varied between the groups, but generally focused on standards of living, quality of life, gender roles, reproduction, freedom, or access to a healthy natural world. Science writers and science fiction creators worried that society did not effectively understand the devastating potential of overpopulation and played upon Americans’ fear of loss to try to induce a greater response to the threat of overpopulation. A Gallop poll in 1971 showed that 46 percent of respondents said U.S. population growth was a major problem. Though, not everyone agreed that overpopulation posed a threat. Those who believed in the overpopulation menace could not agree on how to address it. There was no unified path forward. Americans, clear from newspaper articles discussing the country’s policies, did not want to implement the same population control tactics as communist China, but neither did most Americans want to share or give up any resources. Any measure to end the threat of overpopulation seemed too extreme and failure seemed unavoidable with either controlling reproduction or not acting. The scale of the problem of overpopulation also felt daunting. The American public felt largely separated from most of the negative effects of overpopulation. Many within the U.S. public eventually saw overpopulation as a sort of trope.masters, M.A., History -- University of Idaho - College of Graduate Studies, 2020-0
Estimating Parameters of the SIR Epidemiology Model using Simulated Survey Data and Multinomial Maximum Likelihood
No full textBrian Dennis and William Kemp (et al.) in ”Stochastic Model of Insect Phenology Estimation and Testing” use a Multinomial Maximum likelihood approach to estimate model parameters via ratios between variables. The model in this paper attempts to estimate deterministic epidemiological population parameters for the Kermack-McKendrick SIR model using simulated sample survey data. Ratios between populations in the SIR model are used as probabilities in the Multinomial distribution and resulting estimates of population paarameters are analyzed via Bootstrap confidence intervals, visual analysis, and mean squared error (MSE) estimates. The results show that certain surveys schemes perform better than others based on survey sample size, number of surveys, and survey spacing. All simulations generally produce unbiased estimates with some producing smaller variances than others. Applications include the estimating of infectious disease dynamics using small survey sampling in rural or small town universities and populations.masters, M.S., Statistical Sciences -- University of Idaho - College of Graduate Studies, 2020-0
Electrolytic Reduction of Metal Oxides in Molten Li2O/LiCl
No full textThe electrolytic reduction of metal oxides is a promising approach for producing high purity metals. However, the commercialization of the process is challenged by low current efficiency. The low current efficiency is due to the slow oxygen ion diffusion through the oxide particles. In order to improve the current efficiency, it is important to understand the reduction mechanism and find solutions to the key factors. This project focuses on fundamental electrolytic studies and the sonication operating mechanisms in molten salts. Metal oxides (NiO, and TiO2) were reduced in a small scale through electrolytic approaches in molten Li2O/LiCl at 650 °C. The reductions were carried out by controlling the total applied charges, and the cathodic potential at overpotentials and underpotentials. To accurately control the cathodic potential, a three-terminal electrolytic cell was used, including an oxide basket cathode, a glassy carbon crucible anode and a Ni/NiO reference electrode (RE). The reduced products are characterized for compositions and oxygen levels using X-ray diffraction (XRD) and Thermogravimetric Analysis (TGA). The XRD results were analyzed with the Rietveld refinement to get the concentration of the components. Salts after reductions were analyzed for metal element contents using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The reduction extent, current efficiency were calculated as the key parameters in evaluating the process. Ni/NiO reference electrode was used in the reduction, due to its stable performance in electrolyte with varying O2- concentrations, compared with glassy carbon (GC), tungsten (W), and molybdenum (Mo) reference electrode. The correlation of the electrode potentials among the GC, W, Mo and Ni/NiO RE was defined in both molten LiCl and 1 w.t.% Li2O/LiCl. The lithium deposition potential measured with Ni/NiO reference electrode was -1.75 V ~ -1.95 V vs. Ni/NiO, based on the fabrication method of the Ni/NiO reference electrode. In the overpotential reductions of NiO, Ni metal was produced at a high current efficiency of 96.1%. The reduction followed a one-step reduction mechanism and a fast kinetics. The NiO was reduced directly by the lithium metal and electrons without any intermediate involved. Samples were analyzed with XRD and TGA. The success in the NiO reduction verified the feasibility of the experiment setup and the methodology. The reduction of TiO2 at overpotentials generated lithium titantes Li2TiO3 and LiTiO2. The reduction followed multiple steps and generate multiple interfaces. Li2TiO3 was formed on the outer shell of the particle through a spontaneous chemical combination reaction of TiO2 and Li2O. When the lithium metal was generated on the cathode, it reduced the TiO2 core to LiTiO2. Finally, the Li2TiO3 shell was reduced with Li metal to LiTiO2. LiTiO2 was the final product of the reduction at -0.3 V vs. Li/Li+ with 150% of theoretical charge, resulting in a 25% of reduction extent and 16.7% reduction extent. The oxygen ion diffusion through the solid phase was found to be the rate-limiting factor in the reduction. The sonication was coupled with the TiO2 electroreduction process in both overpotential and underpotential controls. By using the ultrasound agitation, the current efficiency was improved. For overpotential reductions, the current efficiency was increased from 26.7% to 27.4%; and for the underpotential reductions, the increment was higher, from 36.7% to 44.5%. So, the introduction of sonication in the reductions can enhance the internal oxygen ion diffusion inside the metal oxides, and as the result, improve the current efficiency. The results and conclusion in this work could promote the commercialization of the metal production through electrolytic reductions and ultrasound technique in molten salts, and impact the pyroprocessing technology for the treatment of spent nuclear fuels.doctoral, Ph.D., Chemical and Materials Science Engineering -- University of Idaho - College of Graduate Studies, 2020-0
Professional Development Opportunities and Needs of Secondary Family and Consumer Science Teachers in the Northwest United States
No full textWith U.S. school districts spending an average of $18,000 per teacher per year on professional development and teachers themselves spending approximately nineteen full school days participating in it per year, a significant gain in teacher effectiveness or development of student skills has not been seen (The New Teacher Project, 2015). This could be attributed to the 60% of teachers who responded that they did not think that the professional development they received was effective or a good use of their time (The New Teacher Project, 2015). This is alarming as a crucial element of teaching secondary FCS is maintaining relevant curriculum and course content. Without effective professional development, secondary FCS teachers do not have the appropriate information to teach their students and successfully prepare them to enter a competitive and rapidly evolving workplace environment. To work toward resolving this issue, needs assessments must be conducted to find the areas where teachers need professional development assistance. This study was a quantitative descriptive study which utilized a survey instrument based on the Borich Needs Assessment Model, containing multiple choice, Likert scale, and text entry questions. It collected data to determine the perceived importance and competence of secondary FCS teachers, in Idaho, Montana, Oregon, Washington, and Wyoming, in relevant education components, including technology; course, curriculum, and standards development; teaching; and professional development, programs, and organizations. It collected data on their perceived needs for relevant and applicable professional development and access to other programs/organizations. It also collected data on motivators, deterrents, and preferred methods for participating in professional development. Using this data, the study compared the differences in perceived needs for professional development of secondary FCS teachers based on their professional and personal demographics. Lastly, it collected data on their personal opinions of how frequently state and national FCS standards should be updated.masters, M.S., Family and Consumer Sciences -- University of Idaho - College of Graduate Studies, 2020-0
Molecular Evaluations of Interaction Between Host and Mucosal Microbiota in Culture Salmonids
No full textThe biggest hurdles to the environmentally and economically sustainable aquaculture production of finfish involve issues related to disease and nutrition. Mucosal tissues and their associated commensal microbiota lie at the interface between animal and environment and are known to play an integral role in both nutrition and immunity, yet their interactions have been poorly studied in fish. As such, the aim of the work presented here was to utilize high- throughput molecular methods to provide a comprehensive and resolute characterization of salmonid mucosal tissues and their bacterial microbiota in response to multiple sources of variation, which are commonly encountered in an aquaculture setting (i.e. host genetics, mucosal tissue, developmental stage, diet, viral and bacterial disease, and stage of infection). In the first study, it was shown that Atlantic salmon differentially regulated their gut, gill, and skin microbiota, irrelevant of dietary functional feed treatments, and differences in key host regulatory immune genes across tissue showed high correlation with bacterial microbiota communities (Procrustes, correlation = 0.818, p ≤ 0.001). The functional capacity of microbiota showed adaptive differences in bacterial metabolism by tissues with increased fermentation and nutrient metabolism pathways detected in the gut and denitrification pathways being more abundant in microbiota of the gill, the primary site of excretion of endogenous ammonia in fish. Bacterial gene ontology was correlated with bacterial phylogenetic composition, but pathway level comparisons showed many bacterial pathways to be highly conserved across phylogeny. A second study was conducted to compare intestinal transcription and gut microbiota at critical early life stages (40 and 65 days post hatch) in a commercial strain of rainbow trout and a strain selectively bred for growth performance on a sustainable all plant-protein diet. Selected trout showed superior growth at early life stages and hundreds of genes and gut bacteria were identified as biomarkers of the select strain. As the first study to conduct high-throughput differential transcript usage (DTU) analysis on RNA sequencing data in an aquaculture species, results also highlighted some 74 intestinal genes that were expressed by different mRNA isoforms, depending on trout genetics and developmental stage. As in the first research chapter, the dynamics of gut microbiota communities across trout strains and ontogeny showed high congruency to that of transcriptome-wide intestinal gene expression profiles (Procrustes m2 = 0.19, correlation =0.9, p ≤ 0.001). In the final study, naïve individuals from these same strains of rainbow trout were challenged with virulent infectious hematopoietic necrosis virus (IHNV) or Flavobacterium psychrophilum, (Fp) viral and bacterial pathogens that cause severe epizootics in salmonids, often with high mortality rates. Samples were collected at early (4-5 days post challenge [dpc]) and late (20-21 dpc) timepoints to track the dynamics of serum immune response, intestinal transcription, and gut microbial ecology. The select stain showed superior resistance to the bacterial challenge compared to the commercial strain (70.4% vs 94.8% mortality), but not the viral challenge (51% vs. 52%). Serum lysozyme and alternative complement activity were generally higher in the select strain. Intestinal transcription data indicated that DTU is an advantageous molecular mechanism utilized by rainbow trout to cope with both viral and bacterial infections, as many of the isoforms involved in DTU were related to crucial functions involved in effective disease response. Gene expression data showed rather classical responses to infection, with some clear differences between trout genetics as well. The IHNV challenge led to an influx of opportunistic bacteria not traditionally observed in the fish gut, though the community was slightly stabilized by the late recovery stage of disease. In the Fp challenges, the pathogen was found to take over the gut bacterial communities and showed dominant abundance in the gut during early infections, despite not being thought of as a target tissue of the bacterium. However, by the late recovery stage, beneficial commensal bacteria began recolonizing the gut of challenged select strain survivors, as the communities began to more closely resemble uninfected controls. Together, these studies provide many novel data on host and microbiota responses in cultured salmonids. The insights presented here have valuable implications on continued efforts to improve mucosal vaccines, selective breeding of finfish, fish health management, pre- and probiotic development, as well as our basic understanding of host-microbiota- environment interactions, in general.doctoral, Ph.D., Natural Resources -- University of Idaho - College of Graduate Studies, 2020-1
Unicon's OpenGL 2D and Integrated 2D/3D Graphics Implementation
No full textWriting an OpenGL implementation for Unicon’s 2D facilities introduces an opportunity to create an integrated 2D/3D graphics mode that is intuitive to the end user. The implementation must be backwards-compatible with existing Unicon 2D graphics programs. The completion of the project will result in the release of the OpenGL implementation in public beta. Evaluation of this implementation shows it be qualitatively and quantitatively robust.masters, M.S., Computer Science -- University of Idaho - College of Graduate Studies, 2020-0
Corrosion Behavior of Calcium Containing 5xxx/6xxx Aluminum Alloys
No full textAluminum alloys containing magnesium and silicon as main alloying elements are used for automotive applications. During the casting process, calcium can be a trace element or is introduced through deliberate addition. The addition of calcium may influence the corrosion properties of the alloy and introduce microstructural and compositional changes. This study investigates the potential effects of added calcium in corrosion behavior of as-cast, heat treated and rolled 5xxx and 6xxx Al alloys using standard corrosion evaluation techniques, like Tafel and cyclic polarization. Trace amount of calcium showed minimal effect on the corrosion behavior of the Al alloys, however it introduced modifications to the microstructure of 6xxx Al alloys. The as-cast 5xxx alloys showed improved passivity compared to the homogenized samples. During the heat treatment procedure, the size and distribution of intermetallic particle can disrupt the protective oxide layer lowering the corrosion resistance in homogenized alloys. Both 5xxx and 6xxx Al alloys showed susceptibility towards pitting corrosion. The as-cast 6xxx Al alloys showed increased susceptibility towards localized pitting corrosion with pits initiating at the center of the cell. This has been attributed to the inhomogeneous distribution of solute elements such as Si and Mg within the grain and their electrochemical difference with the Al-matrix. The effect of sensitization on corrosion behavior of 5xxx Al alloys was also studied. The 5xxx Al alloy showed slight improvement in corrosion behavior with increasing sensitization time up to 100 hrs. The corrosion behavior of the rolled Al alloys did not show significant differences compared to the cast Al alloys.masters, M.S., Materials Science -- University of Idaho - College of Graduate Studies, 2020-1
Real-Time Traffic Monitoring using Airborne LIDAR
No full textThe expansion of deployed traffic monitoring systems and information transmission is a crucial step towards increasing the efficiency, reliability and safety of vehicular transportation. Under the current context in terrestrial transportation, the implementation of real-time traffic analysis mechanisms can provide more insight into the network, leading to better informed decisions on how to direct traffic and plan roadways. In the future, as we move towards the integration of fully autonomous vehicles to a transportation network with human drivers, the extraction and processing of real time data will become even more crucial to ensure safe transition. In this paper we present a real time data analysis system for in-flight vehicle detection as an option for the expansion of traffic monitoring. The presented solution is able to perform typical post-flight processing in real time, with minimal computational and power requirements, which allows its implementation on light-weight UAS. It utilizes adaptive segmentation and 3D convolutions that take advantage of the structure of the LiDAR point cloud, to identify vehicles and their respective positions within 3D point cloud segments that may include background clutter. All the necessary positioning information required to run the algorithm are introduced along with a detailed description for the computational steps extracting the desired features from the raw data. We provide the timing constraints for the system and evaluate its performance while considering different optimization variables and computation capabilities.masters, M.S., Electrical and Computer Engineering -- University of Idaho - College of Graduate Studies, 2020-0
The Mormon Utopia Kitchen: Foodways and Diaspora in the 19th Century Nauvoo, Illinois Community
No full textNauvoo, Illinois is a small town, known today as a summer tourist destination because of rich religious history of the Church of Jesus Christ of Latter-day Saints (LDS or Mormons) and other branches of the Mormon restoration movement such as the Community of Christ church. The last several seasons (2015-2019) were spent excavating the property of Samuel Harrison Smith, brother to Joseph Smith who was the first LDS prophet of the church. The excavations revealed a small foundation to a Mormon period structure along with about 35,000 artifacts, suggesting it must have been a sort of community structure if not a community waste disposal area. This thesis presents the faunal remains and the ceramics will help to understand the foodways of Mormon people as a community and others living on the frontier during the Mormon occupation of Nauvoo. Results of the artifact analysis have revealed patterns of diasporic behavior of a religious group holding on to a life they knew while also adapting to changes their movements bring.masters, M.A., Anthropology -- University of Idaho - College of Graduate Studies, 2020-1