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Predicting Properties of Bio-jet Fuels using Machine Learning and ATR-FTIR Spectroscopy
Get PDFHigh-potential molecules derived from biomass sources may suitably replace or supplement traditional nonrenewable hydrocarbon fuels to reduce pollution and fuel processing costs. Due to expensive and time-consuming property testing, models that predict key properties from optical data would initially vet potential additives before investment and bench-scale testing. Attenuated Total Reflection (ATR) FTIR spectroscopy can provide a fast and inexpensive fingerprint of a liquid fuel to predict properties. I trained and compared three supervised machine learning regression models to predict five fuel properties: H/C ratio, molecular weight, flash point, freezing point, and cetane number. I propose a new feature engineering method that uses features from a Lasso-regularized model as reduced input features to other algorithms. The remaining features were further reduced by removing highly correlated variables to reduce overfitting. I included the bio-jet fuel blends of F-24 with p-menthane, pinane, farnesane, and RJ-4 at additive relevant concentrations. The properties in the holdout set were predicted with R2 correlations between 0.93 and 0.95
An Exploration on How Institutional Practices and Support Systems Support or Hinder Community College Basic Skills Students Transitioning to Postsecondary Education: A Case Study
Get PDFMany jobs in the United States have shifted to requiring education beyond high school credentials. Many potential workers are enrolled in pre-postsecondary education, or basic skills. A small percentage of students transition from basic skills to postsecondary education. Research identifies key institutional practices and supports have shown to increase transitions, but most prior research only looks at one or two practices. This single case study used an equity lens to explore how institutional practices and support systems supported or hindered student transitions from basic skills to postsecondary coursework in a comprehensive community college.
An explanatory case study was used to begin to explain how and why institutional practice and support systems in place either support or hinder student transitions. Five propositions were identified and used to narrow the scope of the study and acted like a blueprint during the data collection and analysis. Sub questions were included for each study proposition to surface institutional racism and inequality regimes at the institution. Data from interviews, observations, and document analysis were used in this study. A transition receptive culture is presented that may be used by practitioners and college administrators in developing practices and policies that support students in transitioning from basic skills to postsecondary coursework
Joy Production: Gender Euphoria in Trans University Student Lives
Get PDFMuch of our knowledge about transgender (folks who identify as not cisgender) lives in universities centers around barriers experienced, feelings of exclusion, and being victims of harassment and violence. This thesis describes conversations regarding captured gender euphoric moments from five students at a large university. They came together through a photovoice project which aimed at providing an alternative aspect of being trans: of feeling good. Photovoice provided an opportunity to reflect communally on photographs taken that capture a shared experience. Through this study, trans kinship was strengthened among the participants making the sharing of lived experience the most valuable outcome
Integrative Review of Methods for Cognitive Debiasing and Applications in Design
Get PDFDesign is a process of decision making. Organizations that are dedicated to systematic support of the design process tend to have higher profit margins. Further, studies of system development have shown that early-stage design mistakes have a large impact on incurred costs. Therefore, it is critical to identify methods to enable rational decision making in design. Research in behavioral psychology and neurocognition has demonstrated that decision making can be irrational in several predictable circumstances. The goal of this research project is to investigate the state of the art in evidence-based cognitive debiasing strategies like cognitive behavioral therapy (CBT), and translate such methods into a design context in order to facilitate more effective design decision making. To date, only a few aspects of cognitive bias have been actively explored in design research, this study provides broad review of known biases, debiasing strategies, and concludes with a suggested method for application of these methods in design
Quantitative Analysis of Mycobacterium avium subsp. hominissuis and Mycobacterium abscessus subs. abscessus Proteome in Response to Antibiotics and During Exposure to Different Environmental Conditions
Get PDFM. avium subsp. hominissuis (MAH) and M. abscessus subsp. abscessus (MAB) both belong to the clinically important non-tuberculous mycobacterial (NTM) group that infect immunocompromised patients with AIDS and individuals with underlining lung conditions such as bronchiectasis or cystic fibrosis. The main challenge of treating MAH and MAB patients is an inability to rapidly kill pathogens with multiple compounds even at the bactericidal concentrations. As a result, MAV requires prolonged treatment for 15 to 18 months and MAB is the multidrug resistant pathogenic NTM that requires treatment for 18-24 month. The need for prolonged therapy for MAH and MAB treatment influences the development of persistent and drug-resistant infections. The reason why several drugs at their bactericidal concentrations take several months to eliminate MAH and MAB infections is unknown. The main goal of our research was to investigate MAH and MAB proteome response under aerobic, anaerobic and biofilm conditions that are encountered in patient lungs and intracellularly with or without bactericidal concentrations of antibiotics. In order to
identify proteome remodeling and metabolic changes enhancing bacterial tolerance during biofilm and anaerobic conditions with or without exposure of bactericidal concentrations of antibiotics, we performed the relative protein quantitative analysis using Tandem Mass Tag Mass Spectrometry sequencing.
We identified proteome remodeling of MAH under aerobic, anaerobic and biofilm conditions in presence or absence of amikacin (4 μg/ml) and clarithromycin (16 μg/ml), and the response was compared. Overall, 4,000 MAH proteins were identified across all experimental group. In both anaerobic and biofilm conditions, MAH upregulates pantothenate and CoA biosynthesis, glycerolipid metabolism, nitrogen metabolism and chloroalkene degradation which are known to be associated with bacterial tolerance in M. tuberculosis. In anaerobic and biofilm conditions following drug treatments peptidoglycan biosynthesis, glycerophospholipid metabolism, and protein export pathways were highly upregulated.
We also identified proteome remodeling of MAB under aerobic anaerobic and biofilm conditions in presence or absence of amikacin (32μg/ml) and linezolid (128 μg/ml), and the response was compared. We found glycolysis/gluconeogenesis, citrate cycle (TCA cycle), oxidative phosphorylation, nitrogen metabolism, and glyoxylate and dicarboxylate metabolism pathways expressed exclusively in both anaerobic and biofilm conditions. Following 24h drug treatments in anaerobic and biofilm conditions, the glycerophospholipid metabolism and oxidative phosphorylation are commonly observed.
Cumulatively, our work significantly advances the knowledge on MAH and MAB tolerance mechanism in biofilms and anaerobic conditions, and how they tolerate high concentrations of antibiotics. Current multidrug regimens fail to effectively eliminate MAH and MAB infection and eradicates MAH in only 40% to 60% of individuals, and success rate for MAB treatment is only 25% to 42%. Our study has identified several novel targets that may contribute to the rapid killing of MAH and MAB
Designing Functional Materials Based on Pyrochlore Oxides: The Role of Mixed Valence and Complex Stoichiometry
Get PDFSolid state inorganic oxides play an important role in next generation electronics based on their stability, versatility, and enhanced properties over other materials. However, in order to design or tune these materials for a desired functionality it is necessary to fully understand the structure behind the properties exhibited. This dissertation explores the structure-property relationships within pyrochlore oxides through detailed structure refinements using high resolution neutron and synchrotron X-ray diffraction data as well as a thorough and systematic exploration of the resultant properties.
Osmium containing oxides are rare due to the difficulty in stabilizing complex structures with fixed stoichiometry and the metastability of the phases. Bismuth substituted thallium osmate pyrochlore samples, Tl2-xBixOs2O7-y, were synthesized using solid state reactions where the solubility limit was found to be approximately x = 1.4. Members of this solid solution were characterized by their structural, electronic, magnetic, and thermal properties to understand the influence of Bi3+ substitution on the ground state. The Os containing pyrochlores crystallize in the ideal cubic pyrochlore structure (̅3), and the lattice parameter a was found to slightly increase as a function of Bi content. A possible interplay between structure and cation valence states was explored using both neutron powder diffraction and X-ray absorption spectroscopy, suggesting that a combination of Os4+/Os5+ and Tl1+/Tl3+ mixed valency throughout the solid solution allows for the stabilization of the pyrochlore structure. The system is metallic for the entire solid solution and predominantly exhibits temperature independent paramagnetic behavior. Specific heat measurements show an enhanced Sommerfeld coefficient, a possible flat-band signature. This system gave insight into the bonding preferences of Os, indicating a dependence on high oxidation states and mixed valence for the stability of complex structures.
Next, solid solutions with the formula of Bi2-xA’xRu2O7-y (A’ = Mg, Ca, Sr; 0 ≤ x ≤ 0.2 for Mg, 0 ≤ x ≤ 1 for Ca, and 0 ≤ x ≤ 0.5 for Sr) were synthesized and characterized. The crystal structures for these phases are found to be in the pyrochlore family, crystallizing in the cubic space group ̅3 with complex A/A’ cation coordination environments. The Bi cation is found to be off-center from the ideal position due to a lone pair distortion, while the positions of substituted A’ cations vary based on the size and ionicity. The neutron structure refinements reveal a similar propensity to off-center regarding Ca and Sr, while Mg features the largest static displacement of up to 0.48 Å. Interestingly, this is one of only two known pyrochlores with Mg2+ located in an 8 coordinated site. The average Ru oxidation state for each substitution is found to increase, charge compensating for the lower divalent A’ substitution. The solid solutions show low temperature independent resistance across the series, with small changes in magnitude that scale with the amount of substitution while displaying Pauli paramagnetic behavior throughout the solid solution.
A novel series of quaternary pyrochlores with a general stoichiometry of BiCaMTeO7 (M = Cr, Ga, Sc, In, Fe) were synthesized and characterized for their structural, magnetic, and dielectric properties. A previously known analog BiCdFeTeO7 was structurally characterized for the first time. The cubic lattice parameter a shows an expected linear correlation with the average M site ionic radius for all the pyrochlore systems studied. Two representative compounds, BiCaFeTeO7 and BiCdFeTeO7, are structurally characterized utilizing high resolution synchrotron X-ray powder diffraction data revealing anion deficient pyrochlore systems which are off from the expected stoichiometry in respect to the M site. The A site of both pyrochlores are found to be moved off-center from the expected 16d site to the 96h displaced position with a magnitude of 0.25 Å and 0.22 Å for the Bi/Ca and Bi/Cd systems, respectively. The dielectric constants for the novel Bi/Ca system were found to be relatively high with a low dielectric loss and primarily independent of frequency and temperature. The magnetic measurements in the Bi/Ca system for the magnetic substitutions reveal a paramagnet and an antiferromagnet for the Fe and Cr analogs, respectively. This novel quaternary pyrochlore system shows great promise as an emerging dielectric material.
A solid solution of Pr2-xCaxIr2O7 was synthesized and characterized for the structural, electrical and magnetic properties. Samples were prepared using standard solid state synthesis and resulted in metallic materials across the solid solution. High resolution synchrotron X-ray and time-of-flight powder diffraction data were utilized to perform detailed structural work and verify the composition of the pyrochlore iridate. The structural investigation reveals that the material crystallizes in the ideal pyrochlore structure with a space group of ̅3, while the lattice constants decrease in size indicating a complicated crystal chemistry for this solid solution. The structural, magnetic and electrical measurements provide evidence towards the systematic tuning of the Ir oxidation state with increasing Ca content
Solarization in the Pacific Northwest: A Mathematical Field Model for Accumulation of Linearized Mortality from Variable Intermittent Heat
Get PDFSoil solarization trials were conducted during the growing seasons of 2016-2018 with the purpose of determining if solarization was an effective pre-planting soil disinfestation technique for tree nurseries in the Pacific Northwest. A large data set was collected on soil properties and biological indicators from 5 interdisciplinary experiments. This thesis focuses on the physical aspects of solarization to determine the parameters for success.
A mathematical model was developed and tested using the soil temperature data collected. The model was built to achieve two goals: 1) determine the soil temperature range necessary to achieve efficacy in the Pacific Northwest; 2) determine the minimum duration needed for solarization. The model was tested against field data collected on Poa annua seed mortality caused by solarization. Model tests were validated and with confidence we can say that the model can be used to predict efficacy.
Analysis of the model showed that solarization success can be assessed from only data of the maximum daily soil temperatures reached. Biological impacts depend on number of days soil temperature reaches a threshold. When 51℃+ days are achieved, the duration needed can be relatively short. 2016 was a cooler year and 6 weeks was needed to achieve weed seed mortality, while 2017 was a hotter year and only 3 weeks were required. The weed mortality field data correlates well with the number of days required above 51℃ determined by the model. With this information we can confidently say that: 1) daily soil maximum temperature is a metric that can be used to establish efficacy; 2) soil solarization is possible in the Pacific North West for Poa annua control; 3) the time window needed for solarization success is less affected by how many days the soil is covered than by which days it is covered (i.e., hot days); 4) by monitoring daily maximum temperatures, the model can be used in real time to determine when plastic should be removed
The Influence of Model Resolution on Dispersal and Retention in Oregon Coastal Waters
Get PDFLagrangian particle tracking (LPT) models are used to explore how physical processes influence the transport of particles (e.g., eggs, larvae, or propagules) in the ocean. On the Oregon continental shelf and slope, the Northern California Current System (CCS) is influenced by spatially and temporally variable coastal currents driven by weather, tides, and topography. Nearshore waters, which are sites for recreational, cultural, and economic activities, are essential to coastal communities. In Oregon coastal waters, there are five marine reserves (MRs) which range in size from 3 km2 (e.g., Otter Rock) to 37 km2 (e.g., Cape Perpetua) and average maximum depths of 18 m (e.g., Otter Rock) to 55 m (e.g., Cape Falcon, Cape Perpetua). To date, the dispersal and retention potential of these coastal MRs is poorly characterized, in part because of limited modeling studies conducted at scales that are not consistent with the size and spacing of these MRs. In past LPT model studies, particle residence times in the Oregon nearshore and shelf are less than three weeks. However, the retention of particles in the nearshore may depend on the accurate representation of smaller-scale physical processes that are not resolved in those modeling studies. In chapter 2, I developed a LPT model to examine how the spatial resolution of a Regional Ocean Modeling System (ROMS) at 2 km and 250 m affects dispersal and retention characteristics on the Oregon coast. Further, I compared the predictions of temperature, salinity, and current velocities from the 250 m ROMS to oceanographic data collected in situ to corroborate the overall trends between the model and observations. In chapter 3, I characterize particle dispersal along the
Oregon nearshore, particularly in and out of the Oregon MRs, using ROMS of different spatial resolutions (2 km, 250 m).
In chapter 2, I found that along-shelf and cross-shelf velocities are similar between the 250 m ROMS and in situ data for a majority of the domain, with the ROMS velocity higher at Heceta Bank and Cape Blanco. The 250 m ROMS tends to overestimate upwelling salinity and underestimate temperature, which may be due to an overestimation of upwelling strength (i.e., vertical velocity) in the 250 m ROMS model. A possible explanation is that the winds used to force the ROMS are higher than the observations. However, the winds at station NWPO3 are stronger than the winds used to force the ROMS (e.g., NOAA North American Mesoscale Model forecasts), making it unlikely that the higher salinity and lower temperature of the ROMS are driven by higher wind stress and consequently stronger upwelling. In simulations forced with the 250 m ROMS, particles have more meandering, a higher percentage of retention in the domain at the end of the simulation, and a greater depth range than in simulations forced with the 2 km ROMS.
In chapter 3, similarly to chapter 2, a higher percentage of particles are retained in the domain, and particles exhibit a greater depth range when forced with the 250 m ROMS. Particles forced with the 250 m ROMS travel less distance in the latitudinal direction (e.g., alongshore) and greater retention than the 2 km ROMS. However, the general spatial patterns of particle retention for the three years examined are similar between the two models, showing that it may suffice to use a lower resolution model when asking questions related to areas that retain or source particles.
This study has provided a better understanding of the influence of physical processes on particle dispersal and retention in Oregon coastal areas. The information gained by understanding regions in the Oregon nearshore that retain and disperse particles is important for the management and evaluation of the Oregon MR system
Salmon, Saws, and Sense of Place: Using a Discrete Choice Experiment to Examine Place Relationships and Preferences for Stream Restoration on the Quinault Indian Reservation
Get PDFThe social sciences have the capacity to contribute to natural resource management through investigations of human dynamics associated with the environment. Sense of place (SOP), the formed relationships between an individual and the environment, has been considered a fundamental aspect of human well-being and can contribute to more holistic understanding of people’s preferences and behaviors regarding natural resource management. In order to better understand SOP associated with the Quinault Indian Reservation (QIR) we measured the strength of this concept across different stakeholder groups. In agreement with previous literature, we found that SOP varies between groups based on amount of visitation to the reservation and participation in resource harvest. Additionally, using a discrete choice experiment we elicited preferences and willingness-to-pay estimates for stream restoration on the QIR. We showed that when making tradeoffs between restoration alternatives, SOP was a stronger factor in decision making than the actual physical environmental outcomes of restoration. We also identified some social benefits from restoration. These results contribute to SOP theory by applying a quantitative assessment to tribal groups and assessing SOP influence on restoration preferences. In its entirety, the research could influence Quinault management’s decision making as we highlighted some important human factors associated with the reservation environment
The impacts of ionization chemistry on hydrocarbon detonation
Get PDFAs carbon emissions are negatively impacting ecosystems across the globe, researchers are in a race against time to provide cleaner and more eÿcient power. Detonation engines can help meet the increasing demands for cleaner and more eÿcient power generation by providing an alternative means to use oxy-fuel combustion for carbon sequestration. By pairing a detonation engine with a magnetohydrodynamic (MHD) generator, power can be directly extracted from the ionized gases behind the detonation front via the Lorentz force. This eliminates the moving components found in gas turbine engines, which are unable to withstand high temperatures encountered in oxy-fuel combustion. The electrical conductivity of the ionized gas behind the detonation front can be increased by several orders of magnitude with the addition of readily ionizing seed particles such as potassium, increasing the power generation of the engine. However, this increase has a limit as dilution studies have shown decreases in detonation speeds with increasing diluent. To better understand the interaction of seed particles with the detonation front and the electrical conductivity of the mixed gas, a detailed hydrocarbon kinetic model has been created in conjunction with a detonation solver. This model is, to my knowledge, the first detailed hydrocarbon model to be used in detonation simulations. I used this model to study the parasitic interaction arising from using potassium seed material. I found that the ionization of the seed particles negatively impacted detonation velocities up to 8% and power production up to 15%, pointing to the need for further research development into detonation kinetic models and ionization fields