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Innovative Assessment Tests and Indicators for Performance-Based Asphalt Mix Design
No full textAsphalt mixes are designed to provide adequate resistance to various distresses including cracking, rutting, and moisture damage. Recently, more efforts are directed towards including performance assessment tests during the design and production of asphalt mixes. Performance-Engineered Mix Design (PEMD) or Balanced Mix Design (BMD) is a new and innovative design approach that incorporates performance assessment tests to optimize the design of asphalt mixes to provide adequate performance. Although transportation agencies are motivated to implement the PEMD approach, several research knowledge gaps and concerns need to be addressed before PEMD successful implementation. This research study aims to advance, develop, and implement performance-engineered design approach and specifications to extend the service life of asphalt pavements. The first phase of this research developed and evaluated a new and innovative monotonic cracking performance indicator called Weibull Cracking Resistance Index (WeibullCRI). The proposed indicator describes the entire load-displacement curve, which overcomes the limitations of the existing performance indicators. First, WeibullCRI was examined using an extensive laboratory evaluation of 16 different asphalt mixes. The results indicated that WeibullCRI was sensitive to variation in binder content and binder PG and the results were in good agreement with the expected cracking resistance based on the composition of the studied mixes. In addition, WeibullCRI had low variability in test results and higher number of various statistical groups. Next, the applicability of WeibullCRI as a unified approach to analyze the results of various monotonic assessment tests was investigated using data generated by other researchers and reported in the literature. The results indicated that WeibullCRI is able to interpret the testing results of various monotonic performance assessment tests (i.e., IDT- intermediate temperature, Semi-Circle Bending [SCB]- intermediate temperature, SCB-low temperature, Disk-Shaped Compact Tension [DCT], and Simple Punching Shear Test [SPST]) and various displacement measurement methods (i.e., actuator vertical displacement and Crack Mouth Opening Displacement [CMOD]). WeibullCRI was also sensitive to variation in test conditions (i.e., specimen notch depth, thickness, and air void content) and mix composition proportions (i.e., binder content, binder grade, aggregate type, NMAS, aging, rejuvenator dosages, and Recycled Asphalt Pavement [RAP] materials). The second phase of this study reviewed and evaluated the current monotonic cracking performance assessment tests and indicators including the developed WeibullCRI used to assess asphalt mix resistance to cracking. In this phase, the testing requirements of various test standards, key publications, concepts, calculation methods, physical meaning, and advantages and disadvantages of various performance indicators were reviewed. Then, the study investigated the validity of the most promising testing standards and indicators. Three testing standards and 12 performance indicators were considered. Several aspects were examined including 1) investigate the fundamental meaning of the variation in the load-displacement curve in terms of the change in mix resistance to cracking, 2) sensitivity of performance indicators to mix compositions, 3) variability in test results, 4) number of various statistical groups, 5) correlation between various performance indicators, 6) direct correlation between laboratory results of monotonic performance tests and indicators with the observed field cracking, and 7) ability to develop PEMD specifications. A comprehensive laboratory investigation was conducted using 33 different asphalt mixes included six Laboratory Mixed-Laboratory Compacted (LMLC) and 10 Plant Mixed-Laboratory Compacted (PMLC) asphalt mixes, and 17 field projects with known cracking performance. The results showed that WeibullCRI calculated from the IDT test to have the lowest test variability, maximum number of Tukey’s honestly significant difference (HSD) groups, and have excellent correlation with cyclic cracking resistance assessment indicators as compared to the other monotonic performance indicators. In addition, the results demonstrated that there was no direct correlation between all monotonic performance indicators and the observed field cracking performance, therefore an alternative approach was proposed, evaluated, and validated to develop performance thresholds for the selected performance indicators. Three pass/fail cracking performance thresholds were proposed for WeibullCRI to distinguish between asphalt mixes with good, fair, and poor cracking resistance using the proposed approach. The third phase of this study focused on the development and evaluation of a new cyclic cracking assessment test called Multi-Stage Semi-circle bending Dynamic (MSSD). The test offers advantages over the available monotonic and dynamic cracking assessment tests and addresses major concerns to implement the PEMD (i.e., performance test validity, complex specimen preparation, and testing time). The developed MSSD test simulates the repeated loading (cyclic) in a reasonable testing time (less than 9 hours per test regardless of mix type), has a fixed loading sequence that works for mixes with different characteristics (e.g., mix composition, percent air void content, thickness, etc.), and utilizes testing equipment and specimen geometry similar to that used in monotonic tests. The laboratory evaluation results showed that the proposed test and its derived performance indicators were sensitive to mix composition and had lower variability compared to other dynamic tests. In addition, the MSSD performance indicators correlated well with the observed cracking performance in the field and were able to distinguish between projects with good and poor resistance to cracking. Based on the evaluation results, three pass/fail cracking performance thresholds were proposed to distinguish between asphalt mixes with good, fair, and poor resistance to cracking. The fourth phase of this research examined the most promising tests and performance indicators to evaluate the resistance of asphalt mixtures to rutting. Two tests (i.e., Hamburg Wheel Tracking test [HWTT], and Asphalt Pavement Analyzer [APA] rut test) and three rutting performance indicators (i.e., HWTT rut depth after 15,000 passes [HWTT15000], HWTT rut depth at 20,000 passes [HWTT20000], and APA rut depth after 8,000 cycles [APA8000]) were considered. An intensive laboratory investigation was conducted that included six LMLC, 10 PMLC, and field cores extracted from 17 field projects. The research findings showed that both HWTT and APA rut test provided similar rutting assessment for the evaluated mixes. The study recommended using the HWTT over the APA rut test since HWTT can be also used to assess the resistance of asphalt mixtures to moisture damage to moisture damage. Also, the study recommended using HWTT15000 over HWTT20000 as a performance indicator since it requires less testing time. The final phase of this research provided recommendations of the best testing standards, performance indicators, and performance specifications to assess asphalt mix resistance to cracking and rutting. In addition, it provided guidelines to demonstrate the use of the proposed tools during the design and/or production of asphalt mixes. It also proposed standards testing procedures for the newly developed WeibullCRI performance indicator and MSSD test.doctoral, Ph.D., Civil Engineering -- University of Idaho - College of Graduate Studies, 2019-1
Ethical Frameworks of Our Moral Obligations to Climate Change: Advancing Policy through Philosophy
No full textClimate change is a wicked problem. It is also a multi-faceted, interdisciplinary problem and needs to be understood as such to be solved. In this dissertation, I look at the ethical aspects of climate change to understand how ethics plays a role in the formation of policy and public opinions and perceptions. First, I consider how various ethical frameworks can change the structure of carbon mitigation policy by analyzing the Kyoto Protocol and the Paris Agreement. The former structures carbon mitigation with rule utilitarian appeals, the latter uses virtue ethics and an appeal to reputation. Both aim for international carbon mitigation, but each choose unique ethical frameworks to structure how this is to be achieved. Other groups appeal to ethical frameworks in their mitigation strategies as well. For example, C40 Cities Climate Leadership Group, a conglomeration of cities working together to make their cities more carbon neutral, appeals to virtue ethic ideas. Governments—whether knowingly or not—appeal to ethical frameworks to evoke change. Some frameworks might do this better than others, so I seek to uncover what the effects of using varying ethical frameworks in policy formation might be. Then, I consider whether individuals find certain ethical frameworks more appealing than others when used as reasons we should reduce the effects of climate change. After all, ‘ethics’ can be a vague term. If one were to frame an issue as ‘ethical’ there would be many ways to do this. In the same vein, it is unclear which ethical frameworks Americans make use of when considering climate change as an ethical issue. I consider three popular normative ethical frameworks. There are three common frameworks by which once can justify a right action. Deontology focuses on following principles or one’s duty; utilitarianism focuses on maximizing favorable outcomes (or minimizing unfavorable outcomes); and virtue ethics focuses on the moral agent’s exemplification of excellent character. I use these three frameworks to frame messages about the individual’s ethical obligation to reduce the effects of climate change. In a nationally representative survey (n=1,202) I gauge Americans’ level of agreement to each statement, and determine which statement is most persuasive. By doing this, I investigate which ethical frameworks are most suitable for sub-groups of the American public. Results show that agreement with a deontological message is positively correlated with religiosity (p≤0.01). Further, with an increase in religiosity, there is a higher likelihood that a respondent will self-report that the deontological message is more persuasive than the utilitarian message (p≤0.001). These findings suggest that specific ethical frameworks have more persuasive appeal among some groups over others. I specifically show that there is an ethical reason to mitigate that the religious—a traditionally skeptical group concerning climate change—responds to. Next, I further consider some nuances of Americans’ perceptions of climate change as an ethical issue. I measure whether (1) climate change beliefs are seen as ethical, and whether (2) decisions made to address climate change are seen as exercises in moral decision-making. While seemingly counter-intuitive, it is possible to think climate change has ethical ramifications without thinking it is human-caused or a serious problem. This and other findings are discussed, as well as what this means for future research. This dissertation exemplifies how ethics can influence climate policy structure, and therefore its potential adoptability and implementation. I also show how ethics can be used as a message framing device to increase acceptance of climate change messages among skeptical groups. Lastly, I give insight into some nuances and specificities of Americans’ ethical perceptions of climate change. This research offers some new ways to use ethics as a tool to further understand and make applicable climate change ideas and objectives.doctoral, Ph.D., Environmental Science -- University of Idaho - College of Graduate Studies, 2019-0
Optimization Problems in Computational Physics: from Atoms to Molecular Assemblies
No full textComputer simulations are an invaluable tool in physics to help understand underlying mechanisms and explore parameter space without the need to perform costly experiments. This dissertation outlines two optimization problems in computational physics. The first is using molecular modeling to estimate the free energy---a fundamental physical quantity. The second is using finite element analysis to design a superconducting magnet system that could be used to efficiently store energy. As a measure of the amount of energy available to do work, the free energy is important for understanding, e.g., how amino acid mutations affect protein-protein interactions or designing new drugs. Here, we present an implementation of the Monte Carlo adaptive integration method (AIM) in the popular molecular dynamics software package, GROMACS. We use AIM to calculate free energies in two model molecular systems and compared these results against a suite of standard methods. We show that AIM converges with less simulation time than standard methods. We have also investigated the use of Halbach magnet arrays in combination with high-temperature superconductors for magnetic levitation of a fly-wheel energy storage system. Halbach arrays were selected because they have properties that are expected to be beneficial for efficient energy storage. To find the optimum orientation of the magnets for the arrays, we used Infolytica Magnet, a finite-element computation software package, to iterate over all permutations of magnet arrays consisting of 3 and 5 magnets in single and double layers. The fields and levitation forces as well as the width of the magnet arrays relative to the width of the superconductor were analyzed. We present our findings for the optimal array of this type and suggest guidelines to increase the levitation force of a superconducting magnetic bearing.doctoral, Ph.D., Physics -- University of Idaho - College of Graduate Studies, 2019-0
Training and Supporting General Education Teachers to Promote Inclusive Practices
No full textLearners with autism spectrum disorder (ASD) and other disabilities should have access to the general education curriculum with their typically developing peers. Common barriers to inclusion can be addressed, in part, through effective in-service training on evidence-based practices (EBP). The purpose of this research was to assess the effects of distance education webinars and video-based performance feedback through Behavior Imaging™ technology on the acquisition of general education teachers’ use of two evidence-based practices, behavior-specific praise, and prompting, in rural classrooms. The Behavior Imaging™ technology allowed the general education teachers to self-video record instructional sessions in the classroom through iPads. The resulting videos were uploaded to a secure server where the researcher viewed the taped sequences, tagged examples and non-examples, and wrote corresponding corrective feedback. This was the first known study to use the Behavior Imaging™ technology for teacher preparation in an applied setting. In a multiple element, multiple baseline design across behaviors (praise and prompting) with three general education classroom teachers, results showed that the training webinars had little effect on teacher behavior, but video-based feedback produced increases in the correct use of praise and prompting when associated with a systematic instructional sequence (call for a response, pause, prompt, child response, praise or correct). Negative comments decreased to near zero levels across participants as they increased their correct use of behavior-specific praise and prompting. The participants in the study stated that the technology was easy to use, that their participation was worth their time, it changed their teaching practice, benefited all students, and fostered a more positive classroom environment.doctoral, Ph.D., Curriculum & Instruction -- University of Idaho - College of Graduate Studies, 2019-0
RESPONSE OF IMPROVED WESTERN LARCH SEEDLINGS TO DROUGHT STRESS AND SITE QUALITY
No full textTree improvement remains a valuable and effective way to increase growth and yield in commercially valuable timber species. Significant results have been found in the manipulation of genetics for Pseudotsuga menziesii in the northwestern U.S, Pinus taeda in the southeastern U.S, Pinus raidata in New Zealand, and Pinus sylvestris L. in Europe. Unfortunately, it still remains unclear how western larch performs in genetics trials. Endemic to the Inland northwest and valued primarily for its rapid growth and superior wood quality, western larch is widely planted and managed with intensive silvicultural regimes. In an effort to gain a better understanding of the performance of improved western larch in the field, members of the Inland Empire Tree Improvement Cooperative (IETIC) established a western larch seed orchard in 2007 with families from superior-rated trees. The orchard serves to produce open-pollinated seed for reforestation of cooperative member lands and identify desirable candidates for continued breeding. Seed from seven individual half-sib families in the orchard, selected across a range of regional climates, was collected in 2016. One open-pollinated bulk orchard lot was also collected for this study. Seed was sent to the University of Idaho Pitkin Forest Nursery in 2017 where it was grown and then out-planted the following year for field testing against various site climates and qualities. In 2018, individual families were grown from seed in a greenhouse study to examine genetic by soil moisture effects on seedling morphology and physiology. The greenhouse drought study was arranged as a Complete Randomized Block Design, with four treatments of increasing drought severity including a well-watered control. Seedlings were germinated in germ cloth, transplanted into D25L Deepots, and then well-watered until secondary leaves flushed. From second leaf flush, the drought trial was applied for 10 total weeks. Seedlings were held at specific gravimetric water contents based on a moisture release curve for the growing media. Three rounds of gas exchange and destructive sampling were conducted in order to obtain photosynthesis, transpiration, specific leaf area, above ground biomass, belowground biomass, and root mass fraction. Height and stem diameter were measured weekly. Results from this study revealed a family and treatment effect on all morphological features, indicating superiority of certain families for drought tolerance during early seedling development. Aboveground development, in mass, height, and stem diameter, and belowground root development were reduced with increased drought intensity. Physiology followed common trends with decreasing photosynthetic and transpiration rates with increased drought severity. Specific leaf area also decreased with increasing drought intensity, indicating increased tissue density. Overall, there was no mortality which could be based on various factors, one of which is high overall water use efficiency in improved stock. Family differences in the morphology indicated some level of drought tolerance within certain seed lots, which could prove advantageous for out-planting performance at drier sites. The field study was arranged as a Random Complete Block Design, ranging across three different sites each belonging to members of the IETIC and the Intermountain Forestry Cooperative. Each site was selected based on varying soil parent material and moisture regimes. Data collected from the out-planting trial included seedling height, root collar diameter, soil volumetric water content, soil bulk density, soil chemistry, competing vegetation cover, vertical vegetation next to seedlings, and slash loading. Site, soil moisture, and competing vegetation were the most significant factors effecting height growth. There was no family effect on height or diameter. Seedlings at the drier site, Stimson, outperformed seedlings at the wetter site, Molpus, however, Molpus was also the last to be planted and had lower June through August average air temperatures. Total forbs had a negative correlation to height growth as seedlings competed for soil moisture and nutrients. Height of nearby competing vegetation had a positive correlation with seedling height growth. The results from this experiment should be considered short-term findings, however, as it stands they indicated that there is no superiority between families and that half-sib breeding control does not outperform an open-pollinated bulk lot based on site conditions.masters, M.S., Natural Resources -- University of Idaho - College of Graduate Studies, 2019-0
Investigation of genetic diversity of Grapevine leafroll-associated virus-3 and Grapevine red blotch virus in Idaho grapevines
No full textWine grape production has steadily increased since planting of grape vines began in the 1870s. Although wine grape production is a relatively young industry within Idaho, the state now has over 50 wineries and an annual economic impact of nearly $170 million. Due to the significance of the industry to Idaho, it is important to understand the presence and diversity of viruses associated with diseases of grapevines that may put the industry at risk. The most common of these diseases is the grapevine leafroll disease caused by a complex of Grapevine leafroll-associated viruses (GLRaV), of which the most prominent is GLRaV-3. In Idaho, a novel genetic variant of GLRaV-3 was identified in separate vineyards infecting different wine grape cultivars. Recently, a new virus was also identified in Idaho vineyards for the first time, Grapevine red blotch virus (GRBV), already widely present in California, Washington, and New York. It is important to understand the characteristics of these viruses, the effects on vine health, and to develop methods for detection. Here a preliminary study of the GLRaV-3 and GRBV genetic diversity in Idaho is presented. The development of detection methods for screening of planted and nursery stock vines can have a substantial impact on the wine industry to ensure planting of virus-free stock and/or economical and agronomic reasons to remove infected commercial plantings.masters, M.S., Plant, Soil and Entomological Sciences -- University of Idaho - College of Graduate Studies, 2019-0
Coffee Roasting Process Monitoring with In Situ NIR Spectroscopy
No full textThere is a need in the roasting industry for better real time feedback during roasting to consistently achieve the desired qualities in roasted coffee, and NIR spectroscopy has shown some promise for this purpose. This project generated a new roast degree scale based on in situ NIR prediction of the cracking sounds which are commonly used as a real time indication of roast degree. This required measuring the start and end times of the two crack events by analyzing recorded audio from a large set of roasts including eight varieties of coffee with four roast temperature profiles each. An NIR spectrometer with a custom diffuse reflectance probe attached to the roaster recorded in situ spectra during each roast for predicting the crack event times and determining the roast degree. Measurements of coffee acidity provided a basis for comparing the newly developed crack scale to two other scales: a simple scale generated based on NIR absorbance and the common CIELAB scale based on visible color. Both NIR based scales performed better than the visible scale in this comparison, and the simple NIR scale performed best. This scale was then used as a basis for determining the effects of different roast temperatures on acidity, to explore the ability to control acidity independent of roast degree. A new set of constant temperature roasts provided the dataset for this analysis, resulting in simple linear relationships between roast degree, roast time, and acidity.masters, M.S., Chemical and Materials Science Engineering -- University of Idaho - College of Graduate Studies, 2019-0
Molecular Systematics Large and Small: Patterns of Evolution in Lamourouxia and Orobanchaceae
No full textunfinishedmasters, M.S., Biology -- University of Idaho - College of Graduate Studies, 2019-0
EVALUATION AND MODELING OF PAVEMENT MARKING CHARACTERISTICS BASED ON LABORATORY AND FIELD DATA
No full textDrivers rely on the visibility of pavement markings to maintain a safe road path especially during nighttime and challenging weather conditions. With the growing demand for pavement marking materials, durability and long-term weatherability of these products is critical. Current performance evaluation methodology using field test-deck protocols requires significant time and resources, and under these protocols the performance of a pavement marking can be monitored for a period of up to three years. In addition, safety-related issues such as exposing technical staff to road hazards while applying the marking materials and collecting measurements, along with road closure consequences, are of concern. The primary objectives of this research were to develop an accelerated laboratory-based procedure that could evaluate the performance of pavement markings, overcome the shortcomings of current evaluation practice, and investigate the safety performance of pavement markings based on existing crash data and results from a driver simulation study. For the laboratory-based procedure, a three-wheel polisher device (TWPD) and xenon arc chamber (XAC) were employed to replicate varying traffic, snowplowing, and weather conditions. The deterioration of the physical measurements (i.e., dry and wet retroreflectivity, color change, and durability) of waterborne and thermoplastic markings was modeled. All of the performance measures logarithmically deteriorated under different TWPD loadings, except for the durability of the thermoplastic markings which followed a linear degradation function. A significant reduction in percent retroreflectivity was observed in the initial part of the TWPD testing but leveled out as the number of cycles increased. This deterioration pattern is similar to what occurs in the field, as retroreflectivity dramatically decreases after the first few months of installation and then stabilizes before the end of its service life. On the other hand, a linear increase in retroreflectivity and color change occurred during the artificial weathering exposure time (i.e. 2,000 hours) due to the change in surface physical properties. The color analysis revealed an important relationship between pavement marking retroreflectivity and color change. After traffic loading, all colors darkened due to the exposure of the black asphaltic color or the abrasion of the upper layer of marking, and in turn retroreflected less light while different color change patterns were experienced under the artificial weathering. The color analysis results showed that when a color closely resembles white, the sample retroreflected more light. The TWPD and weatherometer effectively simulated and accelerated the operational and environmental effects (e.g., traffic, snowplowing, sunlight, moisture, and temperature) so that assessment of pavement marking performance could be completed in an abbreviated time frame. The results yielded a significant relationship between all performance measures assessed in both the laboratory and field. Evaluating the performance of pavement marking products using an accelerated laboratory-based procedure provides a department of transportation (DOT) with a flexible tool to cope with the rapidly evolving industry through the establishment of guidelines that might be used for the selection and maintenance of the pavement markings. This procedure can be used to compare different marking materials and assess marking materials whether they bear severe traffic operating conditions or harsh climates before implementation. To assess the safety performance of pavement markings, specifically on two-way, two-lane rural roads which are common in the state of Idaho, two separate approaches were adopted. First, a crash analysis study over eight years (2010-2017) on rural roads in Idaho was conducted to understand the relationship between retroreflectivity deterioration of edgelines and crash occurrence. Field retroreflectivity data for waterborne edgeline markings from thirty-eight sites were collected and modeled over twelve months across six districts with different environmental conditions. The results yielded a logarithmic relationship between retroreflectivity and age, and pavement markings in districts subjected to higher ground snow loads deteriorated faster than those with lower ground snow loads. This faster deterioration trend in northern districts was attributed to winter maintenance activities and harsh weather. Even though, a clear statistical pattern was determined for District 1, which was subjected to the higher ground snow loads among all districts, the methodology used in this study could not definitively conclude that crash rate increased with lower edgeline retroreflectivity. Second, a study using the University of Idaho’s driving simulator was implemented to evaluate the safety effects of different edgeline pavement marking widths (e.g., 4-inch and 6-inch) and deteriorations (e.g., 0%, 25%, 50%, and 75% deterioration) on driver behavior. The results indicated that statistically significant differences were observed during nighttime conditions when comparing the driver’s lane deviation (vehicle’s lateral position) between the wider 6-inch longitudinal edgeline pavement markings and standard 4-inch edgeline marking. Drivers consistently maintained a lane position that slightly favored the edgeline side when exposed to a 4-inch marking and increasingly shifted away from the centerline as edgeline deterioration worsened. The results of the statistical analysis implied that 4-inch markings and severely deteriorated pavement markings cause higher variation values in driver lateral position which in turn could affect overall driver safety. This research benefits transportation agencies, particularly those sited in cold-weather regions, by enabling them to predict the deterioration of marking materials and assist in the scheduling of maintenance marking projects to maximize the operational and safety benefits of the existing material. This research also make recommendations with regard to a minimum retroreflectivity threshold that should be maintained for pavement markings of two-way, two-lane rural roads and the use of wide pavement markings.doctoral, Ph.D., Civil Engineering -- University of Idaho - College of Graduate Studies, 2019-0