1925 research outputs found
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Uncoordinated and price incentive based load profiles due to electric vehicle charging
No full textThis research aims to build data-based, statistical model that can develop the load profile generated by uncoordinated charging of electric vehicles in the grid. The model development was accomplished by carrying out a literature review on electric vehicle technologies, electric vehicle utilization habits, and the trend in the rise of the number of electric vehicles sold in the automobile market. The load profile generated is intended for use in the production cost modeling of the electric system in order to learn about the possible threats and opportunities that could be caused by electrification of the transportation system. The model was implemented in MATLAB using Monte Carlo simulation, which uses random sampling of charging parameters like an initial state of charge, the final state of charge, charging types and start time of charging, for the number of electric vehicle charging events coupled in the grid. These charging parameters are modeled using statistical probability density functions based upon data collected from a fleet of actual electric vehicles. Production cost modeling was carried out using the software PSO which uses the CPLEX to solve its optimization problem. The optimization problem was formulated as the mixed-integer linear program considering the DC power flow model with an objective to minimize production costs subject to constraints. The test system used for the production cost modeling was the NAU 5-bus system which is a modified form of PJM 5-bus system. Production cost modelling tests were carried out for three different days. A time of use rate which incentivizes EV owners to charge at non-peak hours (though otherwise uncoordinated) led to a decrease in the operating cost of the system when compared to uncoordinated charging behaviors on all the days considered for the test
Scholartistry and intentionally extracurricular professional development: research puzzles accessed through memoir
No full textABSTRACT
SCHOLARTISTRY AND INTENTIONALLY EXTRACURRICULAR PROFESSIONAL DEVELOPMENT: RESEARCH PUZZLES ACCESSED THROUGH MEMOIR
By Megan Carole Walker
The main goal of this self-study was to engage in arts-based research (ABR) for the purposes of promoting open-ended wonderings connected to teacher knowledge and teacher development. In order to conduct this ABR research, I stated explicit subjectivity by situating myself as sole participant in this context-specific self-study. The ABR work of generating and analyzing data for this study allowed me to construct and analyze a memoir surrounding my stories of lived experience working to co-found and develop and outdoor leadership academy for middle school students. To provide focus for this study, I developed a term to describe the activities surrounding my work as teacher, co-founder, and program developer by doing work connected to student achievement that was not required of me and ultimately contributed to my professional development: intentionally extracurricular professional development (IEPD). The data generated and analyzed for this ABR study was constructed in accordance with the Guiding Principles for conducting ABR (Cahnmann-Taylor, 2018) and the seven features of ABR (Barone and Eisner, 1997). Throughout the data construction and analysis, two main themes emerged. The first theme connects to how my avocational activities fed my teaching practices and vice versa. The second theme connects to issues surrounding my distractions during a time of increasing level of threats to school safety. From these themes, research wonders developed beyond the self, yielding suggestions for further research into the stories of lived experience of teachers connected to ABR and IEPD
Ichnology of the Bright Angel shale formation, Grand Canyon, Arizona: indicators for Middle Cambrian paleoecology
No full textThe Cambrian Explosion represents a major diversification event for early life that ultimately led to the evolution of modern organisms. Most studies have focused on the remarkable examples of soft-bodied preservation in localities such as the Burgess Shale, Chengjiang, and Sirius Passet. However, studies on the Cambrian ichnological record are lacking. The Bright Angel Shale in Grand Canyon, AZ provides an extensive Middle Cambrian trace fossil record that has been poorly studied. This project aims to redress that gap by studying the trace fossil record of the Bright Angel Shale and relating it to the known record of body fossils in order to add to the understanding of Middle Cambrian shallow marine paleoecology. Fifteen stratigraphic sections, with their corresponding bioturbation index, were measured in the Bright Angel Shale at eleven localities in eastern and western Grand Canyon. Three lithofacies were identified comprising the heterolithic facies, cross-stratified to massive sandstone facies, and maroon sandstone facies. Bioturbation is generally high and ranges significantly throughout the Bright Angel Shale stratigraphic sections showing some cyclicity in eastern Grand Canyon and abrupt changes in western Grand Canyon. Fifteen ichnogenera were identified throughout these sections including three ichnospecies. Ichnogenera were semi-quantified by counting their occurrence in horizons vertically at each stratigraphic section with their corresponding lithofacies and bioturbation index. The trace fossils were also systematically described, each with a discussion on their potential trace makers of known fossils from other Cambrian strata. The eastern Grand Canyon contains higher ichnodiversity, while the west has low ichnodiversity. In both regions of Grand Canyon, Palaeophycus and Teichichnus are the most common ichnogenera. All ichnotaxa from the Bright Angel Shale represent the Skolithos and Cruziana ichnofacies. The depositional environment of the Bright Angel Shale most likely consisted of a tide- and wave-dominated, shallow marine shelf with estuaries, tidal channels, and tidal flats that were often influenced by storm and tidal energy. Potential trace fossil producers of the Bright Angel Shale reveal the prevalence of vermiform organisms such as annelid and priapulid worms. These worms have been identified in the Burgess Shale and Chengjiang lagerstätten, but their record is very small compared to the preponderance of arthropods. The Bright Angel Shale also contains a record relatively high in arthropods, but lacks any record on worms. Overall, the preponderance of vermiform trace makers in the Bright Angel Shale based on the trace fossil record adds to the Cambrian story that worms may have been much more abundant than previously thought
Physiological response of grassland species to variable water supply and demand
No full textThe US Southwest is predicted to experience longer periods of drought with more intensive monsoonal precipitation during the summer months in the near future. These changes in precipitation may drastically alter grassland ecosystems in terms of community composition, net primary production, and physiological performance of plants. Greater precipitation and increased soil moisture allow plants to uptake more water and open their stomates, allowing for gas exchange. Conversely, greater vapor pressure deficit (VPD) typically corresponds with the closure of stomates to protect xylem from cavitation due to excessively negative osmotic pressure. By experimentally altering summer precipitation in grassland ecosystems ranging from desert scrub to mixed conifer forest meadows, we provide lines of evidence that suggest that the interactive effects of soil moisture (water supply) and VPD (water demand) do affect the stomatal conductance (gs) and gas exchange strategy of dominant species. As expected, soil moisture was positively correlated with gs while VPD showed a negative correlation across all ecosystem types. Lower elevation ecosystems were typically more regulated by water demand, where grasses and displayed an avoidance strategy to increased water demand by closing their stomates to conserve water and avoid xylem cavitation. Grasses become less water limited with increasing elevation and do not regulate gas exchange as tightly with increasing VPD. In the systems where the interactive effect of water supply and demand was a significant predictor of gs variance, higher elevations switched from an avoidance strategy with increasing VPD, to a tolerance strategy, increasing gs when both water supply and demand are high. The results of this study indicate that the interactive effects of water supply and demand will be crucial predictors of ecosystem response to changing climates, and the strategies employed by plants will vary with elevation and ecosystem type
Adobe New Media Lab documentary: resist, reclaim, and revitalize indigenous identities
No full textTribal educators and institutions of higher learning should design New Media Labs (NML) that will help them revitalize North American Indigenous identity via the production of video and audio documentaries. To help them decide whether they should take this action, this study employed a quantitative before-and-after matched pairs T-test survey. This study reported statistically significant motivational difference among Keetoowah tribal members who participated in the Indigenous revitalization video survey. It was important to consider literature that explained the generational trauma that has been caused by American assimilation policies and described how that experience was shared among many tribal members. The study examined the literature that explained how tribal educators and institutions of higher learning can effectively develop projects that promoted and empowered tribes to reclaim their unique cultural identities and exercised their rights of inherent sovereignty
Effect of a freshman academy on academic achievement and attendance
No full textFreshman students adjusting to the academic rigor and requirements of high school face academic and attendance issues. School districts have researched and developed structures to prepare for ninth graders as they enter high school and have chosen to separate freshmen from the older cohorts of students as one method to provide support. This study examined the role of setting among 234 high school freshmen and the relationship that setting plays in academic achievement and attendance.
For this ex-post facto causal comparative study, 234 high school freshmen students in two suburban Arizona high schools within the same school district were studied. There are two groups under comparison-one received the treatment (freshman academy) and one who did not receive the treatment during their ninth grade year of high school. The independent variable of setting and the dependent variables of AzMERIT math test results and year-end attendance results for the two groups of participants were tested. The co-variables were ethnicity and gender. The data was analyzed using a one-way and a two-way ANOVA.
The results from this study indicate that there are no significant interactive effects between the setting and the academic achievement or attendance for the students attending the freshman academy. Setting did have an interactive effect on AzMERIT math test results and year-end attendance results for the traditional high school students. Although most of the data collected was not significant to support the hypothesis, it is recommended that the results of this study are used to inform modifications of current academy practices to further research additional practices to support students in a successful beginning of high school
Understanding vertical and lateral changes in sand-wave facies in dilute pyroclastic density current deposits
No full textMaar-diatreme volcanoes commonly produce sand-waves with features that resemble bedforms found in eolian and fluvial deposits, causing difficulty in distinguishing the origin of a deposit, particularly when geologic context is lacking. Bedforms in eolian and fluvial environments have been extensively studied but information is sparse in pyroclastic environments. Pyroclastic deposits from Teshim Butte, Triplets Maar, and Haskie Volcano, located in the Hopi Buttes Volcanic Field AZ as well as Zuni Salt Lake Maar, Afton Craters located in New Mexico, and Ubehebe Crater located in Death Valley California, were studied to define vertical and lateral changes within the sand-wave facies. Stratigraphic sections, grain size, and bedform properties were measured in the field and with photogrammetry and analyzed statistically. Six bedform types were identified and defined based on their physical characteristics. The six types are: small, erosional, elongate, medium type one, medium type two, and large bedforms. Estimate for flow depth and velocity were calculated based on bedform attributes. Key features unique to volcanic bedforms include: low lee-side angles, the co-deposition of coarse and fine material, rapid changes in bedform type, low amplitude bedforms, highly variable wavelengths, and the formation of bedforms with crests and stoss sides preserved. Lee-side angles for volcanic bedforms measured in this study were typically below the angle of repose. Deposition that occurs on the lee slope of volcanic bedforms is not necessarily dependent on gravity-driven avalanches as in eolian and fluvial dunes. Due to the pulsating nature of pyroclastic deposits, bedforms commonly occur as singular features, so each bedform is independent of other bedforms. Fluctuating energy, existing topography, and supply of eruptive material can lead to the six sub-facies occurring in a single vertical section. Depending on location and depth of the explosion loci within the maar-diatreme, bedforms contain juvenile material mixed with lithic material. Bedforms from this study can be used to help in identification of depositional environments in locations where context is lacking or minimal data are available, such as remote sensing studies of bedforms on Mars
Climate has a larger effect than stand basal area on wood density in Pinus ponderosa var. scopulorum in the southwestern USA
No full textContext:
Forest restoration treatments in the U.S. Southwest are generating large quantities of small-diameter logs. Due to negative perceptions about ponderosa pine wood quality, this material is often seen as a “waste disposal” problem rather than a high-value resource.
Aims:
Our objective was to understand more about variation in southwestern U.S. ponderosa pine wood density, an important indicator of wood quality. Specifically, we investigated the effect of stand basal area on wood density, and the effect of annual and quarterly climatic variation on wood density.
Methods:
We collected samples from 54 trees grown at six different basal area levels from a replicated stand density experiment. Pith-to-bark strips were used in an X-ray densitometer to obtain annual density and growth measurements from 1919 to the present
Principals’ perception of the effectiveness of a standards based principal evaluation system
No full textThis study investigated K-12 school principals’ perception of their standards based evaluation system. A case study methodology was used to investigate, describe, and analyze the perceptions of twelve school principals serving across five regions in one southwestern school district. The following questions guided this study: How do principals utilize the standards to shape their leadership practice? What role does the principal play in their own evaluation? What are the strengths and weaknesses of the standards based evaluation system? How might the standards based evaluation system be improved?
The primary sources of data collected and analyzed were generated by in-depth semi-structured interviews with the participants. Additional data analyzed were memos, field notes, and artifacts which included the district policy regarding the evaluation of principals and the principal evaluation instrument. The data were organized and analyzed through the framework of the research questions and sub-questions related to principal perceptions and interaction with their standards based evaluation. Strategies used to analyze the data consisted of organizing the data, coding, memoing for emergent ideas, theming, interpreting, and representing the data. Validity was addressed using triangulation, bracketing interviews, transcript checking, member checking, and an external audit. Cognitive interviews, triangulation, and external audit were used to demonstrate reliability in this study. This study had limited generalizability because only the perceptions of school principals in one southwestern school district were analyzed.
The following major findings emerged from this study relative to principal participant perceptions of their individual standards based evaluations. The principal participants were unable to list the standards by name; however, the standards were aligned to their top three priorities. The data also revealed that the majority of the principals were not focused on their standards based evaluation system to drive their priorities or leadership actions. Subsequently, more than half of the principal participants believed that the standards had no impact on their leadership capacity. Most of the principals in this study reported that they did not have strong relationships with their supervisors, which they believed was elemental to their standards based evaluation system. The lack of interactions translated into a one-sided compliance requirement by the principals when addressing their evaluations. All of the principal participants understood that state and district policy mandated that state testing student data would bear weight on their standards based evaluation system. None of the participants appeared to be overly concerned about the impact the test scores would have on their performance ratings; nevertheless, they stated that including student data from the yearly tests was inequitable.
Based on the data, a major strength of the district’s evaluation system was that all of the principal participants were able to fully describe their district’s standards based evaluation protocol. Weaknesses included: lack of a comprehensive support system for principals, lack of relationships between supervisors and principals void of interactions and feedback, and the lack of training on the evaluation process and curriculum and instruction. Suggestions for improvement by the participants were centered on professional development, relationships, support, and the alignment of district initiatives to the standards based evaluation system, and work of the school principals
Wilderness rock climbing indicators and climbing management implications in the National Park Service
No full textThis pilot study addresses the need to characterize monitoring indicators for wilderness climbing in the National Park Service (NPS) as which are important to monitoring efforts as components in climbing management programs per Director’s Order #41, Section 7.2 Climbing. This research adopts a utilitarian conceptual framework suited to applied management objectives. Critically, it advances analytical connections between science and management through an integrative review of the resources informing park planning; including law and policy, climbing management documents, academic research on climbing management, recreation ecology, and interagency wilderness character monitoring strategies. Monitoring indicators include biophysical, social, and administrative topics related to climbing and are conceptually structured based on the interagency wilderness character monitoring model. The wilderness climbing indicators require both field and administrative monitoring; field monitoring of the indicators should be implemented by climbing staff and skilled volunteers as part of a patrol program, and administrative indicators mirror administrative wilderness character monitoring methods that can be carried out by a park’s wilderness coordinator or committee. Indicators, monitoring design, and recommended measures were pilot tested in two locations: Grand Canyon and Joshua Tree National Parks. Results indicate that monitoring indicators are: plants; animals; geologic resources; ecological processes; use of motorized equipment; remoteness from sights and sounds of human activity inside wilderness; facilities that decrease self-reliant recreation; management restrictions on visitor behavior; deterioration of loss of integral cultural features; and deterioration of loss of other features of value. This research provides a foundation for monitoring, assessing, and managing wilderness climbing resources in NPS wilderness areas.
Keywords: rock climbing, wilderness, national park, impact, monitoring, indicator, management, plan, change, Joshua Tree, Grand Canyon, recreation