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Riesz Transforms on a Sphere
No full textMotivated by the Navier-Stokes equations, which are a set of unsolved equations related to fluid motion in R^3, we explored the incompressibility condition and the Neumann boundary problem. After exploring, we noticed that using iterated Riesz transforms of the boundary data could be used to get information about the velocity field directly from the boundary data. We then used this same logic to look at the same problem in a spherical space, and found no definition for the Riesz transforms. By using the incompressibility condition and solving the Neumann boundary problem on a sphere, using both separation of variables and potential theory, we can define the Riesz transforms of a function on the sphere. This allows us to use boundary data on a sphere to describe the divergence-free field, or in the case of the incompressible Navier-Stokes equation, allows us to solve for the velocity field given initial data
Transformation of Western Hemlock Tree Crowns by Dwarf Mistletoe
Get PDFHemlock dwarf mistletoe (Arceuthobium tsugense subsp. tsugense) is an arboreal, hemiparasitic plant that principally parasitizes western hemlock (Tsuga heterophylla). Hemlock dwarf mistletoe exerts a profound influence on infected trees that can drastically change the structure of the tree crown due to reduced growth, top dieback, branch deformation and death, resulting in unique habitat structures, changed fire dynamics, and more severe drought impacts. Although dwarf mistletoe is important to tree crowns, most research has been from the ground or by felling trees. In this study, we climbed 16 western hemlock trees (age 97 – 321 years) across a gradient of infection (0 – 100% of branches infected) and measured occurrence of all dwarf mistletoe infections, branch and crown architecture, and dwarf mistletoe caused deformities. Sapwood area was measured at the top of buttressing or 1.37 m above the ground (f-diameter) and at base of live crown. To explore the impacts of increasing infection severity, over 25 different response variables were examined using linear and generalized linear models to estimate mean responses among the 16 western hemlocks. We developed three metrics of
severity as explanatory variables for the models: total infection incidence, proportion of all live branches infected, and proportion of all live, infected branches with 33 percent or more foliage distal to infection. Many effects of dwarf mistletoe on crown structure appear subtle, except for deformations. Increasing severity led to crowns experiencing an apparent compaction, where crown volume was reduced while deformity volume increased, and crown volumes became increasingly comprised of deformities. A strong effect of dwarf mistletoe intensification is the reduction of branch foliage and an increase in the proportional amount of foliage distal to infections, and therefore a likely reduction in carbohydrates available to tree growth. Sapwood areas at f-diameter and at base of live crown were unrelated to all metrics of infection severity. Branch length and diameters were also unaffected by increasing infection severity despite heavily infected branches supporting 1 to 70 infections. This suggests infected trees compensate for the water and nutrient loss through changes to the crown architecture such as reduced foliage instead of through conductive tissues. Our results suggest shifts in crown structure reflect a shift in function, from prioritizing biomass production and growth, to tree survival
Building Resilient Oregon Coastal Communities: Reimagining Critical Facilities through Latinx Sense of Place
Get PDFThis paper examines equitability of critical facilities within resilience planning efforts and how it relates to accessibility and utilization for Latinx community members along the Oregon coast in relation to natural hazards including the Cascadia Subduction Zone. Interviews and focus groups were conducted with emergency management personnel and Latinx coastal community members in Newport City and Clatsop County regarding their perceptions of critical facility values and locations, in order to create an inclusive sense of place. The interviews and focus groups were analyzed and used to identify necessary changes within resilience planning efforts that will improve resilience levels for Latinx community members along the Oregon coast. This research finds that current resilience planning focus and efforts regarding critical facilities are not meeting the needs of Oregon Latinx coastal community members, creating inequitable access and utilization in times of need. This paper identifies Latinx determined critical facilities and their associated values resulting in various suggested improvements for equitable accessibility and utilization. This research is meant to expose systemic issues in resilience planning efforts regarding critical facilities, not to catalog cultural differences. A critical facility according to FEMA, provides services and functions essential to a community, especially during and after a disaster (FEMA, n.d.)
Understanding the similarities and differences between academia and the engineering workplace through barriers to adoption, epistemic beliefs, and problem-solving behavior
Get PDFEngineering education research has led to a greater understanding of the gap in preparedness of students for the engineering industry. Multiple studies comparing the workplace and academic contexts and the participants in those contexts (i.e., students, faculty, and engineering practitioners) have emphasized similarities and differences between the two contexts by examining the material presented and the problem-solving behaviors of the participants of each context. The purpose of this study is to explore this gap further by working closely and collaboratively with engineering practitioners and faculty as they iteratively develop authentic design activities and rubrics for civil engineering courses. The development of these learning tools acted as a mediating task to understand more about the epistemic beliefs of engineering practitioners and faculty as is relates to engineering knowledge and barriers to adoption. A thematic analysis relying on a robust data set of multiple semi-structured interviews led to the emergence of in-vivo codes and themes that compare the two contexts. Findings from this exploration noted that the meaning of an answer is defined differently by engineering practitioners and faculty. Engineering practitioners tend to focus more on the solution process and why decisions are made where faculty focus more on the final answer and how the knowledge gained through solving a problem leads to conceptual understanding. Multiple themes emerged and were mapped across the three overriding concerns and five dimensions of epistemic beliefs that led to inherent similarities and differences between the engineering practitioners and faculty. Results indicate that both engineering practitioners and faculty believe that where knowledge is located, and the source of knowledge are related to practical, real-world experiences. Differences in epistemic beliefs show that faculty emphasize the abstract learning and confidence of their students in their classroom. This contrasts with how engineering practitioners’ beliefs emphasis the consequences of their designs in the workplace. This study also found that barriers to adoption such as time, incentives, and complexity of the design activities prevent adoption of new innovations in engineering courses. While the design activities developed in this study have been accepted by the faculty for testing in their courses, more research is needed to determine if they can be fully adopted and how the iterative process can be improved for future adoption efforts. Lastly, the problem-solving behaviors and heuristics of engineering practitioners and students as they solve engineering problems with multiple solution pathways has highlighted differences in their allocation of time and approaches to problem solving. These findings offer additional understanding of the differences and similarities between the two contexts and help to understand the gap in preparedness of students for the engineering industry. Results from this study should be used to help assist in the development of new learning innovations. If the goal of engineering education is to prepare students for the engineering industry, educators should have access to the tools necessary to do so that are informed by the experts who use them
A Methodological Approach for Structural Health Monitoring of Mass-Timber Buildings Under Construction
Get PDFAs mass-timber building construction rises around the globe, there exists the need to verify the long-term, in-situ behavior and performance of these structural systems. Structural health monitoring (SHM), generally defined as a damage detection strategy consisting of a network of sensors, a data acquisition system, and algorithms for data analysis, can be implemented for this scope. However, there are no clear guidelines or standards for implementing timber or mass-timber SHM programs. Although guidelines exist for SHM of other building material types, they do not address some key considerations for timber monitoring. As wood is a natural, hygroscopic material, it absorbs and releases moisture from or into the surrounding air, changing the moisture content of the wood. As the moisture content changes, so do many of the physical and mechanical properties of the material. Therefore, to understand the structural performance of timber and mass-timber buildings, quantifying the hygrothermal performance is critical. The lack of standards however leaves ambiguities associated with sampling criteria for timber monitoring, how to clean and analyze data, and how to account for hygrothermal behavior in damage detection algorithms. It has also been attributed to the limited number of timber SHM programs as well as the reason these programs often cannot be compared with one another.
To move towards standardization of SHM for timber and mass-timber buildings, this project focused on the development of a methodological approach for monitoring these buildings during construction. The approach intends to simplify the necessary steps associated with implementing SHM into these buildings during the construction phase, address methods of pre-processing and cleaning data, and develop tools for data analysis and visualization. The construction phase was specifically considered as this phase can provide valuable insight into environmental and mechanical loads experienced during construction as well as insight into construction procedures and performance of them. However, implementing an SHM program during construction has additional challenges compared to in-service monitoring, for example using only temporary power supply to collect data, coordination with building stakeholders, and uncontrolled environmental conditions that may affect data. The approach was to be validated through the implementation of an SHM program in a mass-timber building under construction. To be validated, the approach must provide data that could be used by the industry to document construction performance. The study was accomplished in two steps: (i) literature review, surveys, and design development of an SHM plan for a real building, and (ii) the proposal of a methodological approach with validation in a mass-timber building through analysis and use of data to provide insight into the construction performance of the building.
The first phase of this project focused on a literature review and survey of researchers in the mass-timber monitoring field. The results of both were used to gather necessary background information related to monitoring programs, specificities for mass-timber monitoring, phenomena of interest, sensor limitations, and common sensors used. Further consideration included identification of project objectives, sampling criteria, budget, architectural constraints, phasing of sensor installation, limitations of monitoring equipment, and a long-term plan for data acquisition, storage, and analysis. The outcome of this phase was that the state-of-the-art for timber and mass-timber SHM did not exist and guidelines were not available. For this reason, there have been inconsistencies in monitoring programs, repeated errors among projects, and even failed monitoring projects. Therefore, the development and validation of a methodological approach must attempt to piece together best practices, state-of-the-arts from various subsections of monitoring, and compile lessons learned to adequately develop a benchmark to implement SHM of mass-timber buildings under construction.
The second phase of this project was the development of the methodological approach for mass-timber building monitoring under construction. The procedure was validated using SHM data from the George Peavy Forest Science Complex, or “Peavy Hall,” a mass-timber building at Oregon State University. The building was monitored for its hygrothermal and static performance over the last ten months of construction. The measurands of interest were tension loss in post-tensioned self-centering cross-laminated timber (CLT) shear walls, displacements, rotations, and movements of cross-laminated timber shear walls, moisture content of CLT panels and slabs, glulam beams and columns, and mass plywood panel (MPP) roof slabs, heat transfer in CLT panels, and indoor and outdoor environmental conditions, including relative humidity, temperature, precipitation amounts, as well as wind speeds, directions, and gusts. A significant step in this approach involved data cleaning, visualization, and analysis, which were implemented into data platforms for locations of interest throughout the building. The data platforms were implemented using opensource programs such that minor modifications can be made for use on previous or future projects to compare data and processing techniques.
Outcomes of the methodological approach included documentation of construction performance as it relates to the post-tensioned self-centering shear walls, and the moisture performance of the CLT and MPP roof slabs. Thus, the methodology was considered to be validated. The approach will be further developed and refined for in-service monitoring with continued validation in the studied case. Lastly, specific datasets will be used for model verification, further testing and analysis, development of digital twins, and other future research purposes.
Strength in Numbers: How Multivalent WW-PPXY Interactions Regulate Cell Signaling
Get PDFCell signaling is often mediated by protein-protein interactions, which must be specific, tunable, and transient to allow agile responsiveness to cellular messages. Due to their unique properties, multivalent, intrinsically disordered proteins make ideal candidates to accomplish these vital tasks. A single protein with multiple binding sites may bind numerous partners, leading to diverse but integrated cellular outcomes. However, despite their high prevalence and importance, several challenges have hindered the detailed characterization of multivalent, disordered proteins and complexes. First, these proteins are often low yielding and have poor stability and solubility. Second, the inherent dynamic nature of multivalent, disordered proteins often translates to the formation of intricate heterogenous mixtures of protein complexes. Third, few biophysical techniques are amenable to studying these complicated and dynamic systems.
In this work, we overcome these challenges to elucidate the mechanisms of complex assembly for three sets of interactions. The defining feature of each interaction is multivalency, as each protein contains multiple recognition sites. At the heart of these interactions is the multivalent scaffolding protein, Angiomotin-Like 1 (AMOTL1), which plays essential roles in cell growth regulation, cell polarity, shape, and tight junction formation. Important for this thesis is a largely disordered segment of AMOTL1 with three short linear motifs of the sequence L/PPXY (L=leucine, P=proline, Y=tyrosine, and X=any amino acid, hereafter referred to as PPXY). The partner proteins – YES-associated protein (YAP), Kidney and Brain-expressed protein (KIBRA), and neural precursor cell-expressed developmentally downregulated 4 (NEDD4) – contain multiple repeats of the globular WW domain, an arrangement that facilitates multivalent interactions with AMOTL1 that are functionally relevant. Thus, understanding how each protein complex assembles in the context of multivalency and how AMOTL1 discriminates between its partners could inform critical cellular processes.
Chapter 1 introduces unique features that make intrinsically disordered proteins ideal candidates in multivalent interactions. Emphasis is placed on specific multivalent interactions mediated by the largely disordered PPXY-motif region of AMOTL1 and its multivalent globular WW domain-containing partners. In the following chapters, we provide in-depth molecular biophysics studies of the solution properties of the disordered PPXY-rich segment of AMOTL1 and its interaction with YAP (Chapter 2), KIBRA (Chapter 3) and NEDD4 (chapter 5). Unique characteristics of each interaction are highlighted. Chapter 4 is a study of the solution properties of the multiple WW domains of NEDD4, with emphasis on structural dynamics and global communication between the domains. Chapter 6 summarizes key findings, impact, and future directions of this work
Field-Free Precessional Magnetization Switching by Focused Surface Acoustic Waves
Get PDFIn this research, the possibility of the precessional magnetization switching by focused surface acoustic waves, without external magnetic field, has been demonstrated. The technique of generating an effective magnetic field by applying stress to a magnetostrictive material via a surface acoustic wave is applied to perform field-free magnetization switching. It is shown that focused interdigital transducers can provide sufficient surface acoustic wave amplitude to achieve switching. For the purpose of controlling the timing and direction of acoustic waves, this research proposes a device containing two perpendicular channels of the interdigital transducers making ±45° angles with the initial magnetization direction of a ferromagnetic thin film at the focal point of the focused interdigital transducers. At first, one of the interdigital transducer channels is excited to generate surface acoustic waves, which will change the magnetization direction in the magnetostrictive material as a consequence of the Villari effect, in combination with precessional magnetization dynamics. Next, the other channel is excited when the magnetization is furthest away from its initial position. This second surface acoustic wave will finalize the magnetization reversal, and thus, field-free switching can be accomplished. To perform the magnetization switching, a high strain amplitude in the magnetostrictive material is required and hence surface acoustic wave focused interdigital transducers are necessary.
Focused interdigital transducers are design for Y-cut lithium niobate substrate. Due to the crystalline structure of Y-cut lithium niobate, the surface acoustic wave velocity in this material depends on propagation direction. To design focused interdigital transducers that will generate maximum strain amplitude in the magnetostrictive material, the difference between phase velocity and group velocity, as well as the power flow angle, of the acoustic wave on this crystalline structure must be considered. The research design of a surface acoustic wave focused interdigital transducer device has been experimentally verified by laser interferometry. The surface acoustic wave is focused with 400 pm vibrational amplitude at the focal point. Finally, the magnetization dynamics with the experimental strain value has been simulated to demonstrate the possibility of the field-free magnetization switching
Understanding Supervisors Experience of Conducting Supervision to Home-Based Counselors: Two IPA Studies on the Experience of Supervisors of Home-Based Counselors
No full textHome-based counseling (HBC) occurs when counselors provide therapy services to individuals and families within the clients’ home environment. Since its inception in the 1980s, HBC has become a common practice within the counseling field. In 2014, the U.S. Bureau of Labor Statistics (2014) named HBC one of the fastest-growing divisions of mental health services. However, a gap in research exists regarding this widely used form of counseling. Currently, only a small number of articles provide home-based counseling practice considerations, conceptual content, and the experience of HBCs. However, a lack of research directly addresses supervisors' experiences providing supervision to home-based counselors. Using Interpretative Phenomenological Analysis (IPA) qualitative methods, this dissertation sought to understand the experiences of supervisors who provide supervision to home-based counselors.
The research approach for both studies is Interpretative Phenomenological Analysis
(IPA). IPA allows the researcher to explore how individuals make meaning of their experiences. The researcher recruited seven participants from across the United States. Participants for this study met the criteria of being independently licensed as professional counselors in their state of practice. They have currently or within two years of the study have provided supervision in their professional role to home-based counselors. The researcher utilized IPA data analysis as described by Smith et al. (2008). Strategies to increase trustworthiness in both studies included peer debriefing, reflexivity, thick description, and member checks.
The first study (n=7) explored the lived experiences of supervisors of HBCs. The study’s findings indicate that supervisors of HBCs experience: a sense of marginalization within the counseling profession, navigating the chaos of the home-based environment, learning by drawing upon positive and negative experiences from their past, and feeling empowered or disempowered by agency expectations and level of agency support.
The second study (n=7) explored how participants experience their training in the backdrop of providing supervision to HBCs. The study’s findings indicate that supervisors of HBCs experience: feeling a sense of disillusionment connected to training, the dissonance between training’s valuing of intersectionality and application in the complex HBC setting, multigenerational on-the-job training, and a sense of constant adaptation to meet the insufficiency of training.
Implications for this research are directed toward foundational knowledge and support of supervisors of HBCs. The findings emphasize the nuances, challenges, and lack of support these supervisors experience. Therefore, implications are geared toward supervision practice, training, counselor educators, and the profession of counseling
The Symbioses of Oblivious Random Access Memory and Trusted Execution Environments
Get PDFIn recent years, Oblivious Random Access Memory (ORAM) controllers in Trusted Execution Environments (TEEs) have become a popular area of investigation, as coresident trusted systems allow for significantly more efficient oblivious execution. Further, in the case of Intel architectures, oblivious execution effectively eliminates the majority of confidentiality leakage holes in SGX. Unfortunately, the state of the art TEE-ORAM memory solutions for Intel SGX are still considered too slow for most applications, with memory block requests being handled at milliseconds latency. PRORAM, our novel oblivious memory controller, can deliver a block in the order of microseconds, approximately 10x–40x faster than prior work. This analysis will describe the design and implementation techniques that led to our significant performance gains
Effect of Genotype and Environment on Organic Winter and Spring Naked Barley Composition and Food Functionality
Get PDFNaked barley is a rich source of fiber and phytonutrients but is not widely consumed by humans. The author contends that increasing population-wide consumption of wholegrain naked-barley would accrue a net positive public health benefit by helping to increase total fiber and phytonutrient consumption. Many of the leading causes of morbidity and mortality can be prevented by adequate fiber consumption. However, for barley there are impediments to its uptake as a food. For example, the incompleteness of the body of knowledge about genetic and environmental effects on composition and functionality. Another impediment is the lack of a uniform or standardized way of classifying food barley beyond the covered/naked, two row/six row, and pearled/not pearled dichotomies. A standardized classification system using a manageable number of accessible quality traits would benefit both breeders and processors.
Chapter 3 investigated the impacts of genetics and environment on composition and functionality of organic winter and facultative naked barleys, identified the minimum number of traits that may categorize their functionality, and determined the effects of planting facultative genotypes in either fall or spring. Organic winter naked barleys grown in two locations across three years were assessed using a total of ten food traits, which, for ease of discussion were divided into pre-cooking (kernel hardness, protein and beta-glucan contents, flour water absorption and batter flow) and cooking traits (three RVA pasting parameters, and cooked grain yield and hardness). Hypothesis one: genotype, environment, and their interactions all significantly influence naked barley composition and functionality. Hypothesis one was supported by our findings. Importantly for the breeding enterprise, genotype had a statistically significant influence on all ten traits. Nonetheless, there were traits where environmental effects dominated (hardness, protein, flour water absorption and batter flow, RVA peak and breakdown, and cooked grain texture). Hypothesis two: a manageable number of traits will effectively characterize overall food barley functionality. Principal component analysis (PCA) identified six traits (protein and beta-glucan contents, flour water absorption and batter flow, RVA peak time, and cooked grain texture) that accounted for 79% of data variance across principal components (PCs) 1 and 2. This finding supported hypothesis two. Furthermore, clustering associated with starch type (waxy vs non-waxy) was observed in the plane of PCs 1 and 2. Hypothesis three: planting facultative genotypes in either spring or fall would alter their composition and functionality. These preliminary findings support this by demonstrating that spring planting was associated with higher protein and beta-glucan contents, higher flour water absorption, shorter batter flows, and higher RVA peak and breakdown viscosities. Whether this finding is more broadly applicable requires further investigation.
Chapter 4 investigated the same factors as in Chapter 3, this time using spring genotypes. Sixteen genotypes (16-genotype study) were grown at four locations across three years and assessed using only 5 traits as a result of limited grain quantities. A subset of 10 of the 16 genotypes plus one other (11-genotype study) were grown at one location across two years. These samples had sufficient grain to be assessed using all ten traits itemized above. Hypothesis one from Chapter 3 was also applied to these samples. Evidence from both the 16- and 11-genotype studies supported the hypothesis. Again, genotype had a significant influence on all ten food traits but was not always dominant. This finding strengthens the argument that breeders have genetic leverage to improve the studied barley functionality traits. Preharvest sprouting (PHS) was a challenge, particularly in the 16-genotype, four-location study. This study demonstrated a need to breed PHS resistance into naked barley and, in the absence of inherent resistance, to select growing locations not prone to harvest rains. In the 11-genotype, one-location study, genotype was a more dominant influence on the functionality traits, even after accounting for the effect of “year”. Hypothesis two from Chapter 3 was reprised here and modified to assert that the same traits will effectively characterize spring barleys. We did find that the same traits identified via PCA in winter barley were applicable to these spring barleys. In this case the traits accounted for 82% of the variance across PCs 1 and 2. Consistent identification of the same traits in independent winter and spring studys suggests that these traits are robust descriptors of barley functionality for food and therefore may serve as standard traits for categorizing food barley.
This thesis has validated previous work on genetics and environmental effects on barley composition, expanded on naked barley food quality by assessing new traits, identified key traits with practical value for breeders and processors, contributed to improving the classification system of food barley, and identified needs for breeding PHS resistance and for measuring protein in colored genotypes