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- Creators: Arizona State University
- Creators: Poulenc, Francis, 1899-1963
Description
This report analyzed the dynamic response of a long, linear elastic concrete bridge subject to spatially varying ground displacements as well as consistent ground displacements. Specifically, the study investigated the bridge’s response to consistent ground displacements at all supports (U-NW), ground displacements with wave passage effects and no soil profile variability (U-WP), and ground displacements with both wave passage effects and soil profile variability (V-WP). Time-history ground displacements were taken from recordings of the Loma Prieta, Duzce, and Chuetsu earthquakes. The two horizontal components of each earthquake time-history displacement record were applied to the bridge supports in the transverse and longitudinal directions. It was found that considering wave passage effects without soil profile variability, as compared with consistent ground displacements, significantly reduced the peak total energy of the system, as well as decreasing the maximum relative longitudinal displacements. The maximum relative transverse displacements were not significantly changed in the same case. It was also found that including both wave passage effects and soil profile variability (V-WP) generally resulted in larger maximum transverse relative displacements, across all earthquake time-histories tested. Similarly, it was found that using consistent ground displacements (U-NW) generally resulted in larger maximum longitudinal relative displacements, as well as larger peak total energy values.
ContributorsSeawright, Jordan Michael (Author) / Hjelmstad, Keith (Thesis advisor) / Rajan, Subramaniam D. (Committee member) / Kavazanjian, Edward (Committee member) / Arizona State University (Publisher)
Created2019
Description
Essential knowledge of Co-continuous composite material properties are explored in this thesis. Mechanical characterization of these materials gives a detailed outlook to use them in design, manufacture and tailor make the products.
Soft and hard polymer materials have extensive properties individually, but when combined to make a single structure, they give an exceptional combination of properties. In this study, Polymer materials used are in the form of Co-Continuous structures (i.e., both soft and hard polymers are continuous throughout the microstructure) fabricated into several microstructures namely, Simple Cubic (SC), Body-Centered Cubic (BCC) and Face Centered Cubic (FCC) shapes. An experimental process is designed and fine-tuned from existing methods to understand and record the mechanical response of these co-continuous polymers. Experimental testing is used to gather detailed information about several constituencies namely stress behavior and damage progression. A 3D imaging technique, Microtomography is used to visualize damage initiation and progression in the sample. Variations in energy absorption, fracture initiation and damage propagation in samples are observed and correlated analysis is performed to provide a logical explanation. Comparative studies are performed as well for different structures.
Based on the Knowledge gained from the above study on co-continuous polymer composites, several conclusions are drawn, and future work directions are suggested.
Soft and hard polymer materials have extensive properties individually, but when combined to make a single structure, they give an exceptional combination of properties. In this study, Polymer materials used are in the form of Co-Continuous structures (i.e., both soft and hard polymers are continuous throughout the microstructure) fabricated into several microstructures namely, Simple Cubic (SC), Body-Centered Cubic (BCC) and Face Centered Cubic (FCC) shapes. An experimental process is designed and fine-tuned from existing methods to understand and record the mechanical response of these co-continuous polymers. Experimental testing is used to gather detailed information about several constituencies namely stress behavior and damage progression. A 3D imaging technique, Microtomography is used to visualize damage initiation and progression in the sample. Variations in energy absorption, fracture initiation and damage propagation in samples are observed and correlated analysis is performed to provide a logical explanation. Comparative studies are performed as well for different structures.
Based on the Knowledge gained from the above study on co-continuous polymer composites, several conclusions are drawn, and future work directions are suggested.
ContributorsVARAKANTHAM, MADHAVA REDDY (Author) / Yongming, Liu (Thesis advisor) / Patel, Jay (Committee member) / Hanqing, Jiang (Committee member) / Arizona State University (Publisher)
Created2019
Description
Social media has become a significant aspect of American life and culture.
Criminal groups including extremists of various ideological milieus have found social
media useful in their recruitment efforts. Further, these online spaces allow extremists to
easily interact with one another, reinforcing each other’s radical perspectives. Little
research has examined social media’s role in radicalization and fewer studies have tested
the differences between the radicalization processes of individuals espousing disparate
ideologies. Using Profiles of Individual Radicalization in the United States, a data set of
804 extremist men, this study sets out to determine whether the role of social media in the
radicalization process varies between Islamist and far right extremists using social
learning as a theoretical framework. The results indicate no significant difference
regarding the role of social media in radicalization between Islamists and far rightists.
Additionally, the odds of having radical friends and family were much lower for Islamists
than far rightists, suggesting only partial support for social learning theory as an
explanation of radicalization.
Criminal groups including extremists of various ideological milieus have found social
media useful in their recruitment efforts. Further, these online spaces allow extremists to
easily interact with one another, reinforcing each other’s radical perspectives. Little
research has examined social media’s role in radicalization and fewer studies have tested
the differences between the radicalization processes of individuals espousing disparate
ideologies. Using Profiles of Individual Radicalization in the United States, a data set of
804 extremist men, this study sets out to determine whether the role of social media in the
radicalization process varies between Islamist and far right extremists using social
learning as a theoretical framework. The results indicate no significant difference
regarding the role of social media in radicalization between Islamists and far rightists.
Additionally, the odds of having radical friends and family were much lower for Islamists
than far rightists, suggesting only partial support for social learning theory as an
explanation of radicalization.
ContributorsStewart, Connor James (Author) / Young, Jacob (Thesis advisor) / Decker, Scott (Committee member) / Telep, Cody (Committee member) / Arizona State University (Publisher)
Created2019
Description
The delivery of construction projects, particularly with respect to design phase or preconstruction efforts, has changed significantly over the past twenty years. As alternative delivery methods such as Construction-Manager-at-Risk (CMAR) and Design-Build models have become more prominent, general contractors, owners, and designers have had the opportunity to take advantage of the collaborative planning opportunities that exist during the preconstruction portion of the project. While much has been written regarding the benefits of more collaborative approaches and the utilization of various tools and practices during preconstruction to mitigate risk and maximize positive outcomes, what is lesser known is how to teach a coursework that exposes students to various tools and practices that are being utilized today. The objective of this research was to create a testable methodology that can be used to analyze a developed approach that answers the question of how to teach preconstruction tools and practices. A coursework was developed and taught as a graduate level class and data was collected from the actual teaching of that class. In addition, feedback was solicited from the construction industry concerning recommended content applicable to such a class. Data was then analyzed to ascertain student retention of the material and topical content of the course. Through these findings and literature review process the methodology and baseline coursework was shown as an effective means to teach preconstruction tools and practices.
ContributorsKutz, Barry Thomas (Author) / Sullivan, Kenneth T. (Thesis advisor) / Standage, Richard (Committee member) / Hurtado, Kristen (Committee member) / Arizona State University (Publisher)
Created2019
Description
Preservice teachers are faced with many challenges as they enter their first year of teaching. This is particularly true when dealing with future-ready skills, such as technology integration in K-12 classrooms, an area where many higher education or teaching faculty may not feel comfortable or fluent enough to support preservice teachers or to model in their own instruction.
This action research study aimed to understand how faculty develop Technological Pedagogical Content Knowledge (TPACK) in ways that will help them to enhance their instruction and model technology integration for preservice teachers. An online community was created that allowed teacher educators to interact synchronously or asynchronously to collaborate, learn, and practice new technological skills. This community served as a place for teacher educators to play with new technology and to share their ideas and practices with their peers—ideally to begin the process of developing the knowledge and fluency with technology that would allow them to better support teacher education students.
Both qualitative and quantitative data were used to explore faculty’s development of TPACK. A pre-survey, retrospective pre-survey, and post-survey were administered and analyzed. Also, interviews of participants and observations of the online community were used to collect qualitative data.
The results of the study showed an increase in participants’ confidence for selecting technologies to enhance their instruction after they participated in the online community. Also, the participants felt more confident using strategies that combine content, technologies, and teaching approaches in their classrooms or other learning environments.
In Chapter 5, a discussion of the findings was presented, in which several main implications are shared for researchers who might be engaged in similar work. Also, the lessons learned from this action research are explained, as well as the limitations experienced in this study.
This action research study aimed to understand how faculty develop Technological Pedagogical Content Knowledge (TPACK) in ways that will help them to enhance their instruction and model technology integration for preservice teachers. An online community was created that allowed teacher educators to interact synchronously or asynchronously to collaborate, learn, and practice new technological skills. This community served as a place for teacher educators to play with new technology and to share their ideas and practices with their peers—ideally to begin the process of developing the knowledge and fluency with technology that would allow them to better support teacher education students.
Both qualitative and quantitative data were used to explore faculty’s development of TPACK. A pre-survey, retrospective pre-survey, and post-survey were administered and analyzed. Also, interviews of participants and observations of the online community were used to collect qualitative data.
The results of the study showed an increase in participants’ confidence for selecting technologies to enhance their instruction after they participated in the online community. Also, the participants felt more confident using strategies that combine content, technologies, and teaching approaches in their classrooms or other learning environments.
In Chapter 5, a discussion of the findings was presented, in which several main implications are shared for researchers who might be engaged in similar work. Also, the lessons learned from this action research are explained, as well as the limitations experienced in this study.
ContributorsScott, Lynda (Author) / Henriksen, Danah (Thesis advisor) / Mishra, Punya (Committee member) / Wolf, Leigh (Committee member) / Leahy, Sean (Committee member) / Arizona State University (Publisher)
Created2019
Description
Environmental hazards and disaster researchers have demonstrated strong associations between sociodemographic indicators, such as age and socio-economic status (SES), and hazard exposures and health outcomes for individuals and in certain communities. At the same time, behavioral health and risk communications research has examined how individual psychology influences adaptive strategies and behaviors in the face of hazards. However, at present, we do not understand the explanatory mechanisms that explain relationships between larger scale social structure, individual psychology, and specific behaviors that may attenuate or amplify risk. Extreme heat presents growing risks in a rapidly warming and urbanizing world. This dissertation examines the social and behavioral mechanisms that may explain inequitable health outcomes from exposure to concurrent extreme heat and electrical power failure in Phoenix, AZ and extreme heat in Detroit, MI. Exploratory analysis of 163 surveys in Phoenix, AZ showed that age, gender, and respondent’s racialized group identity did not relate to thermal discomfort and self-reported heat illness, which were only predicted by SES (StdB = -0.52, p < 0.01). Of the explanatory mechanisms tested in the study, only relative air conditioning intensity and thermal discomfort explained self-reported heat illness. Thermal discomfort was tested as both a mechanism and outcome measure. Content analysis of 40 semi-structured interviews in Phoenix, AZ revealed that social vulnerability was associated with an increase in perceived hazard severity (StdB = 0.44, p < 0.01), a decrease in perceived adaptation efficacy (StdB = -0.38, p = 0.02), and an indirect increase (through adaptive efficacy) in maladaptive intentions (StdB = 0.18, p = 0.01). Structural equation modeling of 244 surveys in Phoenix, AZ and Detroit, MI revealed that relationships between previous heat illness experience, perceived heat risk, and adaptive intentions were significantly moderated by adaptive capacity: high adaptive capacity households were more likely to undertake adaptive behaviors, and those decisions were more heavily influenced by risk perceptions and previous experiences. However, high adaptive capacity households had lower risk perceptions and fewer heat illness experiences than low adaptive capacity households. A better understanding of the mechanisms that produce social vulnerability can facilitate more salient risk messaging and more targeted public health interventions. For example, public health risk messaging that provides information on the efficacy of specific adaptations may be more likely to motivate self-protective action, and ultimately protect populations.
ContributorsChakalian, Paul Michael (Author) / Harlan, Sharon L (Thesis advisor) / Hondula, David M. (Thesis advisor) / White, Dave D (Committee member) / Arizona State University (Publisher)
Created2019
Description
One of the single-most insightful, and visionary talks of the 20th century, “There’s plenty of room at the bottom,” by Dr. Richard Feynman, represented a first foray into the micro- and nano-worlds of biology and chemistry with the intention of direct manipulation of their individual components. Even so, for decades there has existed a gulf between the bottom-up molecular worlds of biology and chemistry, and the top-down world of nanofabrication. Creating single molecule nanoarrays at the limit of diffraction could incentivize a paradigm shift for experimental assays. However, such arrays have been nearly impossible to fabricate since current nanofabrication tools lack the resolution required for precise single-molecule spatial manipulation. What if there existed a molecule which could act as a bridge between these top-down and bottom-up worlds?
At ~100-nm, a DNA origami macromolecule represents one such bridge, acting as a breadboard for the decoration of single molecules with 3-5 nm resolution. It relies on the programmed self-assembly of a long, scaffold strand into arbitrary 2D or 3D structures guided via approximately two hundred, short, staple strands. Once synthesized, this nanostructure falls in the spatial manipulation regime of a nanofabrication tool such as electron-beam lithography (EBL), facilitating its high efficiency immobilization in predetermined binding sites on an experimentally relevant substrate. This placement technology, however, is expensive and requires specialized training, thereby limiting accessibility.
The work described here introduces a method for bench-top, cleanroom/lithography-free, DNA origami placement in meso-to-macro-scale grids using tunable colloidal nanosphere masks, and organosilane-based surface chemistry modification. Bench-top DNA origami placement is the first demonstration of its kind which facilitates precision placement of single molecules with high efficiency in diffraction-limited sites at a cost of $1/chip. The comprehensive characterization of this technique, and its application as a robust platform for high-throughput biophysics and digital counting of biomarkers through enzyme-free amplification are elucidated here. Furthermore, this technique can serve as a template for the bottom-up fabrication of invaluable biophysical tools such as zero mode waveguides, making them significantly cheaper and more accessible to the scientific community. This platform has the potential to democratize high-throughput single molecule experiments in laboratories worldwide.
At ~100-nm, a DNA origami macromolecule represents one such bridge, acting as a breadboard for the decoration of single molecules with 3-5 nm resolution. It relies on the programmed self-assembly of a long, scaffold strand into arbitrary 2D or 3D structures guided via approximately two hundred, short, staple strands. Once synthesized, this nanostructure falls in the spatial manipulation regime of a nanofabrication tool such as electron-beam lithography (EBL), facilitating its high efficiency immobilization in predetermined binding sites on an experimentally relevant substrate. This placement technology, however, is expensive and requires specialized training, thereby limiting accessibility.
The work described here introduces a method for bench-top, cleanroom/lithography-free, DNA origami placement in meso-to-macro-scale grids using tunable colloidal nanosphere masks, and organosilane-based surface chemistry modification. Bench-top DNA origami placement is the first demonstration of its kind which facilitates precision placement of single molecules with high efficiency in diffraction-limited sites at a cost of $1/chip. The comprehensive characterization of this technique, and its application as a robust platform for high-throughput biophysics and digital counting of biomarkers through enzyme-free amplification are elucidated here. Furthermore, this technique can serve as a template for the bottom-up fabrication of invaluable biophysical tools such as zero mode waveguides, making them significantly cheaper and more accessible to the scientific community. This platform has the potential to democratize high-throughput single molecule experiments in laboratories worldwide.
ContributorsShetty, Rishabh Manoj (Author) / Hariadi, Rizal F (Thesis advisor) / Gopinath, Ashwin (Committee member) / Varsani, Arvind (Committee member) / Nikkhah, Mehdi (Committee member) / Tillery, Stephen H (Committee member) / Hu, Ye (Committee member) / Arizona State University (Publisher)
Created2019
Description
Glioblastoma (GBM) is a highly invasive and deadly late stage tumor that develops from abnormal astrocytes in the brain. With few improvements in treatment over many decades, median patient survival is only 15 months and the 5-year survival rate hovers at 6%. Numerous challenges are encountered in the development of treatments for GBM. The blood-brain barrier (BBB) serves as a primary obstacle due to its innate ability to prevent unwanted molecules, such as most chemotherapeutics, from entering the brain tissue and reaching malignant cells. The GBM cells themselves serve as a second obstacle, having a high level of genetic and phenotypic heterogeneity. This characteristic improves the probability of a population of cells to have resistance to treatment, which ensures the survival of the tumor. Here, the development and testing of two different modes of therapy for treating GBM is described. These therapeutics were enhanced by pathogenic peptides known to improve entry into brain tissue or to bind GBM cells to overcome the BBB and/or tumor cell heterogeneity. The first therapeutic utilizes a small peptide, RVG-29, derived from the rabies virus glycoprotein to improve brain-specific delivery of nanoparticles encapsulated with a small molecule payload. RVG-29-targeted nanoparticles were observed to reach the brain of healthy mice in higher concentrations 2 hours following intravenous injection compared to control particles. However, targeted camptothecin-loaded nanoparticles were not capable of producing significant treatment benefits compared to non-targeted particles in an orthotopic mouse model of GBM. Peptide degradation following injection was shown to be a likely cause for reduced treatment benefit. The second therapeutic utilizes chlorotoxin, a non-toxic 36-amino acid peptide found in the venom of the deathstalker scorpion, expressed as a fusion to antibody fragments to enhance T cell recognition and killing of GBM. This candidate biologic, known as anti-CD3/chlorotoxin (ACDClx) is expressed as an insoluble protein in Nicotiana benthamiana and Escherichia coli and must be purified in denaturing and reducing conditions prior to being refolded. ACDClx was shown to selectively activate T cells only in the presence of GBM cells, providing evidence that further preclinical development of ACDClx as a GBM immunotherapy is warranted.
ContributorsCook, Rebecca Leanne (Author) / Blattman, Joseph N (Thesis advisor) / Sirianni, Rachael W. (Thesis advisor) / Mor, Tsafrir (Committee member) / Anderson, Karen (Committee member) / Arizona State University (Publisher)
Created2019
Description
Reliable and secure operation of bulk power transmission system components is an important aspect of electric power engineering. Component failures in a transmission network can lead to serious consequences and impact system reliability. The operational health of the transmission assets plays a crucial role in determining the reliability of an electric grid. To achieve this goal, scheduled maintenance of bulk power system components is an important activity to secure the transmission system against unanticipated events. This thesis identifies critical transmission elements in a 500 kV transmission network utilizing a ranking strategy.
The impact of the failure of transmission assets operated by a major utility company in the Southwest United States on its power system network is studied. A methodology is used to quantify the impact and subsequently rank transmission assets in decreasing order of their criticality. The analysis is carried out on the power system network using a node breaker model and steady state analysis. The light load case of spring 2019, peak load case of summer 2023 and two intermediate load cases have been considered for the ranking. The contingency simulations and power flow studies have been carried out using a commercial power flow study software package, Positive Sequence Load Flow (PSLF). The results obtained from PSLF are analyzed using Matlab to obtain the desired ranking. The ranked list of transmission assets will enable asset managers to identify the assets that have the most significant impact on the overall power system network performance. Therefore, investment and maintenance decisions can be made effectively. A conclusion along with a recommendation for future work is also provided in the thesis.
The impact of the failure of transmission assets operated by a major utility company in the Southwest United States on its power system network is studied. A methodology is used to quantify the impact and subsequently rank transmission assets in decreasing order of their criticality. The analysis is carried out on the power system network using a node breaker model and steady state analysis. The light load case of spring 2019, peak load case of summer 2023 and two intermediate load cases have been considered for the ranking. The contingency simulations and power flow studies have been carried out using a commercial power flow study software package, Positive Sequence Load Flow (PSLF). The results obtained from PSLF are analyzed using Matlab to obtain the desired ranking. The ranked list of transmission assets will enable asset managers to identify the assets that have the most significant impact on the overall power system network performance. Therefore, investment and maintenance decisions can be made effectively. A conclusion along with a recommendation for future work is also provided in the thesis.
ContributorsBhandari, Harsh Nandlal (Author) / Vittal, Vijay (Thesis advisor) / Heydt, Gerald T (Thesis advisor) / Ayyanar, Raja (Committee member) / Arizona State University (Publisher)
Created2019
Description
In the last few decades, with the revolution of availability of low-cost microelectronics, which allow fast and complex computations to be performed on board, there has been increasing attention to aerial vehicles, especially rotary-wing vehicles. This is because of their ability to vertically takeoff and land (VTOL), which make them appropriate for urban environments where no runways are needed. Quadrotors took considerable attention in research and development due to their symmetric body, which makes them simpler to model and control compared to other configurations.
One contribution of this work is the design of a new open-source based Quadrotor platform for research. This platform is compatible with both HTC Vive Tracking System (HVTS) and OptiTrack Motion Capture System, Robot Operating System (ROS), and MAVLINK communication protocol.
The thesis examined both nonlinear and linear modeling of a 6-DOF rigid-body quadrotor's dynamics along with actuator dynamics. Nonlinear/linear models are used to develop control laws for both low-level and high-level hierarchical control structures. Both HVTS and OptiTrack were used to demonstrate path following for single and multiple quadrotors. Hardware and simulation data are compared. In short, this work establishes a foundation for future work on formation flight of multi-quadrotor.
One contribution of this work is the design of a new open-source based Quadrotor platform for research. This platform is compatible with both HTC Vive Tracking System (HVTS) and OptiTrack Motion Capture System, Robot Operating System (ROS), and MAVLINK communication protocol.
The thesis examined both nonlinear and linear modeling of a 6-DOF rigid-body quadrotor's dynamics along with actuator dynamics. Nonlinear/linear models are used to develop control laws for both low-level and high-level hierarchical control structures. Both HVTS and OptiTrack were used to demonstrate path following for single and multiple quadrotors. Hardware and simulation data are compared. In short, this work establishes a foundation for future work on formation flight of multi-quadrotor.
ContributorsAltawaitan, Abdullah (Author) / Rodriguez, Armando A (Thesis advisor) / Tsakalis, Konstantinos (Committee member) / Berman, Spring (Committee member) / Arizona State University (Publisher)
Created2019