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Enhanced Measurement of Transmission with Quantum States of Light
Get PDFQuantum metrology is the application of quantum mechanics towards the enhancement of
measurements. This is typically achieved through either quantum measurements, such as
photon counting, or using quantum states. In this thesis, we focus on the use of a high
power quantum state of light, known as the bright two mode squeezed state, to achieve
a quantum enhancement in the estimation of transmission by reducing the uncertainty in
the value down to the fundamental limit allowed by quantum mechanics. These bright two
mode squeezed states are of particular use to enhance the precision of many sensing devices
beyond the classical limit, via quantum enhancement, and current state-of-the-art due to
being generated at high power.
We start with an introduction to the theoretical calculations that set the fundamental
lower limit in the uncertainty in the estimation of a parameter, transmission in our case. This
limit is given by the quantum Cramér-Rao bound. We go over the bound for the bright single
mode squeezed state and calculate the bound for the bright two mode squeezed state. These
squeezed states offer a large enhancement in transmission estimation at high transmissions
compared to classical states. We also expand on these bound to include losses in the states
both before and after probing the transmissive system and detail measurements that are
able to saturate the quantum Cramér-Rao bound, even in the presence of loss. Operating at
this bound means that, for our state, no other estimation can do better.
We experimentally verify that we can estimate transmission at the quantum Cramér-
Rao bound for the bright two mode squeezed state. Achieving such uncertainty levels at
the quantum Cramér-Rao bound required extensive control of our experiment and precise
calibration of our state and system. In addition, we expand upon the calculations of the
quantum Cramér-Rao bound to include generation of the bright two mode squeezed state in
a more realistic system that takes into account the absorptive medium that is used.
Finally, we examine systems that have a resonant frequency dependent transmission and
phase responses. This allows us to compare and identify the optimal measurement parameter for use in estimating frequency shifts in the system response. We focus on systems
with resonance responses, in which there is a large change in transmission around a single
frequency. We show that for resonances with the common Lorentzian lineshape, the phase
measurement is in general more sensitive to frequency shifts than the transmission measurements. However, for lineshapes with a sharper change in transmission, we show that the
transmission measurement can do better than phase measurements
Literary Studies and Well-Being Structures of Experience in the Worldly Work of Literature and Healthcare
No full textThe literary arts represent and provoke experiences of understanding and emotion, and this open access study examines how the practical pursuit of well-being in healthcare reveals purposes at the core of our engagements with and understanding of literature itself.
During the past twenty years, much admirable work in the “health humanities” has focused upon what studies of literature contribute to the understandings and the practical work—the “worldly work”—of healthcare. Such a project aims at developing healthcare practitioners who bring greater care to those who come to them ailing or in fear or faced with terrible suffering. Literary Studies and Well-Being turns this inside out by examining the intergenerational caretaking of healthcare in a manner which allows us to comprehend the nature and discipline of literary studies in new ways.Open access was funded by The University of Oklahoma.Ye
Who Gets Hired at the Top? The Academic Caste System Theory in the Planning Academy
Get PDFThis study is the first to examine detailed faculty demographics and impacts of elite hiring networks in the planning academy. Institutional prestige significantly shapes faculty placements. Nearly half of planning faculty graduated from Berkeley, Massachusetts Institute of Technology (MIT), University of California, Los Angeles (UCLA), Cornell, and University of North Carolina (UNC)-Chapel Hill. Faculty are predominantly hired in similar or lower ranking programs with little upward mobility, after accounting for demographics and program factors. While race and gender did not have a significant relationship to placements, the findings demonstrate how status-based inequities are perpetuated through elite programs and constrain faculty representation.YesThis is an Accepted Manuscript of an article published by SAGE in the Journal of Planning Education and Research, Copyright © 2022 C. Aujean Lee DOI: https://doi.org/10.1177/0739456X221121611
Evaluation of Functionality and Service Life of Ultra-High Performance Concrete Link Slab Connections for Bridges
Get PDFStructural longevity and sustainability are rising priorities in bridge construction. Accelerated bridge construction is a response to such a demand, with a goal of providing bridges with a longer service life in a construction process more time and cost effective. Link slabs have been an attractive alternative to expansion joints by providing protection for rebar and underlying reinforcement from contaminant exposure. Though traditionally constructed with conventional concrete, there is a growing interest in ultra-high performance concrete (UHPC) in bridge construction due to its higher strength and durability. Utilizing UHPC in link slabs has the potential to further extend the service life of these connections and mitigate the frequency of costly repairs and replacements.
Using a non-proprietary UHPC mix developed at the University of Oklahoma, labeled “J3,” this research investigated its performance as a link slab construction material. The UHPC’s performance was compared to Class AA concrete, the Oklahoma Department of Transportation (ODOT) conventional mix standard for bridge construction. Both materials were used in constructing link slab specimens, with segments of these specimens subjected to durability and corrosion tests. A link slab of each concrete mix experienced cyclic loading prior to segmentation and durability testing. This provided insight to how in-service loading may affect the connection’s performance compared to a newly-constructed link slab. Tests conducted included rapid freeze-thaw cycling and accelerated corrosion testing.
UHPC specimens, pre-loaded or not, resisted loss of strength after 350 freeze-thaw cycles better than conventional concrete. Loading did slightly influence the UHPC mix’s performance but had a greater impact on the performance of the Class AA mix. Corrosion observations show the effects of testing were significantly more severe for conventional concrete. UHPC results are far more promising, with prior loading conditions having virtually no influence on these results. Overall, UHPC proved to be a superior construction material for link slabs by providing greater resistance to temperature effects and greater protection for reinforcement, offering a longer service life with fewer repairs.This thesis has been revised, with changes approved by the Graduate College on June 14, 2022. The original version is available at: https://hdl.handle.net/11244/33549
Designing Social Media Messages to Promote Action by Suicide Gatekeepers
Get PDFThe act of suicide is a tragic and yet prevalent occurrence in the U.S. younger population. Suicide prevention professionals and programs have focused on reaching not only individuals with suicide ideation, but also family, friends, and other acquaintances, who can be referred to as suicide gatekeepers. Social media provide platforms where health communicators can reach a large population. This research focuses on examining and testing the most effective message framing and wording of social media messages for positively influencing suicide gatekeeper intervention behavior on behalf of a friend or peer. The study first used the grounded theory method to collect and analyze data from suicide prevention specialists and online suicide prevention sources targeted to suicide gatekeepers. This research suggests that suicide gatekeepers need to detect suicide, engage suicidal peers in conversation, and connect suicidal peers with resources. In order to motivate suicide gatekeepers, social media messages should debunk current misconceptions with the constructs of significance of suicide threat, preventability of suicide through intervention, and beneficence of discussing suicide with those who have suicide ideation. In addition, message framing of empathy appeals may positively affect suicide gatekeeper state empathy and behavioral expectation.
The second part of this study used an experiment to test the influence of message construct (between subjects) and message frame (within subjects). Using four messages per participant (two gain-framed and two-loss framed), the survey randomized the 1,285 survey participants between the ages of 18 and 34 on two college campuses into the three message construct conditions (significance, preventability, and beneficence). The experiment found that gain-framed messages have a more positive influence on all the message outcome variables compared with loss-framed messages (perceived message effectiveness, self-efficacy, response efficacy, empathy, likelihood of social media message engagement, and behavioral expectation), and empathy mediates the relationship between gain- and loss-framed messages and behavioral expectation. Message construct condition and other mediation results were less substantial, although some evidence suggests that the significance message construct may have some advantages for social media messages designed for suicide gatekeepers. Limitations and areas for future study are discussed.
Communication Satisfaction and its Effects on Organizational Readiness to Change: A Quantitative District-Wide Study of Employees from a Technology Center
Get PDFAlthough literature establishes the importance of top-level executives’ communication during times of change, there is a lack of empirical research focusing on Communication Satisfaction’s role on Readiness for Organizational Change within a CTE (Career Tech Education) institution. Questions arise on how these two variables function during the change process. Within the context of change, this study demonstrated that Communication Satisfaction contributed to Job Satisfaction and Organizational Commitment by targeting both employees’ attitudes and behaviors. Using Bandura’s Social Cognitive Theory (SCT) as the theoretical framework for the research, this study explored what the relationship of Communication Satisfaction has on Organizational Readiness to Change and how employees’ thoughts and behaviors related to embracing new reforms that can affect the overall effectiveness of planned organizational change. Using several different survey instruments, employees reported on their level of Communication Satisfaction, Job Satisfaction, Organizational Commitment, and Organizational Readiness to Change. Structural equation modeling revealed Communication Satisfaction contributed to changes in both attitudes and behaviors suggesting that CTE institutions should emphasize incorporating various communication methods in their reform efforts to set the foundation for employees embracing change. This study focused on the role of both site/top level supervisors’ communication in creating a high level of job satisfaction and organizational commitment through attitudes and behaviors of employees. The study concludes with implications for theory and practice along with recommendations for further research
The tricuspid valve: mechanics, microstructure, modeling, and simulation
Get PDFThe objectives of this research include: (1) experimentally characterizing the multi-scale properties of the tricuspid valve (TV) leaflets, (2) linking the mechanical and microstructural properties of the TV leaflets to their intrinsic microstructure and morphology, (3) developing new in-silico methods for modeling the TV leaflet mechanical behaviors, and (4) providing the first benchtop characterization and in-silico implementation of TV leaflet pre-strains.
We first characterize the properties of tricuspid valve leaflets at the tissue, mesoscale, and microstructural scales. The tricuspid valve leaflets are mechanically characterized using our established biaxial testing protocols to elucidate how the choice of specimen size influences the observed mechanical behaviors. Then, we employ our polarized spatial frequency domain imaging device to analyze the intrinsic collagen fiber architecture of each leaflet. Our results demonstrate that the leaflet mechanical behaviors are linked to the underlying collagen fiber architecture, which adapts to the applied loading. Finally, one representative specimen for each tricuspid valve leaflet is imaged using a confocal microscope with multiphoton imaging and second harmonic generation. From the resulting high-fidelity reconstructed microstructures, we note that the four layers of the tricuspid valve leaflets contains unique leaflet-specific arrangements of collagen and elastin fibers.
As an extension of the multi-scale characterizations, we then experimentally derive the contributions of the tricuspid valve leaflet microstructures to the tissue-level mechanical behaviors. First, the tricuspid valve leaflets are dissected into the composite atrialis/spongiosa layers and the composite fibrosa/venricularis layers. Our mechanical characterization revealed that the isolated composite layers were stiffer than the intact specimen. On the other hand, the mesoscale polarized spatial frequency domain imaging results show that the composite leaflet layers had more flexible collagen fiber architectures that reacted more to applied tensions than the intact specimens. Next, we use an iterative enzyme-digestion procedure to understand how the collagen fibers and elastin fibers contribute to the tricuspid valve leaflet mechanical. The collagen-digested leaflets were more compliant in their high-tensile mechanical behaviors due to the removal of the primarily load bearing constituent—collagen. In contrast, the elastin-digested specimens were significantly stiffer than the control specimens, suggesting that elastin may play an important role in mediating the recruitment of collagen fibers and the transition to the high-tensile mechanical behaviors.
We next shift our focus to in-silico developments and provide two new studies on modeling the mechanical behaviors of the tricuspid valve leaflets. In the first study, a constant invariant-based mechanical characterization is used to isolate the contributions of the first invariant and the fourth pseudo-invariant to the leaflet mechanical behaviors. These data are fit with three candidate strain energy density functions to evaluate their fitting efficacy. Our analyses reveal that an exponential strain energy density function is more suited for capturing the tricuspid valve leaflet mechanical behaviors. Interestingly, the coupling between the invariants is crucial to capturing the leaflet behaviors, and this must be considered in future constitutive modeling developments. For the second study, we focus on an emerging topic in the soft tissue biomechanics community: data-driven material modeling. This new approach is promising since it does not require the a priori definition of a constitutive law and instead relies on large collections of experimental data. We compare this emerging modeling technique with common structural constitutive models used for the atrioventricular heart valve leaflets and find that it provides excellent predictions of the leaflet behaviors provided sufficient model training data.
We conclude this dissertation by experimentally characterizing the tricuspid valve leaflet pre-strains, which are an important consideration when linking in vitro properties with in vivo function. First, the pre-strains of all three tricuspid valve leaflets are characterized using stereo cameras equipped with a direct linear transformation and the reproducing kernel shape function method. Our results reveal that there are indeed pre-strains embedded within the tricuspid valve leaflets that are released upon dissection of the tissue from their in-situ anatomy. In addition to the pre-strain quantification, we compare different stress-free reference configurations to determine which may provide mechanical behaviors closest to those in vivo. Interestingly, we found that our existing preconditioning method does not appropriately restore the in vivo leaflet behaviors as expected, and, instead, the post-preconditioned configuration results in stiffer, more anisotropic material behaviors. In the second portion of this investigation, we implement pre-strains into a simplified tricuspid valve finite element benchmark we develop to evaluate new computational methods. The finite element simulations reveal that the pre-strains significantly altered tricuspid valve behaviors: at 20% pre-strain, the leaflet stresses nearly doubled and there was the significant formation of valvular regurgitation
What can urban school systems learn about supporting and retaining African-American women leaders from African-American women leading in public charter systems?
Get PDFAmerica is becoming more ethnically diverse, creating a significant demographic shift in the student composition in America’s public schools. To respond to the increase in student diversity, America’s systems and structures must evolve to support the unique needs of a nonhomogeneous population, including the dismantling of systems and structures that promote conscious and unconscious bias, discrimination, and unequal treatment for marginalized people.
The purpose of this study was to assess how public charter school systems retain and support diverse leaders, more specifically African-American women serving as the most senior leader in their organization. The factors considered were: (a) attractors to the organization, (b) how they are valued in/by the organization, (c) their ability to progress in the organization, (d) the level of development they experience in the organization, while also (e) evaluating their social, emotional, and professional well-being. To provide context to the research, the researcher used the Feminist Standpoint Theory (FST) and Intersectionality Theory (IT). Through these lenses, the researcher addresses the organizational factors and practices that have fostered an environment where African-American women in the senior-most level role in their public charter organization feel supported. The researcher used a qualitative, phenomenological study method to understand these factors and practices through the voices of 12 African-American women serving as the most senior leader in their charter organization. It was found that African-American women want to experience a psychologically safe work environment, work in organizations that are inclusive, have established community, and are making financial and professional development investments in African-American women leaders
Interaction Effects in Quantum Wires and One-Dimensional Incoherent Semimetals
Get PDFIn this thesis, we address the effect of interactions in low dimensional
systems. In the first part, using bosonization, we study a microscopic
model of parallel quantum wires constructed from two dimensional Dirac
fermions in the presence of periodic topological domain walls. The
model accounts for the lateral spread of the wave-functions
in the transverse direction to the wires. The gapless modes confined
to each domain wall are shown to form Luttinger liquids, which realize
a well known smectic non-Fermi liquid fixed point when inter-wire
Coulomb interactions are taken into account. Perturbative studies
on phenomenological models have shown that the smectic fixed point
is unstable towards a variety of phases such as superconductivity,
stripe, smectic and Fermi liquid phases. Here, we show that the considered
microscopic model leads to a phase diagram with only smectic metal
and Fermi liquid phases. The smectic metal phase is stable in the
ideal quantum wire limit . For finite , we find
a critical Coulomb coupling separating the strong coupling
smectic metal from a weak coupling Fermi liquid phase. We conjecture
that the absence of superconductivity should be a generic feature
of similar microscopic models. We also discuss the physical realization
of this model with moiré heterostructures. In particular, our model
may be of relevance to recent experiments on twisted bilayer
In the second part we study a two band dispersive Sachdev-Ye-Kitaev
model in 1+1 dimension. We suggest a model that describes a semimetal
with quadratic dispersion at half-filling. We compute the Green's
function at the saddle point using a combination of analytical and
numerical methods. Employing a scaling symmetry of the Schwinger-Dyson
equations that becomes transparent in the strongly dispersive limit,
we show that the exact solution of the problem yields a distinct type
of non-Fermi liquid with sub-linear temperature
dependence of the resistivity. A scaling analysis indicates that this
state corresponds to the fixed point of the dispersive SYK model for
a quadratic band touching semimetal