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Title: ADVANCING OPEN-SOURCE TOOLS FOR INDOOR ENVIRONMENTAL MONITORING AND BUILDING SYSTEMS CONTROLS USING WIRELESS SENSOR NETWORKS
Creator: Ali, Akram Syed
Date: 2021
Description: Incorporating data monitoring and visualization tools in buildings can provide a glimpse into their energy use, thermal performance, daily...
Show moreIncorporating data monitoring and visualization tools in buildings can provide a glimpse into their energy use, thermal performance, daily operation, and maintenance requirements. However, buildings have traditionally been monitored using hardware and software that are expensive, proprietary, and often limited in terms of ease of use and flexibility. Many existing buildings remain unmonitored or poorly monitored, leaving many opportunities for energy savings and improving indoor environmental conditions unaddressed. To this end, the goal of this research is to develop and demonstrate an open-source hardware and software platform for monitoring and controlling the performance of buildings and their systems, called Elemental. It is designed to provide real-time data on indoor environmental quality, energy usage, heating, ventilating, and air-conditioning (HVAC) operation, and other factors to its users, and provide easy development of building controls. It combines: (i) custom low power printed circuit boards (PCBs) with RF transceivers for wireless sensors, control nodes, and USB gateway, (ii) a Raspberry Pi with custom firmware acting as a backhaul, and (iii) custom software applications that manage data storage, device configuration and interface for querying and visualizing the data in real-time. The platform is built around the idea of a private, secure, and open technology for the built environment. Among its many applications, the platform allows occupants to investigate anomalies in energy usage, environmental quality, and thermal performance. It also includes multiple frontends to view and analyze building activity data, which can be used directly in building controls. This proposal describes the development process of the hardware and software used in the Elemental platform along with three distinct applications including: (1) deployment in a research lab for long-term data collection and automated analysis, (2) use as a full-home energy and environmental monitoring solution, and (3) building heating system automation at the room-level with the development and deployment of a custom radiator control. Through these applications, this work demonstrates that the platform allows easy and virtually unlimited datalogging, monitoring, and analysis of real-time sensor data with low setup costs. Low-power sensor nodes placed in abundance in a building can also provide precise and immediate fault-detection, allowing for tuning equipment for more efficient operation and faster maintenance during the lifetime of the building.
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Title: THREE ESSAYS ON CORPORATE FINANCE
Creator: Wang, Jianrong
Date: 2020
Description: This dissertation is comprised of three distinct but related essays in corporate finance. In the first essay, I examine how the CEOs paid with...
Show moreThis dissertation is comprised of three distinct but related essays in corporate finance. In the first essay, I examine how the CEOs paid with inside debt utilize corporate social responsibility activities to reduce firm risk taking. In the second and third essays, I explore the possible determinants of private placement. The first essay focuses on managerial incentive induced by debt-like compensation such as deferred compensation and defined benefit pensions. Building on cumulative prospect theory and instrumental stakeholder theory, I hypothesize that CEOs paid with debt in their own firms have risk-reduction incentives, and corporate social responsibility (CSR) activities mediate the relationship between debt-like compensation and firm risk taking. Furthermore, I argue that the mediated relationship between CEO debt-like compensation and firm risk taking is context dependent, and I propose that two contingencies, namely environmental dynamism and munificence, moderate the mediated process. My analyses, based on a large longitudinal dataset of nonfinancial US firms, lend strong support for these hypotheses. The second essay examines the impact of firm’s social capital on the cost of Rule 144A debt. I find that Rule 144A debt issuing firms headquartered in the high social capital county pay lower yield spread their peers. Furthermore, the finding suggests that the effect of social capital becomes weak when the issuers have more firm-specific public information and credit records. The relation between social capital and the cost of debt is contingent on industry environment. The results reveal that firms located in high social capital counties have low bankruptcy likelihood and low risk level after Rule 144A debt issuance. The third essay focuses on the role of prior technology alliances in the PIPE issuance. Relying on the data collected from Placement Tracker and SDC platinum, I empirically investigate the relationship between issuers’ technology alliance experiences and their PIPE offering contracts. I document that the greater alliance experiences at the time of the PIPE issuance, the smaller PIPE price discount and fewer contract terms that are favorable to investors. The results indicate that the technology alliance experience alleviates the information asymmetry between issuers and investors and improve issuers’ bargaining power. I further find that issuers with more alliance activities exhibit a more positive announcement effect and outperform in the long run. Moreover, the effect of technology alliance experience is stronger if the issuers partner with large firms, whereas the effect is weaker if the issuers are in high-tech industries.
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Title: GROWTH KINETICS OF LISTERIA MONOCYTOGENES DURING REHYDRATION OF DEHYDRATED PLANT FOODS AND SUBSEQUENT STORAGE
Creator: Wu, Zihui
Date: 2020
Description: Dehydrated plant foods do not support the growth of pathogenic bacteria. However, once rehydrated, the high-water activity and neutral pH of...
Show moreDehydrated plant foods do not support the growth of pathogenic bacteria. However, once rehydrated, the high-water activity and neutral pH of these foods may support the growth of pathogens, such as L. monocytogenes, during storage. The goal of this study was to examine the growth kinetics of L. monocytogenes during 5, 10, and 25°C storage on potatoes, carrots, and onions after rehydration with 5 or 25°C water. Fresh plant foods were dehydrated at 140°F (60°C) for 24 h. A 4-strain rifampicin-resistant L. monocytogenes cocktail was inoculated onto dehydrated plant foods at 4 log CFU/g and dried for 24 h. Plant foods were rehydrated in 4-volumes of 5 or 25°C water for 24 h. At various timepoints during rehydration, 30 g of sample was removed and drained for 10 min. Samples were homogenized 1:10 with BLEB and the homogenate was plated onto BHIRif for enumeration. After rehydration, samples were drained and portioned into deli-style containers for storage at 5, 10, and 25°C and L. monocytogenes was enumerated at 1, 3, 5, and 7 d. Triplicate samples were assessed at each timepoint and three independent trials were conducted. Growth rates were determined using DMFit and data were statistically analyzed using Student t-test (α=0.05). Overall, the growth rates of L. monocytogenes during storage of potatoes and carrots were higher when rehydrated with 5°C water compared to 25°C water. The highest growth rate on potatoes was 3.51±0.43 log CUF/g per d with 5°C water rehydration and 25°C storage, resulting in a 1 log CFU/g increase in 0.29 d (7.0 h). When rehydrated with 25°C water and 25°C storage, the growth rate was significantly lower at 1.03±0.01 log CFU/g per d. The highest growth rate of L. monocytogenes on carrots was 0.68±0.07 log CUF/g per day when rehydrated with 5°C water and 10°C storage, resulting in a 1 log CFU/g increase in 1.47 d (35.3 h). For onion, L. monocytogenes was below the level of enumeration during storage at 5°C for both water rehydration temperatures and also for 10°C storage with 5°C water rehydration. The highest growth rate was 0.46±0.11 log CFU/g per d, resulting in a 1 log CFU/g increase in 2.17 d. The results of this study can aid in determining appropriate time and temperature control for safety for dehydrated potatoes, carrots and onions during rehydration and subsequent storage.
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Title: Attitudes of Adults Treated for Depression Toward Technology-Assisted Therapy
Creator: Johnston, Winter D.
Date: 2021
Description: Depression is associated with functional impairment (Saarni et al., 2007), high economic costs (Cuijpers et al., 2007; Greenberg & Birnbaum,...
Show moreDepression is associated with functional impairment (Saarni et al., 2007), high economic costs (Cuijpers et al., 2007; Greenberg & Birnbaum, 2005), and loss of quality of life (Rapaport et al., 2005), and has been named a major reason for illness-related disability worldwide (Vos et al., 2013). Barriers to treatment include being physically limited to access services (Apolinario-Hagen et al., 2018), fear of stigmatization, desire to handle the problem on ones’ own, lack of confidence in the healthcare system (Königbauer et al., 2017), lack of motivation to change, and negative perception of psychological and/or drug treatments (Richards et al., 2015). As technological options have advanced and become more reliable, they have become tools to improve access to care and reduce barriers. Clinicians’ attitudes have been studied pertaining to incorporating different technology modalities into traditional therapy; however, client attitudes are less explored. The present study aims to (1) explore client attitudes towards hypothetical technology-assisted interventions, (2) assess the relative preferences for various technology-assisted interventions, (3) identify correlates of the participant’s preference of different technology-assisted interventions, including: (a) attitudes towards technology-assisted therapy, (b) sociodemographic variables, (c) help-seeking variables (seeking health information, use of technology outside therapy, awareness of technology-assisted options for therapy), (d) previous therapy experience (therapeutic approach, helpfulness of therapy, number of previous therapists), and (4) assess if working alliance with participants’ most recent therapist moderated the effect of therapist condition (current/recent or new) on preferences. The technology options in this study are videoconferencing, online therapy, mobile phones, and virtual reality/avatars. Individuals were asked to imagine continuing therapy using these technological options. Participants viewed videos demonstrating how each technology is used in a therapeutic setting and provided their attitudes and preferences afterwards. The participants consisted of adults who currently or in the recent past have received therapy to treat any severity of depression. Overall, participants had a positive attitude towards technology-assisted therapy. Participants’ relative preference for various technology-assisted interventions and their first-choice modality of therapy did not differ by whether the participant was to keep their same therapist or start therapy with a new therapist. A variety of determinants were associated with greater preference towards the different modalities. Lastly, the strength of working alliance did not moderate whether preferences differed based on staying with the participant’s current/most recent therapist or starting with a new therapist. Limitations, strengths, and conclusions are also discussed.
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Title: ENERGY METABOLISM OF CHLAMYDIA PNEUMONIAE
Creator: McMillan, B. Julia
Date: 2021
Description: Chlamydia pneumoniae is a gram-negative bacterium that infects the humanrespiratory tract. It causes acute pneumonia and has been linked to...
Show moreChlamydia pneumoniae is a gram-negative bacterium that infects the humanrespiratory tract. It causes acute pneumonia and has been linked to several chronic diseases including cardiovascular disease, asthma, and some neurological diseases. C. pneumoniae primarily exists in two forms, the elementary body (EB) and the reticulate body (RB). The EB infects host cells and the RB replicates inside them. In order to survive in and out of the host, it was thought that C. pneumoniae RBs obtain host ATP to use for energy, making it an “energy parasite.” However, genomic analysis indicated that it was also possible for C. pneumoniae to create ATP from its own respiratory chain using the Na + pump NADH Ubiquinone Oxidoreductase (Na + -NQR). Neither the details of the energy parasite theory nor the possibility of C. pneumoniae creating its own energy had been experimentally explored. This project used a pharmacological approach to explore C. pneumoniae host energy consumption at various developmental stages, examine a mechanism that the bacterium could use to produce its own energy, and assess the importance of a balanced Na + /H + gradient for energy production and maintaining homeostasis. Based on the genomic analysis, it was thought that C. pneumoniae would rely heavily on host ATP in the EB form but not the RB form, that inhibiting Na + -NQR would slow bacterial growth, particularly in RBs, and that disrupting the Na + /H + gradient would significantly reduce RB infection. The results indicate that in the EB form, C. pneumoniae relies on host ATP and requires a balanced Na + /H + gradient, but disrupting Na + -NQR does not hinder its growth. In the RB form, C. pneumoniae is not dependent on host ATP, nor on its own respiratory chain ATP, and is not impacted by an unbalanced Na + /H + gradient. Therefore, the energy parasite hypothesis appears to apply to C. pneumoniae EBs but not RBs. Furthermore, established C. pneumoniae infections are excellent at compensating for various environmental conditions and sources of energy, which proves challenging for drug design against C. pneumoniae.
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Title: TOWARD A MODERN CIVIC MONUMENTALITY: ARCHES, VAULTS, AND DOMES IN POSTWAR AMERICAN ARCHITECTURE
Creator: Amado Petroli, Marcos
Date: 2021
Description: This dissertation studies the use of arcuated structures in post-World War II American civic buildings, which serve both to answer the...
Show moreThis dissertation studies the use of arcuated structures in post-World War II American civic buildings, which serve both to answer the practical and functional demands of the architectural program, and to communicate a distinct and hierarchical character inherent to the very genesis of civic architecture. This research demonstrates how a generation of multicultural architects, educated in the academic tradition, with the collaboration of structural engineers, participated in the expansion of the syntax and vocabulary of modern architecture at a time when the language of monumentality was also being discussed. In doing so, they moved away from a Bauhaus-German doctrine that promoted a universal, orthogonal, and homogeneous architectural language, serving all types of buildings. In this context, this research redefines the relationship between academic tradition and modern approaches to monumentality in American architecture, which are usually seen as antagonistic languages. To test the hypothesis that these new arched forms, of high structural engineering, were linked to both modern and academic aspects, and more precisely, French roots, this research addresses three main issues: (i) the mistrust of the new monumentality, which was often mystified and associated with totalitarian regimes; (ii) the analysis of this production through pioneering case studies in postwar arched structures; and (iii) the relationship between academic tradition and modern architecture, with an emphasis on the theory of "architectural character." Finally, this research concludes that the construction of this civic monumentality in the United States was not only a rational response to special programs and an opposition to the universal character of modern buildings, but also the result of an immigration of more inclusive ideas, which, reacting with the local tradition and heritage of the Beaux-Arts system, gave rise to an autochthonous American production.
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Title: Towards a Self-Programmable Storage Solution in Extreme-Scale Environments
Creator: Devarajan, Hariharan
Date: 2021
Description: Traditional compute-centric scientific discovery has led to a growing gap between computation power and storage capabilities. However, in the...
Show moreTraditional compute-centric scientific discovery has led to a growing gap between computation power and storage capabilities. However, in the data explosion era, where data analysis is essential for scientific discovery, slow storage systems led to the research conundrum known as the I/O bottleneck. Scientists have proposed several optimizations to address the I/O bottleneck. However, selecting and applying the appropriate optimization is a complex task, often left to the users. Additionally, the explosion of data has led to the proliferation of applications as well as storage technologies. This has created a complex matching problem between diverse application requirements and heterogeneous storage resources for the users. We need to move towards a Self-Programmable storage system that can automatically understand the I/O requirements of applications, transparently leverage the heterogeneity of storage, and reconfigures itself dynamically by utilizing application and storage information. In this work, we present the Jal System for building Self-Programmable storage. The Jal System consists of three layers: the application layer, the transfer layer, and the storage layer. The application layer uses automatic extraction of I/O requirements from applications using a source-code-based profiler. The storage layer defines a data abstraction, using a shared log store, to efficiently unify heterogeneous storage resources under a single platform. Finally, the transfer layer defines data management algorithms that consider multi-application and multi-storage information to optimize data operations. Additionally, we illustrate the benefits of utilizing the technologies within the Jal System on modern scientific AI applications. Our evaluations have demonstrated that each technology within the Jal System can accelerate I/O for modern scientific workflows. We have implemented software, tools, and system libraries for modern HPC systems. In the future, we envision building a fully integrated system that efficiently utilizes all the Jal System technologies. Additionally, we plan to extend the strategies and techniques in Jal System to other scientific domains such as AI and IoT.
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Title: MITOCHONDRIA RELOCALIZATION IN CHLAMYDIA TRACHOMATIS INFECTED HFF-1 CELLS
Creator: Shuppara, Alexander Mitchell
Date: 2021
Description: Chlamydia trachomatis is an infectious, gram-negative, obligate intracellular human bacterial pathogen. With over eight hundred million cases...
Show moreChlamydia trachomatis is an infectious, gram-negative, obligate intracellular human bacterial pathogen. With over eight hundred million cases worldwide, C. trachomatis is the most prevalent sexually transmitted infection. It manifests as either trachoma, lymphogranuloma venereum, or other urogenital tract sequelae. As an intracellular pathogen, Chlamydia must scavenge for essential metabolites from establishing networks with its host’s organelles including Golgi apparatus, endoplasmic reticulum, endocytic vesicles, mitochondria, and the cytoskeleton. C. trachomatis was considered an “energy parasite” that is entirely dependent on their host’s ATP production. Yet, recent mitochondrial inhibitor-based evidence suggests that C. trachomatis possess a sodium-based energy gradient for ATP production. Despite this finding, literature on specific interactions between host cell mitochondria and C. trachomatis requires further definition. This project evaluates mitochondrial dynamics changes from C. trachomatis infection in the human foreskin fibroblast cell line, HFF-1. We first defined C. trachomatis growth characteristics in HFF-1 over 36 hours-post infection. Next, we determined changes in mitochondrial dynamics and content throughout infection using immunofluorescent and immunoblotting techniques. observations on infected cells show mitochondrial morphology changes from an elongated appearance at the early stages of infection to fragmented in the late infection stages. Unlike in HeLa cells, HFF-1 remains in a normal distribution throughout the cell and we do not observe mitochondria relocalizing toward the inclusion. By studying mitochondrial relocalization dynamics, new insights into the dynamic and parasitic relationship of Chlamydia and its host can be discovered.
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Title: Reconfigurable High-Performance Computation and Communication Platform for Ultrasonic Applications
Creator: Wang, Boyang
Date: 2021
Description: In industrial and medical applications, ultrasonic signals are used in nondestructive testing (NDT), medical imaging, navigation, and...
Show moreIn industrial and medical applications, ultrasonic signals are used in nondestructive testing (NDT), medical imaging, navigation, and communication. This study presents the architecture of high-performance computational systems designed for ultrasonic nondestructive testing, data compression using machine learning, and a multilayer perceptron neural network for ultrasonic flaw detection and grain size characterization. We researched and developed a real-time software-defined ultrasonic communication system for transmitting information through highly reverberant and dispersive solid channels. Orthogonal frequency-division multiplexing is explored to combat the severe multipath effect in the solid channels and achieve an optimal bitrate solution. In this study, a reconfigurable, high-performance, low-cost, and real-time ultrasonic data acquisition and signal processing platform is designed based on an all-programmable system-on-chip (APSoC). We designed the unsupervised learning models using wavelet packet transformation optimized by convolutional autoencoder for massive ultrasonic data compression. The proposed learning models can achieve a compression accuracy of 98% by using only 6% of the original data. For ultrasonic signal analysis in NDT applications, we utilized the multilayer perceptron neural network (MLPNN) to detect flaw echoes masked by strong microstructure scattering noise (i.e., about zero dB SNR or less) with detection accuracy above 99%. It is of high interest to characterize materials using ultrasonic scattering properties for grain size estimation and classification. We successfully designed an MLPNN to classify the grain sizes of materials with an accuracy of 99%. Furthermore, a software-defined ultrasonic communication system based on the APSoC is designed for real-time data transmission through solid channels. Transducers with a center frequency of 2.5 MHz are used to transmit and receive information-bearing ultrasonic waves in solid channels where the communication bit rate can reach up to 1.5 Mbps.
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Title: Modeling the Aerodynamic Response to Impulsive Active Flow Control
Creator: Asztalos, Katherine
Date: 2021
Description: In unsteady aerodynamics the response to external disturbances can depend significantly on the initial condition, and the extent to which this...
Show moreIn unsteady aerodynamics the response to external disturbances can depend significantly on the initial condition, and the extent to which this impacts the ability to model the flowfield can vary. In this work, we look to develop a model that can capture and predict the long-time response to actuation, which we suspect to be sensitive to the instantaneous state. We investigate whether a physical understanding of the short-time response to impulsive actuation can be obtained, with the goal of understanding the observed physical phenomenon present in the immediate response to this type of actuation. We find that the response to impulsive actuation is sensitive to the instantaneous wake, and that the short-time response is directly proportional to the time rate of change of the actuation input. Computational simulations of a stalled NACA 0009 airfoil subject to leading-edge synthetic jet actuation were performed. Full state information, as well as force response measurements, were collected using an immersed boundary method (IBM) numerical code. The numerical simulations performed sought to characterize the response to actuation by varying the actuation parameters, such as the strength, direction, and phase at which the onset of actuation occurs. It was found that the long-time response to actuation can be sensitive to the instantaneous wake state at the onset of actuation. The ability to extract models that describe the complex behavior of the system provides additional insight into the dominant features governing the response of such systems, as well as achieves predictive capabilities of the systems' response. The data-driven models, which are identified using variants of dynamic mode decomposition, can capture both the short- and long-time response of the system to actuation. Predictive models are identified using multiple trajectories of data corresponding to varying the phase of vortex shedding at which the onset of actuation occurs. These models achieve accurate predictions for off-design cases as well. It is also shown that multiple control objectives with the same actuator can be achieved. Classical theory aids in understanding the physics governing unsteady aerodynamic motion and the response to disturbances. Theoretical models are developed using the assumptions from classical unsteady aerodynamic theory, which provide insight into the forms that the data-driven models take. The effect of short-duration momentum injection actuation is modeled through a combination of source/sink, doublet, and vortex elements. Regardless of the precise elements used in the theoretical model, the lift response is composed of a contribution directly proportional to the rate of change of actuation strength, and a contribution that persists after the actuation burst ends that arises due to the enforcement of the Kutta condition. Methodologies that retain the physics inherent to the system by projecting the governing equations of motion onto a well-suited basis are extremely valuable for gaining physical insight and understanding into the dynamics of the flowfield. A new methodology is proposed for extracting spectral content from systems with limited data available using projection-based modeling approaches. There are challenges associated with using modal decomposition-based modeling techniques for systems exhibiting large transient dynamics due to external inputs, which is applicable in this particular instance and for related systems. The methodology presented here shows how the dynamics of this system can be understood through analysis of optimal finite-time horizon transient energy growth, applied to reduced-order models identified using actuation response data with either data-driven or physics-based models. A novel methodology is proposed to guide future experimental actuation design to achieve maximal response by considering an optimal forcing mode, identified from considering the optimal perturbation of the full unactuated system, which maximizes a given output.
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Title: Effects of the Silicon Content on the Dimensional Changes of Electrodes for Lithium-ion Cells: An Electrochemical Dilatometry Study
Creator: Rodrigues Prado, Andressa Yasmim
Date: 2021
Description: The continuous growth of the electric vehicle market has significantly increased the demand for Li-ion batteries (LIBs). However, state-of-the...
Show moreThe continuous growth of the electric vehicle market has significantly increased the demand for Li-ion batteries (LIBs). However, state-of-the-art LIBs are not yet able to meet the EV industry demand for high energy density and long cycle life rechargeable batteries, prompting efforts to improve the performance of Li-ion cells. In this context, silicon became the most promising next-generation active material for LIBs negative electrodes, especially because Si can significantly increase the lithium storage capacity of the commonly available anodes. Nonetheless, commercialization of Si-based electrodes has been hindered by the poor electrochemical performance of these electrodes, which is mainly attributed to the severe volumetric changes in the silicon particles related to the electrochemical reactions with Li. Since the electrodes are composites with a complex combination of various materials interspaced by pores, the electrode-level swelling may differ significantly from the particle-scale expansion. Furthermore, an increase in electrode thickness due to silicon expansion can have a direct effect on how Li-ion cells are designed, as the accommodation of electrode dilation requires additional cell space to prevent significant dynamic stresses. Thus, the actual volumetric energy density of a LIB cell depends on the electrode swelling, since the higher the magnitude of the electrode expansion, the lower the gains in energy density. Monitoring the electrode dilation is just as important as the electrochemical evaluation when designing cells with Si-based anodes.In this work, we use high-resolution operando electrochemical dilatometry to quantify the (de)lithiation-induced expansion/contraction of silicon, blended silicon-graphite and graphite electrodes, upon electrochemical cycling. We evaluate the relationship between electrode capacity and dilation and observe that while the lithiation capacity improved with increasing the silicon content, the electrode swelling is highly aggravated. For silicon-rich anodes, the electrode dilation can be higher than 300%, and the expansion profile consists of a combination of slow swelling at low levels of lithiation followed by an accelerated increase at higher lithium contents. This non-linear dilation allows for narrowing the swelling by limiting the electrode capacity. In addition, we investigate how electrode properties, such as porosity, affect the dilation profile, and quantify the irreversible expansion of the electrodes. Finally, we discuss some of the challenges associated with the dilatometry technique and suggest experimental approaches for obtaining consistent and reliable data.
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Title: On the Study of Successful Derivatives: A Holistic Approach to the Standardization of Financial Innovation
Creator: Schoinas, Konstantinos Georgios
Date: 2021
Description: This dissertation attempts a contribution toward a much-needed holistic understanding surrounding the trading dynamics of exchange-based...
Show moreThis dissertation attempts a contribution toward a much-needed holistic understanding surrounding the trading dynamics of exchange-based derivative products. The latter proxying such products’ commercial performance. Hence, upon identifying the lack of a measurement standard as the underlying reason for the attested and motivating knowledge deficit, we adopt a two-step approach for the development thereof: At first an integrated conceptual framework is established and, subsequently, a normalization standard is derived. In result, across-product trading dynamics are rendered directly comparable; arguably, for the first time ever. Furthermore, we also explore the existing postulation of balanced liquidity commitments between the groups of hedgers and speculators and posit the construct of a corresponding temporarily stable equilibrium. The latter serves as the first dimension on which the developed measurement standard may be applied. Accordingly, we conduct empirical research predicated on an extensive dataset with daily trading activity and, just as theorized, reject the hypothesis that the aforementioned speculator-hedger ratio is non-stationary. We then proceed in studying the trading dynamics of individual derivatives, implementing the developed standard by means of longitudinal analyses for second time. To a large extent our results do not contradict the body of related literature, which however has been essentially based on heuristic approaches to this time. Nevertheless, in its course, this study also highlights the need to shift the entire paradigm of studying individual derivatives trading success – from a single-faceted – to two separate effects: one anchored to the short term ‘steam gathering’ capacity of newly launched products and another associated with the notion of established products’ longevity. Altogether then, this study aspires to serve as a solid first step in systematically answering Webb’s (2018) call to confront the still unknown causes of derivatives’ success, or lack thereof.
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Title: Evaluation of Bax∆2 Positive-Staining in Skin Samples Using Two Immunohistochemical Methods
Creator: Basheer, Sana
Date: 2021
Description: BaxΔ2 is a pro-death and tumor suppressor protein that sensitizes cells to certain chemotherapies. Previous diaminobenzidine (DAB)-based...
Show moreBaxΔ2 is a pro-death and tumor suppressor protein that sensitizes cells to certain chemotherapies. Previous diaminobenzidine (DAB)-based staining revealed that Bax∆2 is found in all organs, including breast, colon, and skin tissues. In the skin, the Bax∆2 positive cells were mainly found in the basal cell layer of the epidermis with a few Bax∆2 positive cells in the connective tissue of the dermis, although their cellular identity was unknown. Previous literature has shown that melanin, which is found throughout the cells of the epidermis, is a brown color that provides no visual contrast to the DAB staining. While the DAB-based immunostaining showed cells that appeared to be Bax∆2 positive, this result needed to be confirmed. For this, a set of human skin samples from normal and cancerous tissue of various patients was examined. The co-staining of these samples for Bax∆2 and basal cells using immunofluorescence revealed that the apparent Bax∆2-positve DAB staining in epidermal basal cells and squamous cell carcinoma as false-positive, but the Bax∆2 positive cells found in the dermal connective tissue were not false positive—which is consistent with both previous DAB-based and fluorescence-based immunostaining. Using co-immunostaining for Bax∆2 with different cellular markers, the Bax2-positive cells in the connective tissue were identified potentially as macrophages and fibroblasts. Further studies are required to confirm the identity of the Bax∆2 positive cells in the connective tissue.
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Title: Understanding the effect of temperature, strain and grain size on the stress relaxation behavior of Ni-base and steel alloys
Creator: Reny, Julia
Date: 2021
Description: Stress relaxation research is very valuable as it provides information on how materials relieve stress under a constant strain. In...
Show moreStress relaxation research is very valuable as it provides information on how materials relieve stress under a constant strain. In applications where parts are submitted to a constant deformation, it is important to know that regions containing notches or stress concentrations will be able to relax enough to avoid the formation of cracks during operations. In this study, the stress relaxation behaviors of experimental Ni-base superalloy RRHT5 and Pyrowear 53 steel alloy were investigated. Tests were conducted under different conditions, varying temperature, initial strain, and grain size to explore the influence of each of these factors. The stress relaxation test data was used to calculate apparent activation volumes which can be correlated with plastic deformation mechanisms governing the stress relaxation. Understanding these mechanisms and identifying how specific factors influence them is essential to further control and optimize the design and processing of materials to obtain the best properties. Depending on the test conditions, the stress relaxation underwent one or two stages dominated by different mechanisms. These governing mechanisms were considered to be either dislocation-dislocation interactions, dislocation rearrangement, dislocations spreading from localized slip bands or dislocation-precipitate interactions.
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Title: High School Mathematics Teachers’ Conceptions of Nature of Mathematics (NOM) and How Prior Learning Environments Affect These Conceptions
Creator: Elefteriou, Katherine
Date: 2023
Description: Literature shows that the Nature of Mathematics Knowledge (NOMK) dates back to the era of Plato and Aristotle (Dossey, 1992). It suggests that...
Show moreLiterature shows that the Nature of Mathematics Knowledge (NOMK) dates back to the era of Plato and Aristotle (Dossey, 1992). It suggests that mathematics teachers’ beliefs, views, conceptions, and preferences about NOM influence the way in which they teach mathematics. It is important to understand how these conceptions are formed, which may evolve consciously or unconsciously from their experiences. Teachers’ experiences as students of mathematics, their family, school environment, cultural, and social experiences influence their behavior including their decisions, actions, class organization, learning activities, and students’ achievement (Beswick, 2012; Ernest, 2008; Thompson1984). Yet, there is no NCTM standard on NOM (Gfeller, 1999).The purpose of the present study was to assess high school mathematics teachers’ NOMK conceptions, and to explore how these conceptions have been influenced by their personal and educational experiences as students in learning mathematics. Another objective of this study was to explore whether the teachers’ years of mathematics teaching experience, and their level of education have any influence on their NOMK beliefs. The sample consisted of 52 high school mathematics teachers, who were certified to teach secondary mathematics, and who had at least three years of mathematics teaching experience. Two instruments were used to collect the data, 1) the VNOM D instrument to assess the teachers’ beliefs regarding the NOMK aspects, and 2) the demographics instrument to collect information on the teachers’ demographics, and on their experiences as students of mathematics. Interviews were also used to enhance the findings. Results showed that participants had strong beliefs regarding their NOMK, and that their years of experience, and level of education influenced their NOMK beliefs.
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Title: MICROSTRUCTURE AND MECHANICAL PROPERTIES OF DISCONTINUOUSLY PRECIPITATED NI-CO-AL ALLOYS
Creator: Ho, Kathy
Date: 2022
Description: The study of high temperature structural materials has been one of great interest and immense focus in recent years of research and...
Show moreThe study of high temperature structural materials has been one of great interest and immense focus in recent years of research and development. With the capability of catering to specific needs and applications while being commercially cost-effective, these materials can be synthesized using various types of methods and materials for a large range of applications. In order to implement the advantageous properties of these materials for practical use in service, empirical data relating to the material and mechanical properties of these high temperature structural alloys must first be obtained. This can be achieved through numerous processing methods. One particular method involves precipitation strengthening. Two types of transformation modes include discontinuous and continuous precipitation. Discontinuous precipitation (DP) nucleates at high angle, incoherent grain boundary, grows through grain boundary diffusion, and produces a lamellar structure consisting of alternating layers of γ and γˡ (Ephler, 2004). Continuous precipitation (CP) nucleates within the grain, is controlled through volume diffusion producing, and results in a homogeneous distribution of equilibrium composition precipitates with a spherical/cuboidal morphology. Since both modes of transformation possess a chemical driving force, resulting from the supersaturation of solute, the coexistence of both DP and CP transformation in a material is possible. However, as demonstrated from past studies, the presence of a partial DP transformation in structural alloys is undesirable as detrimental effects on mechanical properties are observed. As a result, numerous studies have focused on suppressing DP all together. In 1972 Erhard Hornbogen hypothesized that a fully DP transformed material would yield superior mechanical properties, similar to pearlite formation in steel, since the lamellar structure would increase barriers to dislocation movement (Hornbogen, 1972). As a result, recent studies have redirected their focus in an effort to encourage DP transformation to completion for improved mechanical properties. Therefore, the purpose of this work was to 1) determine the aging conditions under which a complete, 100% DP transformation would be achieved in select alloys, 2) determine the conditions where optimal precipitate size via CP transformation is obtained to effectively use precipitation strengthening without the concern of over-aging, 3) experimentally compare the material and mechanical properties between 100% DP aged samples and CP aged samples consisting of the optimal precipitate size, 4) compare the mechanical properties between alloys that have undergone a complete DP transformation to commercial alloys currently used in service, and 5) provide empirical data to verify Hornbogen’s claim. The results from this work indicated that 1) a lower aging temperature promote DP transformation while a higher temperature promotes CP transformation, 2) a smaller grain size prior to aging was more favorable for DP transformation while larger grains were favorable for CP transformation, 3) a complete DP transformation was observed for Alloy 9 and Alloy 10 after aging at 500°C for 4 hours and 550°C for 4 hours, 4) Alloy 1, Alloy 3, and Alloy 5 were potentially undergoing a different type of transformation at lower DP aging temperatures, where β phase was present, 5) optimal precipitate size for effective use of precipitation strengthening (CP transformation) was achieved under CP aging conditions 700°C-1HR for Alloy 10 and 750°C-1HR for Alloy 9 and the forged stock bar, 6) a small fraction of DP consistently formed at the grain boundaries of the CP aged samples for all alloy samples, indicating that the nucleation of DP was quick, but growth was limited, 7) mechanical properties of the DP aged samples for Alloy 9, Alloy 10 and the forged bar were superior to their corresponding CP aged samples in terms of the hardness, UTS, and yield stress, but were less ductile than the CP aged samples, and 8) the mechanical properties of DP aged samples for Alloy 9, Alloy 10, and the forged bar were comparable, and at times superior, to the commercially available alloys. Due to limited prior research conducted on the mechanical properties of DP alloys, this investigation serves as a pioneering effort experimentally determine if the mechanical properties of completely DP transformed material are superior to that of CP transformed material, aged to optimal precipitate size, while collecting empirical data to verify Hornbogen’s claim.
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Title: COMPREHENSIVE ANALYSIS OF EXON SKIPPING EDITS WITHIN DYSTROPHIN D20:24 REGIONS
Creator: Niu, Xin
Date: 2020
Description: Exon skipping is a disease modifying therapy that operates at the RNA level. In this strategy, oligonucleotide analog drugs are used to...
Show moreExon skipping is a disease modifying therapy that operates at the RNA level. In this strategy, oligonucleotide analog drugs are used to specifically mask specific exons and prevent them from being included in the mature mRNA. Exon skipping can also be used to restore protein expression in cases where a genetic frameshift mutation has occurred, and this how it is applied to Duchenne muscular dystrophy, DMD. DMD most commonly arises as a result of large exonic deletions that juxtapose flanking exons of incompatible reading frame, which abolishes dystrophin protein expression. This loss leads to the pathology of the disease, which is severe, causing death generally in the second or third decade of life. Here, the primary aim of exon skipping is to restore the reading frame by skipping an exon adjacent to the patient’s original. While restoring some protein expression is good, how removing some region from the middle of protein affects its structure and function is unclear. Complicating this in this case is that the dystrophin gene is very large, containing 79 exons. Many different underlying deletions are knowns, and exon skipping can be applied in many ways. It has previously been shown that many exon-skip edits result in structural perturbations of varying degrees. Very few studies are focused on the protein biophysical study and it is still basically unclear whether and how such editing can be done to minimize such perturbations. In order to provide the solid evidences which prove the significant variation among those cases (especially for the clinically relevant cases) and better understanding the general principles of “what makes a good edit”, we examine a systematic and comprehensive panel of possible exon edits in a region of the dystrophin protein. The domain D20:24 of dystrophin rod region are selected for its entirety which is separated by hinge region (mostly random coiled structure) and addition of other STRs will not disrupt the structure stability. Also D20:24 regions lie in the Hot Spot region II (HS2) which holds the most number of DMD patients. During the comprehensive scan, we identify for the first time, exon edits that appear to maintain structural stability similar to wild-type protein and those clinically relevant edits. Then we figure out the factors that appear to be correlated with the degree of structural perturbation, such as the number of cooperative protein domains, as well as how the edited exon structure interacts with the protein domain structure. Our study is the first systematic and comprehensive scan for an entire multiple STRs domain. This would help us understand the protein nature of various exon skipping edits and provide useful target for clinical treatment. Also the knowledge we learned may be applied to produce more sophisticated CRISPR edits in the future work.
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Title: CONCEPTUAL COST ESTIMATION MODEL FOR BRIDGES WITH RESPECT TO ABC METHODS
Creator: Rajeei, Farshad
Date: 2020
Description: As the need for renovating and repairing structurally deficient and functionally obsolete bridges is increased, employing innovative methods...
Show moreAs the need for renovating and repairing structurally deficient and functionally obsolete bridges is increased, employing innovative methods which can lead to shorter construction time, better quality, longer durability, and less life-cycle costs become more popular in transportation agencies.Developing a model that has the capability of estimating the total construction cost of ABC projects and compare them with conventional methods costs [without using these methods] will help decision-makers at DOTs in understanding and assessing the benefits and costs of ABC methods at the planning phase of a project and in return, will lead to the elaboration in the use of ABC methods versus the conventional ones. But this decision making process is complicated since the number of executed ABC projects, especially those which done by SIBC and SPMT [two superstructure replacement method] is limited and as a result; there is a lack of historical knowledge to estimate the associated cost of these methods in future projects. Factors affecting this process include but are not limited to: construction costs, user costs, quality of work, impact on traffic, the safety of road users and construction workers, and the impact on surrounding communities and businesses. The main aim of this study is to make a model to estimate additional costs of using SIBC and SPMT methods and the saving in user costs.
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Title: Comparison of an Ideal Point and Dominance IRT Model on the Detection of Differential Item Functioning with DFIT
Creator: Spizzuco Jr, Daniel
Date: 2019
Description: Item response theory (IRT) models can assume a variety of forms including,notably, dominance and ideal point-based probability distributions....
Show moreItem response theory (IRT) models can assume a variety of forms including,notably, dominance and ideal point-based probability distributions. But researchers haveonly recently begun to explore issues related to the above distinction. The current studytherefore examines whether model-data fit and rates of differential item functioning (DIF)detection remain comparable when data are analyzed via the ideal point-based generalizedgraded unfolding model (GGUM) vs. the dominance-based graded response model (GRM).To address these issues, item response data were simulated to contain dominance,ideal point and mixed response processes, and DIF and impact scenarios. Results indicatedthat model-data fit and DIF detection accuracy were not as closely aligned as anticipated.Overall, the GGUM fit data better than the GRM to the extent that any ideal point processeswere present, while the GRM was slightly better at fitting dominance-only data. With noimpact, however, the GGUM fit all embedded response data types better than the GRM.Results were mixed among impact scenarios. This pattern was found in both no DIF and DIFscenarios.Several points were made with respect to the DIF portion of the study. First, Type 1error rates were in most cases quite conservative for both models. Second, study-wide,more power emerged with dominance as compared to ideal point data for both models.Moreover, in no impact conditions, slightly more power accrued via the GGUM fordominance and ideal point data. With impact, however, the GRM produced somewhat morepower across data types. Third, in terms of DIF patterns/sources, power was high for bothmodels when DIF was embedded on the full set of location/threshold parameters, andlower with fewer differentially functioning (DF) location/threshold parameters. Notably,the GGUM was slightly more powerful in the fewest DF location/threshold scenarios, andthe GRM was more powerful in the most DF location/threshold scenarios. Fourth, neithermodel performed well in the complex within-item cancelling DIF scenarios. These patternsgenerally occurred in both uniform and non-uniform scenarios. The paper concludes with apresentation of recommendations, study limitations and issues for future research.
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Title: Influence Of Internal Factors In Construction Organizations On The Implementation Of Integrated Project Delivery Viewed From The Organizational Change Theory
Creator: Rashed, Ahmed
Date: 2022
Description: Integrated Project Delivery (IPD) is an emerging construction project delivery system that is collaborative oriented. It involves the critical...
Show moreIntegrated Project Delivery (IPD) is an emerging construction project delivery system that is collaborative oriented. It involves the critical participants in an early stage of the project timeline. Recently, IPD is becoming increasingly common. Many organizations are interested in contributing to the Architecture, Engineering, and Construction (AEC) industry. No research studies have previously observed and studied the effect of IPD implementation through an organizational change theory lens. The presented research work was designed to explore the role of organizational factors in the implementing first domain, reflecting the organizational level factors, including cultural and economic considerations. In contrast, the second domain focuses on member-level factors, i.e., employee involvement and readiness to change. Together, these domains influence the organization’s intention and adoption to change toward the IPD as a project delivery system. This impact is viewed through the lens of the OCT based on the contributions and theories discussed by various researchers. These researchers are from a variety of disciplines. A data collection survey was developed to gather quantitative data from the industry. Data was collected from N=128 employees from the construction industry. Data analysis was performed through Structure Equation Modeling using Smart PLS 3. Results showed that communication, integration significantly associated IPD implementation. Moreover, involvement and readiness change also positively predicted the implementation of IPD. The empirical result of current study validates all the constructs of the hypothetical model except reward system.
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