Digital Commons Network^™

Digital Badges And Student Motivation In The Undergraduate Chemistry Laboratory, Sarah Hensiek

Open Access Dissertations

Laboratory courses have been the focus of much research and debate in the field of chemistry. One goal for the laboratory that is consistently cited by faculty is student learning of hands-on skills. Despite this, hands-on skills are rarely assessed in practice because to do so is resource intensive. Digital badges allow each individual student to demonstrate their proficiency in a hands-on lab skill while relieving the constraints associated with assessing individual students during a laboratory period. Previously at Purdue, digital badges were developed for the pipet, buret, and volumetric flask. These badges were shown to support student learning of …

An Examination Of Underrepresentation In Florida, Indiana, And Washington, Jaret Hodges

Open Access Dissertations

Black, Latinx, and Native American students are underrepresented in gifted education programs across the United States. This underrepresentation is one way in which the excellence gap manifests in gifted education. In turn, the underlying causes for underrepresentation are debated by scholars. This dissertation examines the issue of underrepresentation through three case studies. In all case studies, a generalized linear mixed model is used as the framework to analyze publicly available data acquired from the associated state departments of education.

The first case study examines underrepresentation in the state of Florida. In this study, the influence of socioeconomic status on rates …

A Spectroscopic Study Of The Folding Propensities Of Molecules Relevant In Combustion Processes, Daniel Malcolm Hewett

Open Access Dissertations

This thesis focuses on the conformational preferences of molecules relevant in combustion, specifically alkylbenzenes, present in diesel fuels, and covalently-bound naphthalene dimers, likely intermediates in the soot formation process. Utilizing a suite of conformation-specific laser techniques, coupled with a supersonic jet expansion to cool the molecules down to their ground state zero-point vibrational level, the infrared and ultraviolet spectra of individual conformers are collected and compared to theoretical predictions, resulting in conformational assignments.

The first section of this thesis discusses a series of straight chain alkylbenzenes, from ethylbenzene through dodecylbenzene, with the primary goal of determining the shortest chain length …

The Regulatory Role Of Isopentenyl Phosphate Kinase In Plants And The Evolution Of Terpenoid Diversity In Lamiaceae, Laura K. Henry

Open Access Dissertations

Chapter 1 of this dissertation provides background information into the two plant terpenoid biosynthetic pathways, the mevalonate (MVA) and 2-C-methyl-D-erythritol 4-phosphate (MEP) pathways. These pathways are responsible for the formation of the five-carbon building blocks isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP). These metabolites are then condensed to form various chains of C5x terpenoids. The diversity of terpenoids within the diverse Lamiaceae is also discussed.

Chapter 2 looks at the role of a homolog of the archeal gene isopentenyl phosphate kinase (IPK) in plants. IPK is found in all sequenced plant genomes and acts in parallel with the canonical MVA …

Limiting Mixed Hodge Theory And Nonabelian Hodge Theory For Nodal Curves, Feng Hao

Open Access Dissertations

This thesis contains two parts. In the first part, we will give the Deligne 1-motives up to isogeny corresponding to the Q-limit mixed Hodge structures of semi-stable degenerations of curves, using logarithmic structures and Steenbrink’s cohomological mixed Hodge complexes associated to semi-stable degenerations of curves. In the second part, we study the nonableian Hodge theory for nodal curves, construct a “Dolbeault moduli spaces” MDol(X,m) for Higgs bundles on nodal curves, and give the formality theorem for local systems and Higgs bundles on nodal curves. We also give some discussions on the Hitchin fibration of MDol(X,m) and the mixed Hodge structure …

Quantification Of Morphogen Gradients And Patterning Scale Invariance Along Dorsal-Ventral Embryonic Axis, Yan Huang

Open Access Dissertations

Morphogen gradients provide positional information to underlying cells that translate the information into differential gene expression and eventually different cell fates. Scale invariance is the property where the gradients of the morphogen adjust proportionately to the size of the domain. Scale invariance of morphogen gradients or patterns of differentiation is a common phenomenon observed between individuals within the same species and between homologous tissues or structures in different species. To determine whether a pattern is scale invariant, we and others developed definitions and measurements of gradient scaling. These include point-wise and global scaling errors as well as global scaling power. …

Pathways To Persistence: A Study Of The Effects Of Neighborhood Stress And Family Communication Patterns On Community College Student Outcomes, Jill Marie Inderstrodt

Open Access Dissertations

This dissertation draws upon literature from family communication, sociology, public health, and education to determine what neighborhood and family factors contribute to a community college student’s commitment to the goal of completing college. Community college students are more likely to come from low socioeconomic conditions, are more likely to have parents who did not earn a college degree, and are more likely to be ethnic or racial minorities than traditional four-year college students. Because of these demographics, community college students are also more likely to live in neighborhoods with high levels of neighborhood stress: noise and other pollution, crime, high …

Resource Allocation In Nanocommunication Networks And Online Service Platforms., Wei-Kang Hsu

Open Access Dissertations

Resource allocation appears in various forms in communication and networking systems. In this thesis, we start with relay-based nanonetwork communications and analyze the message delay with bacteria-inspired message transfer carriers. Modeling the message transfer as a renewal process, we draw the connection to the mobility model of ad-hoc networks and show that the expected message delay between two nodes is a convex function of the number of available carriers. We then design a decentralized carrier-allocation strategy such that the systematic message delay is minimized. We show that the proposed policy can effectively reduce weighted delays when different message priorities are …

The Alien Eye: Chinese Self-Images And The External Observer, 1874–1911, Yingying Huang

Open Access Dissertations

This dissertation is a literary study of how and why late Qing Chinese self-image formation involved the “alien eye,” by which I mean the view of the foreigner observing and writing about China. I investigate writings and occasionally images produced within the period from 1874 to 1911, framed by the founding of the first Chinese-owned modern newspaper and the overthrow of the Qing empire. The literary genres I address include essays, short stories, novels, and plays. While effects of foreign views of China on the Chinese varied from positive stimulation to psychological damage, I argue that Chinese’ appropriation of the …

Makerspaces For Education, Avneet Hira

Open Access Dissertations

In my dissertation, I present research examining Makerspaces for education. The concept of a Makerspace has evolved, currently being understood as a space for people to practice the idiomatic term Making, which is to tinker or fabricate. Broadly put, Makerspaces are environments where individuals use technologies to Make physical artifacts within a community of fellow Makers.

When I started this work, stakeholders from a variety of backgrounds had begun to discern the educational potential of Makerspaces. Since then, several resources in schools, libraries, educational research, and community spaces have been directed towards realizing this educational potential. However, despite the belief …

Performance Of Finned Heat Exchangers After Air-Side Fouling And Cleaning, Harshad V. Inamdar

Open Access Dissertations

Air-side fouling of enhanced surface heat exchangers by particulate matter may significantly reduce their performance. Hence, the effect of particulate fouling and subsequent cleaning on the performance of finned heat exchangers is investigated. It is anticipated that heat exchanger geometry and operating conditions such as air velocity, air humidity, and concentration of dust in air will impact the process of fouling and subsequent performance degradation of heat exchangers.

In the experimental phase of research, heat exchangers being tested are installed in a wind tunnel where all air-side parameters can be controlled. ASHRAE standard test dust is injected into the air …

A Deuterium-Deuterium Neutron Generator-Based Neutron Capture Therapy System For Brain Tumors, Mindy Hsieh Joo

Open Access Dissertations

Boron neutron capture therapy (BNCT) is an attractive radiotherapy modality that utilizes high-LET particles to deliver the radiation dose. Different from conventional treatments, BNCT has the ability to target tumor cells by injecting patients with a boron10 (B-10) compound that selectively accumulates inside the tumor and irradiating the target area with a neutron beam. The radiation dose produced is very localized due to the short travel range of the resulting particles and limited to the B-10 containing cells. The surrounding healthy tissues receive minimal dose. At present, the BNCT neutron sources are mainly nuclear reactors and large particle accelerators. These …

Constructing Fragment-Density Functionals, Kaili Jiang

Open Access Dissertations

Approximations of the non-additive non-interacting kinetic energy (NAKE) as an explicit functional of the density are the basis of fragment-based methods that provide improved computational efficiency over standard Kohn-Sham calculations. However, within most fragment-based formalisms, there is no unique NAKE, making it difficult to develop general, robust approximations to it. In partition density-functional theory (P-DFT), the ambiguity of the NAKE is removed and approximate functionals may be more meaningfully compared to exact quantities. We demonstrate that the decomposable approximations constructed from approximations to the non-interacting kinetic energy fail to reproduce accurate NAKE and discuss promising avenues for constructing fragment density-functionals …

Final Causality In The Thought Of Thomas Aquinas, Joel Johnson

Open Access Dissertations

Throughout his corpus, Thomas Aquinas develops an account of final causality that is both philosophically nuanced and interesting. The aim of my dissertation is to provide a systematic reconstruction of this account of final causality, one that clarifies its motivation and appeal. The body of my dissertation consists of four chapters. In Chapter 1, I examine the metaphysical underpinnings of Aquinas’s account of final causality by focusing on how Aquinas understands the causality of the final cause. I argue that Aquinas holds that an end is a cause because it is the determinate effect toward which an agent’s action is …

Part I. The Rational Design, Synthesis And Evaluation Of Second Generation Class Ii Hmg-Coa Reductase Inhibitors Part Ii. Studies Directed Toward The On-Resin Preparation Of C-Terminal Modified And Cyclic Peptides, Matthew A. Hostetler

Open Access Dissertations

The first part of this dissertation involves the rational design, synthesis and biological evaluation of small molecules targeting Class II HMGR. Inhibitors of this generation were designed based on information derived from the crystal structures of first generation analogues complexed in the active site of E. faecalis HMGR. On the basis of this information, polar functional groups were installed to engage specific active site residues. Of the second generation analogue set, two compounds were found to possess improved enzymatic inhibition compared to that of the most biologically active first generation analogue. Additionally, these two analogues were found to inhibit penicillin …

Revisiting The Decay Of Monochloramine, Utami Irawati

Open Access Dissertations

An aqueous solution containing predominantly monochloramine can be very complex chemically, as once it is formed, monochloramine can undergo a number of reactions. The loss of monochloramine primarily occurs through monochloramine hydrolysis or through a disproportionation reaction. However, there are only a few research papers that have investigated the kinetics of these two reactions. Some of the findings of these previous studies show inconsistencies with respect to the rate constant values of the reactions. Hence, both of these reactions were studied in depth in this work. In the case of the disproportion-ation reaction, previous studies have indicated that the presence …

A Multi-Agent Control Approach For Optimization Of Central Cooling Plants, Rita Jaramillo

Open Access Dissertations

This research focuses on the application of a multi-agent control approach to optimal supervisory control of central cooling systems. Most of the research related to supervisory control of central cooling systems has focused on centralized control approaches. Although these approaches can be effective at reducing operational costs, the high initial costs associated with site-specific controller design and implementation, and the need to update the plant model and control sequences every time a modification is made, have prevented a greater penetration of these technologies in the market. In light of these limitations, the goal of this research is the development and …

Essays On Labor Economics, Xuan Jiang

Open Access Dissertations

Quantum annealing (QA) uses the principles of quantum mechanics for solving unconstrained optimization problems. Since its initial proposal, there has been much interest in the search for practical problems for which QA has advantage over classical algorithms. Although it is believed that quantum computers cannot in general solve NP-complete problems effciently, there has been evidence suggesting that effects such as quantum tunneling can bring quantum speedup over classical computation for some problems in NP.

In this dissertation, we consider two problems that have both theoretical and practical importance. One is the Set Cover with Pairs problem. The other is the …

Quantum Annealing For Solving Optimization Problems, Shuxian Jiang

Open Access Dissertations

Quantum annealing (QA) uses the principles of quantum mechanics for solving unconstrained optimization problems. Since its initial proposal, there has been much interest in the search for practical problems for which QA has advantage over classical algorithms. Although it is believed that quantum computers cannot in general solve NP-complete problems efficiently, there has been evidence suggesting that effects such as quantum tunneling can bring quantum speedup over classical computation for some problems in NP. In this dissertation, we consider two problems that have both theoretical and practical importance. One is the Set Cover with Pairs problem. The other is the …

Early Social Origins Of Premature Aging: How Do Childhood Exposures Shape Aging And Mortality?, Blakelee R. Kemp

Open Access Dissertations

The early origins of health literature documents a distinct link between early life exposures and a range of pathologies in later life. However, it is still unclear if and which types of childhood events and experiences shape biological aging or increase mortality risk among older adults. The purpose of this dissertation is to examine (1) what types of early life exposures influence biological aging and mortality and for whom and (2) whether biological age acts as a marker of early life stress and a predictor of mortality. Drawing from cumulative inequality theory, this dissertation uses six waves of data (2004-2014) …

Agent-Based Approach For System Identification And Optimal Control Of High Performance Buildings, Jaewan Joe

Open Access Dissertations

Commercial buildings have strong impacts on humans and the environment. They not only affect occupants’ comfort, health, and well-being but also consume more than 19% of the total energy consumption in the US. High performance building designs can achieve significant energy savings, with new building technologies such as advanced building envelopes, thermally activated building systems, on-site power production and thermal storage; dynamic effects related to variability in occupancy and environmental conditions; diversity in occupant thermal preferences; and the integration of these diverse technologies into an overall control system design. Model-based predictive control (MPC) is a promising approach for the realization …

Assessment Of Dcnet: A New Data Center Network Architecture, Rajas H. Karandikar

Open Access Dissertations

Migration of enterprise computation and storage to cloud data centers has imposed new communication requirements and a need for fundamental changes in infrastructure. As more applications are hosted inside virtual machines and containers in the cloud, a significant amount of networking occurs within data centers, increasing the so-called east-west communication. With the increasing use of virtual machines and their migration across physical servers, future data centers must support efficient mobility in addition to traditional requirements of scalability and easy manageability. This dissertation proposes and analyzes a radical redesign of data center networks, using a new approach called DCnet. DCnet changes …

Dissection Of Genetic Variation In Maize Underlying Photosynthetic Traits, Rajdeep Singh Khangura

Open Access Dissertations

Forward genetics has been vital in revealing the identity and function of most plant genes. However, detecting phenotypically relevant variation outside the coding region of genes and distinguishing it from neutral changes is not trivial. One way to facilitate this is by employing genetic sensors that reveal even minute variation in the trait. Our lab has designed a novel approach in which the phenotype of a mutant is used as a reporter to identify modifier loci present naturally in the germplasm. It has been dubbed MAGIC, for Mutant-Assisted Gene Identification and Characterization. I used a MAGIC screen in maize to …

“Muthologos Has Lost Such Ground”: Myth, History And Orality In The Poetics Of Charles Olson, Matthew L. Kroll

Open Access Dissertations

American poet Charles Olson (1910-1970) spent the last two decades of his life composing his magnum opus, the three-volume modern verse epic The Maximus Poems (Maximus). He began composing Maximus in 1950, the same year he published his poetics manifesto “Projective Verse.” Taken together, these two moments in Olson’s career can be read as marking the beginning of his mature poetics and poetry. However, the concepts he develops and the projective verse style he proclaims in the first half of the 1950s can already be seen emerging in his earlier publications.

Beginning with two of his most significant publications of …

Refracting Gender: Experiences Of Transgender Students In Postsecondary Stem Education., Elizabeth Kersey

Open Access Dissertations

Transgender students are often an invisible minority in postsecondary education, particularly in STEM fields. I am addressing the lack of research in this area with an exploratory narrative study designed to answer two questions: (1) How have the experiences of postsecondary transgender students in STEM education varied with their gender presentation? (2) How do their experiences with mathematics compare with other STEM fields? I conducted a sequence of three interviews each with three participants to gather information about their life histories relating to gender and STEM. This information was then restoried utilizing the three-dimensional space of narrative inquiry proposed by …

Turbulent Heat Transfer In Supercritical Fluids Under Transcritical Temperature Conditions, Kukjin Kim

Open Access Dissertations

Boiling at the ambient pressure undergoes a critical heat flux in the nucleate boiling regime and it determines the thermal efficiency and the applicable range of heat flux (low/moderate heat flux, <105 W/m2; high heat flux, 2.5×105–107 W/m2; ultrahigh heat flux, 107–109 W/m2). Since the regime beyond the critical heat flux shows a significant reduction in the overall achievable heat transfer rate, it is a reference for efficient heat transfer. We propose to investigate supercritical fluids to overcome such a limit. A supercritical state is reached when the fluid is at temperatures and pressures exceeding its critical point. The supercritical fluid has simultaneously a liquid-like density and gas-like diffusivity, without a distinctive phasechange or surface tension, with the potential of overcoming deleterious effects and limitations of classical boiling. In this study, we have performed direct numerical simulations solving the compressible Naview–Stokes equations for natural (R-134a, carbon dioxide, and methanol) and forced (R-134a) convection in transcritical temperature ranges in order to investigate and discuss the phenomena of pseudophase change with a specific focus on the heat transfer and turbulence structures/dynamics using structural and statistical approaches. In natural convection pseudoboiling at supercritical pressure in transcritical temperature ranges (ΔT =1 K, 5K,20K, and40KwhereΔT is bottom-to-top temperature difference), increasing ΔT leads to the higher recirculation frequencies, enhancement of heat transfer, and breakup of global circulating motion. Two-dimensional simulations have limitations to proper prediction of the flow dynamics and heat flux compared to three-dimensional ones. The proposed heat transfer correlation explains the natural convection pseudoboiling well, yet not perfectly. The real fluid effects cause the large thermodynamic gradients at the pseudotransition interface and increasing ΔT requires finer grid resolution due to unresolved length scales. Turbulent forced convection is studied with ΔT = 5 K, 10 K, and 20 K (Ttop/bot = Tpb ± ΔT/2). At these conditions, a pseudophase change occurs at various wall-normal locations within the turbulent channel from ypb/h = −0.23 (ΔT = 5 K) to 0.89 (ΔT = 20 K), where h is the channel half-height and y = 0 the centerplane position. Increases in ΔT also result in increasing wall-normal gradients in the semi-local friction Reynolds number. Classical, compressible scaling laws of the mean velocity profile are unable to fully collapse real fluid effects in this flow. The proximity to the pseudotransitioning layer inhibits the turbulent velocity fluctuations, while enhancing the temperature and density fluctuations. The latter reach peak values (relative to their mean) comparable to what is observed in a M =3.0 ideal gas isothermal-wall compressible turbulent channel flow. Conditional probability analysis reveals that the sheet of fluid undergoing pseudophase change is characterized by a dramatic reduction in the kurtosis of density fluctuations, hence becoming thinner as ΔT is increased. Instantaneous visualizations show dense fluid ejections from the pseudoliquid viscous sublayer, some reaching the channel core, causing positive values of density skewness in the respective buffer layer region (vice versa for the top wall) and an impoverishment of the turbulent flow structure population near pseudotransitioning conditions.

Understanding Autism Spectrum Disorder Through A Cultural Lens: Perspectives, Stigma, And Cultural Values Among Asians, Ankita Krishnan

Open Access Dissertations

Autism spectrum disorder (ASD) is a neurodevelopmental disorder that has become increasingly prevalent in cross-cultural literature. Despite the well-supported finding that culture informs perceptions, belief patterns, values, there is little research illuminating this association or the fundamental role of culture for understanding ASD as a whole. The present study investigated the relationships among knowledge of ASD, stigma related to ASD, and cultural values among self-identified Asian individuals living in the United States (N= 373). Exploratory structural equation modeling (ESEM) was used to examine model fit of ASD knowledge assessment and cultural values in this sample, as well as to investigate …

Kinematics And Dynamics Of The Pamir, Central Asia And Main Ethiopian Rift, Cassidy N. Jay Seymour

Open Access Dissertations

Plate tectonic theory predicts that deformation is localized in narrow zones along plate boundaries, but geodetic, seismic, and geological observations show that deformation of continents is diffuse and complex. Furthermore, dense, recently published GPS velocities hint at regional heterogeneities within two of the most widely studied continental deformation zones in the world: the India-Eurasia collision zone and East African Rift System. Here, we use numerical models to investigate deformation in the Pamir, a region west of the Tibetan Plateau, and the Main Ethiopian Rift, the northernmost segment of the East African Rift System. Inverse and forward numerical models are constrained …

To Give Or To Act? The Transition Of Ngos From Aid Donors To Human Rights Advocates, Junhyup Kim

Open Access Dissertations

Non-governmental organizations (NGOs) have become increasingly important as a political group of actors in international politics since the 1990s. Above all, the NGOs engaging in economic aid have greatly contributed to foreign aid to developing countries. The significance of this study is placed on the transition of NGOs from aid providers to human rights advocates. The transition to human rights advocates signifies that charity organizations have now become a major form of political actor. The research question is why some aid NGOs engage in human rights issues, while others do not. I argue that contact with human rights norms is …

Atomistic Simulations And Microscopic Experiments To Understand Nanoscale Composition Control, Changeun Kim

Open Access Dissertations

In this dissertation, the possibility of using the quantum mechanics calculation in combination with experimental result is explored, in order to explain experimentally observed phenomena in materials science problems. A series of published works in this theory-experiment combinatory approach will be introduced. The topics include the phase stability of Sb2O4, surface instability of MgB2, the interplay of diffusion and mechanical strengthening effect in multilayer, and latest findings of the syntheses of metallic nano-foams. The theory-experiment combinatory approach has proven to be useful in various materials science problems. The phase transformation trajectory of the Sb2O4 polymorphs, the surface reconstruction pathways of …