Digital Commons Network^™

Automated Hardwood Lumber Grading, Logan Wells

Open Access Theses

Grading lumber is a process of assigning a quality measurement and thus dollar value to individual boards. Throughout the entire hardwood manufacturing process and individual board can be graded multiple times from when the board is first sawn from the log, before and after drying and when it reaches the end manufacturer. For hardwood lumber both appearance and structural soundness factor into the grade of a board. The National Hardwood Lumber Association (NHLA) was created to establish a uniform standard for grading hardwood lumber. Many companies still have proprietary grades specific to their business, but the vast majority of hardwood …

Optimized Angles Of The Swing Hyperspectral Imaging Tower For Single Corn Plant, Libo Zhang

Open Access Theses

During recent years, hyperspectral imaging systems have been widely applied in the greenhouses for plant phenotyping purposes. Current imaging systems are mostly designed as either top view or side view imaging mode. Top-view is an ideal imaging angle for top leaves which are often more flat with more uniform reflectance. However, most bottom leaves are either blocked or shaded from top view. From side view, most leaves are viewable, and the entire structure can be imaged. However, at this angle most of the leaves are not facing the camera, which will impact the measurement quality. At the same time, there …

Can U.S. Agriculture Provide Agro-Pharms For Malaria Treatment?, Chong Zhao

Open Access Theses

For policy analysis, interest is in investigating the effect of a subsidy policy-switching regime on agro-pharms investment through the theory of investment under uncertainty. It considers the probability of a policy implemented when it is not in effect and the probability of removal when it is in effect. Poisson type policy jumps models a discrete subsidy policy, which provides pharmaceutical plants financial assistance to manufacture Artemisinin-based therapies. A case study analysis determines if Artemisinin efficiency improvements can result in the development of a commercially viable U.S. agribusiness investment opportunity. Accounting for uncertainty, irreversibility, and adoption timing in establishing an Artemisinin …

She Is A Computer Scientist: A Quantitative Comparison Between The Effectiveness Of Game Design Studios And Robotics At Enhancing Women's Learning Of, Self-Efficacy In, Attitudes Toward, And Domain Identification With Computer Science, Ali Nazil Alshammari

Open Access Dissertations

The underrepresentation of women in computer science is a serious issue with ramifications that affect not only women working in the field, but also the field at large and the national economy. While the problem is attributed to several interconnected causes, such as computer knowledge, experience, and familiarity; they do not tell the entire story, nor do they point to a global trend. Studies indicate that these factors did not stop the computer science field from achieving a balanced male-female ratio in non-western countries. Since no single factor can be attributed as the primary cause of this complicated problem, and …

Comparison Of Brachypodium And Wheat Response To Hessian Fly, Abdelrahman Ahmed Abdelhady Mohamed Awad

Open Access Dissertations

Wheat (Triticum aestivum) yield is limited by biotic stresses such as Hessian fly [Mayetiola destructor (Say)] attack which causes a significant annual loss. Previous studies have shown that Brachypodium distachyon is resistant to Hessian fly infestation. Since B. distachyon has advantages over wheat to be used as a model plant in genetic and genomics, we compared the response of 5 wheat lines (4 resistant lines, harboring different Hessian fly-resistance H genes, and 1 susceptible line to Hessian fly infestation) to B. distachyon at early stages [12 hours, 1 day, 3 days and 5 Days After Hessian fly egg-Hatch (DAH)] of …

Avian Immunogenetics And Evolution Of A Passerine Bird In The Face Of Malarial Parasites, Jennifer D. Antonides

Open Access Dissertations

A key goal of evolutionary biology is understanding the complex mechanisms underlying adaptive evolution, and the study of the co-evolution of hosts and parasites is a primary tool. The work in this dissertation involves exploring the evolution of avian immune genes in the context of phylogeny and malarial parasitic infection using next generation sequencing approaches. The bananaquit (Coereba flaveola) is a Caribbean passerine bird and a common host of haemosporidian parasites which cause avian malaria (Plasmodium spp. and Haemoproteus spp.). The genes of a host’s immune system, including those of the Major Histocompatability Complex (MHC) of the adaptive immune system …

Assessment Of Urbanization Impacts On Surface Runoff And Effects Of Green Infrastructure On Hydrology And Water Quality, Jingqiu Chen

Open Access Dissertations

Urbanization is one of the most important anthropogenic modifications of the global environment. It has significant impacts on hydrologic processes and water quantity and quality. Research related to urbanization impacts on surface runoff has focused on changes up to the watershed scale. However, quantitative assessment at a national scale is scarce. Parallel to urbanization impacts, climate is also one of the greatest challenges facing humanity today and its effects are already being felt from strengthened storms and rising sea levels to changing temperature and weather patterns. The adverse impacts of urbanization and climate can converge in synergistic ways, which may …

The Human Dimensions Of Invasive Plant Management On Family Forestlands: A Case Study In Indiana, Mysha K. Clarke

Open Access Dissertations

Invasive plant management is an increasing concern in socio-ecological systems. Ecologically, invasive plants can displace native species, reduce forest health and productivity, and degrade recreational areas. From a socio-economic perspective, the United States spend approximately USD 137 annually in damage and control costs from invasive plants and animals. Despite these impacts, invasive plants continue to spread in forest ecosystems because of various anthropogenic factors like trade, transportation, climate change, and limited regulation in many states. It is pivotal to consider the role of family forest owners (FFOs) in invasive plant management in forest ecosystems because collectively they own 36% of …

Modeling And Simulation Of Blood Flow Past The Distal Anastomosis Of The Arteriovenous Graft For Hemodialysis, Zengding Bai

Open Access Dissertations

Hemodialysis is a common treatment for ESRD patients to manage their chronic renal failure while awaiting kidney transplant. Arteriovenous graft is a major vascular access for hemodialysis but often fails due to the thrombosis close to the anastomosis. Most of existing computational models employ an unrealistic rigid model assuming the vein and graft are rigid. And some of the existing results are inconsistent in characterizing the flow and force fields. We introduce a new three-dimensional computational model that incorporates the vein and graft deformability. The new model is based on the lattice Boltzmann-immersed boundary (LB-IB) framework for handling the fluid-flexible-structure …

Gender And Parental Support To Adult Children In Later Life, Gülçin Con

Open Access Dissertations

Background and Objectives: Past research has examined gender differences between mothers’ and fathers’ ties with their adult children; however, the interdependency between mothering and fathering for adult children was left unexamined. This study addresses this gap by examining the extent to and ways in which parental support to adult children in later life is initiated and negotiated among married couples, and whether these patterns reflect the gendered patterns and practices found in parental involvement earlier in the life course. Research Design and Methods: I conducted in-depth in-person interviews with 34 parents on their ties with each of their adult children. …

Label Free Chemical Imaging Reveals Novel Metabolite Signatures In Living Model Organisms, Jing (Andy) Chen

Open Access Dissertations

Cell and molecular biology often need direct monitoring of the dynamic distribution and interactions of metabolites in living cells and model organisms. However, this task is extremely challenging for a few reasons. Labeling metabolites with markers can potentially interrupt the dynamic cellular events that are aimed to be observed. Moreover, labeling dyes are usually toxic to cells. Lastly, many labeling methods require cell fixation thus cannot be used to study cellular dynamics. Label-free chemical imaging methods such as stimulated Raman scattering (SRS) circumvent these problems by generating signals based on the intrinsic optical property of target biological metabolites. As a …

Acute Effects Of Contractile Activity On Skeletal Muscle Exosomes, Ron T. Garner

Open Access Dissertations

Introduction: Skeletal muscle functions as an endocrine organ, and a key way to accomplish that is through exosomes. The internal budding of a multivesicular body (MVB) forms exosomes and contains mRNA, miRNA, and proteins. Through a multifaceted approach, the following three experiments were designed to better understand the effect of contractile activity on skeletal muscle MVB/exosome biogenesis and release.

Study 1: Exosome-related pathway response to acute exercise. Sedentary, lean, healthy male subjects (n=12) performed 45 min cycling (AEx), followed by single leg knee extensor exercise (A+REx). A biopsy was obtained prior to exercise and 1 hr post-exercise from each leg. …

Understanding The Adoption, Maintenance, Diffusion Of Urban Stormwater Management Practices, Yuling Gao

Open Access Dissertations

Urbanization increases stormwater volume and decreases infiltration capacity due to the impact of added impervious surfaces and reduced vegetation. Urban stormwater management practices (SMPs) employ control and treatment measures to mitigate water runoff and break down pollutants using a natural approach, which has proven to be effectively protecting the hydrological process of streams. Though a significant number of empirical studies identified the effectiveness of urban SMPs, a few studies have investigated individuals’ perceptions about the approach and factors that influence decision-making on its implementation. This dissertation is intended to investigate the adoption, maintenance, and diffusion of urban SMPs through mail …

Enzymatic Inhibition By Lignin During Second Generation Ethanol Production, Antonio Carlos Freitas Dos Santos

Open Access Dissertations

An important hindrance to commercialization of lignocellulosic ethanol is the high cost of enzymes. Reducing enzyme loadings is necessary to reduce costs. Knowledge of the inhibitors of these enzymes is necessary to better inform enzyme development and process design. Five factors have been identified: soluble inhibitors, solid lignin adsorption, product inhibition, mixing efficiency and oxygen deactivation of the enzymes that hydrolyze cellulose to glucose. These factors are intertwined and properly assessing them individually require the elimination of the others. Isolating each factor, however, has not been done throughout literature leading to lumped constants. Soluble inhibitors reduce conversion sharply leading to …

Polysulfide Mitigation At The Electrode-Electrolyte Interface: Experiments In Rechargeable Lithium Sulfur Batteries, Arthur D. Dysart

Open Access Dissertations

In the field of energy storage technology, the lithium sulfur battery is intensely studied in interest of its great theoretical gravimetric capacity (1672 Ah kg–1) and gravimetric density (2600 Wh kg–1). The theoretical performance values satisfy viability thresholds for petroleum–free electric vehicles and other emerging technologies. However, this elusive technology remains in the research sector due to a wealth of challenges resulting from its complex chalcogenide electrochemistry. The most infamous challenge remains the polysulfide redox shuttle, a phenomenon in which lithium polysulfide intermediates are produced as elemental sulfur S8 is reduced to lithium sulfide Li2S during the discharge cycle. Because …

Soundscape Ecology: Rich Contexts For Investigating Conservation Biology & The Effect Of Informal Environmental Experiences On Youth’S Conceptual Understanding, Interest And Identity Development, Maryam Ghadiri Khanaposhtani

Open Access Dissertations

Recent educational studies have shown increasing lack of interest and participation of youth (ages 10-14 years old) in various STEM (Science, Technology, Engineering and Mathematics) fields in the U.S. The decline in the number of youth choosing to study STEM fields in higher education and the resulting lack of STEM professionals in the society has drastic economic impacts. Therefore, it is critical to introduce youth to quality STEM education that engages them with science practices and triggers their interest and curiosity in order to increase their participation in those fields. To address this issue, the aim of this study is …

Lipid And Metabolite Profiling Mass Spectrometry Of Human Glioblastoma Using Mouse Xenograft Model, Soo Jung Ha

Open Access Dissertations

Glioblastoma (GBM) is the most common and malignant form of human primary brain tumor. Due to its extremely malignant and invasive nature, the mean survival period of GBM patients is only 12 to 15 months from diagnosis. GBM patients rely on current treatment options including surgery, radiation and chemotherapy. Unfortunately, these treatment options fail to improve quality of patients’ lives. Studies have shown that altered lipids and metabolites in GBM may play a critical role in chemo-resistance, cancer cell initiation and progression regulated by oncogenic signaling pathways. This research utilized multiple reaction monitoring (MRM) profiling mass spectrometry (MS) and desorption …

Characterizing Trade-Off Decisions In Student Designers, Molly Hathaway Goldstein

Open Access Dissertations

Decision-making and design in uncertain situations in which information is limited and goals are ambitious or conflicting are a part of common practices of engineers. Such abilities in engineering practices are important to develop for all students from elementary school through college and graduate school. An important aspect of decision-making in design are the trade-offs decisions designers make throughout a project. Trade-offs are a complex element of a decision, that involves weighing possible outcomes against their respective benefits and costs in areas such as aesthetics, cost, degree of safety, and various performance indicators. Making trade-off decisions is an effective design …

Gas-Phase And Condensed-Phase Studies Of Small Reactive Intermediates, Christopher William Haskins

Open Access Dissertations

Nitriles are an integral functional group in many chemical industries. A new methodology for the dehydration of amides to nitriles has been developed using a palladium catalyst. The reaction conditions are robust and able to tolerate a wide variety of functional groups and substrates. The substrate scope can be broken into 4 main types of substrates including: alkyl, aromatic, cinnamic, and α, β, δ, γ-unsaturated amides. Mechanistically, the amide goes through a water exchanging mechanism to generate acetamide in equal parts to the nitrile. Cyclopropanols are important precursors for the generation of beta-carbonyl radicals. In the presence of a single-electron …

Native Graph Support In Relational Data Systems, Mohamed S. Hassan

Open Access Dissertations

A variety of data management applications spanning various domains, e.g., social networks, transportation, and bioinformatics, have graphs as first-class citizens. Specialized graph databases can serve these applications to evaluate vital graph-traversal queries, e.g., shortest path and reachability queries. However, specialized graph databases are not as mature as the pervasive relational database systems. Although the literature has several proposals to process graph queries inside an RDBMS, none of these proposals process graphs natively inside an RDBMS for potentially better performance, which is particularly challenging due to the impedance mismatch between the relational and the graph models. Additionally, to scale for large …

Effects Of Per/Polyfluoroalkyl Substances On Larval Amphibians, Gary M. Hoover

Open Access Dissertations

Per/polyfluoroalkyl substances (PFAS) are a group of persistent organic pollutants of emerging concern. Widespread use, along with volatility of some PFAS, has led to global distribution in soils and surface waters. The chemical stability of these compounds assures persistence in the environment, with effects unknown to much of the chronically-exposed biota. Many toxicology studies implicate PFAS in disruption of the hypothalamus-pituitary-thyroid (HPT) axis, which is known to play a major role in control of metamorphosis in amphibians. Thus, amphibians represent a class of organisms that may be susceptible to sub-lethal effects of PFAS exposure.

Three main aims were accomplished to …

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 …

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 …

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 …

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 …

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 …