Digital Commons Network^™

Goosegrass Biology, Genetic Diversity And Innovative Control Measures, Robert Kerr

All Dissertations

Goosegrass (Eleusine indica (L.) Gaertn.), a C4 grass found in most areas of the world, is one of the most troublesome weeds in tropical and temperate environments. Turfgrass systems are intensely managed and frequently used for a number of different sporting pursuits. Due to high traffic, these areas become compacted and maintaining a healthy sward of dense turfgrass can be challenging, as a result these areas can become infested with weeds such as goosegrass. Understanding a weeds life cycle and biology is fundamental in developing control strategies. Three main areas of interest in regards to goosegrass biology and control …

Investigating Inequality: Peer Effects And Occupational Licensing, Bobby (Wing Yin) Chung

All Dissertations

This dissertation discusses the role of social network and labor market regulation in understanding racial and gender inequality. The first chapter contributes to the discussion on childhood exposure by investigating the extent to which the educational background of peers' parents is related to a child's future college attainment. I analyze the friendship networks of a nationally representative sample of high-school students in the US and find that the spillover from peers' parents of the same gender operates independently of peers' academic performance. The effects are robust in addressing friendship selection. The same gender pattern suggests either the transmission of gender …

Measuring The Adaptability Of University Campus Buildings Using The Analytic Hierarchy Process, Anna Kathleen Becker

All Theses

While adaptable building design is an area of increasing interest, there are few studies with quantitative empirical data regarding which physical characteristics of buildings are most effective at facilitating adaptation. Additionally, of the few adaptability evaluation tools that focus on characteristics of physical design, little has been done by way of validation. The primary purpose of the current thesis was to evaluate the relative importance of physical design characteristics to the adaptability of buildings (the ease with which buildings can be physically modified, deconstructed, refurbished, reconfigured, or repurposed) (Ross et al. 2016). For the purpose of this thesis research, characteristics …

Improvements To Mle Algorithm For Localizing Radiation Sources With A Distributed Detector Network, Guthrie Cordone

All Theses

Maximum Likelihood Estimation (MLE) is a widely used method for the localization of radiation sources using distributed detector networks. While robust, MLE is computationally intensive, requiring an exhaustive search over parameter space. To mitigate the computational load of MLE, many techniques have been presented, including iterative and multi-resolution methods.

In this work, we present two ways to improve the MLE localization of radiation sources. First, we present a method to mitigate the pitfalls of a standard multi-resolution algorithm. Our method expands the search region of each layer before performing the MLE search. Doing so allows the multi-resolution algorithm to correct …

Human Powered Energy Harvester Based On Autowinder Mechanism: Analysis, Build And Test, Abby Joseph Arakal George

All Theses

Experts estimate that approximately one third of the worldwide population currently owns a smartphone, and subscriptions continue to grow. Compared to mobile devices of the past decade, smartphones provide desktop computer-level processing power in a palm-sized package. However, the high computing power and 24 hours - 7 days a week connectivity results in a shorter battery life, often forcing the user to rely on portable battery packs. Worldwide energy consumption statistics show that the electric power grid depends primarily on fossil fuels. Thus, a renewable power source based on human motion energy harvesting offers a potential solution to power portable …

Implicit Stereotypes: An Explanation For The Lack Of Female Leadership In The Stem Fields?, Katherine N. Brown

All Theses

The purpose of this study was to investigate why there is a lack of female leadership in the STEM fields. Literature shows that there are a variety of gender stereotypes that may be an impediment to women seeking leadership roles in the STEM fields. The present study combined information about gender stereotypes regarding leadership ability and gender stereotypes regarding math and reasoning ability in attempt to explain the lack of female participation and leadership in the STEM fields. An implicit association test (IAT) was administered to measure implicit gender stereotypes about leadership, and IAT scores had the expected positive relationships …

On The Edge Of The World: Examining Pro-Environmental Outcomes Of Last Chance Tourism In Kaktovik, Alaska, Lauren Miller

All Theses

Travel to impact-sensitive destinations has been on the rise in recent years. Coined last chance tourism (LCT), visitors are flocking to these imperiled destinations to see them before they are gone. To off-set their presence, which ultimately contributes to site degradation, a possible positive outcome of these LCT experiences is the creation of environmental ambassadors. Utilizing data collected from 189 visitor surveys, the purpose of this study is to provide a basis for understanding the visitor experience and outcomes of boat-based polar bear viewing in the Kaktovik area of the Arctic National Wildlife Refuge. This study contributes to current literature …

Modelling Strategies To Examine The Influence Of Fidelity Levels On Dynamic Behavior Of Multi-Mw Wind Turbine Gearbox, Jesalkumar Thakkar

All Theses

With the increasing concerns about atmospheric complications, for example global warming from ozone layer depletion, the world is currently experiencing a shift from conventional resources to renewable sources of energy. Presently, wind is one of the cleanest and fastest rising energy sources and has been in growing demand. The wind turbine industry faces problems related to immature failure of wind turbine gearboxes. In most cases, these failures are traced back to gears and bearing malfunctions, such as gear micro-pitting and bearing skidding. Previous studies suggest that transmission of transverse and bending loads from the rotor to the gearbox can result …

Analytical Modeling Of Melting Of Levitated Ice Particles And Freezing Of Water Films On Cold Surfaces, Shivuday Kala

All Theses

Aircraft engine icing has emerged as one of the greatest threats to safe operation of aircrafts today contributing to more than half of all the aircraft icing accidents reported between 1990-2000. Engine icing mostly occurs in the low-pressure compressor section of the engine where ice particles entering the engine undergo partial or complete melting on encountering warm surfaces. These partially melted crystals cool the engine parts until the freezing point of water is reached. Further accumulation of ice inside the engine leads to ice accretion and shedding. This situation may lead to complete power loss in the engine and acts …

Adaptation To Varying Latency In A Head-Mounted Display, Sarah Christine Beadle

All Theses

The purpose of this study was to examine if individuals could adapt to varying latency in a head-mounted display (HMD) through repeated exposure. Simulator sickness has been a pervasive problem as HMDs grow in popularity. Recent work by Kinsella (2018) showed that people can adapt to latency in an HMD, but it remained unknown if they can adapt to latency that varies in frequency and amplitude. Following recommendations in the literature, participants experienced three exposures separated by 48 hours of either constant or variable latency. The three sessions were the same length, with participants performing the same task, separated by …

Size Effects In Periodic Lattice Structured Cellular Materials, Marcus J. Yoder

All Dissertations

When the material properties of cellular materials are tested, small samples may have different apparent material properties than large samples. This difference is known as a size effect. This work examines size effects in periodic thin walled cellular materials using a discrete beam element lattice model.

Chapter 2 uses this lattice model to characterize size effects for a variety of lattice topologies and boundary conditions. It also compares those size effects to results coming from a nominally equivalent micropolar model. Micropolar elasticity extends classical elasticity to incorporate size dependent behaviors and can therefore capture size effects in a continuum model. …

Reliability In A Dynamic Stochastic Environment, John Charles Nicholson

All Theses

Consider a device or structure whose lifetime under perfect conditions follows a distribution determined by a hazard function. In a perfect world, the distribution of the device is already known, but suppose environmental conditions are imposed. We consider a model where the device is subjected to a series of shocks that are determined by a point process, but allow for the shocks to leave a residual effect as time goes on. Furthermore, we would also allow for the hazard function to have an effect on the intensity function of the point process. We are interested in the effects of this …

The Calkin-Wilf Tree And Its Various Properties, Catherine Mary Kenyon

All Theses

The Tree of All Fractions, otherwise known as the Calkin-Wilf tree, gets its name from the fact that every reduced positive rational appears once in this binary search tree. We look at the various properties this tree is known to hold and will explore a plethora of related, yet new, characteristics within the patterns of the tree.

One of the most interesting properties of the tree we will state is the numerators are the hyperbinary representation of that index in the sequence, as already observed by Calkin and Wilf. We will take look at this as well as the ordering …

A Mixed Methods Approach For Improving The Radiation Safety Climate At Princeton University, Caitlin Marie Root

All Theses

Various techniques were implemented at Princeton University in an effort to improve the safety climate associated with open-source radioactive material use. The initial and post-intervention safety climate of those working in radiation laboratories was assessed by fielding surveys and conducting behavioral observations. Baseline results of assessed safety climate categories indicated safety practices and safety compliance were in the most in need of improvement. Specific training based on these results was provided to laboratory members, and creative signage and a safety newsletter were posted in and around laboratories for reinforcement. Signage posted utilized pop cultural memes and other engaging graphics, designed …

Development Of A Novel, Tree-Like Branching Continuum Robot With Variable Topology, Michael Clayton Lastinger

All Theses

This thesis describes the design and physical realization of a novel branching continuum robot, aimed at inspection and cleaning operations in hard-to-reach environments at depths greater than human arm lengths. The design, based on a hybrid concentric-tube/tendon actuated continuum trunk core, features two pairs of fully retractable continuum branches. The retractable nature of the branches allows the robot to actively change its topology, allowing it to penetrate narrow openings and expand to adaptively engage complex environmental geometries. We detail and discuss the realization of a physical prototype of the design, and its testing in several simulated application environments.

Engineering Design Team Leadership In Undergraduate Design Teams, James Righter

All Dissertations

The objective of this research is to develop an understanding of the emergence and distribution of leadership behaviors in engineering design teams. This research was conducted with undergraduate engineering students and explored leadership behaviors within design teams in a variety of contexts. Undergraduates were selected for the study since they possessed similar education and skills as a novice engineer in industry. A mixed methods approach incorporated qualitative and quantitative techniques including interview, case study, and protocol study instruments. The use of these methods enabled the exploration of leadership in both natural and controlled environments to capitalize on the research advantages …

Approximate Dynamic Programming: Health Care Applications, Amir Ali Nasrollahzadeh

All Dissertations

This dissertation considers different approximate solutions to Markov decision problems formulated within the dynamic programming framework in two health care applications. Dynamic formulations are appropriate for problems which require optimization over time and a variety of settings for different scenarios and policies. This is similar to the situation in a lot of health care applications for which because of the curses of dimensionality, exact solutions do not always exist. Thus, approximate analysis to find near optimal solutions are motivated. To check the quality of approximation, additional evidence such as boundaries, consistency analysis, or asymptotic behavior evaluation are required. Emergency vehicle …

Cm Scale Flapping Wing Of Unmanned Aerial Vehicle At Very Low Reynolds Numbers Regime, Abduljaleel Altememe

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This dissertation investigates the CM$-$SCALE Flapping Wing of Unmanned Aerial Vehicle (FWUAV) that can accommodate nacelles of the scale of current Unmanned Air vehicle (UAV) designs are complex systems and their utilization is still in its infancy.

The improving design of unmanned aerial vehicle from previous teams by improving the wings and outer body of bird. So, to potentially improve wing design, a complaint joint mechanism is proposed in order to make wing flapping and provide lift and thrust needed to fly. Also, change the wing design from flat wing to airplane wing by using two different airfoils, NACA 0012 …

Un-Conditional: Reflections On Teaching Conditionally-Enrolled Students, Emily Elayne Virtue

All Dissertations

In this study I explore my pedagogical choices in teaching conditionally-enrolled students in a summer bridge program. I address who conditionally-enrolled students are, what support they may need in the classroom, and larger problems in higher education related to conditionally-enrolled students. This study was guided by two research questions: what pedagogical choices do I make in the classroom that foster an engaging environment for conditionally-enrolled and academically underprepared students? What are the emotional and tangible effects of teaching a literature course for conditionally-enrolled students and how does daily reflection of these effects impact pedagogical choices?

I use Scholarly Personal Narrative …

Optimal Control Of Uv-Induced Curing Processes For Layer-By-Layer Manufacturing Of Composites, Shiferaw Damtie Beyene

All Dissertations

Composite materials are becoming viable solutions for making safe, yet lighter and more fuel-efficient vehicles in the automotive industry. However, conventional thermal-based composite manufacturing methods are energy intensive. Potential alternatives are radiation-based curing processes which lend themselves to layer-by-layer additive processes that are suitable for making thick structural parts. This dissertation documents an investigation into ultraviolet (UV) induced curing and layering processes including schemes for their optimization and control. First, a curing process model is developed that is comprised of the coupled cure-kinetics and thermal evolution for a cationic polymerization of a single layer of material. This model is then …

Three Essays On The U.S. Film Industry, Chen Wang

All Dissertations

This dissertation encompasses three papers. My first paper assesses film makers' choices on product quality and variety in film production. Production budget and genre are used to represent quality and variety, respectively. My research is unique in that it exploits the peculiar lack of price variation in the film industry, as ticket prices are the same for each film. I construct a theoretical model of duopoly competition over genre and budget rather than the traditional focus on price. The model predicts that an increase in expected demand will result in an increase in the budgets of the films, as well …

Bifactor Models And Factor Collapse: A Monte Carlo Study, Stephen Robertson

All Dissertations

Though available for over 80 years, bifactor models have recently experienced a resurgence in the psychological and social sciences literature (Reise, 2012). Bifactor models provide an attractive alternative to modeling multidimensional data compared to other approaches (e.g., correlated factors model, second-order factor model). Unlike alternative models, bifactor modeling can effectively model variance that is common between all items and variance that is specific to particular subscales (i.e., specific factors) within a measure. Given its unique benefits, researchers have applied bifactor models to previously validated multidimensional inventories. Researchers have found that when using bifactor modeling on some established scales (e.g., Chen, …

Advances In Reachability Analysis For Nonlinear Dynamic Systems, Kai Shen

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Systems of nonlinear ordinary differential equations (ODEs) are used to model an incredible variety of dynamic phenomena in chemical, oil and gas, and pharmaceutical industries. In reality, such models are nearly always subject to significant uncertainties in their initial conditions, parameters, and inputs.

This dissertation provides new theoretical and numerical techniques for rigorously enclosing the set of solutions reachable by a given systems of nonlinear ODEs subject to uncertain initial conditions, parameters, and time-varying inputs. Such sets are often referred to as reachable sets, and methods for enclosing them are critical for designing systems that are passively robust to uncertainty, …

Development Of Helicoverpa Zea (Lepidoptera: Noctuidae) In Transgenic Corn Producing Bt Toxins And Implications For Resistance, Thomas Bilbo

All Dissertations

The corn earworm, Helicoverpa zea, is a highly polyphagous insect that is a pest of corn, cotton, sorghum, and soybeans in the southern United States. It is currently managed primarily using transgenic cultivars producing insecticidal proteins derived from the bacterium Bacillus thuringiensis (Bt) in corn and cotton, and foliar insecticides in sorghum and soybeans. However, the development of resistance to several Bt toxins has been reported and is the primary threat to the success and longevity of Bt crops. We performed a number of field and laboratory experiments over three years to investigate the development, survival, and feeding behavior …

Determining Wind Turbine Drivetrain Test Bench Capability To Replicate Dynamic Loads: Evaluation Methods And Their Validation, Philippe Giguère

All Dissertations

Wind turbine drivetrain test facilities are impressive laboratories that offer a controlled environment to test the response of drivetrains under design conditions. The stochastic nature of the wind results in highly dynamic loads and this is reflected in the design standards and certification process of wind turbines. A wide range of wind conditions and turbine operating states are prescribed as design load cases. The design process of a wind turbine yields thousands of time series of fluctuating forces, bending moments and speed to cover these design load cases. The capability of a test bench to replicate such dynamic loads has …

Nanomaterials-Based Electrodes For Lithium-Ion Batteries And Alcohol Fuel Cells, Lakshman K. Ventrapragada

All Dissertations

This dissertation describes my research on surfactant-free synthesis of nanomaterials with applications for alcohol fuel-cell electrodes, and design and fabrication of nanomaterials-based current collectors that improve the performance of lithium-ion batteries (LIBs) by replacing existing current collectors.

Chapter 1 provides a background on the electroanalytical tools used in this research, and an introduction to fuel cells and LIBs.

Chapter 2 describes a novel synthesis method for fabricating gold-graphene composites by laser ablation of a gold strip in water. A well-known limitation in the fabrication of a metal-graphene composite is the use of surfactants that strongly adsorb on the metal surface …

Culturally Specific Shape Grammar: Formalism Of Geringsing Textiles Patterns Through Ethnography And Simulation, Nyoman Dewi Pebryani

All Dissertations

The patterns design in Geringsing textiles are unique because they are produced using the double-ikat weaving technique. The double-ikat weaving technique is found in only three places in the world: India, Indonesia, and Japan. Geringsing textile is produced in Tenganan Pegringsingan in Bali, Indonesia, and its culture passes from generation to generation as an oral tradition. To preserve, document, and digitize this knowledge, a sequential research methodology of ethnography and simulation with visual computation analysis—shape grammar—was employed in this study. This study was divided into several stages: (1) learning the double-ikat technique from the artisans on the site, (2) translating …

Compressing Deep Neural Networks Via Knowledge Distillation, Ankit Kulshrestha

All Theses

There has been a continuous evolution in deep neural network architectures since Alex Krizhevsky proposed AlexNet in 2012. Part of this has been due to increased complexity of the data and easier availability of datasets and part of it has been due to increased complexity of applications. These two factors form a self sustaining cycle and thereby have pushed the boundaries of deep learning to new domains in recent years.

Many datasets have been proposed for different tasks. In computer vision, notable datasets like ImageNet, CIFAR-10, 100, MS-COCO provide large training data, with different tasks like classification, segmentation and object …

Watt - Libraries Summit, Clemson University

Presentations

No abstract provided.

14th Annual Focus On Creative Inquiry Poster Forum Program, Clemson University

Focus on Creative Inquiry

The Focus on Creative Inquiry (FoCI) Poster Forum is an annual event in which Creative Inquiry (CI) teams can present their research and project accomplishments through posters and interactive displays. It is a celebration of student and mentor collaborations and accomplishments! Teams take this opportunity to develop and hone their communication skills.