Digital Commons Network^™

Wave Propagation And Imaging In Structured Optical Media, Zun Huang

Open Access Dissertations

Structured optical media, usually characterized by periodic patterns of inhomogeneities in bulk materials, provide a new approach to ultimate control of wave propagation with possible practical applications: from distributed feedback lasers by diffraction gratings, to highly nonlinear performance for super-continuum generation, to fiber-optic telecommunications by microstructured photonic crystal fibers, to invisibility cloaking, to super-resolution imaging with metamaterials etc.

In particular, structured optical media allow to manipulate the wave propagation and dispersion. In this thesis, we focus on engineering the propagation phase dispersion by modulating the compositions and dimensions of the periodic elements. By tailoring the dispersion in momentum space, we …

Implementing A Wireless Monitoring Solution For A Biomechanical Telemetry System, Hyung Suk Kim

Open Access Theses

Sport-related Traumatic Brain Injury (TBI) is one of the major concerns for collision based sports athletes and their families. The ability to measure impacts on the head is imperative to monitor brain injury and prevent serious TBI. Recent research by the Purdue Neurotrauma Group (PNG) indicates that accumulation of subconcussive impacts may cause permanent neurological damage. Currently available commercial impact monitoring systems are designed as an event-based models which collect impact data above pre-determined acceleration thresholds. To track long-term effects of sub-concussive impacts, event-based modeling is inadequate. The PNG developed a biomechanical sports telemetry system that is capable of storing …

Optical Sub-Diffraction Limited Focusing For Confined Heating And Lithography, Luis M. Traverso

Open Access Dissertations

Electronics and nanotechnology is constantly demanding a decrease in size of fabricated nanoscale features. This decrease in size has become much more difficult recently due to the limited resolution of optical systems that are fundamental to many nanofabrication methods. A lot of effort has been made to fabricate devices smaller than the diffraction limit of light. Creating devices that are capable of confining fields by means of interference patterns of propagating wave modes and surface plasmon, has proven successful to confine light into smaller spot sizes.

Zone plate diffraction lenses generate spots with dimensions very close to the diffraction limit. …

In-Column Polymer Modifications: Advancing Polymer Bonded Phases, Alexis G. Huckabee

Open Access Dissertations

Glycosylation is the most common post-translational modification affecting protein activities, including delivery to cell surface, binding affinity, and mediating different physiological effects. Separations of glycoproteins and their glycoforms are essential for drug discovery and development, identification of potential disease biomarkers and quality control. The efficiency of glycoprotein separations is limited by the bonded phases, requiring advances in chromatographic materials. Such advances would improve resolution, allowing for more species to be isolated from a mixture and studied.

Our group found that submicrometer nonporous silica stationary phases with tethered polymer chains (acrylamide) give excellent hydrophilic liquid chromatography (HILIC), a common method used …

Multimedia Techniques For Construction Education And Training, Wayne A. Bunnell

Open Access Theses

The current profession of civil engineering often focuses education and training on code compliance rather than constructability and construction techniques. Also, it is well accepted that it takes a decade or more for engineers to develop a high-level project construction understanding and many state departments of transportation rely on in-field training for entry-level inspectors, with little or no education provisions for contractors. This research investigated the use of time-lapse photography to develop training and education material that will improve the understanding of project construction and crucial quality control specifications of an entry-level engineer, contractor, or inspector. Overall, the project team …

Size Scaling Of Strength And Toughness For 3d Printed Polymer Specimens, Darren Thomas Bell

Open Access Theses

To find material systems that offer low density and high strength, stiffness or toughness, hierarchically designed material systems have provided a promising research area. This thesis lays the groundwork for designing efficient micro-architectured material systems by characterizing size effects for 3d printed polymer parts. Two methods were used to analyze data from 3-point bend tests for specimens of varying size: the load-separation method was used for finding the point of crack growth initiation and Bazant’s method was used to find shape independent strength at failure. The strength values were used as inputs for finding size independent material constants within a …

Antibacterial Activity Of Essential Oil Encapsulated Sodium Iota-Carrageenan Fibers, Carlos D. Carter

Open Access Theses

Spoilage microorganisms cause food waste and loss of quality. While the foodborne pathogen outbreaks lead to thousands of hospitalizations and deaths. Essential oils (EOs), plant extracts, possess the required antimicrobial activities and thus their usage stands out as a feasible approach for controlling the undesirable bacterial growth in food systems. However, EOs are highly volatile and lose their activity upon exposure to environmental conditions. In this regard, their encapsulation in Generally Recognized As Safe (GRAS) matrices such as food grade polysaccharides especially iota-carrageenan could be one of the viable alternatives. Iota-carrageenan, sulfated polysaccharide from marine algae, is being used in …

Mechanism Of Shot Peening Enhancement For The Fatigue Performance Of Aa7050-T7451, Daniel James Chadwick

Open Access Theses

Shot peening is a dynamic cold working process involving the impingement of peening media onto a substrate surface. Shot peening is commonly employed as a surface treatment technique within the aerospace industry during manufacturing, in order to improve fatigue performance of structural components. The compressive residual stress induced during shot peening is understood to result in fatigue crack growth retardation, improving the performance of shot peened components. However, shot peening is a compromise between the benefit of inducing a compressive residual stress and causing detrimental surface damage. Due to the relatively soft nature of AA7050-T7451, shot peening can result in …

Lightcraft Previzion In Distance Education, Perry L. Cox

Open Access Theses

Visual Effects has continued to progress at an astonishing rate and green screen technology can be seen in all aspects of the video industry from Hollywood blockbusters down to training videos and distance education.

As video technology has increased, so has the quality and capability of distance education. Purdue University has set itself to be at the forefront of distance education. This study looked to evaluate Purdue's investment in the Lightcraft Technology's Previzion system and its impact on distance education at Purdue. There were 65 initial participants and this study compared the impact of two separate videos on their learning. …

Thermal Transport In Lithium Ion Batteries: An Experimental Investigation Of Interfaces And Granular Materials, Aalok Jaisheela Uday Gaitonde

Open Access Theses

Increasing usage and recent accidents due to lithium-ion (Li-ion) batteries exploding or catching on fire has inspired research on the characterization and thermal management of these batteries. In cylindrical 18650 cells, heat generated during the battery's charge/discharge cycle is poorly dissipated to the surrounding through its metallic case due to the poor thermal conductivity of the jelly roll, which is spirally wound with many interfaces between electrodes and the polymeric separator. This work presents a technique to measure the thermal conduction across the metallic case-plastic separator interface, which ultimately limits heat transfer out of the jelly roll.

The polymeric separator …

Remote Sensing Of Snow Using Bistatic Radar Reflectometry, Abi Komanduru

Open Access Theses

Snow and ice processes are a critical part of the Earth’s hydrological and climate cycles. These processes can serve as an important source of fresh water as well as a cause of flooding. Various missions have been proposed by NASA and ESA for the purpose of remote sensing of snow. This research looks at applying bistatic radar reflectometry to the remote sensing of snow water equivalent. The resulting phase offset from changes in optical path length due to reflection through snow are the primary measurements made. The research uses data from a field campaign in Fraser, CO, involving an instrument …

Improvement Of A Biomechanical Telemetry System Hardware Platform, Soon Ho Kwon

Open Access Theses

Traumatic brain injuries (TBI) while playing sports are a major concern for the general public today. Recently, studies have shown that repetitive subconcussive hits can lead to neurological disorders. In order to prevent the athletes from suffering traumatic brain injuries, many organizations related to contact based sports and the military employ commercialized head impact telemetry systems. However, a majority of the commercialized systems is event based which only collects the linear acceleration that exceeds a certain threshold. To accurately record and utilize the data from the impact telemetry system, it is necessary to record all the linear and angular acceleration …

Hua Qian Zhao Zui Shou Looking For Trouble At Own Expense - A Study Of Tourist (Mis)Behaviors, Yue Li

Open Access Theses

The study sets two objectives. The first is to investigate how an array of tourist misbehaviors was perceived by the young generations of the United States and China. The second is to examine factors that could explain any perceptual differences between young Americans and Chinese. Five research questions were developed and addressed for the first objective through online surveys by comparing the perceptions of American respondents and Chinese respondents on a list of tourist misbehaviors. They are: 1) What are the annoyance levels of tourist misbehaviors perceived by American college students? 2) What are the annoyance levels of tourist misbehaviors …

Measuring The Effect Of Cold Storage, Captive Supply, And Concentration On The Marketing Margin In The U.S. Pork Industry, Yuhang Liu

Open Access Theses

This study investigates the implication of key decision variables at the control of processing firms in a concentrated industry. Succinctly, the decisions examined affect the firm's ability to buffer short run supply and demand fluctuations through storage and access to an alternative source of specialized inputs essential to production. What makes them different in the context of this research is a focus on high-throughput processing plants where capacity utilization can result in cost efficiencies and a high degree of market concentration where adjustments in quantity demanded of the specialized input can affect its price and where adjustments in the quantity …

Degradation Of High Performance Polymeric Fibers: Effects Of Sonication, Humidity And Temperature On Poly (P-Phenylene Terephthalamide) Fibers, Nelyan Lopez-Perez

Open Access Theses

High performance fibers are characterized by properties such as high strength and resistance to chemicals and heat. Due to their outstanding properties, they are used on applications under harsh environments that can degrade and decrease their performance. Fiber degradation due to different chemical and mechanical factors, is a process that begins at a microstructural level. Changes in the polymer’s chemical or physical structure can alter their mechanical properties. Knowledge of the structure-properties relationship and the effects of environmental chemical and physical factors over time, is crucial for the improvement and development of high performance fibers.

In this study ballistic fibers …

Modeling Relative Habitat Suitability And Movement Behavior Of Invasive Burmese Pythons In Southern Florida, Holly E. Mutascio

Open Access Theses

Invasive Burmese pythons are established in the Everglades and are altering the ecology of southern Florida. Their distribution in Florida is expanding northward into more urbanized and fragmented habitats. An understanding of the suitability of habitat throughout southern Florida for Burmese pythons and their interaction with Florida’s landscapes through movement behavior is vital for predicting the python’s ability to persist in habitats outside of the Everglades. In this thesis, we use ecological modeling to predict habitat suitability and to investigate personality-dependent dispersal.

First, we used presence-only ecological niche modeling with correction for sampling bias to identify the key landscape variables …

Facebook And User Experience: Evaluating Brand Equity Of Purdue University Residences, Jackelyn Perkins

Open Access Theses

This study investigated how brand equity was perceived on the Purdue University Residences’ Facebook page by applying a user experience method. From a review of previous literature, Website Experience Analysis was identified and performed to evaluate brand equity. This study addressed and explored various themes throughout the data. The results showed how page content and user interactions within a Facebook page influence participants’ perceptions of brand equity.

In-Situ Particle Sizing Of Agglomerates In Aluminized Solid Composite Propellants Using Digital Inline Holography (Dih), Michael S. Powell

Open Access Theses

Aluminized ammonium perchlorate composite propellants (APCP) form large molten agglomerated particles that can result in poor combustion performance and increased two-phase flow losses. Quantifying agglomerate size distributions is important for assessing these losses for different types of aluminum fuels that can help improve rocket performance. It is highly desirable to measure particle sizes in-situ using non-intrusive optical methods, rather than conventional particle collection, which can have large uncertainties. Regular high-speed microscopic imaging suffers from a limited depth of field. Digital inline holography (DIH) is an alternative approach that results in 3D information through numerical reconstruction. In this paper, DIH approach …

A Small-Scale Testbed For Large-Scale Reliable Computing, Jason R. St. John

Open Access Theses

High performance computing (HPC) systems frequently suffer errors and failures from hardware components that negatively impact the performance of jobs run on these systems. We analyzed system logs from two HPC systems at Purdue University and created statistical models for memory and hard disk errors. We created a small-scale error injection testbed—using a customized QEMU build, libvirt, and Python—for HPC application programmers to test and debug their programs in a faulty environment so that programmers can write more robust and resilient programs before deploying them on an actual HPC system. The deliverables for this project are the fault injection program, …

Effect Of Temperature On Deep Lined Circular Tunnels In Isotropic And Transversely Anisotropic Elastic Ground, Fei Tao

Open Access Theses

A tunnel is a passageway constructed through soil or rock. It is one of the most important underground structures and has been widely used in transportation. Much research has been done on tunnel performance and on the interaction between ground, excavation, liner installation and support. The work has provided a better understanding of the interplay that exists between deformations and stresses transferred from the ground to the support. Significant insight into the problem has been provided by closed-form analytical solutions. A number of analytical formulations have been obtained for underground openings and lined tunnels under different scenarios, namely shallow or …

The Influence Of Alkalinity Of Portland Cement On The Absorption Characteristics Of Superabsorbent Polymers (Sap) For Use In Internally Cured Concrete, Juan D. Tabares Tamayo

Open Access Theses

The concrete industry increasingly emphasizes advances in novel materials that promote construction of more resilient infrastructure. Due to its potential to improve concrete durability, internal curing (IC) of concrete by means of superabsorbent polymers (SAP) has been identified as one of the most promising technologies of the 21st century. The addition of superabsorbent polymers into a cementitious system promotes further hydration of cement by providing internal moisture during the hardening and strength development periods, and thus limits self-desiccation, shrinkage, and cracking.

This thesis presents the work performed on the series of cement pastes with varying alkalinity of their pore solutions …

An Event Detection Approach Based On Twitter Hashtags, Shih-Feng Yang

Open Access Theses

Twitter is one of the most popular microblogging services in the world. The great amount of information made Twitter an important information channel for people to know and share news. Hashtag is a popular feature when people use Twitter. It can be taken as human labeled information and is useful for people to identify the topic of a tweet. Many researchers have proposed event-detection approaches that can monitor Twitter data and determine whether special events, such as accidents, extreme weather, earthquakes, or crimes, are happening. Although many approaches considered hashtag as one of their features, few of them explicitly focused …

The Role Of Hif1alpha And Hif2alpha In Muscle Development And Satellite Cell Function, Shiqi Yang

Open Access Theses

Hypoxia inducible factors (HIFs) are central mediators of cellular responses to fluctuations of oxygen, an environmental regulator of stem cell activity. Muscle satellite cells are myogenic stem cells whose quiescence, activation, self-renewal and differentiation are influenced by microenvironment oxygen levels. However, the in vivo roles of HIFs in quiescent satellite cells and activated satellite cells (myoblasts) are poorly understood. Expression analyses indicate that HIF1α and HIF2α are preferentially expressed in pre- and post-differentiation myoblasts, respectively. Interestingly, double knockout of HIF1α and HIF2α (HIF1α/2α dKO) in embryonic myoblasts results in apparently normal muscle development and growth. However, HIF1α/2α dKO in postnatal …

Metrics Of Critical Pair Identification, Zixu Zhang

Open Access Theses

Critical Pair Identification works as a potential assistive tool for human air traffic controllers by identifying potentially dangerous situations that are not detected by proposed automated separation assurance systems. This concept specifically considers conflicts that might arise if aircraft unexpectedly deviate from their planned flight path in the near future. Five metrics of the critical pair concept, Critical Pair Count, Time to Risk Exposure, Lead Time, Risk Exposure Duration and Blunder Sensitivity Index, have been developed and mathematically defined to characterize the safety level of an aircraft pair or a volume of air space. Algorithm that computes proposed metrics is …

Forest Industry Byproducts Improve Soil Quality And Increase Pepper Growth In Three Soils Infested With Phythophthora Blight, Xiaojun Zhao

Open Access Theses

Phytophthora blight is a serious threat to the Midwest vegetable industry, because the oomycete pathogen responsible for this disease, Phytophthora capsici, has a wide host range, can spread quickly in fields, and produces resilient oospores that can survive in soil for years. Phytophthora capsici has become resistant to commonly used fungicides and resistant crop varieties are rare. Amending soil with complex organic substrates has potential to improve soil quality and suppress soil-borne pathogens including P. capsici. Indiana has a significant forest industry with many residual products that could be used as locally available amendments to meet this goal. …

Utilization Of Ferrioxamine Microarrays For The Rapid Detection Of Pathogenic Bacteria, Nigam Bir Arora

Open Access Dissertations

Siderophores are low-molecular weight species utilized by bacteria for the sequestration of iron, an essential nutrient. Siderophores and their cognate receptors are considered to be virulence factors, due to their prominent role in pathogenicity. The work presented here focuses on ferrioxamine (FOx) as an “immutable” ligand for pathogen detection. A number of bacterial strains expressing high-affinity FOx receptors were identified by a proteomic BLAST search, and screened against microarrays patterned with FOx conjugates for detection using label-free optical imaging. Aspects such as inkjet printing and surface chemistry, iron-limiting conditions and bacterial selection protocols, and linker conjugate design were addressed and …

A Unique Perspective On The Demand For Livestock Product Attributes, Elizabeth S. Byrd

Open Access Dissertations

Consumers are increasingly concerned about the social and environmental impacts of the foods they purchase. Both choice experiments and best-worst scaling (BWS) methodology have been used to elicit consumer willingness to pay (WTP) for food attributes and the relative importance of food attributes to consumers. The dissertation consists of four essays. Chapter 2 presents a formal law review article exploring the laws associated with wild game harvest, consumption, and inspections. The remaining three essays (Chapters 3-5) each address an extension or application of choice experiment and/or BWS methodology focused on credence attributes of meat products. Two online surveys were used …

Authentic Science In Education: Studies In Course-Based Research At The United States Military Academy, Anthony M. Chase

Open Access Dissertations

This dissertation consists of two studies at the United States Military Academy. Both studies involve the use of Course-based Undergraduate Research Experiences (CUREs). These experiences give students the ability to engage in undergraduate research at an early point in their academic career by replacing traditional laboratory activities with semester-long research projects. Both studies show an implementation of this type of instruction from the Center for Authentic Science Practice in Education (CASPiE). Study 1 shows the specific method of implementation at the military academy and explores learning-based outcomes. Primarily the outcome of critical thinking is demonstrated. Critical thinking is a construct …

Visual Analytics Of Location-Based Social Networks For Decision Support, Junghoon Chae

Open Access Dissertations

Recent advances in technology have enabled people to add location information to social networks called Location-Based Social Networks (LBSNs) where people share their communication and whereabouts not only in their daily lives, but also during abnormal situations, such as crisis events. However, since the volume of the data exceeds the boundaries of human analytical capabilities, it is almost impossible to perform a straightforward qualitative analysis of the data. The emerging field of visual analytics has been introduced to tackle such challenges by integrating the approaches from statistical data analysis and human computer interaction into highly interactive visual environments. Based on …

A Descriptive Case Study: Investigating The Implementation Of Web Based, Automated Grading And Tutorial Software In A Freshman Computer Literacy Course, Glen J. Coulthard

Open Access Dissertations

Students in higher education require satisfactory computer skills to be successful. While today’s students may have greater exposure to technology, research shows that their actual computer knowledge and skills are superficial and narrow. As a result, the freshman computer literacy course remains an important curricular component. This study investigates the implementation of an innovative Web-based technology for delivering software proficiency training for Microsoft Office. Building upon decades of end-user computing satisfaction and technology acceptance research, the purpose of the study is to describe the instructor and student experiences that result from the implementation and use of MyITLab educational software. The …