Digital Commons Network^™

Design And Additive Manufacturing Of Shape Recovery Polymer Lattice Structure, Chien-Chun Chou

Open Access Theses & Dissertations

Studied mechanical properties of 3D printed metamaterials of BCC, FCC, and BFCC structure.

Association And Predictive Abilities Of Jump And Throw Tests To Track Performance In Division I Athletes, Nicholas R. Cubillos

Open Access Theses & Dissertations

Sprinting jumping, and throwing are of the most vital abilities in track & field. Although various studies investigated relationships among these three aspects, there is limited empirical evidence as to how they may be correlated and predictive towards track performance. Purpose: To determine associations and predictive abilities of four field performance tests among a static (Accel30) and flying (Fly30) 30-meter sprint. This study also aimed to ascertain associations of kinematic and kinetic components of all field assessments to Accel30 and Fly30 sprint times. Methods: 23 subjects (18-25 years, 1.77 ± 0.10 meters, 78.67 ± 24.15 kg) performed two trials of …

Mathematical Modeling, Optimal Control And Stability Analysis For Dynamic Supply Chains, Yasser Alberto Davizon

Open Access Theses & Dissertations

Dynamic supply chains (SC) are important to reduce inventory, to enable the flow of materials, and maximize profits. By this, dynamic SC require proper decision-making with effective performance and synchronization. In operations and production planning processes, decision-makers develop convenient and suitable decisions, to validate their hypoThesis about which decisions incorporate more profit while reducing costs on enterprise operations. Based on this, inventory management plays a crucial point in the supply chain analysis. In general, SC processes raw material, cash, and information flows, taking into account the demand profile of the system. This research work presents the mathematical modeling, optimal control, …

Development Of Software Tools And Experimental In Situ Electron Spin Resonance For Characterizing The Magnetic And Electrocatalytic Properties Of Transition Metal Chalcogenide Crystals, Jose Armando Delgado

Open Access Theses & Dissertations

Studying the magnetic properties and crystal defects of transition metal chalcogenide crystals is of paramount importance for utilizing them for next generation spintronics devices and hydrogen evolution reaction catalysts. Hydrothermally grown transition metal chalcogenide nanocrystals (MoS2, Ru2S3, Rh2S3, Co2S8) were chosen as catalysts for the hydrogen evolution reaction due to their low dimensionality and previous utilization as catalysts for hydrodesulfurization. The relationship between crystal defect sites and catalytic activity must be discerned to maximize the efficiency of hydrogen production during the hydrogen evolution reaction. ESR spectroscopy was utilized as a spin sensitive technique to study the defects and local changes …

Uav Parameter Estimation Through Machine Learning, Andres Enriquez Fernandez

Open Access Theses & Dissertations

Parameter identification of Unmanned Aerial Vehicles (UAV) is very helpful for understanding cause-effect relationships of physical phenomenon, investigating system performance and characteristics, fault diagnostics, control development/tuning, and more. Traditional ways of performing parameter identification involve establishing a mathematical model that describes the system's behavior. The equations in the model contain parameters that are estimated indirectly from measured flight data. This parameter identification process requires knowledge of the physics involved. Also, it necessitates a careful consideration of the aircraft instrumentation for accurate measurements. It also requires careful design of the flight maneuvers to ensure thorough excitation of the flight dynamics involved. …

Faculty Attitudes And Perspectives About Community Engaged Scholarship At An Engaged Institution, Azuri Lizeth Gonzalez

Open Access Theses & Dissertations

Community engaged scholarship has become a method for higher education institutions to respond to public and societal needs. Decades into the establishment of the "engaged institution," studies reveal that higher education presents challenges for faculty to effectively succeed in academia while pursuing a community engaged scholarship agenda. This study employs the use of a constructivist grounded theoretical approach to explore faculty attitudes and perspectives on community engaged scholarship and the role the engaged intuition may have in their views. This study found that faculty were introduced to the term by their institutions but their views and understanding of community engaged …

Active Seismic Studies In Lemon Creek Valley Glacier, Juneau, Alaska: Characterization Of Subglacial Sediments To Understand Glacier Dynamics, Lucia Fernanda Gonzalez

Open Access Theses & Dissertations

Deformation and flow properties of subglacial sediments as well as the presence and volume of water at the ice/bed interface strongly influence glacier dynamics. Studies of Lemon Creek Glacier, a small temperate valley glacier in the Juneau Icefield, near Juneau, Alaska, have shown that the glacier is rapidly retreating, with a negative mass balance every year since 1957. However, the bed topography and properties of subglacial sediments at the base of Lemon Creek Glacier remained unknown until now. In this project, we process and interpret ~1-km-long NW-SE trending active-source seismic reflection profiles collected during June and July 2017 near the …

Development On Of An Unmanned Aerial Vehicle-Based Orangutan Population Assessment And Monitoring Method For The Multifunctional Landscape Of East Kalimantan, Indonesia, Muhammad Sugihono Hanggito

Open Access Theses & Dissertations

Deforestation, habitat degradation, and other forms of land conversion are threatening the existence of orangutans (Pongo spp.), the critically endangered great apes that only live on the two large Sunda-shelf islands of Sumatra and Borneo. Currently, orangutan populations persist not only within conservation or protected areas but also in other functional landscapes such as forest/acacia plantations, oil palm plantations, and mining concessions. The presence of orangutan populations in this recently modified multifunctional landscape has the potential to exacerbate human-orangutan conflict, which could further threaten orangutan populations. Lack of information about the distribution and size of orangutan populations hampers long term …

Dating-Up: Discrepancy Of Inclusion Of Other In The Self As A Result Of Partner-Self Mate Value Discrepancy, Jacqueline Lechuga

Open Access Theses & Dissertations

Inclusion of other in the self â?? the experience of closeness as overlapping selves â?? has a critical role in the success of romantic relationships. Romantic partners, however, might experience differences in their inclusion of each other, which can be problematic. Therefore, it is important to identify what factors can result in a discrepancy of inclusion of other in the self between romantic partners. Study 1 tested how perceived differences in desirability between the self and a romantic partner are associated with inclusion of other in the self and closeness. Romantic couples (n=122) completed measures that assessed inclusion of other …

Benchmarking Machine Learning Methods For Molecular Property Prediction, Govinda Bahadur Kc

Open Access Theses & Dissertations

Machine learning (ML) techniques have been widely applied in a variety of areas ranging from pattern recognition, natural language processing, and computer games to self-driving cars, clinical diagnostics, and molecular structure prediction easing day to day life of human beings. Drug discovery is an expensive, complex, and time taking process. Currently, the pharma industry is hoping to leverage machine learning methods in expediting the drug discovery process. Molecular property prediction is one of the most important tasks in drug discovery. While developing a new drug relies on a proper understanding of molecular properties, there has been great interest in the …

Mechanical Performance Of Ebm Ti-6al-2sn-4zr-2mo Influenced By The Effects Of Different Hot Isostatic Pressing Treatments, Miguel Lopez

Open Access Theses & Dissertations

Electron Beam Melting (EBM) is an additive manufacturing process that presents a lower level of internal defects in comparison to Selective Laser Melting (SLM). Pairing Hot Isostatic Pressing (HIP) with Additive Manufactured metal parts, sub-surface voids can be eliminated through high pressure and temperature. This significantly improves fatigue life, impact toughness, creep, rupture strength, and tensile ductility. In this investigation, Ti-6Al-2Sn-4Zr-2Mo samples manufactured in the Arcam's Q20 system will be tested as per ASTM E8 Standard Test Methods for Tension Testing of Metallic Materials. Different variants of Hot Isostatic Pressing (HIP) treatments were analyzed and compared. Tensile testing was performed …

Planar Motion Control Of A Cube Satellite Using Cold Gas Thrusters, Christian Lozoya

Open Access Theses & Dissertations

This Thesis presents a mathematical model developed for the computational simulation ofCubeSat movement using four thrusters that permit uniaxial translation and rotation. Arbitrary functions are fit to boundary conditions to simulate the force, acceleration, velocity, and displacement of the CubeSat along a plane. The model is used to derive a motion control algorithm assuming constant pressure and mass. A single model describes both translation and rotation. This Thesis also explores the relationship between propellant consumption and the time required to complete a displacement implied by the model.

Optimization Of Regional Scale Numerical Weather Prediction & Air Quality Model For The Paso Del Norte Region, Suhail Mahmud

Open Access Theses & Dissertations

Improvement of the Accuracy and Forecast capability of the Numerical Weather Prediction (NWP) models and Air Quality Models (AQM) are critical issues in today's scientific study of Meteorology and Air Pollution. The models for these predictions are dependent on topography, climate, initial and boundary conditions, domain size, and computational efficiency. Different techniques such as Data Assimilation, Ensemble Methods, Increased Computing Capacity to achieve higher model resolution, and Improved Physics Schemes can be used to address this problem. In this study, the NWP models, the Weather and Research Forecast (WRF), and the HYSPLIT models, were enhanced for the Paso Del Norte …

Performance Measure Methodology Of Project Management Practices In Local Government Agencies, Johanes Johanes Makahaube

Open Access Theses & Dissertations

Local government agencies have adopted project management practices to deliver public work projects. The agencies need to measure project management performance to ensure the consistency, control, and monitoring of the project delivery process. However, local government agencies have not adopted a systematic method to measure the organization's project-management performance. At present, there is a gap regarding methods to measure project management performance in delivering construction projects. This study aims to assist local government agencies in improving their project management processes by implementing a comprehensive methodology to assess project management's performance. This dissertation is organized into three major chapter-papers: the first …

Development Of An Automated Ultrasonic Wire Embedding Process For Use With Material Extrusion Additive Manufacturing And Rapid Electronics Fabrication, Nikki L. Martinez

Open Access Theses & Dissertations

Polymers have been used in Additive Manufacturing (AM) by many industries for rapid prototyping. Parts created using polymer AM however are known to be relatively expensive thus limiting them to small volume production and making them inapplicable for mass production, while their inherent porous and anisotropic properties make them mechanically inferior to parts made using traditional methods such as injection molding. As projects demand more efficient designs, and at the same time ask for more complex features, AM, combined with other manufacturing processes, like Ultrasonic Wire embedding, can streamline and consolidate assemblies. In the realm of composite and multifunctional assemblies, …

Towards The Development Of A Cohesive Design-Driven Code Quality Metrics, Omar Masmali

Open Access Theses & Dissertations

Software complexity is an indicator of expected future maintenance and sustainability. Excessive complexity suggests that software or a component of software has a design or implementation that is difficult to understand, modify, and maintain. Several complexity measures have been developed by researchers to identify and characterize degrees of complexity. Code smells are widely adopted as indicators for low code quality. Many studies have adopted fixed threshold values for code smells and other quality metrics. These fixed threshold values often ignore the uniqueness of each software system and the unique roles each component play. Moreover, these thresholds are largely fixed throughout …

The Digital Literacy Practices Of Transfronterizx Esol College Students: Los De Esol, Laura E. Mendoza

Open Access Theses & Dissertations

This dissertation aims to contribute knowledge to the literature about ESOL students' digital literacy practices related to educational purposes. I studied the varied digital literacy practices the students used as mediating tools to perform their university activities (e.g., crossing to come to school, communicate with classmates/instructors about assignments, completing assignments). This study takes place on the U.S. side of the borderland area of El Paso, Texas-Ciudad Juarez, Chihuahua, Mexico. The participants were 43 transfronterizx ESOL college students, who were young adults between 18-25 years of age enrolled in the ESOL program at Sun University. I draw on ethnographic and netnographic …

Expression, Purification, And Characterization Of Recombinant Human Npas2, Brenda Moreno

Open Access Theses & Dissertations

Many living organisms have biological clocks known as circadian rhythms that control various physiological and behavioral processes, tailored with the day and night. At the cellular level, the circadian clock drives daily rhythms with a transcriptional-translational feedback loop (TTFL) established by multiple transcription factors and genes under their regulation. Circadian Locomotor Output Cycles Kaput (CLOCK) and Brain and Muscle ARNT-like protein 1 (BMAL1) are two of those transcription factors, initiating the TTFL by forming a heterodimeric complex that bind to DNA promoters. Neuronal PAS domain protein 2 (NPAS2) is a functional analog to CLOCK. Less knowledge about NPAS2, in contrast …

Discovery Of Glycan-Based Biomarkers For Cutaneous Leishmaniasis And Chagas Disease By Reversed Immunoglycomics, Alba Lucia Montoya

Open Access Theses & Dissertations

Protozoa are the causative agents of a number of diseases that affect humans and mammalian animals. Several forms of leishmaniasis are caused by different Leishmania species (Leishmania spp.), while Chagas disease (CD) is caused by the parasite Trypanosoma cruzi (T. cruzi). These members of the Trypanosomatidae family have characteristic glycoconjugates broadly distributed on their cell surfaces, which can be useful for diagnosis and follow-up of chemotherapy for the diseases.

Leishmania spp. expresses an “exotic” surface glycocalyx mainly composed of a number of glycosyl-phosphatidylinositol (GPI)-anchored proteins, a complex lipophosphoglycan (LPG) and a family of low-molecular mass glycoinositol-phospholipids (GIPLs), some of them …

The Framing Of Recycling Information Toward Behavioral Intention, Perla Celeste Perez

Open Access Theses & Dissertations

Most studies have measured the relationship between self-reported recycling behavior and attitudes. Very little research has focused on how the framing of recycling information moderates this relationship. Moreover, even less research has examined how communication messages directly impacts self-efficacy of recycling. Thus, the aim of this study is to further understand factors that influence self-reported recycling behavioral intention and information framing. We predicted that pro-environmental behavior would be positively associated with climate change beliefs and recycling efficacy. We also predicted that individuals that read a positive recycling article would be more likely to intend to recycle than individuals who read …

Design Of Experiments Analysis Of Powder Removal Methods For Ebm Manufactured Ti-6al-4v Parts, Luis Cesar Ramos Castañeda

Open Access Theses & Dissertations

Additive Manufacturing is a technology that allows the on-demand manufacturing of complex geometries that cannot be fabricated through traditional subtractive manufacturing methods. Powder Bed Fusion is one of the seven categories of Additive Manufacturing with two subcategories, the Laser Beam Melting and the Electron Beam Melting. Freedom of design, rapid prototyping, and customization are some of the benefits that this technology provides. Like any technology, there are limitations for each category and subcategory. The Electron Beam Melting uses the electron beam to pre-heat the powder bed, reducing the temperature difference between the build part and powder bed, causing the surrounding …

A Full Collegiate Volleyball Season Does Not Influence Jumping Or Landing Performance In Freshmen And Sophomore Players, Christian Noel Sanchez

Open Access Theses & Dissertations

Knee injuries are devastating and typically experienced by athletes when performing jumping and landing tasks throughout a complete collegiate volleyball season. The purpose of this study was to examine changes in lower extremity strength, frontal plane knee angles and moments, jump performance during a countermovement and approach jump before and after a complete Division I collegiate volleyball season in female volleyball freshman and sophomores. Eight freshman/sophomore female collegiate volleyball players participated in the study. Lower extremity strength was assessed using an isokinetic dynamometer, kinematic and kinetic data were obtained through three-dimensional motion capture system and force platforms, respectively. Participants performed …

Performane Characterization Of Stabilized Materials In Pavement Foundations, Mohammad Rashidi

Open Access Theses & Dissertations

Cementitious Stabilization has been widely used to improve the strength and durability of granular materials for the construction and rehabilitation of pavement structures. Improved mechanical properties and durability of the stabilized materials combined with relatively low cost makes it an attractive method for design engineers. Although this technique appears simple and straight forward, engineering properties of individual soils and aggregates may alter widely due to heterogeneity in soil composition, difference in micro structure among soils, heterogeneity of geologic deposits and differences in chemical interactions of water with soil particles. These differences necessitate the comprehensive study in order to provide the …

Testing The Reliability And Flexibility Of Digitizers Adapting The Rf/If Signals Over Ip Applications Using A Testbed Platform, Jose Carlos Sandoval

Open Access Theses & Dissertations

As physical constraints can be challenging for Radio Frequency (RF) telemetry, a new solution has been exploited to support the demand for RF transmissions. As frequency spectrum gets crowded with more technologies, a solution to a reliable transmission is needed. Digitizers can mitigate many of the physical constraints in order to achieve a successful RF transmission. The method includes the conversion of the RF signals to be sent over IP networks, transmit and de-convert the signal. IP networks will mitigate many disadvantages over a regular signal transmission. The authority in charge to allocate frequency bands is the Federal Communications Commission …

Sex Differences In The Mechanisms That Modulate The Neurochemical Effects Of Nicotine, Kevin Uribe

Open Access Theses & Dissertations

Prior behavioral studies in our laboratory revealed that overexpression of the stress peptide, corticotrophin-releasing factor (CRF), in the mesocorticolimbic reward pathway enhanced the reinforcing effects of nicotine. The latter effect was greater in female versus male rats, suggesting that females are uniquely susceptible to the effects of stress on nicotine reinforcement. The goal of this dissertation was to examine the neurochemical mechanisms by which overexpression of CRF in the nucleus accumbens (NAc), a terminal region of the mesocorticolimbic pathway, modulates the behavioral effects of nicotine. Specifically, we examined whether nicotine-induced dopamine levels are altered by CRF overexpression via excitatory (glutamate) …

Brian Valdez - Dynamics And Control Of A 3-Dof Manipulator With Deep Learning Feedback, Brian Orlando Valdez

Open Access Theses & Dissertations

With the ever-increasing demands in the space domain and accessibility to low-cost small satellite platforms for educational and scientific projects, efforts are being made in various technology capacities including robotics and artificial intelligence in microgravity. The MIRO Center for Space Exploration and Technology Research (cSETR) prepares the development of their second nanosatellite to launch to space and it is with that opportunity that a 3-DOF robotic arm is in development to be one of the payloads in the nanosatellite. Analyses, hardware implementation, and testing demonstrate a potential positive outcome from including the payload in the nanosatellite and a deep learning …

A Comprehensive And Modular Robotic Control Framework For Model-Less Control Law Development Using Reinforcement Learning For Soft Robotics, Charles Sullivan

Open Access Theses & Dissertations

Soft robotics is a growing field in robotics research. Heavily inspired by biological systems, these robots are made of softer, non-linear, materials such as elastomers and are actuated using several novel methods, from fluidic actuation channels to shape changing materials such as electro-active polymers. Highly non-linear materials make modeling difficult, and sensors are still an area of active research. These issues have rendered typical control and modeling techniques often inadequate for soft robotics. Reinforcement learning is a branch of machine learning that focuses on model-less control by mapping states to actions that maximize a specific reward signal. Reinforcement learning has …

Spatially Adaptive Estimation Of Spectrum, Yi None Xie

Open Access Theses & Dissertations

When analyzing a stationary time series, one of the questions we are often interested in is how to estimate its spectrum. Many approaches have been proposed to this end. Most are focused on smoothing the periodogram using a single smoothing parameter across all Fourier frequencies. In this paper, we smooth the log periodogram by placing a spatially adaptive prior called the dynamic shrinkage prior, so that varying degrees of smoothing may be applied to different intervals of Fourier frequencies, resulting in less biased estimates of the spectrum. Further research will extend this approach to spectral estimation for nonstationary time series.

Antioxidant Intervention In Radical-Induced Protein Damage, Emmanuel Zubia

Open Access Theses & Dissertations

Many environmental toxicants are known to increase free-radical production, which can create cellular havoc and lead to a myriad of ailments. Antioxidants can be used to ameliorate the prevalence of free radicals, potentially serving as prophylactics against radical-induced disorders. Many exogenous antioxidants are phytochemicals in origin, such as ascorbic acid, gallic acid, and ellagic acid. Some of these antioxidants can be found in traditional medicine, like tanshinone and brazilin, which have been studied and are known to have low cytotoxicity. Here we test the radical rescue capacity of a selected group of phytochemical antioxidants on protein rescue models. Specifically, our …

Using Visual Prompts In Research, Maura A. Smale, Mariana Regalado

Publications and Research

No abstract provided.