Digital Commons Network^™

Process Monitoring In Additive Manufacturing Aimed Toward Part Qualification, Shakerur Ridwan

Open Access Theses & Dissertations

Additive Manufacturing (AM), or layer-by-layer part fabrication, has played a tremendous role in the maker culture by allowing ideas to be materialized with limited resources or knowledge in manufacturing. Various cutting edge AM technologies exist today that are used to create end-use parts; however, these technologies are still new and the processes have not gone through the rigorous evaluation process that traditional manufacturing (i.e. milling, stamping, casting) methods have been through. As a result, several important questions arise when looking to adapt AM technology, including control of the manufacturing process, effect of manufacturing process on part properties, level of variance …

Processing Of Language Switches In Bilingual Individuals With Aphasia: An Event-Related Potential Comparison, Lizette Rodarte

Open Access Theses & Dissertations

Switching between languages, or code-switching, is a common phenomenon in bilingual individuals. In proficient bilinguals, these switches are done with ease and are used for many purposes. Contrary to popular belief, these switches are rule-governed and follow grammatical structure. Bilingual individuals diagnosed with aphasia present with difficulty processing languages and these language switches. With the increase in bilingual individuals, it is likely that the speech-language pathology community will see an increase of bilingual individuals with aphasia on their caseload. For this reason, the purpose of this study is to increase our understanding of the neural processes involved in processing of …

Carbon Based Nano-Composite Materials For Energy Storage Applications, Gerardo Rodriguez Melo

Open Access Theses & Dissertations

Energy storage systems and devices are an integral part of advanced electronic technology. Electronic technology is ever-advancing, but in order to do so, it must be supported by all its systems. The energy storage system is one key system that may dictate the performance and limitation of such electronics. Thus, research emphasis on energy storage devices has been on improving the performance of energy storage devices, such as: improved energy and power density, increased stability and cycle life, as well as reduced costs. Lithium-ion-batteries, and supercapacitors offer the potential to meet energy storage demands and to be improved further upon. …

Visual Arts Teacher Preparation, Lucina Rodriguez Zarate

Open Access Theses & Dissertations

Studies have found that visual arts education is an essential part of students' overall educational development. Students exposed to a robust visual arts education develop critical and analytical thinking skills, learn to evaluate their own work and the work of their peers, learn to interpret subject matter in various ways, and are encouraged to engage in their community, all of which help students develop a higher self-esteem and create a positive attitude towards learning. However, to achieve such positive results, visual arts educators need to acquire the proper training to learn how to develop and deliver well-rounded curricula with the …

Neighbor Discovery In Mobile Ad Hoc Networks, Esau Enrique Ruiz-Gaistardo

Open Access Theses & Dissertations

Neighbor Discovery (ND) is the process that initializes a reliable communication between one-hop neighbors in mobile ad hoc networks (MANETs). This process consists of scheduled exchanges of control messages, called â??Hello Messagesâ?? (HMs) between one-hop neighbors. HMs build bidirectional links that are used to announce the topology information. Each node uses ND and the topology information to populate its routing tables and to communicate with every other node in the network. In MANETs, ND process is a permanent process to discover one-hop neighbors. It is based on two parameters: 1) ND message interval (the period of time in between sending …

Microscopic And Spectroscopic Analysis Of Cadmium Telluride, Jessica Goretty Salazar

Open Access Theses & Dissertations

Cadmium telluride (CdTe) remains one of the materials of interest in the fabrication of photovoltaic cells and infrared devices, mainly because of its suitable crystal structure as well as of its small, direct bandgap of 1.5 eV. Since development of such devices requires a high quality and low defect material, the goal of this study is to microscopically and spectroscopically examine not only crystallinity, but also the induced stress in the material due to the effect of substrate orientation. This information is valuable if optimization of sample growth conditions is envisioned. Prior to CdTe deposition by close-spaced sublimation (CSS), Si …

Mobile Professional Development: Taxonomic Levels Of Learning On Teachers' Tpack Perceptions And Acquisition Of Technology Competencies, Raul Saldana Jr.

Open Access Theses & Dissertations

As it stands, the integration of technology can be advantageous for teachers, students, administrators, and parents, yet teachers are expected to teach and facilitate learning with new technologies in order to prepare students to succeed in a global economy. As the Part D of the Enhancing Education Through Technology Act of 2001 (Part D - Enhancing Education Through Technology, n.d) states, one of its purposes is to "enhance ongoing professional development of teachers, principals, and administrators by providing constant access to training and updated research in teaching and learning through electronic means," one of its goals is to "encourage effective …

Dating Across Difference: A Rhetorical Analysis Of Interracial Same-Sex Relationships In Targeted Media Outlets, Victor Santana-Melgoza

Open Access Theses & Dissertations

The purpose of this study is to examine how interracial same-sex relationships are constructed and communicated within gay themed media outlets, specifically magazine publications, and the possible effects such construction may have on various consumer populations through the frame of cultivation theory. I studied three major gay publications and surveyed 90 articles for both textual content and visual representation. Categories were then created and articles were grouped by relevance to each category. Through iterative processes, the number of useable articles fell to 68. Articles were mainly captured using online sources. Through this medium of online reading, other access points were …

A Geophysical Study Of The Castle Mountain Fault System And Matanuska-Susitna Valley Near Anchorage, Alaska, Shane Michael Schinagel

Open Access Theses & Dissertations

The Castle Mountain Fault (CMF) is the closest (~50 km) active fault to Anchorage, Alaska. Located within the Matanuska and Susitna (Matsu) Valleys, the CMF shows repeated, unmistakable evidence for Holocene motion. Recent geologic studies estimate that this fault is capable of producing earthquakes of magnitude 7.0 - 7.1. The Anchorage metropolitan area (which includes the Matsu Valley) contains most of Alaska's population as well as vital shipping and transportation facilities that serve much of inland Alaska. Expected magnitude >7 earthquakes pose seismic hazards to the expanding Anchorage area.

While several mapping and trenching studies have been conducted along the …

Heat Absorption Analysis By Falling Particles At High Temperatures For Concentrating Solar Power Systems, Arturo Sepulveda Fernandez

Open Access Theses & Dissertations

High temperature Heat Transfer Fluid (HTF) with Thermal Energy Storage (TES) for the Concentrated Solar Power (CSP) technology can provide a large and relatively cheaper storage option, as opposed to limited and expensive electrical battery storage with PV technology, and hence, it has potential to maintain a constant production when no sunlight is available. Research of material like aluminum, silicon, graphite could be potential candidates to work as thermal energy storage. Currently, nitrate and chloride molten salts are widely used as the TES medium for a CSP plant. However, molten salt, especially chlorides, must be handled carefully at high temperature …

A House All White And Empty Against The Night Sky, Jesus J. Silveyra

Open Access Theses & Dissertations

Not available.

High School Students' And Scientists' Perceptions Of A Student-Scientist Partnership, Karla Singh

Open Access Theses & Dissertations

The idea of getting high school students to work with scientists has become a hot topic. There have been many programs that get students involved with scientists to gain experience. Having students work with scientists allows students to practice authentic science. These programs also aim to get more students interested in science and hopefully inspire these students to go into a science career. Researchers have looked at several aspects during these interactions. These aspects include students' interest, students' ability, students' career choice and students' perceptions of the scientific community. However, few studies are known that include trying to understand students' …

Tiger Shell, Christopher Sinnett

Open Access Theses & Dissertations

Poetry is everything. A poem is a shell filled with a sliver of poetry. Life goes in, life comes out. These shells are filled with what we know, and deep inside, what we do not know. The ocean goes in and out. Art is in the shell. The poet enters, does not perform, does not act, does not do. The poet is.

A Bayes Approach In Step-Stress Accelerated Life Testings, Hao Yang Teng

Open Access Theses & Dissertations

A Bayesian analysis for the Weibull proportional hazard (PH) model is presented. A comparison between the Weibull PH model and the Weibull cumulative exposure (CE) model is made graphically and mathematically. The PH model is as flexible as the CE model in fitting step-stress data and the mathematical form of the PH model enables researchers to do Bayesian inferencemuch easier than the CE model. In addition, the PH model has the desirable proportional hazard property. A convex tent prior is used for Bayesian analysis. Markov chain Monte Carlo methods are used for posterior inferences. In this study, we adopt two …

"Es Que Nadie Me Quiere Ayudar," Affective Factors In The Schooling Experience Of Recent Immigrants And Dual Language Instruction, Maria Del Rosario Talamantes

Open Access Theses & Dissertations

This Dissertation is a critical ethnography of the schooling experiences of recent immigrants in dual language immersion classes in US schools where the separation of languages is a policy (Adelman Reyes, 2007; Collier & Thomas, 2004; Cummins, 2005; Lee et al., 2008). Under this program, language is said to be used as a resource to motivate learning among students working in cooperative groups (Gomez, Freeman & Freeman, 2005; Kagan, 1995; Ruiz, 1984). However, this study revealed that language was also used as a tool for oppression among recent immigrant students (Bakhtin, 1981; Giltrow, 2003; Heller, 1995). Focusing on recent immigrant …

Stochastic Differential Equation Applied To High Frequency Data Arising In Geophysics And Other Disciplines, Osei Kofi Tweneboah

Open Access Theses & Dissertations

Estimating future seismic hazards of a region constitutes an important study many scholars have shown a renewed interest in the past few decades. A good estimation of the seismic hazard in a region requires predicting the location and magnitude of future seismic events. As the knowledge of the geophysical mechanisms that drive seismic events have increased, so have the corresponding mathematical model representations.

This Thesis is devoted to the study of modeling geophysical data. We propose a stochastic differential equation arising on the superposition of independent Ornstein-Uhlenbeck processes driven by a Gamma process.

Superposition of independent Gamma Ornstein-Uhlenbeck processes offers …

Single And Multiple Objective Biomass-To-Biofuel Supply Chain Optimization Considering Environmental Impacts, Claudia Evangelina Valles Sosa

Open Access Theses & Dissertations

Bioenergy has become an important alternative source of energy to alleviate the reliance on petroleum energy. Bioenergy offers diminishing climate change by reducing Green House Gas Emissions, as well as providing energy security and enhancing rural development. The Energy Independence and Security Act mandate the use of 21 billion gallons of advanced biofuels including 16 billion gallons of cellulosic biofuels by the year 2022. It is clear that Biomass can make a substantial contribution to supply future energy demand in a sustainable way. However, the supply of sustainable energy is one of the main challenges that mankind will face over …

The Impact Of Accented English On Speech Comprehension, Benigno Valles

Open Access Theses & Dissertations

ABSTRACT

In the context of shifting demographics in the United States and with an increasing multicultural workforce, the verbal exchange of information is vital especially between health care providers and patients. Although English is the official language in the United States, many individuals from different national origins speak English with some degree of accent. Before we can address health care provider/patient communication, it is necessary to investigate the potential impact of accented English on speech comprehension and its implications on basic communicative interactions. The verbal exchange of information between health care providers and patients is important in diagnostics, treatment, patient …

Development Of A Novel Hybrid Unified Viscoplastic Constitutive Model, Luis Alejandro Varela Jimenez

Open Access Theses & Dissertations

Gas turbines are now days used in power plants for power generation and for propulsion in the aerospace industry. In these applications gas turbines are exposed to severe temperature and pressure variations during operating cycles. These severe operating conditions exposed the turbineâ??s components to multiple deformation mechanisms which degrade the material and eventually lead to failure of the components. Nickel based and austenitic super alloys are candidate material used for these applications due to its high strength and corrosion resistance at elevated temperatures. At such temperature levels, candidate materials exhibit a rate-dependent or viscoplastic behavior which difficult the prediction or …

No Longer Mourn, Riley Welcker

Open Access Theses & Dissertations

This novel is a coming-of-age story about a young woman named Eva who searches for the truth about her father's murder and in the process discovers more about herself than she could foresee. Intending to confront the man who murdered her father, she flies from her home in Norway to the State Correctional Institution in Idaho, but what she learns is totally unexpected. In an attempt to navigate her prejudice against him, the man tells a dual story that reveals his history with her parents and the dramas of a past she never knew. She then receives the shock of …

Pre-Tuned Ridge Regression And Its Extension To Generalized Linear Models, Yaa Tawiah Wonkye

Open Access Theses & Dissertations

Ridge regression is regularization or shrinkage method and a common approach in dealing with multicollinearity in conventional regression analysis. Ridge regression is widely used by statistical analyst since it is one of the best compared to other regularization methods. Also, the introduction of high dimension and ultra-high dimensional data has become an issue of concern and ridge regression is one way of dealing with such data. One of the key issues associated with ridge regression is the determination of the tuning or ridge parameter. The common practice is to fit ridge regression for a different number of values of tuning …

Monitoring And Understanding Decadal Scale Changes In Hydrology, Productivity And Carbon Balance In Arctic Tundra Ponds, Christian Gerardo Andresen

Open Access Theses & Dissertations

The Arctic is known for containing large stocks of soil organic carbon, which exists frozen in permafrost in a greenhouse inert state. With predicted future warming in these high northern latitudes, the mobilization of stored soil organic carbon and release to the atmosphere may increase and induce further positive climatic feedbacks. Previous studies have shown that Arctic wetlands and ponds cover a large percentage of the Arctic Coastal Plain and contribute large amounts of carbon to the atmosphere; however, it remains largely unknown how these systems are responding to a warming climate and how this change will impact regional carbon …

Harbor Security System, Timothy Jonathan Brown, Matthew Birkebak

Honors Theses and Capstones

Harbors and ports provide the infrastructure for commercial trade and naval facilities. It is vital to ensure the safety of these locations. The Harbor Security System provides an optical ‘gate’ using underwater lasers and photodetectors. This system allows monitoring of both surface and submarine vessels traveling into and out of the harbor. Also, the system provides real time alerts when unauthorized vessels enter the harbor. This project provides a proof of concept for a Harbor Security System to be implemented in Portsmouth Harbor. A scaled model of the detection system was constructed and tested. This detection system is capable of …

Effects Of Gravity On The Acceleration And Pair Statistics Of Inertial Particles In Homogeneous Isotropic Turbulence, H. Parishani, O. Ayala, B. Rosa, L.-P. Wang, W. W. Grabowski

Engineering Technology Faculty Publications

Within the context of heavy particles suspended in a turbulent airflow, we study the effects of gravity on acceleration statistics and radial relative velocity (RRV) of inertial particles. The turbulent flow is simulated by direct numerical simulation (DNS) on a 256³ grid and the dynamics of O(10⁶) inertial particles by the point-particle approach. For particles/droplets with radius from 10 to 60 µm, we found that the gravity plays an important role in particle acceleration statistics: (a) a peak value of particle acceleration variance appears in both the horizontal and vertical directions at a particle Stokes number …

Effects Of Forcing Time Scale On The Simulated Turbulent Flows And Turbulent Collision Statistics Of Inertial Particles, B. Rosa, H. Parishani, O. Ayala, L.-P. Wang

Engineering Technology Faculty Publications

In this paper, we study systematically the effects of forcing time scale in the large-scale stochastic forcing scheme of Eswaran and Pope ["An examination of forcing in direct numerical simulations of turbulence," Comput. Fluids 16, 257 (1988)] on the simulated flow structures and statistics of forced turbulence. Using direct numerical simulations, we find that the forcing time scale affects the flow dissipation rate and flow Reynolds number. Other flow statistics can be predicted using the altered flow dissipation rate and flow Reynolds number, except when the forcing time scale is made unrealistically large to yield a Taylor microscale flow Reynolds …

Uneven Experiences: The Impact Of Student-Faculty Interactions On International Students' Sense Of Belonging, Chris R. Glass, Elizabeth Kociolek, Rachawan Wongtrirat, R. Jason Lynch, Summer Cong

Educational Leadership & Workforce Development Faculty Publications

This study examines student-faculty interactions in which U.S. professors signal social inclusion or exclusion, facilitating–or inhibiting–international students’ academic goal pursuits. It compares narratives of 40 international students from four purposefully sampled subgroups – academic preparedness (low, high) and financial resources (low, high). Overall, international students’ interactions with professors were marked by joy, trust, anticipation, and surprise. Nonetheless, the narratives exhibit two significant sources of variation: narratives from the low financial resources, high academic preparedness subgroup reflected widely-varied experiences interacting with professors, and narratives from the low financial, low academic preparedness subgroup lacked any descriptions of positive student-faculty interactions.

Self-Reported Experiences Of Climate Change In Nigeria: The Role Of Personal And Socio-Environmental, Idowu Ajibade, Frederick Ato Armah, Vincent Kuuire, Isaac Luginaah, Gordon Mcbean

Geography Faculty Publications and Presentations

In this study, we examined the individual and socio-environmental factors that mediate differential self-reported experiences of climate change in coastal communities in Lagos, Nigeria. Binary complementary log-log multivariate regression was used to model residents’ experiences of changing rainfall patterns, ocean surges, and flood events. An analysis of both compositional and contextual factors showed that there were urban communities where vulnerability to flooding tends to be clustered, and that this was not fully explained by the characteristics of the people of whom the community was composed. This study, thus, underscores the importance and complex nature of the interaction between personal and …

Factors Affecting Unsatisfactory Performance During Air-To-Air Refueling In The C-17 Pilot Checkout Course, Richard Smith

Theses and Dissertations

In 2014, the USAF reduced its personnel by approximately 20,000. One of the areas hit hardest by the cuts were the faculty at the USAF C-17 formal training unit, where students are trained to fly the C-17 transport plane. Due to the reduction in forces, faculty staffing dropped by 30% though the number of students remained the same. Air-to-air refueling during the Pilot Checkout Course is the most commonly failed syllabus event. When a student fails to progress on a syllabus event, it requires additional instructor, simulator, and aircraft resources. In an effort to reduce the amount of failures and …

Recall Of Novel Words In Adolescents Following A Brief Mindfulness Exercise, Anna Lauren Schimmelpfennig

Theses and Dissertations

Mindfulness has been associated with various benefits, including enhanced attention, improved recall, and increased emotional well-being. Previous research has suggested that a brief mindfulness exercise can enhance recall of novel words in female college students. Participants in the current study were 82 students (41 female, M = 14.6, SD = 1.2) from a rural, Midwestern secondary school. Participants were randomly assigned to listen to a 20-minute body scan exercise or a control lecture before learning English-Swahili word pairs. Results revealed no significant effect of group on immediate or delayed recall of word pairs. Additionally, there was no significant effect of …

Local Buckling Restraining Behavior Of Concrete-Filled Steel Tubular Columns Under Seismic Loads, Fokruddin Ahmad

Theses and Dissertations

Extensive investigations have verified that frame systems consist of concrete-filled steel tubular (CFST) columns have more benefits than ordinary reinforced concrete and steel systems. The CFST column increases earthquake resistant capabilities due to the concrete filling inside the steel tubes and are ideal for buildings subjected to large compressive stress. The use of CFST columns is drawing attention due to their strength and quake-proof advantages. Local buckling of the steel tube is delayed by the restraint of the concrete, and the strength of concrete is increased by the confining effect of the steel tube.

This thesis deals with the local …