Digital Commons Network^™

Effect Of Process Variables On Sub-Melt Thermal Behavior And Solid-State Phase Transformations In Beam-Based Additive Manufacturing Of Ti-6al-4v, Heather N. Doak

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The success of laser and electron beam-based fabrication processes for additive manufacture and repair applications requires the ability to control melt pool geometry while maintaining a consistent and desirable microstructure. Previous work has employed a process map approach to link melt pool geometry to solidification microstructure (grain-size and morphology) in beam-based fabrication of Ti-6Al-4V. The current work extends the approach to investigate the effects of process variables on solid-state phase transformations below the solidification temperature through Finite Element Modeling, the 3-D Rosenthal Solution, and experimentation. Process maps for solid-state microstructure could be used to help maintain consistent and reliable mechanical …

An Accuracy Improvement Method For Cricket Indoor Location System, Anall Vijaykumar Gandhi

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The effective deployment of Automated Guided Vehicles (AGV) in indoor hostile environment demands high precision localization for navigation purposes. The cricket system, based on Time Difference of Arrival (TDoA) approach, provides precise localization. It calculates TDoA between radio and ultrasonic signal to estimate distance between two cricket motes. The position, in the referenced coordinate system, is estimated by multilateration using estimated distances from multiple motes. Therefore, the position accuracy depends on the distance estimation which in turn depends on the TDoA calculation. Ultrasonic transducer, a component of cricket mote hardware, has highly directive radiation pattern which affects ultrasonic signal detection. …

Design And Improve Energy Efficiency And Functionalities Of Electrical Wheelchairs, Dewei Guan

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There are millions of people who have lost their abilities to walk and wheelchairs offer the ONLY opportunities for their interactions with people and environments outside their houses. These individuals are becoming more and more eager to adapt modern technologies on their wheelchairs to improve quality of social life and the life of freedom. However, most available electric wheelchairs, driven by traditional lead-acid batteries and gear motors, are heavy and bulky in design with low energy efficiency, limited travel radius, and scarce communication/navigation functionalities. This project is to design and prototype an electric wheelchair that is lighter, more flexible in …

An Experimental Investigation On The Control Of Tip Vortices From Wind Turbine Blade, Zhe Ning

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Wind turbine dynamics, wake effects and environmental impacts have been identified the most significant research topics needed for wind resource characterization and wind power generation. Among these issues, tip vortices generated from the blade tip have been recognized as a substantial resource for the turbulent wake flow as well as the aerodynamic noise emission from a wind turbine. An experimental study is conducted to characterize the evolution of the tip vortices downstream of a well-designed horizontal axis wind turbine (HAWT) model. In addition to measuring dynamic wind loads (both aerodynamic forces and moments) and power output from the wind turbine …

Overview Of The Large-Scale Biosphere–Atmosphere Experiment In Amazonia Data Model Intercomparison Project (Lba-Dmip), Luis Gustavo Goncalves De Goncalves, Jordan Borak, Marcos Heil Costa, Scott R. Saleska, Ian Baker, Natalia Resprepo-Coupe, Michel Nobre Muza, Benjamin Poulter, Hans Verbeeck, Joshua B. Fisher, Altaf Arain, Phillip Arkin, Bruno P. Cestaro, Bradley Christoffersen, David Galbraith, Xiaodan Guan, Bart Van Den Hurk, Kazuhito Ichii, Hewlley Acioli Imbuzeiro, Atul Jain, Naomi Levine, Chaoqun Lu, Gonzalo Migues-Macho, Debora Roberti, Alok Sahoo, Koichi Sakaguchi, Kevin Shaefer, Mingjie Shi, James Shuttleworth, Hanqin Tian, Zong-Lian Yang, Xubin Zeng

United States National Aeronautics and Space Administration: Publications

A fundamental question connecting terrestrial ecology and global climate change is the sensitivity of key terrestrial biomes to climatic variability and change. The Amazon region is such a key biome: it contains unparalleled biological diversity, a globally significant store of organic carbon, and it is a potent engine driving global cycles of water and energy. The importance of understanding how land surface dynamics of the Amazon region respond to climatic variability and change is widely appreciated, but despite significant recent advances, large gaps in our understanding remain. Understanding of energy and carbon exchange between terrestrial ecosystems and the atmosphere can …

Reassessment Of The Classical Closures For Scalar Turbulence, Robert Rubinstein, Timothy T. Clark

United States National Aeronautics and Space Administration: Publications

In deducing the consequences of the Direct Interaction Approximation, Kraichnan was sometimes led to consider the properties of special classes of nonlinear interactions in degenerate triads in which one wavevector is very small. Such interactions can be described by simplified models closely related to elementary closures for homogeneous isotropic turbulence such as the Heisenberg and Leith models. These connections can be exploited to derive considerably improved versions of the Heisenberg and Leith models that are only slightly more complicated analytically. This paper applies this approach to derive some new simplified closure models for passive scalar advection and investigates the consistency …

Spurious Behavior Of Shock-Capturing Methods By The Fractional Step Approach: Problems Containing Stiff Source Terms And Discontinuities, Helen C. Yee, D. V. Kotov, Wei Wang, Chi-Wang Shu

United States National Aeronautics and Space Administration: Publications

The goal of this paper is to relate numerical dissipations that are inherited in high order shock-capturing schemes with the onset of wrong propagation speed of discontinuities. For pointwise evaluation of the source term, previous studies indicated that the phenomenon of wrong propagation speed of discontinuities is connected with the smearing of the discontinuity caused by the discretization of the advection term. The present study focuses only on solving the reactive system by the fractional step method using the Strang splitting. Studies shows that the degree of wrong propagation speed of discontinuities is highly dependent on the accuracy of the …

Corrigendum To ‘‘Spurious Behavior Of Shock-Capturing Methods By The Fractional Step Approach: Problems Containing Stiff Source Terms And Discontinuities’’ [J. Comput. Phys. 241 (2013) 266–291], Helen C. Yee, Dmitry V. Kotov, Wei Wang, Chi-Wang Shu

United States National Aeronautics and Space Administration: Publications

This corrigendum contains a correction to some of the figures in the article ‘‘Spurious behavior of shock-capturing methods by the fractional step approach: Problems containing stiff source terms and discontinuities’’ [J. Comput. Phys. 241 (2013) 266–291]. There was a computer coding error in the computer code that generates the results. The coding error consists of failing to update the temperature from the final solution of the RK4 convection step time evolution before the reaction step using the Strang splitting in Eq. (29). In addition, if N_r > 1, the error includes no update to the temperature for each sub-iteration on …

The Dog Days Fourth Amendment Jurisprudence, Kit Kinports

Faculty Scholarship

This Article discusses Florida v. Harris and Florida v. Jardines, the two Fourth Amendment drug dog opinions issued by the Supreme Court earlier this year. Together the cases hold that a narcotics detection dog effects a “search” when it intrudes on a constitutionally protected area in order to collect evidence, but that the dog’s positive alert is generally sufficient to support a finding of probable cause. The piece argues that both cases essentially generate a bright-line rule, thereby deviating from precedent that favored a more amorphous standard considering all the surrounding circumstances. Like many purportedly clear rules, the ones …

Sexual Orientation Of Fatherhood, Dara Purvis

Faculty Scholarship

In this Article, I examine how same-sex fathers affect the perception of heterosexual caretaking fathers - and by extension, could affect the perception of heterosexual non-caretaking mothers. I conclude that gay stay-at-home fathers offer a provocative opportunity to broaden societal views of men and caregiving more generally, and argue that greater recognition of parents who counteract gender stereotypes - even where the recognition might arguably lessen women's rights in family law - ultimately helps women as well as children and nontraditional parents. Part I discusses fathers, particularly stay-at-home fathers, the practical problems fathers face combining work and caregiving responsibilities, and …

The Opportunity Costs Of Ignoring The Law Of Sea Convention In The Arctic, James W. Houck

Faculty Scholarship

The paper begins by briefly surveying the extent to which the convention’s provisions intersect with United States interests in the Arctic. Not surprisingly, there is extensive overlap. The paper then reviews arguments that UNCLOS is irrelevant or even antithetical to achieving these important U.S. interests. After critiquing the anti-UNCLOS arguments, the paper examines the case for UNCLOS. The paper focuses in particular on U.S. interests on the Arctic seafloor, arguing that these interests are extensive and that accession would help avert a wide range of potential political, legal, and regulatory challenges from foreign governments and corporations. The possibility of such …

Embracing The Queen Of Hearts: Deference To Retroactive Tax Rules, James M. Puckett

Faculty Scholarship

The Supreme Court’s decision in Mayo Foundation for Medical Education and Research v. United States underscored the importance of a uniform approach to judicial review of administrative action; accordingly, the Court clarified that tax administration is generally subject to the same review as other kinds of administrative action by other federal agencies. Tax guidance from the IRS and Treasury Department serves an important role in clarifying the tax law so that taxpayers may report their tax liability accurately and plan their affairs. Meanwhile, aggressive attempts by a relatively small number of taxpayers to avoid tax liability by exploiting arguable ambiguities …

Protecting Pedagogical Choice: Theory, Graphic Novels, And Textual Complexity, Lisa Schade Eckert

Language Arts Journal of Michigan

No abstract provided.

Adaptive Semantic Annotation Of Entity And Concept Mentions In Text, Pablo N. Mendes

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The recent years have seen an increase in interest for knowledge repositories that are useful across applications, in contrast to the creation of ad hoc or application-specific databases.

These knowledge repositories figure as a central provider of unambiguous identifiers and semantic relationships between entities. As such, these shared entity descriptions serve as a common vocabulary to exchange and organize information in different formats and for different purposes. Therefore, there has been remarkable interest in systems that are able to automatically tag textual documents with identifiers from shared knowledge repositories so that the content in those documents is described in a …

The Effects Of The Proportion Of Women In A Work Role And Tenure On Performance, Kathryn Gabrielle Van Dixhorn

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Token theory (Kanter, 1977) suggests that being a token individual in an organization can cause that individual to experience discrimination, increased pressure to perform, isolation from the majority group, negative stereotyping, and can interfere with performance. The purpose of this research was to determine if varying percentages of females in a work role do indeed influence the likelihood that these negative outcomes will occur by using performance data from an applied sample. By using both supervisor ratings and objective sales figures from a sales organization, this research filled a gap in the current research, in which token theory is often …

Expressing Future Time In Spoken Conversational English: A Corpus-Based Analysis Of The Sitcom Friends, Brandon Harris

Electronic Theses and Dissertations

Far from being simply will, a survey of English grammar textbooks revealed that a multitude of expressions exists in the English language to express the future time. These expressions include, but are not limited to, will, be going to, the simple present tense, modals, the future perfect tense, and the present progressive tense. With so many choices and with a lack of direct relationship between tense and time, a language learner may certainly have difficulties in choosing which expression to use when attempting to produce a future utterance. A corpus-based approach to analyzing real language has been demonstrated to be …

Parental Beliefs And Attitudes On Enrollment In A Dual Language Program At An Elementary School, Leah Delorenzo

Electronic Theses and Dissertations

In the 2010-2011 school year, there were almost a quarter of a million English language learners (ELLs) enrolled in Florida public schools (Florida Department of Education, 2011), most of whom were placed in mainstream schools with segregated language remediation. Dual language education (DLE) programs offer developmental opportunities in two languages that mainstream schools cannot. The purpose of this research was to identify parental attitudes toward immersion programs and define the reasons that parents enroll their children in DLEs. Sixty participants completed a questionnaire sent home from their student's DLE. The study data included biographical information, statements depicting the reasons for …

The Effect Of Input Modality On Pronunciation Accuracy Of English Language Learners, Marcella A. Farina Phd

Electronic Theses and Dissertations

The issues relative to foreign accent continue to puzzle second language researchers, educators, and learners today. Although once thought to be at the root, maturational constraints have fallen short of definitively accounting for the myriad levels and rates of phonological attainment (Bialystok & Miller, 1999, p. 128). This study, a Posttest-only Control Group Design, examined how the pronunciation accuracy of adult, English language learners, as demonstrated by utterance length, was related to two input stimuli: auditory-only input and auditoryorthographic input. Utterance length and input modality were further examined with the added variables of native language, specifically Arabic and Spanish, and …

Synthesis And Electrodeposition Of Mixed Metal Trinuclear Clusters Of Molybdenum And Chromium In Ionic Liquid Onto A Platinum Electrode, Lynn Renee Frock

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Electrochemical properties of [Mo3O2(O2CCH3)6(H2O)(CF3SO2H)2 and [Cr2Mo(u2-CH3COO)6(u3-O)(H2O)3][CF3SO3] in 1-ethyl-3-methylimidazolium bis(pentafluoroethanesulfonyl)-imide ionic liquid was investigated. Cyclic voltammograms using a Platinum electrode indicated deposition had occurred for the [Mo3O2(O2CCH3)6(H2O)(CF3SO2H)2 metal cluster but had not for the polynuclear complex [Cr2Mo(u2-CH3COO)6(u3-O)(H2O)3][CF3SO3]. Constant potential electrolysis of -1.23 V using a platinum foil electrode was performed. Scanning electron microscopy in combination with energy dispersion spectroscopy confirmed that deposition had occurred.

Role Of Bax, Ibpa, Ibpb And Csph Genes In Protecting Cft073 (Uropathogenic Escherichia Coli) Against Salt And Urea Stress, Pavani Beesetty

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Uropathogenic Escherichia coli (UPEC) are the primary cause of 80 to 90% of uncomplicated urinary tract infections. After entering the urinary tract, uropathogenic E.coli has to tolerate high levels of salt and urea in urine to cause a successful infection. The osmotic stress imposed by urea is different from that by NaCl, as urea can freely move across the cell membrane and is a protein denaturant. Hence, microarray experiments were performed to observe the differential expression of genes in CFT073 (UPEC) due to the presence of 0.3 M NaCl and 0.6 M urea in K medium individually. Based on the …

Effect Of Rat Strain Stereotactic Coordinates On Infarct Volume, Saagar K. Sanghvi

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Ischemic stroke makes up 87% of all hospital-admitted stroke cases annually; the primary treatment for these cases is intravenous administration of tPA within a 3.5 hour window from stroke onset. A long-term delayed ischemic stroke treatment proposed by this study was a combination of the pharmaceuticals Fluoxetine (SSRI), Simvastatin (statin), and ascorbic acid (Vitamin C). 51 adult rat subjects (10-12 months of age; 44 Sprague Dawley, 7 Long Evans) were given a combination of the drugs for 31 days. Drugs were given through voluntary oral administration via sugar cookie-dough balls to reduce inhibition of neurogenesis through stress-related glucocorticoid production. Drug …

Spectrally Modulated Spectrally Encoded Framework Based Cognitive Radio In Mobile Environment, Xue Li

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Radio spectrum has become a precious resource, and it has long been the dream of wireless communication engineers to maximize the utilization of the radio spectrum. Dynamic Spectrum Access (DSA) and Cognitive Radio (CR) have been considered promising to enhance the efficiency and utilization of the spectrum. Since some of the spectrum bands are occupied by primary users (PUs), the available spectrum for secondary users (SUs) are non-contiguous, and multi-carrier transmission technologies become the natural solution to occupy those non-contiguous bands. Non-contiguous multi-carrier based modulations, such as NC-OFDM (non-contiguous Orthogonal Frequency Division Multiplexing), NC-MC-CDMA (non-contiguous multi-carrier code division multiple access) …

The Power Of Perception: Securitization, Democratic Peace, And Enduring Rivalries, Derrick Charles Seaver

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What best explains the democratic peace: empirical indicators of democracy or the mutual perceptions of democracy within a dyadic relationship? This paper will examine three enduring rivalry dyads: the United States-Great Britain, France-Germany, and India-Pakistan, during the course of their respective enduring rivalries (Bennett, 1997; Diehl and Goertz, 2000). Within each of these dyads, I will provide detailed case studies of two conflicts at different phases of democratization - six cases in total - in order to ascertain the answers to three questions: 1) What role, if any, did the democratic character of the individual governments play in the resolution …

Relationships Among Employee Engagement, Communication Climate, And Employees' Communication Channel Preferences, Jessica Roberts

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The purpose of this research was to determine the relationship among communication climate, employee engagement and employees' communication channel preferences. The research established a moderate relationship among communication climate and employee engagement. Although this finding aligns with the current literature, the study failed to establish a relationship between employee engagement and employees' communication channel preferences. The research did document that the top three communication channels for employees of all levels of engagement are face to face, email and poster/flyers/brochures. While Chapter 2 reviewed past literature of communication climate, employee engagement and communication channel preferences it was noted that there is …

The Solvent-Free Synthesis Of And N-Methyl-N-Alkylpiperidinium Salts And Their Anion Exchange Reactions With Dilithium Phthalocyanine, Michael Joseph Krol Jr.

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A nucleophilic substitution reaction of N-methylpiperidine with bromopropane, bromobutane, bromopentane, bromohexane and bromoheptane was carried out in a Q-Tube with excess alkyl halide and yielded N-methyl-N-propylpiperidinium bromide, N-methyl-N-butylpiperidinium bromide, N-methyl-N-pentylpiperidinium bromide, N-methyl-N-hexylpiperidinium bromide and N-methyl-N-heptylpiperidinium bromide in yields from 85 to 92 %. The salts, which were solids at room temperature, were soluble in dichloromethane and were characterized by 1H and 13C NMR, elemental analysis and DSC. Two of the piperidinium bromides, N-methyl-N-propylpiperidinium bromide, N-methyl-N-butylpiperidinium bromide were used in an anion exchange reaction with dilithium phthlocyanine to yield N-methyl-N-propylpiperidinium lithium phthalocyanine and N-methyl-N-butylpiperidinium lithium phthalocyanine, respectively in 78 to 85% …

Job Crafting: The Pursuit Of Happiness At Work, Cristina D. Kirkendall

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Traditional job satisfaction theories focus on either environmental causes or stable underlying personality characteristics as determinants of job satisfaction, giving very little attention to the possibility that employees may be able to affect their own job satisfaction levels. Recent research on job crafting, however, has provided a source of optimism for changing job satisfaction levels. Job crafting is the processes by which employees actively shape their job to fit their individual needs and unlike the traditional models, it offers hope to those employees that work in a dissatisfying environment or whose personalities may not predispose them to high job satisfaction. …

Dangerous Feminine Sexuality: Biblical Metaphors And Sexual Violence Against Women, Lisa M. Ewing

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This analysis responds to an ongoing debate between feminist and traditional readings of sexually violent (SV) metaphors in the prophetic texts of Hosea, Jeremiah, and Ezekiel, and the New Testament book of Revelation. Whereas feminist scholars have often argued that such metaphors are built upon the exploitation of women's sexuality, traditionalist scholars have insisted that the metaphors are merely literary devices that should only be read within their historical and literary contexts. Taking a moderate position, this analysis uses the cognitive metaphor theory to explain that the SV metaphors depend on cognitive associations of dangerous feminine sexuality to relate to …

Fundamental Understanding Of Blisk Analytical Response, Joseph A. Beck

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This effort seeks to increase the reduced-order model fidelity for mistuned Integrally Bladed Rotor (IBR) and Dual Flow-path Integrally Bladed Rotor (DFIBR) response prediction by explicitly accounting for blade geometric and material property deviations. These methods are formulated in a component mode synthesis (CMS) framework utilizing secondary modal reductions in a cyclic symmetry format. The resulting reduced-order models (ROMs) capture perturbations to both blade natural frequencies and mode shapes resulting from geometric deviations. Furthermore, the secondary modal reductions and cyclic symmetry format offer significant computational savings over traditional component mode synthesis methods that give a further reduction in model size. …

Emotional Intelligence In Hypercrisis: A Content Analysis Of World Trade Center Leadership Response To The Terrorist Attacks Of September 11, 2001, Megan Lindsay Schwartz

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The purpose of this qualitative content analysis was to examine World Trade Center (WTC) leadership response to the hypercrisis of 9/11. Information on surviving leaders of four companies housed in the WTC on 9/11 was gathered from ten sources including journal articles, newspaper article, magazine articles, a book, and a documentary. The information was analyzed for evidence of emotional intelligence according to Daniel Goleman's five-construct model. Phrases drawn from the sources were coded according to construct. Results indicated empathy to be the most prevalent response, followed by self-regulation, relationship management, self-awareness, and self-motivation. A second round of coding classified the …

Steps In The Development Of A Full Particle-In-Cell, Monte Carlo Simulation Of The Plasma In The Discharge Chamber Of An Ion Engine, Bryan James Penkal

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The design and development of ion engines is a difficult and expensive process. In order to alleviate these costs and speed ion engine development, it is proposed to further develop a particle-in-cell (PIC), Monte-Carlo collision (MCC) model of an ion engine discharge chamber, which has previously been worked on by the Wright State Ion Engine Modeling Group. Performing detailed and accurate simulations of ion engines can lead to millions of dollars in savings in development costs.

In order to recognize these savings more work must be done on the present day models used to simulate ion engine performance. The work …