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  Partner: UNT Libraries
 Degree Level: Master's
 Collection: UNT Theses and Dissertations
Design of Multi Band Microwave Devices Using Coupled Line Transmission Lines

Design of Multi Band Microwave Devices Using Coupled Line Transmission Lines

Date: May 2015
Creator: Katakam, Sri
Description: Multi band technology helps in getting multiple operating frequencies using a single microwave device. This thesis presents the design of dual and tri band microwave devices using coupled transmission line structures. Chapter 2 presents the design of a novel dual band transmission line structure using coupled lines. In chapter 3, Design of a dual band branch line coupler and a dual band Wilkinson power divider are proposed using the novel dual band transmission line structure presented in the previous chapter. In chapter 4, Design of a tri band transmission line structure by extending the dual band structure is presented. The Conclusion and future work are presented in chapter 5.
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A Multimodal Investigation of Renewal of Human Avoidance, Perceived Threat, and Emotion

A Multimodal Investigation of Renewal of Human Avoidance, Perceived Threat, and Emotion

Date: May 2015
Creator: Ludlum, Madonna L.
Description: Many people who receive exposure-based treatments for anxiety disorders exhibit a return of fear and avoidance which is often referred to as renewal or relapse. Human and nonhuman research on fear conditioning and renewal has been instrumental in helping understand relapse in anxiety disorders. The purpose of this investigation was to examine renewal of human avoidance and assess whether avoidance may aid in sustaining renewal of fear responses. We adopted a multimodal measurement approach consisting of an approach-avoidance task along with ratings of perceived threat and fear and measures of skin-conductance, a widely used physiological measure of fear. A traditional, single-subject research design was used with six healthy adults. All tasks employed a discrete trial procedure. Experimental conditions included Pavlovian fear conditioning in which increased probability of money loss was paired with a “threat” meter in Context A and later followed extinction in Context B. Fear and avoidance increased to higher threat levels in Context A but not Context B. Renewal testing involved presenting the threat meter on a return to Context A to determine if it evoked fear and avoidance (i.e., relapse). As predicted, renewal testing in Context A showed that increased threat was associated with increased avoidance, ratings ...
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Act Like a Punk, Sing Like a Feminist: a Longitudinal Content Analysis of Feminist Themes in Punk Rock Song Lyrics, 1970-2009

Act Like a Punk, Sing Like a Feminist: a Longitudinal Content Analysis of Feminist Themes in Punk Rock Song Lyrics, 1970-2009

Date: May 2015
Creator: Levine, Lauren. E
Description: Punk rock music has long been labeled sexist as copious media-generated accounts and reports of the genre concentrate on male artists, hyper-masculine performances, and lyrics considered to be aggressive, sexist, and misogynist. However, scholars have rarely examined punk rock music longitudinally, focusing heavily on 1980s and 1990s manifestations of the genre. Furthermore, few systematic content analyses of feminist themes in punk rock song lyrics have been conducted. The present research is a longitudinal content analysis of lyrics of 600 punk rock songs released for four decades between 1970 and 2009 to examine the prevalence of and longitudinal shifts in antiestablishment themes, the prevalence of and longitudinal shifts in sexist themes relative to feminist themes, the prevalence of and longitudinal shifts in specific feminist branches, and what factors are related to feminism. Using top-rated albums retrieved from Sputnik Music’s “Best Punk Albums” charts, systematic random sampling was applied to select 50 songs for each combination of three gender types and four decades. Sexism and feminism were then operationalized to construct a coding sheet to examine relevant dimensions. While the present study found no significant patterns of longitudinal increase or decrease in feminist or sexist themes, it revealed that feminist themes were ...
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The Best Medicine

The Best Medicine

Date: May 2015
Creator: Lechler, Ron
Description: The Best Medicine is an animated documentary that explores the true stories behind the live performances of stand-up comedians. The film juxtaposes live stand-up performances with candid interview footage combined with animation and illustration. Three subjects– Michael Burd, Casey Stoddard, and Jacob Kubon– discuss alcoholism, childhood abuse, and sexual anxiety, respectively. Their candid, intimate interviews reveal personal information, creating a new context with which to understand live stand-up comedy performance. This illustrates themes of finding humor in dark or painful circumstances and the cathartic nature writing and performance.
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Spanish Measurement of Adult Attachment: Reliability and Validity of the Experiences in Close Relationships Scale in a Hispanic American Sample

Spanish Measurement of Adult Attachment: Reliability and Validity of the Experiences in Close Relationships Scale in a Hispanic American Sample

Date: May 2015
Creator: Shelton, Andrew J.
Description: Measures of adult attachment developed in English have been translated and validated in multiple Spanish-speaking countries, yet to this date no self-report adult attachment instrument has been systematically examined for validation with Latinos/Hispanic Americans. The present study examined psychometric properties of a Spanish version of a widely used adult attachment scale, the Experiences in Close Relationships Scale (ECRS), with a bilingual college student sample. Following the dual-language split half (DLSH) quantitative method of evaluating semantic equivalence, 209 bilingual, Latinos/Hispanic American college students recruited from a large public university completed a DLSH version of the ECRS (half English, half Spanish). Internal consistency reliability and DLSH reliability were within acceptable limits, although significantly smaller than coefficients of the English ECRS completed by a large Caucasian sample (n = 459); 3- to 8-week test-retest reliability was also adequate. Exploratory factor analysis revealed a two-factor solution with 35 items accounting for 40% of the variance, which was similar to the English ECRS. Convergent validity was supported by findings that showed significant associations of attachment dimensions with social self-efficacy, self-esteem, depressive symptoms, and comfort with self-disclosure, but not interpersonal trust. Evidence for discriminant validity was found in that attachment dimensions were not significantly associated with ...
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Let the Punishment Fit the Crime: an Overview of the Historical Approach to Probation in the State of Texas

Let the Punishment Fit the Crime: an Overview of the Historical Approach to Probation in the State of Texas

Date: May 2015
Creator: Reichstein, Sheldon Philip
Description: Adult probation evolved in the United States as a result of the suspended sentence concept. As a result of a lack of follow through when an individual obtained a suspended sentence, there was no “checks and balances” to monitor whether an individual completed the guidelines set forth. As time progressed, it became apparent a more cohesive and monitored system was needed. Thus, an energetic and motivated individual, John Augustus, started the concept of probation by taking it upon himself to assist in the rehabilitative process of individuals charged with criminal behavior. Subsequent to his death, the concept of probation was embraced by his advocates who lobbied legislatively in order to enact probation laws that would oversee the success of probationers. It wasn’t until the 1950’s that the counties in the state of Texas took it upon themselves to enact their own system of monitoring of probationers. Over time the states have guided their probation concepts from evidence based research. Juvenile probation in the United States didn’t gain a solid foundation until the end of the 19th century with the development of the first juvenile court in Illinois. It took this country time to understand that juveniles were different than adults ...
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Effect of Friction-stir Processing on the Wear Behavior of Titanium (Ti-1al-8v-5fe) and Stainless Steel (A-286) Alloys

Effect of Friction-stir Processing on the Wear Behavior of Titanium (Ti-1al-8v-5fe) and Stainless Steel (A-286) Alloys

Date: May 2015
Creator: Tinubu, Olusegun Olukunle
Description: The effect of friction stir processing (FSP) on the mechanical wear behavior was investigated for Ti-1Al-8V-5Fe (Ti-185) and stainless steel (Incoloy® A-286) alloys. The Ti-185 and A-286 alloys were tested in different processing conditions, including as rolled (AR), AR+FSP, and AR+FSP+aged. A high frequency reciprocating rig was used to simulate fretting-type wear of these alloys at room temperature. The Vickers micro-hardness and wear rates were calculated and compared for each processing condition. It was determined that along with increasing hardness in the stir zones, FSP resulted in improved wear resistance for both alloys. Specifically, wear rates in the stir zones were reduced to lowest values of 1.6 x 10-5 and 5.8 x 10-7 mm3/N·m for the AR+FSP+aged Ti-185 and A-286 alloys, respectively, despite lower hardness for A-286 alloy. Mechanistic studies were conducted to determine the reason behind these improvements in wear resistance and the effect of FSP on the microstructural evolution during wear. For the Ti-185 alloy, x-ray diffraction revealed that there was a phase transformation from β-Ti (AR+FSP) to α-Ti (AR+FSP+aged). This phase decomposition resulted in the harder and stiffer Ti phase responsible for lowering of wear rate in Ti-185. While x-ray diffraction confirmed the A-286 alloy retains its ...
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Classifying Pairwise Object Interactions: A Trajectory Analytics Approach

Classifying Pairwise Object Interactions: A Trajectory Analytics Approach

Date: May 2015
Creator: Janmohammadi, Siamak
Description: We have a huge amount of video data from extensively available surveillance cameras and increasingly growing technology to record the motion of a moving object in the form of trajectory data. With proliferation of location-enabled devices and ongoing growth in smartphone penetration as well as advancements in exploiting image processing techniques, tracking moving objects is more flawlessly achievable. In this work, we explore some domain-independent qualitative and quantitative features in raw trajectory (spatio-temporal) data in videos captured by a fixed single wide-angle view camera sensor in outdoor areas. We study the efficacy of those features in classifying four basic high level actions by employing two supervised learning algorithms and show how each of the features affect the learning algorithms’ overall accuracy as a single factor or confounded with others.
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Application of Cyclic Polarization of Aluminum 3003 Used in All-aluminum Microchannel Heat Exchangers

Application of Cyclic Polarization of Aluminum 3003 Used in All-aluminum Microchannel Heat Exchangers

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Date: May 2015
Creator: Barnes, Javier
Description: All-aluminum microchannel heat exchangers are designed to significantly reduce refrigerant charge requirements, weight, reduced brazed joints, and decreased potential for leakage by increasing reliability. Al 3003 alloy is corrosion resistant and can be formed, welded, and brazed but the issue with all-aluminum heat exchangers is localized corrosion (pitting) in corrosive environments. Currently, there is no universally accepted corrosion test that all coil manufacturers use to characterize their products. Electrochemical testing method of cyclic polarization was employed in this investigation and relevant parameters including electrolyte corrosive agent and its concentration, electrolyte pH, and applied potential scan rate was varied to find an optimal set of parameters. Results of cyclic polarization of Al 3003 in electrolytes containing various concentrations of NaCl were compared with those of the tests in Sea Water Acidified Accelerated Test (SWAAT) electrolyte and it is shown the SWAAT electrolyte (4.2% sea salt acidified to pH of 2.9) is by far stronger (in terms of corrosivity) than typical 3.5% NaCl solution used in most corrosion testing. Corrosion rates (g/m2yr) of Al 3003 measured in this investigation were comparable to those provided by ISO 9223 standard corresponding to C1 through CX categories. Duration of cyclic polarization test is much shorter ...
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Transition Metal Catalyzed Oxidative Cleavage of C-o Bond

Transition Metal Catalyzed Oxidative Cleavage of C-o Bond

Date: May 2015
Creator: Jiaqi, Wang
Description: The focus of this thesis is on C-O bonds activation by transition metal atoms. Lignin is a potential alternative energy resource, but currently is an underused biomass species because of its highly branched structure. To aid in better understanding this species, the oxidative cleavage of the Cβ-O bond in an archetypal arylglycerol β-aryl ether (β–O–4 Linkage) model compound of lignin with late 3d, 4d, and 5d metals was investigated. Methoxyethane was utilized as a model molecule to study the activation of the C-O bond. Binding enthalpies (ΔHb), enthalpy formations (ΔH) and activation enthalpies (ΔH‡) have been studied at 298K to learn the energetic properties in the C-O bond cleavage in methoxyethane. Density functional theory (DFT) has become a common choice for the transition metal containing systems. It is important to select suitable functionals for the target reactions, especially for systems with degeneracies that lead to static correlation effects. A set of 26 density functionals including eight GGA, six meta-GGA, six hybrid-GGA, and six hybrid-meta-GGA were applied in order to investigate the performance of different types of density functionals for transition metal catalyzed C-O bond cleavage. A CR-CCSD(T)/aug-cc-pVTZ was used to calibrate the performance of different density functionals.
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