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 Collection: UNT Theses and Dissertations
Electrodeposition of Nickel and Nickel Alloy Coatings with Layered Silicates for Enhanced Corrosion Resistance and Mechanical Properties

Electrodeposition of Nickel and Nickel Alloy Coatings with Layered Silicates for Enhanced Corrosion Resistance and Mechanical Properties

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Date: August 2014
Creator: Tientong, Jeerapan
Description: The new nickel/layered silicate nanocomposites were electrodeposited from different pHs to study the influence on the metal ions/layered silicate plating solution and on the properties of the deposited films. Nickel/layered silicate nanocomposites were fabricated from citrate bath atacidic pHs (1.6−3.0), from Watts’ type solution (pH ~4-5), and from citrate bath at basic pH (~9). Additionally, the new nickel/molybdenum/layered silicate nanocomposites were electrodeposited from citrate bath at pH 9.5. The silicate, montmorillonite (MMT), was exfoliated by stirring in aqueous solution over 24 hours. The plating solutions were analyzed for zeta potential, particle size, viscosity, and conductivity to investigate the effects of the composition at various pHs. The preferred crystalline orientation and the crystalline size of nickel, nickel/layered silicate, nickel/molybdenum, and nickel/molybdenum/layered silicate films were examined by X-ray diffraction. The microstructure of the coatings and the surface roughness was investigated by scanning electron microscopy and atomic force microscopy. Nickel/molybdenum/layered silicate nanocomposites containing low content of layered silicate (1.0 g/L) had increase 32 % hardness and 22 % Young’s modulus values over the pure nickel/molybdenum alloy films. The potentiodynamic polarization and electrochemical impedance measurements showed that the nickel/molybdenum/layered silicate nanocomposite layers have higher corrosion resistance in 3.5% NaCl compared to the pure alloy ...
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Evidence for Multiple Functions of a Medicago Truncatula Transporter

Evidence for Multiple Functions of a Medicago Truncatula Transporter

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Date: December 2014
Creator: Huang, Ying-Sheng
Description: Legumes play an important role in agriculture as major food sources for humans and as feed for animals. Bioavailable nitrogen is a limiting nutrient for crop growth. Legumes are important because they can form a symbiotic relationship with soil bacteria called rhizobia that results in nitrogen-fixing root nodules. In this symbiosis, rhizobia provide nitrogen to the legumes and the legumes provide carbon sources to the rhizobia. The Medicago truncatula NPF1.7/NIP/LATD gene is essential for root nodule development and also for proper development of root architecture. Work in our lab on the MtNPF1.7/MtNIP/LATD gene has established that it encodes a nitrate transporter and strongly suggests it has another function. Mtnip-1/latd mutants have pleiotropic defects, which are only partially explained by defects in nitrate transport. MtNPF1.7/NIP/LATD is a member of the large and diverse NPF/NRT1(PTR) transporter family. NPF/NRT1(PTR) members have been shown to transport other compounds in addition to nitrate: nitrite, amino acids, di- and tri-peptides, dicarboxylates, auxin, abscisic acid and glucosinolates. In Arabidopsis thaliana, the AtNPF6.3/NRT1.1( CHL1) transporter was shown to transport auxin as well as nitrate. Atchl1 mutants have defects in root architecture, which may be explained by defects in auxin transport and/or nitrate sensing. Considering the pleiotropic phenotypes observed ...
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Bank Capital, Efficient Market Hypothesis, and Bank Borrowing During the Financial Crisis of 2007 and 2008

Bank Capital, Efficient Market Hypothesis, and Bank Borrowing During the Financial Crisis of 2007 and 2008

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Date: December 2014
Creator: Zia, Mujtaba
Description: During the Great Recession of 2007 and 2008, liquidity and credit dried up, threatening the stability of financial institutions, particularly the banking firms. Traditional source of funds from the last resort, the Discount Window of the Federal Reserve System, failed to remedy the liquidity problem. To assuage the liquidity and credit problem, the Federal Reserve System established several emergency lending facilities and provided unprecedented amount of loans to the banking industry. Using a dataset published by Bloomberg LLP in the aftermaths of the financial crisis, which contains daily loan balances from the Fed, I conduct an event study to test whether financial markets are efficient in reflecting all public, anticipated and classified information in security prices. The most important contribution of this dissertation to the finance discipline and literature is the investigation and analysis of the Fed’s unprecedented loans to the banking industry during the Great Recession and the market reaction to it. The second major contribution of this study is the empirical test of strong form efficient market hypothesis, which has not been feasible due to legal data challenges. This dissertation has other contributions to the finance discipline and banking research. First, I develop an algorithm for measuring the ...
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Exploration of Visual, Acoustic, and Physiological Modalities to Complement Linguistic Representations for Sentiment Analysis

Exploration of Visual, Acoustic, and Physiological Modalities to Complement Linguistic Representations for Sentiment Analysis

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Date: December 2014
Creator: Pérez-Rosas, Verónica
Description: This research is concerned with the identification of sentiment in multimodal content. This is of particular interest given the increasing presence of subjective multimodal content on the web and other sources, which contains a rich and vast source of people's opinions, feelings, and experiences. Despite the need for tools that can identify opinions in the presence of diverse modalities, most of current methods for sentiment analysis are designed for textual data only, and few attempts have been made to address this problem. The dissertation investigates techniques for augmenting linguistic representations with acoustic, visual, and physiological features. The potential benefits of using these modalities include linguistic disambiguation, visual grounding, and the integration of information about people's internal states. The main goal of this work is to build computational resources and tools that allow sentiment analysis to be applied to multimodal data. This thesis makes three important contributions. First, it shows that modalities such as audio, video, and physiological data can be successfully used to improve existing linguistic representations for sentiment analysis. We present a method that integrates linguistic features with features extracted from these modalities. Features are derived from verbal statements, audiovisual recordings, thermal recordings, and physiological sensors signals. The resulting ...
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Jacques-antoine-hippolyte, Comte De Guibert: Father of the Grande Armée

Jacques-antoine-hippolyte, Comte De Guibert: Father of the Grande Armée

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Date: August 2014
Creator: Abel, Jonathan
Description: Jacques-Antoine-Hippolyte, comte de Guibert (1743-1790) dedicated his life and career to creating a new doctrine for the French army. Little about this doctrine was revolutionary. Indeed, Guibert openly decried the anarchy of popular participation in government and looked askance at the early days of the Revolution. Rather, Guibert’s doctrine marked the culmination of an evolutionary process that commenced decades before his time and reached fruition in the Réglement of 1791, which remained in force until the 1830s. Not content with military reform, Guibert demanded a political and social constitution to match. His reforms required these changes, demanding a disciplined, service-oriented society and a functional, rational government to assist his reformed military. He delved deeply, like no other contemporary writer, into the linkages between society, politics, and the military throughout his career and his writings. Guibert exerted an overwhelming influence on military thought across Europe for the next fifty years. His military theories provided the foundation for military reform during the twilight of the Old Regime. The Revolution, which adopted most of Guibert’s doctrine in 1791, continued his work. A new army and way of war based on Guibert’s reforms emerged to defeat France’s major enemies. In Napoleon’s hands, Guibert’s army ...
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High-Density Polyethylene/Peanut Shell Biocomposites

High-Density Polyethylene/Peanut Shell Biocomposites

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Date: May 2014
Creator: Londoño Ceballos, Mauricio
Description: A recent trend in the development of renewable and biodegradable materials has led to the development of composites from renewal sources such as natural fibers. This agricultural activity generates a large amount of waste in the form of peanut shells. The motivation for this research is based on the utilization of peanut shells as a viable source for the manufacture of biocomposites. High-density polyethylene (HDPE) is a plastic largely used in the industry due to its durability, high strength to density ratio, and thermal stability. This research focuses in the mechanical and thermal properties of HDPE/peanut shell composites of different qualities and compositions. The samples obtained were subjected to dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), and mechanical tensile strength tests. TO prepare the samples for analysis, the peanut shells were separated into different mesh sizes and then mixed with HDPE at different concentrations. The results showed that samples with fiber size number 10 exhibited superior strength modulus of 1.65 GPa versus results for HDPE alone at 1.32 GPa. The analysis from the previous experiments helped to determine that the fiber size number 10 at 5%wt. ratio in HDPE provides the most optimal mechanical and thermal results. From tensile ...
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"Stealing Dreams" and Other Stories

"Stealing Dreams" and Other Stories

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Date: December 2014
Creator: Matthews, Elise
Description: The critical preface, "Learning to Break the Rules" discusses workshop rules as guidelines, as well as how and why I learned to break them. The creative portion of this thesis is made up of eight short stories: "The Many Incarnations of Blazer Chief," "Anna's Monsters," "The Pecan Tree's Daughter," "When the Seas Emptied," "The Umbrella Thief," "How to Forget," "Fracture," and "Stealing Dreams."
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Elizabeth Bishop in Brasil: an Ongoing Acculturation

Elizabeth Bishop in Brasil: an Ongoing Acculturation

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Date: August 2014
Creator: Neely, Elizabeth
Description: Elizabeth Bishop (1911–1979), one of the foremost modern American poets, lived in Brasil during seventeen-odd years beginning in 1951. During this time she composed the poetry collection Questions of Travel, stand-alone poems, and fragments as well as prose pieces and translations. This study builds on the work of critics such as Brett Millier and Lorrie Goldensohn who have covered Bishop’s poetry during her Brasil years. However, most American critics have lacked expertise in both Brasilian culture and the Portuguese language that influenced Bishop’s poetry. Since 2000, in contrast, Brasilian critic Paulo Henriques Britto has explored issues of translating Bishop’s poetry into Portuguese, while Maria Lúcia Martins and Regina Przybycien have examined Bishop’s Brasil poems from a Brasilian perspective. However, American and Brasilian scholars have yet to recognize Bishop’s journey of acculturation as displayed through her poetry chronologically or the importance of her belated reception by Brasilian literary and popular culture. This study argues that Bishop’s Brasil poetry reveals her gradual transformation from a tourist outsider to a cultural insider through her encounters with Brasilian history, culture, language, and politics. It encompasses Bishop’s published and unpublished Brasil poetry, including drafts from the Elizabeth Bishop Papers at Vassar College. On a secondary ...
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Control and Automation of a Heat Shrink Tubing Process

Control and Automation of a Heat Shrink Tubing Process

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Date: August 2014
Creator: Yousefi Darani, Shahrokh
Description: Heat shrink tubing is used to insulate wire conductors, protect wires, and to create cable entry seals in wire harnessing industries. Performing this sensitive process manually is time consuming, the results are strongly dependent on the operator’s expertise, and the process presents safety concerns. Alternatively, automating the process minimizes the operators’ direct interaction, decreases the production cost over the long term, and improves quantitative and qualitative production indicators dramatically. This thesis introduces the automation of a heat shrink tubing prototype machine that benefits the wire harnessing industry. The prototype consists of an instrumented heat chamber on a linear positioning system, and is fitted with two heat guns. The chamber design allows for the directing of hot air from the heat guns onto the wire harness uniformly through radially-distributed channels. The linear positioning system is designed to move the heat chamber along the wire harness as the proper shrinkage temperature level is reached. Heat exposure time as a major factor in the heat shrink tubing process can be governed by controlling the linear speed of the heat chamber. A control unit manages the actuator position continuously by measuring the chamber’s speed and temperature. A model-based design approach is followed to design ...
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Evaluating the Feasibility of Accelerometers in Hand Gestures Recognition

Evaluating the Feasibility of Accelerometers in Hand Gestures Recognition

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Date: December 2014
Creator: Karlaputi, Sarada.
Description: Gesture recognition plays an important role in human computer Interaction for intelligent computing. Major applications like Gaming, Robotics and Automated Homes uses gesture recognition techniques which diminishes the usage of mechanical devices. The main goal of my thesis is to interpret SWAT team gestures using different types of sensors. Accelerometer and flex sensors were explored extensively to build a prototype for soldiers to communicate in the absence of line of sight. Arm movements were recognized by flex sensors and motion gestures by Accelerometers. Accelerometers are used to measure acceleration in respect to movement of the sensor in 3D. Flex sensors changes its resistance based on the amount of bend in the sensor. SVM is the classification algorithm used for classification of the samples. LIBSVM (Library for Support Vector Machines) is integrated software for support vector classification, regression and distribution estimation which supports multi class classification. Sensors data is connected to the WI micro dig to digitize the signal and to transmit it wirelessly to the computing device. Feature extraction and Signal windowing were the two major factors which contribute for the accuracy of the system. Mean Average value and Standard Deviation are the two features considered for accelerometer sensor data ...
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