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A magnetorheological study of single-walled and multi-walled carbon nanotube dispersions in mineral oil and epoxy resin.

A magnetorheological study of single-walled and multi-walled carbon nanotube dispersions in mineral oil and epoxy resin.

Date: May 2005
Creator: Yang, Zhengtao
Description: Single wall carbon nanotubes (SWNTs) and multi-walled carbon nanotubes (MWNTs) were dispersed in mineral oil and epoxy resin. The magnetorheological properties of these dispersions were studied using a parallel plate rheometer. Strain sweeps, frequency sweeps, magneto sweeps and steady shear tests were conducted in various magnetic fields. G', G", h* and ty increased with increasing magnetic field, which was partially attributed to the increasing degree of the alignment of nanotubes in a stronger magnetic field. The SWNT/mo dispersions exhibited more pronounced magnetic field dependence than SWNT/ep and MWNT/mo counterparts due to their much lower viscosity. The alignment of SWNTs in mineral oil increased with rising nanotube concentration up to 2.5vol% but were significantly restricted at 6.41vol% due to nanotube flocculation.
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Magnetotransport Properties of  AlxIn1-xAsySb1-y/GaSb and Optical Properties of GaAs1-xSbx

Magnetotransport Properties of AlxIn1-xAsySb1-y/GaSb and Optical Properties of GaAs1-xSbx

Date: May 2003
Creator: Lukic- Zrnic, Reiko
Description: Multilayer structures of AlxIn1-xAsySb1-y/GaSb (0.37 £ x £ 0.43, 0.50 £ y £ 0.52), grown by molecular beam epitaxy on GaSb (100) substrates were characterized using variable temperature Hall and Shubnikov-de Haas techniques. For nominally undoped structures both p and n-type conductivity was observed. The mobilities obtained were lower than those predicted by an interpolation method using the binary alloys; therefore, a detailed analysis of mobility versus temperature data was performed to extract the appropriate scattering mechanisms. For p-type samples, the dominant mechanism was ionized impurity scattering at low temperatures and polar optical phonon scattering at higher temperatures. For n-type samples, ionized impurity scattering was predominant at low temperatures, and electron-hole scattering dominated for both the intermediate and high temperature range. Analyses of the Shubnikov-de Haas data indicate the presence of 2-D carrier confinement consistent with energy subbands in GaAszSb1-z potential wells. Epilayers of GaAs1-xSbx (0.19<x<0.71), grown by MBE on semi-insulating GaAs with various substrate orientations, were studied by absorption measurements over the temperature range of 4-300 K. The various substrate orientations were chosen to induce different degrees of spontaneous atomic ordering. The temperature dependence of the energy gap (Eg) for each of these samples was modeled using three semi-empirical ...
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Mail Order Music: the Hinners Organ Company in the Dakotas, 1879-1936

Mail Order Music: the Hinners Organ Company in the Dakotas, 1879-1936

Date: August 1997
Creator: Alcorn-Oppedahl, Allison A. (Allison Ann)
Description: Founded in 1879 by John L. Hinners, the Hinners Organ Company developed a number of stock models of small mechanical-action instruments that were advertised throughout the Midwest. Operating without outside salesmen, the company was one of the first to conduct all of its affairs by mail, including the financial arrangements, selection of the basic design, and custom alterations where required. Buyers first met a company representative when he arrived by train to set up the crated instrument that had been shipped ahead of him. Tracker organs with hand-operated bellows were easily repaired by local craftsmen, and were suited to an area that, for the most part, lacked electricity. In all, the company constructed nearly three thousand pipe organs during its sixty years of operation. Rapid decline of the firm began in the decade prior to 1936 during which the company sold fewer than one hundred instruments, and closed in that year when John's son Arthur found himself without sufficient financial resources to weather the lengthy depression. The studies of the original-condition Hinners organs in the Dakotas include extensive photographs and measurements, and provide an excellent cross section of the smaller instruments produced by the company. They are loud, excellently crafted, ...
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Mainstream Success Following Placement in a Modified Type II Setting

Mainstream Success Following Placement in a Modified Type II Setting

Date: May 2005
Creator: Reeder, Richard C.
Description: The topic of alternative schools is widely available in the literature; however, once a student has been labeled a "troublemaker" and has been placed in a District Alternative Education Program (DAEP), a Type II setting, there is limited information about the overall success of students upon their return to the mainstream. This study compared the success of students formerly placed in a modified disciplinary Type II setting, once they have returned to the mainstream, with their success prior to disciplinary placement. The purpose of the study was to examine if disciplinary measures that remove students from the mainstream environment negatively impact the variables that measure school success, despite legislative mandates such as No Child Left Behind, which advocates success for every student. The population for this study was 86 7th- through 11th-grade students assigned to a DAEP in Texas during the spring of 2003. A comparison of pre- and post-placement dependent variables measuring school success-attendance, passing core courses, behavioral achievement, standardized test score achievement, recidivism, and dropout rates-comprised this study. The independent variables-gender, ethnicity, grade level, socioeconomic status, and disciplinary offense-were used to compare and analyze each dependent variable. The dependent variables of attendance, passing core courses, and behavior demonstrated ...
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Maintaining behavior in a child with autism using a previously neutral stimulus, a remote control tactile stimulus, as the consequence

Maintaining behavior in a child with autism using a previously neutral stimulus, a remote control tactile stimulus, as the consequence

Access: Use of this item is restricted to the UNT Community.
Date: August 2000
Creator: Wheat, Leigh Ann Stiles
Description: Few studies have investigated methods for establishing neutral stimuli as conditioned reinforcers in human subjects. Conditioned reinforcers, however, can alleviate some of the problems encountered in applied behavior analytic (ABA) therapy for children with autism, such as satiation and suitability of reinforcers for specific environments. A series of reversals evaluated the effects of a conditioning procedure involving pairing a neutral stimulus, the remote control stimulus (RCT), with an identified reinforcer. Phase 1 demonstrated that the RCT was neutral. In Phase 2, alternating pairing and testing conditions were run. During testing the effects of pairing were evaluated by the effectiveness of the RCT in maintaining a response in the absence of a previously available reinforcer (extinction test) and in increasing a new response over a baseline level (learning test). Results from the extinction test suggest that under some pairing conditions the RCT can acquire properties of a reinforcer.
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Major Problems of Thailand Economic Development

Major Problems of Thailand Economic Development

Date: May 1969
Creator: Nimmolrat, Aneck
Description: This study is an attempt to examine the major problems of economic development in Thailand. It attempts to analyze the important role of both non-economic and economic factors in the development of the country.
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Makeshift Information Constructions: Information Flow and Undercover Police

Makeshift Information Constructions: Information Flow and Undercover Police

Date: August 2005
Creator: Aksakal, Baris
Description: This dissertation presents the social virtual interface (SVI) model, which was born out of a need to develop a viable model of the complex interactions, information flow and information seeking behaviors among undercover officers. The SVI model was created from a combination of various philosophies and models in the literature of information seeking, communication and philosophy. The questions this research paper answers are as follows: 1. Can we make use of models and concepts familiar to or drawn from Information Science to construct a model of undercover police work that effectively represents the large number of entities and relationships? and 2. Will undercover police officers recognize this model as realistic? This study used a descriptive qualitative research method to examine the research questions. An online survey and hard copy survey were distributed to police officers who had worked in an undercover capacity. In addition groups of officers were interviewed about their opinion of the SVI model. The data gathered was analyzed and the model was validated by the results of the survey and interviews.
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Making a Good Soldier: a Historical and Quantitative Study of the 15th Texas Infantry, C. S. A.

Making a Good Soldier: a Historical and Quantitative Study of the 15th Texas Infantry, C. S. A.

Date: December 1998
Creator: Hamaker, Blake Richard
Description: In late 1861, the Confederate Texas government commissioned Joseph W. Speight to raise an infantry battalion. Speight's Battalion became the Fifteenth Texas Infantry in April 1862, and saw almost no action for the next year as it marched throughout Texas, Arkansas, and the Indian Territory. In May 1863 the regiment was ordered to Louisiana and for the next seven months took an active role against Federal troops in the bayou country. From March to May 1864 the unit helped turn away the Union Red River Campaign. The regiment remained in the trans-Mississippi region until it disbanded in May 1865. The final chapter quantifies age, family status, wealthholdings, and casualties among the regiment's members.
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Making Health Services Functional for Education in Elementary Schools of Cities with Population of Fifteen Thousand

Making Health Services Functional for Education in Elementary Schools of Cities with Population of Fifteen Thousand

Date: 1946
Creator: Binkley, Imogene Van Zandt
Description: The purpose of this thesis is to indicate the scope of the health services that an elementary school needs and to show how these services might be made most fruitful in terms of tangible results.
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The Making of a General :  William Tecumseh Sherman and the Art of War

The Making of a General : William Tecumseh Sherman and the Art of War

Date: January 1965
Creator: Vetter, Charles E.
Description: This thesis is an attempt to trace this evolution which led Sherman to be designated as the first modern general.
Contributing Partner: UNT Libraries