10 resultados para Center for Materials Science (U.S.). Metallurgy Division.

em Digital Commons at Florida International University


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As the first step toward developing benchmarks for travel counselor training, the authors identify the methods and characteristics of existing travel counselor-training programs in the U.S. Responses from 30 out of 50 state tourism agencies indicate that 12 different methods of training are emplyed; however, usage and satisfaction with these various training methods vary.

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During the Cold War the foreign policy of the American Federation of Labor and Congress of Industrial Organizations (AFL-CIO), was heavily criticized by scholars and activists for following the lead of the U.S. state in its overseas operations. In a wide range of states, the AFL-CIO worked to destabilize governments selected by the U.S. state for regime change, while in others the Federation helped stabilize client regimes of the U.S. state. In 1997 the four regional organizations that previously carried out AFL-CIO foreign policy were consolidated into the American Center for International Labor Solidarity (Solidarity Center). My dissertation is an attempt to analyze whether the foreign policy of the AFL-CIO in the Solidarity Center era is marked by continuity or change with past practices. At the same time, this study will attempt to add to the debate over the role of non-governmental organizations (NGOs) in the post-Cold War era, and its implications for future study. Using the qualitative "process-tracing" detailed by of Alexander George and Andrew Bennett (2005) my study examines a wide array of primary and secondary sources, including documents from the NED and AFL-CIO, in order to analyze the relationship between the Solidarity Center and the U.S. state from 2002-2009. Furthermore, after analyzing broad trends of NED grants to the Solidarity Center, this study examines three dissimilar case studies including Venezuela, Haiti, and Iraq and the Middle East and North African (MENA) region to further explore the connections between U.S. foreign policy goals and the Solidarity Center operations. The study concludes that the evidence indicates continuity with past AFL-CIO foreign policy practices whereby the Solidarity Center follows the lead of the U.S. state. It has been found that the patterns of NED funding indicate that the Solidarity Center closely tailors its operations abroad in areas of importance to the U.S. state, that it is heavily reliant on state funding via the NED for its operations, and that the Solidarity Center works closely with U.S. allies and coalitions in these regions. Finally, this study argues for the relevance of "top-down" NGO creation and direction in the post-Cold War era.

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During the Cold War the foreign policy of the American Federation of Labor and Congress of Industrial Organizations (AFL-CIO), was heavily criticized by scholars and activists for following the lead of the U.S. state in its overseas operations. In a wide range of states, the AFL-CIO worked to destabilize governments selected by the U.S. state for regime change, while in others the Federation helped stabilize client regimes of the U.S. state. In 1997 the four regional organizations that previously carried out AFL-CIO foreign policy were consolidated into the American Center for International Labor Solidarity (Solidarity Center). My dissertation is an attempt to analyze whether the foreign policy of the AFL-CIO in the Solidarity Center era is marked by continuity or change with past practices. At the same time, this study will attempt to add to the debate over the role of non-governmental organizations (NGOs) in the post-Cold War era, and its implications for future study. Using the qualitative “process-tracing” detailed by of Alexander George and Andrew Bennett (2005) my study examines a wide array of primary and secondary sources, including documents from the NED and AFL-CIO, in order to analyze the relationship between the Solidarity Center and the U.S. state from 2002-2009. Furthermore, after analyzing broad trends of NED grants to the Solidarity Center, this study examines three dissimilar case studies including Venezuela, Haiti, and Iraq and the Middle East and North African (MENA) region to further explore the connections between U.S. foreign policy goals and the Solidarity Center operations. The study concludes that the evidence indicates continuity with past AFL-CIO foreign policy practices whereby the Solidarity Center follows the lead of the U.S. state. It has been found that the patterns of NED funding indicate that the Solidarity Center closely tailors its operations abroad in areas of importance to the U.S. state, that it is heavily reliant on state funding via the NED for its operations, and that the Solidarity Center works closely with U.S. allies and coalitions in these regions. Finally, this study argues for the relevance of “top-down” NGO creation and direction in the post-Cold War era.

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As time advances, man has been able to control technology in finer and finer detail. The microelectronics era is an example of this, with control down to the micrometer. Experts agree that we may be entering a new era, controlling technology down to the nanometer. One aspect of such control is making materials in the nanometer range, i.e. nanoparticles. For this purpose, a new magnetron-sputtering gun, inert gas condensation, nanoparticle source has been designed, built, and tested. ^ Films made from cobalt, nickel, tantalum, molybdenum, chromium, and aluminum have been investigated. Transmission Electron Microscope measurements done at the University of Illinois confirm the thin films are nanostructured. This was also confirmed by Atomic Force Microscope measurements made at the F.I.U. Thin Film Laboratory. ^ Composition, optical and magnetic properties have been measured. In most cases, unique properties have been found that differ significantly from bulk properties. Rutherford Backscattering measurements done at the University of Illinois determined significant percentages of oxygen and carbon in the samples, possibly due to interactions with air. Because of this, optical properties are a composite of oxide, metal, and void properties. Magnetic materials were determined to have spin-glass properties below the irreversibility temperature and superparamagnetic properties above it. Indications of possible future uses for these nanostructured materials are discussed. ^

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Nanocrystalline and bulk samples of “Fe”-doped CuO were prepared by coprecipitation and ceramic methods. Structural and compositional analyses were performed using X-ray diffraction, SEM, and EDAX. Traces of secondary phases such as CuFe2O4, Fe3O4, and α-Fe2O3 having peaks very close to that of the host CuO were identified from the Rietveld profile analysis and the SAED pattern of bulk and nanocrystalline Cu0.98Fe0.02O samples. Vibrating Sample Magnetometer (VSM) measurements show hysteresis at 300 K for all the samples. The ferrimagnetic Neel transition temperature () was found to be around 465°C irrespective of the content of “Fe”, which is close to the value of cubic CuFe2O4. High-pressure X-Ray diffraction studies were performed on 2% “Fe”-doped bulk CuO using synchrotron radiation. From the absence of any strong new peaks at high pressure, it is evident that the secondary phases if present could be less than the level of detection. Cu2O, which is diamagnetic by nature, was also doped with 1% of “Fe” and was found to show paramagnetic behavior in contrast to the “Fe” doped CuO. Hence the possibility of intrinsic magnetization of “Fe”-doped CuO apart from the secondary phases is discussed based on the magnetization and charge state of “Fe” and the host into which it is substituted.

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Poor informational reading and writing skills in early grades and the need to provide students more experience with informational text have been identified by research as areas of concern. Wilkinson and Son (2011) support future research in dialogic approaches to investigate the impact dialogic teaching has on comprehension. This study (N = 39) examined the gains in reading comprehension, science achievement, and metacognitive functioning of individual second grade students interacting with instructors using dialogue journals alongside their textbook. The 38 week study consisted of two instructional phases, and three assessment points. After a period of oral metacognitive strategies, one class formed the treatment group (n=17), consisting of two teachers following the co-teaching method, and two classes formed the comparison group ( n=22). The dialogue journal intervention for the treatment group embraced the transactional theory of instruction through the use of dialogic interaction between teachers and students. Students took notes on the assigned lesson after an oral discussion. Teachers responded to students' entries with scaffolding using reading strategies (prior knowledge, skim, slow down, mental integration, and diagrams) modeled after Schraw's (1998) strategy evaluation matrix, to enhance students' comprehension. The comparison group utilized text-based, teacher-led whole group discussion. Data were collected using different measures: (a) Florida Assessments for Instruction in Reading (FAIR) Broad Diagnostic Inventory; (b) Scott Foresman end of chapter tests; (c) Metacomprehension Strategy Index (Schmitt, 1990); and (d) researcher-made metacognitive scaffolding rubric. Statistical analyses were performed using paired sample t-tests, regression analysis of covariance, and two way analysis of covariance. Findings from the study revealed that experimental participants performed significantly better on the linear combination of reading comprehension, science achievement, and metacognitive function, than their comparison group counterparts while controlling for pretest scores. Overall, results from the study established that teacher scaffolding using metacognitive strategies can potentially develop students' reading comprehension, science achievement, and metacognitive awareness. This suggests that early childhood students gain from the integration of reading and writing when using authentic materials (science textbooks) in science classrooms. A replication of this study with more students across more schools, and different grade levels would improve the generalizability of these results.

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Owing to an increased risk of aging population and a higher incidence of coronary artery disease (CAD), there is a need for more reliable and safer treatments. Numerous varieties of durable polymer-coated drug eluting stents (DES) are available in the market in order to mitigate in-stent restenosis. However, there are certain issues regarding their usage such as delayed arterial healing, thrombosis, inflammation, toxic corrosion by-products, mechanical stability and degradation. As a result, significant amount of research has to be devoted to the improvement of biodegradable polymer-coated implant materials in an effort to enhance their bioactive response. ^ In this investigation, magneto-electropolished (MEP) and a novel biodegradable polymer coated ternary Nitinol alloys, NiTiTa and NiTiCr were prepared to study their bio and hemocompatibility properties. The initial interaction of a biomaterial with its surroundings is dependent on its surface characteristics such as, composition, corrosion resistance, work of adhesion and morphology. In-vitro corrosion tests such as potentiodynamic polarization and electrochemical impedance spectroscopic (EIS) studies were conducted to determine the coating stability and longevity. In-vitro hemocompatibility studies and HUVEC cell growth was performed to determine their thrombogenic and biocompatibility properties. Critical delamination load of the polymer coated Nitinol alloys was determined using Nano-scratch analysis. Sulforhodamine B (SRB) assays were performed to elucidate the effect of metal ions leached from Nitinol alloys on the viability of HUVEC cells. Scanning Electron Microscopy (SEM), X-ray Photoelectron Spectroscopy (XPS), contact angle meter and X-ray diffraction (XRD) were used to characterize the surface of the alloys. ^ MEP treated and polymer coated (PC) Nitinol alloys displayed a corrosion resistant polymer coating as compared to uncoated alloys. MEP and PC has resulted in reduced Ni and Cr ion leaching from NiTi5Cr and subsequently low cytotoxicity. Thrombogenicity tests revealed significantly less platelet adhesion and confluent endothelial cell growth on polymer coated and uncoated ternary MEP Nitinol alloys. Finally, this research addresses the bio and hemocompatibility of MEP + PC ternary Nitinol alloys that could be used to manufacture blood contacting devices such as stents and vascular implants which can lead to lower U.S. healthcare spending.^

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The purpose of this study was to evaluate the incidence of corrosion and fretting in 48 retrieved titanium-6aluminum-4vanadium and/or cobalt-chromium-molybdenum modular total hip prosthesis with respect to alloy material microstructure and design parameters. The results revealed vastly different performance results for the wide array of microstructures examined. Severe corrosion/fretting was seen in 100% of as-cast, 24% of low carbon wrought, 9% of high carbon wrought and 5% of solution heat treated cobalt-chrome. Severe corrosion/fretting was observed in 60% of Ti-6Al-4V components. Design features which allow for fluid entry and stagnation, amplification of contact pressure and/or increased micromotion were also shown to play a role. 75% of prosthesis with high femoral head-trunnion offset exhibited poor performance compared to 15% with a low offset. Large femoral heads (>32mm) did not exhibit poor corrosion or fretting. Implantation time was not sufficient to cause poor performance; 54% of prosthesis with greater than 10 years in-vivo demonstrated none or mild corrosion/fretting.