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Direct simulation studies of suspended particles and fibre-filled suspensionsJoung, Clint Gwarngsoo January 2003 (has links)
A new Direct Simulation fibre model was developed which allowed flexibility in the fibre during the simulation of fibre suspension flow.This new model was called the �Chain-of-Spheres �model.It was hypothesised that particle shape and deformation could signi ficantly a ffect partic e dynamics,and also suspension bulk properties such as viscosity.Data collected from the simulation showed that flexible fibres in shear flow resulted in an order of 7 −10% bulk relative viscosity increase over the �rigid �fibre result.Results also es- tablished the existence of a relationship between bulk viscosity and particle sti ffness.In comparison with experimental results,other more conventional rigid fibre based methods appeared to underpredict relative viscosity.The flexible fibre method thus markedly improved the ability to estimate relative viscosity.The curved rigid fibre suspension also exhibited increased viscosity of the order twice that of the equivalent straight rigid fibre suspension.With such sensitivity to fibre shape,this result has some important implications for the quality of fibre inclusions used.For consistent viscosity,the shape quality of the fibres was shown to be important. The �Chain of Spheres �simulation was substantially extended to create a new simulation method with the ability to model the dynamics of arbitrarily shaped particles in the Newtonian flow field.This new �3D Particle �simulation method accounted for the inertial force on the particles,and also allowed particles to be embedded in complex flow fields.This method was used to reproduce known dynamics for common particle shapes,and then to predict the unknown dynamics of various other particle shapes in shear flow. In later sections, the simulation demonstrated inertia-induced particle migration inthe non-linear shear gradient Couette cylinder flow,and was used to predict the fibre orientation within a diverging channel flow.The performance of the method was verified against known experimental measurements,observations and theoretical and numerical results where available.The comparisons revealed that the current method reproduced single particle dynamics with great fidelity. The broad aim of this research was to better understand the microstruc- tural dynamics within the fibre-filled suspension and from it,derive useful engineering information on the bulk flow of these fluids.This thesis represents a move forward to meet this broad aim.It is hoped that future researchers may bene fit from the new approaches and algorithms developed here.
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The value of direct and indirect written corrective feedback for intermediate ESL studentsLu, Yang January 2010 (has links)
This study looks at the effectiveness of direct and indirect written corrective feedback (WCF) when using them with 26 intermediate ESL learners’ writings. The study also investigates whether giving the learners the type of feedback they preferred or less preferred would influence their actual performance. WCF, a pedagogy that is often used when helping learners improve their written accuracy, has captured researchers’ attention in recent decades. Truscott (1996) claimed that WCF is ineffective and suggested teachers should abandon it. Therefore, in the early studies, researchers concentrated on examining the effectiveness of WCF, in order to justify the value of using WCF. In recent studies, researchers have proved that WCF is effective in certain contexts, and they have also investigated the value of using different types of WCF, and the value of using it over time. Moreover, in order to help learners to improve in written accuracy, recent studies in the field have also investigated whether WCF is more effective when used on a certain type of linguistic form/structure. With respect to different types of WCF, researchers in recent decades have also paid some attention to learner preference in WCF. However, the relationship between learner preference and the value of using the type of feedback learners prefer has not yet been investigated. In essence, the relationship between learner preference and their actual performance when using the type of feedback they preferred was examined in this study. The study also aimed to look at the effectiveness of WCF over time, and to investigate whether direct feedback or indirect feedback helped learners better. Furthermore, the study also aimed to investigate whether there was a certain type of linguistic form that WCF works best with. A quantitative approach was used in this study in order to show the results more clearly, and to provide statistical evidence on each finding. The study involved questionnaires, and three writing tests: pre-test, immediate post-test, and a delayed post-test. Before the learners did the pre-test, they were asked to complete a questionnaire to select their preferred type of feedback (direct feedback or indirect feedback). Based on their preferences on feedback, they were put into different groups. Group one received direct feedback; group two received indirect feedback; group three received the feedback they preferred (indirect feedback); group four received no linguistic feedback, but general commentaries on their writing were given. The participants (twenty-six students who enrolled in a general English program at AUT University) had completed the questionnaire and the three writing tests. Findings from the study revealed that, most of the learners preferred receiving direct feedback. When examining learner performance between those who received the type of feedback they preferred and those who did not, the former did not outperform than others. However, factors like different levels of scaffolding assistance may have affected the results. Other findings from the study revealed that WCF was effective overtime, especially when using it on errors of present simple tense. The study also found that indirect feedback was more effective than direct feedback. A possible factor that appeared to influence learners’ performance was identified as learners’ motivation in learning. The results of the study contribute to an understanding of the type of feedback that is most suitable for learners at intermediate level, and on which type of linguistic form WCF can work best with. Practical suggestions for pedagogy and further research are also made.
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To be or not to be-- motivated a comparison of students' goal orientation within direct instruction and constructivist schools /Galliger, Courtney C. January 2009 (has links)
Thesis (Ph.D.)--Bowling Green State University, 2009. / Document formatted into pages; contains vi, 68 p. Includes bibliographical references.
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A visual rhetorical analysis of selected Nexium prescription drug advertisements according to the methodology of Sonja FossLaw, Jonathan Henry Ryan. January 2009 (has links)
Thesis (M.A.)--Liberty University, 2009. / Includes bibliographical references.
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A study of Toray's negative working driographic printing plate and the effect ink tack has on toning in the non-image area /Capitano, Larry M. January 1987 (has links)
Thesis (M.S.)--Rochester Institute of Technology, 1987. / Typescript. Includes bibliographical references (leaf 39).
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Traditional ads in an interactive environment /Madansky, Michele. January 1999 (has links)
Thesis (Ph. D.)--University of Chicago Graduate School of Business, June 1999. / Includes bibliographical references. Also available on the Internet.
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Majority rule direct democracy and minority rights /Lewis, Daniel C. January 2008 (has links)
Thesis (Ph.D.)--Michigan State University. Dept. of Political Science, 2008. / Title from PDF t.p. (viewed on July 22, 2009) Includes bibliographical references (p. 165-173). Also issued in print.
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Meaningful choices? understanding and participation in direct democracy in the American states /Reilly, Shauna, January 2009 (has links)
Thesis (Ph. D.)--Georgia State University, 2009. / Title from file title page. Richard N. Engstrom, committee chair; William Downs, Sean Richey, Stephen N. Nicholson, committee members. Description based on contents viewed Aug. 13, 2009. Includes bibliographical references (p. 230-243).
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"When global companies localize" : adaptive strategies of media companies entering India /Pathania, Geetika, January 1998 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 1998. / Vita. Includes bibliographical references (leaves 563-574). Available also in a digital version from Dissertation Abstracts.
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High speed ROM-less direct digital frequency synthesizerYu, Xuefeng. Dai, Fa, January 2009 (has links)
Thesis (Ph. D.)--Auburn University, 2009. / Abstract. Vita. Includes bibliographical references (p. 84-86).
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