203 research outputs found

    Characteristics of bound modes in coupled dielectric waveguides containing negative index media

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    We investigate the characteristics of guided wave modes in planar coupled waveguides. In particular, we calculate the dispersion relations for TM modes in which one or both of the guiding layers consists of negative index media (NIM)-where the permittivity and permeability are both negative. We find that the Poynting vector within the NIM waveguide axis can change sign and magnitude, a feature that is reflected in the dispersion curves

    Accomplishments Behind, Barriers Ahead: Doing Sociology Without Borders

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    The mission of Societies Without Borders (SWB), to bring “scholars from different continents closer together by showing their different approaches of the same research materials”, creates a space for scholarship like none other. In this article I assess several approaches to doing a sociology without borders that have emerged from SWB, explore some of the remaining barriers to doing this sociology, and offer some ideas on how we might break down the borders that still impede our lives and sciences

    Transparent photonic band in metallodielectric nanostructures

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    Under certain conditions, a transparent photonic band can be designed into a one-dimensional metallodielectric nanofilm structure. Unlike conventional pass bands in photonic crystals, where the finite thickness of the structure affects the transmission of electromagnetic fields having frequency within the pass band, the properties of the transparent band are almost unaffected by the finite thickness of the structure. In other words, an incident field at a frequency within the transparent band exhibits 100% transmission independent of the number of periods of the structure. The transparent photonic band corresponds to excitation of pure eigenstate modes across the entire Bloch band in structures possessing mirror symmetry. The conditions to create these modes and thereby to lead to a totally transparent band phenomenon are discussed.Comment: To be published in Phys. Rev.

    Video chat exams in an online general education linguistics course

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    Video chat exams are a potential solution in online, general education introductory linguistics courses that seek to promote academic integrity, differentiate instruction, center student language and rhetorical practices, and offer multiple assessment modalities. Instructors who try video chat exams will want to clearly communicate expectations, offer practice exams, take steps to mitigate bias, and be sure this strategy aligns with their student learning outcomes as well as logistical concerns, like class size

    Building Wal-Mart with resistance: community political action against a new Wal-Mart supercenter

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    The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.Title from title screen of research.pdf file viewed on (February 20, 2007)Includes bibliographical references.Thesis (M.A.) University of Missouri-Columbia 2006.Dissertations, Academic -- University of Missouri--Columbia -- Sociology.A discussion of the three dimensions of power as they play out in the development arena sets the stage for understanding a local social movement within a specific political context. Through the use of face to face interviews and in depth analysis of local government documents, newspaper articles, and an online elite discourse I uncover the ways in which political context plays a role in determining the strategies and outcomes of social movements which have formed around land use disputes. Overall, if local politics are not designed to encourage citizen involvement, citizens are generally unable to have a role in the development process. In an increasingly privatized world, I make a call for deep democracy in the development process

    Understanding space in an ordinary city

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    Title from PDF of title page (University of Missouri--Columbia, viewed on December 7, 2010).The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file.Dissertation advisor: Dr. David Brunsma and Dr. Wayne Brekhus.Vita.Ph. D. University of Missouri--Columbia 2010.In this dissertation, I emphasize the ordinary city (Robinson, 2006) as a place for building social justice, a place of possibility, and a place where we can see the tensions and frictions (Tsing, 2004) between the stability of social structure and the fluidity of human action. In this context, the ordinary city emerges as a site of innovation and a point for connecting, synthesizing, simplifying, and grounding concepts of space and participation as I move through the lenses of perceived, conceived, and lived (Lefebvre, 1991) in a discussion of the City of Columbia, Missouri. I work to develop a story of the processes that have led to the City of Columbia as it currently exists and how these and other processes can lead us into the future. Embedding this study of the processes of city creation within both the theoretical and practical paradigms of democratic practice has helped me toward a broader understanding of political participation and more inclusive concepts of cityspace and I have made it one of my goals here to renew or recreate some of the bridges between the work done by academics and the needs of the community.Includes bibliographical reference

    Thermophysical property sensitivity effects in steel solidification

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    The simulation of advanced solidification processes via digital computer techniques has gained widespread acceptance during the last decade or so. Models today can predict transient temperature fields, fluid flow fields, important microstructural parameters, and potential defects in castings. However, the lack of accurate thermophysical property data on important industrial alloys threatens to limit the ability of manufacturers to fully capitalize on the technology's benefits. A study of the sensitivity of one such numerical model of a steel plate casting to imposed variations in the data utilized for the thermal conductivity, specific heat, density, and heat of fusion is described. The sensitivity of the data's variability is characterized by its effects on the net solidification time of various points along the centerline of the plate casting. Recommendations for property measurements are given and the implications of data uncertainty for modelers are discussed

    Diversification in Montana county government revenue systems.

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    Improved Probe for Evaluating Compaction of Mold Sand

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    A nominally stationary tubular probe denoted a telescopic probe has been developed as an improved alternative to a prior movable probe used to evaluate the local degree of compaction of mold sand. The probe is inserted vertically to a desired depth in a sand-filled molding flask and the back pressure at the given rate of flow of air is recorded as a measure of the degree of partial impermeability and, hence, of the degree of compaction of sand in the vicinity of the probe tip
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