90 research outputs found

    Electromagnetic Modeling and Measurement of Adaptive Metamaterial Structural Elements

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    This document addresses two major obstacles facing metamaterial development: uncertainty in the characterization of electromagnetic field behavior in metamaterial structures and the relatively small operational bandwidth of metamaterial structures. To address the first obstacle, a method of prediction aided measurement is developed and exploited to examine the field interactions within metamaterial devices. The fusion of simulation and measurement techniques enhances the understanding of the physical interactions of fields in the presence of metamaterials. To address the second obstacle, this document characterizes the effectiveness of an adaptive metamaterial design that incorporates a microelectromechanical systems (MEMS) variable capacitor. Applying voltages to the MEMS device changes the resonant frequency of the metamaterial. In this research, various capacitor layouts are examined with computational models and stripline measurements, leading to recommendations for design improvements

    Social Equity and the Genetically Engineered Crops Controversy

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    Crop Production/Industries, Labor and Human Capital, Y80,

    岡山県の集落社会の構造変化

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    Rural communities in Okayama Prefecture, like those throughout Japan and the remainder of the industrialized world, have undergone rapid economic and social changes in the post-war period. Both policy makers and scholars who are interested in social change in rural areas need to develop an understanding of what those changes have been, what they might be leading to and what the impacts of those changes have been on communities and the people who live there, if they are to effectively promote the social health of these communities. This paper is the first in a series of articles which will carry out such an investigation using the hamlet communities of Okayama Prefecture as the primary data base. This first paper, through an analysis of data on these communities collected by the Japanese Ministry of Agriculture, Fisheries and Forestry will present findings which will delineate the main structural changes which these hamlets underwent in the 1960 to 1980 period. Basically, it will be shown that the two most important factors explaining the evolution of the current structure of these communities are their size and their proximity to major urban areas. While the effects of rapid industrialization have led to a decrease in the importance of agriculture throughout all of the hamlets of the prefecture, the new form into which a hamlet has evolved depends in large measure on its physical location within the prefecture, and its size, as measured by the number of houses and area of cultivated land

    PRODUCT CHARACTERISTICS AFFECTING CONSUMERS' FRESH BEEF CUT PURCHASING DECISIONS IN THE UNITED STATES, JAPAN, AND AUSTRALIA

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    The effects of product and economic characteristics on consumers who purchase six cuts of fresh beef (blocks/parts, steak, thinly sliced, diced, chopped, and ground) in urban areas of the United States, Japan, and Australia will be examined in this paper. Certain product characteristics (such as product freshness and display case cleanliness) were important to consumers of beef in all three countries while other product characteristics (such as price considerations for ground beef consumers) were important for consumers of different beef cuts in all three countries. Some product characteristics varied in importance across consumers from different countries and consumers of different beef cuts.Consumer/Household Economics,

    Schelling\u27s Ages of the World: The Beginning of the Beginning

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    This dissertation traces the development of Schelling\u27s philosophy of time as it appears in the Ages of the World, a work which Schelling himself never completed but which he clearly intended as his magnum opus. My project focuses on Schelling\u27s claim that time is the absolute, a claim which grew out of his Naturphilosophie and which later served as the basis for his fruitful interactions with Kierkegaard in Berlin. In the dissertation, I defend the thesis that Schelling\u27s concept of beginnings paves the way for an organic understanding of time which articulates the latter as a living, breathing entity. In short, my work attempts to prove that Schelling does not conceive of time as a horizon of being, or as a category of consciousness, but as the ultimate basis from which living things grow and evolve. As I write in the introduction to my project, time, for him does not simply pass by; instead, it ripens, and bears fruit. Similarly, living things are not merely in time, but time is in them insofar as living things produce time just as much as they are produced by it. Supporting this thesis is my investigation into Schelling\u27s concept of ground [Grund], which regards time as a contradiction-producing a priori. Time begins with the free decision of the subject; however, this free decision is grounded, paradoxically, in the subject\u27s confrontation with its own fate. Ground, then, has the character of irreducible indeterminacy, giving time the character of unprethinkability [Unvordenklichkeit]. In the opening lines of the Ages of the World, Schelling argues that only the past can be known. However, as I demonstrate, Schelling\u27s insights on ground, in addition to fragmentary nature of his essay, prove otherwise. Instead, what we discover in the Ages of the World is the unfolding of the insight that even the origin of history remains obscure to us, and that this obscurity is endemic to all beginnings in time, past, present, and future

    Electrostatically Tunable Meta-Atoms Integrated With In Situ Fabricated MEMS Cantilever Beam Arrays

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    Two concentric split ring resonators (SRRs) or meta-atoms designed to have a resonant frequency of 14 GHz are integrated with microelectromechanical systems cantilever arrays to enable electrostatic tuning of the resonant frequency. The entire structure was fabricated monolithically to improve scalability and minimize losses from externally wire-bonded components. A cantilever array was fabricated in the gap of both the inner and outer SRRs and consisted of five evenly spaced beams with lengths ranging from 300 to 400 μm. The cantilevers pulled in between 15 and 24 V depending on the beam geometry. Each pulled-in beam increased the SRR gap capacitance resulting in an overall 1-GHz shift of the measured meta-atom resonant frequency

    SRRs Embedded with MEMS Cantilevers to Enable Electrostatic Tuning of the Resonant Frequency

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    A microelectromechanical systems (MEMS) cantilever array was monolithically fabricated in the gap region of a split ring resonator (SRR) to enable electrostatic tuning of the resonant frequency. The design consisted of two concentric SRRs each with a set of cantilevers extending across the split region. The cantilever array consisted of five beams that varied in length from 300 to 400 μm, with each beam adding about 2 pF to the capacitance as it actuated. The entire structure was fabricated monolithically to reduce its size and minimize losses from externally wire bonded components. The beams actuate one at a time, longest to shortest with an applied voltage ranging from 30–60 V. The MEMS embedded SRRs displayed dual resonant frequencies at 7.3 and 14.2 GHz or 8.4 and 13.5 GHz depending on the design details. As the beams on the inner SRR actuated the 14.2 GHz resonance displayed tuning, while the cantilevers on the outer SRR tuned the 8.4 GHz resonance. The 14.2 GHz resonant frequency shifts 1.6 GHz to 12.6 GHz as all the cantilevers pulled-in. Only the first two beams on the outer cantilever array pulled-in, tuning the resonant frequency 0.4 GHz from 8.4 to 8.0 GHz

    Evaluation of the Total Design Method in a survey of Japanese dentists

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    BACKGROUND: This study assessed the application of the Total Design Method (TDM) in a mail survey of Japanese dentists. The TDM was chosen because survey response rates in Japan are unacceptably low and the TDM had previously been used in a general population survey. METHODS: Four hundred and seventy eight dentist members of the Okayama Medical and Dental Practitioner's Association were surveyed. The nine-page, 27-item questionnaire covered dentist job satisfaction, physical practice, and dentist and patient characteristics. Respondents to the first mailing or the one-week follow-up postcard were defined as early responders; others who responded were late responders. Responder bias was assessed by examining age, gender and training. RESULTS: The overall response rate was 46.7% (223/478). The response rates by follow-up mailing were, 18% after the first mailing, 35.4% after the follow-up postcard, 42.3% after the second mailing, and 46.7% after the third mailing. Respondents did not differ from non-respondents in age or gender, nor were there differences between early and late responders. CONCLUSION: The application of TDM in this survey of Japanese dentists produced lower rates of response than expected from previous Japanese and US studies

    Transdisciplinary weed research: new leverage on challenging weed problems?

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    Transdisciplinary weed research (TWR) is a promising path to more effective management of challenging weed problems. We define TWR as an integrated process of inquiry and action that addresses complex weed problems in the context of broader efforts to improve economic, environmental and social aspects of ecosystem sustainability. TWR seeks to integrate scholarly and practical knowledge across many stakeholder groups (e.g. scientists, private sector, farmers and extension officers) and levels (e.g. local, regional and landscape). Furthermore, TWR features democratic and iterative processes of decision-making and collective action that aims to align the interests, viewpoints and agendas of a wide range of stakeholders. The fundamental rationale for TWR is that many challenging weed problems (e.g. herbicide resistance or extensive plant invasions in natural areas) are better addressed systemically, as a part of broad-based efforts to advance ecosystem sustainability, rather than as isolated problems. Addressing challenging weed problems systemically can offer important new leverage on such problems, by creating new opportunities to manage their root causes and by improving complementarity between weed management and other activities. While promising, this approach is complicated by the multidimensional, multilevel, diversely defined and unpredictable nature of ecosystem sustainability. In practice, TWR can be undertaken as a cyclic process of (i) initial problem formulation, (ii) ‘broadening’ of the problem formulation and recruitment of stakeholder participants, (iii) deliberation, negotiation and design of an action agenda for systemic change, (iv) implementation action, (v) monitoring and assessment of outcomes and (vi) reformulation of the problem situation and renegotiation of further actions. Notably, ‘purposive’ disciplines (design, humanities and arts) have central, critical and recurrent roles in this process, as do integrative analyses of relevant multidimensional and multilevel factors, via multiple natural and social science disciplines. We exemplify this process in prospect and retrospect. Importantly TWR is not a replacement for current weed research; rather, the intent is to powerfully leverage current efforts

    Managing Wicked Herbicide-Resistance: Lessons from the Field

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    Herbicide resistance is ‘wicked’ in nature; therefore, results of the many educational efforts to encourage diversification of weed control practices in the United States have been mixed. It is clear that we do not sufficiently understand the totality of the grassroots obstacles, concerns, challenges, and specific solutions needed for varied crop production systems. Weed management issues and solutions vary with such variables as management styles, regions, cropping systems, and available or affordable technologies. Therefore, to help the weed science community better understand the needs and ideas of those directly dealing with herbicide resistance, seven half-day regional listening sessions were held across the United States between December 2016 and April 2017 with groups of diverse stakeholders on the issues and potential solutions for herbicide resistance management. The major goals of the sessions were to gain an understanding of stakeholders and their goals and concerns related to herbicide resistance management, to become familiar with regional differences, and to identify decision maker needs to address herbicide resistance. The messages shared by listening-session participants could be summarized by six themes: we need new herbicides; there is no need for more regulation; there is a need for more education, especially for others who were not present; diversity is hard; the agricultural economy makes it difficult to make changes; and we are aware of herbicide resistance but are managing it. The authors concluded that more work is needed to bring a community-wide, interdisciplinary approach to understanding the complexity of managing weeds within the context of the whole farm operation and for communicating the need to address herbicide resistance
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