23,977 research outputs found

    Spectral-Domain Computation of Fields Radiated by Sources in Non-Birefringent Anisotropic Media

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    We derive the key expressions to robustly address the eigenfunction expansion-based analysis of electromagnetic (EM) fields produced by current sources within planar non-birefringent anisotropic medium (NBAM) layers. In NBAM, the highly symmetric permeability and permittivity tensors can induce directionally-dependent, but polarization independent, propagation properties supporting "degenerate" characteristic polarizations, i.e. four linearly-independent eigenvectors associated with only two (rather than four) unique, non-defective eigenvalues. We first explain problems that can arise when the source(s) specifically reside within NBAM planar layers when using canonical field expressions. To remedy these problems, we exhibit alternative spectral-domain field expressions, immune to such problems, that form the foundation for a robust eigenfunction expansion-based analysis of time-harmonic EM radiation and scattering within such type of planar-layered media. Numerical results demonstrate the high accuracy and stability achievable using this algorithm.Comment: The official (preliminary) published version of this manuscript, along with copyright information, can be found using the provided DOI. IEEE Antennas Wireless Propag. Lett., 201

    Teaching Students with Special Needs in School-Based, Agricultural Education: A Historical Inquiry

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    The purpose of this historical study was to investigate the inclusion of students with special needs in school-based, agricultural education as reported by The Agricultural Education Magazine and the Journal of Agricultural Education over a time period of six decades. The impact of landmark legislation, such as the Vocational Education Act of 1963, the Elementary and Secondary Education Act of 1965, the Education for All Handicapped Children Act of 1975, and the Individuals with Disabilities Act of 1990, were examined. This legislation motivated and supported agricultural education’s efforts to meet the learning needs of special education students by providing modified lessons and learning environments, inclusive SAEs and FFA activities, and focused teacher preparation. Challenges and concerns regarding the placement of special needs students in school-based, agricultural education are also discussed, as well as opportunities for related research in the future, especially about their participation in the FFA
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