677 research outputs found

    Illinois Lo-Cal House

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    The increasing scarcity of fuels makes it imperativeto include more energy conservation features in our housing. This circular describes the design, construction, and predicted performance of a house that uses approximately one-third of the energy needed to heat a house of the same size which is built to meet 1974 insulation standards (United States Department of Housing and Urban Development standards for houses located in areas having a heating season of between 4500 and 8000 degree-days). Because of its low-energy requirements for heating, the house has been called the "Illinois Lo-Cal House." If the Lo-Cal House is compared to the typical house of 1950, the savings are even more dramatic. The two features which account for the exceptional reduction are: 1) Superior insulation 2) Solar orientation Of the reduction, about 80% or more is due to the heavy insulation. The remaining reduction is due to the location of most of the windows in the south wall, where they act as solar collectors

    On the Coexistence in RuSr2GdCu2O8 of Superconductivity and Ferromagnetism

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    We review the reasons that make superconductivity unlikely to arise in a ferromagnet. Then, in light of the report by Tallon and collaborators that RuSr2GdCu2O8 becomes superconducting at approximately 35 K which is well below the Curie temperature of 132 K, we consider whether the objections really apply to this compound. Our considerations are supported by local spin density calculations for this compound, which indeed indicate a ferromagnetic RuO2 layer. The Ru moment resides in t_2g orbitals but is characteristic of itinerant magnetism (and is sensitive to choice of exchange-correlation potential and to the atomic positions). Based on the small exchange splitting that is induced in the Cu-O layers, the system seems capable of supporting singlet superconductivity an FFLO-type order parameter and possibly a pi-phase alternation between layers. If instead the pairing is triplet in the RuO2 layers, it can be distinguished by a spin-polarized supercurrent. Either type of superconductivity seems to imply a spontaneous vortex phase if the magnetization is rotated out of the plane.Comment: 3 revtex pages, 2 embedded figures. In press, Proc. HTS99 Conf., Miami, 199

    Orbital moment of a single Co atom on a Pt(111) surface - a view from correlated band theory

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    The orbital magnetic moment of a Co adatom on a Pt(111) surface is calculated in good agreement with experimental data making use of the LSDA+U method. It is shown that both electron correlation induced orbital polarization and structural relaxation play essential roles in orbital moment formation. The microscopic origins of the orbital moment enhancement are discussed

    Electronic structure and spectral properties of Am, Cm and Bk: Charge density self-consistent LDA+HIA calculations in FP-LAPW basis

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    We provide a straightforward and numerically efficient procedure to perform local density approximation + Hubbard I (LDA+HIA) calculations, including self-consistency over the charge density, within the full potential linearized augmented plane wave (FP-LAPW) method. This implementation is all-electron, includes spin-orbit interaction, and makes no shape approximations for the charge density. The method is applied to calculate selected heavy actinides in the paramagnetic phase. The electronic structure and spectral properties of Am and Cm metals obtained are in agreement with previous dynamical mean-field theory (LDA+DMFT) calculations and with available experimental data. We point out that the charge density self-consistent LDA+HIA calculations predict the ff charge on Bk to exceed the atomic integer f8f^8 value by 0.22.Comment: 8 pages, 1 figur

    Orbital magnetic moment and extrinsic spin Hall effect for iron impurity in gold

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    We report electronic structure calculations of an iron impurity in gold host. The spin, orbital and dipole magnetic moments were investigated using the LDA+UU correlated band theory. We show that the {\em around-mean-field}-LDA+UU reproduces the XMCD experimental data well and does not lead to formation of a large orbital moment on the Fe atom. Furthermore, exact diagonalization of the multi-orbital Anderson impurity model with the full Coulomb interaction matrix and the spin-orbit coupling is performed in order to estimate the spin Hall angle. The obtained value γS0.025\gamma_S \approx 0.025 suggests that there is no giant extrinsic spin Hall effect due to scattering on iron impurities in gold.Comment: 5 pages, 2 figure

    Coulomb Correlations and Magnetic Anisotropy in ordered L10L1_0 CoPt and FePt alloys

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    We present results of the magneto-crystalline anisotropy energy (MAE) calculations for chemically ordered L10L1_0 CoPt and FePt alloys taking into account the effects of strong electronic correlations and spin-orbit coupling. The local spin density + Hubbard U approximation (LSDA+U) is shown to provide a consistent picture of the magnetic ground state properties when intra-atomic Coulomb correlations are included for both 3dd and 5dd elements. Our results demonstrate significant and complex contribution of correlation effects to large MAE of these material.Comment: revised version; 4 pages, 2 figure

    Multiplet effects in the electronic structure of δ\delta-Pu, Am and their compounds

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    We propose a straightforward and efficient procedure to perform dynamical mean-field (DMFT) calculations on the top of the static mean-field LDA+U approximation. Starting from self-consistent LDA+U ground state we included multiplet transitions using the Hubbard-I approximation, which yields a very good agreement with experimental photoelectron spectra of δ\delta-Pu, Am, and their selected compounds.Comment: submitted to Europhysics Letter

    Use Of A Real World Business Panel To Assist In MBA Program Outcomes Assessment And Curriculum Refinement

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    The world of business operates in an extremely dynamic environment. Domestic issues (competition, cultural diversity, regulation/deregulation) global issues (competition, economic, cultural/social, and political), and rapidly changing technologies all require business school curricula that are designed to be flexible and proactive as well as reactive. An ever increasingly important responsibility of schools of business is the assessment of outcomes of their programs. Outcomes may be measured on several dimensions. One such measurement is the assessment of the skills/abilities of its graduates. This work will describe the efforts of a business school to engage the local business community in that undertaking
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