143 research outputs found

    Norms of Presentational Force

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    This is the author's accepted manuscript, made available with permission of the American Forensic Association.Can style or presentational devices reasonably compel us to believe, agree, act? I submit that they can, and that the normative pragmatic project explains how. After describing a normative pragmatic approach to presentational force, I analyze and evaluate presentational force in Susan B. Anthony's "Is it a Crime for a U. S. Citizen to Vote" as it apparently proceeds from logic, emotion, and style. I conclude with reflections on the compatibility of the normative pragmatic approach with the recently-developed pragma-dialectical treatment of presentational devices

    A Greater Means to the Greater Good: Ethical Guidelines to Meet Social Movement Organization Advocacy Challenges

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    Existing public relations ethics literature often proves inadequate when applied to social movement campaigns, considering the special communication challenges activists face as marginalized moral visionaries in a commercial public sphere. The communications of counter-hegemonic movements is distinct enough from corporate, nonprofit, and governmental organizations to warrant its own ethical guidelines. The unique communication guidelines most relevant to social movement organizations include promoting asymmetrical advocacy to a greater extent than is required for more powerful organizations and building flexibility into the TARES principles to privilege social responsibility over respect for audience values in activist campaigns serving as ideological critique

    Toward a Silver-Alumina Model System for NOx Reduction Catalysis

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    The growth and morphology of Ag deposited on NiAl(110) and on oxidized NiAl(110) have been investigated by a combination of scanning tunneling microscopy (STM) and high-resolution core-level spectroscopy (HRCLS). While the STM measurements reveal complete wetting and a bilayer growth on clean NiAl(110), Ag nanoparticles with a minimum size of 5 nm were obtained on the oxidized NiAl(110). The difference in Ag growth mode on clean and oxidized NiAl(110) is supported by Ag 3d HRCLS. The binding energy for Ag on clean NiAl(110) is the same as for bulk Ag, while the Ag 3d peak for particles on oxidized NiAl(110) shifts toward the bulk binding energy with increasing size. The adsorption properties at 100 K of CO and NO on oxidized NiAl(110) and on Ag particles on oxidized NiAl(110) were also investigated by probing the C 1s and N 1s core levels. In the case of oxidized NiAl(110), neither CO nor NO adsorbs. In the case of Ag particles on oxidized NiAl(110), CO does not adsorb, but a component at 397 eV is observed in the N 1s level after NO exposures. This component is tentatively assigned to silver nitride, suggesting NO dissociation in the presence of Ag particles on oxidized NiAl(110)

    A unified view of ligand-protected gold clusters as superatom complexes

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    Synthesis, characterization, and functionalization of self-assembled, ligand-stabilized gold nanoparticles are long-standing issues in the chemistry of nanomaterials. Factors driving the thermodynamic stability of well documented discrete sizes are largely unknown. Herein, we provide a unified view of principles that underlie the stability of particles protected by thiolate (SR) or phosphine and halide (PR3, X) ligands. The picture has emerged from analysis of large-scale density functional theory calculations of structurally characterized compounds, namely Au102(SR)44, Au39(PR3)14X6−, Au11(PR3)7X3, and Au13(PR3)10X23+, where X is either a halogen or a thiolate. Attributable to a compact, symmetric core and complete steric protection, each compound has a filled spherical electronic shell and a major energy gap to unoccupied states. Consequently, the exceptional stability is best described by a “noble-gas superatom” analogy. The explanatory power of this concept is shown by its application to many monomeric and oligomeric compounds of precisely known composition and structure, and its predictive power is indicated through suggestions offered for a series of anomalously stable cluster compositions which are still awaiting a precise structure determination

    CO Oxidation on Technological Pd-Al2O3 Catalysts: Oxidation State and Activity

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    The specific CO oxidation activity of palladium versus palladium oxide is still controversially discussed. In this study, 5 wt. % Pd-gamma-Al2O3 catalysts were utilized to investigate the effect of the palladium oxidation state on the CO oxidation activity. Comprehensive in situ and ex situ characterization of different alumina supported PdOx (x = 0-1) phases (by HR-TEM, XRD, and FTIR spectroscopy), combined with kinetic measurements and DFT calculations of CO adsorption, allowed us to assess the catalytic activity of the different PdOx (x = 0-1) species: Supported Pd-0 and substoichiometric PdO

    Interplay between CO Disproportionation and Oxidation: On the Origin of the CO Reaction Onset on Atomic Layer Deposition-Grown Pt/ZrO2Model Catalysts

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    Pt/ZrO2 model catalysts were prepared by atomic layer deposition (ALD) and examined at mbar pressure by operando sum frequency generation (SFG) spectroscopy and near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) combined with differentially pumped mass spectrometry (MS). ALD enables creating model systems ranging from Pt nanoparticles to bulk-like thin films. Polarization-dependent SFG of CO adsorption reveals both the adsorption configuration and the Pt particle morphology. By combining experimental data with ab initio density functional theory (DFT) calculations, we show that the CO reaction onset is determined by a delicate balance between CO disproportionation (Boudouard reaction) and oxidation. CO disproportionation occurs on low-coordinated Pt sites, but only at high CO coverages and when the remaining C atom is stabilized by a favorable coordination. Thus, under the current conditions, initial CO oxidation is found to be strongly influenced by the removal of carbon deposits formed through disproportionation mechanisms rather than being determined by the CO and oxygen inherent activity. Accordingly, at variance with the general expectation, rough Pt nanoparticles are seemingly less active than smoother Pt films. The applied approach enables bridging both the "materials and pressure gaps"

    Surface composition of clean and oxidized Pd75Ag25(100) from photoelectron spectroscopy and density functional theory calculations

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    High resolution photoelectron spectroscopy and density functional theory calculations have been used to study the composition of clean and oxidized Pd75Ag25( 100). The results for the clean surface confirm earlier reports of surface segregation by Wouda et al. (1998), where the top most layers are rich in Ag. The Pd 3d core level component from the surface region is observed at higher binding energies than the contribution from the bulk which is found to be a signature of Pd embedded in Ag. Low energy electron diffraction and scanning tunneling microscopy measurements reveal that oxidation of the Pd75Ag25(100) surface results in a (root 5 x root 5)R27 degrees-O structure similar to the one reported for Pd(100). The calculations suggest that the stable structure is a PdO(101) monolayer supported on a (100) surface rich in Ag at the interface to the stoichiometric alloy. The calculated core level shifts for the oxidized surface are in good agreement with the experimental observations. (C) 2012 Elsevier B.V. All rights reserved
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