196,403 research outputs found
The high-pressure behavior of bloedite:a synchrotron single-crystal X-ray diffraction study.
No full textHigh-pressure single-crystal synchrotron X‑ray diffraction was carried out on a single crystal of bloedite [Na2Mg(SO4)24H2O] compressed in a diamond-anvil cell. The volume-pressure data, collected up to 11.2 GPa, were fitted by a second- and a third-order Birch-Murnaghan equation of state (EOS), yielding V0 = 495.6(7) Å3 with K0 = 39.9(6) GPa, and V0 = 496.9(7) Å3, with K0 = 36(1) GPa and K′ = 5.1 (4) GPa-1, respectively. The axial moduli were calculated using a Birch-Murnaghan EOS truncated at the second order, fixing K′ equal to 4, for a and b axes and a third-order Birch-Murnaghan EOS for c axis. The results were a0 = 11.08(1) and K0 = 56(3) GPa, b0 = 8.20(2) and K0 = 43(3) GPa, and c0 = 5.528(5), K0 = 40(2) GPa, K′ = 1.7(3) GPa-1. The values of the compressibility for a, b, and c axes are ba = 0.0060(3) GPa-1, bb = 0.0078(5) GPa-1, bc = 0.0083(4) GPa-1 with an anisotropic ratio of ba:bb:bc = 0.72:0.94:1. The evolution of crystal lattice and geometrical parameters indicates no phase transition up to 11 GPa. Sulfate polyhedra are incompressible, whereas the Mg polyhedral bulk modulus is 95 GPa. The sodium polyhedron is the softest part of the whole structure with a bulk modulus of 41 GPa. Pressure decreases significantly the distortion of Na coordination. Up to 10 GPa, the donor-acceptor oxygen distances decrease significantly and the difference between the two water molecules decreases with an increase in the strengths of hydrogen bonds. At the same time, the bond lengths from Na and Mg to O atoms of the water molecules decrease faster than other bonds to these cations suggesting that there is a coupling between the Na-Ow and Mg-Ow bond strengths and the “hydrogen transfer” to acceptor O atoms
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
The High-Pressure Phase Transition in Jamesonite: A Single-Crystal Synchrotron X-ray Diffraction Study
No full text"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States" By M. Carey.
No full text"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States: containing bried sketches of the moral and political character of those states.
By M. Carey, member of the American philosophical, and of the American Antiquarian Society, and author of The Olive Branch, Cindiciae Hibernicae, essays on banking, on political economy, and on internal improvement.
To which are now added the English editor's comments on the subject; together with Important Advice to Emigrants, and Cautions Against Impositions Practiced in the Outports
High-pressure optical spectroscopy and X-ray diffraction studies on synthetic cobalt aluminum silicate garnet
No full textDispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Dr. Glendon Swarthout
No full textHosted by Roger M. Busfield, MSU Assistant Professor of Speech and Theater, Meet the Author is designed to introduce a general audience to a contemporary author and their work through in-depth interviews. This episode features a conversation between Dr. Glendon Swarthout, prolific author and English professor at MSU, and assistant professors Sam S. Baskett and Theodore B. Strandness
Low-temperature crystal structure evolution of (Na,Ca)(Cr,Mg)Si2O6 C2/c silicate
No full textThe crystal structure of a clinopyroxene with composition (Na0.75Ca0.25)(Cr0.75Mg0.25)Si2O6 was refined
at 100, 150, 200, 250 and 298 K. The work was performed in the context of an investigation on the lowtemperature
behaviour of A+M3+Si2O6 (with A dominant in Na and M = transition elements) pyroxenes
in order to provide new insights concerning the phase transition and anomalies recently found in the
low-temperature behaviour of NaTiSi2O6 and NaGaSi2O6 compounds. The refinements were done in the
C2/c space group (wR2 between 0.048 and 0.068), and no change of symmetry was observed down to
100 K. Highly-anisotropic axial thermal expansion occurs with the scheme ab 5 aa > ac.
The M2, M1 a nd T polyhedraexpa nd with aM2 > aM1 > aT, as generally observed in pyroxenes. A
discontinuity in the M1 polyhedral volume is observed between 200 and 250 K, similar to the one
observed in NaGaSi2O6 between 190 and 235 K.
The atomic displacement parameters are scaled according to the following pattern: UM2 > UO2 > UO3
5 UO1 > UT 5 UM1. Comparison with previous data along the CaMgSi2O-NaCrSi2O6 join suggests
significant positional disorder for the O1 oxygen, due to repulsion of the 2p orbitals of O1 and the nonbonding
3d electrons of Cr
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