1,167 research outputs found
Parsons Main Street project: Parsons, Kansas [1986]
No full textParsons Resource Team members: Peggy Livingood, Carole Morgan, Ron Peters and Ric Lauman.
"May, 1986."MAP OF PROJECT AREA -- INTRODUCTION -- ORGANIZATION -- PROMOTIONS -- DESIGN -- ECONOMIC RESTRUCTURING -- APPENDICES
Children's author and poet Carole Boston Weatherford
No full textIncludes descriptive metadata provided by producer in MP3 file: "Arts and Culture - Podcasts - Children's author and poet Carole Boston Weatherford.
Carole Oles, 11th Annual ODU Literary Festival
No full textCarole Oles, a member of the Associated Writing Programs Board of Directors, is the author of three books of poetry: The Loneliness Factor (1979), Quarry (1983) and Night Watches: Inventions on the Life of Maria Mitchell (1985). Among her awards are a National Endowment for the Arts Fellowship in Poetry, a Pushcart Prize, and two Fellowships at the MacDowell Colony. She teaches creative writing at Old Dominion University
Using N-gram Analysis for Forensic Author Identification and Text Relatedness
No full textAM Session
Using N-gram Analysis for Forensic Author Identification and Text Relatedness
Carole Chaski, ALIAS Technology LLC and Institute for Linguistic Evidence, Inc, US
Carole Boston Weatherford Claudia Lewis Award 2024 Acceptance Speech
No full textAuthor Carole Boston Weatherford wins the Claudia Lewis Award 2024 for Kin Rooted in Hope from Bank Street College Children\u27s Book Committee.
The Claudia Lewis Award
The Claudia Lewis Award, given for the first time in 1998, honors the best poetry book of the year. The award commemorates the late Claudia Lewis, distinguished children’s book expert and longtime member of the Bank Street College faculty and Children’s Book Committee. She conveyed her love and understanding of poetry with humor and grace.https://educate.bankstreet.edu/cbc_awards/1018/thumbnail.jp
‘Color of Water’ author, James McBride, reflects on race, politics and his new book
No full textAn interview with prize-winning author James McBride on how he explores race in his new collection of stories, @Five-Carat Soul@
The Sun pays "substantial damages" to Ben Stokes [Author Interview]
No full textAuthor interview with the Daily Mail
It’s not all about u: the role of volume and entropy in weakly bound crystal structures
Get PDFCrystals play a vital role in everyday life, from optical electronics and memory storage, to pharmaceuticals and flavourings. Many crystalline compounds can exist in a variety of interchangeable forms that can have remarkably different properties. To safely and reliably use crystalline compounds, it is vital to understand the relative stabilities of these forms and the conditions under which they can interconvert.
For a crystal form to exist it must represent a minimum in free energy, , and relative phase stability can be rationalised using the Gibbs equation (Δ=Δ+Δ−Δ). Attention is often focused on calculations of relative internal energies (Δ), for example through ab initio and force field methods, and descriptions of the enthalpy of individual bonds dominate descriptions of crystal packing. However, at high pressure the volume term (Δ) becomes increasingly significant with the need to minimise volume driving almost all high-pressure phase transitions. The entropy term (Δ) is often neglected from both high pressure and ambient pressure studies. Justified by a claim that its magnitude is too small to ever cause a re-ranking in polymorph stability, in the absence of strong structure directing interactions, this too can become significant.
Chapters 1 and 2 are the introductory chapters of this thesis. Chapter 1 starts by introducing the concepts of polymorphism and the classification of different types of phase transitions. The chapter then describes the origins of the terms of the Gibbs equation and their varying importance under different conditions. Chapter 2 describes the experimental and computational methods used in this thesis and outlines how different terms of the Gibbs equation were determined.
Chapter 3 aims to address the role of volume at pressure by introduction of the CellVol code, for calculation of occupied and void space in crystal structures. The code partitions crystal structures into occupied and unoccupied space based on van der Waals radii to define the limits of inter and intramolecular contacts around atom centres. High pressure crystallographic and spectroscopic studies often show misleading correlations but by studying the contribution of these volume elements individually we have uncovered a highly sensitive method for detecting subtle phase behaviour at high pressure. This method has been used to characterise phase transitions in polymorphs of L-histidine and to identify a crystallographic signature for a transition in naphthalene which has been debated for over 80 years. It is also shown to reveal premonitory behaviour before a reconstructive phase transition. The method was applied to the high-pressure entries in the Cambridge Structural Database (CSD) to reveal similarities in the way molecular compounds use void space to accommodate increased pressure, which explains their narrow range of bulk moduli.
Chapter 4 describes a high-pressure single crystal study on the herbicide glyphosate (N-(phosomethyl)glycine) to 5.17 GPa using a 4:1 mixture of methanol and ethanol as a pressure-transmitting medium. The CellVol code is used to show that two transitions previously suggested to be substantial first order structural reorganisations on the basis of high pressure Raman spectroscopy are both more subtle second order processes. The crystal structure of glyphosate consists of strongly hydrogen-bonded layers, and the first transition corresponds to the onset of a greater compressibility within these layers. The second is an intramolecular feature, corresponding to deformation of the molecular backbone. The previous Raman study and our own crystallographic data show that glyphosate undergoes a more substantial transition above 5.6 GPa, which destroys the integrity of the single crystal. The nature of this transformation is explored further in Chapter 6.
Chapter 5 considers the role of entropy in stabilising weakly bound crystal structures through studies of the C—H⋯F intermolecular bond. Although C—H⋯F interactions are enthalpically weak, they occur much more commonly in crystal structures than would be predicted by chance. In the case of a series of five fluorobenzene derivatives, heat capacity data show that the entropic contribution to free energy at 150 K is of the order −10 to −15 kJ mol⁻¹, which is similar to the stabilisation afforded by N—H⋯N and O—H⋯O hydrogen bonds in ammonia and water, respectively. The origin of entropy in ordered, crystalline solids lies in access to low energy vibrational modes (phonons) which can be observed in inelastic neutron scattering spectra and simulated by periodic density functional theory (DFT) calculations. DFT calculations on the fluorobenzenes, which reproduce experimental entropies and inelastic neutron scattering data, demonstrate that the lowest energy phonons are dominated by motions of the F atoms. The low energies of these vibrations stem both from the mass of the F atom and the highly deformable nature of C—H⋯F interactions, revealed by relatively flat potential curves calculated using symmetry adapted perturbation theory. These data show that the stabilising influence of C—H⋯F interactions can be explained at least as much by the entropic contribution of their deformability as by the enthalpic contribution of the contact energies.
Chapter 6 describes formation of potentially four new high-pressure polymorphs of glyphosate. Although the integrity of a single crystal of glyphosate is lost on slow compression above 5.6 GPa, rapid compression to 5.9 GPa in a 4:1 mixture of methanol and ethanol and to 7.0 GPa in neon as pressure-transmitting media generates two new single-crystal phases. The
crystal structure of the first of these phases was determined from in-house single crystal diffraction data, that of the second from synchrotron data obtained on the P02.2 beamline at DESY. The phase at 7.0 GPa, named phase-II, has a volume 1.023 Å3 per molecule higher than the phase obtained on rapid compression in methanol-ethanol at 5.9 GPa, named phase III. Formation of phase II from phase III with increasing pressure is therefore thermodynamically forbidden. The volume difference corresponds to an estimated Δ-stabilisation of phase III relative to phase II of 17.3 kJ mol−1 at 7.0 GPa. In an attempt to recover the destructive transition seen previously and to potentially drive its transition to phase II or III, neutron powder diffraction data on glyphosate-d4 was completed at ISIS neutron and muon source. This revealed a far more complex structural landscape and the formation of two further phases, named IV and V, which did not fit the structural parameters of phases I, II or III. So far, the structures of phases IV and V have not been characterised further and it is the aim of future work to attempt to recover structural parameters for these phases, possibly through crystal structure prediction. Free energy calculations involving internal energy, volume and entropy are used to establish the driving forces of the single crystal transitions. Extrapolation of the parameters of phase I to the pressures both phase II and III were observed reveals that both transitions are driven by volume as the only significant stabilising contribution
Contract and Domination: A Collaborative Debate about Social Contract Theory
No full textA Collaborative Debate about Social Contract Theory featuring Carole Pateman, author of "The Sexual Contract" and Charles Mills, author of "The Racial Contract
Lorrie Moore has some instructions on how to read her new book
No full textAn interview with the prize-winning author Lorrie Moore about her new collection of essays, "See What Can Be Done.
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