2,457 research outputs found

    The \u3csup\u3e13\u3c/sup\u3eC-NMR Solid State Spectroscopy of Various Classes of Coals

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    The 13C-NMR spectra of various classes of coal obtained in the solid state show two resonances, one of which is assigned to aromatic carbon and the other to aliphatic carbon. The resonances are very broad with the high field resonance centered at about 7 ppm below tetramethylsilane and a low field resonance centered at about 140 ppm below tetramethysilane. Based on our previous solid state 13C-NMR studies of graphite and diamond, the high field resonance is typical of a sp3 carbon whereas the low fields resonance is assigned to a sp2 carbon whereas the low fields resonance is assigned to a sp2 carbon. It is found that the antracitic coals have more aromatic (sp2) carbons than the bituminous, subbituminous and lignite coals. The analytical implications of this technique are briefly discussed

    The Solid State \u3csup\u3e13\u3c/sup\u3eC-NMR Spectra of Some Carbides

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    The utility of NMR spectroscopy to the study of liquids or solids dissolved in liquids is well known. This technique has been used infrequently to studies in the solid state[I,2]. Work has been done on diamond, graphite and coa113-6]. The 13C-NMR of ebony and ivory have been studied by the magic angle technique[7]. The solid state 13C-NMR spectra of graphite and diamond can be interpreted in terms of tetrahedral (sp3) and trigonal planar (sp2) carbon atoms[8]. We now report our investigations using solid state 13C-NMR spectroscopy to study various types of carbides

    Impacts of Protected Areas on Local Livelihoods in Cambodia

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    SummaryImpact evaluation methods (mixed effects models and matching) were used to investigate the effect of protected areas (PAs) on poverty and livelihoods in Cambodia, comparing households inside PAs with bordering villages and controls. There was no evidence that PAs exacerbated local poverty or reduce agricultural harvests in comparison with controls. Households bordering the PAs were significantly better off due to greater access to markets and services. Non-timber forest product (NTFP) collectors inside PAs were significantly better off than controls and had greater rice harvests, because they had more secure access to land and forest resources. The PAs in Cambodia therefore have some positive impacts on households that use forest and land resources for their livelihoods

    A Solid State \u3csup\u3e13\u3c/sup\u3eC-NMR Study of Diamonds and Graphites

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    The 13C-NMR spectra of gem quality and industrial diamonds show two resonances with the more intense resonance at high field. Two resonances are also shown in 13C-NMR spectra of various graphites; however, the low field resonance is of greater intensity than the high field resonance in the graphites. The resonances are very broad and they are assigned to graphite type (sp2) carbon and diamond type (sp3) carbon

    Exact norm-conserving stochastic time-dependent Hartree-Fock

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    We derive an exact single-body decomposition of the time-dependent Schroedinger equation for N pairwise-interacting fermions. Each fermion obeys a stochastic time-dependent norm-preserving wave equation. As a first test of the method we calculate the low energy spectrum of Helium. An extension of the method to bosons is outlined.Comment: 21 pages, 3 figures, LaTeX fil

    The implementation of PDP within a practice based curriculum

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    This paper will identify the aims of Personal Development Planning (PDP) in a broad national context. It will consider the approach taken by The University of Salford (UoS) in structuring and implementing PDP requirements, and discuss how such policies may be delivered as an integral part of a practice based programme curriculum. There are a number of models for the implementation of PDP currently being delivered within UK Higher Education Institutions, however the broad range of academic study now available creates a dilemma when trying to assess which model proves the ‘best fit’. The interpretation of a broad strategic vision given by University policy makers may not always readily covert into activities and processes that align with a programme’s curriculum. In this paper, methods for the implementation of PDP at programme level will focus on the UoS Product Design programme as a case study. Taking University policy as a starting point, the programme developed a PDP structure that attempts to align itself coherently with a heavily practice based curriculum

    Affordable spectral measurements of translucent materials

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    We present a spectral measurement approach for the bulk optical properties of translucent materials using only low-cost components. We focus on the translucent inks used in full-color 3D printing, and develop a technique with a high spectral resolution, which is important for accurate color reproduction. We enable this by developing a new acquisition technique for the three unknown material parameters, namely, the absorption and scattering coefficients, and its phase function anisotropy factor, that only requires three point measurements with a spectrometer. In essence, our technique is based on us finding a three-dimensional appearance map, computed using Monte Carlo rendering, that allows the conversion between the three observables and the material parameters. Our measurement setup works without laboratory equipment or expensive optical components. We validate our results on a 3D printed color checker with various ink combinations. Our work paves a path for more accurate appearance modeling and fabrication even for low-budget environments or affordable embedding into other devices
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