5,934 research outputs found
Strategic management: formulation, implementation, and control
No full textPearce and Robinson are celebrated for their practical treatment of complex concepts
Quantitative separation of molybdenum and rhenium from geological materials for isotopic analysis by MC-ICP-MS
No full textWe have developed a new chemical procedure for the quantitative separation of molybdenum (Mo) and rhenium (Re) from a wide variety of geological samples. A single pass anion exchange separation provided complete recovery of pure Mo and Re in a form that was ideal for subsequent isotope and abundance determination by multi-collector inductively coupled plasma-mass spectroscopy (MC-ICP-MS). An enriched 100Mo-97Mo solution, mixed with the sample before digestion, enabled natural mass-dependant isotopic fractionation of Mo to be determined with an external reproducibility of < 0.12‰ (?98Mo/95Mo, 2s). Determination of the concentration of Mo and Re in the same sample was achieved by isotope dilution, with instrumental mass-fractionation of Re being corrected by the simultaneous measurement of the 191Ir/193Ir ratio. We have applied the new procedure to a variety of samples, including seawater, basalt and organic-rich mudrock. The procedure is ideally suited to palaeoredox studies requiring the precise determination of the Mo isotope composition and the Re/Mo ratio from the same sampl
Interactively using Semantic Web knowledge: Creating scalable abstractions with FacetOntology
No full textThe amount of knowledge accessible on the Semantic Web is growing, and there is a need for a scalable solution to facilitate exploring that data. Currently approaches to exploring Semantic Web data either focus on exploring resources individually, following links during exploration, and making little use of collated data, or take the approach of collating and aligning multiple sources into one store for one purpose, and hand-crafting a specific browsing interface onto it. We present an approach that provides a scalable browsing interface, which can browse knowledge from the Semantic Web at will. Our approach creates abstractions of knowledge, collated into facets, which are described using FacetOntology. FacetOntology facilitates describing facets from RDF data, suitable for use in creating datasets for faceted browsing
Growth Morphologies and Mechanisms of Non-Equilibrium Solidified MC Carbide
No full textGrowth morphologies and mechanisms of the carbide of group IVB and VB elements (MC carbide), a typical faceted crystal, were studied with an estimated cooling rate from 102 to 105 K/s. Results showed that although the growth morphologies of the MC carbide vary remarkably with solidification cooling rate, the solid/liquid interface is always atomically smooth, and the growth mechanisms are always lateral growth. The growth mechanism transition from lateral to continuous growth mode, which was predicted by the classic crystal growth theory, was not observed for the TiC type MC carbide within the estimated cooling rate range of 102?105 K/s
Ruth Klüger: la creatività per non “smarrirsi strada facendo”
No full textR. Klüger, a jewish viennese, a US citizen and a germanist, is the Author of two autobiographies “weiter leben”and “unterwegs versore”. Written in a style which alternates between essay and poetry, account and recollection, they are the occasion for the Author to establish a dialogue with the women having as a focus the exchange of experiences and reflections over the status of the feminine emancipation
Eutectic MC Carbide Growth Morphologies of a Laser Clad TiC/FeAl Composite Coating
No full textIn this paper, eutectic MC carbide growth morphology and its evolution with laser scanning speed were studied comprehensively of a laser clad MC carbide reinforced FeAl intermetallic matrix composite coating. As the laser scanning speed increased, the growth morphology of eutectic MC carbide was found to be needle-aligned annulation, butterfly-like and well-developed dendrite
Performance analysis of the MC-CDMA system in frequency selective slow Rayleigh fading channels, DS-CDMA or MC-CDMA?
No full textThis report describes the Bit Error Probability (BEP) performance of Multi-Carrier Code Division Multiple Access (MC-CDMA) system using the RAKE-receiver in frequency selective slow Rayleigh fading channels. The analysis has been carried out by a theoretical approach using the characteristic function method for quadratic form of Gaussian random variables and by computer simulation. The BEP performance of Direct Sequence Code Division Multiple Access (DS-CDMA) system under the same conditions is analysed and compared with the BEP performance of the MC-CDMA system.Electrical Engineering, Mathematics and Computer ScienceTelecommunicatie- en Verkeersbegeleidingssysteme
Seawater redox variations during the deposition of the Kimmeridge Clay Formation, United Kingdom (Upper Jurassic): evidence from molybdenum isotopes and trace metal ratios
Get PDFThe Kimmeridge Clay Formation (KCF) and its equivalents worldwide represent one of the most prolonged periods of organic carbon accumulation of the Mesozoic. In this study, we use the molybdenum (Mo) stable isotope system in conjunction with a range of trace metal paleoredox proxies to assess how seawater redox varied both locally and globally during the deposition of the KCF. Facies with lower organic carbon contents (TOC 1–7 wt %) were deposited under mildly reducing (suboxic) conditions, while organic-rich facies (TOC >7 wt %) accumulated under more strongly reducing (anoxic or euxinic) local conditions. Trace metal abundances are closely linked to TOC content, suggesting that the intensity of reducing conditions varied repeatedly during the deposition of the KCF and may have been related to orbitally controlled climate changes. Long-term variations in ?98/95Mo are associated with the formation of organic-rich intervals and are related to third-order fluctuations in relative sea level. Differences in the mean ?98/95Mo composition of the organic-rich intervals suggest that the global distribution of reducing conditions was more extensive during the deposition of the Pectinatites wheatleyensis and lower Pectinatites hudlestoni zones than during the deposition of the upper Pectinatites hudlestoni and Pectinatites pectinatus zones. The global extent of reducing conditions during the Kimmerigidan was greater than today but was less widespread than during the Toarcian (Early Jurassic) oceanic anoxic event. This study also demonstrates that the Mo isotope system in Jurassic seawater responded to changes in redox conditions in a manner consistent with its behavior in present-day sedimentary environment
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