538 research outputs found

    IUPAC-NIST solubility data series. 81. Hydrocarbons with water and seawater - Revised and updated. Part 8. C9 hydrocarbons with water

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    The mutual solubility and related liquid-liquid equilibria of C9 hydrocarbons with water are exhaustively and critically reviewed. Reports of the experimental determination of solubility in 18 chemically distinct binary systems that appeared in the primary literature prior to the end of 2002 are compiled. For 8 systems, sufficient data are available to allow critical evaluation. All data are expressed as mass percent and mole fraction, as well as the originally reported units. In addition to the standard evaluation criteria used throughout the Solubility Date Series, a new method based on the evaluation of the all experimental data for a given homologous series of aliphatic and aromatic hydrocarbons was used

    IUPAC-NIST solubility data series. 81. Hydrocarbons with water and seawater-revised and updated. Part 5. C7 hydrocarbons with water and heavy water

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    The mutual solubility and related liquid-liquid equilibria of C7 hydrocarbons with water and heavy water are exhaustively and critically reviewed. Reports of experimental determination of solubility in 23 chemically distinct binary systems that appeared in the primary literature prior to end of 2002 are compiled. For 9 systems sufficient data are available to allow critical evaluation. All data are expressed as mass percent and mole fraction as well as the originally reported units. In addition to the standard evaluation criteria used throughout the Solubility Data Series, a new method based on the evaluation of the all experimental data for a given homologous series of aliphatic and aromatic hydrocarbons was used

    Quantum entanglement and information processing via excitons in optically-driven quantum dots

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    We show how optically-driven coupled quantum dots can be used to prepare maximally entangled Bell and Greenberger-Horne-Zeilinger states. Manipulation of the strength and duration of the selective light-pulses needed for producing these highly entangled states provides us with crucial elements for the processing of solid-state based quantum information. Theoretical predictions suggest that several hundred single quantum bit rotations and Controlled-Not gates could be performed before decoherence of the excitonic states takes place.Comment: 3 separate PostScript Figures + 7 pages. Typos corrected. Minor changes added. This updated version is to appear in PR

    Elaia, Pergamon's maritime satellite:The rise and fall of an ancient harbour city shaped by shoreline migration

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    Throughout human history, communication and trade have been key to society. Because maritime trade facilitated the rapid transportation of passengers and freight at relatively low cost, harbours became hubs for traffic, trade and exchange. This general statement holds true for the Pergamenian kingdom, which ruled wide parts of today's western Turkey during Hellenistic times. Its harbour, located at the city of Elaia on the eastern Aegean shore, was used extensively for commercial and military purposes. This study reconstructs the coastal evolution in and around the ancient harbour of Elaia and compares the observed environmental modifications with archaeological and historical findings. We use micropalaeontological, sedimentological and geochemical proxies to reconstruct the palaeoenvironmental dynamics and evolution of the ancient harbour. The geoarchaeological results confirm the archaeological and historical evidence for Elaia's primacy during Hellenistic and early Roman times, and the city's gradual decline during the late Roman period. Furthermore, our study demonstrates that Elaia holds a unique position as a harbour city during ancient times in the eastern Aegean region, because it was not greatly influenced by the high sediment supply associated with river deltas. Consequently, no dredging of the harbour basins is documented, creating exceptional geo-bioarchives for palaeoenvironmental reconstructions

    Local optical spectroscopy of semiconductor nanostructures in the linear regime

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    We present a theoretical approach to calculate the local absorption spectrum of excitons confined in a semiconductor nanostructure. Using the density-matrix formalism, we derive a microscopic expression for the nonlocal susceptibility, both in the linear and nonlinear regimes, which includes a three-dimensional description of electronic quantum states and their Coulomb interaction. The knowledge of the nonlocal susceptibility allows us to calculate a properly defined local absorbed power, which depends on the electromagnetic field distribution. We report on explicit calculations of the local linear response of excitons confined in single and coupled T-shaped quantum wires with realistic geometry and composition. We show that significant interference effects in the interacting electron-hole wave function induce new features in the space-resolved optical spectra, particularly in coupled nanostructures. When the spatial extension of the electromagnetic field is comparable to the exciton Bohr radius, Coulomb effects on the local spectra must be taken into account for a correct assignment of the observed features

    Risks of Tailings Dams Failure

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    Risk and Reliability in Geotechnical Engineerin

    Corporate philanthropy through the lens of ethical subjectivity

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    The dynamic organisational processes in businesses dilute the boundaries between the individual, organisational, and societal drivers of corporate philanthropy. This creates a complex framework in which charitable project selection occurs. Using the example of European tour operators, this study investigates the mechanisms through which companies invest in charitable projects in overseas destinations. Inextricably linked to this is the increasing contestation by local communities as to how they are able to engage effectively with tourism in order to realise the benefits tourism development can bring. This research furthers such debates by exploring the processes through which tour operators facilitate community development through charitable giving. Findings show, with no formal frameworks in existence, project selection depends upon emergent strategies that connect the professional with the personal, with trust being positioned as a central driver of these informal processes. Discretionary responsibilities are reworked through business leaders’ commitment to responsible business practises and the ethical subjectivity guiding these processes
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