20,451 research outputs found

    The Raman spectroscopy of ionic liquids : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Chemical Physics at Massey University, New Zealand

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    Raman and infrared spectra were recorded for the ionic liquids [CH3N(C4H8)Bu]+[(F3CSO2)2N]-, [Et3NH]+[(octyl)PO2H]-, [Bu4N]+[(hexyl)PO2H]-, and [Bu4P]+[(octyl)2PO2]- and was compared to spectra calculated by Gaussian 03 using the density functional theory method B3LYP. The experimental and calculated spectra were found to be very similar, indicating that no underlying anomalous effects were perturbing the vibrational modes. The peaks of the experimental and calculated Raman and infrared spectra were found to be broad and intertwined, because of the close proximity of numerous vibrational bands. The differential and absolute scattering cross sections of selected bands of the ionic liquids were determined using a method of comparing the area of the ionic liquid’s peak to standards of known cross section (cyclohexane, carbon tetrachloride, benzene, dichloromethane, and acetonitrile). Differential and absolute cross sections were determined experimentally at wavelengths 416 nm, 487 nm, 514 nm, 532 nm and 633 nm. A-term plots were constructed with these results to obtain the coupling constant and the effective excited state energy. These parameters allowed the calculation of the differential and absolute scattering cross sections at any wavelength. This project is the first in a series of investigations to determine the electron transfer rate of ionic liquids and determine their suitability as materials in new devices

    Linear kinetic Sunyaev-Zel'dovich effect and void models for acceleration

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    There has been considerable recent interest in cosmological models in which the current apparent acceleration is due to a very large local underdensity, or void, instead of some form of dark energy. Here we examine a new proposal to constrain such models using the linear kinetic Sunyaev-Zel'dovich (kSZ) effect due to structure within the void. The simplified "Hubble bubble" models previously studied appeared to predict far more kSZ power than is actually observed, independently of the details of the initial conditions and evolution of perturbations in such models. We show that the constraining power of the kSZ effect is considerably weakened (though still impressive) under a fully relativistic treatment of the problem, and point out several theoretical ambiguities and observational shortcomings which further qualify the results. Nevertheless, we conclude that a very large class of void models is ruled out by the combination of kSZ and other methods.Comment: 15 pages, 9 figures; minor changes, version published in CQG focus section "Inhomogeneous Cosmological Models and Averaging in Cosmology

    Navigating public health chemicals policy in Australia: a policy maker’s and practitioner’s guide

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    Chemicals are ubiquitous in everyday life. Environmental health practitioners rely on a complex web of regulators and policy bodies to ensure the protection of public health, yet few understand the full extent of this web. A lack of understanding can hamper public health response and impede policy development. In this paper we map the public health chemicals policy landscape in Australia and conclude that an understanding of this system is essential for effective environmental health responses and policy development.   NSW Public Health Bulletin 23(12) 217-227 http://dx.doi.org/10.1071/NB1211

    Efficient Computation of Invariant Tori in Volume-Preserving Maps

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    In this paper we implement a numerical algorithm to compute codimension-one tori in three-dimensional, volume-preserving maps. A torus is defined by its conjugacy to rigid rotation, which is in turn given by its Fourier series. The algorithm employs a quasi-Newton scheme to find the Fourier coefficients of a truncation of the series. This technique is based upon the theory developed in the accompanying article by Blass and de la Llave. It is guaranteed to converge assuming the torus exists, the initial estimate is suitably close, and the map satisfies certain nondegeneracy conditions. We demonstrate that the growth of the largest singular value of the derivative of the conjugacy predicts the threshold for the destruction of the torus. We use these singular values to examine the mechanics of the breakup of the tori, making comparisons to Aubry-Mather and anti-integrability theory when possible

    How does implied volatility differ from model based volatility forecasts?

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    Redistribution, work incentives and thirty years of UK tax and benefit reform

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    Governments wishing to reduce inequality by redistributing money from the rich to the poor face the dilemma that in doing so (by increasing tax rates and means-tested benefits, for example) they reduce the incentive for individuals to increase their incomes. Policy-makers have tried to balance these objectives in different ways and, partly as a result of this, the tax and benefit system today is very different from the one that existed thirty years ago. In this paper we look at how the tax and benefit system redistributed income and affected incentives to work in 2009-10, and at the effect of tax and benefit reforms between 1978-79 and 2009-10 on the level of inequality and work incentives.tax, benefits, work incentives
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