Some interface phenomena associated with the Johnsen-Rahbek effect

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Managing Stress in 8th Grade: CBT and Relaxation Techniques in Small Group Therapy

Stress and anxiety are rampant in school-aged youth and a majority of stress is being experienced beginning as early as middle school. Although anxiety is prevalent in a school setting, there is little to no intervention in place that decreases stress and anxiety as well as minimizes how much class time students are losing. This is especially important in high academic performing school where is it difficult to implement efficient anxiety-reducing interventions without taking students away from academic time. This paper aims to look at the combination of two different forms of therapy: CBT and Relaxation techniques in a small group of 8th grade students over the course of 5 weeks and the effectiveness in which the intervention decreases stress and anxiety in these students over a short amount of time

European Union/South Africa trade, development and co-operation agreement : decision-making, participation and perceived economic impacts

The European Union-South Africa Trade, Development and Co-operation Agreement (EU/SA TDCA), signed in October 1999, is viewed by some in South Africa as not only one of the most important trade and development agreements entered into by the 'new' South African goverrunent, but also a significant agreement for setting precedents for other bi-lateral trade and development pacts between the EU and African, Caribbean and Pacific group of states. This thesis considers two major issues related to the EU/SA TDCA. First, it describes and evaluates the structures that supported the South African side of the TDCA decision-making process. Second, it discusses the potential economic impact of the agreement on South Africa and part of southern African. Prior to the election of the 'new' South African government in 1994, the majority of South Africa's population was excluded - both in terms of access to decision-making structures and from economic prosperity. By exploring the TDCA, the thesis provides a window through wl-dch to examine contemporary access to decision-making processes in South Africa and the likelihood of the TDCA promoting economic prosperity for sections of southern African society, particularly the 'traditionally excluded'. Interviews with key actors who helped formulate the TDCA provide information that enabled the evaluation of the TDCA decision-making process and highlighted potential economic 'winners' and 'losers'. Interviewing representatives of the South African wine and textile sectors provided an opportunity to examine in more detail the likely impact of the agreement and decision-making processes, associated to the TDCA, within South Africa. The results indicate that an overriding message of this thesis is one of complexity. The description of the structures that underpinned the EU/SA TDCA portrayed complex relationships between decision-making 'actors'. In evaluating the inclusivity of the policy formulation process, there was a lack of consensus over who had been included or excluded. Likewise, the identification of potential economic 'winners' and 'losers' proved to be somewhat problematic.Department of Geographical Sciences, University of Plymouth

A numerical model for multigroup radiation hydrodynamics

We present in this paper a multigroup model for radiation hydrodynamics to account for variations of the gas opacity as a function of frequency. The entropy closure model (M1) is applied to multigroup radiation transfer in a radiation hydrodynamics code. In difference from the previous grey model, we are able to reproduce the crucial effects of frequency-variable gas opacities, a situation omnipresent in physics and astrophysics. We also account for the energy exchange between neighbouring groups which is important in flows with strong velocity divergence. These terms were computed using a finite volume method in the frequency domain. The radiative transfer aspect of the method was first tested separately for global consistency (reversion to grey model) and against a well established kinetic model through Marshak wave tests with frequency dependent opacities. Very good agreement between the multigroup M1 and kinetic models was observed in all tests. The successful coupling of the multigroup radiative transfer to the hydrodynamics was then confirmed through a second series of tests. Finally, the model was linked to a database of opacities for a Xe gas in order to simulate realistic multigroup radiative shocks in Xe. The differences with the previous grey models are discussed.Comment: 27 pages, 11 figures, Accepted for publication in JQSR

A Continuum Description of Rarefied Gas Dynamics (I)--- Derivation From Kinetic Theory

We describe an asymptotic procedure for deriving continuum equations from the kinetic theory of a simple gas. As in the works of Hilbert, of Chapman and of Enskog, we expand in the mean flight time of the constituent particles of the gas, but we do not adopt the Chapman-Enskog device of simplifying the formulae at each order by using results from previous orders. In this way, we are able to derive a new set of fluid dynamical equations from kinetic theory, as we illustrate here for the relaxation model for monatomic gases. We obtain a stress tensor that contains a dynamical pressure term (or bulk viscosity) that is process-dependent and our heat current depends on the gradients of both temperature and density. On account of these features, the equations apply to a greater range of Knudsen number (the ratio of mean free path to macroscopic scale) than do the Navier-Stokes equations, as we see in the accompanying paper. In the limit of vanishing Knudsen number, our equations reduce to the usual Navier-Stokes equations with no bulk viscosity.Comment: 16 page