Applications of the DFLU flux to systems of conservation laws

The DFLU numerical flux was introduced in order to solve hyperbolic scalar conservation laws with a flux function discontinuous in space. We show how this flux can be used to solve systems of conservation laws. The obtained numerical flux is very close to a Godunov flux. As an example we consider a system modeling polymer flooding in oil reservoir engineering

An interpretative phenomenological analysis (IPA) investigation of positive psychological change (PPC), including post traumatic growth (PTG)

Positive Psychological Change (PPC) following trauma is a developing field for which there is no standard terminology. The plethora of labels, of which Post Traumatic Growth (PTG) is probably the most common descriptor, arguably masks a significant gap in clinical and theoretical understanding of the phenomenon. One specific gap addressed by this study is PPC following psychological trauma stemming from a Road Traffic Accident (RTA) in which the person involved has subsequently received Eye Movement Desensitisation & Reprocessing (EMDR). To investigate this gap in knowledge, an Interpretative Phenomenological Analysis (IPA) approach was used and twelve participants recruited via a snowball sampling method. The participants were then interviewed using a Semi-structured Interview Questionnaire (SSIQ) and the interviews were then transcribed for IPA analysis. Key themes that emerged included Navigational Struggle (NS) to describe Negative Psychological Change (NPC), and Network Growth (NG), to describe PPC. At any one post-RTA/EMDR point there was a preponderance of one over the other, however, NS and NG were inseparable and found to co-exist along an NS-NG continuum. In addition, Figurative Language Use (FLU) had a significant role in both NS and NG yet was independent of both and apparently driving change towards the development of NG. Whilst NS and NG were both post-trauma phenomena, FLU seemed to hallmark expansion of memory networks as part of a general maturation process post-RTA. Furthermore, there was evidence that participants were incorporating their traumatic experiences via FLU into the rebuilding of their assumptive worlds. To account for these findings, an extension to Adaptive Information Processing (AIP) – the theory widely accepted to underpin EMDR - is proposed based upon a hypothesised Plasticity of Meaning (PoM), which is observable through FLU. PoM predicts which, why and how memory networks connect resulting in the adaptive processing predicted by AIP. The study’s findings are re-examined in terms of consequential modifications to the clinical use of EMDR. Extensive suggestions for further research are provided

Braneworld black holes

The braneworld paradigm provides an interesting framework within which to explore the possibility that our Universe lives in a fundamentally higher dimensional space- time. In this thesis we investigate black holes in the Randall-Sundrum braneworld scenario. We begin with an overview of extra-dimensional physics, from the original proposal of Kaluza and Klein up to the modern braneworld picture of extra dimensions. A detailed description of braneworld gravity is given, with particular emphasis on its compatibility with experimental tests of gravity. We then move on to a discussion of static, spherically symmetric braneworld black hole solutions. Assuming an equation of state for the "Weyl term", which encodes the effects of the extra dimension, we are able to classify the general behaviour of these solutions. We then use the strong field limit approach to investigate the gravitational lensing properties of some candidate braneworld black hole solutions. It is found that braneworld black holes could have significantly different observational signatures to the Schwarzschild black hole of standard general relativity. Rotating braneworld black hole solutions are also discussed, and we attempt to generate rotating solutions from known static solutions using the Newman-Janis complexification "trick"

Computational homogenization for multi scale finite element simulation.

This work presents a general formulation of small and large strain multiscale solid constitutive models based on the volume averaging of the microscopic strain (deformation gradient under large strain) and stress fields over a locally attached microstructure Representative Volume Element (RVE). Both elasto-plastic and hyperelastic behaviour are considered in the modelling of the RVE. A multiscale first-order computational homogenization method for modelling nonlinear deformation processes of evolving multi-phase materials is developed based on the Finite Element discretisation of both macro- and micro-structure. The approach consist of suitably imposing the macroscopic strain on the RVE and then computing the macroscopic stress as the volume average of the microscopic stress field obtained by solving numerically the local (initial) boundary value problem. In this context, the effective (homogenized) tangent modulus is obtained as a function of microstructure stiffness matrix which, in turn, depends upon the material properties and geometrical distribution of the micro-constituents in the RVE. The multiscale material presented here is restricted to two-dimensional problems, however we remark that the extension to three dimensions is trivial. The effectiveness of the proposed strategies is is demonstrated by means of numerical examples

Gravitational waves and dynamical processes in hot newborn compact stars.

Lau, Hoi Kwan.Thesis (M.Phil.)--Chinese University of Hong Kong, 2010.Includes bibliographical references (leaves 208-212).Abstracts in English and Chinese.Chapter 1 --- Introduction --- p.1Chapter 1.1 --- Gravitational wave astronomy --- p.1Chapter 1.2 --- Stellar pulsation and gravitational radiation --- p.3Chapter 1.3 --- Outline --- p.5Chapter 2 --- Hydrostatic stellar structure --- p.8Chapter 2.1 --- Structural equation --- p.9Chapter 3 --- Finite temperature equations of state of nuclear matter --- p.13Chapter 3.1 --- Finite temperature ordinary nuclear matter --- p.13Chapter 3.2 --- Strange Quark Matter --- p.15Chapter 3.3 --- Equilibrium and Dynamic EOS --- p.16Chapter 4 --- Stellar pulsation and gravitational radiation --- p.19Chapter 4.1 --- Linearized theory of general relativity --- p.19Chapter 4.2 --- Stellar oscillation --- p.25Chapter 4.3 --- Quasi-normal Mode --- p.28Chapter 4.3.1 --- f mode --- p.29Chapter 4.3.2 --- p mode --- p.29Chapter 4.3.3 --- g mode --- p.30Chapter 4.3.4 --- w mode --- p.31Chapter 5 --- Gravitational wave spectrum of hot compact stars --- p.32Chapter 5.1 --- Numerical results --- p.32Chapter 5.1.1 --- Temperature effect on QNM --- p.32Chapter 5.1.2 --- Temperature effect and QS model --- p.38Chapter 5.1.3 --- QNM shift due to phase transition --- p.41Chapter 5.2 --- Summary and prospective --- p.48Chapter 6 --- Universality of fundamental mode and spacetime mode --- p.50Chapter 6.1 --- Review --- p.50Chapter 6.2 --- Generic proposal of universalities --- p.53Chapter 6.2.1 --- Moment of Inertia --- p.54Chapter 6.2.2 --- Gravitational wave spectrum --- p.57Chapter 6.3 --- Universality on moment of inertia --- p.63Chapter 6.4 --- Origin of universality --- p.70Chapter 6.4.1 --- Tolman VII model --- p.71Chapter 6.4.2 --- Polytropic Model --- p.76Chapter 6.5 --- Application of universality --- p.82Chapter 6.6 --- Summary --- p.89Chapter 7 --- Quark star properties and gravity mode oscillation --- p.92Chapter 7.1 --- Introduction --- p.92Chapter 7.2 --- g mode frequencies of quark stars --- p.94Chapter 7.2.1 --- Temperature profile and p mode frequency --- p.96Chapter 7.2.2 --- Strange quark mass and Yp mode frequency --- p.104Chapter 7.3 --- Summary --- p.108Chapter 8 --- Gravitational radiation excitation by infalling shell --- p.111Chapter 8.1 --- Introduction --- p.111Chapter 8.2 --- Formalism --- p.116Chapter 8.2.1 --- Connection between star and vacuum --- p.117Chapter 8.2.2 --- Matter source --- p.121Chapter 8.2.3 --- Geodesic --- p.124Chapter 8.2.4 --- Source of infalling dust shell --- p.126Chapter 8.2.5 --- Green's function --- p.127Chapter 8.3 --- Gravitational Wave excitation by collapsing shell --- p.130Chapter 8.4 --- Features of radiation --- p.138Chapter 8.4.1 --- Power spectrum --- p.138Chapter 8.4.2 --- Wave function --- p.144Chapter 8.4.3 --- Energy of excitation --- p.147Chapter 8.5 --- Non-adiabatic oscillation --- p.153Chapter 8.5.1 --- Mathematical Background --- p.154Chapter 8.5.2 --- Numerical results --- p.158Chapter 8.6 --- General relativistic simulation --- p.163Chapter 8.6.1 --- Technical briefing --- p.163Chapter 8.6.2 --- Numerical results --- p.166Chapter 8.7 --- Summary --- p.174Chapter 9 --- Conclusion and remarks --- p.178Chapter A --- Unit conversions --- p.183Chapter B --- Series expansion of quark star EOS --- p.185Chapter C --- Accuracy of simplified mode extraction scheme --- p.188Chapter D --- Computation of moment of inertia --- p.193Chapter E --- Comment of exactness of inference scheme --- p.195Chapter E.1 --- Precision of the mass inferred --- p.195Chapter E.2 --- Accuracy of universality combinations --- p.199Chapter F --- Calculation of sound speed --- p.202Chapter G --- Mode extraction of non-adiabatic oscillation --- p.204Bibliography --- p.20