CFD analysis of one-dimensional infiltration in vadose zone

This study presents a CFD analysis constructed around PHYSICA, an open framework for multi-physics computational continuum mechanics modelling, to investigate the water movement in unsaturated porous media. The modelling environment is based on a cell-centred finite-volume discretisation technique. A number of test cases are performed in order to validate the correct implementation of Richard's equation for compressible and incompressible fluids. The pressure head form of the equation is used together with the constitutive relationships between pressure, volumetric water content and hydraulic conductivity described by Haverkamp and Van Genuchten models. The flow problems presented are associated with infiltration into initially dry soils with homogeneous or layered geologic settings. Comparison of results with the problems selected from literature shows a good agreement and validates the approach and the implementation.

Zone based systems design framework for the realisation of efficient block cipher based message authentication code algorithms

A zone based systems design framework is described and utilised in the implementation of a message authentication code (MAC) algorithm based on symmetric key block ciphers. The resulting block cipher based MAC algorithm may be used to provide assurance of the authenticity and, hence, the integrity of binary data. Using software simulation to benchmark against the de facto cipher block chaining MAC (CBC-MAC) variant used in the TinySec security protocol for wireless sensor networks and the NIST cipher block chaining MAC standard, CMAC; we show that our zone based systems design framework can lead to block cipher based MAC constructs that point to improvements in message processing efficiency, processing throughput and processing latency.

'Marginal gothic': mediating the monstrous in British romanticism

In this paper I look at texts from the Romantic Period which strategically employ elements of the Gothic genre in what I describe as a `marginal` relationship with the Gothic canon. My intention is both to explore the way the boundaries of the genre might be extended, and to cast fresh light on some of the texts discussed, specifically in relation to the ways in which the `monstrous` is perceived and portrayed as villainy. In the first half of the paper, using Burke’s Philosophical Enquiry on the Sublime and the Beautiful as a starting point, I consider Burke’s Reflections on the Revolution in France, Godwin’s Caleb Williams, Radcliffe’s The Italian, and Blake’s The Marriage of Heaven and Hell as all in various ways examples of `marginal Gothic` that present evil doing as monstrous aberrations, also noting the contemporary reception of Beckford’s Vathek, praised in 1786 for its `accuracy and credibility`. In addition, I suggest that Wordsworth’s `Tintern Abbey` and Book VI of The Prelude provide evidence of marginal, but significant, Gothic influence that references Radcliffe’s and Burke’s explorations of a terror of the unknown. In the second half of the paper I focus on Scott’s Guy Mannering, or The Astrologer (1815) as an important example of a `marginal` Gothic novel. Scott’s reference to Vathek at a key point in his plot suggests that he had read Beckford’s novel as entirely `Gothic`. This discussion incorporates a comparison between Mannering’s youthful enthusiasm for astrological divination, and themes to be found in Shelley’s Frankenstein, notably with respect to the nature of Victor Frankenstein’s response to `old` and `new` science and medicine, and to the creation and control of Gothic monstrosity. In these and in other instances, it will be argued that the `marginal Gothic` of Scott’s novel may be read as a precursor to Shelley’s work. [From the Author]

Marginal adaptation and performance of bioactive dental restorative materials in deciduous and young permanent teeth

Objective: The aim of this study was to investigate the adaptation of different types of restorations towards deciduous and young permanent teeth. Materials and Methods: Class V cavities were prepared in deciduous and young permanent teeth and filled with different materials (a conventional glass-ionomer, a resin-modified glass-ionomer, a poly-acid-modified composite resin and a conventional composite resin). Specimens were aged in artificial saliva for 1, 6, 12 and 18 months, then examined by SEM. Results: The composite resin and the polyacid-modified composite had better marginal adaptation than the glass-ionomers,though microcracks developed in the enamel of the tooth. The glass-ionomers showed inferior marginal quality and durability, but no microcracking of the enamel. The margins of the resin-modified glass-ionomer were slightly superior to the conventional glass-ionomer. Conditioning improved the adaptation of the composite resin, but the type of tooth made little or no difference to the performance of the restorative material. All materials were associated with the formation of crystals in the gaps between the filling and the tooth; the quantity and shape of these crystals varied with the material. Conclusions: Resin-based materials are generally better at forming sound, durable margins in deciduous and young permanent teeth than cements, but are associated with microcracks in the enamel. All fluoride-releasing materials give rise to crystalline deposits.