Stresses in the vicinity of an un-reinforced mitre intersection: an experimental and finite element comparison

The experimental investigation reported provides elastic stresses in the vicinity of the unreinforced intersection of a single 90° mitred bend, subjected to an in-plane bending moment. The specimen was extensively strain gauged on the outer surface. A small number of rosettes were also laid on the inside surface close to the welded intersection. The procedures used for the successful installation of the inside surface gauges are discussed. In the experiment, consideration was also given to deflections and rotations. Satisfactory comparisons with adaptive-p thin-shell finite element results were obtained in general and differences are explained in terms of the known experimental variables and finite element approximations. The nature of the stresses at such intersections is discussed and various methods of obtaining fatigue 'hot-spot' stresses are considered

Bringing the past to heel: History, identity and violence in Ian McEwan's Black Dogs

Ian McEwan's 1992 novel Black Dogs employs postmodern understandings of history while also critiquing these same perspectives. In particular, by depicting the efforts of its protagonist, Jeremy, to write a memoir of his parents-in-law, it draws attention to the subjectivity of historical writing. While this quality has led some critics to condemn the novel for its escapism and amorality, the authors of the essay argue that Black Dogs is a statement about the necessity of history rather than its futility. Indeed, they read the text as a dramatization of humanity-s ability to bear rather than escape the often troubling burden of the past and an endorsement of the writing of history despite the awareness that historiography, while serving deep-seated human needs, is always problematic

Spatiotemporal properties of multiscale two-dimensional ows

The extraordinary complexity of turbulence has motivated the study of some of its key features in flows with similar structure but simpler or even trivial dynamics. Recently, a novel class of such flows has been developed in the laboratory by applying multiscale electromagnetic forcing to a thin layer of conducting fluid. In spite of being stationary, planar, and laminar these flows have been shown to resemble turbulent ones in terms of energy spectra and particle dispersion. In this thesis, some extensions of these flows are investigated through simulations of a layer-averaged model carried out using a bespoke semi-Lagrangian spline code. The selected forcings generalise the experimental ones by allowing for various kinds of self-similarity and planetary motion of the multiple scales. The spatiotemporal structure of the forcings is largely reflected on the flows, since they mainly arise from a linear balance between forcing and bottom friction. The exponents of the approximate power laws found in the wavenumber spectra can thus be related to the scaling and geometrical forcing parameters. The Eulerian frequency spectra of the unsteady flows exhibit similar power laws originating from the sweeping of the multiple flow scales by the forcing motions. The disparity between fluid and sweeping velocities makes it possible to justify likewise the observed Lagrangian power laws, but precludes a proper analogy with turbulence. In the steady case, the absolute dispersion of tracer particles presents ballistic and diffusive stages, while relative dispersion shows a superquadratic intermediate stage dominated by separation bursts due to the various scales. In the unsteady case, the absence of trapping by fixed streamlines leads to appreciable enhancement of relative dispersion at low and moderate rotation frequency. However, the periodic reversals of the large scale give rise to subdiffusive absolute dispersion and severely impede relative dispersion at high frequency

Evidence for mass ejection associated with long secondary periods in red giants

Approximately 30% of luminous red giants exhibit a Long Secondary Period (LSP) of variation in their light curves, in addition to a shorter primary period of oscillation. The cause of the LSP has so far defied explanation: leading possibilities are binarity and a nonradial mode of oscillation. Here, large samples of red giants in the Large Magellanic Cloud both with and without LSPs are examined for evidence of an 8 or 24 $\mu$m mid-IR excess caused by circumstellar dust. It is found that stars with LSPs show a significant mid-IR excess compared to stars without LSPs. Furthermore, the near-IR $J$-$K$ color seems unaffected by the presence of the 24 $\mu$m excess. These findings indicate that LSPs cause mass ejection from red giants and that the lost mass and circumstellar dust is most likely in either a clumpy or a disk-like configuration. The underlying cause of the LSP and the mass ejection remains unknown.Comment: 6 pages, accepted for publication in Ap

Belyi-extending maps and the Galois action on dessins d'enfants

We study the absolute Galois group by looking for invariants and orbits of its faithful action on Grothendieck's dessins d'enfants. We define a class of functions called Belyi-extending maps, which we use to construct new Galois invariants of dessins from previously known invariants. Belyi-extending maps are the source of the ``new-type'' relations on the injection of the absolute Galois group into the Grothendieck-Teichmuller group. We make explicit how to get from a general Belyi-extending map to formula for its associated invariant which can be implemented in a computer algebra package. We give an example of a new invariant differing on two dessins which have the same values for the other readily computable invariants.Comment: 13 pages, 7 figures; submitted for publication; revisions are that the paper now deals only with Galois invariants of dessins, and that material is slightly expande

The politics of identity in Visigothic Spain: religion and power in the histories of Isidore of Seville

Previous scholarship has interpreted Bishop Isidore of Seville (d. 636) retrospectively as the architect of the medieval Spanish church, as the father of Spanish identity, and as a key figure in the transmission of Classical and Patristic learning to the Middle Ages. Drawing on recent studies on identity formation in the early medieval period and an upsurge in interest in late antique Spain, this book examines the historical Isidore as a social actor managing a complex web of responsibilities and relationships. A comparative analysis of Isidore's historical works demonstrates that writing about the past was a method for reconciling Visigothic kings, nobles and Spanish bishops in a period of transformation. This results in a fresh portrait of Isidore as motivated, both politically and pastorally, to balance competing interests and ensure the spiritual and material security of the people of Spain

Tackling the Turk : an examination of tactics employed by the New Zealand Mounted Rifles Brigade during the Sinai-Palestine campaign of World War I : a thesis presented in partial fulfilment of the requirements for the degree of Master of Philosophy in Defence and Strategic Studies at Massey University, Palmerston North, New Zealand

This thesis examines the tactics employed by the New Zealand Mounted Rifles (NZMR) Brigade during the Sinai Palestine Campaign of World War I. It seeks to determine how the Boer War shaped mounted rifles tactical doctrine prior to World War I, what tactics were employed during the Sinai Palestine campaign itself, and how the tactics evolved over the course of the campaign. It begins by tracing the New Zealand experience in the Boer War, the ensuing development of mounted rifles tactical doctrine and the formation of yeomanry and mounted rifles units immediately prior to World War I. The thesis follows the campaign in Sinai and Palestine, focusing primarily on patrolling operations and attacks, from the re-building of the NZMR Brigade after its return to Egypt from Gallipoli in December 1915, until the conclusion of operations at Amman in September 1918. The thesis finds that by 1914, New Zealand mounted rifles units trained to employ fire tactics, to move mounted, but to conduct attacks dismounted. New Zealanders undertook extensive mounted patrolling from the outset of the campaign. Most attacks were conducted as 'quick' attacks, despite Turkish defensive positions often being well prepared and stubbornly defended. Most attacks employed envelopment of enemy flanks and followed a general pattern of firing lines of dismounted troopers closing on the enemy under the combined weight of their own and neighbouring rifle fire, machine gun fire and artillery support. Attacks usually concluded with a bayonet charge from short range, once firing lines had got close enough to the enemy. Mounted charges were rarely undertaken, despite the spectacular success of the Australian mounted charge at Beersheba. Indeed, the New Zealand commander, General Chaytor, made a deliberate decision to continue employing dismounted tactics. The thesis finds that longevity in command appointments and the influence and experience of Boer War veterans had a positive effect on the tactics used by the NZMR Brigade