Far O\u27er The Deep Blue Sea

[Verse 1]The moon is beaming brightly love, Upon the deep blue seaA trusty crew is waiting near,For thee, dear girl, for thee!Then leave thy downy couch, my love, And with thy sailor flee;His gallant bark shall bear thee safe,Far o\u27er the deep blue sea,Far o\u27er the deep, the deep blue sea. [Verse 2]The storm-bird sleeps upon the rockNo angry surges roarNo sound disturbs the slumb\u27ring deepNot e\u27en the dipping oar:No watchful eye is on thee now,Then,dearest, hie with me,And share a daring sailor\u27s love,Far o\u27er the deep blue sea. [Verse 3]She comes! she comes! with trembling stepOh! happy shall we beWhen safely moor\u27d, on other shores,From ev\u27ry danger free!Now, speed thee on my trusty bark,Our hopes are all on theeBear, bear, us to our peaceful homeFar o\u27er the deep blue sea

Using multibeam echosounder backscatter to characterize seafloor features

Geocoder Processing Gives Multibeam Echosounder Backscatter an Advantage Over Side Scan Sonar in Producing Reliable Seafloor Map

On the formation of axial corner vortices during spin-up in a cylinder of square cross-section

We present experimental and theoretical results for the adjustment of a fluid (homogeneous or linearly stratified), which is initially rotating as a solid body with angular frequency Ω−ΔΩ, to a nonlinear increase ΔΩ in the angular frequency of all bounding surfaces. The fluid is contained in a cylinder of square cross-section which is aligned centrally along the rotation axis, and we focus on the O(Ro−1Ω−1) time scale, where Ro=ΔΩ/Ω is the Rossby number. The flow development is shown to be dominated by unsteady separation of a viscous sidewall layer, leading to an eruption of vorticity that becomes trapped in the four vertical corners of the container. The longer-time evolution on the standard ‘spin-up’ time scale, E−1/2Ω−1 (where E is the associated Ekman number), has been described in detail for this geometry by Foster & Munro (J. Fluid Mech., vol. 712, 2012, pp. 7–40), but only for small changes in the container’s rotation rate (i.e. Ro≪1). In the linear case, for Ro≪E1/2≪1, there is no sidewall separation. In the present investigation we focus on the fully nonlinear problem, Ro=O(1), for which the sidewall viscous layers are Prandtl boundary layers and (somewhat unusually) periodic around the container’s circumference. Some care is required in the corners of the container, but we show that the sidewall boundary layer breaks down (separates) shortly after an impulsive change in rotation rate. These theoretical boundary-layer results are compared with two-dimensional Navier–Stokes results which capture the eruption of vorticity, and these are in turn compared to laboratory observations and data. The experiments show that when the Burger number, S=(N/Ω)2 (where N is the buoyancy frequency), is relatively large – corresponding to a strongly stratified fluid – the flow remains (horizontally) two-dimensional on the O(Ro−1Ω−1) time scale, and good quantitative predictions can be made by a two-dimensional theory. As S was reduced in the experiments, three-dimensional effects were observed to become important in the core of each corner vortex, on this time scale, but only after the breakdown of the sidewall layers

2008 Survey of Technology Enhanced Learning for higher education in the UK

UCISA, JIS

A Mathematical Model for Flash Sintering

A mathematical model is presented for the Joule heating that occurs in a ceramic powder compact during the process of flash sintering. The ceramic is assumed to have an electrical conductivity that increases with temperature, and this leads to the possibility of runaway heating that could facilitate and explain the rapid sintering seen in experiments. We consider reduced models that are sufficiently simple to enable concrete conclusions to be drawn about the mathematical nature of their solutions. In particular we discuss how different local and non-local reaction terms, which arise from specified experimental conditions of fixed voltage and current, lead to thermal runaway or to stable conditions. We identify incipient thermal runaway as a necessary condition for the flash event, and hence identify the conditions under which this is likely to occur.Comment: 14 pages, 9 figure

Orbit growth for algebraic flip systems

Abstract. An algebraic flip system is an action of the infinite dihedral group by automorphisms of a compact abelian group X. In this paper, a fundamental structure theorem is established for irreducible algebraic flip sytems, that is, systems for which the only closed invariant subgroups of X are finite. Using irreducible systems as a foundation, for expansive algebraic flip systems, periodic point counting estimates are obtained that lead to the orbit growth estimate Ae hN � π(N) � Be hN where π(N) denotes the number of orbits of length at most N, A and B are positive constants and h is the topological entropy. 1. Background and main results Stemming from the seminal works of Ja. Sinaĭ [25] and G. Margulis [16], periodic orbits in dynamical systems have been investigated using orbit growth functions, with entropy featuring as a constant controlling the exponential growth. An extensive body of work now exists for both flows and discrete time dynamical systems (see for example, [21], [20], [27], [8], [9]). The study of orbit growth functions for dynamical group actions in general was pursued in [18] and [19]. This context encompasses the case of a single invertible transformation which corresponds to an action of the group G = Z. Let G be a finitely generated group acting on some set X, with the action written as x ↦ → g · x. The set L = L(G) of finite index subgroups of G becomes a locally finite poset with the order arising from inclusion. For L ∈ L, the number of L-periodic points in X is F(L) = |{x ∈ X: g · x = x for all g ∈ L}|. (1) An L-periodic orbit is the orbit of a point with stabilizer L, and the length of the orbit is denoted [L] = [G: L], the index of L in G. Assuming that there are only finitely many orbits of length n for each n � 1, the number of L-periodic orbits i

Tidal controls on the lithospheric thickness and topography of Io from magmatic segregation and volcanism modelling

Tidal heating is expected to impart significant, non-spherically-symmetric structure to Jupiter's volcanic moon Io. A signature of spatially variable tidal heating is generally sought in observations of surface heat fluxes or volcanic activity, an exploration complicated by the transient nature of volcanic events. The thickness of the lithosphere is expected to change over much longer timescales, and so may provide a robust link between surface observations and the tidal heating distribution. To predict long-wavelength lithospheric thickness variations, we couple three-dimensional tidal heating calculations to a suite of one-dimensional models of magmatic segregation and volcanic eruption. We find that the lithospheric thickness could either be correlated with the radially integrated heating rate, or weakly anti-correlated. Lithospheric thickness is correlated with radially integrated heating rate if magmatic intrusions form at a constant rate in the lithosphere, but is weakly anti-correlated if intrusions form at a rate proportional to the flux through volcanic conduits. Utilising a simple isostasy model we show how variations in lithospheric thickness can predict long-wavelength topography. The relationship between lithospheric thickness and topography depends on the difference in chemical density between the lithosphere and mantle. Assuming that this difference is small, we find that long-wavelength topography anti-correlates with lithospheric thickness. These results will allow future observations to critically evaluate models for Io's lithospheric structure, and enable their use in constraining the distribution of tidal heating.Comment: Published in Icaru

An experimental and numerical model for the release of acetone from decomposing EVA containing aluminium, magnesium or calcium hydroxide fire retardants

Recent studies have identified acetone as an unexpected pyrolysis product of EVA containing aluminium or magnesium hydroxide fire retardants. It is thought that the freshly formed, open-pored, metal oxide, a thermal decomposition product of the metal hydroxide, traps acetic acid released from EVA and catalyses its conversion to acetone. Such a ketonisation reaction is well-established but the intermediate steps that result in acetic acid conversion to acetone in the presence of a metal oxide, trapped within the polymer matrix, have not been reported. This study used three model metal acetates: aluminium acetate, magnesium acetate and calcium acetate, to chemically represent the proposed metal acetate intermediate complexes. This provides crucial information on the kinetics of acetic acid trapping and subsequent acetone release during decomposition studied by TGA-FTIR, which has been used to generate kinetic models within a pyrolysis programme (ThermaKin), in order to quantitatively understand the processes occurring in fire retardant EVA. The benefit of using metal acetates is that they are simple enough to allow isolation of the chemical process of interest from the complications of acetic acid release from EVA and transport through the polymer matri

How heat pumps and thermal energy storage can be used to manage wind power: A study of Ireland

Although energy for heating and cooling represents the largest proportion of demand, little progress towards meeting environmental targets has been achieved in these sectors. The recent rapid progress in integrating renewable energy into the electricity sector however, can help in decarbonising heat by electrification. This paper investigates the impacts and benefits of heat electrification in a wind dominated market by considering two options; with heat pumps, and with direct electric heating, both operated with energy storage. The Irish all-island electricity market is used as a case study. Modelling results reveal the significant potential of heat pump electrification, delivering at least two and three times less carbon emissions respectively, when compared with conventional options such as gas or oil for 20% of domestic sector of the All Ireland market. Heat electrification using direct, resistive heating systems is found to be the most carbon intensive method. Energy storage systems combined with heat pumps could deliver potentially significant benefits in terms of emissions reductions, efficient market operation and mitigating the impacts of variable renewable energy on baseload generation. The main barrier to heat electrification in the all island market is the absence of appropriate policy measures to support relevant technologies