A mathematical model of a large open fire

A mathematical model capable of predicting the detailed characteristics of large, liquid fuel, axisymmetric, pool fires is described. The predicted characteristics include spatial distributions of flame gas velocity, soot concentration and chemical specie concentrations including carbon monoxide, carbon dioxide, water, unreacted oxygen, unreacted fuel and nitrogen. Comparisons of the predictions with experimental values are also given

The influence of type of residence and habitual activity on lung function and body composition in children

The influence of type of residence and habitual activity on lung function and body composition in childre

Elasticity of an interfacial particle raft

We study the collective behaviour of a close packed monolayer of non-Brownian particles at a fluid-liquid interface. Such a particle raft forms a two-dimensional elastic solid and can support anisotropic stresses and strains, e.g. it buckles in uniaxial compression and cracks in tension. We characterise this solid in terms of a Young's modulus and Poisson ratio derived from simple theoretical considerations and show the validity of these estimates by using an experimental buckling assay to deduce the Young's modulus.Comment: 7 pages, 5 figure

Platybunus triangularis and Paroligolophus agrestis: two phalangids introduced to North America (Arachnida, Opiliones)

Volume: 2Start Page: 127End Page: 12

LV. The quality of the secondary ionization due to β rays

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Meanfield treatment of Bragg scattering from a Bose-Einstein condensate

A unified semiclassical treatment of Bragg scattering from Bose-Einstein condensates is presented. The formalism is based on the Gross-Pitaevskii equation driven by classical light fields far detuned from atomic resonance. An approximate analytic solution is obtained and provides quantitative understanding of the atomic momentum state oscillations, as well as a simple expression for the momentum linewidth of the scattering process. The validity regime of the analytic solution is derived, and tested by three dimensional cylindrically symmetric numerical simulations.Comment: 21 pages, 10 figures. Minor changes made to documen

From white elephant to Nobel Prize: Dennis Gabor’s wavefront reconstruction

Dennis Gabor devised a new concept for optical imaging in 1947 that went by a variety of names over the following decade: holoscopy, wavefront reconstruction, interference microscopy, diffraction microscopy and Gaboroscopy. A well-connected and creative research engineer, Gabor worked actively to publicize and exploit his concept, but the scheme failed to capture the interest of many researchers. Gabor’s theory was repeatedly deemed unintuitive and baffling; the technique was appraised by his contemporaries to be of dubious practicality and, at best, constrained to a narrow branch of science. By the late 1950s, Gabor’s subject had been assessed by its handful of practitioners to be a white elephant. Nevertheless, the concept was later rehabilitated by the research of Emmett Leith and Juris Upatnieks at the University of Michigan, and Yury Denisyuk at the Vavilov Institute in Leningrad. What had been judged a failure was recast as a success: evaluations of Gabor’s work were transformed during the 1960s, when it was represented as the foundation on which to construct the new and distinctly different subject of holography, a re-evaluation that gained the Nobel Prize for Physics for Gabor alone in 1971. This paper focuses on the difficulties experienced in constructing a meaningful subject, a practical application and a viable technical community from Gabor’s ideas during the decade 1947-1957

Aerodynamic Classification of Swept-Wing Ice Accretion

The continued design, certification and safe operation of swept-wing airplanes in icing conditions rely on the advancement of computational and experimental simulation methods for higher fidelity results over an increasing range of aircraft configurations and performance, and icing conditions. The current state-of-the-art in icing aerodynamics is mainly built upon a comprehensive understanding of two-dimensional geometries that does not currently exist for fundamentally three-dimensional geometries such as swept wings. The purpose of this report is to describe what is known of iced-swept-wing aerodynamics and to identify the type of research that is required to improve the current understanding. Following the method used in a previous review of iced-airfoil aerodynamics, this report proposes a classification of swept-wing ice accretion into four groups based upon unique flowfield attributes. These four groups are: ice roughness, horn ice, streamwise ice and spanwise-ridge ice. In the case of horn ice it is shown that a further subclassification of nominally 3D or highly 3D horn ice may be necessary. For all of the proposed ice-shape classifications, relatively little is known about the three-dimensional flowfield and even less about the effect of Reynolds number and Mach number on these flowfields. The classifications and supporting data presented in this report can serve as a starting point as new research explores swept-wing aerodynamics with ice shapes. As further results are available, it is expected that these classifications will need to be updated and revised

Achieving environmentally sustainable growing media for soilless plant cultivation systems – a review

Soilless cultivation is recognized globally for its ability to support efficient and intensive plant production. While production systems vary, most utilize a porous substrate or growing medium for plant provision of water and nutrients. Until relatively recently, the main drivers for the selection of the component materials in growing media were largely based on performance and economic considerations. However, increasing concern over the environmental impacts of some commonly used materials, has led researchers to identify and assess more environmentally sound alternatives. There has been an understandable focus on renewable materials from agricultural, industrial and municipal waste streams; while many of these show promise at an experimental level, few have been taken up on a significant scale. To ensure continued growth and sustainable development of soilless cultivation, it is vital that effective and environmentally sustainable materials for growing media are identified. Here we describe the factors influencing material selection, and review the most commonly used organic materials in relation to these. We summarise some of the renewable, primary and waste stream materials that have been investigated to date, highlighting the benefits and challenges associated with their uptake. In response to the need for researchers to better identify promising new materials, we present an evidence-based argument for a more consistent approach to characterising growing media and for a clearer understanding of the practical and economic realities of modern soilless cultivation systems