159 research outputs found
Kraichnan-Leith-Batchelor similarity theory and two-dimensional inverse cascades
No full textWe study the scaling properties and Kraichnan-Leith-Batchelor (KLB) theory of forced inverse cascades in generalized two-dimensional (2D) fluids (-turbulence models) simulated at resolution . We consider (surface quasigeostrophic flow), (2D vorticity dynamics) and . The forcing scale is well-resolved, a direct cascade is present and there is no large-scale dissipation. Coherent vortices spanning a range of sizes, most larger than the forcing scale, are present for both and . The active scalar field for contains comparatively few and small vortices. The energy spectral slopes in the inverse cascade are steeper than the KLB prediction in all three systems. Since we stop the simulations well before the cascades have reached the domain scale, vortex formation and spectral steepening are not due to condensation effects; nor are they caused by large-scale dissipation, which is absent. One- and two-point pdfs, hyperflatness factors and structure functions indicate that the inverse cascades are intermittent and non-Gaussian over much of the inertial range for and , while the inverse cascade is much closer to Gaussian and non-intermittent. For the steep spectrum is close to that associated with enstrophy equipartition. Continuous wavelet analysis shows approximate KLB scaling () and () in the interstitial regions between the coherent vortices. Our results demonstrate that coherent vortex formation ( and ) and non-realizability () cause 2D inverse cascades to deviate from the KLB predictions, but that the flow between the vortices exhibits KLB scaling and non-intermittent statistics for and . The results will appear in \cite{BurgessEA2015}, which has been accepted to the \emph{Journal of Fluid Mechanics}
Ultra thin and transfer tattoo UHF RFID tags
No full textThis paper describes inkjet printing as a digital fabrication tool for the manufacture of RFID tags on flexible and porous substrates (i.e. paper). The RFID tag presented is a single layer, ultrathin UHF tag in the form of a transfer tattoo, [1] which evolved from ultra-thin, substrate insensitive tag designs, [2]. Operation has been demonstrated when mounted direct on the skin with initial read ranges in the region of 1m and subsequent improvements have enabled read range increases. The implications of ink sintering processes for paper based transfer tattoos will be discussed as specifically applied to this work, [3], and resulting patch conductivities and read ranges highlighted for tags printed on tattoo transfer paper, [4]. Recent developments in selective ink layering will be outlined to illustrate the benefits to cost effective fabrication and efficient tattoo patch operation. Finally, work integrating additional components to improve transponder efficiency will be presented and leading to the concept of an ultra-thin battery for power assisted tagging where on-skin read ranges of 6m are possible. The issues for fabrication will be discussed for deposition and fabrication of such ultra-low profile sensitive tattoo tags.
1. M. Ziai and J. Batchelor, Temporary On-Skin passive UHF RFID Transfer Tag, IEEE Transactions on Antennas and Propag., 2011, 59(10), 3565.
2. M. Ziai and J. Batchelor, Thin ultra high-frequency platform insensitive radio frequency identification tags, IET Microw. Antennas Propag., 2010, vol. 4, pp. 390–398.
3. V. Sanchez-Romaguera, M.B. Madec, S.G. Yeates, Ink-jet printing of conductive polymers for smart textiles and flexible electronics. Materials Research Society Symposium Proceedings, 2009, 1192E(Materials and Devices for Flexible and Stretchable Electronics), No pp. given, Paper #: 1192-PP14-04.
4. http://www.craftycomputerpaper.co.uk/.-Inkjet-Tattoo-Paper_CPJ316I.ht
Prandtl number effects on the decaying and the forced turbulence in stratified fluids
No full textEffects of high-Prandtl number density-stratifying scalar, i.e., active scalar, on decaying and forced turbulence in stratified fluids are investigated by numerical simulations. In decaying turbulence, potential energy spectrum of the high-Prandtl number active scalar (Pr=6) agrees with the kinetic energy spectrum even at small scales. In forced steady turbulence, these two spectra again approach each other at small scales. These phenomena, which are in disagreement with the Batchelor scaling for a high-Schmidt number passive scalar, occur at scales even smaller than the Ozmidov scale, suggesting that these effects would not be negligible in general
Turbulent super-diffusion as a ballistic cascade
No full textSince the pioneering work of Richardson in 1926, later refined by Batchelor and Obukhov in 1950, it is predicted that the rate of separation of pairs of fluid elements in turbulent flows with initial separation at inertial scales, grows ballistically first (Batchelor regime), before undergoing a transition towards a super-diffusive regime where the mean-square separation grows as (Richardson regime). Richardson empirically interpreted this super-diffusive regime in terms of a non-Fickian process with a scale dependent diffusion coefficient (the celebrated Richardson's ``4/3rd'' law). However, the actual physical mechanism at the origin of such a scale dependent diffusion coefficient remains unclear. The present work proposes a simple physical phenomenology for the Richardson super-diffusivity in turbulence based on a scale dependent \emph{ballistic} scenario rather than a scale dependent \emph{diffusive} scenario. It is shown that this phenomenology elucidates several aspects of turbulent dispersion: (i) it gives a simple physical explanation of the origin of the super diffusive Richardson regime as an iterative cascade of scale-dependent ballistic separations, (ii) it simply relates the Richardson constant to the Kolmogorov constant (and eventually to a ballistic persistence parameter), (iii) it gives a simple physical interpretation of the non-Fickian scale-dependent diffusivity coefficient as originally proposed by Richardson and (iv) a further extension of the phenomenology, taking into account higher order corrections to the local ballisitic motion, gives a robust interpretation of the assymetry between forward and backward dispersion, with an explicit connection to the energy flux accross scales
Eighteenth Century Journals V
No full textPart V of Adam Matthew Digital’s Eighteenth-Century Journals (ECJ) subscription online resource. Eighteenth-Century Journals V offers a complete and full-text searchable digitisation of the Lady’s Magazine (1770-1832) with secondary resources. Jennie Batchelor was Consultant Editor for Eighteenth-Century Journals V and the author of its scholarly introduction. ECJ V also features (on open access, not behind the subscription paywall) ‘The Lady’s Magazine Index’, co-authored with Koenraad Claes and Jenny DiPlacidi. The ‘Index’ was a key output of Batchelor’s Leverhulme Trust funded ‘Lady’s Magazine (1770-1818): The Emergence of a Genre’ project (2014-16). Adam Matthew converted Batchelor’s Excel database into a web database as an additional resource in ECJ V
A comparable cross-system bank productivity measure: Empirical evidence from the Malaysian dual banking system
No full textThis thesis seeks to fill a void in the banking performance literature by (1) proposing a cross-system bank productivity assessment methodology that can be applied to both conventional and Islamic banking and (2) implementing this methodology on a dual banking system to gauge the comparable productivity of Islamic and conventional banks relative to one another in a banking system that has experienced deregulation and consolidation. The growing significance of Islamic banking cannot be overlooked as its growth in recent years has significantly outpaced conventional banking. This new banking duality trend profoundly impacts the relative competitiveness of both banking systems and this in turn, may significantly affect the allocation of scarce financial resources between conventional and Islamic banking
The works of Mr. Congreve : in two volumes; to which is prefixed The Life of the author.
No full textv.1. The life of the author. The old batchelor. The double dealer. Love for love. -- v.2. The mourning bride. The way of the world. The judgment of Paris. Semele. Poems on several occasions.Mode of access: Internet
George Keith Batchelor's Interaction with Chinese Fluid Dynamicists and Inspirational Influence: a historical perspective
No full textGeorge Keith Batchelor (1920–2000, FRS 1957) was a towering figure in the twentieth century international fluid mechanics community. Much has been written about him since his death. This article presents an account of Batchelor's early interactions and relationships with Chinese fluid dynamicists and his continuing inspirational influence on them, which have not yet been documented in English. The theory of homogeneous turbulence, to which Batchelor contributed greatly, has had both indirect and direct inspirational influence on generations of Chinese fluid dynamicists, as they have sought to make their own contributions. Batchelor made visits to China in 1980 and 1983. His first ice-breaking trip to China in April 1980 is of special importance to Sino-British fluid mechanics and to China, even though Batchelor did not speak about turbulence but instead about his more recent research interest, microhydrodynamics. Batchelor's philosophical view of applied mathematics (fluid mechanics)—that ‘You have got to inject some physical thinking as well as mathematical thinking’—has had great inspirational influence on generations of fluid dynamicists in the UK, in China, and around the world. Batchelor's generosity of spirit and frugality of habit is warmly remembered by his students and Chinese friends. The author presents details of Batchelor's interaction with Chinese fluid dynamicists in the 1980s within the general context of the scientific relationship between China and the UK.</p
ERAS in Cardiothoracic Surgery and Digital Chest Drains
No full textEnhanced Recovery After Surgery (ERAS) is a perioperative protocol that places the patient at the center of all medical decisions. It is designed to reduce stress for the patient, alleviate the amount of pain they experience, and crucially, speed up the recovery and mobilization process, where removing invasive lines and drains as soon as possible is essential.
During the Seventh ERAS World Congress, held in Liverpool, UK, in early May 2019, the myriad benefits of the protocol for both patients and the perioperative care team were discussed by three experts: Olle Ljungqvist, Professor of Surgery at Örebro University, Sweden, and co-founder and current president of the ERAS® Society; Tim Batchelor, a thoracic surgeon from Bristol in the UK and lead author of the recently published ERAS® Society/ESTS guidelines for lung surgery; and Jim Coates, clinical research fellow in cardiothoracic anesthesia and principal investigator of ERAS for heart patients at the James Cook University Hospital in Middlesbrough, UK. The group discusses the implementation of ERAS protocols, how patients benefit from ERAS approaches, and how digital chest drains fit into the ERAS philosophy.Jim Coates directed a feasibility study for using digital chest drains during an ERAS program in Middelsbrough, UK, work that was supported by a grant from Medela. Additionally, the filming of this roundtable was organized and paid for by Medela; the panelists were not reimbursed for their participation.</p
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