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  • 1
    Publication Date: 2023-01-30
    Description: Columnar jointing is best-known from formations in cooled lava, such as the Giant's Causeway, Devil's Postpile, or Fingal's Cave. However, these crack patterns also arise in other systems, most notably in dried starch. The data published here underlies research into the dynamical ordering of columnar joints, and the process by which they select their size or scale (Goehring and Morris, 2005; Goehring, Morris and Lin, 2006). The data set consists of nine X-ray tomographs of columnar joints in dried starch, presented as both the raw instrument data and as series of reconstructed cross-sectional images throughout the volume of the samples. There is a mixture of samples where the drying rate was monitored but not controlled, which results in columns that grow in size with depth, and samples where the drying rate of the starch was controlled by a feedback technique, which results in columns of constant size. A summary spreadsheet gives metadata associated with each sample, including the instrument settings during data acquisition. This data and the methods of its acquisition will be further detailed in an accompanying data publication, which will also include details of 3D reconstructions of columnar joints in various geophysical settings in the UK and Japan.
    Keywords: columnar jointing; Columnar joints; cracks; File format; File name; File size; fracture; tomography; Uniform resource locator/link to file
    Type: Dataset
    Format: text/tab-separated-values, 76 data points
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  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 11 (1999), S. 3613-3628 
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We investigate the linear stability of a thin, suspended, annular film of conducting fluid with a voltage difference applied between its inner and outer edges. For a sufficiently large voltage, such a film is unstable to radially driven electroconvection due to charges which develop on its free surfaces. The film can also be subjected to a Couette shear by rotating its inner edge. This combination is experimentally realized using films of smectic A liquid crystals. In the absence of shear, the convective flow consists of a stationary, azimuthally one-dimensional (1D) pattern of symmetric, counter-rotating vortex pairs. When Couette flow is applied, an azimuthally traveling pattern results. When viewed in a co-rotating frame, the traveling pattern consists of pairs of asymmetric vortices. We calculate the neutral stability boundary for arbitrary radius ratio α and Reynolds number Re of the shear flow, and obtain the critical control parameter Rc(α,Re) and the critical azimuthal mode number mc(α,Re). The Couette flow suppresses the onset of electroconvection, so that Rc(α,Re)〉Rc(α,0). The calculated suppression is compared with experiments performed at α=0.56 and 0≤Re≤0.22. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 67 (1996), S. 2043-2067 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We review the history of experimental work on Rayleigh–Bénard convection in gases, and then describe a modern apparatus that has been used in our experiments on gas convection. This system allows for the study of patterns in a cell with an aspect ratio (cell radius/fluid layer depth) as large as 100, with the cell thickness uniform to a fraction of a μm, and with the pressure controlled at the level of one part in 105. This level of control can yield a stability of the critical temperature difference for the convective onset of better than one part in 104. The convection patterns are visualized and the temperature field can be inferred using the shadowgraph technique. We describe the flow visualization and image processing necessary for this. Some interesting results obtained with the system are briefly summarized. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of statistical physics 64 (1991), S. 1025-1043 
    ISSN: 1572-9613
    Keywords: Convection ; pattern formation ; smectic liquid crystals ; two-dimensional liquid ; electroconvection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We report the results of experiments on electrically driven convection that occurs in a thin, freely suspended film of smectic A liquid crystal when an electric field is applied in the plane of the film. Convection in a vortex pattern is found above a well-defined critical voltage. The film behaves as a two-dimensional isotropic liquid: neither its thickness nor the director field are modified by the flow. We present measurements of the critical voltage at the onset of convection in two experimental configurations—one which allows the injection of charges into the film from the electrodes, and one which does not. When injection is present, the critical voltage for the onset of flow increases monotonically with increasing frequency of applied field. With no injection, there is no instability at DC and the critical voltage diverges there. The nature of the flow pattern observed at onset changes with frequency. Below a certain frequency the film flows in vortices that extend over the width of the film; above this frequency the flow is confined to two lines of smaller vortices localized along the electrodes. We present a simple discussion of the mechanisms which drive the convection.
    Type of Medium: Electronic Resource
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  • 5
    Publication Date: 2016-03-17
    Description: Objective. To test the effectiveness of adding a narrative leaflet to the current information material delivered by the NHS English colorectal cancer (CRC) screening programme on reducing socioeconomic inequalities in uptake. Participants. 150,417 adults (59–74 years) routinely invited to complete the guaiac Faecal Occult Blood test (gFOBt) in March 2013. Design. A cluster randomised controlled trial (ISRCTN74121020) to compare uptake between two arms. The control arm received the standard NHS CRC screening information material (SI) and the intervention arm received the standard information plus a supplementary narrative leaflet, which had previously been shown to increase screening intentions (SI + N). Between group comparisons were made for uptake overall and across socioeconomic status (SES). Results. Uptake was 57.7% and did not differ significantly between the two trial arms (SI: 58.5%; SI + N: 56.7%; odds ratio = 0.93; 95% confidence interval: 0.81–1.06; ). There was no interaction between group and SES quintile (). Conclusions. Adding a narrative leaflet to existing information materials does not reduce the SES gradient in uptake. Despite the benefits of using a pragmatic trial design, the need to add to, rather than replace, existing information may have limited the true value of an evidence-based intervention on behaviour.
    Print ISSN: 1687-6121
    Electronic ISSN: 1687-630X
    Topics: Medicine
    Published by Hindawi
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