1,029 research outputs found

    Wave Climate at Moffat Beach

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    The analysis of a series of wave recordings made at Moffat Beach, Queensland using an OSPOS wave recorder during 1963-1964 is described. This analysis included (i) the establishment of representative parameters for each wave recording; (ii) the determination of the frequency of occurrence of the representative parameters over the total recording period and (iii) the comparison of the recorded data with visual observations at Cape Moreton and the adjustment of the frequency curves to a longer more Queensland coast cannot be recommended.representative period of time.The results of the analysis provide confirmation of the\ua0applicability of the Rayleigh distribution to the short term wave\ua0height distribution within a given wave recording. On the other hand\ua0no definite conclusions are made concerning which theoretical\ua0representation of the long term wave height frequency of occurrence\ua0is to be preferred.The data analysed shows that at least four distinct types\ua0of wave conditions make up the overall wave climate in this area. The\ua0general wave height and period characteristics representative of these\ua0conditions together with seasonal variations are presented.The Moffat Beach wave data is compared with that obtained off\ua0the Gold Coast using Wave Rider buoys. Generally similar values of\ua0significant wave height are found but the wave periods are appreciably\ua0different. An analysis of possible explanations for this difference\ua0suggests that the filter effect due to pressure attenuation almost\ua0completely removes local wind generated seas from the OSPOS records.\ua0The question of a representative wave period for a given wave recording\ua0is considered and it is concluded that the use of the zero crossing\ua0period Tz\ua0for the analysis of unfiltered surface wave recordings of\ua0simultaneous sea and swell such as generally occurs off the southern\ua0Queensland coast cannot be recommended

    Beach and Dune Erosion Report M935/M936

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    A bilateral shear layer between two parallel Couette flows

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    We consider a shear layer of a kind not previously studied to our knowledge. Contrary to the classical free shear layer, the width of the shear zone does not vary in the streamwise direction but rather exhibits a lateral variation. Based on some simplifying assumptions, an analytic solution has been derived for the new shear layer. These assumptions have been justified by a comparison with numerical solutions of the full Navier-Stokes equations, which accord with the analytical solution to better than 1% in the entire domain. An explicit formula is found for the width of the shear zone as a function of wall-normal coordinate. This width is independent of wall velocities in the laminar regime. Preliminary results for a co-current laminar-turbulent shear layer in the same geometry are also presented. Shear-layer instabilities were then developed and resulted in an unsteady mixing zone at the interface between the two co-current streams.Comment: 6 pages, 7 figures. Accepted for publication in Phys. Rev.

    Engineering structures on the reefs and cays of the Great Barrier Reef and adjoining regions

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    Signal-to-signal-to-noise ratio of full-field Fourier domain optical coherence tomography: experiment

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    We report a new approach in optical coherence tomography (OCT) termed full-field Fourier-domain OCT (3F-OCT). A three-dimensional image of a sample is obtained by digital reconstruction of a three-dimensional data cube, acquired using a Fourier holography recording system illuminated with a swept-source. This paper presents theoretical and experimental study of the signal-to-noise ratio of the full-field approach versus serial image acquisition approach, represented by 3F-OCT and "flying-spot" OCT systems, respectively

    Interventions to Reduce Adult Nursing Turnover: A Systematic Review of Systematic Reviews.

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    Background: Nurse turnover is an issue of concern in health care systems internationally. Understanding which interventions are effective to reduce turnover rates is important to managers and health care organisations. Despite a plethora of reviews of such interventions, strength of evidence is hard to determine. Objective: We aimed to review literature on interventions to reduce turnover in nurses working in the adult health care services in developed economies. Method: We conducted an overview (systematic review of systematic reviews) using the Cochrane Database of Systematic Reviews, MEDLINE, EMBASE, Applied Social Sciences Index and Abstracts, CINAHL plus and SCOPUS and forward searching. We included reviews published between 1990 and January 2015 in English. We carried out parallel blinded selection, extraction of data and assessment of bias, using the Assessment of Multiple Systematic Reviews. We carried out a narrative synthesis. Results: Despite the large body of published reviews, only seven reviews met the inclusion criteria. These provide moderate quality review evidence, albeit from poorly controlled primary studies. They provide evidence of effect of a small number of interventions which decrease turnover or increase retention of nurses, these being preceptorship of new graduates and leadership for group cohesion. Conclusion: We highlight that a large body of reviews does not equate with a large body of high quality evidence. Agreement as to the measures and terminology to be used together with well-designed, funded primary research to provide robust evidence for nurse and human resource managers to base their nurse retention strategies on is urgently required

    Learning from the early adopters: developing the digital practitioner

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    This paper explores how Sharpe and Beetham’s Digital Literacies Framework which was derived to model students’ digital literacies, can be applied to lecturers’ digital literacy practices. Data from a small-scale phenomenological study of higher education lecturers who used Web 2.0 in their teaching and learning practices are used to examine if this pyramid model represents their motivations for adopting technology-enhanced learning in their pedagogic practices. The paper argues that whilst Sharpe and Beetham’s model has utility in many regards, these lecturers were mainly motivated by the desire to achieve their pedagogic goals rather than by a desire to become a digital practitioner

    One step multiderivative methods for first order ordinary differential equations

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    A family of one-step multiderivative methods based on Padé approximants to the exponential function is developed. The methods are extrapolated and analysed for use in PECE mode. Error constants and stability intervals are calculated and the combinations compared with well known linear multi-step combinations and combinations using high accuracy Newton-Cotes quadrature formulas as correctors. w926020
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