The parameterisation of turbulence in the marine environment

There are many problems in the fields of flow modelling around structures and tidal stream energy yield analysis which require a thorough understanding of the turbulent and time-averaged flow speeds in marine environments. In this paper we examine the relationship between the turbulence intensity and mean tidal flow speed at a potential tidal stream power site. We report data from the Humber Estuary wherein an Acoustic Doppler Current Profiler were used to capture vertical profiles of the high frequency and mean tidal flow speeds throughout Spring and Neap, Flood and Ebb cycles. We show not only that our results extend earlier work but also suggest that the turbulence intensity, IT, can be described parametrically in terms of the mean flow, U, by an inverse power function IT = α Uᵖ where the coefficient appears to be dependent upon the anisotropic nature of the turbulence. For the data reported here, the coefficient has value of about 17–18 and the exponent lies between −0.6 and −1.0. Confirmation of this relationship should not only improve engineering design work and energy yield analyses in turbulent tidal flows but also be applicable to other problems such as the prediction of sediment mass transport and pollution dispersal in estuarine management studies

Survey of surveys: a survey of citizen-based surveys conducted by provincial and local government in Gauteng

October 2012This publication contains the findings from a GCRO survey of citizen-based surveys undertaken at provincial and local government level in Gauteng. The Survey was conducted in order to understand the efficiencies at play with different role players conducting similar exercises at similar points in time.Conducted for the Gauteng City-Region Observatory (GCRO) by Ross Jenning

Empirical modelling of turbulence and wave-current interaction in tidal streams

The successful development of the tidal stream power industry fundamentally relies on a thorough, quantitative understanding of the available resource. Numerical simulations and laboratory flume experiments have demonstrated that increased turbulence and wave-induced motion can have detrimental effects on the fatigue and performance of prototype tidal stream turbines (TSTs). Knowledge of the relationships between mean current velocity, turbulence and surface waves is limited and presents a significant research gap. This research makes a significant contribution to the field by developing empirical models from in situ data collected within the Humber Estuary. These models estimate the turbulence strength and intensity at a point and through depth given a mean current velocity.An 18-day deployment of bed-mounted directional wave recorders (DWR) at Foul Holme Spit simultaneously recorded two-dimensional flow velocities and surface wave parameters. Static, vessel-mounted, acoustic Doppler current profiler (ADCP) surveys recorded turbulence through depth near St. Andrews Dock.The analyses revealed distinct relationships between the mean current velocity, turbulence strength and turbulence intensity at a point which are comparable to recently published results. The inter-tidal relationship between streamwise mean current velocity and turbulence strength is modelled at a point using power regression where α is 0.13 and β is 0.72 with an R² value of 0.8721. The inter-tidal relationship between streamwise mean current velocity and turbulence intensity is modelled at a point using power regression where γ is 14.315 and δ is -0.2316 with an R² value of 0.5482. A newly defined empirical relationship between depth-averaged mean current velocity and turbulence intensity is modelled using power regression where ε is 17.75 and ζ is -0.94 with an R² value of 0.7912. The models derived at a point are tested on the data collected through depth and exhibited strong predictive capability within the order of 0.1 ms-1. The exponential approximation of wave-induced velocity, proposed by Soulsby (2006), was tested and shown to be inappropriate for estimating wave-induced velocities at this scale. A comparative spectral analysis between DWR sample bursts determined that spikes in the turbulence spectra can be attributed to surface wave parameters, thus validating the conceptual model proposed by Soulsby and Humphrey (1990)

Mass Illuminations:Jennings, Madge, Rimbaud and the 'Popular' Prose Poem

The importance of the Mass-Observation social research project to post-war British literature can be traced to the founding involvement of two poets, Humphrey Jennings and Charles Madge. Their experimentation with the possibility of a prose-based poetry in the mid-Thirties has already been linked to the example of Surrealism. Here, it is argued that they were also strongly influenced by Rimbaud’s Une Saison en Enfer (1873) and Illuminations (1872-74). Madge’s prose poem ‘Bourgeois News’ uses textual collage to create a Rimbaldian vision of the ‘parade sauvage’ of late imperial Britain, which strikingly anticipates the work of more recent British prose poets such as Rod Mengham and Tony Lopez. In conclusion, archival evidence is used to support the hypothesis that Madge composed an anoymous news article, influenced by his reading of Rimbaud, as an illustration of his belief that newspapers contained the potential for a revolutionary new form of ‘popular poetry’

Mindfulness training: success in reducing first year health professional students' study and exam related stress

Purpose: Students enrolling in high stakes, undergraduate entry, professional programs like medicine, dentistry and pharmacy may struggle to effectively achieve the transition from high school. This often results in high levels of mental distress. Method: The College of Medicine and Dentistry at James Cook University have implemented a health professional self-care program (HPSC) with an aim of helping students recognize stressors and develop coping strategies. The HPSC program has been running for three years in the first year of each of the three courses. The HPSC program was delivered as a series of eight sessions focusing on evidenced based theory with some time for practicing coping strategies. Five-point Likert scale surveys were administered prior to commencing the program and after completion. Results: Across the College, students reported significantly improved abilities to reduce study and exam related stress and develop effective coping skills. These results were more pronounced in students that practiced techniques of mindfulness. Discussion: The HPSC program changed student perceptions in being able to improve their own self-care and reduced study and exam related stress

Reviews and contestability: new directions for Defence

Overview: The First Principles Review of Defence is arguably the most significant review of the defence establishment since the 1973 re-organisation led by Sir Arthur Tange. This Strategic Insights brings together a series of contributions to ASPI’s blog The Strategist written by ten experts with long experience and broad knowledge of Australia’s defence bureaucracy. They bring a wealth of different perspectives and point to significant challenges ahead for Defence if the reforms proposed by the First Principles Review are to succeed

Eradication of two incursions of the Red Imported Fire Ant in Queensland, Australia

Of the five known incursions of the highly invasive Red Imported Fire Ant in Australia, two are regarded to have been eradicated. As treatment efforts continue, and the programme evolves and new tools become available, eradication is still considered to be feasible for the remaining Red Imported Fire Ant populations with long-term commitment and support

Understanding the faint red galaxy population using large-scale clustering measurements from SDSS DR7

We use data from the SDSS to investigate the evolution of the large-scale galaxy bias as a function of luminosity for red galaxies. We carefully consider correlation functions of galaxies selected from both photometric and spectroscopic data, and cross-correlations between them, to obtain multiple measurements of the large-scale bias. We find, for our most robust analyses, a strong increase in bias with luminosity for the most luminous galaxies, an intermediate regime where bias does not evolve strongly over a range of two magnitudes in galaxy luminosity, and no evidence for an upturn in bias for fainter red galaxies. Previous work has found an increase in bias to low luminosities that has been widely interpreted as being caused by a strong preference for red dwarf galaxies to be satellites in the most massive halos. We can recover such an upturn in bias to faint luminosities if we push our measurements to small scales, and include galaxy clustering measurements along the line-of-sight, where we expect non-linear effects to be the strongest. The results that we expect to be most robust suggest that the low luminosity population of red galaxies is not dominated by satellite galaxies occupying the most massive haloes.Comment: Matches version accepted by MNRA