Design of self-turning controllers for two terminal HVDC link

This paper presents the design of self-tuning controllers for a two terminal HVDC link. The controllers are designed utilizing a novel discrete-time converter model based on multirate sampling. The nature of converter firing system necessitates the development of a two-step ahead self-tuning control strategy. A two terminal HVDC system study has been carried out to show the effectiveness of the control strategies proposed which include the design of minimum variance controller, pole assigned controller and PLQG controller. The coordinated control of a two terminal HVDC system has been established deriving the signal from inverter end current and voltage which has been estimated based on the measurements of rectifier end quantities only realized through the robust reduced order observer. A well known scaled down sample system data has been selected for studies and the controllers designed have been tested for worst conditions. The performance of self-tuning controllers has been evaluated through digital simulation.

Numerical and experimental investigation of wedge tip radius effect on wedge plasmons

We report numerical analysis and experimental observation of strongly localized plasmons guided by triangular metal wedges and pay special attention to the effect of smooth (nonzero radius) tips. Dispersion, dissipation, and field structure of such wedge plasmons are analyzed using the compact two-dimensional finite-difference time-domain algorithm. Experimental observation is conducted by the end-fire excitation and near-field scanning optical microscope detection of the predicted plasmons on 40°silver nanowedges with the wedge tip radii of 20, 85, and 125 nm that were fabricated by the focused-ion beam method. The effect of smoothing wedge tips is shown to be similar to that of increasing wedge angle. Increasing wedge angle or wedge tip radius results in increasing propagation distance at the same time as decreasing field localization (decreasing wave number). Quantitative differences between the theoretical and experimental propagation distances are suggested to be due to a contribution of scattered bulk and surface waves near the excitation region as well as the addition of losses due to surface roughness. The theoretical and measured propagation distances are several plasmon wavelengths and are useful for a range of nano-optical applications

Accurate series solutions for gravity-driven Stokes waves

In the past, high order series expansion techniques have been used to study the nonlinear equations that govern the form of periodic Stokes waves moving steadily on the surface of an inviscid fluid. In the present study, two such series solutions are recomputed using exact arithmetic, eliminating any loss of accuracy due to accumulation of round-off error, allowing a much greater number of terms to be found with confidence. It is shown that higher order behaviour of series generated by the solution casts doubt over arguments that rely on estimating the series’ radius of convergence. Further, the exact nature of the series is used to shed light on the unusual nature of convergence of higher order Pade approximants near the highest wave. Finally, it is concluded that, provided exact values are used in the series, these Pade approximants prove very effective in successfully predicting three turning points in both the dispersion relation and the total energy.

Turning Around Talipes: Nursing Considerations

The management of congenital talipes equinovarus (TEV) has received much clinical and research attention within the disciplines of medicine and physiotherapy. However, few articles have been published about the role of the registered nurse in contributing to the optimum health and wellbeing of the child and family presenting for assessment and treatment of the condition. Much of the most intense treatment for TEV occurs in the first few weeks of the child’s life; a time of critical growth and development when the infant is both sensitive and vulnerable to the environment within which it is nurtured. This is also a crucial time for developing a secure attachment to the caregiver and nurses can assist parents in optimising their infant’s opportunities for a secure attachment relationship. This paper thus provides an overview of the medical and physiotherapy management of TEV and highlights the role nurses have in providing nursing care and psycho-social support to parents of infants with TEV, in areas such as the maintenance of skin integrity and circulation, providing effective pain relief, and optimising growth, development, and a secure attachment relationship. Congenital TEV or 'club foot' is one of the most common congenital orthopaedic anomalies of infants. In Queensland in 2000, in approximately 50,000 births, 244 infants were born with talipes; almost five infants per 1000 births. National statistics are not as specific, with coding providing only 'other lower limb' as the category that would encompass talipes; the 1997 national incidence of such lower limb congenital malformations is reported as 1.7 per 10,000 births 1.

Binang gurri: turning a deaf ear to indigenous hearing loss

Objective: This paper asks whether Indigenous health policies might be improved if governments listened to Indigenous voices, both Australian and those who drafted the Declaration on the Rights of Indigenous Peoples, 2007. Methods: A fundamental tenet of the Declaration, which Australia endorsed in 2009, is respect for Indigenous knowledge and voice. The author analyses legal, cultural and historical sources for evidence of this respect. The metaphorical and empirical framework of the analysis is the epidemic of otitis media among Indigenous children. Results: A survey of Indigenous advice about health clearly demonstrates that access to their land and respect for the diversity of Indigenous cultures should inform health policies. Despite, however, claiming to consult Indigenous peoples, policy-makers have not been listening. In many Indigenous languages not listening, or ‘bad ears’, has connotations of disrespect. Conclusions: By turning a deaf ear to Indigenous knowledge governments are undermining any respect Indigenous peoples may have for them and their policies. A new approach is needed. Implications: The Declaration on the Rights of Indigenous Peoples can provide federal, state and territory governments with benchmarks against which health policy can be developed and implemented. Authentic consultation could restore Indigenous confidence in government policies.

Preventing injuries on a state-wide basis : researchers and parliamentary committees are partners in turning injury prevention and safety research into practice and policy

Context: Parliamentary committees established in Westminster parliaments, such as Queensland, provide a cross-party structure that enables them to recommend policy and legislative changes that may otherwise be difficult for one party to recommend. The overall parliamentary committee process tends to be more cooperative and less adversarial than the main chamber of parliament and, as a result, this process permits parliamentary committees to make recommendations more on the available research evidence and less on political or party considerations. Objectives: This paper considers the contributions that parliamentary committees in Queensland have made in the past in the areas of road safety, drug use as well as organ and tissue donation. The paper also discusses the importance of researchers actively engaging with parliamentary committees to ensure the best evidence based policy outcomes. Key messages: In the past, parliamentary committees have successfully facilitated important safety changes with many committee recommendations based on research results. In order to maximise the benefits of the parliamentary committee process it is essential that researchers inform committees about their work and become key stakeholders in the inquiry process. Researchers can keep committees informed by making submissions to their inquiries, responding to requests for information and appearing as witnesses at public hearings. Researchers should emphasise the key findings and implications of their research as well as considering the jurisdictional implications and political consequences. It is important that researchers understand the differences between lobbying and providing informed recommendations when interacting with committees. Discussion and conclusions: Parliamentary committees in Queensland have successfully assisted in the introduction of evidence based policy and legislation. In order to present best practice recommendations, committees rely on the evidence presented to them including the results of researchers. Actively engaging with parliamentary committees will help researchers to turn their results into practice with a corresponding decrease in injuries and fatalities. Developing an understanding of parliamentary committees, and the typical inquiry process used by these committees, will help researchers to present their research results in a manner that will encourage the adoption of their ideas by parliamentary committees, the presentation of these results as recommendations within the report and the subsequent enactment of the committee’s recommendations by the government.

Using turning technologies to engage tutors and facilitate effective marking and moderation in large classes

Audience Response Systems (ARS) have been successfully used by academics to facilitate student learning and engagement, particularly in large lecture settings. However, in large core subjects a key challenge is not only to engage students, but also to engage large and diverse teaching teams in order to ensure a consistent approach to grading assessments. This paper provides an insight into the ways in which ARS can be used to encourage participation by tutors in marking and moderation meetings. It concludes that ARS can improve the consistency of grading and the quality of feedback provided to students.

Turning histories into futures : assessment for learning as a field of exchange

Standardised testing does not recognise the creativity and skills of marginalised youth. Young people who come to the Edmund Rice Education Australia Flexible Learning Centre Network (EREAFLCN) in Australia arrive with forms of cultural capital that are not valued in the field of education and employment. This is not to say that young people‟s different modes of cultural capital have no value, but rather that such funds of knowledge, repertoires and cultural capital are not valued by the powerful agents in educational and employment fields. The forms of cultural capital which are valued by these institutions are measurable in certain structured formats which are largely inaccessible for what is seen in Australia to be a growing segment of the community. How then can the inherent value of traditionally unorthodox - yet often intricate, adroit, ingenious, and astute - versions of cultural capital evident in the habitus of many young people be made to count, be recognised, be valuated? Can a process of educational assessment be used as a marketplace, a field of capital exchange? This paper reports on the development of an innovative approach to assessment in an alternative education institution designed for the re-engagement of „at risk‟ youth who have left formal schooling. In order to capture the broad range of students‟ cultural and social capital, an electronic portfolio system (EPS) is under trial. The model draws on categories from sociological models of capital and reconceptualises the eportfolio as a sociocultural zone of learning and development. Initial results from the trial show a general tendency towards engagement with the EPS and potential for the attainment of socially valued cultural capital in the form of school credentials.

More is not necessarily better. A biomechanical study on distal screw numbers in volar locking distal radius plates

INTRODUCTION: Currently available volar locking plates for the treatment of distal radius fractures incorporate at least two distal screw rows for fixation of the metaphyseal fragment and have a variable-angle locking mechanism which allows placement of the screws in various directions There is, however no evidence that these plates translate into better outcomes or have superior biomechanical properties to first generation plates, which had a single distal screw row and fixed-angle locking. The aim of our biomechanical study was to compare fixed-angle single-row plates with variable-angle multi-row plates to clarify the optimal number of locking screws. MATERIALS AND METHODS: Five different plate-screw combinations of three different manufacturers were tested, each group consisting of five synthetic fourth generation distal radius bones. An AO type C2 fracture was created and the fractures were plated according to each manufacturer's recommendations. The specimens then underwent cyclic and load-to-failure testing. An optical motion analysis system was used to detect displacement of fragments. RESULTS: No significant differences were detected after cyclic loading as well as after load-to-failure testing, neither in regard to axial deformation, implant rigidity or maximum displacement. The fixed-angle single-row plate showed the highest pre-test rigidity, least increase in post-testing rigidity and highest load-to-failure rigidity and least radial shortening. The radial shortening of plates with two distal screw rows was 3.1 and 4.3 times higher, respectively, than that of the fixed-angle single-row plate. CONCLUSION: The results of our study indicate that two distal screw rows do not add to construct rigidity and resistance against loss of reduction. Well conducted clinical studies based on the findings of biomechanical studies are necessary to determine the optimal number of screws necessary to achieve reproducibly good results in the treatment of distal radius fractures.