Engineering

Publication Search Results

Now showing 1 - 10 of 12
  • (2009) Hawkes, Evatt; Sankaran, Ramanan; Chen, Jacqueline; Kasier, Sebastian; Frank, Jonathan
    Journal Article
    The difficulty of experimental measurements of the scalar dissipation rate in turbulent flames has required researchers to estimate the true three-dimensional (3D) scalar dissipation rate from one-dimensional (1D) or two-dimensional (2D) gradient measurements. In doing so, some relationship must be assumed between the true values and their lower dimensional approximations. We develop these relationships by assuming a form for the statistics of the gradient vector orientation, which enables several new results to be obtained and the true 3D scalar dissipation PDF to be reconstructed from the lower-dimensional approximations. We use direct numerical simulations (DNS) of turbulent plane jet flames to examine the orientation statistics, and verify our assumptions and final results. We develop and validate new theoretical relationships between the lower-dimensional and true moments of the scalar dissipation PDF assuming a log-normal true PDF. We compare PDFs reconstructed from lower-dimensional gradient projections with the true values and find an excellent agreement for a 2D simulated measurement and also for a 1D simulated measurement perpendicular to the mean flow variations. Comparisons of PDFs of thermal dissipation from DNS with those obtained via reconstruction from 2D experimental measurements show a very close match, indicating this PDF is not unique to a particular flame configuration. We develop a technique to reconstruct the joint PDF of the scalar dissipation and any other scalar, such as chemical species or temperature. Reconstructed conditional means of the hydroxyl mass fraction are compared with the true values and an excellent agreement is obtained.

  • (2009) Thiruvaran, T; Nosratighods, M; Ambikairajah, E; Epps, J
    Journal Article
    Recently, subband frame-averaged frequency modulation (FM) as a complementary feature to amplitude-based features for several speech based classification problems including speaker recognition has shown promise. One problem with using FM extraction in practical implementations is computational complexity. Proposed is a computationally efficient method to estimate the frame-averaged FM component in a novel manner, using zero crossing counts and the zero crossing counts of the differentiated signal. FM components, extracted from subband speech signals using the proposed method, form a feature vector. Speaker recognition experiments conducted on the NIST 2008 telephone database show that the proposed method successfully augments mel frequency cepstrum coefficients (MFCCs) to improve performance, obtaining 17% relative reductions in equal error rates when compared with an MFCC-based system.

  • (2009) Sohn, J.H.; Pioggia, G.; Craig, I.P.; Stuetz, Richard M.; Atzeni, M.G.
    Journal Article
    Identification of major contributors to odour annoyance in areas with multiple emission sources is necessary to address and resolve odour disputes. In an effort to develop an appropriate tool for this task, odour samples were collected on-site at a piggery and an abattoir (the major odour sources in the area) and at surrounding off-site areas, then analysed using a commercial non-specific chemical sensor array to develop an odour fingerprint database. The developed odour fingerprint database was analysed using two pattern recognition algorithms including a partial least squares-discriminant analysis (PLS-DA) and a Kohonen self-organising map (KSOM). The KSOM model could identify odour samples sourced from the piggery shed 15, piggery pond 8, piggery pond 9, abattoir, motel and others with mean percentage values of 77.5, 65.0, 90.2, 75.7, 44.8 and 64.6%, respectively.

  • (2009) Henderson, R.K; Baker, A; Murphy, K.R; Hambly, A; Stuetz, Richard M.; Khan, S.J
    Journal Article
    A rapid, highly sensitive and selective detector is urgently required to detect contamination events in recycled water systems – for example, cross-connection events in dual reticulation pipes that recycle advanced treated sewage effluent – as existing technologies, including total organic carbon and conductivity monitoring, cannot always provide the sensitivity required. Fluorescence spectroscopy has been suggested as a potential monitoring tool given its high sensitivity and selectivity. A review of recent literature demonstrates that by monitoring the fluorescence of dissolved organic matter (DOM), the ratios of humic-like (Peak C) and protein-like (Peak T) fluorescence peaks can be used to identify trace sewage contamination in river waters and estuaries, a situation analogous to contamination detection in recycled water systems. Additionally, strong correlations have been shown between Peak T and biochemical oxygen demand (BOD) in rivers, which is indicative of water impacted by microbial activity and therefore of sewage impacted systems. Hence, this review concludes that the sensitive detection of contamination events in recycled water systems may be achieved by monitoring Peak T and/or Peak C fluorescence. However, in such systems, effluent is treated to a high standard resulting in much lower DOM concentrations and the impact of these advanced treatment processes on Peaks T and C fluorescence is largely unknown and requires investigation. This review has highlighted that further work is also required to determine (a) the stability and distinctiveness of recycled water fluorescence in relation to the treatment processes utilised, (b) the impact of matrix effects, particularly the impact of oxidation, (c) calibration issues for online monitoring, and (d) the advanced data analytical techniques required, if any, to improve detection of contamination events.

  • (2009) Wong, Anna; Marcus, Nadine; Ayres, Paul; Sweller, John
    Journal Article
    Based on the assumption of a working memory processor devoted to human movement, cognitive load theory is used to explore some conditions under which animated instructions are hypothesised to be more effective for learning than equivalent static graphics. Using paper-folding tasks dealing with human movement, results from three experiments confirmed our hypothesis, indicating a superiority of animation over static graphics. These results are discussed in terms of a working memory processor that may be facilitated by our mirror-neuron system and may explain why animated instructional animations are superior to static graphics for cognitively based tasks that involve human movement.

  • (2009) Corkish, Richard Paul
    Journal Article
    The current photovoltaics education offerings available in Australia are described. A specialist photovoltaics engineering bachelor degree and majors within general engineering degrees are available. Technical training programs are offered at various locations, some focussed on photovoltaic system designer and installer accreditation requirements. Teaching support material will be introduced in 2008 into the senior secondary school Engineering Studies subject, offered in the state of New South Wales.

  • (2009) Antony, Alice; Bassendeh, Mojgan; Phillips, Ross; Richardson, Des; Leslie, Greg
    Conference Paper

  • (2009) Quinnell, Rosanne; Russell, Carol; Thompson, Rachel; Nancy, Marshall; Cowley, Jill
    Conference Paper
    A raft of models and definitions of SoTL exist and the best appear to transcend disciplinary contexts, and are sufficiently robust for academics to measure scholarly practices. Critical engagement with the scholarly literature is necessary for academics to gain a realistic view of where their work practices are situated within the scholarly domain. Because academic staff are disciplinary experts they are best placed to comment on whether the models of scholarship describe the scholarship of learning and teaching within the context of their own disciplines as well as within the confines of the Australian higher education sector. This paper pushes the existing debates on reconciling what evidence of scholarship in the disciplines actually is and what is considered valid, and in doing so uncovers why the process of reconciliation, between current practice and supporting evidence, remains elusive. Higher education academics need to identify and reconcile tacit disciplinary knowledge with their SoTL approach in order to unpack the complexity and value of their practices. Enabling academic staff to annotate their activities, roles and accomplishments and then map these items onto the various models of scholarship will enrich the status of scholarship of teaching and learning within the higher education sector.

  • (2009) Chen, Gaojian; Amajjahe, S.; Stenzel, M.H.
    Journal Article
    Homopolymer and block copolymer bearing carbohydrate side chain functionality were obtained by grafting glucothiose onto alkene functional scaffolds via a thiol-ene click reaction and the resulting copolymer was used to form thermo-responsive micelles as a potential drug carrier.

  • (2009) IU, Chi Kin; Bradford, Mark; Chen, Wei Fah
    Journal Article
    Composite steel-concrete structures experience non-linear effects which arise from both instability-related geometric non-linearity and from material non-linearity in all of their component members. This paper therefore presents a numerical procedure capable of addressing geometric and material non-linearities at the strength limit state based on the refined plastic hinge method. The refined plastic hinge approach models the elasto-gradual-plastic material non-linearity with strain-hardening under the interaction of bending and axial actions. This produces a benign method for a beam–column composite element under general loading cases. Another main feature of this paper is that, for members containing a point of contraflexure, its location is determined and a node is then located at this position to reproduce the real flexural behaviour and associated material non-linearity of the member. The formulation with the refined plastic hinge approach is efficacious and robust, and so a full frame analysis incorporating geometric and material non-linearity is tractable. Following development of the theory, its application is illustrated with a number of varied examples.