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10W Injection-Locked CW Nd:YAG laser
(2004) Hosken, D.; Mudge, D.; Veitch, P.; Munch, J.; LIGO Scientific Collaboration Meeting (2004 : Livingston, Louisiana)
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10W Nd:YAG laser for gravitational wave interferometry
(2005) Hosken, D.; Mudge, D.; Veitch, P.; Munch, J.; Australasian Conference on Optics, Lasers and Spectroscopy (7th : 2005 : Rotorua, New Zealand)
We shall describe the development and characterisation of an injection-locked 10W Nd:YAG laser. The laser is compact and reliable, and has low intensity and frequency noise.
Open Access
10W Nd:YAG Laser for TAMA300
(2005) Hosken, D.; Mudge, D.; Veitch, P.; Munch, J.; Takeno, K.; Edoardo Amaldi Conference on Gravitational Waves (6th : 2005: Okinawa, Japan)
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14th Australasian Fluid Mechanics Conference - Preface
(Elsevier Science Inc, 2003) Dally, B.; Kelso, R.; Nathan, G.; Denier, J.
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2,3,7,8,12,13-Hexahydroxy-10,15-dihydro-5H-tribenzo[a,d,g]cyclononene acetone disolvate
(Blackwell Munksgaard, 2007) Sumby, C.; Hardie, M.
The title compound, C21H18O6·2C3H6O, crystallizes as a clathrate complex that includes two acetone guest molecules in a capsular assembly formed by two 2,3,7,8,12,13-hexahydroxy-10,15-dihydro-5H-tribenzo[a,d,g]cyclononene molecules. Intermolecular hydrogen-bonding and host-guest interactions define this dimeric clathrate complex, which is also part of a two-dimensional extensively hydrogen-bonded sheet involving the clathrate complex and acetone solvent molecules in the extended crystal packing.
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2-D Coordination Polymers of Hexa(4-cyanophenyl)[3]-radialene and Silver(I): Anion•••π-Interactions and Radialene C−H•••Anion Hydrogen Bonds in the Solid-State Interactions of Hexaaryl[3]-radialenes with Anions
(American Chemical Society, 2009) Hollis, C.; Hanton, L.; Morris, J.; Sumby, C.
As part of our studies of ligands containing an electron-deficient [3]-radialene core we discovered that the hexadentate ligand hexa(4-cyanophenyl)[3]-radialene 1 forms 6,3-connected 2-D coordination polymers on reaction with silver(I). Compounds {[Ag(1)](PF6) · 2(CH3NO2)}n 2 and {[Ag(1)](ClO4) · 2(CH3NO2)}n 3, which are the first coordination polymers of 1, readily crystallize from solutions of the silver salt and 1 in noncoordinating nitromethane solvent and were characterized by X-ray crystallography. In these structures the ligand is hypodentate, coordinating only through four nitrile N-donors to act as a 3-connecting center. The distorted tetrahedral silver also acts as a 3-connecting center. In the extended structure the anions lie in pockets above and below the [3]-radialene core of the ligands, forming moderate and weak hydrogen bonds with four different molecules of 1. The anions are in close proximity to the electron-deficient [3]-radialene core of 1, forming weak anion-π interactions.
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2005 winter monitoring of the southern Coorong
(Department of Water, Land and Biodiversity Conservation, 2005) Paton, David Cleland; School of Earth and Environmental Sciences
Open Access
3D-visualization and analysis of macro- and meso-porosity of the upper horizons of a sodic, texture-contrast soil
(Blackwell Publishing Ltd, 2007) Jassogne, L.; McNeill, A.; Chittleborough, D.
The lower E and upper B horizons of sodic, texture-contrast soils are a formidable barrier to most annual and many perennial crops. The research presented here is part of a wider study into the nature of subsoil constraints to root exploration. The aim of this study was to characterize in three dimensions the macro- and meso-porosity across the E horizon–Btn horizon interface of a sodic, texture-contrast soil using X-ray computed tomography (CT). Intact soil cores of 50-cm length and 15-cm diameter were scanned with a medical CT X-ray machine. The pore volume reconstructed from these scans had a resolution of 0.3 × 0.3 × 0.4 cm (in the x, y, z dimensions, respectively). This resolution allowed visualization and quantification of the macroporosity of the intact cores. Undisturbed samples of 1.5-cm diameter and 4-cm length were carefully excised from the interface and scanned with micro-CT X-ray equipment. The reconstructed pore volumes had an isotropic resolution of 19 μm that allowed analysis of the mesoporosity just on the boundary between the E and Btn horizons. Mesoporosity decreased across the interface and increased lower in the Btn horizon. The distribution of the pores at the macro- and meso-scales showed the importance of the smaller pores in the A and E horizons, whereas most of the porosity in the Btn horizon was attributed to the larger pores. Pores in this sodic, texture-contrast soil were not distributed homogeneously at either the macro- or meso-scale. A greater proportion of the pores in the E–B interface were horizontal than in the upper A1, upper E and lower Btn horizons. Some ‘coiling’ of the pores was also apparent in the interface. The shape of some pores (long tubular pores) suggested formation by roots as they drilled through the soil. The orientation of these pores was a function of physical (and possibly chemical) impedance at the interface.
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4+1>3+2?
(AAEE, 2009) Kestell, C.; Arjomandi, M.; Dally, B.; Grainger, S.; Blazewicz, A.; Australasian Association for Engineering Education Conference (20th : 2009 : Adelaide, South Australia)
The focus of engineering education has dramatically changed in Europe as a direct result of the Bologna process. While the intention of this was to create a more uniform educational system, another outcome has been that professional engineers are now expected to graduate with a Masters Degree rather than a Bachelors Degree. The University of Melbourne has been the first Australian university to proactively approach this issue by introducing the Melbourne Model, which comprises of a three (not four!) year Bachelors Degree (not a BEng!) followed by a two year Masters Degree (3+2). In an environment conditioned to focus on the quality of undergraduate programs, one initial reaction might be that the degree has been watered down. However, this is far from the case because the emphasis is clearly on the students completing five years of study in total. Melbourne University has in fact raised the bar. Never-the-less, their decision to proceed along this pathway has been perceived as risky and expensive, with few Australian universities following as a result. However, there is a real need to refocus on Masters Programs if our graduating students are to be formally recognised globally as world leaders in their professional capacity. The Faculty of Engineering Computing and Mathematical Sciences (ECMS) at the University of Adelaide will therefore introduce an alternative pathway to Masters in 2010, requiring only one additional year of study upon the successful completion of a four-year Bachelor of Engineering degree. This paper is very much a show and tell work in progress, with only very early indicators of the program’s potential success. While it is believed that there are a number of advantages to the Adelaide Four plus One Model, these are not presented as a better option, but simply as an option. Four plus one programs may be perceived as a long-term solution, or even a transitional solution towards a three plus two. Regardless of the preferred pathway, Australian Universities must now prepare for the obviously imminent refocusing of our educational system towards Masters Programs.
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A 'Collins' monster'-type lobopodian from the Emu Bay Shale Konservat-Lagerstätte (Cambrian), South Australia
(Geological Society Australia Inc, 2013) Garcia-Bellido, D.; Edgecombe, G.; Paterson, J.; Ma, X.
A distinctive group of lobopodians known from Cambrian Stage 5 in western Laurentia includes Acinocricus Conway Morris & Robison, 1988, from the Spence Shale in Utah, and an unnamed species from the Burgess Shale, British Columbia, popularly known as ‘Collins’ monster’. The temporal gap from their closest relative, the Chengjiang lobopodian Luolishania, is bridged by a single, incomplete specimen of a Collins’ monster-type lobopodian from the Emu Bay Shale (Cambrian Series 2, Stage 4), Kangaroo Island, South Australia, the first lobopodian discovered in this Konservat-Lagerstätte. Pending formal description of the Burgess Shale species, the Australian specimen is left unassigned to a genus.
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A 1 GHz differential 2nd-order lowpass sigma delta modulator in CMOS for wireless receivers
(SPIE, 2004) Zhu, Y.; Al-Sarawi, S.; Liebelt, M.; Microelectronics, MEMS, and Nanotechnology (2003 : Perth, Australia); Abbott, D.; Eshraghian, K.; Musca, C.; Pavlidis, D.; Weste, N.
This paper presents the design of a 1 GHz continuous-time second order Lowpass Sigma Delta Modulator (LPSDM). The design is intended to meet the future requirements of wideband wireless receivers. The continuous-time Noise Transfer Function (NTF) for the modulator is realized using two Gm-C integrators with negative transconductance feedback and three linearized Gm elements. A three-stage delayed comparator is employed for designing the one bit quantizer, therefore a delayed NTF had to be synthesized. The presented target design is 0.18µm CMOS process. The designed chip uses both 3.3V and 1.8V MOSFETs and consumes 80mW including the clock driver and the output buffer. The performance of the modulator based on post layout simulation is 11 bits for a 5 MHz bandwidth and 8.6 bits for an 11MHz bandwidth.
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A 1.4-Mb interval RH map of horse chromosome 17 provides detailed comparison with human and mouse homologues
(Academic Press Inc Elsevier Science, 2004) Lee, E.; Raudsepp, T.; Kata, S.; Adelson, D.; Womack, J.; Skow, L.; Chowdhary, B.
Comparative genomics has served as a backbone for the rapid development of gene maps in domesticated animals. The integration of this approach with radiation hybrid (RH) analysis provides one of the most direct ways to obtain physically ordered comparative maps across evolutionarily diverged species. We herein report the development of a detailed RH and comparative map for horse chromosome 17 (ECA17). With markers distributed at an average interval of every 1.4 Mb, the map is currently the most informative among the equine chromosomes. It comprises 75 markers (56 genes and 19 microsatellites), of which 50 gene specific and 5 microsatellite markers were generated in this study and typed to our 5000-rad horse × hamster whole genome RH panel. The markers are dispersed over six RH linkage groups and span 825 cR₅₀₀₀. The map is among the most comprehensive whole chromosome comparative maps currently available for domesticated animals. It finely aligns ECA17 to human and mouse homologues (HSA13 and MMU1, 3, 5, 8, and 14, respectively) and homologues in other domesticated animals. Comparisons provide insight into their relative organization and help to identify evolutionarily conserved segments. The new ECA17 map will serve as a template for the development of clusters of BAC contigs in regions containing genes of interest. Sequencing of these regions will help to initiate studies aimed at understanding the molecular mechanisms for various diseases and inherited disorders in horse as well as human.
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A 100W, double-clad, Nd:YAG slab laser
(2006) Mudge, D.; Hosken, D.; Veitch, P.; Munch, J.; Australian Institute of Physics Congress (17th : 2006 : Brisbane, Australia)
Lasers that produce high average power, single longitudinal mode, diffraction-limited output are required for a variety of high precision remote sensing applications. For example, advanced interferometric gravitational wave detectors require ultra-stable 100W-class, single frequency CW Nd:YAG lasers with diffraction-limited output. Lasers for Na lidar and coherent laser radar systems must, in addition, be capable of high peak power, typically 10 mJ in 10-100 ns and produce transform limited pulses. We shall describe a novel end-pumped, side-cooled, double-clad composite slab architecture that is suitable for these high power applications, and which can be injection-locked or injection-seeded to obtain spectral control. The composite structure and end-pumping allow the use of low brightness pump sources and optimizes the gain distribution while minimizing thermal lensing and thermally induced birefringence. The slab supports a folded zigzag laser mode and is side-cooled, with the top and bottom edges temperature controlled. The side-cooling enables power scaling and is achieved without any direct water contact, enhancing reliability. An output power of 103 W using a pump power of 280 W has been achieved, with a slope efficiency of 44%. Interferometric measurements show that the thermal lens is weak, with a focal length of approximately 25 cm at this pump power, and can be changed by adjusting the boundary conditions. We shall report latest results of power scaling and beam quality measurements.
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A 10W cw Nd:YAG laser for gravitational wave interferometry
(2003) Hosken, D.; Mudge, D.; Veitch, P.; Munch, J.; Takeno, K.; Australasian Conference on Optics, Lasers and Spectroscopy (2003 : Melbourne, Australia)
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A 2.5-Mb contig constructed from Angus Longhorn and horned Hereford DNA spanning the polled interval on bovine chromosome 1
(Blackwell Publishing Ltd, 2006) Wunderlich, K.; Abbey, C.; Clayton, D.; Song, Y.; Schein, J.; Georges, M.; Coppieters, W.; Adelson, D.; Taylor, J.; Davis, S.; Gill, C.
The polled locus has been mapped by genetic linkage analysis to the proximal region of bovine chromosome 1. As an intermediate step in our efforts to identify the polled locus and the underlying causative mutation for the polled phenotype, we have constructed a BACbased physical map of the interval containing the polled locus. Clones containing genes and markers in the critical interval were isolated from the TAMBT (constructed from Angus and Longhorn genomic DNA) and CHORI-240 (constructed from horned Hereford genomic DNA) BAC libraries and ordered based on fingerprinting and the presence or absence of 80 STS markers. A single contig spanning 2.5 Mb was assembled. Comparison of the physical order of STSs to the corresponding region of human chromosome 21 revealed the same order of genes within the polled critical interval. This contig of overlapping BAC clones from horned and polled breeds is a useful resource for SNP discovery and characterization of positional candidate genes.
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A 3D lithospheric electrical resistivity model of the Gawler Craton, Southern Australia
(Inst Mining Metallurgy, 2007) Maier, R.; Heinson, G.; Thiel, S.; Selway, K.; Gill, R.; Scroggs, M.
A three-dimensional lithospheric electrical resistivity model of the Archaean-Proterozoic Gawler Craton in southern Australia has been developed, to define the tectonic framework of the craton and identify craton margins under regolith cover. Knowledge of cratonic margins is important as upwards of 60% of known mineral wealth is located in palaeoconvergent zones between ancient cratons. The research was conducted in three phases. First, all previous magnetotelluric (MT) and geomagnetic depth sounding (GDS) data were compiled to establish a regional scale induction database. Almost 400 observation sites were found in the literature and from personal communication, collected over the last 30 years by various research groups. Of these, most measurements were GDS only, but recent 2D MT sites along major profiles provide further depth constraints. Second, eight long period MT sites were collected from central areas of the craton to provide a window into the deeper lithosphere and asthenosphere. Data were collected over a number of weeks to establish high quality MT responses in the bandwidth 10-10⁴ s. One-dimensional modelling indicated that the lithosphere was resistive (>100 Ω m), with a more conductive midmantle at 70 km and a decrease in resistivity at the transition zone. These MIT responses agree with the long period (10⁴-10⁷ s) continental lithosphere induction responses of Olsen (N. Olsen: 'Long-period (30 days-1 year) electromagnetic sounding and the electrical conductivity of the lower mantle beneath Europe', Geophys. J. Int., 1999, 138, 179-187). Finally, a 3D resistivity model of the lithosphere was compiled from 2D inversions of MT profiles, with constraints from lithosphere asthenosphere soundings, and regional scale GDS data. The Gawler Craton is shown to have a resistive core of dimension 500 km, surrounded by more conductive terrains. The core is largely, but not exclusively, Archaean crust, surrounded by conductive Proterozoic crust. The edge of the core on the eastern side of the Gawler Craton correlates with the location of several iron oxide-copper-gold deposits, including the world class Olympic Dam deposit, potentially making mapping of large scale resistivity structures a useful tool for regional scale exploration. © 2007 Institute of Materials, Minerals and Mining and The AusIMM.
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A baseline study for on-line condition monitoring of induction machines
(AUPEC 2004, 2004) Ahmed, I.; Supangat, R.; Grieger, J.; Ertugrul, N.; Soong, W.; Australasian Universities Power Engineering Conference (14th : 2004 : Brisbane, Australia); Saha, T.
Condition monitoring of induction machines relies on being able to detect the difference between healthy and faulty induction machines. An accurate interpretation of a motor’s condition requires knowledge of the effects of different operating conditions. In addition, variability between machines and test repeatability has to be considered. This paper investigates the above effects on the characteristic induction motor fault frequencies using results from an extensive series of tests on a number of identical healthy machines, which accommodates non-invasive measurements of axial flux, vibration, current and voltage of the motors under test. This work represents the baseline comparison stage of a future investigation into on-line multiple sensor type condition monitoring of induction machines, which aims is to set threshold levels for fault detection including level of loading and nonideal supplies.
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A Bayesian approach to artificial neural network model selection
(Modelling and Simulation Society of Australia and New Zealand Inc., 2005) Humphrey, G.; Maier, H.; Lambert, M.; International Congress on Modelling and Simulation (16th : 2005 : Melbourne, Victoria); Zerger, A.; Argent, R.
Artificial neural networks (ANNs) have proven to be extremely valuable tools in the field of water resources engineering. However, one of the most difficult tasks in developing an ANN is determining the optimum level of complexity required to model a given problem, as there is no formal systematic model selection method. The generalisability of an ANN, which is defined by its predictive performance on the universe of possible data, can be significantly impaired if there are too few or too many hidden nodes in the network. Therefore, for an ANN to be a valuable prediction tool, it is important that some effort is made to optimise the number of hidden nodes. This paper presents a Bayesian model selection (BMS) method for ANNs that provides an objective approach for comparing models of varying complexity in order to select the most appropriate ANN structure. Given a set of competing models ℋ1, . . . ,ℋH, BMS is used to compare the posterior probability that each model ℋi is the true data generating function, given a set of observed data y. This probability is also known as the evidence of a model and the ratio of two competing models' evidence values, known as the Bayes' factor, can be used to rank the competing models in terms of the relative evidence in support of each model. For ANNs (and other complex models), the evidence of a model p(ℋ|y) is analytically intractable and, consequently, alternative methods are required to estimate these probabilities for the competing models. One such method involves the use of Markov chain Monte Carlo (MCMC) simulations from the posterior weight distribution p(w|y, ℋ) to approximate the evidence. It has already been shown that there are numerous benefits to estimating the posterior distribution of ANN weights with MCMC methods; therefore, the proposed BMS approach is based on such an approximation of p(y|ℋ), as this only requires a simple additional step after sampling from p(w|y, ℋ). Furthermore, the weight distributions obtained from the MCMC simulation provide a useful check of the accuracy to the approximated Bayes' factors. A problem associated with the use of posterior simulations to estimate a model's evidence is that the approximation may be sensitive to factors associated with the MCMC simulation. Therefore, the proposed BMS method for ANNs incorporates a further check of the accuracy of the computed Bayes' factors by inspecting the marginal posterior distributions of the hidden-to-output layer weights, which indicate whether all of the hidden nodes in the model are necessary. The fact that this check is available is one of the greatest advantages of the proposed approach over conventional model selection methods, which do not provide such a test and instead rely on the modeller's subjective choice of selection criterion. The aim of model selection is to enable generalisation to new cases. Therefore, in the case study presented in this paper, the performance of the proposed BMS method was assessed in comparison to the performance of conventional ANN selection methods on data outside the domain of the training data. This case study, which involves forecasting salinity concentrations in the River Murray at Murray Bridge, South Australia, 14 days in advance, was chosen as it had been shown previously that, if an ANN was trained on the first half of the available data, it would be required to extrapolate in some cases when applied to the second half of the available data set. In this case study, the proposed BMS framework for ANNs was shown to be more successful than conventional model selection methods in selecting an ANN that could approximate the relationship contained in the training data and generalise to new cases outside the domain of those used for training. The Bayes' factors calculated were useful for obtaining an initial guide to the most appropriate model; however, the final step involving inspection of marginal posterior hidden-tooutput weight distributions was necessary for the final selection of the optimum number of hidden nodes. The model selected using the proposed BMS approach not only had the best generalisability, but was also more parsimonious than the models selected using conventional methods and required considerably less time for training.
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A Bayesian method to improve the extrapolation ability of ANNs
(ACTA Press, 2005) Humphrey, G.; Maier, H.; Lambert, M.; International Conference on Applied Simulation and Modelling (14th : 2005 : Benalmadena, Spain); Hamza, M.
Although artiﬁcial neural networks have been shown to be superior prediction models in many hydrology-related areas, their known lack of extrapolation capability has limited the wider use and acceptance of ANNs as forecasting models. This problem lies mainly with the fact that a single 'most likely' weight vector, which is determined by calibration with a ﬁnite set of data, is used to deﬁne the function modelled by the ANN. There are, in fact, many different weight vectors that result in approximately equal model performance; however, standard ANN development approaches do not allow for any weight vectors, other than that which provides the best ﬁt to the calibration data, to impact on the predictions made. In this paper, a Bayesian method is presented that enables the entire range of plausible weight vectors to be accounted for in the model predictions. In doing so, the relationship modelled by the ANN is more general and less dominated by the information contained in the calibration data. The method is applied to a real-world case study known to require extrapolation and the resulting ANN is shown to perform signiﬁcantly better than an ANN developed using standard approaches.
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A behavioural approach for household outdoor water use modelling
(Engineers Australia, 2011) Micevski, T.; Thyer, M.; Kuczera, G.; IAHR World Congress (34th : 2011 : Brisbane, Australia)
Reliable predictions of household outdoor water use are important inputs for effective design and management of urban water systems. This paper evaluates and enhances the behavioural approach (BA) for modelling outdoor water use. The underlying premise in the BA is that outdoor water use is governed by people's probabilistic behavioural response to recent weather conditions (rainfall and temperature).The BA models used in this paper were evaluated using a 12 year dataset of monthly outdoor water use for 135 homes in the Newcastle region of New South Wales, Australia. The BA model of Coombes et al (2000) was found to found to outperform traditional linear regression techniques, after calibration using a new simulated likelihood calibration approach. However, it was found to be over-parameterised and underestimated observed variability by 22%. An enhanced BA model was more parsimonious and better simulated the observed variability (only 9% underestimation). Conditioning behavioural response on daily rainfall and maximum temperature did not provide good model performance. Rather, the major drivers of household outdoor water use variability were found to be long dry periods (for 80% of homes), while a smaller number (20%) additionally responded to the long hot periods (characterised by the degree day concept).

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