Engineering Commons^™

A Multi-Staged Management Strategy For Restoring Tidal Flushing, William Glamore, Buddhima Indraratna

Faculty of Engineering - Papers (Archive)

Tidal restoration/wetland rehabilitation projects are being undertallimitations, this paper presents a tidal restoration/floodgate manipulation strategy that was developed from a four-year field study undertaken in southeastern NSW and subsequently applied at multiple field sites. An eight stage methodology is proposed to incorporate water quality, hydraulics, groundwater/saline intrusion, hydrology, field monitoring and flood design criteria. The strategy begins with a quantification of perceived outcomes for the study. Using these goals, the potential improvement in water quality are calculated using ion association models and field sampling techniques. The third stage quantifies the spatial flooding extent using GIS spatial analysis methods. The risks …

Hand Gesture Selection And Recognition For Visual-Based Human-Machine Interface, Abdolah Chalechale, Farzad Safaei, Golshah Naghdy, Prashan Premaratne

Faculty of Engineering - Papers (Archive)

A new paradigm has been proposed for gesture selection and recognition. The paradigm is based on statistical classification, which has applications in telemedicine, virtual reality, computer games, and sign language studies. The aims of this paper are (1) how to select an appropriate set of gestures having a satisfactory level of discrimination power, and (2) comparison of invariant moments (conventional and Zernike) and geometric properties in recognizing hand gestures. Two-dimensional structures, namely cluster-property and cluster-features matrices, have been employed for gesture selection and to evaluate different gesture characteristics. Moment invariants, Zernike moments, and geometric features are employed for classification and …

Design Of A Light Chamber For The Characterisation Of Flicker Behaviour Of Lamps, John Braun, Sarath Perera, Vic Gosbell

Faculty of Engineering - Papers (Archive)

This paper presents the design of a light chamber which can be used to investigate the flicker behaviour of various types of lamps. Using this system, a lamp can be subjected to a controlled voltage waveform while current and illuminance of the lamp are monitored. With the aid of such a voltage source capable of generating voltage fluctuations, including interharmonics and other power quality disturbances, the relationship between waveform and light flux fluctuation can be modelled. Such a system can be easily built with off the shelf equipment, but the cost would be prohibitive. To circumvent this problem, the design …

A Flexible Time-Varying Generalised Minimum Variance Controller, Zheng Li, Christian Schmid

Faculty of Engineering - Papers (Archive)

The problem of generalised minimum variance control of linear time-varying systems is studied in this paper. A generalised minimum variance controller is developed in a transfer operator framework for linear time-varying systems using a pseduocommutation technique and a more flexible cost functional that includes time-varying filters for the plant input and output.

Hand Posture Analysis For Visual-Based Human-Machine Interface, Abdoleh Chalechale, Farzad Safaei, Golshah Naghdy, Prashan Premaratne

Faculty of Engineering - Papers (Archive)

This paper presents a new scheme for hand posture selection and recognition based on statistical classification. It has applications in telemedicine, virtual reality, computer games, and sign language studies. The focus is placed on (1) how to select an appropriate set of postures having a satisfactory level of discrimination power, and (2) comparison of geometric and moment invariant properties to recognize hand postures. We have introduced cluster-property and cluster-features matrices to ease posture selection and to evaluate different posture characteristics. Simple and fast decision functions are derived for classification, which expedite on-line decision making process. Experimental results confirm the efficacy …

Unresolved Problems In Power Quality, Victor Gosbell

Faculty of Engineering - Papers (Archive)

The Power Quality Centre at the University of Wollongong has been in operation since 1996 and has made progress in many areas of power quality, with power system harmonics being a major focus. The paper will discuss some important issues in harmonics still needing to be resolved, including (i) the economic case for harmonic control, (ii) the setting of appropriate voltage limits, (iii) measurement of time-varying harmonics, (iv) the modelling of distorting loads, (v) allocation of harmonic current and (vi) the identification of harmonic offenders. There is brief mention of other important power quality issues still needing to be addressed.

Evaluation Of Gradient Control Wire And Insulating Joints As Methods Of Mitigating Induced Voltages In Gas Pipelines, Dejan Markovic, V. Smith, Sarath Perera

Faculty of Engineering - Papers (Archive)

Significant voltage levels can be induced in the gas pipelines due to power transmission lines in the areas where they share the same corridor, especially during a fault. These voltages can affect the operating personnel, pipeline associated equipment, cathodic protection and the pipeline itself. Quite often, mitigation is required to reduce these induced voltages to levels that are safe for personnel and integrity of the pipeline. This paper compares features of two mitigation methods: insulating joints and gradient control wire. An existing Agility pipeline is modelled using the specialized CDEGS software incorporating these two mitigation methods in order to compare …

A Generalised Minimum Variance Controller For Time-Varying Systems, Z. Li, Christian Schmid

Faculty of Engineering - Papers (Archive)

In this paper, the problem of generalised minimum variance control of linear time-varying systems is studied. A time-varying optimal controller is developed for a standard controlled autoregressive moving average model using a cost function that is the sum of the plant output tracking error variance plus a penalty term of the squared manipulated variable.

A Time-Varying Generalised Minimum Variance Controller, Z. Li, Christian Schmid

Faculty of Engineering - Papers (Archive)

A generalized minimum variance controller is developed for linear time-varying systems. The plants to be controlled are described using a controlled auto-regressive moving average model and are exponentially stable. Both, the plant parameters and the noise variance are time-varying. The generalized minimum variance cost functional is the sum of a tracking error variance between a filtered plant output and a filtered reference plus a penalty term of filtered plant input. Time-varying filters are introduced for weighting to make the controller more flexible.

Revival Of Superconductivity By Y3+/Ca2+ Substitution In Yba2cu2.7co0.3o7 Without Reported Phase Transformation, M. Ansari, Rashmi Nigam, V. Awana, Anurag Gupta, Ravindra Saxena, H. Kishan, N. Lalla, V. Ganesan, Anant Narlikar, C. Cardoso

Faculty of Engineering - Papers (Archive)

Results of phase formation, resistivity (r), and thermo-electric power (S), are reported on Y1-xCaxBa2Cu2.7Co0.3O7 compounds with x = 0.1 and 0.2. Pristine compound i.e. without Co or Ca substitution crystallizes in orthorhombic structure with space group P/mmm. Cu-site Co substituted compound i.e. YBa2Cu2.7Co0.3O7 is tetragonal. With simultaneous doping of Ca at Y site in Co substituted compound i.e. Y1-xCaxBa2Cu2.7Co0.3O7 the tetragonal nature still remains. r(T) measurements showed superconducting transition temperature (Tc) to decrease from 90K (YBa2Cu3O7) to 33 K for YBa2Cu2.7Co0.3O7 which with further Ca substitution increases from 33K to 53K (Y0.9 Ca0.1Ba2Cu2.7Co0.3O7) and 67 K for Y0.8 Ca0.2Ba2Cu2.7Co0.3O7. Tc …

Scalable Multi-Resolution Color Image Segmentation, Fardin Akhlaghian Tab, Golshah Naghdy, A. Mertins

Faculty of Engineering - Papers (Archive)

This paper presents a novel multiresolution image segmentation method based on the discrete wavelet transform and Markov Random Field (MRF) modelling. A major contribution of this work is to add spatial scalability to the segmentation algorithm producing the same segmentation pattern at different resolutions. This property makes it applicable for scalable object-based wavelet coding. To optimize segmentation at all resolutions of the wavelet pyramid, with scalability constraint, a multiresolution analysis is incorporated into the objective function of the MRF segmentation algorithm. Examining the corresponding pixels at different resolutions simultaneously enables the algorithm to directly segment the images in the YUV …

A Study On The Charge-Discharge Mechanism Of Co3o4 As An Anode For The Li Ion Secondary Battery, Yong-Mook Kang, Min-Sang Song, Jin-Ho Kim, Hyun-Seok Kim, Min-Sik Park, Jai-Young Lee, Hua-Kun Liu, S X. Dou

Australian Institute for Innovative Materials - Papers

Co₃O₄ has shown acceptable electrochemical properties as the anode material of Li secondary batteries. In detail, its capacity reached about 700 mAh/g, twice as high as graphite, and 93.4% of initial capacity was retained after 100 cycles. EIS (electrochemical impedance spectroscopy) analyses revealed that after the 1st cycle, the insertion or extraction of Li ions in Co₃O₄ can occur homogeneously and reversibly (randless-like behavior, homogeneous mixture: Co + Li₂O (in the state of Li insertion), Co₃O₄ (in the state of Li extraction)). In fact, the coulombic efficiency of Co …

A New Magnetoplasmon Sound Wave In A Two-Dimensional Electron Gas Under Electromagnetic Radiation, C Zhang, S Hessami Pilehrood

Australian Institute for Innovative Materials - Papers

We report a new magnetoplasmon mode and a sound-like collective excitation in two-dimensional electronic systems under a weak magnetic field and a low-frequency electromagnetic radiation. The analysis is based on the exact time-dependent wave functions and the exact relation between response function with and without radiation. The new mode discovered here can be used as a generating mechanism of high-frequency radiation from a system whose characteristic energy is low.

Magnetic And Transport Properties Of The Layered Perovskite System Sr2-Yyycoo4 (0< Y < 1), Xiaolin Wang, E Takayama-Muromachi

Australian Institute for Innovative Materials - Papers

Layered perovskite cobalt oxides Sr2-yYyCoO4 (y=0, 0.1, 0.3, 0.5, 0.67, 0.83 and 1) were synthesized under high pressure and high temperature conditions.

Nano-Structured Sno2-Carbon Composites Obtained By In Situ Spray Pyrolysis Method As Anodes In Lithium Batteries, Ling Yuan, Konstantin Konstantinov, Guoxiu Wang, Hua-Kun Liu, S X. Dou

Australian Institute for Innovative Materials - Papers

In this paper, we report on a series of SnO₂-carbon nano-composites synthesized by in situ spray pyrolysis of a solution of SnCl₂·2H₂O and sucrose at 700 °C. The process results in super fine nanocrystalline SnO₂, which is homogeneously distributed inside the amorphous carbon matrix. The SnO₂ was revealed as a structure of broken hollow spheres with porosity on both the inside and outside particle surfaces. This structure promises a highly developed specific surface area. X-ray diffraction (XRD) patterns and transmission electron microscope (TEM) images revealed the SnO₂ crystal size is …

Magnetic Ordering And Spin Waves In Na0.82coo2, S P. Bayrakci, I Mirebeau, P Bourges, Y Sidis, M Enderle, J Mesot, Dapeng Chen, C T Lin, B Keimer

Australian Institute for Innovative Materials - Papers

NaxCoO2, the parent compound of the recently synthesized superconductor NaxCoO2∶yH2O, exhibits bulk antiferromagnetic order below ∼20   K for 0.75≤x≤0.9. We have performed neutron scattering experiments in which we observed Bragg reflections corresponding to A-type antiferromagnetic order in a Na0.82CoO2 single crystal and characterized the corresponding spin-wave dispersions. The spin waves exhibit a strongly energy-dependent linewidth. The in-plane and out-of-plane exchange constants resulting from a fit to a nearest-neighbor Heisenberg model are similar in magnitude, which is unexpected in view of the layered crystal structure of NaxCoO2. Possible implications of these observations are discussed.

Nonmagnetic Insulator State In Na1coo2 And Phase Separation Of Na Vacancies, C De Vaulx, M. -H Julien, C Berthier, M Horvatic, P Bordet, V Simonet, Dapeng Chen, C T. Lin

Australian Institute for Innovative Materials - Papers

Crystallographic, magnetic, and NMR properties of a NaxCoO2 single crystal with x≃1 are presented. We identify the stoichiometric Na1CoO2 phase, which is shown to be a nonmagnetic insulator, as expected for homogeneous planes of Co3+ ions with S=0. In addition, we present evidence that, because of slight average Na deficiency, chemical and electronic phase separation leads to a segregation of Na vacancies into the well-defined, magnetic, Na0.8CoO2 phase. The importance of phase separation is discussed in the context of magnetic order for x≃0.8 and the occurrence of a metal-insulator transition for x→1.

Atomic Layer Depostion Of Tio2/Al2o3 Films For Optical Applications, G Triani, P J. Evans, D Rg Mitchell, D J. Attard, K Finnie, M James, T Hanley, B Latella, Kathryn Prince, J Bartlett

Australian Institute for Innovative Materials - Papers

Atomic layer deposition (ALD) is an important technology for depositing functional coatings on accessible, reactive surfaces with precise control of thickness and nanostructure. Unlike conventional chemical vapour deposition, where growth rate is dependent on reactant flux, ALD employs sequential surface chemical reactions to saturate a surface with a (sub-) monolayer of reactive compounds such as metal alkoxides or covalent halides, followed by reaction with a second compound such as water to deposit coatings layer-by-layer. A judicious choice of reactants and processing conditions ensures that the reactions are self-limiting, resulting in controlled film growth with excellent conformality to the substrate.

This …

1-(4-Chlorophenyl)-2-Methyl-4-Nitro-5-(1-Piperidyl)-1h-Imidazole, Maciej Kubicki, Pawel Wagner

Australian Institute for Innovative Materials - Papers

The only specific interactions that influence the crystal packing of the title compound, C15H17ClN4O2, are weak C-H...N and C-H...Cl hydrogen bonds, even though there is a possibility of, for example, pi-pi stacking or halogen bonding. The dihedral angle between the mean planes of the imidazole and benzene rings is 59.82 (5) degrees . The length of the C-N bond connecting the imidazole and piperidine fragments is correlated with the degree of pyramidalization of the piperidine N atom.

Double Injection As A Technique To Study Charge Carrier Transport And Recombination In Bulk-Heterojunction Solar-Cells, G Juska, K Arlauskas, G Sliauzys, A Pivrikas, Attila Mozer, Serdar Sariciftci, Markus Scharber, R Osterbacka

Australian Institute for Innovative Materials - Papers

Ambipolar charge carriermobility and recombination in bulk-heterojunction solar cells based on the mixture of regioregular poly(3-hexylthiophene) and 1-(3-methoxycarbonyl)propyl-1-phenyl-[6,6]-methanofullerene (PCBM) has been studied using injection current transients. The experimental results demonstrate double injection with bimolecular recombination limiting the injection current. We found that charge carrier bimolecular recombination is significantly reduced compared to Langevin recombination. We have measured the temperature and electric field dependence of the reduced bimolecular recombination coefficient and the results suggest that the electron and hole pathways are different and the recombination is controlled by the probability of the carriers to meet at the polymer/PCBM interface.

The Effects Of Oil Concentration And Droplet Diameter In Oil-In-Water Emulsion On Strip Rolling, Prabuono B. Kosasih, A. K. Tieu, Weihua Li, Cheng Lu

Faculty of Engineering - Papers (Archive)

A numerical scheme, which allows tracking of the concentration process within both the inlet and wok zones, has been developed. The scheme allowed us to calculate the rolling pressure and friction associated with the process for different emulsion’s oil concentrations, and oil droplets diameter, ds. Hence the intertwined effect of A,ds, ds and rolling speed on strip rolling parameters could be analyzed. The result shows that rapid concentration, which occurs in the inlet zone, increases the emulsion’s oil concentration sharply. This process effectively transforms the oil into the continuous phase of the emulsion. The analysis of the results also suggests …

Micromechanics Of Thin Oxide Scale And Surface Roughness Transfer In Hot Metal Rolling, Zhengyi Jiang, Weihua Sun, Jianning Tang, Dongbin Wei, A. K. Tieu

Faculty of Engineering - Papers (Archive)

The deformation micromechanics of the thin oxide scale formed in hot metal rolling and surface roughness transfer characterization are very important for the quality of the finished product. Finite element simulation of the thin oxide scale deformation and surface roughness transfer is carried out. Surface asperity deformation of the thin oxide scale and strip is focused. Surface characterisation and micromechanics of the thin oxide scale deformation are obtained from the finite element simulation and experimental measurements. Simulation results are close to the measured values. The forming features of surface roughness transfer during hot metal rolling with lubrication are also discussed.

Evaluation Of Control Techniques For Dip Transfer Gas Metal Arc Welding, Gary Dean, John Norrish, Christopher D. Cook

Faculty of Engineering - Papers (Archive)

Dip transfer gas metal arc welding (GMAW) is used extensively for high productivity welding of thin sheet steel, and is also useful for positional welding of thicker section steels. Unfortunately in the past, the process has gained a reputation for fusion defects, which becomes more apparent when welding traditionally difficult materials such as coated steels. This reputation can be attributed in some instances to the method of control used and the changeable nature of variables crucial to controlling heat transfer during the welding process. The paper examines the relationship between weld fusion, heat input and current for coated steel welding …

A Deformable Model With Cellular Neural Network, Yongmin Zhong, Bijan Shirinzadeh, Gursel Alici, Julian Smith

Faculty of Engineering - Papers (Archive)

This paper presents a new methodology for deformable models by drawing an analogy between cellular neural network (CNN) and elastic deformation. The potential energy stored in an elastic body as a result of a deformation caused by an external force is propagated among mass points by the local connectivity of cells and the CNN dynamics. An improved CNN model is developed for propagating the energy generated by the external force on the object surface. A method is presented to derive the internal forces from the potential energy distribution established by the CNN. The methodology proposed in this paper can not …

The Use Of Embedded Sensors For The Monitoring Of Adhesive Joints In Marine Environments, Scott T. Mcgovern, Geoffrey M. Spinks, G G. Wallace

Faculty of Engineering - Papers (Archive)

A copolymer incorporating polyaniline was used as a sensing medium in the construction of a resistance based humidity sensor. Aniline monomer was polymerised in the presence of poly (butyl acrylate / vinyl acetate) and a copolymer containing polyaniline emeraldine salt was obtained. The sensing medium was then developed by redissolving 1-2 w/w% of the resulting polymer residue in dichloromethane to produce a processable polymer blend solution. Some of this polymer residue was also de-doped in a solution of ammonia, and then washed with distilled water until the waste water had a neutral pH. This residue was then redissolved at 1-2 …

The Stability Of Cementite Formed From Hematite And Titanomagnetite Ore Under Carburising Atmosphere, R Longbottom, D Young, J Zhang, O Ostrovski

Faculty of Engineering - Papers (Archive)

The decomposition of cementite formed from hematite and pre-oxidised titanomagnetite was investigated in the temperature range from 500°C to 925°C for hematite, and from 300°C to 1100°C for titanomagnetite under a carburising atmosphere in a fixed bed reactor. For hematite, cementite was most stable at temperatures 7S0-770°C. The decomposition rate increased with decreasing temperature between 7S0°C and 600°C and with increasing temperature above 770°C. For ironsand, cementite was most stable in the temperature range 700-900°C. The rate of decomposition of cementite increased with decreasing temperature between 700°C and 400°C and with increasing temperature above 900°C. Cementite formed from ironsand was …

Characterisation Of Manganese Furnace Dust And Zinc Balance In Production Of Manganese Alloys, Ruihua Shen, Guangqing Zhang, Mark Dell'amico, Peter Brown, Oleg Ostrovski

Faculty of Engineering - Papers (Archive)

No abstract provided.

Multidisciplinary Design In Virtual Worlds, M A. Rosenman, G Smith, L Ding, D Marchant, M L. Maher

Faculty of Engineering - Papers (Archive)

Large design projects, such as those in the AEC domain, involve collaboration among a number of design disciplines, often in separate locations. With the increase in CAD usage in design offices, there has been an increase in the interest in collaboration using the electronic medium, both synchronously and asynchronously. The use of a single shared database representing a single model of a building has been widely put forward but this paper argues that this does not take into account the different representations required by each discipline. This paper puts forward an environment which provides real-time multi-user collaboration in a 3D …

Multi-Objective Evolutionary Algorithm For Investigating The Trade-Off Between Pleiotropy And Redundancy, Zhiyang Ong, Hao-Wei Lo, Matthew J. Berryman, Derek Abbott

Faculty of Engineering - Papers (Archive)

The trade-off between pleiotropy and redundancy in telecommunications networks is analyzed in this paper. They are optimized to reduce installation costs and propagation delays. Pleiotropy of a server in a telecommunications network is defined as the number of clients and servers that it can service whilst redundancy is described as the number of servers servicing a client. Telecommunications networks containing many servers with large pleiotropy are cost-effective but vulnerable to network failures and attacks. Conversely, those networks containing many servers with high redundancy are reliable but costly. Several key issues regarding the choice of cost functions and techniques in evolutionary …

Contagions Across Networks: Colds And Markets, Matthew J. Berryman, Neil F. Johnson, Derek Abbott

Faculty of Engineering - Papers (Archive)

We explore a variety of network models describing transmission across a network. In particular we focus on transmission across composite networks, or “networks of networks”, in which a finite number of networked objects are then themselves connected together into a network. In a disease context we introduce two interrelated viruses to hosts on a network, to model the infection of hosts in a classroom situation, with high rates of infection within a classroom, and lower rates of infection between classrooms. The hosts can be either susceptible to infection, infected, or recovering from each virus. During the infection stage and recovery …