School of Mechanical & Mining Engineering Publications  UQ eSpace
http://espace.library.uq.edu.au/
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Advances in hard rock mining technology
http://espace.library.uq.edu.au/view/UQ:100036
20070823T19:10:57Z
Hood, M.

Advances in Mg corrosion and research suggestions
http://espace.library.uq.edu.au/view/UQ:320988
20140116T15:25:40Z
Atrens, Andrejs; Song, Guangling; Cao, Fuyong; Shi, Zhiming; Bowen, Patrick K.

Advances in the quantification of gold deportment by QemSCAN
http://espace.library.uq.edu.au/view/UQ:148593
20080606T14:40:49Z
Butcher, A. R.; Helms, T.; Gottlieb, P.

Advantages of milling and drilling Ti6Al4V components with highpressure coolant
http://espace.library.uq.edu.au/view/UQ:326067
20140319T14:36:22Z
Bermingham, M. J.; Palanisamy, S.; Morr, D.; Andrews, R.; Dargusch, M. S.

Aeolian tones generated by a square cylinder with a detached flat plate
http://espace.library.uq.edu.au/view/UQ:255688
A possibility of a rigid flat plate that is placed in the wake of a square cylinder for a passive sound control is investigated numerically. The changes in the sound generation with gap distances are inspected at a Reynolds number of 150 and a Mach number of 0.2 for a constant plate length of D. Two regimes that significantly effects the sound generation are identified. The first regime, i.e. prevortex regime, is for 0 G 2.3D and the second regime, i.e. postvortex regime, is for 2.4D G 7D. A sound reduction can be obtained in prevortex regime, where about 2.9 dB sound reduction is obtained when there is no gap between the two bodies. Contrary, at least an increase 8.0 dB sound level is emitted when the plate is placed in the postvortex regime. Despite of that, a 6.3 dB sound reduction is obtained when the plate length is reduced to 0.26D and placed at 5.6D downstream of the cylinder. The sound reduction is limited by the deformation in the sinusoidal signal of the plate due to the unsteady plate stall process.
20111013T16:27:46Z
Ali, Mohamed Sukri Mat Ali; Doolan, Con J.; Wheatley, Vincent

Aeolian tones generated by a square cylinder with a detached flat plate
http://espace.library.uq.edu.au/view/UQ:293273
The case of a rigid flat plate placed in the wake of a square cylinder for passive sound control is investigated numerically at a Reynolds number of 150 and a Mach number of 0.2. Two flow regimes are observed, and these are shown to affect the radiated sound. An overall sound reduction at an observer directly above the cylinder is observed for a small gap distance G between the cylinder and the plate (0 ≤ G ≤ 2.3D, in which D is the cylinder height), where a 2.9 dB reduction in the soundpressure level is obtained when there is no gap between the two bodies. In contrast, the emitted soundpressure level increases by at least 8.0 dB for large gap distances (2.4D ≤ G ≤ 7D). Despite this, a 6.3 dB reduction in the soundpressure level is obtained due to a soundcancellation mechanism when the plate length is reduced to 0.26D and placed 5.6D downstream of the cylinder. The maximum sound reduction attainable is shown to be limited by the nonlinear unsteady stall process on the plate.
20130310T00:35:08Z
Ali, Mohamed Sukri Mat; Doolan, Con J.; Wheatley, Vincent

Aeolian tones generated by a square cylinder with a splitter plate
http://espace.library.uq.edu.au/view/UQ:229229
The generation of aeolian tones by the interaction of a low Reynolds number, low Mach number flow with a rigid square cylinder attached to a rigid thin flat plate is numerically investigated. When the length of the plate is varied from L = 0:5D to 6D, where D is the side length of the square cylinder, the results can be grouped into three distinct regimes. For the first regime (L . D), the aoelian tone levels decrease with increasing plate length. For the second regime (2D . L . 4D), the aeolian tone levels are always higher than the single square cylinder case and they increase with increasing plate length. For the third regime (5D . L . 6D), the levels of the aeolian tones decrease as the length of the plate increases but the levels are higher than the other regimes. These acoustic results can be explained in terms of the fluid mechanics occuring in the near wake of the cylinder.
20110215T15:27:01Z
Ali, Mohamed Sukri Mat; Doolan, Con J.; Wheatley, Vincent

Aeroassisted maneuvering of elastic tethered systems using a dissipative timestepping algorithm
http://espace.library.uq.edu.au/view/UQ:97171
20070824T01:05:11Z
Jokic, M. D.; Daniel, W. J. T.; Asokanthan, S. F.; Mee, D. J.

Aerodynamic design of hypersonic reentry flight HIFiRE 7
http://espace.library.uq.edu.au/view/UQ:316405
The HIFiRE (Hypersonic International Flight Research and Experimentation) program is a collaboration between the Australian Defence Science and Technology Organisation (DSTO) and the US Air Force Research Laboratory (AFRL) to develop and demonstrate fundamental hypersonic technologies, through computational analysis, ground testing and flight testing. HIFiRE 7 is the first of the freeflyer scramjet flights scheduled for launch in October 2010. It is an uncontrolled ballistic reentry experiment to measure thrust generated from two REST (RectangulartoElliptical Shape Transition) inlet scramjets mounted backtoback. The HIFiRE 7 payload will be launched aboard a spinstabilized twostage sounding rocket, utilizing an upandover ballistic trajectory. During the reentry phase, the payload will separate from the sustainer and continue as a freeflyer. The flight experiment will take place at Mach 8 between altitudes of ∼34km and 26km. This paper presents an overview the aerodynamic design of the freeflying vehicle from concept to the current configuration, including possible separation strategies. Copyright
20131127T14:47:23Z
Eggers, Thino; Silvester, Todd B.; Paull, Allan; Smart, Michael K.

Aerodynamic Drag Reduction for Satellites in Low Earth Orbit
http://espace.library.uq.edu.au/view/UQ:12294
Stalker (AIAA Paper 870403) has suggested that, by ejecting molecules directly upstream from the entire face of a satellite, it is possible to reduce the drag on a satellite in lowEarth orbit and hence maintain orbit with a total fuel mass (for forward ejection and conventional reaction rockets) less than the typical mass requirements of conventional rockets. An analytical analysis is presented here, as well as Monte Carlo simulations. These indicate that to reduce the overall drag on the satellite significantly, collisions between the freestream and ejected molecules must occur at least two satellite diameters upstream. This can be achieved if the molecules are ejected far upstream from the satellite’s surface through a sting that projects forward from the satellite. Using some estimates of what would be feasible sting arrangements, we find that the drag on the satellite can be reduced to such an extent that the satellite’s orbit can be maintained with a total fuel mass of less than 60% of that required for reaction rockets alone. Upstream ejection is effective in reducing the drag for freestream Knudsen numbers less than approximately 250, but not otherwise.
20070205T14:11:22Z
G. P. Cathcart; M. N. Macrossan

Aerodynamic Research for Hypersonic Applications in Australia
http://espace.library.uq.edu.au/view/UQ:209370
20100721T14:45:58Z
Houwing, A. F. P.; Gai, S. L.; Mudford, N. R.; Sandeman, R. J.; Boyce, R. R.

Aerogravityassist maneuvering of a tethered satellite system
http://espace.library.uq.edu.au/view/UQ:68891
Two new implementations of a tethered satellite system to provide aeroassist during a planetary flyby are investigated. In each mission scenario the interaction of the Martian atmosphere with an aerodynamic lifting surface, which is tethered to an orbiter, is used to perturb the flight path of the system. The aerodynamic forces generated by interacting with the atmosphere augment the gravity assist provided by the planet. In the first aerogravityassist maneuver the tethered satellite system has congruent post and preflyby configurations. The second scenario, which is referred to as a dualdestination mission, involves the system mass being separated during the flyby. Both of these aerogravityassist maneuvers are shown to facilitate significant, propellantfree velocity changes.
20070815T03:11:14Z
Jokic, MD; Daniel, WJT

Aerogravity assist manoeuvring of a tethered satellite system
http://espace.library.uq.edu.au/view/UQ:96124
20070824T00:15:56Z
Jokic, M. D.; Asokanthan, S. F.; Daniel, W. J. T.; Mee, D. J.

Aerosolassisted selfassembly of aluminum borate (Al18B4O33) nanowires into three dimensional hollow spherical architectures
http://espace.library.uq.edu.au/view/UQ:258983
20111022T18:31:42Z
Zhang, Jun; Elsanousi, Ammar; Lin, Jing; Huang, Yang; Elssfah, E. M.; Chen, Dongfeng; Gao, Jianming; Huang, Zhixin; Ding, Xiaoxia; Tang, Chengcun

Aerothermalstructural analysis of a rocketlaunched Mach 8 scramjet experiment: ascent
http://espace.library.uq.edu.au/view/UQ:362620
This paper reports on the methodology and results of a weakcoupled aerothermal–structural analysis on the ascent phase of the SCRAMSPACE Mach 8 scramjet flight experiment. This vehicle was essentially unshrouded during the flight trajectory, relying on the thin, 5 mm thick aluminum external shell of the payload to maintain structural integrity and protect the flight experiment. As such, understanding the thermal–structural response of the vehicle was imperative to mission success. Using two and threedimensional models, an iterative procedure was employed to compute the flowfield, convective heating, wall temperatures and structural coupling at flight times covering both peak heating and peak surface temperature. Accounting for such coupling resulted in a 150 K reduction in wall temperature compared to the more conservative cold wall assumption. Despite this, peak temperatures remained of the order of 550 K. Further, thermally induced stresses within these regions were in excess of four times the material failure limits. Irreversible material failure during ascent was therefore concluded likely to occur on the external shell. Two alternate materials, steel 1006 and copper, were therefore assessed with the results indicating that steel sections on the external shell resulted in the best thermal–structural response of the payload.
20150609T02:25:53Z
Capra, Bianca R.; Brown, L. M.; Boyce, R. R.; Tirtey, S. C.

Aerothermochemical realgas effects of transverse jet interactions for Martian Atmosphere
http://espace.library.uq.edu.au/view/UQ:196617
This research focusses on the aerothermodynamics of hypersonic vehicles  a field in which Australia maintains world leadership in niche areas. In particular, we are concerned with the complex flow structures that occur in both external and internal (scramjet engine) flowpaths associated with such vehicles, and for scramjet flowpaths, with the coupling between these structures and the combustion processes that lead to thrust generation.
20100225T08:55:33Z
Deepak, N. R.; Boyce, R. R.

Aerothermodynamic investigation of inductively heated CO2 plasma flows for Mars entry testing
http://espace.library.uq.edu.au/view/UQ:350391
This paper presents the characterization of an inductively coupled CO2 plasma relevant for Mars entry. Key plasma parameters are measured using Two Photon Absorption LaserInduced Fluorescence (TALIF), Optical Emission Spectroscopy (OES) and a HighSpeed Camera (HSC) as nonintrusive diagnostic methods. In addition heat flux, enthalpy and total pressure are intrusively probed to supplement the characterization. TALIF provides data about translational temperature, velocity and the density of ground state atomic oxygen. From OES rotational and vibrational temperatures for identified molecular species and excitation temperatures for atomic species are derived. Preliminary HSC results show the pulsing behaviour of the generator and, in combination with bandwidth filters, atomic emission distributions. The diversity of the applied measurement techniques offers an extensive characterization of the flow, hence enabling the identification of suitable test conditions for the early stages of Martian entries.
20150202T16:16:51Z
Marynowski, T.; Loehle, S.; Zander, F.; Meindl, A.; Fasoulas, S.

A fast simulation method with arbitrary viscosity law
http://espace.library.uq.edu.au/view/UQ:9927
A new approach to DSMC collision modelling, called viscosityDSMC or muDSMC, is described. The characteristic collision crosssection (of any standard collision model) is made to vary from cell to cell, based on the timeaveraged temperature in each cell. In this way the collision model will display the ChapmanEnskog viscosity given by any desired viscosity law mu = mu(T), including a curve fit to experimental data. For example, we show that a hard sphere collision model, with hard sphere collision probability, used with a different molecular size in each cell, can reproduce a Sutherland viscosity law. Similarly, by making the reference crosssection of a VHS collision model a function of the temperature, we show that the VHS collision model can reproduce the viscosity given by the more complicated generalized hard sphere (GHS) collision model. We calculate the structure of a plane 1D shock using the new approach and show that the results agree closely with those from standard DSMC using the GHS model. A particularly simple, and computationally efficient, method is to use the Maxwell VHS model, in which all collision pairs are equally likely, as the basis of the new method. That is, the characteristic size of the maxwell VHS model is varied from cell to cell, based on the timeaveraged cell temperature and the (arbitrary) desired viscosity law mu = mu(T). Since the timeaveraged cell temperature is available in standard DSMC as part of the procedures which determine the steady state flow, the new methods are as fast as, or faster than DSMC using the standard VHS model. Unlike more complicated models with realistic viscosities, the new procedures are compatible with the BorgnakkeLarsen energy exchange scheme and the established chemistry models for DSMC. ©2005 American Institute of Physics
20050225T00:00:00Z
Macrossan, M. N.

A first quantitative XPS study of the surface films formed, by exposure to water, on Mg and on the MgAl intermetallics: Al3Mg2 and Mg17Al12
http://espace.library.uq.edu.au/view/UQ:183649
20090904T10:28:17Z
Liu, M.; Zanna, S.; Ardelean, H.; Frateur, I.; Schmutz, P.; Song, G.L.; Atrens, A.; Marcus, P.

A flexible extended warranty and related optimal strategies
http://espace.library.uq.edu.au/view/UQ:130659
The choice of extended warranties (EWs) currently available to consumers is extremely limited. Their EW purchase decisions have to be made at or very close to the time that they purchase the products and, at this point, they are uncertain about item reliability, future operating costs, and usage time before replacement. In this paper, we discuss an EW that offers more flexibility and we investigate optimal pricing strategies for the EW provider and optimal maintenance and replacement strategies for the consumer.
20080218T15:41:35Z
Jack, N.; Murthy, D. N. P.

A focused review on nanoscratchinginduced deformation of monocrystalline silicon
http://espace.library.uq.edu.au/view/UQ:289802
This focused review includes two parts. In the first part, the previous studies on the deformations of monocrystalline Si induced by nanoscratching were summarised. In the second part, our recent studies on the scratchinginduced deformation of Si were systematically presented. The studies have demonstrated that lateral force in nanoscratching plays a key role in the amorphization and phase transformation of Si under mechanical loading. The deformation route of Si appears to be different from those reported from the nanoindentation studies.
20130125T07:39:16Z
Wu, Yueqin; Huang, Han; Zou, Jin

A foundry molding sand expert system based on artificial neural network
http://espace.library.uq.edu.au/view/UQ:186771
20091117T13:58:48Z
Huang, Tianyou; Wang, Gui; et al.

A framework for relative equipment localisation
http://espace.library.uq.edu.au/view/UQ:135355
20080415T16:06:13Z
Green, M.; Williams, I.; McAree, P. R.

Afterbody Flow Of a Dissociating Gas Downstream of a Blunt Nose
http://espace.library.uq.edu.au/view/UQ:8863
A freepiston driven shock tunnel, operating in the nonreflected mode, was used to obtain a strongly dissociating flow of pure nitrogen (Mach 5.66) over a blunt nosed body, 65 mm long. The flow speed is approximately 6 km/s and the Damkohler number of O(1) indicates that the flow is in chemical nonequilibrium. The useful test time is shorter than for conventional shock tunnel operation but the "priorsteadyflow" technique has been used to establish a fully developed flow. Interferograms of the afterbody flow have been made and compared with results obtained from a finite volume (kinetic theory based) CFD method the "Equilibrium Flux Method" for chemically reacting flows. The results show good agreement between experiments and computations. The experiments were perfomed in the T3 shock tunnel at the Australian National University. [For more details of the CFD method see M N Macrossan J Comput Physics v80, p204 1989. For more details of the flow and the experiments see M N Macrossan J Fluid Mechanics v207, p167 1990].
20051209T00:00:00Z
Macrossan, Michael N.; Stalker, Ray J.

A fuel cell stack
http://espace.library.uq.edu.au/view/UQ:263858
20111220T13:49:52Z
Odabaee, Mostafa; Hooman, Kamel

A fully coupled gas flow, coal deformation and thermal transport model for the injection of carbon dioxide into coal seams
http://espace.library.uq.edu.au/view/UQ:301215
20130527T15:47:43Z
Qu, H; Liu, J.S; Zhongwei Chen; Connell, Pan; Connell, L.

A fully coupled model for caprock sealing efficiency
http://espace.library.uq.edu.au/view/UQ:353576
The sealing integrity of a suitable low permeability caprock is one of the most important issues to the safety of longterm CO2 sequestration in a saline aquifer over long geological time periods. From the microscopic viewpoint, caprocks contain microcracks which make caprocks anisotropic in mechanical and hydraulic properties. Additionally, the growth of microcracks could lead to permeability increasing exponentially, which extremely harms caprock sealing efficiency. To assess caprock sealing efficiency accurately, a fully coupled model should include caprock deformation, twophase flow, CO2 sorption and damage evolution of caprocks. The purpose of this paper is to present such a model for investigating caprock sealing efficiency. Firstly, a conceptual model is proposed for the CO2/water flow in a caprocks with microcracks. In this model CO2/water flow is described by twophase flow equation with variable porosity and permeability. This provides a solid basis to the further development of numerical simulations for the caprock sealing efficiency assessment. Finally, this fully coupled mathematical model is applied to a caprock layer to investigate the combined effect of fully coupling processes on the caprock sealing efficiency. Model results demonstrate that the damage effects on the caprock sealing efficiency are significant.
20150311T10:09:30Z
Peng, Yan; Liu, Jishan; Pan, Zhejun; Connell, Luke; Chen, Zhongwei

A fundamental study of water jet assist blasthole drilling in sandstone and greywacke
http://espace.library.uq.edu.au/view/UQ:101875
20070823T20:29:36Z
Dean, W. R.; Grandone, S. B.; Tadic, D. M.; Gledhill, M. E.; Qin, Z.

A Fundamental Study of Water Jet Assist Blast Hole Drilling in Sandstone and Greywacke
http://espace.library.uq.edu.au/view/UQ:2829
20060419T09:19:05Z
Dean, W. R.; Grandone, S.; Tadic, D.; Gledhill, M.; Qin, J.

A fundamental study on photooxidative degradation of linear low density polyethylene films at embrittlement
http://espace.library.uq.edu.au/view/UQ:276158
Film embrittlement criteria were determined for photooxidative degradation of linear low density polyethylene (LLDPE) films by using a range of characterisation techniques: tensile, hightemperature GPC, MASNMR, FTIRATR, WAXS and SAXS. The key embrittlement criteria was the loss of 95% elongation at break and the reduction in interlamellar distance, reduced down to approximately 30–50 Å, as a result of recrystallisation of mobile short chain fragments produced from chain scission reaction. Interlamellar thinning correlated well with the changes in double yield points seen in the tensile data, where the absence of the second yield point signified that the tie molecules at the lamellar interface underwent chain scission and could no longer transfer the tensile stress to reach caxis slip of the lamellar crystals. This was also supported by a reduction in amorphous–lamellar interfacial width with ageing time, extracted from SAXS data using the linear correlation function.
20120625T09:36:05Z
Hsu, YuChieh; Weir, Michael P.; Truss, Rowan W.; Garvey, Christopher J.; Nicholson, Timothy M.; Halley, Peter J.

A general crystallographic model of fcc/bcc(bct) martensitic nucleation and growth in steels
http://espace.library.uq.edu.au/view/UQ:123345
The crystallography of fcc/bcc(bct) martensite transformation, including nucleation and growth, has been discussed from the viewpoint of invariantline and Olattice theory. The formation of martensite is accomplished by the immigration of welldefined glissile interface (121)(fcc) type and its misfit dislocations can produce the lattice invariant deformation (LID) on the basis of phenomenal theory of martensitic crystallography (PTMC), however, LID is retarded slightly after the migration of interphase (121)(fcc), i.e. a thin platelike zone exists without LID in martensite near the welldefined interface. When the temperature reduces to the Ms point, the lattice parameter of austenite matrix is root 3/2 times that of the martensite without LID. This critical condition for spontaneous transformation agrees with that the stack fault energy in matrix is less than zero according to Olson and Cohen's nucleation model.
20080125T16:30:39Z
Yang, J. B.; Yang, Z. G.; Qiu, D.; Zhang, W. Z.; Zhang, C.; Bai, B. Z.; Fang, H. S.

A generalised multiple mapping conditioning approach for turbulent combustion
http://espace.library.uq.edu.au/view/UQ:178306
This paper follows the evolution in understanding of the multiple mapping conditioning (MMC) approach for turbulent combustion and reviews different implementations of MMC models. As the MMC name suggests, the original version represents a consistent combination of CMCtype conditional equations (conditional moment closure) and generalised mapping closure. It seems that the strength of the MMC model, and especially that of its stochastic version, lies in a more general (and much more transparent) interpretation. In this new generalised interpretation, we can replace complicated derivations by physical reasoning and the model appears to be a natural extension of modelling approaches developed in recent decades. MMC can be seen as a methodology for enforcing certain known characteristics of turbulence on a conventional mixing model. This is achieved by localising the mixing operation in a reference space. The reference space variables are selected to emulate the properties of a turbulent flow which have a strong effect on reactive quantities. The best and simplest example is an MMC model which has a single reference variable emulating the mixture fraction. In diffusion flames turbulent fluctuations of reacting quantities are strongly correlated with fluctuations of the mixture fraction. By making mixing local in the reference mixture fraction space a CMCtype mixing closure is enforced. In the original interpretation of MMC the reference variables are modelled as Markov processes. Since the reference variables should emulate properties of turbulent flows as realistically as possible the next step, and the basis of generalised MMC, is to remove the Markovian restriction and set reference variables equal to traced Lagrangian quantities within DNS or LES flow fields. Indeed, no Markov value can emulate the mixture fraction better than the mixture fraction itself. (Using a Markov vector process of dimension higher than the number of conditioning variables represents a more economical alternative for producing reference variables in generalised MMC.) The generalised MMC approach effectively incorporates the mixture fractionbased models, the PDF methods and LES/DNS techniques into a single methodology with possibility of blending useful features developed previously for conventional models. The generalised approach to MMC stimulates a more flexible understanding of simulations using sparsely placed Lagrangian particles as tools that may provide accurate joint distributions of reactive scalars at relatively low computational cost. The physical reasoning behind the new interpretation of MMC is supported by example computations for a partially premixed methane/air diffusion flame (Sandia Flame D). The scheme utilises LES for the dynamic field and a sparseLagrangian filtered density function method with MMC mixing for the scalar field. Two different particle mixing schemes are tested. Simulations are performed using only 35,000 Lagrangian particles (of these only 10,000 are chemically active) on a single workstation. The relatively low computational cost allows the use of realistic chemical kinetics containing 34 reactive species and 219 reactions.
20090605T14:53:26Z
Cleary, Matthew; Klimenko, Alexander Y.

A generalized nonequilibrium binary scaling for shock standoff on hypersonic blunt bodies
http://espace.library.uq.edu.au/view/UQ:97167
20070824T01:05:03Z
Inger, G. R.; Higgins, C. E.; Morgan, R. G.

A General SingleSource Route for the Preparation of Hollow Nanoporous Metal Oxide Structures
http://espace.library.uq.edu.au/view/UQ:198504
A hole in one: Hollow nanoporous structures are prepared by controlled decompositiondissolution. The partial thermal decomposition of transitionmetal salts forms a metal oxide shell on the surface of the metal salt particles. Acid washing removes the metal salt cores, resulting in hollow nanoporous metal oxide shells (see picture). This new strategy provides a templatefree singlesource route to hollow structures.
20100310T08:51:09Z
Wang, L. Z.; Tang, F. Q.; Ozawa, K.; Chen, Z. G.; Mukherj, A.; Zhu, Y. C.; Zou, J.; Cheng, H. M.; Lu, G. Q.

A genetic algorithm optimization for a finned channel performance
http://espace.library.uq.edu.au/view/UQ:138275
Compared to a smooth channel, a finnedchannel provides higher heat transfer coefficient and increasing the fin height enhances the heat transfer. However, this heat transfer enhancement is associated with an increase in the pressure drop. This leads to an increased pumping power requirement so that one may seek an optimum design for such systems. The main goal of this paper is to define the exact location and size of fins in such a way that a minimal pressure drop coincides with an optimal heat transfer based on the genetic algorithm. Each arrangement of fins is considered as a solution of the problem (an individual for genetic algorithm). An initial population is generated randomly at the first step. Then the algorithm has searched among these solutions and made new solutions iteratively by its functions to find an optimum design as reported in this article.
20080513T10:23:13Z
Mousavi, S. S.; Hooman, K.; Mousavi, S. J.

Agglomeration and bending of equiaxed crystals during solidification of hypoeutectic Al and Mg alloys
http://espace.library.uq.edu.au/view/UQ:190594
Agglomeration and bending of equiaxed crystals were studied by microstructural characterization of specimens produced by nearstatic cooling, highpressure die casting and Thixomolding®, where the solidifying crystals experience different levels of mechanical stresses. EBSD was used to acquire statistical grain misorientation data which is linked to crystal agglomeration and bending behavior during solidification. An aluminum alloy and two magnesium alloys were used to compare grain misorientations for different crystal structures. The length fraction of lowenergy grain boundaries in HPDC and Thixomolded samples was substantially higher than in “statically cooled” samples. This is attributed to the high shear stresses and pressure applied on the solidifying alloy, which promote crystal collisions and agglomeration. Ingrain misorientations were found to be significant only in branched dendritic crystals which were subjected to significant shear stresses. This is related to the increased bending moment acting on long, protruding dendrite arms compared to more compact crystal morphologies.
20091220T00:06:10Z
Otarawanna, S.; Gourlay, C. M.; Laukli, H. I.; Dahle, A. K.

Aggregation of Dopant Cations and their effect on Electrical Conductivity of Yttrium Doped Ceria
http://espace.library.uq.edu.au/view/UQ:138556
20080515T17:08:04Z
Ou, D.R.; Mori, T.; Ye, F.; Zou, J.; Drennan, J.

A grinding protocol for the fabrication of micro/meso aspheric moulds for optic applications
http://espace.library.uq.edu.au/view/UQ:282641
This paper summarised our recent results on the development of grinding technologies for the fabrication of aspheric components at micro/meso scales made of cemented tungsten carbide. Based on these results, a grinding protocol was proposed for the fabrication of aspheric moulds. The protocol includes the understanding of deformation and removal mechanisms of hard and brittle materials involved in grinding, the preparation of grinding wheels, the compensation of profiling errors and the optimisation of the grinding process.
20121001T19:59:42Z
Huang, Han

A hierachical blast management system
http://espace.library.uq.edu.au/view/UQ:147621
20080606T13:42:00Z
La Rosa, D. M.; Chitombo, G. P.

A hybrid methodology for secondary fragmentation prediction in cave mines
http://espace.library.uq.edu.au/view/UQ:220696
20101116T17:15:51Z
Pierce, M.; Weatherley, D. K.; Kojovic, T.

A hybrid signal preprocessing approach in processing ultrasonic signals with noise
http://espace.library.uq.edu.au/view/UQ:217392
20100929T08:41:03Z
Palanisamy, S.; Nagarajah, C.R.; Graves, K.; Iovenitti, P.

A hydrogen storage system utilising ascast magnesium based alloys
http://espace.library.uq.edu.au/view/UQ:327103
20140328T13:33:59Z
Nogita, Kazuhiro

Aircooled microporous heat exchangers for thermal management of fuel cells
http://espace.library.uq.edu.au/view/UQ:274366
This paper presents 3D numerical simulation of an aircooled metal foam heat exchanger with potential application in thermal management of fuel cell systems in general and Proton Exchange Membrane Fuel Cells, PEMFCs, in particular. It has been shown that the new design can lead to a uniform temperature distribution for the heated plate especially at higher air flow speeds. The heat transfer enhancement because of the foams leads to an increase in the pressure drop which is, interestingly, comparable to that of watercooled PEMFCs. Other potential benefits of the application of metal foams for fuel cell thermal management are briefly discussed and estimated.
20120521T22:20:58Z
Boyd, Ben; Hooman, Kamel

A kalmanfilter based inertial navigation system processor for the SCRAMSPACE 1 hpersonic flight experiment
http://espace.library.uq.edu.au/view/UQ:293388
20130311T12:28:34Z
Creagh, Michael; Beasley, Peter; Dimitrijevic, Igor; Brown, Melrose; Tirtey, Sandy

A K Dahle and D H St John, "Prevent banded defects in highpressure diecast magnesium alloys", Invited Feature Article
http://espace.library.uq.edu.au/view/UQ:139558
20080610T10:44:32Z
Dahle, A. K.; St John, D. H.

A kinetic theory solution method for the NavierStokes equations
http://espace.library.uq.edu.au/view/UQ:11392
The kinetictheorybased solution methods for the Euler equations proposed by Pullin and Reitz are here extended to provide new finite volume numerical methods for the solution of the unsteady NavierStokes equations. Two approaches have been taken. In the first, the equilibrium interface method (EIM), the forward and backwardflowing molecular fluxes between two cells are assumed to come into kinetic equilibrium at the interface between the cells. Once the resulting equilibrium states at all cell interfaces are known, the evaluation of the NavierStokes fluxes is straightforward. In the second method, standard kinetic theory is used to evaluate the artificial dissipation terms which appear in Pullin's Euler solver. These terms are subtracted from the fluxes and the NavierStokes dissipative fluxes are added in. The new methods have been tested in a 1D steady flow to yield a solution for the interior structure of a shock wave and in a 2D unsteady boundary layer flow. The 1D solutions are shown to be remarkably accurate for cell sizes large compared to the length scale of the gradients in the flow and to converge to the exact solutions as the cell size is decreased. The steadystate solutions obtained with EIM agree with those of other methods, yet require a considerably reduced computational effort.
20061220T09:34:56Z
Macrossan, M. N.; Oliver, R. I.

AlAIN composites consolidated from partially nitride aluminum alloy powders by Equal Channel Angular Pressing (ECAP)
http://espace.library.uq.edu.au/view/UQ:239022
AlAlN composite powders were fabricated through nitriding aluminium powder mixtures of AA 60612%Mg1%Sn3%Nylon at 560 °C in nitrogen at atmospheric pressure. Each nitrided particle is enveloped by an insitu formed AlN shell, which is a nanocomposite of AlAlN, comprising nanoscale AlN whiskers and an Al matrix. The thickness of the ‘AlN shell’ increases with nitridation time, through which the AlN content can be readily controlled. The partially nitrided powders were consolidated using back pressureassisted Equal Channel Angular Pressing (ECAP) at 200 °C, with a view to dispersing the nanoscale AlN. It was found that the processing behaviours of the AlAlN composite powders were significantly affected by the AlN content. The ‘AlN shells’ were difficult to fragment as they deformed readily during ECAP. As a result, agglomeration or segregation of the AlN phase was observed after multipasses of ECAP, particularly at large volume fractions. The attendant microstructures show shear banding and surface cracking when the AlN content is more than 20 vol.%. However, at a low volume fraction of AlN (8.9%), multipasses of ECAP resulted in a dense AlAlN microstructure with a reasonable dispersion of the AlN in the matrix.
20110325T15:35:38Z
Yu, Peng; Bettles, Colleen; Schaffer, G. B.; Qian, Ma

Al/AlN layered composites by direct nitridation of aluminum
http://espace.library.uq.edu.au/view/UQ:67375
20070815T02:39:55Z
Hall, BJ; Schaffer, GB; Ning, Z; McPhee, WAG; Miller, DN; Drennan, J; Cumming, DJ

A Lambwavebased technique for damage detection in composite laminates
http://espace.library.uq.edu.au/view/UQ:199913
This paper presents the application of Lamb waves to inspect damage in composite laminates. The proposed methodology employs a network of transducers that are used to sequentially scan the structure before and after the presence of damage by transmitting and receiving Lamb wave pulses. A damage localization image is reconstructed by analyzing the crosscorrelation of the scatter signal envelope with the excitation pulse envelope for each transducer pair. A potential damage area is then reconstructed by superimposing the image observed from each actuator and sensor signal path. Both numerical and experimental case studies are used to verify the proposed methodology for composite laminates. Threedimensional finite element models with a transducer network consisting of four transducer elements are used in the numerical case studies. The experimental case studies employ a transducer network using four piezoelectric transducers as transmitter elements and a laser vibrometer to measure the response signals at four locations close to the transducers. The results show that the method enables the reliable detection of structural damage with locating inaccuracies of the order of a few millimeters inside as well as outside of an inspection area of 100 x 100 mm(2).
20100319T10:51:42Z
Ng, C. T.; Veidt, M.

Al based alloys containing amorphous and nanostructured phases
http://espace.library.uq.edu.au/view/UQ:196003
Nanostructured or partially amorphous Albased alloys are attractive candidates for advanced highstrength lightweight materials. The strength of such materials is often 2  3 times higher than the strength of commercial crystalline alloys. Further property improvements are achievable by designing multiphase composite materials with optimized length scale and intrinsic properties of the constituent phases. Such alloys can be prepared by quenching from the melt or by powder metallurgy using mechanical attrition techniques. This paper focuses on mechanically attrited Albased powders containing amorphous or nanocrystalline phases, Albased MMCs containing metallic glass reinforcement and on their consolidation into bulk specimens. Selected examples of mechanical deformation behavior are presented, revealing that the properties can be tuned within a wide range of strength and ductility as a function of size and volume fraction of the different phases.
20100219T15:09:16Z
Eckert, J.; Calin, M.; Yu, P.; Zhang, L. C.; Scudino, S.; Duhamel, C.