Theses

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Included in the Research Theses collection are Masters, PHD and Professional Doctorate theses.
Masters and PHDs by coursework theses are included in the Honours and Coursework Theses collection. Some schools may choose to include Honours theses which make a significant contribution to knowledge.
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Open Access
1. The geology and petrography of an Archaean inlier, south of Normanville. 2. The origin of the 'Houghton' granulite.
(1972) Davies, M. B.; School of Earth and Environmental Sciences, Geology & Geophysics
1. Detailed mapping established definite rock units within the Archaean inlier south of Normanville. The distribution of the rock types is suggestive of a major antiformal structure. Only metamorphic layering is recognised in the area. The first Archaean orogeny produced this layering and reached upper amphibolite grade of metamorphism as defined by the minerals sillimanite, garnet, diopside and scapolite. The temperature and pressure conditions were ~750C and 2-3 Kbars. This was established using mineral assemblages and the presence of considerable partial melting, pegmatitic masses and migmatites. This same orogeny was also responsible for the development of a strong schistosity, which was always parallel to the metamorphic layering. A Proterozoic orogeny produced a strong crenulation of the schists. This crenulation is parallel to the fold axis of a major antiform which plunges 35deg to 138deg. The deformation reached biotite grade of metamorphism as shown by the minerals biotite, sericite and epidote, which, commonly replace the higher grade minerals. An antiform overturned to the west was the major structure. Its under limb was sheared away, so that the inlier represents the eastern limb only. The western outcrops of the inlier represent the shear zone. 2. Geochemical analyses of the Houghton granulite suggest a sedimentary origin. This, coupled with its conformability with the surrounding rocks, and its association with a zircon rich meta-quartzite, support this conclusion.
Open Access
1064 nm injection mode-locked Nd:YAG laser optimized for guide star applications.
(2010) Rutten, Thomas P.; Munch, Jesper; Veitch, Peter John; School of Chemistry and Physics
In recent years, the emergence of powerful, sodium-resonant laser sources has led to a dramatic improvement in resolution at many of the world’s large aperture observatories. The lasers are used to create artificial beacons (or guide stars) by fluorescing atmospheric sodium. Light from the beacon, returning from altitude, probes the intervening turbulence and the phase distortions detected are subsequently corrected using adaptive optics. Near-diffraction limited imaging has now been achieved on observatories with diameters up to 8 m using this technique. Future 30-100 m diameter telescopes will require new laser sources having higher average powers and innovative pulse formats to implement new forms of atmospheric tomography and correction. In this thesis I present the design and development of a new laser system for this purpose. The laser design that I describe uses sum frequency generation (SFG) of 1064 nm and 1319 nm Nd:YAG lasers to produce the sodium wavelength, and introduces the novel application of injection mode-locking as a robust method to control the lasers wavelength and bandwidth. The high peak power and low timing jitter of the mode-locked (micro) pulses allows for efficient SFG of the 1064 and 1319 nm beams. Each slave laser is Qswitched and the duration of the Q-switched (macro) pulses are optimised to reduce star elongation and bleaching of the sodium. The experimental work presented in this thesis is focused on the realization of a 1064 nm injection mode-locked slave laser, whose performance is optimised for use in the SFG guide star system. The work can be roughly divided into two sections. Firstly, results are presented from a low average power proof of principle laser which was used for risk reduction experiments, then secondly, a higher average power laser using a new laser head design is presented. With the proof of concept laser it is shown that the injection mode-locking technique is robust and can be used to generate an ideal pulse burst with both wavelength and bandwidth control. A new method of Q-switched pulse stretching was implemented and the results show that the Q-switched pulses can be extended by a factor of 4.5 without a reduction in pulse energy. The later part of the experimental work consists of a description of the design, construction and testing of a new high average power laser head used to generate the power levels required for the final guide star system. The laser head uses a zigzag Nd:YAG slab, pumped from each side by high average power laser diode arrays. This laser is shown to be capable of generating one of the highest average powers reported in the literature for an electro-optically Q-switched, diffraction limited Nd:YAG laser in a stable cavity.
Open Access
The 1300AD dacite pumice eruption, Rinjani Volcano, East Sunda Arc: petrology, petrogenesis and plumbing
(2009) Meegan, N. K.; School of Physical Sciences
Physical controls on fractional crystallisation in subduction settings around the globe are the focus of much discussion within academia. It is frequently observed that the typical magma to be erupted in arc settings is andesite from the differentiation of partially melted peridotite mantle wedge. It is less common in these settings to see more felsic end member magmas such as dacite or rhyolite being erupted in cataclysmic events. Discussion has arisen into what physical process or processes can drive a volcano, or set of volcanoes, within an arc to produce dacite or rhyolite magmas where fractional crystallisation is known to be the process of initial crystallisation. Research into these processes can be applied to Mount Rinjani (Lombok) within the Sunda Arc system, where the normally composite andesite volcano produced a cataclysmic eruption of dacite magma known as the Rinjani Pumice at 1300AD. Data is presented here in order to investigate processes within the sub-volcanic magma plumbing at Rinjani, primarily using volatiles from melt inclusions, coupled with petrology, pressure, temperature and water saturation estimates. It is theorised that ascent-driven crystallisation from a parent basalt drove fractional crystallisation to andesite composition beneath Rinjani volcano. Water undersaturated conditions induced ascent of the andesite magma to a shallow reservoir at ~3 kbar at temperatures ~1015 °C, with water saturation ~3.7 weight percent. Melt inclusion data from these same crystals reveals the interstitial liquid in the andesite magma to be of evolved dacite composition (~66 wt % SiO2) compared to the andesite (~50-54 wt % SiO2). Critical crystallinity is the physical process believed to have acted upon fractional crystallisation where the percentage of crystals forming exceeded the ability of the magma chamber to convect within this reservoir and therefore physical separation of the evolved dacite liquid from the andesite magma occurred. The buoyant dacitic liquid ascends to another shallow reservoir directly beneath Rinjani volcano and reaches its saturation pressure at 1.8 kbar at a temperature of ~900 °C, with water saturation increased to ~5 wt %. Sub-plinian cataclysmic eruption of the 1300AD Rinjani Pumice occurred due to pressure increase involved in saturation of the dacite, and syn-eruptive degassing aids in excavating the western flank of the Rinjani stratocone leaving a caldera. Subsequent volcanism occurs where the magma ascent path migrates west producing more cataclysmic eruptions increasing the volume of the edifice. Today, resurgent volcanism can be seen in the central eastern part of Segara Anak lake at Gunung Baru within the Rinjani caldera to produce basalt and andesite lavas. The application of physical mechanisms acting upon fractional crystallisation proposed here may be applied to other arc settings around the globe, where fractional crystallisation is found to be the primary driving force of felsic end member cataclysmic eruptions at what is typically an andesitic arc.
Open Access
16 across.
(2009) Gramazio, Holly; Jose, Nicholas; Costello, Moya; School of Humanities : English
The creative work, 16 Across, examines the possibilities of online fiction through practice. It comprises forty stories which take place over the course of a day late in March 2006. The stories are linked to a crossword that follows the shape of Adelaide's street layout. Each story acts as a clue to one of the words in the crossword grid, and takes place in the part of Adelaide corresponding to the location of that word. There is a considerable intersection of characters, places and times; specifically, where two clues overlap, there is an intersection between their respective stories. The stories in the top left (north-west) corner take place in the very early morning, and the day progresses as the stories move towards the bottom right and late night; a forty-first story is set the following morning and, in the online version of 16 Across, only becomes visible to readers who have successfully completed the crossword. The exegesis investigates the history of online fiction, the developments which have brought it to its current state, and its possibilities for the future. It places online fiction within a larger history of electronic fiction, and examines the differences between online fiction and offline fiction, whether electronic or paper. By looking at works which have made the transition between online and offline fiction, it examines how the experience of a reader of online fiction is different from that of a reader of offline fiction. It also looks at the technical and social contexts in which online fiction exists. Finally, the characteristics which emerge from this examination are used to predict the directions, both creative and commercial, in which online fiction may move. It is suggested that the future of online fiction lies, to a great extent, with writing which is increasingly willing to blur the lines between games and stories or between work time and leisure time, or between fact and fiction, or between writer and reader.
Open Access
1st Anzac Corps and the Battle of Pozières Ridge, 1916
(2014) Hampton, Meleah Elizabeth; Prior, Robin Geoffrey; Sheffield, Gary; School of History and Politics
The first major action of the 1st Anzac Corps on the Western Front was the Battle of Pozières Ridge, which was conducted from 23 July to 3 September 1916. During this time the three divisions of 1st Anzac Corps rotated in and out of the line twice, each time conducting one or more offensive operations against heavily-defended German positions. At its conclusion, the fighting around Pozières and Mouquet Farm had to its record a very high casualty rate for only the most modest of territorial gains. This thesis examines the series of operations conducted by 1st Anzac Corps during the six weeks of the Battle of Pozières Ridge. These operations are more representative of the Somme than the large attacks like the ill-fated first day or the night attacks of 14-15 July. On any given day during the Battle of the Somme only a small percentage of the line was engaged in fighting the enemy – almost invariably in the same kind of limited, set-piece attacks made by 1st Anzac Corps at Pozières and Mouquet Farm. The particular focus of this thesis is on the agency of mid to low levels of command in the military hierarchy during this battle. Detailed reports, orders and message of the battle survive in the archives in the Australian War Memorial which are in so many cases simply unavailable for other contemporary British or Dominion formations. They allow a detailed examination of the fighting in this area that is simply not possible in so many cases because of a scarcity of records at lower levels. They reveal a wide range of operational approaches at brigade, battalion, and in some cases company level. They also, importantly, describe the point at which diversity and innovation could not have any impact at these lower levels as a result of problems at a higher level of command. After some initial success, 1st Anzac Corps began conducting operations that diminished in scope, with shorter objectives, smaller attacking forces and serious problems with coordination between the artillery and the infantry. Forward movement was increasingly limited and only correlated to Reserve Army’s strategic vision in the vaguest of terms. The Australian memorial at the Windmill carries the words of Charles Bean, who said ‘Australian troops… fell more thickly on this ridge than on any other battlefield of the war’. This study of the battle reveals that more often than not, this was an unnecessary waste of lives and resources for the most negligible of gains, if any gains were made at all.
Open Access
(1→3)-β-D-glucan synthases of plants.
(2003) Jacobs, Andrew Keith; Fincher, Geoffrey Bruce; Burton, Rachel Anita; School of Agriculture and Wine
This thesis investigates the involvement of the plant glucan synthase-like or GSL genes in the formation of callose. Callose is a (1→3)-β-D-glucan widely distributed in higher plants. During normal plant growth, callose is found as a transitory component of the cell plate in dividing cells, it is a major component of pollen mother cell walls and pollen tubes, and is found as a structural component of plasmodesmatal canals, and is also in abscission zones and the phloem of dormant tissues. Callose is also deposited between the plasma membrane and the cell wall following exposure of plants to a range of abiotic and biotic stresses, including wounding, dessication, metal toxicity and microbial attack. Gene isolation was conducted in ryegrass, but functional analyses were conducted in barley. Ultimate proof of function of a single GSL gene was achieved in the plant model Arabidopsis.
Open Access
2 um Lasers for Cryogenic-Silicon Gravitational Wave Detectors
(2025) Holmes, Zachary James; Veitch, Peter; Ng, Sebastian; School of Physics, Chemistry and Earth Sciences
Next-generation gravitational wave detectors may use cryogenic-silicon test mass mirrors to reduce the impact of thermal noise and absorption-induced wavefront distortion. Unfortunately, silicon is opaque at 1064 nm, which is the wavelength used by the current generation of detectors. A single-frequency, diffraction-limited, linearly-polarised, high power laser with a wavelength in the 1.5-2.05 μm band must therefore be developed. The preferred architecture is a master oscillator followed by a chain of power amplifiers, sometimes referred to as a master-oscillator-power-amplifier (MOPA). Additionally, the coherent combination of several high power laser beams may be required. This thesis reports the investigation of several technologies that could be used in such a laser source: stabilised laser diodes for use as a master oscillator, a low power polarisation-maintaining fibre pre-amplifier, and the coherent combination of multiple laser beams using a ring resonator. Laser diode linewidths have been progressively narrowing and they exhibit wide frequency modulation bandwidths. Thus, in Chapter 2, I report on the stabilisation limitations of a 1645nm distributed feedback (DFB) laser diode using an optical phaselock. Bandwidth limitations and achievable noise suppression magnitudes were investigated, and the likelihood that DFB diodes could be a potential master or seed oscillator is discussed. The investigation of a wavelength-tunable 2 μm external cavity diode laser (ECDL) is described in Chapter 3. The power, polarisation, wavelength stability, and noise characteristics were investigated in the context of detector requirements. The ECDL is also compared to the DFB diode and the feasibility of such diodes as master oscillators is evaluated. The development of a thulium-doped silica fibre pre-amplifier is described in Chapter 4. This consists of the amplification of 2 μm laser diodes to investigate amplifier gain, efficiency, and noise performance. The maximum output power of narrow-linewidth fibre amplifiers is limited by optical nonlinearities. Larger core diameters and lower numerical apertures are used, although this can result in transverse mode instability and unacceptable beam jitter. Thus, in Chapter 5, I describe the coherent combination of multiple laser beams using a ring resonator. The scheme is investigated and high combination efficiency is demonstrated, along with the simultaneous spatial mode filtering of the input beams.
Open Access
A 210,000-year reconstruction of subtropical climates from Fern Gully Lagoon, North Stradbroke Island (Minjerribah), Australia
(2020) Kemp, Christopher Wilde; Tibby, John; Barr, Cameron; Arnold, Lee; School of Social Sciences : Geography, Environment & Population
Climates during past interglacials may be an analogue for future climate change. Robust reconstructions of past interglacial climates are important for providing these analogues, as well as for better understanding ecosystem responses that are likely to accompany an increase in global temperatures. Records of interglacial climates are similarly required to understand the influence of long-term Australian climates on biota, including past extinction events, as well as long-term (~200 thousand year; kyr) patterns in Australian climate drivers. However, records of Australian palaeoclimates beyond the Last Glacial Maximum (~20 ± 2 thousand years ago; ka) are rare, limiting detailed analysis of long-term climate patterns and associated responses. This thesis presents a review of Australian climate records beyond the last glacial stage and a new late-Quaternary multi-proxy climate record from Fern Gully Lagoon, North Stradbroke Island (Minjerribah), through the following components: • A review and synthesis of hydroclimate data from 40 Australian marine isotope stage 3 (MIS 3; 57 – 29 ka) records, allowing a continental record of moisture availability to be created, and moisture availability during peak Australian megafauna extinction to be identified (Chapter 2). • A chronology for a new wetland sediment record from subtropical Fern Gully Lagoon, using radiocarbon (14C) and optically stimulated luminescence age determination as well as estimated hiatus locations as priors for Bayesian agedepth modelling (Chapter 3). • Scanning micro-X-ray fluorescence geochemical analysis of Fern Gully Lagoon sediments, enabling a record of inorganic dust flux to be created and regional moisture availability for subtropical eastern Australia to be inferred for the past ~210 kyr (Chapter 3). • Pollen, stable carbon isotope and lipid biomarker records as indicators of wetland vegetation assemblages during recent interglacial complexes and the Holocene, allowing reconstruction of relative moisture availability, changes in fire frequency and approximate mean annual air temperatures (Chapters 4 and 5). Relatively high average Australian moisture availability for mid-MIS 3 indicates that continental climate change is unlikely to be a major driver of Australian megafauna extinction. As such, human impact rather than climate change is more likely to have driven peak megafauna loss at ~45 ka. Fern Gully Lagoon records of aeolian flux, indicative of wind deflation, provide a record from which regional moisture availability can be inferred. Regional (pollen and charcoal) and local (stable carbon isotope and lipid biomarker) climate records were then used to refine the overall multi-proxy record, as well as determine changes in regional temperatures, fire regimes and local wetland evaporation. Along with findings related to vegetation succession and climate proxy recovery methods, the multi-proxy record indicated relatively similar moisture availability at Fern Gully Lagoon during MIS 7a–c and early MIS 5, but notably drier climates during the Holocene. The Fern Gully Lagoon palaeoclimate record supports an interpretation of drier Holocene climates in subtropical Australia compared to recent interglacials, with increasing El Niño – Southern Oscillation variability a possible cause. As such, this study indicates that records of Australian climates during recent interglacials provide invaluable analogues of possible future climates not available during the Holocene.
Open Access
24-7 Safety Climate: Developing a Brief 24-ltem, Seven Dimension Measure of Work Safety Climate for Monitoring and Remediating Safety Concerns
(2022) Summers, Denvar; Kirby, Neil; Harries, Julia; School of Psychology
This thesis aimed to develop a brief multi-dimensional, cross-industry work safety climate measure that could be used for regular monitoring, but that was also comprehensive enough for identifying and remediating safety concerns. Use of such a brief measure could contribute to reducing the human and financial costs of safety accidents, with the extensive length of many safety climate measures considered a barrier to regular use. A literature review suggested that the most efficient way to develop a brief measure involved shortening an existing reliable, valid and comprehensive cross-industry work safety climate measure. After a rigorous review of measures, the 50-item, 7-dimension Nordic Occupational Safety Climate Questionnaire (NOSACQ-50; Kines et al., 2011) was selected as a basis for the brief measure. Study one examined the NOSACQ-50 reduction using statistical and additional practical usefulness methods (i.e., item readability, item importance rankings from safety researchers and practitioners). NOSACQ-50 data from disability support (N = 366) and hospitality workers (N = 111) were used for statistical reduction methods. Expert opinions and importance rankings were collected from safety researchers (N = 5) and practitioners (N = 14). Statistical and practical usefulness findings were combined to derive a 24-item NOSACQ (NOSACQ-24). The NOSACQ-50 diagnostic value and dimensional structure were maintained to enable use of existing safety climate benchmarks and for use of the NOSACQ-50 when more comprehensive evaluation was indicated. Study two investigated the NOSACQ-24 construct, external, and concurrent validity; measurement equivalence; and benchmarking capabilities. Confirmatory factor analysis (CFA) was performed to confirm model fit using disability support and hospitality workers (N = 474) NOSACQ responses. External validity was established using responses from casual workers (N = 120) and vocational education and training (VET) workers (N = 53). Results further supported the NOSACQ-24 validity. Study three extended the NOSACQ-24 validity investigations and examined acuity for identifying safety subcultures associated with various demographic and job-related variables. NOSACQ-24 responses from VET workers (N = 549) were utilised, with safety climate subcultural differences demonstrated for managerial function, work-type, workplace location, employment status, and gender. Thus, the NOSACQ-24 retained the NOSACQ-50’s capacity to identify subcultural differences offering further support for the validity and practical usefulness of the NOSACQ-24. Study four sought to develop a 4-item supplementary measure to accompany the NOSACQ-24 to identify organisational change capability issues that might impede successful safety intervention implementation. These items were derived from research evidence associated with factors facilitating or hindering organisational change and included: overall change capability, overt top management support, use of champions of change, and worker buy-in. Mixed methodology was employed to validate the measure using qualitative and quantitative responses from VET workers (N= 485). Results provided initial support for the change capability measure and suggested that with further validation and development, the combination of the NOSACQ-24 and 4-item change capability measure could be a useful practical measure for identifying safety concerns requiring remediation and for providing a measure of an organisation’s ability to successfully implement change, thus reducing the high failure rate of change interventions reported in the research literature.
Open Access
28 / Christopher Lappas.
(2005) Lappas, Christopher; School of Humanities : English
Open Access
2D lithospheric imaging of the Delamerian and Lachlan Orogens, southwestern Victoria, Australia from Broadband Magnetotellurics
(2016) Merrett, H. D.; School of Physical Sciences
A geophysical study utilising the method of magnetotellurics (MT) was carried out across southwestern Victoria, Australia, imaging the electrical resistivity structure of the lithosphere beneath the Delamerian and Lachlan Orogens. Broadband MT (0.001-1000 Hz) data were collected along a 160 km west-southwest to east-northeast transect adjacent to crustal seismic profiling. Phase tensor analyses from MT responses reveal a distinct change in electrical resistivity structure and continuation further southwards of the Glenelg and Grampians-Stavely geological zones defined by the Yarramyljup Fault, marking the western limit of exploration interest for the Stavely Copper Porphyries. The Stawell and Bendigo Zones also show change across the Moyston and Avoca faults, respectively. Results of 2D modelling reveal a more conductive lower crust (10-30 Ωm) and upper mantle beneath the Lachlan Orogen compared to the Delamerian Orogen. This significant resistivity gradient coincides with the Mortlake discontinuity and location of the Moyston fault. Broad-scale fluid alteration zones were observed through joint analysis with seismic profiling, leaving behind a signature of low-reflectivity, correlating to higher conductivities of the altered host rocks. Isotopic analysis of xenoliths from western Victoria reveal the lithospheric mantle has undergone discrete episodes of modal metasomatism. This may relate to near-surface Devonian granite intrusions constrained to the Lachlan Orogen where we attribute the mid to lower crustal conductivity anomaly (below the Stawell Zone) as fossil metasomatised ascent paths of these granitic melts. This conductivity enhancement may have served to overprint an already conductive lithosphere, enriched in hydrogen from subduction related processes during the Cambrian. A predominately reflective upper crust exhibits high resistivity owing to turbidite and metasedimentary rock sequences of the Lachlan Orogen, representative of low porosity and permeability. Conductive sediments of the Otway Basin have also been imaged down to 3 km depth southwest of Hamilton.
Open Access
3 dimensional flow and thermal modelling of the friction stir welding process
(2001) Colegrove, Paul; Painter, Mike; Graham, Denny; Wahab, M. A.; School of Chemical Engineering & Advanced Materials
Friction Stir V/elding (FSW) is a relatively new welding process, having being patented in 1991 by The Welding Institute, Cambridge. This process has great advantages in welding difficult to weld aluminium alloys. The process gives low post weld distortion, can weld thick sections in a single pass and produces welds with excellent mechanical properties. FS'W uses a rotating tool to generate heat by mechanical work and friction. A key feature of the process is the localised deformation and material flow around the FSW tool. Various authors have used analytical and numerical thermal models to predict the weld microstructure and residual stress and distortion. However these models have not yet been able to predict the conditions whereby a successful weld can be achieved. To fully understand the complete welding process flow modelling is required. Some preliminary flow models have been published, however the field is still largely in its infancy. Therefore, this thesis presents: o A thorough review of the thermal models that have been published to date. o A brief investigation into the related field of friction welding. o An investigation into the material properties that will be relevant to the process. o A theory for describing how the material flows around the pin. This is an area that is not fully understood and is necessary to the development of a successful flow model of the process. The work reviews the current literature in this area as well as presenting some new data to support the proposed theory. A theory for analysing the heat generated around the pin. This has been used in the thermal model described below. A basic thermal model of the process. This model is quasi-steady state and is solved using the finite element method. Features of this model are the inclusion of the tool and backing plate, and the inclusion of heat generation at the pin, which is particularly relevant to the welding of thick sections. This model has been validated for a weld with 12mm thick 5083 aluminium. The development of transient thermal models for thick plate aluminium. These models have shown how transient effects at the plate ends and the duration of the initial plunge have a drastic impact on the resulting thermal profile. 25mmthick 5083,7150 and a 1000 series aluminium alloy have been used in this modelling work. The development of an automatic meshing program for use in a finite element model for solving the flow around the pin. Two finite element packages have been used to predict the flow of material around the pin. The model is isothermal and has not included the effect of any slip between the tool and the workpiece material. This model is able to show the amount of heat generated, and the pressure and flow of material around the pin. An investigation into the microstructure produced from a 5083 Friction Stir Weld. This microstructure demonstrated stick slip flow around the pin through analysing the 'so-called' pin retraction defect. The flow features observed in the weld were compared against the weld travel and rotational An investigation into the evidence for and against surface melting during Friction Stir Welding. While microstructural evidence indicates that surface melting does not occur, some temperature measurements suggest otherwise. A balanced review is presented. It is believed that more data is required for a definitive answer. It is believed that the thesis lays the foundations for future thermal and flow modelling of the friction stir welding process.
Open Access
A 3-D gravity and aeromagnetic interpretation of the Black Hill-Cambrai region
(1989) Kennedy, R. J.; School of Physical Sciences
The western edge of the Murray Basin overlies Kanmantoo sediments and contains anomalously high and low Bouger Gravity values. From available geological information, the anomalies are due to acidic intrusions, basic intrusions, and thickening of Tertiary sediments. A steeply flanked regional anomaly exists within the area. The anomaly is positive, 50 kilometres wide and has an amplitude of 25 mgals. This feature was modelled as a lopolith 5 kilometres thick with a feeder system extending to 30 km. Previous work in the Black Hill-Cambrai area had been mainly qualitative in nature. Considerable time was needed in order to tie three previous surveys together and form a reliable database. This database was incorporated in the thesis, and further work was done to increase the coverage of the anomaly. Gravity and magnetics results reveal the possibility of three basic intrusions that may be related at depth by a system of dykes. Two of the bodies, which are known as Cambrai and Black Hill, were studied in close detail. The regional gravity gradient needed to be removed and has been done so through the application of polynomial fitting with geological constraints. Attempts were made to define the shape and depth extent of the structures by means of 3-D modelling. It was revealed that the anomalies were possibly due to plumes of basic material with inward dipping walls and also a circular feeder system. Dykes occur around the basic bodies, possibly associated with the feeder system, indicating an extensional regime existed at the time of the intrusions.
Open Access
A 3-D seismic interpretation of the Palaeo-Fluvial geomorphology of the off-shore Gippsland Basin utilising seismic attibutes
(2015) Neden, Luke; Bunch, Mark; Australian School of Petroleum
The stratigraphy of the offshore Gippsland Basin exhibits extensive channelization features which developed during periods of lowstand that lowered base level causing incision and sediment bypass. These features are well documented at shallow depths but deeper in the stratigraphy the extent and geometry are less well defined. Traditional structural traps in the basin are becoming depleted and these features represent possible new targets. Equally their presence where down-cut into sealing lithologies represent a risk to the seal integrity/capacity overlying potential reservoirs concerned with CO2 storage. Seismic attributes, specifically coherence (variance) and sweetness, are co-rendered and mapped on stratal slices of the Gippsland Megasurvey 3D seismic dataset to enhance seismic images and establish the extent and geometry of channelisation in the offshore Gippsland Basin. These findings may help to identify new targets and determine potential for greenhouse gas storage, as well as helping to account for seismic anomalies that have been responsible for the misplacement of drilling targets in the past.
Open Access
3D Bioprinting of Advanced Bioinks for Tissue Engineering Applications
(2021) Rastin, Hadi; Losic, Dusan; Tung, Tran Thanh; School of Chemical Engineering
Organ transplantation would be the first option for those whose tissues/organs have been extremely injured. However, the growing gap between the number of organ donors and receivers has resulted in the long waiting list for organ transplantation. Regenerative medicine has emerged as a promising approach to tackle the crisis associated with organ shortage by employing the principle of engineering and biology. The regenerative medicine aims to support and accelerate the regeneration of defective tissue/organs through combining cells, scaffolds, and growth factors. Among various biofabrication methods, tremendous attention has been devoted to the recently emerged three-dimensional (3D) bioprinting technology for the fabrication of functional tissue-engineered scaffold loaded with cells due to its ability to assemble complex structures with meticulous control over the entire fabrication process. It is a computer-assisted technology that enables the direct fabrication of complex 3D constructs usually layers upon layers fashion according to a pre-designed structure. The 3D bioprinting concept was borrowed from 3D printing technology that has been primarily exploited in fabrication industries as a rapid prototyping technology. Harnessing the 3D printing technology in the generation of personalized implants, tissue-engineered scaffolds, drug delivery devices, tissue models has opened up a new avenue for the biofabrication methods. For bioprinting application, an ideal bioink should possess a set of desirable properties including biodegradability, biocompatibility, providing mechanical strength and rheological properties, and closely mimicking the native tissue microenvironment. The selection of materials to be used as bioinks remains the main bottleneck in the realization of 3D bioprinting technology. This thesis aims to develop novel bioinks to address the challenges associated with current bioinks by employing polymers and nanomaterials. The specific objectives of this thesis are organized into seven chapters that will be presented in the form of a collection of the published papers which are the results of the research. In addition, a literature review has been provided to establish the background of this research. Overall, the main contributions of this thesis to the 3D bioprinting field are as follows: ➢ Development of a novel bioink composed of methylcellulose/gelatin-methacryloyl (MC/GelMA) hydrogel with high shape integrity and improved biological stability (paper 1). ➢ Extending the usage territory of MXene nanosheets to the 3D bioprinting field owing to its favorable features (paper 2).➢ Addressing the poor electrical conductivity of current bioinks by employing poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) conductive polymer for neural tissue engineering (paper 3). ➢ Development of bioink with potent antibacterial activity toward Gram-positive (S. aureus) and Gram-negative (P. aeruginosa) bacterial, while supporting the cellular functions (paper 4).
Open Access
3D Bioprinting of Hybrid Biopolymer Bioinks for Wound Healing Applications
(2025) Le, Phuong Hien; Losic, Dusan; Tran, Tung; Hassan, Kamrul; School of Chemical Engineering
Chronic wounds have become a global epidemic, affecting millions of patients and contributing to high mortality rates. Among the diverse treatment approaches, 3D bioprinting has emerged as a transformative technology, offering unprecedented potential to fabricate biomimetic skin constructs with intricate cellular compositions and develop wound patches enriched with stem cells or bioactive agents to enhance wound healing. Carboxymethyl cellulose (CMC), a water-soluble cellulose derivative, has gained recognition as a promising biomaterial for 3D bioprinting due to its shear-thinning properties, structural stability across varying pH levels, exceptional water absorption capacity, and ability to provide a 3D microenvironment conducive to cellular activities. However, the limited stability of CMC-based constructs necessitates further optimization to unlock its full potential. This thesis introduces and explores several novel hybrid CMC-based bioinks tailored for wound healing applications. First, a multicomponent bioink combining CMC with xanthan gum (XG) and hyaluronic acid (HA) was formulated to harness the printability of CMC and XG alongside the cellular support properties of HA. Ionic crosslinking using ferric ions enhanced the mechanical strength and long-term stability of the printed constructs. The encapsulation of HaCaT cells and human foreskin fibroblasts within the iron-crosslinked bioinks demonstrated excellent cell viability (>95%) and preserved morphology, highlighting the efficacy of this approach in advancing hydrogel-based bioinks for soft tissue engineering. To address critical challenges, including poor electrical conductivity and inadequate antibacterial properties, a second innovation incorporated the conductive polymer poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) into a CMC-alginate (ALG) bioink network. Crosslinking with gallium ions (Ga³⁺) conferred both long-term stability and potent antibacterial properties. The resulting bioinks exhibited excellent rheological properties, biocompatibility, and electroconductivity. Moreover, when combined with electrical stimulation, these bioinks facilitated fibroblast elongation and proliferation, presenting a groundbreaking method to accelerate wound healing. These findings establish hybrid CMC-based bioinks as a versatile platform for advanced wound healing applications, bridging the gap between 3D bioprinting innovations and clinical implementation.
Open Access
A 3D CT analysis of Malay cleft lip and palate infants.
(2004) Rajion, Zainul Ahmad; Townsend, Grant Clement; Netherway, David John; Abbott, Amanda Helen; Shuaib, Ibrahim Lutfi; School of Dentistry
This thesis describes the three-dimensional (3D) assessment of craniofacial structures in cleft lip and palate patients pre-operatively. The study subjects were 29 cleft lip and palate (CLP) infants of Malay origin aged between 0-12 months and 12 non-cleft (NC) infants matched for age. CT scans were obtained using a GE Lightspeed Plus Scanner. The cranio-cervical facial morphology of cleft lip and palate has been analysed using computer programs based on cephalometric landmark points in three-dimensions. Analysis of selected craniofacial and cervical regions has included: - Measurement of the position of the hyoid bone in relation to the cervical vertebrae and cranial base - Measurement of the length of the cervical spine and intervertebral spaces - Measurement of the nasopharyngeal complex - Measurement of the cranial base - Measurement of the width of spheno-occipital synchondrosis. These findings have also been associated with related clinical problems, such as aspiration pneumonia. A statistical comparison of individual cranio-cervical facial bones of cleft lip and palate infants with age-matched adjusted for the effect of sex non-cleft infants revealed areas of significant variation from normal. Very few of the study variables displayed significant differences between males and females in either the CLP or NC group. From the analyses of these areas, findings are documented and compared to those previously reported in the literature. Furthermore, previously unreported findings have been highlighted. The anomalies noted include a lower position of the hyoid bone, located at the level of C3 or C4 in the cleft lip and palate infants, whereas in the non-cleft infants, it was positioned at the much higher level of C2 or C3. In addition, 5 patients in the cleft group had significant hyoid bone abnormalities such as absent body, greater horn or overall abnormal shape. These results could be associated with compromised function of the epiglottis in forming a seal with the larynx, thereby increasing the risk of aspiration pneumonia. The findings of the cervical spine include the significantly smaller height of the vertebral bodies with larger intervertebral spaces in the cleft lip and palate infants compared with the non-cleft infants and fusion of the posterior arch of the cervical spine. The results also showed an increased pharyngeal width in the cleft lip and palate infants compared with the non-cleft infants. These anatomical variations may be associated with disruptions in the dilatory mechanism of the eustachian tube thus leading to recurrent middle ear infection in the cleft children and subsequent loss of hearing. Analysis of data on the cranial base showed a smaller cranial base that could be associated with the observed midface hypoplasia in cleft lip and palate infants that occurs with growth in these infants. Infants with cleft lip and palate had a wider spheno-occipital synchondrosis, in contrast to the narrower spheno-occipital synchondrosis reported previously with Crouzon syndrome and Apert syndrome. A wider spheno-occipital synchondrosis could be associated with dysmorphic and compensatory growth changes in later life. The observed morphological aberrations in early childhood reflect abnormalities that have developed in embryonic/foetal life. Interestingly, the isolated cleft palate group showed different results for several study variables from the other affected groups and this is consistent with its distinct aetiology. The detailed analysis of the severity and extent of the deformities provided insight into the biological basis of cleft lip and palate. The investigation has highlighted the existence of a greater range of extracranial anomalies in cleft lip and palate than previously thought and should assist clinicians in the management of affected infants. The findings should also be of interest to craniofacial developmental biologists who are investigating the complex biological processes of human development. Furthermore, the thesis provides support for the concept that cleft lip and palate is part of a broader craniofacial anomaly, not just a localised defect.
Open Access
A 3D CT volumetric analysis of the maxillary sinuses of individuals with cleft lip and palate / Ian Scott Smith.
(2006) Smith, Ian Scott.; School of Dentistry (Orthodontics)
Open Access
The 3D electrical structure of the Australian lithosphere
(2013) May, A. J.; School of Physical Sciences
The broad-scale electrical resistivity structure of the Australian continent is poorly known due to the lack of continent-wide observations. These observations are used to constrain lithospheric conduction and petrophysical conditions. In this study, models of electrical resistivity are developed using various constraints, and these are tested against known observations. Three approaches have been employed. Firstly, using the AWAGS array of 58 magnetotelluric sites across Australia spaced approximately 500 km apart, I analyse geomagnetic depth sounding induction vector data, which are then compared with the broad-scale tectonic components of Australia. Secondly, I have developed an upper crustal and surrounding ocean model of electrical conductance using ocean depth information (ETOPO1) and depth to Proterozoic basement (SEEBASE) with a spatial resolution of approximately 17 km. Thirdly, estimates of seismic shear wave velocity of the lithosphere from 50 to 200 km depth from the AuSREM data, at a spatial resolution of approximately 50 km, were converted to electrical resistivity using an empirical relationship. The induction vectors were then compared with three dimensional modelling developed through two approaches. To good approximation I have been able to demonstrate, that the observed AWAGS induction vector data are explained to first order by the conduction of the oceans and sedimentary basins. Second-order effects of resistivity variations in the deeper lithosphere are significant, but induction vectors are less sensitive to these. Finally, I demonstrate from a 3D inversion of the observed AWAGS data that there are additional crustal conductors that cannot be explained from sediment thickness alone, but require additional conduction mechanisms in the crust over significant depths.
Open Access
3D laser scanning of dental impressions / Matthew Athanassiadis.
(2006) Athanassiadis, Matthew; School of Dentistry
This research found that laser scanning of dental impressions using a split-impression technique is possible. It also found that here is no statistical difference between the four methods of representing dental arches. Therefore, plaster models, laser-scanned plaster models, combined laser-scanned half-impressions and CT-scanned full impressions are equivalent methods for representing dental arches. --p. 103.

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