Electrochemical studies of organic compounds in zinc electrowinning circuits
- Authors: Vawdrey, Peter
- Date: 1986
- Type: Text , Thesis , Masters
- Full Text:
- Description: Most of Australia's zinc production is by the electrolytic zinc process, in which zinc is electrowon from an acid sulphate solution. The process is known to be exceptionally sensitive to the presence of trace impurities. At the Electrolytic Zinc plant (Risdon, Tasmania), isobenzofuranone (pthalide) has been detected in the electrowinning circuit, and found in higher concentrations during efficiency slumps. It was found that di-2-ethylhexyphthalate, (present in the liners and plastics used in the electrowinning circuit), is reduced to isobenzofuranone under the electrolysis conditions employed. In addition, an investigation involved a constant current electrolysis of a synthetic zinc electrolyte, as identified an additional pathway for the productionof isobenzofuranone. 2-Naphthol, added to the electrolysis circuit for current efficiency purposes, is also a major precursor of isobenzofuranone. 2-Napthol and possibly 1-nitroso-2-napthol can be oxidized to pthalic acid, either at a lead anode or via anode oxidation productions, and the phthalic acid produced can be reduced to isobenzofuranone at a zinc cathode. In addition, it was found that isobenzofurane is further reduced at the potential of zinc deposition to ultimately yield 2-methylbenzaldehyde. This compound, which has also been detected in Risdon plant electrolytes, is also toxic in the zince electrowinning circuit. The compound 2-methylabenzyl alcohol has also been detected via GLC examination of Risdon plant liquors. However, this compound was not detected in the present investigation, and thus no explanation can be offered for its presence in plant electrolytes. The toxicity of zinc electrolyte impurities on current efficiency was determined by a cyclic voltammetric technique. The results of this investigation indicate that the presence of isobenzofuranone and 2-methylbenzaldehyde can significantly lower current effciency, and the compounds phthalic acid and 2-methylbenzyl alcohol also lower efficiency.
- Description: Masters Degree in Applied Science
- Authors: Vawdrey, Peter
- Date: 1986
- Type: Text , Thesis , Masters
- Full Text:
- Description: Most of Australia's zinc production is by the electrolytic zinc process, in which zinc is electrowon from an acid sulphate solution. The process is known to be exceptionally sensitive to the presence of trace impurities. At the Electrolytic Zinc plant (Risdon, Tasmania), isobenzofuranone (pthalide) has been detected in the electrowinning circuit, and found in higher concentrations during efficiency slumps. It was found that di-2-ethylhexyphthalate, (present in the liners and plastics used in the electrowinning circuit), is reduced to isobenzofuranone under the electrolysis conditions employed. In addition, an investigation involved a constant current electrolysis of a synthetic zinc electrolyte, as identified an additional pathway for the productionof isobenzofuranone. 2-Naphthol, added to the electrolysis circuit for current efficiency purposes, is also a major precursor of isobenzofuranone. 2-Napthol and possibly 1-nitroso-2-napthol can be oxidized to pthalic acid, either at a lead anode or via anode oxidation productions, and the phthalic acid produced can be reduced to isobenzofuranone at a zinc cathode. In addition, it was found that isobenzofurane is further reduced at the potential of zinc deposition to ultimately yield 2-methylbenzaldehyde. This compound, which has also been detected in Risdon plant electrolytes, is also toxic in the zince electrowinning circuit. The compound 2-methylabenzyl alcohol has also been detected via GLC examination of Risdon plant liquors. However, this compound was not detected in the present investigation, and thus no explanation can be offered for its presence in plant electrolytes. The toxicity of zinc electrolyte impurities on current efficiency was determined by a cyclic voltammetric technique. The results of this investigation indicate that the presence of isobenzofuranone and 2-methylbenzaldehyde can significantly lower current effciency, and the compounds phthalic acid and 2-methylbenzyl alcohol also lower efficiency.
- Description: Masters Degree in Applied Science
Physiological responses of adult males to regular exercise
- Authors: Hopley, Brian
- Date: 1983
- Type: Text , Thesis , Masters
- Full Text:
- Description: "The purpose of this investigation was to determine the comparative effects of training by jogging, circuit weight training, swimming and calisthenic/endurance games on middle-aged men."
- Description: Thesis (Master of Applied Science)
- Authors: Hopley, Brian
- Date: 1983
- Type: Text , Thesis , Masters
- Full Text:
- Description: "The purpose of this investigation was to determine the comparative effects of training by jogging, circuit weight training, swimming and calisthenic/endurance games on middle-aged men."
- Description: Thesis (Master of Applied Science)
A study of sulphur xanthates in relation to their role in froth flotation of sulphide minerals
- Authors: Honeyman, Ronald
- Date: 1980
- Type: Text , Thesis , Masters
- Full Text: false
- Description: Potassium alkyl xanthates are commonly used as collectors in the flotation of sulphide minerals. Much research has been directed to the formulation of mechanisms responsible for the hydrophobicity of the sulphide minerals in xanthate flotation. Alkyl dixanthogen plays an important role in this mixed-potential mechanism, and is regarded as the species which imparts hydrophobicity to the mineral surface. Winter has recently suggested that sulphur xanthates, which are chemically very similar to alkyl dixanthogen, may play a significant role in the processes rendering the sulphide minerals hydrophobic during froth flotation. The aim of this investigation was to develop techniques for the separation and identification of sulphur xanthates at very low levels of conecentration. Techniques employed were Molecular Emission Cavity Analysis Spectroscopy and High Performance Liquid Chromatography. It was possible to extract the sulpur xanthates from simulated flotation liquors, separate the individual species, and determine them to a level of 0.05 ppm in the liquor. Aklyl sulphur dixanthates were found to disproportionate in methanol solution.
- Description: Masters Degree in Applied Science
- Authors: Honeyman, Ronald
- Date: 1980
- Type: Text , Thesis , Masters
- Full Text: false
- Description: Potassium alkyl xanthates are commonly used as collectors in the flotation of sulphide minerals. Much research has been directed to the formulation of mechanisms responsible for the hydrophobicity of the sulphide minerals in xanthate flotation. Alkyl dixanthogen plays an important role in this mixed-potential mechanism, and is regarded as the species which imparts hydrophobicity to the mineral surface. Winter has recently suggested that sulphur xanthates, which are chemically very similar to alkyl dixanthogen, may play a significant role in the processes rendering the sulphide minerals hydrophobic during froth flotation. The aim of this investigation was to develop techniques for the separation and identification of sulphur xanthates at very low levels of conecentration. Techniques employed were Molecular Emission Cavity Analysis Spectroscopy and High Performance Liquid Chromatography. It was possible to extract the sulpur xanthates from simulated flotation liquors, separate the individual species, and determine them to a level of 0.05 ppm in the liquor. Aklyl sulphur dixanthates were found to disproportionate in methanol solution.
- Description: Masters Degree in Applied Science
Chemistry of bis(O-ethyldithiocarbonato)cadmium(II) and flotation properties of aminodithiocarbonates
- Authors: Griffiths, Philip
- Date: 1976
- Type: Text , Thesis , Masters
- Full Text: false
- Description: Masters of Applied Science
- Authors: Griffiths, Philip
- Date: 1976
- Type: Text , Thesis , Masters
- Full Text: false
- Description: Masters of Applied Science
Movements, Behaviour and Ecology of the Brolga, Antigone rubicunda, at multiple spatial and temporal scales
- Authors: Veltheim, Inka
- Type: Thesis , PhD
- Full Text:
- Description: The study of animal movement patterns, within and between habitats, is a key consideration in ecological and evolutionary disciplines. Movement studies address: where, when, why and how animals move and what scales are movements taken at? For example: when and how animals move in response to internal factors, such as the need to breed, or external factors such as weather? Understanding animal movements is crucial in conservation planning and management of species. My thesis aim was to understand brolga (Antigone rubicunda) spatial landscape use across their south-east Australian core range at multiple scales. The information presented in this thesis can be applied for conservation and management of the species. I deployed 23 GPS transmitters on adults (5), juveniles (6) and chicks (12) and used a range of modelling approaches, location data and behavioural data to study their movements. Modelling methods included: behavioural change point analysis, kernel density analysis and Brownian bridge movement models to estimate home ranges; Maxent to build a species distribution model, parametric compositional analysis to study habitat selection; Bayesian and frequentist linear models to investigate relationships between environmental variables and movements, habitat use and behaviour; and NicheMapperTM to understand ecophysiological drivers of movement behaviour. GPS-tracking revealed two seasonal movement strategies within the south-west Victorian brolga range with individuals moving either 100 km or 20 km on average, between non-breeding and breeding areas, depending on capture location. However, I found many exceptions to a strictly seasonal pattern of movement, suggesting brolgas have a flexible and adaptable movement strategy. Brolgas adopted a migratory or resident strategy, indicating that the south-west Victorian population is partially migratory. I investigated whether a dynamic species distribution model (dSDM), built with Maxent using short-term weather variables, could predict seasonal distribution and movements of brolgas at a landscape scale. Using GPS tracking data to validate the dSDM output, I demonstrated that the dSDM was useful for modelling occupancy and seasonal distribution, but did not explicitly capture movements at the scale the movements occurred. However, brolgas moved further and occupied highest suitable habitat available when predicted habitat suitability in south-west Victoria was low, suggesting brolgas track areas with high predicted habitat suitability. Dynamic species distribution models may be useful in identifying suitable habitat when overall habitat suitability within a species’ range is low. At the home range scale, I used the Brownian bridge movement model to estimate breeding home range size and parametric compositional analysis to determine habitat use and selection by brolgas. I expected wetland size, density and number of chicks in a clutch to influence home range sizes, however, found only weak evidence for greater home ranges with increased clutch size. Brolgas used either single or multiple wetlands within their home ranges, and those using multiple wetlands either switched between wetlands or relocated permanently. Within their breeding home ranges brolgas appeared to select against buildings and watercourses but showed no selection for land use type. At the daily scale, I focused on movement behaviour of brolgas between foraging areas in cropped paddocks and wetland roosts. I used a correlative and a mechanistic model to investigate the influence of thermoregulatory constraints and weather on daily movement decisions of brolgas. Movements between the two habitats were not driven by biophysical requirements. The results suggest brolgas tolerate a range of weather conditions before shifting habitats to reduce heat stress and metabolic costs or to maintain water balance. In this thesis, I discuss the ecological and conservation implications of my research findings. Finally, I also provide recommendations for avoiding wind farm impacts on the threatened south-west Victorian brolga population given my findings on daily, seasonal and annual movement patterns. Many studies have investigated wind farm impacts on birds. However, this is one of a few that considers all lifecycle stages, and takes a multi-site and -scale approach to studying bird movements to inform conservation and wind farm planning.
- Authors: Veltheim, Inka
- Type: Thesis , PhD
- Full Text:
- Description: The study of animal movement patterns, within and between habitats, is a key consideration in ecological and evolutionary disciplines. Movement studies address: where, when, why and how animals move and what scales are movements taken at? For example: when and how animals move in response to internal factors, such as the need to breed, or external factors such as weather? Understanding animal movements is crucial in conservation planning and management of species. My thesis aim was to understand brolga (Antigone rubicunda) spatial landscape use across their south-east Australian core range at multiple scales. The information presented in this thesis can be applied for conservation and management of the species. I deployed 23 GPS transmitters on adults (5), juveniles (6) and chicks (12) and used a range of modelling approaches, location data and behavioural data to study their movements. Modelling methods included: behavioural change point analysis, kernel density analysis and Brownian bridge movement models to estimate home ranges; Maxent to build a species distribution model, parametric compositional analysis to study habitat selection; Bayesian and frequentist linear models to investigate relationships between environmental variables and movements, habitat use and behaviour; and NicheMapperTM to understand ecophysiological drivers of movement behaviour. GPS-tracking revealed two seasonal movement strategies within the south-west Victorian brolga range with individuals moving either 100 km or 20 km on average, between non-breeding and breeding areas, depending on capture location. However, I found many exceptions to a strictly seasonal pattern of movement, suggesting brolgas have a flexible and adaptable movement strategy. Brolgas adopted a migratory or resident strategy, indicating that the south-west Victorian population is partially migratory. I investigated whether a dynamic species distribution model (dSDM), built with Maxent using short-term weather variables, could predict seasonal distribution and movements of brolgas at a landscape scale. Using GPS tracking data to validate the dSDM output, I demonstrated that the dSDM was useful for modelling occupancy and seasonal distribution, but did not explicitly capture movements at the scale the movements occurred. However, brolgas moved further and occupied highest suitable habitat available when predicted habitat suitability in south-west Victoria was low, suggesting brolgas track areas with high predicted habitat suitability. Dynamic species distribution models may be useful in identifying suitable habitat when overall habitat suitability within a species’ range is low. At the home range scale, I used the Brownian bridge movement model to estimate breeding home range size and parametric compositional analysis to determine habitat use and selection by brolgas. I expected wetland size, density and number of chicks in a clutch to influence home range sizes, however, found only weak evidence for greater home ranges with increased clutch size. Brolgas used either single or multiple wetlands within their home ranges, and those using multiple wetlands either switched between wetlands or relocated permanently. Within their breeding home ranges brolgas appeared to select against buildings and watercourses but showed no selection for land use type. At the daily scale, I focused on movement behaviour of brolgas between foraging areas in cropped paddocks and wetland roosts. I used a correlative and a mechanistic model to investigate the influence of thermoregulatory constraints and weather on daily movement decisions of brolgas. Movements between the two habitats were not driven by biophysical requirements. The results suggest brolgas tolerate a range of weather conditions before shifting habitats to reduce heat stress and metabolic costs or to maintain water balance. In this thesis, I discuss the ecological and conservation implications of my research findings. Finally, I also provide recommendations for avoiding wind farm impacts on the threatened south-west Victorian brolga population given my findings on daily, seasonal and annual movement patterns. Many studies have investigated wind farm impacts on birds. However, this is one of a few that considers all lifecycle stages, and takes a multi-site and -scale approach to studying bird movements to inform conservation and wind farm planning.
Traces of the female self : exploring the documentation of women’s art through traces, impressions, residues and self-portraiture via contemporary art practice
- Authors: Janetzki, Georgia
- Type: Text , Thesis , Masters
- Full Text:
- Description: Women have always been present as artists, but not necessarily included within the canon of Western art history. Studying the canon is an accepted way of understanding the context of what has gone before, and in turn positioning ourselves within contemporary art practices and theories. However there is a disconnect when most of the individuals within the canon are nothing like us. Self-portraiture can be an embodied methodology, a starting point for an investigation that goes beyond oneself. Addressing the personal through my art practice also addresses a wider community of female artists. Through a studio-based investigation I have asked: What can visual art’s inherent capacity for generating and capturing traces, residues and impressions express in a material and conceptual way to explore self-identity and contribute to the current discourse about women artists’ history? How can these themes be visually expressed in new ways through contemporary selfportraiture, addressing absence and perspective in the documentation of women’s art? I explore these questions through experimental methods of making self-portraits. This research project considers the personal, examining representation of the self as an ontological enquiry into the roles of making and being. As a practice-led study, I pursue this line of enquiry as a means for exploring current structures of power, through a new body of work aimed at further informing Australian women’s art practice and its history.
- Description: Masters by Research
- Authors: Janetzki, Georgia
- Type: Text , Thesis , Masters
- Full Text:
- Description: Women have always been present as artists, but not necessarily included within the canon of Western art history. Studying the canon is an accepted way of understanding the context of what has gone before, and in turn positioning ourselves within contemporary art practices and theories. However there is a disconnect when most of the individuals within the canon are nothing like us. Self-portraiture can be an embodied methodology, a starting point for an investigation that goes beyond oneself. Addressing the personal through my art practice also addresses a wider community of female artists. Through a studio-based investigation I have asked: What can visual art’s inherent capacity for generating and capturing traces, residues and impressions express in a material and conceptual way to explore self-identity and contribute to the current discourse about women artists’ history? How can these themes be visually expressed in new ways through contemporary selfportraiture, addressing absence and perspective in the documentation of women’s art? I explore these questions through experimental methods of making self-portraits. This research project considers the personal, examining representation of the self as an ontological enquiry into the roles of making and being. As a practice-led study, I pursue this line of enquiry as a means for exploring current structures of power, through a new body of work aimed at further informing Australian women’s art practice and its history.
- Description: Masters by Research