Search

Oil-in-water emulsions are an important vehicles for the delivery of hydrophobic bioactive compounds into a range of food products. The preparation of very fine emulsions is of increasing interest to the beverage industry, as novel ingredients can be added with negligible impact to solution clarity. In the present study, both a batch and focused flow-through ultrasonic cell were utilized for emulsification with ultrasonic power generation at 20-24 kHz. Emulsions with a mean droplet size as low as 135±5 nm were achieved using a mixture of flaxseed oil and water in the presence of Tween 40 surfactant. Results are comparable to those for emulsions prepared with a microfluidizer operated at 100 MPa. The key to efficient ultrasonic emulsification is to determine an optimum ultrasonic energy intensity input for these systems, as excess energy input may lead to an increase in droplet size. Industrial relevance: The preparation of oil-in-water emulsions is a common feature of food processing operations. The use of ultrasound for this purpose can be competitive or even superior in terms of droplet size and energy efficiency when compared to classical rotor-stator dispersion. It may also be more practicable with respect to production cost, equipment contamination and aseptic processing than a microfluidisation approach. The present paper shows that ultrasound can be effective in producing nanoemulsions for use in a range of food ingredients.

The broad-scale distribution of fossils within Victoria is controlled by general global patterns in the biological evolution of life on Earth, the local development and environmental evolution of habitats, and the occurrence of geological processes conducive to the preservation of fossil floras and faunas. Early Palaeozoic fossils are mostly marine in origin because of the predominance of marine sedimentary rocks in Victoria and because life on land was not significant during most of this time interval. Middle Palaeozoic sequences have both terrestrial and marine fossil records. Within Victoria, marine rocks are only very minor components of strata deposited during the late Palaeozoic, so that few marine fossils are known from this time period. A similar situation existed during most of the Mesozoic except towards the end of this era when marine conditions began to prevail in the Bass Strait region. During long intervals in the Cainozoic, large areas of Victoria were flooded by shallow-marine seas, particularly in the southern basins of Bass Strait, as well as in the northwest of the State (Murray Basin). Cainozoic sediments contain an extraordinary range of animal and plant fossils. During the Quaternary, the landscape of Victoria became, and continues to be, dominated by continental environments including, at times, extensive freshwater lake systems. Fossil floras and faunas from sediments deposited in these lake systems and from other continental sediments, as well as from Quaternary sediments deposited in marginal marine environments, collectively record a history of rapid fluctuations in climate and sea level.

Conodont data from the banded mine sequence of the Cu-Au deposit shows that it is the same age as the lithostratigraphically similar banded mineralised sequence of the upper Mount Warner Volcanics in the Dee Range, 14 km to the SE, and that a single system of stratigraphic nomenclature may be used for both. The conclusion enhances the prospectivity of the relatively underexplored Mount Warner Volcanics., Conodont data from the banded mine sequence of the Cu-Au deposit shows that it is the same age as the lithostratigraphically similar banded mineralised sequence of the upper Mount Warner Volcanics in the Dee Range, 14 km to the SE, and that a single system of stratigraphic nomenclature may be used for both. The conclusion enhances the prospectivity of the relatively underexplored Mount Warner Volcanics.

A 'first pass' regional metamorphic study of the Cobar Basin is presented in this paper based on the result of a petrographic re-evaluation of secondary mineral assemblages. New information is included on the thermal maturity of the Cobar Basin based on Conodont Alteration Index (CAI) data. The differences are discussed between burial metamorphism, rift basin metamorphism, regional metamorphism, hydrothermal metamorphism and contact metamorphism. The timing is related and the distribution of metamorphic grade and the type of metamorphism to mineralisation in the Cobar field. Mineralisation in the main Cobar mining field is associated with high strain zones but importantly, hydrothermal metamorphism highs are also associated with mineral deposits in areas of comparatively lower strain (e.g. Nymagee copper mine, Hera gold mine). The established, perturbed thermal regime promoted further regional-scale epizone hydrothermal metamorphism during basin inversion, leading to further mineralisation and probable metal remobilisation to form Cobar-type mineralisation in zones of high strain. This study was conducted during the development of the Cobar Special 1:500 000 metallogenic map of Fitzherbert et al. and that mapping informs the stratigraphic interpretations used in this paper., A 'first pass' regional metamorphic study of the Cobar Basin is presented in this paper based on the result of a petrographic re-evaluation of secondary mineral assemblages. New information is included on the thermal maturity of the Cobar Basin based on Conodont Alteration Index (CAI) data. The differences are discussed between burial metamorphism, rift basin metamorphism, regional metamorphism, hydrothermal metamorphism and contact metamorphism. The timing is related and the distribution of metamorphic grade and the type of metamorphism to mineralisation in the Cobar field. Mineralisation in the main Cobar mining field is associated with high strain zones but importantly, hydrothermal metamorphism highs are also associated with mineral deposits in areas of comparatively lower strain (e.g. Nymagee copper mine, Hera gold mine). The established, perturbed thermal regime promoted further regional-scale epizone hydrothermal metamorphism during basin inversion, leading to further mineralisation and probable metal remobilisation to form Cobar-type mineralisation in zones of high strain. This study was conducted during the development of the Cobar Special 1:500 000 metallogenic map of Fitzherbert et al. and that mapping informs the stratigraphic interpretations used in this paper.