Zircon chronochemistry of high heat-producing granites in Queensland and Europe

High heat-producing granites (HHPGs) are reservoir rocks for enhanced geothermal systems (EGS), yet the origins of their anomalous chemistry remain poorly understood. To gain a better understanding of the characteristic distribution of elemental depletions and enrichments (focussing on U, Th & K) within granite suites of different heritage and tectonic setting, and the processes that lead to these enrichments, we are undertaking a systematic accessory-mineral chronochemical study of two suites of S- and I-type granites in northern Queensland, as well as two archetypal HHPGs in Cornwall, England (S-type) and Soultz-sous- Forêts, France (I-type). Novel zircon LA-ICP-MS chronochemical methods will later be underpinned by a systematic petrographic, scanning electron microscope (SEM), and electron microprobe (EPMA) study of all the REE-Y-Th-U-rich accessory minerals to fully characterise how the composition, textural distributions and associations change with rock chemistry between and among the suites. Preliminary results indicate that zircons with inherited ages do not have anomalously high U (>1000 ppm) & Th (>400 ppm) values (Ahrens, 1965). Instead, enrichment in these HPE is seen in zircons dated to around the time of magmatic emplacement. These results indicate that enrichment arose primarily through fractional crystallisation of the granitic magmas. Our results support the suggestion that a source pre-enriched in the HPEs does not appear to be fundamental for the formation of all HHPGs. Instead fractional crystallisation processes, and the accessory minerals formed in magmas of differing initial compositions, are the key controls on the levels of enrichment observed (e.g. Champion & Chappell, 1992; Chappell & Hine, 2006). One implication is that the most fractionated granites may not be the most enriched in the HPEs and therefore prospective to future EGS development.

Application of TG-FTIR to study SO2 evolved during the thermal decomposition of coal-derived pyrite

The thermal decomposition of the coal-derived pyrite was studied using thermogravimetry combining with Fourier-transform infrared spectroscopy (TG-FTIR) techniques to gain knowledge on the SO2 gas evolution process and formation mechanism during the thermal decomposition of the coal-derived pyrite. The results showed that the thermal decomposition of the coal-derived pyrite which started at about 400 ◦C was complete at 600 ◦C; the gas evolved can be established by combining the DTG peak, the Gram–Schmidt curve and in situ FTIR spectroscopic evolved gas analysis. It can be observed from the spectra that the pyrolysis products for the sample mainly vary in quantity, but not in species. It was proposed that the oxidation of the coal-derived pyrite started at about 400 ◦C and that pyrrhotite and hematite were formed as primary products. The SO2 released by the thermal decomposition of the coal-derived pyrite mainly occurred in the first pyrolysis stage between 410 and 470 ◦C with the maximum rate at 444 ◦C. Furthermore, the SO2 gas evolution and formation mechanism during the thermal decomposition of the coal-derived pyrite has been proposed.

Negotiating teacher identities : dialogic reflections on classroom interaction in a transnational context

This study investigates the development of teacher identity in a transnational context through an analysis of the voices of sixteen preservice teachers from Hong Kong who engage in interaction with primary students in an Australian classroom. The context for this research is the school-based experience undertaken by these preservice English as a second language teachers as part of their short language immersion (SLIM) program in Brisbane, Australia. Such SLIM programs are a genre of study abroad programs which have been gaining in popularity within teacher education in Australia, attended by preservice and inservice teachers from China, Hong Kong, Korea, and other Asian countries. This research is conducted at a time when the imperative to globalise higher education provision is a strategic factor in the educational policies of both Australia and Hong Kong. In Australia, international educational services now constitute the country’s third largest export with more than 400,000 students coming to Australia to study annually. In order to maintain Australia’s current global position as the third most popular Englishspeaking study destination, the government is now focusing on sustainability and the quality of the study experience being offered to international students (Bradley Review, 2008). In Hong Kong, the government sponsors both preservice and inservice English as a second language (ESL) teachers to undertake SLIM programs in Australia and other English-speaking countries, as part of their policy of promoting high levels of English proficiency in Hong Kong classrooms. Transnational teacher education is an important issue to which this study contributes insights into the affordances and constraints of a school-based experience in the transnational context. Second language teacher education has been defined as interventions designed to develop participants’ professional knowledge. In this study, it is argued that participation in a different community of practice helps to foreground tacit theories of second language pedagogy, making them visible and open to review. Questions of pedagogy are also seen as questions of teacher identity, constituting the way that one is in the classroom. I take up a sociocultural and poststructural framework, drawing on the work of James Gee and Mikhail Bakhtin, to theorise the construction of teacher identity as emerging through dialogic relations and socially situated discursive practices. From this perspective, this study investigates whether these teachers engage with different ways of representing themselves through appropriating, adapting or rejecting Discourses prevailing in the Australian classroom. Research suggests that reflecting on dilemmas encountered as lived experiences can extend professional understandings. In this study, the participants engage in a process of dialogic reflection on their intercultural classroom interactions, examining with their peers and their lecturer/researcher selected moments of dissonance that they have faced in the unfamiliar context of an Australian primary classroom. It is argued that the recursive and multivoiced nature of this process of reflection on practice allows participants opportunities to negotiate new understandings of second language teacher identity. Dialogic learning, based on the theories of Bakhtin and Vygotsky, provides the theoretic framing not only for the process of reflection instantiated in this study, but also features in the analysis of the participants’ second language classroom practices. The research design uses a combined discourse analytic and ethnographic approach as a logic-of-inquiry to explore the dialogic relationships which these second language teachers negotiate with their students and their peers in the transnational context. In this way, through discourse analysis of their classroom talk and reflective dialogues, assisted by the analytic tools of speech genres and discourse formats, I explore the participants’ ways of doing and being second language teachers. Thus, this analysis traces the process of ideological becoming of these beginner teachers as shifts in their understandings of teacher and student identities. This study also demonstrates the potential for a nontraditional stimulated recall interview to provide dialogic scaffolding for beginner teachers to reflect productively on their practice.

Australian Aboriginal Words in English : their Origin and Meaning [First edition]

This extensive reference provides authoritative information about the history of over 400 words from Aboriginal languages, offering the fullest available information about their Aboriginal background and Australian English history. The book begins with a general history of the 250 Australian aboriginal languages, including profiles of the languages that have been most significant as sources for borrowing. The words are then grouped according to subject: birds, fish, edible flora, dwellings, etc., with each work listed in a dictionary-style entry. The book concludes by addressing how words changed in English, and discusses English words that have since been adopted into Aboriginal languages.

Low temperature response of nanostructured tungsten oxide thin films toward hydrogen and ethanol

Semiconducting metal oxide based gas sensors usually operate in the temperature range 200–500 °C. In this paper, we present a new WO3 thin film based gas sensor for H2 and C2H5OH, operating at 150 °C. Nanostructured WO3 thin films were synthesized by thermal evaporation method. The properties of the as-deposited films were modified by annealing in air at 300 °C and 400 °C. Various analytical techniques such as AFM, TEM, XPS, XRD and Raman spectroscopy have been employed to characterize their properties. A clear indication from TEM and XRD analysis is that the as-deposited WO3 films are highly amorphous and no improvement is observed in the crystallinity of the films after annealing at 300 °C. Annealing at 400 °C significantly improved the crystalline properties of the films with the formation of about 5 nm grains. The films annealed at 300 °C show no response to C2H5OH (ethanol) and a little response to H2, with maximum response obtained at 280 °C. The films annealed at 400 °C show a very good response to H2 and a moderate response to C2H5OH (ethanol) at 150 °C. XPS analysis revealed that annealing of the WO3 thin films at 400 °C produces a significant change in stoichiometry, increasing the number of oxygen vacancies in the film, which is highly beneficial for gas sensing. Our results demonstrate that gas sensors with significant performance at low operating temperatures can be obtained by annealing the WO3 films at 400 °C and optimizing the crystallinity and nanostructure of the as-deposited films.

The population dynamics of the Galapagos Flightless Cormorant Phalacrocorax harrisi in relation to sea temperature

The Flightless Cormorant Phalacrocorax harrisi is restricted to c. 400 km of the western coastline of the Galápagos archipelago coinciding with the local occurrence of seasonal upwelling of oceanic currents. Individuals frequently make more than one breeding attempt per year, usually change mates, and when juveniles are raised, females desert them to the further care of their mates who complete the rearing alone. Here we report data from a ten-year historical study of a colony stretching c.2 km along the coast-line and representing c. 12% of the total population of the species. The number of clutches laid and juveniles fledged were linked to the occurrence of cold water in off-shore foraging grounds. Most Flightless Cormorants have attachments to local stretches of coastline several hundred metres long. However, a few birds travelled many kilometres, including between colonies, sometimes over open sea. We show that males invest more in nest-building and feeding of the offspring than their mates, and we relate this to the (presumed) in-bred nature of the colony and to male and female reproductive strategies. Our data validate a published demographic model of the species (Valle 1995).

Thermogravimetric analysis of the copper silicate mineral dioptase Cu6[Si6O18]·6H2O

There have been a few studies on the thermal decomposition of dioptase Cu6[Si6O18]·6H2O. The results of these analyses are somewhat conflicting and the conclusions vary among these thermo-analytical studies. The objective of this research is to report the thermal analysis of dioptase from different origins and to show the mechanism of decomposition. Thermal decomposition occurs over a very wide temperature range from around 400 to 730 °C with the loss of water. Two additional mass loss steps are observed at around 793 and 835 °C with loss of oxygen. The infrared spectra of dioptase in the hydroxyl stretching region enables the hydrogen bond distances of water molecules in the dioptase structure to be calculated. The large variation in the hydrogen bond distances offers an explanation as to why the decomposition of dioptase with loss of water occurs over such a wide temperature range.

Contemporaneous correlations within individuals in an automated web-based walking program (Walk@Work) over a six week period (three phases) of time

Introduction: Participants may respond to phases of a workplace walking program at different rates. This study evaluated the factors that contribute to the number of steps through phases of the program. The intervention was automated through a web-based program designed to increase workday walking. Methods: The study reviewed independent variable influences throughout phases I–III. A convenience sample of university workers (n=56; 43.6±1.7 years; BMI 27.44±.2.15 kg/m2; 48 female) were recruited at worksites in Australia. These workers were given a pedometer (Yamax SW 200) and access to the website program. For analyses, step counts entered by workers into the website were downloaded and mean workday steps were compared using a seemingly unrelated regression. This model was employed to capture the contemporaneous correlation within individuals in the study across observed time periods. Results: The model predicts that the 36 subjects with complete information took an average 7460 steps in the baseline two week period. After phase I, statistically significance increases in steps (from baseline) were explained by age, working status (full or part time), occupation (academic or professional), and self reported public transport (PT) use (marginally significant). Full time workers walked more than part time workers by about 440 steps, professionals walked about 300 steps more than academics, and PT users walked about 400 steps more than non-PT users. The ability to differentiate steps after two weeks among participants suggests a differential affect of the program after only two weeks. On average participants increased steps from week two to four by about 525 steps, but regular auto users had nearly 750 steps less than non-auto users at week four. The effect of age was diminished in the 4th week of observation and accounted for 34 steps per year of age. In phase III, discriminating between participants became more difficult, with only age effects differentiating their increase over baseline. The marginal effect of age by phase III compared to phase I, increased from 36 to 50, suggesting a 14 step per year increase from the 2nd to 6th week. Discussion: The findings suggest that participants responded to the program at different rates, with uniformity of effect achieved by the 6th week. Participants increased steps, however a tapering off occurred over time. Age played the most consistent role in predicting steps over the program. PT use was associated with increased step counts, while Auto use was associated with decreased step counts.

Desalination by a solar thermal membrane distillation process

A solar thermal membrane distillation pilot plant was operated for over 70 days in field conditions. The pilot plant incorporated a single spiral wound permeate gap membrane distillation style of module. All energy used to operate the unit was supplied by solar hot water collectors and photovoltaic panels. The process was able to produce a distillate stream of product water with a conductivity less than 10 µS/cm. Feed water concentration varied from 2,400 µS/cm to 106,000 µS/cm. The process is expected to find application in the production of drinking water for remote island and arid regions without the consumption of electrical energy.

The effect of testing protocol on immature bovine thoracic spine segment stiffness

Introduction. In vitro spine biomechanical testing has been central to many advances in understanding the physiology and pathology of the human spine. Owing to the difficulty in obtaining sufficient numbers of human samples to conduct these studies, animal spines have been accepted as a substitute model. However, it is difficult to compare results from different studies, as they use different preparation, testing and data collection methods. The aim of this study was to identify the effect of repeated cyclic loading on bovine spine segment stiffness. It also aimed to quantify the effect of multiple freeze-thaw sequences, as many tests would be difficult to complete in a single session [1-3]. Materials and Methods. Thoracic spines from 6-8 week old calves were used. Each spine was dissected and divided into motion segments including levels T4-T11 (n=28). These were divided into two equal groups. Each segment was potted in polymethylemethacrylate. An Instron Biaxial materials testing machine with a custom made jig was used for testing. The segments were tested in flexion/extension, lateral bending and axial rotation at 37 degrees C and 100% humidity, using moment control to a maximum plus/minus 1.75 Nm with a loading rate of 0.3 Nm per second. Group (A) were tested with continuous repeated cyclic loading for 500 cycles with data recorded at cycles 3, 5, 10, 25, 100, 200, 300, 400 and 500. Group (B) were tested with 10 load cycles after each of 5 freeze thaw sequences. Data was collected from the tenth load cycle after each sequence. Statistical analysis of the data was performed using paired samples t-tests, ANOVA and generalized estimating equations. Results. The data were confirmed as having a normal distribution. 1. There were significant reductions in mean stiffness in flexion/extension (-20%; P=0.001) and lateral bending (-17%; P=0.009) over the 500 load cycles. However, there was no statistically significant change in axial rotation (P=0.152) 2. There was no statistically significant difference between mean stiffness over the five freeze-thaw sequences in flexion/extension (p=0.879) and axial rotation (p=0.07). However, there was a significant reduction in stiffness in lateral bending (-26%; p=0.007) Conclusion. Biomechanical testing of immature bovine spine motion segments requires careful interpretation. The effect of the number of load cycles as well as the number of freeze-thaw cycles on the stiffness of the motion segments depends on the axis of main movement.

The thermal decomposition of hydronium jarosite and ammoniojarosite

The thermal decomposition of hydronium jarosite and ammoniojarosite was studied using thermogravimetric analysis and mass spectrometry, in situ synchrotron X-ray diffraction and infrared emission spectroscopy. There was no evidence for the simultaneous loss of water and sulfur dioxide during the desulfonation stage as has previously been reported for hydronium jarosite. Conversely, all hydrogen atoms are lost during the dehydration and dehydroxylation stage from 270 to 400 °C and no water, hydroxyl groups or hydronium ions persist after 400 °C. The same can be said for ammoniojarosite. The first mass loss step during the decomposition of hydronium jarosite has been assigned to the loss of the hydronium ion via protonation of the surrounding hydroxyl groups to evolve two water molecules. For ammoniojarosite, this step corresponds to the protonation of a hydroxyl group by ammonium, so that ammonia and water are liberated simultaneously. Iron(II) sulfate was identified as a possible intermediate during the decomposition of ammoniojarosite (421–521 °C) due to a redox reaction between iron(III) and the liberated ammonia during decomposition. Iron(II) ions were also confirmed with the 1,10-phenanthroline test. Iron(III) sulfate and other commonly suggested intermediates for hydronium and ammoniojarosite decomposition are not major crystalline phases; if they are formed, then they most likely exist as an amorphous phase or a different low temperature phases than usual.

Fecal indicators and bacterial pathogens in bottled water from Dhaka, Bangladesh

Forty-six bottled water samples representing 16 brands from Dhaka, Bangladesh were tested for the numbers of total coliforms, fecal indicator bacteria (i.e., thermotolerant Escherichia coli and Enterococcus spp.) and potential bacterial pathogens (i.e., Aeromonas hydrophil, Pseudomonas aeruginos, Salmonella spp., and Shigella spp.). Among the 16 brands tested, 14 (86%), ten (63%) and seven (44%) were positive for total coliforms, E. coil and Enterococcus spp., respectively. Additionally, a further nine (56%), eight (50%), six (37%), and four (25%) brands were PCR positive for A. hydrophila lip, P. aeruginosa ETA, Salmonella spp. invA, and Shigella spp. ipaH genes, respectively. The numbers of bacterial pathogens in bottled water samples ranged from 28 ± 12 to 600 ± 45 (A. hydrophila lip gene), 180 ± 40 to 900 ± 200 (Salmonella spp. invA gene), 180 ± 40 to 1,300 ± 400 (P. aeruginosa ETA gene) genomic units per L of water. Shigella spp. ipaH gene was not quantifiable. Discrepancies were observed in terms of the occurrence of fecal indicators and bacterial pathogens. No correlations were observed between fecal indicators numbers and presence/absence of A. hydrophila lip (p = 0.245), Salmonella spp. invA (p = 0.433), Shigella spp. ipaH gene (p = 0.078), and P. aeruginosa ETA (p = 0.059) genes. Our results suggest that microbiological quality of bottled waters sold in Dhaka, Bangladesh is highly variable. To protect public health, stringent quality control is recommended for the bottled water industry in Bangladesh. Key words: bottled water, fecal indicator bacteria, quantitative PCR, bacterial pathogens, public health risk.

Adsorption of reactive dye on seawater-neutralised bauxite refinery residue

This investigation has demonstrated the need for thermal treatment of seawater neutralised red mud (SWRM) in order to obtain reasonable adsorption of Reactive Blue dye 19 (RB 19). Thermal treatment results in a greater surface area, which results in an increased adsorption capacity due to more available adsorption sites. Adsorption of RB 19 has been found to be best achieved in acidic conditions using SWNRM400 (heated to 400 �C) with an adsorption capacity of 416.7 mg/g compared to 250.0 mg/g for untreated SWNRM. Kinetic studies indicate a pseudosecond-order reaction mechanism is responsible for the adsorption of RB 19 using SWNRM, which indicates adsorption occurs by electrostatic interactions.

Synthetic reevesite-like material as a visible light photocatalyst for the decontamination of water

A synthetic reevesite-like material has been shown to decolorize selected dyes and degrade phenolic contaminants photocatalytically in water when irradiated with visible light. This material can photoactively decolorize dyes such as bromophenol blue, bromocresol green, bromothymol blue, thymol blue and methyl orange in less than 15 min under visible light radiation in the absence of additional oxidizing agents. Conversely, phenolic compounds suc has phenol, p-chlorophenol and p-nitrophenol are photocat- alytically degraded in approximately 3hwith additional H2O2 when irradiated with visible light. These reactions offer potentially energy effective pathways for the removal of recalcitrant organic waste contaminants.

Thermal treatment of natural goethite : thermal transformation and physical properties

XRD (X-ray diffraction), XRF (X-ray fluorescence), TG (thermogravimetry), FT-IES (Fourier transform infrared emission spectroscopy), FESEM (field emission scanning electron microscope), TEM (transmission electron microscope) and nitrogen–adsorption–desorption analysis were used to characterize the composition and thermal evolution of the structure of natural goethite. The in situ FT-IES demonstrated the start temperature (250 °C) of the transformation of natural goethite to hematite and the thermodynamic stability of protohematite between 250 and 600 °C. The heated products showed a topotactic relationship to the original mineral based on SEM analysis. Finally, the nitrogen–adsorption–desorption isotherm provided the variation of surface area and pore size distribution as a function of temperature. The surface area displayed a remarkable increase up to 350 °C, and then decreased above this temperature. The significant increase in surface area was attributed to the formation of regularly arranged slit-shaped micropores running parallel to elongated direction of hematite microcrystal. The main pore size varied from 0.99 nm to 3.5 nm when heating temperature increases from 300 to 400 °C. The hematite derived from heating goethite possesses high surface area and favors the possible application of hematite as an adsorbent as well as catalyst carrier.