58 resultados para coal reactivity

em Deakin Research Online - Australia


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From 1847 until his death in 1899, Professor Frederick McCoy, palaeontologist in Melbourne, maintained a war of words in the scientific literature with Rev. William Clarke, geologist in Sydney, concerning the age of Australia’s black coal deposits. McCoy was convinced that the coals were all of Mesozoic age and Clarke, during the period from 1847 to his death in 1878, maintained equally vehemently that they were Palaeozoic. In fact, Clarke was correct in placing the New South Wales coals in the Palaeozoic, and McCoy’s placing of the Victorian coals in the Mesozoic was also correct. The two men were both particularly stubborn and neither would admit that they might have been arguing about coals of differing ages. Both stood unbendingly by their Northern Hemisphere, European backgrounds, and neither would change their views in the face of new evidence from the Colonies.

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The six-, eight- and twelve-membered cyclo-siloxanes, cyclo-[R2SiOSi(Ot-Bu)2O]2 (R = Me (1), Ph (2)), cyclo-(t-BuO)2Si(OSiR2)2O (R = Me (3), Ph (4)), cyclo-R2Si[OSi(Ot-Bu)2]2O (R = Me (5), Ph (6)) and cyclo-[(t-BuO)2Si(OSiMe2)2O]2 (3a) were synthesized in high yields by the reaction of (t-BuO)2Si(OH)2 and [(t-BuO)2SiOH]2O with R2SiCl2 and (R2SiCl)2O (R = Me, Ph). Compounds 1 - 6 were characterized by solution and solid-state 29Si NMR spectroscopy, electrospray mass spectrometry and osmometric molecular weight determination. The molecular structure of 4 has been determined by single crystal X-ray diffraction and features a six-membered cyclo-siloxane ring that is essentially planar. The reduction of 1 - 6 with i-Bu2AlH (DIBAL-H) led to the formation of the metastable aluminosiloxane (t-BuO)2Si(OAli-Bu2)2 (7) along with Me2SiH2 and Ph2SiH2.

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Current regulations classify fly ash as a prescribed waste and prohibit its disposal in regular landfill. Treatment of the fly ash can reduce the leach rate of metals, and allow it to be disposed in less prescribed landfill. A geopolymer matrix was investigated as a potential stabilisation method for brown coal fly ash. Precipitator fly ash was obtained from electrostatic precipitators and leached fly ash was collected from ash disposal ponds, and leaching tests were conducted on both types of geopolymer stabilised fly ashes. The ratio of fly ash to geopolymer was varied to determine the effects of different compositions on leaching rates.

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The burning of brown coal for electricity generation produces thousands of tonnes of fly ash each year. Treatment of the fly ash can reduce leach rates of metals and allow it to be disposed in less prescribed landfill. A geopolymer matrix was investigated as a potential stabilisation method for fly ash obtained from electrostatic precipitators and ash disposal ponds. The ratio of fly ash and geopolymer was varied to determine the effects of different compositions on leaching rates. The major element leachate concentrations obtained from pond ash were lower than that of precipitator fly ash. Conversely, precipitator ash-geopolymers were better for trace heavy metal stabilisation. Effective reduction of elemental concentrations in the leachate has been achieved, particularly for calcium, arsenic, selenium, strontium and barium. Scanning electron microscopy revealed the distribution of metals originated from fly ash and from added geopolymer material. It also showed that some elements are leached from ash particles to the geopolymer phase and others remained as undissolved particles. Qualitative analysis showed that fly ash particles interacted with the geopolymers phase through surface reactions.

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This study examined the relationship between personality traits implicated in the drinking literature (i.e., sensation seeking and anxiety) and reactivity to 2 different alcohol cues. The opportunity to consume alcohol was manipulated, and differences in urge and affective reactivity were assessed. Gray’s (1987) model of impulsive sensation seeking and anxiety was adopted to investigate relationships between personality and responses to the appetitive (consumption) and aversive (no consumption, nonrewarding) alcohol cues in 40 regular social drinkers. The consumption cue produced increases in appetitive motivation and positive correlations with sensation-seeking traits. The no-consumption cue produced increases in aversive motivation and positive correlations with anxiety-related traits. It was concluded that Gray’s model of impulsive sensation seeking and anxiety may provide a useful framework for examining the personality correlates of cue reactivity to different cues.

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Aims. To investigate the role of sensitivity to reward in mediating social drinkers' reactivity to alcohol cues. Design. A standard cue-reactivity paradigm was employed. Two groups of social drinkers (heavy and ight) were assessed after exposure to the sight, smell and taste of a neutral cue (water) and then an alcohol cue (glass of beer). Setting. Sessions were conducted in a laboratory based environment. Participants. Twenty heavy (12 males, eight females) and 18 light social drinkers (seven males, 11 females) were recruited; mean age was 23.6 years. Measurements. The Card Arranging Reward Responsivity Objective Test (CARROT), assessing behavioural responsiveness to a monetary incentive; urge to drink; positive affect; and the BAS scales, assessing sensitivity to reward. Findings. Heavy drinkers displayed a significant increase in responsivity to rewards (i.e. CARROT) and self-reported urge to drink, bur not positive affect, after exposure to alcohol. For the heavy drinkers, heightened sensitivity to reward (i.e. BAS scales) was significantly related to cue-elicited urge to drink and positive affect. Conclusion. The results are consistent with a conditioned appetitive motivational model of alcohol use and suggest that Gray's theory of personality may be of some benefit in explaining variation in reactivity responses.

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In this study, Australian brown coal fly ash particles have been collected from power station and analysed by scanning electron microscopy to obtain morphological information and elemental composition of individual particles. The most common particles found to be the irregular shape particle aggregates. Other shapes include ball shape with smooth surface and with some attachments; and crystal shape fine particles. The X-ray spectra of each fly ash particle revealed five groups of elemental composition, they are Si-rich particles; Ca-rich particles; Fe-rich particles; particles with Mg-Ca Matrix and particles with Si-Ca matrix. A particle sire distribution analysis has been conducted using particle size analyser and found to have a mean particle size of 21fim. The sample then was separated into fine and coarse fractions using aerodynamic classifier, and the elemental composition of both fractions were determined by ICP-AES. Borate fusion and acid dissolution method was used for sample preparation. It is found that some environmental sensitive elements such as Zn, Pb, Ni, K and Cu are enriched in fine fly ash particles. Ca has much higher contents in fine particles as well. Si and Mg have higher concentrations in coarse particles.

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Although the thermodynamic advantages of using solar energy to replace the bleed off steam in the regeneration system of Rankine cycle coal fired power stations has been proven theoretically, the practical techno/economic feasibility of the concept has yet to be confirmed relative to real power station applications. To investigate this concept further, a computer modelling software “THERMSOLV” was developed by Deakin University researchers, together with the support of the Victorian power industry and Australian Research Council (ARC). This newly developed software simulates the steam cycle to assess the techno/economic merit of the solar aided concept for various power station structures, locations and local electricity market conditions. Two case studies, one in Victoria Australia and one in Yunnan Province, China, have been carried out to show the application of the software. This paper reports the structure and functions of the software, and the results of the two case studies.

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Fly ash is generated from combustion of brown coal in power stations. The majority of fly ash is removed by electrostatic precipitators (ESP) and finally disposed into the landfill as prescribed wastes. A method was studied to add clay materials to the brown coal fly ash in order to form the so-called geopolymer network, which is effective at stopping the metal contents from leaching, and have minimum impact to the environment. The experiments were conducted parallel on leached fly ash and dry precipitator fly ash. The ratios of fly ash and added clay materials were varied to determine the effects of different compositions on leaching rates. Both X-ray diffraction analysis and scanning electron microscopy images showed that as the percentage of fly ash was increased, the formation of geopolymer is reduced. Eighteen metals and heavy metals were targeted during the leaching tests and the leachate samples were analysed using ICP-AES and ICP-MS. It was found that the reduction of metal leaching was achieved by adding up to 60% of fly ash to form the geopolymer like structure. Significant reductions were observed for calcium, strontium and barium. Leached fly ash achieved better stabilisation than dry precipitator fly ash for major elements. It's hard to quantify its effects on trace metals leaching due to their ultra low concentration in the fly ash. The samples spiked with trace metals of lead, zinc, mercury and barium showed remarkable reduction in leaching.

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We aim to support user interface designers in capturing, representing and reasoning about temporal information. We have developed a method to support user interface designers in considering how the temporal aspects of software impact the user. Importantly the method is based on a detailed analysis of data from a set of situated interviews that capture the views of practicing user interface designers. This paper discusses the background research and the motivation for the method.

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Bis(p-substituted benzoylmethyl)tellurium dibromides, (p-YC6H4COCH2)2TeBr2, (y=H (1a), Me (1b), MeO (1c)) can be prepared
either by direct insertion of elemental Te across CRf-Br bonds (where CRf refers to α-carbon of a functionalized organic moiety) or by the oxidative addition of bromine to (p-YC6H4COCH2)2Te (y = H (2a), Me (2b), MeO (2c)). Bis(p-substituted benzoylmethyl)tellurium dichlorides, (p-YC6H4COCH2)2TeCh (y = H (3a), Me (3b), MeO (3c)), are prepared by the reaction of the bis(p-substituted benzoylmethyl)tellurides 2a--c with S02Cl2, whereas the corresponding diiodides (p-YC6H4COCH2)2Teh (y = H
(4a), Me (4b), MeO (4c)) can be obtained by the metathetical reaction of la--c with KI, or alternatively, by the oxidative addition of
iodine to 2a--c. The reaction of 2a--c with allyl bromide affords the diorganotellurium dibrornides la--c, rather than the expected
triorganotelluronium bromides. Compounds 1-4 were characterized by elemental analyses, IR spectroscopy, 1H, l3C and 125Te
NMR spectroscopy (solution and solid-state) and in case of Ie also by X-ray crystallography. (p-MeOC6H4COCH2)2TeBr2 (1c) provides, a rare example, among organotellurium compounds, of a supramolecular architecture, where C-H-O hydrogen bonds appear to be the non-covalent intermolecular associative force that dominates the crystal packing.