https://ogma.newcastle.edu.au/vital/access/ /manager/Index ${session.getAttribute("locale")} 5 https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:42740  600°C) lead to selective formation of a small number of lower-chlorinated pollutants, whereas reactive surfaces, as evident from literature, engender catalytic (but non-selective) appearance of a large number of higher-chlorinated and toxic chloroaryl congeners, even at temperature of less than 300°C. Results from the density functional theory (DFT) calculations indicate that, majority of the detected congeners of PCDF arise from the oxidative transformation of the parent 4,4′-DCB; i.e., not from the commonly suggested precursors of chlorinated phenols and benzenes. Our findings have significant importance to understanding the emission of PCB and PCDD/F in combustion processes.]]> Wed 24 May 2023 15:48:24 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:27704 Wed 24 Jul 2019 15:36:26 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:33723 ortho substituted PXB as a model species yields a large number of halogenat ed compounds, including monochloro- and monobromobenzene and higher halogenated benzenes and naphthalenes and derivatives of halogenated benzenes (such as 1-chloro-4-ethynylbenzene). We also detect small amounts of chlorinated and mixed halogenated dibenzofurans. The present study provides insights into the formation of several classes of halogenated and mixed-halogenated pollutants in combustion processes involving both bromine and chlorine sources, such as those of brominated flame retardants and PVC plastics.]]> Wed 12 Dec 2018 15:55:08 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:13197 2CHCl₂) group bonded to a tetrahydrophthalimide (C₆H₈(CO)₂N-) moiety. The experiments were performed on a bench type apparatus, under conditions representing both under and well-ventilated non-flaming fires. The analyses of gaseous species relied on Fourier transform infra-red spectroscopy (FTIR) and micro gas chromatography (μGC), resulting in the identification and quantification of 11 gaseous products; among them, phosgene, thiophosgene and hydrogen cyanide. Gas chromatography - quadrupole mass spectrometry (GC-QMS) was employed to analyse the condensed products and volatile organic compounds (VOC), while a GC equipped with an ion trap mass spectrometer (GC-ITMS) was used to quantify polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F). The GC-QMS analysis determined several VOC toxicants; viz., trichloroethylene, tetrachloroethylene, benzonitrile and chlorinated benzenes. At higher temperature (600 °C), the oxidation of captafol led to the formation of mono- to hepta- CDD/F congeners including the most toxic 2,3,7,8-TCDD. In addition, the experimental results were compared to those of the other two sulfenimide fungicides, captan and folpet, both of which contain the thiotrichloromethyl (-SCCl₃) moiety rather than the thiotetrachloroethyl group of captafol. It appears that the thiotetrachloroethyl group in captafol is responsible for the difference in the toxic pollutants formed, particularly influencing the distribution and yields of PCDD/F congeners. Combined with quantum chemical calculations, the results presented in this article provide an insightful understanding of fire chemistry of the sulfenimide fungicides, especially the pathways to the formation of major toxicants during the oxidative thermal decomposition of captafol.]]> Wed 11 Apr 2018 17:02:01 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:13196 -1 and 384 pg ΣTEQ-WHO₂₀₀₅ g^-1 of alpha-cypermethrin. 1-monochlorodibenzofuran was ranked as the most abundant congener. We also conducted the analyses of volatile organic compounds (VOC) attempting to identify the PCDD/F precursors by means of HRGCquadrupole mass spectrometry (QMS). The results of VOC revealed chlorobenzene, diphenyl ether, benzaldehyde, chlorotoluene, dichlorotoluene as important PCDD/F precursors.]]> Wed 11 Apr 2018 16:17:39 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:23789 p-dioxins and dibenzofurans, only isomers of chlorinated monochlorodibenzofuran (MCDF) and chlorinated dichlorodibenzofuran (DCDF) were found at low temperatures (300 to 450 °C), with 3-MCDF as the dominant congener. In our system, they appear to form in gas phase reactions involving 4-CB and singlet oxygen (¹Δ_g O₂), the latter generated on the reactor walls. The present results indicate that the combustion of 4-CB in fires will be dominated by catalytic surfaces of fly ash below 600 °C, and by gas-phase kinetics above 700 °C.]]> Wed 11 Apr 2018 16:10:06 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:18751 Wed 11 Apr 2018 15:10:45 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:13198 Wed 11 Apr 2018 12:06:37 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:9025 Wed 11 Apr 2018 10:57:30 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:21742 1Δ_g), and their propagation underpin the mechanism of oxidation of linseed oil, leading to the self-heating and formation of volatile organic species and higher molecular weight compounds. The review also discusses the role of metal complexes of cobalt, iron and manganese in catalysing the oxidative drying of linseed oil, summarising some kinetic parameters such as the rate constants of the peroxidation reactions. With respect to fire safety, the classical theory of self-ignition does not account for radical and catalytic reactions and appears to offer limited insights into the autoignition of lignocellulosic materials soaked with linseed oil. New theoretical and numerical treatments of oxidation of such materials need to be developed. The self-ignition induced by linseed oil is predicated on the presence of both a metal catalyst and a lignocellulosic substrate, and the absence of any prior thermal treatment of the oil, which destroys both peroxy radicals and singlet O₂ sensitisers. An overview of peroxyl chemistry included in the article will be useful to those working in areas of fire science, paint drying, indoor air quality, biofuels and lipid oxidation.]]> Wed 11 Apr 2018 10:16:39 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:7987 Wed 11 Apr 2018 10:05:26 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:34439 Wed 04 Sep 2019 09:55:33 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:34458 Tue 03 Sep 2019 18:22:25 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:51853 Thu 21 Sep 2023 09:40:56 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:43325 Thu 15 Sep 2022 14:43:46 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:9353 Sat 24 Mar 2018 08:36:34 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:9350 Sat 24 Mar 2018 08:36:28 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:9349 Sat 24 Mar 2018 08:36:28 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:9345 Sat 24 Mar 2018 08:36:27 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:8041 Sat 24 Mar 2018 08:35:04 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:15275 Sat 24 Mar 2018 08:24:13 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:12365 Sat 24 Mar 2018 08:18:30 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:12448 Sat 24 Mar 2018 08:17:52 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:12434 Sat 24 Mar 2018 08:15:28 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:9983 Sat 24 Mar 2018 08:14:25 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:9981 Sat 24 Mar 2018 08:14:24 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:10420 Sat 24 Mar 2018 08:12:38 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:10414 Sat 24 Mar 2018 08:12:38 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:12166 Sat 24 Mar 2018 08:12:13 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:12272 Sat 24 Mar 2018 08:10:13 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:12273 Sat 24 Mar 2018 08:10:12 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:12285 Sat 24 Mar 2018 08:10:11 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:9797 Sat 24 Mar 2018 08:10:03 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:9799 Sat 24 Mar 2018 08:10:03 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:9800 Sat 24 Mar 2018 08:10:02 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:9804 Sat 24 Mar 2018 08:10:02 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:12253 2. We demonstrate the optimization of heat treatment of antigorite, providing a benchmark of an extreme case of activation among serpentine minerals. Antigorite was investigated non-isothermally via thermogravimetry-mass spectrometry and in situ X-ray powder diffraction, its thermal reaction sequence elucidated, and reaction kinetics subsequently modeled. Based on the thermally induced structural changes, preferred content of residual hydroxyls in the dehydroxylated antigorite amounts to 10–40% of those present initially. This degree of dehydroxylation minimized the transformation of antigorite into new crystalline phases maximizing the amorphization of the new structure. The thermal reaction sequence provided both the explanation for the observed kinetic behavior and the basis for this optimization strategy. The optimal time for heat activation corresponds to ≤30 min, including the heat-up period at a rate of 30 °C min^–1 and an isothermal stage at 730 °C. This was successfully modeled using a three-dimensional phase boundary reaction model (R3), with activation energy E_a of 160 kJ mol^–1 and a frequency factor A of 5.7 ± 4.1 × 10⁵ s^–1 (5.7 × 10⁵ s^–1 for dynamic and 1.6 × 10⁵ s^–1 for static stage). This strategy translates to a fast and efficient thermal processing in an optimally sized calcining vessel. Furthermore, these results imply that activation of the more common serpentine minerals lizardite and chrysotile would be significantly faster as their dehydroxylation proceeds at lower temperatures than that of antigorite.]]> Sat 24 Mar 2018 08:08:10 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:9906 Sat 24 Mar 2018 08:07:40 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:9905 Sat 24 Mar 2018 08:07:40 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:9907 Sat 24 Mar 2018 08:07:40 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:20459 Sat 24 Mar 2018 08:06:54 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:19259 Sat 24 Mar 2018 08:06:33 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:21380 2. A simplified rate law based on the known elementary reaction mechanism provides an excellent fit to the experimental data. The rate constant, 1.34 × 10^–6 M^–1 s^–1, is thought to be of higher accuracy than those in the literature as it does not depend on the rate of parallel reaction pathways or on the rate of interphase mass transfer of gaseous reaction products. The activation energy for the simplified rate law was established to be 107 kJ mol^–1. Quantum chemistry calculations indicate that the majority of the large activation energy results from the endothermic nature of the equilibrium 2HNO₂ ⇄ NO + NO₂ + H₂O. The rate constant for the reaction between nitrate ions and nitrous acid, which inhibits HNO₂ decomposition, was also determined.]]> Sat 24 Mar 2018 08:04:59 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:17541 2). In this study, we calculate energy profiles for the sequence: reactant + HO₂ → [complex of reactants] → transition state → [complex of products] → product + H₂O₂ for methanol, ethenol (i.e., C₂H₃OH), acetaldehyde, toluene, and phenol. Rate constants are provided in the simple Arrhenius form. Reasonable agreement was obtained with the limited literature data available for acetaldehyde and toluene. Addition of HO₂ to the various distinct sites in phenol is investigated. Direct abstraction of the hydroxyl H was found to dominate over HO₂ addition to the ring. The results presented herein should be useful in modeling the lower temperature oxidation of the five compounds considered, especially at low temperature where the HO₂ is expected to exist at reactive levels.]]> Sat 24 Mar 2018 08:03:57 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:18833 Sat 24 Mar 2018 08:03:17 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:20855 Sat 24 Mar 2018 08:02:51 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:20543 Sat 24 Mar 2018 08:02:40 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:17355 Sat 24 Mar 2018 08:01:41 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:18604 Sat 24 Mar 2018 08:01:03 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:20095 Sat 24 Mar 2018 08:00:09 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:20096 Sat 24 Mar 2018 08:00:09 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:20091 Sat 24 Mar 2018 08:00:08 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:20098 −1, to minimise secondary CO₂ emissions generated from the thermal activation of serpentinite. A CO₂ penalty of about 7% yields 0.93 net tonne of available active serpentine per tonne of serpentinite feedstock. The cost for serpentinite heat activation for this practical heating strategy amounts to A$ 1.25 per tonne of available active serpentine.]]> Sat 24 Mar 2018 08:00:07 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:20094 Sat 24 Mar 2018 08:00:07 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:21073 -5, 14(±3) × 10^-5 and 17(±4) × 10^-5 mol m^-2 s^-1 for formic, acetic and DL-lactic acids, respectively. The apparent activation energies amount to 11 ± 3, 47 ± 13 and 52 ± 14 kJ mol^-1 for dissolution in formic, acetic and DL-lactic acids, respectively. These values indicate the initial diffusion limitation in the film around wollastonite particles for formic acid, and kinetic limitation for acetic and DL-lactic acids. The rates of dissolution rapidly decline for acetic and DL-lactic acids, but remain high for formic acid. The findings are altogether indicative of high performance of formic acid for extraction of Ca²⁺ for storing CO₂. Further experiments are needed to assess the recycling of formic acid to determine its overall suitability as a Ca²⁺ carrier for the weak acid process.]]> Sat 24 Mar 2018 07:59:25 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:21793 Sat 24 Mar 2018 07:59:24 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:18974 Sat 24 Mar 2018 07:58:55 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:21813 –1 exothermic, respectively. Metal catalysts decompose hydroperoxides based on the Fenton-like mechanism into alkoxyl and peroxyl radicals.]]> Sat 24 Mar 2018 07:58:40 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:19815 3CH₂F) in argon bath gas has been studied in a dielectric barrier discharge reactor at atmospheric pressure and in the absence of oxygen and nitrogen. The reaction resulted in the formation of a polymeric solid fraction and the noncrosslinked properties of this material assisted in its characterization by solution state ¹³C and ¹⁹F nuclear magnetic resonance spectroscopy. Gel permeation chromatography revealed that the polymers include low (number average molecular weight, Mn values between 900 and 3000 g mol^-1) and high (Mn approximately 60000 g mol^-1) molecular weight fractions. A detailed polymerization mechanism is proposed, based on the published literature and the findings of the current investigation.]]> Sat 24 Mar 2018 07:56:56 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:17930 Sat 24 Mar 2018 07:56:36 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:17931 Sat 24 Mar 2018 07:56:36 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:17893 – ion selective electrode. The reaction results in the formation of nitric oxide and thiocyanogen, the latter decomposing to sulfate and hydrogen cyanide in aqueous solution. The rate of consumption of ONSCN depends strongly on the concentration of SCN^– ions and is inhibited by nitric oxide. We have developed a reaction mechanism that comprises three parallel pathways for the decomposition of ONSCN. At high thiocyanate concentrations, two reaction pathways operate including a second order reaction to generate NO and (SCN)₂ and a reversible reaction between ONSCN and SCN^– producing NO and (SCN)₂^–, with the rate limiting step corresponding to the consumption of (SCN)₂^– by reaction with ONSCN. The third reaction pathway, which becomes significant at low thiocyanate concentrations, involves formation of a previously unreported species, ONOSCN, via a reaction between ONSCN and HOSCN, the latter constituting an intermediate in the hydrolysis of (SCN)₂. ONOSCN contributes to the formation of NO via homolysis of the O–NO bond and subsequent dimerization and hydrolysis of OSCN. Fitting the chemical reactions of the model to the experimental measurements, which covered a wide range of reactant concentrations, afforded estimation of all relevant kinetic parameters and provided an excellent match. The reaction mechanism developed in this contribution may be applied to predict the rates of NO formation from ONSCN during the synthesis of azo dyes, the gassing of explosive emulsions, or nitrosation reactions occurring in the human body.]]> Sat 24 Mar 2018 07:56:25 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:17963 Sat 24 Mar 2018 07:56:22 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:20583 Sat 24 Mar 2018 07:55:36 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:21245 Sat 24 Mar 2018 07:53:02 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:21318 Scenedesmus alga to the solution. Precipitation of nesquehonite occurred during both an accelerated degassing of CO₂ induced by sparging small nitrogen bubbles (representative diameter of 20 µm), and during slow degassing engendered by introducing large nitrogen bubbles (representative diameter of 5 mm). The response of the system during low rates of degassing closely approached quasi-thermodynamic predictions, which permitted an estimation of the level of supersaturation of nesquehonite, prior to the onset of precipitation. Small bubbles and CA significantly increased rates of degassing and indirectly the production of nesquehonite, as the rate of degassing can limit the precipitation process. The response of the system during rapid rates of degassing, prior to precipitation, was not entirely consistent with quasi-thermodynamic predictions. During precipitation, higher rates of degassing produced similar alkalisation and precipitation trends to that observed for lower rates of degassing. Our results agree with the formation of travertine deposits in nature, where the degassing of solutions enriched with inorganic carbon, and enhanced alkalisation by microorganisms, have been shown to influence carbonate formation. The results demonstrate a catalytic effect of CA on the rate limiting carbonate reactions, increasing CO₂ exchange between nitrogen and water, and indirectly accelerating the precipitation of carbonates for a system controlled by rate of degassing. The results of this study have applications to large-scale storage of CO₂ by mineralisation.]]> Sat 24 Mar 2018 07:52:52 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:21467 Sat 24 Mar 2018 07:52:31 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:20192 Sat 24 Mar 2018 07:51:32 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:20190 Sat 24 Mar 2018 07:51:32 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:20188 800K) with a rate constant expression of k=2.90×10-24T3.78exp-8400Tcm3molecule-1s-1. Reasonable agreement was obtained with the limited experimental data available in the literature. Addition at the four sites of the aromatic ring and abstraction of one of the C-H aromatic bonds are relatively unimportant over the temperature range studied. We also investigate the abstraction of H from the secondary C on the ethyl chain by triplet oxygen and report the associated rate expression. The results presented herein should be useful in modelling the oxidation of alkylbenzenes at lower temperatures.]]> Sat 24 Mar 2018 07:51:32 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:20193 Sat 24 Mar 2018 07:51:31 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:18537 Sat 24 Mar 2018 07:50:11 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:16044 Na–MoC₁₋ᵪ/Al₂O₃> Ce–MoC₁₋ᵪ/Al₂O₃> Co–MoC₁₋ᵪ/Al₂O₃> MoC₁₋ᵪ/Al₂O₃ while chain growth probability varied with feed composition and was enhanced by all promoters. The reaction rate data were adequately described by an Eley–Rideal model.]]> Sat 24 Mar 2018 07:50:07 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:26110 –1 (the applied voltage range was 14.1 to 15.2 kV, peak–peak). The electrical discharge was characterized and found to be a slight modification of filamentary discharge toward a diffuse discharge due to the presence of the relatively low concentration of CCl₃F and CH₄ (less than 2% each) in argon. A reaction mechanism is proposed describing the formation of gas phase, as well as polymeric products.]]> Sat 24 Mar 2018 07:39:53 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:26104 Sat 24 Mar 2018 07:39:52 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:28586 18O, δ¹³C and F¹⁴C signatures, respectively. Low and variable concentrations of magnesite, dolomite and calcite represent bedrock carbonate, which has formed during alteration of the serpentinite bedrock before mining and is characterised by moderately high δ¹⁸O, low δ¹³C and F¹⁴C, a signature typical for ‘weathering-derived’ magnesite deposits in the GSB. The carbonate fraction of deep cement samples, collected from 70 to 120 cm below the surface, representing the bulk tailings material at depth, predominantly consists of pyroaurite (Mg₆Fe₂(CO₃)(OH)₁₆·4H₂O) and, despite stable isotope signatures similar to bedrock, contains significant radiocarbon. This indicates that pyroaurite, forming under different conditions as hydromagnesite, may represent an additional trap for atmospheric CO₂ in the Woodsreef mine tailings. The distribution of carbonates and quartz, together with the absence of isotopic mixing trends between bedrock carbonate and atmospheric-derived carbonate, strongly indicates that dissolution and re-precipitation of bedrock carbonate is not a dominant process in the Woodsreef tailings. The cations for carbonate formation are instead derived from the dissolution of serpentine minerals (lizardite and chrysotile) and brucite. The internal standard method and the reference intensity method have been used with X-ray diffraction data to estimate the abundance of the two major carbonate minerals hydromagnesite and pyroaurite, respectively. Considering the formation of hydromagnesite on the outer surface of the tailings pile alone or together with formation of pyroaurite within the tailings pile we conclude that, between 1400 and 70,000 t of atmospheric CO₂ have been sequestered in the mine tailings since closure of the mine 29 a ago. Carbonation rates of 27 g C m⁻² y⁻¹ and 1330 g C m⁻² y⁻¹ are significantly higher than background rates of CO₂ uptake by chemical weathering and demonstrate the potential of passive carbonation of mine tailings as a cost and energy effective alternative for storage of CO₂ in carbonate minerals.]]> Sat 24 Mar 2018 07:37:25 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:27420 eq corresponds to 559-382 M(⁻²) for thioacetamide (TA, 15-25 °C) and 12600-5590 M(⁻²) for thiourea (TU, 15-35 °C), whereas the reaction enthalpies amount to -27.10 ± 0.05 kJ for TA and -29.30 ± 0.05 kJ for TU. Theoretical calculations via a thermochemical cycle agree well with reaction free energies from experiments, with errors of -2-4 kJ using solvation method SMD in conjunction with hybrid meta exchange-correlation functional M05-2X and high-accuracy multistep method CBS-QB3 for gas-phase calculations. The kinetic rates increase with acidity at activation energies of 54.9 (TA) and 66.1 kJ·mol(-1) (TU) for the same temperature range, confirming activation-controlled reactions. At pH 1 and below, the main decomposition pathway for the S-nitroso species leads to formation of nitric oxide.]]> Sat 24 Mar 2018 07:35:23 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:31030 4 with N2O, particularly at higher CH₄ conversions. For this purpose, key process variables, such as temperature (300 °C–550 °C) and a molar feed ratio (N₂O/CH₄ = 1, 3, and 5), were altered to establish the conditions for maximized H₂ yield. The experimental study was conducted over the Co-ZSM-5 catalyst in a fixed bed tubular reactor and then compared with the thermodynamic equilibrium compositions, where the equilibrium composition was calculated via total Gibbs free energy minimization method. The results suggest that molar feed ratio plays an important role in the overall reaction products distribution. Generally for N₂O conversions, and irrespective of N₂O/CH₄ feed ratio, the thermodynamic predictions coincide with experimental data obtained at approximately 475 °C–550 °C, indicating that the reactions are kinetically limited at lower range of temperatures. For example, theoretical calculations show that the H₂ yield is zero in presence of excess N₂O (N₂O/CH₄ = 5). However over a Co-ZSM-5 catalyst, and with a same molar feed ratio (N₂O/CH₄) of 5, the H₂ yield is initially 10% at 425 °C, while above 450 °C it drops to zero. Furthermore, H₂ yield steadily increases with temperature and with the level of CH₄ conversion for reactions limited by N₂O concentration in a reactant feed. The maximum attainable (from thermodynamic calculations and at a feed ratio of N₂O/CH₄ = 3) H₂ yield at 550 °C is 38%, whereas at same temperature and over Co-ZSM-5, the experimentally observed yield is about 19%. Carbon deposition on Co-ZSM-5 at lower temperatures and CH₄ conversion (less than 50%) was also observed. At higher temperatures and levels of CH₄ conversion (above 90%), the deposited carbon is suggested to react with N₂O to form CO₂.]]> Sat 24 Mar 2018 07:34:52 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:27674 Sat 24 Mar 2018 07:33:52 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:27130 -1 mimicking the typical flow and conversion requirements of a catalytic system designed to treat a ventilation air methane stream. In order to gain a better understanding of the interaction between H₂O and the catalyst surface, temperature-programmed desorption of water over fresh and used samples were studied, and supported by other catalyst characterization techniques such as N₂-adsorption desorption, XRD, TEM, SEM and XPS analyses. The activity measurements of the catalysts studied identify Co₃O₄ as the most active material. Co-precipitating gold particles with cobalt oxide or iron oxide do not enhance the activity of the catalyst, which is most likely due to blocking the active site of support by the gold particle. The presence of strong hydroxyl bonds on the catalyst surface is substantiated by TPD and XPS analyses, and is suggested to be responsible for the rapid deactivation of Fe₂O₃ and Au/Fe₂O₃ catalysts.]]> Sat 24 Mar 2018 07:33:03 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:30335 -1 to 13 kJ L^-1. A reaction mechanism is proposed explaining the formation of gaseous as well as polymeric products.]]> Sat 24 Mar 2018 07:31:46 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:29772 2O₃(0001) surface toward formation of phenolic EPFRs, under conditions relevant to cooling down zones of combustion systems. We show that, molecular adsorption of phenol on α-Al₂O₃(0001) entails binding energies in the range of −202 kJ/mol to −127 kJ/mol. The dehydroxylated alumina catalyzes the conversion of phenol into its phenolate moiety with a modest activation energy of 48 kJ/mol. Kinetic rate parameters, established over the temperature range of 300 to 1000 K, confirm the formation of the phenolate as the preferred pathways for the adsorption of phenol on alumina surfaces, corroborating the role of particulate matter in the cooling down zone of combustion systems in the generation of EFPRs.]]> Sat 24 Mar 2018 07:30:33 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:25335 Sat 24 Mar 2018 07:30:24 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:25623 X emissions from industrial processes. In the present study, we examined the in situ reaction of DBNBS with nitric oxide (NO), generated via the reduction of nitrite under acidic conditions at room temperature. Significant quantities of N₂ were detected during the reaction using the membrane inlet mass spectrometer (MIMS), which suggested the homolytic cleavage of the C–N bond of a diazenyl radical, formed by decomposition of a DBNBS-NO adduct is a key reaction step which occurs during trapping. Measurements by nanostructured assisted laser desorption ionization mass spectrometer (NALDI-MS) established that the primary product from the reaction was 3,4,5-trinitrobenzene sulfonate, with a molecular weight of 291.880 amu. The technique also disclosed the formation of other nitrobenzene products. The results obtained in the present study provide evidence of a new, competing reaction pathway occurring in the presence of added nitrite, whereby a nitro group is introduced in the aromatic system by coupling with a phenyl radical to yield a radical anion, which reacts readily with the electrophile N₂O₃, also present in the system.]]> Sat 24 Mar 2018 07:28:12 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:25535 Sat 24 Mar 2018 07:26:03 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:28906 −1 (applied voltage range is 13.4–14.8 kV, peak-peak). The relatively low input feed concentration of CCl₂F₂ and methane in the argon bath gas modifies the strong filamentary appearance of the pure argon discharge to a more diffuse appearance.]]> Sat 24 Mar 2018 07:25:59 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:30564 2O conversion reactions within a temperature range of 300–600°C. These reactions were examined in a fixed bed tubular reactor. ZSM-5 (Si/ Al = 15), TS-1, and amorphous silicates were used as catalyst supports for cobalt loadings. All catalysts were prepared by following standard methods and recipes. In general, cobalt loading on supports was varied between 0.78 and 5.40 wt.-% (as determined from inductively coupled plasma (ICP) analysis). ICP, temperature programmed desorption, X-ray diffraction, and N₂ adsorption/desorption isotherms were used for the characterization of prepared catalysts. Cobalt on ZSM-5 support generates weak and strong acid sites. Furthermore, for the Co-ZSM-5 catalyst, prepared by a wet deposition method, the N₂O decomposition reaction is first order with an activation energy of ~132 kJ mol⁻¹. Co²⁺ and Co³⁺ are the suggested active species for the N₂O conversions in the studied range of temperatures.]]> Sat 24 Mar 2018 07:23:55 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:24020 -1 feed rate reduces the conversion of CF₃CH₂F from 74.5% to 46.8% and increases the formation of HF from 1500µmolh^-1 to 2640µmolh^-1. The effect of methane addition on the electrical discharge and the reaction pathways are discussed.]]> Sat 24 Mar 2018 07:16:44 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:24331 p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) from their precursors. We have identified 2,6-dichlorophenol (2,6-DCPh), 2,4-dichlorophenol (2,4-DCPh), and 2,4,6-trichlorophenol (2,4,6-TriCPh), but have detected no chlorinated benzenes (CBzs). The detected chlorinated and nonchlorinated DD/Fs comprise dibenzo-p-dioxin (DD), 1- and 2-monochlorodibenzo-p-dioxin (1-, 2-MCDD), 1,6-, 1,9-, 1,3-dichlorodibenzo-p-dioxin (1,6-, 1,9-, 1,3-DCDD), 4-monochlorodibenzofuran (4-MCDF), and 4,6-dichlorodibenzofuran (4,6-DCDF) at the reaction temperatures of 350 and 400 °C. However, at a lower reaction temperature, 250 °C, we have detected no PCDD/Fs. We have demonstrated that neat silica surfaces catalyze the generation of PCDD/Fs from chlorophenols at the upper range of the catalytic formation temperature of PCDD/F. The present finding proves the generation of PCDD/Fs on particles of fly ash, even in the absence of transition metals.]]> Sat 24 Mar 2018 07:16:37 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:24806 Sat 24 Mar 2018 07:15:14 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:24904 Sat 24 Mar 2018 07:14:52 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:23773 Sat 24 Mar 2018 07:13:21 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:23823 Sat 24 Mar 2018 07:12:50 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:24114 Sat 24 Mar 2018 07:11:41 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:22300 Sat 24 Mar 2018 07:11:06 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:22299 a values based on gas phase deprotonation free energies and calculated solvation energies for chlorinated thiophenol molecules and chlorinated thiophenolate anions. Calculated pK_a values are in good agreement with limited available experimental measurements.]]> Sat 24 Mar 2018 07:11:06 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:21503 25 mol %) concentrations of potassium in the crystallisation solution; mol % is based only on K+ and NH4+. Co-recrystallised salts were characterise using X-ray diffraction (XRD), Scanning electron microscopy - energy dispersive spectroscopy (SEM-EDS), Inductively coupled plasma - optical emission spectroscopy (ICP-OES), and Thermogravimetric analyser and differential scanning calorimeter (TGA/DSC). In addition, we report concentration profiles of NO during thermal analyses of corecrystallised potassium ammonium nitrates. The results obtained from thermal decomposition of the co-recrystallised potassium ammonium nitrate salts showed decrease in production of NO. and 3-5 mol % K was the optimal concentration when compared with pure AN.]]> Mon 20 Nov 2023 15:36:38 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:18679 Mon 20 Jul 2015 17:34:13 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:36460 Mon 11 May 2020 13:20:44 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:31130 Mon 11 Mar 2019 12:07:37 AEDT ]]>