Base material characterisation of spoil piles at BMA coal mines

This project was an initiation to investigate slaking induced properties detrition of spoil pile materials with overburden pressure and time. The changes in the material properties over time are important parameters that control the behaviour and performance of the piles. The time dependent mechanical and hydraulic properties reported together with mineralogical changes. One chamber designed to apply slaking in the laboratory and geotechnical investigation conducted to fulfil the objective of this project.

Effect of organic gate dielectric material properties on interfacial charging and discharging of pentacene MIM device

The effect of material properties of an environmentally friendly, optically transparent dielectric material, polyterpenol, on the carrier transients within the pentacene-based double-layer MTM device was investigated. Polyterpenol films were RF plasma polymerised under varied process conditions, with resultant films differing in surface chemistry and morphology. Independent of type of polyterpenol, time-resolved EFISHG study of IZO/polyterpenol/pentacene/Au structures showed similar transient behaviour with carriers injected into pentacene from Au electrode only, confirming polyterpenol to be a suitable blocking layer for visualisation of single-species carrier transportation during charging and discharging under different bias conditions. Polyterpenol fabricated under higher input power show better promise due to higher chemical and thermal stability, improved uniformity, and absence of defects.

Taken for granted: Material relations between disability and codes/guidelines

This paper provides a critical examination of the taken for granted nature of the codes/guidelines used towards the creation of designed spaces, their social relations with designers, and their agency in designing for people with disabilities. We conducted case studies at three national museums in Canada where we began by questioning societal representations of disability within and through material culture through the potential of actor-network theory where non-human actors have considerable agency. Specifically, our exploration looks into how representations of disability for designing, are interpreted through mediums such as codes, standards and guidelines. We accomplish this through: deep analyses of the museums’ built environments (outdoors and indoors); interviewed curators, architects and designers involved in the creation of the spaces/displays; completed dialoguing while in motion interviews with people who have disabilities within the spaces; and analyzed available documents relating to the creation of the museums. Through analyses of our rich data set involving the mapping of codes/guidelines in their ‘representation’ of disability and their contributions in ‘fixing’ disability, this paper takes an alternative approach to designing for/with disability by aiming to question societal representations of disability within and through material culture.

Nitrification (DMPP) and urease (NBPT) inhibitors had no effect on pasture yield, nitrous oxide emissions nor nitrate leaching under irrigation in a hot-dry climate

Modern dairy farming in Australia relies on substantial inputs of fertiliser nitrogen (N) to underpin economic production. However, N lost from dairy systems represents an opportunity cost and can pose a number of environmental risks. Nitrogen cycle inhibitors can be co-applied with N fertilisers to slow the conversion of urea to NH4+ to reduce losses via volatilisation, and slow the conversion of NH4+ to NO3- to minimize leaching of NO3- and gaseous losses via nitrification and denitrification. In a field campaign in a high input ryegrass-kikuyu pasture system we compared the soil N pools, losses and pasture production between a) urea coated with the nitrification inhibitor (3,4-dimethyl pyrazole phosphate - DMPP) b) urea coated with the urease inhibitor (N-(n-butyl) thiophosphoric triamide - NBPT) and c) standard urea. There was no treatment effect (P>0.05) on soil mineral N, pasture yield, N2O flux nor leaching of NO3- cf. standard urea. We hypothesise that at our site, because gaseous losses were highly episodic (rainfall was erratic and displayed no seasonal rainfall nor soil wetting pattern) that there was a lack of coincidence of N application and conditions conducive to gaseous losses, thus the effectiveness of the inhibitor products was minimal and did not result in an increase in pasture yield. There remains a paucity of knowledge on N cycle inhibitors in relation to their effective use in field system to increase N use efficiency. Further research is required to define under what field conditions inhibitor products are effective in order to be able to provide accurate advice to managers of nitrogen in production systems.

Thermal performance of magnesium oxide wall board using numerical modelling

Fire resistance of light-gauge steel frame (LSF) walls can be enhanced by lining them with single or multiple layers of wall boards. This research is focused on the thermal per-formance of Magnesium Oxide (MgO) wall boards in comparison to the conventional gypsum plasterboards exposed to standard fire on one side. Thermal properties of MgO board and gypsum plasterboard were measured first and then used in the finite element heat transfer models of the two types of panels. The measured thermal property results show that MgO board will perform better than the gypsum plasterboards due to its higher specific heat values at elevated temperatures. However, MgO board loses 50% of its ini-tial mass at about 500 °C compared to 16% for gypsum plasterboard. The developed finite element models were validated using the fire test results of gypsum plasterboards and then used to study the thermal performance of MgO board panels. Finite element analysis re-sults show that when MgO board panels are exposed to standard fire on one side the rate of temperature rise on the ambient side is significantly reduced compared to gypsum plas-terboard. This has the potential to improve the overall thermal performance of MgO board lined LSF walls and their fire resistance levels (FRL). However, full scale fire tests are needed to confirm this. This paper presents the details of this investigation and the results.

Material characterisation and numerical modelling of gypsum plasterboards in fire

The fire resistance characteristic of LSF wall systems mainly depends on the protective linings in use, commonly gypsum plasterboards. However, unclassified boards with varying composition and more notably with ambiguous thermal properties are increasingly becoming available in the market. Therefore a study was undertaken with an aim to set minimum standards for fire protective boards used in LSF wall applications. This paper presents the details of this study based on material characterisation and finite element thermal modelling of the most commonly used fire protective board, gypsum plasterboards, to address these critical issues related to fire safety design. In the material characterisation phase of this study, thermal properties of three different gypsum plasterboards manufactured in Australia were measured, analysed and compared. Subsequently, it proposes a thermal property based “k-factor” capable of giving an overall measure of the fire performance of boards, so that it can be used in appropriately classifying fire protective boards. As it is not known how this factor relates to the overall fire performance of LSF wall systems, numerical models were also developed and used to simulate the performance of LSF walls exposed to the standard fire. Finally, a correlation between time-temperature profiles from numerical analyses and calculated k-factors was established.

Heterojunctions between amorphous and crystalline niobium oxide with enhanced photoactivity for selective aerobic oxidation of benzylamine to imine under visible light

The formation of heterojunctions between two crystals with different band gap structures, acting as a tunnel for the unidirectional transfer of photo-generated charges, is an efficient strategy to enhance photocatalytic performance in semiconductor photocatalysts. The heterojunctions may also promote the photoactivity in the visible-light-response of any surface complex catalysts by influencing the transfer of photo-generated electrons. Herein, Nb2O5 microfibers, with a high surface area of interfaces between an amorphous phase and crystalline phase, were designed and synthesised by the calcination of hydrogen-form niobate while controlling the crystallization The photoactivity of these microfibers towards selective aerobic oxidation reactions was investigated. As predicted, the Nb2O5 microfibres containing heterojunctions exhibited the highest photoactivity. This could be due to the band gap difference between the amorphous phase and the crystalline phase, which shortened the charge mobile distance and improved the efficiency.

Material matters [curators]

The exhibition material matters brings together new works by Amy Commins, Jamie Behrendorff, Grace Kevill-Davies, Zoe Knight, Ruth McConchie and Courtney Pedersen – Brisbane-based artists whose experimental practices engage with materiality in specific ways. These works explore incidental viewpoints, suspended moments, constructed environments, cultural memory and repetitive processes. The artists in the exhibition investigate the temporal in terms of making and experiencing art in various modes – installation, sculpture, video, sound and works on paper. Through these material engagements, the artists question and re-imagine ways of connecting in the contemporary world, drawing together considerations of humour, history, politics, nature and everyday life. This exhibition was part of the 2014 Brisbane Experimental Art Festival, held at the Judith Wright Centre of Contemporary Arts.

A dye-sensitized visible light photocatalyst-Bi24 O31 Cl10

The p-block semiconductors are regarded as a new family of visible-light photocatalysts because of their dispersive and anisotropic band structures as well as high chemical stability. The bismuth oxide halides belong to this family and have band structures and dispersion relations that can be engineered by modulating the stoichiometry of the halogen elements. Herein, we have developed a new visible-light photocatalyst Bi 24 O 31 Cl 10 by band engineering, which shows high dye-sensitized photocatalytic activity. Density functional theory calculations reveal that the p-block elements determine the nature of the dispersive electronic structures and narrow band gap in Bi 24 O 31 Cl 10. Bi 24 O 31 Cl 10 exhibits excellent visible-light photocatalytic activity towards the degradation of Rhodamine B, which is promoted by dye sensitization due to compatible energy levels and high electronic mobility. In addition, Bi 24 O 31 Cl 10 is also a suitable photoanode material for dye-sensitized solar cells and shows power conversion efficiency of 1.5%.

In-situ one-step hydrothermal synthesis of a lead germanate-graphene composite as a novel anode material for lithium-ion batteries

Lead germanate-graphene nanosheets (PbGeO3-GNS) composites have been prepared by an efficient one-step, in-situ hydrothermal method and were used as anode materials for Li-ion batteries (LIBs). The PbGeO3 nanowires, around 100–200 nm in diameter, are highly encapsulated in a graphene matrix. The lithiation and de-lithiation reaction mechanisms of the PbGeO3 anode during the charge-discharge processes have been investigated by X-ray diffraction and electrochemical characterization. Compared with pure PbGeO3 anode, dramatic improvements in the electrochemical performance of the composite anodes have been obtained. In the voltage window of 0.01–1.50 V, the composite anode with 20 wt.% GNS delivers a discharge capacity of 607 mAh g−1 at 100 mA g−1 after 50 cycles. Even at a high current density of 1600 mA g−1, a capacity of 406 mAh g−1 can be achieved. Therefore, the PbGeO3-GNS composite can be considered as a potential anode material for lithium ion batteries.

Generalized self-assembly of scalable two-dimensional transition metal oxide nanosheets

Two-dimensional (2D) transition metal oxide systems present exotic electronic properties and high specific surface areas, and also demonstrate promising applications ranging from electronics to energy storage. Yet, in contrast to other types of nanostructures, the question as to whether we could assemble 2D nanomaterials with an atomic thickness from molecules in a general way, which may give them some interesting properties such as those of graphene, still remains unresolved. Herein, we report a generalized and fundamental approach to molecular self-assembly synthesis of ultrathin 2D nanosheets of transition metal oxides by rationally employing lamellar reverse micelles. It is worth emphasizing that the synthesized crystallized ultrathin transition metal oxide nanosheets possess confined thickness, high specific surface area and chemically reactive facets, so that they could have promising applications in nanostructured electronics, photonics, sensors, and energy conversion and storage devices.

The oxygen migration in the apatite-type lanthanum silicate with the cation substitution

A theoretical model is proposed to determine the effects of Si substitution with Al on the oxygen diffusion in apatite-type lanthanum silicates based on density-functional theory (DFT) calculations for La10(SiO 4)4(AlO4)2O2. Substitution changes the stable configuration for excess oxygen from the split interstitial to a new cluster form with the original cluster. Al doping completely changes the migration mechanism from the interstitialcy one, which was proposed for the La9.33(SiO4)6O2 starting material, to a mechanism which contains an interstitial process. Nevertheless, the migration barrier is calculated to be 0.81 eV, which indicates small changes in oxygen conduction and is consistent with the observations. The present study indicates that the cation substitution on silicon site alone does not promise the improvement of the oxide ion conduction in the lanthanum silicate.

Position preference and diffusion path of an oxygen ion in apatite-type lanthanum silicate La9.33Si6O26: A density functional study

Using density functional theory, we investigated the position preference and diffusion mechanisms of interstitial oxygen ions in lanthanum silicate La9.33Si6O26, which is an apatite-structured oxide and a promising candidate electrolyte material for solid oxide fuel cells. The reported lanthanum vacancies were explicitly taken into account by theoretically determining their arrangement with a supercell model. The most stable structures and the formation energies of oxygen interstitials were determined for each charged state. It was found that the double-negatively charged state is stable over a wide range of the Fermi level, and that the excess oxygen ions form split interstitials with the original oxygen ions, while the neutral and the single-negatively charged states preferably form molecular oxygen. These species were found near the lanthanum vacancy site. The theoretically determined migration pathway along the c-axis essentially follows an interstitialcy mechanism. The obtained migration barrier is sensitive to the charge state, and is also affected by the lanthanum vacancy. The barrier height of the double-negatively charged state was calculated to be 0.58 eV for the model structure, which is consistent with the measured activation energy.

A novel ionic diffusion strategy to fabricate high-performance anode-supported solid oxide fuel cells (SOFCs) with proton-conducting Y-doped BaZrO3 films

A stable Y-doped BaZrO3 electrolyte film, which showed a good performance in proton-conducting SOFCs, was successfully fabricated using a novel ionic diffusion strategy.

BaZr0.8Y0.2O3--NiO composite anodic powders for proton-conducting SOFCs prepared by a combustion method

BaZr0.8Y0.2O3- (BZY)-NiO composite powders with different BZY-NiO weight ratios were prepared by a combustion method as anodes for proton-conducting solid oxide fuel cells (SOFCs). After heating to 1100C for 6 h, the composite powders were made of a well-dispersed mixture of two phases, BZY and NiO. Chemical stability tests showed that the BZY-NiO anodic powders had good stability against CO2, whereas comparative tests under the same conditions showed degradation for BaCe0.7Zr 0.1Y0.2O3--NiO, which is at present the most used anode material for proton-conducting SOFCs. Area specific resistance (ASR) measurements for BZY-NiO anodes showed that their electrochemical performance depended on the BZY-NiO weight ratio. The best performance was obtained for the anode containing 50 wt BZY and 50 wt NiO, which showed the smallest ASR values in the whole testing temperature range (0.37 cm2 at 600C). The 50 wt BZY and 50 wt NiO anode prepared by combustion also showed superior performance than that of the BZY-NiO anode conventionally made by a mechanical mixing route, as well as that of Pt.