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The many advantages of slug flow pneumatic conveying are outweighed by the lack of understanding of the flow mechanisms. For horizontal slug flow, the unique feature is the stationary layer of material found between the travelling slugs, which was recently shown to be characterised by two constants. This paper looks to utilise the vast data available in the literature, which is representative of the entire mode of flow, and relates the stationary layer and slug velocity to predict the two constants from only these inputs. It was found that, even for the vast range of materials and systems considered, slug flow encompasses a narrow bound of the two constants. Furthermore, an empirical approach that was developed to relate the layer fraction and particle velocity was found to provide good agreement to measurements and may be of use in other investigations that require an additional equation for modelling.

Abstract With recent developments in the design and manufacturing process of water-based fire suppression systems , more advanced technologies such as water mist systems have expanded in their building application. In this article, the critical fire suppression mechanisms of water mist systems and conventional fire sprinklers are investigated and compared, with emphasis on the influence of water droplet sizes on the fire suppression mechanisms. Applying computational fluid dynamics (CFD), a fully ventilated fire compartment room has been considered where a methane pool fire was placed at the centre. The considered fire suppression systems were placed directly upon the fire. Thermocouple and gas probes were applied in the computational domain to identify different stages of the fire suppression process, as well as to evaluate the suppression performance. The velocity field was analyzed to examine the penetration effect of suppression systems. Relative humidity and oxygen concentration data obtained by gas analyzers were also studied to further understand the droplet/fire interaction behavior. It was found that latent cooling, volumetric displacement, and dilution of oxygen and fuel were the main suppression mechanisms for water mist systems, as smaller droplets evaporate more efficiently compared to larger ones. On the other hand, for sprinklers, heat extraction by water droplets from the fire was found to be the main suppression mechanism, and the evaporation effect is not as significant as in water mist systems. According to in-depth parametric studies of water droplet sizes, recommendations for the optimal running conditions have been provided for both systems.

Abstract This study aims to gain insight into the mechanism and kinetics during the gasification of biochar in steam, which was formed in situ in a fluidised-bed reactor using mallee wood in two particle size ranges of 0.80–1.0 mm and 2.0–3.3 mm. The overall biochar gasification rate and the formation rates of key product components were calculated by continuously monitoring the product gas stream with a quadrupole mass spectrometer. The kinetic compensation effects reveal that CO and CO2 are both formed from the heterogeneous reactions between the biochar surface and H2O. CO2 is formed either by the surface (biochar)-catalysed water-gas-shift reaction or directly from the carbon active sites involving the same intermediate for the formation of CO, as revealed by the apparent activation energies and apparent pre-exponential factors for CO and CO2 formation. The changes in the particle size of biomass substrate do not affect the extent of the kinetic compensation effects of biochar consumption and formation of CO, CO2 and H2 in the kinetics-controlled and mixed regimes. The similar extent of the kinetic compensation effects of H2 formation and biochar consumption for both particle sizes indicates that the formation of H2 also mainly involve the carbon active sites on the biochar surface instead of the gas-phase water-gas-shift reaction.

A promising technology for renewable energy is energy piles used to heat and cool buildings. In this research, the effects of bio-cementation via microbially induced calcite precipitation (MICP) using mixed calcium and magnesium sources and the addition of fibres on the thermal conductivity of soil were investigated. Firstly, silica sand specimens were treated with cementation solutions containing different ratios of calcium chloride and magnesium chloride to achieve maximum thermal conductivity improvement. Three treatment cycles were provided, and the corresponding thermal conductivity was measured after each cycle. It was found that using 100% calcium chloride resulted in the highest thermal conductivity. This cementation solution was then used to treat bio-cemented soil samples containing fibres, including polyethylene, steel and glass fibres. The fibre contents used included 0.5%, 1.0% and 1.5% of the dry sand mass. The results show that the glass fibre samples yielded the highest thermal conductivity after three treatment cycles, and SEM imaging was used to support the findings. This research suggests that using MICP as a soil improvement technique can also improve the thermal conductivity of soil surrounding energy piles, which has high potential to effectively improve the efficiency of energy piles.

Abstract Non-Newtonian fluid flows through packed beds are common in many industries. Our understanding of this flow system is very limited, and the correlations for describing the fluid-particle interaction are not fully established. To overcome these problems, this paper presents a comprehensive study of this system on a sub-particle scale, with a special reference to the interaction between fluid rheology and bed properties. This is done by conducting about five hundred Lattice Boltzmann simulations under different conditions. The fluid rheology is represented by the power-law model to consider the shear-thinning, shear thickening and Newtonian behaviors of fluids. The simulation condition covers a wide range of bed porosity, particle size distribution and Reynolds number (Re). The results show that the effect of fluid rheology on the fluid behavior is strong. This effect varies significantly with bed porosity which is a function of particle size distribution. The interplay between fluid rheology and bed properties is however not strong in determining the distributions of particle-fluid interaction force. Based on the simulation data, a new drag correlation is established and validated against the experimental data in the literature. This correlation is more accurate and consistent than those reported in the past. It can estimate the mean drag forces on individual particles of different sizes, and is recommended to be used generally in the modeling of particle-fluid flows either for Newtonian fluids or for non-Newtonian fluids obeying the power-law model.

Compiling, deploying and utilising large-scale databases that integrate environmental and economic data have traditionally been labour- and cost-intensive processes, hindered by the large amount of disparate and misaligned data that must be collected and harmonised. The Australian Industrial Ecology Virtual Laboratory (IELab) is a novel, collaborative approach to compiling large-scale environmentally extended multi-region input-output (MRIO) models. The utility of the IELab product is greatly enhanced by avoiding the need to lock in an MRIO structure at the time the MRIO system is developed. The IELab advances the idea of the "mother-daughter" construction principle, whereby a regionally and sectorally very detailed "mother" table is set up, from which "daughter" tables are derived to suit specific research questions. By introducing a third tier - the "root classification" - IELab users are able to define their own mother-MRIO configuration, at no additional cost in terms of data handling. Customised mother-MRIOs can then be built, which maximise disaggregation in aspects that are useful to a family of research questions. The second innovation in the IELab system is to provide a highly automated collaborative research platform in a cloud-computing environment, greatly expediting workflows and making these computational benefits accessible to all users. Combining these two aspects realises many benefits. The collaborative nature of the IELab development project allows significant savings in resources. Timely deployment is possible by coupling automation procedures with the comprehensive input from multiple teams. User-defined MRIO tables, coupled with high performance computing, mean that MRIO analysis will be useful and accessible for a great many more research applications than would otherwise be possible. By ensuring that a common set of analytical tools such as for hybrid life-cycle assessment is adopted, the IELab will facilitate the harmonisation of fragmented, dispersed and misaligned raw data for the benefit of all interested parties.