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Chapters

Gardner, A.P. 2017, 'Flipping on a shoestring: A Case Study of Engineering Mechanics at the University of Technology Sydney' in Reidsema, C., Kavanagh, L., Hadgraft, R. & Smith, N. (eds), The Flipped Classroom: Practice and Practices in Higher Education, Springer, Singapore, pp. 163-176.

Journal articles

Abdolali, A., Ngo, H.H., Guo, W., Zhou, J.L., Zhang, J., Liang, S., Chang, S.W., Nguyen, D.D. & Liu, Y. 2017, 'Application of a breakthrough biosorbent for removing heavy metals from synthetic and real wastewaters in a lab-scale continuous fixed-bed column.', Bioresour Technol, vol. 229, pp. 78-87.
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A continuous fixed-bed study was carried out utilising a breakthrough biosorbent, specifically multi-metal binding biosorbent (MMBB) for removing cadmium, copper, lead and zinc. The effect of operating conditions, i.e. influent flow rate, metal concentration and bed depth was investigated at pH 5.5±0.1 for a synthetic wastewater sample. Results confirmed that the total amount of metal adsorption declined with increasing influent flow rate and also rose when each metal concentration also increased. The maximum biosorption capacities of 38.25, 63.37, 108.12 and 35.23mg/g for Cd, Cu, Pb and Zn, respectively, were achieved at 31cm bed height, 10mL/min flow rate and 20mg/L initial concentration. The Thomas model better described the whole dynamic behaviour of the column rather than the Dose Response and Yoon-Nelson models. Finally, desorption studies indicated that metal-loaded biosorbent could be used after three consecutive sorption, desorption and regeneration cycles by applying a semi-simulated real wastewater.

Ahmed, M.B., Zhou, J.L., Ngo, H.H., Guo, W., Johir, M.A.H. & Sornalingam, K. 2017, 'Single and competitive sorption properties and mechanism of functionalized biochar for removing sulfonamide antibiotics from water', Chemical Engineering Journal, vol. 311, pp. 348-358.
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© 2016 Elsevier B.V.Single and competitive sorption of ionisable sulphonamides sulfamethazine, sulfamethoxazole and sulfathiazole on functionalized biochar was highly pH dependent. The equilibrium data were well represented by both Langmuir and Freundlich models for single solutes, and by the Langmuir model for competitive solutes. Sorption capacity and distribution coefficient values decreased as sulfathiazole > sulfamethoxazole > sulfamethazine. The sorption capacity of each antibiotic in competitive mode is about three times lower than in single solute sorption. The kinetics data were best described by the pseudo second-order (PSO) model for single solutes, and by PSO and intra-particle diffusion models for competitive solutes. Adsorption mechanism was governed by pore filling through diffusion process. The findings from pH shift, FTIR spectra and Raman band shift showed that sorption of neutral sulfonamide species occurred mainly due to strong H-bonds followed by π+-π electron-donor-acceptor (EDA), and by Lewis acid-base interaction. Moreover, EDA was the main mechanism for the sorption of positive sulfonamides species. The sorption of negative species was mainly regulated by proton exchange with water forming negative charge assisted H-bond (CAHB), followed by the neutralization of –OH groups by H+ released from functionalized biochar surface; in addition π-π electron-acceptor-acceptor (EAA) interaction played an important role.

Ahmed, M.B., Zhou, J.L., Ngo, H.H., Guo, W., Thomaidis, N.S. & Xu, J. 2017, 'Progress in the biological and chemical treatment technologies for emerging contaminant removal from wastewater: A critical review.', Journal of hazardous materials, vol. 323, pp. 274-298.
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This review focuses on the removal of emerging contaminants (ECs) by biological, chemical and hybrid technologies in effluents from wastewater treatment plants (WWTPs). Results showed that endocrine disruption chemicals (EDCs) were better removed by membrane bioreactor (MBR), activated sludge and aeration processes among different biological processes. Surfactants, EDCs and personal care products (PCPs) can be well removed by activated sludge process. Pesticides and pharmaceuticals showed good removal efficiencies by biological activated carbon. Microalgae treatment processes can remove almost all types of ECs to some extent. Other biological processes were found less effective in ECs removal from wastewater. Chemical oxidation processes such as ozonation/H2O2, UV photolysis/H2O2 and photo-Fenton processes can successfully remove up to 100% of pesticides, beta blockers and pharmaceuticals, while EDCs can be better removed by ozonation and UV photocatalysis. Fenton process was found less effective in the removal of any types of ECs. A hybrid system based on ozonation followed by biological activated carbon was found highly efficient in the removal of pesticides, beta blockers and pharmaceuticals. A hybrid ozonation-ultrasound system can remove up to 100% of many pharmaceuticals. Future research directions to enhance the removal of ECs have been elaborated.

Aryal, R., Beecham, S., Sarkar, B., Chong, M.N., Kinsela, A., Kandasamy, J. & Vigneswaran, S. 2017, 'Readily Wash-Off Road Dust and Associated Heavy Metals on Motorways', Water, Air, and Soil Pollution, vol. 228, no. 1.
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© 2016, Springer International Publishing Switzerland.Road dust contains a wide range of potentially health-hazardous pollutant sources. In this study, road dust samples were collected from nine locations along the Sydney orbital motorway during wet weather events and analysed for their mineralogy and heavy metal contents. The aim of this study was to examine for the specific particle size fractions in road dust samples that can be associated with anthropogenic pollutant sources, mainly on the prevalence of heavy metals. Surface morphological and elemental composition of the road dust particles was analysed using scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX). The heavy metal contents and degree of contamination were also investigated including in the two specific particle size fractions of <75 and 75–150 μm. It was found that the particle size fraction of <75 μm made up between 6 and 16% of the entire particle size distributions and contributed to more than 90% of the heavy metal contents. In addition, a moderate to high degree of heavy metal contamination was measured in the collected road dust samples, and this was correlated well with the local traffic volumes. The good correlation between heavy metals and traffic volumes in the finer road dust particle size fraction of <75 μm indicated that the finer road dust particles were not only important in terms of heavy metal attachment, accumulation and mobilisation during wet weather events but they could also provide evidence of potential anthropogenic pollution sources. These findings will facilitate our scientific understanding on the specific role and importance of particle size fractions on the mobilisation of pollutant sources, particularly heavy metals during wet weather events. It is anticipated that this study will assist in the development of best management practices for pollution prevention and control strategies on the frequency of road sweeping and retention p...

Chekli, L., Eripret, C., Park, S.H., Tabatabai, S.A.A., Vronska, O., Tamburic, B., Kim, J.H. & Shon, H.K. 2017, 'Coagulation performance and floc characteristics of polytitanium tetrachloride (PTC) compared with titanium tetrachloride (TiCl4) and ferric chloride (FeCl3) in algal turbid water', Separation and Purification Technology, vol. 175, pp. 99-106.
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© 2016 Elsevier B.V.Seasonal green algae blooms in freshwaters have raised attention on the need to develop novel effective treatment processes for the removal of algae in water. In the present study, the performance of newly developed polytitanium tetrachloride (PTC) coagulant for the removal of freshwater microalga Chlorella vulgaris has been investigated and compared with titanium tetrachloride (TiCl4) coagulant and the conventional ferric chloride (FeCl3) coagulant. The main benefit of using titanium-based coagulants is that the sludge produced after flocculation may be recycled into a valuable product: titanium dioxide photocatalyst. Both titanium-based coagulants achieved good flocculation over a broader pH range and coagulant dose compared to conventional FeCl3 coagulant. All three coagulants achieved comparable performance in terms of turbidity removal (i.e. turbidity removal efficiency >97%); although TiCl4 performed slightly better at the lower tested dose (i.e. <9 mg/L). Zeta potential measurements indicated that charge neutralisation may not be the sole mechanism involved in the coagulation of algae for all three coagulants. Analysis of the dynamic floc size variation during floc breakage showed no regrowth after floc breakage for the three coagulants. The flocs formed by both Ti-based coagulants were larger than those formed by FeCl3 and also grew at a faster rate. This study indicates that Ti-based coagulants are effective and promising coagulants for algae removal in water.

Chekli, L., Kim, Y., Phuntsho, S., Li, S., Ghaffour, N., Leiknes, T. & Shon, H.K. 2017, 'Evaluation of fertilizer-drawn forward osmosis for sustainable agriculture and water reuse in arid regions.', J Environ Manage, vol. 187, pp. 137-145.
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The present study focused on the performance of the FDFO process to achieve simultaneous water reuse from wastewater and production of nutrient solution for hydroponic application. Bio-methane potential (BMP) measurements were firstly carried out to determine the effect of osmotic concentration of wastewater achieved in the FDFO process on the anaerobic activity. Results showed that 95% water recovery from the FDFO process is the optimum value for further AnMBR treatment. Nine different fertilizers were then tested based on their FO performance (i.e. water flux, water recovery and reverse salt flux) and final nutrient concentration. From this initial screening, ammonium phosphate monobasic (MAP), ammonium sulfate (SOA) and mono-potassium phosphate were selected for long term experiments to investigate the maximum water recovery achievable. After the experiments, hydraulic membrane cleaning was performed to assess the water flux recovery. SOA showed the highest water recovery rate, up to 76% while KH2PO4 showed the highest water flux recovery, up to 75% and finally MAP showed the lowest final nutrient concentration. However, substantial dilution was still necessary to comply with the standards for fertigation even if the recovery rate was increased.

Chen, G., Liu, R., Shon, H.K., Wang, Y., Song, J., Li, X.M. & He, T. 2017, 'Open porous hydrophilic supported thin-film composite forward osmosis membrane via co-casting for treatment of high-salinity wastewater', Desalination, vol. 405, pp. 76-84.
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© 2016High-performance thin film composite (TFC) forward osmosis (FO) membranes with a low degree of internal concentration polarization (ICP) are critical for concentrating high-salinity wastewaters. This report focuses on the preparation of TFC FO membranes via a sacrificial approach. In order to improve the FO flux, hydrophilicity and morphology of the support membrane were mainly investigated. The hydrophilicity of the polysulfone (PSF) substrate was tuned by blending with sulfonated poly (ether ether ketone) (SPEEK), and the resulting SPEEK blended PSF membrane was denoted as SPSF substrate. The pore structure of the SPSF membrane was tailored by the application of a co-casting technique, which yielded a TFC membrane with a structure parameter (S) of 191 μm. In contrast, the TFC membranes based on the PSF and SPSF substrates through single layer casting showed S values of 527 μm and 361 μm, respectively. These results indicate that the combined hydrophilicity and open pore structure are responsible for the lowered S value. Further application of the hydrophilic substrate based TFC membranes in the treatment of high salinity wastewaters (10 wt%) demonstrated the higher initial water flux (28.3 L/m2·h) with a water recovery rate of 53.2% in comparison to the TFC membrane based on the pristine PSF through the single layer casting. This new method paves a way to generate high-performing FO membranes.

Chen, X., Liu, Y., Peng, L. & Ni, B.J. 2017, 'Perchlorate, nitrate, and sulfate reduction in hydrogen-based membrane biofilm reactor: Model-based evaluation', Chemical Engineering Journal, vol. 316, pp. 82-90.
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© 2017 Elsevier B.V.A biofilm model was developed to evaluate the key mechanisms including microbially-mediated ClO4−, NO3−, and SO42− reduction in the H2-based membrane biofilm reactor (MBfR). Sensitivity analysis indicated that the maximum growth rate of H2-based denitrification (μ1) and maximum growth rate of H2-based SO42− reduction (μ3) could be reliably estimated by fitting the model predictions to the experimental measurements. The model was first calibrated using the experimental data of a single-stage H2-based MBfR fed with different combinations of ClO4−, NO3−, and/or SO42− together with a constant dissolved oxygen (DO) concentration at three operating stages. μ1 and μ3 were determined at 0.133 h−1 and 0.0062 h−1, respectively, with a good level of identifiability. The model and the parameter values were further validated based on the experimental data of a two-stage H2-based MBfR system fed with ClO4−, NO3−, SO42−, and DO simultaneously but at different feeding rates during two running phases. The validated model was then applied to evaluate the quantitative and systematic effects of key operating conditions on the reduction of ClO4−, NO3−, and SO42− as well as the steady-state microbial structure in the biofilm of a single-stage H2-based MBfR. The results showed that i) a higher influent ClO4− concentration led to a higher ClO4− removal efficiency, compensated by a slightly decreasing SO42− removal; ii) the H2 loading should be properly managed at certain critical level to maximize the ClO4− and NO3− removal while limiting the growth of sulfate reducing bacteria which would occur in the case of excessive H2 supply; and iii) a moderate hydraulic retention time and a relatively thin biofilm were required to maintain high-level removal of ClO4− and NO3− but restrict the SO42− reduction.

Chung, W.J., Torrejos, R.E.C., Park, M.J., Vivas, E.L., Limjuco, L.A., Lawagon, C.P., Parohinog, K.J., Lee, S.P., Shon, H.K., Kim, H. & Nisola, G.M. 2017, 'Continuous lithium mining from aqueous resources by an adsorbent filter with a 3D polymeric nanofiber network infused with ion sieves', Chemical Engineering Journal, vol. 309, pp. 49-62.
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© 2016 Elsevier B.V. All rights reserved.Electrospun composite nanofiber (NF) was fabricated and employed as an adsorbent membrane filter in a continuous Li+ mining process from seawater. The filter was composed of a hydrophilic polyacrylonitrile (PAN) matrix infused with lithium ion sieves (LIS) H1.6Mn1.6O4. Characterization of the LIS/PAN NF confirmed its favorable structural and surface properties for effective Li+ adsorption. The LIS/PAN NF was mechanically suitable as a microfiltration membrane with high water flux and low pressure requirement. Breakthrough experiments at varied feed concentrations (Cf), seawater flowrates (F), and NF thicknesses (Z) revealed the dynamic adsorption behavior of the filter. The seawater residence time was most critical and must be kept ≥0.12 min at any given Cf and Z to maximize the Li+ capacity of the filter. This can be conveniently achieved by adjusting the F of the process. Analogous to a packed bed system, the predictive power of nine breakthrough models were determined through non-linear regression analyses. Results reveal that bed-depth-space-time, Bohart-Adams (BA) and Thomas models adequately predicted the performance of the filter albeit BA exhibited the best agreement. Meanwhile, Wolborska failed to converge with any of the experimental results while Yoon-Nelson, Wang, Clark, dose-response, and modified dose-response were too simple to provide any meaningful information. Cycled Li+ adsorption-desorption runs successfully collected and concentrated Li+ in a mild acid stripping solution. After ten cycles, Li+ was separated 155-1552 times more efficiently than Na+, K+, Mg2+ and Ca2+. Overall results demonstrate the potential of LIS/PAN NF as an adsorbent membrane filter for continuous Li+ mining from aqueous resources.

Erkmen, R.E., Mohareb, M. & Afnani, A. 2017, 'Multi-Scale Overlapping Domain Decomposition to Consider Elasto-Plastic Local Buckling Effects in the Analysis of Pipes', International Journal of Structural Stability and Dynamics, vol. 17, no. 1, pp. 1-28.
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© 2016 World Scientific Publishing Company Elevated pipelines are commonly encountered in petro-chemical and industrial applications. Within these applications, pipelines normally span hundreds of meters and are thus analyzed using one-dimensional (1D) beam-type finite elements when the global behavior of the pipeline is sought at a reasonably low computational cost. Standard beam-type elements, while computationaly economic, are based on the assumption of rigid cross-section. Thus, they are unable to capture the effects of cross-sectional localized deformations. Such effects can be captured through shell-type finite element models. For long pipelines, shell models become prohibitively expensive. Within this context, the present study formulates an efficient numerical modeling which effectively combines the efficiency of beam-type solutions while retaining the accuracy of shell-type solutions. An appealing feature of the model is that it is able to split the global analysis based on simple beam-type elements from the local analysis based on shell-type elements. This is achieved through domain-decomposition procedure within the framework of the Bridging multi-scale method of analysis. Solutions based on the present model are compared to those based on full shell-type analysis. The comparison demonstrates the accuracy and efficiency of the proposed method.

Far, H. 2017, 'Development of Synthetic Soil Mixture for Experimental Shaking Table Tests on Building Frames Resting on Soft Soils', Geomechanics and Geoengineering : An International Journal, vol. 12, no. 1, pp. 28-35.
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In this study, a synthetic soil mixture has been developed and proposed for experimental soil-structure interaction shaking table tests on building frames with shallow foundations resting on soft soil deposits. To find the most appropriate mixture, different mixes with different proportion of mix components were examined in soils laboratory. Performing bender element tests, shear wave velocity of the soil specimens were acquired at different cure ages and the results were examined and compared. Based on the test results, a synthetic clay mixture consisting of kaolinite clay, bentonite, fly ash, lime and water has been proposed for experimental shaking table tests. The proposed mix provides adequate undrained shear strength to mobilise the required shallow foundation bearing capacity underneath the structural model while meeting both criteria of dynamic similarity between the model and the prototype to model soft soils in shaking table tests.

Far, H. & Flint, D. 2017, 'Significance of Using Isolated Footing Technique for Residential Construction on Expansive Soils', Frontiers of Structural and Civil Engineering.
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Expansive soils cause problems with the founding of lightly loaded structures in many parts of the world. Foundation design for expansive soils is one of the most discussed and problematic issues in Australia as expansive soils were responsible for billions of dollars’ worth of damage to man-made structures such as buildings and roads. Several studies and reports indicate that one of the most common and least recognized problems causing severe structural damage to houses lies in expansive soils. In this study, a critical review has been carried out on the current Australian standards for building on expansive soils and they are compared with some techniques that are not included in the current Australian standards for residential slabs and footings. Based on the results of this review, the most effective and economical method has been proposed for construction of footings on all site classifications without restriction to 75mm of characteristic movement. In addition, it has become apparent that as design procedures for footings resting on sites with extreme characteristic movements are not included in the current Australian standards, there is a strong need for well-developed and simplified standard design procedures for characteristic soil movement of greater than 75mm to be included into the Australian Standards.

Ho, L. & Fatahi, B. 2017, 'Axisymmetric consolidation in unsaturated soil deposit subjected to time-dependent loadings', International Journal of Geomechanics, vol. 17, no. 2.
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© 2016 American Society of Civil Engineers.This paper presents an analytical solution to predict the axisymmetric consolidation in unsaturated soil deposits subjected to different time-dependent loadings. The mathematical procedure uses the separation of variables and Laplace transformation methods to obtain the final solution. A set of polar governing equations of flow are obtained and presented under the partial differential equations (PDEs), and then the variable separation technique is used to alter the PDEs to ordinary differential equations (ODEs) consisting of distinctive variables. Fourier Bessel and sine series are used to present functions of radial and vertical flows, respectively, and the Laplace transformation is used to obtain a function of time. Four primary time-dependent loading functions, including ramping, asymptotic, sinusoid, and damped sine wave, are mathematically simulated and incorporated into the proposed solutions. This study investigates changes in excess pore-air and pore-water pressures as well as consolidation settlement against the air-to-water permeability ratio and various loading parameters. Moreover, changes in suction and net stress induced by ramped and asymptotic loadings are also presented in the worked examples.

Hu, Y., Wang, X.C., Sun, Q., Ngo, H.H., Yu, Z., Tang, J. & Zhang, Q. 2017, 'Characterization of a hybrid powdered activated carbon-dynamic membrane bioreactor (PAC-DMBR) process with high flux by gravity flow: Operational performance and sludge properties.', Bioresour Technol, vol. 223, pp. 65-73.
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Three PAC-DMBRs were developed for wastewater treatment under different PAC dosages with biomass concentrations averaged at 2.5, 3.5 and 5.0g/L. The DMBRs could be continuously operated at 40-100L/m(2)h, while higher fluxes were obtained within the PAC-DMBRs with hydraulic retention times varying in 4-10h. A dose of 1g/L PAC brought about obvious improvement in the sludge particle size distribution, settling, flocculating and dewatering properties due to the formation of biological PAC, and the sludge properties were further improved at a higher PAC dose (3g/L). The addition of PAC notably shortened the DM formation time after air backwashing and enhanced pollutant removal. Moreover, under a long solid retention time (approximately 150d), the concentrations of both soluble and bound extracellular polymeric substances (EPS) decreased substantially because of the adsorption and biodegradation effects of the biological PAC. No obvious impact on biomass activity was observed with PAC addition.

Kang, Y., Zhang, J., Xie, H., Guo, Z., Ngo, H.H., Guo, W. & Liang, S. 2017, 'Enhanced nutrient removal and mechanisms study in benthic fauna added surface-flow constructed wetlands: The role of Tubifex tubifex.', Bioresour Technol, vol. 224, pp. 157-165.
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This study designed a combined benthic fauna-T. orientalis-substrate-microbes surface-flow constructed wetlands (SFCWs) through the addition of T. tubifex. Results showed that, the removal efficiencies of nitrogen and phosphorus in the tested SFCWs achieved 81.14±4.16% and 70.49±7.60%, which were 22.27% and 27.35% higher than that without T. tubifex. Lower nitrate (2.11±0.79mg/L) and ammonium (0.75±0.64mg/L) were also observed in the tested SFCWs, which were 3.46mg/L and 0.52mg/L lower than that without T. tubifex. Microbial study confirmed the increased denitrifiers with T. tubifex. The lower nitrogen in effluent was also attributed to higher contents of nitrogen storage in sediment and T. orientalis due to the bioturbation of T. tubifex. Furthermore, with T. tubifex, higher proportions of particulate (22.66±3.96%) and colloidal phosphorus (20.57±3.39%) observed promoted phosphorus settlement and further absorption by T. orientalis. The outcomes of this study provides an ecological and economical strategy for improving the performance of SFCWs.

Kim, J., Blandin, G., Phuntsho, S., Verliefde, A., Le-Clech, P. & Shon, H. 2017, 'Practical considerations for operability of an 8″ spiral wound forward osmosis module: Hydrodynamics, fouling behaviour and cleaning strategy', Desalination, vol. 404, pp. 249-258.
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© 2016 Elsevier B.V.A better understanding of large spiral wound forward osmosis (SW FO) module operation is needed to provide practical insight for a full-scale FO practical implementation desalination plant. Therefore, this study investigated two different 8″ SW FO modules (i.e. cellulose tri acetate, CTA and thin film composite, TFC) in terms of hydrodynamics, operating pressure, water and solute fluxes, fouling behaviour and cleaning strategy. For both modules, a significantly lower flow rate was required in the draw channel than in the feed channel due to important pressure-drop in the draw channel and was a particularly critical operating challenge in the CTA module when permeate spacers are used. Under FO and pressure assisted osmosis (PAO, up to 2.5 bar) operations, the TFC module featured higher water flux and lower reverse salt flux than the CTA module. For both modules, fouling tests demonstrated that feed inlet pressure was more sensitive to foulant deposition than the flux, thus confirming that FO fouling deposition occurs in the feed channel rather than on the membrane surface. Osmotic backwash combined with physical cleaning used in this study confirmed to be effective and adapted to large-scale FO module operation.

Le, T.M., Fatahi, B., Khabbaz, H. & Sun, W. 2017, 'Numerical optimization applying trust-region reflective least squares algorithm with constraints to optimize the non-linear creep parameters of soft soil', Applied Mathematical Modelling, vol. 41, pp. 236-256.
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Determination of the creep model parameters is a challenging task particularly when a non-linear elastic visco-plastic (EVP) model is adopted, mainly due to the limited test duration as well as the assumption of the reference time. Therefore, this paper presents an innovative numerical solution to find the EVP model parameters applying the trust-region reflective least square optimization algorithm. The developed approach involves several available laboratory consolidation test results in the optimization procedure with the adopted commencing time to creep as a unit of time. In this paper, the laboratory results of Ottawa clay were employed to demonstrate the limitation of the recent method to obtain model parameters. Furthermore, the developed method is verified against Skå-Edeby clay in the laboratory conditions. The EVP model parameters are obtained by applying the developed method to the available laboratory consolidation results of clay samples. The analysis results of vertical strains and excess pore water pressures demonstrate that the developed method can be a feasible tool to estimate the settlement properties of clays.

Lee, E.J., An, A.K., Hadi, P., Lee, S., Woo, Y.C. & Shon, H.K. 2017, 'Advanced multi-nozzle electrospun functionalized titanium dioxide/polyvinylidene fluoride-co-hexafluoropropylene (TiO2/PVDF-HFP) composite membranes for direct contact membrane distillation', Journal of Membrane Science, vol. 524, pp. 712-720.
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© 2016 Elsevier B.V.The unique capabilities of electrospinning technology are being increasingly utilized in the fabrication of hydrophobic membranes to improve the membrane distillation (MD) process in recent years. In this study, hydrophobic titanium dioxide (TiO2) nanoparticles functionalized by fluorosilane were incorporated into electrospun membranes using single, coaxial, and dual nozzles to develop novel membrane architectures for improved physico-chemical properties for MD. By incorporating fluorosilane coated TiO2 into the PVDF-HFP solution during the membrane synthesis and using an advanced multi-nozzle to form various hierarchical membrane structures tuned the size and structure of the nanofibers and made them vastly superior for the application in MD. The single and coaxial nozzle membranes showed contact angles close to 150° and the dual-nozzle membrane assembled bead-on-string fibers achieved superhydrophobicity (i.e., contact angle of 153.4°). To test the functionalized titanium dioxide/polyvinylidene fluoride-co-hexafluoropropylene (TiO2/PVDF-HFP) composite membranes for MD performance, the membranes were subjected to long-term direct contact MD for about two days to monitor their water vapor flux and selectivity. Compared to commercial PVDF membranes, all electrospun F-TiO2/ PVDF-HFP membrane achieved higher water vapor flux of 40 L m−2 h−1 (60 °C feed and 20 °C permeate) with a brine (7.0 wt% NaCl) as the feed solution and also exhibited anti-wetting property while maintaining high water flux compared to the membrane without TiO2 incorporation.

Lee, J., Jeong, S., Ye, Y., Chen, V., Vigneswaran, S., Leiknes, T.O. & Liu, Z. 2017, 'Protein fouling in carbon nanotubes enhanced ultrafiltration membrane: Fouling mechanism as a function of pH and ionic strength', Separation and Purification Technology, vol. 176, pp. 323-334.
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© 2016 Elsevier B.V.The protein fouling behavior was investigated in the filtration of the multiwall carbon nanotube (MWCNT) composite membrane and commercial polyethersulfone ultrafiltration (PES-UF) membrane. The effect of solution chemistry such as pH and ionic strength on the protein fouling mechanism was systematically examined using filtration model such as complete pore blocking, intermediate pore blocking and cake layer formation. The results showed that the initial permeate flux pattern and fouling behavior of the MWCNT composite membrane were significantly influenced by pH and ionic strength while the effect of PES-UF membrane on flux was minimal. In a lysozyme (Lys) filtration, the severe pore blocking in the MWCNT membrane was made by the combined effect of intra-foulant interaction (Lys-Lys) and electrostatic repulsion between the membrane surface and the foulant at pH 7, and increasing ionic strength where the foulant-foulant interaction and membrane-fouling interaction were weak. In a bovine serum albumin (BSA) filtration, severe pore blocking was reduced by less deposition via the electrostatic interaction between the membrane and foulant at pH 4.7 and 10.4 and increasing ionic strength, at which the interaction between the membrane and BSA became weak. For binary mixture filtration, the protein fouling mechanism was more dominantly affected by foulant-foulant interaction (Lys-BSA, Lys-Lys, and BSA-BSA) at pH 7.0 and increase in ionic strength. This research demonstrates that MWCNT membrane fouling can be alleviated by changing pH condition and ionic strength based on the foulant-foulant interaction and the electrostatic interaction between the membrane and foulant.

Li, J., Hao, H. & Wu, C. 2017, 'Numerical study of precast segmental column under blast loads', Engineering Structures, vol. 134, pp. 125-137.
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© 2016 Elsevier LtdConstructions with precast technology have seen a fast development over the past several decades. Despite advantages including short construction period, better quality control, less environmental and traffic impact, a lack of study on their behaviour under dynamic loads have prevented the widespread use of precast constructions in high seismic zones and where terrorist attack could be a concern. Among all precast structural components, precast segmental columns have been found one of the construction techniques with great potentials. Intensive research efforts have been spent on investigating the segmental columns under seismic loadings in recent years. During its service life, besides seismic action, structure may subject to other dynamic loads like impact and blast. It is therefore important to perform multi-hazard analyse to better understand structural performance. This study investigates the blast loading resistance capacities of segmental reinforced concrete (RC) columns. RC segmental columns with or without shear keys and energy dissipation bars are considered. Influence of the number of segments and different levels of post tensioning forces on column dynamic performance is also investigated. Commercial code LS-DYNA is used to perform numerical simulations of the segmental columns under different blast loadings. Accuracy of the numerical model is verified against available testing data on RC columns. Numerical results of the segmental columns under different blast loadings are calculated and compared with those of the monolithic RC columns. Discussions on the capabilities of segmental RC columns in resisting blasting loads are made with respect to those of the monolithic RC columns.

Li, J., Wu, C., Hao, H. & Liu, Z. 2017, 'Post-blast capacity of ultra-high performance concrete columns', Engineering Structures, vol. 134, pp. 289-302.
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Li, J., Wu, C., Hao, H. & Su, Y. 2017, 'Experimental and numerical study on steel wire mesh reinforced concrete slab under contact explosion', Materials and Design, vol. 116, pp. 77-91.
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© 2016 Elsevier LtdWith the rising of terrorism and rapid urbanization around the world, increasingly more structures are exposed to the threats from accidental and hostile explosion loads. To provide adequate structural protection against blast load, novel materials and strengthening techniques are under fast development. In the present study, a composite slab design aiming at high level blast resistance is studied. In the matrix of high strength self-compacting concrete, besides conventional rebars serving as primary reinforcement, steel wire meshes are embedded and served as secondary reinforcements. Moreover, on the concrete cover layer where the tensile cracks locate, steel fibres are added to provide micro crack-bridging effect. Preliminary numerical simulations adopting coupled Finite Element (FE) and Smoothed Particle Hydrodynamics (SPH) are carried out in hydro-code and the results are used as guide for field blast test. Composite slab with optimal design is field tested under 1 kg TNT contact detonation, and the results are compared with slabs made of conventional and ultra-high performance concrete without steel wire meshes. The results demonstrate that slab with steel wire mesh reinforcement develops localized membrane effect when subjected to blast loads and shows better blast resistant capability as compared to the slabs without steel wire meshes.

Li, W., Huang, Z., Hu, G., Hui Duan, W. & Shah, S.P. 2017, 'Early-age shrinkage development of ultra-high-performance concrete under heat curing treatment', Construction and Building Materials, vol. 131, pp. 767-774.
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© 2016 Elsevier LtdThe effects of a novel heat curing regime and longitudinal reinforcement ratio on early-age shrinkage of ultra-high performance concrete (UHPC) were experimentally investigated in this study. The microstructure, porosity and calcium hydroxide (CH) content of UHPC after different heat curing durations were characterized with scanning electron microscopy, mercury intrusion porosimetry and thermal analysis. The results indicate that slight shrinkage was observed when the heat curing duration was less than 60 min and curing temperature reached 48 °C. However, when the heat curing duration approached 70 min and curing temperature was around 55 °C, the early-age shrinkage increased dramatically. It was found that the early-age shrinkage is approximately 450 με after 48 h of heat curing. The results also show that the early-age shrinkage of UHPC significantly decreased by percentage of 33–60% with the increase of longitudinal steel reinforcement ratio from 2.0 to 4.52%. Meantime, after 10 h of heat curing, the cement hydration and secondary hydration in UHPC tend to finish, which consequently leads to dense microstructure and low CH content in UHPC.

Li, X., Mo, Y., Li, J., Guo, W. & Ngo, H.H. 2017, 'In-situ monitoring techniques for membrane fouling and local filtration characteristics in hollow fiber membrane processes: A critical review', Journal of Membrane Science, vol. 528, pp. 187-200.
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© 2017 Elsevier B.V.Membrane fouling is the most serious challenge in the hollow fiber microfiltration (MF) and ultrafiltration (UF) processes. A number of in-situ monitoring techniques including optical and non-optical probes have been developed so that membrane fouling is better understood and controlled. This will help advance the membrane technology. In addition, the local filtration hydrodynamics wield a great influence on the membrane fouling formation and system operation stability. State-of-the-art in-situ monitoring techniques for membrane fouling and local filtration characteristics in hollow fiber MF/UF processes are critically reviewed. The principles and applications of these techniques are addressed in order to assess their strengths. This study demonstrated that the real-time observation techniques mainly focus on idealized laboratory apparatus and little on commercial membrane modules. Consequently, more attention should be paid to the development of simple and effective methods or integrated detecting technology so as to satisfy the real status of hollow fiber filtration processes and the optimization of membrane module. On the basis of this review, future analyses considering practical requirements are suggested as R&D priorities.

Li, X., Tao, M., Wu, C., Du, K. & Wu, Q. 2017, 'Spalling strength of rock under different static pre-confining pressures', International Journal of Impact Engineering, vol. 99, pp. 69-74.
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© 2016 Elsevier LtdA testing method of spalling strength at different static pre-confining pressure is proposed in this paper. Using a modified split Hopkinson bar facility, a static pre-confining pressure was loaded before dynamic loading. The pull-back method is used to calculate the spalling strength and the free surface velocities of the specimen were measured by a laser detector system. The experimental results indicate that the spalling strength is related to the static pre-confining pressures. When the impact loading and rate effect are almost the same, the results demonstrated that the spalling strength decreases with an increase in the confining pressure.

Li, Y. & Li, J. 2017, 'On rate-dependent mechanical model for adaptive magnetorheological elastomer base isolator', Smart Materials and Structures, vol. 26, no. 4.
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Lim, S., Park, M.J., Phuntsho, S., Tijing, L.D., Nisola, G.M., Shim, W.G., Chung, W.J. & Shon, H.K. 2017, 'Dual-layered nanocomposite substrate membrane based on polysulfone/graphene oxide for mitigating internal concentration polarization in forward osmosis', Polymer (United Kingdom), vol. 110, pp. 36-48.
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© 2016 Elsevier LtdA novel thin-film composite (TFC) forward osmosis (FO) membrane with dual-layered substrate membrane was fabricated by a double-blade casting technique using different polysulfone (PSf) concentrations for top (15 wt%) and bottom (7 wt%) substrate layers. Graphene oxide (GO) was incorporated in the substrate layer, and the dual casting approach resulted in a membrane support with a highly porous bottom structure and a dense top skin layer on which the polyamide active layer was effectively formed. The dual-layered TFC PSf/GO membrane (TFC-PSfdGO) exhibited high water permeability, and ion selectivity was enhanced by the presence of well dispersed hydrophilic GO in the PSf substrate. The TFC-PSfdGO also exhibited the lowest specific reverse salt flux (Js/Jv = 0.19 g L-1) and a more favorable structural parameter (S = 130 μm) compared to GO-free membranes. Using deionized water as feed solution and 1 M NaCl as draw solution (DS), TFC-PSfdGO had Jv = 33.8 L m−2 h−1 and Js = 6.9 g−2 h−1 under AL-FS mode, and Jv = 61.5 L m−2h−1 and Js = 14.0 g−2 h−1 under AL-DS mode. The potential of TFC-PSfdGO for commercial application was further evaluated by fabricating it with a fabric backing support (denoted as TFC-PSfdGOf). Compared to TFC-PSfdGO, TFC-PSfdGOf exhibited only 14% decline in its water flux. The overall results reveal that, fabrication of TFC substrate membrane via dual-blade casting approach along with GO incorporation produced high-performance TFC FO membranes which likely reduced the internal concentration polarization effects.

Liu, J., Wu, C. & Chen, X. 2017, 'Numerical study of ultra-high performance concrete under non-deformable projectile penetration', Construction and Building Materials, vol. 135, pp. 447-458.
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Liu, Y., Zhang, Y., Zhao, Z., Ngo, H.H., Guo, W., Zhou, J., Peng, L. & Ni, B.-.J. 2017, 'A modeling approach to direct interspecies electron transfer process in anaerobic transformation of ethanol to methane.', Environ Sci Pollut Res Int, vol. 24, no. 1, pp. 855-863.
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Recent studies have shown that direct interspecies electron transfer (DIET) plays an important part in contributing to methane production from anaerobic digestion. However, so far anaerobic digestion models that have been proposed only consider two pathways for methane production, namely, acetoclastic methanogenesis and hydrogenotrophic methanogenesis, via indirect interspecies hydrogen transfer, which lacks an effective way for incorporating DIET into this paradigm. In this work, a new mathematical model is specifically developed to describe DIET process in anaerobic digestion through introducing extracellular electron transfer as a new pathway for methane production, taking anaerobic transformation of ethanol to methane as an example. The developed model was able to successfully predict experimental data on methane dynamics under different experimental conditions, supporting the validity of the developed model. Modeling predictions clearly demonstrated that DIET plays an important role in contributing to overall methane production (up to 33 %) and conductive material (i.e., carbon cloth) addition would significantly promote DIET through increasing ethanol conversion rate and methane production rate. The model developed in this work will potentially enhance our current understanding on syntrophic metabolism via DIET.

Loganathan, P., Naidu, G. & Vigneswaran, S. 2017, 'Mining valuable minerals from seawater: A critical review', Environmental Science: Water Research and Technology, vol. 3, no. 1, pp. 37-53.
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©2017 The Royal Society of Chemistry.Seawater contains large quantities of valuable minerals, some of which are very scarce and expensive in their land-based form. However, only a few minerals, the ones in high concentrations, are currently mined from the sea. Due to recent problems associated with land-based mining industries as a result of depletion of high-grade ores, sustainable water and energy demand and environmental issues, seawater mining is becoming an attractive option. This paper presents a comprehensive and critical review of the current methods of extracting valuable minerals from seawater and seawater brines generated in desalination plants, and suggests ways to overcome some of the limitations and challenges associated with the extraction process. The extraction methods discussed are solar evaporation, electrodialysis (ED), membrane distillation crystallisation (MDC), and adsorption/desorption.

Naidu, G., Jeong, S., Choi, Y. & Vigneswaran, S. 2017, 'Membrane distillation for wastewater reverse osmosis concentrate treatment with water reuse potential', Journal of Membrane Science, vol. 524, pp. 565-575.
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© 2016 Elsevier B.V.Membrane distillation (MD) was evaluated as a treatment option of wastewater reverse osmosis concentrate (WWROC) discharged from wastewater reclamation plants (WRPs). A direct contact MD (DCMD), at obtaining 85% water recovery of WWROC showed only 13–15% flux decline and produced good quality permeate (10–15 µS/cm, 99% ion rejection) at moderate feed temperature of 55 °C. Prevalent calcium carbonate (CaCO3) deposition on the MD membrane occurred in treating WWROC at elevated concentrations. The combination of low salinity and loose CaCO3 adhesion on the membrane did not significantly contribute to DCMD flux decline. Meanwhile, high organic content in WWROC (58–60 mg/L) resulted in a significant membrane hydrophobicity reduction (70% lower water contact angle than virgin membrane) attributed to low molecular weight organic adhesion onto the MD membrane. Granular activated carbon (GAC) pretreatment helped in reducing organic contents of WWROC by 46–50%, and adsorbed a range of hydrophobic and hydrophilic micropollutants. This ensured high quality water production by MD (micropollutants-free) and enhanced its reuse potential. The MD concentrated WWROC was suitable for selective ion precipitation, promising a near zero liquid discharge in WRPs.

Naidu, G., Shim, W.G., Jeong, S., Choi, Y.K., Ghaffour, N. & Vigneswaran, S. 2017, 'Transport phenomena and fouling in vacuum enhanced direct contact membrane distillation: Experimental and modelling', Separation and Purification Technology, vol. 172, pp. 285-295.
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© 2016 Elsevier B.V.The application of vacuum to direct contact membrane distillation (vacuum enhanced direct contact membrane distillation, V-DCMD) removed condensable gasses and reduced partial pressure in the membrane pores, achieving 37.6% higher flux than DCMD at the same feed temperature. Transfer mechanism and temperature distribution profile in V-DCMD were studied. The empirical flux decline (EFD) model represented fouling profiles of V-DCMD. In a continuous V-DCMD operation with moderate temperature (55 °C) and permeate pressure (300 mbar) for treating wastewater ROC, a flux of 16.0 ± 0.3 L/m2 h and high quality distillate were achieved with water flushing, showing the suitability of V-DCMD for ROC treatment.

Narottam Saha, M. Safiur Rahman, Ahmed, M., ZHou, Ngo & Guo 2017, 'Industrial metal pollution in water and probabilistic assessment of human health risk', Journal of Environmental Management, vol. 185, pp. 70-78.
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Concentration of eight heavy metals in surface and groundwater around Dhaka Export Processing Zone (DEPZ) industrial area were investigated, and the health risk posed to local children and adult residents via ingestion and dermal contact was evaluated using deterministic and probabilistic approaches. Metal concentrations (except Cu, Mn, Ni, and Zn) in Bangshi River water were above the drinking water quality guidelines, while in groundwater were less than the recommended limits. Concentration of metals in surface water decreased as a function of distance. Estimations of non-carcinogenic health risk for surface water revealed that mean hazard index (HI) values of As, Cr, Cu, and Pb for combined pathways (i.e., ingestion and dermal contact) were >1.0 for both age groups. The estimated risk mainly came from the ingestion pathway. However, the HI values for all the examined metals in groundwater were <1.0, indicating no possible human health hazard. Deterministically estimated total cancer risk (TCR) via Bangshi River water exceeded the acceptable limit of 1 104 for adult and children. Although, probabilistically estimated 95th percentile values of TCR exceeded the benchmark, mean TCR values were less than 1 104 . Simulated results showed that 20.13% and 5.43% values of TCR for surface water were >1 104 for adult and children, respectively. Deterministic and probabilistic estimations of cancer risk through exposure to groundwater were well below the safety limit. Overall, the population exposed to Bangshi River water remained at carcinogenic and non-carcinogenic health threat and the risk was higher for adults. Sensitivity analysis identified exposure duration (ED) and ingestion rate (IR) of water as the most relevant variables affecting the probabilistic risk estimation model outcome. ©

Nguyen, D.D., Chang, S.W., Cha, J.H., Jeong, S.Y., Yoon, Y.S., Lee, S.J., Tran, M.C. & Ngo, H.H. 2017, 'Dry semi-continuous anaerobic digestion of food waste in the mesophilic and thermophilic modes: New aspects of sustainable management and energy recovery in South Korea', Energy Conversion and Management, vol. 135, pp. 445-452.
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© 2016 Elsevier LtdIn this study, parallel, bench-scale, mesophilic and thermophilic, dry, semi-continuous anaerobic digestion (DScAD) of Korea food waste (FW, containing 22% total solids (TS) and 20% volatile solids (VS)) was investigated thoroughly under varying operational conditions, including hydraulic retention times (HRTs) and organic loading rates (OLRs). The aim was to evaluate the start-up, stability, overall removal efficiency, and inhibitory effects of toxic compounds on process performance over a long-term operation lasting 100 days. The results from both digesters indicate that the simultaneous reduction of VS and the production of gas improved as the HRT decreased or the OLR increased. The highest average rates of VS reduction (79.67%) and biogas production (162.14 m3 biogas/ton of FW, 61.89% CH4), at an OLR of 8.62 ± 0.34 kg VS/m3 day (25 days of HRT), were achieved under thermophilic DScAD. In addition, the average rates of reduction of VS and the production of biogas in thermophilic DScAD were higher by 6.88% and 16.4%, respectively, than were those in mesophilic DScAD. The inhibitory effects of ammonia, H2S, and volatile fatty acids (VFAs) on methane production was not clear from either of the digesters, although, apparently, their concentrations did fluctuate. This fluctuation could be attributed to the self-adaptation of the microbial well. However, digestion that was more stable and faster was observed under thermophilic conditions compared with that under mesophilic conditions. Based on our results, the optimum operational parameters to improve FW treatment and achieve higher energy yields could be determined, expanding the application of DScAD in treating organic wastes.

Nguyen, L., Fatahi, B. & Khabbaz, H. 2017, 'Development of a Constitutive Model to Predict the Behavior of Cement-Treated Clay during Cementation Degradation: C3 Model', International Journal of Geomechanic.
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Qu, X., Yi, W., Wang, T., Wang, S., Xiao, L. & Liu, Z. 2017, 'Mixed-Integer Linear Programming Models for Teaching Assistant Assignment and Extensions', Scientific Programming, vol. 2017.
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© 2017 Xiaobo Qu et al.In this paper, we develop mixed-integer linear programming models for assigning the most appropriate teaching assistants to the tutorials in a department. The objective is to maximize the number of tutorials that are taught by the most suitable teaching assistants, accounting for the fact that different teaching assistants have different capabilities and each teaching assistant's teaching load cannot exceed a maximum value. Moreover, with optimization models, the teaching load allocation, a time-consuming process, does not need to be carried out in a manual manner. We have further presented a number of extensions that capture more practical considerations. Extensive numerical experiments show that the optimization models can be solved by an off-the-shelf solver and used by departments in universities.

Roobavannan, M., Kandasamy, J., Pande, S., Vigneswaran, S. & Sivapalan, M. 2017, 'Allocating Environmental Water and Impact on Basin Unemployment: Role of A Diversified Economy', Ecological Economics, vol. 136, pp. 178-188.
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© 2017 Elsevier B.V.Water diversion for environmental purposes threatens many agricultural communities. This paper focuses on the water-agriculture-environment nexus in the Murrumbidgee River Basin, Australia, and attempts to explain how reduced water allocation to agriculture aimed at protecting the environment in turn impacted the wider economy and the community. Predictably reduced water allocation saw declines in agriculture production and employment. Despite this, paradoxically, the basin unemployment rate declined and basin median household income increased. To understand and interpret this, we first analyze available labour, economic and hydrology data, and then develop a simple dynamic model to interpret the observed pattern of basin employment and unemployment. Data analysis revealed the likely causes behind the paradox as (a) out-migration of people from the basin, and (b) absorption of the labour force in the fast growing non-agricultural sectors of the diversified basin economy. The model simulations reinforced this interpretation. Further model simulations under alternative realities of out-migration and sectoral transformation indicated that basins embedded in faster growing national economies, and are more diversified to begin with, are likely to be more conducive to agriculture sector reform (e.g., reduced water allocation) and environmental regeneration. This is a sobering message for other regions experiencing environmental degradation due to extensive agricultural development.

Shanmuganathan, S., Loganathan, P., Kazner, C., Johir, M.A.H. & Vigneswaran, S. 2017, 'Submerged membrane filtration adsorption hybrid system for the removal of organic micropollutants from a water reclamation plant reverse osmosis concentrate', DESALINATION, vol. 401, pp. 134-141.
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Sountharajah, D.P., Kus, B., Kandasamy, J. & Vigneswaran, S. 2017, 'Quantifying the reduction in water demand due to rainwater tank installations at residential properties in sydney', Journal of Sustainable Development of Energy, Water and Environment Systems, vol. 5, no. 2, pp. 202-218.
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© 2017, International Centre for Sustainable Development of Energy, Water and Environment Systems SDEWES. All rights reserved.This paper examines data on actual reductions in consumption of water supply due to the widespread installation of rainwater tanks at residential properties in the Sydney metropolitan area and surrounding areas connected to Sydney Water Corporation water supply mains. The water consumption was based on metered potable water usage between 2002 and 2009. The number of properties in the study database totalled 962,697 single residential dwellings. Of this a total of 52,576 or 5.5% of Sydney’s households had a rainwater tank registered with Sydney Water Corporation. The water usage consumption before and after the installation of the rainwater tank was analysed to quantify the extent to which rainwater tanks reduced mains water consumption. The average percentage of water savings by installing rainwater tanks across all 44 local government authorities was 9%. In some Sydney localities this reduction was up to 15%. On average, a household was able to save around 24 kilolitre of water annually by installing a rainwater tank even without considering other factors that affect water usage. The results were compared against socio-demographic factors using variables such as household size, educational qualifications, taxable income, rented properties, and non-English-speaking background, etc., to gain an appreciation of how these factors may have influenced the outcomes evident in the data. Among the co-relations found were that most properties within inner Sydney with a rainwater tank achieved at least a 9 to 11% additional reduction in water usage, with more than half of those local government authorities achieving more than 11%; properties with larger land area were more likely to have a rainwater tank installed; local government authorities with more people born in non-English speaking countries had lower reduction in water consumption reductions...

Sounthararajah, D.P., Loganathan, P., Kandasamy, J. & Vigneswaran, S. 2017, 'Removing heavy metals using permeable pavement system with a titanate nano-fibrous adsorbent column as a post treatment', Chemosphere, vol. 168, pp. 467-473.
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© 2016 Elsevier LtdPermeable pavement systems (PPS) are a widely-used treatment measure in sustainable stormwater management and groundwater recharge. However, PPS are not very efficient in removing heavy metals from stormwater. A pilot scale study using zeolite or basalt as bed material in PPS removed 41–72%, 67–74%, 38–43%, 61–72%, 63–73% of Cd, Cu, Ni, Pb, and Zn, respectively, from synthetic stormwater (pH 6.5; Cd, Cu, Ni, Pb, and Zn concentrations of 0.04, 0.6, 0.06, 1.0, and 2.0 mg L−1, respectively) over a period of 80 h. The total volume of stormwater that passed through the PPS was equivalent to runoff in 10 years of rainfall in Sydney, Australia. The concentrations of metals in the PPS effluent failed fresh and marine water quality trigger values recommended in the Australian and New Zealand guidelines. An addition of a post-treatment of a horizontal filter column containing a titanate nano-fibrous (TNF) material with a weight < 1% of zeolite weight and mixed in with granular activated carbon (GAC) at a GAC:TNF weight ratio of 25:1 removed 77% of Ni and 99–100% of all the other metals. The effluent easily met the required standards of marine waters and just met those concerning fresh waters. Batch adsorption data from solutions of metals mixtures fitted the Langmuir model with adsorption capacities in the following order, TNF ≫ zeolite > basalt; Pb > Cu > Cd, Ni, Zn.

Su, Y., Li, J., Wu, C., Wu, P., Tao, M. & Li, X. 2017, 'Mesoscale study of steel fibre-reinforced ultra-high performance concrete under static and dynamic loads', Materials and Design, vol. 116, pp. 340-351.
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© 2016 Elsevier LtdIn this paper, a three-dimensional numerical model to study the static and dynamic behaviour of ultra-high performance steel fibre reinforced concrete is developed. Ultra-high performance steel fibre reinforced concrete is assumed to be a two-phase model consisting of concrete matrix and steel fibres. The concrete matrix is modelled with homogeneous material and the straight round steel fibres are assumed to be dispersed with random locations and orientations in the matrix. The interfacial transition zone (ITZ) effect is studied based on the single fibre pull-out tests, and parameters describing the fibre-matrix one dimensional bond-slip behaviour are obtained and discussed based on both experimental and theoretical results. After the three-dimensional model is validated with static split tensile tests, split Hopkinson pressure bar (SHPB) split tensile tests are numerically modelled and the stress-time history is interpreted in the mesoscale level. The proposed model qualitatively and quantitatively predicts the material static and dynamic behaviours, and also gives insights on the fibre reinforcement effect in the concrete matrix.

Su, Y., Wu, C., Li, J., Li, Z.-.X. & Li, W. 2017, 'Development of novel ultra-high performance concrete: From material to structure', Construction and Building Materials, vol. 135, pp. 517-528.
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Sun, J., Dai, X., Liu, Y., Peng, L. & Ni, B.J. 2017, 'Sulfide removal and sulfur production in a membrane aerated biofilm reactor: Model evaluation', Chemical Engineering Journal, vol. 309, pp. 454-462.
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© 2016 Elsevier B.V.Sulfide removal from wastewater is essential, in view of the toxic, malodor and corrosive property of sulfide. The oxidation of sulfide by chemolithotrophic sulfide oxidation bacteria can produce elemental sulfur, an important chemical material. A membrane aerated biofilm reactor (MABR) has been successfully implemented and demonstrated for enhanced sulfide oxidation and sulfur production, owning to its counter-diffusion design of oxygen supply. In this work, a mathematical model was developed to evaluate the sulfide oxidation and sulfur production in the MABR in the presence of residual organics in the influent. The model was calibrated and validated using the experimental data from the long-term operation of the sulfide-oxidation MABR at different operational stages. The results suggested that the developed model could satisfactorily describe sulfide oxidation, sulfur production, sulfate accumulation and organics conversion in the MABR. The modelling results indicated that with the optimal combinations of sulfide loading and oxygen pressure, over 90% of sulfide removal and over 75% of sulfur recovery could be achieved. The sulfide oxidation and sulfur production would also be affected by the biofilm area to reactor volume (A/V) ratio in the MABR, with high A/V ratio might deteriorate the sulfur production efficiency depending on the oxygen pressure applied. Further, the increase of volatile fatty acids in the wastewater would not affect the sulfide oxidation efficiency but could enhance the sulfur production efficiency by decreasing the amount of sulfur oxidized to sulfate.

Sun, Y., Indraratna, B., Carter, J.P., Marchant, T. & Nimbalkar, S. 2017, 'Application of fractional calculus in modelling ballast deformation under cyclic loading', Computers and Geotechnics, vol. 82, pp. 16-30.
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© 2016 Elsevier LtdMost constitutive models can only simulate cumulative deformation after a limited number of cycles. However, railroad ballast usually experiences a large number of train passages that cause history-dependent long-term deformation. Fractional calculus is an efficient tool for modelling this phenomenon and therefore is incorporated into a constitutive model for predicting the cumulative deformation. The proposed model is further validated by comparing the model predictions with a series of corresponding experimental results. It is observed that the proposed model can realistically simulate the cumulative deformation of ballast from the onset of loading up to a large number of load cycles.

Vu, T.M., Trinh, V.T., Doan, D.P., Van, H.T., Nguyen, T.V., Vigneswaran, S. & Ngo, H.H. 2017, 'Removing ammonium from water using modified corncob-biochar', Science of the Total Environment, vol. 579, pp. 612-619.
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Ammonium pollution in groundwater and surface water is of major concern in many parts of the world due to the danger it poses to the environment and people's health. This study focuses on the development of a low cost adsorbent, specifically a modified biochar prepared from corncob. Evaluated here is the efficiency of this new material for removing ammonium from synthetic water (ammonium concentration from 10 to 100 mg/L). The characteristics of the modified biochar were determined by Brunauer-Emmett-Teller (BET) test, Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM). It was found that ammonium adsorption on modified biochar strongly depended on pH. Adsorption kinetics of NH4+-N using modified biochar followed the pseudo-second order kinetic model. Both Langmuir and Sips adsorption isotherm models could simulate well the adsorption behavior of ammonium on modificated biochar. The highest adsorption capacity of 22.6 mg NH4+-N/g modified biochar was obtained when the biochar was modified by soaking it in HNO3 6 M and NaOH 0.3 M for 8 h and 24 h, respectively. The high adsorption capacity of the modified biochar suggested that it is a promising adsorbent for NH4+-N remediation from water

Vu, T.M., Trinh, V.T., Doan, D.P., Van, H.T., Nguyen, T.V., Vigneswaran, S. & Ngo, H.H. 2017, 'Removing ammonium from water using modified corncob-biochar', Science of the Total Environment, vol. 579, pp. 612-619.
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Ammonium pollution in groundwater and surface water is of major concern in many parts of the world due to the danger it poses to the environment and people's health. This study focuses on the development of a low cost adsorbent, specifically a modified biochar prepared from corncob. Evaluated here is the efficiency of this new material for removing ammonium from synthetic water (ammonium concentration from 10 to 100 mg/L). The characteristics of the modified biochar were determined by Brunauer-Emmett-Teller (BET) test, Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM). It was found that ammonium adsorption on modified biochar strongly depended on pH. Adsorption kinetics of NH4+-N using modified biochar followed the pseudo-second order kinetic model. Both Langmuir and Sips adsorption isotherm models could simulate well the adsorption behavior of ammonium on modificated biochar. The highest adsorption capacity of 22.6 mg NH4+-N/g modified biochar was obtained when the biochar was modified by soaking it in HNO3 6 M and NaOH 0.3 M for 8 h and 24 h, respectively. The high adsorption capacity of the modified biochar suggested that it is a promising adsorbent for NH4+-N remediation from water

Wang, H., Wu, C., Zhang, F., Fang, Q., Xiang, H., Li, P., Li, Z., Zhou, Y., Zhang, Y. & Li, J. 2017, 'Experimental study of large-sized concrete filled steel tube columns under blast load', Construction and Building Materials, vol. 134, pp. 131-141.
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© 2016This paper investigates blast resistance and residual strength of concrete-filled steel tube (CFST) columns under close-range blast loads. A total of 8 CFST columns, including 4 with circular cross sections and 4 with square cross sections, were tested under close-range blasts. LVDTs were used to record displacement histories and pressure sensors were used to measure pressure histories. The influence of explosive charge weight, steel tube thickness and cross section geometry on dynamic response of CFST columns was analyzed and failure modes of CFST columns were also investigated. Following the blast tests, an experimental study was conducted to investigate residual strength of blast-damaged CFST columns. It was found that the CFST columns were still able to retain a large portion of their axial load capacities even after close-range blast events.

Wang, J., Pathak, N., Chekli, L., Phuntsho, S., Kim, Y., Li, D. & Shon, H.K. 2017, 'Performance of a novel fertilizer-drawn forward osmosis aerobic membrane bioreactor (FDFO-MBR): Mitigating salinity build-up by integrating microfiltration', Water (Switzerland), vol. 9, no. 1.
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© 2017 by the authors.In this paper, three different fertilizer draw solutions were tested in a novel forward osmosis-microfiltration aerobic membrane bioreactor (MF-FDFO-MBR) hybrid system and their performance were evaluated in terms of water flux and reverse salt diffusion. Results were also compared with a standard solution. Results showed that ammonium sulfate is the most suitable fertilizer for this hybrid system since it has a relatively high water flux (6.85 LMH) with a comparatively low reverse salt flux (3.02 gMH). The performance of the process was also studied by investigating different process parameters: draw solution concentration, FO draw solution flow rate and MF imposed flux. It was found that the optimal conditions for this hybrid system were: draw solution concentration of 1 M, FO draw solution flow rate of 200 mL/min and MF imposed flux of 10 LMH. The salt accumulation increased from 834 to 5400 μS/cm during the first four weeks but after integrating MF, the salinity dropped significantly from 5400 to 1100 μS/cm suggesting that MF is efficient in mitigating the salinity build up inside the reactor. This study demonstrated that the integration of the MF membrane could effectively control the salinity and enhance the stable FO flux in the OMBR.

Wang, S., Qu, X., Wang, T. & Yi, W. 2017, 'Optimal Container Routing in Liner Shipping Networks Considering Repacking 20 ft Containers into 40 ft Containers', Journal of Advanced Transportation, vol. 2017, pp. 1-9.
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Wang, X. & Wang, J.G. 2017, 'Detecting glass in Simultaneous Localisation and Mapping', Robotics and Autonomous Systems, vol. 88, pp. 97-103.
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© 2016Simultaneous Localisation and Mapping (SLAM) has become one of key technologies used in advanced robot platform. The current state-of-art indoor SLAM with laser scanning rangefinders can provide accurate realtime localisation and mapping service to mobile robotic platforms such as PR2 robot. In recent years, many modern building designs feature large glass panels as one of the key interior fitting elements, e.g. large glass walls. Due to the transparent nature of glass panels, laser rangefinders are unable to produce accurate readings which causes SLAM functioning incorrectly in these environments. In this paper, we propose a simple and effective solution to identify glass panels based on the specular reflection of laser beams from the glass. Specifically, we use a simple technique to detect the reflected light intensity profile around the normal incident angle to the glass panel. Integrating this glass detection method with an existing SLAM algorithm, our SLAM system is able to detect and localise glass obstacles in realtime. Furthermore, the tests we conducted in two office buildings with a PR2 robot show the proposed method can detect ∼95% of all glass panels with no false positive detection. The source code of the modified SLAM with glass detection is released as a open source ROS package along with this paper.

Wei, D., Zhang, K., Ngo, H.H., Guo, W., Wang, S., Li, J., Han, F., Du, B. & Wei, Q. 2017, 'Nitrogen removal via nitrite in a partial nitrification sequencing batch biofilm reactor treating high strength ammonia wastewater and its greenhouse gas emission.', Bioresour Technol, vol. 230, pp. 49-55.
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In present study, the feasibility of partial nitrification (PN) process achievement and its greenhouse gas emission were evaluated in a sequencing batch biofilm reactor (SBBR). After 90days' operation, the average effluent NH4(+)-N removal efficiency and nitrite accumulation rate of PN-SBBR were high of 98.2% and 87.6%, respectively. Both polysaccharide and protein contents were reduced in loosely bound extracellular polymeric substances (LB-EPS) and tightly bound EPS (TB-EPS) during the achievement of PN-biofilm. Excitation-emission matrix spectra implied that aromatic protein-like, tryptophan protein-like and humic acid-like substances were the main compositions of both kinds of EPS in seed sludge and PN-biofilm. According to typical cycle, the emission rate of CO2 had a much higher value than that of N2O, and their total amounts per cycle were 67.7 and 16.5mg, respectively. Free ammonia (FA) played a significant role on the inhibition activity of nitrite-oxidizing bacteria and the occurrence of nitrite accumulation.

Woo, Y.C., Chen, Y., Tijing, L.D., Phuntsho, S., He, T., Choi, J.S., Kim, S.H. & Shon, H.K. 2017, 'CF4 plasma-modified omniphobic electrospun nanofiber membrane for produced water brine treatment by membrane distillation', Journal of Membrane Science, vol. 529, pp. 234-242.
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© 2017 Elsevier B.V.This study describes the development and performance of an omniphobic poly(vinylidene fluoride) (PVDF) membrane by electrospinning and CF4 plasma surface modification for air gap membrane distillation (AGMD). The effect of different duration of plasma treatment on the nanofiber membrane characteristics was investigated. The AGMD performance of the membranes was evaluated using real reverse osmosis (RO) brine produced from coal seam gas (CSG) water that was added with low surface tension liquid (surfactant) as feed solution. Results indicated the formation of new CF2-CF2 and CF3 bonds after plasma treatment, which lowered the surface energy of the membrane, providing omniphobic property, as indicated by its wetting resistance to different low surface tension liquids such as methanol, mineral oil and ethylene glycol. Though no appreciative changes in morphology of the membrane were observed after plasma treatment, optimal treatment condition of 15 min (i.e., P/CF-15 membrane) exhibited lotus effect membrane surface with increased liquid entry pressure of 187 kPa compared to 142 kPa for neat membrane. AGMD performance showed stable normalized flux (initial flux of 15.3 L/m2h) and rejection ratio (100%) for P/CF-15 even with the addition of up to 0.7 mM sodium dodecyl sulfate surfactant to the RO brine from CSG produced water feed, while commercial PVDF membrane suffered membrane wetting after 0.3 mM of surfactant addition. Based on the results, the present omniphobic membrane has good potential for producing clean water from challenging waters containing high salinity and organic contaminants.

Woo, Y.C., Tijing, L.D., Park, M.J., Yao, M., Choi, J.S., Lee, S., Kim, S.H., An, K.J. & Shon, H.K. 2017, 'Electrospun dual-layer nonwoven membrane for desalination by air gap membrane distillation', Desalination, vol. 403, pp. 187-198.
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© 2015 Elsevier B.V. In the present study, dual-layer nanofiber nonwoven membranes were prepared by a facile electrospinning technique and applied for desalination by air gap membrane distillation (AGMD). Neat single and dual-layer nanofiber membranes composed of a hydrophobic polyvinylidene fluoride-co-hexafluoropropylene (PH) top layer with different supporting hydrophilic layer made of either polyvinyl alcohol (PVA), nylon-6 (N6), or polyacrylonitrile (PAN) nanofibers were fabricated with and without heat-press post-treatment. Surface characterization showed that the active layer (i.e., PH) of all electrospun nanofiber membranes (ENMs) exhibited a rough, highly porous (>80% porosity), and hydrophobic surface (CA>140°), while the other side was hydrophilic (CA<90°) with varying porosity. Heat-pressing the membrane resulted to thinner thickness (from >129μm to <100μm) and smaller pore sizes (<0.27μm). The AGMD experiments in a co-current flow set-up were carried out with constant inlet temperatures at the feed and permeate streams of 60±1.5 and 20±1.5°C, respectively. The AGMD module had a membrane area of 21cm<sup>2</sup> and the thickness of the air gap was 3mm. The neat single and dual-layer ENMs showed a water permeate flux of about 10.9-15.5L/m<sup>2</sup> h (LMH) using 3.5wt.% NaCl solution as feed, which was much higher than that of a commercial PVDF membrane (~5LMH). The provision of a hydrophilic layer at the bottom layer enhanced the AGMD performance depending on the wettability and characteristics of the support layer. The PH/N6 dual-layer nanofiber membrane prepared under the optimum condition showed flux and salt rejection of 15.5LMH and 99.2%, respectively, which has good potential for AGMD application.

Wu, H., Zhang, J., Ngo, H.H., Guo, W. & Liang, S. 2017, 'Evaluating the sustainability of free water surface flow constructed wetlands: Methane and nitrous oxide emissions', Journal of Cleaner Production, vol. 147, pp. 152-156.
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© 2017 Elsevier LtdConstructed wetlands (CWs) have been used as a green technology to treat various wastewaters for several decades, and greenhouse gases production in these systems attracted increasing attention considering the contributions of methane and nitrous oxide emissions to global warming. However, the detailed knowledge about the contribution of CWs to methane and nitrous oxide emissions in treating sewage treatment plant effluent are still limited in particular for a better understanding of the sustainability of CWs. The fluxes of methane (CH4) and nitrous oxide (N2O) from free water surface (FWS) CWs in northern China were measured continuously using the static-stationary chamber technique from 2012 to 2013. The results showed that CWs were the significant source of CH4 and N2O emissions. Average emission rates of CH4 and N2O ranged from −30.2 μg m−2 h−1 to 450.9 μg m−2 h−1, and -58.8 μg m−2 h−1 to 1251.8 μg m−2 h−1, respectively. Obvious annual and seasonal variations of CH4 and N2O emissions were observed over the 2-year period. In addition, temperatures and plant species had an impact on CH4 and N2O emissions. The obtained results showed that FWS CWs, improving water quality but emitting lower CH4 and N2O, could be the alternative method for sewage treatment plant effluent.

Wu, Y., Yang, Q., Zeng, Q., Ngo, H.H., Guo, W. & Zhang, H. 2017, 'Enhanced low C/N nitrogen removal in an innovative microbial fuel cell (MFC) with electroconductivity aerated membrane (EAM) as biocathode', Chemical Engineering Journal, vol. 316, pp. 315-322.
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© 2016 Elsevier B.V.A novel microbial fuel cell (MFC) was developed to enhance simultaneous nitrification and denitrification (SND) by employing electrons from the anode. The cathode chamber of the reactor consisted of a membrane aerated biofilm reactor (MABR) which was made of an electroconductivity aerated membrane. The maximum power density of 4.20 ± 0.12 W m−3 was obtained at a current density of 4.10 ± 0.11 A m−2 (external resistance = 10 Ω). Compared with an open-circuit system, the removal rates of NH4+-N and TN were improved by 9.48 ± 0.33% and 19.80 ± 0.84%, respectively, which could be ascribed to the electrochemical denitrification. The anode (chemical oxygen demand, COD) and cathode (NO3−) chambers reached the maximum coulombic efficiencies (CEs) of 40.67 ± 1.05% and 42.84 ± 1.14%, respectively. It suggested that the electroconductivity MABR has some advantages in controlling aeration intensity, thus improving SND and CEs. Overall, EAM-MFC could successfully generate electricity from wastewater whilst showing high capacity for removing nitrogen at a low COD/N ratio of 2.8 ± 0.07 g COD g−1 N.

Yao, M., Woo, Y.C., Tijing, L.D., Cesarini, C. & Shon, H.K. 2017, 'Improving nanofiber membrane characteristics and membrane distillation performance of heat-pressed membranes via annealing post-treatment', Applied Sciences (Switzerland), vol. 7, no. 1.
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© 2017 by the authors.Electrospun membranes are gaining interest for use in membrane distillation (MD) dueto their high porosity and interconnected pore structure however, they are still susceptible towetting during MD operation because of their relatively low liquid entry pressure (LEP). In thisstudy, post-treatment had been applied to improve the LEP, as well as its permeation and saltrejection efficiency. The post-treatment included two continuous procedures: heat-pressing andannealing. In this study, annealing was applied on the membranes that had been heat-pressed.It was found that annealing improved the MD performance as the average flux reached 35 L/m2hor LMH (>10% improvement of the ones without annealing) while still maintaining 99.99% saltrejection. Further tests on LEP, contact angle, and pore size distribution explain the improvementdue to annealing well. Fourier transform infrared spectroscopy and X-ray diffraction analysesof the membranes showed that there was an increase in the crystallinity of the polyvinylidenefluoride-co-hexafluoropropylene (PVDF-HFP) membrane also, peaks indicating the α phase ofpolyvinylidene fluoride (PVDF) became noticeable after annealing, indicating some βand amorphousstates of polymer were converted into the α phase. The changes were favorable for membranedistillation as the non-polar α phase of PVDF reduces the dipolar attraction force between themembrane and water molecules, and the increase in crystallinity would result in higher thermalstability. The present results indicate the positive effect of the heat-press followed by an annealingpost-treatment on the membrane characteristics and MD performance.

Ye, Y., Ngo, H.H., Guo, W., Liu, Y., Li, J., Liu, Y., Zhang, X. & Jia, H. 2017, 'Insight into chemical phosphate recovery from municipal wastewater.', Sci Total Environ, vol. 576, pp. 159-171.
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Phosphate plays an irreplaceable role in the production of fertilizers. However, its finite availability may not be enough to satisfy increasing demands for the fertilizer production worldwide. In this scenario, phosphate recovery can effectively alleviate this problem. Municipal wastewater has received high priority to recover phosphate because its quantity is considerable. Therefore, phosphate recovery from municipal wastewater can bring many benefits such as relieving the burden of increasing production of fertilizers and reduction in occurrence of eutrophication caused by the excessive concentration of phosphate in the released effluent. The chemical processes are the most widely applied in phosphate recovery in municipal wastewater treatment because they are highly stable and efficient, and simple to operate. This paper compares chemical technologies for phosphate recovery from municipal wastewater. As phosphate in the influent is transferred to the liquid and sludge phases, a technical overview of chemical phosphate recovery in both phases is presented with reference to mechanism, efficiency and the main governing parameters. Moreover, an analysis on their applications at plant-scale is also presented. The properties of recovered phosphate and its impact on crops and plants are also assessed with a discussion on the economic feasibility of the technologies.

Zhang, F., Wu, C., Zhao, X.L. & Li, Z.X. 2017, 'Numerical derivation of pressure-impulse diagrams for square UHPCFDST columns', Thin-Walled Structures, vol. 115, pp. 188-195.
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© 2017Terrorist activities, especially bomb attacks, have become more and more frequent in the past decades which put thousands of innocent lives in danger. The most common failure mode of structures subjected to blast loading is progressive collapse which is mainly resulted from the failure of load bearing columns. In this paper, finite element analysis tool, LS-DYNA is utilized to study the behaviours of ultra-high performance concrete filled double- skin steel tube (UHPCFDST) columns under blast loading. The numerical model is firstly validated against a series of laboratory and field tests and then used to derive pressure-impulse diagrams for UHPCFDST columns in terms of their residual axial load-carrying capacity after being subjected to blast loading. Different parameters are studied to investigate the effects of axial load ratio, steel tube thickness, column dimension and concrete strength on the pressure-impulse diagrams.

Zhang, J., Sun, H., Wang, W., Hu, Z., Yin, X., Ngo, H.H., Guo, W. & Fan, J. 2017, 'Enhancement of surface flow constructed wetlands performance at low temperature through seasonal plant collocation.', Bioresour Technol, vol. 224, pp. 222-228.
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In the present study, a novel seasonal plant collocation system (SPCS), specifically the Potamogeton crispus and Phragmites australis series system, was investigated to enhance the performance of surface flow constructed wetlands (SFCWs) at low temperature. Results of a year-round experiment showed that SPCS conquered the adverse effect of low temperature and achieved sustainable nutrients removal. In addition, during winter, removal efficiencies of NH4-N, TP, COD, and TN in SPCS were 18.1%, 17.6%, 10.1% and 5.2% higher than that in the control, respectively. P. crispus and P. australis complemented each other in terms of plant growth and plant uptake during the experiment period. Furthermore, it emerged that P. crispus could increase the quantity of ammonia oxidizing bacteria by 10.2%, due to its high oxygen enrichment ability. It is suggested that seasonal plant collocation has a promising future in SFCWs of areas being affected by climate change, e.g. northern China.

Zhao, Y., Sun, Y., Tian, C., Gao, B., Wang, Y., Shon, H. & Yang, Y. 2017, 'Titanium tetrachloride for silver nanoparticle-humic acid composite contaminant removal in coagulation-ultrafiltration hybrid process: floc property and membrane fouling.', Environ Sci Pollut Res Int, vol. 24, no. 2, pp. 1757-1768.
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Titanium-based coagulation is expected to achieve both efficient water purification and sludge recycling. This study is the first attempt to use titanium tetrachloride (TiCl4) for silver nanoparticle (AgNP)-humic acid composite contaminant removal in a coagulation-ultrafiltration (C-UF) process, where characterization of flocs and membrane fouling under varied coagulant dose, initial solution pH, and AgNP concentration conditions are the main contents. Results suggested that the TiCl4 achieved high AgNP removal in the form of silver nanoparticle through adsorption and sweep flocculation and simultaneously exerted additional 68.2 % higher dissolved organic carbon removal than Al2(SO4)3. The TiCl4 produced larger and stronger flocs but with weaker recoverability and less compact degree than did Al2(SO4)3. Floc properties were independent of AgNP concentration except floc fractal dimension, which was negatively correlated with AgNP concentration. The TiCl4 precoagulation caused less membrane fouling within wider pH range than Al2(SO4)3 did in the C-UF process. Incorporation of AgNPs during the TiCl4 pretreatment process facilitated the mitigation of membrane fouling, which was, however, negligibly influenced by AgNP concentration in the case of Al2(SO4)3.