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Department of Health and Environmental Sciences
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1.The effects of the bioanode on the microbial community and element profile in paddy soil

Author:Williamson, G;Chen, Z


Abstract:In paddy soil the reductive dissolution of iron oxide and the availability of organic matter plays an important role in arsenic release under anaerobic conditions. Microbial fuel cells have been shown to reduce organic matter (OM) content and the rate in which this occurs strongly relate to the external resistance applied. In this study we investigated the effects of bioanode operating at different external resistance on the paddy soil microbial community and iron and arsenic concentration. The results show that MFC can be used to reduce soil pore water iron and arsenic concentration and the extent in which this occurs depend on the external resistance applied. The MFC is able to mitigate arsenic release by decreasing organic matter availability. Furthermore, our finding shows that external resistance had a significant influence on the bacterial community composition that develop on the bioanode however only had minimal effect on the community of the bulk soil. These findings suggest that the sMFC can influence the iron and arsenic concentration by reducing OM content and the microbial community that develop in the bioanode vicinity.

2.Demo Abstract: Smart City: a real-time environmental monitoring system on green roof

Author:Zhao, ZH;Wang, JH;Fu, CX;Liu, DW;Li, BL


Abstract:The research on the green roof is of great importance in the field of urban beautification and improving ecological effect. According to the previous research, plants have shown a significant impact on the absorption of PM2.5. Therefore, it is justified that the appropriate planting design or some particular combinations of plants can be considered as a solution, dealing with the urban fine particulate matter (PM2.5). This paper presented a work in progress on developing wireless sensor networks (WSN) system based on a prototype wind tunnel, which is used for the simulation of the green roof. Several data collection processes are handled by this system, where the concentration of PM2.5, wind speed, temperature & relative humidity are obtained and stored in the database simultaneously. Additionally, users are able to real-timely define their commands in details, controlling the sensor's height through a GUI on the website. Experimental and simulation results and measurements have verified the validity of the wind tunnel module as well as the reliability of the sensor network. The system can be operated on thousands of devices when the packet delay maintained in a low level.

3.Mutual relationships of suspended sediment, turbidity and visual clarity in New Zealand rivers

Author:Ballantine, DJ;Hughes, AO;Davies-Colley, RJ


Abstract:Many river water quality monitoring programmes do not measure suspended particulate matter (SPM) mass concentrations despite significant interest in its multiple effects on aquatic ecosystems. Regular monthly sampling usually intercepts rivers in baseflow when suspended sediment mass concentrations and fluxes are relatively low and not of particular interest. New Zealand's National Rivers Water Quality Network (NRWQN) is probably typical in not measuring SPM mass, although visual clarity and nephelometric turbidity are routinely measured. In order to better characterize SPM in NZ rivers, total suspended sediment (TSS) was temporarily added to the NRWQN. Turbidity, visual clarity and TSS are mutually inter-related over all 77 sites, although with considerable data scatter. However, within individual rivers turbidity and visual clarity are typically fairly closely related to TSS and provide fair to excellent surrogates. Therefore, TSS need not be measured routinely because it can be estimated with sufficient precision for many purposes from visibility or turbidity.

4.Estimating the impact threshold for wind-blown sand

Author:Li, BL;Ellis, JT;Sherman, DJ


Abstract:In many aeolian studies, it is commonplace to use Bagnold's (1936) equation to calculate threshold shear velocity (u*(t),), which includes an empirical constant, A, typically set at about 0.082 for maintaining saltation (the dynamic, or impact, threshold). Here, we present data from a pilot study to assess the variability of A to improve estimations of u*(t), which in turn, should improve transport rate predictions. Using field data from three coastal environments, we measured or calculated all parameters within the Lettau and Lettau (1978) model and u*(t) equation. In Jericoacoara, Brazil (BRA), Inch, Ireland (IRE), and Esposende, Portugal (POR) wind velocities were measured with cup anemometer towers and transport rates were measured using traps for 31 data runs lasting 120 to 1020 seconds each. Mean grain sizes were 0.17 mm (IRE), 0.31 mm (POR), and 0.30 mm (BRA), and mean shear velocities were 0.38 m s(-1) (IRE), 0.40 m s(-1) (POR), and 0.49 in 54 (BRA). Empirically determined, adjusted A values ranged from 0.02 to 0.21 with a mean and standard deviation of 0.11 and 0.04. No relationship exists between estimates of A and grain Reynolds number. A statistically significant (p < 0.001), negative relationship was found between A and mass transport rate, leading to substantial over-prediction of transport rates near the threshold and under-prediction during fast winds if a constant of 0.082 is used.

5.Thioarsenic compounds exist in the drinking groundwater

Author:Liang, JH;Chen, Z


Abstract:Arsenic (As) polluted groundwater in Northern China was used as drinking water source and caused severe health problems. Characterization of As speciation is crucial to understand the health risk of As and its biogeochemical behaviors in groundwater. In this study, groundwater samples were collected from 26 wells in Northern China. Arsenic species in the groundwater were measured by high-performance liquid chromatography (HPLC) and inductively coupled plasma mass spectrometry (ICP-MS). Thioarsenate, one of the As species that is seldom reported in drinking groundwater, was detected in two-third of the sampling wells, even in the samples with total As concentration lower than 10 mu g.L-1. Furthermore, the occurrence of thioarsenate in groundwater samples was dependent on the pH of groundwater, and thioarsenate was transformed to arsenite below a pH value of 8.2. The study demonstrated thioarsenate was prevalent in the alkaline drinking groundwater and would be a new As exposure pathway for the people and livestock living in the As-rich area.

6.Novel numerical and computational techniques for remote sensor based monitoring of freshwater quality

Author:Zhu, XH;Yue, Y;Wong, P;Zhang, YX;Meng, J


Abstract:Freshwater protection is one of the key issues for environment protection. In this paper we propose novel techniques to remotely monitor freshwater quality in river system using wireless sensor networks (WSNs). In order to maximize the performance in water quality monitoring with minimum amount of sensor nodes, we have studied optimal sensor deployment algorithm based on graph theory, genetic algorithm (GA) and storm water management model (SWIVINI). We have also proposed algorithms to automatically detect and locate the pollution and predict the subsequent reaches which will he polluted. For overcoming the power supply limitation of WSNs, both wind and solar power devices are used as a longterm energy source for sensor nodes.

7.Simultaneous electricity production and arsenic mitigation in paddy soils by using microbial fuel cells

Author:Chen, Z;Gustave, W;Yuan, ZF;Sekar, R;Chang, HC;Salaun, P;Zhang, JY


Abstract:Arsenic behavior in paddy soils is known to couple with the redox process of iron (Fe) minerals. When soil is flooded, Fe oxides are transformed to soluble ferrous ions by accepting the electrons from Fe reducers. In this study, we tried to manipulate the Fe redox processes in paddy soils by deploying sediment microbial full cells (sMFC). The results showed that the sMFC bioanode can modulate soil porewater Fe and arsenic (As) concentrations. At the end of the experiment, Fe and As contents around sMFC anode were 65.0%% and 47.0%% of the control respectively. A similar trend was observed in the sMFC bulk soil, where the Fe and As contents were 67.0%% and 89.0%% of the control respectively. This decrease in Fe and As concentrations could be attributed to the enhanced organic matter (OM) removal by sMFC. In the vicinity of bioanode, OM removal efficiencies were 10.3%% and 14.0%% higher than the control for lost on ignition carbon and organic carbon respectively. Furthermore, sequencing of the 16S rRNA genes suggested that the change in microbial community structure was minimal Moreover, during the experiment a maximum current and power density of 0.31 mA and 12.0 mWm(-2) were obtained, respectively. This study shows a novel way to make good use of As contaminated paddy soils, which is to simultaneously generate electricity and reduce the As mobility.

8.HBV and HCV test uptake and correlates among men who have sex with men in China: a nationwide cross-sectional online survey

Author:Fitzpatrick, T;Pan, SW;Tang, W;Guo, W;Tucker, JD


Total 8 results found
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