Nutrient release and sediment oxygen demand in a eutrophic land-locked embayment in Hong Kong

Tolo Harbour is a large eutrophic land-locked estuarine embayment in Hong Kong. The rapid urbanization, commercio-industrial activities and lack of legislative control around the Tolo catchment produced large quantities of untreated or partially treated municipal sewage, agricultural wastes and cottage industrial effluents which were discharged into Tolo Harbour via rivers and watercourses. Control measures were implemented to reduce the external nutrient loading into the harbour since the early 1980s. Nutrient data for the period 1982 to 1997 were analyzed for temporal trends. Over the period of observation, the total inorganic nitrogen and total phosphorus both show an increasing trend, despite a decade of efforts in reducing nutrient loading. The release rates of potentially mobile nitrogen (N) and phosphorus (P) from the sediments collected from Tolo Harbour were determined by N and P release experiments under oxic conditions. The experimental results showed that the sediment released significant amount of nutrients, especially orthophosphates and ammonia nitrogen. The maximum release rates were 15.0 and 206.0 mg/m2/day, respectively. Although the external nutrient loading has been reduced, nutrients could gradually be released back into the water column from the contaminated sediments and delay improvement of the water quality.     

Antecedents of early career stage mentoring among Chinese employees

This study examined the mediating influence of protege‐initiated mentoring relationships on the relationship between personality and situational characteristics and mentoring received. Data were obtained from Hong Kong Chinese graduate employees (N=184) in their early career stage. Results of the regression analysis showed that protege‐initiated mentoring relationships mediated the relationship between the personality (extraversion) but not the situational (individual development culture and opportunities for interactions on the job) characteristics and mentoring received. In other words, extraversion was indirectly related to mentoring received through protege‐initiated mentoring relationships but individual development culture and opportunities for interactions on the job were directly related to mentoring received. Additionally, opportunities for interactions on the job indirectly influenced mentoring received through protege‐initiated mentoring relationships. Limitations of the study, implications of the findings and directions for future research are discussed. Copyright © 1999 John Wiley & Sons, Ltd.     

Statistical method for the determination of the ignition energy of dust cloud-experimental validation

Powdery materials such as metallic or polymer powders play a considerable role in many industrial processes. Their use requires the introduction of preventive safeguard to control the plants safety. The mitigation of an explosion hazard, according to the ATEX 137 Directive (1999/92/EU), requires, among other things, the assessment of the dust ignition sensitivity. PRISME laboratory (University of Orléans) has developed an experimental set-up and methodology, using the Langlie test, for the quick determination of the explosion sensitivity of dusts. This method requires only 20 shots and ignition sensitivity is evaluated through the E₅₀ (energy with an ignition probability of 0.5). A Hartmann tube, with a volume of 1.3 l, was designed and built. Many results on the energy ignition thresholds of partially oxidised aluminium were obtained using this experimental device (Baudry, 2007) and compared to literature. E₅₀ evolution is the same as MIE but their respective values are different and MIE is lower than E₅₀ however the link between E₅₀ and MIE has not been elucidated.In this paper, the Langlie method is explained in detail for the determination of the parameters (mean value E₅₀ and standard deviation σ) of the associated statistic law. The ignition probability versus applied energy is firstly measured for Lycopodium in order to validate the method. A comparison between the normal and the lognormal law was achieved and the best fit was obtained with the lognormal law.In a second part, the Langlie test was performed on different dusts such as aluminium, cornstarch, lycopodium, coal, and PA12 in order to determine E₅₀ and σ for each dust. The energies E₀₅ and E₁₀ corresponding respectively to an ignition probability of 0.05 and 0.1 are determined with the lognormal law and compared to MIE find in literature. E₀₅ and E₁₀ values of ignition energy were found to be very close and were in good agreement with MIE in the literature.     

Exploring the interaction relationship between Beautiful China-SciTech innovation using coupling coordination and predictive analysis: a case study of Zhejiang

Environment, Development and Sustainability - Exploring interaction of Beautiful China and SciTech Innovation is an important way to realize economic transformation and sustainable development in...     

Satellite imagery: a way to monitor water quality for the future?

Environmental Science and Pollution Research - Monitoring water at high spatial and temporal resolutions is important for maintaining water quality because the cost of pollution remediation is...