HKU's double professional civil engineering and law programme

The scale and complexity of civil engineering projects are increasing exponentially. Coupled with the growing trend of globalisation, the demand for high-calibre civil engineers who are also knowledgeable in legal matters is increasing. Driven by an aspiration to prepare civil engineering graduates with a solid foundation in both civil engineering and law, The University of Hong Kong has developed the first 5-year credit-based double professional degree programme in Hong Kong, which leads to the award of the degrees of Bachelor of Engineering in Civil Engineering (Law) and Bachelor of Laws. The considerations, development process and launching details of the programme are presented in this paper. The students admitted to date perform better academically than other civil engineering students on civil engineering courses. However, they do not perform as well as law students and other law-related double-degree students.published_or_final_versio

Assessing photochemical ozone formation in the Pearl River Delta with a photochemical trajectory model

A photochemical trajectory model (PTM), coupled with the Master Chemical Mechanism (MCM) describing the degradation of 139 volatile organic compounds (VOCs) in the troposphere, was developed and used for the first time to simulate the formation of photochemical pollutants at Wangqingsha (WQS), Guangzhou during photochemical pollution episodes between 12 and 17 November, 2007. The simulated diurnal variations and mixing ratios of ozone were in good agreement with observed data (R2=0.80, P<0.05), indicating that the photochemical trajectory model - an integration of boundary layer trajectories, precursor emissions and chemical processing - provides a reasonable description of ozone formation in the Pearl River Delta (PRD) region. Calculated photochemical ozone creation potential (POCP) indices for the region indicated that alkanes and oxygenated organic compounds had relatively low reactivity, while alkenes and aromatics presented high reactivity, as seen in other airsheds in Europe. Analysis of the emission inventory found that the sum of 60 of the 139 VOC species accounted for 92% of the total POCP-weighted emission. The 60 VOC species include C2-C6 alkenes, C6-C8 aromatics, biogenic VOCs, and so on. The results indicated that regional scale ozone formation in the PRD region can be mainly attributed to a relatively small number of VOC species, namely isoprene, ethene, m-xylene, and toluene, etc. A further investigation of the relative contribution of the main emission source categories to ozone formation suggested that mobile sources were the largest contributor to regional O3 formation (40%), followed by biogenic sources (29%), VOC product-related sources (23%), industry (6%), biomass burning (1%), and power plants (1%). The findings obtained in this study would advance our knowledge of air quality in the PRD region, and provide useful information to local government on effective control of photochemical smog in the region. © 2010 Elsevier Ltd

Discussion: behaviour of jacked and driven piles in sandy soil

published_or_final_versio

Behaviour of jacked and driven piles in sandy soil

As an alternative to conventional dynamic pile installation methods, pile jacking is an environmentally friendly technique that could become more widely accepted. Great concern has arisen over the performance of jacked piles as compared with that of driven piles. This paper describes a comprehensive field study that was aimed at investigating the differences and similarities between the behaviour of jacked H-piles and that of driven H-piles. The instrumented piles, varying in length from 32 to 55 m and having a design capacity of up to 3540 kN, were installed in residual soils whose properties are close to silty sands. The load test results indicate that the shaft resistance of jacked piles is generally suffer and stronger than that of driven piles, but the base resistance of jacked piles is weaker than that of driven piles. At a load level of twice the design capacity, the percentage of pile head load carried by base varies from 2% to 10% for jacked piles, with a mean value of 6%; for driven piles the percentage varies from 6% to 61% with a mean value of 38%. The back-calculated values of the shaft friction coefficient, β, were found to be in a range of 0.25-0.6 for both jacked and driven piles. A correlation was also observed between the ultimate shaft friction and the mean standard penetration test N value (N̄), which suggests that the shaft friction can be taken as 1.5N̄ to 2N̄ (kPa) for both jacked and driven H-piles.published_or_final_versio

Discussion: behaviour of jacked and driven piles in sandy soil

published_or_final_versio

Role of epac in the pathogenesis of ischemic stroke

Poster Presentations: Theme 2published_or_final_version15th Research Postgraduate Symposium, Hong Kong, China, 1-2 December 2010. In Abstract - Poste Presentations (Theme II) of 15th Research Postgraduate Symposium, 2010, p. 8

Ambient CFCs and HCFC-22 observed concurrently at 84 sites in the Pearl River Delta region during the 2008–2009 grid studies

Air samples were collected concurrently at 05:00 A.M. and 10:00 A.M. local Beijing time (geomagnetic time + 8) at 84 sites during two grid-study campaigns on 29 September 2008 and 1 March 2009 in the Pearl River Delta region, in order to offer snapshots of ambient CFCs and hydrochlorofluorocarbons (HCFCs) in different seasons and to indicate the presence of local emission sources. Compared to the subtropical northern hemisphere background levels, mean mixing ratios of CFC-11, CFC-12, CFC-113, CFC-114, and HCFC-22 were enhanced by 7%–11%, 8%–11%, 5%–6%, 8%–9%, and 71%–135%, respectively. When data from this tudy were pooled together with previous observations in the region, ambient CFC-11, CFC-12, and CFC-113 unambiguously showed declines in mixing ratios, while HCFC-22 showed an increase. Spatial variations revealed potential emission hot spots in the region, and levels of CFCs and HCFC-22 were higher in September than in March due to many more refrigeration and air-conditioning activities during summer. Source apportioning by positive matrix factorization revealed that new input of CFCs and HCFC-22 into the ambient air was largely attributed to emission from air-conditioning and refrigerating activities instead of industry activities. Average emissions in the region estimated by the CO-tracer method were 0.8 ± 0.2, 1.4 ± 0.6, 0.2 ± 0.1, 0.1 ± 0.02, and 4.4 ± 1.0 Gg/yr for CFC-11, CFC-12, CFC-113, CFC-114, and HCFC-22, respectively, and they accounted for 5.5%–25.5% of the total estimated CFC and HCFC-22 emissions in China

Characterization of volatile organic compounds at a roadside environment in Hong Kong: An investigation of influences after air pollution control strategies

Vehicular emission is one of the important anthropogenic pollution sources for volatile organic compounds (VOCs). Four characterization campaigns were conducted at a representative urban roadside environment in Hong Kong between May 2011 and February 2012. Carbon monoxide (CO) and VOCs including methane (CH4), non-methane hydrocarbons (NMHCs), halocarbons, and alkyl nitrates were quantified. Both mixing ratios and compositions of the target VOCs show ignorable seasonal variations. Except CO, liquefied petroleum gas (LPG) tracers of propane, i-butane and n-butane are the three most abundant VOCs, which increased significantly as compared with the data measured at the same location in 2003. Meanwhile, the mixing ratios of diesel- and gasoline tracers such as ethyne, alkenes, aromatics, halogenated, and nitrated hydrocarbons decreased by at least of 37%. The application of advanced multivariate receptor modeling technique of positive matrix factorization (PMF) evidenced that the LPG fuel consumption is the largest pollution source, accounting for 60 ± 5% of the total quantified VOCs at the roadside location. The sum of ozone formation potential (OFP) for the target VOCs was 300.9 μg-O3 m-3, which was 47% lower than the value of 567.3 μg-O3 m-3 measured in 2003. The utilization of LPG as fuel in public transport (i.e., taxis and mini-buses) contributed 51% of the sum of OFP, significantly higher than the contributions from gasoline- (16%) and diesel-fueled (12%) engine emissions. Our results demonstrated the effectiveness of the switch from diesel to LPG-fueled engine for taxis and mini-buses implemented by the Hong Kong Special Administrative Region (HKSAR) Government between the recent ten years, in additional to the execution of substitution to LPG-fueled engine and restrictions of the vehicular emissions in compliance with the updated European emission standards

On the spatial behaviors of local mass transfer coefficients over idealized two-dimensional urban street canyons

Ref no. H14‐118Parallel Session 8 - Urban Scale and Street Canyon Modelling: Meteorology and Air QualityINTRODUCTION: Nowadays, it is no doubt that anthropogenic emission contributes a major proportion to the air pollutants in urban …postprin