Vocational Training Council
VTC Institutional Repository (Vocational Training Council)Not a member yet
3146 research outputs found
Sort by
Biorefining waste sludge from water and sewage treatment plants into eco-construction material
No full text© 2019 Cheng, Yi, Yu, Wong, Wang, Kwon and Tsang. This study aims to investigate the feasibility of using different waste sludge and coal combustion residuals in eco-concrete block production. The compressive strength of the eco-concrete blocks produced by waterworks sludge, bottom and fly ashes were 36 MPa, which comply with the standard specifications for paving blocks in Hong Kong. The optimal mixing proportion (by weight) of different materials in the blocks, such as aggregates, cementitious materials, water, and fly ash was 1.1:1.0:0.5:0.22, respectively. The environmental and toxicological impacts of the final products were then evaluated according to the toxicity characteristic leaching procedure (TCLP). While several heavy metals (i.e., Hg, Cu, and Pb) have been identified in the specimens, the levels of these contaminants complied with Standards (US 40 CFR 268.48). Waste materials generated from water and sewage treatment processes and power plants are feasible to be used as ingredients for paving concrete block production. These products are environmentally acceptable and mechanically suitable for resource recovery of waste materials
Co-designing Mobile Collection Points with Older Persons to Promote Green Attitudes and Practices in Hong Kong
No full textEconomic sustainability of heritage conservation in Hong Kong: The impact of heritage buildings on adjacent property prices
Get PDFInformed by the theoretical framework of sustainable development and economic theories including the cluster theory and the corollary of the Coase Theorem, this paper empirically investigates the economic impact of architectural heritage in Hong Kong. Using the hedonic price model, the research examines the economic impact of 50 publicly owned versus 50 privately owned heritage buildings on adjacent residential property prices with a sample size of over 43,240 property transaction records spanning a time period of 10 years. The research supports that heritage conservation can promote economic sustainability aside from cultural sustainability and social engagement. This research benefits government policymakers, urban planners, architects, and heritage conservationists by contributing new knowledge to the studies on sustainable urban development, heritage conservation, and cultural economics
Fuel consumption and emissions performance under real driving: Comparison between hybrid and conventional vehicles.
No full textHybrid electric vehicles (HEVs) are perceived to be more energy efficient and less polluting than conventional internal combustion engine (ICE) vehicles. However, increasing evidence has shown that real-driving emissions (RDE) could be much higher than laboratory type approval limits and the advantages of HEVs over their conventional ICE counterparts under real-driving conditions have not been studied extensively. Therefore, this study was conducted to evaluate the real-driving fuel consumption and pollutant emissions performance of HEVs against their conventional ICE counterparts. Two pairs of hybrid and conventional gasoline vehicles of the same model were tested simultaneously in a novel convoy mode using two portable emission measurement systems (PEMSs), thus eliminating the effect of vehicle configurations, driving behaviour, road conditions and ambient environment on the performance comparison. The results showed that although real-driving fuel consumption for both hybrid and conventional vehicles were 44%–100% and 30%–82% higher than their laboratory results respectively, HEVs saved 23%–49% fuel relative to their conventional ICE counterparts. Pollutant emissions of all the tested vehicles were lower than the regulation limits. However, HEVs showed no reduction in HC emissions and consistently higher CO emissions compared to the conventional ICE vehicles. This could be caused by the frequent stops and restarts of the HEV engines, as well as the lowered exhaust gas temperature and reduced effectiveness of the oxidation catalyst. The findings therefore show that while achieving the fuel reduction target, hybridisation did not bring the expected benefits to urban air quality
Year-round-based optimization of high-low control in the regenerative indirect evaporative cooler (RIEC)
No full textThe performance of the regenerative indirect evaporative cooler (RIEC) highly depends on ambient temperature and humidity. To maintain indoor thermal comfort, proper control strategy is essential. Previous research indicates that high–low (H-L) control by using multispeed technology is superior to the conventional on–off control in terms of energy consumption and thermal comfort. Under H-L control, a fan switches between a high speed and a low speed. The high speed is determined by the peak load. However, the selection of low speed involves a great sense of subjectivity. Therefore, the influence of low speed on system performance is comprehensively investigated and an optimal low speed to high speed ratio (L/H) is determined. An optimization method is proposed by considering annual energy consumption, predicted mean vote, temperature fluctuation, and switch frequency of fan speed. Case studies have been conducted in some typical hot and arid regions. The results show that better thermal comfort can be provided under lower L/H from the aspects of high control precision and low temperature fluctuation. The switch frequency of fan speed and the annual energy consumption first decrease and then increase with the increment of L/H. The optimal L/H is between 0.2 to 0.3 from a year-round perspective and with comprehensive consideration
Species diversity and spatial pattern of old and precious trees in Macau
No full textThe world\u27s fast pace of urbanization has exerted profound pressure on urban trees. With over 400 years of urban history, Macau has developed an exceptionally high population density and ultra-compact mode, yet it permits survival of interesting and diverse heritage trees. These outstanding living remnants connote special values in history, ecology and botany. In conjunction with commemorative importance, they have been designated as Old and Precious Trees (OPT). This study evaluated the OPT with reference to: (a) species diversity and evenness; (b) spatial distribution; (c) tree dimensions, age and health; and (d) spatial differentiation of tree attributes by four districts and eight tree-habitats. Heritage trees in Macau were compared with those in Hong Kong and Guangzhou. The 793 OPT belong to 63 species. The exotic Ficus rumphii is overwhelmingly dominant, followed by F. microcarpa, Cinnamomum camphora and Dimocarpus longan. Species composition, age distribution and health conditions are associated with tree-habitat. Roadside has the largest number of OPT but the least species richness. Public parks and gardens has the highest diversity and largest tree dimensions. The oldest trees are clustered in urban parks and religious places. Tree health is poorer at roadsides, and private residential and commercial properties. The patterns suggest close relationship between tree traits and physical fabric of the city. However, the variety rather than duration of geographical contacts is a key determinant of urban tree diversity. The findings offer insights for heritage-tree conservation and management strategies in compact cities with similar urban structure and history. Copyright © 2017 Elsevier B.V. All rights reserved
Is fine dining dying? 高級餐飲輓歌高唱？
Get PDFStarched linens, portentous waiters and three-month waiting lists are no longer the automatic hallmarks of haute cuisine. With restaurants offering bar seating, no reservations and sharing plates, and removing airs and graces from the high-end eating experience, can the old guard survive the casual fine dining revolution?
高級餐廳不再等同於平滑無縐的枱布、高傲的侍者和長達三個月的訂座名單。吧枱座位、無需訂座、共用餐桌的休閒高級餐廳的興起，會否令氣氛拘謹的傳統高級餐廳奏起輓歌
