Changes in energy intensiveness of Hong Kong economy, 1995–2007

The growth of Primary Energy Requirements (PER) slackened appreciably since the late 1990s in Hong Kong while Final Energy Requirements (FER) actually declined. Yet GDP continued to grow at a respectable average annual growth rate during the period, leading to a drastic drop in the energy intensiveness of the economy. The article analyzed the factors that contributed to the emergence of the above phenomena and discussed its consequences.     

Vacuum-tight sample transfer stage for a scanning electron microscopic study of stabilized lithium metal particles

A vacuum-tight transfer stage is described, that enables air or moisture sensitive specimens to be safely transferred from a protective environment, like that in a dry box, to a scanning electron microscope without exposing the sample to ambient conditions. The transfer stage concept described here is, in fact, applicable to the protected transfer of hygroscopic or air-sensitive samples to any vacuum-based analysis equipment where the transfer device opens automatically under vacuum to reveal the sample. This device concept is also applicable to the transfer of samples under vacuum from one glove box to another where the transfer chamber can be easily opened manually to reveal the sample. An example of one application of the device is provided by a controlled exposure study of stabilized lithium metal particles (SLMP) at various stages of shelf life. We found that a reaction coating formed on “fresh” SLMP after it was exposed to 100 Pa air for as short as 15 m. Such a reaction to air exposure was not observed on “aged” SLMP with a thickened carbonate surface coating after 4 and 6 months of shelf life. The case study of the surface coating on SLMP clearly demonstrated the excellent vacuum performance of the novel transfer stage.     

Measured effect of airflow and refrigerant charge on the seasonal performance of an air-source heat pump using R-410A

The objective of this study was to measure the effects of improper airflow and refrigerant charge on the seasonal performance of a typical 10.6 kW, R-410A residential heat pump with a thermostatic expansion valve.Heating and cooling tests were performed in combinations of three refrigerant charges of 75%, 100%, and 125% of nominal value and two airflows of 75% and 100% of rated airflow. In addition, cyclic tests were performed to estimate the heating and cooling seasonal coefficient of performance (COP) at six climate zones specified by Air-Conditioning, Heating, and Refrigeration Institute (AHRI) Standard 210/240-2008. Results showed that, in each climate zone, increases in refrigerant charge at the rated airflow could improve the unit's heating seasonal COP by as much as 5%. However, combined decreases in airflow and refrigerant charge could penalize the unit's heating seasonal COP by as much as 10%.     

Integrated Development Planning in South Africa: Lessons from the Dwars River Valley

Post-apartheid South Africa has brought about internationally acclaimed legislation that promotes social equity and environmental sustainability. This paper presents findings of research conducted in the Municipality of Stellenbosch on the effectiveness of the participatory planning model, the Integrated Development Plan (IDP). While post-apartheid accomplishments are noteworthy, power dynamics and fiscal insecurity continue to shape outcomes. Innovative coalitions have emerged, instilling hope that true participation is possible after trust between all stakeholders mends historical tensions.     

Loggerhead sea turtle (Caretta caretta) egg yolk concentrations of persistent organic pollutants and lipid increase during the last stage of embryonic development

Data are scarce describing the concentrations of polychlorinated biphenyls (PCBs) and organochlorine pesticides in sea turtle eggs. The purpose of this study was to establish appropriate sample collection methodology to monitor these contaminants in sea turtle eggs. Contaminant concentrations were measured in yolk samples from eggs that failed to hatch from three loggerhead sea turtle (Caretta caretta) nests collected in southern Florida to determine if concentrations change through embryonic development. One to three egg yolk samples per nest were analyzed from early, middle, and late developmental stages (n=22 eggs total). PCB and pesticide concentrations were determined by gas chromatography with electron capture detection (GC-ECD). Geometric mean concentrations of summation operatorPCBs (52 congeners), summation operatorDDTs, summation operatorchlordanes, and dieldrin in all eggs were 65.0 (range=7.11 to 3930 ng/g lipid), 67.1 (range=7.88 to 1340 ng/g lipid), 37.0 (range=4.04 to 685 ng/g lipid), and 11.1 ng/g lipid (range=1.69 to 44.0 ng/g lipid), respectively. Early and middle developmental stage samples had similar concentrations of PCBs and organochlorine pesticides on a wet-mass basis (ng/g tissue extracted), but the concentrations doubled by the late stage. This increase is most likely attributable to the 50% increase in lipid content observed in the late-stage yolk. These findings indicate that an early-stage sample cannot be directly compared to a late-stage sample, especially from different nests. These preliminary findings also allowed us to calculate the minimum number of eggs per nest required for analysis to obtain an acceptable mean concentration per nest. More research is required to investigate geographical trends of contaminant concentrations and potential health effects (i.e., abnormalities) caused by these contaminants on sea turtle development.     

Chronic toxicity of hydrogen peroxide to Daphnia magna in a continuous exposure, flow-through test system

A flow-through, continuous exposure test system was developed to expose Daphnia magna to an unstable compound. 35% Perox-Aid is a specially formulated hydrogen peroxide (a highly oxidative chemical) product approved for use in U.S. aquaculture and therefore has the potential to be released from aquaculture facilities and pose a risk to aquatic invertebrates. The study objective was to assess the effects of 35% Perox-Aid on an aquatic invertebrate by evaluating the survival, growth, production, and gender ratio of progeny from a representative aquatic invertebrate continuously exposed to 35% Perox-Aid. The study design consisted of 6 treatment groups (10 test chambers each) with target hydrogen peroxide concentrations of 0.0, 0.32, 0.63, 1.25, 2.5, and 5.0 mg L(-1). The study was initiated with <24-h-old Daphnia (1 daphnid per chamber) that were exposed to hydrogen peroxide for 21 days. Hydrogen peroxide concentrations < or =1.25 mg L(-1) had no significant effect on Daphnia time to death compared to controls and no significant effect on the time to first brood production and the number of broods produced. Concentrations < or =0.63 mg L(-1) had no significant effect on the total number of young produced. Concentrations > or =0.32 mg L(-1) had a negative effect on Daphnia growth. Hydrogen peroxide had no significant effect on the gender ratio of young produced. All second generation Daphnia were female. A continuous discharge of hydrogen peroxide into aquatic ecosystems is not likely to affect cladocerans if the concentration is maintained at < or =0.63 mg L(-1) for less than 21 days.     

Serum PCB profiles in Native Americans from Wisconsin based on region, diet, age, and gender: Implications for epidemiology studies

BACKGROUND: Different PCB congeners and different mixtures of congeners have been demonstrated to have different biological actions. More complete characterization of congener profiles in exposure sources may assist in predicting health outcomes. METHODS: Thirty-six (36) polychlorinated biphenyl (PCB) congeners were measured by gas chromatography isotope-dilution mass spectrometry (IDMS) in 314 serum samples from Native Americans in Wisconsin, Michigan and Minnesota. Five dietary groups were established based on the quantity and species of fish consumed and the waters from which the fish were caught. Multivariate statistical methods were able to resolve gender and dietary differences in PCB homologue and PCB congener patterns. RESULTS: Females had higher proportions of lower chlorinated homologues, including a consistently higher proportion of pentaCB 118. The relative presence of the very labile and volatile PCB 18, above 1% of the total PCB in females from the minimal fish consumption and "other" groups, suggests possible exposure to PCBs in the atmosphere. The dietary group consuming predatory fishes from Lakes Michigan and Superior had the highest serum concentrations of total PCB (mean of 3.1 ng/ml) and the most distinct congener profile. The two dietary groups least dependent on fishing or fishing mostly from inland lakes (non-Great Lakes) had the lowest total PCB concentrations, both with means of 1.4 ng/ml. CONCLUSIONS: These serum PCB concentrations were less than those found in earlier studies of fish consumers in the Great Lakes region and may reflect the decrease in PCBs in these lakes.     

Service life prediction

A joint committee of CIB and RILEM has produced a report which analyses the shortcomings of much ‘durability’ testing, identifies the problems facing reliable service life prediction, offers a methodology for approaching those problems and lists the key research needs. The report is reviewed here by the committee co‐ordinator, who also gives his version of the ‘Ten Commandments’ for service life prediction.     

Brave New Worlds: Reaching Towards a New Era of Space Architecture

Space travel is on the brink of a new era. Larry Bell , Professor of Architecture and Space Architecture at the University of Houston, describes how new ambitions are being reached for, such as the exploration of distant Mars, which will require longer and ever more complex missions. At the same time Space is being opened up internationally, with the participation of China and India, and space tourism is introducing privatisation and new commercial players.     

Laser densification of alumina powder beds generated using aerosol assisted spray deposition

Layered manufacturing involves a range of techniques in which objects can be constructed in a laminated form. Therefore, the deposition technique is a critical part of direct-layered fabrication technologies. In this paper, aerosol assisted spray deposition has been applied to generate spraying of a suspension to prepare powder beds for subsequent selective laser sintering. First, an investigation on preparation of the alumina suspension by adding polyacrylic acid dispersant is presented. An emphasis has been given to identify the most effective dispersant to enhance the dispersibility of alumina suspension for aerosol spraying deposition. Subsequently, a laser has been used to selectively densify the alumina powder beds to produce ceramics. The effects of the laser processing parameters such as scanning speed, power and beam size on the microstructural evolution of the powder beds are investigated and discussed. Also, a laser densification mechanism is also proposed and discussed.