Development of a limit state approach for design against gas explosions

The design of topsides against explosions requires the definition of a design over-pressure, however, these values are often treated as deterministic and there is a wide variation within the industry in the treatment and interpretation of the loads.

This paper advocates the adoption of a number of limit state for explosion loading. Events of different magnitudes are differentiated on the basis of frequency and linked to appropriate degree of reliability thus avoiding disproportionate effects from minor events.

The two principal limit states considered are a limit state for all the safety critical systems for relatively high frequency events and a survival condition for low probability events. Parallels are drawn from other branches of engineering where extreme loads have to be designed for.     

Delayed juvenile dispersal and monogamy, but no cooperative breeding in white-breasted mesites (Mesitornis variegata)

Although cooperative breeding is known from only about 9 % of bird species, it has received substantial attention because individuals foregoing their own reproduction to help others represent a long-standing evolutionary puzzle. We studied group formation, breeding system, spatial distribution and several life-history traits of white-breasted mesites (Mesitornis variegata). Based on field observations across 3 years, we found that white-breasted mesites live in year-round stable pairs, and that groups are formed by juvenile philopatry. As other family-living birds, M. variegata exhibit a slow pace-of-life, characterized by high annual adult survival, low productivity, long chick dependence and extended parental care. However, although reproduction is monogamous and juveniles showed interest in their parents’ nests, we found no evidence of cooperative breeding. We suggest that slow life-histories, extended parental care and year-round territoriality predispose juvenile mesites to delay dispersal. However, adult intolerance toward older juveniles may prevent them from adopting a cooperative lifestyle. Comparisons with other species of mesite indicate that monogamy and delayed juvenile dispersal are necessary, but not sufficient for the evolution of cooperative breeding in this family of birds, and that particular ecological and social conditions have facilitated the transition from pair-living to a type of group that may represent a stepping stone in the evolution of cooperative breeding in mesites and other birds.     

Recovery studies of selenium using dry ashing procedure with ashing aid.

A previously reported dry ashing procedure for the decomposition of marine samples prior to arsenic determination is demonstrated to be equally applicable to the analysis of selenium. Quantitative recovery of selenium as inorganic or organic compounds in a variety of plants and animal tissues is demonstrated using 75Se tracer and X-ray fluorescence techniques. The dry ashing procedure is simpler than the official AOAC method, which uses a mixture of H2SO4, HNO3 and HC10(4).     

Wastewater nutrient removal by Chlorella pyrenoidosa and Scenedesmus sp

Two different species of photosynthetic microalgae, Chlorella pyrenoidosa and Scenedesmus sp., were grown in settled and activated sewage filtrates at two different inoculum sizes, aimed to reduce nutrient load from wastewater. Higher growth rates were recorded in cultures with higher inoculum size, and algal cells usually grew better in settled sewage than in activated sewage. As algae started to grow and multiply, both nitrogen and phosphorus content in wastewater decreased significantly. The removal rate was rapid during the first week of growth and more than 2/3 of wastewater N and P was reduced. After the initial period, the removal rate slowed down. At the end of this study, more than 80% of total-P and inorganic N present in settled sewage were reduced but such removal efficiency was lower in activated sewage. In general, high inoculum size of algal cells provided more N and P removal than low inoculum, and Chlorella cells performed better than Scenedesmus. These results suggest that cultivation of Chlorella seems to be one of the feasible methods to reduce the amount of nitrogen and phosphorus entering the nearby coastal water, thus preventing the eutrophication problem. It is also clear that algal ponds with high inoculum size might be more suitable to be installed as a secondary rather than a tertiary treatment process.     

How environmental management driving forces affect environmental and economic performance of SMEs: a study in the Northern China district

Small- and medium-sized enterprises (SMEs) form the core of societal and economic development. However, most people query on the implementation and performance of environmental management. In this paper, the manufacturing SMEs in Northern China with different pollution levels are studied to explore the main forces (e.g., government, society, market, and enterprise itself) driving SMEs for promoting environmental management. It focuses on the correlation between environmental management and economic performance for SMEs at different pollution levels. The results show that SMEs of different pollution levels have significant differences in the relationship of driving forces and performance. First, for SMEs with high-pollution levels, social and market driving forces and government incentives are revealed having a significant effect on their environmental performance. Driving forces from within the enterprise itself and the market provide a positive effect on the economic performance, while social forces have a negative effect. Second, for SMEs with light pollution, social and market driving forces, and government assistance play a supporting role on corporate environmental performance improvement. It is also found that the driving force of the enterprise itself does not have a significant effect on the environmental performance for SMEs with different pollution levels. In addition, the environmental performance and economic performance for SMEs with high or light-pollution levels are positively correlated. Further, it shows that the environmental performance is moderately correlated with financial indices, but not significantly with the non-financial indices.     

Assessment of climate change vulnerability of tourism in Hungary

This paper applies vulnerability assessment methodology to assess the comparative vulnerability of different tourism supply types by region in Hungary. The steps of the methodology include (1) definition of tourism supply typology, (2) identifying exposure indicators, (3) identifying sensitivity indicators, (4) identification of adaptive capacity indicators and (5) developing a vulnerability map. It is clear that climate change has potential negative effects on tourism in Hungary, but the spatial distribution, as well as the sub-sectoral (by tourism supply types) differences of these impacts is almost unknown. Most research papers dealing with the vulnerability of tourism mainly focus on a specific tourism type, whereas this article aims to address all of them from a regional point of view. The key results presented in this paper include the vulnerability map of the country showing the relative vulnerability of different tourism supply types and detailed analysis investigating the possible causes and driving factors. We have categorized tourism regions based on the five most vulnerable tourism supply types. The most significant of them all turned out to be outdoor event-based tourism, being the most vulnerable in the two southern regions, since the expected impacts of climate change are foreseen to be the most significant in these areas.     

Insect herbivores, density dependence, and the performance of the perennial herb Solanum carolinense

How insect herbivores affect plant performance is of central importance to basic and applied ecology. A full understanding of herbivore effects on plant performance requires understanding interactions (if any) of herbivore effects with plant density and size because these interactions will be critical for determining how herbivores influence plant population size. However, few studies have considered these interactions, particularly over a wide enough range of densities to detect nonlinear effects. Here we ask whether plant density and herbivores influence plant performance linearly or nonlinearly, how plant density affects herbivore damage, and how herbivores alter density dependence in transitions between plant size classes. In a large field experiment, we manipulated the density of the herbaceous perennial plant Solanum carolinense and herbivore presence in a fully crossed design. We measured plant size, sexual reproduction, and damage to plants in two consecutive years, and asexual reproduction of new stems in the second year, allowing us to characterize both plant performance and rates of transition between plant size classes across years. We found nonlinear effects of plant density on damage. Damage by herbivores and plant density both influenced sexual and asexual reproduction of S. carolinense; these effects were mostly mediated via effects on plant size. Importantly, we found that herbivores altered the pattern of linear density dependence in some transition rates (including survival and asexual reproduction) between plant size classes. These results suggest that understanding the ecological or evolutionary effects of herbivores on plant populations requires consideration of plant density and plant size, because feedbacks between density, herbivores, and plant size may complicate longer-term dynamics.     

Agriotes proximus and A. lineatus (Coleoptera: Elateridae): a comparative study on the pheromone composition and cytochrome c oxidase subunit I gene sequence

The presence of geranyl octanoate, previously found in pheromone gland extracts of Agriotes lineatus females, was also demonstrated in gland extracts of A. proximus females. Similar to A. lineatus, geranyl butanoate was present only in trace amounts in A. proximus female gland extracts. In air entrainment samples of female A. lineatus and A. proximus beetles, the relative ratio of geranyl butanoate and geranyl octanoate was higher than that in gland extracts. In addition, comparison of a segment of the mitochondrial cytochrome c oxidase subunit I gene of feral specimens of A. lineatus and A. proximus showed >99% similarity. Both pheromone profile and nucleotide sequence analysis delineate close relationship between the investigated taxa and postulate taxonomic revision. Further studies on sympatric populations of A. lineatus and A. proximus are underway to investigate and better understand possible processes of species diversification.     

Size dependent cytotoxicity of fly ash particles

Fly ash samples were collected from the electrostatic precipitator of a coal-fired power plant in Hong Kong. The particles of the respirable range (smaller than 10 μm) were divided into 4 groups according to their particle size (mass median aerodynamic diameters). The surface morphology and the metal contents (Fe, Mn, Al and Zn) of fly ash particles were examined by a scanning electron microscope and an inductively coupled plasma spectrophotometer, respectively. The particles were very heterogenous in size and shape as well as the concentration of metals. The cytotoxicity of these four groups of fly ash particles was evaluated using an in vitro rat alveolar macrophages culture assay. The viability of alveolar macrophages was lower when incubated with smaller size particles. This relationship was also reflected by the damage of the surface morphology of the cells and the release of cytoplasmic (lactate dehydrogenase) and lysosomal (acid phosphatase and β-glucuronidase) marker enzymes into the culture media.