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51.
Byung Kyu Kim Dedy Ng Ray A. Mentzer M. Sam Mannan 《Journal of Loss Prevention in the Process Industries》2013,26(6):1670-1678
Concerns over public safety and security of a potential liquefied natural gas (LNG) spill have promoted the need for continued improvement of safety measures for LNG facilities. The mitigation techniques have been recognized as one of the areas that require further investigation to determine the public safety impact of an LNG spill. Forced mitigation of LNG vapors using a water curtain system has been proven to be effective in reducing the vapor concentration by enhancing the dispersion. Currently, no engineering criteria for designing an effective water curtain system are available, mainly due to a lack of understanding of the complex droplet–vapor interaction. This work applies computational fluid dynamics (CFD) modeling to evaluate various key design parameters involved in the LNG forced mitigation using an upwards-oriented full-cone water spray. An LNG forced dispersion model based on a Eulerian–Lagrangian approach was applied to solve the physical interactions of the droplet–vapor system by taking into account the various effects of the droplets (discrete phase) on the air–vapor mixture (continuous phase). The effects of different droplet sizes, droplet temperatures, air entrainment rates, and installation configurations of water spray applications on LNG vapor behavior are investigated. Finally, the potential of applying CFD modeling in providing guidance for setting up the design criteria for an effective forced mitigation system as an integrated safety element for LNG facilities is discussed. 相似文献
52.
Jelle S. van Zweden Christoph Grüter Sam M. Jones Francis L.W. Ratnieks 《Behavioral ecology and sociobiology》2011,65(6):1277-1282
Social insects need to defend their nest against robbery, parasitism and predation. The stingless bee Tetragonisca angustula is unique in that it has guards that hover near the nest entrance in addition to guards that stand at the entrance. We tested
both the general hypothesis that hovering guards increase the effectiveness with which flying intruders are detected and the
specific hypothesis that hovering guards improve the detection of workers of the obligate robber bee, Lestrimellita limao. In an intraspecific study comparing colonies, we found a strong positive relationship between the number of hovering guards
and the distance at which a dummy robber bee or L. limao worker, experimentally moved towards the nest entrance, was detected. These results were mirrored in an interspecific study
showing that four species of stingless bees with similar population colonies but which lacked hovering guards, detected L. limao only at the nest entrance, in contrast to T. angustula. In addition, we found that a greater number of attacks by guards occurred when dummies were impregnated with citral, a major
component of L. limao mandibular gland odour. Our results support the hypothesis that T. angustula hovering guards increase the detection perimeter for flying intruders, especially L. limao. 相似文献
53.
Sam Provoost M. Laurence M. Jones Sally E. Edmondson 《Journal of Coastal Conservation》2011,15(1):207-226
In coastal dunes, landscape changes are a rule, rather than an exception. This paper gives an overview of changes in landscape
and vegetation with a focus on the past century. The history of dunes is characterised by phases of sand drift, alternated
with geomorphological stability. The historical development of dune woodland during these stable phases has been documented
for sites all over Europe. Vegetation reconstructions of historical open dune habitats however is very difficult due to limited
preservation of fossil remains. People have drastically altered coastal dune landscapes through centuries of exploitation
and more recently development of the coast. Historical land use has generally pushed vegetation back into a semi-natural state.
During roughly the past century a tendency of increasing fixation and succession is observed on coastal dunes throughout northwest
Europe. Six causes of change are discussed. 1) Changes in land use, mainly abandonment of agricultural practices, have led
to the development of late successional stages such as scrub and woodland. 2) Crashing rabbit populations due to myxomatosis
in the 1950s caused vigorous grass growth and probably stimulated scrub development. 3) A general tendency of landscape fixation
is observed due to both natural and anthropogenic factors. 4) Eutrophication, mainly due to atmospheric nitrogen deposition
is clearly linked to grass encroachment on acidic but also on some calcareous dunes. 5) The impact of climate change on vegetation
is still unclear but probably lengthening of growing season and maybe enhanced CO2 concentrations have led to an acceleration of succession. 6) A general anthropogenisation of the landscape occurs with rapid
spread of non-native species as an important consequence. The reconstruction of a natural reference landscape is considered
largely unattainable because of irreversible changes and the long tradition of human impact, in many cases since the development
of the dunes. Two contradictory elements need reconciliation. First, the general acceleration of succession and scrub and
woodland development in particular is partly caused by a decreased anthropogenic interference in the landscape and deserves
more appreciation. Second, most biodiversity values are largely linked to open, early succession dune habitats and are threatened
by the same tendency. Apart from internal nature management, in which grazing plays an important part, re-mobilisation of
stable, senescent dunes is an important challenge for dune management. 相似文献
54.
Sam Godfrey Pawan Labhasetwar Satish Wate Sarika Pimpalkar 《Environmental monitoring and assessment》2011,176(1-4):561-574
The World Health Organization (WHO)/United Nations Children??s Fund (UNICEF) Joint Monitoring Programme (JMP) for Water Supply and Sanitation was designed to provide reference figures for access in individual countries to safe water. The JMP is based on non-administrative or nongovernment data from national-level surveys such as the Multiple Indicator Clusters Survey (MICS) or Demographic Health Survey. In the 2007 JMP report, India is noted to have water supply coverage of 89% (95% in urban areas and 85% in rural areas) compared to the Government of India estimates of 95%. The central state of Madhya Pradesh is noted by the Government of India to have coverage of 60%. However, the definition of access to safe water currently does not consider the quality or safety of the water being consumed. This paper, therefore, presents results from the application of a statistical tool (random multiple cluster technique??termed Rapid Assessment of Drinking Water Quality [RADWQ]) to Indore Zone in Madhya Pradesh. When results provided by the RADWQ technique are compared to the JMP MICS data, coverage levels reported in the JMP are reduced by up to 40% due to the high risk of microbiological (thermotolerant coliforms) contamination. In Indore Zone, the coverage of safe water reduced from 42% to 25% through the inclusion of the water safety parameters. The study recommends the inclusion of water quality/safety data in reported data under the UNICEF/WHO JMP. 相似文献
55.
Contrary to much boundary spanning research, we examined the negative consequences of boundary spanning contact in multi‐organizational contexts. Results from a sample of 833 Dutch peacekeepers show that employees' boundary spanning contact with members of other organizations was associated with reports of negative relationships with external parties (e.g., work‐specific problems, culture‐specific problems). These negative relationships also had a spillover effect such that they mediated the effect of boundary spanning contact on boundary spanners' negative attitudes toward their own jobs and organization (e.g., job attractiveness and confidence in the organization). Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
56.
Tae Won Lee Michael J. Miller Hak Bin Hwang Sam Wouthuyzen Katsumi Tsukamoto 《Marine Biology》2008,153(3):285-295
Leptocephali of the widely distributed tropical marine eels of the genus Kaupichthys (family Chlopsidae) were collected around Sulawesi Island during a sampling survey in the Indonesian Seas in late September
and early October 2002, and the otolith microstructure of 24 of the 59 specimens captured was examined to learn about the
larval growth rates and spawning times of these small sized eels. Leptocephali ranging in size from 25 to 60 mm were collected
in Makassar Strait and the Celebes Sea, but they were most abundant in the semi-enclosed Tomini Bay of northeast Sulawesi
Island. The Kaupichthys leptocephali examined had 39–161 otolith growth increments. Their back-calculated hatching dates indicated that five age
groups were present and each group appeared to have been spawned around the full moon of previous months. Average growth rate
estimates of the first two age groups were 0.65 and 0.54 mm/day for the 27.4–30.4 and 37.6–45.6 mm age classes. The growth
rates of the oldest three age groups (52.0–60.8 mm) appeared to have slowed down after they reached their approximate maximum
size. An increase in increment widths at the outer margin of the otoliths of those larger than 53 mm suggested that the process
of metamorphosis had begun even though there were few external morphological changes indicating metamorphosis. It is hypothesized
that chlopsid leptocephali have an unusually short gut that may not need to move forward during early metamorphosis. The presence
of four age classes in Tomini Bay suggests that the Togian Islands region may be productive habitats for Kaupichthys juveniles and adults. 相似文献
57.
Gorsevski PV Donevska KR Mitrovski CD Frizado JP 《Waste management (New York, N.Y.)》2012,32(2):287-296
This paper presents a GIS-based multi-criteria decision analysis approach for evaluating the suitability for landfill site selection in the Polog Region, Macedonia. The multi-criteria decision framework considers environmental and economic factors which are standardized by fuzzy membership functions and combined by integration of analytical hierarchy process (AHP) and ordered weighted average (OWA) techniques. The AHP is used for the elicitation of attribute weights while the OWA operator function is used to generate a wide range of decision alternatives for addressing uncertainty associated with interaction between multiple criteria. The usefulness of the approach is illustrated by different OWA scenarios that report landfill suitability on a scale between 0 and 1. The OWA scenarios are intended to quantify the level of risk taking (i.e., optimistic, pessimistic, and neutral) and to facilitate a better understanding of patterns that emerge from decision alternatives involved in the decision making process. 相似文献
58.
Ram Kailash P. Yadav Efimia M. Papatheodorou Katerina Karamanoli Helen-Isis A. Constantinidou Despoina Vokou 《Chemoecology》2008,18(4):217-226
Summary. We studied the epiphytic bacterial communities of the summer leaves of eight perennial species naturally occurring in a Mediterranean
ecosystem. The species differ in essential-oil content (from rich in essential oil to non-producers) and composition, and
also in life form (from herbaceous species to tall shrubs). We compared the epiphytic bacterial communities on the basis of
(i) their abundance, (ii) their metabolic profile (derived by use of the BIOLOG Ecoplate system) and (iii) richness and diversity
of substrates that they use, as a measure of functional diversity. Among all species, the aromatic Melissa officinalis was the most abundantly colonized. The bacterial communities on the leaves of the aromatic Myrtus communis, Calamintha nepeta and Melissa officinalis, and also of Cistus incanus catabolized all 31 substrates offered; those on the evergreen-sclerophyllous species, Arbutus unedo and Quercus coccifera, catabolized only 14 and 17 substrates, respectively. Carbohydrates were consistently used abundantly by all communities,
whereas carboxylic acids were most variably used. On average, the group of aromatic plants scored higher regarding bacterial
abundance, and richness and diversity of substrates used by the bacterial communities on their leaves; the lowest values for
both substrate-use indices were recorded in A. unedo. Bacterial abundance or richness or diversity of substrates used did not vary with leaf oil content. Abundance was positively
correlated with both substrate-use indices. Results support claims that the antimicrobial effects of essential oils are not
exerted so much under natural conditions as reports based on biassays with pathogens usually show. Although essential oils
play a part in the microbial colonization of the phyllosphere, it is not likely that inhibition of phyllosphere bacteria is
essential oils’ primary role, at least in the Mediterranean environment. 相似文献
59.
60.