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The experiments for high head airlifting performance with vertical tube were examined for wastewater treatment. Comparing with the centrifugal pump and other pumps, the airlift pump has some problems and limited applications. However, an advantage of an airlift pump is in its geometrical simplicity, not having any moving parts, so it is suitable in lifting fluids including tiny pieces of metal or grit. In this study, for the purpose of high lifting head, an air jet nozzle was used. We have performed experimentally according to various characteristics of the airlift pump system such as the change of submerged depth, lifting head of liquid-air mixture (total head) and air flow rate. This work has verified through experiments that airlift pump shows lifting ability for 3 m (Sr = 0.3) in comparison with conventional height, 2 m (Sr = 0.4). Also, we suggested that the new airlift pump system with the air booster pump be used to improve the higher lifting head performance.  相似文献   
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Abstract: Assessing species survival status is an essential component of conservation programs. We devised a new statistical method for estimating the probability of species persistence from the temporal sequence of collection dates of museum specimens. To complement this approach, we developed quantitative stopping rules for terminating the search for missing or allegedly extinct species. These stopping rules are based on survey data for counts of co‐occurring species that are encountered in the search for a target species. We illustrate both these methods with a case study of the Ivory‐billed Woodpecker (Campephilus principalis), long assumed to have become extinct in the United States in the 1950s, but reportedly rediscovered in 2004. We analyzed the temporal pattern of the collection dates of 239 geo‐referenced museum specimens collected throughout the southeastern United States from 1853 to 1932 and estimated the probability of persistence in 2011 as <6.4 × 10?5, with a probable extinction date no later than 1980. From an analysis of avian census data (counts of individuals) at 4 sites where searches for the woodpecker were conducted since 2004, we estimated that at most 1–3 undetected species may remain in 3 sites (one each in Louisiana, Mississippi, Florida). At a fourth site on the Congaree River (South Carolina), no singletons (species represented by one observation) remained after 15,500 counts of individual birds, indicating that the number of species already recorded (56) is unlikely to increase with additional survey effort. Collectively, these results suggest there is virtually no chance the Ivory‐billed Woodpecker is currently extant within its historical range in the southeastern United States. The results also suggest conservation resources devoted to its rediscovery and recovery could be better allocated to other species. The methods we describe for estimating species extinction dates and the probability of persistence are generally applicable to other species for which sufficient museum collections and field census results are available.  相似文献   
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During land transformation process in the human history,naturalized plants were introduced to several land use patterns by the different ways of plant itself .Including some naturalized plants that had been contribute to land restoration,many naturalized plants have been invaded to original habitat or landscape for native plants.Once the plants were colonized,they extend their area and population size.Urban developed areas often give an impotant role of source habitat for naturalized plants and expanding their popuation size.In recent,this tituation is appearing as one of environmental problems about the urban landscape management controlling the naturalized plants that invaded in the developed area and conserving the native vegetation.This paper is focusing on relationships between distribution of habitat of naturalized plants and landscape patch in urban area in Seoul.Gengdong-Gu ,one of the administrative areas in Seoul was selected for this study.We examined the recent land use change using LANDSAT TM data and spreading of the representative naturalized plants(Robinia pseudoacacia and Eupatorium rugosum)by Seoul Biotope Mapping Project and field survey in 1999.As a result,these two species were often occurred in the same habitat and distributed in forest edge disturbed by man.Their distribution patterns were related to landscape indices (patch size and shape)in the forest edge.  相似文献   
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