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Jong-Kuk ChoiHyun-Joo Oh Bon Joo KooJoo-Hyung Ryu Saro Lee 《Ecological modelling》2011,222(8):1522-1533
To make a macrofaunal (crustacean) habitat potential map, the spatial distribution of ecological variables in the Hwangdo tidal flat, Korea, was explored. Spatial variables were mapped using remote sensing and a geographic information system (GIS) combined with field observations. A frequency ratio (FR) and logistic regression (LR) model were employed to map the macrofauna potential area for the Ilyoplax dentimerosa, a crustacean species. Spatial variables affecting the tidal macrofauna distribution were selected based on abundance and biomass and used within a spatial database derived from remotely sensed data of various types of sensors. The spatial variables included the intertidal digital elevation model (DEM), slope, distance from a tidal channel, tidal channel density, surface sediment facies, spectral reflectance of the near infrared (NIR) bands and the tidal exposure duration. The relation between the I. dentimerosa and each spatial variable was calculated using the FR and LR. The species was randomly divided into a training set (70%) to analyse habitat potential using FR and LR and a test set (30%) to validate the predicted habitat potential map. The relations were overlaid to produce a habitat potential map with the species potential index (SPI) value for each pixel. The potential habitat maps were compared with the surveyed habitat locations such as validation data set. The comparison results showed that the LR model (accuracy is 85.28%) is better in prediction than the FR (accuracy is 78.96%) model. The performance of models gave satisfactory accuracies. The LR provides the quantitative influence of variables on a potential habitat of species; otherwise, the FR shows the quantitative influence of a class in each variable. The combination of a GIS-based frequency ratio and logistic regression models and remote sensing with field observations is an effective method to determine locations favorable for macrofaunal species occurrences in a tidal flat. 相似文献
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Youn-Suk Son Jae-Sik Jeon Hyung Joo Lee In-Cheol Ryu 《Journal of the Air & Waste Management Association (1995)》2014,64(9):1054-1061
In this study, variations of particulate matter (PM) concentrations in subway trains following installation of platform screen doors (PSDs) in the Seoul subway system were investigated. PM samples were collected in the trains on subway lines 1–8 before and after installation of PSDs. It was found that the mean PM10 concentration in the trains after PSDs installation increased significantly by 29.9% compared to that before installation. In particular, the increase of PM10 in line 6 was the highest at 103%. When the relationship between PM10 and PM2.5 was compared, coefficients of determination (r2) before and after PSDs installations were 0.696 and 0.169, respectively. This suggests that air mixing between the platform and the tunnel after PSDs installation was extremely restricted. In addition, the indoor/outdoor PM10 ratio following PSDs installation increased from 1.32 to 2.97 relative to the period with no installed PSDs. Furthermore, this study revealed that PM levels in subway trains increased significantly after all underground PSDs were put in use. Several potential factors were examined that could result in this PM increase, such as train ventilation systems, operational conditions, passenger volume, subway depth, and the length of underground segments.
ImplicationsPM10 concentrations inside the subway trains increased after PSDs installation. This indicates that air quality in trains was very seriously impacted by PSDs. PM10 levels were also influenced by the tunnel depth and length of the underground segments. To prevent the adverse effect on human health by PM10 emitted from the tunnel, an applicable ventilation system to reduce PM10 is required inside trains and tunnels. 相似文献
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Yong-Woon Lee Changkook Ryu Woong-Jin Lee Young-Kwon Park 《Journal of Material Cycles and Waste Management》2011,13(3):165-172
Wood pellet is a densified fuel with homogeneous physical properties suitable for use at various scales in domestic and industrial
furnaces. A wood pellet stove is a small-scale furnace for domestic heat production that can replace conventional oil or gas
boilers. Since the fuel properties of wood pellet are very different from those of oil or gas, the design of a wood pellet
stove requires profound understanding of solid fuel combustion as well as of gas flow mixing and reactions. Due to limitations
on the height of an installed furnace (~1 m), poor design of the furnace, air supply, fume extraction, or the heat exchanger
may lead to excessive CO emissions or low energy efficiency. This study evaluated the design of an existing wood pellet stove
with 30,000 kcal/h capacity, using experimental and computational techniques in order to optimize the furnace design. The
results show that it is critical to minimize unused furnace volume and to enhance gaseous mixing for reduced CO emissions
while maintaining sufficiently high temperatures for fast oxidation. 相似文献
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Kyung-Suk Cho Hee Wook Ryu In Sook Lee Hyung-Min Choi 《Journal of the Air & Waste Management Association (1995)》2013,63(2):237-243
Abstract Microbial metal leaching from sewage sludge (2-9% w/v) was carried out with the iron-oxidizing bacterium Thiobacillus ferrooxidans. Measurements of pH, oxidation-reduction potential, and concentration of Fe2+ indicated that T. ferrooxidans was effective in removing metals from an incubation bath containing less than 5% sludge solids concentration. Specifically, Cu leaching was completely suppressed at a high solids concentration of 9% (w/v). Results indicated that the deactivation of T. ferrooxidans at a high sludge content was mainly due to the presence of inhibiting materials such as organic matter. A mixed culture of sulfur-oxidizing bacteria was obtained by enrichment from anaerobically digested sewage sludge to enhance the efficiency of the microbial leaching process. These bacteria were much more effective in metal leaching than was iron-oxidizing T. ferrooxidans. At 9% (w/v) solids concentration, the leaching efficiencies of Zn and Cu were 78% (2.66 g/kg dry sludge) and 59% (1.36 g/kg dry sludge), respectively. Therefore, when removing heavy metals from the anaerobically digested sewage sludge, the indigenous sulfur-oxidizing bacteria isolated in the current study were more efficient than T. ferrooxidans, especially at high sludge solids concentrations. 相似文献
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