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331.
PCDD/F and dioxin-like PCB in Hong Kong air in relation to their regional transport in the Pearl River Delta region 总被引:3,自引:0,他引:3
PCDD/F and dioxin-like PCB were measured in 142 air samples of Hong Kong. The annual average PCDD/F and dioxin-like PCB concentrations obtained for Hong Kong air at Tap Mun (PCDD/F: 1724+/-1984; dioxin-like PCB: 1572+/-1170 fg m(-3)), Yuen Long (PCDD/F: 2927+/-2695; dioxin-like PCB: 4331+/-1962 fg m(-3)) and Tsuen Wan (PCDD/F: 1875+/-1502; dioxin-like PCB: 2972+/-1510 fg m(-3)) from January 2004 to March 2005 were comparable to other urban centers around the world and were within the Japanese and USA ambient air quality guidelines. A clear seasonal pattern was observed for PCDD/F, generally with a 50-60 times higher air concentration in winter when background northerly wind was weaker and land-sea breeze prevailed, resulting in regional transport; and a lower concentration in summer, due to the inflow of clean oceanic southeasterly wind from the South China Sea. A higher WHO-TEQ value of dioxin-like PCB (mainly attributed to the relatively higher WHO-TEQ value of PCB 126) in Yuen Long during winter, compared with other months, could also be related to the regional transport by the winter monsoon wind and the low mixing height in winter. Spatially, air concentrations of PCDD/F and dioxin-like PCB demonstrated a west-to-east gradient (with Yuen Long>Tsuen Wan>Tap Mun). It is suggested that PCDD/F and dioxin-like PCB were transported into the western airshed of Hong Kong from the Pearl River Delta by land-sea breeze circulation and confined to the northwestern part, due to the blocking effect of the northwestern airshed in Hong Kong. 相似文献
332.
This study expands the negotiation literature by examining how negotiator behavior is predicted by various emotions felt by the negotiators and their counterparts and by counterpart negotiation behavior. Using hierarchical linear modeling, we also compare individual‐ and dyad‐level processes that lead to negotiator behavior and outcomes. The results from a dyadic negotiation simulation showed that both the valence and agency of negotiator and counterpart emotions need to be considered to understand the roles of emotion in negotiator behavior. Negotiators tend to reciprocate counterparts' integrating, compromising, and dominating behaviors, but they also offer complementary (or matching) responses to the counterparts' dominating and yielding behaviors. Integrating behavior was more dependent on dyad‐level interpersonal dynamics than were the other behaviors. The comparison of negotiator‐level and dyad‐level results suggests that negotiation needs to be understood in the context of collective exchanges as well as individual‐level cognitive processes. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
333.
Developing Peak Discharges for Future Flood Risk Studies Using IPCC's CMIP5 Climate Model Results and USGS WREG Program 下载免费PDF全文
Sivasankkar Selvanathan Mathini Sreetharan Krista Rand Dmitry Smirnov Janghwoan Choi Mathew Mampara 《Journal of the American Water Resources Association》2016,52(4):979-992
Extreme climate events, floods, and drought, cause huge impact on daily lives. In order to produce society resilient to extreme events, it is necessary to assess the impact of frequent and high intensity storm events on design parameters. This article describes a methodology to develop future peak “design discharges” throughout the United States that can be used as a guidance to map future floodplains. In order to develop a lower and upper limit for anticipated peak flow discharges, two future growth scenarios — Representative Concentration Pathways (RCPs)‐RCP 2.6 and 8.5 were identified as the weak and strong climate scenario respectively based on the output from the global climate models. The Generalized Least Square technique in United States Geological Survey's Weighted Multiple Regression (WREG) program was used to develop regression equations that relate peak discharges to basin and climate parameters of the contributing watershed. The design discharges reflect the most recent climate model results. Number of frost days, heavy rainfall days, high temperature days, and snow depth were found to be the common extreme climate parameters influencing the regression equations. This methodology can be extended to other flood frequency events if rainfall data is available. The future discharges can be utilized in hydraulics models to estimate floodplains that can assist in resilient infrastructure planning and outline climate change adaptation strategies. 相似文献
334.
Seok-Beom Roh Sung-Kwun Oh Eun-Kyu Park Woo Zin Choi 《Journal of Material Cycles and Waste Management》2017,19(3):1093-1105
To accomplish the effective classifier and secure the accurate classification capabilities of black plastics, a comprehensive design methodology of fuzzy radial basis function neural networks is developed with the aid of principal component analysis and particle swarm optimization. Plastics recycling is the competitive method which can deal with the shortage of natural resource. To recycle and reuse the waste plastics, this study is given as the key issue to identify and classify waste plastics by resin type such as polyethylene terephthalate, polypropylene, polystyrene, etc. To complement the weak points of recognition and classification of the near-infrared radiation equipment, Raman spectroscopy is used to obtain qualitative as well as quantitative analysis of black plastics. To improve the identification performance of black plastics, an intelligent computing algorithm such as fuzzy radial basis function neural networks classifier and preprocessing algorithm as principal component analysis are applied to analyze and classify the obtained spectrum of black plastics. Finally, to optimize the structure as well as parameters of fuzzy radial basis function neural networks, particle swarm optimization technique is used. The obtained experimental results show that the proposed network architecture exhibits high classification capabilities in practical applications. 相似文献
335.
Kim KH Baek SO Choi YJ Sunwoo Y Jeon EC Hong JH 《Environmental monitoring and assessment》2006,118(1-3):407-422
In this study, concentrations of major aromatic VOCs were determined from landfill gas (LFG) at a total of five municipal
landfill sites in Korea including Nan Ji (NJ), Woon Jung (WJ), Sam Poong (SP), Hoei Chun (HC), and No Hyung (NH). The concentration
levels of those VOC were found to be significantly different, mainly as a function of such a parameter as landfill aging.
The VOC concentrations measured from the unclosed landfill sites (e.g., WJ) were characterized by exceedingly high values
above a few tens of ppm. However, the results of the abandoned site (e.g., SP) were about three orders of magnitude lower
than the others so as to merely exceed the typical ambient concentration levels. It was most striking to find a systematic
dominance of toluene over other aromatic VOC under most circumstances. The LFG flux values of all aromatic VOC and the four
specific major ones (termed as BTEX: benzene, toluene, ethylbenzene, and xylene) were also computed for each vent pipe from
all study sites using their concentrations and the concurrently determined environmental parameters. The results, if calculated
in terms of the average BTEX quantity emitted per vent pipe, showed that the magnitude of their emissions can vary substantially,
with the values ranging from 0.05 (SP) to 49.2 kg yr−1 (WJ in wintertime). The LFG flux values of aromatic VOC, when compared to the contribution of non-methane hydrocarbons (NMHC),
were able to explain a constant, but minor, proportion of the LFG carbon budget. 相似文献
336.
The Characteristics of Tropospheric Ozone Seasonality Observed from Ozone Soundings at Pohang, Korea
This paper presents the first analysis of vertical ozone sounding measurements over Pohang, Korea. The main focus is to analyze
the seasonal variation of vertical ozone profiles and determine the mechanisms controlling ozone seasonality. The maxima ozone
at the surface and in the free troposphere are observed in May and June, respectively. In comparison with the ozone seasonality
at Oki (near sea level) and Happo (altitude of 1840 m) in Japan, which are located at the same latitude as of Pohang, we have
found that the time of the ozone maximum at the Japanese sites is always a month earlier than at Pohang. Analysis of the wind
flow at the surface shows that the wind shifts from westerly to southerly in May over Japan, but in June over Pohang. However,
this wind shift above boundary layer occurs a month later. This wind shift results in significantly smaller amounts of ozone
because the southerly wind brings clean wet tropical air. It has been suggested that the spring ozone maximum in the lower
troposphere is due to polluted air transported from China. However, an enhanced ozone amount over the free troposphere in
June appears to have a different origin. A tongue-like structure in the time-height cross-section of ozone concentrations,
which starts from the stratosphere and extends to the middle troposphere, suggests that the ozone enhancement occurs due to
a gradual migration of ozone from the stratosphere. The high frequency of dry air with elevated ozone concentrations in the
upper troposphere in June suggests that the air is transported from the stratosphere. HYSPLIT trajectory analysis supports
the hypothesis that enhanced ozone in the free troposphere is not likely due to transport from sources of anthropogenic activity. 相似文献
337.
Kim KH Choi YJ Oh SI Sa JH Jeon EC Koo YS 《Environmental monitoring and assessment》2006,121(1-3):341-352
In order to explore the environmental behavior of reduced sulfur compounds (RSC) as malodorous components emitted from diverse source processes, the distribution characteristics of four sulfur (S) compounds - hydrogen sulfide (H2S), methyl mercaptan (CH3SH), dimethyl sulfide (DMS: (CH3)2S), and dimethyl disulfide (DMDS: (CH3)2S2) – were investigated in a municipal landfill area. In the course of this study, their ambient concentration levels were measured during two time periods from 13 individual spots selected as a function of distance from the center of the landfill site. The results generally indicated the absolute dominance of H2S over the other S compounds investigated (up to 5 km radius) such that their mean values were found as 1415 (H2S), 148 (DMS), 20.6 (CH3SH), and 14.4 ppt (DMDS). When our data were compared in terms of either varying distance from the source or relationship with meteorological conditions, the H2S data sets were most evident to reflect the potential effects of strong source processes in the landfill environment, relative to other S gases (or to volatile organic compounds measured concurrently). The results of this study further indicated the relatively good correspondence between the measured H2S concentration level and humans' intuitive sensory of odor and nuisance. 相似文献
338.
Ji Eun Lee Hang Seok Choi Yong Chil Seo 《Journal of Material Cycles and Waste Management》2014,16(4):665-676
For designing an efficient circulating fluidized bed reactor, understanding the complex hydrodynamic characteristics in the reactor is required. Hence, in the present study, the modeling and simulation of the circulating fluidized bed gasifier using plastic waste were carried out with Eulerian-Granular approach. Several cases were investigated as changing superficial gas velocities or sizes of plastic waste particle. Firstly, cases were examined with four different velocities when the particle diameter is 1 mm. At the gas velocity of 6 or 8 m/s, gas volume fraction is more than 95 % throughout the reactor and particle velocity has positive value overall. Therefore, a circulating fluidized bed seems to be formed in both cases. Comparing those two cases, better solid mixing can be expected considering the mass fraction and solid velocity at the superficial gas velocity of 6 m/s. Thus this case was further studied for the effect of particle size. As the diameters of plastic waste particle are 1 or 3 mm, it is considered that a circulating fluidized bed is formed. And plastic waste and sand particles are well mixed throughout the reactor. However, the particle diameter increases over 3 mm then, it is very hard to maintain circulating fluidization condition. 相似文献
339.
Muhammad Kashif Shahid Yunjung Kim Young-Gyun Choi 《Frontiers of Environmental Science & Engineering》2019,13(5):71
340.
Heavy metal immobilization in soil near abandoned mines using eggshell waste and rapeseed residue 总被引:3,自引:0,他引:3
Sang Soo Lee Jung Eun Lim Samy A. M. Abd El-Azeem Bongsu Choi Sang-Eun Oh Deok Hyun Moon Yong Sik Ok 《Environmental science and pollution research international》2013,20(3):1719-1726
Heavy metal contamination of agricultural soils has received great concern due to potential risk to human health. Cadmium and Pb are largely released from abandoned or closed mines in Korea, resulting in soil contamination. The objective of this study was to evaluate the effects of eggshell waste in combination with the conventional nitrogen, phosphorous, and potassium fertilizer (also known as NPK fertilizer) or the rapeseed residue on immobilization of Cd and Pb in the rice paddy soil. Cadmium and Pb extractabilities were tested using two methods of (1) the toxicity characteristics leaching procedure (TCLP) and (2) the 0.1 M HCl extraction. With 5 % eggshell addition, the values of soil pH were increased from 6.33 and 6.51 to 8.15 and 8.04 in combination with NPK fertilizer and rapeseed residue, respectively, compared to no eggshell addition. The increase in soil pH may contribute to heavy metal immobilization by altering heavy metals into more stable in soils. Concentrations of TCLP-extracted Cd and Pb were reduced by up to 67.9 and 93.2 % by addition of 5 % eggshell compared to control. For 0.1 M HCl extraction method, the concentration of 0.1 M HCl-Cd in soils treated with NPK fertilizer and rapeseed residue was significantly reduced by up to 34.01 and 46.1 %, respectively, with 5 % eggshell addition compared to control. A decrease in acid phosphatase activity and an increase in alkaline phosphatase activity at high soil pH were also observed. Combined application of eggshell waste and rapeseed residue can be cost-effective and beneficial way to remediate the soil contaminated with heavy metals. 相似文献