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991.
Myong Hwan Sohn Kyung Won Seo Yong Seok Choi Sang Joon Lee Young Sil Kang Yang Soon Kang 《Marine Biology》2011,158(3):561-570
The marine dinoflagellate Cochlodinium polykrikoides is a harmful and highly motile algal species. To distinguish between the motility characteristics of solitary and chain-forming
cells, the swimming trajectories and speeds of solitary cells and 2- to 8-cell chains of C. polykrikoides were measured using a digital holographic particle tracking velocimetry (PTV) technique. C. polykrikoides cells exhibited helical swimming trajectories similar to other dinoflagellate species. The swimming speed increased as the
number of cells in the chain increased, from an average of 391 μm s−1 (solitary cells) to 856 μm s−1 (8-cell chain). The helix radius R and pitch P also increased as the number of cells in the chain increased. R increased from 9.24 μm (solitary cell) to 20.3 μm (8-cell chain) and P increased from 107 μm (solitary cell) to 164 μm (8-cell chain). The free thrust-generating motion of the transverse flagella
and large drag reduction in the chain-forming cells seemed to increase the swimming speed compared to solitary cells. The
measured swimming speeds agreed with those from field observations. The superior motility of chain-forming C. polykrikoides cells may be an important factor for its bloom, in addition to the factors reported previously. 相似文献
992.
Structural investigation of catalyst deactivation of Pt/SDB for catalytic oxidation of VOC-containing wastewater 总被引:2,自引:0,他引:2
The stability of styrene-divinyl benzene copolymer (SDB)-supported Pt (Pt/SDB) catalysts for destruction of volatile-organic-compound (VOC) in wastewater was examined. The test reaction was wet oxidation of water-containing aliphatic alcohol and formaldehyde at 140 degrees C and 90 psig for 40 h. The catalytic performance tests indicated that activity of the Pt/SDB catalysts could be maintained for VOC concentration of 3 wt.%, whereas the catalysts deactivated rapidly for 10 wt.% VOC containing wastewater. In order to investigate the nature of catalyst deactivation, extended X-ray absorption fine structure (EXAFS) and X-ray absorption near edge (XANES) spectroscopy were used to characterize the fresh and used catalysts. After the reaction, there is no oxidation of Pt clusters observed in EXAFS and XANES spectroscopy suggesting that the oxidation reaction takes places via the adsorbed oxygen. The spectroscopy results further indicated that deactivation of the catalysts were mainly caused by the increase of Pd particle size. After the reaction, the Pt-Pt coordination number has no significant change for the 3 wt.% wastewater whereas increase from 5.6 to 6.2 for 10 wt.% wastewater. Combined with the fact that the catalysts fractured during the reactions, we suggested that Pt agglomeration was mainly caused by thermal migration of the metal clusters. 相似文献
993.
Airborne particulate matter (PM) concentrations were measured in Iksan, a suburban area in South Korea during April, 2003.
PM2.5 (particles with an aerodynamic diameter less than 2.5 μm) and PM10 (particles with an aerodynamic diameter less than 10 μm) samples were collected, and the chemical characteristics of particles
were examined for diurnal patterns, yellow dust/rainfall influences, and scavenging effects. Average concentrations of PM2.5 and PM10 mass measured were 37.3 ± 16.2 μg m−3 and 60.8 ± 29.5 μg m−3, respectively. The sum of ionic chemical species concentrations for PM2.5 and PM10 was 16.9 ± 7.3 and 23.1 ± 10.1 μg/m3, respectively. A significant reduction in PM mass concentrations during rainfall days was observed for coarse mode (PM2.5 − 10) particles, but less reduction was found for fine (PM2.5) mass concentration. SO4
2−, NH4
+, and K+ predominated in fine particulate mode, NO3
− and Cl− predominated in fine particle mode and coarse particle mode, but Na+, Mg2+, and Ca2+ mostly existed in coarse mode. The high concentration of ammonium due to local emissions and long-range transport neutralized
sulfate and nitrate to ammonium sulfate and ammonium nitrate, which were major forms of airborne PM in Iksan. Average mass
concentrations of PM10 in daytime and at night were 57.6 and 70.0 μg m−3, and those of PM2.5 were 35.4 and 42.5 μg m−3, respectively. NO3
− and Cl− in both PM2.5 and PM10 were about double at night than in the daytime, while the rest of the chemical species were equal or a little higher at night
than in the daytime. The results suggest the formation of ammonium nitrate and chloride when high ammonia concentration and
low air temperature are allowed. Backward air trajectory analyses showed that air masses arriving at the site during yellow
dust period were transported from arid Chinese regions, which resulted in high concentrations of airborne PM mass concentrations.
In the meantime, air mass trajectories during a rainfall period were mostly from the Pacific Ocean or the East China Sea,
along with a relatively low PM concentration. 相似文献
994.
Waste incineration in a small incinerator is a simple and convenient way of treating waste discharged from small areas or from large facilities and buildings such as business centers, marketplaces, factories, and military units. Despite their ostensible advantages, however, many small incinerators frequently suffer from serious problems, e.g., unsystematic waste feeding, unstable combustion, deficient air pollution control devices, and consequently, environmental pollution. To obtain a better understanding of the characterization of wastes in small incinerators, we investigated a series of fundamental characteristics, i.e., physical composition, bulk density, proximate and ultimate analysis, potential energy content, and so on. The main waste components in small incinerators were identified as paper and plastic; the proportion of food waste was less than that in large incinerators. Especially, a low ratio of food waste had a strong influence on other waste characteristics, e.g., lower moisture content and bulk density, and higher potential energy. On the other hand, in contrast with that of HCl, there was no distinguishable linear relationship between Cl content in waste and PCDD/DF concentration in combustion gas. 相似文献
995.
Tara Sankar Pathak Jin San Kim Se-Jong Lee Dae-Jin Baek Ki-Jung Paeng 《Journal of Polymers and the Environment》2008,16(3):198-204
Alginic acid and metal alginates are prepared from fresh algae using extraction method. A FTIR spectrum indicates that alginic
acid is converted into the metal alginate. Comparing calcium and cobalt alginates, asymmetric stretching of free carboxyl
group of calcium alginate at 1630 cm−1 is shifted to 1585 cm−1 in cobalt alginate, due to the change of charge density, radius and atomic weight of the cation, creating a new environment
around the carbonyl group. The strong exothermic peak of alginic acid in DSC thermogram indicates the decomposition of biopolymer,
whereas strong exothermic peak of metal alginate in DSC thermogram attributed to the decomposition of biopolymer and formation
of respective carbonate. Based on DSC study, the decomposition of cobalt alginate occurs at higher temperature comparing to
those of sodium and calcium alginate, which may conclude into the higher stability of cobalt alginate. TGA results reveal
that, cobalt alginate is more stable than calcium and sodium alginate at 300 °C temperature. Surface morphology (at same magnification),
as well as porosity (%) and pore size distribution results change with metals present in different metal alginates. 相似文献
996.
Jha MK Choubey PK Jha AK Kumari A Lee JC Kumar V Jeong J 《Waste management (New York, N.Y.)》2012,32(10):1919-1925
Printed circuit boards (PCBs) are the most essential components of all electrical and electronic equipments, which contain noteworthy quantity of metals, some of which are toxic to life and all of which are valuable resources. Therefore, recycling of PCBs is necessary for the safe disposal/utilization of these metals. Present paper is a part of developing Indo-Korean recycling technique consists of organic swelling pre-treatment technique for the liberation of thin layer of metallic sheet and the treatment of epoxy resin to remove/recover toxic soldering material. To optimize the parameters required for recovery of tin from waste PCBs, initially the bench scale studies were carried out using fresh solder (containing 52.6% Sn and 47.3% Pb) varying the acid concentration, temperature, mixing time and pulp density. The experimental data indicate that 95.79% of tin was leached out from solder material using 5.5M HCl at fixed pulp density 50g/L and temperature 90°C in mixing time 165min. Kinetic studies followed the chemical reaction controlled dense constant size cylindrical particles with activation energy of 117.68kJ/mol. However, 97.79% of tin was found to be leached out from solder materials of liberated swelled epoxy resin using 4.5M HCl at 90°C, mixing time 60min and pulp density 50g/L. From the leach liquor of solder materials of epoxy resin, the precipitate of sodium stannate as value added product was obtained at pH 1.9. The Pb from the leach residue was removed by using 0.1M nitric acid at 90°C in mixing time 45min and pulp density 10g/L. The metal free epoxy resin could be disposed-of safely/used as filling material without affecting the environment. 相似文献
997.
Yus Donald Chaniago Jae-Kyeong Kim Myung-Jun Park Kee-Kahb Koo Moonyong Lee 《Journal of Material Cycles and Waste Management》2016,18(2):366-376
Currently, waste photoresist stripper from the semiconductor industries is generally incinerated at high temperatures or processed as a high-calorie fuel, which can have adverse effects on the environment and economy. Recovery of valuable solvents from waste photoresist strippers is, therefore, very important for thin flat transistor-liquid crystal display (TFT-LCD) manufactures to reduce the production costs and protect the environment against industrial waste. In the present work, systematic laboratory-scale distillation experiments were carried out to regenerate the organic solvents from the waste photoresist stripper and determine if they are feasible to recycle for commercial TFT-LCD grade chemicals: in particular, 1-hydroxyethylpiperazine and methyl diglycol were mainly tried to retrieve. Based on the experiment results, possible alternative distillation sequences were examined through intensive techno-economic analysis using a rigorous process simulator. As a result, an optimal distillation sequence and condition were drawn to separate valuable organic solvents from waste photoresist stripper for a commercial purpose recovery process. 相似文献
998.
A New Perspective on Sustainable Soil Remediation—Case Study Suggests Novel Fungal Genera Could Facilitate in situ Biodegradation of Hazardous Contaminants 下载免费PDF全文
Lauren M. Czaplicki Ellen Cooper P. Lee Ferguson Heather M. Stapleton Rytas Vilgalys Claudia K. Gunsch 《补救:环境净化治理成本、技术与工艺杂志》2016,26(2):59-72
Deciding upon a cost effective and sustainable method to address soil pollution is a challenge for many remedial project managers. High pressure to quickly achieve cleanup goals pushes for energy‐intensive remedies that rapidly address the contaminants of concern with established technologies, often leaving little room for research and development especially for slower treatment technologies, such as bioremediation, for the more heavily polluted sites. In this case study, new genomic approaches have been leveraged to assess fungal biostimulation potential in soils polluted with particularly persistent hydrophobic contaminants. This new approach provides insights into the genetic functions available at a given site in a way never before possible. In particular, this article presents a case study where next‐generation sequencing has been used to categorize fungi in soils from the Atlantic Wood Industries Superfund site in Portsmouth, Virginia. Data suggest that original attempts to harness fungi for bioremediation may have focused on fungal genera poorly suited to survive under heavily polluted site conditions, and that more targeted approaches relying on native indigenous fungi which are better equipped to survive under site‐specific conditions may be more appropriate. ©2016 Wiley Periodicals, Inc. 相似文献
999.
Jeong-Hun Kim Yong-Chil Seo Deepak Pudasainee Sang-Hyeob Lee Sung-Jin Cho Ha-Na Jang Ju-Myon Park Geum-Ju Song Kyu-Shik Park 《Journal of Material Cycles and Waste Management》2009,11(3):183-190
The development of regulations patterned after the United States’ requirement for maximum achievable control technology (MACT)
to control hazardous air pollutants from major industrial sources in Korea is in progress. Current management practices and
installed air pollution control devices were surveyed; emission tests and continuous emission data collected from facilities
under operation were assessed considering other MACT requirements such as reporting, report keeping requirements. Emission
sampling and air pollutant analysis were carried out at representative hazardous waste incinerators installed with wet-type
and dry-type air pollution control devices. Korean and United States Environmental Protection Agency methods were used for
sampling and analysis. The major heavy metals emitted were Zn, Ni, Pb, and Cr. The heavy metal removal efficiency of existing
air pollution control devices was greater than 99%. The average mercury removal efficiency was more than 30%. Toluene; m,p-xylene; o-xylene; benzene; dichloromethane; styrene; ethylbenzene; 1,3-dichlorobenzene; and 1,2,4-trimethylbenzene were the major volatile
organic compounds emitted. The emissions from field tests were compared, reviewed, and analyzed with respect to MACT regulations
to check applicability. Finally, draft guidelines were suggested for effective hazardous air pollutant management in Korea. 相似文献
1000.
Seungmoon Lee Seung-Kwun Yoo Jaehoon Lee Jin-Won Park 《Journal of Material Cycles and Waste Management》2009,11(3):191-196
In this study, experimental conditions were optimized to maximize the production of hydrogen gas from refuse plastic fuel
(RPF) by pyrolysis and steam gasification processes conducted in a laboratory-scale reactor. We carried out gasification using
10-g RPF samples at different temperatures (700°-1000°C) with and without steam. The effect of the amount of steam (0–0.25
g/min) for RPF steam gasification was also studied. The effect of K2CO3 as a catalyst on these processes was also investigated. Experimental results showed that the hydrogen gas yield increased
with temperature; with respect to the gas composition, the hydrogen content increased mainly at the expense of other gaseous
compounds, which highlights the major extension of secondary cracking reactions in the gaseous fraction at higher temperatures. 相似文献