Time filter

Source Type

Kwak Y.-H.,Kolon Engineering and Construction Co. | Lee Y.-M.,Hanyang University | Bae W.-K.,Hanyang University | Kim W.-H.,Korea Institute of Machinery and Materials | Bae S.-K.,Changwon National University
Journal of Material Cycles and Waste Management

This study was carried out to investigate the absorption reaction of chlorine and sulfur with Ca(OH)2 under simulated conditions related to the co-combustion of refuse-derived fuel and sewage sludge in the fluidized bed combustor, such as high temperature, moisture and a mixing of samples. The combustion experiments were carried out in an electrical furnace with PVC and sulfur powders as the waste samples. High-purity slaked lime powder was used to capture the chlorine and sulfur. The experimental results showed that the removal efficiencies of both chlorine and sulfur were over 90% when the mole ratios of Ca on Cl and S were over 2.5. Furthermore, simultaneous absorption was helpful in improving the removal efficiency of chlorine and sulfur. The presence of chlorine markedly increased the removal efficiency of sulfur. The removal efficiency of chlorine was the highest at 700°C in both independent and simultaneous absorption. The removal efficiency of sulfur increased as the temperature increased, but the removal efficiency of chlorine sharply decreased from 95 to 83% when the moisture content in gases increased from 0 to 20 vol%. These results were confirmed by the combustion test of granular CaCl2. © 2011 Springer. Source

Cho D.-W.,Korea Institute of Construction Technology | Kim K.,Kolon Engineering and Construction Co.
KSCE Journal of Civil Engineering

Moisture damage occurring within asphalt pavement causes the pavement to undergo several types of distress, such as stripping, potholes, and others. The durability or integrity related to moisture damage plays an important role in other types of damage or distress, such as rutting and fatigue. The development of a Dynamic Shear Rheometer (DSR) moisture damage test is the result of an effort to estimate the moisture damage in a simple, practical testing setup. As a conceptual supporting step, in turn, this paper provides fundamental, general mechanisms to explain the asphalt-aggregate bond behaviors during wet conditions in a DSR moisture damage test. Shear-thickening and thixotropy are introduced to explain the asphalt-aggregate interface behaviors under wet conditions, in view of a colloidal system. Moreover, the self-assembly concept is introduced with regard to a supramolecular system. Both systems can be associatively applicable because of their conceptual similarities. The analysis of data recorded during wet conditions supports and explains qualitatively the reversible structure of the asphalt-aggregate interface. © 2010 Korean Society of Civil Engineers and Springer-Verlag Berlin Heidelberg. Source

Ren X.,Beijing University of Civil Engineering and Architecture | Han H.J.,Seoul National University | Lee Y.J.,Seoul National University | Lee S.H.,Seoul National University | And 3 more authors.
Journal of Water and Health

Being a typical micropollutant, tris-(2-chloroethyl)-phosphate (TCEP) is often found in aquatic environments. However, the potential effects of TCEP at environmental concentrations on apoptotic mechanisms are mostly unknown. Thus, the purpose of this study is to investigate the apoptotic regulatory protein expression of TCEP at environmental concentration in primary cultured renal proximal tubule cells (PTCs). The results show that TCEP at 0.01 and 1 mg L -1 significantly increased the phosphorylation of c-Jun-NH2-terminal kinase (JNK) (135.5 and 138.0% of the control, respectively), and significantly decreased the expression of Bcl-2 and cIAP-2 at all tested concentrations, except for a slight decrease of Bcl-2 at 0.01 mg L-1. In addition, TCEP significantly increased the expression of caspase-3 at all three concentrations (132.6, 172.6 and 167.9% of the control, respectively) and caspase-9 at 1 and 10 mg L-1 (128.3 and 144.5% of the control, respectively). Furthermore, TCEP increased the apoptotic cell population in a flow cytometry analysis. In conclusion, environmental TCEP might have a dose-dependent proapoptotic effect with a decrease of DNA synthesis and cell number in primary cultured renal PTCs. © IWA Publishing 2012. Source

Chae K.-J.,Kolon Engineering and Construction Co. | Kim S.-M.,Kangwon National University | Oh S.-E.,Kangwon National University | Ren X.,Beijing University of Civil Engineering and Architecture | And 2 more authors.
Bioprocess and Biosystems Engineering

The spatial distribution and activities of nitrifying and denitrifying bacteria in sponge media were investigated using diverse tools, because understanding of in situ microbial condition of sponge phase is critical for the successful design and operation of sponge media process. The bacterial consortia within the media was composed of diverse groups including a 14.5% Nitrosomonas spp.-like ammonia oxidizing bacteria (AOB), 12.5% Nitrobacter spp.-like nitrite oxidizing bacteria (NOB), 2.0% anaerobic ammonium-oxidizing (ANAMMOX) bacteria and 71.0% other bacteria. The biofilm appeared to be most dense in the relatively outer region of the media and gradually decreased with depth, but bacterial viabilities showed space-independent feature. The fluorescent in situ hybridization results revealed that AOB and NOB co-existed in similar quantities on the side fragments of the media, which was reasonably supported by the microelectrode measurements showing the concomitant oxidation of NH4 + and production of NO3 - in this zone. However, a significantly higher fraction of AOB was observed in the center than side fragment. As with the overall biofilm density profile, the denitrifying bacteria were also more abundant on the side than in the center fragments. ANAMMOX bacteria detected throughout the entire depth offer another advantage for the removal of nitrogen by simultaneously converting NH 4 + and NO2 - to nitrogen gas. © 2012 Springer-Verlag. Source

Discover hidden collaborations