Gyeonggi Do, South Korea
Gyeonggi Do, South Korea

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Park H.C.,Yonsei University | Choi H.S.,Yonsei University | Kwak Y.-H.,Kolon Global Corporation
Journal of Material Cycles and Waste Management | Year: 2017

To investigate heat transfer of char from waste tire pyrolysis, the cooling of char was simulated by the computational fluid dynamics. To scrutinize the heat transfer characteristics, bed height, temperature of cooling wall, and mixing time were selected as calculation parameters. From the results, increasing the char bed height from 0.005 to 0.02 m, the total heat transfer is decreased as from 45.5 to 26.5 J. As the char bed height is further increased from 0.02 to 0.06 m, the total heat transfer is decreased from 26.5 to 9.1 J. The char bed height affects the total heat transfer significantly. The total heat transfer decreases from 15.9 to 14.0 J as the temperature of cooling wall increases from 273.15 to 323.15 K. The total heat transfer mildly depends on the temperature of cooling wall. The particle mixing time increases from 10 to 120 s and the total heat transfer decreases from 28.6 to 22.6 J. It is noted that the particle contact is enhanced between char particles as well as the particles and cooling wall as the particle mixing time decreases. Consequently, heat transfer is augmented. © 2017 Springer Japan

Hashimoto Y.,Mie University | Kang J.,North Carolina State University | Kang J.,Kolon Global Corporation | Matsuyama N.,Hirosaki University | Saigusa M.,Toyohashi University of Technology
Soil Science Society of America Journal | Year: 2012

Andisols derived from volcanic ash minerals are characterized by a high P retention capacity (PRC). The PRC of soil is often correlated with various soil properties, and a simple correlation analysis alone may not necessarily explain the direct cause and effect relationships between soil properties and PRC values. The objectives of this study were to determine which soil properties best explain the variability in the PRC of allophanic and non-allophanic Andisols using path analysis. A total of 671 Japanese Andisols were used in this study. The PRC values were determined for allophanic and non-allophanic soil samples, along with pH, organic matter (OM) contents, acid ammonium oxalate extractable Al (Al ox) and Fe (Fe ox), and pyrophosphate-extractable Al (Al p) and Fe (Fe p). The PRC value of allophanic soils was correlated with Al ox (r = 0.72) and Fe ox (r = 0.56). Path analysis revealed, however, that Al ox was the single most important direct effect on PRC, and the correlation between PRC and Fe ox was mostly partitioned to an indirect effect through Al ox. According to path analysis on non-allophanic soils, Al p was the single most important causal factor in predicting PRC, and the correlation between Al ox and PRC (r = 0.77) was mostly partitioned to an indirect effect through Al p. The correlation between OM and PRC was attributable to organically bound Al in allophanic soils by the indirect effect of Al p on PRC through OM. Pyrophosphate extraction may be a better indicator than oxalate extraction for predicting PRC in non-allophanic Andisols. © Soil Science Society of America.

Yoon J.-H.,Hanbat National University | Shim S.-R.,Hanbat National University | An Y.S.,Kolon Global Corporation | Lee K.H.,Hanbat National University
Energy and Buildings | Year: 2013

In this study, a mock-up facility equipped with both BIPV windows and normal clear windows was installed to carry out the actual measurement of long-term surface temperature characteristics as the preliminary step for analyzing the impact of the surface temperature rise of thin film BIPV modules on the PV performance. The measurement was carried out for clear double windows and BIPV double windows simultaneously for each inclined angle (0°, 30°, and 90°) for one year, and various statistical analyses were carried out for the collected annual surface temperature data to investigate the surface temperature characteristics of BIPV windows. The analysis result shows that the temperature of windows applied on the vertical plane rises significantly during the winter season, and the temperature of windows applied on the horizontal plane and the inclined plane rises significantly during the summer season with high solar altitude. Regarding indoor surface temperature of windows which is closely related with the thermal comfort of indoor occupants, the surface temperature of BIPV windows with low solar heat gain coefficient was 1 °C lower than that of normal windows during the day time in summer season and was approximately 2 °C higher during the night time in winter season due to the thermal insulation effect. © 2013 Elsevier B.V.

Chae K.-J.,Kolon Global Corporation | Kang J.,North Carolina State University
Energy Conversion and Management | Year: 2013

Increasing energy prices and concerns about global climate change highlight the need to improve energy independence in municipal wastewater treatment plants (WWTPs). This paper presents methodologies for estimating the energy independence of a municipal WWTP with a design capacity of 30,000 m 3/d incorporating various green energy resources into the existing facilities, including different types of 100 kW photovoltaics, 10 kW small hydropower, and an effluent heat recovery system with a 25 refrigeration ton heat pump. It also provides guidance for the selection of appropriate renewable technologies or their combinations for specific WWTP applications to reach energy self-sufficiency goals. The results showed that annual energy production equal to 107 tons of oil equivalent could be expected when the proposed green energy resources are implemented in the WWTP. The energy independence, which was defined as the percent ratio of green energy production to energy consumption, was estimated to be a maximum of 6.5% and to vary with on-site energy consumption in the WWTP. Implementing green energy resources tailored to specific site conditions is necessary to improve the energy independence in WWTPs. Most of the applied technologies were economically viable primarily because of the financial support under the mandatory renewable portfolio standard in Korea. © 2013 Published by Elsevier Ltd.

Kim K.-Y.,Gwangju Institute of Science and Technology | Chae K.-J.,Kolon Global Corporation | Choi M.-J.,Gwangju Institute of Science and Technology | Yang E.-T.,Gwangju Institute of Science and Technology | And 2 more authors.
Chemical Engineering Journal | Year: 2013

A new flow-through type microbial fuel cell (MFC) system was developed for practical application as a wastewater treatment process. The ultrafiltration MFC (UF-MFC), which has a UF membrane instead of an expensive cation exchange membrane (CEM) as a separator, was designed to continuously filter the anode chamber solution to cathode chamber via UF membrane. Through the UF-MFC system, high-quality effluent and electricity generation can be simultaneously achieved by the two different wastewater treatment processes applied, e.g., a biological organic pollutant removal in the anode chamber by electrochemically active bacteria and a physical filtration by UF membrane. The maximum power density of the UF-MFC was 53.5mW/m2, lower than the power density shown by comparison with a Nafion based two-chambered MFC (55.7mW/m2). However, the UF-MFC continuously produced high-quality effluent that did not need further post-treatment processes, showing a high and stable COD removal efficiency (>90%), and high rejection rate for total coliform (>97%) and suspended solids during 20d operation. This study confirmed that UF-MFC s could be a promising technology for both of efficient wastewater treatment and energy recovery from wastewater in future wastewater treatment plants. © 2012 Elsevier B.V.

Kim K.-Y.,Gwangju Institute of Science and Technology | Yang E.,Gwangju Institute of Science and Technology | Lee M.-Y.,Gwangju Institute of Science and Technology | Chae K.-J.,Kolon Global Corporation | And 2 more authors.
Water Research | Year: 2014

Membrane resistance is due to the low accessibility of liquid electrolytes onto the membrane surface; resultant membrane biofouling lowers the power generation capacity of microbial fuel cells (MFCs). In this study, in order to reduce membrane resistance caused by migrative ion transport resistance and membrane biofouling, a polydopamine (PD) coating was adopted for the modification of ultrafiltration (UF) membrane surfaces in UF membrane integrated MFCs (UF-MFCs). After a PD coating was applied to a UF membrane, the contact angle measured on the support layer of a UF membrane decreased and the membrane surface charge became negative. The maximum power density of UF-MFC increased after the PD coating on a UF membrane and a remarkable reduction of charge transfer resistance was observed using electrochemical impedance spectroscopy (EIS) analysis. Lower extracellular polymeric substance (EPS) concentrations and total cell numbers were observed on the PD coated UF membrane surface after 72h operation, although 17% of a permeate flux of UF-MFC decreased after PD coating. © 2014 Elsevier Ltd.

Chae K.-J.,Korea Maritime and Ocean University | Kim I.-S.,Korea Maritime and Ocean University | Ren X.,Beijing University of Civil Engineering and Architecture | Cheon K.-H.,Kolon Global Corporation
Energy Conversion and Management | Year: 2015

A micro-hydropower (MHP) system with a flow-variable turbine was tested for over one year to investigate its applicability for small-scale municipal wastewater treatment plants (WWTP) with severe flow fluctuations. The applied MHP was designed as a semi-Kaplan, equipped with only adjustable turbine blades without guide vanes, hence it is simple in its mechanical structure and is inexpensive while providing high-level performance. To exploit as much hydro-energy as possible, a maximum water level tracking control scheme in the forebay tank was employed and the turbine blade angle was accurately adjusted corresponding to the oncoming flow rate, which allows water to hit the blade in the best direction for maximum efficiency. Despite its micro-scale (12.3 kW at design conditions of 4.30 m net head and 0.35 m3/s flow rate), the applied MHP can work stably over a wide range of flows from 57% to 123% of the rated design flow, with the highest turbine efficiency of 91.3% and its corresponding overall electric efficiency of 80.3%. Even as the flow rate decreases to 23% of the design flow, the turbine still runs but at relatively lower efficiencies. Because of wide flow adjustability, the tested MHP can generate power even at extreme flow rates so that an almost complete amount (95.8%) of WWTP's total effluent was used to produce 68.1 MW h annually. In addition, as compared with similar WWTP-based hydropower systems in South Korea, the tested MHP achieved 1.78-2.80 times higher normalized electricity in both flow rate and net head, indicating a more efficient use of the flow and head. These results should draw new interest in the WWTP-based MHP, which was considered unfeasible in the past in Korea due to its low efficiency. © 2015 Elsevier Ltd. All rights reserved.

Lee K.-I.,Ajou University | Yeom D.,Ajou University | Kim E.-J.,Kolon Global Corporation
Journal of Asian Architecture and Building Engineering | Year: 2013

As quality of life has become a center of attention internationally, studies on comfortable indoor environments have been actively conducted. Particularly, the number of patients suffering from indoor air quality related diseases such as atopic dermatitis and new house syndrome have increased and the average time spent indoors these days is more than half a day, so counter solutions have been attempted in the field of architecture, such as using eco-friendly and ecological materials. With this background, this research aimed to verify the effect of rice hull insulation on the indoor environment, which is widely used in rural areas. To do this, two real-scale mock-ups with rice hull insulation and polystyrene insulated panels, which is the construction generally used in rural areas, were constructed and analyzed, and the effect of rice hull insulation on an indoor environment was verified.

Tran N.T.,Sejong University | Tran T.K.,Ho Chi Minh City University of Technology and Education | Jeon J.K.,Kolon Global Corporation | Park J.K.,Sejong University | Kim D.J.,Sejong University
Cement and Concrete Research | Year: 2016

The fracture energy of ultra-high-performance fiber-reinforced concrete (UHPFRC) at high strain rates (5-92 s-1) was investigated, and specimens with 1-1.5% fibers exhibited very high fracture energy (28-71 kJ/m2). Evaluation of the rate effects on the UHPFRC fracture resistance, including fracture strength (ft), specific work-of-fracture (WS), and softening fracture energy (WF), indicated that ft and WS were highly sensitive to strain rate, whereas WF was not. The effects of fiber type, volume content, specimen shape and fiber blending on the fracture resistance at high and static strain rates differed significantly: 1) smooth fibers exhibited higher ft and WS at high rates than twisted fibers; 2) higher fiber volume content did not clearly generate higher WS and WF at high rates; 3) notched specimens generally exhibited higher fracture resistance than un-notched samples at both static and high rates; and 4) UHPFRC blending two fibers produced higher WS and WF than UHPFRC with mono fiber at high rates. © 2015 Elsevier Ltd.

The present invention provides a seawater resistant grout material composition and a method for constructing an offshore wind turbine structure using the same, the seawater resistant grout material composition comprising: 210 wt % of high strength admixture; 2535 wt % of type I Portland cement; 3045 wt % of silica sand having a particle size of 3060 mesh; 515 wt % of silica sand having a particle size of 60100 mesh; and 510 wt % of silica sand having a particle size of 100200 mesh, wherein the high strength admixture is obtained by mixing and pulverizing 4599 wt % of slag and 155 wt % of anhydrite, thus the present invention has excellent seawater resistance, excellent strength development characteristics at a low temperature, and increased compressive strength and durability to allow withstanding cyclic loads due to wind and wave pressure.

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