• Journal of the Korean Recycled Construction Resources Institute
• /
• v.7 no.1
• /
• pp.76-83
• /
• 2012

In this study, the research examined the effect on FC, WG, RP replacement ratio on the quality improvement of BS mortar using the RA. First of all, the flow value increased as the FC contents increased, and decreased as the WG and RP contents increased. The air contents was reduced as the FC and RP contents increased, but was increased as the WG contents went up While the compressive strength of 1 : 7 mix proportion increased with the increase of the FC and WG contents, it decreased as there was more RP contents. The compressive strength of RP could increase as the mix proportion increased, but the difference depending on the improvement material type and replacement ratio decreased gradually. The absorption deteriorated as the FC and RP contents increased in all the mix proportions, but improved a little when WG was used. Meanwhile, the absorption decreased as the compressive strength improved in all the mix proportions as a correlation, but the order was FC, RP and WG depending on the quality improvement material types. The FC and WG were most favorable in terms of quality improvement as a total analysis, and the RP and WG was most effective in terms of economical efficiency and resource recycling.

• Korean Journal of Organic Agriculture
• /
• v.20 no.4
• /
• pp.669-685
• /
• 2012

This study was carried out to investigate the nutrient value and yield response of corn, barley, and sudangrass by the application of anaerobic liquid fertilizer in two tidal land soil in order to design the resource recycling agricultural system between livestock and forage crop cultivation in a environment friendly agricultural region. Forage crop yields at reclaimed tidal soil during were at the level of 64~76% comparing with forage crop yields at upland soil in the cropping system of corn, barley, and sudangrass. And yields of forage crops were in the order of barley > corn > sudangrass in the cultivated cropping system for 2 year. Relative feed values (RFVs) of forage crops were 88%~106% for corn, 90%~111% for barley, and 91%~113% for sudangrass, and the carrying capacity of beef cattle (Hanwoo) was 5.8~8.6 head/year/ha for the corn-barley cropping system of one year, and 4.8~6.7 head/year/ha for the barley-sudangrass cropping system of one year. Also, carrying capacity of beef cattle (Hanwoo) was highest in the application level of anaerobic liquid fertilizer 200%.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.18 no.3
• /
• pp.133-142
• /
• 2014

Recently, more focus is shift to imbalances in aggregate market supply and demand and an exhaustion of natural resources. In this situation, Electric arc furnace oxidizing slag (EAF Slag) has high application possibility as aggregate for concrete due to similar property with general aggregate. In this study, We've got the plan to assure the chemical stability of EAF Slag, and then experimentally tested the mechanical performance and durability for the fine aggregate used EAF Slag. On this test result, we suggest the application plan. At the result of this study, it shows that EAF slag would reduce the surface defect such as pop-out due to natural aging for the fixed hour and adjustment the grain size of EAF Slag. And mechanical performance and durability according to the replacement rate of concrete service, were revealed more than equal or equal compare to general aggregate. Hereafter, quality control must precede not to impede the beauty of concrete surface as assure the safety for aging and processing. And, to establish the environmental resource recycling system for by-products of steel, it should be made development of various application and guideline of quality control for the EAF slag aggregate. Moreover, it must be constantly studied all kind of engineering performance and durability for related to this study.

• Journal of Korean Society of Environmental Engineers
• /
• v.32 no.9
• /
• pp.870-878
• /
• 2010

We investigated the concentration and the sources of ubiquitous persistent organic pollutants [i.e., 17 toxic polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), 12 coplanar polychlorinated biphenyls (Co-PCBs), and 16 priority polycyclic aromatic hydrocarbons (PAHs)] in waste papers and lumbers from industrial complexes. The total concentrations in waste papers and lumbers ranged from 9.69~176.77 pg/g-dry and 0.14~0.25 pg/g-dry for 17 PCDD/Fs, 109.95~4097.25 pg/g-dry and 28.23~59.88 pg/g-dry for 12 Co-PCBs and 9.30~52.18 ng/g-dry and 0.82~1.82 ng/g-dry for 16 PAHs respectively. Generally, the concentration of these pollutants in waste papers was higher than those in waste lumbers. OCDD was dominant in waste papers and lumbers and the PCDD/F patterns of these samples were similar with that of stack gas. The distribution patterns of Co-PCBs in wastes were related with commercial PCB products, indicating the effect of commercial PCB products on ubiquitous environment. The diagnostic ratios of several PAH compounds in waste paper showed that they were related with pyrogenic sources.

• The Korean Journal of Community Living Science
• /
• v.28 no.4
• /
• pp.613-623
• /
• 2017

This study was conducted to investigate the set up and running status of school gardening at elementary schools in Jeollabuk-do. Among 416 elementary schools in Jeollabuk-do, 164 schools (39.4%) had school gardens. Ninety-seven schools in cities and 67 in counties had school gardens. The total area and school garden size at schools in Jeollabuk-do were $45,490m^2$ and $277m^2$ per school, respectively, as well as $1.6m^2$ per students. School gardens varied in type, and percentages of outdoor and off-campus gardens were 67.2% and 17.2%, respectively. There were differences in the set up, type of garden, annual operating budget, and participants in school garden programs according to the location (city or county) of the school The installation and automation of facilities in the garden (such as greenhouse, tool shed, resource recycling facility, etc.) were poor. Most schools grew various kinds of plants, including vegetables, crops, ornamentals, and fruits. Teachers most often operated school gardens and taught students. Teachers had difficulty managing school gardens due to absence of knowledge about sustaining gardens. Most respondents reported the need for a school garden training program. Sixty-one percent of schools reported that the garden was used for academic instruction, especially during class. The majority of respondents agreed that school gardens have a positive effect and wanted to increase classes related to school gardens. Accordingly, in order to sustain school gardens and maximize their effects, systematic and customized support is needed that considers the characteristics and circumstances of the school. The facilities and features of the garden should be improved, and the school garden training program for teachers should attempt to reduce the effort required to manage the garden and increase utilization efficiency. In addition, participation of garden coordinators, parents, and community volunteers in managing gardens and implementing garden lessons is required.

• Journal of Adhesion and Interface
• /
• v.22 no.1
• /
• pp.1-7
• /
• 2021

The importance of high capacity energy storage devices has recently emerged for stable power supply through renewable energy generation. From this point of view, the Na-air battery (NAB), which is a next-generation secondary battery, is receiving huge attention because it can realize a high capacity through abundant and inexpensive raw materials. In this study, activated carbon-based catalysts for hybrid type Na-air batteries were prepared and their characteristics were compared and analysed. In particular, from the viewpoint of resource recycling, activated carbon (Orange-C) was prepared using discarded orange peel, and performance was compared with Vulcan carbon, which is widely used. In addition, a Pt/C catalyst (homemade-Pt/C, HM-Pt/C) was synthesized using a modified polyol method to check whether the prepared activated carbon can be used as a supported catalyst, and a commercial Pt/C catalyst (Commercial Pt/C) and electrochemical performance were compared. The prepared Orange-C exhibited a typical H3 type BET isotherm, which is evidence that micropore and mesopore exist. In addition, in the case of HM-Pt/C, it was confirmed through TEM analysis that Pt particles were evenly distributed on the activated carbon supported catalyst. In particular, the HM-Pt/C-based NAB showed the smallest voltage gap (0.224V) and good voltage efficiency (92.34%) in the 1st galvanostatic charge-discharge test. In addition, the cycle performance test conducted for 20 cycles showed the most stable performance.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.7 no.2
• /
• pp.116-122
• /
• 2019

This study evaluated the properties of Coal gasification slag(CGS) according to the CGS contents of cement mortar condition as a basic step to examine the applicability of CGS as concrete fine aggregate. Flow increased with increasing CGS contents for both Crushed sand a(CSa) and Crushed sand b+Sea sand(CSb+SS), but the amount of air contents decreased to the opposite tendency. Based on 28 days is maximum compressive strength was obtained at CGS 50% when CSa was used and CGS 75% when CSb+SS. The flexural strength were the maximum at 25% and 50% of CGS, but the tendency was similar to the compressive strength. Compared with CSa, the compressive strength and flexural strength 5% higher than those of CSb+SS, in CGS using of were about 5% higher than those of unused CGS. As a result of comprehensive study on the quality of mortar according to the CGS contents, it can be concluded that when CGS is mixed with fine aggregate at about 50%, it can contribute to securing workability and strength development positively so that resource recycling and quality improvement can be achieved at the same time.

• Journal of Korea Society of Waste Management
• /
• v.35 no.7
• /
• pp.616-626
• /
• 2018

The quality standards of solid refuse fuel (SRF) define the values for 12 physico-chemical properties, including moisture, lower heating value, and metal compounds, according to Article 20 of the Enforcement Rules of the Act on Resource Saving and Recycling Promotion. These parameters are evaluated via various SRF Quality Test Methods, but problems related to the heavy metal content have been observed in the microwave acid digestion method. Therefore, these methods and their applicability need improvement. In this study, the appropriate testing conditions were derived by varying the parameters of microwave acid digestion, such as microwave power and pre-treatment time. The pre-treatment of SRF as a function of the microwave power revealed an incomplete decomposition of the sample at 600 W, and the heavy metal content analysis was difficult to perform under 9 mL of nitric acid and 3 mL of hydrochloric acid. The experiments with the reference materials under nitric acid at 600 W lasted 30 minutes, and 1,000 W for 20 or 30 minutes were considered optimal conditions. The results confirmed that a mixture of SRF and an acid would take about 20 minutes to reach $180^{\circ}C$, requiring at least 30 minutes of pre-treatment. The accuracy was within 30% of the standard deviation, with a precision of 70 ~ 130% of the heavy metal recovery rate. By applying these conditions to SRF, the results for each condition were not significantly different and the heavy metal standards for As, Pb, Cd, and Cr were satisfied.

• The Journal of Engineering Geology
• /
• v.33 no.4
• /
• pp.737-753
• /
• 2023

Abandoned mines represent unused space resulting from resource use and changes in industrial environments. Efforts are underway to repurpose such underground spaces, leveraging their unique attributes of temperature stability, shading, and security. This study aimed to assess the feasibility of operating high-demand data centers and public sports facilities as potential recycling options for abandoned mine spaces. The status of data centers located in abandoned mines abroad was examined, including their operational technology capitalizing on the advantages of underground spaces. Considering the varying sizes of underground spaces in different types of abandoned mine in South Korea, the suitability of installing facilities for 12 different sports was evaluated for potential contributions to the health and welfare of local residents. The utilization of abandoned mine spaces as data centers and public sports facilities is expected to not only recycle industrial heritage but also to allow new development opportunities for local communities.

• Clean Technology
• /
• v.30 no.2
• /
• pp.113-122
• /
• 2024

In order to better understand carbon dioxide recycling, the carbon dioxide capture characteristics of six different alkaline industrial by-products, including incineration ash, desulfurized gypsum, low-grade quicklime, and steelmaking slag were investigated using a laboratory-scale direct aqueous carbonation reactor. In addition to the dissolution characteristics of each sample, the main reaction structure was confirmed through thermogravimetric analysis before and after the reaction, and the reactive CaO content was also defined through thermogravimetric analysis. The carbon dioxide capture capacity and efficiency of quicklime were determined to be 473 g/kg and 86.9%, respectively, and desulfurized gypsum and incineration ash were also evaluated to be relatively high at 51.1 to 131.7 g/kg and 51.2 to 87.7%, respectively. On the other hand, the capture efficiency of steelmaking slag was found to be less than 10% due to the influence of the production and post-cooling conditions. Therefore, in order to apply the carbonation process to steelmaking slag, it is necessary to optimize the slag production conditions. Through this study, it was confirmed that the carbon dioxide capture characteristics of incineration ash, quicklime, and desulfurized gypsum are at levels suitable for carbonation processes. Furthermore, this study was able to secure basic data for resource development technology that utilize carbon dioxide conversion to produce calcium carbonate for construction materials.