• Journal of Korean Society of Water and Wastewater
• /
• v.13 no.1
• /
• pp.43-50
• /
• 1999

In spite of low energy requirement, and operation and construction cost, biofilters with soil beds have not been operated efficiently. Because of excess moisture in winter and rainy periods, saturated pores in the bed prevent passage and sorption of odorous compounds. Sometimes this results in septic conditions that release previously sorbed and oxidized sulfur. Therefore, an economical and effective alternative needs to be developed. The objectives of this study were to confirm applicability of the granular scrap tires with compost for treating odorous gas as well as to obtain optimum design parameters for proposed system. In lab-scaled test, multiple stage reactors had lower headloss than a single stage reactor and less headloss was occurred for the gas with higher moisture content. For practical purpose, pilot-scaled reactor was operated to remove odor from septic tank, manure and animal wastewater treatment plant and composting machine. According to the results of pilot scaled test, $H_2S$ can be always removed completely and ammonia/amine can be removed excellently when proper moisture content is provided. The results from lab and pilot test showed that granular scrap tire could be replaced with soil as supporting material for biofilter showed excellent drainage because of its ability to reject moisture.

• Journal of the Korean Society for Railway
• /
• v.17 no.1
• /
• pp.43-51
• /
• 2014

In the earth structures of railways, large coarse granular materials are widely used as fill materials. However, experimental studies that consider the dynamic properties of these coarse granular materials have rarely been carried out in Korea due to the lack of a large scale test apparatus in this country. In this study, large scale cyclic triaxial tests were carried out for materials such as reinforced roadbed (subballast, graded crushed stone), transition zone gravel, and the upper subgrade of a railway. These specimens were prepared according to certain conditions (dry unit weight, grain size distribution, and so on) specified in the Korea railroad design standard. Based on these large triaxial test results, normalized shear modulus and damping ratio curves according to small strain level are suggested. A model and coefficients for each material are also proposed.

• Environmental Engineering Research
• /
• v.19 no.3
• /
• pp.289-292
• /
• 2014

The effect of carbon dioxide ($CO_2$) on global warming is serious problem. The adsorption with solid sorbents is one of the most appropriate options. In this study, the most interesting adsorbent is granular activated carbon (GAC). It is suitable material for $CO_2$ adsorption because of its simple availability, many specific surface area, and low-cost material. Afterwards, GAC was impregnated with chitosan solution as impregnated granular activated carbon (CGAC) in order to improve the adsorption capacity of GAC. This research aims to compare the physical and chemical characteristics of GAC and CGAC. The experiment was carried out to evaluate the efficiency of $CO_2$ adsorption between GAC and CGAC. The results indicated that the iodine number of GAC and CGAC was 137.17 and 120.30 mg/g, respectively. The Brunauer-Emmett-Teller results (BET) of both GAC and CGAC show that specific surface area was 301.9 and $531.3m^2/g$, respectively; total pore volume was 0.16 and $0.29cm^3/g$, respectively; and mean diameter of pore was 2.18 and 2.15 nm, respectively. Finally, the $CO_2$ adsorption results of both GAC and CGAC in single column how the maximum adsorption capacity was 0.17 and 0.25 mol/kg, respectively; how degeneration time was 49.6 and 80.0 min, respectively; and how the highest efficiency of $CO_2$ adsorption was 91.92% and 91.19%, respectively.

• Electrical & Electronic Materials
• /
• v.16 no.1
• /
• pp.59.1-59
• /
• 2003

• Electrical & Electronic Materials
• /
• v.16 no.1
• /
• pp.60.1-60
• /
• 2003

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2007.05a
• /
• pp.70-70
• /
• 2007

• Journal of Environmental Science International
• /
• v.15 no.6
• /
• pp.579-586
• /
• 2006

The purposes of this paper were to monitor the temperature rising courses and spark discharge of the modified granular activated carbon (GAC) by microwave (MW) irradiation and to evaluate absorption of benzene. The GAC coated on $SiO_2$, boron, talc, ferrite was named as the modified GAC. Thermal and spark discharge measurement of virgin GAC and modifed GAC has been carried out using a MW device operating at 2450 MHz under various energy conditions. The results of this paper as follows. First, the modified GAC is more efficient than the virgin GAC in temperature control. Temperature gradient of the modified GAC is more lower than that of virgin GAC. The temperature gradient of GAC was observed in the following order : virgin GAC, Mn-Zn ferrite/GAC, Ni-Zn ferrite,/GAC, $SiO_2/GAC$, Boron/GAC, Talc/GAC. Second, the spark discharge of the modified GAC was diminished, compared with that of virgin GAC. Because of its excellent electrical insulating properties, the coating material prevents the spark discharge. Finally, the benzene adsorption capacity of the modified GAC decreased due to diminishing of adsorption site by the coating material. Considering the temperature gradient and spark discharge of GAC, the GAC coated $SiO_2$ would be appropriate absorbent under irradiation of MW.

• Journal of the Korean Geotechnical Society
• /
• v.21 no.2
• /
• pp.85-91
• /
• 2005

This paper investigates P-S (load-settlement) relationship for the end-bearing Pile in granular material using the CRISP FE Program with the laboratory 2D model pile load test. In order to simulate the effect of end-bearing pile problem in the FEA, the author adopts several forms of slip element around the pile length and the pile tip. Through this study it was found that e degree of non-associated Plastic flow rule incoporated into the Mohr-Coulomb model for the end-bearing pile with the slip elements was a dominant factor in terms of numerical solution convergence. In contrast, the roller boundary used along the pile shaft showed a smooth convergence with respect to the degree of non-associated plastic flow rule.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2009.03a
• /
• pp.136-145
• /
• 2009

Factors influencing shear behavior of granular material include particle size, shape, distribution, relative density, particle crushing, etc. In this study, these factors are characterized by viewpoint of shear behavior using numerical analysis based on DEM. Geometrical particle shape is represented by a combination of small circular particles and influence of particle shape on crushing is studied through relative comparisons between clump (uncrushable) and cluster (crushable) models which are modeled using DEM. Also, particle shape is quantified by the dimensionless parameters such as circularity and convexity. The results indicate that particle shape indexes have a negative association with internal friction angle. Also, internal friction angle becomes reduced and failure envelop curve becomes nonlinear due to the particle crushing. It is also found that numerical results are quite good agreement with the experimental test conducted in this study.

• Journal of Environmental Science International
• /
• v.17 no.1
• /
• pp.129-133
• /
• 2008

This study is an endeavor to evaluate the safety of medicines from heavy metals, prescribed on the basis of herbal medicinal system and oriental medical prescription which are circulated much recently. For that, three globular types, four extract granular types and four liquid types of herbal medicine were bought to compare and analyze the content of heavy metals, such as As, Pb, Cd and Hg, which are harmful to human body. The concentration of Pb was found to be 0.552 ppm in Sachiltang, 2.552 ppm in Anjungjogiwhan and 1.735 ppm in Cheongsangbohwawhan in case of pill type herbal medicine, and liquid type herbal medicine, Maekmundongtang was 0.002 ppm, Galgeuntang was 0.003 ppm, Sangwhatang was 0.004 ppm, 20jeon Daebotang was 0.0185 ppm. And the concentration of Pb was found to be 0.322 ppm in Banhasasimtang, 0.47 ppm in Eungjosan, 0.29 ppm in Yukmijihwangtang, 0.64 ppm in Socheongryongtang in case of granular type. It was found that the liquid types herbal medicines were relatively safer than three pill types of, four granular types of and four liquid types herbal medicines were tested for concentration of heavy metals. It is considered that is required in the stage of raw material treatment, manufacturing and packaging because those herbal medicines are directly taken in and absorbed into human body through the final treatment process.