• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.603-610
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• 2016

Over 12 years have passed since the first commercial operation of a Korean high-speed train. Since then, the transport capacity of the high-speed lines has become almost saturated. Therefore, studies have been carried out to increase the operating speed of the trains in order to increase their transportation capacity. This study was carried out to improve the critical speed of the KTX-Sancheon, Korean high-speed train, in order to increase its operating speed. A dynamic analysis of the KTX-Sancheon train was performed using the contact data obtained from the wheel wear profiles that were measured from a KTX-Sancheon train in commercial operation. The analysis results were verified by comparing them with the measurement acceleration data obtained from KTX-Sancheon. The suspension parameters were optimized to improve the operation speed. The critical speed of KTX-Sancheon was increased by 9.4% after the optimization by the response surface method. The optimized suspension parameters are expected to be used for the new bogie design to increase the operating speed of KTX-Sancheon from 300km/h to 350km/h.

• Land and Housing Review
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• v.15 no.1
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• pp.167-177
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• 2024

This study aimed to assess the efficacy of an adsorption process in removing organic matter and micropollutant residuals. After a full-scale water circulation system, the adsorption process was considered a post-treatment step. The system, treating anthropogenically impacted surface waters, comprises a hydro-cyclone, coagulation, flocculation, and dissolved air flotation unit. While the system generally maintained stable and satisfactory effluent quality standards over months, it did not meet the highest standard for organic matter (as determined by chemical oxygen demands). Adsorption experiments utilized two granular activated carbon types, GAC 830 and GCN 830, derived from coal and coconut-shell feedstocks, respectively. The assessment encompassed organic materials along with two notable micropollutants: acetaminophen (APAP) and acid orange 7 (AO7). Adsorption kinetics and isotherm experiments were conducted to determine adsorption rates and maximum adsorption amounts. The quantitative findings derived from pseudo-second-order kinetics and Langmuir isotherm models suggest the effectiveness of the adsorption process. The findings of this study propose the potential of employing the adsorption process as a post-treatment to enhance the treatment of contaminants that are not satisfactorily treated by conventional water circulation systems. This enhancement is crucial for ensuring the sustainability of urban water cycles.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.9
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• pp.1013-1019
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• 2007

Electronic wastes have increased tremendously. However, any reliable treatment methodologies have rarely been established. Electronic wastes have posed serious disposal problem due to their physico-chemical stability. This paper investigated the application possibility of pyrolysis for the purpose of recycling the p-CCL(phenol based Copper Clad Laminate). Thermogravimetric analysis(TGA) was used to investigate the thermal decomposition pattern of p-CCL. We elucidated the characteristics of pyrolysis by-products at operating temperatures of 280, 350 and $600^{\circ}C$. GC/MS and FT-IR were used to characterize the liquid by-products along with general characterization methods such as Ultimate Analysis, Proximate Analysis and Heating Value, whereas general characterization methods were only introduced for the solid by-products. At a heating rate of $5^{\circ}C$/min, TGA curves exhibited three decomposition stages: (1) low-temperature decomposition region$(<280^{\circ}C)$, (2) medium temperature region$(280\sim350^{\circ}C)$ and (3) high-temperature region$(>350^{\circ}C)$. The major compounds of liquid by-products at low- and medium-temperatures were accounted for by water and phenol, whereas branched phenols and furans were major compounds at high-temperatures. As the temperature increases, volatile quantities decreased but the fixed carbon increased. High heating values of solid by-products($7,400\sim7,600$ kcal/kg) would suggest that the solid by-products could be applicable as fuel. In addition, high fixed carbon but low ash content of the solid by-products offered an implication that they are capable of being upgradable for adsorbent after applying appropriate activating process.

• Korean Journal of Veterinary Research
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• v.1 no.1
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• pp.53-53
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• 1961

During the period from 1956 to 1959, a serological survey was conducted in au effort to assessing the incidence of brucellosis in various domestic animals in Korea. The following results were obtained. 1. Seventy-six dairy cattle which were imported in the year of 1956 had 9 positive reactors (11.84%). Of 1127 goats imported in 1956 and 1958, eleven(0.98%) were reactor animals. 2. In 1956, of 108 dairy cattle tested 10(9.25%) were reactors. In 1937 and 1958, a total of 155 dairy cattle examined hid ten (6.45%) positive reactors. In 1959, of 127 dairy cattle examined two were reactor animals. 3. In 1958 and 1959, 432 goats in some districts in Korea were subject to test for brucellosis and the test revealed five (1.15%) reactors. In 1958, 683 swine serum samples were examined and eleven (1.04%) were positive. In 1959, 1133 Korean cattle were tested and seven samples (0.64%) showed positive reactions. 4. In the month of July in 1939, 580 beef cattle in Cheju National Ranch and Branch were examined and 111 (19.13%) were found to be reactors. In October of the same year, 157 cattle, consisting of reactor and suspicious cattle groups, were tested, of which 71 samples reacted positive and 47 remained suspicious. 5. In December of the year of 1958, there occurred. an outbreak of brucellosis in a swine herd in the Sachon Branch Experimental Station. Seven serological tests on 438 swine serum samples were conducted, of which 122 (27.87%) were found positive. 6. Dairy cattle No. 33 and No. 35 which had been imported in 1956 and detected as highly positive, were examined for a prolonged period to follow the variation of antibody titers. A marked drop in antibody titer was seen two months after the initial test while the re-increase in titer was observer our months after the first examination.