• Journal of the Korean Institute of Gas
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• v.27 no.1
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• pp.63-69
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• 2023

Although Korea is the world's No. 1 semiconductor producing country, most studies are conducted with risk assessment for simple material risks due to the closedness of the site for industrial protection. In terms of industrial safety, a monitoring system such as a gas detector to determine the leakage of hazardous substances has been established, but research on effectively discharging harmful gastritis substances in case of leakage has only recently begun. Semiconductor manufacturing facilities (gas boxes) where a large amount of flammable materials are handled are currently being safety managed by using a gas detector and blocking the air inlet. It is difficult to dilute in a short time in case of leakage of flammable substances. Therefore, in this study, based on various criteria, the size of the duct according to the size of the gas box is determined and the appropriate size of the air inlet is studied to minimize the exhaust performance requirement without exposing hazardous chemicals to the outside in the event of a flammable leak. We want to do an optimal exhaust design.

• Composites Research
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• v.21 no.1
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• pp.16-21
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• 2008

The cure behavior of epoxy resin with a conventional amide-type hardener(HD) was investigated in the presence of castor oil(CO), cashew nut shell liquid(CNSL) and CNSL-formaldehyde resin(CFR) by using a dynamic differential scanning calorimetry(DSC). The activation energy of curing reaction was also calculated based on the non-isothermal DSC thermograms at various heating rates. An one-stage curing was noted in the case of epoxy resin filled with CO, while the epoxy resin with CNSL and CFR showed a two-stage curing process. A competitive cure reaction was noted for the epoxy resin/CNSL(or CFR)/HD blends. In the absence of HD, the CFR showed lower values of curing enthalpy than that of CNSL. The activation energy of epoxy resin curing increased with increasing the CNSL and CFR loading.

• Journal of the Korean Institute of Gas
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• v.27 no.2
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• pp.65-70
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• 2023

Flammable materials used in semiconductor supply facilities are manufactured at high temperatures and high pressures, and as the semiconductor industry becomes more sophisticated and larger, the amount of materials used is rapidly increasing. Recently, fires and explosions occurred during the handling of acetic acid, which is a raw material for making products in the semiconductor material manufacturing process. Overall problems such as lack of air inflow prevention for fire and explosion prevention were identified. Therefore, in this study, in order to accurately identify the cause of the accident and prevent fire and explosion that may occur in the process of handling large amounts of flammable liquids, opinions from various perspectives, such as construction of facilities such as hoppers, installation of AOPS components, and change in workers' perceptions would like to present.

• International conference on construction engineering and project management
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• 2013.01a
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• pp.403-411
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• 2013

Horizontal construction projects such as oil and gas pipeline projects typically involve repetitive-work activities with the same crew and equipment from one end of the project to the other. Repetitive scheduling also known as linear scheduling is known to have superior schedule management capabilities specifically for such horizontal construction projects. This study discusses on expanding the capabilities of repetitive scheduling to account for the variance in production rates and visual representation by developing an automated alignment based linear scheduling program for applying temporal and spatial changes in production rates. The study outlines a framework to apply changes in productions rates when and where they will occur along the horizontal alignment of the project and illustrates the complexity of construction through the time-location chart through a new linear scheduling model, Linear Scheduling Model with Varying Production Rates (LSM_VPR). The program uses empirically derived production rate equations with appropriate variables as an input at the appropriate time and location based on actual 750 mile natural gas liquids pipeline project starting in Wyoming and terminating in the center of Kansas. The study showed that the changes in production rates due to time and location resulted in a close approximation of the actual progress of work as compared to the planned progress and can be modeled for use in predicting future linear construction projects. LSM_VPR allows the scheduler to develop schedule durations based on minimal project information. The model also allows the scheduler to analyze the impact of various routes or start dates for construction and the corresponding impact on the schedule. In addition, the graphical format lets the construction team to visualize the obstacles in the project when and where they occur due to a new feature called the Activity Performance Index (API). This index is used to shade the linear scheduling chart by time and location with the variation in color indicating the variance in predicted production rate from the desired production rate.

• Composites Research
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• v.37 no.1
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• pp.21-31
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• 2024

This review paper investigates the use of shockwave attenuating materials within composite structures to enhance personnel protection against blast-induced traumatic brain injury (bTBI). This paper also introduces experimental methodologies exploited in the generation and measurement of shockwaves to evaluate the performance of the shock dissipating composites. The generation of shockwaves is elucidated through diverse approaches such as high-energy explosives, shock tubes, lasers, and laser-flyer techniques. Evaluation of shockwave propagation and attenuation involves the utilization of cutting-edge techniques, including piezoelectric, interferometer, electromagnetic induction, and streak camera methods. This paper investigates phase-separated materials, including polyurea and ionic liquids, and provides insight into composite structures in the quest for shockwave pressure attenuation. By synthesizing and analyzing the findings from these experimental approaches, this review aims to contribute valuable insights to the advancement of protective measures against blast-induced traumatic brain injuries.

• Korean Journal of Organic Agriculture
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• v.28 no.3
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• pp.387-403
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• 2020

This experiment was carried out to determine optimal concentration of organic liquids for the improvement of antioxidant in pepper. As human beings enter the age of 100, they are naturally recognized as a standard of high quality agricultural products for safety and improvement of functional materials. Tomatoes are among the most consumed vegetables in the world and there is a growing interest in varieties with high functional content. However, there is a limit to the improvement of functional materials of certain varieties, so it is necessary to study the improvement of materials by cultivation physiology and environmental conditions. The test material was sown on March 15th in Wanju province and on June 15th in rain shelter house using pepper "suppermanidda" varieties. To investigate the optimum concentration of organic liquids for the improvement of antioxidant, 15 kinds of treatments were carried out including control, tomato liquid fertilizer etc. The liquid fertilizer of organic material was treated with 6 times of irrigation, and the analysis of nutrients and antioxidant was done by harvesting pepper on the September 10th. The contents of beta-carotene was increased in the T3, T4, T12 treatments, vitamin C was in the P14 treatments, flavonoid, polyphenol were in the P12 treatment compared to the control. In T12 treatment, flavonoid increased by 115.9%, polyphenol by 121.7%, beta-carotene by 117.2% and vitamin C by 136.1% compared to the control. There was no significant difference in the growth characteristics and characteristics of pepper fruit of pepper according to liquid fertilizer treatment. Therefore, it has been confirmed that the organic antioxidant is affected by the liquid fertilizer treatments of organic materials and it is necessary to study the environmental conditions such as temperature, moisture and photosynthesis.

• Applied Biological Chemistry
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• v.15 no.1
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• pp.65-75
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• 1972

The rice qualities including cooking and eating qualities were studied using recommended Korean rice varieties (20 of japonica and 3 of indies type; IR 667) which were grown at Suwon, Korea in 1971. As the result, followings were obtained. 1. Amylose contents of white rice were varied with the varieties 21.1 to 25.5% and the average was 23.0%. Three indica type varieties (IR 667) showed higher amylose contents than the other japonica type varieties except Mankyung. Among japonica type varieties, Palkum, Mankyung composed the group of the highest amyloes content and Kimmaje was the lowest. 2. Blue values were distributed in the range of 0.38 to 0.48 and the average was 0.42 IR 667 varieties showed the highest blue value among them. Among japonica type varieties, Jaegun showd the highest blue value and Sooseung, Shirogane showed successively lower values, Shin #2, Nongbaik, Palkweng, Suwon #82, Mankyung, Nonglim #25 and Nongkwang relatively lower blue values. 3. Alkali numbers were in the range of 6.0 to 7.4 and the average was 6.8. Much difference was not shown in alkali number between IR 667 group and the japonica varieties group. 4. Gelatinization temperature were ranged from 59.5 to 64.0 IR 667 varieties showed relatively higher gelatinization temperature than japonica type varieties. 5. Water uptake ratios were measured in the range of 2.67 to 2.92 and the average was 2.79. IR 667 varieties were belonged to the group of highest water uptake ratio. Among japonica type varieties Kimmaje, Suwon #82, Nonglim #29, Deungpan #5, Jaegun, Jinhung, were belonged to the group of relatively high water uptake ratio and Palkweng, Palkeum and Paldal to the relatively low water uptake ratio. 6. Expaned volums were ranged from 29.8 to 33.7 and the average was 31.8. IR 667 varieties showed higher expanded volumes than japonica type varieties. 7. Intensities of starch-iodine blue value of residual liquid indicated 0.35 to 0.58. Among them IR 667 varieties showed relatively high intensities. 8. The range of total solids in residual liquids was 0.605 to 0.810 and the average was 0.700 Much difference was not shown in total solids in residual liquid between IR 667 varieties and japonica varieties. 9. pH values of residual liquids were in the range of 6.3 to 7.3 and the average was 6.95. IR 667 varieties showed lower pH than japonira type varieties.

• Resources Recycling
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• v.17 no.6
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• pp.62-67
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• 2008

Oil shale is a sedimentary rock that contains organic compounds called kerogen that are released as petroleum-like liquids by retorting. In order to evalute oil shale as alternative oil resources, the physical properties of oil shale samples from US and Russia were investigated and Fischer assays were carried out. Thermogravimetric analysis shows that thermal degradation of oil shale consisted of two stage processes, with hydrocarbon release from kerogen followed by $CO_2$ release by carbonate decomposition. Organic compounds in oil shale have an high hydrogen/carbon ratio, and therefore liquid hydrocarbons could be obtained easily. Shale oil yields from Russian and US oil shales by Fischer assay were 12.7% and 18.5%, respectively. The density and boiling point of shale oils are higher than that of Middle East crude oil, indicating that further upgrading processes are necessary for refinery. On the other hands, sulfur contents are relatively low, and the amounts of Vanadium and Nickel are extremely small in shale oil. It was found that paraffins were rich in US shale oil while main components of Russian shale oil were oxygenated hydrocarbons.

• Korean Chemical Engineering Research
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• v.48 no.5
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• pp.583-588
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• 2010

Esterification of free fatty acid with methanol to biodiesel was investigated in a batch reactor using various solid acid catalysts, such as polymer cation-exchanged resins with sulfuric acid functional group(Amberlyst-15, Dowex 50Wx8), acidic ionic liquids (ILs)-modified silica gels respectively with $-SO_3H$ and $-SO_2Cl$ functional group ($SiO_2-[ASBI][HSO_4]$, $SiO_2-[ASCBI][HSO_4]$) and grafted silica gels respectively with $-SO_3H$ and $-SO_2Cl$ functional group ($SiO_2-R-SO_3H$, $SiO_2-R-SO_2Cl$). The effects of reaction time, temperature, reactant concentration(molar ratio of methanol to oleic acid), and catalyst amount were studied. Allylimidazolium-based ILs on modified silica gels were superior to other tested solid acid catalysts. Especially, the performance of $SiO_2-[ASBI][HSO_4]$ (immobilized by grafting of 3-allyl-1-(4-sulfobutyl)imidazolium hydrogen sulfate on silica gel) was better than that of a widely known Amberlyst-15 catalyst at the same reaction conditions. A high conversion yield of 96% was achieved in the esterification reaction of the simulated cooking oil at 353 K for 2 h. The high catalytic activity of $SiO_2-[ASBI][HSO_4]$ was attributed to the presence of strong Brønsted acid sites from the immobilized functional groups. The catalyst was recovered and the biodiesel product was separated by simple processes such as decantation and filtration.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.226.1-226.1
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• 2010

본연구에서는 GTL(gas to liquids)공정의 합성가스 생산을 위해 수증기-이산화탄소 복합개질반응(Combined Steam and Carbon dioxide Reforming of Methane, CSCRM)을 수행하였다. CSCRM은 수증기와 이산화탄소의 공급비 조절을 통해 $H_2$/CO비를 2로 맞추기 용이한 장점을 지니고 있어 다른 단일 개질 반응과 달리 합성가스 생산 시 $H_2$/CO 비율을 조절하기 위한 부가적인 공정이 필요하지 않아 경제적인 공정이다. 일반적으로 사용되는 Ni개질촉매는 가격대비 우수한 성능을 보이지만 S/C비가 낮은 CSCRM의 경우 촉매표면의 탄소침적에 의한 비활성화가 야기되는 문제점이 있다. 따라서 본 연구에서는 산소저장능력과 산소전달능력이 우수한 $CeO_2$를 조촉매로 첨가하여 표면에 형성된 코크 제거가 용이하도록 하였다. Ni-Ce/$MgAl_2O_4$촉매는 동시함침법(co-impregnation)으로 제조하였으며, Ni의 함량을 10wt%로 고정한 상태에서 Ce의 함량을 조절하여 Ce/Ni 최적비를 찾고자 하였다. XRD, TPR, BET, $H_2$-Chemisorption과 같은 촉매의 특성분석을 통해 촉매의 비표면적, 환원특성과 Ni입자의 분산도 등을 확인하였다. Ce를 첨가함에 따라 Ce2.5wt%까지는 비표면적이 증가하다가 이후 점차 줄어드는 경향성을 보였다. 또한, $H_2$-Chemisorption 결과 역시 비표면적과 유사한 경향성을 보였는데, Ce5.0wt%까지 Ni 분산도가 증가 하다가 다시 감소하는 것을 확인할 수 있었다. 반응실험은 $H_2O:CO_2:CH_4:N_2$ = 0.8:0.4:1:1의 공급조건에서 수행하였으며, 질소와 수소 환원분위기로 $700^{\circ}C$에서 1시간 환원 후 $650^{\circ}C$에서 $550^{\circ}C$범위로 온도를 떨어뜨려가면서 반응을 수행하였다. Ce를 첨가함에 따라 $CH_4$ 전환율이 증가를 하다가 Ce2.5wt% 이후 감소하는 것을 확인할 수 있었다. 이러한 높은 촉매 활성은 Ce 첨가로 인해 환원특성이 좋아지고 Ni분산도가 증가하여 담체와 강한 상호작용(SMSI)을 형성함으로 탄소침적 저항성 강화에 기인한 것이다.