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A Study on the Thermal Crack Control of Foundation for Large Turbine (대형 터빈 기초 구조물의 온도균열 제어에 관한 연구)

  • Ha, Ju-Hyung;Cho, Yun-Gu;Lee, Kewn-Chu;Lim, Chang-Keun
    • Journal of the Korea Concrete Institute
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    • v.26 no.3
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    • pp.287-297
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    • 2014
  • Heat of hydration of mass concrete is one of the most important factors that significantly affect structural quality and construction period. Therefore, appropriate methods to control heat of hydration are essential technologies for mass concrete construction. In this study, probability of thermal cracking was checked by thermal analysis prior to the construction of a turbine foundation in a domestic power plant. Subsequently, changes of concrete mix proportion and an effective curing method were proposed to control heat of hydration of mass concrete structures. Concrete manufactured by slag cement was proposed instead of concrete produced by ordinary Portland cement, and an automated curing method was proposed to improve the curing method using typical moist curing with blanket. The automated curing method maintains the temperature difference between center and surface of concrete below a setting value by temperature monitoring. Concrete with slag cement was used for actual construction. One of two identical turbine foundations was cured by an insulated curing method, and the other was cured by the automated curing method to compare the curing methods. And then, the effects of control of heat of hydration were evaluated based on temperature/strain monitoring and crack investigations.

Biodegradation of a Reactive Dye, Remazol Black B in a UASB Reactor (UASB 반응기를 이용한 반응성 염료 Remazol Black B의 분해)

  • Oh, You-Kwan;Lee, Sung-Ho;Kim, Hyo-Seob;Kim, Yu-Jin;Lee, Sang-Joon;Park, Sung-Hoon
    • KSBB Journal
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    • v.14 no.6
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    • pp.688-695
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    • 1999
  • Biodegradation of the reactive dye, Remazol Black B was investigated in an upflow anaerobic sludge blanket(UASB) reactor. Important parameters studied include dye concentration(20-60 mg/L), glucose concentration as a co-substrate(1,000-3,000 mg/L), hydraulic retention time(3-24 hr), and influent pH(6.0-8.0). Under most conditions tested, the molecules of Black B were degraded readily and completely according to HPLC chromatograms. However, the color removal efficiency based on spectroscopic measurement was always approximately 75%. This suggests that the degradation products have some color intensity corresponding to 25% of the original dye molecules. The maximum influent dye concentration which satisfies the legal discharge limit of color intensity of 400 ADMI was 13 mg/L. and the highest removal rate at this dye concentration was 104 mg/L${\cdot}$day.

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On the Leakage Safety Analysis of $9\%$ Nickel Type LNG Storage Tank with Thermal Resistance Effects (열저항 효과를 고려한 $9\%$ 니켈강재식 LNG 저장탱크의 누설 안전성에 관한 연구)

  • Kim C.K.;Cho S.H.;Suh H.S.;Hong S.H.;Lee S.R.;Kim Y,G.;Kwon B.K.
    • Journal of the Korean Institute of Gas
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    • v.9 no.1 s.26
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    • pp.1-8
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    • 2005
  • In this study, the FE analysis has been presented for the leakage safety of $9\%$ nickel type LNG storage tank based on the thermal resistance effects between insulation panels, comer protection and prestressed concrete(PC) structures. The FEM calculated results show that the leakage safety of fiber glass blanket, perlite powder and cellular glass insulators does not guarantee any more due to a strength failure of the insulation structure. But the corner protection and PC structure of outer tank may delay or sustain the leaked LNG of 10 days even though the inner tank and insulation structure are simultaneously failed. This means that $9\%$ nickel steel type LNG storage tank may be safe because of a high strength of the corner protection and outer tank structures.

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A survey on the nonpharmacologic nursing intervention for children in pain (통증 환아를 위한 비약물적 간호 중재 방법 조사)

  • Yoon Hea Bong;Cho Kyoul Ja
    • Child Health Nursing Research
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    • v.6 no.2
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    • pp.144-157
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    • 2000
  • This study was done to understand nonpharmacologic pain management for pediateric patients and nurses' knowledge and attitudes toward it. The aim of this study was that which method did the patient's use according to the nurses' age, and how did they effectively use these methods in their field. The subjects of this study were 77 nurses working in the Pediatric unit in the Kyung Medical Center from September 2 to 15, 1999 using questionnaire form. The results of this study were as follows : 1. We divided the subjects into four groups : Younger than one year old, 1-6 years, 6-12 years, 12-18 years group. In the group younger one year old, most of the nurses participating in this study used speaking in soft quiet tones, supportive touch, toys, pacifiers. In the group of 1-6 years, they used speaking in soft quiet tones, toys, distracting attention, story talking, and visual stimulus. In the group of 6-12 years. they used pop-up books, providing information, cold therapy, speaking in soft quiet tones, supportive touch. In the group of 12-19 years, most of them used providing information, controling respiration and supportive touch. 2. The effective nursing intervention used in their field are speaking in soft quiet tones, pacifiers and nesting with blanket in the group of younger than one year old. Un the group of 1-6 years old, speaking in soft quiet tones, toys, and supportive touch were effective method in the control of nonp-harmacologic pain management. In the group of 6-12 years old, story talking, supportive touch, and speaking in soft quiet tones were effective method and in the group of 12-18 years old, providing information, cold therapy and supportive touch were effectively used to control nonpharmacologic pain management. 3. To compare the general characteristics and non-pharmacologic pain nursing intervention, in the group of younger than one year, touching stimuli is widely used. In the groups of 1-6, and 6-12 years old, visual and audio method were widely used. In the group of 12-18 years old, sensitive intervention were used as well as education, information and guided imagery. In conclusion, there was no significant difference in nurses' demographic characteristics, child's age and nonpharmacologic pain management. There was significant difference only in the nurses working area, that is nurses working in the surgical department used more audio-visual-tactile pain management methods than medical department.

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Titanium Hemostatic Clip Tailoring Method to Overcome Vessel Caliber Discrepancy in Interposition Saphenous Vein Graft for Carotid Artery Resection (경동맥 절제술 후 재건에 사용된 복재정맥의 혈관구경 불일치를 극복하기 위한 Titanium Hemostatic Clip 봉합방법)

  • Kim Sun-Ho;Lim Young-Chang;Lee Sei-Young;Lim Jae-Yol;Choi Eun-Chang
    • Korean Journal of Head & Neck Oncology
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    • v.20 no.2
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    • pp.177-180
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    • 2004
  • Objectives: To completely excise a malignant tumor which invades carotid artery walls, the resection and reconstruction of the carotid artery is essentially required. In most of the cases, interposition graft using a saphenous vein has been performed, however the vessel caliber discrepancy between a common carotid artery and the saphenous vein can result in a problem on surgical technique. We have introduced and evaluated a new titanium hemoclip tailing method to overcome vessel caliber discrepancy in interposition saphenous vein graft for carotid artery resection in the treatment of head and neck cancers. Method: After carotid artery resection, the calibers of the proximal common carotid artery and the vein were compared, and an orifice of the common carotid artery was gradually reduced to a little larger than or the same size as the orifice of the vein by using the titanium hemostatic clip. Subsequently, the common carotid artery was connected to the vein through anastomosis. The same method was also applied to the distal anastomosis site. There after, the vessels were connected through the anastomosis, and a circulation was restored by releasing a vascular clamp. Then, a titanium hemostatic clip-applied redundant portion on the outside of carotid artery was sutured by the blanket edge suture method, using 6-0 Prolene. Results: We have experienced this method in two patients with recurrent squamous cell carcinoma and neuroblostoma, respectively. The interposition saphenous vein graft of these patients was found to maintain good patency on the follow up angiography after one year, and they had no specific vascular complication, such as atherosclerosis. Conclusion: This method made it possible to simply perform the interposition saphenous vein graft (ISVG) within a short time and, therefore, was very useful for shortening the duration to block circulation.

Effect of F/R ratio of ASBR (Anaerobic Sequencing Batch Reactor) Process on Removal of the Organic Matters in Ammonia Stripped Swine Wastewater (ASBR(Anaerobic Sequencing Batch Reactor) 공정의 F/R비가 암모니아가 탈기된 축산폐수의 유기물 제거에 미치는 영향)

  • Whang, Gye-Dae;Cho, Young-Moo
    • Journal of Korean Society on Water Environment
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    • v.21 no.6
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    • pp.687-694
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    • 2005
  • Lab-scale experiments have been carried out to investigate the effect of F/R ratio of ASBR (Anaerobic Sequencing Batch Reactor) process on the removal of the organic matters in ammonia stripped swine wastewater. Three ASBR inoculated with sludge mixed with granular sludge of UASB (Upflow Anaerobic Sludge Blanket) and anaerobic digested sludge of municipal wastewater treatment plant were operated. Ammonia stripped swine wastewater was used as influent. Prior to conducting the experiments with varied conditions, the effect of increasing organic loading rate from 2.34 to $5.79gTCOD_{Cr}/L$-day at a fixed F/R ratio of 0.1 on the organic removal efficiency has been studied during start-up period. As the result of the experiment, under the condition of varied organic loadings, less than $4.14gTCOD_{Cr}/L$-day, the removed efficiency $TCOD_{Cr}$ of the ASBR process is 83% resulted from the mean value of effluent $TCOD_{Cr}$, 9,125 mg/L during the start-up period. Then ASBRs were operated with F/R ratio of 0.024, 0.303 and 0.91 respectively. Organic loading rate was increased from 4.56 to $15.43gTCOD_{Cr}/L$-day to investigate the effects of F/R ratio and organic loading rate on the organic removal efficiency. As the result of the experiment, less than $6.23gTCOD_{Cr}/L$/L-day, F/R ratio haven't an effect on the organic removal efficiency and the mean removal efficiency of TSS, $TCOD_{Cr}$ and $SCOD_{Cr}$ was about 80%, 86% and 78% at the all of F/R ratio. But as organic loading rate was increased from 8.54 to $12.04gTCOD_{Cr}/L$-day at the F/R ratio of 0.024, the removal efficiency of $SCOD_{Cr}$ decreased from 71% to 63%. The range of decreased removal efficiency of $SCOD_{Cr}$ at the F/R ratio of 0.024 was much more higher than at the F/R ratio of 0.303, 0.91. Thus, as organic loading rate was increased, ASBRs were operated with high F/R ratio to obtain high removal efficiency.

Treatment of Landfill Leachate using H2O2/O3 AOP and UASB Process (I) - Treatment Characteristics of Leachate depending on H2O2/O3 AOP Pretreatment and Available Nitrogen Form - (H2O2/O3 AOP와 UASB 공정을 이용한 매립지 침출수 처리(I) - H2O2/O3 AOP 전처리 및 질소원에 따른 침출수별 처리특성 -)

  • Jeong, Seung Hyun;Jeong, Byung Gon
    • Journal of Korean Society on Water Environment
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    • v.21 no.6
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    • pp.643-650
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    • 2005
  • In order to treat leachate from aged landfill site effectively, removal of biologically recalcitrant organic matter and denitrification efficiency were evaluated through the combination of $H_2O_2/O_3$ AOP pretreatment process and UASB process. The results can be summarized as follows. In case of leachate having low COD/N ratio from aged landfill site, it is possible to increase available COD for denitrification in nitrate utilizing denitrification and nitrite utilizing denitrification both by enhancing biodegradability of recalcitrant organic matter as applying $H_2O_2/O_3$ AOP to pretreatment process. In this experiment, it is found that available COD for denitrification can be increased to 1.0 and 0.4 g/day, respectively. Comparison has been made between requiring COD and available COD for denitrification in each experimental stages. It is expected that high rate of denitrification can be achieved with leachate from young landfill site because higher amount of available COD for denotrification is present in the leachate than the amount of requiring COD for denitrification. Especially, In leachate from aged landfill site with low COD/N ratio, it can be concluded that denitrification using nitrite nitrogen can enhance overall denitrification performance efficiently because denitrification using nitrite nitrogen requires less amount of carbon source than denitrification using nitrate nitrogen. Comparing the biogas production rate and nitrogen content of biogas under the condition of same amount of nitrate and nitrite addition, biogas production and nitrogen content of biogas are increased during denitrification after $H_2O_2/O_3$ AOP pretreatment process. Therefore, it can be confirmed that COD/N ratio in the leachate is increased. Applying $H_2O_2/O_3$ AOP as pretreatment system of landfill leachate seems to have little economic benefit because it requires additional carbon source to denitrify ammonia nitrogen in leachate coming from aged landfill site. However, it is possible to apply this pretreatment process to leachate from old landfill site in view of AOP process can achieve removal of biologically recalcitrant organic matter and increase of available COD for denitrification simultaneously.

Simultaneous Carbon and Nitrogen Removal Using an Integrated System of High-Rate Anaerobic Reactor and Aerobic Biofilter (고효율 혐기성반응조 및 호기성여상 조합시스템에 의한 질소·유기물 동시 제거)

  • Sung, Moon Sung;Chang, Duk;Seo, Seong Cheol;Chung, Bo Rim
    • Journal of Korean Society of Water and Wastewater
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    • v.13 no.2
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    • pp.55-65
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    • 1999
  • AF(anaerobic filter)/BAF(biological aerated filter) system and UASB(upflow anaerobic sludge blanket)/BAF system, of which system effluents were recirculated to the anaerobic reactors in each system, were operated in order to investigate the performance in simultaneous removal of organics and nitrogen in high-strength dairy wastewater. Advanced anaerobic treatment processes of AF and UASB were evaluated on applicability as pre-denitrification reactors, and BAF was also evaluated on the performance in oxidizing the remaining organics and ammonia nitrogen. At system HRTs of 4.0 to 4.5 days and recirculation ratios of one to three, the AF/BAF system could achieve more than 99% of organics removals and 64 to 78% of total nitrogen removals depending upon the recirculation ratio. Although the UASB/BAF system also showed more than 99% of organics removals, total nitrogen removals in the UASB/BAF system were 53 to 66% which are lower than those in the AF/BAF system at the corresponding recirculation ratios. Optimum recirculation ratios considering simultaneous removal of organics and nitrogen and cost-effectiveness, were in the range of two to three. The upflow AF packed with crossflow module media, as a primary treatment of the anaerobic reactor/BAF system, showed better performances in denitrification, SS removals, and gas production than the UASB. Higher loading rate of suspended solids from the UASB increased the backwashing times in the following BAF. Especially, at a recirculation ratio of three in the UASB/BAF system, the increase in head loss due to clogging in the BAF caused frequent backwashing, at least once d day. The BAF showed the high nitrification efficiency of average 99.2% and organics removals more than 90% at organics loading rate less than $1.4KgCOD/m^3/d$ and $COD/NH_3-N$ ratio less than 6.4. It was proved that the simplified anaerobic reactor/BAF system could maximize the organics removal and achieve high nitrogen removal efficiencies through recirculation of system effluents to the anaerobic reactor. The AF/BAF system can, especially, be a cost effective and competitive alternative for the simultaneous removal of organics ana nitrogen from wastewaters.

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Consent for using human biological material in research: based on the revised Bioethics and Safety Act (인체유래물연구에 대한 동의 소고(小考) - 개정 생명윤리법 제42조의2를 계기로 -)

  • Lee, Dongjin;Lee, Sun Goo
    • The Korean Society of Law and Medicine
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    • v.20 no.2
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    • pp.111-140
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    • 2019
  • The Bioethics and Safety Act provides a set of rules to regulate biobanks and research activities using human biological material, but the law seems to be defective in several folds. The law requires that, prior to collection or use of human biological materials, researchers should obtain the informed consent of the donors, but the law does not obligate biobanks to do so. Even in cases where the law requires informed consent, the ordinance of the Ministry of Health and Welfare allows open (or blanket) consent. In addition, a new article in the Act, Article 42-2 which will take effect from October 24, 2019, allows medical institutions to provide biobanks with remaining biospecimens collected in the course of diagnosis and treatment, unless the donors express their intent to opt-out, without obtaining specific consent from them. Given the need to protect the autonomy of donors and the unique characteristics of biobanks and research activities that use human biological materials, this paper concludes that such open consent-based law may not be suitable to protect the autonomy of the donors and that the broad consent requirement may be a desirable policy option. The paper acknowledges that the international community has long questioned whether broad consent (as well as open consent) is an effective choice to regulate the use of human biological materials. The paper stresses that the baseline requirement in designing the law is that the secondary use of human biological materials should be based on informed consent of the donors; the core value of the law should be a governance structure that promotes transparency and protects donor participation.

Improvement of Insulation System for LNG Storage Tank Base Slab (LNG 저장탱크 바닥판 단열 시스템 개선)

  • Lee, Yong-Jin;Lho, Byeong-Cheol
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.14 no.4
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    • pp.141-147
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    • 2010
  • Liquefied natural gas(LNG) is natural gas that has been converted temporarily to liquid form for ease of storage and transport it. Natural gas is the worlds cleanest burning fossil fuel and it has emerged as the environmentally preferred fuel of choice. In Korea, the demand of this has been increased since the first import from the Indonesia in 1986. LNG takes up about 1/600th the volume of natural gas in the gaseous state by cooling it to approximately $-162^{\circ}C(-260^{\circ}F)$. The reduction in volume therefore makes it much more cost efficient to transport and store it. Modern LNG storage tanks are typically the full containment type, which is a double-wall construction with reinforced concrete outer wall and a high-nickel steel inner tank, with extremely efficient insulation between the walls. The insulation will be installed to LNG outer tank for the isolation of cryogenic temperature. The insulation will be installed in the base slab, wall and at the roof. According to the insulation's arrangement, the different aspects of temperature transmission is shown around the outer tank. As the result of the thermal & stress analysis, by the installing cellular glass underneath the perlite concrete, the temperature difference is greatly reduced between the ambient temperature and inside of concrete wall, also reducing section force according to temperature load.