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Stability Analysis of Concrete Plugs Installed in Pilot Tunnels for the Storage of Compressed Air (압축공기 저장용 파일롯 터널에 설치된 콘크리트 플러그의 안정성 해석)

  • Lee, Youn-Kyou;Song, Won-Kyoung;Park, Chul-Whan;Choi, Byung-Hee
    • Tunnel and Underground Space
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    • v.20 no.6
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    • pp.446-454
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    • 2010
  • CAES-G/T (Compressed Air Energy Storage - Gas Turbine) power generation is a likely option for the buffer facility stabilizing the fluctuation of the renewable powers, such as wind and solar powers. Considering the geological conditions, the underground CAES facility is most probable if the CAES-G/T generation is planed in Korea. In this kind of facility, a concrete plug is installed to seal the compressed air in the container, so that the selection of the shape and dimension of concrete plug could be a critical design factor. The stability evaluation of two types of plug was carried out by investigating the distribution of the factor of safety in the plugs and the distribution of contact pressure over the contact surface. The analysis result shows that the taper-shaped plug is more structurally stable than the wedge-shaped plug for the given geological condition. Possible separation of the rock-concrete interface around the spring line of the wedge-shaped plug is anticipated, which means the possible leakage of compressed air through the side wall and also means the poor mobilization of frictional resistance on that area.

Skull Reconstruction with Custom Made Three-Dimensional Titanium Implant

  • Cho, Hyung Rok;Roh, Tae Suk;Shim, Kyu Won;Kim, Yong Oock;Lew, Dae Hyun;Yun, In Sik
    • Archives of Craniofacial Surgery
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    • v.16 no.1
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    • pp.11-16
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    • 2015
  • Background: Source material used to fill calvarial defects includes autologous bones and synthetic alternatives. While autologous bone is preferable to synthetic material, autologous reconstruction is not always feasible due to defect size, unacceptable donor-site morbidity, and other issues. Today, advanced three-dimensional (3D) printing techniques allow for fabrication of titanium implants customized to the exact need of individual patients with calvarial defects. In this report, we present three cases of calvarial reconstructions using 3D-printed porous titanium implants. Methods: From 2013 through 2014, three calvarial defects were repaired using custom-made 3D porous titanium implants. The defects were due either to traumatic subdural hematoma or to meningioma and were located in parieto-occipital, fronto-temporo-parietal, and parieto-temporal areas. The implants were prepared using individual 3D computed tomography (CT) data, Mimics software, and an electron beam melting machine. For each patient, several designs of the implant were evaluated against 3D-printed skull models. All three cases had a custom-made 3D porous titanium implant laid on the defect and rigid fixation was done with 8 mm screws. Results: The custom-made 3D implants fit each patient's skull defect precisely without any dead space. The operative site healed without any specific complications. Postoperative CTs revealed the implants to be in correct position. Conclusion: An autologous graft is not a feasible option in the reconstruction of large calvarial defects. Ideally, synthetic materials for calvarial reconstruction should be easily applicable, durable, and strong. In these aspects, a 3D titanium implant can be an optimal source material in calvarial reconstruction.

CONSIDERATIONS REGARDING ROK SPENT NUCLEAR FUEL MANAGEMENT OPTIONS

  • Braun, Chaim;Forrest, Robert
    • Nuclear Engineering and Technology
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    • v.45 no.4
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    • pp.427-438
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    • 2013
  • In this paper we discuss spent fuel management options in the Republic of Korea (ROK) from two interrelated perspectives: Centralized dry cask storage and spent fuel pyroprocessing and burning in sodium fast reactors (SFRs). We argue that the ROK will run out of space for at-reactors spent fuel storage by about the year 2030 and will thus need to transition centralized dry cask storage. Pyroprocessing plant capacity, even if approved and successfully licensed and constructed by that time, will not suffice to handle all the spent fuel discharged annually. Hence centralized dry cask storage will be required even if the pyroprocessing option is successfully developed by 2030. Pyroprocessing is but an enabling technology on the path leading to fissile material recycling and burning in future SFRs. In this regard we discuss two SFR options under development in the U.S.: the Super Prism and the Travelling Wave Reactor (TWR). We note that the U.S. is further along in reactor development than the ROK. The ROK though has acquired more experience, recently in investigating fuel recycling options for SFRs. We thus call for two complementary joint R&D project to be conducted by U.S. and ROK scientists. One leading to the development of a demonstration centralized away-fromreactors spent fuel storage facility. The other involve further R&D on a combined SFR-fuel cycle complex based on the reactor and fuel cycle options discussed in the paper.

Bilateral Chylothorax Due to Blunt Spine Hyperextension Injury: A Case Report

  • Lee, Hohyoung;Han, Sung Ho;Lee, Min Koo;Kwon, Oh Sang;Kim, Kyoung Hwan;Kim, Jung Suk;Chon, Soon-Ho;Shinn, Sung Ho
    • Journal of Trauma and Injury
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    • v.32 no.2
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    • pp.107-110
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    • 2019
  • Bilateral chylothorax due to blunt trauma is extremely rare. We report a 74-year-old patient that developed delayed bilateral chylothorax after falling off a ladder. The patient had a simple 12th rib fracture and T12 lamina fracture. All other findings seemed normal. He was sent home and on the 5th day visited our emergency center at Halla Hospital with symptoms of dyspnea and lower back pain. Computer tomography of his chest presented massive fluid collection in his right pleural cavity and moderate amounts in his left pleural cavity with 12th rib fracture and T11-12 intervertebral space widening with bilateral facet fractures. Chest tubes were placed bilaterally and chylothorax through both chest tubes was discovered. Conservative treatment for 2 weeks failed, and thus, thoracic duct ligation was done by video assisted thoracoscopic surgery. Thoracic duct embolization was not an option. Postoperatively, the patient is now doing well and happy with the results. Early surgical treatment must be considered in the old patient, whom large amounts of chylothorax are present.

Treatment of Freiberg's Disease Using the Shortening Effect of the Modified Weil Osteotomy (변형 Weil 절골술의 중족지 단축 효과를 이용한 Freiberg병의 치료)

  • Lee, Tae-Hoon;Lee, Yeong-Hyeon;Ahn, Gil-Yeong;Nam, Il-Hyun;Lee, Kyung-Jin;Woo, Sang-Won
    • Journal of Korean Foot and Ankle Society
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    • v.25 no.4
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    • pp.165-170
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    • 2021
  • Purpose: This study sought to evaluate the clinical effectiveness of the shortening effect of the modified Weil osteotomy for the treatment of Freiberg's disease. Materials and Methods: We reviewed 21 cases treated with the modified Weil osteotomy for Freiberg's disease from November 2005 to June 2019. The average follow-up period was 32.5 months and the mean age of the patients was 38.3 years. The clinical results were analyzed using the American Orthopaedic Foot and Ankle Society (AOFAS) lesser metatarsophalangeal-interphalangeal scale, the visual analogue scale (VAS), and the range of motion (ROM) of the metatarsophalangeal joint. In the radiologic evaluation, the length of preoperative and postoperative metatarsal shortening was compared. Results: The average AOFAS lesser metatarsophalangeal-interphalangeal scale showed an improvement from 60.5 preoperatively to 90.9 at the latest follow-up. VAS showed a decrease from 5.4 preoperatively to 0.9 at the latest follow-up. ROM of the affected metatarsophalangeal joint increased from 40.2 degrees preoperatively to 58.6 degrees at the latest follow-up. The mean length of metatarsal shortening was 6.7 mm. There was no transfer metatarsalgia, osteonecrosis, and definite joint space narrowing. Conclusion: Modified Weil osteotomy with second layer cutting is an effective treatment option to restore the joint surface and painless joint motion for patients with Freiberg's disease.

WALANT: A Discussion of Indications, Impact, and Educational Requirements

  • Shahid, Shahab;Saghir, Noman;Saghir, Reyan;Young-Sing, Quillan;Miranda, Benjamin H.
    • Archives of Plastic Surgery
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    • v.49 no.4
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    • pp.531-537
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    • 2022
  • Wide-awake, local anesthesia, no tourniquet (WALANT) is a technique that removes the requirement for operations to be performed with a tourniquet, general/regional anesthesia, sedation or an anesthetist. We reviewed the WALANT literature with respect to the diverse indications and impact of WALANT to discuss the importance of future surgical curriculum integration. With appropriate patient selection, WALANT may be used effectively in upper and lower limb surgery; it is also a useful option for patients who are unsuitable for general/regional anesthesia. There is a growing body of evidence supporting the use of WALANT in more complex operations in both upper and lower limb surgery. WALANT is a safe, effective, and simple technique associated with equivalent or superior patient pain scores among other numerous clinical and cost benefits. Cost benefits derive from reduced requirements for theater/anesthetic personnel, space, equipment, time, and inpatient stay. The lack of a requirement for general anesthesia reduces aerosol generating procedures, for example, intubation/high-flow oxygen, hence patients and staff also benefit from the reduced potential for infection transmission. WALANT provides a relatively, but not entirely, bloodless surgical field. Training requirements include the surgical indications, volume calculations, infiltration technique, appropriate perioperative patient/team member communication, and specifics of each operation that need to be considered, for example, checking of active tendon glide versus venting of flexor tendon pulleys. WALANT offers significant clinical, economic, and operative safety advantages when compared with general/regional anesthesia. Key challenges include careful patient selection and the comprehensive training of future surgeons to perform the technique safely.

Effects of gihyeolsotong-hwan on monosodium iodoacetate-induced osteoarthritis in rats (기혈소통환(氣血疏通丸)이 Monosodium iodoacetate로 골관절염(骨關節炎)을 유도(誘導)한 랫드에 미치는 영향(影響))

  • Xu, Wen-Qiang;Kim, Soon-Keun;Choi, Hak-Joo;Kim, Dong-Hee
    • The Korea Journal of Herbology
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    • v.33 no.3
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    • pp.45-53
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    • 2018
  • Objectives : In cases of osteoarthritis, the hypofunction of the cartilage and joint leads to a limited range of joint motion, swelling, and pain, which is generally treated using pharmaceutical drugs (e.g., anti-inflammatory agents, cartilage protectants, and nonsteroidal anti-inflammatory drugs) or replacement arthroplasty. However, long-term drug treatment is associated with adverse effects on the gastrointestinal systems. The present study aimed to evaluate the ability of Giheolsotong-hwan to treat of osteoarthritis symptoms in the MIA-induced rat model based on histological analysis, and factors that are associated with inflammation and bone mineral metabolism. Methods : Giheolsotong-hwan was administered orally at doses of 200 mg/kg/day or 400 mg/kg/day for 2 weeks before direct injection of monosodium iodoacetate ($3mg/50{\mu}{\ell}$ of 0.9% saline) into the intra-articular space of the rats' right knee. The rats subsequently received the same doses of oral Giheolsotong-hwan for another 4 weeks. We evaluated the treatment effects based on serum biomarkers and histopathological analysis of the knee joints. Results : Compared to those in control rats, the Giheolsotong-hwan treatments significantly decreased the serum concentration of inflammation factors (i.e., $IL-1{\beta}$, IL-6, $TNF-{\alpha}$, $PGE_2$, and $LTB_4$), and bone degrade factors (i.e., MMP-9, CTX-II, and COMP). In addition, the Giheolsotong-hwan treatments significantly increased the concentration of glycosaminoglycans of bone defence factors, but no chage the TIMP-1. Furthermore, the Giheolsotong-hwan treatments effectively preserved the knee cartilage and proteoglycan. Conclusion : The results indicate that Giheolsotong-hwan treated osteoarthritis symptoms. Thus, Giheolsotong-hwan may be a novel oriental therapeutic option for the management of osteoarthritis.

Christian Education for the Post-Corona World (코로나 이후 세계를 위한 기독교교육)

  • Jae-Deog Yu
    • Journal of Christian Education in Korea
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    • v.72
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    • pp.7-24
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    • 2022
  • Christian education for the world after COVID-19 needs to use rapid changes in the surrounding situation as an opportunity to overcome a new crisis so that the church can achieve its educational mission. If the biggest dilemma in the post-Corona era is that there is no authoritative educational prescription anywhere, the most reasonable option for church education in this situation is to emphasize and cultivate learners' ability to flexibly cope with rules that are completely different than before COVID-19. As a natural result of the crisis, Christian education needs to be more interested in the trend of social change in the pandemic era(glocalization, digital transformation, economic inequality, educational environment change, church crisis) and actively reflect its contents in education. In addition, while operating a mobile(or online) church school that combines offline and online, there is an urgent need for an innovative transition to a core church school where certain church schools and churches cooperate with each other, a church school that guarantees a safe learning space, and an ecological church school that is interested in education dealing with climate change and ecology.

A Basic Study on Site Selection of Ocean Thermal Energy Conversion Plant in Adjacent Seas of the Korean Peninsula (I) (한국근해 해양 온도차 발전소의 입지선정에 관한 기초연구 (I))

  • Suh, Young-Sang;Jang, Lee-Hyun;Jo, Myung-Hee
    • Journal of the Korean Association of Geographic Information Studies
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    • v.1 no.2
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    • pp.44-55
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    • 1998
  • This study was carried out to investigate the feasibility of OTEC(Ocean Thermal Energy Conversion) operation, in the East Sea of Korea. Accumulated cruise data of NFRDI (National Fisheries Research and Development Institute) over the period 1966~1995 were used to locate appropriate spot by season as well as by latitude which would show the difference at least $15^{\circ}C$ or more between the surface layer and each depth of 50, 100, 150, 200, 250, 300, 400 and 500m. Our results showed that the coastal areas of Pohang city met the requirement of more than $20^{\circ}C$ difference for OTEC plant from August to October. In contrast, in case that $15^{\circ}C$ would be possible thermal difference to operate OTEC plant, most coastal areas in the East Sea including Pohang from June to December are potential candidates for this future energy source. Therefore, we present in this paper the first option to locate the best place for OTEC plant operation using Geographical Information System (GIS), which is currently used for multi-dimensional space analysis.

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The Future of Republic of Korea Navy : Toward a Korean Way of Naval Strategy (미래 대한민국 해군력 역할과 발전)

  • Choi, Joung-Hyun
    • Strategy21
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    • s.37
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    • pp.65-103
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    • 2015
  • This study is an attempt to look into the future role of the ROKN and to provide a strategic way forward with a special focus on naval strategic concept and force planning. To accomplish this goal, this research takes four sequential steps for analysis: 1) assessing the role and utility of naval power of ROKN since its foundation back in 1945; 2) forecasting features of various maritime threats to influence the security of Korea in the future directly or indirectly; 3) identifying the roles to be undertaken by future ROKN; and 4) recommending Korean way of naval force planning and the operational concept of naval power. This study seeks to show that ROKN needs comprehensive role to better serve the nation with respect to national security, national prosperity and development, and future battle-space management. To safeguard the national security of Korea, it suggests three roles: 1) national guard for the peaceful unification; 2) protector of the maritime sovereignty; and 3) suppressor to maritime threats. Three more roles are highlighted for national prosperity: 1) escort of the national economy; 2) guardian for national maritime activities; and 3) contributor to the world peace. These roles need to be closely connected with the role for the battle-space management. This paper addresses the need for a dramatic shift of the central operational domain from land to maritime in the future. This will eventually offer future ROKN a leading role for developing strategic concept and force planning rather than merely a supporting one. This study finally suggests 'balanced' strategy both in concept development and force planning. A balanced force planning is a 'must' rather than an 'option' when considering a division of function between Task Fleets and Area Fleets, constructing cutting-edge conventional forces such as Aegis destroyer, CVs, or submarines, and the mix of high-profile platform and low-profile when composing future fleets. A 'balance' is also needed in operational concept. The fleet should be prepared to fulfill its missions based on two different types of force operation i.e., coercive or cooperative application of the utility of naval force. The findings and recommendations of the study are relevant today, and will be increasingly important in the future to achieve various political goals required by enhancing the utility of naval power.