The safety related components in the nuclear power plant should be designed to withstand the seismic load. Among these components the integrity of reactor internals under earthquake load is important in stand points of safety and economics, because these are classified to Seismic Class I components. So far the modelling methods of reactor internals have been investigated by many authors. In this paper, the dynamic behaviour of reactor internals of Yong Gwang 1&2 nuclear power plants under SSE(Safe Shutdown Earthquake) load is analyzed by using of the simpled Global Beam Model. For this, as a first step, the characteristic analysis of reactor internal components are performed by using of the finite element code ANSYS. And the Global Beam Model for reactor internals which includes beam elements, nonlinear impact springs which have gaps in upper and lower positions, and hydrodynamical couplings which simulate the fluid-filled cylinders of reactor vessel and core barrel structures is established. And for the exciting external force the response spectrum which is applied to reactor support is converted to the time history input. With this excitation and the model the dynamic behaviour of reactor internals is obtained. As the results, the structural integrity of reactor internal components under seismic excitation is verified and the input for the detailed duel assembly series model could be obtained. And the simplicity and effectiveness of Global Beam Model and the economics of the explicit Runge-Kutta-Gills algorithm in impact problem of high frequency interface components are confirmed.
Journal of the Korean Society of Marine Environment & Safety
/
v.29
no.4
/
pp.363-371
/
2023
To construct a ship, blocks of various sizes must be moved and erected . In this process, lugs are used such that they match the block fastening method and various functions suitable for the characteristics of each shipyard facility. The sizes and shapes of the lugs vary depending on the weight and shape of the block structures. The structure is reinforced by welding the doubling pads to compensate for insufficient rigidity around the holes where the shackle is fastened. As for the method of designing lugs according to lifting loading conditions, a simple calculation based on the beam theory and structural analysis using numerical modeling are performed. In the case of the analytical method, a standardized evaluation method must be established because results may differ depending on the type of element and modeling method. The application of this ambiguous methodology may cause serious safety problems during the process of moving and turning-over blocks. In this study , the effects of various parameters are compared and analyzed through numerical structural analysis to determine the modeling conditions and evaluation method that can evaluate the actual structural response of the lug. The modeling technique that represents the plate part and weld bead around the lug hole provides the most realistic behavior results. The modeling results with the same conditions as those of the actual lug where only the weld bead is connected to the main body of the lug, showed a lower ulimated strength compared with the results obtained by applying the MPC load. The two-dimensional shell element is applied to reduce the modeling and analysis time, and a safety working load was verified to be predicted by reducing the thickness of the doubling pad by 85%. The results of the effects of various parameters reviewed in the study are expected to be used as good reference data for the lug design and safe working load prediction.
Jaehoon Choi;SunJu Park;Hyunsoo Seo;Hyun Tai Ahn;Jeong-Hwan Lee;Junghoon Park;Seong-Taek Yun
Economic and Environmental Geology
/
v.56
no.6
/
pp.847-870
/
2023
The safe disposal of high-level radioactive waste requires accurate predictions of the long-term geochemical behavior of radionuclides. To achieve this, the present study was conducted to model geochemical behaviors of uranium (U), plutonium (Pu), and palladium (Pd) under different hydrogeochemical conditions that represent deep groundwater in Korea. Geochemical modeling was performed for five types of South Korean deep groundwater environment: high-TDS saline groundwater (G1), low-pH CO2-rich groundwater (G2), high-pH alkaline groundwater (G3), sulfate-rich groundwater (G4), and dilute (fresh) groundwater (G5). Under the pH and Eh (redox potential) ranges of 3 to 12 and ±0.2 V, respectively, the solubility and speciation of U, Pu, and Pd in deep groundwater were predicted. The result reveals that U(IV) exhibits high solubility within the neutral to alkaline pH range, even in reducing environment with Eh down to -0.2 V. Such high solubility of U is primarily attributed to the formation of Ca-U-CO3 complexes, which is important in both G2 located along fault zones and G3 occurring in granitic bedrocks. On the other hand, the solubility of Pu is found to be highly dependent on pH, with the lowest solubility in neutral to alkaline conditions. The predominant species are Pu(IV) and Pu(III) and their removal is predicted to occur by sorption. Considering the migration by colloids, however, the role of colloid formation and migration are expected to promote the Pu mobility, especially in deep groundwater of G3 and G5 which have low ionic strengths. Palladium (Pd) exhibits the low solubility due to the precipitation as sulfides in reducing conditions. In oxidizing condition, anionic complexes such as Pd(OH)3-, PdCl3(OH)2-, PdCl42-, and Pd(CO3)22- would be removed by sorption onto metal (hydro)oxides. This study will improve the understanding of the fate and transport of radionuclides in deep groundwater conditions of South Korea and therefore contributes to develop strategies for safe high-level radioactive waste disposal.
The reliable estimation of pile bearing capacity is essential for the improvement of the re- liability and the cost-effectiveness of the design. There have been numerous pile bearing capacity prediction methods proposed up to now, however, execpt for the estimation made from the result of the pile loading test, not one method is appropriate for the reliable prediction. Due to the considerable time and expenses required to carry out the pile loading test, the test has seldom been utilized. The development of Simple Pile Loading Test(SPLT) which utilizes the pile skin friction as the required reaction force to cause the pile tip settlement, provides a solution to perform more pile loading tests and consequently a more economical pile design is possible. The separate measurement of skin friction and tip resistance during the course of performing SPLT provides a better understanding of the pile behavior than the result of the conventional pile loading test where only the total resistance is measured. On the other hand, there are some points to be clarified in order to apply the test results of SPLT to practical problem. They are the direction of the applied load to mobilize the skin friction and the use of reduced sized sliding core. In this research, both the SPLT and the conventional pile loading test on 406mm diameter steel pipe pile have been performed. From the result, it would be safe to use the measured SPLT skin friction value directly in the design, since the value is somewhat lower than the value measured in the conventional test. It is further assumed that the tip resistance value of the reduced sized sliding core should properly be analysed by taking the incluonce of scale effect into consideration.
The Journal of Korea Assosiation for Disability and Oral Health
/
v.13
no.2
/
pp.80-85
/
2017
Angelman syndrome is a rare disorder caused by deletion or inactivation of genes on the maternally inherited chromosome 15. This neurodevelopmental disorder is characterized by developmental and intellectual delay, speech impairment, sleep disturbance, seizures, motor dysfunction, and frequent laughing or smiling. Orofacial characteristics include a prominent mandible, large mouth, prominent cheeks, a tendency to rest the tongue between the dental arches, excessive drooling, and excessive chewing behavior. Patients with this syndrome usually require general anesthesia even in a simple operation, because of risk of perioperative seizure during dental procedure. This is a case report about dental treatment of a 3-year-old female patient with Angelman syndrome under general anesthesia. This case suggests that the dental treatment under general anesthesia can be considered a safe component for the uncooperative, delayed developmental patients with underlying disease. Also, periodic dental exam appointment should be made to provide the patients with preventive treatments and to make them remain familiar with the dental environment.
Recently, researches about fiber reinforced polymer (FRP) which has excellent durability, corrosion resistance, and tensile strength as a substitution material to steel tendon have been actively pursued. This study is performed to examine FRP tendon used prestressed beam's safety under service load. The specimen was a prestressed concrete beam with internal bonded FRP tendon. In order to compare the member fatigue capacity, a control specimen of a prestressed concrete beam with ordinary steel tendon was tested. A fatigue load was applied at a load range of 60%, 70%, and 80% of the 40% ultimate load, which was obtained though a static test. The fatigue load was applied as a 1~3 Hz sine wave with 4 point loading setup. Fatigue load with maximum 1 million cycles was applied. The specimen applied with a load ranging between 40~60% did not show a fatigue failure until 1 million cycles. However, it was found that horizontal cracks in the direction of tendons were found and bond force between the tendon and concrete was degraded as the load cycles increased. This fatigue study showed that the prestressed concrete beam using FRP tendon was safe under a fatigue load within a service load range. Fatigue strength of the specimen with FRP and steel tendon after 1 million cycles was 69.2% and 59.8% of the prestressed concrete beam's static strength, respectively.
Kim, Ji-Eun;Moon, Ji-Hea;Shin, Hyun-Ah;Lee, Ji-Sun;Kwon, Sung-Hee;Lee, Jung-Sook;Om, Ae-Son
Culinary science and hospitality research
/
v.17
no.3
/
pp.141-150
/
2011
The objective of this study is to monitor the microbiological effect on preschool children's hand safety according to educational methods of hand washing. The subjects were ten children aged three to five. The analyses of the microbiological effect were made before band washing education, after one-week video demonstrations of hand washing education, and after one-week video demonstrations of hand washing education combined with practice. The results were as follows. Total plate count, filamentous fungi, coliform, and Staphylocuccus aureus were detected from children's hands just before band washing education. According to the two-week hand washing education, such education was found effective in keeping the children's hands clean and safe. In conclusion, repeated and more consistent training of band washing would be important for children, especially aged three to five because most of the habits and behavior patterns were developed in these age groups and the effects were persistent during their future life.
Childhood obesity has rapidly increased in Korea during the past 20-30 years. Approximately 1 of 10 children and adolescents is obese. Appropriate prevention and intervention measures urgently need. Obesity prevention starts early in life, i.e., obesity prevention and education begins during the period of fetal development in utero. Behavioral changes are the most positively reflected during pregnancy. Infants should be fed breast milk, and inculcated with healthy eating and behavioral habits during infancy to ultimately establish a healthy lifestyle in children. For achieving a lifestyle and behavior that successfully allow children to overcome obesity, although individual motivation is important, active support of parents and family members is also imperative. Health care providers should also make an effort to actively prevent obesity and take necessary intervention actions. Although the efforts of individuals, family, and healthy care providers are important to prevent the rapid increase in obesity, primary prevention should be encouraged at a higher level. Schools should specifically aim at improving nutrition and physical activity by allocating times for healthy eating, playing, and physical education. Moreover, local communities should provide support by funding for safe recreational environments, such as playgrounds and walking tracks. Public health strategies in community and national policies, such as city planning, food marketing, and advertisements, are required for primary prevention of obesity.
Many a number of policies have been tried to reduce auto accidents so far, but it is obvious that further studies are still needed to find a more fundamental and multi-dimensional preventive measure with effect. The National Mental Health Statistics shows that the most profound forms of negative emotions, that is, depression and anxiety, have been increasing, but studies on such a topic are scarce to find. Therefore, we conducted a structural analysis between the negative emotions, including depression and anxiety, of drivers and their driving behaviors using a Structural Equation Modeling(SEM) technique. The review of past literature and studies indicated that not all of human emotions manifest themselves as the ultimate behaviors because they go through emotion regulation Strategies. For this reason, the purpose of this study was set to analyze the structural model developed in this study reflecting the emotion regulation strategies. The result of our analysis showed that the driver's negative emotion had a more significant influence on dangerous driving behaviors than safe ones, and especially, the expressive suppression strategy was found to be the highest factor. Also, the total effect analysis with the negative emotional factors showed that expressive suppression had more significant influence compared to that of cognitive reappraisal. The implication of this study might provide a better understanding on driving behaviors of the drivers and could be used as a fundamental study for future policy development to reduce traffic accidents.
Lee, Chan Hee;Chung, Youn Sam;Kim, Ji Young;Yi, Jeong Eun
Journal of Conservation Science
/
v.17
s.17
/
pp.83-94
/
2005
Host rock or the standing sculptured Buddha in the Yongamsa temple is macular porphyritic biotite granite, which has gone through mechanical and chemical weathering. The rock around the Buddha statue is busily scattered with steep inclinations that are almost vertically discontinuous planes with the strikes of $N8^{\circ}E$. Especially the development of the joints that cross the major joints causes the structural instability of the rock. The rock of the Buddha statue is separated into several rock blocks because of many different discontinuity. Thus it is estimated that the bed rock has not only plane and toppling failure but also wedge failure in all the sides. Since the differential pressure is imposed on the body of the Buddha in the host rock, it is urgent to give a reinforce treatment of geotechnical engineering for the safe of its structural stability. Very contact area of joints have turned into soil, which promotes the growth of weeds and plant roots, then aggravates the mechanical weathering of the rock. Thus conservational treatments should also be considered to get rid of secondary contaminants and vegetation along the discontinuities and to prevent further damages.
본 웹사이트에 게시된 이메일 주소가 전자우편 수집 프로그램이나
그 밖의 기술적 장치를 이용하여 무단으로 수집되는 것을 거부하며,
이를 위반시 정보통신망법에 의해 형사 처벌됨을 유념하시기 바랍니다.
[게시일 2004년 10월 1일]
이용약관
제 1 장 총칙
제 1 조 (목적)
이 이용약관은 KoreaScience 홈페이지(이하 “당 사이트”)에서 제공하는 인터넷 서비스(이하 '서비스')의 가입조건 및 이용에 관한 제반 사항과 기타 필요한 사항을 구체적으로 규정함을 목적으로 합니다.
제 2 조 (용어의 정의)
① "이용자"라 함은 당 사이트에 접속하여 이 약관에 따라 당 사이트가 제공하는 서비스를 받는 회원 및 비회원을
말합니다.
② "회원"이라 함은 서비스를 이용하기 위하여 당 사이트에 개인정보를 제공하여 아이디(ID)와 비밀번호를 부여
받은 자를 말합니다.
③ "회원 아이디(ID)"라 함은 회원의 식별 및 서비스 이용을 위하여 자신이 선정한 문자 및 숫자의 조합을
말합니다.
④ "비밀번호(패스워드)"라 함은 회원이 자신의 비밀보호를 위하여 선정한 문자 및 숫자의 조합을 말합니다.
제 3 조 (이용약관의 효력 및 변경)
① 이 약관은 당 사이트에 게시하거나 기타의 방법으로 회원에게 공지함으로써 효력이 발생합니다.
② 당 사이트는 이 약관을 개정할 경우에 적용일자 및 개정사유를 명시하여 현행 약관과 함께 당 사이트의
초기화면에 그 적용일자 7일 이전부터 적용일자 전일까지 공지합니다. 다만, 회원에게 불리하게 약관내용을
변경하는 경우에는 최소한 30일 이상의 사전 유예기간을 두고 공지합니다. 이 경우 당 사이트는 개정 전
내용과 개정 후 내용을 명확하게 비교하여 이용자가 알기 쉽도록 표시합니다.
제 4 조(약관 외 준칙)
① 이 약관은 당 사이트가 제공하는 서비스에 관한 이용안내와 함께 적용됩니다.
② 이 약관에 명시되지 아니한 사항은 관계법령의 규정이 적용됩니다.
제 2 장 이용계약의 체결
제 5 조 (이용계약의 성립 등)
① 이용계약은 이용고객이 당 사이트가 정한 약관에 「동의합니다」를 선택하고, 당 사이트가 정한
온라인신청양식을 작성하여 서비스 이용을 신청한 후, 당 사이트가 이를 승낙함으로써 성립합니다.
② 제1항의 승낙은 당 사이트가 제공하는 과학기술정보검색, 맞춤정보, 서지정보 등 다른 서비스의 이용승낙을
포함합니다.
제 6 조 (회원가입)
서비스를 이용하고자 하는 고객은 당 사이트에서 정한 회원가입양식에 개인정보를 기재하여 가입을 하여야 합니다.
제 7 조 (개인정보의 보호 및 사용)
당 사이트는 관계법령이 정하는 바에 따라 회원 등록정보를 포함한 회원의 개인정보를 보호하기 위해 노력합니다. 회원 개인정보의 보호 및 사용에 대해서는 관련법령 및 당 사이트의 개인정보 보호정책이 적용됩니다.
제 8 조 (이용 신청의 승낙과 제한)
① 당 사이트는 제6조의 규정에 의한 이용신청고객에 대하여 서비스 이용을 승낙합니다.
② 당 사이트는 아래사항에 해당하는 경우에 대해서 승낙하지 아니 합니다.
- 이용계약 신청서의 내용을 허위로 기재한 경우
- 기타 규정한 제반사항을 위반하며 신청하는 경우
제 9 조 (회원 ID 부여 및 변경 등)
① 당 사이트는 이용고객에 대하여 약관에 정하는 바에 따라 자신이 선정한 회원 ID를 부여합니다.
② 회원 ID는 원칙적으로 변경이 불가하며 부득이한 사유로 인하여 변경 하고자 하는 경우에는 해당 ID를
해지하고 재가입해야 합니다.
③ 기타 회원 개인정보 관리 및 변경 등에 관한 사항은 서비스별 안내에 정하는 바에 의합니다.
제 3 장 계약 당사자의 의무
제 10 조 (KISTI의 의무)
① 당 사이트는 이용고객이 희망한 서비스 제공 개시일에 특별한 사정이 없는 한 서비스를 이용할 수 있도록
하여야 합니다.
② 당 사이트는 개인정보 보호를 위해 보안시스템을 구축하며 개인정보 보호정책을 공시하고 준수합니다.
③ 당 사이트는 회원으로부터 제기되는 의견이나 불만이 정당하다고 객관적으로 인정될 경우에는 적절한 절차를
거쳐 즉시 처리하여야 합니다. 다만, 즉시 처리가 곤란한 경우는 회원에게 그 사유와 처리일정을 통보하여야
합니다.
제 11 조 (회원의 의무)
① 이용자는 회원가입 신청 또는 회원정보 변경 시 실명으로 모든 사항을 사실에 근거하여 작성하여야 하며,
허위 또는 타인의 정보를 등록할 경우 일체의 권리를 주장할 수 없습니다.
② 당 사이트가 관계법령 및 개인정보 보호정책에 의거하여 그 책임을 지는 경우를 제외하고 회원에게 부여된
ID의 비밀번호 관리소홀, 부정사용에 의하여 발생하는 모든 결과에 대한 책임은 회원에게 있습니다.
③ 회원은 당 사이트 및 제 3자의 지적 재산권을 침해해서는 안 됩니다.
제 4 장 서비스의 이용
제 12 조 (서비스 이용 시간)
① 서비스 이용은 당 사이트의 업무상 또는 기술상 특별한 지장이 없는 한 연중무휴, 1일 24시간 운영을
원칙으로 합니다. 단, 당 사이트는 시스템 정기점검, 증설 및 교체를 위해 당 사이트가 정한 날이나 시간에
서비스를 일시 중단할 수 있으며, 예정되어 있는 작업으로 인한 서비스 일시중단은 당 사이트 홈페이지를
통해 사전에 공지합니다.
② 당 사이트는 서비스를 특정범위로 분할하여 각 범위별로 이용가능시간을 별도로 지정할 수 있습니다. 다만
이 경우 그 내용을 공지합니다.
제 13 조 (홈페이지 저작권)
① NDSL에서 제공하는 모든 저작물의 저작권은 원저작자에게 있으며, KISTI는 복제/배포/전송권을 확보하고
있습니다.
② NDSL에서 제공하는 콘텐츠를 상업적 및 기타 영리목적으로 복제/배포/전송할 경우 사전에 KISTI의 허락을
받아야 합니다.
③ NDSL에서 제공하는 콘텐츠를 보도, 비평, 교육, 연구 등을 위하여 정당한 범위 안에서 공정한 관행에
합치되게 인용할 수 있습니다.
④ NDSL에서 제공하는 콘텐츠를 무단 복제, 전송, 배포 기타 저작권법에 위반되는 방법으로 이용할 경우
저작권법 제136조에 따라 5년 이하의 징역 또는 5천만 원 이하의 벌금에 처해질 수 있습니다.
제 14 조 (유료서비스)
① 당 사이트 및 협력기관이 정한 유료서비스(원문복사 등)는 별도로 정해진 바에 따르며, 변경사항은 시행 전에
당 사이트 홈페이지를 통하여 회원에게 공지합니다.
② 유료서비스를 이용하려는 회원은 정해진 요금체계에 따라 요금을 납부해야 합니다.
제 5 장 계약 해지 및 이용 제한
제 15 조 (계약 해지)
회원이 이용계약을 해지하고자 하는 때에는 [가입해지] 메뉴를 이용해 직접 해지해야 합니다.
제 16 조 (서비스 이용제한)
① 당 사이트는 회원이 서비스 이용내용에 있어서 본 약관 제 11조 내용을 위반하거나, 다음 각 호에 해당하는
경우 서비스 이용을 제한할 수 있습니다.
- 2년 이상 서비스를 이용한 적이 없는 경우
- 기타 정상적인 서비스 운영에 방해가 될 경우
② 상기 이용제한 규정에 따라 서비스를 이용하는 회원에게 서비스 이용에 대하여 별도 공지 없이 서비스 이용의
일시정지, 이용계약 해지 할 수 있습니다.
제 17 조 (전자우편주소 수집 금지)
회원은 전자우편주소 추출기 등을 이용하여 전자우편주소를 수집 또는 제3자에게 제공할 수 없습니다.
제 6 장 손해배상 및 기타사항
제 18 조 (손해배상)
당 사이트는 무료로 제공되는 서비스와 관련하여 회원에게 어떠한 손해가 발생하더라도 당 사이트가 고의 또는 과실로 인한 손해발생을 제외하고는 이에 대하여 책임을 부담하지 아니합니다.
제 19 조 (관할 법원)
서비스 이용으로 발생한 분쟁에 대해 소송이 제기되는 경우 민사 소송법상의 관할 법원에 제기합니다.
[부 칙]
1. (시행일) 이 약관은 2016년 9월 5일부터 적용되며, 종전 약관은 본 약관으로 대체되며, 개정된 약관의 적용일 이전 가입자도 개정된 약관의 적용을 받습니다.