• Title/Summary/Keyword: 한계압력

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Seismic Fragility Assessment of Liquid Storage Tanks by Finite Element Reliability Analysis (유한요소 신뢰성 해석을 통한 액체저장탱크의 지진 취약도 평가)

  • Lee, Sangmok;Lee, Young-Joo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.4
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    • pp.718-725
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    • 2017
  • A liquid storage tank is one of the most important structures in industrial complexes dealing with chemicals, and its structural damage due to an earthquake may cause a disastrous event such as the leakage of hazardous materials, fire, and explosion. It is thus essential to assess the seismic fragility of liquid storage tanks and prepare for seismic events in advance. When a liquid storage tank is oscillated by a seismic load, the hydrodynamic pressure caused by the liquid-structure interaction increases the stress and causes structural damage to the tank. Meanwhile, the seismic fragility of the structure can be estimated by considering the various sources of uncertainty and calculating the failure probabilities in a given limiting state. To accurately evaluate the seismic fragility of liquid storage tanks, a sophisticated finite element analysis is required during their reliability analysis. Therefore, in this study, FERUM-ABAQUS, a recently-developed computational platform integrated with commercial finite element and reliability analysis software packages, is introduced to perform the finite element reliability analysis and calculate the failure probability of a liquid storage tank subjected to a seismic load. FERUM-ABAUS allows for automatic data exchange between these two software packages and for the efficient seismic fragility assessment of a structure. Using this computational platform, the seismic fragility curve of a liquid storage tank is successfully obtained.

Hydrotreating for Stabilization of Bio-oil Mixture over Ni-based Bimetallic Catalysts (Ni계 이원금속 촉매에 의한 혼합 바이오오일의 안정화를 위한 수소첨가 반응)

  • Lee, Seong Chan;Zuo, Hao;Woo, Hee Chul
    • Clean Technology
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    • v.27 no.1
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    • pp.69-78
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    • 2021
  • Vegetable oils, such as palm oil and cashew nut shell liquid (CNSL), are used as major raw materials for bio-diesel in transportation and bio-heavy oil in power generation in South Korea. However, due to the high unsaturation degree caused by hydrocarbon double bonds and a high content of oxygen originating from the presence of carboxylic acid, the range of applications as fuel oil is limited. In this study, hydrotreating to saturate unsaturated hydrocarbons and remove oxygen in mixed bio-oil containing 1/1 v/v% palm oil and CNSL on monometallic catalysts (Ni and Cu) and bimetallic catalysts (Ni-Zn, Ni-Fe, Ni-Cu Ni-Co, Ni-Pd, and Ni-Pt) was perform under mild conditions (T = 250 ~ 400 ℃, P = 5 ~ 80 bar and LHSV = 1 h-1). The addition of noble metals and transition metals to Ni showed synergistic effects to improve both hydrogenation (HYD) and hydrodeoxygenation (HDO) activities. The most promising catalyst was Ni-Cu/��-Al2O3, and in the wide range of the Ni/Cu atomic ratio of 9/1~1/4, the conversion for HYD and HDO reactions of the catalysts were 90-93% and 95-99%, respectively. The tendency to exhibit almost constant reaction activity in these catalysts of different Ni/Cu atomic ratios implies a typical structure-insensitive reaction. The refined bio-oil produced by hydrotreating (HDY and HDO) had significantly lower iodine value, acid value, and kinetic viscosity than the raw bio-oil and the higher heating value (HHV) was increased by about 10%.

Study on Pattern of Civil Service Crimes and Control Plan : Focused on the Prosecutor's Office and High ranking Public Officials Crime Investigation Office (공무원 범죄의 유형과 통제방안 -검찰과 고위 공직자범죄수사처를 중심으로)

  • Kim, Taek
    • The Journal of the Convergence on Culture Technology
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    • v.7 no.3
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    • pp.59-69
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    • 2021
  • The Moon Jae-in administration insisted on reforming the prosecution for the reform of power institutions, and also tried to control the power of the prosecution through the establishment of a high-ranking public officials criminal investigation office. Then, what is the direction of the legal prosecution reform? Above all, it is a logic to drastically reduce the power of the prosecution. How to shrink it? First, it is necessary to control or check the power of prosecution and investigation that the prosecution has. Second, the key to the reform of the prosecution is perhaps to separate personnel rights from power. In order to exclude external pressure from the prosecution's personnel rights, there must be no instruction or intervention from the attorney general. To do this, the prosecutor general must go through various personnel evaluations, such as multi-faceted evaluation. Third, the essence of the High-ranking Officials Criminal Investigations Act is to deal with crimes of prosecutors, judges, police, and members of the National Assembly. It is also the core of the institutional mechanism to cover the corruption of one's family members while holding all the right to investigate, prosecution, and warrant claims, and to check the omnipresent prosecutors who have abused their right to investigate for political purposes. Then, what is necessary for the success of the high-ranking officials criminal investigation office? Above all, We think political neutrality is very necessary. The Ministry of Airborne has a very high authority of the Director. This paper intends to examine the functions and roles of the prosecution and high-ranking officials criminal investigation offices to prevent corruption. We analyzed the contents of the prosecution and the public officials criminal investigation office, and examined the limitations and problems, and the measures to control corruption in public offices.

An Analysis for the Effect of ESP/gas Lift Hybrid System on Oil Productivity (전기공저펌프/가스리프트 혼합시스템이 오일 생산성에 미치는 영향 분석)

  • Lee, Hyesoo;Iranzi, Joseph;Wang, Jihoon;Son, Hanam
    • Journal of the Korean Institute of Gas
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    • v.26 no.5
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    • pp.1-9
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    • 2022
  • Selection of a suitable artificial lift is important in terms of efficient operation and economics for oil production. In general, process of well design includes the selection of artificial lift, but the oil recovery could be enhanced by use of hybrid system combined with two types of artificial lift method according to reservoir condition for oil production. Electric submersible pump (ESP), as a presentative artificial lift method, is a manner for supplying the pressure in the lower part of oil well by using of a multi-stage centrifugal pump with an electric energy. However, there is a disadvantage that has a limit to the application period because of mechanical defection on ESP. Accordingly, it is possible to reduce the shutdown time of production well by applying the ESP/Gas lift hybrid system, which is to switch to a gas lift when an ESP is defective. This study describes the effect of ESP/gas lift hybrid system compared with ESP method for a onshore horizontal well locating in the of Permian basin, USA. As a result of study, ESP/gas lift hybrid system could make more effective productivity than ESP method. Also, we quantitatively predicted how much economic benefit would be obtained when the hybrid system was applied in the production well.

Applying the TDR for Urban Landscape Management: Focusing on the Use of REITs (도시 경관관리를 위한 개발권양도제 정책도입에 관한 연구: 리츠 접목을 중심으로)

  • Dongoh Ha;Jaeweon Yeom;Juchul Jung
    • Journal of Environmental Impact Assessment
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    • v.32 no.4
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    • pp.242-250
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    • 2023
  • The continuity of urban space is being destroyed by disorderly high-rise development caused by reckless development, and the resulting deterioration of urban landscape is emerging as a major problem. Disordered high-rise development is adversely affecting the urban environment, such as depriving residents of the basic rights of view and sunlight and privatizing the scenery that urban residents should enjoy together. In order to create a continuous urban landscape, indiscriminate high-rise development is restricted and compensation for the affected areas is needed. Various regulations have been carried out to this end, but it is difficult to overcome the pressure and damage to high-rise development by regulations alone. Accordingly, discussions have been underway to introduce a compensation system. Among them, discussions on the introduction of a 'Transfer of Development Right' (TDR) in which land ownership and development rights are separated and compensated for development rights have been drawing attention. However, in Korea, it is difficult to introduce the system due to various problems related to the separation of development rights. In order to overcome the limitations of the introduction of TDR, this paper analyzed the concepts and characteristics of 'Real Estate Investment Trusts' (REITs) and presented a policy model for the development right transfer system incorporating REITs for effective landscape management.

Determination of fluoride in fluorite mine wastewater by ion chromatography with post-wash technique (후세척-이온크로마토그래피를 이용한 형석 광산 폐수 중 플루오라이드 정량)

  • Song, Kyung-Sun;Eum, Chul-Hun;Kim, Sang-Yeon
    • Analytical Science and Technology
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    • v.19 no.5
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    • pp.383-388
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    • 2006
  • Simple post-wash method by ion chromatography (IC) was established for the rapid and precise determination of fluoride ion in wastewater from mine in fluorite mineralized area. High sulfate in sample was retained in a pre-column and less strongly held fluoride ion was transferred to the principal separation system using modified conventional IC with switching technique. An analytical column with high capacity (AS 9 HC) was used as a pre-column to retain the amount of high sulfate. A guard column (AG 14) as a separation column was used to increase the response of fluoride and reduce the system pressure. According to the recovery of fluoride ion with one detector and the observation of sulfate peak with another conductivity detector, the optimum switching time of 10-port chromatographic injector was 4.3 min. The limit of detection (S/N = 3) of fluoride in synthetic solution containing $500mg\;L^{-1}$ sulfate was $2.4{\mu}g/L$, with $25{\mu}L$ sample volume.

A critical study on the strategies of the employment policies for older people (고령자 고용정책의 대응전략에 대한 비판과 시민권(citizenship)의 원리를 통한 대한 모색)

  • Rhee, Ka-Oak;Lee, Ji-Young
    • 한국노년학
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    • v.25 no.2
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    • pp.171-193
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    • 2005
  • Nowadays, the employment policies for older people is requested to become the new form in the change of information, globalization, and aging. It is discussed, simultaneously, about an age integrated society as the full time jobs' continuation and social jobs after the full time jobs. The discussion of jobs' continuation include from institutional system to age integrated society. Social jobs include from public labor to social wages. jobs' continuation passes over stabilization, regarding it as ideal society. social jobs are interpreted it as residual welfare, excluding the meaning of social solidarity. In fact, most of the debates is overwhelmed by the logic of economy. And so they pass over the quality of life of individuals. Therefore, this study critics the employment policies for older people in the present situation and states a direction improving the quality of life older people.

Properties of stretch-activated $K^+$ channels in an G292 osteoblast-like cell (G292 세포에서 세포막 신장으로 활성화되는 $K^+$통로의 특성)

  • Lee, Sang-Gook;Jung, Dong-Keun;Suh, Duk-Joon;Park, Soo-Byung
    • The korean journal of orthodontics
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    • v.30 no.2 s.79
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    • pp.197-204
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    • 2000
  • [$K^+$]-selective ion channels were studied in excised inside-out membrane patches from human osteoblast-like cells (G292). Three classes of $K^+$channels were present and could be distinguished on the basis of conductance. Conductances were $270\pm27\;pS,\;113\pm12\;pS,\;48\pm8\;pS$ according to their approximate conductances in symmetrical 140 mM KCl saline at holding potential of -80 mV It was found that the small conductance (48 pS) $K^+$channel activation was dependent on membrane voltage. In current-voltage relationship, small conductance $K^+$channel showed outward rectification, and it was activated by the positive potential inside the membrane. In recordings, single channel currents were activayed by a negative pressure outside the membrane. The membrane pressure increased $P_{open}$ of the $K^+$ channel in a pressure-dependent manner. In the excised-patch clamp recordings, G292 osteoblast-like cells have been shown to contain three types of $K^+$ channels. Only the small conductance (48 pS) $K^+$channel is sensitive to the membrane stretch. These findings suggest that a hyperpolarizing current, mediated in part by this channel, may be associated with early events during the mechanical loading of the osteoblast. In G292 osteoblast-like cells, $K^+$channel is sensitive to membrane tension, and may represent a unique adaptation of the bone cell membrane to mechanical stress.

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RGB Channel Selection Technique for Efficient Image Segmentation (효율적인 이미지 분할을 위한 RGB 채널 선택 기법)

  • 김현종;박영배
    • Journal of KIISE:Software and Applications
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    • v.31 no.10
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    • pp.1332-1344
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    • 2004
  • Upon development of information super-highway and multimedia-related technoiogies in recent years, more efficient technologies to transmit, store and retrieve the multimedia data are required. Among such technologies, firstly, it is common that the semantic-based image retrieval is annotated separately in order to give certain meanings to the image data and the low-level property information that include information about color, texture, and shape Despite the fact that the semantic-based information retrieval has been made by utilizing such vocabulary dictionary as the key words that given, however it brings about a problem that has not yet freed from the limit of the existing keyword-based text information retrieval. The second problem is that it reveals a decreased retrieval performance in the content-based image retrieval system, and is difficult to separate the object from the image that has complex background, and also is difficult to extract an area due to excessive division of those regions. Further, it is difficult to separate the objects from the image that possesses multiple objects in complex scene. To solve the problems, in this paper, I established a content-based retrieval system that can be processed in 5 different steps. The most critical process of those 5 steps is that among RGB images, the one that has the largest and the smallest background are to be extracted. Particularly. I propose the method that extracts the subject as well as the background by using an Image, which has the largest background. Also, to solve the second problem, I propose the method in which multiple objects are separated using RGB channel selection techniques having optimized the excessive division of area by utilizing Watermerge's threshold value with the object separation using the method of RGB channels separation. The tests proved that the methods proposed by me were superior to the existing methods in terms of retrieval performances insomuch as to replace those methods that developed for the purpose of retrieving those complex objects that used to be difficult to retrieve up until now.

Old Service Pipe Cleaning of Polly-pigs Cleaning technique (Polly-pigs를 이용한 노후급수관의 세관에 관한 연구)

  • Lee, Hyun-Dong;Bae, Chul-Ho;Park, Jeong-Hoon;Kim, Gil-Nam
    • Journal of Korean Society on Water Environment
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    • v.18 no.3
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    • pp.303-312
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    • 2002
  • Polly-pigs technique was developed to remove internal rusts and scales from service pipes in the building by using Polly-pigs that were used as various applications in conventional plant pipelines. Results of cleaning experiments on 15mm GSP(Galvanic Steel Pipe) showed that hydraulic cross sectional area was more increased from 3.5% to 15.4% for straight part or elbow parts of several test pieces. Results of optical analysis also showed that rust and scale removed mostly by KDP series(only consisted of Polyurethane) were outside red colored scale ($Fe_2O_3{\cdot}H_2O$), and there was a limitation to the removal of black colored scale($Fe_2O{\cdot}nH_2O$) that was below red colored scale. But it was evaluated that KDPS series coated fine sand with KDP series could remove not only red colored scale but also black colored scale and more increase hydraulic cross sectional areas of 15mm GSP old service pipes from 13.0% to 17.9%. After KDPS series cleaning, hydraulic cross sectional areas of them were recovered from 95.9% to 99.5%. Turning force of Polly-pigs was largely improved by the effect of Helical guide vane(Cleaning v/v) and Rotating wing(Pigs), and the number of pig rotating also more increased sixteen times compared with conventional cleaning system without Helical guide vane and Rotating wing. After KDPC series cleaning of 100mm GSP old service pipes that hydraulic cross sectional areas were 90%, hydraulic cross sectional areas were almost recovered perfectly like new service pipes. Additionally pressure necessary to run Polly-pigs m 100mm GSP was lower and cleaning efficiency also was higher than 15mm GSP cleaning. Therefore it was thought that as the diameter of pipe was more increased, pressure necessary to clean service pipes was more decreased and cleaning efficiency was more increased in Polly-pigs cleaning.