• Title/Summary/Keyword: a confined area

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The Optimal Design of Explosion Prevention for LPG Storage Tank (폭발방지를 고려한 LPG 저장탱크 최적설계)

  • Leem, Sa-Hwan;Huh, Yong-Jeong;Son, Seok-Woo;Lim, Jae-Ki
    • Proceedings of the KAIS Fall Conference
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    • 2010.05b
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    • pp.949-952
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    • 2010
  • The utilization of LPG(Liquefied Petroleum Gas) is increasing as an environmental-friendly fuel in all countries making green growth new paradigm, and use of gas is spread fast as motor fuels to decrease air pollution. Loss of lives by explosion and fire is happening every year as gas use increases, and gas accident in large scale storage property is causing serious problems socially. To minimize this problem, underground containment type storage tank is being presented as an alternative recently. In this study, to minimize explosion occurrence in underground containment type storage tank, the suitable storage tank is designed to consider explosion prevention that makes exposure surface area minimize in confined contents volume and flame to construct storage tank by the most suitable condition in the underground containment room. As a result of the design of storage tank having the most suitable condition by this research, underground containment space was minimized on diameter 3m, length 4.83m in 20 tons storage tank and its safety was improved as exposure surface area in flame decreased by 89.4%, compared with the existent storage tank.

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Finite Element Analysis of Inelastic Behavior of SRC Composite Piers (SRC 합성교각의 비탄성거동에 대한 유한요소해석)

  • Shim, Chang-Su;Han, Jung-Hoon;Park, Chang-Kyu;Chung, Young-Soo
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2006.03a
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    • pp.269-275
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    • 2006
  • In the design of bridge piers in seismic area, the ductility requirement is one of the most important design criteria. In order to enhance the seismic performance of RC columns, it is necessary to make the ductility of columns larger by covering RC columns with steel tubes or confining RC columns by arranging transverse reinforcement such as hoop ties closely. Concrete encased composite columns can be utilized for bridge piers especially in seismic area. In this paper, finite element analyses are performed to study the nonlinear behavior of concrete encased composite columns with single core steel or multiple steel elements under static and quasi-static loads. The cross-sections of these specimens ate composed of concrete-encased H-shaped structural steel columns and a concrete-encased circular tube with partial in-filled concrete. Test parameters were the amount of the transverse reinforcement, encased steel member, and loading axis. Through the comparison between FE analyses and test results, adequate material models for confined concrete and unconfined concrete ate investigated. After getting the proper analysis models for composite columns, several parameters are considered to suggest design considerations on the details of composite piers.

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Optimal Welding Condition for the Inclined and Skewed Fillet Joints ill the Curved Block of a Ship (I) (선박 골블록의 경사 필렛 이음부의 적정 용접조건 (I))

  • PARK JU-YONG
    • Journal of Ocean Engineering and Technology
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    • v.18 no.6 s.61
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    • pp.79-83
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    • 2004
  • The curved blocks which compose the bow and stem of a ship contain many skewed joints that are inclined horizontally and vertically. Most of these joints have a large fitness error and are continuously changing their form and are not easily accessible. The welding position and parameter values should be appropriately set in correspondence to the shape and the inclination of the joints. The welding parameters such as current, voltage, travel speed, and melting rate, are related to each other and their values must be in a specific limited range for the sound welding. These correlations and the ranges are dependent up on the kind and size of wire, shielding gas, joint shape and fitness. To determine these relationships, extensive welding experiments were performed. The experimental data were processed using several information processing technologies. The regression method was used to determine the relationship between current voltage, and deposition rate. When a joint is inclined, the weld bead should be confined to a the limited size, inorder to avoid undercut as well as overlap due to flowing down of molten metal by gravity. The dependency of the limited weld size which is defined as the critical deposited area on various factors such as the horizontally and vertically inclined angle of the joint, skewed angle of the joint, up or down welding direction and weaving was investigated through a number of welding experiments. On the basis of this result, an ANN system was developed to estimate the critical deposited area. The ANN system consists of a 4 layer structure and uses an error back propagation learning algorithm. The estimated values of the ANN were validated using experimental values.

Invasion potential of Kappaphycus alvarezii on corals at Kurusadai Island, Gulf of Mannar, India

  • Mandal, Subir Kumar;Mantri, Vaibhav A.;Haldar, Soumya;Eswaran, Karuppanan;Ganesan, Meenakshisundaram
    • ALGAE
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    • v.25 no.4
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    • pp.205-216
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    • 2010
  • The marine red alga Kappaphycus alvarezii is a major source of $\kappa$-carrageenan. It has been introduced in 20 countries including India. Recently, several reports have expressed concerns about Kappaphycus invasion on Acropora corals at Kurusadai Island in the Gulf of Mannar, India, which is part of a marine bioreserve. To understand the extent of the Kappaphycus invasion, 27 randomly selected locations around Kurusadai Island and the mainland coast were surveyed during May-August 2008 and July 2009. Our rigorous sampling revealed that K. alvarezii was confined to two different patches of 105 m $\times$ 55 m and 8 m $\times$ 9 m located at the southeastern part of Kurusadai Island. The actual extent of the K. alvarezii canopy coverage was 76.7 $m^2$, accounting for less than 0.0035% of the total coral reef area. The daily growth rate of the K. alvarezii at Kurusadai was 0.7%. K. alvarezii was not observed in the coral reef area of the adjoining Pullivasal and Poomarichan Islands or the Palk Bay area cultivation sites. The lack of functional reproductive cycle, low spore viability, and the absence of microscopic phases in the life cycle of this alga coupled with the abundance presence of herbivores may restrict the further spread of this alga, so its invasive potential at Kurusadai Island is considered remote.

A Study of the Cause-of-Death reported on Official Death Registry in a Rural Area (일부 농촌지역 사망신고자료에 기재된 사인에 관한 연구 -사망신고사인과 조사사인의 비교-)

  • Nam, Hae-Sung;Park, Kyeong-Soo;Sun, Byeong-Hwan;Shin, Jun-Ho;Sohn, Seok-Joon;Choi, Jin-Su;Kim, Byong-Woo
    • Journal of Preventive Medicine and Public Health
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    • v.29 no.2 s.53
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    • pp.227-238
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    • 1996
  • This study was conducted to evaluate the accuracy of the official death registry in rural area. The base data used for the study was 379 deaths registered during the period of 1993 and 1994 in 4 rural townships of Chonnam province. The interview survey for cause-of-death was performed on the next of kin and/or neighbor. Additional medical informations were collected from hospitals and medical insurance associations for the purpose of verification. The underlying cause-of-death of 278 cases presumed by the survey was compared to the cause on official death registry. There was a prominent disagreement of cause-of-death between the survey data and the registry data(agreement rate: $38.9\sim44.6%$, according to disease classification method). These results may be caused by extremely low rates of physicians' certification, which were mostly confined to the poisoning and injury. Symptoms, signs, and ill defined conditions on death registry could be classified into circulatory disease(32.3%), neoplasm(21.2%), digestive disease(7.1%), injury and poisoning(7.1%) and so on. These results suggest that careful attention and verification be required on utilization of death registry data in rural area.

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Analysis of the thermal management of a high power LED package with a heat pipe

  • Kim, Jong-Soo;Kim, Eun-Pil
    • Journal of Advanced Marine Engineering and Technology
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    • v.40 no.2
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    • pp.96-101
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    • 2016
  • The thermal management of high-power LED components in an assembly structure is crucial for the stable operation and proper luminous function. This study employs numerical tools to determine the optimum thermal design in LEDs with a heat sink consisting of a crevice-type vapor-chamber heat pipe. The effects of the MCPCB are investigated in terms of the substrate thicknesses on which the LEDs are mounted. Further, different placement configurations in a system module are considered. This study found that for a confined area, a power of 40 W/LED is applicable to a high-power package. Furthermore, the thermal conductivity of dielectric layer materials should ideally be greater than 0.9 W/m.K. The temperature conditions of the vapor chamber in a heat pipe greatly affect the thermal performance of the system. At an offset distance of 9.0 mm and a $2^{\circ}C$ increase in the temperature of the heat pipe, the resulting maximum temperature increase is approximately $1.9^{\circ}C$ for each heat dissipation temperature. Finally, at a thermal conductivity of 0.3 W/m.K, it was found that the total thermal resistance changes dramatically. Above 1.2 W/m.K, the resistance change reduces exponentially.

Printing Technologies for the Gate and Source/Drain Electrodes of OTFTs

  • Lee, Myung-Won;Lee, Mi-Young;Song, Chung-Kun
    • Journal of Information Display
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    • v.10 no.3
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    • pp.131-136
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    • 2009
  • This is a report on the fabrication of a flexible OTFT backplane for electrophoretic display (EPD) using a printing technology. A practical printing technology for a polycarbonate substrate was developed by combining the conventional screen and inkjet printing technologies with the wet etching and oxygen plasma processes. For the gate electrode, the screen printing technology with Ag ink was developed to define the minimum line width of ${\sim}5{\mu}m$ and the thickness of ${\sim}70nm$ with the resistivity of ${\sim}10^{-6}{\Omega}{\cdot}cm$, which are suitable for displays with SVGA resolution. For the source and drain (S/D) electrodes, PEDOT:PSS, whose conductivity was drastically enhanced to 450 S/cm by adding 10 wt% glycerol, was adopted. In addition, the modified PEDOT:PSS could be neatly confined in the specific S/D electrode area that had been pretreated with oxygen. The OTFTs that made use of the developed printing technology produced a mobility of ${\sim}0.13cm^2/Vs.ec$ and an on/off current ratio of ${\sim}10^6$, which are comparable to those using thermally evaporated Au for the S/D electrode.

Variable-focus Liquid Lens Based on a Laterally-integrated Thermopneumatic Actuator

  • Lee, June Kyoo;Park, Kyung-Woo;Lim, Geunbae;Kim, Hak-Rin;Kong, Seong Ho
    • Journal of the Optical Society of Korea
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    • v.16 no.1
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    • pp.22-28
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    • 2012
  • We report a focal-length tunable liquid lens based on thermopneumatically driven fluidic pressure. The fluidic pressure is generated by deformation of an elastomeric diaphragm induced by thermopneumaticity from a laterally integrated microheater sealed within an air chamber. The pressure is transmitted by a confined liquid to a lens diaphragm through an internal fluid channel. The liquid filling under the lens diaphragm functions as a liquid lens for dynamic focusing with properties depending on the curvature of the deformed diaphragm. The diaphragm area of the air chamber is designed five times larger than that of the lens cavity to yield high focal-length tunability by amplified deflection of the lens diaphragm. With our method, we achieved excellent focal-length tunability from infinity (without an input current) to 4 mm (with an input current of 12 mA) with a lens aperture diameter of 2 mm.

TWO CASES REPORT OF MAXILLARY SINUS ASPERGILLOSIS (상악동에 발생한 국균증의 치험2례)

  • Kim, Soo-Min;Yeo, Hwan-Ho;Kim, Young-Kyun;Kim, Su-Gwan;Cho, Jeo-O
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.18 no.4
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    • pp.726-733
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    • 1996
  • Aspergillosis of the maxillary sinus was rare disease, but it was increasing tendency with overuse antibiotics, streoid hormones, and anticanncerous agents. The clinical features and X-ray findings are similar to chronic suppurative paranasal sinusitis. Aspergillosis of the maxillary siuses may occur as a chronic diseae in an otherwise healthy person. This infection is usually confined to a single paranasal sinus, the maxillary antrum, though it can involve the orbit and may initiate with findings of proptosis and decreased vision. The disease is characterized by a wide range of initial symptoms, and should be considered as a possible diagnosis in sinusitis refractory to antibiotics and antral lavage. The choice of treatment of this disease is radical surgery and adjunctive systemic antifungal therapy. We experienced a case of right maxillary sinus aspergillosis in a 34 years old male who has dull pain on Rt. zygoma area, and a case of left maxillary sinus aspergillosis in a 30 years old male who had been suffered from nasal stiffness and frontal headache for 3-4 years. We reported two cases with review of literature.

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Immature thymocyte antigen, JL1, as a possible immunodiagnostic and immunotherapeutic target for leukemia

  • Shin, Young Kee;Choi, Eun Young;Kim, Seok Hyung;Park, Seong Hoe
    • IMMUNE NETWORK
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    • v.1 no.1
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    • pp.1-6
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    • 2001
  • The identification of tumor-specific antigens has represented a critical milestone in cancer diagnosis and therapy. Clinical research in this area for leukemia has also been driven over the past few decades by the hope that surface antigens with restricted tissue expression would be identified. Disappointingly, only a small number of the leukemic antigens identified to date, meet sufficient criteria to be considered viable immunophenotypic markers. In this paper, we nominate anti-JL1 monoclonal antibody as an immunodiagnostic and immunotherapeutic candidate for leukemia. The JL1 molecule appears to be a novel cell surface antigen, which is strictly confined to a subpopulation of limited stages during the hematopoietic differentiation process. Despite the restricted distribution of the JL1 antigen in normal tissues and cells, anti-JL1 monoclonal antibody specifically recognizes various types of leukemia, irrespective of immunophenotypes. On the basis of these findings, we propose JL1 antigen as a tumor-specific marker, which shows promise as a candidate molecule for diagnosis and immunotherapy in leukemia, and one that spares normal bone marrow stem cells.

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