• Title/Summary/Keyword: temperature zone

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Fluid Inclusion and Sulfur Stable Isotope of Buckchang Deposit, Korea (북창광상의 유체포유물 및 황안정동위원소 연구)

  • Chung, Jae-Il;Kim, Seon-Young;Na, Choon-Ki;Lee, In-Sung;Ripley, E.M.
    • Economic and Environmental Geology
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    • v.29 no.6
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    • pp.677-687
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    • 1996
  • The Buckchang deposits which is located in the Ockcheon metamorphic zone, are emplaced along $N20-30^{\circ}E$ trending fissure sets. So it is a sort of fissure-filling ore deposits. The results of mineral paragenetic studies suggest two stages of hydrothermal mineralization; stage I: base-metal sulfides stage, stage II: late base-metal sulfides, electrum and silver-bearing sulfosalts stage. The silver-bearing sulfosalts occured as the Buckchang mine are mainly argentite and, minor of canfieldite, tetrahedrite, etc. Au:Ag ratios of the electrums show a highly limited range of nearly 1:1 in atomic %. The temperature, salinity and pressure of the Buckchang deposits estimated from fluid inclusion and sulfur isotope studies are as follows; stage I: $174{\sim}250^{\circ}C$, 0.35~4.01 NaCl eq. wt.%, 0.40~1.00 Kbar, stage II: $138{\sim}222^{\circ}C$, 1.9~8.4 NaCl eq. wt.%, 0.22~0.53 Kbar. The estimated oxygen and sulfur fugacity during stage I mineralization, based on phase relation of associated minerals, range from $10^{-39.7}{\sim}10^{-44.7}$ atm. and $10^{-13.4}{\sim}10^{-18.1}$ atm., respectively. All these evidences suggest that the Buckchang deposits are polymetallic epithermal ore deposits.

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FE Analysis on the Strength Safety of a Full Containment LNG Storage Tank with Tension Steel Cables (인장강선을 사용한 완전방호식 LNG 저장탱크의 강도안전성에 관한 유한요소해석)

  • Kim, Chung-Kyun;Kim, Tae-Hwan;Kim, Do-Hyun
    • Journal of the Korean Institute of Gas
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    • v.12 no.2
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    • pp.18-24
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    • 2008
  • This paper presents the stress and deformation behaviors of 9% nickel steel inner tank in a full containment LNG storage tank using a FE analysis. For an increased strength safety of an inner tank, the tension cable was fastened around the outside wall of an inner tank, which is known as a weak zone for the hydrostatic pressures, cryogenic temperature loads, and other loadings. Based on the FEM computed results between a conventional inner tank and a inner tank with tension cables around the lower part of the side wall of an inner tank, the redesigned inner tank is more safe than that of the conventional tank without a tension cable. The FEM results recommend $3{\sim}4$ steel tension cables with a diameter of 50mm for an increased strength safety of the inner tank, which may decrease the stress concentration and deformation near the lower part of the side wall. Thus the tension cable around the inner tank may be used as an alternative safety device compared to the stiffener and the top girder structures for the increased LNG storage tank, especially.

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Breeding and cultural characteristics of a newly bred Lentinula edodes strain, 'Bambithyang' (표고 신품종 '밤빛향'의 육성 및 특성)

  • Park, Youngae;Jang, Yeongseon;Ryoo, Rhim;Ka, Kang-Hyeon
    • Journal of Mushroom
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    • v.18 no.2
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    • pp.145-150
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    • 2020
  • A new cultivar, 'Bambithyang', was bred from monokaryotic strains of Sanbaekhyang and SANJO 707ho using the mono-mono hybridization method. Its incubation period was determined to be 100 days and its optimum temperature for fruit body flushing, 11-20℃. The mushrooms had a convex cap (diameter, 69.6 mm; thickness, 15.2 mm) and stipes in their center. The color of their upper sides was chestnut brown; their gills were arranged in a ripple style and had medium density. Their scales were cream-colored and fully distributed; the stipes were cream-colored and cylindrical (thick upper part). They also had cream colored fluffs and sporadic fruiting bodies. Zone lines were present when they were cultivated with mother and father varieties. Their stipe lengths and caps were 9% shorter and 16.9% thicker, respectively, than those of Sanbaekhyang.

A Study on Removal Efficiency of VOCs using Vortex Cyclones (보텍스 사이클론을 이용한 VOCs 제거효율에 관한 연구)

  • Lim, Gye-Gyu
    • Applied Chemistry for Engineering
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    • v.16 no.2
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    • pp.194-199
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    • 2005
  • The principle of vortex cyclone was applied to enhance the treatment efficiency of waste air streams containing particulate matters, phenol, and others. Adsorption, condensation, and/or coagulation could be induced at low temperature zone formed by Joule-Thomson expansion as the pressurized air and pulverized activated carbon were introduced at the tangential direction into the cyclone system applied with the coaxial funnel tube of vortex cyclone. Easily condensible vapors were adsorbed and/or condensed forcibly on coagulated or condensed materials which were formed as cores for coagulation or condensation by themselves or on pulverized activated carbons. These types of coagulation or condensation rates were rapidly promoted by increase in their diameter. The maximum removal efficiency obtained from this experiment for the removal of carbon dioxide and phenol was about 87.3 and 93.8 percent, respectively. Phenol removal efficiency was increased with the relative humidities and enhanced by pulverized activated carbon added. The Joule-Thomson coefficients were increased with the pressure of air injected in the range of the relative humidities between 10% and 50%. It is believed that the moisture, particulate matters, and the pressure of the process air introduced could control the removal efficiency of VOCs.

Bacterial Growth-inhibiting Activity of Amniotic Fluid Against E. coli (양수의 대장균에 대한 세균증식 억제효과)

  • Kim, Soo-Yong;Choi, Myung-Sik;Chang, Woo-Hyun;Cha, Chang-Yong
    • The Journal of the Korean Society for Microbiology
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    • v.22 no.3
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    • pp.233-240
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    • 1987
  • The amniotic fluid provides a medium in which the fetus can readily move, cushions him against possible injury and helps him maintain an even temperature. Besides above mentioned functions, investigators reported that human amniotic fluid contains host-resistance factors which prevent bacteria from producing infectious disease and this activity shows difference among human racial groups or bacterial genera, species and strains. 40 amniotic fluid specimens from Korean women in their second and third trimesters of pregnancy were examined for inhibiting the growth of Escherichia coli. And various factors which might affect bacterial growth inhibiting activity such as pH, initial inoculum size, concentration of amniotic fluid, and heat resistance, were also tested using a strongly inhibitory amniotic fluid specimen. Finally plate diffusion tests were carried out using other strongly inhibitory amniotic fluid. The following results were obtained: 1. Of the 40 fluid samples examined, 18 specimens(45%) had inhibitory activity and samples from women in their second trimester of pregnanancy showed non-inhibitory activity(2 specimens). 2. The pH of the fluids varied between 7.43 and 8.33. There was no correlation between pH and inhibitory activity. 3. No. 19 amniotic fluid showed bacteriostatic activity after 24 hours incubation when an inoculum of $10^2$ organisms per milliliter was used, but non-inhibitory with an inoculum of $10^3$ and $10^4$ bacteria per milliliter. 4. The content of amniotic fluid in culture media influenced E. coli growth. At 90 percent, E. coli was inhibited growth but at 10 percent and 50 percent. 5. Inhibitory activity of No. 19 amniotic fluid was retained after heating to $50^{\circ}C$ for 30 minutes or 100^{\circ}C$ for 30 minutes. 6. Plate diffusion tests with No. 27 amniotic fluid showed that 0.7ml amniotic fluid gave clear zone of growth inhibition around the central well but 0.2ml and 0.1ml amniotic fluids were not.

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Effects of Freezing-Thawing Conditions on Physicochemicnl and Histological Properties of Plaice, Paralichthys olivaceus Muscle (동결-해동 조건이 넙치육의 물리$\cdot$화학적 및 조직학적 변화에 미치는 영향)

  • CHO Young-Je;CHO Min-Sung;LEE Nam-Gul;CHOI Young-Jun;KIM Tae-Jin
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.31 no.4
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    • pp.463-470
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    • 1998
  • To improve muscle quality and prolong freshness of sashimi, the effects of freezing-thawing condition on physicochemical and rheological properties of plaice muscle were investigated. Muscle tested were frozen with quick freezing (liquid nitrogen gas) or slow freezing ($-15^{\circ}C$ air). Transition time of zone of ice crystal formation was within 10 minute for quick freezing and 110 minute for slow freezing. Time required for thawing to $0^{\circ}C$ in muscle temperature by various thawing methods was shortest with $25^{\circ}C$ tap water, followed by $15^{\circ}C$ tap water, $10^{\circ}C$ tap water, $25^{\circ}C$ air, $5^{\circ}C$ tap water and $0^{\circ}C$ cold water. Breaking strength of muscle was higher in quickly frozen sample than in slowly frozen sample. According to sashimi term, changes in breaking strength of muscle did not show any difference in quickly frozen sample, while showed significant difference in slowly frozen sample. The remaining content of ATP was not effected by freezing speed, and ATP content was apt to higher in quickly thawed sample than in slowly thawed sample. IMP was the majority of ATP and it's related compounds of sample after freezing and thawing. Collagen matrix was weakened markedly in slowly frozen sample than in quickly frozen sample.

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Oogenesis and Reproductive Cycle of Glossaulax didyma on the West Coast of Korea (한국 서해산 큰구슬우렁이, Glossaulax didyma의 난자형성과정 및 생식주기)

  • Kim, Dae-Gi;Chung, Ee-Young;Kim, Eun-Jong
    • The Korean Journal of Malacology
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    • v.22 no.1 s.35
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    • pp.13-22
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    • 2006
  • Gonadosomatic index (GSI), oogenesis and reproductive cycle of Glossaulax didyma were investigated by the cytological histological obserbations and morphometric data. Samples were collected monthly from the intertidal zone of Biin Bay, Seocheon, Korea, for one year. Monthly variations in the GSI showed similar patterns with gonadal development. In the early vitellogenic oocyte, the Golgi complex and mitochondria were invovled in the formation of lipid droplet and yolk precursor. In the late vitellogenic oocytes, the rough endoplasmic reticulum and multivesicular bodies were involved in the formation of profeid yolk granules in the cytoplasm. A mature yolk granule was composed of three components: main body (central core), superficial layer, and the limiting membrane. The spawning season was from early June to late August, and the main spawning occurred between July and August when the seawater temperature was above $19^{\circ}C$. The female reproductive cycle can be classified into five successive stages: early active stage (December to February), late active stage (February to March), ripe stage (April to July), spawning stage (June to August), recovery stage (August to November). Fully mature oocytes were approximately $250-270{\mu}m$ in diameter.

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Experimental Study on Reduction of Particulate Matter and Sulfur Dioxide Using Wet Electrostatic Precipitator (습식전기집진기를 활용한 입자상 물질 및 황산화물 저감 성능에 관한 실험적 연구)

  • Kim, Jong-Lib;Oh, Won-Chul;Lee, Won-Ju;Choi, Jae-Hyuk
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.27 no.6
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    • pp.898-904
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    • 2021
  • This experimental study aims to investigate the use of a wet electrostatic precipitator as a post-treatment device to satisfy the strict emission regulations for sulfur oxides and particulate matter (PM). The inlet/outlet of a wet electrostatic precipitator was installed in a funnel using a marine four-stroke diesel engine (STX-MAN B&W) consuming marine heavy fuel oil (HFO) with a sulfur content of about 2.1%. Measurements were then obtained at the outlet of the wet electrostatic precipitator; an optical measuring instrument (OPA-102), and the weight concentration measurement method (Method 5 Isokinetic Train) were used for the PM measurements and the Fourier transform infrared (FT-IR; DX-4000) approach was used for the sulfur oxide measurements. The experimenst were conducted by varying the engine load from 50%, to 75% and 100%; it was noted that the PM reduction efficiency was a high at about 94 to 98% under all load conditions. Additionally, during the process of lowering the exhaust gas temperature in the quenching zone of the wet electrostatic precipitator, the sulfur dioxide (SO2) values reduced because of the cleaning water, and the reduction rate was confirmed to be 55% to 81% depending on the engine load.

A Study on the Rainfall Infiltration Capacity of Soil (A Study on the Mid-Mountain Area of Jeju Island) (강우의 토양 침투 투수성 연구(제주도 중산간 지역을 중심으로))

  • Jeon, Byeong Chu;Lee, Su Gon;Kim, Sung Soo;Kim, Ki Su;Kim, Nam Ju
    • The Journal of Engineering Geology
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    • v.29 no.2
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    • pp.99-112
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    • 2019
  • Rainfall infiltration through the unsaturated zone is influenced by a range of factors including topography, geology, soil, rainfall intensity, temperature and vegetation; the actual infiltration varies largely in time and space. The infiltration capacity of soil is a critical factor in identifying groundwater recharge and leakage of surface water. It may differ depending on soil types and geological features of a particular basin or territory as well as on the usage of the land. This study was conducted in forest and farmland region of the mid-mountain area (EL. 50~300 m) of Jeju Island to test soil infiltration capacity of the area where rainfall contributes to groundwater. Results were analyzed using the four soil group classification methods presented by Jeong et al. (1995) and NAS (2007) to discover that the method offered by NAS (2007) is more reliable in the mid-mountain area of Jeju Island. The study compares and reviews the existing classification methods using the results of infiltration capacity tests executed on different soil groups throughout the whole region of the Jeju mid-mountain area. It is expected that this work will serve as a guideline for evaluating surface water recharge and hydraulic characteristics of Jeju Island.

Design Optimization of Multi-element Airfoil Shapes to Minimize Ice Accretion (결빙 증식 최소화를 위한 다중 익형 형상 최적설계)

  • Kang, Min-Je;Lee, Hyeokjin;Jo, Hyeonseung;Myong, Rho-Shin;Lee, Hakjin
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.50 no.7
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    • pp.445-454
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    • 2022
  • Ice accretion on the aircraft components, such as wings, fuselage, and empennage, can occur when the aircraft encounters a cloud zone with high humidity and low temperature. The prevention of ice accretion is important because it causes a decrease in the aerodynamic performance and flight stability, thus leading to fatal safety problems. In this study, a shape design optimization of a multi-element airfoil is performed to minimize the amount of ice accretion on the high-lift device including leading-edge slat, main element, and trailing-edge flap. The design optimization framework proposed in this paper consists of four major parts: air flow, droplet impingement and ice accretion simulations and gradient-free optimization algorithm. Reynolds-averaged Navier-Stokes (RANS) simulation is used to predict the aerodynamic performance and flow field around the multi-element airfoil at the angle of attack 8°. Droplet impingement and ice accretion simulations are conducted using the multi-physics computational analysis tool. The objective function is to minimize the total mass of ice accretion and the design variables are the deflection angle, gap, and overhang of the flap and slat. Kriging surrogate model is used to construct the response surface, providing rapid approximations of time-consuming function evaluation, and genetic algorithm is employed to find the optimal solution. As a result of optimization, the total mass of ice accretion on the optimized multielement airfoil is reduced by about 8% compared to the baseline configuration.