• Title/Summary/Keyword: Saturated temperature

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An Experimental Study on the Cooling Tower of Plume Prevention and Performance Improvements (냉각탑 백연방지의 성능 향상에 관한 실험적 연구)

  • JEONG, SOON YOUNG;LEE, BYEONG CHEON;KIM, SUNG
    • Journal of Hydrogen and New Energy
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    • v.30 no.6
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    • pp.578-584
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    • 2019
  • The occurrence of white plume in the cooling tower is phenomenon that the steam in the air through the cooling tower fan is condensed again by the cold ambient air to become saturated moist air. Accordingly, this can cause many problems like spoiling landscape around the cooling tower, odor of ambient air, falling accident by frozenness in the winter, and traffic accident, etc. This study was to install the heat exchanger in the inside of the cooling tower in order to prevent the white plume phenomenon in the cooling tower without affecting the performance of cooling tower. In addition, this study was to discharge the part of cooling water into the atmosphere through the recirculation of heat exchanger after creating dry air by heating the saturated moist air to the dew point temperature. At that time, this study was to conduct the experimental study in order to secure the optimal design data to prevent the white plume in the cooling tower because it checked the dry·moist temperature and relative humidity in the inside·outside of cooling tower on the moist air, and evaluated the performance of the heat exchanger.

Analysis of User Preference about the Color Rendering Index, Correlated Color Temperature and Illuminance of LED Lighting in Merchandising Spaces (상업공간에서의 사용자 선호 LED 조명 연색지수와 상관색온도, 조도의 분석)

  • Lee, Su-Jung;Yoon, Hea-Kyung
    • Journal of the Architectural Institute of Korea Planning & Design
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    • v.35 no.1
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    • pp.99-106
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    • 2019
  • This study aims to recommend the proper Color rendering index (CRI), the Correlated Color Temperature (CCT), and illuminance levels of Light-Emitting Diode (LED) lighting based on the analysis of the criteria of the current CRI, the CCT, and illuminance levels in merchandising spaces with LED lighting conditions. It would be a basic material to apply in line with user preference for LED merchandising lighting. To this end, it examines relevant literature review on the experiments designed to test whether lighting characteristics affect brightness perception, color appearance, and pleasantness. Highly saturated colors appear brighter than low saturated colors. Two lighting applications - grocery and clothing shop - were created in elaborating the effect of LED lighting characteristics of CRI on color appearance and the CCT and illuminance on pleasantness. The findings show that the criteria of CIE Ra<80 are appropriate to provide better color appearance of illuminated products in terms of LED lighting that can enhance color saturation, particularly for the red color. Furthermore, 2700 K and less than 500 lux for grocery, 4000 K and more than 500 lux for clothing shop are found to be the proper the CCT and illuminance levels respectively to bring better preference under LED lighting.

External Condensation Heat Transfer Coefficients of R22 Alternative Refrigerants and R134a According to the Saturated Vapor Temperature Change on an Enhanced Tube (열전달 촉진관에서 R22 대체냉매 및 R134a의 포화증기 온도변화에 따른 외부 응축 열전달계수에 관한 연구)

  • Yoo Gil-Sang;Hwang Ji-Hwan;Park Ki-Jung;Jung Dongsoo
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.17 no.11
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    • pp.981-989
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    • 2005
  • In this study, external condensation heat transfer coefficients (HTCs) are measured on a low fin tube and Turbo-C tubes at the saturated vapor temperature of $30^{\circ}C$, $39^{\circ}C$, and $50^{\circ}C$ for R22, R410A, R407C and R134a with the wall subcooled at $3{\~}8^{\circ}C$. The HTCs of all refrigerants decreased as increasing the saturation temperature from $30^{\circ}C$ to $50^{\circ}C$. This trend is due to better thermodynamic properties of the liquid phase at low temperature Beatty and Katz's prediction yielded a $20.0\%$ deviation for the low fin tube data. The heat transfer enhancement factors for the 26 fpi low fin tube and Turbo-C tubes are 4.0${\~}$5.5 and 3.0${\~}$8.1 respectively for the refrigerants tested. Finally the performance of Turbo-C tube is better than that of the low fin tube.

Evaluation of Microstructure and Ductile-Brittle Transition Temperature in Thermally aged 2.25Cr-1Mo Steel by Electrical Resistivity Measurement (전기비저항을 이용한 2.25Cr-1Mo 강 열화재의 미세조직 및 연성-취성천이온도 평가)

  • Byeon, Jai-Won;Kwun, S.I.
    • Journal of the Korean Society for Nondestructive Testing
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    • v.22 no.3
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    • pp.284-291
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    • 2002
  • An attempt was made to evaluate the degree of aging degradation in thermally aged 2.25Cr-1Mo steel by electrical resistivity measurement. Artificial aging was performed to simulate the microstructural degradation in 2.25Cr-1Mo steel arising from long time exposure at $540^{\circ}C$. Microstructural parameter (amount of solid solution element), mechanical property (ductile-brittle transition temperature) and electrical resistivity were measured to investigate the mutual relationship among these parameters. Depletion of solid solution element(Mo and Cr) in matrix was detected after aging. The ductile-brittle transition temperature(DBTT) increased rapidly in the initial stage of aging and then saturated afterward. On the other hand, the electrical resistivity decreased rapidly in the beginning and then saturated in the later stage of aging.

Changes in Lipids- and Fatty Acids Compositions in Response to Growth Temperature of Streptomyces viridochromogenes (배양온도 변화에 따른 Streptomyces viridochromogenes의 지질과 지방산 조성변화)

  • 김재헌;김우상
    • Korean Journal of Microbiology
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    • v.39 no.3
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    • pp.155-160
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    • 2003
  • The wild type and two morphological variants of Streptomyces viridochromogenes were studied for their lipidand fatty acid compositions at different incubation temperatures. It showed that a decrease in triacylglycerol content was closely linked to the aerial mycelium formation. Phospholipids showed no characteristic changes, except that the contents of phosphatidylethanolamine were clearly high for aerial mycelium deficient strain BR2 grown at $20^{\circ}C$. The strain BR2 also presented unidentified aminolipids with various $R_{f}$ values. Among the aminolipids, ornithinolipid increased gradually during the cultivation for all strains. The changes in fatty acid compositions showed a temperature dependency that the proportion of unsaturated acids decreased as the growth temperature increased. The proportion of straight chain saturated fatty acids decreased as the aerial mycelium developed, and it was most evident for the mutant strain M13 with more extensive aerial mycelium. The mutant strain BR2 presented significantly higher level of iso branched odd numbered saturated fatty acids.

Conditions of Desalination with Reduced Pressure Evaporation Device (감압증발장치와 해수담수화의 조건)

  • Ji, Ho;Yun, Sung Yeol;Lee, Seung Won;Moon, Deok Soo;Lee, Ho Saeng;Kim, Hyeon Ju
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.17 no.1
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    • pp.8-12
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    • 2014
  • Reduced pressure evaporation applies the principle of lowering water's boiling point by reducing the pressure. It uses the relation between temperature and pressure to reduce energy consumption needed for elevating temperature. As the result, the highest evaporation was observed at $80^{\circ}C$ and -40 cmHg applying saturated vapor pressure depending on different seawater temperature. It was found that the higher concentration in the factor test experiment depending on seawater concentration induced the higher evaporation. Also, in the factor test experiment, the amount of evaporation increased as the pressure decreased. It is concluded that the most important factor of evaporation was concentration, the second important factor was temperature, and the least important factor was pressure. Through this experiment, optimized conditions of desalination with reduced pressure evaporation device were verified.

Stain removal on ivory using cyclododecane as a hydrophobic sealing agent

  • Lee, Hyun-Sook
    • KOMUNHWA
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    • no.66
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    • pp.87-112
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    • 2005
  • Stain removal on ivory has been, for a long time, considered an undesirable treatment in conservation field because ivory is hygroscopic and anisotropic, having different physical properties in different directions. Cyclododecane, which sublimes at room temperature, has been investigated for its use in conservation field since 1995, as a reversible temporary consolidant, sealing agent or coating, water repellent, and barrier layer. This research aims to remove stains on ivory, temporarily protecting the none-stained area or painted area from methanol, acetone or the aqueous cleaning system using cyclododecane as a hydrophobic sealing agent. This research also aims to obtain information regarding whether cyclododecane can be safely and effectively used on archaeological wet ivory. Melted cyclododecane and saturated solutions of cyclododecane in mineral spirits, and hexanes were applied to ivory samples. Application methods, working properties of cyclododecane on ivory, and effect of cyclododecane coating on moisture content of wet ivory were evaluated. The sealing layer formed by molten cyclododecane or by saturated cyclododecane solution in hexane or saturated cyclododecane solution in mineral spirits did not form a secure contact with the surface of the highly polished ivory. The sealing formed with two different layers, in which saturated cyclododecane solution in hexane was applied initially and then molten cyclododecane was applied over the first layer, was found to securely protect the painted area. When the wet samples were kept in 100% RH environments for a month, active mold growths were observed except in the samples sealed with molten cyclododecane. In conclusion, cyclododecane was an efficient hydrophobic sealing agent to protect painting area while cleaning stains on ivory. It also prevented mold growing on wet ivory and wet bone. Evenness of cyclododecane film on ivory will be determined in UV light. Analytical techniques will include visual observation, polarized light microscopy, Scanning Electron Microscope, and Gas Chromatography.

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Reduction of Saturated Fatty Acid Methyl Esters of Biodiesel Produced from Beef Tallow by Acetone Fractionation (우지로부터 합성된 바이오 디젤의 포화도 감소를 위한 용매 분별 연구)

  • Zhang, Hua;Shin, Jung-Ah;Lee, Ki-Teak
    • Journal of the Korean Applied Science and Technology
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    • v.28 no.4
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    • pp.472-481
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    • 2011
  • It is known that the content of saturated fatty acids methyl ester (SFAME) affect the pour point of biodiesel at low temperature. In this study, biodiesel (BD) was produced from beef tallow (TAL) by alkali catalyst. To reduce the saturation in BD, acetone fractionation was applied. Besides, TAL was also solvent-fractionated to reduce the saturated fatty acid (SFA) content for further producing BD. With acetone, TAL or TAL methyl ester (5:1 v/w) were fractionated at 10, 0, -10, and $-15^{\circ}C$, respectively. At $-10^{\circ}C$, 17.35% of SFA was observed in fractionated TAL (liquid part, -10TAL) when 5:1 solvent ratio was used for 24 hr. Under the same condition, fractionated BD (liquid part, -10BD) showed SFA (33.14%) with 78wt % yield. Also, fractionation of BD with different concentration of crystallizer 209 (0.1, 0.5, and 1%) along with different time (2, 6, 12, and 24 hr.) was observed. The best condition for reducing the SFA was 0.5% of crystallizer 209 addition for 12 hr of fractionation time at $-10^{\circ}C$, in which 30.14% of SFA content was observed in BD (liquid part). Among different crystallizer, ps 66 showed the least content of SFA content (23.28%) in BD after fractionation ($-10^{\circ}C$ and 24 hr) with 0.5wt% addition.

A Study on the Saturation of Grain Size in Pb(Zr, Ti)$O_3$ Thin Films (Pb(Zr, Ti)$O_3$ 박막에서 결정립 크기 포화 현상에 관한 연구)

  • 이장식;김찬수;주승기
    • Journal of the Korean Ceramic Society
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    • v.37 no.6
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    • pp.530-536
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    • 2000
  • During the grain growth of the PZT thin films by selective nucleation method using PZT seed, it was found that the grain size was saturated with the annealing temperature. The saturation of grain size was analyzed by the interfacial energy which appeared during the crystallization. The factors affecting the saturation of grain size were found to be the interfacial energy between perovskite phase and pyrochlore phase, and PZT thin film and the bottom Pt electrode. When the ion damage was introduced to the grain-size saturated PZT thin films, further lateral growth was observed. Pt bottom electrode thickness was changed to control the interfacial energy between the PZT thin film and the Pt bottom electrode. When Pt thickness was increased, the grain size was also increased, because the lattice parameter of Pt films was increased with the thickness of the Pt films. The incubation time of nucleation was increased with the amount of the ion damage on the Pt films.

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Experimental Research on the Comparison of Gravity Moisture Content and Relative Moisture Content in Calculating the Quantitative Percentage of Moisture Content (중량함수율 및 상대함수율 비교에 따른 정량적인 함수율 산정에 대한 실험적 연구)

  • Byun, Yong-Hyun;Ryu, Dong-Woo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2016.05a
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    • pp.134-135
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    • 2016
  • This study aims to compare relative moisture content and gravity moisture content in calculating the rational percentage of moisture content. High-strength concrete, which is made of blast-furnace slag and silica fume, was used as the compound for this study, and the specimens were made into a saturated condition through the vacuum suction. According to the results of this study, all specimens were completely dried when they were under the temperature of 105℃ for more than 31 days. They were fully saturated after 72 hours through vacuum suction. In addition, relative moisture content responded more sensitively to moisture content than gravity moisture content did, so it can be concluded that relative moisture content is better in calculating the rational percentage of moisture content.

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