• Title/Summary/Keyword: Viscosity Effect

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Effect of Germanium-132 on the Growth of Lactic Acid Bacteria (젖산균의 성장에 미치는 Ge-132의 영향)

  • Park, Seok-Kyu;Lee, Sang-Won;Takafumi Kasumi
    • Food Science and Preservation
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    • v.6 no.4
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    • pp.506-513
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    • 1999
  • The growth of lactic acid bacteria was investigated in liquid broth medium containing organic germanium compound(Ge-132, carboxyethylgermanium sesquioxide) in the range of 0.01 to 10mg/ml. Most of all lactic acid bacteria tested were tolerant and could grow better to the high Ge-132 concentration. However, the growth of Leuconostoc mesenteroides and Pediococcus pentosaceus were inhibited in the presence of 10mg/m1 Ge-132. Among 22 strains tested, lactic acid bacteria that were grown to a high degree(about 2 times) by addition of Ge-132 (10mg/ml)were Lactococcus lactis, Lc. cremoris, Lc. diacetilactis, Enterococcus faecium and Streptococcus faecalis. The growth of these strains were markedly accelerated in the culture medium supplemented with 1.omg/ml Ge-132 The optimal concentration of glucose for growth of Lc. lactic was found to be high in medium containing Ge-132 as compared with the case of control. During cultivation viscosity in culture broths of Lc. lactis and Lc. cremoris was rapidly elevated by adding Ge-132 to medium containing high concentration of glucose, and then decreased after incubation of long time. However, in the cultivation of Lc. diacetilactis, E, faecium and S. faecalis, viscosity of culture broths was not increased, even though Ge-132 was shown to be an effective stimulant of growth.

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THD Lubrication Analysis of a Surface-Textured Parallel Thrust Bearing with Rectangular Grooves: Part 1 - Effect of Film-Temperature Boundary Condition (사각형 그루브로 Surface Texturing한 평행 스러스트 베어링의 열유체윤활 해석: 제1보 - 유막온도경계조건의 영향)

  • Park, TaeJo;Kang, JeongGuk
    • Tribology and Lubricants
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    • v.38 no.6
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    • pp.267-273
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    • 2022
  • Surface texturing is the latest technology for processing grooves or dimples on the friction surface of a machine. When appropriately applied, it can reduce friction and significantly increase durability. Despite many studies over the past 20 years, most are isothermal (ISO) analyses in which the viscosity of the lubricant is constant. In practice, the viscosity changes significantly owing to the heat generated by the viscous shear of the lubricant and film-temperature boundary condition (FTBC). Although many thermohydrodynamic (THD) analyses have been performed on various sliding bearings, only few results for surface-textured bearings have been reported. This study investigates the effects of the FTBC and groove number on the THD lubrication characteristics of a surface-textured parallel thrust bearing with multiple rectangular grooves. The continuity, Navier-Stokes, and energy equations with temperature-viscosity-density relations are numerically analyzed using a commercial computational fluid dynamics code, FLUENT. The results show the pressure and temperature distributions, variations of load-carrying capacity (LCC), and friction force with four FTBCs. The FTBCs greatly influence the lubrication characteristics of surface-textured parallel thrust bearings. A groove number that maximizes the LCC exists, which depends on the FTBC. ISO analysis overestimates the LCC but underestimates friction reduction. Additional analysis of various temperature boundary conditions is required for practical applications.

Experimental Studies on the Efficiency of Insamyunpye-Hwan (인삼윤폐환(人蔘潤肺丸)의 효능(效能)에 관(關)한 실험적(實驗的) 연구(硏究))

  • Rhee, Hyung-Koo
    • Korean Journal of Oriental Medicine
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    • v.2 no.1
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    • pp.314-326
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    • 1996
  • Experimental studies were done to research the clinical effect of Insamyunpye-H wan on viscousity of mucin solution, pulmonary thromboembolism, oxygen consumption in $O_3$-exposed and Lung TBA in rats and mice. The result was obtained as follows : 1. In the effect of viscosity sampled from mucin, Insamyunpye-Hwan was revealed to have a significant effect of decrease in the rate of viscousity (p<0.01). 2. In the effect of sodium aracdonic acid induced pulmonary thromboembolism, I samyunpye-Hwan was revealed to have an effect of increasing the number of survival, but were not significant 3. In the effect of ADP induced pulmonary thrornboembolism, Insamyunpye-Hw an was revealed to have an effect of increasing the number of survival, but were not significant 4. In the effect of oxygen cansumption values in rats exposed-$O_3$, Insarnyunpye-Hwan was revealed to have a significant effect (p<0.05). 5. In the effect of the lung TBA values in rats exposed-$O_3$, Isamyunpye-Hwan was revealed to have a significant effect (p<0.05). In connection with the results of the studies, Insamyunpye-Hwan is concluded to be effective on the treatment of cough and lung and respiratory organ damages.

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A Effect of Fuel Properties on Spray Structure for Dual Orifice Fuel Injector (연료의 물성치 변화가 이중 오리피스 연료 노즐의 분무 구조에 미치는 영향에 관한 연구)

  • Lee, Dong-Hun;Choi, Seong-Man;Park, Jeong-Bae
    • 한국연소학회:학술대회논문집
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    • 2003.05a
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    • pp.179-188
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    • 2003
  • The spray characteristics of dual orifice injector were investigated under two different fuels through measurement of SMD, number density and volume flux by using PDPA system. In this experiment, we found out that the droplet size and spray structure are strongly depend on fuel density and viscosity.

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Influence of Carrageenan and Pectin addition on the rheological properties of Omiia Extract Jelly (Carrageenan과 Pectin을 첨가한 오미자 젤리에 관한 연구)

  • 심영자;백재은;주나미;전희정
    • Korean journal of food and cookery science
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    • v.11 no.5
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    • pp.443-445
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    • 1995
  • This study attempted to examine the effect on sensory characteristcs and physiochemical properties of Omija jelly in various volume of adding carrageenan and pectin. The viscosity and the turbidity were decreased according to the increase concentration Omija jelly with pectin. The sensory evaluation of Omija jelly was the best with the ratio 0.5% carrageenan.

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Dynamic Characteristics of a Beam Sujected to an Axial Force and a Force of Time Dependent Frequency - Effect of Solid Viscosity - (시간종속적 하중을 받는 축하중을 받을 때의 동특성 - 고체점성 고찰 -)

  • 정태진;박영조
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.10 no.4
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    • pp.456-462
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    • 1986
  • 본 논문은 Voigt형의 고체점성을 갖는 단순기지보에 외부기진력이 sin(1/2 at$^{2}$+1/3bt$^{3}$)인 꼴로 작용할 때에 축하중 및 각속도의 변화에 따른 동적 처짐 효과를 고찰하였다.

Analysis of Cylindrical Hydrostatic Bearing (진원형 정수압 베어링의 해석)

  • 문호지;한동철
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 1989.11a
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    • pp.94-99
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    • 1989
  • This paper analyzes file stiffness, damping coefficient, friction force and flow coefficient of externally pressurized oil journal beating, including the effect of journal rotation according to the Sommerfeld number. This paper assumed that the oil in the whole pocket has constant pressure, and that the oil in the whole bearing region has constant viscosity, temperature and density. Reynolds equation is derived from Nuvier - Stokes equation and continuity equation. And solved bearing pressure by ADI method for whole bearing region and fitted with out flow rate of pocket region. The model for numerical simulation is hydro - static oil journal bearing for high-speed, high-accuracy lathe spindle.

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Influence of Carrageenan and Pectin addition on the rheological properties of Omija Extract Jelly (Carrageenan과 Pectin을 첨가한 오미자 젤리에 관한 연구)

  • 심영자;백재은;주나미;전희정
    • Korean journal of food and cookery science
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    • v.11 no.4
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    • pp.362-364
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    • 1995
  • This study attempted to examine the effect on sensory characteristics$.$and physiochemical propertics of Omija jelly in various volume of adding carrageenan and pectin. The viscosity and the turbidity were decreased according to the increase concentration Omija jelly with pectin. The sensory evaluation of Omija jelly was the best with the ratio 0.5% carrageenan.

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Control of Hydrocracking Temperature in Ebulated Recycle Reactor (유동화 재순환 반응기에서 석유의 수소첨가 반응시 이탈된 온도제어)

  • 이창우;홍영호;함영민
    • Journal of the Korean Society of Safety
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    • v.13 no.2
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    • pp.76-87
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    • 1998
  • This study was carried out to investigate the effect of on temperature control from actuating method, recycling ratio and the position (top, middle and bottom) of set and controlled temperature within the reactor in adiabatic ebullated recycling condition, when the disturbance was occurred. Estimation of the solution were performed numerically using the finite difference method. It was assumed that the reaction is in constant with heat of reaction and the physical properties(density, heat capacity and viscosity, etc) of the reactants are same condition within the reactor.

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A numerical analysis of grease thermal elastohydrodynamic lubrication problem using Herschel-Bulkley model (Herschel-Bulkley 모델을 이용한 그리스 열탄성유체윤활 문제의 수치해석)

  • 유진규;김경웅
    • Tribology and Lubricants
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    • v.11 no.3
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    • pp.31-39
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    • 1995
  • Grease thermal elastohydrodynamic lubrication (TEHL) problems of line contacts are analyzed numerically. The effects of temperature and rheological paraineters on grease TEHL are investigated using the Herschel-Bulkley model as a theological model of greases. The pressure distribution, the shape of grease film, mean film temperature and surface temperature of solid wall in line contacts are obtained. It is found that thermal effects on the minimum film thickness become remarkable at high rolling speeds. The effect of yield stress of Herschel-Bulkley model on minimum film thickness is negligible, while the theological index and viscosity parameter have significant effects on minimum film thickness.