• Title, Summary, Keyword: Low viscosity

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Analysis on the Friction Characteristics of Low Viscosity Engine Oils (저점도 엔진오일이 마찰특성에 미치는 영향에 관한 해석적 연구)

  • Kim, Chung-Kyun
    • Tribology and Lubricants
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    • v.21 no.6
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    • pp.249-255
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    • 2005
  • In this paper, the friction characteristic of engine bearings has been analyzed in terms of a friction loss power, a minimum film thickness and an oil film pressure. This analysis has been focused on the fuel economy improvement with a low viscosity engine oil such as SAE 0W-40, which is used for a friction loss reduction and increased for a Diesel fuel economy. The friction loss power, the minimum oil film thickness and oil film pressure distribution for plain bearings of a Diesel engine are analyzed using an AVL's EXCITE program with a conventional engine oils of SAE 5W-40 and 10W-40, and a low viscosity engine oil of SAE 0W-40. The computed results indicate that a viscosity of engine oils is closely related to the friction loss power and the decreased minimum film thickness in which is a key parameter of a load carrying capacity of an oil film pressure distribution. When the low viscosity engine oil is supplied to engine bearings, it does not affect to the formation of a minimum oil film thickness. But the friction loss power has been significantly affected by low viscosity engine oil at a low operating temperature of 0. Based on the FEM computed results, the low viscosity engine oil at a low temperature range will be an important factor for an improvement of the fuel economy improvement.

Study on the pre-tilt level and uniformity of low rotational viscosity LC for fast response time

  • Lee, D.J.;Hwang, J.I.;Ko, T.W.;Choi, H.C.;Lee, S.W.
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.457-459
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    • 2005
  • Low viscosity LCs have been developed for fast response time improvement of the TFT-LCD Monitors based on TN mode. This low viscosity characteristic s cause the pretilt angle to be changed and the uniformity to degrade. We have studied on the pretilt angle effect by the various components used for low viscosity LCs. We prepared the panels by using these various components and measured pretilt angle for this research. As a result of this research, we have found out that each low viscosity component has the different pretilt angle level and uniformity. For good display quality, it is important to keep the stable pretilt angle. The low viscosity LCs with this stable pretilt angle make it possible to prepare the high performance TFT-LCD Monitor with both fast response time characteristics and good display quality

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A Study on the Atomization Characteristics of the Ultrasonic-Energy-Added Low Viscosity Biodiesel Blended Fuel (초음파(超音波) 에너지 부가(附加) 저 점도 바이오디젤 혼합연료(混合燃料)의 미립화 특성(微粒化 特性)에 관한 연구(硏究))

  • Song, Yong-Seek;Kim, Yong-Cheol;Ryu, Jung-In
    • Journal of ILASS-Korea
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    • v.9 no.3
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    • pp.1-7
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    • 2004
  • This experiment was undertaken to investigate the atomization characteristics of the low viscosity biodiesel blended fuel and ultrasonic energy added one. Test fuels were conventional diesel fuel and biodiesel fuel. We compared to the characteristics of viscosity and surface tension, SMD between low viscosity biodiesel blended fuel and ultrasonic energy added one. Sauter mean diameter was measured under the variation of the spray distance. Viscosity and surface tension was measured under the variation of the time trace. To measure the droplet size, we used the Malvern system 2600C. Droplet size distribution was analyzed from the result data of Malvern system. Through this experiment, we found that the condition of the ultrasonic energy added situation had smaller Sauter mean diameter of droplet, viscosity and surface tension than that of the conventional situation.

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Fluidity Performance Evaluation of Low Viscosity Typed Superplasticizer for Cement-Based Materials Incorporating Supplementary Cementitious Materials (혼화재료를 치환한 시멘트 계열 재료에 대한 저점도형 고성능 감수제의 유동 성능 평가)

  • Son, Bae-Geun;Lee, Hyang-Seon;Lee, You-Jeong;Han, Dong-Yeop
    • Journal of the Korea Institute of Building Construction
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    • v.19 no.3
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    • pp.219-228
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    • 2019
  • The aim of the research is to provide a fundamental data of low viscosity typed superplasticizer (SP) on cement-based materials incorporating various supplementary cementitious materials (SCMs). As a relatively new product, low-viscosity typed SP has introduced for high performance concrete with high viscosity due to its high solid volume fraction with various SCMs. However, there are not enough research or reports on the performance of the low viscosity typed SP with cement-based materials incorporting SCMs. hence, in this research, for cement paste and mortar, fluidity and rheological properties were evaluated when the mixtures contained various SCMs such as fly ash, blast furnace slag, and silica fume. From the experiment conducted, it was checked that the low viscosity typed superplasticizer decreased the plastic viscosity of the mixture as well as the yield stress. From the results of this research, it is expected to contribute on introduction of new type SP for high performance concrete or high-viscous cementitious materials.

Lubrication Characteristics in Fuel Injection Pump with Variation of Fuel Oils (연료 변경에 의한 연료분사펌프의 윤활 특성)

  • Hong, Sung-Ho
    • Tribology and Lubricants
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    • v.31 no.6
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    • pp.245-250
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    • 2015
  • This study investigates the lubrication characteristics of fuel injection pumps with reference to different fuel oils. Medium-speed diesel engines use fuel oils with various viscosities, such as heavy fuel oil (HFO, which is a high-viscosity fuel oil) and light diesel oil (LDO, which is a low-viscosity fuel oil). When fuel oil with a low viscosity is used, both fuel oil and lubricating oil lubricate the system. Thus, the lubrication of the fuel injection pump is in a multi-viscosity condition when the fuel oil in use changes. We suggest three cases of multi-viscosity models, and divide the fuel injection pump into three lubrication sections: a, the new oil section; b, the mixed oil section; and c, the used oil section. This study compares the lubrication characteristics with variation of the multi-viscosity model, clearance. The volume of Section b does not affect the lubrication characteristics. The lubrication characteristics of the fuel injection pump are poor when high-viscosity fuel oil transfers to low-viscosity fuel oil. This occurs because the viscosity in the new oil section (i.e., Section a) dominates the lubrication characteristics of the fuel injection pump. However, the lubricant oil supply in the used oil section (i.e., Section c) can improve the lubrication characteristics in this condition. Moreover, the clearances of the stem and head significantly influence the lubrication characteristics when the fuel oil changes.

Renewable Low-viscosity Dielectrics Based on Vegetable Oil Methyl Esters

  • Yu, Hui;Yu, Ping;Luo, Yunbai
    • Journal of Electrical Engineering and Technology
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    • v.12 no.2
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    • pp.820-829
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    • 2017
  • Vegetable oil dielectrics have been used in transformers as green alternatives to mineral insulating oils for about twenty years, because of their advantages of non-toxic, biodegradability, and renewability. However, the viscosity of vegetable oils is more than 3 times of mineral oils, which means a poor heat dissipation capacity. To get low-viscosity dielectrics, transesterification and purification were performed to prepare vegetable oil methyl esters in this study. Electrical and physical properties were determined to investigate their potential as dielectrics. The results showed that the methyl ester products had good dielectric strengths, high water saturation and enough fire resistance. The viscosities (at $40^{\circ}C$) were 0.2 times less than FR3 fluid, and 0.7 times less than mineral oil, which indicated superior cooling capacity as we expected. With the assistance of 0.5 wt% pour point depressants, canola oil methyl ester exhibited the lowest pour point ($-26^{\circ}C$) among the products which was lower than FR3 fluid ($-21^{\circ}C$) and 25# mineral oil ($-23^{\circ}C$). Thus, canola oil methyl ester was the best candidate as a low-viscosity vegetable oil-based dielectric. The low-viscosity fluid could extend the service life of transformers by its better cooling capacity compared with nature ester dielectrics.

The Effect of Chitosan on the Rheological Properties of Soymilk and Quality Characteristics of Tofu

  • Han, Jin-Suk;Kim. Mee-Ra
    • Preventive Nutrition and Food Science
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    • v.10 no.3
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    • pp.224-230
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    • 2005
  • The effects of low viscosity chitosan on the rheological properties of soymilk using a model system and on tofu qualities were examined. The flow behavior of soy milk with chitosan closed the Newtonian flow and stabilized according to increasing chitosan concentration. The soymilk containing $glucono-\delta-lactone$ exhibited a more pseudoplastic flow behavior compared with that of the control soymilk. The addition of low viscosity chitosan to the tofu preparation did not significantly affect its physicochemical properties. However, the results of the TEM image and instrumental textural properties showed that low viscosity chitosan affected the construction of the tofu structure. Chitosan tofu had low scores across the whole field of appearance in the sensory evaluation, and its overall eating quality was scored significantly lower. These results suggest that the addition of low viscosity chit os an affects the quality of tofu, which changes according to the degree of polymerization and concentration of chitosan.

Effects of Sugars and Pectin on the Quality Characteristics of Low Sugar Wild Vine (Vitis coignetiea) Jam (당과 펙틴이 저당 머루잼의 품질특성에 미치는 영향)

  • Kim, Moon-Jung;Yoon, Suk-Hoo;Jung, Mun-Yhung;Choe, Eun-Ok
    • Korean journal of food and cookery science
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    • v.24 no.2
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    • pp.206-211
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    • 2008
  • This study investigated the feasibility of manufacturing a low-sugar wild vine jam by examining viscosity, water content, and pH, as affected by sugar and pectin content. The jams were prepared by adding various amounts of sucrose, glucose, or fructose (1.89 M, 2.34 M, 2.63 M, or 2.92 M) and/ or pectin (0%, 0.3%, 0.5%, 0.8%, or 1%) to wild vine juice and heating at $90^{\circ}C$ for 3 hrs. A higher viscosity was shown for the jam manufactured with sucrose as compared to those made with glucose or fructose, and the greater the sucrose level the higher the viscosity of the jam. The jam with 50% reduced sugar content showed a similar viscosity to the control jam, which contained only 2.92 M sucrose, when the sugar was co-added with pectin at 0.5% for the low sucrose jam, and at 0.8% for the low glucose or low fructose jams, respectively. The water content of the low sucrose jam was lower than that of the low glucose or low fructose jams, and adding pectin had no significant effect on the water content of the low sugar jam. The pH levels of the jams were not significantly different, regardless of the type and concentration of sugar, temperature, or pectin addition, and ranged between 3.6 and 3.8. Overall, the results clearly show that wild vine jam with 50% reduced sugar content and having the same viscosity as control jam, can be manufactured when pectin and sugar are added together.

A Study on Viscosity Reducing of Cement-Based Materials by Replacing Byproducts and Adding Low-Viscosity Type HRWR (산업부산물 치환 및 저점도형 고성능 감수제를 사용한 시멘트 계열 재료의 점도저하 방안 연구)

  • Son, Bae-Geun;Han, Dongyeop
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.5 no.4
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    • pp.353-358
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    • 2017
  • The aim of this research is providing a fundamental idea on reducing viscosity of high performance cementitous materials. In rheological aspect, to determine the fluidity of the cementitious materials, both yield stress and viscosity should be controlled. For the high performance cementitious materials with low water-to-binder ratio and high volume fraction, it was difficult to reduce the viscosity with superplasticizer while reducing yield stress was relatively easy. Hence, in this research, with the goal of reducing viscosity of the cementitious materials, both ways of reducing viscosity were suggested: achieving proper combination of powder conditions, and adding low-viscosity typed water reducer. First, by replacing various byproduct powders, specifically, raw coal ash and wasted limestone powder showed favorable results on reducing viscosity of the cement paste. Regarding the low viscosity typed superplasticizer, it showed a good performance on reducing viscosity comparing with generic superplasticizer. Therefore, based on the results of this research, it is expected to provide a fundamental idea on reducing viscosity of cementitious materials by various methods.

Performance of Broiler Chicks Fed Normal and Low Viscosity Rye or Barley with or without Enzyme Supplementation

  • He, T.;Thacker, P.A.;McLeod, J.G.;Campbell, G.L.
    • Asian-Australasian Journal of Animal Sciences
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    • v.16 no.2
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    • pp.234-238
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    • 2003
  • This experiment was conducted to measure nutrient digestibility and performance in broiler chicks fed diets based on normal and low viscosity rye or barley fed with and without enzyme (pentosanase and $\beta$-glucanase) during a 17 day growth trial. A total of 150 one-day old, male broiler chicks (5 birds per pen and 5 pens per treatment) were randomly assigned to one of six dietary treatments in a $3{\times}3$ factorial design experiment (3 cereals${\times}$2 enzyme levels). Digestibility coefficients were determined using chromic oxide. Digestibility coefficients for dry matter and crude protein were significantly (p=0.0001) higher for the barley-based diets than for any of the rye-based diets. Digestibility coefficients for gross energy did not differ (p>0.05) due to cereal grain. There were no differences in the digestibility coefficients for dry matter and gross energy between chicks fed normal and low viscosity rye. However, the digestibility coefficient for crude protein was higher (p=0.01) for the low viscosity rye compared with the normal viscosity rye. Addition of enzyme to the diet significantly (p=0.0001) increased digestibility coefficients for dry matter, crude protein and energy. There were no significant differences in weight gain, feed intake or feed conversion between birds fed barley or rye or between birds fed normal or low viscosity rye. Enzyme supplementation significantly improved (p=0.0001) weight gain, intake and feed conversion. The overall results of this experiment indicate that unsupplemented barley and rye do not support adequate growth rates in poultry. Enzyme supplementation dramatically improved broiler performance. In addition, genetic selection to reduce the viscosity of rye had only a modest effect on the nutritive value of rye for broilers.