• Tribology and Lubricants
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• 제22권4호
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• pp.211-217
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• 2006

Ring and groove wear may not be a problem in most current automotive engines. However, a small change in ring face and groove geometry can significantly affect the lubrication characteristics and ring axial motion. This in turn can cause to change inter-ring pressure, blow-by and oil consumption in an engine. Therefore, by predicting the wear of piston ring face, ring groove and cylinder bore altogether, the changed ring end gap and the changed volume of gas reservoir can be calculated. Then the excessive oil consumption can be predicted. Being based on the calculation of gas flow amount by the theory of piston ring dynamics and gas flow, and the calculation of oil film thickness and friction force by the analysis of piston ring lubrication, the calculation theory of oil amount through top ring gap into combustion chamber will be set. This is estimated as engine oil consumption. Furthermore, the wear theories of ring, groove and cylinder bore are included. Then the each amount of wear is to be obtained. The changed oil consumption caused by the new end gap and the new volume of oil reservoir around second land, can be calculated at some engine running interval. Meanwhile, the wear amount and oil consumption occurred during engine durability cycle are compared with the calculated values. Next, the calculated amount of oil consumption and wear are compared with the guideline of each part's wear and oil consumption. So, the timing of part repair and engine life cycle can be predicted in advance without performing engine durability test. The wear data of rings and grooves are obtained from three engines before and after engine durability test. The calculated wear data of each part are turn out to be at the lower bound of aver-aged test values or a little below.

• Tribology and Lubricants
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• 제25권6호
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• pp.387-398
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• 2009

The operation condition of recently designed pistons for high power and high speed diesel engine become more severe due to the increment of combustion pressure and temperature. So, in order to overcome high temperature, the application of the mono-metal cast aluminum alloy piston featuring an enclosed cast-in open cooling gallery has increased. In this research, it is developed a PCJ (piston cooling jet) rig tester, described the test procedure and validated the performance of sample piston cooling gallery design. Then the test rig will be used for developing the design technology of piston cooling gallery. The test rig is composed with oil reservoir and pumping system, oil jet system, piston fixing and moving system, collecting oil measuring system, and data measuring and recording system. It will be measured collecting efficiencies under conditions of a few piston positions, oil jet pressures and oil viscosities for a piston cooling gallery. Furthermore, the PCJ rig tester will be used for the optimum design of the oil cooling gallery which being applied to increase the cooling efficiency of pistons in diesel engines satisfying the EURO V emission regulation and the more.

• Journal of Ginseng Research
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• 제37권4호
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• pp.468-474
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• 2013

Ginseng seed oil was prepared using compressed, solvent, and supercritical fluid extraction methods of ginseng seeds, and the extraction yield, color, phenolic compounds, fatty acid contents, and phytosterol contents of the ginseng seed oil were analyzed. Yields were different depending on the roasting pretreatment and extraction method. Among the extraction methods, the yield of ginseng seed oil from supercritical fluid extraction under the conditions of 500 bar and $65^{\circ}C$ was the highest, at 17.48%. Color was not different based on the extraction method, but the b-value increased as the roasting time for compression extraction was increased. The b-values of ginseng seed oil following supercritical fluid extraction were 3.54 to 15.6 and those following compression extraction after roasting treatment at $200^{\circ}C$ for 30 min, were 20.49, which was the highest value. The result of the phenolic compounds composition showed the presence of gentisic acid, vanillic acid, ferulic acid, and cinnamic acid in the ginseng seed oil. No differences were detected in phenolic acid levels in ginseng seed oil extracted by compression extraction or solvent extraction, but vanillic acid tended to decrease as extraction pressure and temperature were increased for seed oil extracted by a supercritical fluid extraction method. The fatty acid composition of ginseng seed oil was not different based on the extraction method, and unsaturated fatty acids were >90% of all fatty acids, among which, oleic acid was the highest at 80%. Phytosterol analysis showed that ${\beta}$-sitosterol and stigmasterol were detected. The phytosterol content of ginseng seed oil following supercritical fluid extraction was 100.4 to 135.5 mg/100 g, and the phytosterol content following compression extraction and solvent extraction was 71.8 to 80.9 mg/100 g.

• 청정기술
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• 제25권2호
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• pp.168-176
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• 2019

Spent coffee is one of biomass sources to be converted into bio-oil. However, the bio-oil should be further upgraded to achieve a higher quality bio-oil because of its high oxygen content. Deoxygenation under hydrotreating using different catalysts (catalytic hydrodeoxygenation; HDO) is considered as one of the promising methods for upgrading bio-oil from pyrolysis by removal of O-containing groups. In this study, the HDO of spent coffee bio-oil, which was collected from fast pyrolysis of spent coffee ($460^{\circ}C$, $2.0{\times}U_{mf}$), was carried out in an autoclave. The product yields were 72.16 ~ 96.76 wt% of bio-oil, 0 ~ 18.59 wt% of char, and 3.24 ~ 9.25 wt% of gas obtained in 30 min at temperatures between $250^{\circ}C$ and $350^{\circ}C$ and pressure in the range of 3 to 9 bar. The highest yield of bio-oil of 97.13% was achieved at $250^{\circ}C$ and 3 bar, with high selectivity of D-Allose. The carbon number distribution of the bio-oil was analyzed based on the concept of simulated distillation. The $C_{12}{\sim}C_{14}$ fraction increased from 22.98 wt% to 27.30 wt%, whereas the $C_{19}{\sim}C_{26}$ fraction decreased from 24.74 wt% to 17.18 wt% with increasing reaction time. Bio-oil yields were slightly decreased when the HZSM-5 catalyst and dolomite were used. The selectivity of CO was increased at the HZSM-5 catalyst and decreased at the dolomite.

• Journal of Pharmaceutical Investigation
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• 제16권2호
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• pp.68-71
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• 1986

Oil in water microemulsion which has many pharmaceutical applications was prepared and evaluated. As oil sources and emulsifier, two grades of oil and egg phosphatide were used, respectively. Vacuum high shear mixing and high pressure homogenizing were performed and in the homogenizing step, effect of the number of passes in the homogenizer on the stability of microemulsion was studied, using Coulter counter, photographic microscope and pH-meter. From above results, it was concluded that the stability of microemulsion made of refined soy-bean oil was better than that of food grade soybean oil and by five passes in the homogenizer at 6,000 psi, we could make stable microemulsion with average particle diameter below $1\;{\mu}m$, with no particle above $5\;{\mu}m$ and no significant change during 6 weeks stored.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.590-595
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• 2006

This paper presents the friction and anti-wear characteristics of nano-oil with a mixture of a refrigerant oil and carbon nano-particles in the thrust slide-bearing of scroll compressors. Frictional loss in the thrust slide-bearing occupies a large part of total mechanical loss in scroll compressors. The characteristics of friction and anti-wear using nano-oil are evaluated using the thrust bearing tester for measuring friction surface temperature and the coefficient of friction at the thrust slide-bearing as a function of normal loads up to 4,000 N and orbiting speed up to 3,200 rpm. It is found that the coefficient of friction increases with decreasing orbiting speed and normal force. The friction coefficient of carbon nano-oil is 0.015, while that of pure oil is 0.023 under the conditions of refrigerant gas R-22 at the pressure of 5 bars. It is believed that carbon nano-particles can be coated on the friction surfaces and the interaction of nano-particles between surfaces can be improved the lubrication in the friction surfaces. Carbon nano-oil enhances the characteristics of the anti-wear and friction at the thrust slide-bearing of scroll compressors.

• 한국축산식품학회지
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• 제32권1호
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• pp.68-76
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• 2012

본 연구는 식물성 유지를 첨가한 저급우육 등심의 초고압 처리가 저급우육의 물리화학적, 미생물학적 품질에 미치는 영향을 평가하기 위해서 실시되었다. 저등급 우육 중량의 10%(w/w) 식물성유지인 올리브유와 포도씨유를 첨가 하여 진공포장 후 600 MPa의 초고압에서 처리하였으며 0.1 MPa 처리군과 표면 육색, 조직감, 지방산, 관능평가, 일반 미생물 및 병원성 미생물학적 품질차이검사를 실시하였다. 표면 육색은 600 MPa 처리군이 0.1 MPa 처리군에 비해 $L^*$ 값과 $b^*$ 값이 유의적으로 높았으며 $a^*$ 값은 유의적으로 낮았으며(p<0.05), 저장 10일 후에도 유사한 경향을 보였다. 초고압 처리된 우육의 조직감은 초고압 무처리구(0.1 MPa)와 유의적인 차이가 없었다(p>0.05). 지방산 조성 분석 결과 600 MPa 처리군중 올리브유 첨가구와 포도씨유 첨가구에서 각각 oleic acid와 linoleic acid가 유의적으로 높게 분석되었다(p<0.05). 일반 미생물학적 품질 평가 결과 저장 초기 600 MPa 처리군에서 검출되지 않았으나 0.1 MPa 처리군에서 3 Log CFU/g 수준으로 검출되었으며 저장 10일 후 0.1 MPa에서 6 Log CFU/g 수준까지 증가 한 반면 600 MPa 처리군 중 포도씨유 첨가구만 2 Log CFU/g 정도의 증가만 보였다. 병원성 미생물 접종시험 결과 600 MPa 처리시 E. coli와 L. monocytogenes 모두 저장 초기(저장 0일 차) 및 저장 10일 후 검출되지 않은 반면 0.1 MPa 처리군은 저장 초기에 초기 접종 농도인 7 Log CFU/g 수준으로 측정되었으며 저장 10일 후 역시 7 Log CFU/g 수준을 유지 하였다. 관능평가에서 종합적 기호도와 구매의사 항목에선 모든 시험구에서 유의적인 차이를 나타내지 못하였다(p>0.05). 연구결과 저급우육에 식물성 유지를 첨가하여 초고압 기술을 적용할 경우 병원성 미생물에 대한 안전성 확보와 식물성 유지 첨가에 의한 지방산 조성의 변화를 가져올 수 있다고 판단된다. 또한 올리브유 첨가를 통해 초고압 시 발생되는 지방산패를 억제할 수 있는 가능성을 보였다.

• Tribology and Lubricants
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• 제6권1호
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• pp.52-56
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• 1990

The Lubrication Mode of line contacts between the vane and camring in an oil hydraulic vane pump with intravanes has been investigated. Variations of the radial acting force of a vane were calculated from previously measured results of dynamic internal pressure in four chambers surrounding a vane, and variations of the lubrication mode were estimated in both the rotational speed range from 500 to 1500 rpm and in the delivery pressure range from 1 to14 Mpa. The results indicate the variations of the radial acting force. It is found that the regimes of lubrication in the vane tip contacts cover rigid-isoviscous to rigid-variable viscosities.

• Tribology and Lubricants
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• 제19권1호
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• pp.15-20
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• 2003

The purpose of the paper is to investigate the effects of design parameters on the noise of a rotor- bearing system supported in oil lubricated journal bearings. Effects of radial clearance and width of the bearing, lubricant viscosity and mass eccentricity of the rotor are also examined. Numerical results of the parametric studies are summarized through graph for the A-weighted sound pressure level of the bearing with respect to the rotational speed of the rotor. Results show that the sound pressure level of the bearing is markedly influenced by the mass eccentricity of the rotor and the radial clearance and the width of the bearing. The high viscosity of the lubricant slightly decreases the noise of the bearing, but its effect is relatively very low at high speed. The results of the paper could be an aid in the low noise design of rotor-bearing system supported in oil lubricated journal bearings.

• 한국산업융합학회 논문집
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• 제7권4호
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• pp.341-348
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• 2004

This study experimented dividing compaction load by dynamic compaction test and an oil pressure hammer compaction test for consolidation strength characteristics experimental feedback about soil change aspect of waste landfill ground and revelation of compaction effect as underground research about consolidation behavior of waste landfill ground by compaction load, foot weight and percussion number of times were adapted differently each other with uniformity drop head when dynamic compaction test, and hammer scale and percussion number of times were adapted differently also when oil pressure hammer compaction test.