Additive properties of saturated very long chain fatty acids in castor and jojoba oils

C. V. Ossia,H. G. Han,공호성 대한기계학회 2008 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.22 No.8

Tribological and oxidation stability properties of saturated very-long-chain-fatty acids present in castor and jojoba oils have been investigated by the four ball tribosystem, pressure differential scanning calorimetry, optical micrographs and electron probe micro-analysis (EPMA). Test results of the oils additized with eicosanoic and octadecanoic acids in the oils were compared with those of zinc dialkyldithiophosphate (ZDTP). Results showed that eicosanoic and octadecanoic acids possessed better antiwear and lubricity properties compared to the popular ZDTP, though with reduced oxidation stability. EPMA and optical micrographs of worn surface morphology showed that lubricating films formed by these acids were metallic salts whose breakdown was not associated with tribochemical wear surface modification of the mating pairs.

Chromatic Parameters in the Condition Monitoring of Synthetic Hydraulic Oils

C.V. Ossia,H. Kong,H.G. Han,L. Markova,V. Makarenko 한국트라이볼로지학회 2007 KSTLE International Journal Vol.8 No.1

Chromatic device was developed using light emitting diodes, optic fibers and photodiodes. Chromatic ratio and total contamination parameters based on transmitted light intensity in Red, Green, and Blue wavelengths were used for oil chemical and particulate contamination assessment. Chromatic ratio criterion was found independent of the particulate contamination of oil; but depended on chemical degradation, being more sensitive for synthetic than mineral hydraulic oil. Total contamination index of the sensor depended on both the chemical degradation and particulate contamination ofthe oil, being most sensitive in blue wavelength, and least in the red. Test results for synthetic hydraulic oils monitored corroborated with results of other tests such as viscosity, total acid number, elemental optical emission spectroscopy, particulate counts and UV- VIS photospectrometry. Chromatic ratio showed a clearer indication of oil degradation, compared to key monitoring parameters such as total acid number, viscosity and particle counts. The results showed that these parameters are effective criteria for the condition monitoring of synthetic hydraulic oils.

CHROMA TIC PARAMETERS IN THE CONDITION MONITORING OF SYNTHETIC HYDRAULIC OILS

C.V. Ossia,H. Kong,H.G. Han,L. Markova,V. Makarenko 한국트라이볼로지학회 2007 한국트라이볼로지학회 학술대회 Vol.2007 No.6

Chromatic device was developed using light emitting diodes, optic fibers and photodiodes. Chromatic ratio and total contamination parameters based on transmitted light intensity in Red, Green, and Blue wavelengths were used for oil chemical and particulate contamination assessment. Chromatic ratio criterion was found independent of the particulate contamination of oil; but depended on chemical degradation, being more sensitive for synthetic than mineral hydraulic oil. Total contamination index of the sensor depended on both the chemical degradation and particulate contamination of the oil, being most sensitive in blue wavelength, and least in the red. Test results for synthetic hydraulic oils monitored corroborated with results of other tests such as viscosity, total acid number, elemental optical emission spectroscopy, particulate counts and UV - VIS photospectrometry. Chromatic ratio showed a clearer indication of oil degradation, compared to key monitoring parameters such as total acid number, viscosity and particle counts. The results showed that these parameters are effective criteria for the condition monitoring of synthetic hydraulic oils.

Chromatic Parameters in the Condition Monitoring of Synthetic Hydraulic Oils

Ossia, C.V.,Kong, H.,Han, H.G.,Markova, L.,Makarenko, V. Korean Tribology Society 2007 KSTLE International Journal Vol.8 No.1

Chromatic device was developed using light emitting diodes, optic fibers and photodiodes. Chromatic ratio and total contamination parameters based on transmitted light intensity in Red, Green, and Blue wavelengths were used for oil chemical and particulate contamination assessment. Chromatic ratio criterion was found independent of the particulate contamination of oil; but depended on chemical degradation, being more sensitive for synthetic than mineral hydraulic oil. Total contamination index of the sensor depended on both the chemical degradation and particulate contamination of the oil; being most sensitive in blue wavelength, and least in the red. Test results for synthetic hydraulic oils monitored corroborated with results of other tests such as viscosity, total acid number, elemental optical emission spectroscopy, particulate counts and UV-VIS photospectrometry. Chromatic ratio showed a clearer indication of oil degradation, compared to key monitoring parameters such as total acid number, viscosity and particle counts. The results showed that these parameters are effective criteria for the condition monitoring of synthetic hydraulic oils.

고분자량 점도지수향상제가 첨가된 오일의 음향점도 특성

공호성(H. Kong),C.V. Ossia,한흥구(H.G. Han) 한국트라이볼로지학회 2009 한국트라이볼로지학회지 (Tribol. Lubr.) Vol.25 No.4

Oil viscosity is one of the important parameters for machinery condition monitoring. Basically, it is expressed as kinematic viscosity measured by capillary flow and dynamic or absolute viscosity measured by rotary shear viscometry. Recently, acoustic wave techniques appear in the market, measuring viscosity as the product of dynamic viscosity and density. For Newtonian fluids, knowledge of density allows conversion from one viscosity parameter to the other at a specific shear rate and temperature. In this work, oil samples with different chain lengths of viscosity index (Ⅵ) improvers and concentrations were examined by different viscometric techniques. Results showed that acoustic viscosity measurements give misleading results for oil samples with high molecular weight Ⅵ improvers and at low temperatures s 40℃.

기계 상태진단을 위한 인-라인형 오일 모니터링 스마트 센서

공호성(H. Kong),오씨아 빅터(C.V. Ossia),한흥구(H.G. Han),류보브 마르코바(L. Markova) 한국트라이볼로지학회 2008 한국트라이볼로지학회지 (Tribol. Lubr.) Vol.24 No.3

An integrated in-line oil monitoring detector assigned for continuous in situ monitoring multiple parameters of oil performance for predicting economically optimal oil change intervals and equipment condition control is presented in this study. The detector estimates oil deterioration based on the information about chemical degradation, total contamination, water content of oil and oil temperature. The oil oxidation is estimated by "chromatic ratio", total contamination is measured by the changes in optical intensity of oil in three optical wavebands ("Red", "Green" and "Blue") and water content is evaluated as Relative Saturation of oil by water. The detector is able to monitor oils with low light absorption (hydraulic, transformer, turbine, compressor and etc. oils) as well as oils with rather high light absorption in visible waveband (diesel and etc. oils). In a case study that the detector is applied to a diesel engine oil, it is found that the detector provides good results on oil chemical degradation as well as soot concentration.

오일 열화 진행에 따른 오일의 색채 특성 변화

공호성(H. Kong),오씨아 빅터(C.V. Ossia),한흥구(H.G Han),류보브 마르코바(L. Markova) 한국트라이볼로지학회 2008 한국윤활학회지(윤활학회지) Vol.24 No.1

In this work, a simple and low cost sensor technique is proposed to test oil color in real time using in-line sensor. It is presented to use a ratio of intensity in red wavelength range to intensities of green and blue wavelength ranges (defined as a 'chromatic ratio') in order to estimate the oil color change. The proposed sensor technique is realized by irradiating a white LED as light source and a RGB color sensor as photoreceiver, and the chromatic ratio of various types of used oils are measured. The results show that chromatic ratio generally reflects chemical deterioration of oil, including oil oxidation and thermal degradation. It is concluded that the proposed sensor could be used for an effective oil monitoring technology.

고분자량 점도지수향상제가 첨가된 오일의 음향점도 특성

공호성(H. Kong),오씨아 빅터(C.V. Ossia),한흥구(H.G. Han) 한국트라이볼로지학회 2009 한국트라이볼로지학회 학술대회 Vol.2009 No.6

Oil viscosity is one of the important parameters for machinery condition monitoring. Basically, it is expressed as kinematic viscosity measured by capillary flow and dynamic or absolute viscosity measured by rotary shear viscometry. Recently, acoustic wave techniques appear in the market, measuring viscosity as the product of dynamic viscosity and density. For Newtonian fluids, knowledge of density allows conversion from one viscosity parameter to the other at a specific shear rate and temperature. In this work, oil samples with different chain lengths of viscosity index (VI) improvers and concentrations were examined by different viscometric techniques. Results showed that acoustic viscosity measurements give misleading results for oil samples with high molecular weight VI improvers and at low temperatures ≤ 40℃.