Solvent effects on reactivity of solvated electrons with ammonium nitrate in 2-propanol/water mixed solvents

Hyun-Kyung Lee,Tae-Beom Kang 한국공업화학회 2008 Journal of Industrial and Engineering Chemistry Vol.14 No.4

The solvent effects on reactivity of solvated electrons (es ) with ammonium nitrate were studied in 2-propanol/water mixed solvents as a function of solvent composition and temperature. The kinematic viscosities and densities of these mixed solvents were measured as a function of solvent composition and temperature, and the electrical conductances of ammonium nitrate in the mixed solvents were also measured. The measured rate constants of the nearly diffusion controlled reaction were examined according to the Smoluchowski-type models. These models are useful in evaluating the effects of bulk solvents on reactivity of solvated electrons with charged solutes. In the region of 80–100 mol% water, the rate constants for the reaction [es þ ðNO3Þs] increase with the decrease of viscosity. This indicates that the reaction rates in these solvents correspond well to the Smoluchowski–Stokes model. However in the region of 0–20 mol% water, the rate constant for the reaction [es þ ðNH4þÞs] increases with the increase of viscosity. This phenomenon is attributed to the high values of the effective reaction radius (kRr) for the reaction [es þ ðNH4þÞs] in these solvents. The values of kRr (1010 m) in the region of 0–20 mol% water are 4.8–5.7, whereas 2.3–2.6 in the region of 80– 100 mol% water at 298 K. With the exception of the region from 100 to 93 mol% water, the effective diffusion radius (Rd) decreases with the increase of water content. The activation energies of reaction (E2) display having higher values than those of viscosity (Eh) and conductance (EL0 ) in the 2-propanol-rich region, while they become lower than both of Eh and EL0 in the water-rich region, and converge to similar values in almost pure water.

함침 오일 점도에 따른 나노동공 구조의 산화알루미늄 박막의 마찰 및 마멸 거동

김대현(Dae-Hyun Kim),안효석(Hyo-Sok Ahn) 대한기계학회 2013 大韓機械學會論文集A Vol.37 No.5

본 연구는 직경 45 nm인 원통형 나노동공을 가진 산화알루미늄(AAO) 박막에 오일을 함침시켰을 때 동점도가 마찰·마멸에 미치는 영향을 규명하고자 실시하였다. 양극산화법으로 제조한 AAO 박막을 직경 1 mm의 440C 스테인리스 강구를 상대재로 하여 왕복동 미끄럼 접촉시험을 실시하였다. 마찰면과 마멸입자는 주사전자현미경과 에닥스(Energy-dispersive X-ray)를 이용해 분석하였다. 높은 동점도 오일의 윤활효과가 저점도 오일에 비해 크게 향상되었다. 동점도가 낮은 경우엔 모든 하중조건에서 심한 마찰 흔적과 함께 두꺼운 소성변형층이 넓게 형성되었으며 경계윤활막의 손상으로 접촉면에 물질전이와 화학적 반응 현상이 모두 발생하였다. 오일의 점도가 높은 경우 마찰면에 존재하는 경계윤활막이 파괴되지 않아 마찰흔적과 소성변형층의 형성이 매우 적었으며 물질전이와 화학적 반응이 방지되었다. The friction behavior of a 60-μm-thick anodic aluminum oxide (AAO) film having cylindrical nanopores of 45-nm diameter was investigated as a function of impregnated oil viscosity ranging from 3.4 to 392.6 cSt. Reciprocating ball-on-flat sliding friction tests using a 1-mm-diameter steel ball as the counterpart were carried out with normal load ranging from 0.1 to 1 N in an ambient environment. The friction coefficient significantly decreased with an increase in the oil viscosity. The boundary lubrication film remained effectively under all test conditions when high-viscosity oil was impregnated, whereas it was easily destroyed when low-viscosity oil was impregnated. Thin plastic deformed layer patches were formed on the worn surface with high-viscosity oil without evidence of tribochemical reaction and transfer of counterpart material.

경비함정 윤활유의 열화 특성 연구

김득산(Deuksan Kim),서정목(JeongMog Seo),이희진(Heejin Lee) 한국해양환경·에너지학회 2021 한국해양환경·에너지학회 학술대회논문집 Vol.2021 No.5

해양경찰청 소속 경비함정의 성공적인 임무 수행을 위해 효율적인 정비와 운용이 요구되고 있다. 현재 경비함정이 채택한 선박용 디젤기관은 고출력의 MTU와 Pielastick엔진으로 윤활유의 성능이 매우 중요하다. 경비함정의 경우 엔진의 부하 변동이 많고 운행시간 등이 증가되면서 디젤기관에 연료유 혼입 등으로 윤활유 성능을 저하시키는 윤활유 열화가 나타날 수 있다. 연료유가 혼입되면 점도가 감소함으로써 엔진의 출력 감소에 따라 함정 운용에 영향을 줄 수 있다. 최근 3년 동안 경비함정 의뢰 윤활유 분석 결과 연료유 혼입 기준 초과 발생 건이 가장 많이 발생하였다. 따라서 본 연구에서는 윤활유에 연료유를 1%, 2%, 3%, 6%, 10%, 15%로 혼합하여 윤활유 특성을 실험적으로 고찰하였다. 또한 경비함정에서 윤활유 사용 시간별 시료를 채취하여 연료유혼입량, 동점도 등을 확인하였다. 이를 통해 윤활유 성능 저하 원인을 추정하였으며, 경비함정 윤활유의 교체 시기 지연에 따른 엔진 손상을 방지할 것으로 기대된다. Efficient maintenance and operation are required for the successful mission of the KCG velsses. Currently. the marine diesel engine adopted by the KCG velsses are a high-power MTU and pielastick engine, so the performance of lubricating oil is very important. In the case of KCG velsses, as the engine load fluctuates and the operating time increases, the lubricant may deteriorate due to the mixing of fuel oil in the diesel engine, which reduces the performance of the lubricant. When fuel oil is mixed, the viscosity decreases, which can affect the vessles operation as the engine power decreases. In the last 3 years, the analysis of lubricating oil requested by KCG vessels has resulted in the largest number of cases exceeding the standard of fuel dilution. Therefore, in this study, the lubricating oil characteristics were experimentally investigated by fuel dilution with 1%, 2%, 3%, 6%, 10%, and 15% of lubricating oil. In addition, samples for each lubricating oil usage time were collected from the kcg vessles to check the fuel dilution and kinematic viscosity. Through this, the cause of the decrease in the performance of the lubricant oil was estimated, and it is expected to prevent damage to the engine due to the delay in the replacement timing of the lubricant oil for the kcg vessels.

Chemical Composition and Cold Flow Property of Cottonseed Oil Biodiesel Fuel

Yongbin Lai,Junfeng Shu,Xiu Chen,Yinnan Yuan,Lei Zhong,Yuqi Zhang,Menghong Yuan,Bo Wang,Pen Wang 보안공학연구지원센터 2016 International Journal of u- and e- Service, Scienc Vol.9 No.2

The Cottonseed oil methyl ester (COME) was prepared using an alkali - catalyzed trans esterification reaction, and its chemical composition and cold flow properties (CFP) were studied. Two approaches, viz. blending with petrodiesel and treating with cold flow improver (CFI) were used to improve the CFP of COME. The results showed that COME was mainly composed of fatty acid methyl esters (FAMEs): C14:0–C22:0, C16:1–C20:1, C18:2 and C18:3–C20:3. The mass fractions of saturated and unsaturated FAMEs were 27.69% and 71.65%, respectively. The cold filter plugging point (CFPP) and kinematic viscosity (KV) at 40 °C of COME are -1 °C and 4.63 mm2/s respectively. Blending with -10 petrodiesel (-10PD) and 0 petrodiesel (0PD) can decrease the CFPP of COME/-10PD (B30-B40) and COME/0PD (B40-B50) -12 and -8 °C respectively. With the increase in petrodiesel content, the KV at 40 °C of blending oil decreased, and viscosity-temperature characteristics of blending oil were improved. When used Flow Fit (≤3vol.%), the CFPPs were reduce from COME/- 10PD B5, B7, B10, B20, B50 and COME -8, -8, -9, -11, -11 and -1 °C to -28, -27, -26, -25, -16 and -5 °C respectively; COME/0PD -3, -3, -4, -5, -8 and -1 °C to - 26, -25, -24, -24, -16 and -5 °C respectively.

오일 온도에 따른 자동변속기의 마찰 특성에 관한 연구

박상준(Sangjoon Park),이난규(Nankyu Lee),이용규(Yongkyu Lee),박진일(Jinil Park),이종화(Jonghwa Lee) 한국자동차공학회 2012 한국자동차공학회 학술대회 및 전시회 Vol.2012 No.11

Although effects of mechanical friction loss by Transmission is too small than other factors on FTP75 mode, because of heavy regulation about CO₂ and Fuel-economy, most of company try to improve fuel economy for transmission 워머-up using ATF 워머. The transmission friction loss that occur from process of delivery power from engine to wheels is affected by mechanical friction from rotation of gear and temperature of transmission oil. This effect is caused because the oil"s viscosity is influenced by temperature and the mechanical friction of transmission is drop down if the temperature is increased. In this study, the test is processed by the way of comprehending each gear stage"s characteristics by variable oil temperature. The characteristic is tested on a vehicle and the result is compared with theoretical value of kinematic viscosity.

Measurement and modeling of viscosity for binary mixtures of diisopropyl ether with n-alkanes (C7-C10)

Manju Rani,Sanjeev Maken,박소진 한국화학공학회 2019 Korean Journal of Chemical Engineering Vol.36 No.9

The kinematic viscosity (ν) of binary mixture of diisopropyl ether+n-heptane or n-octane or n-nonane or n-decane was measured at 298.15 K, 308.15 and 318.15 K. Using experimental data, the deviation in kinematic viscosity (Δν) was calculated. The Δν follows the sequence: n-heptane<n-octane<n-nonane<n-decane. The kinematic viscosity data were correlated by using various empirical equations suggested by Heric-Brewer, Krishnan-Ladda, Lulian et al. Predicted data using these empirical equations agree well with the experimental data. Kinematic viscosity data was also analyzed by applying the McAllister equation. Dynamic viscosity (η) for binary mixture of diisopropyl ether (DIPE)+n-heptane or n-octane was calculated using density data reported in earlier papers. Deviation in dynamic viscosity (Δη) was also calculated. Bloomfield and Dewan model was used to predict dynamic viscosity, and the predicted values agree well with experimental data for the present binary systems. The Δν and Δη values were fitted to Redlich-Kister polynomial equation. The effect of temperature on kinematic viscosity was also studied.

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℃.

집속체 유동점도와 드래프트 안정성

김종성,허유,Kim, Jong-Seong,Huh, You 한국섬유공학회 2009 한국섬유공학회지 Vol.46 No.4

This research reports on the bundle drafting characteristics on the basis of a mathematical model describing the bundle flow dynamics. And the model parameters were experimentally measured or estimated. The kinematic viscosity of bundle was measured experimentally and the velocity variance parameter was estimated by comparing results from the experiment and from the simulation. The step response of the output bundle thickness to a step change in the draft ratio was applied. The kinematic viscosity of bundle was confirmed to be in the range between $0.5{\times}10^6$ and $8.0{\times}10^6cm^2/s$, which depends on the process conditions. As the draft ratio increases, the viscosity decreases dramatically in a low level of the draft ratio, but a draft ratio higher than 10 causes a very slow change in the viscosity, which is again affected by the roller setting. The kinematic viscosity remained, however, almost unchanged in the level of the roller setting longer than 45 mm. Under the draft ratio larger than 10, a high viscosity and a low velocity variance of constituent fibers had the effect to make the stability area narrower. Therefore the analysis results of bundle flow stability indicate that the draft ratio should be adjusted as small as possible in the high draft ratio level larger than 10 and the entanglement of the bundle be minimized for a large value of the velocity variance parameter, if the bundle flow system is maintained in a dynamic stable state.

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℃.

Effect of kinematic viscosity variation with blended-oil biodiesel on engine performance and exhaust emission in a power tiller engine

Duk Gam Woo,Tae Han Kim 대한환경공학회 2020 Environmental Engineering Research Vol.25 No.6

The optimum conditions for producing biodiesel by combining beef tallow, a waste resource with high saturated fatty acid content, and soybean oil, which has high unsaturated fatty acid content, were investigated. Furthermore, the kinematic viscosity reduction effects of biodiesel by using heating and ultrasonic irradiation were verified, and their impacts on engine performance and exhaust emissions were evaluated. The result shows that the optimum production conditions are a blend ratio of TASO3 (soybean oil to tallow blend ratio of 7:3) and a methanol to oil molar ratio of 12:1. Kinematic viscosity reduction experiment results showed that the kinematic viscosity reduction effects of ultrasonic irradiation and heating were similar, but the heating device is considered more effective because it is simpler and cheaper than the ultrasonic device. Experiment results on output performance and exhaust performance showed that the engine performance and exhaust performance of the fuel with reduced kinematic viscosity were higher than those of the untreated fuel. However, the output of biodiesel was lower than those of conventional diesel (CD) due to the low calorific value of biodiesel; the NOx and CO₂ emissions of biodiesel were higher than those of CD, but the CO and HC emissions of biodiesel were lower.