• Bulletin of the Korean Chemical Society
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• v.35 no.3
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• pp.811-814
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• 2014

Bio-oil instability, or aging, is a significant problem for the long-term storage of fast pyrolysis oils. We investigated bio-oil aging at the molecular level using Fourier-transform ion cyclotron resonance mass spectrometry. Petroleomic analysis suggests that bio-oil aging is resulted from the oligomerization of phenolic lignin products whereas 'sugaric' cellulose/hemicellulose products have negligible effect.

• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.918-927
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• 2018

Based on the actual operating environment of transformer, the aging tests of nitrile butadiene rubber (NBR) were conducted systematically under four conditions: in air, in transform oil, under compression in air and under compression in transform oil to studythe effect of high temperature, transform oil and compression stress simultaneously on the thermal aging behaviors of nitrile butadiene rubber and predict the lifetime. The effects of liquid media and compression stress simultaneously on the thermal aging behaviors of nitrile butadiene rubber were studied by using characterization methods such as IR spectrosc-opy, thermogravimetric measurements, Differential Scanning Calorimetry (DSC) measurements and mechanical property measurements. The changes in physical properties during the aging process were analyzed and compared. Different aging conditions yielded materials with different properties. Aging at $70^{\circ}C$ under compression stress in oil, the change in elongation at break was lower than that aging in oil, but larger than that aging under compression in air. The compression set or elongation at break as evaluation indexes, 50% as critical value, the lifetime of NBR at $25^{\circ}C$ was predicted and compared. When aging under compression in oil, the prediction lifetime was lower than in air and under compression in air, and in oil. It was clear that when predicting the service lifetime of NBR in oil sealing application, compression and media liquid should be involved simultaneously. Under compression in oil, compression set as the evaluation index, the prediction lifetime of NBR was shorter than that of elongation at break as the evaluation index. For the life prediction of NBR, we should take into account of the performance trends of NBR under actual operating conditions to select the appropriate evaluation index.

• Journal of Ocean Engineering and Technology
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• v.24 no.2
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• pp.53-56
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• 2010

Oil spills and red tide can be very damaging to the environment and fishery farming. These catastrophic accidents must be detected as quickly as possible. In this paper, we report the results of applying the wavelet transform to SAR or marine radar images for the detection of the boundaries of an oil spill or red tide. The application of the wavelet transform to these phenomena looks quite promising in detecting the boundaries of oil spills and red tide areas.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.10
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• pp.481-486
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• 2003

It is well known that a discharge in oil is the source of various physical phenomena. Ultrasonic-wave detection is a useful method to the diagnosis of the transformer-insulation condition. Conventionally, ultrasonic waves are detected by Piezo-electric transducer, and we use optical method that has many advantages. In this paper, we constructed a Mach-Zehnder interferometer with optical fiber and investigated the principle of operation. Test arrangement is based on the needle-plane electrode system in oil and applied AC high voltage. Ultrasonic waves were detected and analyzed with wavelet transform.

• Bulletin of the Korean Chemical Society
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• v.35 no.1
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• pp.165-172
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• 2014

The distribution of basic nitrogen-containing compounds in three vacuum gas oils (VGOs) with different boiling ranges and their dewaxed oils from the lube base oil refining unit of a refinery were characterized by positive-ion electrospray ionization (ESI) Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS). It turned out that the composition of basic nitrogen compounds in the samples varied significantly in DBE and carbon number, and the dominant basic N-containing compounds in these oil samples were N1 class species. $N_1O_1$, $N_1O_2$, and $N_2$ class species with much lower relative abundance were also identified. The composition of basic nitrogen compounds in VGOs and dewaxed VGOs were correlated with increased boiling point and varied in DBE and carbon numbers. The comparison of the analytical results between VGOs and dewaxed VGOs indicated that more basic N-containing compounds in VGO with low carbon number and small molecular weight tend to be removed by solvent refining in lube base oil processing.

• Natural Product Sciences
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• v.1 no.1
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• pp.10-16
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• 1995

A number of microorganisms have been screened for growth on sunflower oil as a sale carbon source for production of useful chemicals. Rhizopus stolonifer NRRL 1478 was found to transform the lipid contents of sunflower oil into dodecyl ${\beta}$-D-glucopyranoside and dodecanedioic acid in 15 and 25% yield respectively. The produced compounds were isolated and purified by column chromatography and its chemical identity were established using MS, IR, $^1H\;and\;^{13}C\;NMR$ spectroscopy.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.49-52
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• 2004

New hydrophobic alumina nanoparticles were synthesized from alumina powders which were hydrophilic nano-agglomerates with diameters from ${\mu}m$ to mm by surface modification. The synthesized hydrophobic alumina nanoparticles which were retreated with Oleic acid were analyzed by Fourier transform infrared spectrophotometer and transmission electron microscopy. Then transformer oil containing surface-modified alumina naonparticles were synthesized. The synthesized hydrophobic alumina nanoparticles were well-dispersed in transformer oil. The coefficient of viscosity and dielectric strength of the Nano-transformer oil were investigated with viscometer and high voltage experiment device. In this study, the thermal conductivity of Nano-transformer oil was investigated to reduce the oil temperature of transformer by transient hot-wire method.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1989.10a
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• pp.65-70
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• 1989

This paper presents resarch results on the use of a corona detector and a pulse counter in order to diagnose for oil transformers. Using these experimental apparatus, tests were carried out on a typical transformer oil containing different carbonized paper and various moisture contents to measure the picocoulomb val-ues and pulse count. Through the result of this study it was found that the picocoulomb values and pulse count of corona were depended on the getting stained in transformer oil. The amplitude of the partial discharge amount and the number of pulse were decreased up to 70 [。c] and then was increased as the oil temperature goes up. It was concluded that the determinati-on level for diagnosis of oil transform-er was taken into account the temperatu-er of transformer oil, The use of pulse counter method, which have been taken the same property of voltage and temperature variation for the corona measurement mothod, considera-bly increase insulator avilability.

• Environmental Engineering Research
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• v.22 no.4
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• pp.384-392
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• 2017

Mango shell (MS) and mango shell activated carbon (MSAC) was used to adsorb crude oil from water at various experimental conditions. The MSAC was prepared by carbonization at $450^{\circ}C$ and chemical activation using strong $H_3PO_4$ acid. The adsorbents were characterized with Fourier Transform Infrared spectroscopy. Investigations carried out included the effects of parametric variations of different adsorbate dose, adsorbent dose, time, temperature, pH and mixing speed on the adsorption of crude oil. The equilibrium isotherm for the adsorption process was determined using Langmuir, Freundlich, Temkin and Dubinin Radushkevich isotherm models. Temkin isotherm was found to fit the equilibrium data reasonably well than others. The result demonstrated that MSAC was more effective for crude oil adsorption than raw mango shell. Optimum conditions were also presented. The enhanced effect from activation was justified statistically using Analysis of Variance and Bonferroni-Holm Posthoc significance test. The pseudo first order kinetics gave a better fit for crude oil adsorption with both MS and MSAC.

• Applied Chemistry for Engineering
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• v.32 no.3
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• pp.357-360
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• 2021

Emulsions were prepared using a mixture of bio-oil obtained from the pyrolysis of sawdust in an N₂ environment and Quercus mongolica in a CH₄ environment for both non-catalytic and catalytic cases. Both prepared emulsions were examined by measuring the physical stability and Fourier transform infrared spectroscopy. The emulsion with HLB 5.8 (Span 80 and Atlox 4916) for the ratio of bio-oil (B-oil and C-oil): surfactant: diesel = 10% : 3% : 87% showed stability for 15 days. Combining oils produced in N₂ and CH₄ environments could be a potential solution for generating high-quality emulsions with a high heating value.