• Title/Summary/Keyword: 소진조건

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Comparison of Oxidative Stability for the Thermally-oxidized Vegetable Oils using a DPPH Method (DPPH법에 의한 식용유지의 열산화 안정성 비교)

  • Lee, Jae-Min;Chang, Pahn-Shick;Lee, Jae-Hwan
    • Korean Journal of Food Science and Technology
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    • v.39 no.2
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    • pp.133-137
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    • 2007
  • The 2,2-diphenyl picrylhydrazyl (DPPH) method, which can be used to predict the oxidative stability of edible oils, was previously reported by our research group. Not only free radical scavenging antioxidants but also radicals from oxidized oils are capable of reacting with DPPH radicals, thereby reducing the absorbance of DPPH. In this study, the optimum sample size of edible oils for the DPPH method was determined, and the oxidation of the edible oils was monitored via DPPH, coupled with other conventional methods. The optimum sample size was determined as 1.5 g using soybean oil. Soybean, corn, virgin olive, and refined olive oils were thermally oxidized for 3 hr at $180^{\circ}C$ and analyzed via DPPH, conjugated dienoic acid (CDA) value, and p-anisidine value (p-AV) protocols. Soybean and corn oils were found to be more sensitive to thermal oxidation than virgin and refined olive oils, on the basis of the CDA value and p-AV measurements. The DPPH method can indicate the inherent radical scavenging activity of unoxidized samples, the time required for the depletion of antioxidants, and the rate of degradation of the antioxidants. The soybean and corn oils evidenced higher levels of free radical scavenging compounds, required more time for the consumption of inherent antioxidants, and also manifested steeper antioxidant degradation rates than olive oils, based on the results of DPPH analysis. The DPPH method, accompanied by other conventional methods, may prove useful in predicting the degree of oxidation of vegetable oils.

Crevice Corrosion Properties of PWR Structure Materials Under Reductive Decontamination Conditions (환원제염조건에서 가압경수로 구조재료의 틈부식 특성)

  • Jung, Jun-Young;Park, Sang Yoon;Won, Hui Jun;Choi, Wang Kyu;Moon, Jei Kwon;Park, So Jin
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.12 no.3
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    • pp.199-209
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    • 2014
  • Crevice corrosion tests were conducted to examine the corrosion properties of HYBRID (HYdrazine Base Reductive metal Ion Decontamination) which was developed to decontaminate the PWR primary coolant system. To compare the corrosion properties of HYBRID with commonly existing decontamination agents, oxalic acid (OA) and citric oxalic acid (CITROX) were also examined. Type 304 Stainless Steel (304 SS) and Alloy 600 which are major components of the primary coolant system in Pressurized Water Reactor (PWR) were evaluated. Crevice corrosion tests were conducted under very aggressive conditions to confirm quickly the corrosion properties of primary coolant system structure components which have high corrosion resistance. Pitting and IGA were occurred in crevice surface under OA and CITROX conditions. But localized corrosion was not observed under HYBRID condition. Very low corrosion rate of less than $1.3{\times}10^{-3}{\mu}m/h$ was observed under HYBRID condition for both materials. On the other hand, under OA condition, Alloy 600 indicated comparatively uniform corrosion rate of $4.0{\times}10^{-2}{\mu}m/h$ but 304 SS indicated rapid accelerated corrosion in lower case than pH 2.0. In case of HYBRID condition, general corrosion and crevice corrosion were scarcely occurred. Therefore, material integrity of HYBRID in decontamination of primary coolant system in pressurized water reactor (PWR) reactor was conformed.

The Influence of Location Uncertainty and Visibility of Targets on the Strength of Attentional Blink (표적 위치의 불확실성과 표적 가시성이 주의깜박거림 강도에 미치는 영향)

  • Kim, Giyeon;Hyun, Joo-Seok
    • Korean Journal of Cognitive Science
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    • v.27 no.2
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    • pp.275-301
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    • 2016
  • Attentional blink (AB) refers to the phenomena where conscious report for a target (T2) subsequent to the first target (T1) in a stream of items under rapid serial visual presentation (RSVP) becomes difficult if the T2 follows no later than 500ms after the T1. The present study examined the effect of T1 visibility on T2 AB strength according to the bottleneck account proposing that the amount of allocated resources for T1 memory consolidation determines the strength of AB against T2. In the low-visibility condition, the T1 had a gray color for a low stimulus contrast against the black background whereas had a bright and saturated color in the high-visibility condition. In both visibility conditions, the T1 was also highly distinct from the remaining distractors. A multi-RSVP method was also used for increasing location uncertainty of the targets supposedly consuming on average attentional resources for the targets. Two experiments revealed that AB strength was more intense in the low-visibility than high-visibility condition, and the pattern of difference went more pronounced if T2 visibility was improved. The results indicate that T1 visibility can affect more strongly when attentional resources are relatively lacking for resolving the T1 bottleneck, and support for the bottleneck account proposing that the level of T1's visibility can determine the intensity of the T1 bottleneck.

Production of Dendropanax morbiferus extract containing multi-functional ingredients by serial fermentation using Bacillus subtilis HA and Lactobacillus plantarum KS2020 (고초균-젖산균의 순차적 복합 발효를 통한 복합 기능성 물질 함유 황칠나무 추출물의 생산)

  • Su-Jin Son;Hye-Mi Kang;Yun-Ho Park;Mi-Hyang Hwangbo;Sam-Pin Lee
    • Food Science and Preservation
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    • v.31 no.1
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    • pp.138-148
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    • 2024
  • The production of poly-γ-glutamic acid (γ-PGA) and γ-aminobutyric acid (GABA) was optimized by serial fermentation of Dendropanax morbiferus extract (DME) using Bacillus subtilis HA and Lactobacillus plantarum KS2020. The 1st alkaline fermentation was performed on 60% DME including 2% glucose and 10% monosodium ʟ-glutamate (MSG) as a precursor. The 1st fermented DME had 57 mg% tyrosine. Consequently, the 2nd lactic acid fermentation for 5 days increased the tyrosine content of 106 mg%. The mucilage containing γ-PGA showed a high content of 3.50% on the first day of alkaline fermentation and then increased to 4.10% after 2 days. The precursor (MSG) remaining in the 1st fermented DME was efficiently converted to GABA by the 2nd lactic acid fermentation in the presence of 5% skim milk, 1.5% glucose and 0.5% yeast extract, resulting in the production of 18.29 mg/mL GABA. The viable cells of lactic acid bacteria increased and indicated 9.49 log CFU/mL on the fermentation for 5 days, and the acidity of co-fermented DME indicated the highest value of 1.55%. Conclusively, the serial fermented DME has multi-functional ingredients containing γ-PGA, GABA, peptides and probiotics.

Efficient Clustering Algorithm based on Data Entropy for Changing Environment (상황변화에 따른 엔트로피 기반의 클러스터 구성 알고리즘)

  • Choi, Yun-Jeong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.10 no.12
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    • pp.3675-3681
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    • 2009
  • One of the most important factors in the lifetime of WSN(Wireless Sensor Network) is the limited resources and static control problem of the sensor nodes. In order to achieve energy efficiency and network utilities, sensor nodes can be well organized into one cluster and selected head node and normal node by dynamic conditions. Various clustering algorithms have been proposed as an efficient way to organize method based on LEACH algorithm. In this paper, we propose an efficient clustering algorithm using information entropy theory based on LEACH algorithm, which is able to recognize environmental differences according to changes from data of sensor nodes. To measure and analyze the changes of clusters, we simply compute the entropy of sensor data and applied it to probability based clustering algorithm. In experiments, we simulate the proposed method and LEACH algorithm. We have shown that our data balanced and energy efficient scheme, has high energy efficiency and network lifetime in two conditions.

Improvement of Chlorophyll-photosensitized Oxidation of Fish Oil-enriched Emulsion by Sesame Oil Addition and Antioxidant Content Changes (참기름 첨가에 의한 어유 보강 에멀젼의 클로로필에 의한 광산화 개선 효과와 산화 방지제 함량 변화)

  • An, Sojin;Lee, Edwald;Choe, Eunok
    • Korean Journal of Food Science and Technology
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    • v.46 no.2
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    • pp.127-134
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    • 2014
  • This study was performed to evaluate the effects of sesame oil addition to a tuna oil-enriched emulsion during chlorophyll-photosensitized oxidation. The emulsion principally consisted of tocopherol-stripped canola and tuna oil with or without sesame oil, acetic acid, phospholipids, and xanthan gum. Chlorophyll b was added to promote the production of singlet oxygen upon exposure to light. The oxidation of oil in the emulsion was evaluated by determining the peroxide value (POV) and conjugated dienoic acid (CDA) contents. Concentrations of minor compounds in the emulsion were monitored. Increasing POV and CDA contents in the emulsion were paralleled with decreased docosahexaenoic acid during oxidation, and oxidation was inhibited by the addition of sesame oil. Chlorophyll, polyphenols, tocopherol, and phospholipids were degraded during oxidation of the emulsion; however, their degradation was slowed down by the addition of sesame oil. Lignans in the emulsions containing added sesame oil were barely changed, suggesting that they quenched singlet oxygen physically. Polyphenols were the most effective in improving the stability of tuna oil-enriched emulsions during chlorophyll-photosensitized oxidation.

Effect of Cooling Rate and Crystallizer Type on the Separation of Naphthalene Mixture by Layer Melt Crystallization (경막형 용융결정화에 의한 나프탈렌 혼합물의 분리에 관한 냉각속도와 결정화기 형태의 영향)

  • Kang, So-Rim;Koh, Joo-Young;Kim, Chul-Ung;Park, So-Jin
    • Clean Technology
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    • v.13 no.1 s.36
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    • pp.72-78
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    • 2007
  • As a basic research fur the separation of effective components included in pyrolysis gas oil, the crystallization on each system of naphthalene with 2-methylnaphthalene, indene and 1-methylnaphthalene as impurity has been carried out in column and cold-finger type crystallizer, respectively. In crystallization operation, the purity of naphthalene has been a tendency of increase with decreasing of cooling rate and in the presence of impurity with lower melting point. In comparison of crystallizer types, naphthalene purity in column type crystallizer was a higher value than that in cold-finger type due to effective sweating operation after crystallization.

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Study on Characteristic of Self-preservation Effect of CO2 Hydrate according to Temperature, Particle Diameter and Shape (온도, 직경, 형태에 따른 CO2 하이드레이트의 자기보존효과 특성 연구)

  • Kim, Yeon-Soo;Kang, Seong-Pil;Park, So-Jin
    • Korean Chemical Engineering Research
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    • v.51 no.5
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    • pp.602-608
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    • 2013
  • Gas hydrate studies are attracting attention of many researchers as an innovative, economic and environmentally friendly technology when it is applied to $CO_2$ capture, transport, and storage. In this study, we investigated whether $CO_2$ hydrate shows the self-preservation effect or not, that is the key property for developing a novel $CO_2$ transport/storage method. Especially the degree of self-preservation effect for $CO_2$ hydrate was studied according to the particle size of $CO_2$ hydrate samples. We prepared three kinds of $CO_2$ hydrate samples varying their particle diameter as millimeter, micron and nano size and measured their change of weight at $-15{\sim}-30^{\circ}C$ under atmospheric pressure during 3 weeks. According to our experimental result, the lower temperature, larger particle size, and compact structure for higher density are the better conditions for obtaining self-preservation effect.

Isothermal Vapor-Liquid Equilibria at 333.15K and Thermodynamic Excess Properties for the Binary System of Methanol+Dimethyl Carbonate (Methanol+Dimethyl Carbonate 혼합계의 333.15 K 등온 기-액 평형과 열역학 과잉 물성)

  • Han, Kyu-Jin;Park, So-Jin
    • Korean Chemical Engineering Research
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    • v.43 no.3
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    • pp.387-392
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    • 2005
  • Recently, dimethyl carbonate (DMC) is considered as an alternative of MTBE (methyl tert-butyl ether), additive for non-leaded gasoline with their fast biodegradation rate and low toxicity. DMC is usually synthesized so far by oxidative carbonylation of methanol, and recently developed synthetic process is also started with methanol. Since the phase equilibria of the system, consisted of DMC and methanol or other reaction products on different temperature and pressure is necessary for the optimum separation process design and operation. However the reported phase equilibria and physical properties for DMC mixtures in the Dortmund Data Bank (DDB; thermodynamic property data bank) are quite rare. Besides, infinitely dilute properties are not found. In this work, isothermal vapor-liquid equilibria at 333.15 K for methanol+DMC binary system and mixing properties, excess molar volume and viscosity deviation at 298.15 K are directly measured and correlated. Additionally, infinitely dilute activity coefficient of methanol in the DMC solvent at three different temperatures are measured and compared with predicted values using modified UNIFAC (Dortmund).

A Development and Performance Experiment on In-rack Sprinkler Head for Rack Type Warehouse (적층식 대형창고 스프링클러헤드 개발 및 성능실험)

  • Kim, Woon-Hyung;Lee, Jun;Hong, Seong-Ho;Kim, Jong-Hoon;Yang, So-Jin
    • Journal of the Society of Disaster Information
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    • v.15 no.2
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    • pp.214-222
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    • 2019
  • Purpose: The purpose of this study is to develop a sprinkler head that can be controlled and initial suppressed by installing it in a rack-type warehouse. Method: Considering the spray radius and spray pattern, various deflectors were designed, and the spray angle, discharge characteristics and protection performance test was conducted, and these results were compared and analyzed. Results: An optimal sprinkler head was developed to protect full load, front side of a commodity with minimum water volume 115L/min. Conclusion: The developed head of K-115 and 1Bar pressure was tested with one tier storage confirming that the fire control is carried out without burning all the loadings. In addition, the vertical distance from the top of the load to the deflector shall be separated by 450mm and installed to allow sufficient discharge to the outer part of the commodity.