• Title/Summary/Keyword: Stability

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An Improved Concept of Deep Geological Disposal System Considering Arising Characteristics of Spent Fuels From Domestic Nuclear Power Plants (국내 원자력발전소에서의 사용후핵연료 발생 특성을 고려한 심층 처분시스템 개선)

  • Lee, Jongyoul;Kim, Inyoung;Choi, Heuijoo;Cho, Dongkeun
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.17 no.4
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    • pp.405-418
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    • 2019
  • Based on spent fuels characteristics from domestic nuclear power plants and a disposal scenario from the current basic plan for high-level radioactive waste management, an improved disposal system has been proposed that enhances disposal efficiency and economic effectiveness compared to the existing disposal system. For this purpose, two disposal canisters concepts were derived from the length of the spent fuel generated from the nuclear power plants. In the disposal scenario, the acceptable amount of decay heat for each disposal container was determined, taking into account the discharge and disposal times of spent fuels in accordance with the current basic plan. Based on the determined decay heat of the two types of disposal canisters and the associated disposal system, thermal stability analyses were performed to confirm their suitability to the proposed disposal system design requirement and disposal efficiency assessment. The results of this study confirm 20% reduction in the disposal area and 20% increase in disposal density for the proposed disposal system compared to the existing system. These results can be used to establish a spent fuel management policy and to design a viable commercial disposal system.

A Prediction of Saturated Hydraulic Conductivity for Compacted Bentonite Buffer in a High-level Radioactive Waste Disposal System (고준위방사성폐기물 처분시스템의 압축 벤토나이트 완충재의 포화 수리전도도 추정)

  • Park, Seunghun;Yoon, Seok;Kwon, Sangki;Kim, Geon-Young
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.18 no.2
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    • pp.133-141
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    • 2020
  • A geological repository comprises a natural barrier and an engineered barrier system. Its design components consist of canisters, buffers, backfill, and near-field rock. Among the engineered barrier system components, bentonite buffers minimize the groundwater flow from near-field rock and prevent the release of nuclide. Investigation of the hydraulic conductivity of the buffer to groundwater flow is an important factor in the performance evaluation of the stability and integrity of the engineered barrier of the repository. In this study, saturated hydraulic conductivity tests were performed using Gyeongju bentonite at various dry densities and temperatures, and a hydraulic conductivity prediction model was developed through multiple regression analysis using the 120 result sets of hydraulic conductivity. The test results showed that the hydraulic conductivity tends to decrease as the dry density increases. In addition, the hydraulic conductivity increased with increasing temperature. The multiple regression analysis results showed that the coefficient of determination (R2) of the hydraulic conductivity prediction equation was as high as 0.93. The hydraulic conductivity prediction equation presented in this study could be used for the design of engineered barrier systems.

Purification and Characterization of Carotenoprotein from the Muscle of Ascidian, Halocynthia roretzi (우렁쉥이 육으로부터 Carotenoprotein의 분리.정제 및 특성)

  • Kang, Ok-Ju;Byun, Hee-Guk;Jeon, You-Jin;Kim, Jong-Bae;Kim, Se-Kwon
    • Applied Biological Chemistry
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    • v.41 no.1
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    • pp.31-41
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    • 1998
  • A carotenoprotein from the muscle of Ascidian (Halocynthia roretzi) was purified by ion exchange chromatography and gel filtration chromatography, and analyzed molecular weight, stability of pH and heat, effect of denaturing agents, amino acids and fatty acids composition. The purified carotenoprotein had absorption maxima of 463 nm and 439 nm. The carotenoprotein had an approxmimate molecular weight of 64.4 kDa in polyacrylamide gel electrophoresis. The amino acid compositions of carotenoprotein were mainly Gly (15.39%), Asn (11.31%), Gln (10.62%) and Ser (13.35%). The major fatty acids composition of carotenoprotein were $C_{16:1(n-7)}\;(15.4%)$, $C_{22:1(n-9)}\;(14.5%)$ and $C_{20:1(n-11)}\;(11.4%)$. The monounsaturated fatty acids (45.2%) contained abundant content compared to other saturated (38.1%) and polyunsaturated (11.7%) fatty acids.

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Characteristics of ${\beta}-galactosidase$ activity in Lactobacillus plantarum from kimchi (김치에서 분리한 유산균 Lactobacillus plantarum의 ${\beta}-galactosidase$ 특성에 관한 연구)

  • Kang, Me-Seon;Rhee, Young-Hwan
    • Applied Biological Chemistry
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    • v.39 no.1
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    • pp.60-66
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    • 1996
  • To investigate a possible application of three strains of lactic acid bacteria(strain No. 49. No. 61. No. 75) from kimchi in milk fermentation industry, the optimal condition for production of intracellular ${\beta}-galactosidase$ from Lactobacillus(L.) plantarum and its enzymatic properties were examined. The preferable carbon source of the medium for strain No. 49 in production of ${\beta}-galactosidase$ was MRS broth with 1.0% lactose instead of dextrose of pH 65. for strain No. 75 with 1.0% galactose and for strain No. 61 with 3.0% lactose at pH 7.5, respectively. The maximum enzyme production from strain No. 49, No. 75 was observed after 48 hours culture at $30^{\circ}C$ in a medium containing the appropriate carbon source, from strain No. 61 after 48 hours culture at room temperature. The optimum temperature for ${\beta}-galactosidase$ activity from L. plantarum was $60^{\circ}C$ for strain No. 49, $37^{\circ}C$ for strain No. 61 and $50^{\circ}C$ for strain No. 75, respectively. The heat stability of enzyme activities for all three strains remained 90% at $45^{\circ}C$. The optimal pH was pH 6.5 and enzyme activities were most stable at pH for all three bacteria.

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Physicochemical Characteristics of Filefish and Cod Skin Collagen (말쥐치피 및 대구피 콜라겐의 물리화학적 특성)

  • Kim, Se-Kwon;Kang, Ok-Ju;Kwak, Dong-Chae
    • Applied Biological Chemistry
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    • v.36 no.3
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    • pp.163-171
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    • 1993
  • The collagens from filefish (Novoden modestus) and cod (Gadus macrocephalus Tilesius) skin were isolated and their physicochemical properties were investigated. Glutamic acid, hydroxyproline, valine and phenylalanine in the filefish skin collagen (FSC) were presented at higher levels than those of cod skin collagen (CSC), but the contents of glycine, proline and serine were contrary. The content of essential amino acids of FSC (265 residues/1000 residues) was higher than CSC (229 residues). The solubilities of both collagens were the lowest at pH 7.0, but precipitously increased at acid zone(below pH 5.0). FSC has lower viscosity than CSC. Furthermore, while the viscosities of both collagens were the lowest at pH 7.0, the viscosities of FSC and CSC were the highest at pH 4.0 and pH 2.0, respectively. The denaturation temperature of $FS(25^{\circ}C)$ was higher than $CSD\;(17^{\circ}C)$. The free hydrophobic residue contents of FSC and CSC tended to increase till $60^{\circ}C,\;and\;50^{\circ}C$ respectively, and to decrease thereafter. Hydration capacities of both collagens were the lowest at pH 7.0, and CSC had the superior hydration capacity to FSC. In addition, emulsifying and emulsifying stability of CSC was also superior to FSC.

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Purification of xylose reductase from Candida sp. BT001 and characterization of its properties (Candida sp. BT001의 xylose reductase의 정제 및 성질)

  • Hwang, In-Gyun;Lee, Sang-Hyub;Lee, Wang-Sik;Bang, Won-Gi
    • Applied Biological Chemistry
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    • v.36 no.3
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    • pp.178-183
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    • 1993
  • Xylose reductase (alditol: $NADP^+$ 1-oxidoreductase, EC 1.1.1.21) from the xylose-fermenting yeast, Candida sp. BT001, was purified via salt fractionation, ion-exchange, gel filtration and affinity chromatography, and its properties were characterized. The enzyme from the yeast was active with both NADPH and NADH as coenzyme. The xylose reductase activity with NADH was approximately 51% of that with NADPH and the specific activities of purified enzyme with NADPH and NADH were 11.78 U/mg and 6.01 U/mg, respectively. Molecular weight of the purified enzyme was 31,000 on SDS-PAGE and 61,000 on gel filtration. The Km for D-xylose, NADPH, and NADH was $94.2{\times}10^{-3}M,\;0.011{\times}10^{-3}M\;and \;0.032{\times}10^{-3}M$, respectively. The purified xylose reductase had relatively higher substrate affinity for L-arabinose than other aldoses tested. The optimal pH was 6.2 and the optimal reaction temperature was $45^{\circ}C$. The thermal stability of the enzyme was for 20 minutes at $30^{\circ}C$.

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A Study on the Konjak Mannan-hydrolyzing Enzymes from Aspergillus awamori (Aspergillus awamori 가 생산하는 konjak mannan 분해효소에 관한 연구)

  • Chang, Kyung-Jung;Lee, Su-Rae
    • Applied Biological Chemistry
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    • v.15 no.3
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    • pp.199-206
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    • 1972
  • As a study on the konjak mannan-hydrolyzing enzymes from Aspergillus awamori, the culture conditions for enzyme formation, purification and properties of the enzymes and the effect of gamma-irradiation on the enzymatic hydrolysis were investigated. The results are summarized as follows: 1) A strain of A. awamori was selected as having the highest productivity of mannanase among 81 species of molds. 2) The optimum conditions for solid culture on wheat bran were 3 days of culture period, pH 4 of spraying water and 100% addition of tap water. 3) The optimum conditions for shaking culture were 6 days of culture period, addition of 0.1% xylose plus 0.5% konjak mannan and of 0.04% peptone. 4) Konjak mannan-hydrolyzing enzymes were separated into fraction I and fraction II by ammonium sulfate fractionation and DEAE-Sephadex column chromatography. 5) Fractions I and II showed pH optima of 4, pH stability of $3.5{\sim}5$ and $3{\sim}6$ and the extent of hydrolyzing konjak mannan 9% and 50%, respectively. 6) Hydrolysis of konjak mannan by a crude enzyme preparation was partially accerelated by gamma-irradiation of substrate above 0.5 Mrad and the effect was more remarkable by irradiating in wet state than in dry state. 7) Gamma-irradiation of konjak mannan brought about the increase in reducing power and decrease in viscosity and the effect was more remarkable in wet state than in dry state.

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Studies on the Production of Fermented Feeds from Agricultural Waste Products [Part Ⅱ] -On the Production and Characteristics of Cellulase by Irpex lacteus- (농산폐기물(農産廢棄物)에서 발효사료(醱酵飼料)의 생산(生産)에 관(關)한 연구(硏究) [제2보(第二報)] -Irpex lacteus에 의(依)한 Cellulase의 생산(生産) 및 그 효소특성(酵素特性)에 관(關)하여-)

  • Lee, Ke-Ho;Koh, Jeong-Sam
    • Applied Biological Chemistry
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    • v.18 no.3
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    • pp.117-122
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    • 1975
  • In order to utilize the agricultural waste products for animal feeds, studies have been made concerning the production of cellulase of Irpex lacteus and its properties of crude enzyme, and summarized as follows. 1. At the production of cellulase, the culture of wheat bran added with rice bran was more active than any other cultures. 2. The optimum incubation time is 5 days in shaking culture. 3. The optimum condition of reaction in saccharification with CMC were obtained the following results. 1) The optimum pH was within the range of from 3.5 to 4.0 and stable within 3.0 to 6.0. 2) The optimum temperature was $40^{\circ}C$ and thermal stability was below $40^{\circ}C$. 3) The optimum reaction time was 2 hours. 4) The optimum crude enzyme concentration was 50%V/V and substrate concentration 1%.

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Beauty Food Activities of Isolated Phenolic Compounds from Ulmus pumila (유근피(Ulmus pumila)로부터 분리한 페놀성물질의 미용식품활성)

  • Kim, Kyung-Bum;Jo, Bun-Sung;Lee, Ju-Yeong;Park, Ki-Tae;An, Bong-Jeun;Lee, Sun-Ho;Cho, Young-Je
    • Journal of Applied Biological Chemistry
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    • v.55 no.4
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    • pp.207-215
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    • 2012
  • Phenolic compounds of $17.9{\pm}1.0mg/g$ were extracted from Ulmus pumila with 70% ethanol. The elastase inhibitory activity related with forming wrinkle was shown an excellent wrinkle improvement effect in 70% ethanol extracts as 55.5-69.5% at phenolic concentration of $50-200{\mu}g/mL$. The tyrosinase inhibitory activity related with skin-whitening was 24% in 70% ethanol extracts at phenolic concentration of $200{\mu}g/mL$. The astringent activity of 70% ethanol extracts was shown activity of 71% at phenolic concentration of $200{\mu}g/mL$ therefore it is judged that there is a high effect on pores reduction of the skin. The hyaluronidase inhibitory activity of U. pumila extracts was confirmed anti-inflammation effect of 80% at phenolic concentration of $50{\mu}g/mL$. Antimicrobial activity of U. pumila water extracts was shown each 8.7, 10.0, 11.1 and 11.8 mm clear zones on Propionebacterium acnes at phenolic concentration of $50-200{\mu}g/mL$. The stability of the multi-functional cosmetic (lotion) added U. pumila extracts was very stable for 28 days without changing of pH and viscosity also it's stable on temperature and sun lights. As the concentration of extracts was increased, the color of lotion was getting dark, but the sensory evaluation was high at score of 8.5.

Determination of Inorganic Phosphate in Paprika Hydroponic Solution using a Laboratory-made Automated Test Stand with Cobalt-based Electrodes (코발트전극과 자동시험장치를 이용한 파프리카 양액 내 무기인산 측정)

  • Kim, Hak-Jin;Son, Dong-Wook;Kwon, Soon-Goo;Roh, Mi-Young;Kang, Chang-Ik;Jung, Ho-Seop
    • Journal of Biosystems Engineering
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    • v.36 no.5
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    • pp.326-333
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    • 2011
  • The need for rapid on-site monitoring of hydroponic macronutrients has led to the use of ion-selective electrodes, because of their advantages over spectrophotometric methods, including simple methodology, direct measurement of analyte, sensitivity over a wide concentration range, and low cost. Stability and repeatability of response can be a concern when using multiple ion-selective electrodes to measure concentrations in a series of samples because accuracy might be limited by drifts in electrode potential. A computer-based measurement system could improve accuracy and precision because of both consistent control of sample preparation and easy calibration of sensors. Our goal was to investigate the applicability of a cobalt-based electrode used in conjunction with a laboratory-made automated test stand for quantitative determination of ${PO_4}^-$ in hydroponic solution. Six hydroponic solutions were prepared by diluting highly concentrated paprika hydroponicsolution to provide a concentration range of 1 to 300 ppm $PO_4$-P. A calibration curve relating electrode response to phosphate in paprika hydroponic solution titrated to pH 4 with 0.025M KHP was developed based on the Nikolskii-Eisenman equation with a coefficient of determination ($R^2$) of 0.94. The laboratory-made test stand consisting of three cobalt-based electrodes measured phosphate concentrations similar to those obtained with standard laboratory methods (a regression slope of 0.98 with $R^2$ = 0.80). However, the y intercept was relatively high, 30 ppm, probably due to the relatively large amount of variation present among multiple measurements of the same sample. Further studies on the high variation in EMFs obtained with cobalt electrodes during replicate measurements were required for P estimations comparable to those obtained with standard laboratory instruments.