• Title/Summary/Keyword: Limited of stability

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Chemical Stability of Conductive Ceramic Anodes in LiCl-Li2O Molten Salt for Electrolytic Reduction in Pyroprocessing

  • Kim, Sung-Wook;Kang, Hyun Woo;Jeon, Min Ku;Lee, Sang-Kwon;Choi, Eun-Young;Park, Wooshin;Hong, Sun-Seok;Oh, Seung-Chul;Hur, Jin-Mok
    • Nuclear Engineering and Technology
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    • v.48 no.4
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    • pp.997-1001
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    • 2016
  • Conductive ceramics are being developed to replace current Pt anodes in the electrolytic reduction of spent oxide fuels in pyroprocessing. While several conductive ceramics have shown promising electrochemical properties in small-scale experiments, their long-term stabilities have not yet been investigated. In this study, the chemical stability of conductive $La_{0.33}Sr_{0.67}MnO_3$ in $LiCl-Li_2O$ molten salt at $650^{\circ}C$ was investigated to examine its feasibility as an anode material. Dissolution of Sr at the anode surface led to structural collapse, thereby indicating that the lifetime of the $La_{0.33}Sr_{0.67}MnO_3$ anode is limited. The dissolution rate of Sr is likely to be influenced by the local environment around Sr in the perovskite framework.

Field Applicability Assessment of Controlled Low Strength Material for Sewer Pipe using Excavated Soil (굴착토를 활용한 유동화 채움재의 현장 적용성 평가)

  • Kim, Young-Wook;Lee, Bong-Chun;Jung, Sang-Hwa
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.7 no.4
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    • pp.349-357
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    • 2019
  • Controlled low strength material(CLSM) has been developed using variety of material such as excavated soil, industrial by-product and industrial waste. But theses research limited at laboratory test and failed at commercialization. So in this paper evaluates CLSM used excavated soil characteristics such as flowability, bleeding rate, early strength for following process and 28day strength for re-excavatability. Also, various mix proportion of CLSM by water-binder ratio and soil-binder ratio were evaluated in laboratory. And derive the optimized CLSM mix proportion for using at field application test by movable batch plant. After applying CLSM at trench, evaluate core sample strength and excavatability by shovel, pickax and excavator for verify re-excavation. Furthermore, measure the level change after casting CLSM to inspect subsidence stability. As results of these assessments, not only confirmed the characteristics of CLSM at field but the fillability around pipe and subsidence stability.

Review on Membrane Materials to Improve Plasticization Resistance for Gas Separations (가소화 저항 향상을 위한 기체분리막 소재 개발 동향)

  • Jo, Jin Hui;Chi, Won Seok
    • Membrane Journal
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    • v.30 no.6
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    • pp.385-394
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    • 2020
  • In the gas separation process, the separation membranes have to not only show high gas transport and selectivity but also exhibit exceptional stability at high temperature and pressure. However, when the polymeric membranes (particularly, glassy polymers) are exposed to the condensable gases (i.e., CO2, H2S, hydrocarbon, etc.), the polymer chains are prone to swell, leading to low stability. As a result, the plasticization behavior reduces the gas selectivity in the separation of mixture gases at high pressures and thus results in limited applications to the separation processes. To address these issues, many strategies have been studied such as thermal treatment, polymer blending, thermally rearrangement, mixed-matrix membranes, cross-linking, etc. In this review, we will understand the plasticization behavior and suggest potential methods based on the previously reported studies.

Three-Dimensional Limit Equilibrium Stability Analysis of Spile-Reinforced Shallow Tunnel

    • Geotechnical Engineering
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    • v.13 no.3
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    • pp.101-122
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    • 1997
  • A spiting reinforcement system is composed of a series of radially installed reinforcing spites along the perimeter of the tunnel opening ahead of excavation. The reinforcing spill network is extended into the in-situ soil mass both radially and longitudinally The sailing reinforcement system has been successfully used for the construction of underground openings to reinforce weak rock formations on several occasions. The application of this spiting reinforcement system is currently extended to soft ground tunneling in limited occasions because of lack of reliable analysis and design methods. A method of threetimensional limit equilibrium stability analysis of the smile-reinforced shallow tunnel in soft ground is presented. The shape of the potential failure wedge for the case of smile-reinforced shallow tunnel is assumed on the basis of the results of three dimensional finite element analyses. A criterion to differentiate the spill-reinforced shallow tunnel from the smile-reinforced deep tunnel is also formulated, where the tunnel depth, soil type, geometry of the tunnel and reinforcing spites, together with soil arching effects, are considered. To examine the suitability of the proposed method of threedimensional stability analysis in practice, overall stability of the spill-reinforced shallow tunnel at facing is evaluated, and the predicted safety factors are compared with results from twotimensional analyses. Using the proposed method of threetimensional limit equilibrium stability analysis of the smile-reinforced shallow tunnel in soft ground, a parametric study is also made to investigate the effects of various design parameters such as tunnel depth, smile length and wadial spill spacing. With slight modifications the analytical method of threeiimensional stability analysis proposed may also be extended for the analysis and design of steel pipe reinforced multi -step grouting technique frequently used as a supplementary reinforcing method in soft ground tunnel construction.

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Catalytic Properties of Monomeric Species of Brain Pyridoxine-5'-phosphate Oxidase

  • Kwon, Oh-Shin;Choi, Soo-Young
    • BMB Reports
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    • v.34 no.1
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    • pp.21-27
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    • 2001
  • The structural stability of brain pyrydoxine-5'-phosphate (PNP) oxidase and the catalytic properties of the monomeric species were investigated. The unfolding of brain pyridoxine-5'-phosphate (PNP) oxidase by guanidine hydrochloride (GuHCl) was monitored by means of fluorescence and circular dichroism spectroscopy Reversible dissociation of the dimeric enzyme into subunits was attained by the addition of 2 M GuHCl. The perturbation of the secondary structure under the denaturation condition resulted in the release of the cofactor FMN. Separation of the processes of refolding and reassociation of the monomeric species was achieved by the immobilization method. Dimeric PNP oxidase was immobilized by the covalent attachment to Affi-gel 15 without any significant lass of its catalytic activity. Matrix-bound monomeric species were obtained from the reversible refolding processes. The matrix bound-monomer was found to be catalytically active, possessing only a slightly decreased specific activity when compared to the refolded dimeric enzyme. In addition, limited chymotrypsin digestion of the oxidase yields two fragments of 12 and 161 kDa with a concomitant increase of catalytic activity The catalytically active fragment was isolated by ion exchange chromatography and analyzed for association of two subunits using the FPLC gel filtration analysis. The retention time indicated that the catalytic fragment of 16 kDa behaves as a compact monomer. Taken together, these results are consistent with the hypothesis that the native quaternary structure of PNP oxidase is not a prerequisite for catalytic function, but it could play a role in the regulation.

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An Empirical Study of Determinants of Customer Satisfaction of Banking Sector: Evidence from Bangladesh

  • GAZI, Md. Abu Issa;RAHAMAN, Md. Atikur;HOSSAIN, G.M. Anwar;ALI, Md. Julfikar;MAMOON, ZahidurRahman
    • The Journal of Asian Finance, Economics and Business
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    • v.8 no.2
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    • pp.497-503
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    • 2021
  • The aim of this study is to determine the factors that affect customer satisfaction in the banking sector of Bangladesh because the economic growth and stability of a country depends on the soundness of its banking sector. The study tries to investigate and assess the quality of service on customer satisfaction in the banking sector. As a sample, data were collected from 382 respondents who were customers of 32 selected commercial banks of Bangladesh. A pre-structured questionnaire was used to collect the required data and information. OLS regression model and descriptive statistical tools were used to analyze data. The results of this study reveal that the quality of service (e.g., tangibility, reliability, and empathy) has a statistically significant impact on customer satisfaction. The results also show that there is a positive correlation between the customer satisfaction and service quality dimensions in the banking sector of Bangladesh. The present study finds that in the domestic banking industry the service quality dimensions (i.e., tangibility, reliability, and empathy) have significant positive impact on customer satisfaction. The findings of the present study suggest that Bank Supervisory Authority, Central Bank of Bangladesh, and Bank Management should give special emphasis to ensure maximum satisfaction of banks' customers.

A Examination on Stability of Dam using 3D Laser Scanning System (3D Laser Scanning을 이용한 댐체의 안정성 검토)

  • Lee, Jae-One;Shon, Ho-Woong;Yun, Bu-Yeol
    • Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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    • 2007.04a
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    • pp.451-454
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    • 2007
  • There is an inseparable relation between human race and engineering work. As world developed into highly industrialized society, a diversity of large structures is being built up correspondently to limited topographical circumstance. Though large structures are national establishments which provide us with convenience of life, there are some disastrous possibilities which were never predicted such as ground subsidence and degradation. It is very difficult to analyze the volume of total metamorphosis with the relative displacement measurement system which is now used and it is impossible to know whether there is structural metamorphosis within a permissible range of design or not. In this research with an object of 13-year-old earthen dam, through generating point-cloud which has 3D spatial coordinates(x, y, z) of this dam by means of 3D Laser Scanning, we can get real configuration data of slanting surface of this dam with this method of getting a number of 3D spatial coordinates(x, y, z). It gives 3D spatial model to us and we can get various information of this dam such as the distance of slanting surface of dam, dimensions and cubic volume. It can be made full use of as important source material of reinforcement and maintenance works to detect previously the bulging of the dam through this research.

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A Study on Gain of Feedforward Compensator about Source Voltage Variation of Three-phase Series Active Power Filter (3상 직렬형 능동필터의 입력전압변동에 대한 전향보상이득에 관한 연구)

  • Kwon H.N.;Nam N.J.;Kang B.H.;Choe G.H.;Han S.W.
    • Proceedings of the KIPE Conference
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    • 2001.12a
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    • pp.97-101
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    • 2001
  • Recently, as the development of industry, the nonlinear load becomes increased. Because of nonlinear load, the variation of source voltage is generated by the impedace of source side flowed harmonic currents. For blocking harmonic currents by nonlinear load, a series active power filter operates blocking resistance of harmonic currents. The value of blocking resistance shows ideal compensating characteristic out of theoretically infinite value. But the blocking resistance is limited by the problem of the system stability and the capacity of inverter. In this paper, the value of optimum blocking resistance is found by a simulation in the applied system. In the case of unbalanced source voltages, each relation of the blocking resistance is shown. It is proved that blocking resistance of series active power filter relates to a passive filter.

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Preferential face coating of knitted PET fabrics via UV curing for water- and oil-repellent finish (자외선 경화에 의한 PET 니트직물의 편면 발수발유 가공)

  • Jeong, Yong-Kyun;Jeong, Yongjin;Jang, Jinho
    • Textile Coloration and Finishing
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    • v.17 no.6 s.85
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    • pp.27-35
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    • 2005
  • Conventional pad- dry-cure(thermo-fixation) process usually produces functional performance on both sides of a fabric. UV curing technique was applied to impart water- and oil-repellent finish effective only on the face of a PET knitted fabric. The preferential one-side coating, by virtue of the limited penetration of UV light, was achieved by W curing after padding of a fluorocarbon agent without special coating or printing equipments. The difference in the functional property of face and back sides was examined by measuring water and oil repellency at each side of the treated fabric. The influence of pre/post-irradiation dose and agent concentration on the performance of the finished fabrics were investigated. While increase in both resin concentration and post-irradiation did not have significant effect on the finish, UV pre-irradiation of PET fabrics caused remarkable influence presumably due to appropriate surface modification of PET fabrics required for facile wetting of the resin. The dimensional stability and color change of the UV cured fabrics measured by FAST and reflectance spectrophotometry showed significantly decreased color difference and increased percent extension compared with the samples pre-irradiated without agent application.

Study on Effects of Anti-oxidant and Viscoelastic on Emulsion by the Extract of Astragalus membranaceus (황기(黃芪)추출물의 항산화 효능과 에멀션 점탄성도에 미치는 영향에 관한 연구)

  • Park, Chan-Ik
    • The Korea Journal of Herbology
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    • v.27 no.2
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    • pp.93-97
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    • 2012
  • Objectives : The Astragalus membranaceus has been used to diuretic, tonic, anti-viral, anti-oxidant activities in oriental herb medicine, and in each experiment, proved in this effects. Root of A. membranaceus includes according to flavonoid, saponin, polysaccharide, thus it has been studied for anti-oxidant, anti-inflammatory, anti-cancer activities. However, previous researches have been performed with being limited mainly to food industry. The present study was conducted anti-oxidative activity of A. membranaceus extracts. In addition, The objective of the present study was to determine the possibility for the application of emulsions in the development of A. membranaceus for cosmetics. Methods : In this study, aimed SOD like activity of A. membranaceus extract, effects of A. membranaceus extract on viscoelastic properties of emulsion was measured using rheometer. Results : In the results, 1, 3-butylene glycol extract of A. membranaceus efficiently reduce the active oxygen, SOD like activity of more than 40% decrement depend on concentration. And A. membranaceus extract increase the modulus of elasticity of emulsion, therefore A. membranaceus extract have not influence on stability loss. As such, the A. membranaceus extracts will remain stable when applied to emulsions or skin products. Conclusions : In consequence of this study, A. membranaceus extract can be effectively used in cosmetic emulsions when the relation between natural product extracts and formulation of cosmetics is elucidated. It is highly recommended that rheology be applied to determine the optimal extract concentration for cosmetic formulations.