• 제목/요약/키워드: chloride resistance

검색결과 716건 처리시간 0.02초

콘크리트의 염화물 침투저항성에 미치는 무기질 혼화재 종류의 영향 (The Effect of Mineral Admixtures' Type on the Chloride Penetration Resistance of Concrete)

  • 김영진;김동석;유재강
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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    • pp.802-805
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    • 2004
  • This study was performed to investigate the effect of mineral admixture' type and replacement ratios on the chloride penetration resistance of concrete which was immersed in the artificial chloride solution. The chloride penetration resistance was evaluated by penetration depth and chloride diffusion coefficient. As a result, all of the mineral admixtures were effective on the chloride penetration resistance of concrete compared to ordinary portland cement only.

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The Effects of Sodium Chloride on the Physiological Characteristics of Listeria monocytogenes

  • Choi, Kyoung-Hee;Yoon, Yohan
    • 한국축산식품학회지
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    • 제33권3호
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    • pp.395-402
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    • 2013
  • Sodium chloride is used to improve various properties of processed meat products, e.g., taste, preservation, water binding capacity, texture, meat batter viscosity, safety, and flavor; however, many studies have shown that sodium chloride increases the resistance of many foodborne pathogens to heat and acid. Listeria monocytogenes has been isolated from various readyto- eat (RTE) meat and dairy products formulated with sodium chloride; therefore, the objective of this paper was to review the effects of sodium chloride on the physiological characteristics of L. monocytogenes. The exposure of L. monocytogenes to sodium chloride may increase biofilm formation on foods or food contact surfaces, virulence gene transcription, invasion of Caco-2 cells, and bacteriocin production, depending on L. monocytogenes strain and serotype as well as sodium chloride concentration. When L. monocytogenes cells were exposed to sodium chloride, their resistance to UV-C irradiation and freezing temperatures increased, but sodium chloride had no effect on their resistance to gamma irradiation. The morphological properties of L. monocytogenes, especially cell elongation and filament formation, also change in response to sodium chloride. These findings indicate that sodium chloride affects various physiological responses of L. monocytogenes and thus, the effect of sodium chloride on L. monocytogenes in RTE meat and dairy products needs to be considered with respect to food safety. Moreover, further studies of microbial risk assessment should be conducted to suggest an appropriate sodium chloride concentration in animal origin foods.

해안인접지역 기초 구조물콘크리트의 내염해 성능 평가 -건축구조기준과의 성능비교- (An Evaluation on the Chloride Resistance of Concrete Footing at Coastal Area -Comparision of Performance in Korea Building Code(KBC)-)

  • 박용규;윤기원;김현우;김용로;송영찬
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2016년도 추계 학술논문 발표대회
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    • pp.148-149
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    • 2016
  • In this paper, the increase in chloride resistance of footing concrete at coastal area was evaluated by replacement of Mineral Admixture. In KBC 2009, the footing concrete's minimum specific concrete strength at coastal area is determined to 35MPa. However, this is criteria only based on the strength aspect. Thus, it is not considered to increase the chloride resistance by replacement of Mineral Admixture. According to the test results of chloride ions penetration resistance, 35MPa class concrete with OPC 100% shown inaccessible state. Low-strength (24~30MPa class) concretes with Mineral Admixture, however, presented better performances. In addition, chloride diffusion coefficient tests showed identical appearance. Therefore, the current KBC's chloride resistance criteria based on only concrete strength has to review for the reason it can cause many problems (ex. cost increases by growing concrete strength and the environmental issues by a lot of cement use).

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ClC Chloride Channels in Gram-Negative Bacteria and Its Role in the Acid Resistance Systems

  • Minjeong Kim;Nakjun Choi;Eunna Choi;Eun-Jin Lee
    • Journal of Microbiology and Biotechnology
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    • 제33권7호
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    • pp.857-863
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    • 2023
  • Pathogenic bacteria that colonize the human intestinal tract have evolved strategies to overcome acidic conditions when they pass through the gastrointestinal tract. Amino acid-mediated acid resistance systems are effective survival strategies in a stomach that is full of amino acid substrate. The amino acid antiporter, amino acid decarboxylase, and ClC chloride antiporter are all engaged in these systems, and each one plays a role in protecting against or adapting to the acidic environment. The ClC chloride antiporter, a member of the ClC channel family, eliminates negatively charged intracellular chloride ions to avoid inner membrane hyperpolarization as an electrical shunt of the acid resistance system. In this review, we will discuss the structure and function of the prokaryotic ClC chloride antiporter of amino acid-mediated acid resistance system.

고내구성콘크리트의 염해저항성에 관한 실험적 연구 (An Experimental Study on the Salt Damage Resistance of High Durable Concrete)

  • 윤재환;정재동
    • 한국건축시공학회지
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    • 제3권3호
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    • pp.73-81
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    • 2003
  • In this paper, salt damage resistance of high durable concrete was tested. High durable concrete was made by using low water cement ratio, chemical admixture called super-durable admixture and mineral admixtures such as fly-ash, ground granulated blast-furnace slag, silica fume. Two kinds of salt damage resistance test were carried out. One method is chloride ion penetration test(ASTM C1202), and the other one is depth of chloride penetration test in saline solution. Test results were as followers: 1) The depth of chloride ion penetration increased exponentially as water cement ratio was increased and time passed. 2) Super-durable admixture had little effect on the improvement of salt damage resistance of concrete. 3) Silica fume and ground granulated blast-furnace slag were effective on salt damage resistance because of pozzolanic reaction, but fly-ash had a little effect.

유지종류변화 및 표면도포에 따른 보통강도 콘크리트의 염해저항성 (Resistance to Chloride Attack of Normal Strength Concrete Depending on Spreading of Different Types of Oils)

  • 백철;이재진;황찬우;이준석;이동윤;한천구
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2017년도 추계 학술논문 발표대회
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    • pp.163-164
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    • 2017
  • The paper is to investigate the effect of spreading of various kinds of oils on resistance to chloride attack of the normal strength concrete. Resistance to chloride attack was measured for 32 weeks and six different kinds of oils ere used. Test results indicated that resistance to chloride attack was improved in order of DSP, BD, ERBD and ERCO compared with that of Plain mixture due to filling effect of capillary pore by the use of oil.

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석탄가스화 용융 슬래그 치환 콘크리트의 염화이온 침투 저항성 검토 (Evaluation of Chloride Ion Penetration Resistance of Coal Gasification Slag Replaced Concrete)

  • 조현서;김민혁;이건철
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2019년도 추계 학술논문 발표대회
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    • pp.166-167
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    • 2019
  • In this study, to test the performance of concrete used as a concrete admixture as a recycling method of CGS, gypsum was mixed and the chloride ion penetration resistance test of CGS and BFS substituted concrete was conducted. As a result, it was found that without gypsum type test specimen, the CGS sustituted test specimens had lower chloride ion penetration resistance than the BFS substituted specimens. When gypsum was added, it was confirmed that the chloride ion penetration resistance was poor regardless of the type of admixture. In addition, it was confirmed that both admixtures were less resistant to chloride ion penetration than OPC, regardless of the presence of gypsum. However, considering the uneven quality variation of coal, which greatly affects the quality of CGS, further research is needed.

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박테리아 흡착 팽창질석을 혼입한 모르타르의 염소이온 침투 저항성 (Chloride Ion Penetration Resistance of Mortars including Expanded Vermiculite Immobilizing Bacteria)

  • 정승배;양근혁
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2017년도 추계 학술논문 발표대회
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    • pp.151-152
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    • 2017
  • This tests examined the effectiveness of bacteria slime on the chloride ion penetration resistance of cement mortar. Test results exhibited that the chloride ion penetration depth of mortars including 5% expanded vermiculite immobilizing bacteria was 17% smaller than that of the control mortar without expanded vermiculite.

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고로슬래그 미분말 콘크리트의 염화물이온 확산모델 (A Chloride Ion Diffusion Model in Blast Furnace Slag Concrete)

  • 이석원;박상순;송하원;변근주
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2000년도 가을 학술발표회논문집(I)
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    • pp.467-472
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    • 2000
  • It is known that chloride ion in concrete destroys the passive film of reinforcement inside concrete and accelerates corrosion which is the most influencing factor to durability of concrete structures. In this thesis, a chloride ion diffusion model for blast furnace slag(BFS) concrete, which has better resistance to both damage due to salt and chloride ion penetration than ordinary portland cement concrete, is proposed by modifying existing model of normal concrete. Proposed model is verified by comparing diffusion analysis results with both results by indoor chloride penetration test for specimens and field test results for actual RC bridge pier. Also, the optimum resistance condition to chloride penetration is obtained according to degrees of fineness and replacement ratios of BFS concrete. As a result, resistance to chloride ion penetration for BFS concrete is more affected by replacement ratio than degree of fineness.

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Manufacture and Properties of Inorganic Chemical Treated Wood by Introducing of Fluorides

  • Kim, Soung-Joon;Lee, Jong-Shin
    • Journal of the Korean Wood Science and Technology
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    • 제36권2호
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    • pp.73-78
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    • 2008
  • Inorganic chemical treated wood was prepared by impregnation of calcium or magnesium chloride ($CaCl_2$ or $MgCl_2$) solution and immersion in saturated solution of ammonium fluoride ($NH_4F$) as a reactant in order to make an introduction of a refractory fluorides with fungicidal and insecticidal effects in wood. The weight percent gains (WPGs) were increased with increase in concentration of calcium chloride or magnesium chloride solution, and were higher in treatment with calcium chloride than with magnesium chloride. Inorganic substances were produced mainly in the lumina of tracheides. These substances were proved to be the calcium fluoride or magnesium fluoride by the energy dispersive X-ray analyzer in conjunction with a scanning electron microscope (SEM-EDX). The treated wood showed good decay resistance because the weight losses were hardly occurred by the test fungi such as Tyromyces palustris and Trametes versicolor. The fire resistance effect was superior to the treated wood compared with that of the untreated wood.