• Title, Summary, Keyword: alkali

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Study on Image - Transfer Process in color Photography (천연색 사진에서 전사방법에 관한 고찰)

  • 최정병
    • Journal of the Korean Printing Society
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    • v.2 no.1
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    • pp.23-33
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    • 1984
  • Color providing compounds on image transfer process in color photo graphy was studied with polaroid and Kodak products as a model. These compounds was inititally alkali-mobile or alkali-immobile. Alkali-mobile compunds require imagewise immobilifation in the process or alkali immoble compounds require mobilization by the cleavage reaction. As a result of studies, the polaroid products was showed alkali mobile and Kodak product represented alkali immobile.

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Investigation of Alkali-Aggregate Reaction of Abroad Aggregates (Using Area of KOREA Cement) (첨가 이온종류에 따른 외국 골재의 알카리.골재 반응성 조사연구 (한국 시멘트 사용 지역 중심))

  • 현석훈;엄태형
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.111-117
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    • 1995
  • The alkali-aggregate reaction is a reaction between the alkali metals in the pore water of a concrete and an unstable mineral of the aggregate. There are three types of alkali-aggregate reation which causes deterioration of concrete, such as alkali-silicate reation, alkali-carbonate reaction and alkali-silica reation. Deterioration due to alkali-silica reation is more comon than that due to either the alkali-silicate or alkali-carbonate reaction. The alkali-silica reation is a reaction between the hydroxyl ions in the pore water of a concrete and silica which exists in signigicant quantities in the aggregate. In this PAPER, Alkali-aggregate reactions of mortar made with various abroad aggregate were investigated using XRD, microscope, chemical and physical tests. In additions, the effects of the texture of aggregate, Na, K, CI ion concentrations added to the mortar, on these reactions were studied.

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A Experimental Study on the Alkali-Silica Reaction of Crushed Stones (Part 2 : The Influence of the Alkali Content and the Kind of Added Alkali to the Alkali-Silica Reaction) (쇄석 골재의 알칼리-실리카 반응에 관한 실험적 연구( 제 2보 : 첨가알칼리량 및 종류가 알칼리-실리카 반응에 미치는 영향))

  • 이영수;윤재환;정재동;노재호;이양수;조일호
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.108-112
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    • 1993
  • The term Alkali-Silica Reaction (ASR) is used to describe a reaction between certain siliceous aggregates and hydroxyl ions present in the pore fluid of a concrete. The ASR is affected by the content of alkali, the particle size and the content of reactive aggregate, water-cement ratio, humidity, temperature and so on. In this paper, the fluence of alkali content and kind of added alkali to the ASR was studied. As a result, the more the content of alkali was increased, the more the mortar-bar was expand and the expansion of mortar-bar was showed differently with the added alkali kinds, The reaction products by ASR were observed by SEM(Scanning Electron Microscope) and analyzed by EDXA(Energy Dispersive X-ray Analysis) also and showed a gel composed of alkali(Na+, K+), silica and calcium.

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Some Interference Studies in Alkali and Alkali-Earth Metal Determination of Silicates by Atomic Absorption Spetrophotometry (원자흡광분석법에 의한 규산염중의 알칼리 및 알칼리토금속 정량시의 간섭에 대하여)

  • 박순자
    • Journal of the Korean Ceramic Society
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    • v.13 no.4
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    • pp.15-19
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    • 1976
  • Mutual interferences of alkali and alkali-earth metals in atomic absorption were examined. For determination of Na or K interfering elements increase the absorbancy, and for Ca or Mg decrease. Since influences of coexisting elements become nearly constant by addition of large amount of same coexisting element, could be use mixed standard solution for alkali or alkali-earth metal determination in the presence of other alkali and alkali-earth metals. The metals can be readily incorporated into scheme of rapid silicate analysis. Precision and accuracy are good.

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Influence of Potassium on the Cement Clinker Formation : II. Factors of Unstable Alkali Formation (시멘트 클린커 생성과정에 미치는 Potassium의 영향 II. 불안정 알칼리 생성 인자)

  • 서일영;최상홀
    • Journal of the Korean Ceramic Society
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    • v.22 no.2
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    • pp.25-32
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    • 1985
  • Effect of alkali $SO_3$ and $C_2S$ content and cooling condition of clinker on the formation of unstable alkali and cooling condition of clinker on the formation of unstable alkali was investigated. As a result alkali and $SO_3$ content of clinker were the main factors of unstable alkali formation and equation (7) in which the two factors were the variables showed a good agreement with the observed results. Water soluble alkali content of sulphate was decreased with increase of $C_2S$ content of clinker resulted by the increase of solid solution rate of alkali to clinker minerals. But change of unsatble alkali content accordint to the increase of $C_2S$ content was slight. A increasing tendency of ignition loss of clinker with increase of unstable alkali content was found.

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Effect of Color Developing by Alkali and Heating of Cotton Fabrics Dyed with Persimmon Extract (알칼리와 열처리에 의한 면직물의 감즙염색 발색효과)

  • Kim, Ok-Soo;Jang, Jeong-Dae
    • Fashion & Textile Research Journal
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    • v.13 no.6
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    • pp.972-982
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    • 2011
  • The purpose of this study is to improve the method of color developing with alkali solution as a promotor of color developing for feasible use. Cotton fabric was dyed with persimmon extract ranged with 0~3% alkali component with 5 types of strong to mild alkali solution. Heat treatment for color developing was applied to fabric dyed with persimmon extract and alkali mixing solution. Tests were carried out to analyze the change of surface color, ${\Delta},Ea^*b^*$, and water repellent of the dyed cotton fabric. The alkali mixing sample showed higher ${\Delta},Ea^*b^*$ value than control one without alkali mixing on the base of dyed fabric due to high color developing by alkali in the initial step of dyeing process. As alkali concentration increased, deeper dark color appeared on the fabric. The fabric color was changed to more dark in the application of sodium hydroxide, sodium carbonate, potassium carbonate in the initial step of dyeing process but color was not changed by increased heating time. However, the fabric showed a slight dark color with sodium acetate and more color change than that of the fabric dyed with persimmon extract without alkali. Therefore, sodium acetate seemed to a suitable promotor for color developing in persimmon extract dyeing. Property of water repellent was showed after color developing by heating with low concentration of alkali treatment.

Changes in Amylose Content and Alkali Digestibility Value of Rice Grain During Ripening Period (성숙기간중 미입내 Amylose함량과 Alkali 붕괴성의 변이)

  • 음문회;박순직;서학수
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.24 no.3
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    • pp.1-6
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    • 1979
  • Amylose content and alkali digestibility value of rice grain were tested from 10days after flowering up to maturity. Both amylooe content and alkali digestibility value showed slightly lower at earliest stage, but they reached maximum value by 20 days after flowering, and then they maintained the value until maturity. Both amylose content and alkali digestibility value showed negative correlations to air temperature, though they were not significant statistically except in case of amylose content and maximum temperature, which showed significant correlation in some year.

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Effect of Cement Alkali Content on ASR Expansibility by the Test Method of ASTM C 1260 (ASTM C 1260 실험방법에 의한 시멘트 알칼리 함량이 ASR 팽창성에 미치는 영향)

  • Jeon, Sung Il;Son, Hyeon Jang;Kwon, Soo Ahn;Yun, Kyung Ku
    • International Journal of Highway Engineering
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    • v.14 no.6
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    • pp.37-43
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    • 2012
  • PURPOSES : This study is to evaluate the feasibility of setting the standard of cement alkali content by using ASTM C 1260(accelerated mortar bar test) METHODS : This study analyzes the ASR(alkali silica reaction) expansion of cement mortar bar based on the changes in the aggregate type(fine, coarse), cement type(ordinary, low alkali), and replacement contents of fly ash. ASR tests were conducted according to ASTM C 1260. RESULTS : In this test results, There is no big difference in the ASR expansion between ordinary cement and low alkali cement. From this test results, it was found that the variation of cement alkali content did not have a effect on ASR expansion because mortar bar was placed in a container with sufficient alkali aqueous solution at high temperature during the test process of ASTM C 1260. CONCLUSIONS : It is evidently clear that the alkali content of cement have a effect on ASR. But ASTM C 1260 is difficult to assess this effect.

Utilization of Domestic Small Timbers -Shrinkage and Swelling of Alkali-Treated Woods- (간벌재 및 소경재의 이용개발에 관한 연구 -알칼리 처리 목재의 수축팽윤성-)

  • 황원중;김남훈
    • Journal of Korea Foresty Energy
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    • v.18 no.2
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    • pp.70-77
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    • 1999
  • The behaviors of alkali swelling in four major Korean woods were examined as a function of concentration cf alkali solution. Density of alkali-treated woods increased highly with increasing alkali concentration in both softwoods and hardwoods. Wood samples swelled in dimension during alkali swelling, and thereafter they shrank highly by water washing and air drying. The air-dried wood samples after alkali treatment showed almost isotropic shrinkage in tangential and radial direction.

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Introduction of alkali soaking and microwave drying processes to improve agar quality of Gracilaria verrucosa

  • Kim, Yong-Woon;Shin, Hyun-Jae
    • Korean Journal of Chemical Engineering
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    • v.34 no.12
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    • pp.3163-3169
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    • 2017
  • Gracilaria species produce agars with low quality due to their high sulfate concentrations. For this reason, the gel properties of many Gracilaria agars must be improved by appropriate processes. In this study, we developed an improved agar extraction process for Gracilaria verrucosa by alkali soaking extraction and microwave thawing and drying. Variables such as the seaweed to alkali volume ratio, extraction time, and alkali concentration were adjusted to optimize the yield and agar quality. The yield of the agar was maximized ($34.5{\pm}0.6%$) using 3% alkali concentration; the lowest yield ($17.0{\pm}1.7%$) was obtained with 1% alkali concentration. Agar gel strengths ranged from $462.0{\pm}7$ to $627.3{\pm}11g{\cdot}cm^{-2}$. We have developed a process for quickly producing an agar gel through thawing and drying using microwave radiation. This study shows the possibility of producing a high-value agar using alkali soaking extraction methods for nonedible G. verrucosa.