• Title/Summary/Keyword: Optimum Curing time

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Soil stabilization by ground bottom ash and red mud

  • Kim, Youngsang;Dang, My Quoc;Do, Tan Manh;Lee, Joon Kyu
    • Geomechanics and Engineering
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    • v.16 no.1
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    • pp.105-112
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    • 2018
  • This paper presents results of a compressive investigation conducted on weathered soil stabilized with ground bottom ash (GBA) and red mud (RM). The effects of water/binder ratio, RM/GBA ratio, chemical activator (NaOH and $Na_2SiO_3$) and curing time on unconfined compressive strength of stabilized soils were examined. The results show that the water/binder ratio of 1.2 is optimum ratio at which the stabilized soils have the maximum compressive strength. For 28 days of curing, the compressive strength of soils stabilized with alkali-activated GBA and RM varies between 1.5 MPa and 4.1 MPa. The addition of GBA, RM and chemical activators enhanced strength development and the rate of strength improvement was more significant at the later age than at the early age. The potential environmental impacts of stabilized soils were also assessed. The chemical property changes of leachate from stabilized soils were analyzed in terms of pH and concentrations of hazardous elements. The observation revealed that the soil mixture with ground bottom ash and red mud proved environmentally safe.

Effect of Resorcinol as Free Formaldehyde Scavenger for Fabric Finished with Urea-formaldehyde Precondensate. (Urea-Formaldehyde 수지가공포에 있어 Resorcinol의 유리 Formaldehyde 포착효과)

  • Kang, In-Sook;Kim, Sung-Reon
    • Textile Coloration and Finishing
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    • v.9 no.2
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    • pp.41-49
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    • 1997
  • To control free formaldehyde release from fabric finished with N-methylol compounds, resin finished cotton fabric was treated with resorcinol solution, dried and cured. Factors affecting to control formaldehyde release have been investigated. It was shown that the aftertreatment with resorcinol greatly suppressed the free formaldehyde release. Up to concentration of about 5% of resorcinol, the concentration of resorcinol effected on the control of free and evolved formaldehyde. And at high concentration of resorcinol, however, the concentration became rather insensitive to contol formaldehyde release. Addition of some salt catalysts such as ammonium chloride, zinc nitrate, sodium acetate and ammonium acetate, was effective in decreasing formaldehyde release. Considering the effect on the control of formaldehyde and crease recovery, ammonium acetate was concidered to be the best catalyst. It was observed that the optimum curing temperature for the resorcinol treatment was about 15$0^{\circ}C$, and that the curing time did not affected formaldehyde release over three minutes. Although the treatment of resorcinol had a little adverse effect on crease recovery of resin finished fabric, this effect could be negligible.

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A Study on the Fashion Accessary Product Development by Use of Korean Traditional Hanji (Part I) -Physical Properties of the Korean Traditional Paper(Hanji) Treated with Silcone resin- (전통한지를 활용한 패션 악세서리 상품개발 (제1보) -실리콘 수지로 처리된 한지의 물성변화-)

  • Kim Eun-Ah;Ryu Hyo-Seon;Kim Yong-Sook
    • Journal of the Korean Society of Clothing and Textiles
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    • v.30 no.3 s.151
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    • pp.481-486
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    • 2006
  • There are attempts to utilize Hanji for apparel material, but, the reason that the strength and durability of Hanji decrease to a great extent in the wet condition, restricts the usability of Hanji. In order to improve the resistance against water, Hanji was treated with silicone type water repellent agents. The treatment was carried out by conventional pad-dry-cure method. The optimum treatment condition was obtained by varying the concentration of repellent agent, curing temperature and time. Water repellency was tested by spray rating method. Wet and dry tensile strength, tearing resistance and abrasion resistance were examined after the treatment. Flexural stiffness and wrinkle recovery angles of hanji were also measured. In result, the optimum condition of treatment was at resin concentration of 40g/l, catalyst concentration of 20g/l(half of resin concentration), curing temperature of 160$^{circ}C$, curing time of 120 sec. Flexural stiffness of Hanji was hardly increased and wrinkle recovery angle of Hanji was improved a little by resin treatment. After the treatment, in dry condition, tensile strength and tearing resistance were little changed but abrasion resistance was improved. In wet condition, tensile strength, tearing strength and abrasion resistance were improved.

Effect of Modification of SeO2/Acrylamide Ratios on Diffraction Efficiencies in PVA/AA Photopolymer Films

  • Kim, Dae-Heum;Lim, Ji-Yun;Nam, Seung-Woong;Chung, Dae-Won
    • Journal of the Optical Society of Korea
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    • v.11 no.4
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    • pp.183-191
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    • 2007
  • The highest diffraction efficiency(DE) value after illumination and post-curing of photopolymer films were obtained at the $SeO_2$/Acrylamide(AA) Ratios of AA 3.0 g, $SeO_2$ 1.0g and the DE's were stable values of over 90%. By the addition of $SeO_2$, the maximum DE at the initial stage of illumination was reached at 300 seconds, which suggests $SeO_2$ slows down the photopolymerization of AA, which enhances the maximum DE value by giving more migration time. DE variation curve for the optimum composition during extended-time illumination of 9,000 seconds resembles a sine curve due to the combination of the monomer diffusion and the photopolymerization, and the photopolymer film expanded by about 8% after photopolymerization due to monomer migration.

Reinforcement of Polychloroprene by means of Silia and Glass Fiber (Silica와 Glass Fiber에 의한 Polychloroprene의 보강(補强))

  • Yoo, Chong-Sun;Paik, Nam-Chul
    • Elastomers and Composites
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    • v.23 no.3
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    • pp.223-229
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    • 1988
  • The effect of triazine thiol derivative on the physical properties of silica-polychloroprene(CR) composites and glass fiber(MGF)-CR composites was investigated. Optimum cure time of the MGF composites filled with 2-dibuthylamino-4, 6-dithiol-s-triazine(DBT) was the fastest one, while maximum torque was the best in case of the silica composites filled with s-triazine-2,4,6-trithiol(TAT) on the Oscillating Disk Rheometer(ODR) test. Stress-strain curves of the composites showed that the physical properties such as 100% modulus, 300% modulus, tensile strength of the silica composites filled with DBT was very satisfactory and the silica composites filled with TAT was higher density of crosslinking than other crosslinked elastomer. In aging properties, elastomer filled DBT and TAT were progress post-curing reaction with increasing of aging time and it have been improved the tensile strength and crosslinking density.

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Fundamental Properties of Mortar and Concrete Using High Calcium Fly Ash (고칼슘 플라이애시를 활용한 모르타르 및 콘크리트의 기초적 물성)

  • Lee, Min-Hi
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.4 no.3
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    • pp.284-291
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    • 2016
  • To evaluate the properties of inorganic composites using a great quantity of high-calcium fly ash generated in combined heat and power plants, high-calcium fly ash and F-class fly ash commonly used as concrete admixtures were substituted with binding materials to examine changes of fluidity and compressive strength depending on the substitution ratio for each curing temperature. According to the experimental result, CFA-mixed mortar showed a tendency to reduce its flow unlike FFA-mixed mortar as the substitution ratio was increased, but its flow loss showed smaller than FFA as time passed. As a result of examining compressive strength depending on mixing FA, FFA-mixed mortar had an optimum range within 50% when curing at ambient temperature, but it was found that the compressive strength is reduced when mixing CFA. When curing at high temperature, FFA did not relatively have a great effect on the substitution ratio, but CFA could expect a strength enhancement effect compared with 100% of OPC when using within 25% of binding materials.

A Study on Extraction Condition of Co-PET from PET/Co-PET Sea-Island Type Microfiber Fabric (PET/Co-PET해도사 직물의 Co-PET추출 조건에 관한 연구)

  • 박명수;윤종호;조대현
    • Textile Coloration and Finishing
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    • v.13 no.2
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    • pp.120-127
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    • 2001
  • In order to make a microfiber fabric with PET/Co-PET Sea-Island Type microfiber, the optimum condition of extraction and elimination of Co-PET from the mocrofiber was examined. At the same time, the physical property change of the fabric with respect to the change of the relative amount of the Co-PET in the microfiber was also examined to provide a directly applicable data set to the industry. The sample fabric used was warp 75/36(DTY) and weft 0.05d(PET/Co-PET, Sea Island Type Microfiber) twill fabric of 36 separated yarns+40/24(high shrinking yarn) with 130/48 ITY. The data set was made at various NaOH concentrations and steam temperatures with time as a main variable. The physical properties examined were the tensile properties. The results obtained were the tensile. The results obtained were 1. For a proper extraction of Co-PET (13.5%)from the microfiber with wet curing, it takes more than 5 min. in 8 and 12% of NaOH solutions but it takes only 3 min. in 18% of NaOH solution at 12$0^{\circ}C$. 2. For a proper extraction of Co-PET (13.5%) from the microfiber with wet curing, ti takes 3~5min. in 12 and 14% of NaOH solution and it takes less than 3 min. in 18% of NaOH solution at $130^\circ{C}$. 3. The increasing ratio of WT increased with increasing NaOH concentrations and the equilibrium point reached was 3 min. at $120^\circ{C}$. 4. The WT increasing ratio was greater in 14 and 18% NaOH solutions than in 8 and 12% of NaOH solutions at $130^\circ{C}$5. The RT ratio changes at $120^\circ{C}$ in 8 and 12% of NaOH solutions were indifferent from that at $130^\circ{C}$ in 12% of NaOH solution. However, the RT was apparently decreased with increasing NaOH concentration.

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A Study on Extraction Condition of Co-PET from PET/Co-PET Sea-Island Type Microfiber Fabric (PET/Co-PET 해도사 직물의 Co-PET 추출 조건에 관한 연구)

  • Park, Myeong Su;Yun, Jong Ho;Jo, Dae Hyeon
    • Textile Coloration and Finishing
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    • v.13 no.2
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    • pp.34-34
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    • 2001
  • In order to make a microfiber fabric with PET/Co-PET Sea-Island Type microfiber, the optimum condition of extraction and elimination of Co-PET from the microfiber was examined. At the same time, the physical property change of the fabric with respect to the change of the relative amount of the Co-PET in the microfiber was also examined to provide a directly applicable data set to the industry. The sample fabric used was warp 75/36(DTY) and weft 0.05d(PET/Co-PET, Sea Island Type Microfiber) twill fabric of 36 separated yarns+40/24(high shrinking yarn) with 130/48 ITY. The data set was made at various NaOH concentrations and steam temperatures with time as a main variable. The physical properties examined were the tensile properties. The results obtained were the tensile properties. The results obtained were 1. For a proper extraction of Co-PET (13.5%)from the microfiber with wet curing, it takes more than 5 min. in 8 and 12% of NaOH solutions but it takes only 3 min. in 18% of NaOH solution at 120℃. 2. For a proper extraction of Co-PET (13.5%) from the microfiber with wet curing, it takes 3∼5 min. in 12 and 14% of NaOH solution and it takes less than 3 min. in 18% of NaOH solution at 130℃. 3. The increasing ratio of WT increased with increasing NaOH concentrations and the equilibrium point reached was 3 min. at 120℃. 4. The WT increasing ratio was greater in 14 and 18% NaOH solutions than in 8 and 12% of NaOH solutions at 130℃. 5. The RT ratio changes at 120℃ in 8 and 12% of NaOH solutions were indifferent from that at 130℃ in 12% of NaOH solution. However, the RT was apparently decreased with increasing NaOH concentration.

Study on the measurement of Kimchi maturity by weight measuring method (중량법에 의한 김치 숙성도 판정에 관한 연구)

  • Park, Woo-Po;Lee, Sang-Jun;Kim, Ze-Uook
    • Applied Biological Chemistry
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    • v.33 no.3
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    • pp.257-260
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    • 1990
  • The weight increasing rate of soda lime, absorbing carbon $dioxide(CO_2)$ generated during fermentation at $25^{\circ}C$, was measured In investigate the maturity of Kimchi at every 6 hours. The increasing rate was maximum at 36hours It was compatible with pH, titrable acidity and sensory evaluation test in optimum curing time. So, this method is thought as useful one for the measurement of the maturity of Kimchi.

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Strength Characteristics of Soil-Cement Constructed in Seoul Urban Area (서울 도심지 내 지반에 시공한 소일-시멘트의 강도 특성)

  • Choo, Jin-Hyun;Kim, Young-Seok;Kim, Hak-Seung;Cho, Yong-Sang
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.03a
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    • pp.1206-1211
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    • 2010
  • Soil-cement, a hardened mixture of Portland cement, soil, and water that contain sufficient durability, has been widely utilised in Seoul urban construction sites to retain lateral earth pressures or reinforce grounds. However, little information has been reported about the strength characteristics of soil-cement constructed in Seoul urban area. In this study, we performed a number of unconfined test to the soil-cements mixed from soils sampled in 3 sites in Seoul urban area. Results indicate that unconfined strengths and optimum cement amounts of soil-cements are highly dependent on the proportion of coarse-grain particles of mixed soils. Furthermore, changes of unconfined strengths with curing time are diverse with respect to mixing conditions.

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