• Title/Summary/Keyword: 경화촉진제

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Effects of K-Sorbate, Salt-Fermented Fish and $CaCl_2$ Addition on the Texture Changes of Chinese Cabbage During Kimchi Fermentation (보존료, 젓갈, $CaCl_2$ 첨가가 김치발효중 배추잎의 조직감변화에 미치는 영향)

  • Hwang, In-Ju;Yoon, Eu-Jeong;Hwang, Seong-Yun;Lee, Cherl-Ho
    • Journal of the Korean Society of Food Culture
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    • v.3 no.3
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    • pp.309-317
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    • 1988
  • The effects of $CaCl_2$, K-sorbate, and fermented fish sauces and blanching on the texture of Chinese cabbage of Kimchi were evaluated. The addition of salt-fermented shrimp or salt-fermented anchovy accelerated the pH reduction, acidity increase and reducing sugar consumption, but K-sorbate, Ca-chloride and blanching suppressed the ripening process of Kimchi. The latter retarded the softening rate of Chinese cabbage during Kimchi fermentation, as demonstrated by the cutting force, compression force, recovered height and work ratio. The sensory evaluation confirmed the results of instrumental texture measurments. The instrumental measurements, i.e. pH, acidity cutting thickness, cutting force and compression test parameters, showed acidity acidity was calculated as % lactic acid attributes, i.e. the preferences for taste, appearance and texture, and the level of crispiness, hardness, chewiness and fibrousness. The pH of Kimchi was appeared to be an important quality parameter, whiih had significant correlations with the taste, appearance, chewiness, hardness, fibrousness and crispiness.

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Synthesis and characterization of PPG-based urethane-modified epoxy resin for enhancing impact resistance of epoxy composite resin (에폭시 복합수지의 내충격성을 향상을 위한 PPG 기반 우레탄 변성 에폭시 합성 및 특성 분석)

  • Hwang, Chiwon;Jeon, Jaehee;Ahn, Dowon;Yu, Youngchang;Lee, Wonjoo
    • Journal of Adhesion and Interface
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    • v.23 no.2
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    • pp.44-52
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    • 2022
  • Epoxy resin has the disadvantage of being easily destroyed by instantaneous impact due to its high crosslinking density despite its high glass transition temperature (Tg) and excellent properties. To compensate for this, in this study, polyol was synthesized by ring opening polymerization of propylene glycol (PPG) diamine, Jeffamine D 2000 and propylene carbonate, and urethane modified epoxy was synthesized using this. The properties of the synthesized urethane modified epoxy were confirmed by FT-IR, H-NMR. To confirm the degree of improvement in impact resistance as an adhesive, a urethane modified epoxy adhesive was prepared by mixing a digylcidyl ether bisphenol A (DGEBA) with curing agent and curing accelerator. Properties test of urethane modified epoxy were shear strength, tensile strength and impact strength. As a result, excellent results were obtained in all test when the ratio of DGEBA : urethane modified epoxy was 8:2.

Evaluating Early Age Shrinkage Behavior of Ultra High Performance Cementitious Composites (UHPCC) with CSA Expansive Admixture and Shrinkage Reducing Agent (CSA계 팽창재 및 수축 저감제의 혼입에 따른 UHPCC의 초기 수축 거동 평가)

  • Yoo, Doo-Yeol;Park, Jung-Jun;Kim, Sung-Wook;Yoon, Young-Soo
    • Journal of the Korea Concrete Institute
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    • v.23 no.4
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    • pp.441-448
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    • 2011
  • In this study, experimental tests of chemical and autogenous shrinkage were performed to evaluate the early age shrinkage behaviors of ultra high performance cementitious composites (UHPCC) with various replacement ratios of silica fume (SF), shrinkage reducing agent (SRA), expansive admixture (EA), and superplasticizer (SP). Starting time of self-desiccation, was analyzed by comparing the setting times and the deviated point of chemical and autogenous shrinkage strains. The test results indicated that both SF and SRA augment the early age chemical shrinkage, whereas SP delays the hydration reaction between cement particles and water, and reduces chemical shrinkage. About 49% of autogenous shrinkage was depleted by synergetic effect of SRA and EA. The hardening of UHPCC was catalyzed by containing EA. Self-desiccation of UHPCC occurred prior to the initial setting due to the high volume fraction of fibers and low water-binder ratio (W/B).

Development of Fluorite-free Desulfurizing Agent for Molten Iron using Al-dross and Ladle Slag (알루미늄 드로스와 래들 슬래그를 활용한 무형석 용선 탈황제 개발)

  • Lee, Chang-Hyun;Koo, Yeon-Soo;Lee, Man-Seung
    • Resources Recycling
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    • v.27 no.5
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    • pp.49-53
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    • 2018
  • In developing an optimum steelmaking process, the purity of the product, environmental impact, capability and cost of the process should be considered. Desulfurization of molten iron is conducted during preliminary treatment stage before converter operation. Although fluorite is added as a desulfurizing agent in CaO and $CaCO_3$ based agents, the concentration of fluorine in slag is strictly regulated. In order to develop desulfurizing agent without fluorine, CaO was mixed with Al dross and ladle slag containing alumina. The characteristics and desulfurizing capacity of the CaO based desulfurizing agent thus prepared were tested by varying temperature of Kanvara Reactor. Our results showed that the desulfurizing capacity of the samples prepared in this work was found to be similar to that of the traditional desulfurizing agents with fluorine.

A Study on the Effect of Calcium-Chloride Content on the Strength of Mortar (염화(鹽化)칼슘의 함량(含量)이 Mortar의 강도(强度)에 미치는 영향(影響)에 관(關)한 연구(硏究))

  • Sung, Chan-Yong;Kang, Sin-Up
    • Korean Journal of Agricultural Science
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    • v.6 no.2
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    • pp.185-191
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    • 1979
  • Compressive and tensile strengths of commonly being used mortar and mortar specially hardened by adding 1%, 2% and 3% of $CaCl_2$ were compared under the different mixing ratio of mortar and ages to investigate the effect of $CaCl_2$ which is being used as a promotor for coagulation and hardness, on the strength of mortar. The results obtained were as follows: 1. The compressive strength of mortar hardened by addition of $CaCl_2$ was higher than that of commonly being used mortar. The highest compressive strength of mortar was obtained when 2% of $CaCl_2$ were added. 2. The tensile strength of mortar, which was made by adding $CaCl_2$ and aged for seven days, was higher than that of commonly being used mortar. The highest tensile strength of mortar was obtained when 1% of $CaCl_2$ was added and aged for 28 days. And the tensile strength of mortar with 2% of $CaCl_2$ was lower than that of commonly being used mortar. 3. When the amount of $CaCl_2$ added was higher than 3%, the mortar was abruptly hardened and thereby occurred crack was considered lowering strength of mortar. 4. The rich mix was effective for the increasing the compressive and tensile strength before seven days of age and less effective after seven days of age. Therefore, the addition of one to two per cent of $CaCl_2$ would be effective for promoting initial strength of mortar during winter season.

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An Experimental Study on the Carbonation Depth of Cement Paste Using Carbonation Reaction Accelerator (탄산화 반응 촉진제를 이용한 시멘트 페이스트의 탄산화 깊이에 관한 실험적 연구)

  • Seok-Man Jeong;Wan-Hee Yang;Dong-Cheol Park
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.11 no.4
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    • pp.349-354
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    • 2023
  • This study wa s conducted a s pa rt of ma ximizing the use of ca rbon dioxide by a pplying CCU(Ca rbon Ca pture, Utiliza tion) a mong technologies for reducing CO2 in the cement industry. In a carbon dioxide curing environment, changes in carbonation depth and changes in basic physical properties by age due to the mixing of carbonation reaction accelerators were usually targeted at Portland cement paste. In addition, in order to check the fixed amount of CO2 in the concrete field, a thermal analysis method was applied to evaluate CaCO3 decarbonization at high temperatures. As a result of the evaluation, it was confirmed that the carbonation depth in the cured body significantly increased due to the incorporation of CRA in the carbonation depth diffusion performance. In addition, it was confirmed that the weight reduction rate increased by 23.8 % and 40.77 %, respectively, compared to Plain, in the order of curing conditions for constant temperature and humidity and curing conditions for carbonation chambers, so it was confirmed that the amount of excellent CaCO3 produced by the addition of CRA increased as the concentration of CO2 increased.

The Nutritional Aspect of Tofu (두부가 인체에 미치는 영양학적 고찰)

  • Jung, Moon-Kyung;Kim, Sung-Hwan
    • Journal of the Korea Convergence Society
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    • v.7 no.3
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    • pp.177-184
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    • 2016
  • The purpose of this study was to nutritional aspect of tofu. Tofu is a widely-enjoyed food made from soybeans, and it is a great example of how a simple food like soybeans can be woven into human food traditions in a way that is natural, inexpensive, and nourishing. One of the most important things to remember about tofu is its basic whole food nature. Tofu is produced with significantly less processing than most low-fat soymilks, it is a soy food that is much closer to a "whole foods" category than soy protein isolates and concentrates. From a health benefits standpoint, there are also benefits to tofu that has been fermented. Replacing meat and dairy with tofu and other soy products would also lower our total cholesterol intake by about 125 mg per day and our saturated fat by about 2.4 g per day. These nutritional changes, in turn, would lower our risk of several chronic diseases, including cardiovascular and cerebrovascular diseases.

Shear Behavior of $Carbon/BMI({\pm}45^{\circ})_{2s}$By Acoustic Emission (음향방출을 통한 $Carbon/BMI({\pm}45^{\circ})_{2s}$의 전단 거동)

  • Lee, Taek-Su;Lee, Jong-Mun;Lee, Jae-Rak
    • Korean Journal of Materials Research
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    • v.4 no.8
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    • pp.888-894
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    • 1994
  • In detail of fracture and mechanical properties to carbon/BMI$(\pm 45^\circ)_{2s}$ discusses by acoustic emission and tensile testing. The bismaleimide resin from Boots Technochemie Co. was toughened by TM 120 from same Co. The weight proportions of TM 120 were fixed as 0, 5, 10, 15, 20, 25phr. The 0.2phr of 1, 4-diazobicyclo-(2, 2, 2)-octane(DABC0) was used as the accelerator. The used carbon fiber was T300 from Toray Co. The optimum additional proportion of TM120 was proved as 20phr by mechanical testing and at the same time by the results of acoustic emission. toughening agent gives significant influences on the fracture phenomena and mechanical strength.

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An Investigation of How the Accelerator Effects the Setting Time and The Headness of Plaster Products (석고제품(石膏製品)에 촉진제(促進劑) 사용시(使用時) 경화시간(硬化時間) 및 경도(硬度)에 미치는 영향(影響)에 관(關)한 실험적(實驗的) 연구(硏究))

  • Hwang, Seung-Sig
    • Journal of Technologic Dentistry
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    • v.19 no.1
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    • pp.43-54
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    • 1997
  • This investigation is carried out of inqurie into the effects of the accelerator on the setting time and haedness when it is used with plaster products. Plaster($\beta$), dental hard stone($\alpha$), and limproved dental hard stone($M{\alpha}$) are selected as the objects of the investigation, since they are most common materials for dental plaster products. Setting time is gauged by means of Vicket Needle and Gilmore Needle, and hardness is gauged by means of Brinell and Vicket Hardness machines. Samples of each material are made in the standerd water powder ratio and with the accelerator repectively, Every material is tested five times each. The results of the tests are as fallow : 1) In each case the setting time is shortened when the accelerator is used. 2) Of the three materials the hardness of the plaster was lowest A($\beta$) < B($\alpha$) < C($M{\alpha}$)} 3) In each case the hardness of the samples made in the standard water powder ratio were higher than that of the sample made with the accelerator. A1 > A2 ; B1>B2 ; C1>C2 4) Final Conclusion : Higher quality cast is expected when it is made in the standard water powder ratio.

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Adhesion and Lifetime Extension Properties of Electrical Conductive Paint Stored under of Nitrogen Atmosphere (질소환경에서 보관된 전기전도성 페인트의 접착 및 수명연장 특성)

  • Shin, Pyeong-Su;Kim, Jong-Hyun;Baek, Yeong-Min;Park, Ha-Seung;Park, Joung-Man
    • Journal of Adhesion and Interface
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    • v.20 no.1
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    • pp.9-14
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    • 2019
  • The change of three different reagents for electrical conductive paint using aircraft coating with elapsing time of exposure to different condition was investigated. Three different reagents were poured into the vial bottles, stored in air condition and room temperature and observed with elapsing days. In addition, adhesion property of paint was tried using cross cut tape test after storage of $N_2$ atmosphere. The weight of each different reagent was measured along with elapsing time. To confirm the change of chemical component with exposure of air atmosphere, FT-IR was performed. The weight of part A and Part B decreased slightly whereas the weight of part C decreased rapidly and the precipitation was remained. The part B was cured after exposure of $N_2$ atmosphere and the 2250 cm-1 from FT-IR peak decreased slowly at the same time. It was considered that the water contained in air accelerated the reaction of -NCO functional groups and it caused the curing whereas $N_2$ atmosphere not contained water and it resulted in the retardancy of curing.