• Title/Summary/Keyword: Hydration characteristics

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Quality Characteristics of Yukwa (Popped Rice Snack) made by Different Varieties of Rice (쌀 품종별 유과제조 특성)

  • Shin, Dong-Hwa;Kim, Myung-Kon;Chung, Tae-Kyu;Lee, Hyun-Yu
    • Korean Journal of Food Science and Technology
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    • v.21 no.6
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    • pp.820-825
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    • 1989
  • Yukwa (one of most popular Korean traditional popped rice snacks) was made by four different varieties of rice, Shinsun (Japonica) and Hangang $(Japonica{\times}Indica)$ which are waxy rice and Dongjin (Japonica) and Samgang $(Japonica{\times}Indica)$ which are non waxy rice, for their quality by total expansion volume, hardness and brittleness. It was notified that hydration rate of waxy and non waxy rice for preparation of Yukwa were different by 30% and 42% in moisture content respectively soaked at $12^{\circ}C$ for 12 hours and the gelatinization temperature of their starch was $64.5-67.5^{\circ}C$ with no big difference by varieties. The quality of Yukwa was deeply related with amylose contents ranging from 18.5% of non waxy rice to 2-3% of waxy rice. Superior quality (p<0.05) was got from waxy rice. Lactic acid bacterial fermentation didn't improve the quality, and soybean and rice bran oil can be used for popping in even value.

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Experimental Study on Lateral Pressure Characteristics of a Formwork for High-Flowable and High-Strength Concrete (고유동 고강도 콘크리트용 거푸집의 측압 특성에 관한 실험적 연구)

  • Ko, Young-Kon;Kim, Cheol-Hwan;Hwang, Jae-Woong;Yi, Seong-Tae
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.19 no.3
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    • pp.130-138
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    • 2015
  • In this study, to examine the application of cast-in-place of high-flowable and high-strength concrete, an experimental study on the lateral pressure of a formwork was preformed. The experiment specimens, which have different casting height and casting speed were prepared. The lateral pressure and the change of temperature from test specimens were obtained. The maximum lateral pressure was shown to lateral pressure of fresh concrete. Immediately after placing, the lateral pressure starts to decrease and, after 12 hours, it showed a stabilization. The decreased tend of the lateral pressure was similar with normal-strength concrete, which appears stabilization after 3~4 hours from casting completion. The more casting speed is fast, the more maximum lateral pressure is high, but pressure reduction with the lapse of time was nearly similar. In addition, it was found that there was no direct relation between the hydration heat and the lateral pressure reduction.

Influence of Micro-Structural Characteristics of Concrete on Electrical Resistivity (콘크리트의 미세구조 특성이 전기저항에 미치는 영향)

  • Yoon, In-Seok
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.17 no.6
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    • pp.122-129
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    • 2013
  • Since electrical resistivity of concrete can be measured in a more rapid and simple way than chloride diffusivity, it should be primarily regular quality control of the electrical resistivity of concrete which provides the basis for indirect of quality control of chloride diffusivity during concrete construction. If this is realized, the electrical resistivity of concrete can be a crucial parameter to establish maintenance strategy for marine concrete structures. The purpose of this study is to develop, design and test a surface electrical resistivity measurement protocol. Microstructural affecting factors such as capillary water, porosity, tourtousity, and so on, on the electrical resistivity of concrete were examined taking into account for mixing proportion properties, and hydration stage. This study can provide a non-destructive approach for durability design of marine concrete. From the relationship between electrical resistivity and chloride diffusivity, it is expected that the result is subsequently used as a calibration curve for an indirect control of the chloride diffusivity based on regular measurements of the electrical resistivity during concrete construction.

Feasibility Study on the Use of CFBC Ash as Non-sintered Binder (순환유동층 보일러애시를 활용한 비소성 결합재로써의 활용 가능성 검토)

  • Kang, Yong Hak;Lim, Gwi Hwan;Kim, Sang Jun;Choi, Young Cheol
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.22 no.5
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    • pp.119-126
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    • 2018
  • Recently, the production of circulating fluidized bed combustion ash has been increased in thermal power plants. The addition of limestone for the desulfurizing effect of circulating fluidized bed boiler ash increases the content of CaO and $SO_3$ contained in ash, which is higher than the free fly ash in general fly ash. Unlike conventional fly ash, the circulating fluidized bed combustion ash has a high reactivity when it comes into contact with water due to its hydraulic properties and high free-CaO content. The aim of this study is to investigate the possibility of non-sintered binder by using self-cementing properties of circulating fluidized bed combustion ash. The mechanical and hydration characteristics were investigated according to the content of CFBC ash. In addition, the effects of gymsum type and content on the compressive strength and micro-structure of non-sintered binder pastes.

A Study on the Heat Storage System for Chemical Heat Pump Using Inorganic Hydrates (II) -Numerical Analysis of Heat Transfer in CaO Hydration Packed Bed- (화학열펌프에 있어서의 무기수화물계 축열시스템에 관한 연구(II) -CaO 수화반응층의 전열해석-)

  • Park, Young-Hae;Chung, Soo-Yull;Kim, Jong-Shik
    • Applied Chemistry for Engineering
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    • v.7 no.3
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    • pp.518-529
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    • 1996
  • To develope chemical heat pump using available energy sources such as solar heat and many kinds of waste thermal energy we have studied the enhancement effect of inserted fins in cylindical packed bed reactor. Two dimensionnal(radial and circumferential) partial differential eqaetions, concerning heat and masstransfer in CaO packed bad, are solved numerically to describe the characteristics of the reaction of fins inserted reactor and heat transfer. The results obtained by numerical analysis about two dimensional profiles of temperature and conversion in the reactant in the packed bed and exothermic heat amount released from the reactor are follows; -. The insertion of fins in reactor can redue the reaction completion time by half. -. The rate of thermochemical reaction depends of the temperature and concentration and it is also governed by the boundary conditions and heat transfer rate in the particle packed bed.

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Effects of CNT Additions on Mechanical Properties and Microstructures of Cement (CNT 첨가량에 따른 시멘트의 역학성능 및 미세구조의 영향)

  • Oh, Sungwoo;Oh, Kyeong-seok;Jung, Sang-hwa;Chung, Wonseok;Yoo, Sung-won
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.21 no.6
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    • pp.162-168
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    • 2017
  • Carbon nanotube(CNT) is one of the promising construction materials to produce concrete with high strength and durability by adding in the concrete mixtures from various researches. Also, its superior heat conductivity can be one of the options to develop self-heating concrete. In this research, the fundamental study was conducted to investigate mechanical properties and microstructures of cement pastes and mortars by strength tests and porosity measurement with several CNT additions, which were 0 wt%, 0.115 wt%, 0.23 wt% and 0.46 wt% of CNT-cement ratio. Compressive and flexural strength test were conducted at 3, 7 and 28 days, and pore characteristics were investigated by mercury intrusion porosimetry. SEM-EDS and Thermogravimetric analysis(TGA) were conducted to prove the hydration product types and CNT dispersion in the cement matrix. As a result, even though high amount of CNT additions were caused worse performance, mixtures with 0.115 wt% of CNTs developed the similar performance with plain mixture.

Aggravating and Mitigating Patient Factors Affecting Mild to Moderate Atopic Dermatitis (중등도 이하 아토피 피부염에 영향을 미치는 환자 요인)

  • Kang, Dong-Won;Kim, Yoon-Bum
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.33 no.4
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    • pp.1-15
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    • 2020
  • Objectives : To investigate aggravating and mitigating factors of atopic dermatitis and to utilize the outcome in treatment planning. Methods : The research has a cross-sectional study design. Patients' SCORing Atopic Dermatitis (SCORAD) Index, demographic, physical characteristics, social history, serologic index and skin related instrumental measurements were analyzed with correlation and regression analysis method. Results : 48 patients in total were enrolled in the study. Skin Surface Hydration (SSH) and sex were found to be statistically significant aggravating and mitigating factors. As SSH increased, Total SCORAD (tSCORAD) and Objective SCORAD (oSCORAD) increased as well. As SSH decreased, tSCORAD and oSCORAD decreased as well. Female patient had a higher probability of suffering from severer subjective symptoms than that of male. Age, body mass index (BMI), alcohol consumption and smoking, transepidermal water loss (TEWL), IgE, IL-4, IL-5, IL-6, IFN-γ were found not to be statistically significant. There was no correlation between Subjective SCORAD (sSCORAD) and oSCORAD neither with Eczema Area and Severity Index (EASI). Conclusions : Increasing cutaneous moisture should be included in the treatment plan of atopic dermatitis. More emphasis should be put on alleviating subjective discomforts of female patients than that of male. Establishing separate strategies of managing objective eczema status and subjective discomforts respectively should be considered.

Percutaneous Absorption Characteristics of Antidepressant Paroxetine (항우울제인 Paroxetine의 피부 투과 특성 연구)

  • Jung, Duck-Chae;Hwang, Sung-Kwy;Oh, Se-Young
    • Journal of the Korean Applied Science and Technology
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    • v.28 no.2
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    • pp.170-177
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    • 2011
  • Transdermal drug delivery(TDS) offers many important advantages. For instance, it is easy and painless, it protects the active compound from gastric enzymes, and it avoids the hepatic first-pass effect. Also, it is simple to terminate the therapy if any adverse or undesired effect occurs. But skin is a natural barrier, and only a few drugs can penetrate the skin easily and in sufficient quantities to be effective. Therefore, in recent years, numerous studies have been conducted in the area of penetration enhancement. The most commonly used transdermal system is the skin patch using various types of technologies. Compared with other method of dosage, it is possible to use for a long term. It is also possible to stop the drug dosage are stopped if the drug dosage lead to side effect. Polysaccharide, such as xanthan gum and algin were selected as base materials of TDS. Also, these polymers were characterized in terms of enhancers and drug contents. Among these polysaccharide, the permeation rate of Paroxetine such as lipophilic drug was the fastest in xanthan gum matrix in vitro. We used glycerin, PEG400 and PEG800 as enhancers. Since dermis has more water content(hydration) than the stratum corneum, skin permeation rate at steady state was highly influenced when PEG400 was more effective for lipophilic drug. Proper selection of the polymeric materials which resemble and enhance properties of the delivering drug was found to be important in controlling the skin permeation rate.

Percutaneous absorption Characteristics of Anti hyperlipidemia Gel Ointment using Fibric acid (Fibric acid를 이용한 항고지혈증 겔 연고의 경피 흡수 특성)

  • Jung, Duck-Chae;Hwang, Sung-Kwy;Oh, Se-Young
    • Journal of the Korean Applied Science and Technology
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    • v.27 no.4
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    • pp.407-414
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    • 2010
  • New biological treatments were being developed at a record place, but their potential could be compromised by a significant obstacle: the delivery of these drugs into a body. Pharmaceutical delivery is now nearly as important as product. New systems are being developed, and Drug Delivery Markets Series cover these new systems. Transdermal Delivery System(TDS) is often used as a method of drug dosage into the epidermic skin. An approach used to delivery drugs through the skin for therapeutic use as an alternative to oral, intravascular, subcutaneous and transmucosal routes. Various transdermal drug delivery technologies are described including the use of suitable formulations, carriers and penetration enhancers. The most commonly used transdermal system is the skin patch using various types of technologies. Compared with other methods of dosage, it is possible to use for a long term. It is also possible to stop the drug dosage are stopped if the drug dosage lead to side effect. Polysaccharides, such as karaya gum and glucomannan, were selected as base materials of TDS. Also, these polymers were characterized in terms of enhancers, drug contents. Among these polysaccharide, the permeation rate of karaya gum matrix was fastest in fibric acid(ciprofibrate) such as lipophilic drug in vitro. We used glycerin, PEG400 and PEG800 as enhancers. Since dermis has more water content(hydration) than the stratum corneum, skin permeation rate at steady state was highly influenced when PEG400 was more effective for lipophilic drug. Proper selection of the polymeric materials which resemble and enhance properties of the delivering drug was found to be important in controlling the skin permeation rate. Especially, this result suggests a possible use of polysaccharide gel ointment matrix as a transdermal delivery system of anti-hyperlipoproteinemic agent.

The Bond Characteristics of Ultra Rapid Hardening Mortar for Repair using Magnesia-Phosphate Cement (마그네시아 인산염 시멘트를 이용한 초속경 보수 모르타르의 접착특성)

  • Lee, Sun-Ho;Kwon, Hee-Sung;Paik, Min-Su;Ahn, Moo-Young;Lee, Young-Do;Jung, Sang-Jin
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.04a
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    • pp.609-612
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    • 2008
  • Ultra Super Early Strength Cement is a material that satisfies these requirements. early hydration heat however, is significant over regular concrete, thus discretion is advised for thermal cracks in accordance with heat generation when constructing a large-scale structures. In addition, the negative point that it is difficult to achieve required strength in a short period of time following rubbing process while retaining workability, the cement is being used conditionally for engineering material and Ultra Super Early Strength Cement for maintenance material for construction doesn't exist. Magnesia Phosphate Cement, which is currently under studies in overseas uses no extra admixture and has strong points of Ultra Super Early Strength as well as favorable construction-ability and adhesive stability to the prototype concrete. These factors stem recognition that it could be used as maintenance material for construction of diverse applicability. In order to provide necessary data to increase practicality of the magnesia phosphate cement for Ultra Super Early Strength Mortar, the study carried out simulate experiment on member of framework to review field applicability.

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