• Title/Summary/Keyword: Hydration rate

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A Study on Construction Methods of Roller Compacted Concrete Pavement for Bike Roads (자전거도로용 롤러 전압 콘크리트 포장의 시공 방안 연구)

  • Lee, Chang-Ho;Kim, Young-Kyu;Kang, Jae-Gyu;Park, Cheol-Woo;Lee, Seung-Woo
    • International Journal of Highway Engineering
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    • v.13 no.2
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    • pp.103-114
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    • 2011
  • Usage of bicycle has been supported the universal reduction of energy consumption and $CO_2$. For the same purpose, new constructions for long length bike roads are planned in Korea. Recently, laboratory tests of physical properties and resistance against environmental loading about optimum mix design of roller compacted concrete, that have advantages of high structural performance by cement hydration and aggregate interlocking, simple construction procedure and low construction cost, are performed for the effective construction of new bike roads. However, properties of roller compacted concrete had different results between laboratory and field tests since it had different compaction method. Also, construction method of roller compacted concrete are not defined for the application of bike roads since it had different demand performance such as thin pavement thickness, low strength and etc with road pavements. Thus, in this experimental research was launched to evaluate the core properties, visual inspection, compaction ratio, water content, thickness reduction rate of roller compaction, skid resistance and roughness by experimental construction about variable mix proportion and compaction method based on laboratory test results. And construction method of roller compacted concrete pavement were suggested for the application of bike roads.

Improved Storage Stability of Brown Rice by Coating with Rice Bran Protein (쌀겨 단백질 코팅에 의한 현미의 저장성 향상)

  • Kim, Kyung-Mi;Jang, In-Suk;Ha, Sang-Do;Bae, Dong-Ho
    • Korean Journal of Food Science and Technology
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    • v.36 no.3
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    • pp.490-500
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    • 2004
  • Brown rice grains were coated by spraying aqueous protein solution extracted from rice bran using 10% ethanol, and dried at room temperature. Coating procedure was repeated 1-5 times to determine effect of repeated coating, Quality changes in coated brown rice grains were observed during 8 weeks storage. Most coated rice grains gave lower peroxide and acid values, which indicate antioxidative effects of coating. Lipase and lipoxygenase activities generally decreased in grains coated more than three times. Microscopic images of whole kernel and longitudinal section revealed cracking on all brown rice grains including control, and hydration rate constants were not significantly different among treated grains. Compared to non-coated brown rice grains, those coated more than three times, after 8 week storage, showed better quality retention observed in (meaning not clear) higher water-binding capacity, lower gel consistency decrease, less browning, and better textural properties in cooked rice, resulting in better sensory quality.

Measuring external Radiation dose Ratio by Traits of Patients during Positron Emission Tomography(PET) (양전자단층촬영(PET)시 환자의 특성에 따른 외부 방사선량률 측정)

  • Cho, Yong-Gwi;Kim, Sung-Chul;Ahn, Sung-Min
    • The Journal of the Korea Contents Association
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    • v.13 no.12
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    • pp.860-868
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    • 2013
  • The purpose of this study is to ensure safety by measuring External radiation dose ratio (ERDR) by traits of patients in many ways after administering radiopharmaceutical($^{18}F$-FDG) for PET Torso scan, and to decrease ERDR of those to RI technologist, caretakers, and those who frequently exposed to radiation by arousing attention to radiation dose. Radiopharmaceutical was administered to 80 patients who conducted PET Torso from January to June, 2013. Radiation dose emitted from the patients was measured according to body shape(BMI), water hydration, height, amount of radiation administration. From the moment immediately after the radiopharmaceutical was administered, ERDR was measured by personal traits of patients. The radiation dose increased in proportion to the administered amount of the radiopharmaceutical, and there was no significant difference depending on the body shape of the patients. When water was supplied and the height was normal, the radiation dose was lower compared with the cases where water was not supplied and height was not normal. There is a need for making efforts to minimize the working time through sufficient education and mock training before those who RI technologist with sources of radiation for complying the radiation safety management rule. And they should minimize the ERDR by wearing a protective gear.

Proliposomal Clenbuterol Patch for Transdermal Delivery (프로리포솜을 이용한 클렌부테롤의 경피흡수 제제화)

  • Lee, Young-Joo;Chung, Suk-Jae;Lee, Min-Hwa;Shim, Chang-Koo
    • Journal of Pharmaceutical Investigation
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    • v.27 no.4
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    • pp.303-311
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    • 1997
  • Proliposomal patch of clenbuterol, ${\beta}_2-agonist$ bronchodilator, was prepared and its feasibility as a novel transdermal drug delivery system was examined. Proliposomal granules containing clenbuterol was prepared by a standard method using sorbitol and lecithin with (Rx 2) or without cholesterol (Rx 1). The porous structure of sorbitol in the proliposomes was maintained allowing tree flowability of the granules. Following contact with water, the granules were converted probably to liposomes almost completely within several minutes. It indicates that proliposomes may be hydrated, when they are applied on the skin under occlusive condition in vivo, by the sweat to form liposomes. Clenbuterol release from Rx 1 and Rx 2 proliposomes to pH 7.4 isotonic phospate buffer (PBS) across cellulose membrane (mol. wt. cut-off of 12000-14000) was retarded significantly compared with that from the mixture of clenbuterol powder and blank proliposomes. Interestingly, proliposomes prepared with lecithin and cholesterol (i.e., Rx 2 proliposomes) showed much more retarded release of clenbuterol than proliposomes prepared only with lecithin (i.e.. Rx 1 proliposomes), indicating that clenbuterol release from proliposomes can be controlled by the addition of cholesterol to the proliposomes. Proliposomal patches were prepared using PVC film as an occlusive backing sheet, two sides adhesive tape (urethane, 1.45 mm thickness) as a reservoir for proliposome granules and Millipore MF-membrane (0.45 mm pore size) as a drug release-controlling membrane. Rx 1 or Rx 2 proliposomes containing 4.6 mg of clenbuterol were loaded into the reservoir of the patch. Clenbuterol release from the patches to pH 7.4 PBS was determined using USP paddle (50 rpm)-over-disc release method. Clenbuterol release from the proliposomal patches was much more retarded even than from a matrix type clenbuterol patch (Boehringer Ingelheim ltd). Being consistent with clenbuterol release from the proliposomal granules, the release from the patches was highly dependent on the presence of cholesterol in the proliposomes : Patches containing Rx 2 proliposomes showed several fold slower drug release than patches containing Rx 1 proliposomes. When the patch containing Rx 1 proliposomes was applied on to the back of a hair-removed rat, clenbuterol concentration in the rat blood was maintained during 6-72 hrs. Transdermal absorption of clenbuterol from the patch was accelerated when the patch was prehydrated with 50 ml of pH 7.4 PBS before topical application. Above results indicate that sustained transdermal delivery of clenbuterol is feasible using proliposomal patches if the cholesterol content and pore size of the release rate-controlling membrane of patches, for example, are appropriately controlled.

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Physical and Chemical Properties of Cement Mortar with Gamma-C2S

  • Lee, Sung-Hyun;Kim, Kyungnam;Mabudo, Mabudo;Song, Myong-Shin
    • Journal of the Korean Ceramic Society
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    • v.53 no.2
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    • pp.194-199
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    • 2016
  • Presently, for the cement industry, studies that seek to reduce $CO_2$, because of the development of the plastic industry and demand for reduction of energy use, have been actively conducted among them, studies attempting to use Gamma-$C_2S({\gamma}-C_2S)$ to fix $CO_2$ have been actively conducted. The ${\gamma}-C_2S$ compound has an important function in reacting to $CO_2$ and stiffening through carbonatization in the air. The ${\gamma}-C_2S$ compound, reacting to $CO_2$ in the air, generates $CaCO_2$ within the pore structure of cement materials and densifies the pore structure this leads to an improvement of the durability and to the characteristic of resistance against neutralization. Therefore, in this experiment, in order to synthesize ${\gamma}-C_2S$, limestone sludge and waste foundry sands are used these materials are plasticized for 30 or 60 minutes at $1450^{\circ}C$, and are prevented from being cooled in the temperature range of $30{\sim}1000^{\circ}C$ when they are about to be cooled. XRD analysis and XRF analysis are used to determine the effects of this process on ${\gamma}-C_2S$ synthesization, the temperature at which a thing is plasticized, and the conditions for cooling that obtain in the plasticized clinker also, in order to confirm the $CO_2$ capture function, analysis of the major hydration products is conducted through an analysis of carbonatization depth and compressive strength, and through MIP analysis and XRD Rietveld analysis. As a result of these analyses, it is found that when ${\gamma}-C_2S$ was synthesized, the clinker that was plasticized at $1450^{\circ}C$ for one hour demonstrated the highest yield rate the sample with which the ${\gamma}-C_2S$ was mixed generated $CaCO_3$ when it reacted with $CO_2$ therefore, carbonatization depth and porosity were reduced, and the compressive strength was increased.

Phase II Study of Paclitaxel and Cisplatin as Second-line Chemotherapy in Advanced Non-small Cell Lung Cancer (진행성 비소세포폐암에 대한 2차 화학요법으로 paclitaxel과 cisplatin의 제 2상 임상연구)

  • Seo, Yeoung-Tae;Kim, Bong-Seog;Go, Ji-Young;Choi, Dong-Suk;Choi, Seong-Ho;Kim, Hye-Jin;Ahn, Young-Mi;Roh, Yong-Ho;Lee, Kyung-Hee
    • Journal of Yeungnam Medical Science
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    • v.21 no.2
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    • pp.198-206
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    • 2004
  • Background: To evaluate the efficacy and safety of paclitaxel and cisplatin against advanced non-small cell lung cancer (NSCLC) as a second-line chemotherapy. Subjects and Methods: Twenty-five patients were enrolled. The patients received 200 $mg/m^2$ paclitaxel as a 3-hour intravenous infusion and 60 $mg/m^2$ cisplatin as 2D-minute intravenous infusion with vigorous hydration on day 1 every 28 days. The response was assessed every 2 cycles. Results: All 25 patients were assessed for their response and toxicity. Partial responses were observed in 5 patients. The overall response rate was 20%(95% confidence interval, 4%-36%) and the median response duration was 4.5(range, 2-11) months. The median time to progression was 3.3(range, 0-14) months. The median overall survival of all patients was 7.4(range, 1.3-39) months. The hematologic toxicities were minor and easily controlled. Conclusion: The combination chemotherapy of paclitaxel and cisplatin as a second-line treatment has a moderate efficacy with an acceptable toxicity in patients with advanced NSCLC.

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Fire resistance assessment of precast fireproof duct slab (프리캐스트 방식 내화풍도슬래브의 화재저항성 평가)

  • Choi, Soon-Wook;Kang, Tae-Ho;Lee, Chulho;Kim, Se Kwon;Kim, Tae Kyun;Chang, Soo-Ho
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.22 no.6
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    • pp.669-680
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    • 2020
  • In Korea, fireproof performance is evaluated through a series of fire-resistance tests for important structures, and the performance standard follows the guidelines suggested by ITA. The fireproof duct slab manufactured by combining the slab and the fireproof material with a precast method is effective in that it can eliminate the construction time of the fireproof material. In this study, a series of fire resistance tests was performed on the fire test specimens under the RWS fire scenario in order to secure the fire resistance performance of the precast fireproof duct slab. As a result of the test, it was found that the fireproof performance was secured when the thickness of the fireproof material was 30 mm or more. In both fireproof materials and concrete, the rate of temperature change initially increased, then decreased, and then increased again, and the temperature at the inflection point was measured as 110℃ for all fireproof materials and concrete. It is judged that this occurs when the C-S-H (CaO-SiO2-H2O) generated by the hydration reaction in both the fireproof material and concrete is dehydrated.

Engineering Properties of PHC Pile Considering Replacement Ratio of Ground Granulated Blast-Furnace Slag and Curing Conditions (고로슬래그 미분말의 치환율 및 양생조건을 고려한 PHC파일의 공학적 특성)

  • Shin, Kyoung-Su;Lim, Byung-Hoon
    • Journal of the Korea Institute of Building Construction
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    • v.18 no.5
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    • pp.439-446
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    • 2018
  • The PHC pile has been increasingly used due to its implementation of the top-base method, which is advantageous in high penetration rate and bearing capacity reinforcement. Typically, when a PHC pile is manufactured, high-strength mixed materials are mainly used to enhance the compressive strength. However, recent studies have been conducted to utilize ground granulated blast-furnace slag (GGBS) in terms of economic efficiency. For this reason, this study manufactured PHC pile considering the replacement ratio and curing conditions of GGBS instead of high-strength mixed materials, and further investigated the engineering properties of the PHC pile. According to the experimental results, the compressive strength of GGBS-replaced PHC pile increased by steam curing, and particularly, PHC pile with 20% replacement of GGBS under $80^{\circ}C$ steam curing condition showed a compressive strength of approximately 84MPa. Furthermore, the experimental results confirmed that more hydration products were generated under the $80^{\circ}C$ steam curing condition than that under the $20^{\circ}C$ steam curing condition, which would affect the higher density of the PHC pile as well as the increase in the compressive strength.

An Experimental Study on Rapid Repairing Mortar for Road with Steel Slag (철강 슬래그를 사용한 도로용 긴급보수 모르타르에 관한 실험적 연구)

  • Jung, Ui-In;Kim, Bong-Joo;im, Jin-Man;Kwak, Eun-Gu
    • Journal of the Korea Institute of Building Construction
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    • v.18 no.5
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    • pp.419-427
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    • 2018
  • The purpose of this study is to recycle steel slag generated from the iron producing process and to use steel slag as a construction material which is currently landfilled Steel slag is subjected to aging treatment due to the problem of expansion and collapse when it reacts with water. The Slag Atomizing Technology (SAT) method developed to solve these problems of expanding collapse of steel slag. In this study, experimental study on the emergency repair mortar using the reducing slag, electric arc furnace slag and silicon manganese slag manufactured by the SAT method is Reduced slag was shown an accelerated hydration when it was replaced with rapidly-setting cement, and the rate of substitution was equivalent to 15%. It is shown that the electric furnace oxide slag is equivalent to 100% of the natural aggregate, and it can be replaced by 15-30% when the silicon manganic slag is substituted for the electric furnace oxide slag. With the above formulation, it was possible to design the rapidly repair mortar for road use. These recycling slags can contribute on achieving sustainability of construction industry by reducing the use of cement and natural aggregates and by reducing the generation of carbon dioxide and recycling waste slag.

Cooking Conditions and Textural Changes of Cooked Rice Added with Black Rice (흑미 혼용밥의 취반조건과 텍스쳐의 변화)

  • Kim, Du-Woon;Eun, Jong-Bang;Rhee, Chong-Ouk
    • Korean Journal of Food Science and Technology
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    • v.30 no.3
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    • pp.562-568
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    • 1998
  • Rice (Dongjin-byeo) added with black rices (Chindo and Suwon-415) was cooked and the changes of texture and color of this cooked rice were investigated by texture analyser and color & color difference meter. The hydration time to come to the equilibrium condition was at least 11 hr in black rices. The optimum ratio of water to cooked rice added with black rice was 1.6 (ratio of water to rice) and the hardness of cooked rice added with 5% Chindo black rice was $5.66\;kg_f$. Regardless of ratio of water to rice, Hunter a value increased as the ratio of black rice addition to rice increased, while L value decreased. The color elution rate of Suwon 415 was 4 times greater than that of Chindo black rice. The pH of the steep water of Suwon 415 at $20^{\circ}C$ during 120 min decreased from pH 6.40 to pH 6.16 as the steeping time increased. The optimum heating time by microwave oven of cooked rice added with black rice was between $90{\sim}120\;sec$ to recover the original texture after cold storage treatment of 7 days.

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