• Title/Summary/Keyword: heat cured

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The Effect of ZnO on the Hydration Reaction and Physical Properties of Cement (Cement의 수화반응 물리특성에 미치는 ZnO의 영향)

  • 김홍기;추용식;이경희;송명신
    • Journal of the Korean Ceramic Society
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    • v.34 no.4
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    • pp.399-405
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    • 1997
  • With the increase of ZnO content, heat of hydration decreased. For specimens containing ZnO more than 0.6 wt.%, the compressive stength of cement cured for 28 days could not be measured because setting was not occurred. With the increase of ZnO content, Blaine specific surface area of cement was decreased and the residue of 45 ${\mu}{\textrm}{m}$ and 90 ${\mu}{\textrm}{m}$ was increased when cement was ground. That is, grindability became worse as ZnO increased in clinker. The difference of color as a function of ZnO content could not be observed, but in the excess of amount of ZnO added, color became more white and reddish yellow.

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Durable Press Finish of Cotton via Dual Curing Using UV Light and Heat

  • Jang, Jinho;Yoon, Ki-Cheol;Ko, Sohk-Won
    • Fibers and Polymers
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    • v.2 no.4
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    • pp.184-189
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    • 2001
  • Continuous photografting/crosslinking of polyethyleneglycol dimethacrylate oligomers onto cotton using a water-soluble benzophenone photoinitiator was investigated. Photografting increased with increasing irradiation dose, oligomer concentration and photoinitiator concentration. Maximum grafting efficiency of DM 400 and 600 were 83% and 79%, respectively. the photografting increased the wrinkle resistance of cotton implying surface crosslinking of cotton. bothsurface crosslinking and bulk crosslinking of cotton were accomplished via dual curing of a mixed formulation containing both a thermally curable component (BTCCA/SHP) and a UV-curable component. The wrinkle resistance of the crosslinked cotton was found to be higher when cured by thermal curing due to the facile post-polymerization of the UV active component. The presence of crosslinks in the dually crosslinked cotton was verified with FT-IR and thermogravimetric analysis.

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Solar Energy Utilization in a Greenhouse Bulk Curing and Drying System. (II) (Greenhouse Bulk 건조기에 의한 태양열이용에 관한 연구 (제2보))

  • 이철환;변주섭
    • Journal of the Korean Society of Tobacco Science
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    • v.5 no.1
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    • pp.79-85
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    • 1983
  • The greenhouse bulk curing and drying system utilization of the direct solar energy was tested to evaluate that how much fuel could be saved for curing flue-cured tobacco at the Dae Gu Experiment Station (North latitude : $35^{\circ}$49'), in 1979-1982. The air temperature and total radiation were 19.0 to 38.5$^{\circ}C$ and 1311.0 to 1412.7 cal/$\textrm{cm}^2$/day during the 4 replicated curing test, respectively. The greenhouse bulk curing and drying system was able to cut fuel consumption by 32% compared with the conventional bulk curing barn. We could obtain almost same utilization efficiency of solar energy in 1982 compare with normal year, mainly increasing the heat receiving area.

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Study on the Seop-Gye's constitution theory for the connection with 'the differentiation of syndromes' and the general body form diagnosis (전신형태 진단과 변증시치의 연계를 위한 엽계의 형태체질론 연구)

  • Kim Gyeong Cheol;Lee Yono Tae;Shin Soon Shik
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.18 no.1
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    • pp.22-27
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    • 2004
  • Seop-Gye divided up the constitution's strength and weakness, and so he cured disease by the 'cold and heat'. 'deficiency and excessiveness' means on the basis of the YINㆍYANG of constitution. He classified constitution with pathogenesis grounding in body formal distinction, flesh hardness and softness, face color and form, skin color. Therefore he grasped the rule of constitution connected with physiological function and pathological distinction, applied the rule of constitution in the diagnosis and cure of the chronic & epidemic febrile disease.

Experimental Study on the Heat Shielding Performance of Lightweight Foamed Concrete Using EPS beads. (EPS 비드를 사용한 경량기포콘크리트의 차열성능의 실험적 연구)

  • Hong, Snag-Hun;Song, Seung-Li;You, Nam-Gyu;Jung, Ui-In;Kim, Bong-Joo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2018.05a
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    • pp.21-22
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    • 2018
  • Foamed concrete is a porous concrete that is cured by mixing bubbles into cement slurry. It is lighter than ordinary concrete and is characterized by higher insulation. Lightweight foamed concerte is mainly used as a sandwich panel in Korea, and is also used as a refractory filler in fireproof safes. Studies on lightwight foamed concrete have been carried out on strength,density and thermal conductivity. However, it is confirmed that the research on the fire resistance performance is very limited. Based on this study, fire resistance of lightweight foamed concrete using expanded polystyrene beads is investigated.

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Biofilm-forming ability and adherence to poly-(methyl-methacrylate) acrylic resin materials of oral Candida albicans strains isolated from HIV positive subjects

  • Uzunoglu, Emel;Bicer, Arzu Zeynep Yildirim;Dolapci, Istar;Dogan, Arife
    • The Journal of Advanced Prosthodontics
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    • v.6 no.1
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    • pp.30-34
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    • 2014
  • PURPOSE. This study evaluated the adhesion to acrylic resin specimens and biofilm formation capability of Candida albicans strains isolated from HIV positive subjects' oral rinse solutions. MATERIALS AND METHODS. The material tested was a heat-cured acrylic resin (Acron Duo). Using the adhesion and crystal violet assays, 14 oral Candida albicans isolated from HIV-positive subjects and 2 references Candida strains (C. albicans ATCC 90028 and C. albicans ATCC 90128) were compared for their biofilm production and adhesion properties to acrylic surfaces in vitro. RESULTS. There were no significant differences in adhesion (P=.52) and biofilm formation assays (P=.42) by statistical analysis with Mann-Whitney test. CONCLUSION. Denture stomatitis and increased prevalence of candidal carriage in HIV infected patients is unlikely to be related to the biofilm formation and adhesion abilities of C. albicans to acrylic resin materials.

One case report of Expoliative Dermatitis due to Psoriasis (건선으로 인한 박탈피부염 환자 치험 1례)

  • Park, Owe-suk;Kim, Yoon-bum
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.17 no.3
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    • pp.131-137
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    • 2004
  • In clinical practice, Psoriasis is commomly difficult to be completely cured that only repeats improvement and to be worsen. We experienced one case of Psoriasis patient who had had generalized expoliative Psoriasis for more than one year. After hospitalization treatment of ten days and outpatient treatment of three months, he's chief complain improved continuously and there was not worsen sign any more. So, He could return to his usual life, We still did't know the mechanism that Saengkankunbi-Tang brought his improvement by, but we think that more case studies are necessary focusing on damp-heat because of much drinking for long time and years of duration of skin disease.

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Development of mix design method for geopolymer concrete

  • Parveen, Parveen;Singhal, Dhirendra
    • Advances in concrete construction
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    • v.5 no.4
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    • pp.377-390
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    • 2017
  • This study proposes a mix design method for geopolymer concrete (GPC) using low calcium fly ash and alccofine, with the focus on achieving the required compressive strength and workability at heat and ambient curing. Key factors identified and nine mixes with varied fly ash content (350, 375 and $400kg/m^3$) and different molarity (8, 12 and 16M) of NaOH solutions were prepared. The cubes prepared were cured at different temperatures ($27^{\circ}C$, $60^{\circ}C$ and $90^{\circ}C$) and tested for its compressive strength after 3, 7 and 28 days of curing. Fly ash content has been considered as the direct measure of workability and strength. The suggested mix design approach has been verified with the help of the example and targets well the requirements of fresh and hardened concrete.

Preparation of Spacer for Safety Improvement of Architecture (건축물의 안전성 향상을 위한 Spacer의 제조)

  • 홍성수;강기준;한지원
    • Journal of the Korean Society of Safety
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    • v.13 no.3
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    • pp.45-50
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    • 1998
  • The low grade domestic kaoline, such as pink-C and white-D, was converted to metakaoline, which has pozzolanic reactivity by heat treatment in the temperature range of $600^{\circ}C$ to 100$0^{\circ}C$ for preparing the spacer. The spacer was used for supporting the reinforced steel rod during construction to improve the safety of architecture. Pink-C and white-D were completely dehydroxylated when burnt at 80$0^{\circ}C$ for 1 hour and converted to metakaoline. The compressive strengths of specimens added calcined pink-C were lower than those of press molding mortar products inspite of calcining conditions. When white-D with calcined 80$0^{\circ}C$ and 100$0^{\circ}C$ for 1 hour was mixed 30% in the weight ratio of cement, the specimens cured 28 days had 338 $kg/cm^2$ and 347 $kg/cm^2$ of compressive strengths, respectively.

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Active components delivery rate from acrylic resin maxillary surgical obturator: Part I

  • Al-Kaabi, Arshad;Hamid, Mohammed A.
    • Advances in materials Research
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    • v.9 no.2
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    • pp.109-114
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    • 2020
  • The purpose of this study was to observe the trend of compounds release from acrylic resin oral prosthesis when used for drug delivery as well as a restoration. In this study, 10 specimens of heat-cured polymethylmethacrylate material were prepared and loaded with methylene blue biological stain. The specimens were then submerged in vials with 5 ml distilled water for 24 hours. The extraction procedure continued for 4 days, each day the specimens were immersed in another 5 ml distilled water vial. All extracted solutions were analyzed by visible light spectroscopy for absorbance comparison. The statistical results showed that the absorbance values were significantly different in the first day of extraction than the following days. However, there was no statistical difference among the 2nd, 3rd and 4th days of extraction. Biological stain loading to acrylic resin at the mixing stage, and then after extraction in distilled water, showed a burst release during the first day followed by a constant release during the following few days.