• Title/Summary/Keyword: water curing temperature

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AN EXPERIMENTAL STUDY ON THE DIMENSIONAL CHANGES OF RELINED DENTURES AND MECHANICAL PROPERTIES AND SURFACE TEXTURES OF SEVERAL RESINS USED IN DENTURE RELINING (수종 레진으로 의치상 조직면 개조시 의치상의 크기변화와 물리적 성질 및 표면상태 비교 연구)

  • Lee, Chang-Han;Kim, Yung-Soo
    • The Journal of Korean Academy of Prosthodontics
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    • v.28 no.1
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    • pp.25-41
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    • 1990
  • The purpose of this study was to evaluate and compare the dimensional changes of relined dentures with a light-curing resin, a heat-curing resin, and a direct, hard reline resin. And also to measure the transverse strength, impact strength, surface hardness of the three resins used in relining. The surface textures of three resins also of evaluated by using scanning electron microscope. Through analyses on the data from this study, the following conclusions were obtained. 1. Impact strength of heat-curing resin was highest, and direct, hard reline resin higher, light-curing resin lowest. 2. Transverse strength of heat-curing resin was highest, and direct, hard reline resin and light-curing resin was lower and not signiicantly different. 3. Surface hardness of light-curing resin was lighest, heat-curing resin higher, and direct, hard reline resin was lowest. 4. After storage of the relined dentures for 1 day and 1 week in water at room temperature, linear shrinkage of distance between the reference points in the maxillary base relined with direct, hard reline resin was lowest, and those relined with light-curing resin and heat-curing resin were lower and were not significantly different. 5. After storage for 4 weeks in orator at room tempeature, linear shrinkage of distance between ridge crests of dentures relined with heat-curing resin was highest and that of distance between denture borders was not significantly different. 6. The dimensional changes of relined dentures during storage in water was not significant except those of distance between denture borders relined with light-curing resin at 1 day and 1 week storage in water. 7. At low magnification (x40) of SEM examination, the surface textures of three resins were similar except light-curing resin which had some defects. At high magnification (x200), the surface textures of hard, direct reline resin were smooth with little defects, but those of heat-curing resin and light-curing resin w ere irregular.

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Strength Properties by Curing Temperature of High Volume Fly-Ash Concrete (플라이애쉬를 다량 치환한 콘크리트의 양생온도에 따른 강도성상)

  • 이동하;정근호;백민수;김성식;임남기;정상진
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2002.11a
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    • pp.63-66
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    • 2002
  • In this study, it does a high volume flyash substituted concrete experiments in two curing temperature circumstances - 35$^{\circ}C$, 2$0^{\circ}C$. High volume flyash concrete is tested in fresh concrete properties and hardeded concrete properties. In the fresh concrete test items, there is slump, air contents, concrete setting tests. 3, 7, and 28 days water curing compressive strength is measured in the hardened concrete test. The purpose of this study is to submit a various flyash concrete data for application to field. The result of this study is that the best strength is developed at the plain concrete cured 2$0^{\circ}C$ and Mixing F43 shows the best strength among specimens which cured at 35$^{\circ}C$

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An Experimental Study on the Strength Development of Fly-Ash Mortar by Using the Activator and Curing Temperature change. (자극제 사용 및 양생온도 변화에 의한 플라이애쉬 모르타르의 강도발현에 관한 실험적 연구)

  • 배수환;최광윤;정재동;최영화
    • Proceedings of the Korea Concrete Institute Conference
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    • 2003.11a
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    • pp.277-280
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    • 2003
  • The purpose of this study is for the active use of the fly ash, which is a by-product of the combustion pulverizes coal thermal power plants, to compensate for the lack of landfill and for conservation of energy, by using fly ash as the supplementary cementitious material, and to prove its possibility as the related products of the cement. First of all, we examined strength development of Micro grinding fly ash by elevating its fineness and using $Na_{2}SO_{4}$ as an activator to elevate pozzolanic reaction of fly ash. Following fly ash replacement ratio and curing temperature we hope to prove its properties to suggest its possibility in the concrete and cement industry. In case of water curing, the more fineness and higher annexing of activator is, the higher strength is, and the higher curing temperature is the more pozzolanic reaction happens.

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Preparation and Properties of Crosslinkable Waterborne Polyurethanes Containing Aminoplast -Effect of Curing Condition-

  • Kwon Ji-Yun;Rahman Mohammad Mizanur;Kim Han-Do
    • Fibers and Polymers
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    • v.7 no.2
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    • pp.95-104
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    • 2006
  • In order to improve the water swelling, thermal/mechanical and adhesion properties of waterborne polyurethane (WBPU), a series of the crosslinkable WBPUs containing hydrophilic ionic component, dimethylol propionic acid (20 mole%), were prepared by in-situ polymerization using a cross-linker hexakis (methoxymethyl) melamine (HMMM). Effects of the HMMM content (2, 4, and 6 wt%) and curing temperature on these properties of the crosslinked WBPUs samples were investigated. All properties were found to increase with increasing HMMM content. It was found that the optimum curing temperature of the WBPU films and adhesives was near $120^{\circ}C$, which was not dependent on the HMMM content.

A Study on the Properties of Epoxy Based Powder Coating with Various Curing Agents (에폭시 분체도료의 경화제 종류에 따른 물성에 관한 연구)

  • Park, Jae-Hong;Shin, Young-Jo
    • Applied Chemistry for Engineering
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    • v.9 no.1
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    • pp.58-65
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    • 1998
  • Substituted dicyandiamide(Sub-DICY), Accelerated dicyandiamide(Acc-DICY), Trimellitic anhydride(TMA), Pyromellitic dianhydride(PMDA) and Phenolic curing agent(Ph.C.A.) are mainly used for epoxy powder coating curing agent. Various characteristics of epoxy films fully cured by optimum condition such as mechanical properties like $T_g$, tensile strength, elongation at break hardness, abrasion resistance and chemical properties like water absorption, acid resistance, alkali resistance and electrical properties, corrosion resistance are determined by various measuring devices and analyses devices. In conclusion, phenolic curing agent was shown excellent thoughness but severe color change as temperature increased. Acid anhydride has excellent insulation properties and color stability at elevated temperature but lower thoughness and adhesion to substrate. DICY curing agent was shown high water absorption and severe color chance as temperature increased.

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Effects of Curing Temperature and Times on Chemical Properties and Palatability of Cured Boiled Pork Loins (염지 온도와 기간이 삶은 돼지고기 등심의 이화학적 특성과 기호성에 미치는 영향)

  • 현재석;강희곤;김미숙;정인철;문윤희
    • Food Science of Animal Resources
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    • v.23 no.1
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    • pp.32-38
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    • 2003
  • The effects of curing temperatures(1, 5 and 10$^{\circ}C$) and times on the chemical properties and palatability of cured pork loins which were cured in the 7% curing solution were investigated. The pork loins cured at 10$^{\circ}C$ curing temperature showed the decreased level of pH and water holding capacity up to 15 days of curing time. The growth of bacteria in the curing solution and surface region of cured loins, cured at 10$^{\circ}C$ were rapid after 12 days of curing. However, bacteria were not detected(<0.05${\times}$10$^2$ CFU/g) in the central region of cured loin until 15 days of curing. The penetration of salt into the central region of cured loins was faster at 10$^{\circ}C$ curing temperature than at lower curing temperatures for all curing times. The difference of salt contents between surface and central regions in the cured loins was less at higher temperature than at lower temperatures, and the difference decreased in boiling process for all curing times. The color fixation of the cured boiled loins was better at 5 and 10$^{\circ}C$ curing temperatures than at 1$^{\circ}C$. The sensory scores for saltiness and flavor of the cured boiled pork loins were higher at higher temperature than at lower temperatures until 9∼12 days of curing. Palatable cured boiled pork loins could be produced under the curing solution at low temperatures of 1 and 5$^{\circ}C$ for 12 and 9 days, respectively.

Effect of temperature on the behavior of self-compacting concretes and their durability

  • Salhi, M.;Li, A.;Ghrici, M.;Bliard, C.
    • Advances in concrete construction
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    • v.7 no.4
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    • pp.277-288
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    • 2019
  • The formulation of self-compacting concretes (SCC) and the study of their properties at the laboratory level were currently well mastered. The aim of this work is to characterize SCC under hot climatic conditions and their effects on the properties of fresh and hardened SCC. Particularly, the effect of the initial wet curing time on the mechanical behavior such as the compressive strength and the durability of the SCCs (acid and sulfate attack) as well as the microstructure of SCCs mixtures. In this study, we used two types of cement, Portland cement and slag cement, three water/binder (W/B) ratio (0.32, 0.38 and 0.44) and five curing modes. The obtained results shows that the compressive strength is strongly influenced by the curing methods, 7-days of curing in the water and then followed by a maturing in a hot climate was the optimal duration for the development of a better compressive strength, regardless of the type of binder and the W/B ratio.

Crosslinking of PVA Films with BTCA (BTCA를 이용한 PVA 필름의 가교에 대한 연구)

  • Yun, Seong-Jong;Heo, Yong-Chan;Jang, Jin-Ho
    • Proceedings of the Korean Society of Dyers and Finishers Conference
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    • 2008.04a
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    • pp.135-137
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    • 2008
  • PVA films with 1,2,3,4-Butanetetracarboxylic acid(BTCA) and sodium hypophosphite monohydrate(SHM) were crosslinked via thermal curing. Different parameters affecting on the crosslinking were investigated including BTCA and SHM concentration, curing temperature and time. The cured films was extracted with boiling water and gel fraction was calculated from weight change of the PVA films. Moisture regain of the gelled films was also measured. While the gel fraction of PVA films increased with increasing curing temperature and time, moisture regain decreased. Water resistance of the crosslinked PVA films improved by the BTCA crosslinking treatment.

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The Improvement of Surface Layer Using Cement-hardening Agents in Dredged and Reclaimed Marine Clay (준설매립된 해성점성토에서 시멘트계 고화재를 이용한 표층개량)

  • NAM JUNG-MAN;YUN JUNG-MANN
    • Journal of Ocean Engineering and Technology
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    • v.18 no.4 s.59
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    • pp.46-51
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    • 2004
  • The surface layer in dredged and reclaimed marine clay is improved by mixing of shallow soils and hardening agents, which is made of cement, containing some other special admixtures. Tests in both laboratory and field settings are performed to investigate the improvement effect and strength properties of cement-stabilized soils. The test results show that the hardening agent sufficiently improves the soil properties of the surface layer, while increasing the load-carrying capacity. The strength of cement-stabilized soils depends, primarily, on water-to-cement ratio and curing temperature. That is, the higher curing temperature and the longer curing time, the higher the strength in cement-stabilized soils. The high ratio of water-ta-cement results in a lower strength.

Effect of Compressive Strength and Curing Condition on the Direct Tensile Strength Properties of Ultra High Performance Concrete (압축강도 및 양생조건에 따른 초고성능 콘크리트의 직접인장강도 특성)

  • Park, Ji Woong;Lee, Gun Cheol
    • Journal of the Korea Institute of Building Construction
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    • v.17 no.2
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    • pp.175-181
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    • 2017
  • The purpose of this study is evaluating the characteristics of tensile strength of UHPC and examining tensile performance of notched specimens by direct tensile test. For test variables, 120, 150, and 180MPa of target design standard strength were aimed at. With general water curing and $90^{\circ}C$ high temperature steam as curing conditions, the properties were reviewed. Overall, it was represented that the specimens of notch-type direct tensile strength concrete was effective in inducing central cracks compared with existing direct tension specimens. Through this, it was judged that data construction with high reliability was possible. Above all, in a graph of direct tensile strength and strain, in the case of steam curing at high temperature, there was great difference of initial tensile strength compared with water curing. As passing of ages, an aspect that the difference gradually decreased was shown. Maximum tensile strength was found to increase steadily with increasing age for all target design strengths in water curing, in the case of steam curing, the tendency to increase significantly due to the initial strength development effect at 7 days of age. The initial crack strength increases with age in case of underwater curing, in the case of steam curing, it was higher than that of water curing in 7 days, while the strength of 28 days was lowered. In this part, it is considered necessary to examine the arrangement condition of the steel fiber.