• Title, Summary, Keyword: pressure curing

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Properties of Flexural Strength of Extrusion Molding Concrete Panel According to the Curing Conditions (양생조건에 따른 압출성형콘크리트 패널의 휨강도 특성)

  • Jung, Eun-Hye;Choi, Hun-Gug;Kim, Jae-Won;Seo, Jung-Pil;Park, Sun-Gyu;Kim, Jin-Man
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.441-444
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    • 2006
  • Extrusion molding concrete panel is cured two times, that is the steam curing at atmospheric pressure and a high-pressure steam curing(autoclaving). Steam curing at atmospheric pressure is done before autoclaving and to acquire the proper strength for treat in process. Though this curing is the important factor on the quality of product and the speed in manufacturing process, it was not evaluated properly so far. Because of ignorance about curing, some engineers even think that the dry curing is better than the steam curing. This study is to investigate the properties of specimen according to variation of curing conditions in the coring chamber such as laboratory scale, pilot plant, and commercial plant. As estimating, in case of steam curing at atmospheric pressure to make extrusion molding concrete panel, moisture curing is better than dry curing and the desirable maximum temperature in curing chamber is about $50^{\circ}C$.

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Effects of the curing pressure on the torsional fatigue characteristics of adhesively bonded joints (경화 압력이 접착 조인트의 비틀림 피로 특성에 미치는 영향)

  • Hwang, Hui-Yun;Kim, Byung-Jung;Lee, Dae-Gil
    • Proceedings of the KSME Conference
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    • pp.196-201
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    • 2004
  • Adhesive joints have been widely used for fastening thin adherends because they can distribute the load over a larger area than mechanical joints, require no hole, add very little weight to the structure and have superior fatigue resistance. However, the fatigue characteristics of adhesive joints are much affected by applied pressure during curing operation because actual curing temperature is changed by applied pressure and the adhesion characteristics of adhesives are very sensitive to manufacturing conditions. In this study, cure monitoring and torsional fatigue tests of adhesive joints with an epoxy adhesive were performed in order to investigate the effects of the applied pressure during curing operation. From the experiments, it was found that the actual curing temperature increased as the applied pressure increased, which increased residual thermal stress in the adhesive layer. Therefore, the fatigue life decreased as the applied pressure increased because the mean stress during fatigue tests increased due to the residual thermal stress.

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A Study on the Curing Bladder Shaping of Tire by Finite Element Method Using Contact Element (접촉요소를 이용한 유한요소법에 의한 타이어 가류브레더 팽창거동에 관한 연구)

  • Kim, Hang-Woo;Hwang, Gab-Woon;Cho, Kyu-Zong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.21 no.3
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    • pp.378-384
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    • 1997
  • In curing process of tire, contact and slip occurs between green tire and curing bladder. The curing process is a critical step in the manufacture of tires. In this investigation, curing bladder shaping is examined using a finite element method. Specifically, a finite element model between the inner part of green tire and the outer part of curing bladder is generated using contact element and curing bladder is generated using incompressible element. Numerical analysis are performed on two different bladder types, different overall outer diameters of curing bladder and different heights of curing bladder. Numerical results show that contact pressure is increased by using toroidal type of curing bladder, increasing overall diameter and increasing height of curing bladder. To obtain natural equilibrium carcass line, there is a requirement in increasing contact pressure of the section between side and bead.

A Study on the Linear Distoration of Self-Curing Resin by Various Curing Technics (다양한 온성방법에 따른 즉시 중합 수지의 선변형에 관한 연구)

  • Lee, Do-Kyung
    • Journal of Technologic Dentistry
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    • v.14 no.1
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    • pp.91-94
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    • 1992
  • This study was made to change dimension of self-curing resin by various curing technics. Specimens were fabricated 45 by 7 curing method. Six measurements(distances AB,BC,CD, AD, AC, and BD) were made of mold section and recorded with micrometer(1/20 mm). The results of the experiment were as follows : 1. The air pressure cured specimens exhibited more distoration than the bench-cured, watercured, and monomer atmosphere-cured specimens(P < 0.05). 2. The water pressure cured specimens exhibited more distoration sphere-cured specimens (P < 0.(15).

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FRACTURE TOUGHNESS OF SELF-CURING DENTURE BASE RESINS WITH DIFFERENT POLYMERIZING CONDITIONS (의치상용 자가중합레진의 중합조건에 따른 파괴인성)

  • Jeong Soo-Yang;Kim Ji-Hye;Yang Byung-Deok;Park Ju-Mi;Song Kwang-Yeob
    • The Journal of Korean Academy of Prosthodontics
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    • v.43 no.1
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    • pp.52-60
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    • 2005
  • Purpose. The intent of this study was to evaluate the effects of curing conditions on self-curing denture base resins to find out proper condition in self-curing resin polymerization. Materials and methods, In this study, 3 commercial self-curing denture base resins are used Vertex SC, Tokuso Rebase and Jet Denture Repair Acrylic. After mixing the self curing resin, it was placed in a stainless steel mold(3$\times$6$\times$60mm). The mold containing the resin was placed under the following conditions: in air at 23$^{\circ}C$; or in water at 23$^{\circ}C$; or in water at 23$^{\circ}C$ under pressure(20psi); or in water at 37$^{\circ}C$ under pressure(20psi) or in water at 50$^{\circ}C$ under pressure(20psi) , or in water at 65$^{\circ}C$ under pressure(20psi), respectively. Also heat-curing denture base resin is polymerized according to manufactures' instructions as control. Fracture toughness was measured by a single edge notched beam(SENB) method. Notch about 3mm deep was carved at the center of the long axis of the specimen using a dental diamond disk driven by a dental micro engine. The flexural test was carried out at a crosshead speed 0.5mm/min and fracture surface were observed under measuring microscope. Results and conclusion . The results obtained were summarized as follows : 1. The fracture toughness value of self-curing denture base resins were relatively lower than that of heat-curing denture base resin. 2. In Vertex SC and Jet Denture Repair Acrylic, higher fracture toughness value was observed in the curing environment with pressure but in Tokuso Rebase, low fracture toughness value was observed but there was no statistical difference. 3. Higher fracture toughness value was observed in the curing environment with water than air but there was no statistical difference. 4. Raising the temperature in water showed the increase of fracture toughness.

Effect of Curing Temperature and Autofrettage Pressure on a Type 3 Cryogenic Propellant Tank (경화온도와 자긴 압력이 Type 3 극저온 추진제 탱크에 미치는 영향 연구)

  • Kang, Sang-Guk;Kim, Myung-Gon;Kong, Cheol-Won;Kim, Chun-Gon
    • Composites Research
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    • v.19 no.4
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    • pp.31-38
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    • 2006
  • In this study, effects of curing temperature and autofrettage pressure on a Type 3 cryogenic propellant tank, which is composed of composite hoop/helical layers and a metal liner, were investigated by thermo elastic analysis and composite/aluminum ring specimen tests. Temperature field of a Type 3 tank was obtained from solving the heat transfer problem and, in turn, was used as nodal temperature boundary conditions during the elastic analyses for curing temperature and autofrettage pressure effects. As a result, it was shown that the higher curing temperature was, the more residual compressive stress and tensile stress were induced in composites and metal liner, respectively. On the contrary, autofrettage pressure brought the reduction of these residual thermal stresses caused by cryogenic environments to the tank structure. This tradeoff for curing temperature and autofrettage pressure must be considered in the design and manufacturing stages for a Type 3 cryogenic tank.

Compressive strength characteristics of cement treated sand prepared by static compaction method

  • Yilmaz, Yuksel;Cetin, Bora;Kahnemouei, Vahid Barzegari
    • Geomechanics and Engineering
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    • v.12 no.6
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    • pp.935-948
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    • 2017
  • An experimental program was conducted to investigate the effects of the static compaction pressure, cement content, water/cement ratio, and curing time on unconfined compressive strength (UCS) of the cement treated sand. UCS were conducted on samples prepared with 4 different cement/sand ratios and were compacted under the lowest and highest static pressures (8 MPa and 40 MPa). Each sample was cured for 7 and 28 days to observe the impact of curing time on UCS of cement treated samples. Results of the study showed the unconfined compressive strength of sand increased as the cement content (5% to 10%) of the cement-sand mixture and compaction pressure (8 MPa to 40 MPa) increased. UCS of sand soil increased 30% to 800% when cement content was increased from 2.5% to 10%. Impact of compaction pressure on UCS decreased with a reduction in cement contents. On the other hand, it was observed that as the water content the cement-sand mixture increased, the unconfined compressive strength showed tendency to decrease regardless of compaction pressure and cement content. When the curing time was extended from 7 days to 28 days, the unconfined compressive strengths of almost all the samples increased approximately by 2 or 3 times.

The Influences of Additives and Curing Temperature on the Expansion Pressure of Calcium Oxide Hydration (생석회의 팽창압 발현에 미치는 첨가제 및 양생온도의 영향)

  • Kim, Won-Ki;Soh, Jeong-Soeb;Kim, Hoon-Sang;Kim, Hong-Joo;Lee, Won-Jun;Shin, Jin-Ho
    • Journal of the Korean Ceramic Society
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    • v.44 no.9
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    • pp.529-535
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    • 2007
  • Calcium oxide has been used as a demolition agent in fracturing rocks and old concrete structures, etc. With the agent, demolition work can be done in safety without a noise, vibration and any other pollution, since high expansive pressure is obtained gradually by only mixing the agents with water and pouring the slurry into boreholes. But application of the non-explosive demolition agent is a time-consuming job, especially in winter. Essentially, this problem is related to the reaction rate of calcium oxide with water. This study examines the influence of additives such as cement and anhydrite on expansion pressure of calcium oxide at different curing temperatures. The expansion pressure of calcium oxide began to increase steadily with the rise of the curing temperature. When mixing calcium oxide alone with water, blown-out shot occurred. But as additives were added to calcium oxide, the reaction of calcium oxide delayed and the expansion pressure showed gradual increment. Especially, anhydrite showed a superior delaying effect than cement on the reaction of calcium oxide.

High Pressure Curing of Phenol Resin for High Quality Coating of Glassy Carbon (고품질 유리질 카본 코팅을 위한 페놀 수지의 고압 경화)

  • Hong, Seok-Gi;Cho, Kwang-Youn;Kwon, Oh-Hyeon;Cho, Yong-Soo;Jang, Seung-Jo
    • Journal of the Korean Ceramic Society
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    • v.48 no.2
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    • pp.141-146
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    • 2011
  • Successful coating of high quality glassy carbon is introduced by applying high pressure during the curing process of dip-coated phenol resin on graphite. The dependence of the applied pressure on the quality of the glassy carbon layer has not been reported so far. Pressure was changed from 0 to 400 psi during curing at $200^{\circ}C$. After carbonized at $1100^{\circ}C$ in inert atmosphere for the 400 psicured sample, as a promising result, a thick (~ 3 mm) and smooth glassy carbon layer could be obtained without any breakage, and the yield of carbonization was remarkably increased. It is believed that the cross-linking of resins results in decreasing volatile contents and, thus, increasing the yield of the glassy carbon. The origin of the improvement is discussed on the basis of several analytical results including FE-SEM, FT-IT and Raman spectrum.

Curing of meat batter by indirect treatment of atmospheric pressure cold plasma

  • Jo, Kyung;Lee, Juri;Lim, Yubong;Hwang, Jaejun;Jung, Samooel
    • Korean Journal of Agricultural Science
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    • v.45 no.1
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    • pp.94-104
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    • 2018
  • Nitrite is an essential additive for cured meat product. Plasma is ionized gas and reactive nitrogen species in plasma can be infused into meat batter and subsequently generate nitrites by reaction with water molecules after plasma treatment. However, the increase of nitrite in meat batter is limited with direct treatment of atmospheric pressure cold plasma because of the increase of meat batter temperature. Therefore, this study investigated the influence of indirect treatment of atmospheric pressure cold plasma on the physicochemical properties of meat batter. Meat batter was indirectly treated with plasma at 1.5 kW for 60 min. The pH of meat batter decreased while the temperature increased with plasma treatment time. The total aerobic bacterial count of meat batter was not affected by plasma treatment. The nitrite content of meat batter was increased to 377.68 mg/kg after 60 min of plasma treatment. The residual nitrite content of cooked meat batter also increased with plasma treatment time. The CIE $a^*$-value of cooked meat batter increased. As plasma treatment time increased, lipid oxidation tended to increase and protein oxidation significantly increased. According to these results, the indirect treatment of atmospheric pressure cold plasma can be used as a new curing method for replacing synthetic nitrite salts.