• Journal of Conservation Science
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• v.25 no.4
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• pp.439-450
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• 2009

The purpose of this study is to find out characteristics of the fillers made by epoxy resin (L-30) and filling epoxy resin (L-50) with talc, quartz sand and wollastonite with different mixture ratio of 5%, 50%, 80%, 120%, and 150%. The viscometer and colorimeter were used to measure the viscosity and chromaticity of the fillers. Additionally, IC and SEM were used to reveal characteristics of the filler, and checked ultrasonic wave velocity, compressive strength and contact angle to estimate the stability between the filler and stones which are essential for conservation treatments. The filler mixed with the talc had the lowest value in the ultrasonic wave velocity analysis, and its compressive strength decreased as the mixing rate of talc increased. On the other hand, wollastonite had higher values than others in the ultrasonic wave velocity and the compressive strength regardless of epoxy resin type, also, these values increased as mixing rate increased. The properties of the filler, which include the granularity and shape, have influence on characteristics of the stone conservation adhesives. Thus, the filler type, characteristic, and mixture ratio must be considered for effective conservation treatment.

• Composites Research
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• v.24 no.5
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• pp.34-38
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• 2011

Carbon nanotubes (CNTs) have been widely investigated as reinforcements of CNT/polymer nanocomposites to enhance mechanical and electrical properties of polymer matrices since their discovery in the early 90's. Furthermore, the number of studies about incorporating CNTs into carbon fiber reinforced plastics (CFRP) to reinforce their polymer matrices is increasing recently. In this study, single-walled carbon nanotubes (SWNT) were dispersed in epoxy with 0.2 wt.% and 0.5 wt.%. Then, the SWNT/epoxy mixtures were processed to carbon fiber composites by a vacuum assisted resin transfer molding (VARTM) and a wet lay up method. The processed composite samples were tested for the interlaminar shear strength (ILSS). The relationship between the interlaminar shear strengths and processing, and the reinforcement mechanism of carbon nanotubes were investigated. CNT/epoxy nanocomposite specimens showed the increased tensile properties. However, the ILSS of carbon fiber composites was not enhanced by reinforcing the matrix with CNTs because of processing issues caused by increased viscosity of the matrix due to addition of CNTs particularly for a VARTM method.

• Journal of Conservation Science
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• v.28 no.2
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• pp.131-139
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• 2012

The exothermic cure kinetics of epoxy resin was controlled by hardener containing fast and slow curing agents. The epoxy risen comprises hydrogenated bisphenol A-based epoxide (HBA), fast curing agent (FH) and slow curing agent poly(propyleneglycol)bis(2-aminopropylether) (SH). Talc was used as an inorganic additive. In the process of curing, cure kinetics along with temperature was monitored by differential scanning calorimeter (DSC) and thermocouple to show that the temperature increase was well controlled by adjusting the hardener mixture. Additionally, bending and tensile strengths of the epoxy/talc composites were also measured to be lower and higher with the amount of the talc inorganic additive, respectively. It is thus concluded that the increase in the temperature during exothermic curing reaction and mechanical properties of epoxy resins are tuned by optimizing hardener mixture for successful stone conservation.

• Applied Chemistry for Engineering
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• v.10 no.2
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• pp.218-224
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• 1999

Continuous ion exchange characteristics of the synthetic coolant contained Ni, Co and Ag ions of low concentration in acidic-oxidizing conditions have been studied to suggest the guideline for the optimum operation of mixed-bed demincralizer during the shutdown period of a pressurized water reactor (PWR). In the effect of the form of cation resins on the removal capacity of metal ions, the performance of a $H^+$-form resin was about 6% higher than that of a $Li^+$-form resin. Mixed-bed of cation and anion resins in comparison with nonmixed-bed of them, had no affected on the removal capacity of metal ions but very slightly increased the slope of breakthrough curves of metal ions. In the effect related to acidic-oxidizing conditions of the coolant, the addition of boric acid very slightly decreased the slope of breakthrough curves of metal ions, while the addition of hydrogen peroxide slightly decreased the removal capacity of metal ions.

• Journal of Korea Foresty Energy
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• v.24 no.1
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• pp.28-32
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• 2005

This study was performed to find a new use of wood tar from the manufacturing process of wood charcoal. Plywoods made of phenol adhesives mixed with wood tar were manufactured, and physical, mechanical properties and formaldehyde emission were investigated. Plywoods made of phenol adhesives mixed with wood tar were almost same as an original phenol adhesive in physical and mechanical properties and tensile-shear adhesive strength of the plywood was higher than the original one in both non-waterproof and waterproof tests. Formaldehyde emission was lower as the amount of wood tar increased in phenol adhesive.

• Applied Chemistry for Engineering
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• v.27 no.6
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• pp.633-638
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• 2016

In this study, we used three kinds of commercially available cation, anion, and mixed-ion exchange resins to separate radioactive ions from a polluted water containing Cs, I, and other radioactive ions. The experiment was conducted at a room temperature with a batch method, and a comparative analysis on the decontamination ability of each resin for the removal of Cs and I was performed by using different quantities of resins. The concentration was analyzed using ion chromatography and the ion exchange resin product from company D showed an overall high ion exchange ability. However, for most of the experiments when the amount of ion exchange resin was decreased, the decontamination ability of the resins against mass increased. When the mass of company D's cation exchange resin was small, the ion exchange ability against Cs and I ions were measured as 0.199 and 0.344 meq/g, respectively. When the mixed ion exchange resin was used, the ion exchange ability against I ions was measured as 0.33 meq/g. All in all, company D's ion exchange resins exhibited a relatively higher ion exchange ability particularly against I ions than that of other companies' exchange ions.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.11
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• pp.2374-2382
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• 2002

Aluminum alloy/aramid fiber reinforced plastic(Al/AFRP) laminates consists of high strength metal(A15052) and laminated aramid fiber with structural adhesive bond. The mixture ratio effect of epoxy resin curing agent accelerator on the tensile strength and T-peel strength characteristic in Al AFRP laminates were investigated in this study. The epoxy. diglycidylether of bisphenol A(DCEBA), It'as cured by methylene dianiline(MDA) with or without an accelerator(K-54). Eight different kinds of resin mixture ratios were selected for the test , five kinds of Al/AFRP laminates were named as Al/AFRP(1) and three others of Al/AFRP laminates were named as Al/AFRP(2). The comparison of tensile strength and T-peel strength with variation of resin mixture ratio were studied. Respectively. Al/AFRP(1) and Al/AFRP(2) indicated approximately 6.0 times and 7.0 times more improved maximum tensile strength in comparison with those of monolithic A15052. Al/AFRP(2) indicated approximately 1.5 times more impoved maximum T-peel strengths in comparison with those of Al/AFRP(1). As results. Al/AFRP(2) turned out to have more effective characteristics on the tensile strength and T-peel strength than those of Al/AFRP(1).

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.649-650
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• 2013

• Proceedings of the Korean Nuclear Society Conference
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• 1995.05b
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• pp.921-927
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• 1995

수지충전식 전해재생조내에서 바나듐-철-Picolinate 착화물이 함유된 모의 LOMI 제염폐액의 재생거동에 대한 공정변수의 영향을 조사하였다. 전기투석에 의해 양이온종이 제염 폐액으로부터 제거되는 재생 분리효율에 대한 전류밀도, 제염폐액 공급유량 및 재생조내 수지층두께 등 공정변수의 영향은 바나듐이온이 가장 크게 받는다. 공정변수의 영향을 총괄 파라미터인 공정변수비 $\alpha$로 정의하여 나타낼 때 재생 분리효율 95%이상을 얻기 위해서는 $\alpha$가 0.2 이하로 유지되어야 한다. LOMI 제염폐액의 재생시 전기투석 flux는 공정변수비, $\alpha$값이 증가함에 따라 철이온이 바나듐이온에 비해 더욱 커지는 경향을 보였다. 재생종료 후 발생되는 음극폐액내 철 및 코발트 등 방사성이온종은 음극액의 초기 수소이온 농도를 조절하면 침전제의 첨가 얼이 음극반응에 의해 음극액의 pH를 산성에서 알카리성으로 바꿀 수 있어, 수산화물 형태의 침전물 입자로 만들어 쉽게 제거할 수 있다. 재생시 바나듐이온은 대부분 $V^{III}$(Pic)$_2$$^{+}$ 착화물형태로 전기투석된다. 음극액으로 formate용액을 사용하면 철 및 코발트 등 방사성이온종을 제거한 음극액은 농축된 LOMI제염제로 회수하여 필요시 산화가를 조정한 후 재생된 착화제와 혼합하여 제염제로 재사용할 수 있어, 더욱 효과적으로 제염폐액을 재생하는 향상된 재생방법이다.다.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.2 no.3
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• pp.165-174
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• 2004

In order to simultaneously vitrify the ion exchange resin(IER) and combustible dry active waste(DAW) generated from Korean nuclear power plants, a vitrification pilot test was conducted using an induction cold crucible melter(CCM) . The energy necessary for startup of the glass using a Ti-ring was evaluated as about 290 kWh. The power supplied from a high frequency generator to melt the glass properly was ranged from 160 to 190 kW without any interruption. When the mixture of the IER and DAW was fed into the CCM, the concentration of CO was lowered up to 1/40 compared to feeding the IER solely. It may be caused by the DAW which can produce about 1.8 times higher heat compared to the IER. When the swelling phenomenon occurred in the glass melt, the concentration of $NO_2$, oxidizing gas, was higher than NO, reducing gas. Total feed amounts of the IER and DAW were 368 and 751 kg, respectively. And then, about 74 of volume reduction factor was achieved.