• Journal of Dental Rehabilitation and Applied Science
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• v.26 no.3
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• pp.273-283
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• 2010

This study evaluated the effect of 3 different compatible screws on the detorque values in a multiple implant-supported superstructure and single implant abutments. An implant superstructure directly connected to 4 implants was screwed to 6 experimental dental stone casts made by acrylic resin splinted impressions, using 20 Ncm. The detorque values of screws were measured twice. Three compatible abutment screws used in this study were TorqTite screw, Gold-Tite screw, and, Titanium screw. And, using single implant abutments (GoldAdapt Engaging abutments), the detorque values of 3 different screws were measured twice on 2 implants of 5 experimental casts. According to statistical analysis of detorque values using mixed model at a .05 level of significance, no statistically significant differences among 3 different compatible screws were found in a multiple implant-supported superstructure (p>0.05). But, in single implant abutments, statistically significant differences among 3 different compatible screws were found (p=0.0175). The detorque values of TorqTite(p=0.0462) and Titanium(p=0.0348) screws were significantly higher than those of Gold-Tite screw, but no statisticantly significantlydifferences were found between TorqTite and Titanium screws(p>0.05). Therefore, various compatible screws showed significant effects on the detorque values for single implant abutment, but, showed no significant effects for a multiple implant-supported superstructure.

• Journal of Conservation Science
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• v.36 no.5
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• pp.383-392
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• 2020

This study aimed to examine the characteristics of paint used for modern art works by conducting sectional observations, inorganic component analysis, and infrared spectroscopic analysis on the painted layers of 3 painted sculpture works exhibited in the Yongdam Dam Environmental Sculpture Park and Naejangsan Sculpture Park in the Jeollabuk-do area. The observations indicate that the cross section is composed of various layers of 2-3 folds, the thickness of the layers was uneven at approximately 23-150 ㎛, and putty was used for plate treatment prior to painting. Inorganic component analysis results show that putty containing calcium carbonate, iron oxide, diatomite, and titanium dioxide was used for the putty layer. It is also assumed that paint mixed with green (Cr₂O₃), blue(sodaliteblue), red(chromered), andwhite(TiO₂) colors were used for the painted layers. As a result of infrared spectroscopic analysis to confirm the types of paint, it is estimated that the paint was mixed with polyester resin and an extender.

• Journal of the Korean Ceramic Society
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• v.38 no.9
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• pp.839-845
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• 2001

In order to vitrify the Ion-Exchange Resin(IER), Dry Active Waste(DAW), and borate concentrate generated from the commercial nuclear facilities, the glass formulation study based on the their compositions was performed. Two glasses named as RG-1 and DG-1 were formulated as the candidate glasses for the vitrification of hte IER and DAW, respectively. A glass named as MG-1 was also formulated as a candidate glass for the vitrification of the mixed wastes containing the IER, DAW, and borate concentrate. The process parameters, product qualities, and economics were evaluated for the candidate glasses and confirmed experimentally for the some properties. The glass viscosity and electrical conductivity as the process parameters were in the desired ranges. the product qualities such as glass density, chemical durability, phase stability, etc. were satisfactory. In case of vitrifying the wastes using our developed glass formulation study, the volume reduction factors for the IER, DAW and mixed wastes were evaluated as 21, 89 and 75, respectively.

• Journal of the Korean Wood Science and Technology
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• v.49 no.4
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• pp.315-327
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• 2021

Purpose of this study is reviewing the use method for the sawdust (sawmilling by-product) and rice husk (Agriculture by-product) by adding charcoal, an eco-friendly material. Mixed composite boards were manufactured with those materials with each density and mixing ratio, and bending performance was investigated. When the addition ratio of sawdust, rice husk and charcoal is 50:20:20 and the resin addition ratio is 10%, as the density of the prepared mixed board ranges from 0.5 g/cm³ to 0.7 g/cm³, the bending strength was 0.42~3.24 N/mm², dynamic modulus of elasticity was 94.5~888.4 N/mm², and the static modulus of elasticity was in the range of 31.4~220.7 N/mm². As the density increased, the bending performance increased, indicating that the density had a significant effect on the bending performance. In a board prepared by setting the density of 0.6 g/cm³, the addition ratio of sawdust to 50%, and the addition ratio of rice husk and charcoal at different ratios, the bending performance showed a tendency to decrease as the addition ratio of charcoal increased. The relationship between the addition ratio of rice husk and charcoal, bending strength, resonance frequency, and dynamic and static bending modulus showed a rather low correlation with the values of the coefficient of determination (R²) of 0.4562, 0.4310, 0.4589, and 0.5847, respectively. Thus, we found that the effect of the addition ratio on the bending performance was small.

• Journal of Environmental Impact Assessment
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• v.32 no.6
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• pp.431-436
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• 2023

As the industry develops, the amount of heavy metals flowing into the ecosystem is increasing. Heavy metals are difficult to decompose and remain in the ecosystem for a long time and cause toxicity, which is removed by physicochemical methods such as adsorption, filtration, and chemical precipitation during water treatment. In this study, Alginate bead was selected as a chelating resin for adsorbing and removing heavy metals, and the Jellyfish Extract at Immunity reaction (JEI) were mixed to evaluate the adsorption efficiency of heavy metals accordingly. beads mixed with JEI showed high adsorption efficiency in lead (79-99%) and copper (64-70%) according to the characteristics of Alginate, and low adsorption efficiency in cadmium (25-37%) and zinc (5-6%). Although heavy metal adsorption did not increase in proportion to the content of JEI, 50% and 100% JEI beads showed significant increases. As a result of applying the reaction rate equation, it was found that it was more suitable for the pseudo-secondary reaction equation than the pseudo-first reaction equation.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.06a
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• pp.158-166
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• 2004

The optimal conditions are obtained for the decomposition of solid radioactive wastes, including ion exchange resin, zeolite, active charcoal, and sludge from nuclear power plant. In the process of decomposing the radioactive wastes were used the microwave acid digestion method with mixed acid. The solution after acid digestion by the following method was colorless and transparent. Each solution was analyzed with ICP-AES and AAS and the recovery yield for 5 different elements added the simulated radioactive wastes were over 94%. As an effective pre-treatment, the proposed microwave acid digestion conditions concerning the chemical trait of each radioactive waste are expected to be generally applied to above-mentioned radioactive wastes from nuclear power plant hereafter.

• Asian Journal of Turfgrass Science
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• v.18 no.2
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• pp.77-95
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• 2004

This study was conducted to find out definition, specification and characteristics of water-proof method for pond at golf courses that located in the mountain in Korea. Water-proof method of pond was selected by location, kind of soil, area, depth, cost, construction period and so on. 1. Soil Bentonite Sealing Liner(SBL) is to mix soil with a good quality bentonite. Then the mixed material was dressed on the bottom of pond. $\\$Merit of SBL is to purify the water and planting is possible. It can also reduce construction period and is economical. It's easy to find out the leak points. Demerit of SBL is expensive, if good quality soil is not in constructing site. Shape of pond edge is simple. 2. Ethylen Propylene Diene Monomer Sheef(EPDM-Sheet) makes use of sheet that resists to acid and alkaline. EPDM-Sheet spreads out as a mat on the pond for water-proof. Merit of EPDM-Sheet is to perfectly prove water and make a diverse shape of pond edge. Demerit of EPDM-Sheet is not friendly to environment. It needs drain system, air ventilation and long period of construction. It is also difficult to find out leaking points in this method. 3. Water proof of ESS-13 uses ESS-13 that is resin of vegetable matter and friendly to environment. To prove water of pond, ESS-13 is delicate with water in the pond. After that, Ess-13 in the water is expanded at pore space in the soil and cover with soil. ESS-13 can be to prove a leaking pond in golf course under business. ESS-13 is cheap and it needs short construction period. It does not need to switch the old water-proof system, additionally. It needs to move fishes to other place before utilizing ESS-13.

• Journal of the Korean Ceramic Society
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• v.39 no.6
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• pp.576-581
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• 2002

In order to simultaneously vitrify the ton Exchange Resin(IER) and Dry Active Waste(DAW) generated from the Nuclear Power Plants, a vitrification pilot test was conducted using an induction cold crucible melter. The PCT result evaluating the chemical durability of the vitrified from showed that the final glass was more durable than the benchmark glass. Liquidus temperature for the final vitrified form was 1048 K(775$\^{C}$) fur heat treatment experiments. The value of the compressive strength for the vitrified form was ninety times higher than the regulation limit, 34 kg/㎠. The glasses on bottom, middle and top of the CCM were homogeneous with no secondary phase. The precipitation of the magnetic metal phase was able to be avoided by simultaneously fEeding of DAW with IER containing strongly reducing organics. Volume reduction factor of 74 was achieved through the vitrification Pilot test for mixed waste.

• The korean journal of orthodontics
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• v.45 no.4
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• pp.164-170
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• 2015

Objective: The aim of this study was to compare the shear bond strength (SBS) of orthodontic brackets bonded to zirconia surfaces using three different zirconia primers and one silane primer, and subjected to thermocycling. Methods: We designed 10 experimental groups following the surface treatment and thermocycling. The surface was treated with one of the following method: no-primer (NP), Porcelain Conditioner (PC), Z-PRIME Plus (ZP), Monobond Plus (MP) and Zirconia Liner Premium (ZL) (n=20). Then each group was subdivided to non-thermocycled and thermocycled groups (NPT, PC, ZPT, MPT, ZLT) (n=10). Orthodontic brackets were bonded to the specimens using $Transbond^{TM}$ XT Paste and light cured for 15 s at $1,100mW/cm^2$. The SBS was measured at a 1 mm/min crosshead speed. The failure mode was assessed by examination with a stereomicroscope and the amount of bonding resin remaining on the zirconia surface was scored using the modified adhesive remnant index (ARI). Results: The SBS of all experimental groups decreased after thermocycling. Before thermocycling, the SBS was ZL, $ZP{\geq}MP{\geq}PC>NP$ but after thermocycling, the SBS was $ZLT{\geq}MPT{\geq}ZPT>PCT=NPT$ (p > 0.05). For the ARI score, both of the groups lacking primer (NP and NPT) displayed adhesive failure modes, but the groups with zirconia primers (ZP, ZPT, MP, MPT, ZL, and ZLT) were associated with mixed failure modes. Conclusions: Surface treatment with a zirconia primer increases the SBS relative to no-primer or silane primer application between orthodontic brackets and zirconia prostheses.

• Journal of the Korean Wood Science and Technology
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• v.40 no.6
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• pp.418-423
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• 2012

In order to develop the end use of cylindrical laminated veneer lumber (LVL) such as wooden crafts, the water proof-bonding strength, the resistance to abrasion and the surface hardness by painting the surface of LVL were investigated. The study results were as follows; The water proof-bonding strength through 5 cyclic test by boiling in water immersion and drying were favorable without delamination of glue line. Then the formulation of glue was resorcinol resin (100) to hardener of paraformaldehyde (5) by mixed weight percentage. The resistance to abrasion was relatively higher at cross section than tangential section. When tangential section of LVL was painted by UV protection oil, the resistance to abrasion was improved. In case of an cross section of LVL, the higher surface hardness appeared at larch core than radiata pine LVL. Also, in case of an tangential section of LVL, the higher surface hardness appeared at glue line than veneer side.