• Journal of the Korean Society of Industry Convergence
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• v.2 no.2
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• pp.69-72
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• 1999

The aim of this study is to enhance the abrasion of the hydrolyzed polyethylene terephthalate(PET) fabrics by using microwave energy. In other to achieve the aforementioned objectives, PET fabrics were hydrolyzed in NaOH solution by using abrasion method such as dipping, microwave-dipping, pad steam-dry, and pad microwave-dry, and then abrasion of the hydrolyzed PET fabrics was calculated and investigated. As a result obtained form this study, the abrasion of the hydrolyzed PET fabrics is directly proportional to hydrolyzed time and NaOH concentration. And also, microwave-dipping method and pad microwave-dry method showed remarkable abrasion effect than the others.

• KSTLE International Journal
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• v.4 no.1
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• pp.8-13
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• 2003

Abrasion in fretting wear mechanism is studied experimentally with the specimens of two different shapes of spacer grid spring and fuel tubes of a nuclear fuel. Reciprocating sliding wear test has been carried out in the environment of air and water at room temperature. Especially, third body abrasion is referred to for explaining the wear region expansion found during the slip displacement increase with constant normal contact farce. It is found that the expansion behaviour depends on the contact shape. The small clearance between the tube and spring seems to be the preferable region of the wear particle accumulation, which causes third body abrasion of the non-contact area. Even in water environment the third body abrasion occurs apparently. Since the abrasion on the clearance contributes wear volume, the influence of the contact shape on the severity of third body abrasion should be considered to improve the grid spring design in the point of restraining wear damage of a nuclear fuel.

• The Journal of Korean Academy of Prosthodontics
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• v.41 no.5
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• pp.626-639
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• 2003

Statement of problem : Recently, in attempts to reinforce the acrylic resin and to reduce the polymerization shrinkage, it has been reported that adding vinyloligo-silsesquioxane (vinyl-POSS) to PMMA significantly compensates for polymerization shrinkage and somewhat increases the fracture resistance. Purpose : There haven't been any studies on abrasion that can affect the adaptation of the denture in long-term use. In this study abrasion resistance was compared between acrylic resin with vinyl-POSS and commercialized acrylic resin for denture base. In addition, the difference in abrasion resistance according to molding methods was compared. Material and method : Using PaladentR 20 including vinyl-POSS. PaladentR 20, Lucitone 199R, SR IvocapR, denture bases were fabricated using compression molding technique and continuous-pressure injection technique. Surface hardness and abrasion were measured for each group, and the worn surfaces were observed under a scanning electron microscope. Results : 1. When surface hardness was measured for each material and molding technique, there was no statistically significant difference among the materials. (p<0.05) 2. When same denture base material and molding technique were used, the abrasion due to toothpaste solution was 5 times as severe as the abrasion due to soap solution. 3, When toothpaste solution was used, the abrasion decreased in the order of PaladentR20, PaladentR 20 including vinyl-POSS, SR IvocapR, and Lucitone 199R. However statistically significant difference was seen only among PaladentR 20, SR IvocapR, and Lucitone 199R. (p<0.05). 4. When soap solution was used, the abrasion was more severe in PaladentR 20 and including vinyl-POSS PaladentR 20 groups than in SR IvocapR and Lucitone 199R groups. (p<0.05). Conclusion : Addition of vinyl-POSS doesn't improve the abrasion resistance, and the abrasion resistance was similar to those of existing materials. Additional studies under different conditions are needed. For clinical application of vinyl-POSS, further investigations with different requirements and conditions are necessary.

• The Journal of Korean Academy of Prosthodontics
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• v.40 no.2
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• pp.184-192
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• 2002

The purpose of this study was to investigate the abrasion resistance and surface roughness of conventional dental stones and improved dental stones and newly developed dental stones. Materials included in this study were several dental stones and newly developed dental stone; 2 type III. 6 type IV (including newly developed dental stone). 1 type V Ten specimens for each material, total ninety specimens were made. Each specimen was subjected to 50 complete cycle abrasion under constant load 0.42N at speed or 6mm per sec. The depth after abrasion test was measured for each specimen. Surface roughness before and after abrasion test was compared. The results were as follows ; 1. The resin containing die materials such as Tuff Rock and Resin Rock had superior abrasion resistance. 2. Type IV, V dental stone exhibited greater abrasion resistance than Type III dental stone. 3. The results or the surface roughness showed similar pattern with the abrasion resistance.

• Geomechanics and Engineering
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• v.1 no.4
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• pp.323-335
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• 2009

Gravels forming part of the base of flexible pavements experience abrasion and crushing as a result of static and dynamic loads. Abrasion takes place when the sharp corners of the particles of gravel are removed as a result of compressive and shear loads. As a result of abrasion, the particles change in shape. Crushing is caused by the fragmentation of the particles into a mixture of many small particles of varying sizes. In this study, the abrasion and crushing of gravels are evaluated experimentally and analytically. The laboratory component of this study involves gravels that were subjected to abrasion and dynamic compression tests. The evaluation of the abrasion and crushing experienced by the gravel was carried out using fractals. In this study, the fractal dimension concept from fractal theory is used to evaluate: (a) the changes in shape, and (b) the crushing (fragmentation) of the original particles of gravel. It was determined that the fractal dimension of the profile of the particles decreased as a result of abrasion. With respect to crushing, the fragmentation fractal dimension was found to increase with the degree of breakage of the gravel. To understand the influence of crushing on the permeability of the gravels, the hydraulic conductivity of the gravels was measured before and after crushing. The hydraulic conductivity of the gravels was found to decrease with an increase in their level of crushing. Also, changes in the angle of friction of the granular materials as a result of abrasion was calculated using the Krumbein's roundness chart. The angle of friction of the granular materials was found to decrease as a result of abrasion.

• Corrosion Science and Technology
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• v.7 no.6
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• pp.362-369
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• 2008

The impact abrasion behavior of high manganese steel is investigated under three kinds of impact energy in acid hematite ore slurry by using a modified MLD-10 impact abrasion tester. Through the SEM observation of the worn surface and the optical metallographic analysis of the cross-sectional samples, the corrosive impact abrasion mechanisms of the steel under different impact energies are studied. In acid-hematite slurry, the variations of impact energies would result in synchronous transformation of the impact abrasion properties and mechanisms of the high manganese steel in the corrosive condition, as led different corrosive impact abrasion mechanism under different impact energies.

• Textile Coloration and Finishing
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• v.22 no.4
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• pp.373-379
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• 2010

The laboratory inspection and analysis of several types of ropes such as edge tensile test, D/d tensile test and abrasion test were carried out in order to investigate the abrasion degradation by external damage and to obtain the fundamental data for measurement against the abrasion. PET ropes were socketed and evaluated under tensile testing. A yarn-on-yarn abrasion test machine has been developed to study the damage and failure associated with rubbing between fiber surfaces. The abrasion test method consists of sliding a length of interwrapped yarn against itself in a reciprocating fashion, either dry or immersed in liquid. It has also been adapted to measure yarn-on-yarn friction. The influence of spin finish on yarn friction and abrasion was investigated extensively. This study indicates that finish has a major effect not only on yarn performance but also on rope performance under the marine environment.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.3
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• pp.123-133
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• 2018

The purpose of this paper is to propose an experimental method to evaluate the resistance of abrasion about 24 MPa, 27 MPa, and 30 MPa compressive strength. These strength are used in the design and construction of concrete hydraulic structures in Korea. The mixing ratios of the ready mixed concrete strengths were investigated countrywide and set the representative mixture proportion ratios of the nine mixed types of OPC, FA and BFS. After making and curing the test specimens, the underwater abrasion test was performed. ASTM C 1138 International Standard was used to fabricate the test equipment, and the surface abrasion resistance of the specimen was tested using the test equipment. In the case of OPC, the 30% abrasion resistance improvement effect was observed at 72 hours as the water-binder ratio decreased. That was reason the coated cement bond strength of the specimen was strong. In the case of BFS and FA, it was improved by 9.9% and 3.8%, respectively, at 72 hours as the water-binder ratio decreased. It was due to the characteristics of the latent hydraulic and pozzolanic reactions. Generally, the relative abrasion resistance of concrete can be evaluated at 24 hours. However, in case of low strength (under 24 MPa), the surface mortar layer wears much faster at the first 12 hours, so it can be considered to evaluate the relative abrasion loss rate at this point.

• Journal of the Society of Naval Architects of Korea
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• v.56 no.6
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• pp.532-540
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• 2019

This study describes a test method for evaluating the ice friction and abrasion performance of polar coatings. The evaluation methods of physical properties of general coatings for ocean-going vessels and polar coatings for ice-going vessels were investigated and their limitations were analyzed. We have also reviewed previous researches related to the development of polar paints and confirmed the necessity of developing test techniques. A flat steel plate was coated with several types of commercial coating, and cold model ice was used to cause ice friction and abrasion events between coated surface and ice. For evaluation of ice friction and abrasion performances, test procedures such as measurement of coating surface roughness, measurement of frictional force using model ice, implementation of ice abrasion and drying of coating surface were developed. The friction and abrasion characteristics of each coating are analyzed and summarized through the change of friction force and roughness data according to the progress of ice abrasion.

• Journal of Korean society of Dental Hygiene
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• v.21 no.2
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• pp.99-107
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• 2021

Objectives: To compare and evaluate the degree of abrasion of the denture base resin according to the type of denture cleansers. Methods: Denture base resin specimens were prepared and dried. The resin specimens were installed in the automatic brushing machine so that the toothbrush weighed 200 g. The brushing was performed 1,000 times each, a total of 10,000 times using (1) distilled water (DW), (2) non-abrasive cleanser (NAC), and (3) toothpaste (TP), respectively. Thirty specimens were allocated for each group. The thickness of abrasion by brushing was calculated by converting the weight of the specimen. Results: In all DW, NAC, and TP groups, significant differences were found in the average amount of abrasion of the resin specimen due to 1,000 to 10,000 brushings (p<0.001). The average abrasion amount of the resin specimen due to brushing 10,000 times was 2.31±1.20 ㎛ in DW group, 2.52±0.25 ㎛ in NAC group, 6.50±0.60 ㎛ in TP group, and the amount of abrasion in the TP group was statistically significant compared to other groups (p<0.001). Conclusions: The use of TP is not recommended as a method for maintaining the longevity of dentures and for oral health, and NAC was considered to be possible to be used as a denture cleanser because it had a similar amount of abrasion of that of DW.