• Advances in concrete construction
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• v.8 no.1
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• pp.47-54
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• 2019

Portland cement pervious concrete has been expected to have good water permeability, mechanical properties and abrasion resistance at the same time when Portland cement pervious concrete is applied to the actual vehicle pavement. In this study, the coarse aggregate and cement were replaced by the fine aggregate and the silica fume to improve actual road performance Portland cement pervious concrete. The Mechanical properties, the water permeability and the abrasion resistance of Portland cement pervious concrete were investigated. The results show that the compressive strength, the flexural strength and the abrasion resistance are increased when the fine aggregate and the silica fume are added to Portland cement pervious concrete separately. However, the porosity and the water permeability are decreased simultaneously. With assistance of silica fume and fine aggregate simultaneously, Portland cement pervious concrete could achieve a higher strength. The compressive strength, the flexural strength and the abrasion resistance of Portland cement pervious concrete mixed with 5% fine aggregates and 8% silica fume are increased by 93.1%, 65% and 65.2%, respectively. The porosity and the water permeability are decreased by 22.4% and 85% when Portland cement pervious concrete is mixed with 5% fine aggregate and 8% silica fume. Therefore, the replacement ratio of the fine aggregates and the silica fume should be considered comprehensively and determined on the premise of ensuring the water permeability coefficient.

• Journal of Forest and Environmental Science
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• v.26 no.2
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• pp.131-136
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• 2010

In an effort to evaluate the qualities of the unused woods designed for art materials, Yellow pine, Pitch pine, Suwon poplar, Platanus and Cherry grown in Korea has been investigated in the study. Physical and mechanical properties such as density, hardness, roughness, and abrasion of the woods were examined. Among the five species, Cherry wood showed the highest density in green, air-dried and oven-dried conditions. Hardness of Cherry wood was higher than those of Suwon poplar and Platanus. In softwoods, Pitch pine showed greater hardness than Yellow pine. Yellow pine and Platanus had the highest values of wood surface roughness. Abrasion value of cross, radial and tangential sections was the highest in Yellow pine and Suwon poplar. It has been concluded from the experiment that physical and mechanical properties such as density, hardness, roughness, and abrasion of the woods can be used as an indicator of the suitability for woodcraft material.

• Journal of the Korean Wood Science and Technology
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• v.43 no.6
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• pp.792-797
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• 2015

In this study, three softwood species were treated with water-soluble melamine resin by different concentration and treatment time under vacuum pressure for improving mechanical property, abrasion resistance, and incombustibility. After the treatment, a compreg was manufactured and then evaluated on physical properties. Additionally, incombustibility of compreg was determined by comparing with a wood that was treated by spraying a water-soluble fire retardant on surface. As concentration of resin increased, bending strength and Brinell hardness increased as well as abrasion resistance, but there was no correlation on treatment and mechanical properties by treatment time. The wood impregnated by water-soluble melamine resin under vacuum pressure showed better incombustibility than that of a water-soluble fire retardant sprayed wood. Therefore, this treatment could be used for improving incombustibility of wood.

• Design & Manufacturing
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• v.7 no.1
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• pp.40-44
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• 2013

My company develops, manufactures injection mold and produces thin-walled cosmetics and food containers. Without high quality and low production cost, it is hard to compete in the market. To be competitive, a company has to utilize mold with as many cavities as possible to lower manufacturing cost. Eject plate abrasion and deformation cut down mold lifespan, troubles during injection lower productivity and foreign substances in molds cause abrasion. This study focuses on how to improve mold life and productivity, and to slow down mold abrasion.

• Journal of the Korea Furniture Society
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• v.26 no.4
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• pp.392-397
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• 2015

This study was carried out to analyze the effects on mechanical properties of deteriorated wood member by outdoor condition. The surface color, mechanical properties and structural stability of traditional wooden structures, exposed in water and UV, could be changeable. For the purpose, accelerated weathering test based on outdoor condition was carried out. The weathering time levels were composed 0, 500, 1000, 1,500 and 2,000 hours and mechanical properties were evaluated on each specimen according to weathering time level. Bending properties were decreased on weathering but recovered after 1,000 hours. Fatigue and impact strength were decreased to 1,000 hours and did not changed since then. Abrasion resistance was minimized in 1,000 hours. This results could be utilized for effectively stability management of traditional wooden structures and members.

• Tribology and Lubricants
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• v.39 no.6
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• pp.250-255
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• 2023

This study applies various surface patterns to minimize material loss in construction equipment that is subject to severe wear due to sand, such as the wear-resistant steel plates of dump trucks or the teeth of excavators. The relationship between surface morphology and wear behavior is investigated using PLA+ polymer to observe the effect of the surface pattern. Five types of samples - smooth, concave, convex, wavy concave, and wavy convex designs - are created using a 3D printer. A wear experiment is conducted for a duration of 3 h using 6.5 kg of abrasive particles. The mass loss of the samples after the experiment is measured to assess the extent of wear. Additionally, the surface morphology of the samples before and after the experiment is analyzed using SEM and confocal microscopy. The study results reveal that the smooth design exhibits the highest wear loss, whereas the concave and wavy concave designs show relatively lower wear loss. The convex and wavy convex designs exhibit varying contact areas with the abrasive particles depending on the surface pattern, resulting in different levels of wear. Furthermore, a comparison between the experimental results and DEM simulations confirms the observed wear trends. This study reveals the relationship between wear damage according to surface pattern shape and is expected to be of substantial help in the analysis of wear and tear on agricultural and heavy equipment.

• The Journal of Advanced Prosthodontics
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• v.5 no.4
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• pp.382-387
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• 2013

PURPOSE. Although several surface treatments have been recently investigated both under in vitro and in vivo conditions, controversy still exists regarding the selection of the most appropriate zirconia surface pre-treatment. The purpose of this study was to evaluate the effect of alumina (Al) and aluminium nitride (AlN) coating on the shear bond strength of adhesive resin cement to zirconia core. MATERIALS AND METHODS. Fifty zirconia core discs were divided into 5 groups; air particle abrasion with 50 ${\mu}m$ aluminum oxide particles ($Al_2O_3$), polishing + Al coating, polishing + AlN coating, air particle abrasion with 50 ${\mu}m$ $Al_2O_3$ + Al coating and air particle abrasion with 50 ${\mu}m$ $Al_2O_3$ + AlN coating. Composite resin discs were cemented to each of specimens. Shear bond strength (MPa) was measured using a universal testing machine. The effects of the surface preparations on each specimen were examined with scanning electron microscope (SEM). Data were statistically analyzed by one-way ANOVA (${\alpha}$=.05). RESULTS. The highest bond strengths were obtained by air abrasion with 50 ${\mu}m$ $Al_2O_3$, the lowest bond strengths were obtained in polishing + Al coating group (P<.05). CONCLUSION. Al and AlN coatings using the reactive magnetron sputtering technique were found to be ineffective to increase the bond strength of adhesive resin cement to zirconia core.

• Journal of Dental Rehabilitation and Applied Science
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• v.26 no.3
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• pp.339-347
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• 2010

Enhancement of bond strength between new and old composite usually requires increasing the surface roughness to promote mechanical interlocking. This study evaluated the effect of different surface treatments on repair bond strength of resin composite after aging condition. Air abrasion with Al2O3, chairside silicacoating, and silanization provided higher resin-resin bond strength values compared to control group and HF group. Air abrasion is necessary to repair a resin restoration and additional application of silane seems to have good effects on bond strength.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.148-153
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• 2007

The effect of silicon carbide (SiC) and graphite fillers incorporation on the abrasive wear behaviour of glass-vinyl ester (G-V) composites have been investigated. The three-body abrasive wear behaviour was assessed by rubber wheel abrasion tests (RWAT). The worn surfaces were examined using scanning electron microscopy (SEM). The addition of SiC and graphite fillers in G-V composite improves the abrasion resistance under different loads/abrading distances. The SEM studies indicate the reasons for failure of composites and influencing parameters.

• Journal of Biomedical Engineering Research
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• v.21 no.3 s.61
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• pp.279-283
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• 2000

After ACL reconstruction. abrasion or wear of graft appeared frequently because of contact stresses between femoral tunnel and ACL. To minimize these problems. optimal shape of femoral tunnel is necessary. In this study. we evaluate friction force by degree of wear due to abrasion of soft tissue and develop 3-dimensional FEM model using ANSYS 5.5.1 version to analyze stress growths between femoral tunnel and ACL, We conclude that femoral tunnel angle must be slacked parallel to tunnel direction to minimize contact stress.