• Elastomers and Composites
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• v.50 no.2
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• pp.110-118
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• 2015

In this study, diethylaminoethyl methacrylate-styrene-butadiene terpolymer (DEAEMA-SBR), in which diethylaminoethyl methacrylate (DEAEMA) was introduced to the SBR molecule as a third monomer, was synthesized by cold emulsion polymerization. It is expected that amine group introduced to a rubber molecule would improve dispersion of silica by the formation of hydrogen bond (or ionic coupling) between the amine group and silanol groups of silica surface. The chemical structure of DEAEMA-SBR was analyzed using proton nuclear magnetic resonance spectroscopy (H-NMR), Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC) and differential scanning calorimetry (DSC). Then, various properties of DEAEMA-SBR/silica composite such as crosslink density, bound rubber content, abrasion resistance, and mechanical properties were evaluated. As a result, bound rubber content and crosslink density of DEAEMA-SBR/silica compound were higher than those of the SBR 1721 composite. Abrasion resistance and moduli at 300% elongation of the DEAEMA-SBR/silica composite were better than those of SBR 1721 composite due to the high bound rubber content and crosslink density. These results are attributed to high affinity between DEAEMA-SBR and silica. The proposed study suggests that DEAEMA-SBR can help to improve mechanical properties and abrasion resistance of the tire tread part.

• The Journal of Engineering Geology
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• v.34 no.1
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• pp.67-105
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• 2024

This study compares the quartzites of four quartzite units: The Fagfog Quartzite, Dunga Quartzite (member of the Robang Formation), Pandrang Quartzite (member of the Kalitar Formation) and the Chisapani Quartzite. The analysis shows variations in flakiness and elongation, as the Fagfog Quartzite displays low flakiness whereas the Pandrang and the Chisapani have moderate and the Dunga Quartzite has shown variations. The density values of the four quartzite units remain consistent, indicating uniform physical properties and porosity levels. However, bulk density values differ among the quartzites, suggesting variations in particle arrangement, porosity, and density. Regarding strength measures, the Pandrang and the Chisapani Quartzite have higher strength characteristics as compared to the Fagfog and the Dunga Quartzites. The Pandrang Quartzite has the highest average point load strength index, classifying it as "Extremely Strong". The resistance to impact and crushing forces varies among the quartzites, with lower Aggregate Impact Value (AIV) and Aggregate Crushing Value (ACV) indicating higher strength and durability. Durability tests show that the Fagfog Quartzite has high durability against slaking, with a slight decrease observed after the fifth cycle. The Dunga Quartzite shows varying degrees of weathering, while the Pandrang and the Chisapani Quartzite have minimal weight changes, indicating strong resistance to weathering. Magnesium sulfate soundness tests indicate high durability and resistance to degradation for all four units. The Los Angeles abrasion value (LAAV) tests indicate favorable resistance to abrasion for the majority of the Fagfog, Dunga, and the Pandrang Quartzites samples, while Chisapani Quartzite shows more variability in LAAV values. The Pandrang Quartzite shows a higher proportion of elongated particles but lower flakiness index values as compared to Fagfog and Dunga Quartzites while Chisapani Quartzite stands out with a significantly higher presence of flaky particles and lower elongation index values. Mechanically, the Fagfog and Dunga Quartzite show higher strength and better resistance to abrasion and freeze and thaw. The Pandrang Quartzite shows moderate resistance to crushing and sudden effect, while the Chisapani Quartzite has variable resistance to effect. This comparative study emphasizes the diversity and complexity of quartzite rock types, showing the need for comprehensive characterization and assessment to determine their suitability for specific applications.

• Journal of the Korea Institute of Building Construction
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• v.13 no.5
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• pp.449-456
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• 2013

This study was carried out to assess the suitability in terms of the standards of material quality of basalt aggregates from JEJU Island as a source for concrete aggregate. Quality assessments on the basalt aggregates were performed to assess the soundness of coarse aggregates using sodium sulfate solution, aggregate crushing test, and Los Angeles abrasion test. In addition, XRD, XRF, porosity, and compressive and tensile strength tests were performed to analyze the chemical components and the mechanical properties. In general, the mechanical properties of basalt aggregates from some areas did not meet the Korea Standards (KS), but the levels of compressive and tensile strength were higher than those of granite, andesite, and sandstone of other regions.

• Transactions of the Korean hydrogen and new energy society
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• v.25 no.2
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• pp.145-150
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• 2014

This study investigates the preparation of anti-reflective (AR) coating film to improve the efficiency of solar cell. The AR coating film was successfully obtained by dip-coating with AR coatings prepared by sol-gel method. Fluoroalkylsilane was additionally introduced into the coatings to give the self-cleaning effect of AR coating film. We performed the abrasion test, pencil scratch hardness test and cross-cut test to identify the mechanical strength of AR coating film. As the results, the transmittance of AR coating films with 9.07, 18.13 and 27.20 of IPA/MTMS molar ratios were 93.1, 93.6 and 95.3%, respectively. The water contact angle and transmittance of AR coating film increased by the introduction of hydrophobicity. The prepared AR coating film shows the high level of abrasion, hardness and adhesion. The IPA/MTMS molar ratio of 27.20 and the withdrawing speed range of 0.20 ~ 0.28cm/sec are the optimal coating condition in terms of the transmittance and mechanical strength of AR coating film.

• Korean Journal of Materials Research
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• v.17 no.11
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• pp.601-605
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• 2007

The tribological properties of acrylonitrile-butadiene rubber (NBR) filled with two kinds of carbon black filler were examined. Different types of Semi-Reinforcing Furnace (SRF), and High Abrasion Furnace (HAF) blacks were used as filler material to test the influence of carbon black particle size on the friction and wear of NBR. Results from tribological tests using a ball on disk method showed that the smaller HAF particles were more effective for reducing the wear of NBR during frictional sliding. The hardness, elastic modulus at 100% elongation, and elongation at break were measured to examine the correlation between the effects of carbon black on the mechanical and tribological properties of the NBR specimens. The wear tracks of the NBR specimens were observed with scanning electron microscopy (SEM). The wear tracks for NBR with different ratios of SRF and HAF showed clearly different abrasion patterns. Mechanisms for the friction and wear behavior of NBR with different sizes of carbon black filler were proposed using evidence from wear track observation, as well as the mechanical and tribological test results.

• Journal of the Korean Society of Clothing and Textiles
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• v.33 no.1
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• pp.149-159
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• 2009

The purposes of this study are to evaluate physical performance of metallic Jacquard fabrics, and to contribute to the research and development of the women's suit made of the metallic Jacquard fabrics. First, eight fabrics were woven with two kinds of warp yarns(nylon and rayon) and weft yarn blended with various contents(0, 7, 14, 21%) of metallic yarn. Second, the mechanical properties were measured by using the KES-FB system, and physical properties such as tensile strength, tearing strength, abrasion resistance, drape, pilling, snagging, degree of crease resistance, flexural stiffness, specular gloss, folding endurance and electrostatic propensity were measured. The results were as follows. As the metal fiber content increased, bending, shear, thickness and weight increased, which imply low recovery of wrinkles. It means that metallic Jacquard fabrics enable to use as a memory fabric. 7% metallic Jacquard fabric showed a low value at total hand value, but there was little change. As the metal fiber content increased, tensile strength, tearing strength, drape coefficient, specular gloss and flexural stiffness increased, however the degree of crease resistance, electrostatic propensity and folding endurance decreased. The metallic Jacquard fabrics were excellent in snagging, abrasion resistance and pilling.

• Plant Journal
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• v.6 no.2
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• pp.62-69
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• 2010

The stability of coal pulverizer in the 800 MW coal-fired plants is vital to maintain their performance. Thus, this study analyzed the uneven abrasion of the deflector and coal spillage due to the air velocity maldistribution in the vane wheel of a bowl-type pulverizer as it is a possible cause for problems of facility using pulverized coal. In addition, air flow in the underbowl of a bowl-type pulverizer was studied to check air velocity maldistribution in the vane wheel using numerical method. In an attempt to correct the maldistribution of air velocity, air flow of the modified duct vane was studied as enlarging the length of the duct vanes installed at the air inlet duct of the pulverizer and increasing the angle of inclination. It was found that modified duct vane make the velocity distribution at the vane wheel uniform. formed by the duct vanes installed at the air inlet duct of the pulverizer and swirling flow is the major factor in making the velocity distribution of vane wheel exit uniform. This can prevent the uneven abrasion of the deflector, which is one of the components inside the pulverizer and coal spillage.

• Journal of the Korean Society of Safety
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• v.25 no.6
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• pp.65-69
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• 2010

This paper presented an experimental study of slip resistance characteristics of shoes and floor surface contact with special focus on the effect of surface roughness, outsole material and mechanical abrasion. The factors that affected the results of slip resistances were investigated for four kinds of rubbers and five kinds of floor samples using the VIT(English XL) tribometer. The slip resistance was observed to increase gradually with increasing roughness for five kinds of floor roughness. In the higher surface roughness (larger than $11.5{\mu}m$), the slip resistance increased more rapidly and exceeded safety criteria at $22.60{\mu}m$. The slip resistance was observed to decrease with increasing hardness of outsole, except for butylenes rubber, which seemed to show the material property. The slip resistance decreased with number of trials. In the first several times(5 or 6 trial), the slip resistance decreased more rapidly, whereafter it approached gradually constant value. The slip resistance of surfaces has generally been shown to increase with floor surface roughness and to decrease with hardness of outsole and number of trials under the wet condition.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.806-810
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• 2008

This paper introduces the automatic fine Bituminous Coal injection lance position control method using flame image process. The fine Coal injection lance is used to supply additional heat into the furnace in Mill plant. It injects fine coal into high pressured air flow and produces very heated and high pressured flame. For the such high temperature and pressure, the fine coal injection lance effects not only efficiency of burner but also furnace abrasion. To keep efficient combustion status and to avoid the abrasion, in this paper, the flame is monitored by computer image process. This paper proposes the flame image process method and lance position control according to calculated result for flame image process.

• Journal of the Korean Society of Safety
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• v.23 no.6
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• pp.7-13
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• 2008

It is important to prevent roll failure in hot rolling process for reducing maintenance cost and production loss. The relationship between rolling pass schedule and the work roll wear profile will be presented. The roll wear pattern is related with roll catastrophic failure. The irregular and deep roll wear pattern should be removed by On-line Roll Grinder(ORG) for roll failure prevention. In this study, a computer roll wear prediction model under real process working condition is developed and evaluated with hot rolling pass schedule. The method of building wear calculation functions for center portion abrasion and marginal abrasion respectively was used to develop a work roll wear prediction mathematical model. The three type rolling schedule are evaluated by wear prediction model. The optimum roll grinding methods is suggested for schedule tree rolling technique.