• Fashion & Textile Research Journal
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• v.18 no.4
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• pp.489-497
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• 2016

The purpose of this study is to most appropriately develop maternity wear according to the preferences of specific age groups of pregnant women. The specific age groups were women in their twenties, early thirties, and late thirties. This survey was conducted in the metropolitan area around Seoul, South Korea through a questionnaire given to 150 pregnant women. The study found that pregnant women purchased significantly cheaper clothes after their pregnancy than before. The participants responded that they mostly bought clothes using the Internet, but they also reported many instances of returning the clothes due to fit and sizing. It was shown that women in their twenties tended to consider the price, design, and activity more than women in their thirties when purchasing maternity wear. The study showed that pregnant women tended to wear maternity wear from early in the pregnancy-preferring leggings, one-piece dresses, pants, shirts, briefs, and bras with the girdle on the outside. More women in their late thirties purchased maternity support belts than younger age groups. In any case, in purchasing maternity wear, clothing features that the respondents focused on were comfort, functionality, fit, the covering of their body changes, and fashion. Still, many respondents 35 years and older reported more interest in safety rather than fashion in comparison to the responses of respondents under the age of 35.

• Tribology and Lubricants
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• v.20 no.2
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• pp.91-96
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• 2004

Wear behavior of self-mated stainless steels in NaCl solution has been investigated. The experiment was done in the corrosive liquid of which NaCl concentration of $0\~3\%$ and temperature of $15\~90^{\circ}C$. Two kinds of wear type were observed: one is 'severe wear' type which shows gradually increasing wear volume with increasing sliding distances, the other is 'mild wear' type which shows change of wear rate from high value to low at transition distance. The specific wear rate in severe wear type was not sensitive to the liquid temperature and concentration of NaCl but stable at value of $1\times10^{-3}\;mm^3$ approximately.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.119-122
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• 2005

A study on motor current signature analysis has been executed for monitoring the fault of journal bearing due to wear. The air gap eccentricity of motor produces specific frequencies in motor current, the supplied current frequency plus and minus rotational rotor frequency. The air gap eccentricity is simulated by the clearance of Journal bearing. The amplitudes of the specific frequencies increase with the increasing clearances. The amplitudes of the specific frequencies continue to increase over the wear limit that is used in the manufacturer of the test motor. Though clear relations between the amplitudes of the specific frequencies and the clearances are not obtained in this paper, the specific frequencies can be used as an indicator of a journal bearing fault. Further study is necessary to make out the quantitative relations between the specific frequencies and the clearances.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.10
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• pp.873-878
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• 2016

SCM415 steel for the control valve undergoes wear because of continuous movement between the valve and valve case. The wear of the valve interrupts the performance of the valve, and decreases the service life. In this study, wear characteristics of the as-received and carburized SCM415 steels are evaluated. The wear tests are conducted for various temperatures and loads using a reciprocating wear tester. From these results, wear loss, specific wear rate, and coefficient of friction are analyzed. The wear mechanism was analyzed by SEM. The interaction effects between loads and temperatures on wear loss are determined for analysis of variance using MINITAB.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.6
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• pp.1404-1411
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• 1993

This study was undertaken to investigate the corrosive wear charateristics upon various transformation condition of austempered low-alloy ductile cast iron in corrosive environments against mating specimen made of the hardened SM45C. The corrosive wear test was carried out by rubbing the annular surface of two test pieces in distilled water and aqueous solution at constant sliding speed of 0.5m/s. In severe wear region, the corrosive wear rate Wc increased hastily with NaCl concentration owing to intermetallic adhesion but Wc went down slowly in mild wear region due to lubricating effect of the corrosion product. The critical sliding distance decreased with increasing NaCl concentration due to increased generation rate of the corrosion product and the specific corrosive wear rate has maximum in 1% NaCl aqueous solution at mild wear region. With the variation of matrix, the corrosive wear resistance of the fine acicular bainite was higher than that of coarse upper bainite because of reducing the local cell reaction by carbides. A growth in volume fraction of retained austenite in matrix increased the Wc due to soften surface, but has a declining tendency of Wc in mild wear region.

• Tribology and Lubricants
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• v.19 no.4
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• pp.223-229
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• 2003

The sliding wear characteristics of the crane sheave were investigated using a pin-on-disk rig tester. The experiment was conducted using a high carbon steel wire that was upper material, also carbon steel castings that was disk material. There are various operating conditions in this work. At the room temperature, we carried out the wear test under a grease lubrication and dry condition. The results of wear test showed that an annealed-casted have lower, also the wear curves are linearly increased with increasing of sliding distance. For the specific wear rate of annealed-casted, the wear resistance was increased with decreasing diameter of wire. The wear of a wire and a disk have a different mechanism, the one is the abrasive wear due to fatigue wear under lubrication, another is the adhesion wear under dry condition.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.04a
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• pp.46-49
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• 2003

Aluminum based metal matrix composites(MMCs) are well known for their high specific strength, stiffness and hardness. They are gaining further importance because of their high wear resistance. In this study, Al/Saffil-20%, Al/Saffil-5%/Al2O3(particle type)-15% and Al/Saffil-5%/SiC(particle type)-15% hybird MMCs' wear behavior were characterized by the pin-on-disk test under various normal load The superior wear resistance was exhibited at Al/Saffil-5%/SiC(particle type)-15% MMCs. And this MMCs' predominant wear mechanism is subsurface cracking in the low load wear regime. Others(Al/Saffil-20%, Al/Saffil-5%/Al2O3(particle type)-15%) showed the similar wear resistance with each other at the same test condition. In the low load & room temperature condition, the wear resistance was improved due to the high hardness of the ceramic reinforcements. As the test load increased, the wear properties were governed by the wear properties of matrix.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.11
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• pp.1873-1880
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• 2003

The sliding wear characteristics of the crane sheave were investigated using a pin on disk rig tester. The experiment was conducted using a high carbon steel wire that was upper material, also carbon steel castings that was disk material. There are various operating conditions in this work. At the room temperature, we carried out the wear test under a grease lubrication and dry condition. The results of wear test showed that an annealed-casted have lower, also the wear curves are linearly increased with increasing of sliding distance. For the specific wear rate of annealed-casted, the wear resistance was increased with decreasing diameter of wire. The wear of a wire and a disk have a different mechanism, the one is the abrasive wear due to fatigue wear under lubrication, another is the adhesion wear under dry condition.

• Journal of Power System Engineering
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• v.9 no.2
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• pp.57-64
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• 2005

This paper is the study on dry sliding wear behavior of carbon fiber reinforced epoxy matrix composites against lay-up orientation. Tests were investigated on the effect of the lay-up orientation, fiber sliding direction, load and sliding velocity when circumstance keep continuously at $21^{\circ}C$, 60%RH. Pin-on-disk dry sliding wear tests for each experimental condition were carried out with a carbon fiber reinforced plastic pin on stainless steel disk in order to search the friction and wear characteristics. The wear rates and friction coefficients against the stainless steel counterpart were experimentally determined and the wear mechanisms were microscopically observed. The effect on friction and wear behavior are observed differently, according to various conditions. When sliding took place against counterpart, the highest wear resistance and the lowest friction coefficient were observed in the $[0]_{24s}$ lay-up orientation at anti-parallel direction.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.2 s.173
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• pp.464-471
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• 2000

The fracture and wear behavior of dental composite resins containing prepolymerized particle fillers were investigated. Composite resins such as Metafil, Silux Plus, Heliomolar and Palfique Estelite were selected as specimens and contents of filler in specimens in order to evaluate the effect of prepolymerized particle fillers in fracture and wear characteristics. Ball on flat wear tester was used for the wear test at room temperature. The friction coefficient of Metafil was quite high relatively, and the wear resistances of Silux Plus and Palfique Estelite were better than those of Metafil and Heliomolar at the same experimental condition. It was found that the main wear mechanism was abrasive wear containing of plastic deformation of dental material.