• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.08a
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• pp.272-278
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• 1999

Tungsten Carbide(WC) Roll is widely used in finishing stands of wire rod mill. This report is about the manufacturing method of WC roll with excellent wear resistance. To enhance wear resistance, WC content has been increased to the maximum extent while binder content such as Co, Ni, Cr has been minimized. Part of WC is replaced with TiC having more wear resistant than WC. WTiC powder has been used to prevent weight unbalance resulting from the difference of specific weight when adding TiC. The roll manufactured by this method, is having more wear resistance than the existing rolls when applying to the final stand of the finishing mill. This report shows that WC is the critical factor of wear resistance in WC rolls and an approprite amount of TiC effects wear resistance and when adding TiC, using WTiC powder is better.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.2
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• pp.143-150
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• 2007

Ring and cylinder bore wear may not be a problem in most current automotive engines. However, a small change in ring face and cylinder bore diameter can significantly affect the lubrication characteristics and ring axial motion. This in turn can cause to change inter-ring pressure, blow-by and oil consumption in an engine. Therefore, by predicting the wear of piston ring face and cylinder bore altogether, the changed ring end gap and the changed volume of gas reservoir can be calculated. Then the excessive oil consumption can be predicted. Here, the oil amount through top ring gap into combustion chamber is estimated as engine oil consumption. Furthermore, the wear theories of ring and cylinder bore are included. The changed oil consumption caused by the new end gap and the new volume of oil reservoir around second land, can be calculated at some engine running interval. Meanwhile, the wear amount and oil consumption occurred during engine durability cycle are compared with the calculated values. The wear data of rings and cylinder bore are obtained from three engines after engine durability test. The calculated wear data of each part are turn out to be around the band of averaged test values or a little below. It is shown that the important factor regarding oil consumption increasement is the wear of ring face.

• Fashion & Textile Research Journal
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• v.18 no.1
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• pp.27-37
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• 2016

This study examined consumer perceptions towards outdoor wear differentiation and product attributes for outdoor wear differentiation to develop an outdoor wear differentiation strategy. It also investigated how consumer's evaluated product attributes according to consumer's demographic characteristics. Data were acquired from a survey of 454 adult respondents aged over 20 that was analyzed with descriptives, frequency, t-test, one-way ANOVA, factor analysis, and reliability. The results were as follows. First, it showed that consumers did not have a positive or a negative perception toward outdoor wear differentiation, and they thought outdoor wear should be differentiated. Those married and older tended to think that outdoor wear should be differentiated more than that for those single and younger. Consumer evaluations were significantly different on the necessity of outdoor wear differentiation according to age and total income. Second, consumers assessed that color, pattern and textiles had similar characteristics among outdoor wear brands; in addition, brand recognition and brand image had very different characteristics. Third, product attributes for outdoor wear differentiation were service and store, product quality, brand and popularity, and product designs with mean values of product quality, product design, service and store, and brand and popularity, respectively. Fourth, consumers were significantly different in the importance assessment of product attributes for differentiation according to gender, marital status and age.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.5 s.248
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• pp.496-504
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• 2006

Wear of engine valves and seat inserts is a major factor affecting engine performance. In order to improve quality and life of valve assemblies, wear mechanism and 3-D surface topography should be analyzed according to operating conditions of the engine. After developing an engine simulator that generates valve speed up to 90Hz and temperature up to $900^{\circ}C$ as well as controls test load, wear experiments have been conducted for two different engine speeds as 10Hz and 25Hz. In order to observe the wear characteristics and monitor surface conditions of the valve assemblies, a cost-effective 3-D wear analysis system based on the shape from focus(SFF) and machine vision has been fabricated in this paper. 3-D surface topography of the valve assemblies has been analyzed to understand the wear behavior according to operating conditions of the engine. Consequently, wear volume of the valve assemblies is quantized by using the developed 3-D wear analysis system.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.6
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• pp.1441-1455
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• 1993

Under unlubricated condition, the friction and wear tests of silicon nitride and zirconia manufactured by HIP were carried out at room temperature. The wear resistance of silicon nitride was superior to that of zirconia under low load, whereas the wear resistance of zirconia was superior to that of silicon nitride under high load. Wear model of ceramic was suggested by the microscopic SEM observation of worn surfaces and debris. Theoretical analysis and discussions based on linear fracture mechanics were made out about this ceramic wear model. From the theoretical analysis, a new nondimensional parameter, Scf, was introduced to estimate wear rate of ceramics. This new nondimentional parameter consists of contact pressure, surface defect of contact material, frictional coefficient and fracture toughness.

• Restorative Dentistry and Endodontics
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• v.46 no.2
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• pp.18.1-18.13
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• 2021

Composite resins are the most commonly used dental restorative materials after minimally invasive dental procedures, and they offer an aesthetically pleasing appearance. An ideal composite restorative material should have wear properties similar to those of tooth tissues. Wear refers to the damaging, gradual loss or deformation of a material at solid surfaces. Depending on the mechanism of action, wear can be categorized as abrasive, adhesive, fatigue, or corrosive. Currently used composite resins cover a wide range of materials with diverse properties, offering dental clinicians multiple choices for anterior and posterior teeth. In order to improve the mechanical properties and the resistance to wear of composite materials, many types of monomers, silane coupling agents, and reinforcing fillers have been developed. Since resistance to wear is an important factor in determining the clinical success of composite resins, the purpose of this literature review was to define what constitutes wear. The discussion focuses on factors that contribute to the extent of wear as well as to the prevention of wear. Finally, the behavior of various types of existing composite materials such as nanohybrid, flowable, and computer-assisted design/computer-assisted manufacturing materials, was investigated, along with the factors that may cause or contribute to their wear.

• Journal of the Korean Society of Clothing and Textiles
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• v.42 no.6
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• pp.1025-1038
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• 2018

This study identifies the socio-psychological factors on athleisure wear purchase behavior and focuses on the effects of participation motives in sports leisure activity. This research compares athleisure wear purchase behavior among the three groups segmented by participation motives for sports and leisure activity. An online survey on male and female consumers between the ages of 20 and 50 provided 319 responses that were analyzed using SPSS 20.0. The factor analysis and reliability analysis, cluster analysis, variance analysis, Duncan test, and Chi square test were conducted. The results were: 1) From a result of the factor analysis on consumers' sports leisure participation motives clearly showed factorial structures including social interaction, physical health, and pleasant feeling. 2) Cluster analysis indicated three groups of participation motives in sports and leisure activity such as passive motivating type, social interaction type, and wellness type. 3) Consumer groups showed significant differences in purchase reasons, preferred brands, product items, and pursued performance attributes for purchasing athleisure wear products.

• Fashion & Textile Research Journal
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• v.17 no.6
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• pp.965-977
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• 2015

This study aims to investigate determinants that included personal values, pro-environmental beliefs, and proenvironmental norms for enhancing consumers' purchase intention of eco-friendly outdoor wear exploring Stern(2000)’s the value-belief-norm theory. A survey was conducted with females and males between the ages of 20 and 60 who have experienced buying outdoor wear products. A total of 300 responses were analyzed by descriptive analysis, factor analysis, a reliability test, an independent samples t-test, and regression analysis. The results of this study were as follows: 1) The results of exploratory factor analysis and reliability test on the personal value clearly showed factorial structures including the social power, ecologic value, openness, equality, and altruistic value. 2) There are significant differences in personal value sub-dimensions, pro-environmental beliefs, pro-environmental norm, and purchase intention of eco-friendly outdoor wear products according to respondents' gender and age. 3) Personal values, but not social power, affect pro-environmental beliefs; in turn, pro-environmental beliefs affect pro-environmental norms, which then affects purchase intentions of eco-friendly outdoor wear. The findings support the conclusion that there is significant causality among personal value such as ecologic, openness, equality, and altruistic, pro-environmental belief, and pro-environmental norm. This study suggests pragmatic implications to understand outdoor wear consumers' socio-psychological and demographic factors and to augment purchase intentions of eco-friendly outdoor wear products.

• Tribology and Lubricants
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• v.34 no.4
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• pp.146-159
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• 2018

This paper presents a wear analysis procedure for calculating the wear of journal bearings of a four-strokes and four-cylinder engine operating at a constant angular crank shaft speed during firing conditions. To decide whether the lubrication state of a journal bearing is in the possible region of wear scar, we utilize the concept of the centerline average surface roughness to define the most oil film thickness scarring wear (MOFTSW) on two rough surfaces. The wear volume is calculated from the wear depth and wear angle, determined by the magnitude of each film thickness on a set of oil films with thicknesses lower than the MOFTSW at every crank angle. To calculate the wear volume at one contact, the wear range ratio during one cycle is used. The total wear volume is then determined by accumulating the wear volume at every contact. The fractional film defect coefficient, asperity load sharing factor, and modified specific wear rate for the application of the mixed-elasto-hydrodynamic lubrication regime are used. The results of this study show that wear occurs only at the connecting-rod big-end bearing. Thus, simulation results of only the big-end bearing are illustrated and analyzed. It is shown that the wear volume of each wear scar group occurs consecutively as the crank angle changes, resulting in the total accumulated wear volume.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.6
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• pp.14-20
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• 2003

The minimization of valve and seat insert wear is a critical factor in the pursuit of engine performance improvement. In order to achieve this goal, we have developed a new simulator, which can generate and control high temperatures up to $900^{\circ}C$ and various speeds up to 80Hz during motion, just like an actual engine. The wear simulator is considered to be a valid simulation of the engine valve and seat insert wear process with various speeds during engine activity. The objective of this work focuses on the different degrees of wear from two different test speeds (10Hz & 25Hz). For this study, the temperature of the outer surface of the seat insert was controlled at $350^{\circ}C$, the cycle number was 2.1$\times$106, and the test load was 1960N. The wear depth and surface roughness were measured before and after the testing using a confocal laser scanner. It was found that a higher speed (25Hz) causes more wear than a lower speed (10Hz) under identical test conditions (temperature, cycle number and test load). In the wear mechanism adhesive wear, shear strain and abrasive wear could be observed.