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AN IN-VITRO WEAR STUDY OF INDIRECT COMPOSITE RESINS AGAINST HUMAN ENAMEL (법랑질에 의한 수종의 간접복합레진의 마모에 관한 연구)

  • Yi, Hyun-Jeong;Jeon, Young-Chan;Jeong, Chang-Mo;Jeong, Hee-Chan
    • The Journal of Korean Academy of Prosthodontics
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    • v.45 no.5
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    • pp.611-620
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    • 2007
  • Statement of problem: Second-generation indirect composite resins have been improved flexural strength, compressive strength, hydrolytic degradation resistance, wear resistance compared to first-generation indirect composite resins, but there are still some problems as hydrolysis and low wear resistance. Some manufacturers claim that wear resistance of their materials has been improved, but little independent study has been published on wear properties of these materials and the properties specified in the advertising materials are largely derived from in-house or contracted testing. Purpose: This study was to evaluate the wear of indirect composite resins (SR Adore, Sinfony, Tescera ATL) and gold alloy against the human enamel. Material and method: Extracted human incisors and premolars were sectioned to $2{\times}2{\times}2mm$ cube and embedded in the clear resin and formed conical shaped antagonist to fit the jig of pin-on-disk tribometer. Total 20 antagonists were stored in distilled water. Five disk samples, 24mm in diameter and 1.5mm thick, were made for each of three groups of indirect composite resins and gold alloy group, and polished to #2,000 SiC paper on auto-polishing machine. Disk specimens were tested for wear against enamel antagonists. Wear test were conducted in distilled water using a pin-on-disk tribometer under condition (sliding speed 200rpm contact load 24N, sliding distance 160m). The wear of the enamel was determined by weighing the enamel antagonist before and after test, and the weight was converted to volumes by average density. The wear tracks were analyzed by scanning electron microscopy and surface profilometer to elucidate the wear mechanisms. Statistical analysis of the enamel wear volume, wear track depth and wear tract width of disk specimens were accomplished with one-way ANOVA and the means were compared for significant differences with Scheffe's test. Results: 1. The enamel wear was most in gold alloy, but there were no statistically significant differences among all the groups (P>.05). 2. In indirect composite resin groups, the group to make the most shallow depth of wear tract was Sinfony, followed by Tescera ATL, SR Adoro (P<.05). Gold alloy was shallower than Sinfony, but there was no statistically significant difference between Sinfony and gold alloy (P>.05). 3. The width of wear tract of SR Adore was larger than the other groups (P<.05), and there were no statistically significant differences among the other groups (P>.05). 4. SEM analysis revealed that Sinfony and gold alloy showed less wear scars after test, Tescera ATL showed more wear scars and SR Adore showed the most. Conclusion: Within the limits of this study, Sinfony and gold alloy showed the least wear rates and showed similar wear patterns.

The Design Development of Easy Casual Wear for Career Women (직장여성을 위한 이지 캐주얼 웨어 디자인 개발)

  • Byun, Mi-Yeon;Lee, In-Seong
    • Journal of the Korean Society of Clothing and Textiles
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    • v.30 no.8
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    • pp.1301-1311
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    • 2006
  • This study rearranged a concept of Friday wear considered as casual wear by searching social background through analysis of literature study and photo materials and classifying by characteristics of casual wear. It investigated growing changes of casual wear and the progress of changes casual brands through a market survey based on departments in Seoul. And then, it examined characteristics of a design and the critical point of easy casual selecting GIORDANO, TBJ and NII of three easy casual brands. Conclusions of the study are as follows: Firstly, present casual wear showed subdivision of casual wear as abundant grouping vocabularies appeared contrary to the past. Secondly, easy casual wear has continuously increased by results of investigating departments in Seoul on the progress of changing easy casual wear brand including the concept of Friday wear. Thirdly, if a main target sets the early 20s, women workers in their 20's and 30's are likely to be reluctant to wear it according to results of investigating designs and characteristics based on GIORDANO, TBJ and NII of existing three easy casual brands through the market survey. Also, it was verified that most of these brands have no a luxurious image because they adhere to middle-low price. Fourthly, it improved problems of easy casual through developing designs of easy casual wear. Easy casual wear supplementing weak these points of easy casual wear was evaluated as suitable clothes for workers to wear in on and off their own time in Friday.

The Effects of Mountain Climbing Motivation and Mountain Climbing Wear Benefits Sought on Clothing Usage Behavior (등산동기가 등산복 추구혜택 및 등산복 착용행동에 미치는 영향)

  • Ahn, Suh Young;Yoon, Seung Won;Lee, Mi Ah;Koh, Ae-Ran
    • Journal of the Korean Society of Clothing and Textiles
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    • v.37 no.4
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    • pp.565-576
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    • 2013
  • This study investigated 1) the effects of mountain climbing motivation on the desired mountain climbing wear benefits, and 2) the desired effects of mountain climbing wear benefits on clothing usage behavior. Data were collected via a questionnaire administered to 498 consumers who make at least one mountain climbing wear purchase for personal use. All items were evaluated on a 5-point Likert scale, and SPSS 20.0 and Amos 7.0 were used for data analysis. Confirmatory factor analysis for the research variables were performed and three factors of mountain climbing motivation (social interaction, health improvement, and mental rejuvenation), four factors of mountain climbing wear benefits sought (ostentation, ideal healthy figure, conformity, and functions), and two factors regarding clothing usage behavior (sportswear usage and daily wear usage) were identified. The results from the model test were as follows: 1) Mountain climbing motivation was found to vary depending on the mountain climbing wear benefits sought. Social interaction had a positive effect on all 4 factors of mountain climbing wear benefits sought. Health improvement was the only motivating factor for consumers who sought the benefit of functions; however, the functions benefit was not found to be a consideration for consumers who climbed for mental rejuvenation. 2) Mountain climbing wear usage was affected by mountain climbing wear benefits sought. The benefits for conformity and functions had a positive effect on sportswear usage and daily wear usage; however, the ideal healthy figure only affected daily wear usage. The twofold usage of mountain climbing wear reflects a cultural trend toward the usage of mountain climbing wear as daily wear; however, consumers show this twofold usage to conform successfully to mainstream society and not to pursue the ideal healthy figure.

A Study for the Improvement of the Nursery Active-wear Uniform -By Characters based on Children's Folklore Plays- (어린이집 활동복 개발 연구 -아동 민속놀이 캐릭터를 활용하여-)

  • Moon, Myeng Ok;Lee, Jin Suk;Um, Jung Ok
    • Fashion & Textile Research Journal
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    • v.15 no.3
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    • pp.347-357
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    • 2013
  • The nursery active-wear uniform designs of Internet shopping malls are simple and similar; however, the latest children's wear trends (mostly composed of training jumpers and pants) do not reflect these qualities. Children's folklore plays (widely used in child education) have an instructive value for the emotional and intellectual development of a child. Nursery active-wear uniform designs applied to children's folklore's plays could be positive for the emotional development and specialized cultural education of children. We designed three nursery active-wear uniforms with three different design concepts (casual, semi-formal and sporty) regardless of sex. The main color of the three nursery active-wear uniforms was yellow. We used three different chroma and values of yellow through three design concepts: Design I of a nursery active-wear uniform (a training suit style with a good activity), Design II of a nursery active-wear uniform (a semi suit style), and Design III of a nursery active-wear uniform (a sportswear style that reflected a sport wear trend). We expressed children's folklore plays in the pattern of a nursery active-wear uniform. The pattern was characterized as a pair of bears flying kites. This pattern was utilized in three nursery active-wear uniforms with the logo and name of the nursery. We modified the designs of active-wear nursery uniforms based on an evaluation of 33 special panels. We made three nursery active-wear uniforms for five-year olds.

Wear Characteristics of Cylinder-Liner Materials for Diesel Engine at Elevated Temperature (디젤엔진용 실린더 라이너 소재의 고온 마모특성)

  • Kim, Jin-Yeol;Kim, Jae-Hoon;Oh, Kwang-Keun;Lee, Seung-Hak;Chang, Joon-Yong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.39 no.11
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    • pp.1131-1136
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    • 2015
  • In a diesel engine, the wear of the cylinder liner occurs because of the continuous reciprocating motion of the piston ring. This wear reduces the performance of the diesel engine and shortens its service life. This study evaluated the wear characteristics of GT metal and a conventional metal used for cylinder liners using a ship's diesel engine. Wear tests were performed at temperatures of $25^{\circ}C$, $175^{\circ}C$, and $325^{\circ}C$, and under loads of 10 N, 30 N, and 50 N. The amount of wear, specific wear rate, and friction coefficient were evaluated for each condition. To analyze the wear mechanism, observations were made on an SEM. In the case of both metals, abrasive and adhesion wear occurred on the wear surfaces at room temperature, and corrosion wear was observed at high temperatures. The amount of wear and the specific wear rate of the GT metal were lower than those of the conventional metal at all temperatures, and hence it can be concluded that the wear characteristics of the GT metal are much better.

Wear Characteristics of Plastic Pinion Against Steel Gear for Different Pitch Line Velocities (운전속도에 따른 플라스틱기어의 마멸특성)

  • Kim, Chung-Hyeon;An, Hyo-Seok;Jeong, Tae-Hyeong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.11
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    • pp.1720-1729
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    • 2001
  • Wear characteristics of Nylon and acetal pinions against steel gears for different pitch line velocities was studied with a power circulating gear test rig under unlubricated condition. Specific wear rate was measured as a function of tooth number, module, tooth width and total revolution. The worn tooth surfaces were examined with a profile projector. The Nylon pinion showed lower specific wear rate than the acetal pinion. However, the Nylon pinion was fractured at high tooth loads, whereas the acetal pinion exhibited a steady wear behavior. The wear characteristics of Nylon pinion varied significantly with the Pitch line velocity. Wear occurred most severely at the tooth tip and the region immediately below the pitch line of pinion. The dominant wear mechanisms were adhesion and abrasion.

Wear Analysis of the Ti-N Coated Punch in Piercing According to the Volume of Production (생산수량에 따른 Ti-N 코팅 펀치의 마멸해석)

  • 황상홍;고대철;김병민
    • Journal of the Korean Society for Precision Engineering
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    • v.17 no.3
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    • pp.149-157
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    • 2000
  • Tool wear in the shearing process such as blanking, piercing and trimming is very important, because it has great effects on the dimensional accuracy, working efficiency and economy. Most of tools in the shearing process have the coated layer at surface fur good wear and corrosion resistance. When the surface of tool is teated, the wear Phenomena of coated surface layer and inner layer may be different. This paper describes a computer modelling technique by the finite element method in order to investigate the wear mechanism and to predict the wear profile of Ti-N coated tool in piercing process according to the volume of Production. Wear coefficients of the coated layer and inner layer are obtained through Pin-on-Disk wear test, respectively. To verify the effectiveness of the suggested technique, the technique is applied to wear analysis in piercing recess of piston pin and simulation results are compared with experimental ones.

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A Study of Clothing Design Preference & Satisfaction with the Fit of Ready-to-Wear Clothing for Older Men (노년기 남성의 의복디자인 선호도 및 치수적합에 대한 만족도에 관한 연구)

  • 서미아;이선희
    • The Research Journal of the Costume Culture
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    • v.8 no.6
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    • pp.864-870
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    • 2000
  • The purpose of this study were to investigate clothing design preference (style, color, fabric print, kinds of fabrics) & satisfaction with the fit of ready-to-wear clothing for older Men. For this study, the questionnaires were administered to 650 older men in seoul from June to August, 1998. Employing a sample of 504 data were analyzed by mean, frequency and percent. With respect to clothing design preference, they prefer suit the style of outdoor clothing on going-out. On distinguish clothing into formal wear & casual wear, the color preference due to seasons has difference in spring clothing. Regarding the degree of fabric pattern preference, nonpattern single color fabric has occupied in formal wear, pattern in casual wear. Regarding the degree of fabric preference, they take a serious view of shape preservation in formal wear, utility (washing, sweat absorption) in causal wear. Suit has the lowest satisfaction in the fit of ready-to-wear clothing. Sleeve length the lowest in the degree of satisfaction for each part.

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Methodology of Perform Design for Reducing Tool Wear in Cold Forging (냉간 단조 금형의 마멸 감소를 위한 예비성형체 설계방법)

  • 이진호;고대철;김태형;김병민;최재찬
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.164-167
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    • 1997
  • The die wear is one of the main factors affecting die accuracy and tool lifetime. It is desired to reduce die wear by developing simulation method to predict wear based on process parameters, and then optimize the process. Therefore, this paper describes disign methodology of preform for minimizing wear of finisher die in multi-stage cold forging processes. The finite element method is combined with the routine of wear prediction and the cold forging processes. The finite element method is combined with the routine of wear prediction and the cold forging process is analyzed. In order to obtain preform to minimize die wear, the FPS algorithm is applied and the optimal preform shape is found from iterative deformation analysis and wear calculation.

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Macroscopic Wear Characteristics of Ceramics under the Rolling Contact (구름접촉시 세라믹의 거시적 마모특성)

  • Kim, Seock-Sam;Koto, Kohji;Hokkirigawa, Kzauo
    • Tribology and Lubricants
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    • v.5 no.1
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    • pp.28-35
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    • 1989
  • The wear tests of ceramic materials in dry rolling contact were carried out at room temperature to investigate their macroscopic wear characteristics. Both point contact and line cootact were adapted in the wear tests of them. Ceramic materials used in these tests were silicon nitride, silicon carbide, cermet of TiN and TiC, titania, and alumina. The wear test of the bearing steel was carried out to compare to the wear test results of the ceramic materials. The results showed that the wear rate of silicon nitride was smaller than any other ceramic materials and bearing steel. In the steady wear, the wear volume of ceramic materials increases linearly with the rolling distance. It was also found from the experimental results that fracture toughness and surface roughness dominate the wear process of ceramic materials in dry rolling contact.