• Tribology and Lubricants
• /
• 제38권3호
• /
• pp.109-114
• /
• 2022

This paper reports the development of an oil flushing system combined with a microbubble generator. Oil flushing plays a crucial role in regulating the lubricant's performance during the lubricant replacement process. Moreover, harmful contaminants, such as sludge, wear particles, and rust, from piping systems or lubrication system can be removed by oil flushing. Oil flushing aims to increase the system's efficiency using a dedicated flushing oil, increasing of the supply pressure and generating a vortex. In addition, it helps the mechanical system or equipment achieve peak performance and reduces the potential for premature failure. However, the contaminant-removal applications of existing oil flushing system are limited. In this research, we aim to improve the performance of oil flushing system by incorporating a microbubble generator, which uses the venture effect to generate microbubbles and mixes them with lubricant. The microbubbles in the blended lubricant remove contaminants from the lubrication system more effectively. Structural mechanics and fluid dynamics are analyzed through fluid-structure interaction (FSI) analysis, and the numerical analysis results are used for the designing the system. The magnitude of the maximum stress is investigated based on the pressure results obtained by the CFD analysis; through the CFD analysis, the mixing ratio of air (bubble) and lubricant is evaluated using the volume of fluid (VOF) model according to the working conditions.

• 패션비즈니스
• /
• 제27권6호
• /
• pp.66-84
• /
• 2023

Handbags are a part of fashion and while their significance and value are increasing, research on this topic is lacking. This study defines handbags and categorizes the materials used for making handbags, sewing methods, expression techniques, and terminologies related to accessories. A total of 1,743 handbags that were released from the Spring 2020 to Fall 2023, Ready-to-Wear collections by 8 selected brands (Hermes, Dior, Fendi, Chanel, Louis Vuitton, Prada, Gucci, and Alexander McQueen), were analyzed. Out of these, 732 unique designs, excluding those with only color variations, were studied. The most common sewing methods were 'Cut, sewing, and edge painting', 'Cylinder arm sewing', 'Cut, edge painting, and sewing', and 'Inverted seam', in that order. Slim strap designs primarily used the 'Cut, sewing, and edge painting' method, whereas the body, especially with narrow and hard leather, was best suited for the 'Cylinder arm sewing machine'. For expression techniques, the most frequently used methods were 'Quilting', 'Metal Eyelet', 'Embossing', 'Printing', 'Punching', and 'Weaving', respectively. The characteristics of each brand's production methods, expression techniques, and accessories were as follows: First, the exposure of logos and monograms is prominent. Unlike clothing, handbags often prominently feature the brand's logo or monogram. Second, signature quilting is a prominent feature. Quilting effectively conveys the brand's signature style, providing cushioning, volume, and pattern effects. Third, sustainable development is a growing trend. Brands are increasingly applying eco-friendly and socially responsible designs.

• 전자공학회논문지CI
• /
• 제45권3호
• /
• pp.47-57
• /
• 2008

최근에 에너지의 효율성이 좋고 대용량화가 쉬운 NAND 플래시가 센서 노드를 위한 차세대 저장소로 각광을 받고 있다. 현재 대부분의 센서 노드용 파일 시스템은 NOR 플래시 기반으로 개발되어 있으며 NAND 플래시에 적용할 수 있는 파일 시스템은 거의 존재하지 않는다. 대용량 NAND 플래시 메모리의 특성을 고려한 새로운 파일 시스템의 구축이 요구되지만, 센서 노드는 오직 $4{\sim}10$ KBytes의 매우 작은 크기의 메모리를 지원하므로 효율성이 뛰어난 파일 시스템을 구축하는 것은 매우 어렵다. 본 논문은 1 KBytes의 매우 작은 크기의 EEPROM을 부착하여 이러한 메모리 한계를 극복하였으며 자원의 효율성, 대용량의 지원 및 신뢰성을 고려한 새로운 파일 시스템의 설계 및 구현에 대하여 논한다. 파일 디스크립션을 위하여 EEPROM을 사용하며 효과적으로 플래시 메모리를 쓸 수 있는 방법과 wear-leveling을 할 수 있는 방법에 대하여 제안한다. 이는 획기적으로 페이지 갱신 횟수를 줄임으로써 에너지를 절약하고 보다 긴 시간동안 데이터의 수집을 용이하게 만들며 센서 노드의 수명을 증가시킨다.

• 한국의류학회지
• /
• 제41권1호
• /
• pp.84-97
• /
• 2017

Water vapor and thermal transmission properties of high emotional garments are important to evaluate wear comfort; in addition, the measuring methods of these properties are also critical for breathable and warm suit fabrics. In this study, the water vapor and thermal properties of composite yarn fabrics made of CoolMax, Tencel, and Bamboo fibers with filaments were measured and compared according to the measuring method. Water Vapor Transmittance (WVT) of the fabric woven by the sheath/core composite yarn in the warp direction was the highest due to the small staple fiber volume in the sheath/core yarn structure and high air voids in the sheath/core yarn fabrics. This property was also the highest in fabrics woven by bamboo staple yarns in the weft direction, and was the lowest on hi-multi filament fabrics. However, water vapor resistance ($R_{ef}$) of these fabrics by KSK ISO 11092 showed the opposite results to the water vapor transmittance method ($CaCl_2$ method); in addition, its correlation coefficient was low. The correlation coefficient between $R_{ef}$ and the drying rate was 0.719; therefore, the measurement mechanism of $R_{ef}$ is analogous to the drying property measurement. The thermal conductivity of the fabrics woven with compact staple yarn showed a high value; however, the hi-multi filament fabric showed low thermal conductivity. Therefore, fiber characteristics affect thermal properties more than yarn structure. The correlation between thermal property and moisture transport was also low. This study showed that: water vapor transmittance was active at the loose yarn structure, dry heat transport was vigorous at the compact yarn structure, and heat transport was affected more by fiber characteristics than yarn structure. In conclusion, sheath/core composite yarns were relevant to the high absorptive cool suit along with siro-fil and CoolMax/Bamboo staple yarns that were relevant to the heat diffusive cool suit.

• 한국재료학회지
• /
• 제1권4호
• /
• pp.221-228
• /
• 1991

본 연구는 computerdisk drive와 VTR head에 사용되어 지고 있는 ferrite head cores의 gap 형성에 적합한 유리의 봉착특성에 관하여 고찰하였다. 유리의 특성측정은 열팽창 계수, 미세경도, 내마모성을 측정하였으며 계면에서의 원소 농도분포는 WDS에 의해 관찰하였고 젖음성은 고온 현미경으로 측정하였다. 그 결과는 다음과 같다. 1. $PbO-B_2O_3$계 봉착용 유리에 있어서 PbO의 함량이 증가함에 따라 열팽창계수와 마모량이 증가하였으며 $B_2O_3$함량이 증가함에 따라서는 열팽창계수와 마모량이 감소하였다. 2. $PbO-B_2O_3$계 유리에 있어서 contact angle은 PbO함량에 주로 영향을 받는다. 3. 열팽창계수의 증가에 따라 봉착온도는 비례적으로 낮아지는 경향을 나타내었다. 4. Mn-Zn single crystal ferrite와 $PbO-B_2O_3$계 봉착용유리의 융착 계면에서의 확산은 ferrite성분이 glass측으로 소량확산이 이루어졌으며 봉착 열처리 시간에 따라서는 거의 영향을 받지 않았다.

• 한국산학기술학회논문지
• /
• 제12권12호
• /
• pp.5438-5442
• /
• 2011

자동차용 경량소결부품으로 사용하기 위하여 2712 Al 합금 및 2712에 세라믹스를 각각 10, 20, 33% 첨가한 소결체의 기계적 특성에 대하여 조사하였다. 그 결과, (1)모든 소결체에서 4~7%의 기공이 잔류하는 것을 발견하였다. (2)시효처리한 2712 소결체 및 10, 20, 33% 세라믹스 함유 소결체의 인장강도 값은, 12분 소결에서는 각각 165, 260, 256, 166 N/$mm^2$, 30분 소결에서는 각각 186, 229, 219, 202 N/$mm^2$로 나타나, 세라믹스를 10% 첨가하여 12분 소결한 경우가 가장 우수한 인장강도 값을 나타내었다. 또한, 소결체의 최대 연신율값 3.6%는 세라믹스를 10% 첨가하여 30분 소결 후 시효처리한 소결체에서 나타났다. (3)시효처리 후의 소결체 표면의 최대 겉보기 경도값 ($H_RF$) 97은 세라믹스를 10% 첨가하고 30분 소결한 경우에 나타났다. (4)가장 낮은 내마모량 값 $174{\times}10^{-3}mm^3$은 10% 세라믹스를 첨가하여 시효처리한 소결체에서 나타났다. 이러한 결과들로부터 세라믹스를 10% 첨가한 2712 소결체가 Al 엔진부품 제조에 가장 적합한 것으로 판단되었다.

• 한국산학기술학회논문지
• /
• 제21권11호
• /
• pp.219-225
• /
• 2020

본 연구는 요구되는 전압효율이 83% 이상인 풍량 10,000 ㎥/min급의 장수명 송풍기를 개발하기 위하여 송풍기를 설계·제작하여 송풍기 성능시험과 침식 실험을 통하여 개발품에 대한 성능을 확인하였다. Dust deflector의 영향을 살펴보기 위하여 각기 다른 길이의 Dust deflector를 갖는 5가지의 실험용 임펠러를 제작하여 침식 실험을 수행하였다. 가혹한 조건으로 실험을 수행하기 위하여 침식을 유발하는 분진 대체재로 1kg의 스틸 쇼트 볼(𝛷0.2 mm)을 사용하였다. 자체 제작한 폐루프 타입의 침식 실험 장치에서 160시간 동안 연속으로 가동 운전하여 실험하였다. Dust deflector에 의한 침식성능을 평가하기 위하여 마모두께를 측정하였다. 3차원 스캐너로 침식 실험 전 형상과 침식 실험 후 형상을 스캐닝하여 마모두께를 측정하였다. 모델 송풍기를 설계·제작하여 송풍기 성능을 시험한 결과, 모델 송풍기 측정값을 기준으로 개발 송풍기로의 환산 결과 전압 690.6 mmAq, 풍량 16,243.6 ㎥/min, 효율 83.6 %로 나타났다. 송풍기의 침식 실험 장치를 설계·제작하여 가혹한 조건으로 침식 실험을 수행하여 dust deflector가 부착된 송풍기인 개발 송풍기가 dust deflector가 없는 기존 송풍기에 비하여 임펠러 마모두께를 기준으로 190 % 이상의 개선 효과가 있는 것으로 나타났다.

• 한국의류학회지
• /
• 제33권4호
• /
• pp.634-643
• /
• 2009

The aim of this study was investigating the consumers' and apparel firm worker's awareness and reliability of the environmental friendly textile materials. The subjects of the questionnaire survey were general consumers(n=235) and workers at Korean apparel firms(n=236). The questionnaire was developed to measure the awareness and reliability on nine environmental friendly textile materials. The results showed that general consumers had a higher reliability on the function of the environmental friendly materials but had a lower awareness than the workers at the apparel firms. Women and subjects, who experienced in purchasing the environmental friendly products, had higher awareness and reliability of the environmental friendly textile materials than others. The workers at apparel firms had higher awareness of the environmental friendly textile materials than the general consumers, but the reliability on the function of the materials was relatively low. The reliability and awareness differed by the firms' major products and their jobs. The workers at the children's clothing firms and sportswear firms had higher level of awareness about the environmental friendly textile than the workers at the casual-wear firms. The workers' awareness on environmental friendly textile materials was differentiated by their jobs. The product developers and material buyers had higher awareness on the environmental friendly textiles compare to the workers of the sales or marketing division. These results imply that promoting environmental friendly textile material to the sales person is needed in order to increase the sales volume of the products.

• 한국컴퓨터정보학회논문지
• /
• 제22권9호
• /
• pp.115-123
• /
• 2017

The purpose of this study was to investigate the attitude and wearing effect of brassiere wearing in 20's female college students. Particularly, by exploring the necessity of wearing a brassiere, the research was carried out to make it possible to use it effectively in the development of brassiere for women in their early 20s. In early 20s, the type of wearing brassiere in female college students was analyzed as three types: function-importance type, inconvenience-accept type, and wearing inconvenient type. Function-importance type, the brassiere corrects the silhouette of the upper body, has a push-up effect that collects the breast, and it was thought that it would not allow the nipple point to fall. By wearing a brassiere, there is a lift-up effect that reduces the vibration of the breast due to movement and raises the bust. Inconvenience-accept type wears a brassiere so that the breast volume can be improved and the nipple point is not visible. And they strongly agreed that the brassiere would wrap my breasts well and calibrate the upper body silhouette to make my body look pretty. However, they felt that their bust was troubled when they wore it, and they thought that their brassiere would be out of order due to their movements, so they had to wear brassiere for beauty, but they were uncomfortable. The wearing inconvenient type was analyzed as a type that the cup part was lifted, the sweat was not absorbed, and the heat was uncomfortable. It is thought that it is necessary to develop an effective brassiere for the function of raising and collecting breasts based on the body shape of women in their early 20s.

• The Journal of Korean Physical Therapy
• /
• 제30권4호
• /
• pp.141-145
• /
• 2018

Purpose: Changes in the curvature of the vertebral columns of elderly women with increasing age causes various side effects and disorders. Therefore, this study was conducted to evaluate the effectiveness of the 8-figure scapular brace to improve pulmonary function and balance ability based on lung capacity and foot pressure by increasing the vertebral curvature. Methods: Seventeen elderly women with a forward head posture were selected. Women were asked to wear the 8-figure scapular brace and the forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) were measured, as were changes in foot pressure. Measurements were conducted three times each and the mean values were used for subsequent analyses. For static evaluation, we used the paired t-test to identify differences between pre and post values. Results: There was no significant difference in FEV1 and FVC before and after use of the brace (p>0.05); however, there was a significant decrease in forefoot pressure and an increase in rearfoot pressure following application of the brace (p<0.05). Conclusion: Application of the 8-figure scapular brace to correct vertebral curvature in elderly women influenced pressure distribution change from immediate effect body arrange of cervical and thoracic. However, wearing the 8-figure scapular brace may interfere with expansion of the chest and therefore respiratory muscle activity. Accordingly, it is necessary to apply appropriate treatment when wearing a scapular brace and to allow a sufficient intervention period while also providing therapeutic interventions such as posture correction or respiration training.