• Journal of the Korean Society of Clothing and Textiles
• /
• v.18 no.4
• /
• pp.549-559
• /
• 1994

The purpose of this study was to study accumlated residual soils which may be one of the causes for yellowing of worn cloths. Wear and wash tests of white cotton undershirts were repeated at 30 households sellected at random over a period of 60 days. Laundry conditions were similar to home laundry habits in a fact-finding survey, using a powdery heavy duty detergent containing no enzymes or enzymes. The subjects in this study were survey of laundry actual condition, the undershirts from prior to and after the final washing was measured residual soils, $L^*a^*b^*$ value and mellowness index of CIE system. D3ta were analysed by simple correlation analysis of wear and wash cycle, residual soils, whiteness The results obtained were summarized as follows: 1. Using pattern of washing machine, Presoaking was no singinificant differnece in general characteristics of survey respondent. Laundry frequency was significant difference in income level, occupation of housewives whether or not. Use of cold and hot water was significant difference in residence shape. 2. The analyzed consequences of recognition and actual behavior in connection with laundry were found variables each other to have independence or not. 3. Amount of residual sebum soils is using non-enzyme detergent were much more than in using enzyme detergent, increased linearly with increase of the number of wear and wash cycles. 4. Residual protein soils with increase of the number wear and wash cycles less than in laundering more easy than sebum soils. Since accumulated residual sebum soils were much more than residual protein soils. 5. Increase of residual soils was raised mellowness index and diminshed whiteness. yellowness index of residual sebum soils was higher than protein soils. If increase of whiteness will be incresed, amount of residual sebum soils will be decreased sebum soils. Because amount of residual sebum soils much more than protein soils, yellowness index of residual sebum soils was more higher than that of protein soils.

• Tribology and Lubricants
• /
• v.39 no.5
• /
• pp.203-211
• /
• 2023

This study experimentally investigates the effects of angular acceleration on the friction and wear performances of a gas foil thrust bearing (GFTB) using a typical GFTB with six pads. The outer radius of the bearing is 31.5 mm, the total bearing area is 2,041 mm² , and the bump foil and incline (ramp) height are both 500 ㎛. The newly developed GFTB test rig for measuring the friction torque and coefficient measures the axial load, drag torque, lift-off speed, and touch-down speed. The experiment is conducted for angular accelerations of 78.5, 314.2, and 328.3 rad/s² at axial loads of 5, 10, and 15 N, respectively. The test shows that the start-up friction coefficient increases with increasing axial load at the same angular acceleration, and the friction coefficient decreases with increasing angular acceleration under the same axial load. As the angular acceleration increases, the lift-off speed at the motor start-up increases, and the touch-down speed at the motor stop decreases. The wear distance of the GFTB for a single on/off cycle increases with increasing axial load at the same angular acceleration and decreases nonlinearly with increasing angular acceleration under the same axial load. The test results suggest that adjusting the rotational angular acceleration helps reduce bearing friction and wear.

• Korean Journal of Human Ecology
• /
• v.24 no.2
• /
• pp.255-266
• /
• 2015

In this study, we have developed the ergonomic pattern from the 3D human body reflecting cycling posture and extensibility of the stretch fabrics. Adjusting pressure level in the construction of athlete's tight-fitting stretch garments by reducing the original pattern is a challenging subject, which influence on the performance of the wearer directly. Therefore, in this study, relationships between the reduction rates of the 2D pattern obtained from the 3D human scan and resultant clothing pressure were explored to improve the fit and pressure exerted by reduced clothing pattern. Subjective wear sensations of the experimental garments were rated using a seven-point Likert scale on two consecutive days. While wearing the garments, subjects were asked to take five different postures including waist flexion, sitting and others. A Likert-type scale was used for the evaluation, with 7 points indicating the best fit in tight-fitting pants. Comparing 2/3T-pattern with T-pattern, the latter was superior to 2/3T-pattern in terms of adhere well to the waist and hip area in the 0.032 significance level. T-pattern was superior to 2/3T-pattern in terms of fitting and wear comfort. As results, the pattern obtained from the flexed body reflecting cycling posture already included the contraction and extension of the skin while cycling posture, so that the extra ease for movement and good fit was not need to be considered. The optimized reduction rates were determined with the proposed reduction rate, the resultant pressure range was within the range of $0.5{\sim}3.0gf/cm^2$ at eight locations on the body except front waist band and thigh band.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.13 no.5
• /
• pp.269-277
• /
• 2018

NAND flash memory has widely been used because of non-volatility, low power consumption and fast access time. However, it suffers from inability to provide update-in-place and the erase cycle is limited. The unit of read/write operation is a page and the unit of erase operation is a block. Moreover erase operation is slower than other operations. We proposed the Adaptive Garbage Collection (called "AGC") policy which focuses on not only reducing garbage collection process time for real-time guarantee but also wear-leveling for a flash memory lifetime. The AGC performs better than Cost-benefit policy and Greedy policy. But the AGC does not consider the operation characteristics. So we proposed the Advanced Adaptive Garbage Collection (called "A-AGC") policy which considers the page write operation count and block erase operation count. The A-AGC reduces the write operations by considering the data update frequency and update data size. Also, it reduces the erase operations by considering the file fragmentation. We implemented the A-AGC policy and measured the performance compared with the AGC policy. Simulation results show that the A-AGC policy performs better than AGC, specially for append operation.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.42 no.1
• /
• pp.40-57
• /
• 2018

This study investigated the design practice model based on the creative fashion designer's methodology in fashion education. 'The Design Cycle' was the criterion used to analyze the design method of Demna Gvasalia who is one of the outstanding contemporary designers. After that, this study's practice model was then developed and experimented to verify its effectiveness in design practice as based on Gvasalia's method where ready-to-wear products were firstly dissembled then re-constructed with new designs created based on re-constructed results. To test its effectiveness, a student oriented design workshop was held to extract design results through the practice model; in addition, the students also conducted a survey to evaluate the effectiveness of the method. According to the self-evaluation result, the participants generally accept the design efficiency through the distinctive process. An evaluation by three fashion experts was also conducted. Experts assessed that the model is recommendable for seniors having knowledges on 'Construction', it is appropriate to deal with the trickled-down copying trend that could promote student interest and generate separate results according to different visions. Therefore, it could be accepted that the applicability of this study's practice model was confirmed.

• Science of Emotion and Sensibility
• /
• v.21 no.1
• /
• pp.83-90
• /
• 2018

The purpose of this study is for fundamental research of meditation smart wear for physical and mental healing, and researching method for monitoring phase of meditation through textile by measuring the number of abdominal respiration when meditating. For this purpose, the research implemented Single Wall Carbon Nano-Tube (SWCNT) based strain gauges type textile sensor, considered reliability and validity of respiratory sensing, and analyzed efficiency of respiratory sensing based on body parts comparatively. The first preliminary experiment was to evaluate the performance of textile sensor through abdominal model dummy which open and shut of 5 cm repeatedly for 2 minutes at the rate of 0.1Hz in order to simulate abdominal respiration. It concluded signal efficiency between reference sensor(BIOPAC) and textile respiratory sensor appears statistically significant (p<0.001). The second experiment were conducted with 4 subjects doing abdominal respiration under same conditions, and after comparing the signal values between two sensors from 4 attached locations(around center and sides of omphali and phren), center of omphali and sides of phren were selected as suitable location for measuring meditational breathing as they showed large and stable signals. In result, this research aimed for implementing of the textile sensor for sensing meditational breathing of long respiration cycle, review of reliability and validity for sensing number of meditational respiration with the sensor and consideration of sensing efficiency by sensing location on body parts.

• The Journal of the Korea Contents Association
• /
• v.15 no.4
• /
• pp.104-113
• /
• 2015

Sports wear in relation to sports life is being developed in fashion industry with increasing leisure time. However, design development for swimwear including trend analysis is still required. In this research, we analyzed design trends in domestic social and cultural environment, and fashion design elements for the development for swimwear. We collected 9,549 picture images totally through 138 swimwear product catalogues in 1970s to 2014, and 8 web sites. We analyzed formative characteristics such as silhouettes, materials, colors, and textile designs. Because of the shorter cycle of social changes, and various trend, design changes of swimwear are getting diverse. Especially, color and textile design are remarkable. Also, new materials and printing technology make the design of swimming wear more comfortable and fashionable. This research would be a basic research for the design development of swimming wear.

• Proceedings of the KSR Conference
• /
• 2011.10a
• /
• pp.3059-3064
• /
• 2011

A Trolley line is a very important equipment among electric railway equipments since it contacts directly with pantograph and supplies electricity on the electromotive. Such it was thought that a trolley line need not to consider fatigue since the replace cycle by wear is shorter than the replace cycle by fatigue breakage. But, the bending fatigue breakage accidents occurred several times at the Shinkansen trolley line in East Japan Railway Company. Therefore, in case of a new developed trolley line, the evaluation for bending fatigue life became more important, But, since there are not an authorized fatigue test method and a testing device for the trolley line, the quantitative evaluation is difficult. In this study, we analyzed the load and environment condition of trolley line used in the actual spot and the developed testing device that can evaluate bending fatigue properties of the trolley line as simulating the real condition. The bending fatigue test of the trolley line was achieved using the developed testing device and estimated the fatigue life of trolley line and also, established the fatigue test process.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.17 no.2
• /
• pp.3763-3771
• /
• 1975

This study was attempted to investigate the changes of specific fuel consumption, compression pressure and power output, consequently to obtain basic data on farm kerosene engine. The samples which are used in this study are a 4 cycle water cooled korosene engine for the use of K6-CT83 power tiller and a 4 cycle air-cooled kerosene engine for the use of G5L-3A water pump. The Korean Industrial Standards (K.S)KS-B 6002 "Test code of small internal combustion engine" was referred in carrying out this study, and its results are as follows. 1. According to load increasing, the speific fuel consumption of the engines generally decreases, however, in case of 10% over-loading it increases. 2. As a result of full load consecutive operation, according to passing of operating time, the amount of wear generally increases, consequently the speific fuel consumption also increases, and inversly the compression pressure decreases. 3. The changes of specific fuel consumption and compression pressure were closely related with time of piston ring exchange, and periodically about 100 hours the engines show the increase of specific fuel consumption and the decrease of compression pressure. 4. After about 300 hours, although the engine had new piston rings, the specific fuel consumption increase, consequently the engine needs boring. In actual use, it is impossible to operate consecutively on full load, therefore the boring time of engine is expected to come later.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.24 no.5 s.176
• /
• pp.1305-1313
• /
• 2000

In a co-rotating scroll compressor, both scrolls rotate on their fixed axes contrary to the conventional orbiting type scroll machine. This implies fixed locations and directions of the gas pressure force and sealing force. Because the tilting moment is mainly caused by interplay between the resultant force of above forces and bearing reaction force, the variation during one cycle is relatively small. Under real operation, this moment is balanced by the restoring moment created by the reaction between the baseplate and thrust bearing or between the scroll tip and baseplate. If these reactions become too large, greater torque is required due to increased friction in addition to the wear of mating parts. Consequently, appropriate study and minimization of tilting moment is important in the design of scroll machines. In this study, taking into account of the small variation of tilting moment during one cycle, we minimize the moment and thrust bearing reaction force by a properly designed back pressure chamber. As a result, for both the driving and driven scrolls, the tilting moment and the reaction force of thrust bearing can be minimized. And the stability is improved for all cases.