• Journal of Advanced Marine Engineering and Technology
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• v.22 no.6
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• pp.827-835
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• 1998

The effects of recirculated exhaust gas on the wear of cylinder liner piston and piston rings have been investigated by the experiment with a two-cylinder four cycle indirect injection diesel engine operating at 75% load and 1600 rpm speed For the purpose of comparison between the rates of two cylinders with and without EGR the recirculated exhaust gas is sucked into one of two cylinders after the soot among exhaust emissions is removed by an intntionally designed cylinder-type scrubber equipped with 6 water injectors(A water injector has 144 nozzles of 1.0 mm diame-ter) while only the fresh air into another cylinder. These experiments are carried out on the fuel injection at a fixed $15.3^{\circ}$ BTDC timing. It is found that firstly the mean wear amount of cylinder liner with EGR is more increased in the measurement positions of the second half than of the first half and the mean wear amount without EGR is almost uniform regardless of measurement posi-tions secondly the wear rates of the first and second piston ring(compression ring)thickness with EGR are more than twice but the wear rate of oil ring thickness without EGR is more increased than that with EGR and finally the wear rate of piston skirt with EGR is a little bit increased but the piston hed diameter is rather increased owing to soot adhesion and corrosion wear and espe-cially larger with EGR.

• Tribology and Lubricants
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• v.33 no.5
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• pp.220-227
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• 2017

In this work, carbon nanotube and nano-size alumina particle are exploited as additive for lubrication experiment. We used pin-on-disk type tribometer to investigate the tribological characteristics of lubricants with respect to additives and rotational speed. We conducted more than 15 trials of tribotests for two hours for each specimen to obtain stable and accurate frictional force and to create measurable wear track on the substrate. We conducted tests at the boundary/mixed lubrication regime to evaluate the influence of additives on the tribological characteristics. We found that the friction coefficient decreased as the rotational speed increased and as additives were added. In particular, the reduction of friction by adding additives was more significant at low rotational speed than at high rotational speed. We speculate that the additives helped to separate and protect the two contacting surfaces at low speed, while the influence of additives was not significant at high speed since sufficiently thick lubricant film was formed. The wear of the substrate was also reduced by adding additives to the lubricant. However, in contrast to friction, the amount of wear at high rotational speed was less when alumina particles were added to the lubricant than the amount of wear at low speed. We speculate that the increased wear at low rotational speed is as a result of the intermittent abrasive wear caused by alumina particles with uneven shape, while the reduced wear at high speed is as a result of sufficient film thickness which prevented the abrasive wear.

• Fashion & Textile Research Journal
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• v.21 no.4
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• pp.459-467
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• 2019

Compression wear provides clothing pressure and affects how blood flows. Facilitating a blood flow is one of the most important functions of compression wear. The wearer's sensibility should be considered when designing compression wear. This study instructed participants to put on 5 types of sport compression wear with different pressure levels (CP-1 to CP-5), measured clothing pressure, blood flow level, blood flow rate, and surface temperature, and examined the pressure level that influenced blood flow through a subjective sensibility assessment. An experiment measured the clothing pressure of compression wear available in the market and found that the pressure ranged 0.6-1.1 kPa for the ankle, 0.7-2.3 kPa for the calf, and 0.9-1.9 kPa for the thigh. Meanwhile, blood flow levels and rates significantly increased when participants wore CP-1, which had the highest clothing pressure level, and CP-2 and CP-4 with middle-level pressure. After exercise, CP-2's surface temperature was the highest and revealed that wearing CP-2 facilitated blood flow. CP-2 was evaluated as most positive in the sensibility assessment and showed a clothing pressure of 0.67-1.82 kPa; its pressure for the calf did not surpass 2.0 kPa. Considering positive physical effect of compression wear on blood flow and subjective psychological effect on participants, CP-2 (0.67-1.82 kPa) would have the most suitable clothing pressure level among other types of the wear in this study.

• Fashion & Textile Research Journal
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• v.11 no.6
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• pp.947-952
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• 2009

The purpose of this study is to analyze skin wettedness($w$) used as the rate index of thermal comfort, and to evaluate the wear comfort of outdoorwear. Skin wettedness is widely used to express the degree of thermal comfort. If skin wettedness exceeds a certain threshold, the body feels damp and discomfort. An experiment which consisted of rest(30 min), exercise(30 min) and recovery(20 min) periods was administered in a climate chamber with 10 healthy male participants. Two kinds of outdoorwears made of 100% cotton fabrics (Control) and specially engineered fabrics having feature of quick sweat absorbency and high speed drying fabric (Functional) were evaluated in the experiment. The condition of climate chamber was controlled according to the thermal insulation of 4 kinds of experimental ensembles(E1~E4). Total sweat loss, sweat loss absorbed into clothing and skin temperature were measured. Skin wettedness was calculated from the ratio of evaporative rate to the maximal evaporative capacity. Skin wettedness of 'Functional' was lower than 'Control' in the 3 kinds of ensembles(E1, E2, E4) because the materials of 'Functional' were composed of quick sweat absorbency and high speed drying fabrics, water vapour permeability and waterproof fabrics.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.33-36
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• 2007

The majority of fly ash pipes in thermal power stations use steel pipes. This makes frequent replacement inevitable due to severe abrasion near the hot and curved section of pipes. Recently, there have been efforts to prevent this abrasion with lining techniques using ceramic or basalt on the inner wall of the pipe. This study uses composite and anti-wear material to maximize the anti-abrasion effects on the hot section of the pipe. The thickness of the abrasion layer was determined by the abrasion ratio of material found through the experiment; the thickness of the reinforcement layer was determined by micromechanics. Experiments were conducted on epoxy resins to test for heat and abrasion. Anti-abrasion test using particle impingement was intended to recreate realistic conditions when abrasion occurs within the hot section of an actual pipe. This study analyzes the abrasion ratio obtained from both the specimen experiment and from on-site measurement and provides evidence that a combination of composites and anti-wear agent can be used to create a fly ash pipe that is lower in costs and higher in quality than what is used currently.

• Journal of the Korean Society of Clothing and Textiles
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• v.13 no.3 s.31
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• pp.295-303
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• 1989

This study is to measure the thermal resistance of 7 types of Parka of different materials with thermal manikin and to compare their effects on physiological responses & subjective wear sensations. Following are the results obtained from the experiments 1) From the thermal manikin experiment, i) As an outer layer, although not significant, water proof fabric was warmer than water proof-vapor permeable fabric. ii) In case of insulating material, down was better for thermal resistance than polyester wadding of the same thickness. Moreover, as the down was thicker, it had more efficiency in thermal resistance. However, the marginal efficiency of thickness was found to be decreasing. 2) From the male-subject experiments, i) Chest temperature, mean skin temperature & microclimate temperature showed the same results on thermal resistance as those of the thermal manikin experiment. ii) Only during rest periods, there was a significant difference among 5 insulating materials in the sense of microclimate humidity. The almost same conclusion was obtained from the above experiments. Even the outer layer did not significantly affect thermal resistance & subjective wear sensation, insulating materials had a significant influence upon them. But in case of 3.5 cm down, it gave less comfortable than that of the thinner. Therefore the optional one for the best comfort & thermal resistance among 7 combinatins is the outer layer of water proff-vapor permeable & insulating material of 2.1 cm down.

• Journal of the Korean Society of Clothing and Textiles
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• v.9 no.2
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• pp.57-65
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• 1985

In the experiment with a basic material for the design of summer wear that comfort can be obtained in temperature, to get individual differences, clothing styles (slacks, skirt), material differences(T/C, cotton), and the contrast between when naked and dressed, when two healthy females were dressed four kinds of summer wear as an object of experiment under the regular warm temperature environmental condition (24, 28, 32, $36^{\circ}C$, $60\pm10\%$ RH), the measurement of physiological, phychological change was taken and the result goes as follow; 1. Mean skin temperature rose by clothing, body weight loss decreased below $32^{\circ}C$, thermal sensation changed toward low temperature by $2\~3^{\circ}C$. 2. Mean skin temperature, body weight loss, the lowest blood pressure above $32^{\circ}C$, under-clothing temperature, and thermal sensation increased when in slacks to be compared with when in skirt. 3. Ambient temperature had a great effect on mean skin temperature, body weight loss, respiration, clothing surface temperature, under-clothing temperature and humidity, thermal sensation, etc. 4. It was admitted that pulse, thermal sensation, comfort show different individuality. 5. It was recognized that the lowest blood pressure, clothing surface temperature, under. clothing humidity differ according to the kinds of clothing. 6. A comfortable ambient temperature in clothing summer wear was about $27\~28^{\circ}C$.

• The International Journal of Costume Culture
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• v.13 no.1
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• pp.51-61
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• 2010

The purpose of this research was to investigate the effects of clothing style and color of male casual wear on image perceptions and age evaluations. $4{\times}2$ (top color${\times}$trouser color) and $2{\times}3{\times}2$ (clothing style${\times}$clothing hue${\times}$clothing chroma) factorial designs were used as the experiment designs. Photoshop program was used to manipulate the clothing colors after creating photos of models wearing experiment clothing for stimulus. Subjects were 280 female college students from Seoul region and each subject responded to two stimuli. Factor analysis showed four factors of images of male casual wear; sociability, conspicuousness, softness and masculinity. Polo shirts were evaluated higher in sociability and softness than jumpers and nary blue trousers were evaluated higher in masculinity than beige trousers. High chroma clothing was assessed higher in sociability and conspicuousness than low chroma clothing. High chroma red jumpers displayed very sociable feel and low chroma blue jumpers displayed the lowest sociability. High chroma male clothing resulted in younger age perception but age was evaluated young when a black shirt was worn under the jacket when wearing a low chroma jacket.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2001.12a
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• pp.74-77
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• 2001

One of the most important technology in PA(Factory Automation) is to construct the diagnostic system for manufacturing process. To improve the productibility in the factory, the state of tools such as bite, drill, endmill should be monitored continuously. In this study, fuzzy logic was used to check the wear of drill in drilling process. The input variables to construct the fuzzy rules are cutting force and the rate of cutting force's change. The experiment was done with the fixed spindle speed and feed rate in cutting condition.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1998.04a
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• pp.335-341
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• 1998

In this study, the dynamic characteritics in various loading methods for wear tester were investigated experimentally. As for the dead-weight, the pneumatic, and the hydraulic method, the load control performance against external disturbances was estimated under the several loading conditions like the different sliding speed, the varied normal load, and the misaligument. The hydraulic loading method showed the most stable loading performance of all the loading methods in the experiment.