• Design & Manufacturing
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• 제10권1호
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• pp.26-30
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• 2016

In this study, it was investigated by comparing the experimental hemming by the 3 steps and 2 steps in order to stabilize the quality of the hemming process. In the experimental results, the three-step hemming superior to the two-step one and the dimensional stability of part that was made by the three-step on was high. When the second stage Hemming has been found that the deflection caused by the force to the wear of the punch becomes larger plane can be folded by the hemming crimping and crimp uncertain.

• 조명전기설비학회논문지
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• 제29권12호
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• pp.47-54
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• 2015

Normally, multiple socket-outlet is manufactured with soldered, welded permanent connection (termination). Because this procedure is very non-environmental and requires many labor forces, many companies skip this process. To solve this these problems, this research had to design permanent joint type multiple socket-outlet, develop safer multiple socket-outlet than is sold in markets. Progressing this research, we took 3 steps. First, we had to design device for fixing a frame suitable for multiple socket-outlet. Second, this multiple socket-outlet must pass fundamental standards through international standard (IEC 60884-1) and Korean standard (K 60884-1) tests. Third, it had to pass both several mechanical and electrical tests which is more strict than fundamental standards and vibration and impact tests following KS standards for enhancing its safety. After finishing 3 steps, we could obtain objective and fair data, develop environmental permanent joint type multiple socket-outlet without soldering crimped connection.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제34회 춘계학술대회논문집
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• pp.437-440
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• 2010

이 논문은 발사체 노즐에 사용되는 내열성 재료인 C/SiC에 대한 이방성 물성을 예측하는 방법으로, 평면 방향의 실험 데이터를 이용해서 9개의 엔지니어링 물성을 간단하고 효과적으로 계산하는 준 이론적 접근에 대해 설명하였다. 이 방법은 C/SiC 복합재료를 직조 보강재의 굴곡율에 따라 세 층으로 이상화 하여, 고전 적층 평판이론으로 계산한다. 평면 방향으로 실행된 실험 데이터와 직조 구조물의 굴곡율을 초기 데이터로 이용하며, 측정이 어려운 두께 방향의 물성을 효과적으로 얻을 수 있었다. 예제를 통하여 이 방법의 유용성을 증명하였다.

• Structural Engineering and Mechanics
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• 제33권4호
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• pp.429-446
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• 2009

Three-scale homogenization procedure is proposed in this paper to provide estimates of the effective thermal conductivities of porous carbon-carbon textile composites. On each scale - the level of fiber tow (micro-scale), the level of yarns (meso-scale) and the level of laminate (macro-scale) - a two step homogenization procedure based on the Mori-Tanaka averaging scheme is adopted. This involves evaluation of the effective properties first in the absence of pores. In the next step, an ellipsoidal pore is introduced into a new, generally orthotropic, matrix to make provision for the presence of crimp voids and transverse and delamination cracks resulting from the thermal transformation of a polymeric precursor into the carbon matrix. Other sources of imperfections also attributed to the manufacturing processes, including non-uniform texture of the reinforcements, are taken into consideration through the histograms of inclination angles measured along the fiber tow path together with a particular shape of the equivalent ellipsoidal inclusion proposed already in Sko ek (1998). The analysis shows that a reasonable agreement of the numerical predictions with experimental measurements can be achieved.

• 한국의류산업학회지
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• 제20권5호
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• pp.600-607
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• 2018

Polypropylene fibers, while having many advantages such as light weight, sweat fast drying, water-repellent, drainage, thermal insulation, anti-static property has a drawback in dyeing. In recent years, the development of dyeable polypropylene fibers has expanded its value in the textile market. The purpose of this study is to fabricate composite spun yarns using polypropylene, acrylic, rayon and wool and to analyze tensile properties, uniformity characteristics, bending properties, hairiness, and surface shape according to the degree of fineness and blended ratio. The specimens consisted of 100% polypropylene spun yarn pp30, pp40 and ppa(pp/acrylic), ppr(pp/rayon), ppw(pp/wool), 5 altogether sed in this study. The results of the study are as follows. The breaking strength of polypropylene spun yarn blended with rayon and acrylic was higher than that of 100% polypropylene spun yarn. The polypropylene spun yarn is higher the fineness been shown to decrease the breaking strength and elongation. The bending properties of polypropylene spun yarns were in the order of ppa>ppr>pp40>pp30>ppw. The unevenness of ppw, ppr, and ppa was higher than pp40 and pp30. With the exception of ppw with crimp properties, pp30 and pp40 were found to have a hairiness index greater than ppr, ppa. In the microscopic photographs of polypropylene spun yarn, pp30, which had the highest hairiness index, was found to have a thick yarn and a large number of hairs, and ppw had hairs of 3 mm or more protruding elongated outwardly.

• 한국염색가공학회:학술대회논문집
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• 한국염색가공학회 2012년도 제46차 학술발표회
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• pp.65-65
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• 2012

The air texturing공정은 노즐에서 전달되는 초음속 에어기류에 의해 overfeed를 수반하여 yarn속 fiber가 뒤얽혀 loop와 crimp를 발달시키는데, 고강력 고탄성율 고내열성 내절단성 등의 특성을 가지는 아라미드섬유를 에어 가공사로 가공 할 경우 가공 전 필라멘트 상태일 때 보다 표면에 생기는 loop로 인하여 촉감이 좋아지고 또한 타 소재와 접착 시 접착제 담지 성능이 향상 되어 접착력이 상승되고, 이를 통해 보강재로서의 기능이 강화되는 반면 역학물성이 기존의 아라미드 보다 저하되는 약점을 가지고 있어 최근 ATY 공정조건이 ATY 사의 구조와 물성변화에 미치는 영향에 대한 많은 연구결과가 발표되고 있다. 본 연구에서는 Aiki air jet texturing machine에서 $Heracron^{(R)}$ para-aramid(840, 1000d, 1500d)를 사용하여 ATY nozzle의 직경을 0.6, 0.75, 1, 1.2mm로 변화를 주어 12개의 para-aramid ATY 시료를 제조하여 이들의 섬도, 강신도, 초기탄성률, 열수축률 그리고 형태불안정성(instability)등의 물성변화를 분석하여 다음과 같은 결과를 얻었다. 노즐의 직경이 증가함에 따라 사 내의 filament간의 움직임이 자유로워 교락이 증가하고 루프가 형성되어 단위길이 당 mass가 커지므로 섬도가 미세하게 증가하는 것을 볼 수 있다. 또한 직경이 증가할수록 절단강도와 초기탄성률은 감소하고 절단신도가 증가하는 경향을 볼 수 있는데 이는 축 방향으로의 배열이 적어져 하중을 분담하는 portion이 감소하고 사의 loop형성이 많아짐으로서 상대적으로 인장력에 대응하는 fiber의 수가 적어지기 때문으로 사료된다. 이는 현미경 관찰로 확인할 수 있는데 직경이 증가함에 따라 사의 loop의 엉킴이 증가하고 filament가 조밀한 것을 확인할 수 있다. 직경 변화에 따른 건 습열 수축률은 1% 미만의 매우 낮은 값으로 영향을 받지 않는 것을 확인 할 수 있는데 para-aramid의 열적특성의 안정성에 기인하는 것으로 사료되며 ATY의 불안정성은 노즐 직경 증가에 따른 어떤 경향성을 찾아볼 수 없었지만 840d, 1000d, 1500d로 섬도가 증가함에 따라 사의 불안정성이 증가하였다.

• 펄프종이기술
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• 제31권4호
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• pp.76-83
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• 1999

This study was carried to investigate optimum conditions of charcoal added paper in making cigarette filter for the removal of smoke contents of cigarettes. We investigated the physical properties of charcoal added paper according to the ratio of pulps, the amounts of characoal , the weight of sheets and crimping conditions in dry method, and then analyzed the smoke contents of cigarettes. The results obtained were as follows. 1. Sw-BKP was higher than Hw-BKP in methylene blue absorption by UV test. 2. Charcoal had an effect on stiffness for decreasing factor greatly , while the addition amounts of Sw-BKP and high weigth of sheets increased it, and the interaction of weight of sheets and charcoal was higher than other factors. 3. Tear index decreased by charcoal addition greatly, on the other hand high weight of sheets and Sw-BKP/Hw-BKP ratio increased ter, and the interaction of pulps and chacoal acted on major factors. 4. We estimated crimp index with sensory evaluation , and charcoal hand an effect on decreasing factor in crimping greatly, while the interaction of weight of sheets and pulp ratio was higher than others. 5. In the case of charcoal added paper filter, tar removal efficiency of smoke contents was higher but about 6% than cigarette filter. Especially vapour phase(aldehyde) in smoke contents was removed greatly.

• Journal of Microbiology and Biotechnology
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• 제13권2호
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• pp.207-216
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• 2003

A number of different sources, such as composts, leachates, and pig feces samples, were collected from different pig farms in Korea, and several microorganisms were screened for their ability to deodorize the malodorous gases. Consequently, a novel malodorous gases-deodorizing bacterial strain, KJ-108. was isolated, because it was highly abundant in nitrate-supplemented minimal medium ($MM-NO_3^-$) under anaerobic culture conditions. Airtight crimp-sealed serum bottles containing $MM-NO_3^-$ , medium were inoculated with KJ-108. Nitrate concentration was decreased rapidly after 20 h of incubation, and incubation was carried out until nitrite production reached almost zero. Taxonomic identification, including 16S rDNA base sequencing and phylogenetic analysis, indicated that the isolate had $100\%$ homology in its 165 rDNA base sequence with Lactobacillus pentosus. Among the volatile fatty acids, acetic acid contained in large amounts in fresh piggery slurry was decreased by about $40\%$ after 50 h incubation with strain KJ-108. n-Butyric acid, n-valeric acid, and isovaleric acid were gradually decreased, and isobutyric acid and capronic acid were dramatically eliminated at theinitial period with the treatment. Moreover, NH, removal efficiency reached a maximum of $98.5\%$ after 50 h of incubation, but the concentration of $H_2S$ was not changed.

• Composites Research
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• 제32권5호
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• pp.206-210
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• 2019

직조 구조의 복합재의 쓰임이 자동차, 항공 산업 등 여러 분야로 확장됨에 따라, 직조 복합재의 신뢰성 문제 및 물성예측에 대한 필요성이 대두되었다. 본 연구에서는 직조 구조가 다른 복합재료의 물성 예측을 위한 유한요소해석을 수행하여 실험으로 얻은 정적 물성과의 유사성을 검증하였고, 효과적인 모델링 방법을 개발하였다. 직조 구조의 특성을 반영하기 위하여 모델링은 메소 스케일의 대표 체적 요소(RVE)를 이용하였다. 섬유 다발과 순수 기지를 분리하여 3차원 모델링을 진행하였다. 하신 파괴 기준(Hashin's failure criteria)을 적용하여 요소의 파괴 유무를 판단하였고, 해석 모델은 복합재에 적합한 점진적 파괴 모델을 사용하였다. 최종적으로, 직조 구조에 따른 복합재의 물성을 성공적으로 예측하여 본 모델링 및 해석 기법에 대한 적합성을 검증하였다.

• 한국염색가공학회지
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• 제33권2호
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• pp.87-95
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• 2021

In this study, the application of a medical compression sleeve of Moisture Responded Transformable(MRT) fibers to the treatment of lymphedema after surgery in breast cancer patients was investigated. MRT fibers were manufactured with PET and Nylon6 bi-component cross-section yarns, and compression sleeves of sleeves 1, 2, 3, and 4 were knitted in order of size, and then the physical properties and clinical tests were evaluated. As a result, the pressure of compression sleeve in wrinkle was the lowest in sleeve 1 with 3.81 kPa, and the highest in sleeve 4 with 5.22 kPa. Elastic recovery rate is that all parts except the top of the sleeve 1 exhibited 100%. The air permeability was good at 12.1 ~ 16.1 cm³/cm²/sec, and peeling was also comparatively excellent as grade 3. In addition, the weight of the compression sleeves 1, 2, and 3 decreased as 18.3 ~ 23.0 g/m² depend on size, while the compared sample was heavier with 17.39 ~ 32.61 g/m². In lymphoscintigraphy test, it was confirmed that the function of remaining lymph node was good in all patients. Although there were no differences between samples in skin irritation and tightness in wearing comfort, the manufactured sleeves showed better fit, lightness, fashion and breathability than the comparable sleeves.