• Science of Emotion and Sensibility
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• v.10 no.1
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• pp.99-111
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• 2007

In order to identify tactile sensibility factors of traditional silk fabrics and to provide prediction models for the sensibility factors by mechanical properties, seventeen different traditional silk fabrics were evaluated in terms of both tactile sensation and sensibility by using a modified magnitude estimation line scale Gongdan and Newttong with lower values for surface roughness(SMD), bending rigidity(B), and compression resilience(RC) were rated as softer, smoother, fluffier, and more pliable in tactile sensation than any other traditional silk fabrics whereas Nobangju haying higher B, SMD, and tensile resilience(RT) was touched as crisper, more rustling, and springier. Three different tactile sensibility factors including 'Feminine', 'Natural', and 'Casual' were obtained significantly by grouping fifteen different tactile sensibility descriptors. In the prediction models sensibility 'Feminine' was explained positively by SMD, which was supported by the fact that both Gongdan and Newtton were perceived as more feminine. Sensibility 'Natural' that was felt stronger as for Myoungju and Sa was predicted negatively by both fabric thickness(T) and RT. Finally, RC, elongation at maximum load (EM), and T predicted sensibility 'Casual' negatively, which results in its higher factor scores for Myoungju and Shantung, respectively.

• Journal of the Korean GEO-environmental Society
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• v.18 no.8
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• pp.23-32
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• 2017

For exposed slopes, the weathering degree over time has a major effect on the engineering properties of rocks and the slope stability. Rocks are gradually changed by weathering into soil over time, and the resulting physical, chemical and mechanical changes of rocks affect the engineering stability of the slope. However, there are not many ways to objectively evaluate the weathering degree of a slope. In this study, therefore, to investigate the weathering characteristics of rocks, granite, gneiss and shale distributed in the Chungbuk region were sampled by weathering stage and changes in their component minerals and tissues were investigated. Furthermore, artificial weathering was induced using the freezing and thawing test and quantitatively investigated through porosity and absorption rate. In addition, the changes of microcracks due to artificial weathering were evaluated through box fractal dimension ($D_B$). Through mineralogical study the phase change of constituting minerals, the growth of secondary minerals, the development of micro-cracks and the fabric changes due to weathering were observed. The mineralogical, chemical and engineering evaluations of the weathering degree through the experimental results in this study are expected to be useful for analyzing the weathering characteristics and causes by rock type and for proposing a methodology to evaluate the degradation of physical properties comparatively and quantitatively.

• Composites Research
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• v.32 no.1
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• pp.65-70
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• 2019

The aircraft composites wing parts are usually integrated with adhesive or fastener. These laminated composites have weak interlaminar strength, which can lead to delamination. In order to compensate the disadvantages of laminated composites, it is possible to improve the strength, durability, shock and fatigue resistance by reinforcing the fiber in the thickness direction. In addition, using a single structure near-net-shape saves the manufacturing time and the number of fasteners, thus can reduce the overall cost of the composite parts. In this study, compression test, tensile test and open-hole tensile test are carried out for three structural architecture of 3D (three-dimensional) textile preforms: orthogonal(ORT), layer-to-layer(LTL) and through-the-thickness(TTT) patterns. Among these, the orthogonal textile composite shows the highest Young's modulus and strength in tensile and compression. The notch sensitivity of the orthogonal textile composite was the smallest as compared with UD (unidirectional) and 2D (two-dimensional) fabric laminates.

• The Journal of Engineering Geology
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• v.33 no.1
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• pp.69-83
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• 2023

Forest fires increase the risk of subsequent soil erosion and mass movement in burned areas, even under rainfall conditions below landslide alert thresholds, by destroying plants and vegetation and causing changes to soil properties. These effects of forest fires can alter runoff in burned areas by altering soil composition, component minerals, soil water repellency, soil mass stability, and soil fabric. Heat from forest fires not only burns shallow organic matter and plants but also spreads below the surface, affecting soil constituents including minerals. This study analyzed X-ray diffraction and physical properties of topsoil and subsoil obtained from both burned and non-burned areas to identify the composition and distribution of clay minerals in the soil. Small amounts of mullite, analcite, and hematite were identified in burned soils. Vermiculite and mixed-layer illite/vermiculite (I/V) were found in topsoil samples from burned areas but not in those from non-burned areas. These findings show changes in soil mineral composition caused by forest fires. Expansive clay minerals increase the volume of soil during rainfall, degrading the structural stability of slopes. Clay minerals generated in soil in burned areas are therefore likely to affect the long-term stability of slopes in mountainous areas.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.03a
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• pp.108-108
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• 2011

PLA 즉 폴리유산섬유는 옥수수를 발효하여 글루코오스(포도당)상태를 만든 후 젖산(유산, Lactic acid)으로 만들고 이것을 탈수, 축합반응시켜 polylactic acid로 만든 것이다. 생분해성이 있으므로 저탄소, 녹색성장의 모토를 대변하는 소재라는 이점이 있다. 구조는 에스테르기의 반복단위를 가지는 소수성 섬유로 벤젠환은 없으나 그 외 구조는 폴리에스테르와 비슷하며, 에스테르기가 존재하므로 분산염료와 수소결합하여 염착된다. 그러나 PLA는 융점이 $170^{\circ}C$, Tg $57^{\circ}C$로 내열성이 낮아서 염색온도, 열처리온도, 다림질에 제약이 있으며, 알칼리에 약한 단점이 있다. 따라서 PLA섬유는 낮은 염착량, 내알칼리성, 염착온도 때문에 염색 및 후가공 단계에 많은 사전 실험을 통한 조건 설정이 필요한 까다로운 섬유이다. 본 연구에서는 (주)휴비스의 PLA원사로 제직한 직물(경사:DTY 75/72SD, 위사:DTY 100/72SD, 조직:DOBBY) 생지에 대하여 열처리 시 장력의 유무, 온도, 시간에 따른 폭의 변화를 측정하여 수축률을 알아보았다. 또한, PLA직물을 온도별로 정련한 후 열처리하여 인열강도 측정을 통해 최적 전처리 조건을 조사하였다. 실험결과, PLA생지를 무장력 상태에서 열처리 시 수축이 심하게 일어나고, 장력이 주어져도 열처리 온도에 따라 수축의 정도에 차이가 나타났다. 열처리 시간은 30, 60, 90, 120초로 주었으나 큰 편차는 없었고, 경사가 위사보다 수축 정도가 더 컸으며, $130^{\circ}C$에서는 전체적으로 수축이 심하였다. 생지의 정련에는 인산에스테르계 정련제와 약알칼리인 탄산나트륨으로 조액하여 60, 70, 80, $90^{\circ}C$에서 10분간 처리한 후, Lab. tenter(Mathis, LTE)를 이용하여 110, 120, $130^{\circ}C$에서 30, 60, 90, 120초간 열처리한 다음, KS K 0535 펜듈럼법에 의거하여 인열강도를 측정하였다. 그 결과, 상기 정련온도에서는 인열강도에 영향을 주지 않았으나, 열처리 온도가 $130^{\circ}C$일 때 현저한 강도의 저하를 나타내었다. 실험조건 하에서 가장 적절한 열처리 조건은 $110^{\circ}C$, 60초로 사료된다. 따라서 PLA의 약한 내열성과 내알칼리성 실험결과, 강도나 수축 등 물성변화가 일어나지 않도록 열처리 온도의 제어에 주의가 필요함을 확인할 수 있었다. 실제 섬유가공 작업현장에서는 일반적으로 열처리기가 $180^{\circ}C$이상의 고온으로 고정된 경우가 많은데, 작업자들에게 PLA소재에 대한 사전주의 및 공정변경에 대한 주지가 요구된다.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.10
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• pp.543-550
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• 2016

Amine-type PP-g-VBC-EDA adsorbent, which possesses anionic exchangeable function, was prepared through photoinduced graft polymerization of vinylbenzyl chloride (VBC) onto polypropylene non-woven fabric and subsequent amination reaction using ethylenediamine (EDA). Adsorption characteristics of anionic nutrients on the PP-g-VBC-EDA adsorbent have been studied by batch adsorption experiments. The equilibrium data well fitted the Langmuir isotherm model, and the maximum monolayer sorption capacity was found to be 59.9 mg/g for $NO_3-N$ and 111.4 mg/g for $PO_4-P$. The adsorption energies were higher than 8 kJ/mol indicating anion-exchange process as the primary adsorption mechanism. The pseudo-second order kinetic model described well the kinetic data and resulted in the activation energy of 9.8-36.7 kJ/mol suggesting that the overall rates of $NO_3-N$ and $PO_4-P$ adsorption are controlled by the chemical process. Thermodynamic parameters such as ${\Delta}G^o$, ${\Delta}H^o$ and ${\Delta}S^o$ indicated that the adsorption nature of PP-g-VBC-EDA for anionic nutrients is spontaneous and exothermic. The PP-g-VBC-EDA could be regenerated by washing with 0.1 N HCl.

• Journal of Conservation Science
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• v.33 no.6
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• pp.443-456
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• 2017

The Geumran-gasa (Kasaya) and Jangsam of the monk Samyeong are historical relics and were designated as object No.29, a Buddhist costume of the Joseon Dynasty, by the National Folklore Cultural Heritage, in 1973. In 1984, after being treated for the purposes of washing and preserving the shape of the garments, the object was kept in the Temple Museum of Pyochungsa, as their holding institution. However, regular inspection conducted by the Cultural Heritage Administration in 2013 determined the need for a re-treatment. The Geumran-gasa had been originally made with 25 strips, but it had been separated into two parts and many pieces were lost. A part of the collar in the Jangsam was lost as well. Therefore, both relics needed to be restored. The re-treatment process involved pre-investigation, washing, reinforcement fabric dyeing, restoration, and fumigation. In particular, we focused on reinforcing the damaged parts and restoring the missing parts by applying advanced materials and methods in order to restore the original form as much as possible. This conservation is the result of the re-treatment of the cultural properties by replacing the old material used in past treatments and applying advanced methods under the basic principle of reversibility in conservation treatment.

• Journal of Conservation Science
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• v.27 no.2
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• pp.163-179
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• 2011

This study was to identify the material characteristics and provenance of the crucibles, potteries and roof tiles from the Wonsinheungdong site in Daejeon, Korea. Similar mineral composition of each samples showed by microscopic observation and X-ray diffraction analysis. However, wall thickness and mineral characterization of each ceramic artifacts are quite different. The pottery is characterized by thin wall with 0.5 to 0.7 cm and fine grained clay matrix. While the crucible and roof tile has thick wall with 1.3 to 2.5 cm, poorly sorted texture of many quarz, orthoclase and plagioclase whithin ceramic fabric. And large elonagated voids formed by hydrocarbone of straw during the firing and loose matrix obseved in crucible. All ceramic samples and ground soil of the site show similar mineralogical characteristics geochemical behavior and clay-mineralization degree. This indicates making that the soil is probable to be a raw material of all ceramic from the Wonsinheungdong site. Also, firing temperature of most ceramic artifacts are estimated as 850 of all ceramic from the Wonsinheungdong site. Also, firing temperature of most ceramic artifacts are estimated as 850 to $950^{\circ}C$ but hardest pottery fired high temperature between 1,050 to $1,150^{\circ}C$. The vitreous molten materials interpreted in slag included segregation of copper and tin. But it can not exclude the possibility that the glass molten material because observed reddish and greenish vitreous fine structure under microscopic.

• Composites Research
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• v.29 no.2
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• pp.73-78
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• 2016

In this paper, The concept of a wheel with carbon fiber composite is to replace the conventional material used for a wheel hub, such as plastic, with a disk-type hub made of carbon fabric and epoxy resin. The impact load from the ground under real conditions was considered; a low-velocity impact test was conducted to evaluate the impact performance of the carbon wheel and compare it with that of a conventional plastic wheel. This study applied a 70 J impact load as a test condition. The impact energy was controlled in the test by adjustment of height and weight of impactor. The use of a carbon disk wheel hub was confirmed to reduce weight and generate an excellent repulsive force at low energy under conditions similar to real driving conditions. The results showed that the maximum load increased proportionally depending on the impact load, but the growth of the maximum load was reduced at a 20 J impact load and tended to decrease at a 45 J impact load. The carbon wheel showed excellent properties ; the level of rebounding was 35.3% and 19.1% of the total impact energy at impact loads of 5 J and 10 J, respectively. On the other hand, the carbon disk wheel rebounded less than 5% of the total energy due to crack generation of the thin carbon hub for impact loads of more than 20 J.

• Journal of the Korean Society of Clothing and Textiles
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• v.13 no.4
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• pp.400-411
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• 1989

Moisture related properties of fabrics in dynamic modes are considered to be important in the judgement of the subjective comfort characteristics of clothing fabrics. In the current study, an attempt to improve the cobaltous chloride test method was made which has been known as a convenient screening test for dynamic surface wetness. The color changes of cobaltous chloride treated fabrics on the simulated sweating skin were calibrated against standard color strips. The standard color strips were made of all typs of test fabrics and installed inside of the test tubes containing a series of saturated salt solutions, which gives more quantitative informations on dynamic moisture transfer Influences of fiber types and finishes on dynamic moisture transfer in textiles were studied using a single layer of fabric samples. Fiber types included $100\%$ cotton, C/P 50/50, C/P 35/65. Durable press and soil release finished cotton and C/P 50/50 fabrics were also included. There were significant fiber effects on the dynamic moisture transfer. The order of time taken to reach to the specified $\%$ RH was C/P 35/65$100\%$ cotton fabrics. It was possible to detect significant finish effects by increasing the concentrations of cobaltous chloride solutions. The order of time taken to reach to the specified $\%$ R.H was durable press$100\%$ cotton, C/P 50/50, C/P 35/65 and $100\%$ PET were placed at the inner side of the outer layer and tested. It was shown that cobaltous chloride treated $100\%$ cotton fabirc was easier to detect color changes than C/P blend fabic in the double layer experiments. By placing test sample under the cobaltous chloride treated cotton fabrics, it was able to detect the differences among the test samples, some of which were known to be difficult in padding with cobaltous chloride solutions. Besides, the double layer method would provide with the broader application of the cobaltous chloride method in !uture, since it is possible to test the dynamic moisture transfer of clothing as worn.