• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.12
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• pp.28-37
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• 2019

Due to their flexible tailoring qualities, composites have become fascinating materials for structural engineers. While the research area of fiber-reinforced composite materials was previously limited to synthetic materials, natural fibers have recently become the primary research focus as the best alternative to artificial fibers. The natural fibers are eco-friendly and relatively cheaper than synthetic fibers. The main concern of current research into natural fiber-reinforced composites is the prediction and enhancement of the effective material properties. In the present work, finite element analysis is used with a numerical homogenization approach to determine the effective material properties of jute fiber-reinforced epoxy composites with various volume fractions of fiber. The finite element analysis results for the jute fiber-reinforced epoxy composite are then compared with several well-known analytical models.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2010.05b
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• pp.53-56
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• 2010

In this study, three kinds of cellulose fibers to crack reduction performance were evaluated and the results are as follows. Plastic shrinkage cracking is evaluated by the relative crack area, at all levels between $0.9kg/m^3$ and $1.2kg/m^3$, except for UF0.9% of upto50% showed are duction compared with Plain. In according to recommended amount of fiber in each area of the crack HF0.9>CEL1.2>UF0.6 effect of the order was more effective. While the impact strength of UF and CEL fibers until the final destruction are about five times the number of falls, HF fiber count drop was 10-18 time.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.04a
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• pp.111-115
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• 2005

Recently, natural fibers draw much interests in composite industry due to low cost, light weight, and environment-friendly characteristics compared with glass fibers. In this study, mechanical properties were evaluated for two extreme cases of jute fiber orientations, i.e. the unidirectional yarn composites and the felt fabric composites. Samples of jute fiber composites were fabricated by RTM process using epoxy resin, and tensile, compression, and shear tests were conducted. As can be expected, unidirectional fiber specimens in longitudinal direction showed the highest strength and modulus. Compared with glass/epoxy composites of the similar fabric architecture and fiber volume fraction, the tensile strength and modulus of jute felt/epoxy composites reached only 40% and 50% levels. However, the specific tensile strength and modulus increased to 80% and 90% of the glass/epoxy composites. The main reason for the poor mechanical properties of jute composites is associated with the weak interfacial bonding between fiber and matrix. The effect of surface treatment of jute fibers on the interfacial bonding will be examined in the future work.

• Journal of Pharmaceutical Investigation
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• v.39 no.2
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• pp.93-95
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• 2009

To compare the water vapor transmission rate (WVTR) of PVA/Dextran blended hydrogel obtained by European Pharmacopiea (EP) and Japanese Industrial Standards 1099 (JIS) method, the hydrogels with various PVA/Dextran rates were prepared and their WVTR values were then checked. As dextran in the hydrogel was increased, the WVTR of hydrogel was increased. The WVTR of hydrogels were 660-1500 and $730-1900\;g/m^2$-day in EP and JIS method, respectively. There were no significant differences between the WVTRs of the hydrogels obtained by EP and those obtained by JIS method. Thus, JIS method was recommended as a WVTR method of hydrogel due to relatively simpler and shorter time.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.4 no.4
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• pp.19-24
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• 2001

14 kinds of perennial flower sods, including 10 Korean native wild perennial flowers such as Lychnis cognata, Achillea sibirica, Sedum spectabile, Sedum takesimense etc. were made with basal sheets of nonwoven fabric or jute fabric. Growth of plants planted on bark was better than that of planted on soil of open area. The plants planted on bark also showed difference in growth rate by the kinds of used basal sheets. In general, the growth of plants was good when nonwoven fabric was used as basal sheet instead of jute fabric. When jute fabric was used as basal sheet, It was severely decayed during growth period resulting in great decreasing of root sticking capacity to basal sheet. It was shown that the procumbent plants such as Tymus quinquecostatus, Ixeris stolonifera, Sedum oryzifolium, Sedum polystichoides having lower plant height and better ground coverage ability compared with upright plants such as Sedum spectabile and Aster glehni were more suitable for floral sod production.

• Journal of Pharmaceutical Investigation
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• v.39 no.4
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• pp.263-267
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• 2009

The purpose of this study is to evaluate the efficacy of stipulated cleaning process, and the prohibition of cross-contamination and microbiological contamination, which inadequate cleaning in multi-production could occur, through cleaning validation of multi-purpose facility used to produce five biopharmaceutical products as sterile injection. After production of five biopharmaceutical products such as hGH, rhGCSF, rhEPO, rhFSH and rhIFN using vial filling machine, the cleaning validation such as residual analysis of active ingredients or human serum albumin, measurement of total organic carbon (TOC), residual analysis of detergent and microbiological contamination were carried out. In the case of rhGH and rhGCSF clean validations, drug residues were not detected. Furthermore, in the case of rhEPO, rhFSH and rhIFN clean validations, human serum albumin residues were not detected. At TOC (total organic carbon) analysis, all clean validations gave the TOC of about average 137.93%, not more than 150% of acceptance criteria. At sodium analysis for the checking of residues of cleaning agent, sodium residues were not detected. In sterility test, they showed no microbiological contamination of bacteria and fungi. Thus, this cleaning validation was determined as successful in protection of cross-contamination and induction of safety in multi-purpose facility.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.2
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• pp.112-117
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• 2016

This research compared the tensile performance of the vegetation mat, which was developed byu using the rapidly growing biodegradable plastic, Poly Lactic Acid(PLA), according to the biodegradation period. The test applied the method defined by Korean Standard KS. In the result of experiment using single-material PLA mesh and PLA plastic, the tensile strength and molecular weight were inverse-proportional to the 5 months of biodegradation period. The thickness of PLA mesh was increased by 11.2~13.4% while the tensile strenth of it was reduced by 32.4~55.4%. The tensile strength and molecular weight of PLA plastic were also reduced over time. However, the tension test of vegetation mat comprised of PLA mesh, non-woven fabric (including seeds), and jute net didn't have specific tendency.

• Journal of Conservation Science
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• v.25 no.3
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• pp.283-291
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• 2009

Methyl Bromide that was used as fumigation gas turned out to be the substance of destroying the ozone layer. For that reason, at the Montreal Protocol in 1987 the use of methyl bromide was forbidden starting 2005 in the advanced country. Also according to the 2007 Bali Protocolly methyl bromide is expected to be forbidden and therefore the purpose of this study is to find out the effects of substitution fumigation gas (Ethylene Oxide+HFC 134a, Methyl Iodide, Cyanogen and Argon) on the metal(silver, copper and iron), wood(oregon pine), pigment(yellow, red, blue, white and black), textile(hemp, ramie, jute, silk1 and silk2 / indigo, safflower and cork) and paper. After the fumigation test, ethylene oxide+HFC 134a did not have changes in the weight and color of the material itself before and after the experiment. On exterior alteration, color change occurred partly on paper and metal. Also, in most materials color change extent was 0.5 to 1.5 on the average and showed scanty difference. The materials after the fumigation test with methyl iodide did not show weight changes after the test. However, color changes more than 1.0 was shown in most of the materials especially in dyed textile material. In blue pigment, the discoloration on the surface could be seen by naked eyes. Fumigation test with cyanogen gas did not show weight changes and discoloration is more than 1.5 before and after the test. The weight changes of test materials with the argon gas was decreased about 3 to 6%. It can be observed that discoloration on paper was generated. Color changes can be seen on jute dyed with safflower and cork for two weeks with argon gas and the extent was 6.3 and 6.0.

• Journal of Conservation Science
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• v.37 no.2
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• pp.120-134
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• 2021

A Woolen carpet from the late Joseon Dynasty was unearthed in the process of repairing Seongjeonggak in Changdeokgung. Since relics are rarer than documentary records, the woolen carpet is highly valued as a relics. It is presumed to have been woven in the late 19th or early 20th century because there is a record of repairing Seongjeonggak in 1907. In the carpet, a pattern is made by inserting colored yarn dyed yellow and red onto a reddish-purple ground weave. The selvage of the woolen carpet used cotton thread, and jute is used for the warp and weft of the ground weave. The colored patterns is made of wool in the form of loop pile. Cut piles may appear occasionally when the colored yarn changes, but are almost invisible from the surface because they are pressed tightly with a shuttered weft. Making carpets with jute and wool is thought to be influenced by the Brussels carpets of the mid-18th century. Furthermore, the woolen carpet is torn and the pattern is completely unclear; however, it is understandable that the pattern is partially repeated. Microscopic and Fourier transform-Infrared spectrometer(FT-IR) analyses were performed for the above investigation. To identify the dyes used in relics, we compared them with natural dyed fabric samples based on chromaticity measurements and Ultraviolet/Visible spectrophotometer(UV-Vis) analysis. These analyses revealed that the woolen carpet's dyed green yarn did not use indigo, and reddish-purple ground weave is estimated to have used Caesalpinia sappan.