• Composites Research
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• v.30 no.1
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• pp.35-40
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• 2017

In this study, natural fiber composites including flax fiber reinforcement was manufactured. It was tried to find optimum design of drill and machining factor for minimizing the damage during hole machining in natural fiber composites. Taguchi optimization was used for minimizing the number of experiments and evaluation of the effect of machining factor during hole machining in natural fiber composites. The experimental results indicate that the newly designed drill distributes cutting resistance well and minimizes surface roughness and produces fine surfaces. Developed new drill has been dispersed in the cutting resistance during processing, it was possible to obtain the smooth hole surface. Also, it was found that optimal rotational speed and feed rate of drill for hole machining.

• Journal of Fashion Business
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• v.26 no.4
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• pp.100-111
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• 2022

After the corona pandemic, when consumers choose clothes, the issue of sustainability has become a more important selection criterion. The eco-friendly functional fiber used in the study is a smartcell, which has functions such as UV protection, decomposition of harmful substances, deodorization, antibacterial and biodegradation. This eco-friendly functional fiber was dyed using five kinds of natural dyes to examine the color change according to dyeability and dyeing conditions. As natural dyes, gardenia, turmeric, sappan wood, lac, and indigo were used. For comparison with smartcell, rayon, a cellulose regenerated fiber, and wool fiber, a protein fiber, were dyed under the same conditions to compare dyeability and color. The study results are as follows. It was found that smartcell had superior dyeability compared to rayon and wool in gardenia dye and showed lower dyeability than wool when dyeing turmeric, sappan wood, and lac dyes, but showed superior or similar dyeability than rayon. In case of indigo dyeing, the dyeability of smartcell was the best when dyed once, but it was found that smartcell had a lower effect on repeated dyeing compared to wool or rayon. Therefore, smartcell has superior dyeability compared to rayon fiber in gardenia, turmeric, sappan wood, and lac dyeing, and in case of indigo dyeing, it is suitable for light dyeing. When smartcell is produced as textile fashion products, natural dyeing is actively introduced and commercialized, and it is hoped that this study can be a reference material.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.1
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• pp.140-144
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• 2010

In recent years there has been a growing interest for the use of natural fibers in composite applications due to their low cost, environmental friendliness, and good mechanical properties. The purpose of this study is to determine the characteristic of bending strength on bamboo fiber reinforced polymer composites. The parameters of RTM process depend on the weight ratio of bamboo fiber and resin, the number of bamboo ply and amount of hardening agent. Besides the existence of pore in composites according to vacuum time investigated a effect on mechanical properties of reinforced polymer composites. Test result shows that compressive strength was a maximum(approximately 1,840kgf/$cm^2$) value when weight ratio of resin was 12%.

• The Research Journal of the Costume Culture
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• v.9 no.4
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• pp.629-638
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• 2001

This study was intended to identify the desired image and fabric preference of woman college student for apparel and the relationship between these variables. Data were collected by questionnaire distributed to 260 woman college students through August to September of 2000. After eliminating incomplete questionnaires, 236 were analyzed. The most desired image was neat, and the most preferred fabric was natural fiber textile in fiber contents and light and soft in fabric sensation. The avoided image was masculine, and the negative sensation was heaviness. As a result of factor analysis, 7 factors -cute, intellectual, animate, neat, mature, sporty, sexy- were determined in image. And 8 factors -soft, durable, flat, rigid, light, bulky, heavy, pliable- were determined in fabric sensation. These factors explained large percentage of variance respectively. Multidimensional scaling was employed to analyze the relationship between desired image and fabric preference. Two dimensions were accepted to interpret the relationship. One of the results showed the closeness among the natural fiber textile, lightness, durability and natural image. And the short distance among the blended textile, elasticity, warmness and sporty image was presented.

• 한국연소학회:학술대회논문집
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• 2001.06a
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• pp.75-81
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• 2001

MCVD(modified chemical vapor deposition) used in making optical-fiber currently utilizes the hydrogen-oxygen burner as a energy supply source. To improve the productivity and to reduce the manufacturing cost of optical-fiber, a natural gas-oxygen burner has been developed. The manufacturing processes of optical-fiber consist of vapor deposition, collapse and drawing processes. Among these processes, the vapor deposition and the collapse processes are important in terms of improving the productivity and saving the production cost. The vapor deposition and collapse processes are performed by combustion heat and flame force supplied by a burner. So the flame force of the burner used in these processes is required to have an optimal and consistent value in order to allow uniform heating and collapse of quartz tube. In this regard, the momentum ratio of natural gas and oxygen has been optimally determined by modification of a burner and the inlet flow pass also has been modified.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.10a
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• pp.88-91
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• 2004

In this study, a number of natural fiber henequen reinforced polymer matrix composites were successfully fabricated by means of a compression molding technique using chopped henequen fibers surface-treated with different electron beam irradiation (EBI) dosages, thermoplastic poly(butylene succinate), thermosetting unsaturated polyester and phenolic resins. Their interfacial and thermal characteristics were studied in terms of interfacial shear strength, fracture surface, dynamic mechanical properties, dimensional stability, and thermal stability using single fiber microbonding test, SEM, DMA, TMA, and TGA. The results show that their interfacial and thermal properties significantly depend on the intensity of EBl treatment on the natural fiber surface.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.10a
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• pp.92-95
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• 2004

Interfacial shear strength (IFSS) of environmentally- friend natural fiber reinforced polymer composites playa very important role in controlling the overall mechanical properties. In this work the IFSS of Ramie and Kenaf fibers/epoxy systems were evaluated using the combination of micromechanical technique, microdroplet test to find out an optimal condition in accordance with final purpose by comparing to each other. Clamping effect on fiber elongation was determined as well. In addition, the mechanical properties of the natural fibers were investigated using single fiber tensile test and analyzed statistically by both uni- and bimodal Weibull distributions. Microfailure modes of different natural fiber structures were observed using optical microscope.

• Proceedings of the KWS Conference
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• 2005.06a
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• pp.262-264
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• 2005

This paper is concerned with a fracture strength study of composite adhesive lap joints. The tests were carried out on specimen joints manufactured hybrid stacked joints such as the polyester and bamboo natural fiber layer. The main objective of the work was to test the fracture strength using hybrid fiber composites with a polyester and bamboo natural fiber layer adjacent to the spew fillet of adhesive bonded joints and hybrid stacked joints. The results are presented using tensile-shear strength graph and finite element analysis. The failure mechanisms are discussed in order to explain that spew fillet at the end of the overlap reduces greatly the adhesive shear and effects the tensile-shear strength in hybrid stacked joints.

• Structural Engineering and Mechanics
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• v.55 no.1
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• pp.79-92
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• 2015

In this study, free vibration analyses of symmetric laminated cantilever and simply supported damaged composite beams are investigated by using finite element method (FEM). Free vibration responses of damaged beams are examined using Euler Bernoulli beam and classical lamination theories. A computer code is developed by using MATLAB software to determine the natural frequencies of a damaged beam. The local damage zone is assumed to be on the surface lamina of the beam by broken fibers after impact. The damaged zone is modeled as a unidirectional discontinuous lamina with $0^{\circ}$ orientations in this study. Fiber volume fraction ($v_f$), fiber aspect ratio ($L_f/d_f$), damage length ($L_D$) and its location (${\lambda}/L$), fiber orientation and stacking sequence parameters effects on natural frequencies are investigated. These parameters are affected the natural frequency values significantly.

• Journal of the Optical Society of Korea
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• v.19 no.2
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• pp.199-205
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• 2015

We investigated the effects of the thickness and doping concentration in p- and n-type poly-Si layers on the performance of a solar cell based on a carbon fiber in order to improve the energy conversion efficiency of the cell. The short-circuit current density and open-circuit voltage of the carbon fiber-based solar cell were significantly influenced by the thickness and doping concentration in the p- and n-type poly-Si layers. The solar cell efficiency was successfully enhanced to ~10.5%.