• Textile Coloration and Finishing
• /
• v.11 no.4
• /
• pp.8-15
• /
• 1999

Electroconductive fiber was obtained by acryl fiber treated with $CuSO_4$. The Properties and structure of fiber and fabric such as mechanical property, electrical conductivity, fine structure, electrification were investigated. The experimental results are as follows 1) The electrical conductivity of the conducting fiber was greatly increased but fine structure and physical properties were similar to acryl fiber 2) Fabric made by mix spinning with conducting fiber was shown great electrification effect. 3) In the mix spinning with conducting fiber, it was necessary to use different. finishing such as milled finish because stiffness of fabric made by mix spinning with conducting fiber was increased and elastic recovery was decreased. 4) The antimicrobial activity of electroconductive fiber blended wool was effective by Cu component for shake flask test.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.28 no.7
• /
• pp.873-881
• /
• 2004

This research was aimed to investigate the effect of enzyme and the addition of chelators on rotting of the Kenaf bast. Enzyme rotting was effective only when the chelators were added with the enzyme. EDTA was a more effective chelator than oxalic acid under 1% concentration. There was no difference in the rotting effect under different enzyme concentration levels, and under different treatment time and temperature. Therefore, it was found that enzyme rotting can be carried out with low enzyme concentration(0.125%) at room temperature. Retting time can be shortened when higher enzyme concentration and higher temperature are applied. Cellulose I structure of kenaf fiber did not change after enzyme rotting, and different enzyme concentration did not affect the crytallinity structure. Non-cellulosic matters such as hemicellulose, lignin, and pectin were present in the descending order in the enzyme rotted kenaf fiber, and there were no differences in their amounts due to enzyme concentration levels. There was no difference in the dyeabilities of kenaf fiber rotted with different enzyme concentration levels. Enzyme rotted kenaf fiber showed better cyeability when pectin, lignin, and hemicellulose were removed.

• Journal of the Optical Society of Korea
• /
• v.16 no.3
• /
• pp.247-255
• /
• 2012

Daylighting has a very effective role in reducing power consumption and improving indoor environments in office buildings. Previously, it was not under consideration as a major source of renewable energy due to poor reliability in the design. Optical fiber as a transmission medium in the daylighting system demands uniform distribution of light to solve cost, heat, and efficiency issues. Therefore, this study focuses on the uniform distribution of sunlight through the fiber bundle and to the interior of the building. To this end, two efficient approaches for the fiber-based daylighting system are presented. The first approach consists of a parabolic mirror, and the second approach contains a Fresnel lens. Sunlight is captured, guided, and distributed through the concentrator, optical fibers, and lenses, respectively. At the capturing stage, uniform illumination solves the heat problem, which has critical importance in making the system cost-effective by introducing plastic optical fibers. The efficiency of the system is increased by collimated light, which helps to insert maximum light into the optical fibers. Furthermore, we find that the hybrid system of combining sunlight and light emitting diode light gives better illumination levels than that of traditional lighting systems. Simulation and experimental results have shown that the efficiency of the system is better than previous fiber-based daylighting systems.

• Computers and Concrete
• /
• v.17 no.1
• /
• pp.67-86
• /
• 2016

Strengthening as well as correcting unsightly deflections of reinforced concrete (RC) beam may be accomplished by retrofitting. An innovative way to do this retrofitting that is proposed in this study utilizes turnbuckle to apply external post-tensioning. This Turnbuckle External Post-Tensioning (T-EPT) was experimentally proven to improve the serviceability and load carrying capacity of reinforced concrete beams. The T-EPT system comprises a braced steel frame and a turnbuckle mechanism to provide the prestressing force. To further develop the T-EPT, this research aims to develop a numerical scheme to analyze the structural performance of reinforced concrete beams with this kind of retrofitting. The fiber method analysis was used as the numerical scheme. The fiber method is a simplified finite element method that is used in this study to predict the elastic and inelastic behavior of a reinforced concrete beam. With this, parametric study was conducted so that the effective setup of doing the T-EPT retrofitting may be determined. Different T-EPT configurations were investigated and their effectiveness evaluated. Overall, the T-EPT was effective in improving the serviceability condition and load carrying capacity of reinforced concrete beam.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2003.05a
• /
• pp.367-372
• /
• 2003

Fiber Reinforced Cementitious Composite, DFRCC has strain hardening property with multiple crack in failed of compressive, tensile, bending force, concrete is not so that. But DFRCC could not use to the building element for which has not structural stiffness only has ductile property. DFRCC is used for repair only in recently. In that reason, we considered the concrete of light weight concrete, porous concrete, mortar complex with DFRCC. and DFRCC reinforced by fiber net, steel bar. In this study, results of experiment on complex method of concrete and DFRC were shown as follows; The complex methods of concrete lay on DFRCC, sandwich layer composition were effective for bending force depending on section size each layer, and reinforce DFRCC by fiber net, steel bar was effective method also.

• Current Optics and Photonics
• /
• v.2 no.3
• /
• pp.215-220
• /
• 2018

A novel porous-core hexagonal lattice photonic crystal fiber (PCF) is designed and analyzed for efficient terahertz (THz) wave propagation. The finite element method based Comsol v4.2 software is used for numerical analysis of the proposed fiber. A perfectly matched layer boundary condition is used to characterize the guiding properties. Rectangular air-holes are used inside the core to introduce asymmetry for attaining high birefringence. By intentionally rotating the rectangular air holes of porous core structure, an ultrahigh birefringence of 0.045 and low effective material loss of $0.086cm^{-1}$ can be obtained at the operating frequency of 0.85 THz. Moreover, single-mode properties, power fraction in air core and confinement loss of the proposed PCF are also analyzed. This is expected to be useful for wideband imaging and telecom applications.

• Journal of the Korean Society for Railway
• /
• v.12 no.5
• /
• pp.641-648
• /
• 2009

Concrete structures become more common in railway systems with an advancement of high speed train technologies. As the service life of concrete structures increases, structural strengthening for concrete structures may be necessary. There are several typical strengthening techniques using steel plate and fiber reinforced polymer (FRP) materials, which have their own inherent shortcomings. In order to enhance greater durability and resistance to fire and other environmental attacks, basalt fiber material attracts engineer's attention due to its characteristics. This study investigates bonding performance of basalt fiber sheet as a structural strengthening material. Experimental variables include bond width, length and number of layer. From the bonding tests, there were three different types of bonding failure modes: debonding, rupture and rip-off. Among the variables, bond width indicated more significant effect on bonding characteristics. In addition the bond length did not contribute to bond strength in proportion to the bond length. Hence this study evaluated effective bond length and effective bond strength. The effective bond strength was compared to those suggested by other researches which used different types of FRP strengthening materials such as carbon FRP.

• Animal Bioscience
• /
• v.34 no.6
• /
• pp.1014-1021
• /
• 2021

Objective: The aim of this study was to determine the effect of dietary ground licuri on lamb performance. Methods: Forty male lambs were used in a completely randomized design to test the effects of 0, 5, 10, and 15 g/kg of ground licuri added to diets. The trial lasted for 75 days. Intake, digestibility, physically effective neutral detergent fiber, and chewing activity were estimated. Blood samples were taken on day 45 to determine the concentrations of glucose, urea, non-esterified fatty acids, and triglycerides. Average daily gain (ADG) were determined on the last day of the experimental trial. Results: Licuri inclusion markedly increased dietary neutral detergent fiber and ether extract (EE) content, but it decreased dry matter (DM) intake. However, the intake and digestibility of EE linearly increased. The ADG decreased linearly (p<0.05) with licuri inclusion. Licuri had no effect (p>0.05) on the concentrations of blood metabolites; however, blood urea increased (p<0.05), while serum glucose decreased (p<0.05). Conclusion: The physically effective fiber of ground licuri is similar to Tyfton hay and licuri inclusion decreases lamb performance due to a decreased in DM intake.

• Journal of Technologic Dentistry
• /
• v.31 no.4
• /
• pp.37-43
• /
• 2009

This study evaluated the effect of concentration of glass fiber reinforcement on the flexural properties of auto and heat polymerized denture base resin. The test specimens($64{\times}10{\times}3.3mm$) were made of auto and heat polymerized resin(Vertex, Dentimax, Netherlands). Glass fiber(ER 270FW, Hankuk Fiber Glass, Korea) were used to reinforce the denture base resin. The 2.6%, 5.3% and 7.9% volume pre-impregnated fiber were located at the bottom of specimen. The test specimens(n=7) of each group were stored in distilled water at $37^{\circ}C$ for 50 hours before test. The flexural strength and modulus were measured by an universal testing machine(Z020, Zwick, Germany) at a crosshead speed of 5 mm/min in a three-point bending mode. The data was analyzed by one-way ANOVA and the Duncan's multiple range test(${\alpha}$=0.05). The difference of auto polymerized resin groups and heat polymerized resin groups were statistically analyzed by t-test(${\alpha}$=0.05). Glass fiber showed significant reinforcing effects on auto and heat polymerized resin. For flexural strength and modulus, auto polymerized resin was the highest in 7.9% volume, while heat polymerized resin was the highest in 5.3% volume. In this study, glass fiber at 7.9% volume ratio showed most effective reinforcing effect on auto polymerized resin and glass fiber at 5.3% volume ratio showed most effective reinforcing effect on heat polymerized resin in terms of flexural strength and flexural modulus.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.19 no.4
• /
• pp.49-56
• /
• 2015

Ultra-High Strength Concrete(UHPC) has ultra-high material performance including high strength and high flowability. On the other hand it is less ductile than high ductile fiber reinforced cementitious composite. This study investigated the effect of combination of steel fiber and micro fiber on the tensile behavior of UHPC. Four types of UHPC containing combination of steel fiber, polyethylene(PE), polyvinyl alcohol(PVA), and basalt fiber were designed. And then uniaxial tension tests were performed to evaluate the tensile behavior of UHPC according to combination of fibers. And density was measured to evaluate whether micro fiber induces unintentional high pore or not. From the test results, it was exhibited that PE fiber with high strength is effective to improve the tensile behavior of UHPC and basalt fiber is effective to increase the cracking and tensile strength of UHPC. Furthermore, it was also verified that micro fiber does not make high pore.