• International conference on construction engineering and project management
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• 2009.05a
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• pp.1272-1277
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• 2009

Since improved capacity for RC bridges has been required due to deterioration or increase in traffic, the deflection of cracked reinforced concrete slabs need to be reconsidered. Strengthening is known as the better way to improve capacity of bridges than reconstructing. In this paper, Fiber Reinforced Plastic (FRP) was introduced as one of the best strengthening methods for civil structures. The structures strengthened with FRPs can improve the strengthening capacity and serviceability. Therefore, CFRP sheet and Glass Fiber-Steel Composite Plate (GSP) in this research were used for strengthening slabs of RC bridges. Experimental data from the strengthening will be helpful to better understand the effect of the strengthening and effective flexural rigidity.

• Polymer(Korea)
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• v.39 no.1
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• pp.46-55
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• 2015

There is a limit for deforestation in order to keep the environmental cycle undisturbed. The heart of the paper is to replace the wood to a maximum extent to obtain a sustainable environment. This research aims at new natural composites in which treated hemp fiber used as reinforcement, synthetic cellulose used as particulate to improve the adhesion between matrix - fiber interface and Epoxy LY556 acted as matrix fabricated by hand layup technique. The density, water absorption, tensile properties, impact strength, hardness, flexural properties and compressive properties have been evaluated under ASTM standards and compare the results with existing materials such as wood, aluminium, etc., The composite hemp fiber reinforced polymer (HFRP) could be exploited as an effective replacement for wood and it would be suitable for automotive applications by comparing results.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.8
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• pp.2123-2138
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• 1994

A study on the dynamic mechanical properties of the high strength carbon fiber epoxy composite beam was carried out. The macromechanical model was used for the theoretical analysis of the symmetric laminated composite beam. The anisotropic plate theory and Bernoulli-Euler beam theory were used to predict the effective flexural elastic modulus and the specific damping capacity of laminated composite beam. The free flexural vibration and torsional vibration tests were carried out to determine the specific damping capacities of the unidirectional laminated composite beam. The vibration tests were performed in a vacuum chamber with laser vibrometer system and electromagnetic hammer to obtain accurate experimental data. From the computational and experimental results, it was found that the theoretical values with the macromechanical analysis and the experimental data of symmetric laminated composite beam were in good agreement.

• Proceedings of the Korea Concrete Institute Conference
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• 1991.04a
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• pp.111-116
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• 1991

In order to discuss the mechanical properties of carbon fiber reinforced polymer impregnated cement composties with silica powder, experimental studies on CFRC were carried out. The types of fiber used which are in CFRC are PAN-based carbon fiber and Pitch-based carbon fiber. To examine the effects of types, length, contents of carbon fibers and matrices, their properties of fresh and hardened CFRC were tested. According to the test results, compressive, tensile flexural strength of polymer impregnated CFRC were remarkably increased more than that of air cured and autoclaved CFRC. Also, polymer impregnated CFRC were considerably effective in improving thoughness, freezing-thaw resistance and loss of shrinkage compared with air cured and autoclaved CFRC.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.31 no.3
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• pp.83-89
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• 1999

Bast fibers of paper mulberry ( Broussonetia Kazinoki Sieb) were cooked with a weak alkaline salt, potassium carbonate which has been known as a major inorganic component of the traditional lye, and its cooking characteristics were investigated . The bast fiber was easily cooked by potassium carbonate. The pulp yield was rapidly decreased up to 20-30 mol of potassium carbonate, but the Kappa number was slowly decreased with increasing of potassium carbonate. The potassium carbonate pulps were easily defibered at low cooking chemical charge of 25mm on and high pulp yield of about 80%. These results were confirmed that pectin was easily removed during the potassium carbonate cooking. In contrast, when sodium carbonate was used as a cooling agent, the bast fiber was only partially defibered. Thus, sodium carbonate was a less effective cooling chemical of the bast fiber. The results of this experiment indicated that potassium carbonate could not only be used as a good cooling agent of bast fiber, but also as an alternative agent of sodium hydroxide.

• Textile Coloration and Finishing
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• v.1 no.1
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• pp.47-53
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• 1989

The effect of organic solvent in the dyeing of silk fiber by acid dye was investigated. Acetophenone and benzyl alcohol were shown to be the most effective for the rate of dyeing of silk fiber by Milling Cyanine 5R (C.I. Acid Blue 113), a milling type acid dye, but, with benzyl alcohol, the equilibrium dye uptake was much lower than that in the absence of it. In the presence of solvent, maximum dye uptake shifted to lower temperature than 6$0^{\circ}C$, while without solvent, it was shown at about $60^\circ{C}$. When dyed by Orange II (C.I. acid Orange 7) under same condition equilibrium dye uptake of silk fiber was lower than that for milling type acid dye, and in the presence of benzyl alcohol, still much lower uptake resulted. All these fact reveals that organic solvents in the solvent-assisted dyeing of silk fiber broaden micelle spacings too much, resulting in increased rate of dyeing, and decreased equilibrium dye uptake, contrary to wool.

• Journal of Nutrition and Health
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• v.27 no.10
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• pp.988-995
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• 1994

This study was performed to investigate the influence of various dietary fiber sources(rice bran, Chinese cabbage, radish, apple, laver, sea mustard) on the intestinal microflora in rats. Eight groups of rats were fed each experimental diets containing 5% of total dietary fiber for 4 weeks. Total viable counts and the numbers of Bifidobacterium, Lactobacillus, Clostridium, E. coli and Staphylococcus were determined by nonselective medium and various selective media. The number of Bifidobacterium(p<0.01) was higher in the apple and sea mustard groups than those in the other groups and the number of Lactobacillus(p<0.01) was lower in the radish group. A decrease in the intestinal population of clostridium was shown in the sea mustard group. The E. coli(p<0.01) and Staphylococcus(p<0.01) populations decreased in the apple group compared with other groups. These findings suggest that the apple fiber and sea mustard fiber are effective in improving intestinal flora of rats.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.319-324
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• 1999

This study is to investigate the properties on the load-deflection and fracture behaviors of the steel fiber reinforced concrete(SFRC) slab model specimens, Steel fibers of indent, crimp, and end hook shape were considered to reinforce the matrix under various mixing conditions and proportions. Initial cracking load, maximum load, and energy absorption capacity(load carrying capacity) of SFRC panel specimen increased with increase of steel fiber contents. And the plain concrete slab was fractured abruptly after maximum load but SRFC slabs were fractured smoothly by steel fibers in concrete matrix operated as cracking resistance force after maximum load. Indent, crimp and end hook shape steel fibers were effective in reinforcing the matrices but end hook type fiber were superior to indent and crimp type fibers.

• Carbon letters
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• v.9 no.2
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• pp.97-104
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• 2008

In the present study Sisal fiber obtained from the leaves of Agave sisalana has been chosen to validate its viability as an adsorbent for the removal of Nickel from aqueous solutions. The material was also surface modified and its effect on adsorption of Nickel was also studied. Agave sisalana fiber was found to be a cheap and effective adsorbent doing away with the need to activate the material therby reducing processing cost. The equilibrium studies indicated that the adsorption capacity of raw fiber and the surface modified fiber was 8.66 and 9.77 mg/g respectively with the Langmuir isotherm describing the adsorption phenomena better than the Freundlich and Temkin isotherm. The adsorption was found to be exothermic from the thermodynamic studies and the kinetics showed that the adsorption phenomena were second order.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.49 no.3
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• pp.75-81
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• 2012

In this paper, an efficient means to estimate the dispersion characteristics of active FSS (or ESS) is presented. We numerically investigate the effective permittivity and the transmission coefficient of 2D metal-fiber composites using linear-lumped impedance loading. We modify the GEC method which is applied to 2D fiber composite material with arbitrary fiber orientation. We show that by varying the impedance value it is possible to control the resonance frequency of the array as well as the bandwidth.