• The Journal of Korea Assosiation for Disability and Oral Health
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• v.3 no.2
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• pp.87-90
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• 2007

It's important that detect early caries of deciduous and permanent teeth to prevent dental caries and prevserve teeth, especially on proximal surface of deciduous teeth. The reason is that their prominent pulp horn lead to pulp treatment easily due to rapid caries progression. There are conventional exploring, visual inspection and radiographic exam for early caries detection. But, the standard method for diagnosing dental caries is subject and cavitation may be accelerated during exploring procedure. Caries can be diagnosed up to 40% mineral loss with radiograph. $DIFOTI^{(R)}$ (Digital Imaging Fiber-Optic TransIllumination) is diagnostic imaging system for early caries detection using fiber-optic illumination. It is possible that remineralize the tooth surface without tooth preparation and conserve the tooth structure by using $DIFOTI^{(R)}$.

• Polymer(Korea)
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• v.27 no.4
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• pp.307-312
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• 2003

Hollow fiber was prepared from the blend of a high density polyethylene (HDPE)/ultra high molecular weight polyethylene (UHMWPE). The changes in the morphology and mechanical property of the hollow fiber were investigated. The commercial product (Sterapore), having a high water permeability, was analyzed with viscosity measurement and FT-IR. The molecular weight of Sterapore was very high and its surface was coated with a vinyl alcohol/vinyl acetate copolymer. The content of UHMWPE in the HDPE/UHMWPE blend was limited below 10 wt%. In order to improve the dispersion of UHMWPE, a mineral oil should be introduced in the blend. The morphology and mechanical property of the hollow fiber of HDPE/UHMWPE blend were similar to those of the commercial product.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.5 no.2
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• pp.137-146
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• 1995

Twenty(20) large commercial buildings located in Seoul with friable sprayed-on surface insulation material on ceilings were investigated for asbestos content in bulk material by polarized light microscopy and for airborne fiber concentrations in buildings by phase contrast microscopy. In addition, such building-related variables as building age, numbers of traffic, airflow, surface conditions of the ceiling, temperature, and humidity were studied for any correlation with airborne fiber concentrations. The results were as follows: 1. Chrysotile asbestos was found in two bulk samples with 3-5% content and with <1%in one sample out of total 20 bulk samples collected. Glass fiber and mineral wool were the two major constituents of the bulk samples. 2. The ceiling surfaces were very friable in 16 buildings and were relatively hard in 4 buildings. The friability of the surface material was dependent upon the type and the amount of binder that had been mixed with the sprayed-on surface material. 3. Airborne fiber concentrations were log-normally distributed and the geometric mean(geometric standard deviation) fiber concentrations in the underground parking lots, inside buildings, and outdoor ambient air were 0.0063(1.97)f/cc, 0.0068(2.29)f/cc, and 0.0033(2.36)f/cc, respectively. 4. No significant relationship of airborne fiber concentrations and all building-related variables studied except humidity was found. The results of this study suggest that the sprayed-on surface insulation material found in some commercial buildings may possibly be contaminated with asbestos. Since most of the ceiling surfaces surveyed were very friable and poorly maintained and the airborne fiber concentrations were relatively high, there is a possibility of asbestos fiber contamination in these buildings, particularly at those buildings with asbestos-contaminated surface material. Since poorly maintained surface conditions were thought to be a source of high airborne fiber concentrations, there is a urgent need of a systematic operation and maintenance program. Further study of non-occupational asbestos exposure in general population utilizing advanced analytical technique such as transmission electron microscopy is highly recommended.

• Asian-Australasian Journal of Animal Sciences
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• v.8 no.2
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• pp.163-169
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• 1995

This study was conducted 1) to compare the nutrient content and mineral composition of the Philoppine indigenous sheep and goats diets when grazed in common pasture during rainy season, 2) to determine the influence of sampling methods on nutrient content and mineral composition of upland (UP) and lowland (LP) native pastures, and 3) to compare these two pasture types in terms of nutrient and mineral composition. Experiment 1 used sis esophageally fistulated animals, three each for sheep and goats. Weekly extrusa collection was done for a period of three months. Experiment 2 was conducted in UP and LP; these were sampled thrice by three methods, plucking, clipping and use of three esophageally fistulated sheep. Results of Experiment 1 indicated that the diets of sheep were greater in crude protein(CP; p < 0.01) and ether extract(EE; p < 0.05) but lower in crude fiber (CF) and acid detergent lignin (ADL; p < 0.05) than that of goat diets. All other nutrient fractions including mineral composition were not significantly different from each other. Significant findings of Experiment 2 were: CP content of UP was in the order fistulated > plucked > clipped (p < 0.05); CP content of LP was greater (p <0 .05) in fistulated and plucked samples; and ash content was greater (p < 0.05) in fistulated samples of both pastures. The CP of UP was different (p < 0.05) from each sampling method but the CP of LP and ADL of both pastures were greater (p < 0.05) in clipped samples. Most minerals either macro or microminerals were greater in fistulated samples of both pastures. Pooled data of the two pastures showed that LP had better nutrient characteristics and greater mineral composition. Based from this study, there were few differences between the diets of indigenous sheep and goats when grazed in common pasture. Also, sampling methods influenced the nutrient composition of indigenous sheep diets.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.3
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• pp.69-78
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• 2011

As recent concrete products changed to pursue high class, high quality, and high strength, as translucent concrete was developed to meet esthetic effects and exhibition purpose of structures. This study aims at introducing fabrication methods of various shapes of translucent concrete and evaluating feasibility of using mineral admixture such as fly ash, ground granulated blast furnace slag and granulated glass throughout experimental tests. As the result, it was found that compressive strength of translucent concrete block at 28 days is 32.2MPa and higher elastic modulus and Poisson's ratio than ordinary concrete block, which means that translucent concrete is widely applicable to structural purpose. Application of fly ash as a replacement of cement showed lower strength of 85 to 96% than Portland cement. In the meanwhile, ground granulated blast furnace slag showed 82 to 96% depending on the amount of replacement. The use of granulated glass as replacement of optical fiber was not applicable due to invisibility of light in concrete.

• Korean Journal of Plant Resources
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• v.15 no.3
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• pp.216-220
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• 2002

To obtain the basic information for the utilization of Salicornia herbacea L. as a raw material in food and chinese herbs, chemical components of it were investigated. Leaves and stems of S. herbacea L. from the western coast of Korea were used after dry and grinding with powder. Dietary fiber, total sugar and uronic acid contents of S. herbacea L. were 60.7, 15.2 and 2.6% , respectively. This result suggest that dietary fiber content of S. herbacea L. is so higher than others. Choline and betaine which are important as bioactive compound in body were detected with the value of 29mg/100g and 888mg/100g, respectively. Mineral components of S. herbacea L. were rich in Na (2880mg/100g), Ca (440mg/100g), K (930mg/100g) and Mg (356mg/100g).

• Journal of Animal Science and Technology
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• v.61 no.5
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• pp.278-284
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• 2019

This study was carried out to investigate the effects of seeding dates on the yield and feed value of whole-crop barley cultivated in paddy soil. The field experiment was conceived as a randomized block design performed in triplicate with seeding dates of Oct. 19 (T1 as treatment 1), Oct. 26 (T2 as treatment 2), Nov. 2 (T3 as treatment 3), Nov. 9 (T4 as treatment 4), and Nov. 16 (T5 as treatment 5) as treatments. The barley grown in all treatments was harvested on May 21 of the following year. Plant length, fresh yield, dry matter yield, and total digestible nutrient (TDN) yield were higher (p < 0.05) in barley with early seeding dates, whereas crude protein and ether extract were higher (p < 0.05) with late seeding dates. Crude fiber and neutral detergent fiber were highest in the T3 treatment and lowest in the T1 treatment. There was no significant difference between acid detergent fiber and TDN among the different seeding dates. Total mineral contents were higher in the order T1 > T2 > T3 > T4 > T5 (p < 0.05), whereas the total amino acid content increased significantly (p < 0.05) with a delay in seeding date. Free sugar contents (fructose, glucose, and sucrose) were higher with early seeding dates (p < 0.05). Collectively, the results obtained in this study indicate that it is favorable to seed soon after harvesting rice to increase dry matter and TDN yields and mineral and free sugar contents of whole-crop barley in the midlands of Korea.

• Journal of the Korea Concrete Institute
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• v.20 no.5
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• pp.619-626
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• 2008

There have been numerous studies to develop eco-friendly concrete. The attempt to reduce the amount of cement usage is suggested as one of the solutions for eco-friendly concrete. To reduce the amount of cement usage, the pozzolan-reaction materials such as ground granulated blast furnace slag, fly ash, and meta kaolin are widely used as the mineral admixture. Hwangtoh which deposited broadly in Korea is a well known eco-friendly material and the activated Hwangtoh with pozzolan-reaction can be practically used as a mineral admixture of concrete. Meanwhile, PET fiber made of recycled PET bottle is a type of recycled material, which can be used to control micro cracks in concrete. But the study about concrete mixed with recycled PET fiber is insufficient and the research of Hwangtoh concrete mixed with PET fiber is urgently needed presently. In this study, experiment and analysis flexural behavior of Hwangtoh concrete blended with recycled PET fiber are carried out. The results are discussed in detail.

• Computers and Concrete
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• v.18 no.5
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• pp.999-1018
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• 2016

Enhanced tensile properties of fiber reinforced concrete make it suitable for strengthening of reinforced concrete elements due to their superior corrosion resistance and high tensile strength properties. Recently, the use of fibers as strengthening material has increased motivating the development of numerical tools for the design of this type of intervention technique. This paper presents numerical analysis results carried out on a set of concrete beams reinforced with short fibers. To this purpose, a database of experimental results was collected from an available literature. A reliable and simple three-dimensional Finite Element (FE) model was defined. The linear and nonlinear behavior of all materials was adequately modeled by employing appropriate constitutive laws in the numerical simulations. To simulate the fiber reinforced concrete cracking tensile behavior an approach grounded on the solid basis of micromechanics was used. The results reveal that the developed models can accurately capture the performance and predict the load-carrying capacity of such reinforced concrete members. Furthermore, a parametric study is conducted using the validated models to investigate the effect of fiber material type, fiber volume fraction, and concrete compressive strength on the performance of concrete beams.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.225-229
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• 2001

There are about 41% (by weight) of scrap tires were pulverized to produce rubber powder and granules in the tire recycling industry of Taiwan. However, the reuse of the by-products, steel and fiber, of the scrap tires still needs to be improved. It is difficult to remove the remaining rubber on the surface of steel or fiber. This problem reduce the availability for further reuse of steel and fiber. In addition to the improvement of magnetic, gravity separation techniques or carbonization process, using cryogenic shredding process to separate rubber and fiber (or steel) had been used as another alternative. Cryogenic shredding process for scrap tires showed many advantages, the objective of this paper is to explore the mechanisms for the cryogenic shredding process of scrap tires. Cryo-SEM is used to investigate the topographic information, in-situ, from room temperature to -195$^{\circ}C$ . One square inch shredded tire chips are prepared for SEM study. The percentage of the shrinkage of rubber is also estimated, ca. 6.7%. Mechanisms of cryogenic shredding effects on the tire chips are discussed. The proper practice of cryogenic shredding process far scrap tires is also suggested.