• Journal of Korean Society of Steel Construction
• /
• v.23 no.1
• /
• pp.125-135
• /
• 2011

To obtain a lower story height with a long span and better fire resistance, a new composite floor system using GFRP (glass-fiber-reinforced plastics) was proposed. This floor system consists of asymmetric steel with a web opening, a hollow core ball, concrete, and GFRP. To evaluate the flexural performance of the new composite floor system, an experiment was conducted. The test parameters were the presence of GFRP, the void ratio in relation to the hollow core balls, and the web opening. The test results showed that the resistance and stiffness of the specimen with GFRP were 10% higher than those of the reference specimen, and that fully composite action was accomplished up to the yielding point. After the attainment of the yield strength, the ductility of the specimen was reduced due to the stress concentration around the web openings. The slip between the concrete and steel beam, however, was small. Thus, in the design of the proposed new floor systems, it is desirable that the calculated resistance be reduced by 15%, for safety.

• The Bulletin of The Korean Astronomical Society
• /
• v.42 no.1
• /
• pp.34.1-34.1
• /
• 2017

The GMT-Consortium Large Earth Finder (G-CLEF) is the very first light instrument of the Giant Magellan Telescope (GMT). The instrument is a fiber feed, optical band echelle spectrograph that is capable of extremely precise radial velocity measurement, and has been being developed through the international consortium consisted of five astronomical institutes including Smithsonian Astrophysical Observatory (SAO), Observatories of the Carnegie Institution of Washington (OCIW), and Korea Astronomy and Space Science Institute (KASI). The Preliminary Design Review (PDR) for the G-CLEF was held in Cambridge, Massachusetts in April 2015. It is scheduled to have Critical Design Review (CDR) in March 2018. Flexure Control Camera (FCC) is one of the KASI's major contributions to the G-CLEF project. In this presentation, we describe the current critical design status, and structural and thermo-elastic analyses results on the G-CLEF FCC.

• Journal of Periodontal and Implant Science
• /
• v.23 no.2
• /
• pp.203-218
• /
• 1993

This study was designed to examine the effect of tetracycline application to the planed periodontal surgery of the experimentally induced periodontal disease in dogs. Modified Widman flap surgery was done and aqueous tetracycline (1%) was applied to the root surface for 5min, after which the wound was rinsed with saline, and flaps were coronally repositioned. Root surface ntoches were used as reference points. The animals were sacrificed 1 week, 2 weeks, 4 weeks, and 8 weeks after surgery, and block sections of tooth and surround tissue were processed for conventional light and electron microscopy. The results were as follows : 1. A more coronal position of junctional epithelium was observed in the area treated with tetracycline. 2. In the most of the tetracycline - treated teeth, the new collagen fibrils of connective tissue were oriented vertical/or oblique and parallel to the root surface. The vertical or oblique fibers were inserted into the denuded dentin matrix and contacted with exposed dentin collagen fibrils. 3. In the tetracycline - treated root, new cementum apposition, most of acellular extrinsic fiber cementum, was seen with bundles of oriented collagen fibrils incoporating into the cementum. 4. In the control and tetracyclin - treated teeth, bone resorption was observed at the alveolar crest in the 1 week groups.

• Journal of computational fluids engineering
• /
• v.20 no.4
• /
• pp.63-69
• /
• 2015

The thermal balance test in vacuum chamber for satellite structures is an essential step in the process of satellite development. However, it is technically and economically difficult to fully replicate the space environment by using the vacuum chamber. To overcome these limitations, the thermal analysis through a computer simulation technique has been conducted. The CFRP composite material has attracted attention as satellite structures since it has advantages of excellent mechanical properties and light weight. However, the nonuniform nature of the thermal conductivity of the CFRP structure should be noted at the step of thermal analysis of the satellite. Two different approaches are studied for the thermal analyses; a detailed numerical modeling and a simplified model expressed by an effective thermal conductivity. In this paper, the effective thermal conductivities of the CFRP composite structures are extracted from the detailed numerical results to provide a practical thermal design data for the satellite fabricated with the CFRP composite structure. Calculation results of the surface temperature and the thermal conductivities along x, y, z directions show fairly good agreements between the detailed modeling and the simplified model for all the cases studied here.

• Journal of Fashion Business
• /
• v.12 no.6
• /
• pp.46-60
• /
• 2008

Lyocell is a regenerated cellulosic fiber manufactured by an environmentally friendly process. The major advantages of lyocell are the excellent drape forming property, the genuine bulkiness, smooth surface, and high dry/wet tenacities. However, one drawback of lyocell is its fibrillation property, which would degrade its aesthetic quality and lower the consumer satisfaction. In our previous studies, lyocell was treated with epichlorohydrin, a non-formalin based crosslinker, to reduce its fibrillation tendency. To investigate the changes of physical properties upon ECH-treatment, the hand characteristics of ECH-treated fabric were observed using KES-FB system and the 3D-virtual sewing image of the fabrics were obtained using 3D CAD simulation system in this study. Since epichlorohydrin(ECH) treatment was conducted in the alkaline medium, the weight reduction was observed in all treated lyocell. The treated lyocell became light, smooth and flexible in spite of ECH crosslinker application. LT and RT in tensile property upon the ECH treatment did not change significantly, however, EMT and WT in the tensile property increased. The significant decrease in bending rigidity was resulted in all ECH-treated lyocell, which is the result of the weight loss upon the alkali condition of ECH treatment. The bending rigidity increased again in the ECH 30% treated lyocell, however, the B value is still lower than the original. Therefore, the ECH-treated lyocell would be more stretchable and softer than the original. Shear rigidity was also decreased in all ECH-treated lyocell, which would result in more drape and body fitting when it is made as a garment. The ECH-treated fabric showed the softer smoother surface according to SMD value from KES evaluation. The virtual 3D sewing image of the ECH-treated lyocell did not show a significant change from that of the original except ECH 30% treated lyocell. ECH 30% treated lyocell showed a stiffer and more puckered image than the original.

• Journal of Fashion Business
• /
• v.21 no.2
• /
• pp.105-112
• /
• 2017

A string wallcovering is a kind of textile wallcovering which is made of cellulose fiber yarn laminated on base paper. Compared with normal paper or PVC wallpaper, a string wallcovering is preferred continually in the interior design market, as it is not only environmentally friendly but it also has less cost on mass production without the weaving process and has a natural visual effect, excellent functionality such as thermo keeping, permeability, sound absorption. However, in the dyeing process, it is not appropriate to use plenty of energy such as water, electricity, steam or chemicals considering the environmental trend and the government policy plenty of energy such as water, electricity, steam or chemicals. Currently, a string wallcovering is made of raw white yarn and padding with direct dye or pigment which includes toxic elements, especially the use of direct dye is restricted in a part of the developed country due to inclusion of azo. In this study, we researched dyeing based on cold pad batch dyeing of a string wallcovering with reactive dyestuff. The peel strength and bending depth test confirmed that the optimum adhesive type and spread amount improved the water resistance of the string wallcovering. Also, pad batch dyeing with optimum reactive dyestuff enhanced the color fastness to light and rubbing in dry and wet conditions. Additionally, for improvement of color fastness to rubbing in a wet condition, the additional treatment finishing without soaping process which is used water. The results of this study can be used as basic data for environmentally friendly and energy saving of the textile wallcovering.

• Journal of Korean Society for Quality Management
• /
• v.44 no.3
• /
• pp.509-526
• /
• 2016

Purpose: We would like to find the alternative method for the weathering test on rubber coated fabrics and adhesive-coated fabrics for the military products, KS M 0706 (Sunshine carbon arc) to KS M ISO 4892-2 (Xenon arc). Methods: We measured the tensile strength of adhesive-coated fabrics and adhesive products treated with sunshine carbon arc and xenon arc during 100, 150 and 200 hours, respectively. All of the results were treated with statistical test, ANOVA method. We also validate the surface modifications caused by treatment method and time by using FT-IR ATR and, SEM. Results: In case of the thick adhesive-coated fabrics (app. 1 mm), there was no distinctive difference on tensile strength by treatment method and time. In case of the thin mask hood (app. 0.22 mm) and TENT (app. 0.5 mm), there was distinctive difference on tensile strength. Especially, carbon arc showed a huge lowering properties. We could validate the curing from light and moisture, and the functional group change from cross-linking and oxidation using FT-IR ATR. In case of IBS, there was a surface cracks on SEM images. In case of mask hood, there was no distinctive differences, except for a particle falling from decreased affinity between rubber and particles caused by carbon arc. Conclusion: We concluded that there was no problems for changing xenon arc weathering test with same treatment time on IBS, KM7, K21 and adhesive products. In case of TENT and mask hood, there was a difference in tensile strength in accordance with the change of the treated time and method.

• Parasites, Hosts and Diseases
• /
• v.47 no.2
• /
• pp.131-138
• /
• 2009

The present study surveyed the prevalence of natural infection of the sheep esphagus muscle with sarcocysts of Sarcocystis ovicanis and examined induction of protective immunity using UV-attenuated sporocysts. The overall prevalence of natural infection of the sheep was 95%. Infectivity of the collected sarcocysts was confirmed by shedding of sporulated oocysts after feeding infected esophageal tissues to dogs. To induce protective immunity, lambs were immunized 3 times (once a week) with $1.5{\times}10^4$ sporocysts exposed to UV-light for 30min (UV-30 group) or 60 (UV-60 group) min and then challenged with $1.5{\times}10^4$ normal sporocysts at the 3rd week post the 1st vaccination. These lambs showed high survival and less clinical signs of sarcocystosis than normal infected lambs. The attenuated sporocysts produced abnormal cysts; small in size and detached from the muscle fiber. These abnormalities were more obvious in UV-60 group than UV-30 group. Also, the $IFN-{\gamma}$ level and lymphocyte percentage were increased while the total leukocyte count was decreased in the UV-60 group compared with other groups. The high level of $IFN-{\gamma}$ may be an evidence for the induction of Th1 responses which may have protective effect against a challenge infection.

• Textile Coloration and Finishing
• /
• v.28 no.3
• /
• pp.189-194
• /
• 2016

The objectives of this research were to study the effect of salt-shrinkage finishing of silk on shrinkage degree and dyeing property of cochineal, and to investigate the efficacy of obtained results for imparting surface design effect on silk fabric. Ultimately it was aimed to suggest a technical process for developing natural dyed silk products with diverse design. Premordanted silk fabric was treated with $Ca(NO_3)_2$ solution(gravity: 1.45) at $90^{\circ}C$ for 1 min, washed, dried for further evaluation. The shrinkage of salt-treated fabric was calculated. The effects of salt treatment on the dye uptake of cochineal and colorfastness were investigated. The degrees of shrinkage were 10% and 3% for warp and weft, respectively. The salt treatment resulted in improving dye uptake of cochineal slightly. In addition, it improved colorfastness to washing and light. On the basis of the results, a technical process composed of premordanting, salt treatment and natural dyeing was suggested and using the process, two examples of textile design were presented. It can be concluded to impart various three dimensional surface design effect on silk fabric by applying salt-shrinkage finishing with combination of natural dyeing and mordanting.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.14 no.1
• /
• pp.79-85
• /
• 2006

CFRP(Carbon Fiber Reinforced Plastics) of the advanced composite materials as structural materials for vehicle, has a wide application in light-weigh structural materials of airplanes, ships and automobiles because of high strength and stiffness, However, there is a design variable to be considered in practical application of the laminate composite materials, these materials are vulnerable to transverse impact. This paper is to study the effects of stacking sequence and curvature on the penetration characteristics of composite laminate shell. They are stacked to $[0_3/90_3]S,\;[90_3/0_3]s\;and\;[0_2/90_3/0]s,\;[90_2/0_3/90]s$ and their interlaminar number two and four. They are manufactured to various curvature radius (R=100, 150, 200mm and $\infty$), When the specimen is subjected to transverse impact by a steel ball, the velocity of the steel ball was measured both before and after impact by determing the time for it to pass two ballistics-screen sensors located a known distance apart. The critical penetration energy of specimen A and B with less interfaces were a little higher than those of C and D. As the curvature increases, the critical penetration energy increases linearly because the resistance to the in-plane deformation as well as bending deformation increases, which need higher critical penetration energy. The specimen A and C have higher critical penetration energy than B and D because of different stacking sequences. We examined crack length through a penetration test. For the specimen A with 2interfaces, the longest circumferential direction crack length were observed on the first interface from the impact point. For the specimen B 4-interface, the longest circumferential direction crack length were observed on the second interface from the impact point.