• Fire Science and Engineering
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• v.27 no.4
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• pp.41-46
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• 2013

The present study has been conducted to investigate the reaction kinetics and pyrolysis parameters for flame propagation analysis of furniture material components. TGA measurement for component materials such as MDF (medium density fiberboad) panel including coating material, synthetic leather and foam cushion are performed under maximum temperature of $600^{\circ}C$ and heating rate of $10^{\circ}C/min$. The results of TGA have shown that the peak temperature of MDF panel was $324^{\circ}C$ and the initial peak temperature of coating material decreased by $270{\sim}280^{\circ}C$. In the case of synthetic leather and foam materials, the reference temperature and reference rate depend on the type of polymer consisting the sample, the initial kinetic characteristics was classified into 2 categories of about $270^{\circ}C$ and $420^{\circ}C$ of reference temperature for the tested synthetic materials. The present study showed the pyrolysis parameters of reference temperature and reference rate proposed by Lyon to evaluate the pre-exponential factor and activation energy. The present study can contribute to improve the reliability of computational fire analysis and enhance the understanding of fire propagation phenomena based on the thermal properties study of material.

• Journal of the Korean Geotechnical Society
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• v.28 no.9
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• pp.97-106
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• 2012

In order to investigate mechanics of mixtures composed of sand and non-plastic silt, various specimens, with sand dominating the soil structure, and with varying fines content, fines content varying were produced. Isotropic consolidation tests were performed using high pressure triaxial test apparatus within high pressure levels where sand grain crushing happened. Experimental results showed that compressive curve of sand after yielding contracts to the NCL due to breakage of sand grains. Moreover, with the increase of fines content, coarse grains are surrounded by fines to form cushion effect, which made the breakage of coarse grains become difficult. Therefore, the maximum inclination of compressive curve became flatter and yield stress increased.

• Textile Coloration and Finishing
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• v.32 no.3
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• pp.176-183
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• 2020

In order to study wearable air cushion materials capable of responding to massive impact in high-altitude fall situation, high tenacity woven fabrics were bonded by heat only depending on various type of thermoplastic films and then mechanical properties were measured. Tensile strength, elongation, and 100% modulus measurement results for 4 types of films show that TPU-2 has higher impact resistance and easier expansion than PET-1. After thermal bonding, the combination with the highest tensile strength was a material with a TPU-2 film for nylon and a PET-2 film for PET, so there was a difference by type of fabric. The tear strength of the bonded materials were increased compared to the fabric alone, which shows that durability against damage such as tearing can be obtained through film adhesion. All of the peel strengths exceeded the values required by automobile airbags by about 5 times, and the TPU-2 bonded fabric showed the highest value. The air permeability was 0 L/dm2 /min. For both the film and the bonded material, which means tightness between the fabric and the film through thermal bonding. It is expected to be applied as a wearable air cushion material by achieving a level of mechanical properties similar to or superior to that of automobile airbags through the method of bonding film and fabric by thermal bonding.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.5
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• pp.605-611
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• 2016

Mg alloy sheet exhibits significant differences in tensile and compressive yield stress depending on the temperature, as well as variations in its hardening behavior. Such unusual behavior makes it difficult to simulate the forming process of Mg alloy sheets. Results of analysis tend to deviate significantly from the experimental data because commercial software do not completely implement the unusual hardening behavior, yield asymmetry and temperature dependent changes in the Mg alloy's material properties. In the previous study, an in-plane tension-compression cyclic tester was developed to predict the cyclic behavior of Mg alloy sheets at an elevated temperature of up to $250^{\circ}C$. A new constitutive equation was suggested to analyze the unusual behavior, and was implemented in the commercial software in the form of user subroutine. In this paper, a stamping process of Mg seat cushion panel for automotive parts was simulated using the experimental data and user subroutine. Based on the analysis, an optimal temperature condition was determined and a stamping die shape at each step was suggested in the non-isothermal stamping of Mg alloy sheets.

• Korean Journal of Applied Biomechanics
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• v.15 no.3
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• pp.1-7
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• 2005

Excessive pronation and impact force during running are related to various running injuries. To prevent these injuries, three type of running shoes are used, such as cushioning, stability, and motion control. Although there were may studies about the effect of midsole hardness on impact force, no study to investigate biomechanical effect of motion control running shoes. The purpose of this study was to determine biomechanical difference between cushioning and motion control shoes during treadmill running. Specifically, plantar and rearfoot motion, impact force and loading rate, and insole pressure distribution were quantified and compared. Twenty male healthy runners experienced at treadmill running participated in this study. When they ran on treadmill at 3.83 m/s. Kinematic data were collected using a Motion Analysis eight video camera system at 240 Hz. Impact force and pressure distribution data under the heel of right foot were collected with a Pedar pressure insole system with 26 sensors at 360 Hz. Mean value of ten consecutive steps was calculated for kinematics and kinetics. A dependent paired t-test was used to compare the running shoes effect (p=0.05). For most kinematics, motion control running shoes reduced the range of rearfoot motion compared to cushioning shoes. Runners wearing motion control shoe showed less eversion angle during standing less inversion angle at heel strike, and slower eversion velocity. For kinetics, cushioning shoes has the effect to reduce impact on foot obviously. Runners wearing cushioning shoes showed less impact force and loading rate, and less peak insole pressure. For both shoes, there was greater load on the medial part of heel compared to lateral part. For pressure distribution, runners with cushioning shoes showed lower, especially on the medial heel.

• Journal of Korea Society of Industrial Information Systems
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• v.5 no.3
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• pp.111-116
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• 2000

There are many recent monitor manufacturing firms not equipped with automatic checking system in their final process. And the check is based on the human perception, so the automatic checking system is needed for the consistency and the accuracy of the checking process to elevate the productivity and the quality. As the performance of computer systems and the vision systems has been increased, the cost for the system is reduced and their applicable algorithms have been developed. In this study we develop monitor checking system which is low-cost, fast, and easy to adopt by the small-scaled manufacturing films. The system is based on the computer vision techniques, and is equipped with the GUI interface and checking functions such as centering, yoke rotation, pincushion, sizing, brightness, and grayscale tracking. Monitor checking system developed in this study can be used in the final checking process thereby we expect the synergy effects both on the efficiency of production and on the reduction of the cost for the facility investments.

• Design & Manufacturing
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• v.13 no.3
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• pp.35-40
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• 2019

As the consumer market in the cosmetic, vehicle manufacturing and aerospace industries grows, the demand for manufacturing industries using on injection mold technology. Also, such manufacturing technology of metal machining is expensive, and the shape is limited. Cosmetic cushion fact products are divided into outer relevant to the exterior of the product and inner containers containing the actual contents. In the case of the inner container, it needs to be combined with the upper and lower cases. As environmental regulations are strengthened internationally, the use of a large number of component parts can result in significant losses in recycling and economics. Therefore, this study aims to perform injection molding analysis through injection molding simulation to develop a cushion fact container that can be recycled through the unification of products and materials using polypropylene to cope with environmental regulations. In the case of injection molding conditions, Injection Time(sec): 4.5, Cooling Time(sec): 13, Resin Temperature($^{\circ}C$): 240, and Pressure(MPa): 30 were determined. The results of injection molding simulation according to the two design methods were compared with the sync mark which shows the problem of filling and injection molding.

• Science of Emotion and Sensibility
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• v.24 no.3
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• pp.81-90
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• 2021

EMSCT (Electrical Muscle Stimulation Conductive Textile) is an electrical muscle stimulation pad that can compensate for ease of use and comfort, which are disadvantages of conventional hydrogel pads used in electrical muscle stimulation (EMS). With the concentration with SWCNT (Single-Walled Carbon Nanotube) and the number of impregnation processes, EMSCT was tested by giving conductivity to five fabrics (radirons, neoprene, spandex cushions, poly100%, and vergamo). The padding process with SWCNT was performed, and the alternating current measurement indicated that the most similar alternating current with hydrogel was the Vergamo fabric of SWCNT:=2:1. Furthermore, the usability evaluation of convenience, usability, and psychological satisfaction results in increased usability of EMSCT compared with conventional hydrogel pads.

• Journal of the Korean Institute of Gas
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• v.28 no.2
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• pp.7-16
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• 2024

This study presents investigation on the technical characteristics and field cases of the salt cavern storage method for large-scale hydrogen storage. The salt cavern storage method enables effective hydrogen storage compared to other methods due to the low porosity and permeability of the rock salt that constitutes the cavern, which is not likely to leak and requires a small amount of cushion gas for operation. In addition, there is no chemical reaction between rock salt and hydrogen, and multiple injection/withdrawl cycles can be performed making it effective for peak shaving and short-term storage. The salt cavern is formed in three stages: leaching, debrining, and filling, and leakage tests are conducted to ensure stable operation. Field applications are currently performing to meet industrial demand in the surrounding area of four sites in the UK and Texas, USA, and salt cavern operation is being prepared for energy storage in European countries such as Germany and France. The investigated results in this study can be utilized as a basic guideline for the design of future hydrogen storage projects.

• Journal of Korean Home Economics Education Association
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• v.18 no.3 s.41
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• pp.97-117
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• 2006

The purpose of this study was to investigate the teachers' recognition on the optimization of the educational contents of Clothing & Textiles in subjects of :he Practical Arts or the Technology & Home Economics in the course of elementary, middle and high schools. The statistical data for this research were collected from 203 questionnaires of teachers who work on elementary, middle and high schools. Mean. standard deviation, percentage were calculated using SPSS/WIN 12.0 program. Also. these materials were verified by t-test, One-way ANOVA and post verification Duncan. The results were as follows; First, The equipment ratio of practice laboratory were about 24% and very poor in elementary schools but those of middle and high school were 97% and 78% each and higher than elementary schools. Second, More than 50% of teachers recognized the amount of learning 'proper'. The elementary school teachers recognized the mount of learning in 'operating sewing machines' too heavy especially, the same as middle school teachers in 'making shorts': the same as high school teachers in 'making tablecloth and curtain' and 'making pillow cover or bag'. Third, All of the elementary, middle and high school teachers recognized the levels of total contents of clothing and textiles 'common'. The 80% of elementary school teachers recognized 'operating sewing machines' and 'making cushions' difficult especially. The same as middle school teachers in 'hand knitting handbag by crochet hoop needle', 'the various kinds of cloth' and 'making short pants'. The same as high school teachers in 'making tablecloth or curtain'. Fourth, Elementary school teachers recognized 'practicing basic hand needlework' and 'making pouch using hand needlework' important in the degree of educational contents importance. Middle school teachers recognized 'making short pants unimportant. High school teachers considered the contents focusing on practice such as 'making tablecloth and curtain' and 'making pillow cover or bags' unimportant. My suggestions were as follows; Both laboratories and facilities for practice should be established for making clothing and textiles lessons effective in Practical Arts in elementary schools. The 'operating sewing machines' which were considered difficult should be dealt in upper grade, re-conditioning to easier or omitted. The practical contents should be changed to student-activity-oriented and should be recomposed in order to familiar with students' living. It was needed to various and sufficient supports for increasing the teachers' practical abilities.