• Composites Research
• /
• v.35 no.3
• /
• pp.147-152
• /
• 2022

Low-temperature characteristics according to internal temperature conditions during rotational molding of Type 4 pressure vessel liners were studied in this paper. Since rotational molding has a sensitive effect on the formability of the liner depending on the temperature conditions, the temperature conditions for the polyamide used should be accurately set. The structural changes of polyamide as the liner material was analyzed the surface by atomic force microscope (AFM), and the crystallinity measured with a differential scanning calorimeter (DSC) is used to evaluate the change of the mechanical strength value at low temperature. In addition, the formability of the liner was confirmed by observation of the yellow index inside the liner. As a result, as the melting range of the internal temperature becomes wider, the yellow index shows a lower value, and the elongation and impact characteristics at low temperatures are improved. It was also confirmed that the structure of the polyamide was uniform and the crystallinity was high by AFM and DSC. These experimental results contribute to the improvement of characteristics at low temperatures due to changes in temperature conditions during rotational molding.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.19 no.5
• /
• pp.78-83
• /
• 2015

In the composite case, the first ply failure is considered total failure of the case. When the case is constructed by filament winding over a metal liner, the first ply failure does not necessarily mean total failure of the case. In this study, we compared the results through finite element analysis and burst test to predict the burst pressure of the hybrid case (filament-wound composite case with metal liner). Through it predicts the burst pressure of the hybrid case, we can determine the thickness of the metal liner and composite.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.6
• /
• pp.3089-3095
• /
• 2013

The headliner was made of polyurethane(PU) and glass fiber(GF) composite materials are widely used as a sound insulation material. A large amount of waste materials occurs as a by-product in the headliner manufacturing process. In order to efficiently reuse the headliner waste materials, separation process of the components are very necessary. According to the results of thermal analysis, weight loss showed increase in the order polyurethane foam> non-foaming polyurethane> non-woven fabric> 1st layer> glass fiber in the range of up to $400^{\circ}C$. Analysis of the DSC characteristics, HDPE, LLDPE, PP, and Master Batch by adding additives the wasted scrap. As a result, except for the PP, there was no exothermic transition due to the crystallization.

• Korean Journal of Food Science and Technology
• /
• v.38 no.6
• /
• pp.762-766
• /
• 2006

To improve water resistance of paperboard used to manufacture the corrugated boxes, effect of surface coating of the liner- board with Na-alginate was investigated by determining the optimum processing conditions such as a optimum alginate concentration for surface coating, plasticizer content, concentration of divalent cations their immersion times, For the surface coating of the liner-board, 2.5% Na-alginate solution was found to be the optimum concentration, and the concentration of glycerol used as plasticizer was effective when 35% alginate concentration was use was Used Immersion of the alginate coated paperboard for 3 min in a $CaCl_2$ solution improved the water resistance properties. As a divalent cation for the insolubilization of the alginate films, $Cu^{2+}$ was found to be as effective as $Ca^{2+}$. Among the platicizers tested, sorbitol was the most effective in reducing water vapor permeability and water solubility of alginate coated paperboard.

• The Journal of the Korea Contents Association
• /
• v.15 no.9
• /
• pp.384-394
• /
• 2015

The purpose of this study was to evaluate the push-shear bond strength between five commercial zirconia veneering ceramics and zirconia core cylinder, and to investigate the effect of biaxial flexural strength and zirconia liner glass treatments. The biaxial flexural strengths of the veneering ceramics were evaluated by a piston-on-three-ball test. The bond strengths between the Y-TZP cylinder and zirconia veneering ceramics were evaluated using the push-shear bond strength test. The data was analyzed using two-way ANOVA and Scheffe's test. The biaxial flexural strength of Cercon ceram kiss (CE) was higher than those of the other groups. The glass-treated and Triceram zirconia groups showed the highest value and the Creation ZI(CR) showed the lowest. In all groups, the liner glass treatment groups showed significantly higher push-shear bond strength than those without(P<0.05). The liner glass treatments of zirconia can improve the bond strength between the zirconia ceramic core and veneering ceramics.

• Elastomers and Composites
• /
• v.46 no.2
• /
• pp.102-111
• /
• 2011

The innerliner for a tire has excellent impermeability, air retention and good flex properties. The innerliner offers a role to improve performance parameter, such as air retention and tire durability that is of praricular importance for commercial tires. In order to improve the gas barrier properties of a innerliner, most of the innerliner rubbers, such as a halogenated butyl rubber(HIIR), brominated poly(isobutylene-co-isoprene)(BIIR), brominated polyisobutylene-co-paramethylstyrene(BIMS) are used as nanocomposites with nano fillers such as silicates, graphite etc. Innerliners based on nanocomposites may allow gauge adjustments and permeability reductions with potential improvement in tire durability. This article discusses potential innerliner permeablity reduction and compounding parameters on the properties of nanocomposite based innerliners.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
• /
• 2001.04a
• /
• pp.201-205
• /
• 2001

본 연구에서는 한지가공공정의 하나인 도침공정을 현대의 칼렌다링 공정과 비교 분석을 실시한다. 도침은 커다란 나무뭉치를 사용하여 반복적으로 여러 장이 겹쳐 진 한지를 두두림으로서 한지 표면을 평활하게 하며, 광택도를 높이는 효과를 볼 수 있다. 나무뭉치는 밑면이 평활해야만 할 것이다. 보통 한지 제조업자들은 경험 을 토대로 얼마만큼의 도침이 필요한지 결정하고 실시하곤 한다. 이러한 도침공정 에서 현대의 칼렌다링이 할 수 없는 중요한 공정이 존재한다면, 현대의 초지기에도 이러한 원리를 적용함으로써 효과적인 종이의 품질개선을 이룰 수 있는 여지가 충 분히 있다고 판단된다. 한지에 있어서 도침의 역할이 무었인지, 도침은 칼렌다링으 로 대치할 수 있는 지 둥을 비교 검토하였다. 도침공정 연구를 위하여 라이너지 한 종류, 백상지 한종류, 최근에 제조된 전통 한지 세 종류를 사용하였다. 라이너지와 백상지는 일반 제지공장에서 제조되는 방 식을 그대로 사용하여 기계 칼렌다를 통과한 샘플을 얻었으며 칼렌다를 통과하지 않은 라이너지와 백상지를 특별히 같은 지종에서 얻어서 실험을 실시하였다. 기계 칼렌다링을 하지않은 라이너지와 백상지 세 종류의 전통한지는 실험실 칼렌다를 통과시켰고, 또 각각에 도침을 실시하였다. 샘플들의 기본 물성과 처리조건을 표 1 에 정리하였다. 도침 공정에서 사용한 나무 뭉치의 무게는 약 64Kg 이며, 최대 높이 41cm 로 들어올려져 자유낙하에 의한 충격을 종이에 가하였고, 분당 충격횟수는 63회 였다. 라이너지는 도침 및 칼렌다에 의해 밀도가 서서히 증대되는 것을 볼 수 있었다 (그림 1). 도침은 칼렌다에 비해 밀도 증대에 효과적이지는 못하였다. 반면 백상 지에서는 도침이 기계 칼렌다나 실험실 칼렌다보다 현저히 크게 밀도를 증대시킴을 볼 수 있었다 (그림 2). 칼렌다는 종이를 높은 전단력과 압축력으로 변형시키는데 비해 도침은 단순히 압축 압력만을 종이에 가하는 것이 다르다고 볼 수 있는데, 라 이너지와 백상지가 같은 조건하에서 왜 이러한 큰 차이를 보이는 이유를 아직 알수 없다.

• Design Convergence Study
• /
• v.16 no.1
• /
• pp.97-109
• /
• 2017

Interest in the exterior design of buildings has increased in recent years. Demand for various architectural structures is increasing. However, domestic form liner and design are still limited. Thus, this research uses 3D printers to omit the existing mold production process. Use digital data to produce products economically using various materials. It can be hoped that extending the lifespan of the concrete structure will reduce the cost of saving costs. The purpose of this study is to utilize the 3D printers to develop the design of a suitable formative shape for the purposes of the concrete. In this study, 3D printed form enables the possibility that the actual application is practical. Consideration for the artistic design of the art line was proposed for the purpose of considering the use of concrete structures for concrete structures.

• Journal of the Korean Institute of Gas
• /
• v.17 no.6
• /
• pp.46-51
• /
• 2013

Composite cylinder is used by hydrogen fuel cell vehicles and natural gas vehicles because of high specific modulus, specific strength and fatigue resistance. composite cylinder has a seamless integrated liner and it is fully overwrapped with structural fibers of high strength carbon fibers in an epoxy matrix. In this study, filament winding pattern and autofrettage pressure design technique are presented considering structural weakness of knuckle and compressive residual stress. Presented methodology is verified by pressure cycling test of composite cylinders.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2000.04a
• /
• pp.25-25
• /
• 2000

가스발생기와 같이 로켓모터에서 추력이 아닌 기체압 형태의 에너지를 일정한 시간동안 얻고자 하는 경우, 로켓모터의 크기 및 추진제 충전율을 고려하여 그레인 형태를 단면 연소형으로 선택할 수 있다. 단면 연소형 그레인을 가진 로켓모터는 그레인의 연소시, 일찍 연소된 부분의 라이너가 추진제 연소 화염에 노출되면서 표면부터 서서히 분해가 진행되며, 분해물질의 일부는 추진제에 포함된 산화제 성분에 의해 산화되어 기체화 될 수 있다. 산화제 성분이 충분치 않은 경우에는 고체 입자 형태로 추진제 연소 기체와 함께 배출되며, 이는 일차연기(primary smoke)의 일종으로 볼 수 있다. 가스 발생기에서 얻고자 하는 기체는 고체 입자가 포함되지 않은 깨끗한 기체형태인 경우가 대부분이며, 따라서, 무연 라이너 및 내열재의 연구가 필요하다.