• Title/Summary/Keyword: Materials property

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Research on Evaluation of Properties of PA6/PA66/GF Composite according to Injection Pressure and Simulation of Damping Performance (엔진마운트 브라켓용 PA66/GF 복합재료의 특성 평가 및 진동감쇠 성능 시뮬레이션에 대한 연구)

  • Seong-Hun Yu;Hyun-Sung Yun;Dong-Hyun Yeo;Jun-Hee Lee;Jong-Su Park;Jee-hyun Sim
    • Composites Research
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    • v.37 no.2
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    • pp.59-67
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    • 2024
  • Research was conducted on a PA material-based composite material manufacturing method for application to engine mount brackets. Engine mount brackets must have heat resistance, impact resistance, and damping performance. PA66 resin was used as the base material for the composite material. The glass fiber was used as the reinforcement material. The composite material was manufactured using the injection molding method. The thermal, mechanical, and morphological characteristics were analyzed depending on the content of glass fiber. 3D model was created using the property evaluation database of composite materials(input data). The damping performance of the generated 3D model was extracted as out-put data. The reason for evaluating the characteristics of PA-based composite materials and conducting simulations on the damping performance of 3D models of engine brackets is because product performance can be predicted without manufacturing actual automobile parts and conducting damping performance tests. As a result of the damping simulation, damping performance tended to increase proportionally as the mass fraction of the reinforcement increased. But above a certain level, it no longer increased and slightly decreased. As a result of comparing the actual experimental values a nd the simulated values, the approximate value was within ±5%.

Optimum Physical Property of Media for the Production of Small Potted Ardisia in Capillary Mat Irrigation System (매트재배에서 Ardisia 소형분화 생산에 적합한 배지의 물리성)

  • Lee, Dong-Soo;Kwon, Oh-Keun;Lee, Young-Ran;Lee, Yong-Beom
    • Journal of Bio-Environment Control
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    • v.18 no.4
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    • pp.316-325
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    • 2009
  • Adequate conditions of water content and aeration of container media are major environmental factors in the production of pot plant. This experiment was carried out to find optimum physical property of media for the production of small potted Ardisia in capillary mat irrigation system. The plant materials used in this experiment were Ardisia pusilla and Ardisia japonica. Seven substrates were formulated by blending perlite or fresh rice hulls at 20%, 40%, 60% (v/v) with sphagnum peat. Total pore space (TPS) increased by blending sphagnum peat with fresh rice hulls, but decreased by blending sphagnum peat with perlite. As fresh rice hull (FRH) and perlite content increased, air filled pore space (AFP) of substrate increased but container capacity (CC) decreased. Substrate blended with fresh rice hull was higher AFP than blended with perlite and the rate of increase was higher for FRH-containing substrate. As AFP increased, the $CO_2$ concentration in the pot decreased and the $CO_2$ concentration of substrate blended with FRH was higher than blended with perlite. The fresh and dry weight of Ardisia pusilla and A. japonica was the highest in the substrate contained 60% FRH, but the ratio of shoot dry weight to root dry weight was the lowest. The optimum total pore space, air-filled pore space, water holding capacity of substrate for the growth of Ardisia pusilla and A. japonica in the capillary mat irrigation system were 82.8%, 25.6%, and 57.2% respectively.

Changes in Chemical Property of Soil Affected by Termites (Reticulitermes speratus kyushuensis Morimoto) in Korea (국내 흰개미(Reticulitermes speratus kyushuensis Morimoto)에 의한 토양의 화학적 특성 변화)

  • Seong, Se Ha;Kim, Keun Ki;Hong, Chang Oh;Park, Hyean Cheal
    • Journal of Environmental Science International
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    • v.26 no.6
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    • pp.789-795
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    • 2017
  • Termites (Isoptera) are classified into approximately 3,106 species. In Korea, only one species has been identified, which is Reticulitermes speratus kyushuensis Morimoto. The termite, a social insect, is known to play an important role in nutrient cycling of the ecosystem, although some species of termites are well-known pests attacking wooden structures or any plant materials. However, there is a lack of research about termites in Korea, including aspects such the taxonomy, physiology, and ecology of termites. This study was carried out to provide valuable basic data on the ecological role of termites in an ecosystem in Korea for the future studies. For the experiments, soil and termite samples were randomly collected from Mt. Hwajang located in Jikdong-ri, Eonyang-eup, Ulju-gun, Korea between October 5 and 30, 2015. Analysis results showed that there were no significant differences in soil chemical properties between the soil samples just after air-drying and one year elapsed without any treatment. The treated soil with termites showed significantly higher than the soil without termite treatment. Chemical properties of total nitrogen, organic matter, available phosphate, pH, Calcium(Ca), Potassium(K) and Magnesium(Mg) in soil treated with termites were $1.11{\pm}0.3gkg^{-1}$, $43.3{\pm}12.4gkg^{-1}$, $27.4{\pm}2.9mgkg^{-1}$, $4.56{\pm}0.2$, $0.82{\pm}0.2cmol_ckg^{-1}$, $3.18{\pm}1.4cmol_ckg^{-1}$, $1.73{\pm}1.1cmol_ckg^{-1}$, respectively. The values of soil property of without termite treatment were $0.56{\pm}0.1gkg^{-1}$, $30.5{\pm}3.1gkg^{-1}$, $24.0{\pm}4.7 mgkg^{-1}$, $4.09{\pm}0.1$, $0.71{\pm}0.2cmol_ckg^{-1}$, $2.88{\pm}1.5cmol_ckg^{-1}$, $1.30{\pm}0.7cmol_ckg^{-1}$, respectively. These results suggest that inhabitation of termites could improve soil chemical properties in an ecosystem.

THE EFFECT OF HYALURONIC ACID ON EXPRESSION OF EXTRACELLULAR MATRIX PROTEINS AND BONE FORMATION IN RABBIT MANDIBULAR DISTRACTION OSTEOGENESIS (가토 하악골체부 신연 골형성술시 하이알우론산이 세포외 기질 단백질의 발현과 골형성에 미치는 영향)

  • Park, Ki-Nam;Song, Hyun-Chul;Jee, Yu-Jin;Yoo, Jin-Young
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.31 no.2
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    • pp.116-129
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    • 2005
  • Distraction osteogenesis is a new bone formation technique. There is a advantage of the environmental adaptation when distraction force is applied to the gap between osteotomy lines. But it has a disadvantage of long-term wearing of the appliance and long consolidation period. Therefore we make an effort to reduce it and repair normal function. Extracellular matrix proteins have a function to control the cellular growth, migration, shape and metabolism. In these, hyaluronic acid is a member of polysaccharide glycosaminoglycans (GAGs) and has a important function as bone formation and osteoinduction property. Purpose : In this experimental study in rabbit mandibular distraction osteogenesis, we investigated the bone enhancing property of hyaluronic acid and the expression of extracellular proteins such as osteocalcin and osteonectin. Materials and Methods : The experimental study was carried out on 24 Korean male white rabbits (both mandibular body, n=48). Distraction group was divided to distraction experimental (A, n=16) and distraction control (B, n=16) by the application of hyaluronic acid (Hyruan, LGCI, Seoul, Korea). Normal control group (C, n=16) was only osteotomized. After 5 days latency, distraction devices were activated at a rate of 1.4 mm per day (0.7 mm every 12hours) for 3.5 days. Animals were sacrificed at postoperative 3, 7, 14, and 28 days. H&E stain and immunohistochemical stain was done on decalcified section. Additionally RT-PCR analysis was done for the identification of the expression of osteocalcin and osteonectin. Results : The bone formation in distraction experimental group was much more than that in distraction and normal control group at postoperative 28 days. In immunohistochemical stain, osteocalcin was enhanced at only postoperative 14 days, but osteonectin was not different at each post-operation days. In RT-PCR analysis, osteocalcin was not different at each post-operation days, but osteonectin was strongly expressed in distraction experimental group at postoperative 7 days. The expression of osteocalcin and osteonectin was elevated during the healing period. Conclusion : We found the good bone formation ability of hyaluronic acid in distraction osteogenesis through the immunohistochemistry and RTPCR analysis to osteocalcin and osteonectin, known as a bone formation marker. The application of hyaluronic acid in distraction osteogenesis is a method to reduce the consolidation period.

Effect of Adhesive Shear Strength of CFRP/Ni-Cr Alloy Under Severe Environmental Condition (가혹 환경이 복합재/Ni-Cr 합금 접착전단강도에 미치는 영향 연구)

  • Cho, Hyeon-Tae;Park, Seong-Min;Kim, Min-Jun;Hoang, Van-Tho;Kim, Hak-Inn;Son, Myung-Sook;Ahn, Jong-Kee;An, Ji-Min;Choi, Jin-Ho;Nam, Young-Woo;Kweon, Jin-Hwe
    • Composites Research
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    • v.33 no.5
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    • pp.275-281
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    • 2020
  • The mechanical property related to lap shear strength of the joint structure between carbon fiber reinforced polymer (CFRP) composite and metal (Ni-Cr Alloy) under varying environmental conditions (temperature and humidity) was studied in order to apply to the aircraft fan blade. Room temperature dry (RTD), elevated temperature wet (ETW), and cold temperature dry (CTD) environmental conditions were chosen for investigation based on the flight conditions of aircraft. Lap shear strength tests were conducted according to ASTM Standard D3528 to evaluate the shear strength. The microstructure characteristic of failure zone was analyzed by SEM images to check the adhesive shear strength with the three environmental conditions. In comparison with shear strength for the RTD condition, the shear strength in the ETW condition was reduced by 72.8% while those for the CTD condition increased by 56.5%. The moisture absorption and high temperature in ETW condition strongly had an affect on mechanical property of adhesive, while cold temperature could enhance the adhesive shear strength due to the higher brittleness.

Characteristics of Electrospun Ag Nanofibers for Transparent Electrodes (전기방사법으로 제조된 Ag 나노섬유의 투명전극 특성)

  • Hyeon, Jae-Young;Choi, Jung-Mi;Park, Youn-Sun;Kang, Jiehun;Sok, Junghyun
    • Journal of the Korean Vacuum Society
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    • v.22 no.3
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    • pp.156-161
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    • 2013
  • We fabricated transparent conductive electrodes with silver (Ag) nanofibers by electrospinning process. Ag nanofibers have high aspect ratio and fused junctions which result in low sheet resistance. Electrospinning is a fast and efficient process to fabricate continuous one-dimensional (1D) nanofibers. Ag/polymer ink were prepared in polymer matrix solution by a sol-gel method. Then, Ag/polymer nanofibers precursors are heated at $200{\sim}500^{\circ}C$ in air for 2 h to eliminate partially the polymers. The topographical features of the Ag nanofibers were characterized by FE-SEM, and the electrical property was analyzed through I-V measurement system. Finally, optical property was measured using UV/VIS spectroscopy. The transparent conductive electrodes with Ag nanofibers exhibited a sheet resistance (Rs) of $250{\Omega}/sq$ at a transparency (T) of 83%. Transparent conductive films, contain the Ag nanofibers as conductive materials, have good electrical, optical, and mechanical properties. Therefore, it is expected to be useful for the application of flexible display in the future.

The Fractural-Mechanical Properties and Durability of Lightweight Concrete Using the Synthetic Lightweight Aggregate (합성경량골재(SLA)를 사용한 경량콘크리트의 파괴, 역학적 특성 및 내구성)

  • Jo Byung-Wan;Park Seung-Kook;Park Jong-Bin;Daniel C. Jansen
    • Journal of the Korea Concrete Institute
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    • v.17 no.1 s.85
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    • pp.19-25
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    • 2005
  • Recycling of waste materials in the construction Industry is a useful method that can cope with an environment restriction of every country. In this study, synthetic lightweight aggregates are manufactured with recycled plastic and fly ash with 12 percent carbon. Nominal maximum-size aggregates of 9.5 mm were produced with fly ash contents of 0, 35, and $80\%$ by the total mass of the aggregate. An expanded clay lightweight aggregate and a normal-weight aggregate were used as comparison. Gradation, density, and absorption capacity are reported for the aggregates. Five batches of concrete were made with the different coarse aggregate types. Mechanical properties of the concrete were determined including density, compressive strength, elastic modulus, splitting tensile strength, fracture toughness, and fracture energy. Salt-scaling resistance, a concrete durability property, was also examined. Compressive and tensile strengths were lower for the synthetic aggregates; however, comparable fracture properties were obtained. Relatively low compressive modulus of elasticity was found for concretes with the synthetic lightweight aggregate, although high ductility was also obtained. As nv ash content of the synthetic lightweight aggregate increased, all properties of the concrete were improved. Excellent salt-scaling resistance was obtained with the synthetic lightweight aggregate containing 80 percent fly ash.

Analysis on the Impact of Composite by Using FEM (유한요소법을 이용한 복합재료의 충격에 관한 해석)

  • Kim, Sung-Soo;Kim, Young-Chun;Hong, Soon-Jik;Kook, Jeong-Han;Kim, Sei-Hwan;Cho, Jae-Ung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.2
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    • pp.542-547
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    • 2013
  • In this study, mechanical property on the composite material of aluminum foam core is investigated by simulation analysis. Impact energies such as 50J, 70J, and 100J are applied to the specimen model. The maximum load occurs at 3.4ms for 50J, 3.2ms for 70J, and 3.2ms for 100J respectively. The striker penetrates the upper face sheet, causing the core to be damaged at 50J test but the lower face sheet remains intact with no damage. It results in occurring with the energy of 52 J. At 70J test, it penetrates the upper face sheet and penetrated the core. And the striker causes the lower face sheet with damage. And it results in occurring with the energy of 65 J. Finally at 100J test, the striker penetrated both the upper face sheet and core and even the lower face sheet. The load becomes maximum at the time when striker penetrates through the upper plate and it rapidly reduced. And then the load increases rapidly when reaching the lower face sheet. And it decreases again. It results in occurring with the energy of 95 J.

A study on electrical response property of photoconductor film for x-ray imaging sensor (X선 영상센서 적용을 위한 광도전체 필름의 전기적 응답특성 연구)

  • Kang, Sang-Sik;Kim, Chan-Wook;Lee, Mi-Hyun;Lee, Kwang-Ok;Moon, Yong-Soo;An, Sung-A;No, Ci-Chul;Park, Ji-Koon
    • Journal of the Korean Society of Radiology
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    • v.3 no.4
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    • pp.29-33
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    • 2009
  • Recently, the compound materials(a-Se, $HgI_2$, PbO, CdTe, $PbI_2$, etc.) that are used in flat panel x-ray imager have been studied for digital x-ray imaging. In this paper, the signal detection properties of $HgI_2$ and a-Se conversion layer, are compared. The thick $HgI_2$ film is fabricated by special particle-in-binder method and the conventional vacuum thermal evaporation is used for a deposition of a-Se film. And an electrical characteristic measurements were investigated about leakage current, signal response property and x-ray sensitivity. From the experimental results show that the $HgI_2$ film has a low operation voltage and high signal generation than that of a-Se.

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Study on the Improving Thermal and Mechanical Properties of Eco-friendly Materials used for Training Ammunition (연습용 탄약 친환경 재료의 내열성 및 기계적 특성 향상에 관한 연구)

  • Kim, Myung-Hyun;Shon, Byoung-Chul;Lee, Young-Tae
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.5
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    • pp.557-562
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    • 2018
  • Unlike live ammunition which has killing power due to the use of high explosives, training ammunition has only the limited explosive effect needed for training purposes, so the risk of accidents is lowered. Because training ammunition is used in large quantities during military drills, the problem of environmental pollution occurs. As most of the waste is left out in the training field, using bio-degradable polymers such as Polylactic Acid (PLA) can provide a solution to these environmental issues. However, bio-degradable polymers such as PLA usually have poor thermal and mechanical properties compared with other general purpose polymers, so they need to be improved before they can be used for military purposes. In this study, Talc is added to the PLA used for the parts of Training Grenades to improve some of their properties and the changes of their thermal and mechanical properties were verified. In the case of the 1 wt.% ~ 5 wt.% PLA/Talc blends, the thermal properties were improved in proportion to the content of Talc, but the best mechanical properties were observed for the 1 wt.% and 3 wt.% PLA/Talc blends.