• Title, Summary, Keyword: 시차 주사 열량 분석

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Study of Cure Kinetics of Vacuum Bag Only Prepreg Using Differential Scanning Calorimetry (시차주사열량계를 이용한 진공백 성형 프리프레그의 경화 거동 연구)

  • Hyun, Dong Keun;Lee, Byoung Eon;Shin, Do Hoon;Kim, Ji Hoon
    • Composites Research
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    • v.33 no.2
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    • pp.44-49
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    • 2020
  • The cure kinetics of carbon fiber-reinforced prepreg for Vacuum Bag Only(VBO) process was studied by differential scanning calorimetry (DSC). The total heat of reaction (ΔHtotal = 537.1 J/g) was defined by the dynamic scanning test using prepregs and isothermal scanning tests were performed at 130℃~180℃. The test results of isothermal scanning were observed that the heat of reaction was increased as the temperature elevated. The Kratz model was applied to analyze the cure kinetics of resin based on the test results. To verify the simulation model, the degree of cure from panels using different cure cycles were compared with the measurement. The simulation model showed that the error against the experimental value was less than 3.4%.

Aging Analysis of Self Hooting MPPF Capacitor Elements (셀프힐링 금속증착 커패시터 소체의 열화 분석)

  • 곽희로;송길목;김영찬
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.17 no.3
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    • pp.73-79
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    • 2003
  • This paper describes the characteristics of capacitor elements at self healing. Self healing events were forced to be created by the over-rated voltage of the capacitor elements. The self healing site was photographed by the Scanning Electron Microscope and the by-products of self healing were analyzed by the Energy Dispersive X-ray Spectrometer. Also the self healing site was analyzed by the Differential Scanning Calorimeter and the Fourier Transform Infrared Spectrometer. As a result, the main component of by-products due to the hum cut at self healing was carbon. The Fourier Transform Infrared analysis result of the self-healing specimen was similar to that of the virgin specimen, however, different from that of the specimen thermally treated at 500$^{\circ}C$. It was observed that heat flow peaks of virgin specimen were different from self-healing specimen by the Differential Scanning Calorimeter analysis.

An Experimental Study on Measurement of the Reaction Order of a Liquid Fuel with Various Components (혼합 액체연료의 화학반응차수 계측에 관한 실험적 연구)

  • Choi, Hyo-Hyun;Lim, Jun-Seok;Kim, Chul-Jin;Sohn, Chae-Hoon
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • pp.421-424
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    • 2011
  • Thermal Analyses are conducted to measure various factors of a liquid fuel required for numerical analysis. Thermal Analyses are divided into two different methods of TGA (Thermo Gravimetric Analysis) and DSC (Differential Scanning Calorimetry). Non-isothermal experimental results are analyzed using by TGA. The results are filtered by a Freeman Carroll method. At the same time, chemical parameters of unknown liquid fuel, activation temperature and reaction order are measured to 6128.2 K and 1.4, respectively. Furthermore, the parameters can be obtained by various mathematical methods. It is found that tha parameters depend on the processing method.

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Effects of Annealing Heat Treatment Conditions on Phase Transformation of Nitinol Shape Memory Alloy (어닐링 열처리 조건에 따른 NITINOL형상기억합금의 상변환 특성 연구)

  • Yoon Sung Ho;Yeo Dong Jin
    • Composites Research
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    • v.18 no.2
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    • pp.38-45
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    • 2005
  • Phase transformation behaviors and crystal structures of Nitinol shape memory alloy $(54.5Ni-45.5Tiwt\%)$ are investigated by varying annealing heat treatment conditions through DSC (Differential Scanning Calorimetry) and XRD (X-Ray Diffraction). Annealing heat treatment conditions were considered as heat treated times of 5min, 15min. 30m1n, and 45min, as well as heat treated temperatures of $400^{\circ}C,\;500^{\circ}C,\;525^{\circ}C,\;550^{\circ}C,\;575^{\circ}C,\;600^{\circ}C,\;700^{\circ}C,\;800^{\circ}C,\;and\;900^{\circ}C$ According to the results, annealing heat treatment conditions such as heat treated times and heat treated temperatures were found to affect significantly on phase transformation behaviors and crystal structures of Nitinol shape memory alloy.

Arrhenius Kinetic Constants Analysis of BKNO3 under Accelerated Aging (가속노화에 따른 BKNO3의 아레니우스 동역학 상수 분석)

  • Jang, Seung-gyo;Kim, Jun-hyung;Ryu, Byung-tae;Hwang, Jung-min
    • Journal of the Korean Society of Propulsion Engineers
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    • v.20 no.4
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    • pp.34-39
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    • 2016
  • Arrhenius kinetic constants, the activation energy and the pre-exponential factor, of energetic material $BKNO_3$ are estimated using Differential Scanning Calorimetry (DSC). Different from the conventional way, the activation energy was estimated more precisely through DSC aging trial, and the consumed fraction by heat was calculated by comparing the integration of heat flow. We suggested the condition of accelerated aging test for the energetic material $BKNO_3$ and reconsidered the meaning of the thermal accelerated aging.

Effects of Strain-Induced Crystallization on Mechanical Properties of Elastomeric Composites Containing Carbon Nanotubes and Carbon Black (탄소나노튜브 및 카본블랙 강화 고무복합재료의 변형에 의한 결정화가 기계적 특성에 미치는 영향)

  • Sung, Jong-Hwan;Ryu, Sang-Ryeoul;Lee, Dong-Joo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.35 no.9
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    • pp.999-1005
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    • 2011
  • The effects of strain-induced crystallization (SIC) on the mechanical properties of elastomeric composites as functions of extension ratio (${\lambda}$), multiwalled carbon nanotube (CNT) content, and carbon black (CB) content are investigated. The differential scanning calorimetry (DSC) analysis shows that the degree of crystallinity increases with the increase in the CB and CNT content. As ${\lambda}$ increases, the glass transition temperature (Tg) of the composites increases, and the latent heat of crystallization (LHc) of the composites is maximum at ${\lambda}$=1.5. It is found that the mechanical properties have a linear relation with LHc, depending on the CNT content. According to the TGA (thermogravimetric analysis), the weight loss of the composite matrix is 94.3% and the weight of the composites decreases with the filler content. The ratio of tensile modulus ($E_{comp}/E_{matrix}$) is higher than that of tensile strength (${\sigma}_{comp}/{\sigma}_{matrix}$) because of the CNT orientation inside the elastomeric composites.

Explosion Characteristics of Bituminous Coal Dusts in Cement Manufacturing Process (시멘트 제조공정에서 유연탄 분진의 폭발특성)

  • Kim, Won-Hwai;Lee, Seung-Chul;Seung, Sam-Sun;Kim, Jin-Nam
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.9 no.2
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    • pp.257-263
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    • 2008
  • We have examined explosion characteristics of bituminous coal dusts in cement manufacturing process. In order to find the thermal properties, we investigated weight loss and ignition temperature of coal materials using TGA and DSC. Also specific surface area of dust was investigated. Dust explosion experiments with Hartman's dust explosion apparatus have been conducted by varying concentration and size of coal dust for explosion probability and lower limit explosion concentration. According to the results for thermal properties, there is a little change by dust size. However, the specific surface area of dust is increased by decreasing dust size. The explosion test results show that small size and increasing concentration of dusts make dust explosion easier. And we find that the lower limit explosion concentration of bituminous coal is $0.3mg/cm^3$ and the probability is 100% on $0.9mg/cm^3$ in 170/200 mesh used in cement manufacturing process.

Dehydration Characteristics of Cationic Surfactant-Modified Montmorillonite (양이온성 계면활성제로 표면개질된 몬모릴로나이트의 탈수 특성)

  • Seung Yeop Lee;Soo Jin Kim
    • Journal of the Mineralogical Society of Korea
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    • v.15 no.4
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    • pp.305-314
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    • 2002
  • The dehydration of hexadecyltrimethylammonium (HDTMA)-exchanged montmorillonite has been studied using X-ray diffractometry (XRD) and differential scanning calorimetry (DSC). The dehydration in HDTMA-montmorillonite seems to influence the swelling behavior of the organo-clay during heating. The basal d(001) spacing vs temperature curve of the HDTMA-montmorillonite has one broad swelling edge with a shoulder on the low-temperature side. We believe that the shoulder at $100^{\circ}C$ for the HDTMA-montmorillonite is due to interlayer swelling induced by the initial rearrangement of surfactants, and the second edge at $200^{\circ}C$ is caused by interlayer swelling resulting from the secondary vertical reorientation of alkyl chains. It seems that the dehydration of organo-clay induces a reorientation of the alkyl chains by transition to more vertical position relative to the silicate sheets, allowing instantly greater d-spacing.

Thermal Characteristics for Cross-Linking Polyethylene (가교 폴리 에틸렌 수지의 열적 특성 분석)

  • Song, Woo-Chang;Park, Ha-Yong;Shim, Jae-Sun;Bae, In-Su;Song, Jin-Ho;Park, Young-Jik;Kweon, Myeong-Hyun
    • Proceedings of the KIEE Conference
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    • pp.1130-1131
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    • 2015
  • 팰릿 형태의 XLPE (Cross-Linking Polyethylene)를 Hot Press로 시험편을 제작하여 열분석 데이터 처리장치를 이용하여 시차 주사 열량법 (differential scanning calorimetry, DSC)과 열 중량 분석 (Thermo gravimetric analysis, TGA) 등으로 열적 특성을 분석하였다. 분석 결과, XLPE의 전이온도 피크는 $61^{\circ}C$, 용융온도에 해당하는 피크는 $102^{\circ}C$에서 나타났으며 XLPE의 TG 분석 결과 $470^{\circ}C$ 근처에서 한 번의 급격한 열중량 감소를 보였으며 $800^{\circ}C$까지 측정 후 잔류물은 완전 분해되어 거의 존재하지 않았음을 알 수 있었다.

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Characterization of Layered Double Hydroxides(Mg-Al-$CO_3$ systems) and Rehydration Reaction of Their Calcined Products in Aqueous Chromate Solution (층상이중수산화물(Mg-Al-$CO_3$ 체계)의 물리 · 화학적 특성규명 및 소성된 시료의 크롬산이온 수용액에서 재수화반응)

  • Rhee, Seog Woo;Kang, Mun-Ja;Moon, Hichung
    • Journal of the Korean Chemical Society
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    • v.39 no.8
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    • pp.627-634
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    • 1995
  • Layered double hydroxides ($Mg-Al-CO_3$ systems, LDH), which are hydrotalcite-like anionic clay minerals, having different $Mg^{2+}\;to\;Al^{3+}$ ratio were synthesized by coprecipitation method. The subsequent products were characterized by the following methods; elemental analysis, X-ray powder diffraction, thermal analysis (DSC and TGA), FT-IR and $^{27}$Al-MAS NMR. X-ray powder patterns showed that the products formed were layered structure materials. Two heat absorption peaks were observed around 20 ∼280$^{\circ}C$ (surface water and interlayer water) and 280∼500$^{\circ}C$ (water from lattice hydroxide and carbon dioxide from interlayer carbonate) in DSC diagrams, and they were quantitatively analyzed by TGA diagrams (in case LDH4 16.2% and 28.6% respectively). FT-IR spectra indicate that the interlayer carbonate ions occupied symmetrical sites between two adjacent layers in a parallel direction. $^{27}$Al-MAS NMR spectra show only single resonance (8.6 ppm) of the octahedrally coordinated aluminum similar magnesium. When LDH4 was calcined at 560$^{\circ}C$ for 3 hours in air, its layered structure was destroyed giving a mixed metal oxide. However it readily became rehydrated in aqueous chromate solution to its original structure.

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