• Composites Research
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• v.33 no.5
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• pp.302-308
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• 2020

We measured the thermal conductivity of composite materials manufactured by the autoclave and vacuum bag only processes and predicted the cure behavior of the external and internal of composite parts with a cure kinetics model. The temperature difference between the external and internal depends on the processes because of the change of thermal conductivity. In the autoclave process, the temperature and cure behavior of the internal were similar to those of the external because of the high thermal conductivity. However, the temperature of the internal of the vacuum bag only process was different from that of the external. The difference can influence the part quality and evacuation of air. Compression tests were performed to find the mechanical property using 0° unidirectional specimens. The composite of the vacuum bag only process was found to have a lower compressive strength than that of the autoclave process.

• 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 (ΔH_total = 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%.

• Composites Research
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• v.32 no.5
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• pp.229-236
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• 2019

In this study, the effects of the additional processing parameters on the mechanical properties of thermoplastic composites fabricated with automated fiber placement (AFP) were evaluated. Annealing and vacuum bag only processes were then performed on the manufactured thermoplastic composites, respectively. For verification, the crystallinity was measured by differential scanning calorimetry (DSC), confirming the variation of semi-crystalline thermoplastic composite according to the process conditions. The void content of thermoplastic composites was evaluated by matrix digestion method while microscopic examination confirmed the porosity distribution. The interlaminar shear strength test was conducted for three different process parameters (VBO, annealing, and no treatment). A comparison of the three tested strengths was made, revealing that the porosity value had larger effect on the mechanical properties of the thermoplastic composite compared to the degree of crystallinity. Additionally, when thermoplastic composite melted up, the pores were continuously removed under vacuum process; the removal of the pores resulted in an increase of the interlaminar shear strength.

• Korean Journal of Food Science and Technology
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• v.29 no.5
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• pp.925-931
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• 1997

An attempt was made in this study to investigate the possibility of processing seasoned and semi-dried horse mackerel (Tracharus japonnicus) and to examine its keeping quality, by analyzing the factors such as water content, pH, volatile basic nitrogen, viable cell count, peroxide value, color value and sensory evaluation. For processing of the seasoned and semi-dried product, optimum conditions of drying temperature and drying time were $20^{\circ}C$ and 4 hr, respectively, under $50{\pm}5%$ of relative humidity and 2 m/sec of air blast speed. The shelf-life of the products, vacuum-packaging method in nylon/polyethylene/linear low density polyethylene $(0.015/0.045/0.04\;{\mu}m)$ film bag, was 42 days during storage at $-3{\pm}0.5^{\circ}C$, while that of unpackaged one was only 28 days.