• Korean Journal of Poultry Science
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• v.46 no.2
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• pp.95-103
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• 2019

This study investigated the effect of traditional medicinal plants on the quality characteristics of Samgyetang breast meat and broth. The traditional medicinal plants used in this study were roots of Panax ginseng, Codonopsis lanceolata, Platycodon grandiflorum, Salvia miltiorrhiza, Adenophora triphylla, and Allium hookeri. There was no significant difference (P>0.05) in the moisture, protein, ash content, water holding capacity, and cooking loss of Samgyetang meat with the addition of traditional medicinal plants. The color values (lightness, redness, and yellowness) of Samgyetang meat and broth were significantly different (P<0.05); the 2-thiobarbituric acid reactive substances and shear force of Samgyetang meat were significantly different (P<0.05); and the pH, turbidity, and viscosity of Samgyetang broth were also significantly different (P<0.05) with the addition of traditional medicinal plants. In the overall acceptability of Samgyetang meat, the addition of S. miltiorrhiza showed the highest score compared to that of other treatments (P<0.05). Thus, the addition of traditional medicinal plants in the production of Samgyetang were found to affect the lipid rancidity beneficially with plant species when compared to Samgyetang with Panax ginseng. In conclusion, with the development of Samgyetang using S. miltiorrhiza, it will be possible to develop products with superior quality characteristics in antioxidant, shear force, and overall acceptability.

• Clean Technology
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• v.28 no.4
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• pp.293-300
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• 2022

The remarkable mechanical, electrical, and thermal properties of graphene have recently sparked tremendous interest in various research fields. One of the most promising methods to produce large quantities of graphene dispersion is liquid-phase exfoliation (LPE) which utilizes ultrasonic waves or shear stresses to exfoliate bulk graphite into graphene flakes that are a few layers thick. Graphene dispersion produced via LPE can be transformed into graphene ink to further boost graphene's applications, but producing high-quality graphene more economically remains a challenge. To overcome this shortcoming, an advanced LPE process should be developed that uses relatively cheap natural graphite as a graphene source. In this study, a flow-LPE process was used to exfoliate natural graphite to produce graphene that was three times cheaper and seven times larger than synthetic graphite. The optimal exfoliation conditions in the flow-LPE process were determined in order to produce high-quality graphene flakes. In addition, the structural and electrical properties of the flakes were characterized. The electrical properties of the exfoliated graphene were investigated by carrying out an ink formulation process to prepare graphene ink suitable for inkjet printing, and fabricating a printed graphene pattern. By utilizing natural graphite, this study offers a potential protocol for graphene production, ink formulation, and printed graphene devices in a more industrial-comparable manner.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.10
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• pp.1367-1375
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• 2010

In this study, optimization of the process parameters of the resistance spot welding of a sheet of aluminum-coated boron alloyed steel, 22MnB5, used in hot stamping has been performed by a Taguchi method to increase the strength of the weld joint. The process parameters selected were current, electrode force, and weld time. The heating temperature and heating time of 22MnB5 are considered to be noise factors. It was known that the variation in the thickness of the intermetallic compound layer between the aluminum-coated layer and the substrate, which influences on the formation of nugget, was generated due to the difference of diffusion reaction according to heating conditions. From the results of spot weld experiment, the optimum weld condition was determined to be when the current, electrode force, and weld time were 8kA, 4kN, and 18 cycles, respectively. The result of a test performed to verify the optimized weld condition showed that the tensile strength of the weld joint was over 32kN, which is considerably higher than the required strength, i.e., 23kN.

• Journal of the Korean Institute of Gas
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• v.16 no.4
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• pp.52-58
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• 2012

Recently, waste gas incineration is increasing due to strong environmental regulatory system in Korea. These incinerating facilities are usually connected with the top of the storage tank through pipeline and incinerate off gas with the flame. Therefore, the flame originated from these facilities is likely to move back into pipeline and might cause an explosion of the storage tank. Accordingly, the purpose of this study is to suggest the preventive measures and the way to improve the safety of these incineration systems through the cause analysis of a major industrial accident occurred in a acrylic acid manufacturing process in Korea. As a result of the study, the preventive measures are suggested as follows. (1) Air or inert gas inflow facilities should be well designed to dilute flammable gases into air or inert gas sufficiently before the blower is restarted in order to prevent the explosion (2) It is needed for the detonation-type flame arresters to be installed on the top of the storage tanks. (3) In case of using the deflagration-type flame arresters, it is necessary to install a rupture disk before the arresters, or blow off the flame outside tanks by connecting the tank top and the incinerator with hood-type pipe. (4) TDR should be installed to be restarted automatically after the momentary power failure.

• Composites Research
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• v.30 no.3
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• pp.169-174
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• 2017

Demand of glass fiber reinforced composites (GFRC) increased with developing aircraft and defense industries using resin transfer molding (RTM) process to produce complex product. In this research, wetting, interfacial, and mechanical properties were evaluated with different Cross-linking Density by Molecular Weight of Hardener. Epoxy resin as matrices was used bisphenol-A type and amine-type hardeners with different molecular weight. Specimens were manufactured via RTM and wetting property of resin and glass fiber (GF) mat was evaluated to viscosity of epoxy and injection time of epoxy matrix. Mechanical property of GFRC was determined via flexural strength whereas interfacial properties were determined by interlaminar shear strength (ILSS) and interfacial shear strength (IFSS). The difference in mechanical property depends upon the fiber weight fraction (wt %) of GFRC by RTM as well as the different Molecular Weight of Hardener.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.2
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• pp.298-302
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• 2008

This study was carried out to evaluate brazing characteristics of the braze joint between superhard alloy particles and carbon steel. Two types of insert metals that made by mechanical alloying process were selected for this study. One is composed of Cu, Zn and Ag(MIM-1) and the other one is composed of Cu, Zn, Ag and Cd.(MIM-2) The chemical compositions of these insert metals were similar to AWS BAg-20 and BAg-2a system. And the commercial insert metals(CIM-1, CIM-2) were also evaluated for the comparative study. The characterization of the insert metals were conducted by wettability tests, shear tensile test and microstructural analyses. The results indicated that wettability tests displayed that MIM-1 and CIM-1 insert metals had the larger wetting angle than MIM-2 and CIM-2 and the wetting angle of the MIM-1 showed higher value than that of CIM-1. However these values are less than $25^{\circ}$ that is recommended for standard value for usual insert metals. The highest value of shear tensile tests was obtained from the brazed joint that made by MIN-1 and the value was $2.29{\times}10^2MPa$. This value is appeared to be higher or same as the commercial insert metals. The microstructures of the inserts metals were composed of Cu-rich proeutectic structure for matrix and Ag-rich eutectic structure. The braze joint between superhard alloy particles and carbon steel produced by the MIM-1(Ag-Cu-Zn) system showed sound joint showing stable microstructures. However there was also some porosities at the interface.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.9
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• pp.517-524
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• 2019

The overdrive hub clutch is attached to a 6-speed automatic transmission to reduce fuel consumption by using the additional power of the engine. This paper proposes a means to minimize the load and roll-over ratio on the punch during the piercing process for the overdrive hub clutch product. Die clearance, shear angle, and friction coefficient, which can affect the load and roll-over ratio of the punch during processing, were set as the design variables. Sensitivity analysis was also conducted to determine the influence of each design variable on the punch load and roll-over ratio. As a result, shear angle, friction coefficient and die clearance were found to be sensitive to load and roll-over ratio. The punch load and roll-over ratio were set as the objective function and the equation of each design variable and objective function was derives using the Response Surface Method. Finally, the optimal value of the design variables was derived using the Response Surface Method. Application of this model to finite element analysis resulted in 22.14% improvement in the roll-over ratio of the punch load and material.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.3
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• pp.297-303
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• 2007

Orimulsion, a bitumen-in-water emulsified fuel, has been used throughout the world as a substitute fuel for heavy oil and coal. Orimulsion has relatively high levels of sulfur, nickel, and vanadium, compared to other fuel oils and coals, and has been the subject of much debate regarding the environmental impacts. In Korea, Y power plant has operated boilers with Orimulsion as a fuel, and they has some drawbacks during the plant operation, such as plume opacity. In this study, we investigated the cause of formation mechanism and factors for the plume opacity by investigating the operation data, and measuring the particle size distribution at EP(Electrostatic Precipitator), FGD(Fuel Gas Desulfurization) and TMS(Telecommunications Management System) units. Resulting data showed the primary particles below 1 ${\mu}m$ formed were regrown by the recombination of $SO_3$ in wet-limestone FGD process, and thus the secondary particles are induced to cause the plume opacity.

• Journal of Adhesion and Interface
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• v.21 no.2
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• pp.65-70
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• 2020

Epoxy adhesive was mainly used to combine different composite materials. Epoxy adhesive was a typical thermosetting resin that can be bonded by changing from a linear structure to a three-dimensional network structure by curing reaction of epoxy and hardener. The curing conditions of epoxy adhesive were different with different types of hardener such as mixing ratio, curing time, and temperature. These curing conditions affected to the adhesive property of epoxy adhesive. In industry, it was difficult to proceed the applying epoxy adhesive and combining two parts immediately. The adhesive property decreased by humidity and pre-curing of epoxy adhesive in waiting time between two processes. In this paper, the glass fiber reinforced composite (GFRC) was combined with epoxy adhesive and adhesion property between epoxy adhesive and GFRCs was evaluated using single lap shear test. The different waiting times and humidity conditions were applied to epoxy adhesive in room temperature and adhesive property decreased as the waiting time increased. In small amount of humidity, the adhesive property increased because a small amount of moisture in the surroundings accelerated the curing reaction. In certain amount of humidity, however, the adhesion property decreased.

• Korean Journal of Food Science and Technology
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• v.31 no.3
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• pp.638-643
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• 1999

In this study we prepared 5 types of nutritional beverage base samples containing various ratios of soy protein isolate (SPI) and sodium caseinate as protein source. The rheological properties of each sample were measured and the results were as followes; Samples changed their rheological properties with the ratio of SPI. Samples represented newtonian property with low ratio of SPI, pseudoplastic property with the increment of SPI, and bingham pseudoplastic property with higher increment of SPI (80% as protein source). In this result we conjectured that the more was the SPI, the more was the formation of progel during heat treatment, which could be the reason of the rheological changes. In the test of the relationship between temperature and apparent viscosity, apparent viscosity of samples decreased along with the increment of temperature. In observing the relationship between time and apparent viscosity, we found sample, containing high ratio of SPI (80%), represented thixotropic property clearly with the hysteresis loop.