• Journal of Energy Engineering
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• v.11 no.2
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• pp.122-129
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• 2002

The analytical models and algorithm of the SPIKE code, which has been developed by KAERI's KALIMER team to investigate the sodium-water reaction phenomena in the liquid metal reactor, were introduced with its verification calculation results. The sodium water reaction of KALIMER IHTS was evaluated. Early stage of the sodium-water reaction consists of wave and mass transfer regimes. The pressure variations were independent of specific design features in the wave transfer regime. However in the mass transfer regime, the pressure variations were strongly dependent on cover gas volume and rupture disk set pressure. The early stage SWR analysis showed that the KALIMER IHTS with an appropriate cover gas volume and rupture disk set pressure had enough margin to its design pressure.

• Aerospace Engineering and Technology
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• v.9 no.2
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• pp.204-209
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• 2010

The current status of the development of pyrostarters, which play a role as a turbo pump starter in liquid propellant propulsion systems by supplying pressurized gas to power turbines for engine start, has been introduced. Firstly, the development history is briefly summarized, and secondly the current technical status in core parts for the development of pryrostarters such as solid propellants, internal ballistics, rupture discs, and igniters are presented. The current technical achievements could make it feasible to fulfill the development requirements for pyrostarters.

• Journal of Biosystems Engineering
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• v.30 no.4 s.111
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• pp.220-228
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• 2005

This study was conducted to investigate the main factors that contain a rotating velocity ratio between wheel and conveyor belt, a tilt angle of conveyor belt and a rotating velocity of a dick cutter for mechanization of Chinese leek harvest. In the survey on the cultivation of Chinese leek, row spacing of 350 m and cutting height of 10 mm from the ground were set up for field tests. Test equipment was designed to cut, pick up and convey Chinese leek one row by one row. From the results of material tests, pick-up height of conveyor belt was set up at $60\~90m$ from the bottom, and the strain and stress at rupture of Chinese leek was 0.487 m/m and 0.01078 MPa. An elastic coefficient of the rubber (Neoprene) of conveyor belts was 1.1077 under the strain of 0.3 nym. from the results of field tests, the tilt angle of conveyor belt was the range of $25^{\circ}\~30^{\circ}$ under consideration far space of container, the velocity ratio between vehicle and conveying belt was 1 to 2.4~1.7 at 0.1~0.3 m/s of vehicle, and optimum rotating velocity of the disk cutter was 34.8 m/s or more under consideration for soil friction.

• Korean Journal of Materials Research
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• v.24 no.10
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• pp.526-531
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• 2014

Thermal shock resistance property has recently been considered to be one of the most important basic properties, in the same way that the transverse-rupture property is important for sintered hard materials such as ceramics, cemented carbides, and cermets. Attempts were made to evaluate the thermal shock resistance property of 10 vol% TaC added Ti(C,N)-Ni cermets using the infrared radiation heating method. The method uses a thin circular disk that is heated by infrared rays in the central area with a constant heat flux. The technique makes it possible to evaluate the thermal shock strength (Tss) and thermal shock fracture toughness (Tsf) directly from the electric powder charge and the time of fracture, despite the fact that Tss and Tsf consist of the thermal properties of the material tested. Tsf can be measured for a specimen with an edge notch, while Tss cannot be measured for specimens without such a notch. It was thought, however, that Tsf might depend on the radius of curvature of the edge notch. Using the Tsf data, Tss was calculated using a consideration of the stress concentration. The thermal shock resistance property of 10 vol% TaC added Ti(C,N)-Ni cermet increased with increases in the content of nitrogen and Ni. As a result, it was considered that Tss could be applied to an evaluation of the thermal shock resistance of cermets.

• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.5
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• pp.37-45
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• 2017

Extinguishment of a burning solid propellant is difficult, however, dynamic extinction can be induced by fast depressurization in combustion chamber. This paper describes experimental results for the characteristics of extinguishment for composite solid propellants by rapid depressurization. For various composition of solid propellants, depressurization ratio which can induce extinguishment of combustion was obtained using experimental apparatus with rupture disk. Experimental results showed that particle size of oxidizer, mixing ratio of oxidizers with different particle size and contents of metal fuel can affect on the characteristics extinguishement for solid propellant.

• Korean Journal of Plant Tissue Culture
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• v.28 no.6
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• pp.353-357
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• 2001

Transformation of ginseng plants was achieved by biolistic system with cotyledon explants and callus using phosphinothricin acetyl-transferase (PAT) gene resisting to a herbicide of Bialaphos. The binary vector for transformation was constructed with disarmed Ti-plasmid and with double 355 promoter. The introduced NPT II and PAT genes of the transgenic ginseng plants were successfully identified by the PCR, and the survival test on the medium with basta. The transgenic ginseng plants were propagated using repetitive secondary embryogenesis. The transgenic ginseng plantlets had normal structures of roots and shoots, and dormant buds for new year sprouting. We transferred the transgenic plants to greenhouse and observed the continuing growth until a new year.

• Journal of the Korean Institute of Gas
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• v.26 no.6
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• pp.16-23
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• 2022

In this study, characteristics of effect on hydrogen gas was investigated to hydrogen embrittlement by disk and tensile tests. The developed and commercial alloy was fabricated to a plate material made from an alloy ingot. The prepared materials were processed in the form of a disk to measure rupture pressure by hydrogen and helium gas at a rate of 0.1 to 1,000 bar/min. In the hydrogen pre-charged tensile test, a specimen was hydrogenated using an anode charging method, and the yield strength, ultimate tensile strength, elongation, and reduction in area rate were carried by a strain rate test. Also, the microstructure was observed to the fracture surface of the tensile test specimen. As a result, the developed materials satisfied endurable hydrogen embrittlement, and the fractured surface showed a brittleness fracture surface with a depth of several ㎛, but dimple due to ductile fracture could be observed.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.69-72
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• 2011

The ground tests of the dual pulse solid rocket motors(SRM) were performed to prove the performance of the developed dual pulse solid rocket motors. To achieve dual pulse, pulse seperation device(PSD) and independent ignition systems were installed between the 1st pulse motor and the 2nd pulse motor. The three major development goals are as follow. First, the total impulse of the dual pulse SRM must be over 90% of the single SRM which has same envelopment and weight. Second, the ignition of the 2nd pulse motor can be started at any time between 0 and 60 seconds after termination of the 1st pulse motor. Last, the rupture disk of PSD must not be broken at the 1st pulse pressure, but be broken at below 30% of the 2nd pulse operating pressure. The results of the ground tests satisfied the development goals.

• Journal of the Korean Institute of Gas
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• v.17 no.4
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• pp.1-8
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• 2013

The aim of this study is to assess thermal hazards of polystyrene polymerization process by bulk polymerization with accelerating rate calorimeter(ARC) and Multimax reactor system(MM). From this study, we found out that the polymerization process should be operated at reaction temperature of $120^{\circ}C{\sim}130^{\circ}C$. At reaction temperature over $130^{\circ}C$, there was a runaway reaction hazard due to the temperature control failure following a viscosity increase of reaction products. With a cooling failure of a reactor in the early stage of process operation at the reaction temperature ($120^{\circ}C{\sim}130^{\circ}C$), there was a high thermal hazard of burst of a reactor's rupture disk or explosion of a reactor caused by the rapid rise of temperature and pressure to $340^{\circ}C$, 5.3 bar respectively within 30 - 50 minutes.

• Journal of the Korean Institute of Gas
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• v.25 no.2
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• pp.42-51
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• 2021

Facilities that supply specialty gases used in semiconductor manufacturing mainly handles with hazardous and dangerous substances with flammable, toxic, and corrosive properties, and gas cabinets are mainly used as such supply facilities. The effects of the supply facilities were analyzed for each leak through the rupture disk in the gas cabinet and a leak where the leak hole. In this case, gas leaked to the outside depending on the leak area. It is a factor that creates a risk depending on the concentration of the leaked gas. Depending on the risk of leakage, all measures such as safe operation procedures should be reviewed again.