• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.07a
• /
• pp.456-459
• /
• 2003

Polychloroprene(CR) is well known as elastomer commonly utilized in the electrical. It is mainly used for cable jacket and insulator. The irradiation degradation property of polymer materials is very important to prevent unexpected accidents in the Nuclear Power Plant(NPP). The irradiation degradation is caused by the oxidation of polymer materials, and this oxidation is occurred by oxygen radical produced from air. In this study, we evaluate the oxidation properties of CR. CR is irradiated for 200, 400, 600, 1000 kGy radiation dose. The oxidation properties of irradiated CR are investigated by differential scanning calorimetry, dynamic mechanical properties and FT-IR/ATR. Glass transition temperature(Tg), decomposition onset temperature(DOT), loss modulus and mechanical tan $\delta$ values are compared together. The irradiation limit of CR in the NPP, is known for 500 kGy, and this is exactly matched with investigated results.

• Journal of the East Asian Society of Dietary Life
• /
• v.18 no.5
• /
• pp.711-724
• /
• 2008

Guk has been a very important part of the Korean table service for a long time. To study the historical transition of traditional Guk, an analysis of old cookbooks from the Chosun dynasty ($15{\sim}19C$) was conducted based on cooking science. The following is the results of 52 types of Malgunguk from representative old cookbooks such as Sangayorok (1450), Suunjabbang (early 1500s), Eumshikdimibang (1670), Jeungbosallimgyungje (1766), Gyuhabchongsu (1815), Juchan (mid 1800s), Sieuijunsu(late 1800s). The ingredients for Malgunguk contain 30, 35, and 12 types of animal foods, plant foods, and seasonings, respectively. Fish and two to three meats are combined for the main ingredients of Guk, to harmonize the taste. Notably, deer and birds such as pheasants along with parts of beef (short ribs, marrow, Holdaegi) were used. Moreover, it is interesting to note that meat such as pork and chicken were favored to beef, which is contrary to preferences of today. There are only a few Malgunguks that have been passed down before the 16th century those after the 17th century have mostly been reported, but the ingredients have been simplified.

• Fashion & Textile Research Journal
• /
• v.1 no.1
• /
• pp.62-68
• /
• 1999

The study has examined about the origin and change of traditional Japanese dress "Kosode" and classified it according to its ages and also classified its patterns which appeared on the Kosode by its kinds, and divide the patterns with constituent method and expressional method and so, studied and analyzed them with type of patterns according to the change of the times. The result of research were as follows: 1. Subject of patterns that appeared on the Kosode was used with mainly plant pattern, animals pattern, pictorial pattern, artificial pattern, and abstract patterns. 2. Expressional method of this patterns was mostly expressed simply with tie dyeing in ancient times, but it changed complex its expressional method and diversely due to the development of common's culture as time goes on. 3. For the arrangement of its pattern were arranged regularly mostly make demarcate and though they are as if seemed dispersed, but a characteristic that can find regulations in it. 4. Transition of patterns that appeared on the Kosode it developed at the beginning of ancient syouboon, Katasuso pattern and Katamigaori patterns at the samurai's society in the medieval society and developed to Koicho kosode and Kambun kosode in modern times.

• Computational Structural Engineering
• /
• v.9 no.2
• /
• pp.153-161
• /
• 1996

In this paper, theory of fracture mechanics for the pressurized thermal shock is investigated and numerical procedure for the evaluation of the pressure vessel under pressurized thermal shock is developed. For the given material properties, transient history such as temperature and pressure, and postulated flaw, the stress distribution is obtained to calculate stress intensities for a wide range of assumed crack sizes. The stress intensities are compared with the material fracture toughness values corresponding to the chemical compositions and the distribution of the nil ductility transition temperature, to determine the crack growth during the transient. Plant-specific calculations have been performed for several transients and the evaluation results are discussed.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.20 no.6
• /
• pp.562-567
• /
• 2000

Many pressure vessels for power and industrial plant are fabricated from low alloy carbon steels. The inner sides of pressure vessels are commonly weld-cladded with austenitic stainless steels to minimize problems of corrosive attack. Disbonding cracks are often detected at the transition region of welding interlayer, which is serious problem to reliability of pressure vessels. We have developed C-scan system to high speed inspection of overlay weld using DSP(digital signal processor). This system consists of signal processing parts (oscilloscope, pulser/receiver, digitizer, DSP), scanner, program and position controller. The developed system has been applied to a practical ultrasonic testing in overlay weld, and demonstrated high speed with precision

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.20 no.4
• /
• pp.94-105
• /
• 2021

A graphical user interface (GUI) program for steam tracing system selection was developed by using a theoretical model. We derived the model on the basis of the one-dimensional heat transfer theory of conduction and convection through a composite wall. Computational fluid dynamics (CFD) and experiments were performed for validation at steam temperatures of 120.4[℃] and 158.9[℃]. The temperature of a pipe's outer surface obtained through CFD matched well with that predicted by the proposed model for both conditions. By contrast, the experiment results showed a small error at 120.4[℃] and a large error at 158.9[℃] because of the melting of the heat transfer compound and water phase transition. Thus, the steam temperature range of the proposed model is below 120.4[℃].

• Nuclear Engineering and Technology
• /
• v.26 no.2
• /
• pp.265-276
• /
• 1994

Several improvements to the RELAP5/MOD3 reflood model hate been made. These improvement were made to correct deficiencies in the reflood model identified by the assessment of the RELAP5/MOD3 code against FLECHT-SEASET experiments. The improvements consist of modification of reflood wall heat transfer package and adjusting the droplet size in dispersed flow regime. The time smoothing of wall vaporization and level tracking of transition flow are also added to eliminate the pressure spikes and level oscillation during reflood process. Assessment of the improved model against FLECHT-SEASET experimental data and application of LBLOCA analysis for plant shows that the deficiencies have been corrected.

• Geomechanics and Engineering
• /
• v.33 no.4
• /
• pp.401-414
• /
• 2023

Organic clays are ideal habitat for flora and fauna. From a geotechnical perspective, organic clays are soft, weak, variable, heterogeneous and flocculated. Portland cement is a universally common stabiliser. However, some organic acids in soil inhibit full hydration and expose cementation products to rapid dissolution. This paper investigates scopes for use of C₃S cement to enable durable cementation. Prospects of using PP fibre alongside with C₃S cement, scopes for partial replacement of C₃S cement with a plant-based nanosilica and evolution of binders are then investigated. Binding mixtures here mimic the natural functions of rhizoliths, amorphous phases, and calcites. Testing sample population include natural and fibre-reinforced clays, compact mixes of clay - C₃S cement, clay - nanobiosilica, and clay, C₃S cement and nanobiosilica. Benefits and constraints of C₃S cement and fibres for retaining the naturally flocculated structure of organic clays are discussed. Nanobiosilica provides an opportunity to cut the C₃S content, and to transition of highly compressive organic clays into an engineered, open-structured medium with >0.5 MPa compressive strength across the strains spanning from peak to 1.5-times peak.

• Journal of Radiation Protection and Research
• /
• v.47 no.4
• /
• pp.226-236
• /
• 2022

Background: An effective communication strategy for reducing conflicts in South Korea has been designed through the analysis of public perception and communication variables on nuclear power under the conditions of rapidly changing nuclear power policies. Materials and Methods: This study conducted both qualitative research through group discussions based on social psychology and quantitative research through surveys. Results and Discussion: Nuclear power plant (NPP) area residents in favor of nuclear power indicated higher levels of communication, safety perception, and contribution than those against it. NPP area residents trusted the civilian expert groups (18.3%) and local government (17.3%) the most, while metropolitan city residents trusted the Nuclear Safety and Security Commission and the Korea Institute of Nuclear Safety (20.7%) the most. In determining nuclear power policy, both the NPP area residents (18.1%) and metropolitan city residents (17.1%) prioritized safety, health, and the environment. While metropolitan city residents thought that energy security and economic growth (16.4%) were important, NPP area residents thought the current issue of spent fuel rods (14.1%) to be important. Conclusion: It is necessary for the nuclear power industry to have and actively implement communication and conflict resolution strategies based on the patterns obtained in the study results.

• Research in Plant Disease
• /
• v.16 no.2
• /
• pp.176-182
• /
• 2010

Occurrence of plant diseases is dependent on various factors in the agricultural system. Due to recent extensive environmental climate changes, i.e. global warming, agricultural systems such as planting dates and cultivars are being affected. Gradual transition in disease occurrence and incidence in the agricultural fields can also be affected by direct and/or indirect environmental changes. In this study, we evaluated disease occurrence and incidence in soybean plants to investigate whether it could be related with cultivars, planting dates and geographical differences in Korea in 2008. Soybean cultivars including 'Taekwang', 'Pungsan', 'Cheongja 3', 'Saeol', and 'Dawon' were planted in four different dates, May 15, June 1, June 15, and June 30, in two locations, Suwon, and Naju. Soybean diseases such as wild fire and bacterial pustule were mainly found depending on cultivars, planting dates, and areas. Wild fire occurred severely on cv. 'Taekwang' while bacterial blight did on cv. 'Dawon' among tested cultivars. Disease developments of wild fire and bacterial blight generally decreased in delayed planting regardless of cultivars.