• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.4
• /
• pp.118-124
• /
• 2017

In this study, a numerical simulation was performed using commercial code Fluent(v.17.1). The underground Combined Cycle Power Plant (CCPP) was simplified to analyze the methane gas leakage with the crack size and position. In addition, extensive numerical simulations were carried out for different crack sizes from 10 mm to 20 mm. The crack position is the gas leakage, which is assumed to be near the pipe elbow and the gas turbine. A total of 4 cases were compared and analyzed. To analyze the gas leakage, the concept of the Lower Flammable Limit (LFL) was applied. The leakage distance was defined in the longitudinal direction, and the transverse direction was estimated and quantitatively analyzed. As a result, the leakage distance in the longitudinal direction varies by 52.3 % depending on the crack size at the same crack position. Moreover, the maximum difference was 34.8 % according to the crack position when the crack sizes are identical. As jet flow impacts on the obstacle and changes its direction, the recirculation flows are formed. These results are expected to provide useful data to optimize the location and number of gas detections in confined spaces, such as underground CCPP.

• Journal of Legislation Research
• /
• no.53
• /
• pp.491-524
• /
• 2017

Under the general maritime law, a life salvor has no claim against the person saved, and a pure life salvor has no right to compensation from the owner of the ship or its cargo. This harsh rule, which treats the salvor of life less generously than the salvor of property, has been modified by international conventions, statutes, so that life salvors may expect a reward in most cases. It is, especially, unreasonable that a prerequisite of a salvage award is that at least some of the property must be saved, because life of a person can not be compared to values of goods such as vessels and cargoes. Also it is not understandable that only pure life salvors can not expect a reward for the saving of life from the owners of the property. In the meantime, according to Article 39 of the Korean Maritime Search and Rescue Act (hereunder, KMSARA), any person who has gave assistance and rescued in accordance with a governmental officer's order may get a compensation for their time and labour. The above mentioned compensation which is stemmed from the KMSARA may play a role as a compliment for the lack of enough compensation to a life salvor. This means that even though a life salvor failed to save property, he may expect a minimum compensation from the KMSARA. However, it should be recognized that when a life salvor is entitled to both remuneration for the salvage of life and recourse of expenditures from the KMSARA, the total remuneration shall be paid only if and to the extent that such remuneration is greater than any reward recoverable by the salvor under the Korean Commercial Code and the KMSARA.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2016.05a
• /
• pp.1-1
• /
• 2016

Many of the world's large ecosystems are severely stressed due to population growth, water quality and quantity problems, vulnerability to flood and drought, and the loss of native species and cultural resources. Consequences of climate change further increase uncertainties about the future. These major societal challenges must be addressed through innovations in governance, policy, and ways of implementing management strategies. Science and engineering play a critical role in helping define possible alternative futures that could be achieved and the possible consequences to economic development, quality of life, and sustainability of ecosystem services. Science has advanced rapidly during the past decade with the emergence of science communities coalescing around 'Grand Challenges' and the maturation of how these communities function has resulted in large interdisciplinary research networks. An example is the River Experiment Center of KICT that engages researchers from throughout Korea and the world. This trend has been complemented by major advances in sensor technologies and data synthesis to accelerate knowledge discovery. These factors combine to allow scientific debate to occur in a more open and transparent manner. The availability of information and improved communication of scientific and engineering issues is raising the level of dialogue at the science-policy interface. However, severe challenges persist since scientific discovery does not occur on the same timeframe as management actions, policy decisions or at the pace sometimes expected by elected officials. Common challenges include the need to make decisions in the face of considerable uncertainty, ensuring research results are actionable and preventing science being used by special interests to delay or obsfucate decisions. These challenges are explored in the context of examples from the United States, including the California Bay-Delta system. California transfers water from the wetter northern part of the state to the drier southern part of the state through the Central Valley Project since 1940 and this was supplemented by the State Water Project in 1973. The scale of these activities is remarkable: approximately two thirds of the population of Californians rely on water from the Delta, these waters also irrigate up to 45% of the fruits & vegetables produced in the US, and about 80% of California's commercial fishery species live in or migrate through the Bay-Delta. This Delta region is a global hotspot for biodiversity that provides habitat for over 700 species, but is also a hotspot for the loss of biodiversity with more than 25 species currently listed by the Endangered Species Act. Understanding the decline of the fragile ecosystem of the Bay-Delta system and the potential consequences to economic growth if water transfers are reduced for the environment, the California State Legislature passed landmark legislation in 2009 (CA Water Code SS 85054) that established "Coequal goals of providing a more reliable water supply for California and protecting, restoring, and enhancing the Delta ecosystem". The legislation also stated that "The coequal goals shall be achieved in a manner that protects and enhances the unique cultural, recreational, natural resource, and agricultural values of the Delta as an evolving place." The challenges of integrating policy, management and scientific research will be described through this and other international examples.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.22 no.3
• /
• pp.30-35
• /
• 2021

The present study examined the effects of various guide fin structures and boundary parameters on the thermal performance of heat exchangers used in heat recovery thermoelectric generators. The heat transfer rate and pressure drop of the heat exchangers without fins, with circular fins, with triangular fins, and with combined circular and triangular fins were simulated numerically using ANSYS 19.1 commercial code to confirm the effect of the guide fin structures. The heat transfer rate of the heat exchanger with combined fins was 27.0%, 5.2%, and 1.5% higher than those without fins, with circular fins, and with triangular fins, respectively. The pressure drop characteristic of the heat exchanger with the combined fins was 28.3% higher than that without fins but 9.2% and 10.5% lower than those with circular fins and with triangular fins, respectively. The heat exchanger with combined fins as the optimal model showed the highest heat transfer rate of 5664.9 W and pressure drop of 1454.02 Pa for highest hot gas temperature, maximum flow rates of hot gas and coolant, and lowest coolant temperature.

• International Area Studies Review
• /
• v.12 no.2
• /
• pp.277-295
• /
• 2008

Insurable value agreed by the parties shall be presumed specified at the time of the accident. It is nevertheless provided that where agreed value considerably exceeds certain amount evaluated at the time of insured accident, the amount shall be insurable value. It casts doubt on what constitutes such an excess in valuation in marine insurance. Because of the relatively short periods and less volatile economies, maritime insurance, with the statutory insurance value, has deemed insurable value conclusive. In other ways, the provision of default rule substitutes the amount evaluated at the time of insured accident for statutory insurance value. However, over-valuation of agreed value determined by the comparison of statutory insurance value leads to non sequitur in valued policy. Maritime insurance, in the case of over-valuation of agreed value, construes certain amount evaluated at the time of insured accident as insurable value. Accordingly, beyond the application of statutory insurance value, the amount should be considered for over-valuation of agreed value.

• The Journal of the Acoustical Society of Korea
• /
• v.40 no.6
• /
• pp.649-659
• /
• 2021

Wall absorption treatment effectively reduces reverberation, but requires a large area for a live room and each wall absorption affects speech intelligibility differently. In this study, we try to find the most effective wall for the absorption treatment using the beamforming array microphone in terms of speech intelligibility. The absorption importance factor is defined by using the collision number of reflected sounds on each wall. It allows estimating how much the speech signal will be enhanced by the absorption treatment. A cuboid room with a size of 107 m³ and a reverberation time of 1.1 s is selected for the simulation. When a Helmholtz-type absorption is treated on the wall with the most significant importance factor, the modified clarity for 500 and 1k Hz is improved by 5.1 dB and 4.8 dB respectively, and the speech transmission index is enhanced by 0.06. The difference in results between the proposed method and commercial simulation code is less than a Just-Noticeable Difference (JND). The absorption treatment on the wall with the most significant importance factor shows improvement greater than the wall with the largest area, and its difference is larger than a JND value.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.50 no.12
• /
• pp.829-838
• /
• 2022

This study conducts Hypervelocity Impact(HVI) simulations considering space objects with various shapes and different impact angles. A commercial nonlinear structural dynamics analysis code, LS-DYNA, is used for the present simulation study. The Smoothed Particle Hydrodynamic(SPH) method is applied to represent the impact phenomena with hypervelocity. Mie-Grüneisen Equation of State and Johnson-Cook material model are used to consider nonlinear structural behaviors of metallic materials. The space objects with various shapes are modeled as a sphere, cube, cylinder, and cone, respectively. The space structure is modeled as a thin plate(200 mm×200 mm×2 mm). HVI simulations are conducted when space objects with various shapes with 4.119 km/s collide with the space structures, and the impact phenomena such as a debris cloud are analyzed considering the space objects with various shapes having the same mass at the different impact angles of 0°, 30° and 45° between the space object and space structure. Although space objects have the same kinetic energy, different debris clouds are generated due to different shapes. In addition, it is investigated that the size of the debris cloud is decreased by impact angles.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.56 no.2
• /
• pp.182-187
• /
• 2023

Fifteen samples of dried laver Pyropia tenera were collected from markets and processing plants in Korea for an assessment of their microbial and chemical hazards, in accordance with the Korean food code. The contamination levels of total viable bacteria, coliforms, Escherichia coli, and nine other pathogenic bacteria (Staphylococcus aureus, Salmonella spp., Vibrio parahaemolyticus, Clostridium perfringens, Listeria monocytogenes, Enterohemorrhagic Escherichia coli, Yersinia enterocolitica, Bacillus cereus, and Campylobacter jejuni) were evaluated The concentrations of heavy metals (lead, cadmium, total mercury, and total arsenic) and radioactive isotopes (¹³¹I, and ¹³⁴Cs+¹³⁷Cs) in the laver samples were also determined. The total viable count of bacteria was 2.62±0.80 (1.48-4.45) CFU/g. The contamination levels of lead, cadmium, total mercury, and total arsenic were 0.024±0.005 (0.018-0.035), 0.090±0.038 (0.041-0.146), 0.008±0.005 (0.003-0.018) and 1.315±0.372 (0.814-1.930) mg/kg, respectively. All samples tested negative for significant levels of radioactivity, the nine pathogenic bacteria, coliforms, and E. coli (<1.00 CFU/g). We assume that ensuring the microbiological and chemical safety of dried laver can increase the demand for its exportation. The present study may serve as a basis for microbiological and chemical hazard assessment of dried lavers.

• Korean Journal of Community Nutrition
• /
• v.27 no.6
• /
• pp.455-467
• /
• 2022

Objectives: In this study, we suggest a Korean NOVA food classification that can be applied to food consumption among Korean. Based on this suggestion, the nutritional intake of Korean adults from ultra-processed foods (UPFs) was estimated. Methods: Korean commercial food was categorized based on the NOVA food classification criteria through the Korea Food Code and expert meetings. Then, the nutrient intake status of 6,991 participants in the 2018 National Health and Nutrition Examination Survey was analyzed according to the food processing level. Then, 4,152 adult participants (age 19-65) were divided into quartiles on the basis of their intake of UPFs, and the nutrient intakes from UPFs were compared. Results: Korean NOVA Food Classification defines with priority Group I (Unprocessed/ Minimally processed foods) and Group II (Processed culinary ingredients) foods based on the food cooking or consumption. Then, Group III (Processed foods) and Group IV (UPFs) are classified according to whether the characteristics of the raw materials used are maintained or whether the food was consumed before the 1970s. Our analysis results showed that most of the calories in the diet were consumed by Group I (52.7%), followed by Group IV (29.3%). After categorization of the adult participants into four groups according to their energy consumption from UPFs, we found that the highest consumption group (Q4) was younger and had higher percentage of men than women. The comparative analysis of the consumption of ultra-processed foods by Korean adults revealed that participants of a younger age and men consumed higher energy from UPFs than older participants and women, respectively (P < 0.01). Furthermore, the larger intake of UPFs was associated with an increasing trend for a higher intake of energy, sugar, saturated fat (P for trend < 0.001), total fat (P for trend = 0.021), and sodium (P for trend = 0.005), whereas the intake of carbohydrate, protein, and dietary fiber had a decreasing trend (P for trend < 0.001). Conclusions: With the current increase in the consumption of processed and ultra-processed foods, it is important to carefully consider not only nutrient intake but also the level of food processing.

• Korean Journal of Plant Resources
• /
• v.37 no.4
• /
• pp.423-430
• /
• 2024

Cymbidium (C.) spp. 'Wedding Day' was developed by the National Institute of Horticultural and Herbal Science, Rural Development Administration in 2021. This cultivar was derived from the artificial cross between C. 'Boksam Holiday' and C. 'Persicolor' in 2008. After the crossing, 112 seedlings were obtained through in vitro germination and transferred to the green house. Based on their vegetative and flowering characteristics, two lines were selected through the first selection. To confirm the stability and uniformity of the two lines, the first and second trials were conducted from 2017 to 2021. As a result, the final line with the code 'C0844-29' was selected as 'Wongyuo F1-78'. After evaluating consumer preference, the line was named as 'Wedding Day'. This hybrid is medium sized cultivar with long vase life of cut flowers and more than 11 white flowers per stalk. It has 63.2 cm of erect stalks which are suitable for cut flower. The leaves are 65.8 cm long and located lower than the flowers, providing appropriate shape for viewing the flowers. It starts flowering from late January. It has sufficient proliferation ability to enable mass proliferation for commercial use (Registration No. 9523).