• Journal of Environmental Science International
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• v.20 no.10
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• pp.1243-1263
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• 2011

This study was carried out to determine marine environments and phytoplankton community in Deukryang Bay during the period of summer in 1987-2010. Water temperature, salinity, pH and dissolved oxygen were shown in much yearly fluctuations. In August, water temperatures in surface and on bottom were the highest, compared with average surface (24.54$^{\circ}C$) and bottom (22.90$^{\circ}C$) water temperature for 18 years in Deukryang Bay. The main reason is assumed to longer duration of sunshine during the period of August. Although the amount of the rainfall in August was the highest, significant impact of marine environment did not show. Most of dissolved inorganic nitrogen and phosphate in Deukryang were lower concentration during summer and N:P ratio also showed below 18 in Redfield. In particular, extreme increasing of N:P ratio in August was occurred by intensive precipitation. Distribution of phytoplankton community was a consistent occurrence for 18 years. The genus of Chaetoceros, Cosinodisucs and Skeletonema were regarded as the represent diatom, whereas the highest occurrence of genus among dinofagellates was Ceratium. It is thought that the relationship between phytoplankton and nutrient has a strong positive signal, although nutrients persist a little concentration and much fluctuations in marine environments were observed. High availability in phytoplankton is contributed to consistently provide the food organism of shellfish. Consequently, recent decreasing production of shellfish and seed are probably associated with higher temperature during the period of summer. However, higher temperature is also occurred ago and after 2000. On the basis of geography, Deukryang Bay had a small mouth and long channel, which is attributed to decreasing genetic diversity. It is assumed that higher temperature and lower genetic diversity have a extreme impact of larvae and shellfish for reproduction in Deukryang. It is necessary to persistently monitor based on water quality and phytoplankton community.

• Journal of Korean Society of Steel Construction
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• v.28 no.3
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• pp.173-183
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• 2016

Various material characteristics of HSA800 steel were examined and a quantitative criteria about the homogeneity of the strength was proposed. Whether HSA800 steel is satisfied the criteria for homogeneity of the strength or not was also examined. From the test results, the material characteristics of 1/4 point from the extreme fiber in the Z-direction satisfied the KS requirements. The excellent directional properties and impact resistance at low temperatures were also showed from the test results. HSA800 steel satisfied the criteria of homogeneity for the strength of the steel. However, it showed that some structures were banded together at 2/4 point from extreme fiber in the Z-direction from the microscopic tests and attention is needed to be paid in that point.

• Atmosphere
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• v.33 no.1
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• pp.1-20
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• 2023

Holding the longest observation data from April 1904, Busan is one of the essential points to understand the climate variability of the Korean Peninsula without missing data since implementing the modern weather observation of the South Korea. Busan is featured by coastal areas and affected by various climate factors and fluctuations. This study aims to investigate climate variability and changes in climatic variables, extremes, and several weather indexes. The statistically significant change points in daily mean rainfall intensity and temperature were found in 1964 and 1965. Based on the change point detection, 117 years were divided into two periods for daily mean rainfall intensity and temperature, respectively. In the long-term temperature analysis of Busan, the increasing trend of the daily maximum temperature during the period of 1965~2021 was larger than the daily mean temperature and the daily minimum temperature. Applying Ensemble Empirical Mode Decomposition, daily maximum temperature is largely affected by the decadal variability compared to the daily mean and minimum temperature. In addition, the trend of daily precipitation intensity from 1964~2021 shows a value of about 0.50 mm day^-1, suggesting that the rainfall intensity has increased compared to the preceding period. The results in extremes analysis demonstrate that return values of both extreme temperatures and precipitation show higher values in the latter than in the former period, indicating that the intensity of the current extreme phenomenon increases. For Wet-Bulb Globe Temperature (effective humidity), increasing (decreasing) trend is significant in Busan with the second (third)-largest change among four stations.

• Journal of the Korean Institute of Landscape Architecture
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• v.44 no.6
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• pp.84-97
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• 2016

This study was to investigate the user's thermal environments of the children's parks according to pavements and sunscreen types during periods of heat waves. The measurements were conducted at the sand pits, rubber chip pavement, shelters, and green shade ground of the two children's parks located in Jinju, Korea(Chilam: $N\;35^{\circ}11^{\prime}1.4{^{\prime}^{\prim}}$, $E\;128^{\circ}5^{\prime}31.7{^{\prime}^{\prime}}$, elevation 38m, Gaho: $N\;35^{\circ}09^{\prime}56.8{^{\prime}^{\prime}}$, $E\;128^{\circ}6^{\prime}41.1{^{\prime}^{\prime}}$, elevation 24m) over three days during 11-13, August, 2016. The highest ambient air temperatures at the Jinju Meteorological Office during the three measurement days were $35.9{\sim}36.8^{\circ}C$, which corresponded with the extremely hot weather. A series of experiments measured air temperature, relative humidity, wind velocity, black globe temperature, and long-wave and short-wave radiation of the six directions 0.6 m above ground level. The wet bulb globe temperature(WBGT) and the universal thermal climatic index(UTCI) were used to evaluate thermal stress. Surface temperature images of the play equipment were also taken using infrared thermography. Surface temperatures of the play equipment and grounds were used to evaluate burn risk through contact with playground materials. The results showed the following. The maximum air temperatures averaged over 1-hour period for three days were $36.6{\sim}39.4^{\circ}C$. The sun shades reduced those temperatures by up to $2.8^{\circ}C$(green shade) and $1.0^{\circ}C/2.3^{\circ}C$(shelters). The minimum relative humidity values averaged over 1-hour period for three days were 44~50%. The sun shades increased those humidity values by up to 6%(green shade) and 4%/6%(shelters). The risk of heat related illness at the measurement sites of the children's parks were extreme and high in the daytime hours. The maximum WBGT values averaged over a 30-minute period for three days were $31.2{\sim}33.6^{\circ}C$. The sun shades reduced those WBGT values by up to $2.4^{\circ}C$(green shade) and $0.5^{\circ}C/2.1^{\circ}C$(shelters) compared to sandpits, but would not block the risk of heat related illness in the daytime hours. The category of heat stress at the measurement sites of the children's parks were extreme and very strong in the daytime hours. The maximum UTCI values averaged over a 30-minute period for three days were $39.9{\sim}48.1^{\circ}C$. The sun shades reduced those UTCI values by up to $7.8^{\circ}C$(green shade) and $4.1^{\circ}C/8.2^{\circ}C$(shelters) compared to sandpits, but could not lower heat stress category from extreme and very strong to strong and moderate in the daytime hours. According to the burn threshold criteria when skin was in contact with playground materials, the maximum surface temperature of the stainless steels($70.8^{\circ}C$) surpassed three seconds $60^{\circ}C$ threshold for uncoated steel, that of the rubber chip($76.5^{\circ}C$) surpassed five seconds $74^{\circ}C$ threshold for the plastic, that of the plastic slide($68.5^{\circ}C$) and seats($71.0^{\circ}C$) surpassed the one min $60^{\circ}C$ threshold for plastic, respectively. The surface temperatures of shaded play equipment were lower approximately $20^{\circ}C$ than those of play equipment exposed to the sun. Therefore, sun shades can block the risk of burns in daytime hours. Because of the extreme and high risk of heat related illness and extreme and high heat stress at the children's parks during periods of heat waves, parents and administrators must protect children from the use of playgrounds. The risk of burn when contact with play equipments and grounds at the children's parks during periods of heat waves, was very high. The sun shades are essential to block the risk of burn from play equipments and grounds at the children's parks during heat waves.

• Journal of the Korean Society of Radiology
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• v.17 no.7
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• pp.1189-1195
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• 2023

In scenarios involving inspections and verifications of nuclear facilities, ensuring the proper functioning of on-site safeguards equipment is crucial. There have been precedents in Kazakhstan where equipment failed to operate properly due to extremly cold temperatures, and the year-round minimum temperature at North Korea's Punggye-ri nuclear test site is approximately minus 30 degrees Celsius. To ensure the proper functioning of equipment in extreme environments for on-site verification of nuclear activities on the Korean Peninsula, relevant research is necessary. This includes confirming the functionality of equipment used in inspections and verifications, as well as analyzing factors that may disrupt their normal operation. This study aims to conduct a risk analysis for the normal operation of equipment in extreme environments and develop criteria and procedures for environmental-based performance testing. To achieve this, we conducted a risk analysis based on IAEA safeguards, analyzed the utilization of equipment, and performed a risk analysis associated with transportation for on-site verification considering the environmental characteristics of the Korean Peninsula. Furthermore, we provided performance testing criteria and procedures. The research results can be utilized as reference material in the verification and monitoring processes of nuclear activities.

• The Journal of the Convergence on Culture Technology
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• v.1 no.2
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• pp.65-69
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• 2015

Teeth and bones are very resistance to high temperatures and remain recognizable even after prolonged exposures to heat. The effects of heating and burning on teeth have been studied with the aim of discerning a characteristic signature withstanding high temperature, but there have been few studies about a human cremated ash, especially Korea. We are recognizable by elemental composition and can be detected in human cremated ash samples by Scanning electromicroscopy/Energy dispersive X-ray spectrometry analysis(SEM/EDS), cremated, at $800{\sim}900^{\circ}C$ for 1 hour. In this temperature range, different crystals morphologies(spherical, irregular and hexagonal) are observed in SEM. Calcium(Ca) and oxygen(O) increases steadily after cremation in EDS. We suggest that cremated bone have been provided with calcium oxide(CaO) formation at temperature above $900^{\circ}C$. This study offers basic data to assess the structure and elemental compositions of human ash and to determine if these remain identifiable after exposure to extreme temperatures.

• Ocean and Polar Research
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• v.29 no.3
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• pp.263-271
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• 2007

The survival strategies of polar organisms at permanently or extremely cold temperatures and their application to cryobiology were reviewed here. In addition, ongoing studies on psychrophiles also were described. Psychrophiles are extremophiles that can grow and reproduce in cold temperatures, typically at -10 to $20^{\circ}C$. These organisms developed various mechanisms of adaptation to extremely cold environments. Polar organisms cope with these extreme physicochemical conditions using strategies such as avoidance, protection and partnership with other organisms. Understanding on the strategies adopted by polar organisms may provide insight on the physiological process that cells can go through during freezing. Cryopreservation may be able to take advantage of the findings described above. Currently, genomes of many cold-loving organisms have been sequenced and comparative genomics has revealed, at a molecular level, the characteristics of these organisms. The investigation of microorganisms on the polar glaciers may expand our understanding on the origin of life on Earth and other planets.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.1
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• pp.119-124
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• 2017

Objective: The death of animals during transport for slaughter is a major factor indicating the level of welfare in transported animals. The aim of this study was to assess mortality related to the commercial transport of finisher pigs for slaughter in the Czech Republic. Methods: The inspectors of the State Veterinary Administration of the Czech Republic recorded the numbers of finisher pigs transported to processing plants in the Czech Republic for slaughter and the mortality in these pigs in relation to transport in the period from 2009 to 2014. Results: Our results show that the likelihood of death losses in transported pigs increases with increasing transport distance. The transport-related mortality ranged from 0.049% in pigs transported for distances below 50 km to 0.145% in pigs transported for distances exceeding 300 km. The impact of external air temperature on the transport-related mortality found in our study clearly shows that current transport practices fail to ensure the welfare of pigs transported under other than moderate weather. Particularly cold temperatures below $-2^{\circ}C$ were associated with increased death losses in winter transport. Conclusion: Despite a decreasing trend in the mortality of finisher pigs transported for slaughter in Europe, our study suggests that current transport conditions are not efficient at ensuring the welfare of pigs during transport for longer distances and the protection of pigs against the negative impact of extreme ambient temperatures. Further research should focus on developing practical guidelines to improve the welfare of pigs in transit accordingly.

• Journal of Microbiology and Biotechnology
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• v.15 no.1
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• pp.125-130
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• 2005

The growth and phosphatase (phosphomonoesterase) activity of Chroococcidiopsis culture isolated from the cryptoendoliths of the Antarctic were compared with a similar isolate from the Arizona hot desert. Such cyanobacteria living inside rocks share several features with the immobilized cells produced in the laboratory. This study has relevance because the availability of phosphorus is a key factor influencing the growth of these cyanobacteria in nature, in such unique ecological niches as the hot and cold deserts. Phosphatase activity therefore is of particular importance for these organisms if they are to survive without any other source of phosphorus availability. Also, there is paucity of knowledge regarding this aspect of study in cyanobacterial cultures from these extreme environments. The salient feature of this study shows the importance of specific pH and temperatures for growth and phosphatase activity of both cultures, although there were marked differences between the two isolates. The pH and temperature optima for growth and phosphatase activity (PMEase) of Chroococcidiopsis 1 and 2 were 9.5, $240^{\circ}C$ and 8.5, $40^{\circ}C$ respectively. The $K_m and V_max$ values of cultured Chroococcidiopsis 1 showed lower affinity of PMEase for the substrate compared to the enzyme affinity of the same organism when found within the rocks; Chroococcidiopsis 2 and Arizona rocks containing the same alga however showed similar affinity of PMEase for the substrate. An interesting observation was the similarity in response of immobilized Chroococcidiopsis 1 culture and the same organism in the Antarctic rocks to low light and low temperature stimulation of PMEase. This thermal response seems to be related to the ability of the immobilized Antarctic isolate and the rocks to either cryoprotect the PMEase or undergo a change to save the enzyme from becoming nonfunctional under low temperatures. The free cells of Chroococcidiopsis 1 culture however did not show such responses.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.6_2
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• pp.1019-1024
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• 2023

Ceramic materials have excellent material properties such as stability at high temperatures, chemical stability, corrosion resistance, and wear resistance, so they are applicable even in extreme environments of high temperature and pressure. In particular, silicon carbide can be applied in the field of structural ceramics due to its characteristics of high strength, hardness, corrosion resistance, and heat resistance even at high temperatures. In this study, considering the application of silicon carbide materials to next-generation turbines, silicon carbide materials were manufactured using a liquid phase sintering method. When manufacturing liquid phase sintered silicon carbide, sintering additives were added to lower the sintering temperature and densify the material. In Al₂O₃-SiO₂, it was confirmed that the secondary product of the sintering additive was observed as a slightly dark area and was evenly distributed overall, and the fracture surface of Al₂O₃-SiO₂ was in the form of transgranular fracture in which cracks progressed along the crystal plane, and the flexural strength for Al₂O₃-SiO₂ was about 445.6 MPa.