• Journal of the Korean earth science society
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• v.36 no.6
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• pp.501-511
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• 2015

This study suggests a method of alleviating global warming by the increase of the Earth surface albedo through Artificial Sea ice Increasing (ASI) over the Available Freezing Areas (AFA). The method is developed based on the fact that the large sea surface area in or near the Arctic and the Antarctic has no ice even though both water and air temperatures are below zero and the artificial sea ice generation is thus available. The mean energy of $0.85Wm^{-2}$, which was suspected of adding to the earth by the global warming effect was calculated to offset at once when the sea ice area about $4.09{\times}10^6km^2$ was additionally increased. In addition, three techniques for producing ice plates on the sea surface (using ships, installation apparatus, and floating matter such as Green Cell Foam) for ASI were proposed. According to the result of simple analysis using the energy balance model, when ASI was maximally operated only for 3 months (September, October, and November) over AFA, it is expected that the annual mean temperature of earth surface would be decreased about $0.11^{\circ}C$ in the following year. On the other hand, in case of generating the artificial sea ice in all four seasons, a risk of triggering snowball earth was detected.

• Nuclear Engineering and Technology
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• v.55 no.5
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• pp.1802-1813
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• 2023

Conjugate heat transfer between liquid metal and solid is a common phenomenon in a liquid-metal-cooled fast reactor's fuel assembly and heat exchanger, dramatically affecting the reactor's safety and economy. Therefore, comprehensively studying the sophisticated conjugate heat transfer in a liquid-metal-cooled fast reactor is profound. However, it has been evidenced that the traditional Simple Gradient Diffusion Hypothesis (SGDH), assuming a constant turbulent Prandtl number (Pr_t,, usually 0.85 - 1.0), is inappropriate in the Computational Fluid Dynamics (CFD) simulations of liquid metal. In recent decades, numerous studies have been performed on the four-equation model, which is expected to improve the precision of liquid metal's CFD simulations but has not been introduced into the conjugate heat transfer calculation between liquid metal and solid. Consequently, a four-equation model, consisting of the Abe k - ε turbulence model and the Manservisi k_𝜃 - ε_𝜃 heat transfer model, is applied to study the conjugate heat transfer concerning liquid metal in the present work. To verify the numerical validity of the four-equation model used in the conjugate heat transfer simulations, we reproduce Johnson's experiments of the liquid lead-bismuth-cooled turbulent pipe flow using the four-equation model and the traditional SGDH model. The simulation results obtained with different models are compared with the available experimental data, revealing that the relative errors of the local Nusselt number and mean heat transfer coefficient obtained with the four-equation model are considerably reduced compared with the SGDH model. Then, the thermal-hydraulic characteristics of liquid metal turbulent pipe flow obtained with the four-equation model are analyzed. Moreover, the impact of the turbulence model used in the four-equation model on overall simulation performance is investigated. At last, the effectiveness of the four-equation model in the CFD simulations of liquid sodium conjugate heat transfer is assessed. This paper mainly proves that it is feasible to use the four-equation model in the study of liquid metal conjugate heat transfer and provides a reference for the research of conjugate heat transfer in a liquid-metal-cooled fast reactor.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.40 no.2
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• pp.203-214
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• 2014

We measured the contact dermatitis-causing substances concentrations in 28 commercial oxidative hair-coloring products. This study was aimed to provide the fundamental data about oxidative hair-coloring products. We selected 10 oxidation dyes (p-phenylenediamine, toluene-2,5-diamine, m-phenylenediamine, nitro-p-phenylenediamine, p-aminophenol, m-aminophenol, o-aminophenol, p-methylaminophenol, N,N'-bis(2-hydroxyethyl)-p-phenylenediamine sulfate, 2-methyl-5-hydroxyethylaminophenol) and 4 heavy metal (nikel; Ni, chromium; Cr, cobalt; Co, copper; Cu) as contact dermatitis-causing substances. To identify 10 oxidation dyes, hexane-2% sodium sulfite was used for the rapid and simple extraction and ultra performance liquid chromatography (UPLC) analysis was used for simultaneous analysis in 12 minutes. 10 oxidative dyes were detected as indicated on the product packaging and each concentration was lower than prescribed upper concentration limit by pharmaceutical manufacturing standards. And we analysed inductively coupled plasma-optical emission spectrophotometer (ICP-OES) for content search of heavy metal after microwave digestion. The heavy metal average concentration in oxidative hair-coloring products was 0.572 ${\mu}g/g$ for Ni, 3.161 ${\mu}g/g$ for Cr, 2.029 ${\mu}g/g$ for Co, 0.420 ${\mu}g/g$ for Cu, respectively. The average of concentration in powder type (henna) was higher than those of other foam and cream type oxidative hair-coloring products as follows; 1.800 ${\mu}g/g$ for Ni, 10.127 ${\mu}g/g$ for Cr, 7.082 ${\mu}g/g$ for Co, 1.451 ${\mu}g/g$ for Cu. Hair coloring products were classified into the six colors - black, dark brown, brown, dark brown, light brown, red brown and analyzed. Brown color had the highest average concentration of Co and the others had the highest average concentration of Cr.

• Journal of Animal Science and Technology
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• v.45 no.5
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• pp.875-884
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• 2003

Operational parameters for struvite crystallization, as a process to recover nitrogen and phosphorus resources from animal wastewater, were studied in this research. Crystallization distinctive of NH$_4$-N and PO$_4$$^{3-}$ in accordance to chemical sources, influent pH, aeration and stirring was examined using 2L of working volume of struvite reactor. Also, to find an effective treatment process combining with electrolysis method, removal characteristics of NH$_4$-N and PO$_4$$^{3-}$ in 6 different processes was tested. As chemical sources for the derivation of struvite formation, MgSO$_4$ and MgCl$_2$ were superior to CaCO$_3$ and CaCl$_2$. From experiment which was conducted to know the effects of aeration and stirring on struvite formation, it was revealed that aeration stimulated the crystallization reaction by inducing faster pH increase. While 90% of P removal was achieved within 1 hour under aeration, 14 hours was consumed under stirring condition. Struvite formation under aeration was affected by influent pH. No crystallization was observed at pH 5 level, but active crystallization reaction was induced over pH 6.0. 95% of P removal by struvite formation at pH 6, 7 and 9 was achieved within 3h, 2h and 10 min., respectively. However, over pH 10, operational problem due to excessive foam formation occurred, and blunting of crystallization reaction was observed at pH 11. When consider the pH range of animal wastewater, pH 7 to 9, efficient struvite formation could be achieved by simple aeration, without any chemical usage for pH adjustment. Among tested processes, the treatment process which electrolyzing the supernatant from struvite reactor, providing air to both reactors, showed best pollutant removal efficiencies. In this combined process, the removal efficiencies of NH$_4$-N and PO$_4$$^{3-}$ was 86% and 98%, respectively, and 92.4% of color removal was obtained.

• MISULJARYO - National Museum of Korea Art Journal
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• v.96
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• pp.18-53
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• 2019

The paintings Gyeongpodae Pavilion and Chongseokjeong Pavilion were recently donated to the National Museum of Korea and unveiled to the public for the first time at the 2019 special exhibition "Through the Eyes of Joseon Painters: Real Scenery Landscapes of Korea." These two paintings carry significant implications for understanding Joseon art history. Because the fact that they were components of a folding screen produced after a sightseeing tour of the Gwandong regions in 1557 has led to a broadening of our understanding of sixteenth-century landscape painting. This paper explores the art historical meanings of Gyeongpodae Pavilion and Chongseokjeong Pavilion by examining the contents in the two paintings, dating them, analyzing their stylistic characteristics, and comparing them with other works. The production background of Gyeongpodae Pavilion and Chongseokjeong Pavilion can be found in the colophon of Chongseokjeong Pavilion. According to this writing, Sangsanilro, who is presumed to be Park Chung-gan (?-1601) in this paper, and Hong Yeon(?~?) went sightseeing around Geumgangsan Mountain (or Pungaksan Mountain) and the Gwandong region in the spring of 1557, wrote a travelogue, and after some time produced a folding screen depicting several famous scenic spots that they visited. Hong Yeon, whose courtesy name was Deokwon, passed the special civil examination in 1551 and has a record of being active until 1584. Park Chung-gan, whose pen name was Namae, reported the treason of Jeong Yeo-rip in 1589. In recognition of this meritorious deed, he was promoted to the position of Deputy Minister of the Ministry of Punishments, rewarded with the title of first-grade pyeongnan gongsin(meritorious subject who resolved difficulties), and raised to Lord of Sangsan. Based on the colophon to Chongseokjeong Pavilion, I suggest that the two paintings Gyeongpodae Pavilion and Chongseokjeong Pavilion were painted in the late sixteenth century, more specifically after 1557 when Park Chung-gan and Hong Yeon went on their sightseeing trip and after 1571 when Park, who wrote the colophon, was in his 50s or over. The painting style used in depicting the landscapes corresponds to that of the late sixteenth century. The colophon further states that Gyeongpodae Pavilion and Chongseokjeong Pavilion were two paintings of a folding screen. Chongseokjeong Pavilion with its colophon is thought to have been the final panel of this screen. The composition of Gyeongpodae Pavilion recalls the onesided three-layered composition often used in early Joseon landscape paintings in the style of An Gyeon. However, unlike such landscape paintings in the An Gyeon style, Gyeongpodae Pavilion positions and depicts the scenery in a realistic manner. Moreover, diverse perspectives, including a diagonal bird's-eye perspective and frontal perspective, are employed in Gyeongpodae Pavilion to effectively depict the relations among several natural features and the characteristics of the real scenery around Gyeongpodae Pavilion. The shapes of the mountains and the use of moss dots can be also found in Welcoming an Imperial Edict from China and Chinese Envoys at Uisungwan Lodge painted in 1557 and currently housed in the Kyujanggak Institute for Korean Studies at Seoul National University. Furthermore, the application of "cloud-head" texture strokes as well as the texture strokes with short lines and dots used in paintings in the An Gyeon style are transformed into a sense of realism. Compared to the composition of Gyeongpodae Pavilion, which recalls that of traditional Joseon early landscape painting, the composition of Chongseokjeong Pavilion is remarkably unconventional. Stone pillars lined up in layers with the tallest in the center form a triangle. A sense of space is created by dividing the painting into three planes(foreground, middle-ground, and background) and placing the stone pillars in the foreground, Saseonbong Peaks in the middle-ground, and Saseonjeong Pavilion on the cliff in the background. The Saseonbong Peaks in the center occupy an overwhelming proportion of the picture plane. However, the vertical stone pillars fail to form an organic relation and are segmented and flat. The painter of Chongseokjeong Pavilion had not yet developed a three-dimensional or natural spatial perception. The white lower and dark upper portions of the stone pillars emphasize their loftiness. The textures and cracks of the dense stone pillars were rendered by first applying light ink to the surfaces and then adding fine lines in dark ink. Here, the tip of the brush is pressed at an oblique angle and pulled down vertically, which shows an early stage of the development of axe-cut texture strokes. The contrast of black and white and use of vertical texture strokes signal the forthcoming trend toward the Zhe School painting style. Each and every contour and crack on the stone pillars is unique, which indicates an effort to accentuate their actual characteristics. The birds sitting above the stone pillars, waves, and the foam of breaking waves are all vividly described, not simply in repeated brushstrokes. The configuration of natural features shown in the above-mentioned Gyeongpodae Pavilion and Chongseokjeong Pavilion changes in other later paintings of the two scenic spots. In the Gyeongpodae Pavilion, Jukdo Island is depicted in the foreground, Gyeongpoho Lake in the middle-ground, and Gyeongpodae Pavilion and Odaesan Mountain in the background. This composition differs from the typical configuration of other Gyeongpodae Pavilion paintings from the eighteenth century that place Gyeongpodae Pavilion in the foreground and the sea in the upper section. In Chongseokjeong Pavilion, stone pillars are illustrated using a perspective viewing them from the sea, while other paintings depict them while facing upward toward the sea. These changes resulted from the established patterns of compositions used in Jeong Seon(1676~1759) and Kim Hong-do(1745~ after 1806)'s paintings of Gwandong regions. However, the configuration of the sixteenth-century Gyeongpodae Pavilion, which seemed to have no longer been used, was employed again in late Joseon folk paintings such as Gyeongpodae Pavilion in Gangneung. Famous scenic spots in the Gwandong region were painted from early on. According to historical records, they were created by several painters, including Kim Saeng(711~?) from the Goryeo Dynasty and An Gyeon(act. 15th C.) from the early Joseon period, either on a single scroll or over several panels of a folding screen or several leaves of an album. Although many records mention the production of paintings depicting sites around the Gwandong region, there are no other extant examples from this era beyond the paintings of Gyeongpodae Pavilion and Chongseokjeong Pavilion discussed in this paper. These two paintings are thought to be the earliest works depicting the Gwandong regions thus far. Moreover, they hold art historical significance in that they present information on the tradition of producing folding screens on the Gwandong region. In particular, based on the contents of the colophon written for Chongseokjeong Pavilion, the original folding screen is presumed to have consisted of eight panels. This proves that the convention of painting eight views of Gwangdong had been established by the late sixteenth century. All of the existing works mentioned as examples of sixteenth-century real scenery landscape painting show only partial elements of real scenery landscape painting since they were created as depictions of notable social gatherings or as a documentary painting for practical and/or official purposes. However, a primary objective of the paintings of Gyeongpodae Pavilion and Chongseokjeong Pavilion was to portray the ever-changing and striking nature of this real scenery. Moreover, Park Chung-gan wrote a colophon and added a poem on his admiration of the scenery he witnessed during his trip and ruminated over the true character of nature. Thus, unlike other previously known real-scenery landscape paintings, these two are of great significance as examples of real-scenery landscape paintings produced for the simple appreciation of nature. Gyeongpodae Pavilion and Chongseokjeong Pavilion are noteworthy in that they are the earliest remaining examples of the historical tradition of reflecting a sightseeing trip in painting accompanied by poetry. Furthermore, and most importantly, they broaden the understanding of Korean real-scenery landscape painting by presenting varied forms, compositions, and perspectives from sixteenth-century real-scenery landscape paintings that had formerly been unfound.