• Clean Technology
• /
• v.27 no.3
• /
• pp.255-260
• /
• 2021

A drawback in the CO₂ capture process using an aqueous amine solution is the high energy requirement for the regeneration process. In order to overcome this disadvantage, this study investigated CO₂ capture characteristics using a biphasic absorbent in which isopropanol (IPA) was introduced into an aqueous solution of diethylenetriamine (DETA). When the IPA composition exceeded 20 wt% in 20 wt% DETA aqueous solution, the absorbent phase was liquid-liquid separated into a CO₂-rich phase and a CO₂-lean phase because of the low solubility of the salt formed by the reaction of CO₂ with DETA in isopropanol. When the isopropanol composition in the DETA aqueous solution increased, the phase volume ratio of the CO₂-rich phase to the volume of the CO₂-lean phase increased; and, accordingly, the CO₂ in the CO₂-rich phase was more concentrated. The results of absorbing CO₂ in a packed tower using 20 wt% DETA + IPA + water absorbent confirmed that both the CO₂ absorption capacity and the absorption rate were higher than that of the 20 wt% DETA aqueous solution. When a biphasic absorbent composed of DETA + IPA + water is applied to CO₂ capture, it can be expected to concentrate CO₂ because of phase separation and thereby reduce regeneration energy owing to volume reduction of the CO₂-rich phase.

• Journal of Digital Convergence
• /
• v.17 no.6
• /
• pp.169-175
• /
• 2019

The aim of this study is to examine the relative economic benefits between the septic tank and exclusive sewage pipe line in designing the large building at combined sewer districts. With the case study of Lotte World Tower Building, we analyze a cost-benefit between two alternatives. The research results showed 2 years of payback period, about ￦6.17 billion of NPV, and 1.93 of B/C ratio for installing the exclusive sewage pipe line in comparison with septic tank. This results provide useful guidelines for policy establishment of the septic tank closure and for plausibility of installing exclusive sewage pipe line when constructing a large building. In the future, it will be necessary to consider additional cost-benefit analysis including burden charge borne by causers, the burden of management responsibility with a exclusive sewage pipe line, and the economic benefits of reducing odor.

• Therapeutic Science for Rehabilitation
• /
• v.8 no.1
• /
• pp.73-84
• /
• 2019

Objective: The purpose of this study is to compare the effect of Lee Silverman Voice Treatment-BIG(LSVT-BIG) intervention which consisted of standardized exercise programs and occupation-based activities for people with Parkinson Disease(PD) on motor functions and quality of life Methods: This study applied a one group pretest-posttest design. The experiment was divided into two parts: pre intervention and post intervention period. Before and after LSVT-BIG intervention, Unified Parkinson's Disease Rating Scale(UPDRS), Time up and go(TUG), Parkinson's Disease Questionnaire-39(PDQ-39) were used to measure the participants' motor functions and quality of life. Based on the LSVT-BIG protocol, three participants received 16 one-hour sessions over 4 weeks by a certified occupational therapist. The results were analyzed by using SPSS. Results: There were improvements in UPDRS and TUG. Additionally, PDQ-39 scores decreased in all participants, which means that their quality of life was improved. Conclusions: The study demonstrated positive effects of LSVT-BIG intervention on motor functions and quality of life of patients with PD.

• Korean Journal of Heritage: History & Science
• /
• v.45 no.2
• /
• pp.72-99
• /
• 2012

Cheomseongdae, Korea's so-called "star-gazing tower" located in the former Silla Dynasty capital of Gyeongju, is generally believed to have maintained its original shape since its construction in 647. The stone structure was closely examined and measured by Gyeongju National Museum in 1962 and reexamined by Korean National Research Institute of Cultural Heritage in 2009. This research noted the following structural anomalies of Cheomseongdae. A corner of the top rectangle layer was broken diagonally in a form that can never be attributed to a natural cause. The four metal clamps under the top rectangle layer had been missing. Four grooves, with unknown usage, exist on the sides of the long rectangular stones projected out of the circular body at the second and third circular layers from the top. On the second circular layer from the top, there are three flat stones, less than a half as tall as their surrounding stones. The average height of the third circular layer from the top is only 23.5 cm, while the overall average of the entire 27 circular layers is 29.9cm. This research postulates that all these anomalies are due to prior destructions and improper restorations of the structure. The first destruction and restoration of Cheomsengdae was likely to have occurred before the mid 15th century. The damages might include a pavilion on the top of the structure and a stone with the name of the structure carved in. The Mongolian invasion in the 13th century was a most likely cause. After the restoration, the structure suffered at least another attack. The damages on the top layer and the missing iron clamps were due to the later attack. The grooves and flat stones were to house holding device that affixed certain objects to the outer surface of the circular body. The metal or stone objects might have faced upward at the four corners of Chemseongdae, bridging the gaps between the rectangle layers and circular layers. The current Chemseongdae lost at least the four affixed objects, four holding devices, and one flat stone.

• Journal of the Korean Institute of Rural Architecture
• /
• v.21 no.3
• /
• pp.69-75
• /
• 2019

The purpose of this study is to provide the conservation management direction about cultural landscape of the traditional villages in the area of Huizhou through the importance-performance analysis. The results of the survey on the importance - performance of 261 people who had many visits to various cultural landscapes of Huizhou villages such as Hongchun, Sidichun etc. are as follows. It was appeared that the item of 'good air' is the highest level of importance and satisfaction and is best condition. The item of 'historical conservation' is the high level of importance, but the level of satisfaction is low, so continuous improvement is necessary. The item of 'Old garden conservation' has high satisfaction but low importance, so it needs to improve its importance through subsequent improvement. The item of 'Keeping of old cemetary and old tower' has low importance and satisfaction but it is above average, so continuous maintenance is needed. The items of 'Preservation of stone gate' and 'Preservation of famous man's birth house' all have slightly higher satisfaction and lower importance. Both items are highly satisfied with their importance, so they should avoid excessive efforts and maintain the present status. Satisfaction with the item of 'water environment and water quality' was the lowest, and the problem of the present condition is the most serious, and a major improvement is needed. The importance and satisfaction of 'Commercial development of old villages' was the lowest among all items. This item is causing serious problems and should provide an overall improvement way to drastically improve the importance and satisfaction. Concentration is necessary to improve the environment of the whole villages, to protect the ecological plants and animals in old villages, to transfer and improve the culture of old villages, to maintain sustainability of the villages, and to protect old temple and old rock in old villages. As the level of satisfaction with sustainability is the lowest in the part of 'Concentrate here', there is a great concern about sustainability. Therefore, it is necessary to focus on sustainability and concentrate on sustainable development.

• The Journal of the Convergence on Culture Technology
• /
• v.5 no.1
• /
• pp.227-234
• /
• 2019

Hyochang Park was the royal tomb of the Joseon Dynasty, where were the tombs of Prince Munhyo and his birth mother Ui-bin Seong, king Soonjo's concubine Sook-Ui Park and Youngon princess by a concubine. It was upgraded from Hyochang tomb to Hyochangwon at King Gojong. The Japanese imperialism destroyed Hyochangwon and made it into a park, also moved to Seosamneung in 1944. After returning from Chongqing after liberation, Kimgu made the independence movement tomb in the empty space of Hyochang Park. There were 3 martyr's tomb, provisional government figure tomb. Kimgu himself was buried in Hyochang Park after his death in 1949. During the regime of Rhee Seung-man and Park Jeong-hee, there was a constant attempt to change the identity of Hyochang Park, where independence activists were buried. Hyochang Stadium, Wonhyo buddhist priest's Statue and North Korean Anti-Communist Tower were established. After democratization in 1987, the independence activist tomb of Hyochang Park began to gain meaning again. The 6th Republic succeeded the provisional government in the Constitution, also the national cemetery and independent park of Hyochang Park were attempted but the social consensus could not be achieved. This study focuses on the historical middle layer and symbolism of Hyochang Park and aims to contribute to social consensus on the identity of Hyochang Park by making a storytelling on the theme of 'Independence Road'.

• Wind and Structures
• /
• v.28 no.4
• /
• pp.255-270
• /
• 2019

Aerodynamic configurations of bridge decks have significant effects on the aerostatic torsional divergence and flutter forsuper long-span bridges, which are onset for selection of suitable bridge decksfor those bridges. Based on a cable-stayed bridge with double main spans of 1500 m, considering typical twin-box, stiffening truss and closed-box section, which are the most commonly used form of bridge decks and assumed that the rigidity of those section is completely equivalent, are utilized to investigate the effects of aerodynamic configurations of bridge decks on aerodynamic instability performance comprised of the aerostatic torsional divergence and flutter, by means of wind tunnel tests and numerical calculations, including three-dimensional (3D) multimode flutter analysis and nonlinear aerostatic analysis. Regarding the aerostatic torsional divergence, the results obtained in this study show twin-box section is the best, closed-box section the second-best, and the stiffening truss section the worst. Regarding the flutter, the flutter stability of the twin-box section is far better than that of the stiffening truss and closed-box section. Furthermore, wind-resistance design depends on the torsional divergence for the twin-box and stiffening truss section. However, there are obvious competitive relationships between the aerostatic torsional divergence and flutter for the closed-box section. Flutter occur before aerostatic instability at initial attack angle of $+3^{\circ}$ and $0^{\circ}$, while the aerostatic torsional divergence occur before flutter at initial attack angle of $-3^{\circ}$. The twin-box section is the best in terms of both aerostatic and flutter stability among those bridge decks. Then mechanisms of aerostatic torsional divergence are revealed by tracking the cable forces synchronous with deformation of the bridge decksin the instability process. It was also found that the onset wind velocities of these bridge decks are very similar at attack angle of $-3^{\circ}$. This indicatesthat a stable triangular structure made up of the cable planes, the tower, and the bridge deck greatly improves the aerostatic stability of the structure, while the aerodynamic effects associated with the aerodynamic configurations of the bridge decks have little effects on the aerostatic stability at initial attack angle of $-3^{\circ}$. In addition, instability patterns of the bridge depend on both the initial attack angles and aerodynamic configurations of the bridge decks. This study is helpful in determining bridge decksfor super long-span bridges in future.

• Plant Journal
• /
• v.14 no.4
• /
• pp.39-47
• /
• 2018

In this research, when the output of the standard coal-fired thermal power plant operating continuously at the rated output of 500 MW is changed to operate at 300 to 500 MW, the amount of sulfur oxide produced and the amount of sulfur oxide in the absorption tower of desulfurization equipment and proposed an extra liquid to gas ratio improvement inversely proportional to the output. In order to calibrate the combustion efficiency at low power, the ratio of sulfur oxides relative to the amount of combustion gas is increased as the excess air ratio is increased. When the concentration of sulfur oxide at the inlet of the desulfurization absorber was changed from 300 to 500 ppm along with the output fluctuation. The liquid to gas ratio of limestone slurry and combustion gas was changed from 10.99 to 16.27. Therefore, if the concentration of sulfur oxides with output of 300 MW is x, The following correlation equation is recommended for the minimum required flow rate of slurry for the reduction of surplus energy due to the increase of the liquid weight at low load. $y1[m^3/sec]=0.11x+3.74$

• Economic and Environmental Geology
• /
• v.53 no.6
• /
• pp.655-666
• /
• 2020

This study evaluated the characteristics of arsenic production in groundwater through microbial community analysis of groundwater contaminated with high arsenic in Haman area. Groundwater in Haman area is contaminated with arsenic in the range of 0-757.2 ㎍/L, which represents the highest arsenic contamination concentration reported in Korea as natural groundwater pollution source. Of the total 200 samples, 29 samples (14.5%) showed higher arsenic concentration than that of 10 ㎍/L, which is the standard for drinking water quality, and 8 samples (4%) found in wells with 80-100 m depth were above 50 ㎍/L. In addition, seven wells with arsenic concentration more than 100 ㎍/L located in the northern part of Haman. As a result of microbial community analysis for high arsenic-contaminated groundwater, the microbial community compositions were significantly different between each sample, and Proteobacteria was the most dominant phyla with an average of 61.5%. At the genus level, the Gallinonella genus was predominant with about 12.8% proportion, followed by the Acinetobacter and Methermicoccus genus with about 7.8 and 7.3%, respectively. It is expected that high arsenic groundwater in the study area was caused by a complex reaction of geochemical characteristics and biogeochemical processes. Therefore, it is expected that the constructed information on geochemical characteristics and microbial communities through this study could be used to identify the origin of high arsenic groundwater and the development of its controlling technology.

• Conservation Science in Museum
• /
• v.24
• /
• pp.55-74
• /
• 2020

The Sacred Bell of Great King Seongdeok is required digital precision recording of conservation conditions because of corrosion and partial abrasion of its patterns and inscriptions. Therefore, this study performed digital documentation of the bell using four types of scanning and unmanned aerial vehicle (UAV) photogrammetry technologies, and performed the various shape analyses through image processing. The modeling results of terrestrial laser scanning and UAV photogrammetry were merged and utilized as basic material for monitoring earthquake-induced structural deformation because these techniques can construct mutual spatial relationships between the bell and its tower. Additionally, precision scanning at a resolution four to nine times higher than that of the previous study provided highly valuable information, making it possible to visualize the patterns and inscriptions of the bell. Moreover, they are well-suited as basic data for identifying surface conservation conditions. To actively apply three-dimensional scanning results to the conservation of the original bell, the time and position of any changes in shape need to be established by further scans in the short-term. If no change in shape is detected by short-term monitoring, the monitoring should continue in medium- and long-term intervals.