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Design and performance evaluation of Korean traditional heating system—Ondol: Case study of Nepal
Chu, Won-Shik,Kim, Min-Soo,Lee, Kyung-Tae,Bhandari, Binayak,Lee, Gil-Yong,Yoon, Hae-Sung,Kim, Hyung-Soo,Park, Jae-Il,Bilegt, Erkhes,Lee, Jang-Yeob,Song, Ji-Hyun,Park, Gee-Hoon,Bhandari, Pratibha,Lee, Elsevier 2017 Energy and buildings Vol.138 No.-
<P><B>Abstract</B></P> <P>Poor infrastructure in developing countries, combined with challenging geographical characteristics, is associated with problems of limited access to resources, poor transportation and environmental health issues. In some developing countries, there are no heating systems during the winter season, which causes problems for both people and livestock. The most common heating source is from open fires using biomass from animal and plant residue, which are also used for cooking. Fireplaces are typically located inside the house, which can lead to respiratory health problems because of limited ventilation. Thus, heating systems with proper ventilation are desirable to mitigate health problems and improve living conditions. Here we describe the application of ‘Ondol’, a traditional Korean heating system that was redesigned for improved efficiency, in remote villages in a mountainous region of Nepal. Total 10 models of Ondol were designed and fabricated, and the temperature profile and uniformity were characterized to select the optimal design. The height and type of the ‘Gorae’ were the most important factors in determining the efficiency. The optimal design was provided to local people, who were trained to replicate and build the Ondol on their own. A post-installation survey was carried out to evaluate the effectiveness of the system.</P>
Research Advancement of Green Technologies
Chu, Won-Shik,Chun, Doo-Man,Ahn, Sung-Hoon 한국정밀공학회 2014 International Journal of Precision Engineering and Vol.15 No.6
Recently, green technology has become an attraction to researchers in engineering, manufacturing, material science, chemical engineering, environment science and energy areas. In this paper. Six keywords such as, energy saving, energy consumption, green manufacturing, waste reduction, green products, and sustainable manufacturing which were the research fields discussed in the International Symposium on Green Manufacturing and Applications (ISGMA) 2013 were chosen to see the trend and status of green technologies in research area. In the last two decades, the number of journal articles related to the research area of green technology has significantly increased. Engineering is the most widely discussed research area covering the green technology. Also journals from five major research areas in green technology were analyzed with 5-years H-index and the number of journal articles published in recent 5 years.
Won-Shik Chu,Suk-Yong Jeong,Jitendra Kumar Pandey,Sung-Hoon Ahn,Jae-Hoon Lee,Sang-Cheol Chi 한국정밀공학회 2008 International Journal of Precision Engineering and Vol.9 No.2
The Rapid Prototyping (RP) technology has advanced in many application areas. In this research, two different types, cylinder and scaffold. of implantable Drug Delivery System (DDS) were fabricated using Nano Composite Deposition System (NCDS), one of the RP systems. The anti-cancer drug (5-fluorouracil, 5-FU), biodegradable polymer (PLGA(85:15)), and bio ceramic (Hydroxyapatite, HA) were used to form drug-polymer composite material. Both types of DDS were evaluated in vivo environment for two weeks. For evaluation, the cumulative drug release and shape stability were measured. Test results showed that the scaffold DDS provide higher cumulative drug release and has better stability than cylinder DDS.
Fabrication of micro parts using nano composite deposition system
Chu, Won-Shik,Kim, Sung-Geun,Jung, Woo-Kyun,Kim, Hyung-Jung,Ahn, Sung-Hoon MCB UNIVERSITY PRESS 2007 RAPID PROTOTYPING JOURNAL Vol.13 No.5
<B>Purpose</B> - The purpose of this research, is to develop a nano composite deposition system (NCDS) to fabricate three dimensional functional nano composite parts. <B>Design/methodology/approach</B> - The NCDS is a hybrid system in which material removal process by mechanical micro machining and/or the deposition process is combined. <B>Findings</B> - Hybrid RP technology showed higher precision than those made by casting or deposition process. Tensile strength of the hydroxyapatite-acrylic composite was about four times higher than that of resin-only specimen while MWCNT composite did not show much improvement. <B>Originality/value</B> - The paper illustrates new approaches for rapid prototyping techniques with various materials and high precision.
Rapid Prototyping and Testing of 3D Micro Rockets Using Mechanical Micro Machining
Won-Shik Chu,Chang- II Beak,Sung-Hoon Ahn,Tae-Hwan Cho 대한기계학회 2006 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.20 No.1
The trend of miniaturization has been applied to the research of rockets to develop prototypes of micro rockets. In this paper, the development of a web-integrated prototyping system for three-dimensional micro rockets, and the results of combustion tests are discussed. The body of rocket was made of 6061 aluminum cylinder by lathe process. The three-dimensional micro nozzles were fabricated on the same aluminum by using micro endmills with φ100 ㎛ - φ500 ㎛ diameter. Two types of micro nozzle were fabricated and compared for performance. The total mass of the rockets was 7.32 g and that of propellant (gun powder) was 0.65 g. The thrust-to-weight ratio was between 1.58 and 1.74, and the flight test with 45 degree launch angle from the ground resulted in 46 m - 53 m of horizontal flight distance. In addition, ABS housing for the micro machined rocket was fabricated using Fused Deposition Modeling (FDM). A web-based design, fabrication, and test system for micro nozzles was proposed to integrate the distributed hardware resources. Test data was sent to the designer via the same web server for the faster feedback to the rocket designer.
Won-Hyung Choi,Jong-Phil Chu,Meihua Jiang,Yun-Sik Lee,Bum-Shik Kim,Deog-Gon Kim,Yong-Koo Park 대한기생충학열대의학회 2010 The Korean Journal of Parasitology Vol.48 No.1
We analyzed parasitic diseases diagnosed by tissue biopsy specimens at KyungHee Medical Center (KMC) from 1984 to 2005. The total number of parasite infection cases was 150 (0.07%) out of the total 211,859 biopsy specimens submitted for histopathological examinations. They consisted of 62 cysticercosis, 23 sparganosis, 16 paragonimiasis, 15 amebiasis, 11 anisakiasis, 11 clonorchiasis, 3 ascariasis, 2 scabies, 2 enterobiasis, 2 trichuriasis, 1 leishmaniasis, 1 taeniasis, and 1 thelaziasis. Out of 62 cysticercosis cases, 55 were detected in subcutaneous tissues or the central nerve system. Eighteen out of 23 sparganosis cases were involved in muscular and subcutaneous tissues. In most anisakiasis cases, the involved organ was the stomach. The lung and the pleura were the most common site of paragonimiasis. The incidence of parasitic diseases during the first 5 years (1984-1988) was the highest of all observed periods. After 1989, similar incidences were shown throughout the period. Whereas cysticercosis was diagnosed in 34 cases during 1984-1988, no case has been diagnosed since 2000. In the case of sparganosis, the chronological incidence was almost uniform throughout the period 1984-2005. Paragonimiasis showed a similar tendency to cysticercosis. In gender and age distribution of parasitic diseases, men showed higher incidence rates than females, and the age groups of the 40s or older indicated higher infection frequencies than other age groups. Therefore, these results are a significant report to appear the tendency of human parasitic disease diagnosed by tissue biopsy in association with parasitosis at KMC in Seoul.
Rapid Prototyping and Testing of 3D Micro Rockets Using Mechanical Micro Machining
Chu Won-Shik,Beak Chang-Il,Ahn Sung-Hoon,Cho Tae-Hwan The Korean Society of Mechanical Engineers 2006 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.20 No.1
The trend of miniaturization has been applied to the research of rockets to develop prototypes of micro rockets. In this paper, the development of a web-integrated prototyping system for three-dimensional micro rockets, and the results of combustion tests are discussed. The body of rocket was made of 6061 aluminum cylinder by lathe process. The three-dimensional micro nozzles were fabricated on the same aluminum by using micro endmills with ${\phi}100{\mu}m{sim}{\phi}500{\mu}m$ diameter. Two types of micro nozzle were fabricated and compared for performance. The total mass of the rockets was 7.32 g and that of propellant (gun powder) was 0.65 g. The thrust-to-weight ratio was between 1.58 and 1.74, and the flight test with 45 degree launch angle from the ground resulted in $46\;m{\sim}53\;m$ of horizontal flight distance. In addition, ABS housing for the micro machined rocket was fabricated using Fused Deposition Modeling (FDM). A web-based design, fabrication, and test system for micro nozzles was proposed to integrate the distributed hardware resources. Test data was sent to the designer via the same web server for the faster feedback to the rocket designer.
Chu, Won-Shik,Jeong, Suk-Yong,Pandey, Jitendra Kumar,Ahn, Sung-Hoon,Lee, Jae-Hoon,Chi, Sang-Cheol Korean Society for Precision Engineering 2008 International Journal of Precision Engineering and Vol.9 No.2
The Rapid Prototyping (RP) technology has advanced in many application areas. In this research, two different types, cylinder and scaffold, of implantable Drug Delivery System (DDS) were fabricated using Nano Composite Deposition System (NCDS), one of the RP systems. The anti-cancer drug (5-fluorouracil, 5-FU), biodegradable polymer (PLGA(85: 15)), and bio ceramic (Hydroxyapatite, HA) were used to form drug-polymer composite material. Both types of DDS were evaluated in vivo environment for two weeks. For evaluation, the cumulative drug release and shape stability were measured. Test results showed that the scaffold DDS provide higher cumulative drug release and has better stability than cylinder DDS.