• Clean Technology
• /
• v.23 no.2
• /
• pp.205-212
• /
• 2017

We investigated the performance of a jet loop reactor (JLR) with the two-fluid venturi-type swirl nozzle (TVSN) during experiment for ammonia removal by air stripping from a synthetic wastewater, and compared it with that of a JLR with the two-fluid venturi-type conventional nozzle (TVCN), with the variation of pH, liquid circulation rate ($Q_L$), and air flow rate ($Q_G$). Their performance levels were compared based on the ammonia removal efficiency and overall mass transfer coefficient ($K_La$). Investigated parameters in a JLR were pH (10-12), air flow rate ($Q_G=5-20L\;min^{-1}$), and liquid circulation rate ($Q_L=25-35L\;min^{-1}$). Throughout the experiment, the ammonia removal efficiency and $K_La$ in a JLR with TVSN was higher than in a JLR with TVCN. This may be due to the enhanced turbulent intensity by swirling flow formed in the JLR with TVSN compared to that with TVCN. Further, we obtained higher $K_La$ when pH, $Q_L$ and $Q_G$ were increased. In particular, $K_La$ was increased more efficiently by increasing $Q_G$ than by increasing pH and $Q_L$.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.23 no.2
• /
• pp.108-113
• /
• 2013

Chalcopyrite material $CuInSe_2$ (CIS) is known to be a very prominent absorber layer for high efficiency thin film solar cells. Current interest in the photovoltaic industry is to identify and develop more suitable materials and processes for the fabrication of efficient and cost-effective solar cells. Various processes have been being tried for making a low cost CIS absorber layer, this study obtained the CIS nanoparticles using commercial powder of 6 mm pieces for low cost CIS absorber layer by high frequency ball milling and cryogenic milling. And the CIS absorber layer was prepared by paste coating using milled-CIS nanoparticles in glove box under inert atmosphere. The chalcopyrite $CuInSe_2$ thin films were successfully made after selenization at the substrate temperature of $550^{\circ}C$ in 30 min, CIS solar cell of Al/ZnO/CdS/CIS/Mo structure prepared under various deposition process such as evaporation, sputtering and chemical vapor deposition respectively. Finally, we achieved CIS nanoparticles solar cell of electric efficient 1.74 % of Voc 29 mV, Jsc 35 $mA/cm^2$ FF 17.2 %. The CIS nanoparticles-based absorber layers were characterized by using EDS, XRD and HRSEM.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.6
• /
• pp.80-85
• /
• 2019

Vanadium dioxide is a well-known metal-insulator phase transition material. Lots of researches of vanadium redox flow batteries have been researched as large scale energy storage system. In this study, vanadium oxide($VO_x$) thin films were applied to cathode for lithium ion battery. The $VO_x$ thin films were deposited on Si substrate($SiO_2$ layer of 300 nm thickness was formed on Si wafer via thermal oxidation process), quartz substrate by RF magnetron sputter system for 60 minutes at $500^{\circ}C$ with different RF powers. The surface morphology of as-deposited $VO_x$ thin films was characterized by field-emission scanning electron microscopy. The crystallographic property was confirmed by Raman spectroscopy. The optical properties were characterized by UV-visible spectrophotometer. The coin cell lithium-ion battery of CR2032 was fabricated with cathode material of $VO_x$ thin films on Cu foil. Electrochemical property of the coin cell was investigated by electrochemical analyzer. As the results, as increased of RF power, grain size of as-deposited $VO_x$ thin films was increased. As-deposited thin films exhibit $VO_2$ phase with RF power of 200 W above. The transmittance of as-deposited $VO_x$ films exhibits different values for different crystalline phase. The cyclic performance of $VO_x$ films exhibits higher values for large surface area and mixed crystalline phase.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.17 no.3
• /
• pp.279-298
• /
• 2019

This study comprehensively addresses recent progress at KAERI in waste treatment technology to cope with waste produced by pyroprocessing, which is used to effectively manage spent fuel. The goal of pyroprocessing waste treatment is to reduce final waste volume, fabricate durable waste forms suitable for disposal, and ensure safe packaging and storage. KAERI employs grouping of fission products recovered from process streams and immobilizes them in separate waste forms, resulting in product recycling and waste volume minimization. Novel aspects of KAERI approach include high temperature treatment of spent oxide fuel for the fabrication of feed materials for the oxide reduction process, and fission product concentration or separation from LiCl or LiCl-KCl salt streams for salt recycling and higher fission-product loading in the final waste form. Based on laboratory-scale tests, an engineering-scale process test is in progress to obtain information on the performance of scale-up processes at KAERI.

• Journal of the Daesoon Academy of Sciences
• /
• v.32
• /
• pp.109-136
• /
• 2019

The purpose of this study is to look at the concept of Gaebyeok as used by Kang Jeungsan (姜甑山) from a civilizational perspective. The combination of East Asian civilization during the period of Korea's port-opening and the subsequent inflow of Western powers with material civilization all at the forefront in the late Joseon Korea, served as the driving force for a new civilizational transition. Unlike the Chuk-sa Party and the Gae-hwa Party, modern Korean religions that emphasized Gaebyeok also responded to Western civilization and suggested a new view of civilization. Kang Jeung-san, resisting discrimination and oppression, presented a civilization built upon mutual beneficence while criticizing Western civilizations which centered on reason. Amid this process of the spread of modern Western civilization, Jeungsan declared the construction of a new civilization to the people who were negatively impacted by various social factions, such as class and gender discrimination, political corruption, exploitation via political corruption, and the inflow of Western powers. Jeungsanist Thought developed criticisms of materialism and human alienation, and this resulted in the claim of Gaebyeok. This was an expression of efforts to build a new civilization that aimed to harmonize, integrate, and thrive. The new civilization envisioned by Jeungsan was that of a society run according to mutual beneficence, and it can be summarized as a 'Civilization of Harmonious Union' that integrates philosophical thought and civilizational models of both East and West. This could also be referred to a 'Civilization of Public-commons and Harmony between Divine Beings and Human Beings (神人公共).' The life of Jeungsan was a life spent in the service of curing the world to save the lives of humanity. Since then, his 'movement of mutual beneficence' as observed in Mugeuk-do and Taegeuk-do were also efforts to build the new civilization envisioned by Jeungsan.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2003.03a
• /
• pp.177-184
• /
• 2003

매립장 내의 설치된 중간 복토층(intermediate cover)은 매립 도중 혹은 매립완료 후 종종 침출수가 하부의 침출수 집배수관으로 이동하는 것을 막아 매립장 내에 일정 침출수위를 형성시킨다. 이렇듯 중간 복토층은 침출수의 원활한 순환을 막아 매립장 바닥에 형성되어야 하는 침출수위가 중간복토층 위에 형성되도록 하는데, 이는 매립장의 구조적 안정성을 깨뜨리고 주변으로 침출수 누출을 유발시키게 된다. 본 연구에서는 이처럼 중간복토층 상부에 형성된 침출수위를 저하시키기 위하여, 폐기물 매립시 중간복토층에 투수성이 뛰어나고 역학적 강도와 화학적 내구성을 갖는 배수파일(Drain Pile)을 설치할 것을 제안하였다. 배수파일은 중간복토층 상부에 형성될 수 있는 침출수를 매립장 바닥으로 배수시키고, 침출수 집배수정으로 이송이 가능하게 만든다. 또한 배수파일은 매립장 내부에 설치됨으로써 폐기물의 자체 강성을 증가시키고, 동시에 매립장의 측방유동을 막아 구조적 안정성을 확보하는 효과도 기대할 수 있다. 실내시험을 통해 배수파일 충진재로서 굴패각의 활용가능성을 확인한 결과, 산업 폐기물인 굴패각이 침출수의 pH를 중화시키고 유해물질인 NH$_{4}$$^{+}$를 제거하는데 효과적임을 확인할 수 있었다. 한편, 실제현장의 침출수흐름을 모사하기 위해 범용 프로그램(SEEP/W)을 이용하여 매립지 내에서 배수 파일의 효과를 확인하였다.

• Journal of the Korean Geosynthetics Society
• /
• v.7 no.4
• /
• pp.1-8
• /
• 2008

Soil vapor extraction (SVE) is an effective and cost efficient method of removing volatile organic compounds (VOCs) and petroleum hydrocarbons from unsaturated soils. However, soil vapor extraction becomes ineffective in soils with low gas permeability, for example soils with air permeabilities less than 1 Darcy. The aim of this study is to investigate numerically the performance of a prefabricated vertical drain (PVD) as a SVE well, and the pattern of the induced air flow. A validated numerical model for a single PVD extraction well is developed based on the result of a well-designed laboratory model test. The validity of the simple analytical approach to determine air permeability based on the results of model tests is also discussed.

• Journal of the Korean Society of Groundwater Environment
• /
• v.4 no.3
• /
• pp.116-121
• /
• 1997

Pilot wetland reactor systems to test acid mine drainage treatment efficiencies for metals were designed and operated at the Dalsung mine and surveyed the operating problems. pH and Eh (redox potential) were measured in situ and anayses of Cd, Pb, As, Zn, Cu, Fe, Al and Mn were carried out in the laboratory. Maximum metal removal efficiencies of the reactor containing the rice stalks, the cow manure and limestones were that Cu, Zn, Fe, Cd, Al, Mn and Pb were lowered by 98%, 100%, 99%, 100%, 97%, 61% and 100%, respectively and at that time the pH and Eh of the effluents from the reactor were 6 and about -300 mV. However, the redox potential was raised and removal of metal elements except aluminium was decreased with operation time. It suggests that the reduced condition is very important for the metal removal. During the operation, problems such as scaling in pipes and volume change of the substrate within the reactor occurred, which were preventing the flow of main drainage in pipes and reactor.

• Journal of the Korean GEO-environmental Society
• /
• v.5 no.4
• /
• pp.57-63
• /
• 2004

In general steel sheet piles are used in the containment system, which are vertical barrier systems for waste disposal and landfill purposes, and roads in excavation for temporary structure. This paper presents case study of the use of an interlocking sheet pile for water and containment. Cut-off Z-type sheet pile joints are investigated to determine their permeability from the field test. Four different joint sealing materials are used in field test. The results showed joint permeability is significant time-dependent and joint-dependent. These are explored and conclusions on permeability characteristics of different sealants are noted. A case study gives a design example as well as suggestion on permeability and water tightness can be implemented in using the sheet pile barrier in civil and environment works. From the test results, the effective sealing programs of sheet pile interlocks are suggested.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.20 no.4
• /
• pp.421-428
• /
• 2008

Youngwon channel located in Chinhae city and formed by the Busan New Port Construction Project has been concerned about the water quality degradation problems because of the flow and pollutants stagnation due to its long-narrow shape. In this study, the water quality(hereafter WQ) variation is analysed by using the monthly WQ data measured in Yongwon channel from 2003 to 2007. The analysis shows that the TN and TP concentration in the inside Yongwon channel is definitely worse than the TN and TP concentration in the entrance of the Yongwon channel based on the 95% confidence level. The COD, TN, and TP concentrations in the Yongwon channel are 1.34, 2.08, and 1.80 times larger than that in the entrance of the Yongwon channel, respectively. It has been found that only the TP concentration in SW-26 station has an increasing trend based on the Mann-Kendall test with respect to 95% confidence level. The other stations and the other WQ constituent changes do not have the any significant trends.