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Synthesis of TiO2-xNx Using Thermal Plasma and Comparison of Photocatalytic Characteristics (열플라즈마에 의한 TiO2-xNx의 합성 및 광촉매 특성 비교)

  • Kim, Min-Hee;Park, Dong-Wha
    • Applied Chemistry for Engineering
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    • v.19 no.3
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    • pp.270-276
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    • 2008
  • N2 doped TiO2 nano-sized powder was prepared using a DC arc plasma jet and investigated with XRD, BET, SEM, TEM, and photo-catalytic decomposition. Recently the research interest about the nano-sized TiO2 powder has been increased to improve its photo-catalytic activity for the removal of environmental pollutants. Nitrogen gas, reacting gas, and titanium tetrachloride (TiCl4) were used as the raw materials and injected into the plasma reactor to synthesize the N2 doped TiO2 power. The particle size and XRD peaks of the synthesized powder were analyzed as a function of the flow rate of the nitrogen gas. Also, the characteristics of the photo-catalytic decomposition using the prepared powder were studied. For comparing the photo-catalytic decomposition performance of TiO2 powder with that of TiO2 coating, TiO2 thin films were prepared by the spin coating and the pulsed laser deposition. For the results of the acetaldehyde decomposition, the photo-catalytic activity of TiO2xNx powder was higher than that of the pure TiO2 powder in the visible light region. For the methylene blue decomposition, the decomposition efficiency of TiO2 powder was also higher than that of TiO2 film.

Triboelectrostatic Separation of Unburned Carbon from Flyash for Ash Recycling (마찰대전 정전분리기를 이용하여 석탄회에 함유된 미연탄소분 제거에 관한 연구)

  • 이재근;김성찬;손낙원;김두현;오정근
    • Resources Recycling
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    • v.6 no.3
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    • pp.15-21
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    • 1997
  • Flyash from a coal-hed power plan1 is produced approximtcly 3 million tons m 1996 and causes the serious environmentalpmblem due to the disposal in the ash pond. Flyash is an accepted additive in concrete where it adds strength, sulfate ateresistanceand reduced cost, provided acccptablc levcls of unbunrned carbon are mmtmed This papzr describes to investigate thc technicalfeasibility of a dry triboelcctrostatlcp roccss to scparate unburned carbon h m f lyash into economically valuable produck Puliclesof unburned carbon and flyash can be impded positivc and negative surface charzes. rcapeclively. with a copper tniochargcr dueto dirferences in the work function values of thc particles and the tnbacharger. and cm he separated by passing thcm throuph anexternal electic field. A laboratory s d e separation system consists of r sacw feeder for ash supply, a tniocharger, verticalcollecling copper plates, power supplies, a flow meter, and a fan. Separation tests taking into account separahian efficiency and ashrecovery showed that flyash recovery was sh-nngly dependent an thc tnbocharger geomzhy, elect"c ficld strength. flyssh s ~ c a,n dash feeding late. Optimal separation conditions were flyash size less than 125 Fm and electric field shcngrh of 200 kV1m. Ovcr 80%of the flyash with 7% lass on ignition was recovered at wrbon contznts less than 3%bon contznts less than 3%

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Architecture Description Model for Common IT Resource Identification in e-Government Systems (공동활용자원식별을 위한 전자정부 시스템 아키텍처 서술 방안)

  • Shin, Soo-Jeong;Choi, Young-Jin;Jung, Suk-Chun;Seo, Yong-Won
    • The KIPS Transactions:PartD
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    • v.16D no.4
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    • pp.631-642
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    • 2009
  • Although the Korean government is making great effort to prevent the redundancy in IT investment and efficiently allocate the IT budget, actual achievements are quite limited because of the variety of IT resources and different architecture description among organizations and projects. Thus, a standardized description model of the system architecture is strongly needed to identify the common resources and improve the efficiency of IT investment. Therefore, in this paper, we have developed the function-network matrix model which can be used as the basic template for a standard for architecture description of e-Government systems. The function-network matrix model integrates the function tiers and the network areas into a single unified framework, which enables the functionality of each component and the flow of information clearly visible. Moreover, we described the architectures of Korean e-government’s citizen service systems using our model, resulting in clear demonstration of the similarities and differences between different systems, and easy identification of the common resources. Using the architecture description model developed in this research, the consolidation of national IT resources can be promoted, and non-expert IT users can easily recognize the architecture of their systems. In addition, more efficient and systematic IT resource management can be achieved using our model.

An Analysis of Educational Effectiveness of the Kazakhstan Intellectual School International Baccalaureate Diploma Programme(IBDP) (카자흐스탄 영재학교(NIS)의 국제표준 고교교육과정(IBDP)에 대한 교육효과 분석 연구)

  • Aigerim, Belyalova;Park, Sun-Hyung
    • Korean Journal of Comparative Education
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    • v.28 no.3
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    • pp.103-133
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    • 2018
  • The modern world stands on the cusp of massive change in connection with the 4th industrial revolution. Following developed countries, developing countries also try to grow and keep up with the flow. Among them, trough the international cooperation government of Kazakhstan decided to include the International Baccalaureate Diploma Programme(IBDP) into the Nazarbayev Intellectual School(NIS) in April 2013. The goal of this study is to analyze the efficiency of introduction and implementation of the IBDP in the NIS and to consider the possibility of implementing this program in regular schools. To achieve the research goal, was applied the CIPP evaluation model(context - input - process - product) to assess IBDP program systematically. The analysis of empirical data collected due to the results of the international school system implementation, also in this study were used the results of questionnaires and interviews with the students and teachers who took part in the IBDP educational program. The results of the analysis showed that the average satisfaction of teachers and students who participated in IBDP was 3.64 points, however they pointed out the problems with management and organizations of the program, the establishment of a variety of subjects, recruitment of IBDP teachers etc. These measures would help to raise the status of school to the internationalization.

In-situ Stabilization of Heavy Metal Contaminated Farmland Soils Near Abandoned Mine, using Various Stabilizing Agents: Column Test Study (폐광산 주변 중금속 오염 농경지 토양복원을 위한 다양한 첨가제의 안정화 효율 비교: 컬럼시험연구)

  • Lee, Sang-Hoon;Cho, Jung-Hoon
    • Journal of Soil and Groundwater Environment
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    • v.14 no.4
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    • pp.45-53
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    • 2009
  • This study concerned remediation of heavy metal contaminated farmland soils near abandoned mine, using stabilization method, with particular emphasis on the remediating the soils contaminated with multi-elements. In this study, stabilizing heavy metals based on 'In-situ chemical fixation' has been applied to the soil collected from an abandoned mine in Korea, using column test, with various stabilizing agents, including FeSO4, KMnO4, sludge (collected from coal mine drainage treatment pond), zero-valent iron (ZVI), zeolite and CaCO3. Sixty five-days operation of the flow-through columns yield FeSO4+KMnO4 and zeolite are efficient on reducing As leaching from the soil. ZVI and sludge are reducing the leaching of Cu. Although FeSO4+KMnO4 seem to be efficient for most heavy metals, high pH in the initial stage of test enabled high leaching of the heavy metals, whereas fixation of the heavy metals maintain throughout the rest of the test period, with increasing pH up to around 6. Addition of some alkaline agent may inhibit the low pH during the application. The column test was also run as two set: one set incubated with deionized water for 72 hours prior to starting the test, and the other without incubation. The incubated set demonstrated better stabilizing efficiency, indicating the potential optimized operation method.

Measurements and Calculation of Injection Mass Rate of LFG for Intake Injection in Spark Ignition Engines (불꽃점화 엔진의 흡기관 분사를 위한 매립지가스 분사량의 측정 및 계산)

  • Kim, Kyoungsu;Choi, Kyungho;Jeon, Wonil;Kim, Bada;Lee, Daeyup
    • Journal of the Korean Institute of Gas
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    • v.25 no.4
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    • pp.36-42
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    • 2021
  • When the landfill gas generated at the landfill site is released into the atmosphere, methane gas with a high global warming potential is emitted, which adversely affects climate change. When methane contained in landfill gas is used as fuel for internal combustion engines and burned to generate electricity, it is emitted into the atmosphere in the form of carbon dioxide, which can contribute to lowering the global warming potential. Therefore, in order to use the landfill gas as fuel for power generation using an internal combustion engine, it is important to increase the thermal efficiency of the engine. Thus, it is necessary to use a fuel supply system in which gas is injected using an electronically controlled injector at an intake port for each cylinder rather than a fuel supply technology using the conventional mixer technology. In order to use the electronically controlled gas injection method, it is important to accurately measure the mass flow rate according to the conditions of using landfill gas. For this, a study was conducted to measure the injection amount and calculate them in order for the intake port gas injection of landfill gas.

Life Cycle Assessment on Process of Wet Tissue Production (물티슈 제조공정의 전과정 평가)

  • Ahn, Joong Woo
    • Clean Technology
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    • v.24 no.4
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    • pp.269-274
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    • 2018
  • In this study, Life Cycle Assessment (LCA) of wet tissue manufacturing process was performed. The wet tissue manufacturing process consists of preparation of wetting agent (chemical liquid), impregnation of nonwoven fabric into wetting agent and primary and secondary packaging. Data and information were collected on the input and output of the actual process from a certain company and the database of the Korea Ministry of Environment and some foreign countries (when Korean unavailable) were employed to connect the upper and the lower process flow. Based on the above and the potential environmental impacts of the wet tissue manufacturing process were calculated. As a result of the characterization, Ozone Layer Depletion (OD) is 3.46.E-06 kg CFC11, Acidification (AD) is 5.11.E-01 kg SO2, Abiotic Resource Depletion (ARD) is 3.52.E+001yr1, Global Warming (GW) is 1.04.E+02 kg CO2, Eutrophication (EUT) is 2.31.E-02 kg PO43, Photochemical Oxide Creation (POC) was 2.22.E-02 kg C2H4, Human Toxicity (HT) was 1.55.E+00 kg 1,4 DCB and Terrestrial Ecotoxicity (ET) was 5.82.E-04 kg 1,4 DCB. In order to reduce the environmental impact of the manufacturing process, it is necessary to improve the overall process as other general cases and change the raw materials including packaging materials with less environmental impact. Conclusively, the energy consumed in the manufacturing process has emerged as a major issue, and this needs to be reconsidered other options such as alternative energy. Therefore, it is recommended that a process system should be redesigned to improve energy efficiency and to change to an energy source with lower environmental impact. Due to the nature of LCA, the final results of this study can be varied to some extent depending on the type of LCI DB employed and may not represent of all wet tissue manufacturing processes in the current industry.

A Study on the Flow Analysis for KP505 Propeller Open Water Test (유체기기의 표면 금속코팅 적용에 따른 구조건전성 평가)

  • Lee, Han-Seop;Lim, Byung-Chul;Kim, Min-Tae;Lee, Beom-Soon;Park, Sang-Heup
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.8
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    • pp.23-28
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    • 2019
  • The structural integrity of a surface metal coating was evaluated through numerical results to improve the efficiency and reduce the damage caused by cavitation in ships and marine plants. The goal was to ensure structural strength and performance, even if the thickness of the wing is reduced to reduce the weight of the material and surface coating. Analytical methods were used for four models: a non-coating model, one with the same thickness after coating, one with a thickness reduction of 3% after coating, and one with thickness reduction of 5% after coating. With a thickness reduction of 5% after coating, the stress was increased to 12%, and the safety factor was 0.99%, so the structural integrity was insufficient. However, a better material or a thicker coating could allow a sufficient safety factor to be secured. The structural integrity was improved by the coating, and even when the weight was reduced up to 5%, the structural integrity could be sufficiently secured due to the coating effect.

Efficiency of Different Roof Vent Designs on Natural Ventilation of Single-Span Plastic Greenhouse (플라스틱 단동온실의 천창 종류에 따른 자연환기 효과)

  • Rasheed, Adnan;Lee, Jong Won;Kim, Hyeon Tae;Lee, Hyun Woo
    • Journal of Bio-Environment Control
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    • v.28 no.3
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    • pp.225-233
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    • 2019
  • In the summer season, natural ventilation is commonly used to reduce the inside air temperature of greenhouse when it rises above the optimal level. The greenhouse shape, vent design, and position play a critical role in the effectiveness of natural ventilation. In this study, computational fluid dynamics (CFD) was employed to investigate the effect of different roof vent designs along with side vents on the buoyancy-driven natural ventilation. The boussinesq hypothesis was used to simulate the buoyancy effect to the whole computational domain. RNG K-epsilon turbulence model was utilized, and a discrete originates (DO) radiation model was used with solar ray tracing to simulate the effect of solar radiation. The CFD model was validated using the experimentally obtained greenhouse internal temperature, and the experimental and computed results agreed well. Furthermore, this model was adopted to compare the internal greenhouse air temperature and ventilation rate for seven different roof vent designs. The results revealed that the inside-to-outside air temperature differences of the greenhouse varied from 3.2 to 9.6C depending on the different studied roof vent types. Moreover, the ventilation rate was within the range from 0.33 to 0.49min1. Our findings show that the conical type roof ventilation has minimum inside-to-outside air temperature difference of 3.2C and a maximum ventilation rate of 0.49min1.

Comparison and discussion of MODSIM and K-WEAP model considering water supply priority (공급 우선순위를 고려한 MODSIM과 K-WEAP 모형의 비교 및 고찰)

  • Oh, Ji-Hwan;Kim, Yeon-Su;Ryu, Kyong Sik;Jo, Young Sik
    • Journal of Korea Water Resources Association
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    • v.52 no.7
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    • pp.463-473
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    • 2019
  • This study compared the characteristics of the optimization technique and the water supply and demand forecast using K-WEAP (Korea-Water Evaluation and Planning System) model and MODSIM (Modified SIMYLD) model considering wtaer supply priority. Currently, The national water resources plan applied same priority for municipal, industrial and agricultural demand. the K-WEAP model performs the ratio allocation to satisfy the maximum satisfaction rate, whereas the MODSIM model should be applied to the water supply priority of demands. As a result of applying the priority, water shortage decreased by an average of 1,035,000m3 than same prioritized results. It is due to the increase of the return flow rate as the distribution of Municipal and industrial water increases. Comparing the analysis results of K-WEAP and MODSIM applying the priorities, the relative error was within 5.3% and the coefficient of determination (R2) was 0.9999. In addition, if both models provide reasonable water balance analysis results, K-WEAP is superior to GUI convenience for model construction and data processing. However, MODSIM is more effective in simulation time efficiency. It is expected that it will be able to carry out analysis according to various scenarios using the model.