• Nuclear Engineering and Technology
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• 제44권1호
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• pp.21-32
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• 2012

Fluorinated compounds mainly used in the semiconductor industry are potent greenhouse gases. Recently, thermal plasma gas scrubbers have been gradually replacing conventional burn-wet type gas scrubbers which are based on the combustion of fossil fuels because high conversion efficiency and control of byproduct generation are achievable in chemically reactive high temperature thermal plasma. Chemical equilibrium composition at high temperature and numerical analysis on a complex thermal flow in the thermal plasma decomposition system are used to predict the process of thermal decomposition of fluorinated gas. In order to increase economic feasibility of the thermal plasma decomposition process, increase of thermal efficiency of the plasma torch and enhancement of gas mixing between the thermal plasma jet and waste gas are discussed. In addition, noble thermal plasma systems to be applied in the thermal plasma gas treatment are introduced in the present paper.

• 한국축산시설환경학회지
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• 제13권2호
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• pp.129-138
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• 2007

본 연구에서는 잣송이 부산물을 이용하여 인체와 가축에는 무해한 천연 잣송이 부산물 악취저감제를 제조하고 돈분뇨 퇴비화과정에 적용하여 악취 저감효과와 퇴비화에 미치는 영향을 분석하였다. 잣송이 부산물 악취저감제는 분쇄된 잣송이 부산물, 3종의 미생물(Lactobacillus spp., Alcaligenes spp., Pasteurella spp.) 그리고 무기영양소가 첨가된 당밀수를 혼합하여 수분함량을 55%로 조정한 후 $30^{\circ}C$에서 48시간 배양하여 제조하였다. 실험 처리구는 대조구인 톱밥처리구(T1),톱밥과 3종의 미생물을 혼합한 처리구(T2), 톱밥과 제조된 악취저감제(NDA) 처리구(T3)로 하여 실험실 규모의 반응기 내에서 퇴비화를 진행하면서 실험한 결과 퇴비화 기간 동안 모든 실험구는 최고온도 $55^{\circ}C$ 이상까지 상승하며 병원성 유해미생물들이 사멸되는 퇴비화 적정온도 조건에 부합하였다. 또한 퇴비화 전, 후의 이화학적 성상 변화를 분석한 결과 처리구간 큰 차이가 발견되지 않았으나 제조된 악취저감제를 20%이상 사용시 유기물 분해율이 적어져 퇴비화 과정에서 충분한 온도 상승이 이루어지지 않을 우려가 있을 것으로 판단되었다. 또한 악취저감제 사용 시 퇴비화 과정 중 암모니아 가스 발생에 따른 질소소실이 상대적으로 적어 최종 퇴비물질의 질소함량이 상대적으로 높아짐을 알 수 있었다. 퇴비화 기간 중 암모니아($NH_3$)가스 발생양상을 분석한 결과 황화수소($H_2S$)와 머캅탄($CH_3SH$) 등의 황화합물 가스와는 달리 퇴비화 전 과정을 거쳐 지속적으로 발생함을 알 수 있었다. 퇴비화 반응조에서 발생한 암모니아 가스 농도를 비교할 때 31일 동안 포집된 암모니아의 농도는 T1, T2, T3 각각 12,660 mg/L, 11,598 mg/L, 7,367 mg/L로 잣송이 부산물을 이용하여 제조된 악취저감제를 첨가한 T3에서 암모니아가스의 발생이 확실하게 저감됨을 알 수 있었다. 퇴비화 과정 중 발생하는 머캅탄($CH_3SH$)과 황화수소($H_25$)의 일일발생량과 축적량을 측정한 시험에서 제조된 악취저감제를 첨가한 T3에서는 황화수소 가스와 머캅탄 가스가 크게 감소함을 알 수 있었다. 이러한 결과로 미뤄 잣송이 부산물과 미생물을 혼합하여 제조된 악취저감제의 적량 이용은 퇴비화 과정과 퇴비 품질에 영향을 미치지 않으며 퇴비화 과정 중 발생하는 악취물질을 저감시킬 수 있음을 알 수 있었다.

• 한국환경과학회지
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• 제18권11호
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• pp.1215-1224
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• 2009

This study evaluated the applicability of visible-light-driven N- and S-doped titanium dioxide($TiO_2$) for the control of low-level dimethyl sulfide(DMS) and dimethyl disulfide(DMDS). In addition, a photocatalytic unit(PU)-adsorption hybrid was evaluated in order to examine the removal of DMS and DMDS which exited the PU and a gaseous photocatalytic byproduct($SO_2$) which was generated during the photocatalytic processes. Fourier-Tranform-Infrared(FTIR) spectrum exhibited different surface characteristics among the three-types of catalysts. For the N- and S-doped $TiO_2$ powders, a shift of the absorbance spectrum towards the visible-light region was observed. The absorption edge for both the N- and S-doped $TiO_2$ was shifted to $\lambda$ 720 nm. The N-doped $TiO_2$ was superior to the S-doped $TiO_2$ in regards to DMS degradation. Under low input concentration(IC) conditions(0.039 and 0.027 ppm for DMS and DMDS, respectively), the N-doped $TiO_2$ revealed a high DMS removal efficiency(above 95%), but a gradual decreasing removal efficiency under high IC conditions(7.8 and 5.4 ppm for DMS and DMDS, respectively). Although the hybrid system exhibited a superior characteristic to PU alone regarding the removal efficiencies of both DMS and DMDS, this capability decreased during the course of a photocatalytic process under the high IC conditions. The present study identified the generation of sulfate ion on the catalyst surface and sulfur dioxide(maximum concentrations of 0.0019 and 0.0074 ppm for the photocatalytic processes of DMS and DMDS, respectively) in effluent gas of PU. However, this generation of $TiO_2$ would be an insignificant addition to indoor air quality levels.

• 한국농공학회논문집
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• 제56권6호
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• pp.55-62
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• 2014

Torrefaction is considered as a promising pre-treatment for thermochemical utilization of biomass. Torrefaction temperature and time are the critical operation parameters. In this study, investigated were the effects of reaction temperature and time on product composition of torrefaction. scanning electron microscope (SEM) images and thermo gravimetric analyzer (TGA) results were also compared for the effects of the operating parameters. SEM images showed that the pores were observed at the temperature of $250^{\circ}C$ for 30 minutes. Rapid decreases in weight were observed the temperature between 200 and$400^{\circ}C$. Higher heating value of the torrefied biomass was over 5,000 kcal/kg at the temperature of $250^{\circ}C$ for 45 minutes. Energy density, which is defined as the ratio of the energy yield over the mass yield was 1.36 at the temperature of $250^{\circ}C$ for 45 minutes. The energy density was higher up to 1.6 at the temperature of $280^{\circ}C$, which indicates greater loss in mass. The major components of the gas produced in the torrefaction were $CO_2$ and CO, with traces of methane. The total amount of gas was 31.54 l/kg and the calorific value of the gas was $1,164.4Kcal/Nm^3$ at the temperature of $250^{\circ}C$ for 30 minute reaction time. Based on the results of this study, the temperature of effective torrefaction is about $250^{\circ}C$ for 30 to 45 minutes of reaction time. Considering the heating value, it is desirable to utilize the gas for efficient process of torrefaction.

• 펄프종이기술
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• 제48권3호
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• pp.66-72
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• 2016

The applicability of rice husk fiber as a raw material for eco-friendly pulp mold was evaluated in this study. The higher demand of environmental friendly packaging material resulted in the more interest for the natural fiber based pulp mold. The rice husk which is an abundant agricultural byproduct in Asia could be defiberized by an alkaline digestion process. The changes in the pulp mold making process and the properties of pulp mold by the addition of the rice husk were investigated. The addition of rice husk fiber to the pulp mold made with OCC or UBKP resulted in the increase in drainage at the pulp mold forming process. In case of UBKP pulp mold, the addition of rice husk fiber increased the drying efficiency after pulp mold forming since the structure of pulp mold became more bulkier by the addition of the rice husk fiber. Those results showed the rice husk fiber could be applied to the pulp mold manufacturing as one of the eco-friendly natural fiber resources.

• 한국주거학회논문집
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• 제16권3호
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• pp.89-99
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• 2005

This study aims to give an architectural meaning to the process of change in villages formed to maintain the religious lives. We can draw the following conclusion by reviewing and analyzing primarily the details in relation to the bibliography and actually evaluating and analysing the current status of relevant villages secondly in order to understand the architectural meaning of Catholic village. The architectural Image contained in physical architectural phenomenon displays the change in religious values while the social and cultural characters are responding to the architectural space of Cheonho Village, and this, as a cultural byproduct, is the architectural phenomenon that encompasses the process by which religion takes root in the farming society of Korea that reveals the change in value inherent in the community. The result from study that we conducted via the architectural space of Cheonho Village is interpreted as an architectural phenomenon that encompasses the religion as part of routine lives in a way that is different from the process of becoming in-cultural, and this can be interpreted to have a meaning and character as incultural architecture phenomenon.

• 한국컴퓨터정보학회논문지
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• 제21권4호
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• pp.9-15
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• 2016

Symmetry is everywhere in the world around us from galaxy to microbes. From ancient times symmetry is considered to be a reflection of the harmony of universe. Symmetry is not only a significant clue for human cognitive process, but also useful information for computer vision such as image understanding system. Application areas include face detection and recognition, indexing of image database, image segmentation and detection, analysis of medical images, and so on. The technique used in this paper extracts edges, and the perpendicular bisector of any two edge points is considered to be a candidate axis of symmetry. The coefficients of candidate axis are accumulated in the coefficient space. Then the axis of symmetry is determined to be the line for which the coefficient histogram has maximum value. In this paper, an improved method is proposed that utilizes the directional information of edges, which is a byproduct of the edge detection process. Experiment on 20 test images shows that the proposed method performs 22.7 times faster than the original method. In another test on 5 images with 4% salt-and-pepper noise, the proposed method detects the symmetry successfully, while the original method fails. This result reveals that the proposed method enhances the speed and accuracy of detection process at the same time.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.215-219
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• 2001

Impurities removal from waste carbon black was carried out to produce high-grade carbon black. A lot of hydrophilic carbon black is produced as a byproduct of the hydrogen production process by flame decomposition of water. Due to its impurity content such as sulphur, iron, ash and etc., it can only be used as low-grade carbon or burnt out. High-grade hydrophilic carbon black is 3-5 times more expensive than oil-based carbon black because of its process difficulties and requires pollutant treatment. Hydrophilic carbon is normally used far conductive materials for batteries, pigment for plastics, electric wire covering, additives for rubber, etc.. In these applications, hydrophilic carbon must maintain its high purity. In this study magnetic separation, froth flotation and ultrasonic treatment were employed to remove impurities from the low-grade hydrophilic carbon black. As results, the ash, iron and sulphur content of product decreased to less than 0.01wt.%, 0.0lwt.% and 0.3wt.% respectively, and the surface area of product was about 930 $m^2$/g.

• 공업화학
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• 제29권4호
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• pp.474-478
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• 2018

Thermal decomposition of waste Achyranthes Root (WAR) emitted from its decoction process was investigated using a TG analyzer and a fixed-bed reactor. The WAR had the larger C and fixed carbon content than fresh AR (FAR) due to the extraction of hemicelluloses from FAR during decoction process. Thermogravimetric (TG) analysis results also revealed the elimination of hemicellulose by its decoction. Relatively high contents of the cellulose and lignin made high contents of their typical pyrolyzates, such as acids, ketones, furans, and phenols, in the pyrolysis of WAR using the fixed-bed reactor. The increase of pyrolysis temperature from 400 to $500^{\circ}C$ increased yields of oil and gas due to the more effective cracking efficiency of WAR at a higher temperature. The chemical composition of product oil was also changed by applying the higher pyrolysis temperature, which increased the selectivity to furans and phenols.

• 한국건축시공학회지
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• 제18권2호
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• pp.185-193
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• 2018

In this study, using Granulated Blast Furnace Slag (GBFS), an industrial byproduct, and Phosphogypsum (PG), and Waste Lime (WL) as activator, non-sintering binder (NSB) which does not require a sintering process was produced, and the chemical penetration resistance was evaluated through a seawater resistance experiment. The result of the experiment showed that the inside of NSB mortar saw almost no influence from the ions in seawater due to its dense structure. Also, as it appears that only the surface reacts with ions in seawater while spreading inward is suppressed, the high seawater resistance of NSB could be confirmed.