• Korean Journal of Construction Engineering and Management
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• v.15 no.6
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• pp.83-91
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• 2014

The global community demands the reduction of environmental pollution such as greenhouse gas and carbon dioxide emissions. According to these requirements, the road construction project in the highest energy consuming industry is required the efficient way of reducing environmental pollution emissions. In this study, during the whole life cycle process, an environment impact assessment was performed for the several road construction projects in order to evaluate environmental stress through the road construction process. This study provides a proper process of environment impact assessment for life cycle assessment (LCA) analysis of road construction project, and figures the environmental stress regarding to the major construction materials for the case projects. In addition, this study conducted a sensitivity analysis for the key materials of environmental stress through the quantity analysis of major materials for the 1km section of a road construction. By this sensitivity analysis of total environmental stress change from the different volumes of constructing materials, it would be useful information for the environment impact assessment for the future road construction project.

• International Journal of Highway Engineering
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• v.14 no.3
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• pp.151-162
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• 2012

It is not surprising to hear news about irresistible natural disasters all over the world due to climate change. Korean Government has focused on developing a variety of green technologies to reduce green house gasses, in particular, carbon dioxide. This study suggested 18 technology divisions for achieving green highway technology development in six different sub-sectors considering life-cycle of roadway and surveyed 29 highway and/or transportation professionals of three institutes using AHP(Analytical Hierarchy Process) analysis to construct "Green Highway"and realize carbon emission reductions and energy use efficiency in a road sector in Korea. Expert Choice Software was used to rank 18 technology divisions weighted by two-level choices. Transport Operating Infrastructure Improvement, Roadway Policy Implementation, Green Transportation(such as Pedestrian and Bicycle) were highly ranked by respondents according to results of the AHP modeling. Among the 18 divisions, technology policy for supporting R&D investments from development to commercialization was ranked as the most significant one to be focused. Green Transportation Facility Design/Construction/Operation and Eco-Friendly Roadway Plan were followed as expected since professionals have thought that the planning/design step of the life-cycle is a starting point to reduce carbon dioxide from roads more and more. Additionally, comparing the results with the Government investment trend 2006-2011 for the roads, it can be interpreted that the Government should invest to the R&D area more widely than before to promote element and core technology development for Green Highway Construction. Above all, small and mid-sized businesses have to be invested as well as encouraged to undertake green highwayrelated objects to accomplish the divisions which ranked high.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.1
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• pp.55-62
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• 2012

The present paper investigates the performance of the KOH aqueous solution as an absorbent to capture carbon dioxide ($CO_2$). The chemical absorption was carried out according to consecutive reactions that are generated in the order of $K_2CO_3$ and $KHCO_3$. The overall absorption was completed with following the physical absorption. When the absorption was conducted with the KOH as the limiting reactants in batch a reactor, $K_2CO_3$ production rate was the 1st order reaction for $OH^-$. However, $KHCO_3$ generation reaction was independent of the $CO_3^{2-}$ concentration and the rate was calculated to be $0.18gCO_2/min$ for all KOH absorbents, which is the same value of the reaction rate using $K_2CO_3$ aqueous solution as the absorbents. The overall $CO_2$ capture ratio of the 5% KOH absorbent was estimated to be 19% and the individual value in section 1 and 2 was 57 and 12%, respectively. The amount of $CO_2$ absorbed in the solution was very slightly less than the theoretical value, which was ascribed to the side reaction that produces $K_2CO_3{\cdot}KHCO_3{\cdot}1.5H_2O$ during the reaction and the consequent diminish in $CO_2$ absorption in the KOH solution.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.38-38
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• 2022

녹비작물은 천연비료로서 화학비료 사용량을 감소시키고 이산화탄소를 흡수해 농업분야에서 온실가스 저감을 위해 사용하고 있다. 녹비작물을 이용하여 지속가능한 친환경 농업의 필요성이 증대되고 있는 실정이다. 화본과 녹비작물은 두과 녹비작물에 비해 탄소 물질의 함량과 biomass가 상대적으로 높아 토양 내 유기물증진을 위한 재배에 적합하다. 이에 화본과 녹비작물 중 하나인 수단그라스의 발아 및 휴면특성 검정을 진행하여 발아 적정조건을 찾아 유기종자 생산기술 개발을 위한 자료로 활용하고자 한다. 본 연구에서는 수단그라스 4품종(GW104G, Cadan99B, TE-Evergreen, Sweet home)을 공시품종으로 사용하였다. 표준발아검사에 따라 각 품종별 종자를 100립씩 3반복 치상하여 10일간 발아검정 진행 후 발아율, 발아세, 평균발아일수, 발아속도를 조사하였다. 첫 번째 실험은 침종시간 및 치상온도별 실험으로 시간별(무처리/5/10/15/20/25hr)로 침종한 후, 생장상(10/20/30/40℃)에 보관하여 정상아 개수를 파악하였다. 두 번째 실험은 휴면타파 실험으로 1~5일 동안 종자를 예냉(무처리/5/10/15℃)과 고온(50℃) 처리한 후, 첫 번째 실험 결과에 따라 발아 최적 조건(침종 20hr, 치상온도 20℃)에서 발아시킨 후 정상아 개수를 파악하였다. 수단그라스 4품종의 치상온도별 발아율은 20℃에서 평균 92±6.9%로 가장 높았으며, TE-evergreen의 경우 치상온도 10℃에서 10시간, 20℃에서 20시간, 30와 40℃에서 15시간 침종한 값이 유의적으로 높은 발아율을 보였다. 수단그라스 4품종의 평균발아일수(MGT)는 침종 20시간과 치상온도 30℃일 때 평균 1.21±1.14일로 가장 빨랐으며 발아속도(GR)는 침종 20시간과 치상온도 20℃의 조건일 때 89.9±5.92로 가장 빨랐다. 수단그라스 4품종의 휴면타파 온도별 발아율은 10℃에서 평균 92±9.3%로 가장 높았다. TE-evergreen의 경우 휴면타파 온도 5, 10, 15℃에서 4~5일 동안 처리한 값이 무처리와 50℃처리에 비해 유의적으로 높은 발아율을 보였다. 수단그라스 발아검사 결과, 20시간 침종 후 20~40℃에서 2~3일간 발아시킬 경우 90%이상의 발아율을 보이므로 파종을 위한 종자 전처리를 할 경우 이와 같은 조건에서 진행하는 것이 바람직 할 것으로 사료된다.

• Journal of Korean Society of Disaster and Security
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• v.16 no.4
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• pp.45-59
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• 2023

The global focus on mitigating climate change has traditionally centered on carbon dioxide, but recent attention has shifted towards methane as a crucial factor in climate change adaptation. Natural settings, particularly aquatic environments such as wetlands, reservoirs, and lakes, play a significant role as sources of greenhouse gases. The accumulation of organic contaminants on the lake and reservoir beds can lead to the microbial decomposition of sedimentary material, generating greenhouse gases, notably methane, under anaerobic conditions. The escalation of methane emissions in freshwater is attributed to the growing impact of non-point sources, alterations in water bodies for diverse purposes, and the introduction of structures such as river crossings that disrupt natural flow patterns. Furthermore, the effects of climate change, including rising water temperatures and ensuing hydrological and water quality challenges, contribute to an acceleration in methane emissions into the atmosphere. Methane emissions occur through various pathways, with ebullition fluxes-where methane bubbles are formed and released from bed sediments-recognized as a major mechanism. This study employs Biochemical Methane Potential (BMP) tests to analyze and quantify the factors influencing methane gas emissions. Methane production rates are measured under diverse conditions, including temperature, substrate type (glucose), shear velocity, and sediment properties. Additionally, numerical simulations are conducted to analyze the relationship between fluid shear stress on the sand bed and methane ebullition rates. The findings reveal that biochemical factors significantly influence methane production, whereas shear velocity primarily affects methane ebullition. Sediment properties are identified as influential factors impacting both methane production and ebullition. Overall, this study establishes empirical relationships between bubble dynamics, the Weber number, and methane emissions, presenting a formula to estimate methane ebullition flux. Future research, incorporating specific conditions such as water depth, effective shear stress beneath the sediment's tensile strength, and organic matter, is expected to contribute to the development of biogeochemical and hydro-environmental impact assessment methods suitable for in-situ applications.

• Applied Chemistry for Engineering
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• v.9 no.1
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• pp.76-81
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• 1998

Physical adsorption on a silica gel(pore size of 80 nm, particle size of $10{\mu}m$)has been studied for binary mixture of acetone diluted in $CO_2$ by use of a FTIR transmission technique and we have compared the result of FTIR transmission technique with that of a chromatographic technique. Measurements were made at 313.2 K and under pressures up to 15MPa. As the pressure increases from 0.1MPa, the IA(Integral Absorbance) of the hydrogen-bonded OH groups interacting with acetone and adsorbed amount by use of a chromatographic technique increases at first, and reaches a maximum at a pressure below the critical pressure of $CO_2$, and then the intensities decrease gradually with increasing pressure. It is found that the pressure dependency of the chromatographic isotherm is a little larger than that of spectroscopic isotherm in the supercritical fluid region. This difference might be attributable to the weaker van der Waals force and relatively stronger hydrogen-bonding force influencing the adsorption of acetone on the sllica gel. The unique spectroscopic characteristics of amine group which vibrational frequencies of hydroxyl groups on the silica gel surface shift downward to about $1300cm^{-1}$ were measured from experimental result of triethylamine diluted in $CO_2$ or $N_2$.

• Microbiology and Biotechnology Letters
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• v.47 no.4
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• pp.630-638
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• 2019

Nitrous oxide (N₂O) is a greenhouse gas with a global warming potential 310 times higher than that of carbon dioxide. In this study, an N₂O-reducing consortium was obtained by enrichment culture using advanced treatment sludge as the inoculum. The dominant bacteria in the consortium were Sulfurovum (17.95%), Geobacter (14.63%), Rectinema (11.45%), and Chlorobium (8.24%). The consortium displayed optimal N₂O reducing activity when acetate was supplied as the carbon source at a carbon/nitrogen ratio (mol·mol^-1) of 6.3. The N₂O reduction rate increased with increasing N₂O concentration at less than 3,000 ppm. Kinetic analysis revealed that the maximum N₂O reduction rate of the consortium was 163.9 ㎍-N·g-VSS^-1·h^-1. Genes present in the consortium included nosZ (reduction of nitrous oxide to N₂), narG (reduction of nitrate to nitrite), nirK (reduction of nitrite to nitric oxide), and norB (reduction of nitric oxide to nitrous oxide). These results indicate that the N₂O-reducing consortium is a promising bioresource that can be used in denitrification and N₂O mitigation.

• Journal of the Korean GEO-environmental Society
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• v.13 no.9
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• pp.45-51
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• 2012

The calcium hydroxide$(Ca(OH)_2)$ which is the cement hydrate flowed into the tunnel by groundwater is reacted with microorganism in the soil, carbon dioxide$(CO_2)$ and the vehicle's exhaust gas$(SO_3)$. So its by-products are precipitated at the drainage pipe and these cause the drainage clogging. By this phenomenon, Degradation of water flow at the drainage system of the tunnel occurred and also pore water pressure is increased. Hence the acceleration of seepage and degradation of lining is occurred. The purpose of this study is to evaluate the field applicability of the Quantum Stick and Magnetic treatment in prevention of scale deposits at the Namsan ${\bigcirc}{\bigcirc}$ tunnel and the Zone ${\bigcirc}{\bigcirc}{\bigcirc}$ of subway. These technologies were installed into drainpipes with their performance monitored through occasional site visits. SEM and XRD were also performed on scale collected from these drainpipes. As a result, in case which factor technology is applied, scale creation is remarkably decreased and especially Quantum Stick treatment performing better than Magnetic treatment. Therefore, additional application of Quantum Stick or Magnetic treatment to the existing drainage is expected to decrease the drainage clogging of the drainage.

• Journal of Animal Environmental Science
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• v.18 no.1
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• pp.25-34
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• 2012

Noxious gases with malodorous substance concentrations in each stages of pig buildings were determined at a typical 400sow-scale farm to improve piggery environment. Using IAQ-300 and pDR-1000AN, continuous records for the concentration of $NH_3$, CO, $CO_2$, $NO_2$, $SO_2$, $H_2S$, $O_2$, and along with temperature, humidity, dust concentrates from individual pig pens were collected to analyze every 6 hours' condition of indoor environment for 24 hours' period. In most pig houses, the air quality at noon was good, while at night (00:00~06:00), air composition became noxious in all buildings. The order of buildings' air quality for 24 hrs was pregnant > farrowing > nursery > growing > finishing. The cause of air quality differences was presumed to be the differences of stocking density, defecating amount and the length of exposure time of slurry in indoors. In conclusion, well-designed building structure, proper control of stocking density, quick removal of excreta from pig pens and continuous ventilation are prerequisites to improve pig housing environment.

• Fire Science and Engineering
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• v.30 no.4
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• pp.65-72
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• 2016

This study examined the generation of combustion toxic gases of pinus rigida specimens processed with bis-(dimethylaminomethyl) phosphinic acid (DMDAP), bis-(diethylaminomethyl) phosphinic acid (DEDAP), and bis-(dibutylaminomethyl) phosphinic acid (DBDAP). Each pinus rigida plate was coated three times with 15 wt.% flame retardants in an aqueous solution. The specimens were then dried at room temperature. The production of combustion toxic gases was investigated using a cone calorimeter (ISO 5660-1). The first time to peak mass loss rate ($1^{st}-TMLR_{peak}$) processed with the chemical additives decreased to 5.9 from 41.2% compared with the unprocessed specimen. The second time to the peak mass loss rate ($2^{nd}-TMLR_{peak}$) for the processed specimens was decreased 1.8% for DMDAP and 5.3% for DBDAP and increased 1.8% for DEDAP. The peak carbon monoxide ($CO_{peak}$) production was 1.5 to 2.0 times higher than that of the unprocessed plate. The peak carbon dioxide ($CO_{2peak}$) production was reduced 0.01 times for DMDAP and increased 1.15 to 1.19 times for DEDAP and DBDAP compared with the unprocessed specimens. In particular, the oxygen concentration was much higher than 15%, which can be fatal to humans and the resulting hazard can be eliminated. Overall, the combustion toxicity of flammable gas were increased partially by the chemical additives compared with those of the unprocessed plate.