• Resources Recycling
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• v.25 no.2
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• pp.17-24
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• 2016

This study aims at evaluating environmental impacts on recycling process of used small household appliances. The recycling process mainly consists of manual dismantling, crushing and various sorting processes to effectively recover valuable resources and to minimize environmental impact. In this study, life-cycle assessment (LCA) methodology is applied to analyze major environmental parameters such as GWP, ADP, POCP, EP, etc. One of the major impact categories on the weight basis in the recycling process is global warming (GWP) 57.1%, next to ADP 35.4% and POCP 4.8%, respectively. As a result of environmental impact on recovery of valuable resources/ton, the GWP of plastics for ABS is highest (33.7%) compared to ferrous metals (9.4%). The effects of environmental and economical benefit are also analyzed to compare with the amount of virgin materials to be recycled by recycled materials. In addition, recycled materials are also more economical in comparison to virgin materials due to the environmental avoiding effect by recycling. In conclusion, the key environmental issues related to the recycling of e-wastes are analyzed and therefore, the effective recycling process will contribute to mitigate global warming potential in the near future.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.975-983
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• 2022

This paper presents an innovative way of integrating scheduling and project controls with the environmental impact of a construction project to track, monitor, and manage environmental emissions at the activity level. As a starting point, scheduling and project controls help monitor the status of a project to provide an assessment of the duration and sequence of activities. Additionally, project schedules can also reflect resource allocation and costs associated with various phases of a construction project. Owners, contractors and construction managers closely monitor tasks or activities on the critical path(s) and/or longest path(s) calculated through network based scheduling techniques. However, existing industry practices do not take into account environmental impact associated with each activity during the life cycle of a project. Although the environmental impact of a project may be tracked in various ways, that tracking is not tied to the project schedule and, as such, generally is not updated when schedules are revised. In this research, a Cradle to Gate approach is used to estimate environmental emissions associated with each activity of a sample project schedule. The research group has also investigated the potential determination of scenarios of lowest environmental emissions, just as project managers currently determine scenarios with lowest cost or time. This methodology can be scaled up for future work to develop a library of unit emissions associated with commonly used construction materials and equipment. This will be helpful for project owners, contractors, and construction managers to monitor, manage, and reduce the carbon footprint associated with various projects.

• Geomechanics and Engineering
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• v.38 no.6
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• pp.621-631
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• 2024

In designing earthquake-resistant structures, we traditionally select dynamic loads based on the recurrence period of earthquakes, using individual seismic records or aligning them with the design spectrum. However, these records often represent isolated waveforms lacking continuity, underscoring the need for a deeper understanding of natural seismic phenomena. The Earth's crustal movement, both before and after a significant earthquake, can trigger a series of both minor and major seismic events. These minor earthquakes, which often occur in short time before or after the major seismic events, prompt a critical reassessment of their potential impact on structural design. In this study, we conducted a detailed tunnel response analysis to assess the impact of both single mainshock and multiple earthquake scenarios (including foreshock-mainshock and mainshock-aftershock sequences). Utilizing numerical analysis, we explored how multiple earthquakes affect tunnel deformation. Our findings reveal that sequential seismic events, even those of moderate magnitude, can exert considerable stress on tunnel lining, resulting in heightened bending stress and permanent displacement. This research highlights a significant insight: current seismic design methodologies, which predominantly focus on the largest seismic intensity, may fail to account for the cumulative impact of smaller, yet frequent, seismic events like foreshocks and aftershocks. Our results demonstrate that dynamic analyses considering only a single mainshock are likely to underestimate the potential damage (i.e., ovaling deformation, failure lining, permanent displacement etc.) when compared to analyses that incorporate multiple earthquake scenarios.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.12
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• pp.698-705
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• 2017

Environmental impact of a mobile phone charger containing recycled plastic was quantified using LCA and the environmental benefits from the use of recycled and virgin plastic were compared. The assessment considers potential environmental impacts across the whole life cycle of the charger including; pre-manufacturing; manufacturing; distribution; product use; and end-of-life stages and quantified six environmental impact categories; Abiotic depletion; Acidification; Eutrophication; Global warming; Ozone layer depletion; and Photochemical oxidants creation. The study showed that the environmental impacts of the use stage accounted for 94.4% and 70% in the resource depletion and global warming impact categories, respectively, and the environmental impacts of the pre - manufacturing stage accounted for more than 98% in the other impact categories. The main cause of the environmental impacts in the use stage was electricity consumed by the charger. The main cause in the pre-manufacturing stage was PBA (Printed Board Assembly) and external case manufacturing. In order to quantify the environmental benefits of recycled PC (Polycarbonate) in the exterior case, the environmental impacts of 1 kg production of recycled PC and virgin PC were evaluated. The environmental impact on the abiotic depletion of the recycled PC is estimated to be 30% compared to the virgin PC, and the impacts on the other impact categories of the recycled PC were less than 5% of the virgin plastic. Sensitivity analysis was performed for 12 items including site data and assumptions made. The sensitivity of each item was less than 10%. The results of this study confirm that designing compact and light PBA, improving charging efficiency, and use of recycled plastic are important design factors to reduce the environmental impact of a charger.

• Journal of the Korean Association of Geographic Information Studies
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• v.25 no.2
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• pp.72-87
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• 2022

For the sustainable development and conservation of the national land, planned development and efficient environmental conservation must be accompanied. To this end, it is possible to induce development and conservation to harmonize by deriving factors affecting development through analysis of previously developed areas and applying appropriate management measures to areas with high development pressure. In this study, the relationship between the area where the land cover changed from forest to urbanization and various social, geographical, and restrictive factors was implemented in a regression formula through logistic regression analysis, and potential development sites were analyzed for Yongin City. The factor that has the greatest impact on the analysis of potential development area is the restrict factors such as Green Belt and protected areas, and the factor with the least impact is the population density. About 148km²(52%) of Yongin-si's forests were analyzed as potential development area. Among the potential development sites, the area with excellent environmental value as a protected area and 1st grade on the Environment Conservation Value Assessment Map was derived as about 13km². Protected areas with high development potential were riparian buffer zone and special measurement area, and areas with excellent natural scenery and river were preferred as development areas. Protected areas allow certain actions to protect individual property rights. However, there is no clear permit criteria, and the environmental impact of permits is not understood. This is identified as a factor that prevents protected areas from functioning properly. Therefore, it needs to be managed through clear exception permit criteria and environmental impact monitoring.

• Journal of Environmental Impact Assessment
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• v.23 no.2
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• pp.101-111
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• 2014

The research was carried out in order to find climate factors which determine the distribution of Neolitsea sericea, and the potential habitats (PHs) under the current climate and three climate change scenario by using species distribution models (SDMs). Four climate factors; the minimum temperature of the coldest month (TMC), the warmth index (WI), summer precipitation (PRS), and winter precipition (PRW) : were used as independent variables for the model. Three general circulation models under A1B emission scenarios were used as future climate scenarios for the 2050s (2040~2069) and 2080s (2070~2099). Highly accurate SDMs were obtained for N. sericea. The model of distribution for N. sericea constructed by SDMs showed that minimum temperature of the coldest month (TMC) is a major climate factor in determining the distribution of N. sericea. The area above the $-4.4^{\circ}C$ of TMC revealed high occurrence probability of the N. sericea. Future PHs for N. sericea were projected to increase respectively by 4 times, 6.4 times of current PHs under 2050s and 2080s. It is expected that the potential of N. sericea habitats is expanded gradually. N. sericea is applicable as indicator species for monitoring in the Korean Peninsula. N. sericea is necessary to be monitored of potential habitats.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.22 no.1
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• pp.33-45
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• 2019

Compound disaster is the type that increases the impact affected by two or more hazard events, and attention to compound disaster and multi-hazards risk is growing due to potential damages which are difficult to predict. The objective of this study is to analyze the possible impacts of post-fire landslide scenario quantitatively by using TRIGRS (Transient Rainfall Infiltration and Grid-Based Regional Slope-Stability Analysis), a physics-based landslide model. In the case of wildfire, soil organic material and density are altered, and saturated hydraulic conductivity decrease because of soil exposed to high temperature. We have included the change of soil saturated hydraulic conductivity into the TRIGRS model through literature review. For a case study, we selected the area of $8km^2$ in Pyeongchang County. The landslide modeling process was calibrated before simulate the post-wildfire impact based on landslide inventory data to reduce uncertainty. As a result, the mean of the total factor of safety values in the case of landslide was 2.641 when rainfall duration is 1 hour with rainfall intensity of 100mm per day, while the mean value for the case of post-wildfire landslide was lower to 2.579, showing potential landslide occurrence areas appear more quickly in the compound disaster scenario. This study can be used to prevent potential losses caused by the compound disaster such as post-wildfire debris flow or landslides.

• Journal of Urban Science
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• v.12 no.2
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• pp.7-12
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• 2023

The purpose of this study is to explore the issue of antibiotic misuse and the associated environmental problems, focusing on the antibiotic sulfamethoxazole used in animal agriculture. Antibiotic resistance is currently a global problem, exacerbated by the misuse of antibiotics in agriculture and animal husbandry. This study emphasizes the importance of investigating the potential environmental toxicity of antibiotics and discovering efficient treatment technologies. It discusses the use of advanced oxidation processes and artificial wetlands as potential approaches to mitigate the environmental impact of antibiotics, particularly sulfamethoxazole. In conclusion, the study underscores the need for research, data collection, monitoring, and effective environmental protection policies to combat antibiotic misuse and environmental pollution. It also emphasizes the significance of raising awareness and implementing proactive measures to address these issues.

• Journal of Korean Society on Water Environment
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• v.23 no.4
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• pp.535-542
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• 2007

The Geumho river watershed located in the middle of the Nakdong river has been threatened by high population growth and urbanization. Of concern specifically is the potential impact of future developments in the watershed on the reduction of base flow and the consequent risk of degradation of ecological habitats in Geumho river. Anticipated increase in imperviousness, on the other hand, is expected to elevate flood risk and the associated environmental damage. A watershed hydrology based modeling study is initiated in this study to assist in planning for sustainable future development in the Geumho river watershed. The Soil and Water Assessment Tool (SWAT) is selected to model the impact of urbanization in the Geumho river watershed on the hydrologic response thereof. The modeling results show that in general the likelihood that the watershed will experience high and low stream flows will increase in view of the urbanization so far achieved.

• Journal of Korean Society for Atmospheric Environment
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• v.27 no.5
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• pp.534-544
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• 2011

The secondary aerosol forming potential of ambient air was first measured with the Potential Aerosol Mass(PAM) chamber at Gosan supersite on Jeju island from October 22 to November 5, 2010. PAM chamber is a small flowthrough photo-oxidation chamber with extremely high OH and $O_3$ levels. The OH exposure in the PAM chamber was $(2{\pm}0.4){\times}10^{11}{\sim}(6{\pm}1.2){\times}10^{11}$ molecules $cm^{-3}$ s and was similar to 2 to 5 days of aging in the atmosphere. By periodically turning on and off UV lamps in the PAM chamber, ambient aerosol and newly formed aerosol (e.g. called as PAM aerosol) was alternately measured. Aerosol number and mass concentration in the range of 10~487 nm in diameter was measured by SMPS 3034. With UV lamps on, the nucleation mode particles smaller than 50 nm in diameters were formed. Their number concentration was greater than 105 $cm^{-3}$, leading to increase in aerosol mass by 0~8 ${\mu}gm^{-3}$. The variations of PAM and ambient aerosols were greatly dependent on characteristics of air masses such as precursor concentrations and degree of aging. This preliminary results suggests that PAM chamber is useful to assess the aerosol formation potential of air mass and its impact on the air quality. The further analysis of data with gaseous and particulate measurements will be done.