• Title/Summary/Keyword: environmental modification

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Estimating the lateral profile of helical piles using modified p-y springs

  • Hyeong-Joo Kim;Hyeong-Soo Kim;Peter Rey Dinoy;James Vincent Reyes;Yeong-Seong Jeong;Jun-Yong Park;Kevin Bagas Arifki Mawuntu
    • Geomechanics and Engineering
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    • v.35 no.1
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    • pp.1-11
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    • 2023
  • A growing trend of utilizing helical piles for soft soil strata to support infrastructure projects is currently observed in Saemangeum, South Korea. Recognized mainly due to its ease of installation and reusability proves to be far more superior compared to other foundation types in terms of sustainability. This study applies modified p-y springs to characterize the behavior of a laterally loaded helical pile with a shaft diameter of 89.1 mm affixed with 3 helices evenly spaced along its embedded length of 2.5 m. Geotechnical soil properties are correlated from CPT data near the test bed vicinity and strain gauges mounted on the shaft surface. A modification factor is applied on the p-y springs to adjust the simulated data and match it to the bending moment, soil resistance and deflection values from the strain gauge measurements. The predicted lateral behavior of the helical pile through the numerical analysis method shows fairly good agreement to the recorded field test results.

Selective removal of cationic dye pollutants using coal ash-derived zeolite/zinc adsorbents

  • Chatchai Rodwihok;Mayulee Suwannakaew;Sang Woo Han;Siyu Chen;Duangmanee Wongratanaphisan;Han S. Kim
    • Membrane and Water Treatment
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    • v.14 no.3
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    • pp.121-128
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    • 2023
  • This study introduces a NaOH/Zn-assisted hydrothermal method for the synthesis of zeolites derived from coal ash (CA). A zeolite/Zn adsorbent is successfully prepared by the activation of CA with NaOH and Zn; it is characterized by a high surface area and a negative surface charge.Methylene blue (MB) and methyl orange (MO) are selected as dye pollutants, and their adsorption onto the zeolite/Zn adsorbent is investigated. Results show the high adsorption capacities of MB and MO and that the negative surface charge facilitates electrostatic interactions between the adsorbates and adsorbents. The zeolite/Zn adsorbents shows the selective adsorption of positively charged dye MB via electrostatic interactions between the =NH+ group (positive dipole) and the oxygen functional group of the adsorbents (negative dipole). The selectivity for the positively charged dye is sufficiently high, with the removal efficiency reaching 99.41% within 10 min. By contrast, the negatively charged dye MO exhibits negligible absorption. These findings confirm the role of electrostatic interactions in the adsorption of MB, in addition to the effect of a large surface area. The results of this study are expected to facilitate the development of simple, eco-friendly, and cost-effective zeolite-based adsorptive composites from CA residuals for the selective removal of dye pollutants from CA waste.

Analysis of the Status and Limitation of the Biotope Area Ratio on Strategic Environmental Impact Assessment and Environmental Impact Assessment (전략환경영향평가 및 환경영향평가 사업에서의 생태면적률 적용 현황 및 한계점 분석)

  • Park, Jin-Han;Lee, Dong-Kun;Kim, Hyo-min;Sung, Hyun-Chan;Jeon, Seong-Woo;Choi, Jae-yong;Lee, Chang-Seok;Hwang, Sang-Yeon
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.21 no.1
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    • pp.55-71
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    • 2018
  • To improve the ecological function of urban areas, the guideline for applying the Biotope Area Ratio to the Environmental Impact Assessment (EIA) was developed in 2005 and modified in the July, 2017. This study investigates whether the guideline has been actually practiced in the real world by searching reports including 648 cases of the Strategic Environmental Impact Assessment (SEIA) and 471 cases of the EIA. The results show that the 38% of SEIA and the 43% of EIA include sections about Biotope Area Ratio, and the 15% of SEIA and the 25 % of EIA are satisfied the threshold of the Biotope Area Ratio suggested by the guideline. The statistical analysis results show that this low level of practice was not improved through the modification of the guideline in 2017. This is because the guideline is forcibleness, its explanation is unclear, and stockholders' understanding of it lacks. In addition, lack of tracking management on SEIA and EIA also contributes to the low level of practice of the guideline. To promote the practice, the efforts to legislate and publicize the guideline are required.

Shrinkproofing of Wool Fabrics by Pulse Corona Discharge and Enzymes

  • Cho, Sung-Mi;Toru Takagishi;Mitsuru Tahara
    • Proceedings of the Korean Fiber Society Conference
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    • 2003.10a
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    • pp.96-96
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    • 2003
  • In this article modification of wool fibers and fabrics by pulse corona discharge and enzymes, in particular purified keratinase with a single component has been carried out to improve their surface properties. The shrinkproofing, tensile strength, weight loss, and the primary hand values calculated from the mechanical properties of the dual treated wool fabrics were investigated. In addition, the surface morphology of wool fiber was observed under the dry and wet conditions using an environmental SEM, ESEM.

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Intelligent Control by Immune Network Algorithm Based Auto-Weight Function Tuning

  • Kim, Dong-Hwa
    • 제어로봇시스템학회:학술대회논문집
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    • 2002.10a
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    • pp.120.2-120
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    • 2002
  • In this paper auto-tuning scheme of weight function in the neural networks has been suggested by immune algorithm for nonlinear process. A number of structures of the neural networks are considered as learning methods for control system. A general view is provided that they are the special cases of either the membership functions or the modification of network structure in the neural networks. On the other hand, since the immune network system possesses a self organizing and distributed memory, it is thus adaptive to its external environment and allows a PDP (parallel distributed processing) network to complete patterns against the environmental situation. Also. It can provi..

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Modification of Miller-Holzworth model for Korea (국내 적용을 위한 Miller-Holzworth 모델의 수정)

  • 장영기
    • Journal of Korean Society for Atmospheric Environment
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    • v.11 no.3
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    • pp.299-302
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    • 1995
  • Many air quality models have been used for Environmental impact assessments. Miller-Holzworth model suggested by Holzworth is a simple air quality model is frequently used for air quality assessments in korea. Miller-Holzworth model suggested by Holzworth is a simple air quality model for the ground-level area source, The model estimates the pollutants concentration averaged over the wind centerline. An error involved in the Miller-Holzworth model was first indentified by Calder in 1977. But the model has been used without correction for unsuitable cases in Korea. This paper corrected that error and modified model formulation for application to urban and rural areas.

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Safety evaluation of gene therapy - a case study of naked DNA product

  • Ahn, Byung-Ok
    • Proceedings of the Korean Society of Toxicology Conference
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    • 2003.10b
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    • pp.86-86
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    • 2003
  • Gene therapy is a medical intervention based on modification of the genetic material of living cells. Gene transfer usually conducted using bacterial plasmid DNA and/or virus vector to express a specific protein. Gene transfer medicinal products classified as naked nucleic acid, complexed nucleic acid or non-viral vectors, viral vector, and genetically modified cells according to biological origin.(omitted)

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A Study on Improvements in the Korean Decimal Classification System for Environmental Studies (한국십진분류법의 환경학 분야 개선방안에 관한 연구)

  • Chung, Yeon-Kyoung;Chang, Yun-Mee
    • Journal of the Korean BIBLIA Society for library and Information Science
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    • v.22 no.4
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    • pp.231-250
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    • 2011
  • The purposes of this study are to review characteristics and research areas of environmental studies; to compare and analyze environmental studies in research classifications and Korean societies from Korea Research Foundation(KRF) as well as decimal classification systems such as KDC, DDC, NDC and to suggest several modifications for environmental studies in KDC for the next edition. First of all, environmental philosophy, environmental sociology, environmental education, environmental toxicology, environmental architecture, and environmental geography are suggested to add to the main schedule in KDC and -0276 green technology(environmental technology) is suggested to add to Table 1. Standard subdivision. And new classification numbers for environmental law and environmental public administration are suggested in law and public administration.

Characteristics of Sensible Heat and Latent Heat Fluxes over the East Sea Related with Yeongdong Heavy Snowfall Events (영동대설 사례와 관련된 동해상의 현열속과 잠열속 분포 특성)

  • Kim, Ji-Eon;Kwon, Tae-Yong;Lee, Bang-Yong
    • Ocean and Polar Research
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    • v.27 no.3
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    • pp.237-250
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    • 2005
  • To investigate the air mass modification related with Yeongdong Heavy snowfall events, we examined sensible and latent heat fluxes on the East Sea, the energy exchange between atmosphere and ocean in this study. Sensible and latent heats were calculated by a bulk aerodynamic method, in which NCEP/NCAR reanalysis data and NOAA/AVHRR weekly SST data with high resolution were used. Among winter precipitation events in the Yeongdong region, 19 heavy precipitation events $(1995{\sim}2001)$ were selected and classified into three types (mountain, cold-coastal, and warm types). Mountain-type precipitation shows highly positive anomalies of sensible and latent heats over the southwestern part of the East Set When separating them into the two components due to variability of wind and temperature/ specific Humidity, it is shown that the wind components are dominant. Cold-coastal-type precipitation also shows strong positive anomalies of sensible and latent heats over the northern part and over the central-northern part of the East Sea, respectively. It is shown that the sensible heat anomalies are caused mostly by the decrease of surface air temperature. So it can be explained that cold-coastal-type precipitation is closely related with the air mass modification due to cold air advection over warm ocean surface. But in warm-type precipitation, negative anomalies are found in the sensible and latent heat distributions. From this result, it may be postulated that warm-type precipitation is affected by the internal process of the atmosphere rather than the atmosphere-ocean interaction.