• 제목/요약/키워드: Stripping

검색결과 648건 처리시간 0.041초

Electrochemical Determination of As(III) at Nanoporous Gold Electrodes with Controlled Surface Area

  • Seo, Min Ji;Kastro, Kanido Camerun;Kim, Jongwon
    • 대한화학회지
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    • 제63권1호
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    • pp.45-50
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    • 2019
  • Because arsenic (As) is a chemical substance toxic to humans, there have been extensive investigations on the development of As detection methods. In this study, the electrochemical determination of As on nanoporous gold (NPG) electrodes was investigated using anodic stripping voltammetry. The electrochemical surface area of the NPG electrodes was controlled by changing the reaction times during the anodization of Au for NPG preparation, and its effect on the electrochemical behavior during As detection was examined. The detection efficiency of the NPG electrodes improved as the roughness factor of the NPG electrodes increased up to around 100. A further increase in the surface area of the NPG electrodes resulted in a decrease of the detection efficiency due to high background current levels. The most efficient As detection efficiency was obtained on the NPG electrodes prepared with an anodization time of 50 s. The effects of the detection parameters and of the Cu interference in As detection were investigated and the NPG electrode was compared to flat Au electrodes.

Application of magnetic activated sludge process for a milking parlor wastewater treatment with nitrogen and phosphorus recovery

  • Onodera, Toshihito;Sakai, Yasuzo;Kashiwazaki, Masaru;Ihara, Ikko;Lal, Saha Mihir
    • 한국초전도ㆍ저온공학회논문지
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    • 제23권3호
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    • pp.20-25
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    • 2021
  • Milking parlor wastewater contains high concentration suspended solid (SS), nitrogen, and/or phosphate as well as organic compounds. A new biological wastewater process by magnetic separation, magnetic activated sludge (MAS) process, was applied to milking parlor wastewater treatment process. A three step wastewater treatment process of coagulation sedimentation / ammonia stripping (C/S), magnetic activated sludge process and contact oxidation (CO) was proposed for removal of these pollutants. First step, C/S process recovered 96% TN and 96% PO43--P as resource for fertilizer from the wastewater. 81% biochemical oxygen demand (BOD) in wastewater was removed after MAS process. As a results, all pollutant concentrations satisfied Japanese effluent standards. Most of residual BOD and SS were removed by the CO process. It was estimated that the proposed process could reduce the process space to 1/7.

Efficient extraction and recovery of Lignosulfonate using sunflower oil as green solvent in liquid membrane transport: Equilibrium and kinetic study

  • Kumar, Vikas;Singh, Raghubansh K.;Chowdhury, Pradip
    • Journal of Industrial and Engineering Chemistry
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    • 제67권
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    • pp.109-122
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    • 2018
  • This work highlights extraction and removal of Lignosulfonate using sunflower oil-Tri-n-octylamine (TOA) system in bulk liquid membrane transport. Maximum extraction and recovery percentages of 92.4% and 75.2% were achieved. Optimum manifold operating conditions were: 4 vol.% TOA, $2{\pm}0.1$ feed phase pH, 300 rpm stirring speed, at $40^{\circ}C$ with 0.2 (M) $Na_2SO_4$ solution. 1:2 (organic/aqueous) and 1:1 (aqueous/aqueous) phase ratios produced best results. Extraction (36.85 kJ/mol) was found to be intermediate controlled and stripping (54.79 kJ/mol) was chemical reaction controlled. Kinetic estimation of data with higher rate constants for stripping vis-${\grave{a}}$-vis extraction showed latter to be rate determining.

주입 보수공법 적용시 콘크리트의 드릴링 가능 시기 고찰 (Decision of Optimum Drilling Time for the Injection Based Repair Methods of the Impaired Concrete)

  • 한수환;최윤호;현승용;김종;한민철;한천구
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2020년도 봄 학술논문 발표대회
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    • pp.134-135
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    • 2020
  • In this study, optimum time of drilling for injection of repair material was determined through surface stripping and cracking investigation by drilling from the 1 days to the 3 days of the age for the specimens with ∅100 mm. No surface stripping and cracking occurred on the third day of age, and the compressive strength value was above 14 MPa, which resulted in the appropriate time for drilling on the third day of age.

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Deep polarization observations of a ram pressure stripped galaxy, NGC 4522

  • Choi, Woorak;Chung, Aeree;Kim, Chang-goo;Lee, Bumhyun
    • 천문학회보
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    • 제45권1호
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    • pp.65.1-65.1
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    • 2020
  • We present high-resolution, high-sensitivity continuum data of NGC 4522 observed at 3 cm (X-band) and 10 cm (S-band) in full polarization mode using the JVLA. This observation has 2 - 4 times better spatial resolution and 2 - 5 times better sensitivity compared to previous continuum observations. NGC 4522 is a Virgo spiral galaxy undergoing active ram pressure stripping. This galaxy is particularly well known for the CO emission detected outside its stellar disk, some of which coincides with the extraplanar HI gas and Halpha patches. The major goal of our JVLA observation is to leverage our understanding of the influence of the ram pressure on the general ISM field and multi-phase medium. By combining our new deep radio continuum data and previous observations, we will investigate how the B-field properties can be affected by the ram pressure, and what roles the B-field plays in the stripping process of the multi-phased ISM and in the star formation activity when the ram pressure is present.

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A novel simulation technique invented for studying low-surface brightness features in and around galaxies: Galaxy Replacement Technique (GRT)

  • Shin, Jihye;Chun, Kyungwon;Smith, Rory;Ko, Jongwan
    • 천문학회보
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    • 제46권2호
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    • pp.57.1-57.1
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    • 2021
  • K-SIM (KASI-Simulation) research project is dedicated to develop new numerical techniques in order to theoretically study galaxy formation and evolution. As the first step of the K-SIM, to model tidal stripping of galaxies with a very high resolution in a fully cosmological context, we invented the Galaxy Replacement Technique (GRT) that is very efficient and fast. The high resolution allows us to accurately resolve the tidal stripping process and well describe the formation of ultra-low surface brightness features in the galaxy cluster (㎶ < 32 mag/arcsec^2), such as the intra-cluster light, shells and tidal streams. I'll introduce how the GRT is designed and which science topics in low-surface brightness regime can be visited using the GRT.

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