• Title/Summary/Keyword: Environment Technology

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Characterization of Radiation Fabricated Imidazole Based Hydrogel (이미다졸 기반 수화겔의 방사선 합성 및 특성 평가)

  • Gwon, Hui-Jeong;Jeong, Jin-Oh;Jeong, Sung In;Park, Jong-Seok;Lim, Youn-Mook
    • Journal of Radiation Industry
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    • v.12 no.4
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    • pp.349-353
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    • 2018
  • Metronidazole (MD), which is used as an antibiotic, is largely used as an oral and skin application agent, and has inhibiting effect on the production of the fungus causing malodor. However, the maximum drug inclusion concentration is 0.75% of skin ointment in commercially available. In this study, hydrogels containing high concentration of metronidazole were prepared by using radiation crosslinking technique based on biocompatible polymers, and release characteristics and antimicrobial properties were evaluated. This study was preliminary carried out to investigate whether it could be used effectively as antibacterial dressing materials.

Sodium titanate as an infrared reflective material for cool roof application

  • Ullah, Mahboob;Kim, Hee Jung;Heo, Jae Gu;Roh, Dong Kyu;Kim, Dae-Sung
    • Journal of Ceramic Processing Research
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    • v.20 no.spc1
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    • pp.86-91
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    • 2019
  • A solid-state route was used to prepare sodium titanium oxide (NTO, Na2Ti3O7) as a solar heat protecting material with an impressive solar reflectance (TSR = 94.3%) using a high refractive index rutile TiO2. The solar reflectance of the synthesized NTO was measured using UV-Vis-NIR spectrophotometer. Solar reflectance property of the synthesized compound depends on the calcination temperature. The solar reflectance property of the synthesized NTO powder was compared with commercial rutile TiO2. The compound synthesized at 900 ℃ for 24 hrs had remarkable solar reflectance 94.3% than that calcined below 900 ℃. Crystalline nature, structural property, morphology and optical properties of NTO powders were characterized and analyzed using XRD, FE-SEM, EDS and UV-Vis-NIR spectrophotometer. From the results, we guessed that NTO would be a suitable "solar heat protecting candidate" for energy-saving applications in coating industries.

Dose Evaluation of Neutron within Containment Building of a CE type Nuclear Power Plant (CE형 원전의 격납건물내 중성자선량 평가)

  • Kim Tae Wook;Han Jae Mun;Kim Kyung Doek;Yun Cheol Whan;Suh Jang Soo;Kim Young Jae
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.3 no.1
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    • pp.23-30
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    • 2005
  • From measured results of the neutron fields at some principal places within the containment building in a CE type nuclear power plant in operation, the radiation exposure of a worker to the neutron at there was evaluated and the equivalent dose reflecting new recommendation (ICRP 60) was compared with that doing the old one (ICRP 26). The measured neutron field was also compared with calibration neutron field. From the analysis, the following conclusion was obtained: the average neutron radiation weighting factor according to new recommendation is 2.41 to 2.71 times higher than the old one. The average neutorn radiation weighting factor at the measured place was similar to that at calibration neutron field. The average neutron energy at measured place was between 42 and 158 keV and higher than that of calibration field of 500 keV. So, the measured equivalent dose in nuclear power plant could be overestimated compared to the real equivalent dose.

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Development of Detection Method for Cyclomaltodextrinase Family Genes using Degenerate PCR Primers

  • Oh, Su-Won;Jang, Myoung-Uoon;Jeong, Chang-Ku;Yuk, Jeong-Bin;Park, Jung-Mi;Park, Kwan-Hwa;Kim, Tae-Jip
    • Food Science and Biotechnology
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    • v.15 no.6
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    • pp.967-974
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    • 2006
  • Cyclomaltodextrinases (CDases), maitogenic amylases, and neopullulanases share highly conserved primary structures and similar characteristics, and are thus classified into the same family. BLAST search has showed that a variety of bacterial strains harbor putative CDase family genes with several well-conserved motif amino acid sequences. In this study, four degenerate polymerase chain reaction (PCR) primer sets were designed for the detection of CDase genes, on the basis of their highly conserved amino acid blocks (WYQIFP, DGWRLD, LGSHDT, and KCMVW). The PCR detection conditions were optimized and the detection specificity of each for the primer sets was tested against the genomic DNAs isolated from 23 different Bacillus-associated species. Consequently, all tested primer sets evidenced successful amplification of specific PCR products in length, which share 55-98% amino acid sequence identity with known and putative CDases. The primers developed herein, therefore, can be applied for the easy and efficient detection and isolation of CDase family genes for the modification of functional food carbohydrates.

Vitrification of Simulated Combustible Dry Active Wastes in a Pilot Facility

  • Yang, Kyung-Hwa;Park, Seung-Chul;Lee, Kyung-Ho;Hwang, Tae-Won;Maeng, Sung-Jun;Shin, Sang-Woon
    • Nuclear Engineering and Technology
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    • v.33 no.4
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    • pp.355-364
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    • 2001
  • In order to evaluate and finally optimize the vitrification condition for combustible dry active waste (DAW), dust and gas generation characteristics were investigated for PE, cellulose, and mixed waste Tests were conducted by varying the operation variables such as melter configuration, excess oxygen amount, and waste feeding rate. Results showed that dust generation characteristics were affected by the operation parameters and the melter's configuration is the dominant one. For all tested DAWs, dust generation was reduced by increasing the waste feeding rate and the excessive oxygen amount in the melter. Among waste types, dust amount was decreased by the order of mixed wastes, PE, and cellulose. Other parameters such as temperature variation and operation time have also affected the dust generation. The optimum condition for the DAW vitrification was determined as the melter's configuration equipped for minimizing the waste dispersion with 20 kg/h of waste feeding rate and 100% of excessive oxygen supply. CO gas concentration in the off-gas was immediately influenced by the combustion state in the melter, but showed similar trend as the dust generation. For the NOx production during the vitrification process, thermal NOx, which is generated from the Post Combustion Chamber (PCC), rather than fuel NOx was assumed to be dominant. The gas cleaning of efficiencies of the PCC, wet scrubber, and Selective Catalytic Reduction system (SCR) were found to be high enough to keep the concentration of pollutants (CO, NOx, SOx, HCI) in the stack below their relevant emission limits.

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Development of an efficient method of radiation characteristic analysis using a portable simultaneous measurement system for neutron and gamma-ray

  • Jin, Dong-Sik;Hong, Yong-Ho;Kim, Hui-Gyeong;Kwak, Sang-Soo;Lee, Jae-Geun;Jung, Young-Suk
    • Analytical Science and Technology
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    • v.35 no.2
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    • pp.69-81
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    • 2022
  • The method of measuring and classifying the energy category of neutrons directly using raw data acquired through a CZT detector is not satisfactory, in terms of accuracy and efficiency, because of its poor energy resolution and low measurement efficiency. Moreover, this method of measuring and analyzing the characteristics of low-energy or low-activity gamma-ray sources might be not accurate and efficient in the case of neutrons because of various factors, such as the noise of the CZT detector itself and the influence of environmental radiation. We have therefore developed an efficient method of analyzing radiation characteristics using a neutron and gamma-ray analysis algorithm for the rapid and clear identification of the type, energy, and radioactivity of gamma-ray sources as well as the detection and classification of the energy category (fast or thermal neutrons) of neutron sources, employing raw data acquired through a CZT detector. The neutron analysis algorithm is based on the fact that in the energy-spectrum channel of 558.6 keV emitted in the nuclear reaction 113Cd + 1n → 114Cd + in the CZT detector, there is a notable difference in detection information between a CZT detector without a PE modulator and a CZT detector with a PE modulator, but there is no significant difference between the two detectors in other energy-spectrum channels. In addition, the gamma-ray analysis algorithm uses the difference in the detection information of the CZT detector between the unique characteristic energy-spectrum channel of a gamma-ray source and other channels. This efficient method of analyzing radiation characteristics is expected to be useful for the rapid radiation detection and accurate information collection on radiation sources, which are required to minimize radiation damage and manage accidents in national disaster situations, such as large-scale radioactivity leak accidents at nuclear power plants or nuclear material handling facilities.

Adaptive State-of-Charge Estimation Method for an Aeronautical Lithium-ion Battery Pack Based on a Reduced Particle-unscented Kalman Filter

  • Wang, Shun-Li;Yu, Chun-Mei;Fernandez, Carlos;Chen, Ming-Jie;Li, Gui-Lin;Liu, Xiao-Han
    • Journal of Power Electronics
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    • v.18 no.4
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    • pp.1127-1139
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    • 2018
  • A reduced particle-unscented Kalman filter estimation method, along with a splice-equivalent circuit model, is proposed for the state-of-charge estimation of an aeronautical lithium-ion battery pack. The linearization treatment is not required in this method and only a few sigma data points are used, which reduce the computational requirement of state-of-charge estimation. This method also improves the estimation covariance properties by introducing the equilibrium parameter state of balance for the aeronautical lithium-ion battery pack. In addition, the estimation performance is validated by the experimental results. The proposed state-of-charge estimation method exhibits a root-mean-square error value of 1.42% and a mean error value of 4.96%. This method is insensitive to the parameter variation of the splice-equivalent circuit model, and thus, it plays an important role in the popularization and application of the aeronautical lithium-ion battery pack.

H2S Adsorption Characteristics of KOH Impregnated Activated Carbons (KOH 첨착 활성탄에서 황화수소의 흡착 특성)

  • Choi, Do-Young;Jang, Seong-Cheol;Gong, Gyeong-Tack;Ahn, Byoung-Sung;Choi, Dae-Ki
    • Applied Chemistry for Engineering
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    • v.17 no.3
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    • pp.280-285
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    • 2006
  • Adsorption characteristics of $H_{2}S$ on KOH impregnated activated carbon were evaluated using dynamic adsorption method in a fixed bed. The pore properties, including BET's specific surface area, pore volume, pore size distribution, and mean pore diameter of these KOH impregnated activated carbons, were characterized from $N_{2}$ adsorption/desorption isotherms. Adsorption equilibrium data were correlated with Langmuir and Freundlich isotherms. The adsorption of $H_{2}S$ onto the KOH impregnated activated carbon is better fitted by the Langmuir isotherm. An increase in the content of oxygen affects the performance of KOH impregnated activated carbon to the greatest extent.

Pure and Binary Mixture Gases Adsorption Equilibria of Hydrogen/Methane/Ethylene on Activated Carbon (활성탄에서의 H2/CH4/C2H4 순수 기체와 이성분 혼합기체의 흡착평형)

  • Jeong, Byung-Man;Kang, Seok-Hyun;Choi, Hyun-Woo;Lee, Chang-Ha;Lee, Byung-Kwon;Choi, Dae-Ki
    • Korean Chemical Engineering Research
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    • v.43 no.3
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    • pp.371-379
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    • 2005
  • Adsorption equilibria of the gases $H_2$, $CH_4$, and $C_2H_4$ and their binary mixtures on activated carbon (Calgon co.) have been measured by static volumetric method in the pressure range of 0 to 18 atm at temperatures of 293.15, 303.15, and 313.15 K. From the parameters obtained from single component adsorption isotherm, multi-component adsorption equilibria could be predicted and compared with experimental data. The binary experimental data were applied to four models : extended Langmuir, extended Langmuir-Freundlich, Ideal Adsorbed Solution theory (IAST), and Vacancy Solution Model (VSM). The models were found to describe the experimental data with a reasonable accuracy. Extended L-F model predicts equilibria of mixture better than any other model.