• Nuclear Engineering and Technology
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• v.54 no.11
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• pp.4013-4021
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• 2022

A kind of zirconium phosphate mesoporous coordination polymer Zr-EDTMPA was successfully synthesized and characterized using XRD, FTIR, TGA, EA, SEM-EDS, and N₂ sorption-desorption measurements. The prepared Zr-EDTMPA was first employed for the removal of Co(II) from an aqueous solution, and the effects of pH, contact time, temperature, initial Co(II) concentration, reusability, and sorption mechanism were systematically investigated. The results showed that the Zr-EDTMPA is a zirconium phosphate complex formed by the coordination of EDTMPA to Zr in a molar ratio of 1:1. The sorption of Co(II) by Zr-EDTMPA was a pH-dependent, spontaneous and endothermic process, which was better fitted to the pseudo-second-order kinetic model and Langmuir isotherm model. The Zr-EDTMPA was demonstrated to have excellent reusability and presented a high sorption capacity of 73.0 mg·g^-1 for Co(II) at pH 8.0. The sorption mechanism was mainly attributed to the strong coordination between cobalt and the untapped hydroxyl functional groups on Zr-EDTMPA, which was confirmed by XPS spectra. Therefore, as a candidate sorbent with high sorption capacity and excellent reusability, Zr-EDTMPA has a great potential for the removal of Co(II) from aqueous solutions.

• Journal of the Korean Society of Radiology
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• v.9 no.4
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• pp.257-261
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• 2015

Radon is produced after the Uranium-238 and thorium-232 undergone radioactive decay process is a colorless, odorless inert gas is stored in a basement or an enclosed space. Building materials are made by a rock or soil materials. Form of radon gas is introduced into the lungs through the respiratory tract and deposited in the lungs or bronchial Daughter nuclides radon causes lung cancer. In this study, To subject the Constructed Apartment in Gwangju Gwangsan-Gu, the position is closed window and opened window was measured using a measuring instrument for radon. The measured results indicate that the measurement was carried out in concentrations of radon gas measured at Newly Constructed Apartment is low than United states in the radon concentration in air public 4 pCi called radon gas baseline maximum allowable concentrations. The exposure caused by radon concentration of new construction apartment when on the measurement results is expected to be insignificant. However, when radon gas like this is that it accumulates in the body and lungs get damaged due to exposure, such as lung cancer often open the windows to reduce the radon concentration measurements, such as in radiation protection aspects to the ventilation to reduce exposure it is considered necessary.

• Journal of Environmental Science International
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• v.21 no.7
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• pp.815-824
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• 2012

The purpose of this study was to analyze the meteorological characteristics of wintertime high PM10 concentration episodes in Busan. $PM_{10}$ concentration has been reduced for the past four years and recorded near or exceeded 100 ${\mu}g/m^3$ (national standard of $PM_{10}$). High concentration episodes in Busan were 6 case, $PM_{2.5}/PM_{10}$ ratio was 0.36~0.39(mean 0.55). High $PM_{10}$ concentration occurred during higher air temperature, more solar radiation and sunshine, lower relative humidity, and smaller cloud amount. Synoptically, it also occurred when Busan was in the center or the edge of anticyclone and when sea breeze intruded. An analysis of upper air sounding showed that high $PM_{10}$ concentration occurred when surface inversion layer and upper subsidence inversion layer existed, and when boundary layer depth and vertical mixing coefficient were low. An analysis of backward trajectory of air mass showed that high $PM_{10}$ concentration was largely affected by long range transport considering that it occurs when air mass is intruded from China.

• Journal of Radiation Protection and Research
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• v.26 no.4
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• pp.399-408
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• 2001

The variation characteristics of radon concentration, equilibrium equivalent concentration and equilibrium factor in some houses and laboratory buildings have been studied. The variation of equilibrium factor and the unattached fraction of radon progeny with ventilation condition have been also estimated. The averages of radon concentration, equilibrium equivalent concentration and equilibrium factor were $30\;Bq\;m^{-3},\;19.6\;Bq\;m^{-3}$ and 0.65 in seven houses, while $55.0\;Bq\;m^{-3},\;31.9\;Bq\;m^{-3}$ and 0.58 in three laboratory buildings, respectively. The diurnal variation of radon concentration, equilibrium equivalent concentration and equilibrium factor in indoor showed a typical pattern that the radon concentration, equilibrium equivalent concentration and equilibrium factor increased at dawn and morning, while decreased at midday and evening. While the equilibrium factor rate deceased in the indoor environment which was well ventilated, the unattached traction of radon progeny increased. The equilibrium factor was in proportion to air pressure and humidity of indoor, whereas in Inverse proportion to temperature.

• Journal of Radiation Protection and Research
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• v.46 no.3
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• pp.127-133
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• 2021

Background: Phosphogypsum is material produced as a byproduct in fertilizer industry and is generally used for building materials. This material may contain enhanced radium-226 (²²⁶Ra) activity concentration compared to its natural concentration that may lead to indoor radon accumulation. Therefore, an accurate measurement method is proposed in this study to determine ²²⁶Ra activity concentration in phosphogypsum sample, considering the potential radon leakage from the sample container. Materials and Methods: The International Atomic Energy Agency (IAEA) phosphogypsum reference material was used as a sample in this study. High-purity germanium (HPGe) gamma spectrometry was used to measure the activity concentration of the ²²⁶Ra decay products, i.e., ²¹⁴Bi and ²¹⁴Pb. Marinelli beakers sealed with three different sealing methods were used as sample containers. Due to the potential leakage of radon from the Marinelli beaker (MB), correction to the activity concentration resulted in gamma spectrometry is needed. Therefore, the leaked fraction of radon escaped from the sample container was calculated and added to the gamma spectrometry measured values. Results and Discussion: Total activity concentration of ²²⁶Ra was determined by summing up the activity concentration from gamma spectrometry measurement and calculated concentration from radon leakage correction method. The results obtained from ²¹⁴Bi peak were 723.4 ± 4.0 Bq·kg^-1 in MB1 and 719.2 ± 3.5 Bq·kg^-1 in MB2 that showed about 5% discrepancy compared to the certified activity. Besides, results obtained from ²¹⁴Pb peak were 741.9 ± 3.6 Bq·kg^-1 in MB1 and 740.1 ± 3.4 Bq·kg^-1 in MB2 that showed about 2% difference compared to the certified activity measurement of ²²⁶Ra concentration activity. Conclusion: The results show that radon leakage correction was calculated with insignificant discrepancy to the certified values and provided improvement to the gamma spectrometry. Therefore, measuring ²²⁶Ra activity concentration in TENORM (technologically enhanced naturally occurring radioactive material) sample using radon leakage correction can be concluded as a convenient and accurate method that can be easily conducted with simple calculation.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.20 no.3
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• pp.203-224
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• 2016

The heat and mass transfer characteristics of the unsteady hydromagnetic natural convection flow with Hall current and Soret effect of an incompressible, viscous, electrically conducting, heat absorbing and optically thin radiating fluid flow past a suddenly started vertical infinite plate through fluid saturated porous medium in a rotating environment are taken into account in this paper. Derivations of exact analytical solutions are aimed under different physical properties. The velocity, concentration and temperature profiles, Sherwood number and Nusselt number are easily examined and discussed via the closed forms obtained. Soret effect and permeability parameter tends to accelerate primary and secondary fluid velocities whereas hall current, radiation and heat absorption have reverse effect on it. Radiation and heat absorption have tendency to enhance rate of heat transfer at the plate. The results obtained here may be further used to verify the validity of obtained numerical solutions for more complicated transient free convection fluid flow problems.

• Journal of Radiation Protection and Research
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• v.12 no.2
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• pp.9-18
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• 1987

The present study has determined BUN, createinine, c-AMP and $PGE_2$ activities as a clinical signs of radiation toxicity caused by uranylnitrate in rats. The significant increasing of $PGE_2$ concentration in plasma between the administration of uranylnitrate and lead nitrate were shown radiotoxic in nature on the effect of radiation energy. The reduction of PGE activities in plasma in uranylnitrate treated rats after furosemide, aldosterone and glucagone I.P. administration have observed the stimulating effect of uranium excretion into cells.

• Environmental Engineering Research
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• v.25 no.1
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• pp.29-35
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• 2020

The aim of this study was to estimate the microbial metabolic activity of indigenous soil microbes under the radon exposure with different intensity and times in the secured laboratory radon chamber. For this purpose, the soil microbes were collected from radon-contaminated site located in the G county, Korea. Thereafter, their metabolic activity was determined after the radon exposure of varying radon concentrations of 185, 1,400 and 14,000 Bq/㎥. The average depth variable concentrations of soil radon in the radon-contaminated site were 707, 860 and 1,185 Bq/㎥ from 0, 15, and 30 cm in deep, respectively. Simultaneously, the soil microbial culture was mainly composed of Bacillus sp., Brevibacillus sp., Lysinibacillus sp., and Paenibacillus sp. From the radon exposure test, higher or lower radiation intensities compared to the threshold level attributed the metabolic activity of mixed microbial consortium to be reduced, whereas the moderate radiation intensity (i.e. threshold level) induced it to the pinnacle point. It was decided that radon radiation could instigate the microbial metabolic activity depending on the radon levels while they were exposed, which could consequently address that the certain extent of threshold concentration present in the ecosystem relevant to microbial diversity and population density to be more proliferated.

• Nuclear Engineering and Technology
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• v.41 no.8
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• pp.1101-1108
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• 2009

The ocean contains around eighty elements of the periodic table and uranium is also one among them, with a uniform concentration of 3.3 ppb and a relative abundance factor of 23. With a large coastline, India has a large stake in exploiting the 4 billion tonnes of uranium locked in seawater. The development of radiation grafting techniques, which are useful in incorporating the required functional groups, has led to more efficient adsorbent preparations in various geometrical configurations. Separation based on a polymeric adsorbent is becoming an increasingly popular technique for the extraction of trace heavy metals from seawater. Radiation grafting has provided definite advantages over chemical grafting. Studies related to thermally bonded non woven porous polypropylene fiber sheet substrate characterization and parameters to incorporate specific groups such as acrylonitrile (AN) into polymer back bones have been investigated. The grafted polyacrylonitrile chains were chemically modified to convert acrylonitrile group into an amidoxime group, a chelating group responsible for heavy metal uptake from seawater/brine. The present work has been undertaken to concentrate heavy metal ions from lean solutions from constant potential sources only. A scheme was designed and developed for investigation of the recovery of heavy metal ions such as uranium and vanadium from seawater.

• Applied Chemistry for Engineering
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• v.8 no.1
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• pp.108-113
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• 1997

Decomposition of oxalic acid was studied in nitric acid media by using UV radiations. The UV source is Hg-lamp, emitting $2537{\AA}$ wavelength. Oxalic acid was not decomposed by itself in spite of UV radiation, but in the presence of nitric acid decomposed easily under UV radiation. It is believed that oxygen radical generated from nitrate ion by UV radiation results in the decomposition of oxalic acid. Decomposition rate of oxalic acid reached a maximum in around 0.5M $HNO_3$ and then gradually decreased with nitric acid concentration. The decrease can be also explained to be due to the reaction between oxygen radical and $NO_3{^-}$.