• Journal of Environmental Impact Assessment
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• v.23 no.6
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• pp.492-504
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• 2014

Feral pigeon (Columba livia) has been known as a good indicator for accumulations of chemical pollutants in urban areas. However, it is against the animal rights to kill the indicator species in order to monitor pollutants accumulations in wild birds. Eggs and feathers of birds, therefore, have been used as non-invasive monitoring materials. Even though eggs are a good indicator for accumulations of lipophilic pollutants, but unsuitable for some heavy metals such as lead and cadmium because bird's ovary builds a sort of barrier to inhibit higher accumulations of some heavy metals in the eggs. Therefore, feathers instead of eggs have been used as a non-invasive indicator for accumulations of heavy metals. However, there are few studies of heavy metal accumulations of feral pigeon in Korea. In this study, we characterized the characteristics of heavy metal accumulations of feathers in relation to internal organs (bloods, viscera and bones) in feral pigeons between two sites (Hangang Park representing urban area and Hampyeong Park for rural area). The samples from the Hangang Park showed significantly higher lead (Pb) concentrations in the blood, liver and bone than those from Hampyeong Park. The Pb concentration in the feathers was also significantly higher at Hangang Park than at Hampyeong Park. The analytical result for the breast, wing and tail feathers, and the internal organs (blood, lung, liver, kidney and bone) indicated that the Pb concentrations in the feathers were significantly positively correlated with the levels in the kidney and bone. Overall, feathers of feral pigeon may be candidate for bioindicator to monitor for Pb accumulations in urban areas.

• Tuberculosis and Respiratory Diseases
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• v.56 no.6
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• pp.670-676
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• 2004

Chemical pneumonitis is caused by the inhalation of noxious chemical substances and is a cause of occupational lung disease. Nitric acid, which is a one of the common air pollutants and a potential oxidant for refining and cleansing of metals, has a chance for occupational and environmental exposure. A 52-year-old man visited our hospital due to coughing and dyspnea after the inhalation of nitric acid fumes at his workplace. He had conditions of tachypnea (respiratory rate 26 /min) and hypoxemia ($PaO_2$ 42.6 mmHg, $SaO_2$ 80.2% in room air) in our emergency department. The chest radiographs showed diffuse interstitial infiltrates and ground glass opacity in both lungs. The patient made improvements in clinical symptoms and chest radiography after being given a supply of oxygen, antibiotics, and bronchodilator therapy without systemic glucocorticoid therapy. On his follow up visit after 4 weeks, he showed no symptoms and sequelae, and the pulmonary function test showed a normal pulmonary function.

• Korean Journal of Optics and Photonics
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• v.29 no.3
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• pp.119-125
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• 2018

Hydrogen gas is an important and promising energy resource that has no emissions of pollutants during power generation. However, hydrogen gas is very dangerous because it is colorless, odorless, highly flammable, and explosive at low concentration. Conventional techniques for hydrogen gas detection are very difficult for measuring the hydrogen gas distribution at long distances, because they sample the gas to measure its concentration. Raman lidar is one of the techniques for remotely detecting hydrogen gas and measuring the range of the hydrogen gas distribution. A Raman lidar system with an on-axis optical receiver was developed to improve the range of hydrogen gas detection at long distance. To verify the accuracy and improvement in the range of detecting the hydrogen gas, experiments measuring the hydrogen gas concentration are carried out using the developed on-axis Raman lidar system and a gas chamber, to prevent explosion of the hydrogen gas. As a result, our developed on-axis Raman lidar system can measure a minimum hydrogen gas concentration of 0.66 volume percent at a distance of 50 m.

• Korean Chemical Engineering Research
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• v.48 no.2
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• pp.268-274
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• 2010

Emission of heavy metals as hazardous air pollutants has been focused with tightening regulatory limits due to their hazardousness. Measurements and characteristic investigations of heavy metals emitted from a commercial power plant burning anthracite coal have been carried out. The plant consists of a circulating fluidized bed combustor, a cyclone, a boiler and an electrostatic precipitator(ESP) in series. Dust and gaseous samples were collected to measure main heavy metals including gaseous mercury before ESP and at stack. Dust emissions as total particulate matter (TPM), PM-10 and PM-2.5 at inlet of ESP were very high with 23,274, 9,555 and $7,790mg/Sm^3$, respectively, as expected, which is much higher than those from pulverized coal power plants. However TPM at stack was less than $0.16mg/Sm^3$, due to high dust removal efficiency by ESP. Similarly heavy metals emission showed high collection efficiency across ESP. From particle size distribution and metal enrichment in sizes, several metal concentrations could be correlated with particle size showing more enrichment in smaller particles. Mercury unlike other solid metals behaved differently by emitting as gaseous state due to high volatility. Removal of mercury was quite less than other metals due to it's volatility, which was 68% only. Across ESP, speciation change of mercury from elemental to oxidized was clearly shown so that elemental mercury was half of total mercury at stack unlike other coal power plants which equipped wet a scrubber.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.6
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• pp.123-132
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• 2012

Gas sensors has been used very differently that depending on following purposes; Automotive (exhaust gas, fuel mixture gas, oxygen, particulates), agriculture / food industry (fresh, stored, CO2, humidity, NH3, nitrogen oxide gas, organic gas, toxic gas emitted from pesticides and insecticides), industrial / medical (chemical gas, hydrogen, oxygen and toxic gases), military (chemical weapon), environmental measurements (CO and other air pollution consisting of sulfur and nitrogen gas), residential (LNG, LPG, butane, indoor air, humidity). The types of industrial toxic substances are known about 700 species and many of these exist in gaseous form under normal conditions. he multi-gas detection sensors will be developed for casualties that detect the most important and find easy three kinds of gases in marine plant; carbon dioxide(CO2), carbon(CO), ammonia(NH3). Package block consists of gas sensing device minor ingredient, rf front end, zigbee chip. Develope interworking technology between the sensor and zigbee chip inside a package. Conduct a performance test through test jig about prototype zigbee sensor module with rf output power and unwanted emission test. This research task available early address when poisonous gas leaked from large industrial site and contribution for workers' safety at the enclosed space.

• Clean Technology
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• v.28 no.4
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• pp.285-292
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• 2022

Adsorption tower systems based on activated carbon adsorption towers have mainly been employed to reduce the emission of volatile organic compounds (VOCs), a major cause of air pollution. However, the activated carbon currently used in these systems has a short lifespan and thus requires frequent replacement. An approach to overcome this shortcoming could be to develop metal oxide photocatalysis-activated carbon composites capable of degrading VOCs by simultaneously utilizing photocatalytic activation and powerful adsorption by activated carbon. TiO₂ has primarily been used as a metal oxide photocatalyst, but it has low economic efficiency due to its high cost. In this study, ZnO particles were synthesized as a photocatalyst due to their relatively low cost. Silver nanoparticles (Ag NPs) were deposited on the ZnO surface to compensate for the photocatalytic deactivation that arises from the wide band gap of ZnO. A microfluidic process was used to synthesize ZnO particles and Ag NPs in separate reactors and the solutions were continuously supplied with a pack bed reactor loaded with activated carbon powder. This microfluidic-assisted pack bed reactor efficiently prepared a Ag-ZnO-activated carbon composite for VOC removal. Analysis confirmed that Ag-ZnO photocatalytic particles were successfully deposited on the surface of the activated carbon. Conducting a toluene gasbag test and adsorption breakpoint test demonstrated that the composite had a more efficient removal performance than pure activated carbon. The process proposed in this study efficiently produces photocatalysis-activated carbon composites and may offer the potential for scalable production of VOC removal composites.

• Clean Technology
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• v.26 no.2
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• pp.102-108
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• 2020

In recent years, packed column has been widely used in separation processes, such as absorption, desorption, distillation, and extraction, in the petrochemical, fine chemistry, and environmental industries. Packed column is used as a contacting facility for gas-liquid and liquid-liquid systems filled with random packed materials in the column. Packed column has various advantages such as low pressure drop, economical efficiency, thermally sensitive liquids, easy repairing restoration, and noxious gas treatment. The performance of a packed column is highly dependent on the maintenance of good gas and liquid distribution throughout a packed bed; thus, this is an important consideration in a design of packed column. In this study, hydraulic pressure drop, hold-up as a function of liquid load, and mass transfer in the air, air/water, and air-NH₃/water systems were studied to find the geometrical characteristic for raschig super-ring experiment dry pressure drop. Based on the results, design factors and operating conditions to handle noxious gases were obtained. The dry pressure drop of the random packing raschig super-ring was linearly increased as a function of gas capacity factor with various liquid loads in the Air/Water system. This result is lower than that of 35 mm Pall-ring, which is most commonly used in the industrial field. Also, it can be found that the hydraulic pressure drop of raschig super-ring is consistently increased by gas capacity factor with various liquid loads. When gas capacity factor with various liquid loads is increased from 1.855 to 2.323 kg^-1/2 m^-1/2 S^-1, hydraulic pressure drop increases around 17%. Finally, the liquid hold-up related to packing volume, which is a parameter of specific liquid load depending on gas capacity factor, shows consistent increase by around 3.84 kg^-1/2 m^-1/2 S^-1 of the gas capacity factor. However, liquid hold-up significantly increases above it.

• Analytical Science and Technology
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• v.19 no.3
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• pp.263-271
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• 2006

The levels of total PCBs, Co-PCBs and PCDD/Fs in the transformer insulation oil samples obtained using GC/ECD and HRGC/HRMS were ranged from N.D. to 77.3 ppm, from 0.0863 to 2.49 ppm and from N.D. to 0.00241 ppm, respectively. In terms of WHO-TEQ values, Co-PCBs and PCDD/Fs were ranged from 23.3 to 600 pgTEQ/g and from N.D. to 128 pgTEQ/g, respectively (${\Sigma}Co$-PCBs+PCDD/Fs concentration was calculated 24.4~728 pgTEQ/g). Although, the contribution of PCDD/Fs was below 12% in total TEQ concentration, it is suggested contamination of PCDD/Fs in transformer insulation oils. Among 10 samples, 4 samples showed higher concentration than 2 ppm (specific waste criterion of Korea) and Aroclor 1242, 1248, 1254 and 1260 was detected in samples as a single or mixture of Aroclor. It was shown reliable relationship between concentration of Co-PCBs and those of PCDD/Fs (p<0.003), however, was not shown between production year of transformer and concentration of PCBs. The distribution pattern of Co-PCB congeners showed that the ratios of mono-ortho substituted congeners were higher than non-ortho substituted congeners. Among that, PCB-118 congener was predominant. In addition, the OCDD congener was predominated in PCDD/Fs congeners as above 53%. Moreover, the congener pattern of Co-PCBs was similar to that of Aroclor as well as ambient air, which suggested that PCBs volatilization from transformer insulation oil affected the pattern of Co-PCBs in ambient air.

• Korean Journal of Environmental Agriculture
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• v.17 no.4
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• pp.291-295
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• 1998

Changes of chemical components and natural supplies by precipitation at agricultural zone in Chinan area of Chonbuk province from May 1, 1997 to April 30, 1998 were investigated. pH of precipitation ranged $6.44{\sim}7.24$ and EC showed $14.23{\sim}30.67{\mu}S/cm$. The $total{\sim}N$, NH4-N and NO3-N were $1.43{\sim}10.14$, $0.57{\sim}4.39$, and $0.18{\sim}1.69㎎/L$ respectively. The content of total-P showed $0.015{\sim}0.087㎎/L$ but ortho-P was not detected. The content of suspended solid, $Ca^{++}$, $Mg^{++}$, $Na^+$ and $K^+$ showed $3.6{\sim}15.3$, $0.37{\sim}1.66$, $0.17{\sim}0.52$, $0.22{\sim}0.87$, and $0.17{\sim}0.58㎎/L$. The content of SO42- and Cl- showed $3.37{\sim}014.47㎎/L$ and $1.02{\sim}7.24㎎/L$ respectively. Only Cu and Zn of heavy metals were detected $0{\sim}0.019㎎/L$ and $0.009{\sim}0.098㎎/L$ but Cd, Cu, Ni and Cr were not detected. Natural supplies of chemical components were 39.48㎏/ha/yr of total-N, 21.82㎏/ha/yr of $NH_4-N$, 6.90㎏/ha/yr of $NO_3-N$ and 0.68㎏/ha/yr of total-P. Also $Ca^{++}$, $Mg^{++}$, $Na^+$, $K^+$, $SO_4^{2-}$ and $Cl^-$ were supplied 14.46, 5.00, 7.26, 5.46, 98.76 and 31.16㎏/ha/yr respectively. Only of heavy metals were supplied 0.024㎏/ha/yr of Cu and 0.044㎏/㏊/yr of Zn.

• Clean Technology
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• v.28 no.2
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• pp.131-137
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• 2022

The semiconductor process currently emits various by-products and unused gases. Emissions containing pollutants are generally classified into categories such as organic, acid, alkali, thermal, and cabinet exhaust. They are discharged after treatment in an atmospheric prevention facility suitable for each exhaust type. The main components of organic exhaust are volatile organic compounds (VOC), which is a generic term for oxygen-containing hydrocarbons, sulfur-containing hydrocarbons, and volatile hydrocarbons, while the main components of alkali exhaust include ammonia and tetramethylammonium hydroxide. The purpose of this study was to determine the combustion characteristics and analyze the NO_X reduction rate by maintaining a direct combustion and temperature to process organic and alkaline exhaust gases simultaneously. Acetone, isopropyl alcohol (IPA), and propylene glycol methyl ether acetate (PGMEA) were used as VOCs and ammonia was used as an alkali exhaust material. Independent and VOC-ammonia mixture combustion tests were conducted for each material. The combustion tests for the VOCs confirmed that complete combustion occurred at an equivalence ratio of 1.4. In the ammonia combustion test, the NO_X concentration decreased at a lower equivalence ratio. In the co-combustion of VOC and ammonia, NO was dominant in the NO_X emission while NO₂ was detected at approximately 10 ppm. Overall, the concentration of nitrogen oxide decreased due to the activation of the oxidation reaction as the reaction temperature increased. On the other hand, the concentration of carbon dioxide increased. Flameless combustion with an electric heat source achieved successful combustion of VOC and ammonia. This technology is expected to have advantages in cost and compactness compared to existing organic and alkaline treatment systems applied separately.