• Resources Recycling
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• v.26 no.3
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• pp.47-52
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• 2017

The concentrate of lepidolite, being treated by heavy medium separation (HMS), was ground with calcium sulphate hemihydrate (CSH, $CaSO_4{\cdot}1/2H_2O$) to investigate the mechanochemical effect for the Li leachability in water. This leachability increased, dramatically through the intensive grinding for the mixture, concentrate and CSH. The leachability of Li was improved from 4.48% to 93.5%. The grinding of the mixture destructed the crystal structure of the concentrate, and it might be formed to new compounds. As the result, Li in the concentrate can be extracted by water leaching at room temperature.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.9
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• pp.1082-1087
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• 2019

Video Incident Detection System is a detection system for the purpose of detection of an emergency in an unexpected situation such as a pedestrian in a tunnel, a falling object, a stationary vehicle, a reverse run, and a fire(smoke and flame). In recent years, the importance of the city center has been emphasized by the construction of underpasses in great depth underground space. Therefore, in order to apply Video Incident Detection System to a Double Deck Tunnel, it was developed to reflect the design characteristics of the Double Deck Tunnel. and In this paper especially, the fire detection technology, which is not it is difficult to apply to the Double Deck Tunnel environment because it is not supported on existing Video Incident Detection System or has a fail detect, we propose fire detection using color image analysis, silhouette spread, and statistical properties, It is verified through a real fire test in a double deck tunnel test bed environment.

• Journal of Powder Materials
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• v.29 no.4
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• pp.283-290
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• 2022

A Cu-15Ag-5P filler metal (BCuP-5) is fabricated on a Ag substrate using a high-velocity oxygen fuel (HVOF) thermal spray process, followed by post-heat treatment (300℃ for 1 h and 400℃ for 1 h) of the HVOF coating layers to control its microstructure and mechanical properties. Additionally, the microstructure and mechanical properties are evaluated according to the post-heat treatment conditions. The porosity of the heat-treated coating layers are significantly reduced to less than half those of the as-sprayed coating layer, and the pore shape changes to a spherical shape. The constituent phases of the coating layers are Cu, Ag, and Cu-Ag-Cu3P eutectic, which is identical to the initial powder feedstock. A more uniform microstructure is obtained as the heat-treatment temperature increases. The hardness of the coating layer is 154.6 Hv (as-sprayed), 161.2 Hv (300℃ for 1 h), and 167.0 Hv (400℃ for 1 h), which increases with increasing heat-treatment temperature, and is 2.35 times higher than that of the conventional cast alloy. As a result of the pull-out test, loss or separation of the coating layer rarely occurs in the heat-treated coating layer.

• Korean Journal of Food Science and Technology
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• v.41 no.2
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• pp.203-209
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• 2009

This study was conducted to evaluate the effects of the salts fortified with Hizikia component on blood pressure and mineral composition in spontaneously hypertensive rats (SHR/NCrj) and normotensive rats (WKY/NCrj). The two species rats were assigned to three groups and were fed with drinking water to which Hizikia salts were added for 6 weeks. The final blood pressures (BP) among groups of SHR were increased to 12, 4, and 21%, respectively. In terms of urine and fecal minerals, the $Na^+$ contents in two species were significantly higher in the control than in the salt groups, and vice versa with regard to the $ K^+$ contents. The amount of excretion mineral was higher in urine than in feces. The $Na^+$, $Ca^{++}$ and $Mg^{++}$ contents of the liver in SHR were higher in the control than in the salt groups (p<0.05). The $Na^+$ content of the kidney in SHR was higher in the control than in the salt groups, but the content was shown an opposite trend in WKY. The $K^+$ contents were higher in the low salt group (p<0.05). These results may indicate that the salts fortified with the Hizikia component may be useful in lowering systolic blood pressure owing to the maintenance of positive mineral metabolism.

• 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.

• Journal of Food Hygiene and Safety
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• v.31 no.6
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• pp.451-457
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• 2016

The purpose of this study was to determine the antimicrobial effects of $ClO_2$ gas on pathogenic E. coli and Salmonella spp. colonizing on the fruit surface of strawberries for export. Factorial design was employed to treat strawberries inoculated with pathogenic E. coli or Salmonella spp. with a combination of $ClO_2$ gas concentrations (10, 20, 30, 40, and 50 ppmv), RH (50, 70, and 90%), and treatment time (0, 5, 10, 20, and 30 min). Interaction between the factors was observed to note that the reduced levels of microbial population were the highest when RH is set at 90% with gas concentration- and treatment time-dependent manner. With RH and gas concentration fixed at 90% and 50 ppmv, the populations of E. coli and Salmonella spp. decreased by 2.07 and 2.28 log CFU/g when treated for 20 min whereas population reduction by 0.5 and 0.7 log CFU/g were observed when treated for 5 min, respectively. The results help establish most effective conditions for $ClO_2$ gas treatment to enhance microbial safety of strawberries for export.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.8
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• pp.492-497
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• 2015

VOCs (Volatile Organic Compounds) are generally generated in the painting process, or at the company and laundry where use organic solvents. The VOCs consist of various hydrocarbons and has low calorific value due to its dilution with atmospheric air. Therefore, the VOCs are difficult to burn by a conventional fuel combustor. In this study, a novel plasma dump combustor was proposed for the treatment of low calorific VOC gases. This combustor was designed a combination of the characteristics in a plasma burner, a dump combustor and a 3D matrix burner. The combustor has good structure for maintaining enough residence time and reaction temperature for stable flame formation and VOC destruction. For investigating the performance characteristics of the plasma dump combustor, an experiment was achieved for VOC feed rate, VOC injector position, etc. Toluene was used as a surrogate of VOC. The novel combustor gave better performance than a conventional combustor, showing that VOC destruction rate and energy efficiency were 89.64% and 12.27 kg/kWh respectively, at feeding rate of 450 L/min of VOC of 3,000 ppm of toluene concentration.

• Applied Microscopy
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• v.38 no.3
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• pp.259-264
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• 2008

The stabilized $ClO_2$ gas has been used for many years by the food industry as a strong oxidizing and sanitizing agent that has broad and high biocidal effectiveness. Therefore, "stabilized $ClO_2$" gas may be used in fields of disinfectant and sterilization. But, there have been few studies on the decomposition-inhibition effect of stabilized $ClO_2$ gas with passage of time. The main purpose of this study was to examine the decomposition-inhibition effect of stabilized $ClO_2$ gas and the morphological change of kidney by measuring of the light and electron microscope. Sprague-Dawley (SD) rats weighting from 230 gm to 250 gm were used as experimental animals. Under ether anesthesia, the right kidney of rat was obtained. Put each sample in $37^{\circ}C$ and humidity $80{\pm}5%$ incubator, we obtained each sample after 0 day, 1 day, 2 days, 3 days, 4 days and 5 days. We proceeded the observation of light and electron microscope. The results obtained in this study reveal that stabilized $ClO_2$ gas is an effective decomposition inhibitor until 2 days that was conducted at $37^{\circ}C$ and humidity $80{\pm}5%$ conditions.

• Weed & Turfgrass Science
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• v.3 no.3
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• pp.215-220
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• 2014

This study was conducted to evaluate potential weed control in organic farming field using false seedbed and stale seedbed techniques. The experiment was conducted in open upland fields during spring and fall crop seasons. The false seedbed was prepared before 2-4 weeks of crop culture and was treated with shallow tillage or flame weeding before transplanting. The weed suppression rates of false seedbed treatment in the spring crop experiments for Chinese cabbage, soybean, hot pepper and corn were 65-73%, 50-55%, 9-55% and 8-33%, respectively. According to crop growth and yield in this experiment, the false seedbed technique has some potential weed control for Chinese cabbage, soybean and corn. The weed suppression rates of stale seedbed treatments in the fall crop experiments for Chinese cabbage, spinach and carrot were 18-39%, 40-77% and 37-38%, respectively. Weed control efficacy of the stale seedbed in this study was lower, when compared with false seedbed.

• Journal of Food Hygiene and Safety
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• v.38 no.6
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• pp.508-516
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• 2023

The consumption of enoki mushrooms has been associated with cases of listeriosis produced by Listeria monocytogenes, highlighting the significance of sanitizing food-contact surface, such as the velcro used in welding processing of enoki mushrooms, to ensure microbial safety. We investigated the inhibitory activity of nine chemical disinfectants at regular concentrations against L. monocytogenes isolated from a mushroom farm environment. The bacterial suspension was prepared in phosphate buffered saline and mushroom extract broth and inoculated onto the velcro surface. After inoculation, most disinfectants reduced the initial 8 log CFU/coupon concentration by less than 2 log CFU/coupon during a 5-min treatment. Slightly acidic hypochlorous water showed a reduction of approximately 4 log CFU/coupon when tested for more than 30 min at the maximum allowable concentration of 200 mg/L. Sodium hypochlorite solution showed a reduction of approximately 5 log CFU/coupon when used at 100 mg/L for 60 min. Peracetic acid, at the maximum allowable concentration of 300 mg/L, showed the most effective reduction of 5 log CFU/coupon or more when the surface was treated with 37.5 mg/L for 30 min. These results indicate that peracetic acid can be used as the disinfectant strategy to control cross-contamination of L. monocytogenes on the velcro surface of plastic wrappers used in the welding processing of enoki mushrooms.