• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.2
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• pp.472-477
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• 2017

Oil spills cause a lot of damage to the environment. Oil destroys the water environment and ecosystem in a very short period of time once they are contaminated by it, it takes a lot of time to recover from the contamination and the cleaning process is very difficult. Therefore, oil detectors are greatly needed as they can monitor any oil spills over the sea, rivers, and lakes. There are two kinds of technology available for detecting oil, viz. the contact and non-contact types. The former is based on the use of the conductivity, capacitance and microwaves, while the latter employs infrared, UV, laser, optic and radar technologies. As there are also various hurdles in the measuring of oil on water, such as the presence of waves, refraction of light, temperature and saltiness, it is imperative to select the right oil detector which is appropriate for the specific environment. In this study, a contact type oil detector is developed, which can be used in oil related industries, such as refineries, petrochemical companies, and power generation stations. The detector is made up of the sensor module, which floats on the water, and the controller which processes the signal coming from the sensor module and displays it. It is designed in such a way that the existence of oil is detected through the sensor and the change in the permittivity is observed to determine the volume and type of spilled oil.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.506-512
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• 2018

The fine dust generated in the home and restaurant business occupies a low ratio of about 4% of the total fine dust emissions. However, at the foodservice business, the rate of change of the pollutant concentration is very high, so that the temporary fine dust concentration can be measured up to 60 times. The pollutants generated from non-industrial combustion plants consist of particulate fine dust and gaseous organic compounds. To remove these pollutants, cleaning dust collection system, which is an effective system for simultaneous removal of gaseous and particulate matter, is applied. This is a method of increasing the probability of diffusion capture of the Brownian motion by pressurized liquid injection method using the atomizing nozzle. The dust removal efficiency of the fine dust collecting system was analyzed by nozzle spraying air pressure condition and angle using the manufactured fine dust removing system. As a result, it was confirmed that the efficiency of removal of fine dust and gaseous organic compounds was more than 90%. The developed system is expected to be highly usable in the future because it can remove particulate dust from the existing plant hood system without any installation cost.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.31 no.6
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• pp.276-281
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• 2021

In order to manufacture a semiconductor circuit, etching, cleaning, and deposition processes are repeated. During these processes, the inside of the processing chamber is exposed to corrosive plasma. Therefore, the coating of the inner wall of the semiconductor equipment with a plasma-resistant material has been attempted to minimize the etching of the coating and particle contaminant generation. In this study, we synthesized yttrium oxyfluoride (YOF) powder by a solid-state reaction using Y₂O₃ and YF₃ as raw materials. Mixing ratio of the Y₂O₃ and YF₃ was varied from 1.0:1.0 to 1.0:1.6. Effects of the mixing ratio on crystal structure and microstructure of the synthesized YOF powder were investigated using XRD and FE-SEM. The synthesized YOF powder was successfully applied to plasma spray coating process on Al substrate.

• Clean Technology
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• v.30 no.2
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• pp.94-104
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• 2024

Remanufacturing re-commercializes a used product to achieve an equal or higher performance level than the original product by disassembling, cleaning, inspecting, repairing, reconditioning, and reassembling the used product. The remanufacturing industry is a key industry necessary to realize carbon neutrality by 2050. This study uses life cycle assessment to analyze the resource reduction and greenhouse gas reduction effects with and without considering the avoided effect for an injector, which is an automobile part that is actively being remanufactured. The results of this study showed that the resource reduction effect and greenhouse gas reduction effect induced by injector remanufacturing were reduced by 95.30% and 93.88%, respectively, based on one unit without considering the avoided effect. However, when considering the avoided effect, which in this case is the environmental impact of not disposing of the used injector and not having to use natural resources to manufacture a new injector because the used injector was reused during remanufacturing, the resource reduction effect and greenhouse gas reduction effect were 190.91% and 188.33%, respectively. The results of this study are expected to be used in the future to evaluate the amount of environmental impact reduction while considering the avoided effect during remanufacturing and to help develop research methodology for remanufacturing.

• Journal of Animal Environmental Science
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• v.2 no.1
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• pp.27-39
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• 1996

A survey was conducted for dairy farmer to estimate the optimum number of machine and equipment in 1994. Labor hours, operation costs and operation methods for each dairy processing were investigated and analyzed for the farmers to find the expected numbers of machine and equipment on the basis of the desired farm scale. And also, the estimated models were compared and analyzed with the conventional models which more than half dairy farmers used bucket milker in tie stall barn. Some of the results are as follows : 1. Analysis results of conventional model showed that a dairy farm could raise to 15 heads of dairy cow with family labor of 1.5 men, labor hours of 2, 700 in you and total operation costs of 734 thousand won per head. 2. The result, used in conjunction with minimum operation costs in tie stall barn, showed that 28 dairy cows could be raised by using concentrates feeding by hoppers, water supply by water cups, milking by pipeline milker, and manure cleaning by barn cleaner with total operation costs of 520 thousands won per head. 3. The total operation costs of a loose barn system is higher than those of tie stall barn system to raise about 30 heads. For the loose barn system, the herringbone parlour was used for milking, concentrate feeding by automatic concentrate feeder, water supply by thermal insulation feeder, and manure cleaning by scraper with total operation costs of 582 thousands won per head every year.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.1
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• pp.51-57
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• 2014

Purpose: The present study was conducted to establish the experimental condition for the proper evaluation of protein removal efficacy when developing protein removal agents. Its protein removal efficacy was further analyzed and compared with the result from protein removal efficacy against protein deposition on contact lens to suggest the evaluation method for efficacy of protein removal agents. Methods: Protein digestibility assay presented in the Korean pharmacopoeia was selected to establish the evaluation method for efficacy of papain, pancreatin, subtilisin A and protease itself as a ingredient and protein removal tablets or solution containing those enzymes and find a suitable test conditions. Furthermore, the cleaning efficacy of commercially available protein removal tablets and solution on balafilcon A lens deposited with protein artificially was measured and the correlation between two evaluation methods was further analyzed. Results: When pancreatin itself and the product containing pancreatin was evaluated by protein digestibility assay, both reached 28 IU/mg, the standard value of protein digestibility suggested by the Korean pharmacopoeia. In case of protease and subtilisin A tested with trichloroacetic acid B solution, both of them met the enzyme activity level proposed by the manufacturers when they were evaluated by protein digestibility assay however, papain and subtilisin A tested with trichloroacetic acid A solution were not reached the enzyme activity level. Among protein removal agents, three products except a product containing pancreatin did not meet the enzyme activity value specified by the manufacturer when they were evaluated by protein digestibility assay. However, actual protein removal efficacy of three products except a papain-containing product on the lens was greater than 90% protein removal. In the case of papain-containing protein removal product, its effect was not measured by protein digestibility assay however, its actual protein removal efficacy on the lens reached 73.72%. Conclusions: From the results, it was confirmed that the efficacy of protein removal agents for contact lens should be evaluated by different method according to the type of proteolytic enzyme contained. That is, the protein removal agents containing pancreatin, protease and subtilisin A can be evaluated by protein digestibility assay and protein removal efficiency evaluation and the products containing papain can be effectively evaluated by only the evaluation method for protein removal efficiency employing the lens.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.3
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• pp.155-163
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• 2017

Membrane filtration has become more popular in drinking water treatment recently, since the filtration can control not only particulate matters but also pathogenic microorganisms such as giardia and cryptosporidium very effectively. Pilot-scale ($120m^3/d$ of treatment capacity) and test-bed ($25,000m^3/d$ of treatment capacity) microfiltration experiments were conducted to find optimum operating mode and the critical flux. Optimum operating mode of pilot-test was assessed as inflow 1.0 min, filtration 36.5 min, air backwash 0.9 min, backwash 1.0 min and outflow 1.0 min with 50 LMH ($L/min{\cdot}m3^$) of critical flux. Critical Flux was calculated to be $50L/m^2-h$ (within TMP 0.5 bar) based on the increase formula of the transmembrane pressure difference according to the change of time at Flux 20, 40, 56 and 62 LMH in pilot operation. Chemical cleaning was first acid washed twice, and alkali washing was performed secondarily, and a recovery rate of 95% was obtained in the test-bed plant. The results of operating under these appropriate conditions are as follows. Turbidity of treated water were 0.028, 0.024, 0.026 and 0.028 NTU in spring, summer, autumn and winter time, respectively. Microfiltration has superior treatment capability and performance characteristics in removing suspended solids and colloidal materials, which are the main cause of turbidity and important carrier of metal elements, and it has shown great potential in being an economically substitute to traditional processes (sand filtration).

• Applied Chemistry for Engineering
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• v.10 no.1
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• pp.154-159
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• 1999

EDTA (ethylenediaminetetraacetic acid), a chelating agent is most widely used in industrial applications, especially for cleaning of metals in water, frequently prohibits metal removal from water in conventional water treatment technologies. It could be easier to remove aqueous metal ions by the breakdown of DETA complexed bonds first. This study investigated the availability of $TiO_2$ photo-catalysis for the aqueous phase oxidation of Cu(II)-EDTA, under an aerobic condition at $20^{\circ}C$ with $TiO_2$ (Degussa P-25) and 1.79mM of Cu(II)-EDTA. When $TiO_2$ loading was 2.0 g/L, the photo-catalytic oxidation of Cu(II)-EDTA was maximal. The tendency of EDTA adsorption onto the catalyst surface was affected by $TiO_2$ surface charge, and the oxidation rate of Cu(II)-EDTA by photo-catalysis was shown to be dependent upon the tendency of EDTA adsorption before photo-irradiation.

• Journal of Animal Environmental Science
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• v.14 no.2
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• pp.75-80
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• 2008

High concentration of $NH_3$, $CO_2$, and lots of dust are found in modern densely raising stall system, as results, they provide a negative influence on animal and lamer health, and production ability. Therefore, it is necessary to keep clean the inside of stall air to increase the productivity. A wet type air cleaner has been developed to clean the stall air. The work principle is that the inside air are sucked through the fan, and the rotating discs make a water into a fineness spray and blows into the stall. The spray can take the dust, $NH_3$, and odor from the stall inside air and give back to the circulating water, which can be refreshed in 2 hours interval. In the Present study, we measured the $NH_3$, dust, odor, temperature and humidity in a swine stall that were installed two wet air cleaners with 700 fattening swine with on-mode and off-mode of wet air cleaners. In fall, the concentrations of $NH_3$ in off-mode stall were maximum 24 ppm and minimum 16 prm, and the average was 18.2 ppm. However in on-mode stall the $NH_3$ concentrations were maximum 7ppm and minimum 1ppm, and the average was 2.7ppm. The concentration of $NH_3$ in on-mode was 74% lower than off-mode stall. Odor was measured by olfactometer. In the off-mode stall, the odor unit was 3,800 OU/$m^3$, but in the on-mode stall the odor unit was 2,100 OU/$m^3$ Odor removal efficiency was about 45% in on-mode stall. The dust measure was divided into 3 categories, $PM_{10}$, $PM_{2.5}$ and $PM_{1.0}$. Whereas the $PM_{10}$ showed no significant differences between the tests, $PM_{2.5}$ and $PM_{1.0}$ in the fine particle range reduced remarkably in the on-mode.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.7
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• pp.854-867
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• 2014

In the circumstance that high oil price state is continued over the world, the investment in crude oil development by oil major is a trend of increasing. Recently the number of delivered drill-ship for 5 years has been sharply increased all over the world and about twice than that of past 30 years. As addition to the increase of the drill-ship demand, the operation of drill-ships which is delivered recently is about 3,000 meters, ultra deep sea, on average and the work area is expending. Accordingly the drilling system including the size and length of pipe for drilling has been bigger and bigger and the power supply equipment for operation system also has large capacity. Unlike merchant vessel, high power and high voltage of diesel generators are required for drill-ship for which the demand for V-type 320 bore of diesel generator has increased. It is on the raised that the importance of lubrication oil cleaning for diesel generator on drill-ship which has longer time for construction, and also long term low load operation is unavoidable during commissioning of equipments. Recently it was reported that engine crankpin was damaged due to the hard contact caused by the abnormal wear down(Cam wear) on crankpin and bearing. The same pattern of wear down was found through the inspection on series vessels and the other vessel under commissioning. The purpose of this paper is to analyze of the wear mechanism based on the observation and theories and objective research from actual cases and to prepare the counter measures to avoid foreseeable damage when the lubricating oil is not properly cleaned.