• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.265-270
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• 2001

Nowadays, like any other areas we have asked that the concrete would get more and more properties to increase there performance. So, in this research we are intended to develop the Photocatalytic Concrete which is one of the High Performance Concrete with waste gas reduction and self-cleaning. The fundamental phenomena of the Photocatalytic Concrete were observed by the residue water-weight, SEM, flow and surface hardness(Pencil tester). As a result of this study, the Photocatalytic Concrete used Photocatalytic powder, OPC admixture and other materials can obtain its properties, also photocatalytic efficiency. Last of all, we are convinced of the Photocatalytic Concrete possibility and make an effort to develop its properties added a various study.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.33-36
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• 2009

This study suggests manufacturing and cleaning the feeding system of hydrogen peroxide to use oxidizer of liquid rocket. We established the process of cleaning and passivation in order to minimize the pollution of Hydrogen Peroxide feeding system. And, we verified stability of the manufactured feeding system by leak test & hot test.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2004.04a
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• pp.149-152
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• 2004

Generally the wafer is increased by 300mm. We are desired that the wafer is prevented from pollutions of metal contaminant on surface of wafer. We have to develop new wafer cleaning process of IC Manufacturing that can reduce DI water and chemical by removal of the wafer cleaning process step. Moreover, it is difficult to control temprature and density of chemical in spite of rapidly increasing automation of system. We design smart module controller for new generation of semiconductor wet station with intelligent algorithm using data that is taken by computer simulation for optimal system.

• Journal of Korean Institute of Industrial Engineers
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• v.37 no.4
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• pp.415-420
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• 2011

Snow removal system is named for machinery which manages roads for passing of pedestrians and automobiles when snow is piled up on the road. This paper studies configuration design of snow removal system that has several functions-melting snow in the street without moving it to other place, transferring snow to the melter and cleaning road by spraying water for cleaning road. These sorts of functions are analyzed by function decomposition method of Kirshman and Fadel and, based upon which, machine parts are selected. Layout design would follow functional design to testify if the selected component satisfies space which is allowed by constraints.

• Air Cleaning Technology
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• v.22 no.2
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• pp.40-49
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• 2009

Aluminum thin plate coated with epoxy resin containing about 20wt% brass powder, was applied to fins of heat exchanger. We carried out a series of detailed examinations to evaluate the anti-bacterial performance of the plate and heat exchanger (fan coil unit). In the presence of water or moisture, copper ions which have an anti-bacterial ability eluted from brass powder and showed sufficient effects on many kinds of bacteria. We also evaluated the anti-bacterial performance quantitatively by use of the index API (Anti-bacterial Performance Index) which has already been proposed by authors.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.205.2-205.2
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• 2011

Micro hydraulic turbines take a growing interest because of its small and simple structure as well as high possibility of applying to micro and small hydropower resources. The differential pressure exiting within the city water pipelines can be used efficiently to generate electricity like the energy generated through gravitational potential energy in dams. In order to reduce water pressure at the inlet of water cleaning centers, pressure reducing valves are used widely. Therefore, pressure energy is wasted. Instead of using the pressure reduction valve, a micro counter-rotating hydraulic turbine can be replaced to get energy caused by the large differential pressure found in the city water pipelines. In this study, in order to acquire design data of counter-rotating tubular type micro-turbine, output power, head, and efficiency characteristics due to the diffuser.

• Analytical Science and Technology
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• v.37 no.1
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• pp.1-11
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• 2024

In agricultural households cultivating vegetables and fruits, the use of various pesticides to protect crops from diseases and pests or to control weeds is widely practiced enhancing quality and productivity. However, pesticides can pose a threat to consumer health by remaining on the food surface or migrating into the food interior. Households commonly peel off skins, wash with water, or use chemical methods to remove foreign substances including residual pesticides on the food surface. In this study, we measured the washing rate by comparing the pesticide concentrations before and after washing in the leafy vegetable perilla leaves and the fruits strawberries and apples, which were intentionally exposed to pesticides. We compared washing rates using tap water, a baking soda solution, and a commercially available food-specific cleaning solution. The target pesticides for analysis were azoxystrobin, bifenthrin, boscalid, difenoconazole, flubendiamide, and indoxacarb, and the residual pesticide analysis was performed using GC-MS/MS or LC-MS/MS. The removal rates of pesticides were highest with the food-specific cleaner, followed by baking soda and tap water in order.

• Environmental Engineering Research
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• v.22 no.1
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• pp.55-60
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• 2017

Provision of safe, accessible, and good water quality in the community is an important step towards reducing various waterborne illnesses. However, improving the quality of water should include spreading awareness to the public regarding the importance of cleaning their household water tanks. The aim of this study was to investigate the microbial quality of water of household water tanks in Dubai. The water samples from household water tanks were collected from forty houses, and a questionnaire was given to the residents to determine the history of the water tanks. The membrane filtration technique was used to quantify heterotrophic and total coliform bacteria on plate count agar and the violet red bile agar respectively. The overall results of this study have shown that 18 out of total 40 household water tanks contained different types of bacteria concentration level beyond local and widely accepted international standards. The overall results of this study indicated that there is a lack of awareness among residents regarding the importance of maintaining proper sanitation and hygiene of the household water tanks.

• Textile Coloration and Finishing
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• v.21 no.6
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• pp.1-11
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• 2009

Super-hydrophobic surface, with a water contact angle greater than $150^{\circ}$, has a self cleaning effect termed 'lotus effect'. We introduced super-hydrophobicity onto aramid/rayon mixture fabric with dual-scale structure by assembling silica nano-sol. Mixture fabric was treated with silica nano-sol, fluoric polymer using various parameters such as particle size, concentration. Silica nano-sol size were measured using particle size analyzer. Morphological changes by particle size were observed using field emission scanning electron microscopy(FE-SEM), contact angle measurement equipment. The contact angle of water was about $134.0^{\circ}$, $137.0^{\circ}$, $143.0^{\circ}$, $139.5^{\circ}$ and $139.0^{\circ}$ for mixture fabric coated with 100.2nm, 313.7nm, 558.2nm, 628.5nm and 965.4nm silica nano-sol, compared with about $120.0^{\circ}$ for mixture fabric coated with fluoric polymer. When we mixed particle sizes of 100.2nm and 558.2nm by 7:3 volume ratio, the contact angle of water was about $146.2^{\circ}$. And we mixed particle sizes of 313.7nm and 558.2nm by 7:3 volume ratio, the contact angle of water was about $141.8^{\circ}$. Also we mixed particle sizes of 558.2nm and 965.4nm by 7:3 volume ratio, the best super-hydrophobicity was obtained. In this paper, we fabricated the water-repellent surfaces with various surface structures by using four types of silica nano-sol, and we found that the dual-scale structure was very important for the super-hydrophobicity.

• Proceedings of the Membrane Society of Korea Conference
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• 2004.07a
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• pp.57-68
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• 2004

A demonstrative operation of a membrane system with its caparity of 3,600m$^3$/d was carried out using reservoir water as raw water for the application of membrane filtration system to drinking water treatment. The operation was undertaken at a constant flux of 0.9 m$^3$/m$^2$/d for three months. Backwashing with NaClO of 3 ppm was allowed for 30 seconds every 20 minutes of filtration. Physical cleaning was introduced after 69 times of filtration/backwashing cycle with air-scrubbing and backwashing for 1 minute, and flushing for 2 minutes. In this study, water treatment performance was investigated compared with the existing rapid sand filtration process. The membrane system was operated with no significant problems during the test period. Higher water quality was obtained in the membrane filtration than in the rapid sand filtration in terms of particulate matters such as turbidity and microbes. Although the finished water of the membrane filtration contained slightly higher concentration in dissolved matters than that of the conventional one, it met the drinking water standard. The demonstrative operation showed that membrane filtration has a reliability in drinking water treatment. Researches should be needed on cost analysis through long-term operation and optimization of operation condition for further application.