• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.744-747
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• 2004

An electric precipitator in a thermal electric power plant is essential equipment for preventing air environment pollution. However, it is difficult for the existing control systems to make efficient effects on dust collection. This is because AVC and ERC consist of independent, separate systems in the existing systems. To solve this problem, we developed an intelligent distributed control system, which makes optimal control possible through connection operations between the control systems. In this paper, we analyzed system performance and fly ash reduction effects through the developed system structure, development contents and its actual application to power plant.

• International Journal of Industrial Entomology and Biomaterials
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• v.4 no.1
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• pp.19-22
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• 2002

Rotary mountages are the best mountages among all the mountages that are used in sericultural areas. But to use this mountage more space, separate mounting hall & requires more labour to pickup the matured worms. to over come these problems, self mounting method is adopted to save the time Er labour, But the mounting rate is generally less. To accelerate the mounting rate different repellents viz; saw dust, phytoecdysone, 1% cresol with paddy husk, lime, kaolin, gormalin chaff were used in the present study. The results indicated that highest number of larvae climbed the mountage in 1% cresol with paddy husk, followed by phytoecdysone and lime. It is observed that the use of repellents at wandering stage accilerates mounting rate and did not affect the quality of the cocoons and reeling characters.

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.2600-2602
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• 2005

An electric precipitator in a thermal electric power plant is essential equipment for preventing air environment pollution. However, it is difficult for the existing control systems to make efficient effects on dust collection. This is because AVC and ERC consist of independent, separate systems in the existing systems. To solve this problem, we developed an intelligent distributed control system, which makes optimal control possible through connection operations between the control systems. In this paper, we analyzed system performance and fly ash reduction effects through the developed system structure, development contents and its actual application to power plant.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.6
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• pp.1559-1566
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• 1994

Using the finite element method, the contact force, contact band width and temperature distribution of lip seals analyzed for the interference including some nonlinearities such as material nonlinearity, geometrical nonlinearity and nonlinear contact boundary condition. The calculated results showed that the contact stress concentrated on the contact zone between the garter spring and the rubber toward the flex side, the contact edge of lip seals. The high contact forces due to the increased interference separate the sealing gap between the lip edge and the rotating shaft. This may lead to leak the sealed oil.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1683-1684
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• 2008

For direct detection of microbes in air, samples have to be collected but environmental particles such as dust are also trapped in such samples. Therefore the isolation of target bacteria from non-biological materials of similar size is of great importance in the identification of such organisms. Dielectrophoresis is an emerging technique that can rapidly separate cells in microfluidics. In this paper we proposed a new method for the separation of airborne microbes using condensation and dielectrophoresis. This system could be used as a continuous flow through separation system for various particles and utilized as a pretreatment technique for microbe detection.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.6 no.2
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• pp.265-271
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• 1996

This study was conducted to investigate distribution of lead particles by operation of industry, to evaluate the effect of particle size on the absorption to workers, and to recommend the Occupational Health Standard for lead. Total lead concentrations in the secondary smelting industry were higher than those in the battery and litharge manufacturing industry. Total lead concentrations in other industries except radiator manufacturing industry exceeded the standard of $50{\mu}g/m^3$. Only radiator manufacturing industry indicated lead concentrations significantly lower than those in other industries(p<0.05). Average blood lead level of workers was $85.1{\mu}g/dl$ in secondary smelting manufacturing, $51.3{\mu}g/dl$ in the battery manufacturing, and below $40{\mu}g/dl$ in the litharge and radiator manufacturing industry. Blood lead levels of workers by industry were significantly different(p<0.05). From relationship between airborne lead concentrations by size and lead in blood, confidence limits of airborne lead concentration equivalent to $40{\mu}g/dl$ of permissible limit in blood, was $147.9-489.8{\mu}g/m^3$ as total lead and $28.8-79.4{\mu}g/m^3$ as ACGIH-RPM. It is recommended that two separate occupational health standards for lead should be established by particle size. Airborne concentration of $150{\mu}g/m^3$ as fatal lead dust and $30{\mu}g/m^3$ as respirable lead dust was recommended.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.259-263
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• 2001

There are several steps such as slicing, lapping, chemical etching and mechanical polishing in the silicon wafer production process. The chemical etching step is necessary to remove damaged layer caused In the slicing and lapping steps. The typical etching liquor is the acid mixture comprising nitric acid, acetic acid and hydrofluoric acid. At present, the waste acid is treated by a neutralization method with a high alkali cost and balky solid residue. A solvent extraction method is applicable to separate and recover each acid. Acetic acid is first separated from the waste liquor using 2-ethlyhexyl alcohols as an extractant. Then, nitric acid is recovered using TBP(Tri-butyl phosphate) as an extractant. Finally hydrofluoric acid is separated with the TBP solvent extraction. The expected recovered acids in this process are 2㏖/l acetic acid, 6㏖/1 nitric acid and 6㏖/l hydrofluoric acid. The yields of this process are almost 100% for acetic acid and nitric acid. On the other hand, it is important to recover and reuse the metal values contained in various industrial wastes in a viewpoint of environmental preservation. Most of industrial products are made through the processes to separate impurities in raw materials, solid and liquid wastes being necessarily discharged as industrial wastes. Chemical methods such as solvent extraction, ion exchange and membrane, and physical methods such as heavy media separation, magnetic separation and electrostatic separation are considered as the methods for separation and recovery of the metal values from the wastes. Some examples of the application of solvent extraction to the treatment of wastes such as Ni-Co alloy scrap, Sm-Co alloy scrap, fly ash and flue dust, and liquid wastes such as plating solution, the rinse solution, etching solution and pickling solution are introduced.

• Magazine of the Korean Society of Agricultural Engineers
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• v.17 no.1
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• pp.3655-3665
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• 1975

This study was intended to develop a method for measuring the grain separating performance of threshers. The grain separating apparatus used for the experiment was designed and constructed, the function of which was to separate pneumatically mature and immature grain, chaff, straw, dust, and other impurities from the products of threshing. The apparatus has five material outlets where grains and impurities are fallen down by separation depending upon the specific gravity of the material white it moves above the outlets. The principle of design was to separate the mixture of mature grain, immature grain and chaff as distinct as possible, and to induce the mature grains onto the first outlet, the immature grains onto the second and the third, and the straw wastes onto the forth and the fifth outlets. The developed apparatus was tested to evaluate its separating performance with two rice varieties (Tongil and Mine-hikari) at different moisture levels and air velocities. The optimum conditions for operating the apparatus were found from experiment. The results are summarized as follows; 1. The degrees of separation, especially the amount of immature grain contained in the mature paddy, were dependent upon air speed delivered. The optimum air velocities for this apparatus for each levels of grain moisture contents were found from a series of experiments as follows; 14.7-15.3m/sec. for grain of 16 percent moisture content in wet basis, 15.3-16.0m/sec. for 20 percent, and 16.0-16.4m/sec for 24 percent. 2. Composition ratios determined based on the brine separating method was fairly well acted upon the developed apparatus, indicating its recollecting rate of the mature grains as 97.6 to 99.9 percent. The developed separatus acted similarly upon the two rice varieties which had different composition of immature paddy grain. In other words, the separating performance by the apparatus had a good correlation with the one by the brine separating method. 3. As immature grains were separated out unsatisfactory in these experiments than the brine separating method, further investigation may be needed to improve a separating performance of these materials. But the results obtained suggested a possibility of using the tester to replace the current hand separating method, ther eby enabling more consistent test results and also eliminating nearly all costly hand seperating operations.

• The Journal of the Convergence on Culture Technology
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• v.10 no.5
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• pp.619-629
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• 2024

Innovation means the creation of new value by changing existing things. Dyson's Cyclone vacuum cleaner, a representative innovative product, eliminated the dust filter that had existed in vacuum cleaners for over 100 years. Instead of directly improving the dust filter that reduces suction power, this product was invented by asking the essential question, 'How do we separate dust in the air?' Creative innovation happens when the essence of the problem is properly understood. TRIZ(Theory of Inventive Problem Solving) analyzed numerous invention patents and discovered that innovative results in problem solving appear depending on the existence of contradictions in the problem and how to creatively overcome the contradictions. Based on this, it was systematized into a methodology along with other powerful principles of problem solving. Therefore, TRIZ is a powerful tool for creative and innovative problem solving. However, for creative innovation, it is not easy to properly identify the contradictions in the problem and apply them to solve the problem. However, for creative innovation, it is not easy to properly identify the contradictions in the problem and apply them to solve the problem. In addition, depending on which contradiction is selected, not only the direction of problem solving but also the final solution varies, but researches on this are very lacking. To overcome these difficulties, this study first introduced the concepts of existence contradiction and state contradiction, presented a new problem-solving process, and verified its validity by applying it to toothbrush patent cases. Although there are limitations in applying it to various cases, we hope that the new concept of contradiction presented for the first time in this study and the problem-solving process through it will contribute to producing innovative results.

• Ocean Science Journal
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• v.43 no.2
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• pp.81-90
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• 2008

A study of estuarine flows during a neap tide was performed using 13-hour roving acoustic Doppler current profiles (ADCP) and conductivity-temperature-depth (CTD) profiles in the Altamaha River estuary, Georgia, U.S.A. The least-squared harmonic analysis method was used to fit the tidal ($M_2$) component and separate the flow into two components: the tidal and residual ($M_2$-removed) flows. We applied this method to depth-averaged data. Results show that the $M_2$ component demonstrates over 95% of the variability of observation data. As the flow was dominated by the $M_2$ tidal component in a narrow channel, the tidal ellipse distribution was essentially a back-and-forth motion. The amplitude of $M_2$ velocity component increased slightly from the river mouth (0.45 m/sec) to land (0.6 m/sec) and the phase showed fairly constant values in the center of the channel and rapidly decreasing values near the northern and southern shoaling areas. The residual flow and transport calculated from depth-averaged flow shows temporal variability over the tidal time scale. Strong landward flows appeared during slack waters which may be attributed to increased baroclinic forcing when turbulent mixing decreases.