• 산업기술연구
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• 제20권A호
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• pp.113-122
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• 2000

Column tests in the laboratory were preformed to investigate characteristics of settling process of dredged soil sampled from in-situ. Test results were analyzed by using the existing theories on discrete settling and hindered settling. From column tests of monitoring the interface with time, settling was found to be a linear process with time and the settling rate was increased with initial water content of slurry. The settling rate was also observed to decrease with increasing initial height of slurry. Most of settling process were composed of flocculation, hindered settling and self-weight consolidation. On the other hands, flocculation of soil during settling was observed and it was found that the size and density of flocculated particles could be analyzed by using the method proposed by Richardson and Zaki.

• Asian-Australasian Journal of Animal Sciences
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• 제23권9호
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• pp.1190-1197
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• 2010

The objective of the study was to determine the relationship between faecal egg counts and nutritionally-related blood metabolites in Nguni goats of South Africa. Body weights, body condition scores (BCS), FAMACHA scores, faecal and blood samples were collected from 96 Nguni castrates. Faecal samples were analysed using the modified McMaster technique for nematodes and the sedimentation method for trematodes. Blood was analysed for packed cell volume (PCV), glucose, cholesterol, total protein, albumin, urea and creatinine. Season had an effect on glucose, globulin, total protein, creatinine, PCV and faecal egg counts (FEC). Globulin, PCV, creatinine and FEC were significantly higher in the wet season compared to the dry season. A quadratic relationship existed between faecal egg count loads and BCS whilst negative linear relationships were observed between faecal egg counts and creatinine, albumin and cholesterol levels of Nguni goats.

• 한국분말재료학회지
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• 제5권2호
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• pp.133-138
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• 1998

The effect of $\beta$-$Si_3N_4$ seeding on microstructural development of silicon nitride based materials has been investigated. In particular, to observe more distinctly the abnormal grain growth in pressureless sintering, fine $\alpha$-$Si_3N_4$(mean particle size: 0.26 ${\mu}m$) powder classified by sedimentation method was used. It was possible to prepare silicon nitride with abnormally grown grains under low nitrogen pressure of 1 atm thanks to the heterogeneous nucleation on $Si_3N_4$ seed particles. The size and morphology of silicon nitride grains were strongly influenced by the presence of $\beta$-$Si_3N_4$ seed and overall chemical composition. For specimens with initially low $\beta$-content, the large grains grew without a significant impingement by other large grains. On the contrary, for specimens with initially high $\beta$-content, steric hindrance was effective. The resulting microstructure was less inhomogeneous and characterized by unimodal grain size distribution.

• Membrane and Water Treatment
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• 제8권5호
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• pp.423-435
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• 2017

Settling Basins are one of the most important and popular methods for removal of suspended sediments irrigation and drainage networks or power canals taking off from an alluvial river and wastewater treatment plant. Improving the performance and so increasing sediment removal efficiency of settling basins by an alternative method is necessary. In the present work, the effect of baffle and its angle of attack with the flow (${\theta}$) on the sediment removal efficiency is investigated by conducting a series of experiments on a straight canal with 8 m length, 0.3 m width and 0.5 m height and 3 m length of basin equipped with an adjustable glass baffle. A numerical analysis has been carried out using ANSYS Fluent 3D software (a general purpose computational fluid dynamics simulation tool) for three Froude numbers from the experiments. The numerical and experimental results were found to match reasonably well.

• 상하수도학회지
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• 제18권6호
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• pp.715-723
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• 2004

The quantity of residuals generated from water treatment plants depends upon the raw water quality, dosage of chemicals used, performance of the treatment process, method of sludge removal, efficiency of sedimentation, and backwashing frequency. Sludge production by the physical separation of SS occurs under quiescent conditions in the primary clarifier, where suspended solids are allowed to settle and to consolidate on the clarifier bottom. Raw primary sludge results when the settled solids are hydraulically removed from the tank. The relative solid and liquid fractions of a slurry are most commonly described by the solids concentration, expressed as mg/L or percent solids. The purpose of the present investigation is to estimate a suitability on the design capacities of residuals treatment facilities by the quantity of dewatered sludge generated from water treatment plants.

• 한국분말재료학회지
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• 제19권4호
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• pp.304-309
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• 2012

The purpose of our study was to develop the fabrication method of porous diatomite ceramics with a porosity gradient by centrifugal molding. The processing variables of centrifugal molding were derived from Stoke's law of sedimentation, which were the radius of the particles, the acceleration due to centrifugal molding and the dynamic viscosity of the slurry. And these could be controlled by ball-milling conditions, centrifugal conditions, and the addition of methyl cellulose, respectively. The effects of processing conditions on the gradient pore structure of diatomite were investigated by particle size analysis, scanning electron microscope, and mercury porosimeter.

• 상하수도학회지
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• 제25권5호
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• pp.777-782
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• 2011

The residual treatment facilities in WTP(water treatment plant) play an important role in solid-liquid separation. At present, it is difficult to solve problems related with thickening and dewatering of WTP sludge, and discharging waste water to river. The quantity of residuals generated from water treatment plants depends upon the raw water quality, dosage of chemicals used, performance of the treatment process, method of sludge removal, efficiency of sedimentation, and backwashing frequency. Sludge production by the physical separation of SS(Suspended Solid) occurs under quiescent conditions in the primary clarifier, where SSs are allowed to settle and to consolidate on the clarifier bottom. Raw primary sludge results when the settled solids are hydraulically removed from the tank. In this study, Drawing characteristics of the sludge thickening in the thickener of Water Treatment Plants was simulated by Using CFD(Computational Fluid Dynamics.

• 한국유체기계학회 논문집
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• 제9권5호
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• pp.22-27
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• 2006

Sedimentation phenomenon of suspended solids occurs by the gravitational force. Pollution particles are separated from slowly flowing waste water in clarifier. Recently, the sludge suction collector is Preferred rather than the scraper type sludge collector due to the enhancement of the clarifier efficiency. The sludge suction collector is usually operated by the user's experiences without any scientific and/or technical consideration. To evaluate the performance of sludge suction collector, the three dimensional numerical simulation was conducted by the finite volume method. To analyze the performance, the velocity vectors and the suction flow rates of the orifices were investigated. The result showed that each suction flow rate through out the collector was equivalent in the sludge suction collector and the efficiency of suction collector was good to remove high concentrated sludge in clarifier.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1851-1856
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• 2004

Sedimentation phenomenon of suspended solids occurs by the gravitational force. Pollution particles are separated from slowly flowing wastewater in clarifier. Recently, the sludge suction collector is preferred rather than the scraper type sludge collector due to enhancement of the clarifier efficiency. The sludge suction collector is usually operated by the user's experiences without any scientific and/or technical consideration. To evaluate the performance of sludge suction collector, the three dimensional computer simulation was conducted by the finite volume method. To analyze the performance, the velocity vectors and the suction flow rates of the orifices were investigated. The result showed that each suction flow rate through out the collector was equivalent in the sludge suction collector and the efficiency of suction collector was good to remove high concentrated sludge in clarifier.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2003년도 유체기계 연구개발 발표회 논문집
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• pp.415-420
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• 2003

Sedimentation phenomenon of suspended solids occurs by the gravitational force. Pollution particles are separated from slowly flowing wastewater in clarifier. Recently, the sludge suction collector is preferred rather than the scraper type sludge collector due to enhancement of the clarifier efficiency. The sludge suction collector is usually operated by the user's experiences without any scientific and/or technical consideration. To evaluate the performance of sludge suction collector, the three dimensional computer simulation was conducted by the finite volume method. To analyze the performance, the velocity vectors and the suction flow rates of the orifices were investigated. The result showed that each suction flow rate through out the collector was equivalent in the sludge suction collector and the efficiency of suction collector was good to remove high concentrated sludge in clarifier.