• Membrane and Water Treatment
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• 제5권2호
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• pp.73-86
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• 2014

Membrane fouling is a major challenge limiting the use of membrane applications. In this study high induced shear rates were utilized at the membrane surface in order to reduce the organic and inorganic scaling by using the torsional vibration of flat sheet membranes. The performances of a vibratory shear-enhanced processing (VSEP) system for the ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) membrane filtration of industrial dairy wastewater were investigated. The vibration and non-vibration methods were compared with the same membrane and operational parameters during the purification of real dairy industrial process wastewater. In the initial experiments, short-term tests were carried out in which the effects of vibration amplitude, recirculation flow rate and transmembrane pressure were measured and compared. The permeate flux, turbidity, conductivity and chemical oxygen demand (COD) reduction of dairy wastewater were investigated by using UF, NF and RO membranes with vibration and non-vibration methods. In the subsequent experiments, concentration tests were also carried out. Finally, scanning electron microscopy (SEM) revealed that the vibration method gave a better performance, which can be attributed to the higher membrane shear rate, which reduces the concentration of solids at the membrane, and the transmission.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 추계 학술발표회
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• pp.498-507
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• 2008

The mixture of bentonite powder and water is generally used to maintain the stability of excavation surface during the construction of vertical cutoff walls. The filter cake on the sidewall surface is the result of filtration of slurry into the adjacent soil formation. The filter cake is believed to have a very low hydraulic conductivity compared to that of the cutoff wall. This paper evaluates hydraulic conductivities of bentonite filter cakes set up with three types of bentonites under various pressure levels. A modified fluid loss test was employed in this experiment. Theory of filtration process was reviewed to explain the procedure in the present experiment. Hydraulic conductivity of the filter cakes with consideration of the filter medium resistance was evaluated. The results of the experiment with two calculation methods and discussion are presented to show the efficiency of the modified fluid loss test.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 추계 학술발표회
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• pp.1502-1511
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• 2008

The mixture of bentonite powder and water is generally used to maintain the stability of excavation surface during the construction of vertical cutoff walls. The filter cake on the sidewall surface is the result of filtration of slurry into the adjacent soil formation. The filter cake is believed to have a very low hydraulic conductivity compared to that of the cutoff wall. This paper evaluates hydraulic conductivities of bentonite filter cakes set up with three types of bentonites under various pressure levels. A modified fluid loss test was employed in this experiment. Theory of filtration process was reviewed to explain the procedure in the present experiment. Hydraulic conductivity of the filter cakes with consideration of the filter medium resistance was evaluated. The results of the experiment with two calculation methods and discussion are presented to show the efficiency of the modified fluid loss test.

• Membrane and Water Treatment
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• 제8권2호
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• pp.185-199
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• 2017

Low-pressure membrane filtration is increasingly used for tertiary treatment of wastewater effluent organic matter (EfOM), mainly comprising organic base/neutral compounds. In-line coagulation with underdosing, charge neutralization, and sweep floc conditions prior to ultrafiltration (UF) was studied to determine removals of the EfOM components and consequent reduction of fouling using polyethersulfone membranes. Coagulation and UF substantially reduced fouling for all coagulation conditions while removing from 7 to 38% of EfOM organic acids. From 7 to 16% of EfOM organic base/neutrals were removed at neutral pH but there was no significant removal for slightly acid coagulation conditions even though fouling was substantially reduced. Sweep floc produced the lowest resistance to filtration but may be inappropriate for in-line use due to the large added volume of solids. Charge-neutralization resulted in poor recovery of the initial flux with hydraulic cleaning. Under-dosing paralleled sweep floc in reducing hydraulic resistance to filtration (for sub-critical flux) and the initial flux was also easily recovered with hydraulic cleaning. Hydrophobic and hydrophilic base/neutrals were identified on the fouled membranes but as previously reported the extent of fouling was not correlated with accumulation of organic base/neutrals.

• 한국산업융합학회 논문집
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• 제24권5호
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• pp.581-587
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• 2021

In recent years, contamination of drinking water sources has emerged as a serious social problem, such as a large number of impurities in tap water or groundwater or the supply of suitable water due to rust of pipes. Although the government and public institutions are implementing various measures to protect water sources, they cannot improve water quality in a short period of time because of the enormous cost involved. Therefore, in recent years, preference has been given to a device that converts tap water, which is hard water, into soft water by installing a separate water softener at the faucet from which tap water is discharged. However, the existing filtration device has a problem that filtration performance is gradually lowered when impurities accumulate in the filter, requiring continuous filter replacement. In this study, the optimal design of the filter housing was performed to develop a water softener that can be washed when impurities accumulate on the filter inside the water softener connected to the faucet. For optimal design of the filter housing, fluid and fluid-structural interaction analysis were performed on the design pressure to determine the shape and thickness of the housing, and design review was performed through prototype.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집E
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• pp.154-157
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• 2001

The effects of pleating parameters on the performance of cylindrical cartridge air filters was experimentally studied. The tested filters are 150 mm in outer diameter and 700 mm in length. As the pleat count increases, the pressure drop across a cartridge filter is decreased for a constant pleat depth and flow rate. This is due to the increased filtration area which brings out less pressure loss of the filter. However, in the case of the filters having the pleat depth of 40 mm, the inner diameter of the cartridges is so small that the pressure loss is greatly increased.

• 한국대기환경학회지
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• 제16권2호
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• pp.179-190
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• 2000

The main object of this study was to investigate experimentally the characteristics of electrostatic cyclone-bag filter with upper tangential inlet in order to overcome the low collection efficiency for the submicron particle and high pressure drop which were main problems of general fabric bag filters. The experiment was carried out for the analysis of collection efficiency and pressure drop of electrostatic cyclone-bag filter comparing to those of fabric bag filter with various experimental parameters such as the inlet velocity(filtration velocity) and applied voltage etc. In the results the upper tangential inlet type showed higher collection efficiency for submicron particles below 2 ${\mu}{\textrm}{m}$ in diameter than that of center inlet and over 99.9% for overall collection efficiency. Pressure drop reduction ratios were shown as 40-50% for the applied voltage 0kV by centrifugal force and 70-90% for 20k V by the centrifuga and electrostatic force with the tangential inlet velocity (12-21m/s)

• Journal of Chest Surgery
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• 제32권6호
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• pp.518-524
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• 1999

배경: 본 연구에서는 개심술을 시행받은 소아 환아에 대하여 심폐기 이탈 직후 실시한 변형 초여과법의 효과를 임상례의 분석을 통하여 입증하였다. 대상 및 방법: 1997년 1월부터 12월까지 변형 초여과법을 실시한 체중 7 kg 이하의 청색성 심질환을 보이는 50명의 환아들과 변형 초여과법을 실시하지 않은 체중 7 kg 이하의 청색성 심질환을 갖은 50명의 환아들을 대상으로 하여 초여과 전후의 적혈구용적률, 혈역학적 수치와 체중의 변화를 비교하였다. 결과: 평균나이는 변형 초여과군이 4.1개월, 대조군이 3.1개월이었으며, 체중은 변형 초여과군이 4.8 kg, 대조군이 4.6 kg으로 두 군 간에 통계적인 차이가 없었다. 변형 초여과군에서는 평균 7분 동안 매 환아당 60.0$\pm$29.2 cc/kg의 수액을 여과시켰다. 변형 초여과 직후에는 적혈구용적률이 36.1%로 대조군의 26.4%에 비해 유의하게 높았다(p=0.001). 심폐우회술후 흉관을 통한 배액량은 두 군간에 차이가 없었으나(p=0.28), 수혈량은 변형 초여과군이 대조군에 비해 유의하게 적었다(p=0.04). 변형 초여과후 중심정맥압이 감소하였고(p=0.02) 수축기(p=0.0001)와 이완기혈압(p=0.0001)은 증가하였고 맥박수는 감소하였으나(p=0.02), 대조군에서는 유의한 차이가 없었다. 변형 초여과후 체중의 증가는 대조군에 비해 유의하게 감소하였다(p=0.04). 결론: 연구자들은 본 연구를 통하여 소아환아의 개심술에 적용된 변형 초여과법이 조작이 간편하고 효과적으로 혈액을 농축시키고, 단시간내에 정상 혈역학으로의 환원을 가능케 하였으며, 술후 체수분 조절에도 탁월하여 수술결과를 보다 양호하게 만들 수 있다는 사실을 입증하였다.

• 한국자동차공학회논문집
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• 제4권5호
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• pp.179-186
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• 1996

The magnetic fibrous polymeric oil filter for automotive was obtained by pneumoextrusion processing prepared from thermoplastic polymer(polyamide) containing magnetic particulate filer (Ba ferrite), and treated subsequently in a magnetic fields. Using an oil filter tester and particle quantifier, the dependence of filtrational characteristics of the magnetic oil filter on the parameters of mean pore sizes and magnetic properties were analyzed. Also experimental engine-bed test of oil filters was investigated. The magnetic fibrous polymeric filter was shown to possess a highly filtration efficiency in filtering the fine metal particles with increasing the magnetic force of filter element. In this study, we knew that efficiency of magnetic fibrous polymeric filter was dependent on the magnetic strength of the filter elements.

• 한국공작기계학회논문집
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• 제17권1호
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• pp.158-164
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• 2008

In this paper, the performance of wet type filter for diesel engine combustion air has been studied with effects of air temperature, humidity, and pressure. After experiments are performed without diesel engine, it has been investigated the applicability to diesel engine. Wet type filter for diesel engine combustion air had advantages that it is not necessary to change air filter and that engine exhaust gas is environmentally friendly due to low NOx and particulate emission. Also, the filtration performance has been carried out with smoke shell.