• Journal of Environmental Science International
• /
• v.12 no.12
• /
• pp.1235-1243
• /
• 2003

Under controlled conditions in an environmental chamber, 24 experiments were performed to compare the ability of a Variable-Air-Volume/Bypass Filtration System(VAV/BPFS) to remove indoor pollutants and to conserve energy with the ability of conventional Variable Air Volume(VAV) system. The specific conclusions of this paper were; first, the VAV/BPFS was more efficient than the VAV system in removing particulate matter, TVOC, and target VOCs. The total effective removal rate of PM for the VAV/BPFS was two times as high as that of the VAV system. The total effective removal rate of TVOC for the VAV/BPFS was 20 percent higher than that of the VAV system. Also each target VOC concentration was reduced by using the VAV/BPFS. Second, clean air delivery rate was increased by using VAV/BPFS due to additional filtration rate. Otherwise, the VAV/BPFS decreased outdoor supply air rate above 25 percent relative to the rate of VAV system. Third, total energy consumption by the VAV/BPFS was lower than that of the VAV system during the period with indoor thermal load, occupied time. The energy saving of the VAV/BPFS ranged from 11 to 16 percent. The VAV/BPFS improves indoor air quality more efficiently than the VAV system, and it reduced energy consumption. Retrofitting the VAV system with the VAV/BPFS was easy The use of VAV/BPFS is, therefore, recommended far buildings with VAV system as well as for buildings at designing stage.

• Journal of the Korean Ceramic Society
• /
• v.37 no.7
• /
• pp.693-699
• /
• 2000

Casting behavior of Zr(Y,Ce)O2 TZP/Mullite suspension during pressure filtration was investigated to prepare multi-layered Functionally Gradient Materials(FGM). The dispersion stabilities of each layer suspension were investigated by examination of zeta potential and viscosity. The each suspensions with 20 vol.% solid loading and 100 첸 of viscosity was prepared after fix of the dispersing agent (Sodium hexa-meta phosphate) and the binder (Hydroxyethyl cellulose), and then the cakes were formed at the 2.5 MPa~10.0MPa pressure range. The cake thickness of all suspensions was increased with the square root of time at the constant pressure, and the relations between filtration pressure(P)a nd dehydration rate (Q=dh/dt) showed that the flows of filtrates in the consolidated layers were laminar. The permeabilities were nearly constant during filtration, and kozeny constants(Kc) of the suspensions were 4.8~6.7. These valumes were seen as close to 5, which might be homogeneous particle packing during filtration. On the basis of those data, the multi layered compaction with 9 mm thickness and 52.5% green density was prepared by continuous pressure filtration.

• Journal of the Korean Wood Science and Technology
• /
• v.26 no.4
• /
• pp.86-91
• /
• 1998

The drainage was used to determine the specific filtration resistance for wood and non-wood fibers. The drainage rate is also affected by factors that can be changed on consistency, pressure drop across the mat, basis weight, additives, and viscosity. Recent development of theoretical studies in flow through porous media and filtration operation emphasize the urgent need for more accurate data for porosity and specific filtration resistance. This study was investigated to determine specific filtration resistance of Hw, Sw-BKP and Kenaf fiber by filtration experimental. Freeness levels selected were 150,250,and $350m\ell$ CSF. The average specific filtration resistance decreased as freeness increased and resistance of Sw-BKP was greater than that of Hw-BKP. The filtrate and porosity increased and specific filtration resistance decreased as particle size of fiber increased.

• Journal of Korean Society on Water Environment
• /
• v.31 no.3
• /
• pp.262-271
• /
• 2015

Laboratory study was undertaken to pursue the filter performance of a micro-filter module employing highly porous fiber media under a high filtration rate (over 1,500 m/day), faster than that of any conventional filter process. The effects of filtration rate, head loss, raw water turbidity, and filter aid chemicals on filter performance were analyzed. In spite of the extremely high filtration rate, the filter achieved an attractive efficiency, reducing the raw water turbidity by over 80%. As with other filter systems, the filter aid used (PAC in this study) greatly affected the performance of this particular fiber filter. Long term repetitive runs were additionally carried out to confirm the reproducibility of the filter performance. Finally, a comparison was carried out with other high rate filter systems which are either being tested for use in experimental studies, or are already commercially available.

• Journal of Veterinary Clinics
• /
• v.24 no.4
• /
• pp.577-583
• /
• 2007

It is important to obtain semen with good quality for efficient fertilization and pregnancy. To obtain these semen, various methods have been developed but most of these methods are time consuming and require costly equipment. Therefore, the objective of this research is to investigate the usability of column filtration system as quick and simple method to get sperm with better quality. Ejaculates were obtained from 5 dogs and analyzed with basic quality parameters before each filtration. Sperm concentration was adjusted to $5{\times}10^7/ml$ after dilution. The experimental groups were divided into non-filtered group(control) and filtered groups(glass wool, Sephadex 5% and Sephadex 20%). Ejaculates were filtered through each filter system and assessed by recovery rate of sperm, motility, normal morphology, CFDA/PI stain and plasma membrane integrity(hypo-osmotic swelling test, HOST). The lowest recovery rate of spermatozoa was recorded in glass wool filtration group, followed by 20% Sephadex filtration group(p<0.05). There was no significant difference between control(non-filtered) and 5% Sephadex filtration poop. Also, there was no significant difference of sperm motility assessed under light microscope among experimental groups. Morphological normality of canine spermatozoa was the highest in the glass wool filtration group and the lowest in the 5% Sephadex filtration group with no significant differences versus 20% Sephadex filtration and control group, respectively(p<0.05). Viability of canine sperm assessed by CFCA/PI staining was the highest in the glass wool filtration poop with no significant difference versus the control group, and the lowest in the 20% Sephadex filtration group with no significant difference versus 5% Sephadex filtration group, respectively(p<0.05). HOS values of canine sperm was the highest in the 20% Sephadex filtration group with no significant difference versus 5% Sephadex filtration group, and the lowest in the control poop with no significant difference versus glass wool filtration group, respectively(p<0.05). Therefore, these results indicated that filtration treatment for extended canine sperm would be useful method to get sperm with better quality by trapping the damaged sperm, consequently filter would be physical barrier against injured or immotile sperm.

• Asian-Australasian Journal of Animal Sciences
• /
• v.17 no.6
• /
• pp.755-759
• /
• 2004

The present investigation was carried out to assess the effect of Sephadex (G-15) filtration on the post thaw bull semen quality and conception rate. Post thaw unfiltered (control) and Sephadex filtered semen from four healthy bulls (three cross bred and one pure bred Holstein Friesian) were subjected to microscopic examination viz. sperm concentration, individual motility, live sperm count and sperm morphology. Sixty-two healthy, normal cycling crossbred cows were inseminated with post thaw unfiltered (n=32) and filtered semen (n=30). Sephadex filtration of post thaw semen significantly (p<0.05) decreased total sperm concentration and sperm with abnormal head, mid piece and tail. The overall average total sperm concentration, head and tail defects in filtered semen decreased significantly (53.4, 1.2 and 6.4 million) than in the unfiltered semen (80.4, 2.4 and 15.7 million, respectively). However, after filtration significant (p<0.05) increase in overall average motile and live sperm concentration were observed (38.8 and 38.0) as compared to unfiltered semen (29.2 and 32.0 million, respectively). The overall conception rate recorded was 21.9% with post thaw unfiltered semen and 56.7% with filtered semen. It was concluded that Sephadex filtration of post thaw semen improved its quality and conception rate.

• Journal of Korean Society of Water and Wastewater
• /
• v.18 no.5
• /
• pp.673-679
• /
• 2004

Particle breakthrough can occur by either the breakoff of previously captured particles (or flocs) or the direct passage of some influent particles through the filter. Filtration experiments were performed in a laboratory-scale filter using spherical glass beads with a diameter of 0.55 mm as collectors. A single type of particle suspension (Min-U-Sil 5, nearly pure $SiO_2$) and three different destabilization methods (pH control, alum and polymer destabilization) were utilized. The operating conditions were similar to those of standard media filtration practice: a filtration velocity of 5 m/h. To assess the possibility of particle detachment during the normal filtration, a hydraulic shock load (20% increase of flow rate) was applied after 4 hours of normal filtration. The magnitude of particle detachment was proportional to the particle size for non-Brownian particles. At the same time, less favorable particles, i.e., particles with larger surface charge, were easily detached during the hydraulic shock load. Therefore, proper particle destabilization before filtration is crucial for maximum particle removal as well as minimum particle breakthrough.

• The Korean Journal of Physiology
• /
• v.20 no.1
• /
• pp.103-124
• /
• 1986

Since it has been suggested that atrial receptor may be involved in the mechanism of extracellular volume regulation, it was shown that the granularity of atrial cardiocytes can be changed by water and salt depletion, and that an extract of cardiac atrial tissue, when injected intravenously into anesthetized rats, was shown to cause a large and rapid increase in renal excretion of sodium. Various natriuretic peptides were isolated and synthetized, and the effects were investigated by many workers. Most studies, however, have been carried out under anesthesia and there have teen some controversies over direct effect of the factor on the renal function. Therefore, it was attempted in this study to access the effects of an atrial extract and a synthetic natriuretic factor in unanesthetized rabbits. Intrarenal arterial infusion of atrial extract caused a rapid increase of urinary volume and excretion of sodium. Glomerular filtration rate and renal plasma flow were both increased with no change in filtration fraction. The ventricular extract produced no change in urinary excretion of electrolytes, nor in renal hemodynamics. Intrarenal infusion of synthetic atrial natriuretic factor caused increases of renal excretory rate of sodium, chloride and potassium, and $FE_{Na}$. Glomerular filtration rate, renal plasma flow increased. And free water clearance also increased. Accentuated excretory function correlated well with increased glomerular filtration rate and renal plasma flow during infusion and for 10 minutes following the cessation of the infusion. Renin secretion rate decreased during constant infusion of atrial natriuretic factor. However, no correlation was found with the changes in glomerular filtration rate, renal plasma flow, or urinary excretion of sodium. These results suggest that atrial extract or atrial natriuretic factor induces changes in renal hemodynamics, as in excretion of electrolytes either indirectly through hemodynamic changes or directly by inhibiting tubular reabsorption. At the same time, renin secretory function is affected by the factor possibly through an unknown mechanism.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.45 no.5
• /
• pp.160-170
• /
• 2003

A pilot study was performed to examine the feasibility of intermittent slow sand filtration for agricultural reuse of reclaimed water. The effluent of biofilter for 16-unit apartment was used as influent to the slow sand filtration system at 0.6 $m^3$/day loading rate using 15 seconds spray in every 10 minutes on the about 1 $m^2$ surface area and 0.5 m depth. The influent concentrations of total coliform (TC), fecal coliform (FC) and E. coli were in the range of 10.000 MPN/100 mL. and they were reduced to less than 1,000 MPN/100 mL after filtration with average of 320, 270, and 154 MPN/100 mL, respectively, showing over 95 % removal. Turbidity and SS were improved effectively and their average concentration was reduced to 0.8 NTU and 1.7 mg/L, respectively, and removal rate was about 50 %. Average BOD and COD concentrations were also reduced substantially to 2.6 and 25.8 mg/L with about 55 and 21 % removal rate, respectively. Nutrients removal was relatively low and removal rate for T-N and T-P was low however, remaining nutrients might be beneficial and less concerned in case of agricultural reuse. The concentration of biofilter effluent used in this experiment was in the range of secondary treatment effluent but slightly stronger than the one from existing wastewater treatment plants (WWTPs). Therefore, intermittent slow sand filtration might be also applicable to the effluent from WWTPs as long as its agricultural reuse is available. Considering stable performance and effective removal of bacterial indicators as well as other water quality parameters, low maintenance, and cost-effectiveness, the intermittent slow sand filtration was thought to be an effective and feasible alternative for agricultural reuse of reclaimed water. This paper is a preliminary result from pilot study and further investigations are recommended on the optimum design parameters before full scale application.

• Journal of Korea Water Resources Association
• /
• v.35 no.2
• /
• pp.213-220
• /
• 2002

This reserch was focused upon experimental study for wastewater reuse and conducted to evaluate optimum operating conditions of rapid filtration process such as filter flow rate, filtration time and backwashing condition for reuse of secondary-treated effluent using the pilot plant installed in real wastewater treatment plant. Also, the experiment on treatment char-acteristics of coagulant-added activated sludge process was performed to compare with activated sludge succeeded to rapid filtration. As the filtration velocity was 100m/day, the filtration time of the rapid filter connected with activated sludge system was revealed to 40 hours. Backwashing of filter was conducted by water wash and air scour. The optimum backwashing time and backwash flow rate were 10min and 10LPM, respectively. The quantity of backwashing water of the rapid filter was about 2% of total treated water.