• Journal of the Korean Ceramic Society
• /
• v.34 no.4
• /
• pp.343-350
• /
• 1997

To fabricate the ceramic/metal(SiC/ Al alloy) composite, SiC preform was prepared by Pressureless Powder Packing Forming Method and 6061 Al alloy was infiltrated into the preform. Uniform compact having an average pore size of 10 ${\mu}{\textrm}{m}$ and narrow pore size distribution was prepared. Phenolic resin solution(40 wt%) was penetrated into the SiC compact, and then the compact was preheated at the temperature of 120$0^{\circ}C$. The pore size distribution and the microstructure of the preform were not changed by preheating. An uniform microstructure without any crack in the preform was obtained in SiC-Al alloy composite. The infiltration of 6061. Al alloy into the preform began at the temperature of 130$0^{\circ}C$ and the amount of infiltration increased in proportion to the infiltration temperature and the soaking time. The increasement rate of the infiltration amount decreased after 3 h. As a result of the infiltration at 140$0^{\circ}C$ for 4 h, Al alloy was well distributed in the interparticle channels and the relative density of the composite was above 98%. The strength and the fracture toughness of the composite were 303 MPa and 21.65 MPam1/2, respectively.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.46 no.4
• /
• pp.250-257
• /
• 2020

Objectives: Palatal infiltration is the most painful and uncomfortable anesthesia technique for maxillary impacted third molar surgery (MITMS). This approach could cause patients distress and aversion to dental treatment. The aim of this study was to evaluate the anesthetic efficacy of a buccal infiltration injection without a palatal injection in MITMS. Materials and Methods: This prospective research study was a crossover split mouth-randomized controlled trial. Twenty-eight healthy symmetrical bilateral MITMS patients (mean age, 23 years) were randomly assigned to two groups. Buccal infiltration injections without palatal injections were designated as the study group and the buccal with palatal infiltration cases were the control group, using 4% articaine and 1:100,000 epinephrine. The operation started after 10 minutes of infiltration. Pain assessment was done using a visual analogue scale and a numeric rating scale after each injection and extraction procedure. Similarly, the success rate, hemodynamic parameters, and additional requested local anesthetic were assessed. Results: The results showed that the pain associated with local anesthetic injections between both groups were significantly different. However, the success rates between the groups were not significantly different. Postoperative pain was not significant between both groups and a few patients requested an additional local anesthetic, but the results were not statistically significant. For hemodynamic parameters, there was a significant difference in systolic pressure during incision, bone removal, and tooth elevation. In comparison, during the incision stage there was a significant difference in diastolic pressure; however, other steps in the intervention were not significantly different between groups. Conclusion: We concluded that buccal infiltration injection without palatal injection can be an alternative technique instead of the conventional injection for MITMS.

• International Journal of Highway Engineering
• /
• v.15 no.4
• /
• pp.65-73
• /
• 2013

PURPOSES : As a research to develop a cement treated base course for an airport pavement which can enhance its drainage, this paper investigated the strength, infiltration performance and durability of the pervious concrete with respect to maximum coarse aggregate sizes and compaction methods. METHODS : This study measured compressive strength, infiltration rate, continuous porosity and freeze-thaw resistance of pervious concrete specimens, which were fabricated with five different compaction methods and different maximum aggregate sizes. In addition, in order to reduce the usage of Portland cement content and to enhance environment-friendliness, a portion of the cement was replaced with Ground Granulated Blast Furnace Slag (GGBS). RESULTS: Compressive strength requirement, 5 MPa at 7 days, was met for all applied compaction methods and aggregate sizes, except for the case of self-compaction. Infiltration rate became increased as the size of aggregate increased. The measured continuous porosities varied with the different compaction methods but the variation was not significant. When GGBS was incorporated, the strength requirement was successfully satisfied and the resistance to freezing-thawing was also superior to the required limit. CONCLUSIONS: The infiltration rate increased as the maximum size of aggregate increased but considering construct ability and supply of course aggregate, its size is recommended to be 25mm. With the suggested mix proportions, the developed pervious concrete is expected to successfully meet requirements for strength, drainage and durability for cement treated base or subbase course of an airport pavement.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.56 no.6
• /
• pp.85-91
• /
• 2014

In this study, the water quality purification of new medias which were NPS media, hyugato, mineral stone, charcoal for applying soil media of Integrated Management Practices (IMPs) of Low Impact Development (LID) were evaluated. The influent concentrations of COD, T-N, and T-P were 117.8 mg/L, 17.1 mg/L, and 2.062 mg/L, respectively. The infiltration capacities of NPS media, hyugoto, mineral stone, charcoal, and gravel were $7.1{\times}10m/s$, $7.3{\times}10^{-5}m/s$, $7.9{\times}10^{-5}m/s$, $6.0{\times}10^{-5}m/s$, respectively. All media meet criteria of infiltration capacity as surface soil layer at IMPs which is over $1.0{\times}10^{-5}m/s$. Maximum removal rates of COD, T-N, and T-P occurred at Charcoal with 98 % of COD removal rate, NPS with 78 % of T-N removal rate, and hyugato with 75 % fo T-P removal rate, respectively. For more high removal efficiency of all water quality item, the mixed media which is 4.5(NPS media): 1(charcoal) : 4.5 (hyugato) as volume ratio was evaluated. The infiltration capacity of mixed media was $7.9{\times}10^{-5}m/s$ and met the criteria of infiltration as surface soil layer. The water quality removal efficiencies of mixed media were very high with showing 70 % for COD, 85 % for T-N, and 71 % for T-P. The mixed media could purify the water quality of surface runoff and was recommended to used at the LID site of ground water quality problem.

• Journal of the Korean GEO-environmental Society
• /
• v.10 no.4
• /
• pp.5-13
• /
• 2009

The runoff-reducing facilities using infiltration was considered for the sustainable and sound water management. However, for practical utilization, many problems are attended and therefore effort on improvements are required. In this study, methods of improvement for infiltration facilities proposed by Infiltration-Storage System (ISS) and the effect of runoff reduction were analyzed by hydraulic experimental study. In order to analyze the infiltration characteristics of proposed runoff reduction facilities in this study, it was applied to various rainfall condition and surface material considering development and urbanization influences. As a results of hydraulic model experiment, Infiltration-Storage System (ISS) made addition to effect of reduction by lower layer of accumulative infiltration quantities. And then as rainfall-intensity was increased, accumulative infiltration rates were increased in this study. Thus, Infiltration-Storage system (ISS) was more efficient than existing runoff reduction facilities because of increasing infiltration rate. Such a result was guaranteed application of ISS as runoff-reducing facilities. Therefore, ISS is expected to be capable for practical application if subsequent research for improvements are followed. Additionally, results of this study are expected to provide fundamental research data on infiltration facilities.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.4 no.4
• /
• pp.3-11
• /
• 2001

To know the seawater infiltration into tidal flat sediment in coastal area is very important, because it is significantly correlated with the infiltration and transportation of pollutants in soil, the supply of dissolved oxygen, nutrients and organic matter to benthic organisms for survival of benthic organisms and the seawater purification. So, we set up purpose to clarify the infiltration behavior of seawater by wave action in tidal flat, to clear the effects of slope of tidal flat and breaking wave height on seawater infiltration and to quantify the infiltration volume of seawater. For purpose, the seawater infiltration was studied with visualization method by using coloring tracer and transparent glass beads replaced as natural sediment in model tidal flat. Specific conclusions derived from this study are as follows. The semi-circular type infiltration of seawater by wave action into saturated sediment was a new infiltration behavior that was not considered in previous studies. The infiltration rate of seawater was increased with increasing of breaking wave height and slope of tidal flat. However, the effects of the slope was bigger than that of breaking wave height on seawater infiltration into tidal flat sediments. It was possible to calculate the infiltration volume of seawater by wave action in natural tidal flat sediment and in fields. Therefore, we can point out that wave action play an important role in the supply of dissolved oxygen, nutrients and organic matter to benthic organisms, transportation or diffusion of pollutants and seawater purification. So, we hope to be studied the supply of food to benthic organism, pollutant transport and seawater purification on the base of these results.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.6 no.4
• /
• pp.52-61
• /
• 2003

This study was carried out to analyze the effects of stormwater retention and infiltration pond on reduction of flood peak and volume in a experimentally developed ecological pond. The experimental site has 542$m^2$ watershed area, 1,310mm yearly-averaged rainfall. And the area of the retention pond is 60$m^2$, the maximum water depth is 0.5m, the maximum and average storage is 15$m^3$and 9.3$m^3$d. And the area of infiltration pond is 58$m^2$, and the water depth varies 0.2m~0.5m. The monitoring system consists of one rainfall gage, one Parshall flume and acoustic water level gage, two rectangular weirs and acoustic water level gage for discharge gaging, and one data recording unit. Data from ten storm events in total, three storm events in year 2000 and seven storm events in year 2001, were collected. From the data the evaporation rate was achieved with the water balance equation, and the result shows 5.0mm/day in average. The result from the analysis of the effects on reduction of flood peak and volume, is that 14% reduction of flood volume and 15% reduction of flood peak in retention pond and 49% reduction of flood volume in infiltration pond.

• Journal of Korean Society of Water and Wastewater
• /
• v.20 no.1
• /
• pp.53-62
• /
• 2006

This study was carried out to obtain quantities of infiltration, inflow and exfiltration on sewer pipes of three areas at a small city. From the results, the most investigated sewer pipes should be infiltrated by underground water and undetermined water. Flowrate commonly showed two peak at 6 to 8 a.m. and 6 to 9 p.m. and which may be influenced by the sewer flowrate with washing or bathing time. BOD/TN ratio of below 4.0 were inferior as compared with proper criteria 5.1. Infiltration/inflow rates of three areas were 21.7% and $0.08m^3/km$ of A, 12.4% and $0.015m^3/km$ of B, 22.4% and $0.021m^3/km$ of C, respectively. This indicates that infiltration/inflow rate of A was obviously greater than that of B and C. Also, these results show that we can conduct sewer maintenance in good order as A, C and B zone.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.3 no.3
• /
• pp.53-61
• /
• 1983

The Green-Ampt equation for infiltration has been intensively investigated by many researchers because of its simplicity and adequacy for fitting experimental data to theoretical one. The infiltration equation derived from the theory of two phase flow coincides with the Green-Ampt equation except the viscouse resistance correction factor. This approach clearly defines variables in the Green-Ampt equation and also encounters the effect of viscosity of two fluids. A new equation for infiltration into multilayered soil is derived from the theory of two phase flow and compared with conventional equation. The new equation shows lower infiltration rate than that of conventional one and it is believed that this caused from the inclusion of viscosity in the derivation.

• Journal of Korea Water Resources Association
• /
• v.35 no.5
• /
• pp.611-618
• /
• 2002

In order to investigate the performance of the infiltration collector well and its effect on the runoff reduction, real-time field measurements are carried out. Based on these field data measured at Seongnam, Osan and Cheongju sites, the runoff reduction volumes and the peaks-cut-rate are quantitatively analyzed and compared with the total rainfall amount, the 10min averaged and the 10min maximum rainfall intensity. This results show that the infiltration collector well is very effective to reduce the runoff in urban area, which gives environmentally the positive to supply ground waters. It is also presented that the infiltration collector well is able to reduce up to 70% of the runoff and 40~70% of peaks, compared to a general one.