• The Journal of Korean Academy of Prosthodontics
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• v.23 no.1
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• pp.13-37
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• 1985

Biocompatibility of dense synthetic hydroxylapatite is well known and the direct bond with adjacent bone developed. The purpose of this study was to evaluate the potential of clinical application of tooth ash for preservation of alveolar ridge. For this purpose the author performed an experimental implantation of the particulate and root form of both pure dense hydroxylapatite and tooth ash in alveolar sockets immediately after extraction. The pure dense hydroxylapatite was particulate form and root form made by Calciteck Inc. The tooth ash was prepared by incineration at $950^{\circ}C$, and the syrindrical form of the tooth ash was sintered and trimmed to fit the size of the each extraction socket of 10 mongrel dogs. After sugery the clinical, roentgenographical, and histological observation was carried out. The results obtained were as follows; 1. Clinical observation disclosed no dehiscence and exfoliation due to tissue rejection. 2. Vertical resorption of alveolar bone occurred in all experimental sockets as well as the control sites on the roentgenograph. 3. Osteoclastic activity appeared at the inner surfaces of the crestal alveolar bone on the 1st week but disappeared on the 2nd week. 4. There were macrophages in the particulate form on the 1st and 2nd week after surgery but no macrophages appered in the root form. S. New bone formation was developed from the bony wall of experimental sockets and grew to bond with the implant materials. In particulate form the new bone formation did not occur in central zone independently. 6. Tooth ash implant sites were covered with the newly formed bony trabeculation from third week, but Calcitite particles were covered with soft tissue. 7. Generally the healing occurred more rapidly in control sites than in implant sites.

• Journal of The Korean Society of Agricultural Engineers
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• v.51 no.2
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• pp.51-57
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• 2009

The purpose of this study was to investigate characteristics of behavior of nutrients such as TN (Total nitrogen), TDN (Total dissolved nitrogen), TP (Total phosphorus) TDP (Total dissolved phosphorous) in runoff water from a nonpoint source dominated watershed ($6.67\;km^2$). Regular and intensive flow measurement and water sampling were taken during two years (February 2002 to January 2004) in the Ingyeong River, a tributary of the Han River. The mean concentrations of nutrients during rainy days were significantly (p < 0.05) higher than those during dry days. The mean TDN/TN ratio in rainy days (95%) is almost identical to that in dry days (96%), but mean TDP/TP ratio in rainy days (24%) significantly decreased compared with that in dry days (66%), suggesting that dominant form of TP is shifted from dissolved form to particulate form. Accordingly, the measures (.eg. filter strips, cover crops) to reduce soil erosion for fallow upland in the rainy season should be taken to control particulate phosphorous.

• Particle and aerosol research
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• v.6 no.4
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• pp.173-183
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• 2010

The high temperature pleated filter bags which were used during this study were made of pleated nonwoven fabric of heat and acid resistant polysulfonate fibers which can withstand the heat up to $300^{\circ}C$ and have a filtration area which is 3 to 5 times larger than the conventional round filter bags. Cartridge module packed with 3 kind of the sulfur impregnated activated-carbon based sorbents were inserted in the inner of the pleated filter bag. This type of pleated filter bag was designed to remove not only the particulate matter but also the gaseous elemental mercury. The electrostatic precipitator part can enhance the particulate removal efficiency and reduce the pressure drop of the pleated filter bag by agglomerated particles to form a more porous dust layer on the surface of the pleated bag which is increased the filter bag cleaning efficiency. In addition, the most of particles are separated from the flue gas stream through the cyclone and the electrostatic precipitator part which were installed at the lower part and main body part of the convergence particulate collector, respectively. Thus reduce particulate loading of the high temperature pleated filter bags were applied in this study to analyze the removal characteristics of particulate matter and gaseous elemental mercury.

• Journal of Korea Multimedia Society
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• v.24 no.8
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• pp.1138-1148
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• 2021

In this study, we developed a 'shared-use mobility'-mounted local particulate matter monitoring terminal technology to measure the actual particulate matter concentration around me. As a mobile terminal device in the form of an IoT sensor platform, it is designed to be separated into a control module and a sensor module to minimize interference between sensors and to consider the optimal observation position of each sensor. As a result of the field test, it was confirmed that particulate matter was locally different depending on time and space even within the same area. In addition, it was confirmed that the concentration of particulate matter in the relevant section differed by up to 100 times compared to the surrounding area due to specific sources of particulate matter such as unpaved roads. In addition, we positively reviewed the applicability of the service in the real-time metaverse environment using this result. Through technological advancement and application of multiple shared-use mobilities, we expect to be able to provide new services for practical smart city air environment monitoring, such as localized particulate matter information, air pollution event information, and identification of causes of particulate matter.

• Aerospace Engineering and Technology
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• v.2 no.1
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• pp.80-88
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• 2003

The present analysis quantifies the particulate contamination of KOMPSAT-2 satellite until in orbit life. Assumptions are defined about integration and test conditions and durations, then a budget is drawn. As KOMPSAT-2 activities are carried out in good cleanliness conditions, the particulate contamination budgets for satellite and instrument surfaces at BOL is fair. To summarise, in the baseline launch conditions (class 10,000) the contribution of satellite AIT and launch activities adds 500 PPM to MSC and STA apertures (telescope mirrors ; front lens ; baffle), 20,000 PPM to MSC and STA outer surfaces, 14 000 PPM to plate-form horizontal surfaces, 1400 PPM to plate-form vertical surfaces, 1000 PPM to plate-form radiators and less than 300 PPM to solar arra.

• Environmental Engineering Research
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• v.19 no.3
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• pp.215-221
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• 2014

Nano-sized $TiO_2$ particles were produced by a premixed flame aerosol reactor, and they were immobilized on a mesh-type substrate in form of particulate film. The reactor made it possible maintaining the original particulate characteristics determined in the flame synthetic process. The particulate morphology and crystalline phase were not changed until the particulate were finally coated on the substrate, which resulted in the better performance of the photocatalytic conversion of the volatile organic compounds (VOCs) in the ultraviolet $(UV)-TiO_2$ system. In the flame aerosol reactor, the various specific surface areas and the anatase weight fractions of the synthesized particles were obtained by manipulating the parameters in the combustion process. The performance of the $TiO_2$ particulate films was evaluated for the destruction of the VOCs under the various UV irradiation conditions. The decomposition rates of benzene and formaldehyde under the irradiation of UV-C of 254 nm in wavelength were evaluated to check the performance of $TiO_2$ film layer to be applied in air quality control system.

• 한국연소학회:학술대회논문집
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• 2006.10a
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• pp.117-121
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• 2006

Non-thermal plasma technology has many applications in various areas. One of the applications is regenerating diesel particulate filter (DPF). DPF is a widely applied device to control the particulate emission of diesel engines. But it needs periodic removal of clogged soot for the smooth running of engine. Conventional high-temperature removal processes easily leads to the breakage of DPF. Herein, low-temperature plasma formed in a dielectric barrier discharge (DBD) reactor was used to form active oxidants such as ozone and nitrogen dioxide. Experimentally, the effects of discharge power and frequency on the performance of DBD reactor were studied. Two oxidants, $O_3$ and $NO_2$, were synthesized and used for incinerating soot in the used DPF. Performances of the two oxidants on the reduction of soot were compared, and it was found that $NO_2$ is more effective than $O_3$ for getting rid of soot

• Journal of the Korean Society of Environmental Restoration Technology
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• v.25 no.4
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• pp.15-31
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• 2022

The Green Purification Unit System (GPUS) is a green infrastructure facility applicable to the roadside to reduce particulate matter from road traffic. This study introduces two types of GPUS (type1 and type2) and assesses the performance and maintenance costs of each of them. The GPUS's performance analysis used the data collected in November 2021 after the installation of the GPUS type1 and type2 at the study site in Suwon. The changes in the particulate matter concentration near the GPUS were measured. The maintenance cost of GPUS type1 and type2 was assessed by calculating the initial installation cost and the management and repair cost after installation. The results of the performance analysis showed that the GPUS type1, which was manufactured by combining plants and electric dust collectors, had a superior particulate matter reduction performance. In particular, type1 produced a greater effect of particulate matter reduction in the time with a high concentration (50㎍/m³ or higher) of particulate matter due to the operation of electric dust collectors. GPUS type2, which was designed in the form of a plant wall without applying an electric dust collector, showed lower reduction performance than type1 but showed sufficiently improved performance compared to the existing band green area. Meanwhile, the GPUS type1 had three times higher costs for the initial installation than GPUS type2. In terms of costs for managing and repairing, it was evaluated that type1 would be slightly more costly than type2. Finally, this study discussed the applicability of two types of GPUS based on the result of the analysis of their particulate matter performance and maintenance cost at the same time. Since GPUS type2 has a cheaper cost than type1, it could be more economical. However, in the area suffering a high concentration of particulate matter, GPUS type1 would be more effective than type2. Therefore, the choice of GPUS types should rely on the status of particulate matter concentration in the area where GPUS is being installed.

• Journal of Environmental Science International
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• v.13 no.12
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• pp.1067-1078
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• 2004

Atmospheric particulate matters were collected by 8-stage non viable cascade impactor from October 2002 to August at Jeju City. Eight water-soluble ionic components $(Na^+,\;NH_{4}_{+},\;K^+,\;Ca{2+},\;Mg^{2+},\;CI^-,\;NO_{3}^-\;and\;SO_{4}^{2-})$ were analyzed by Ion Chromatography. The concentration of particulate matters and eight water-soluble ionic components were determined to investigate their size distributions. Particulate matters exhibited a tri-modal distribution with peak value around $0.9,\;4.0{\mu}m\;and\;9.5{\mu}m.$ In summer, the last peak value was lower than other season values likely due to particulate matter scavenged by rain water. Four ionic components $(Na^+,\;Ca^{2+},\;Mg^{2+}\;and\;CI^-)$ exhibited a bi-modal distribution in the coarse mode whereas three ionic components $(NH_{4}^+,\;K^+\;and\;SO_{4}^{2-})$ in the fine mode, with maximum peak value around $0.9{\mu}m.\;NO_{3}^-$ was found in both the coarse and the fine mode. The enrichment factor (E.F.) of each ionic components was calculated. Based upon E.F., it is considered that $Na^+,\;CI^-,\;and\;K^+$ in coarse paricle mode were delivered form oceanic source, but other components might have other source origins.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.100-101
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• 2004

Many researches in Korea have been performed to understand the pollution of stream waters by acid mine drainage. However, few studies have been conducted regarding the effect of particulate and colloidal fractions on the transport of trace metals. To estimate harmful effects of trace metals, it is important to evaluate the particulate and colloidal metals as well as dissolved metals, because particulate and colloidal fractions of trace metals play an important role in transport of trace metals and may adversely affect habitats and organisms in riverine system. Colloids are solids with effective diameters in size range from 0.001 $\mu$m to 1 $\mu$m. According to Jone et al. (1974), metals in surface water, like Al, Fe, and Mn, require filtration with pore-size membranes smaller than 0.45 $\mu$m to define dissolved concentrations. The main objective of this study is to understand the effects of particulate, colloidal, and truly dissolved fractions on the transport and fate of trace metals in acid mine drainage. This study was conducted for the Onjeong creek in the Uljin mine area. Sampling was carried out in 13 sites, spatially covering the area from mine dumps to the downstream Onjeong reservoir. To examine the metal partitioning between particulate, colloidal, and truly dissolved fraction, we used successive filtration techniques consisting of conventional method (using 0.45 $\mu$m membranes) and tangential-flow ultrafiltration (using 0.001 $\mu$mm membranes). Ultrafiltration may seperate much smaller particles from aqueous phase (Josephson, 1984; Hernandez and Stallard, 1988). The analysis of metals were performed by inductively coupled plasma - atomic emission spectrometer (ICP-AES: model Perkin Elmer OPTIMA3000XL). Anions such as SO$_4$, Cl and NO$_3$ were measured with ion chromatograph (IC: model Dionex 120). Sample analysis is still in progress. The preliminary data show that the studied creek is severely polluted by Al, Fe, Mn, Pb and Zn. Toward upstream sites with relatively lower pH, less than 50% of Al and Fe occur in the sorbed form on particles or colloids, whereas more than 80% of Al and Fe occur in the sorbed form in downstream sites or tributaries with relatively higher pH. Less than 30% of Zn is present in particle or colloidal forms in the whole range of creek. Truly dissolved fraction of trace metals is negatively correlated with pH. The Kd values for Al, Fe and Zn consistently increase with increasing pH and decrease with increasing particle concentration.