• Journal of Environmental Health Sciences
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• v.29 no.1
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• pp.67-73
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• 2003

This study was carried out to characterize the behavior and sources of particulate trace metal in Daegu city. TSP (Total Suspended Particulate matter) was collected by filters on High Volume Air Sampler from the four areal (reference, residential, commercial, industrial area). The moult were analyzed by AAS after preliminary treatment. The average centration trend of trace metals contained in TSP was shown as follows : Fe > Cu > Pb > Mn > Ni > Cr > Cd. The trace metals showed the highest concentration in the industrial area. This study showed the seasonal variation of trace metals. Fe and Mn showed high concentration in spring, whereas Cr, Ni, Cd and Pb showed high concentration in winter. Also this study showed the regional variation of trace metals. The order of the average concentration of trace metals was : industrial > commercial > residential > reference area. Using Mn as a reference element, the enrichment factor analysis were used for identifying the trace element contributors. The enrichment factors of Cr, Fe < 10 were considered to have a significant dust and soil source and termed nonenriched. Pb, Cd, Cu >>10 were enriched and had a significant fraction which was contributed by anthropogenic sources.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.E2
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• pp.77-85
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• 2004

In order to investigate the scavenging property of airborne carbonaceous particles by precipitations, rainwater, snow sample, and total suspended particulate matter (TSP) were collected at a heavily industrialized urban site. Elemental carbon (EC) contents of both rainwater and snow water were deter-mined using elemental analysis system. EC concentrations in rain samples varied from 33.6 to 166.6 $\mu\textrm{g}$ L$^{-1}$ with an average 47.2 $\mu\textrm{g}$ L$^{-1}$ . On the other hand, those of snow samples in three times snow events were ranged from 122.4 to 293.3 $\mu\textrm{g}$ L$^{-1}$ . As might be expected, EC showed the significantly high scavenging rate at the initial rainfall. The average total carbon (TC) scavenging rate by washout mechanisms was 57.6% for five rainfall events. The scavenging rate of EC gradually increased in proportion to the increasing rainfall intensity and rainfall amount.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.738-740
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• 2003

A method for identifying the released region and time of Asian dust using the long-range inverse transport model that traces the wind field in the backward direction from positions where Asian dust was observed is described. Initial conditions for the inverse transport simulation were obtained from the time variation of the density distribution of the suspended particulate matter (SPM) in the air measured at various places in Japan. Based on a concentration of trajectories of the air mass computed by the inverse transport model, the source region of Asian dust clouds observed at meteorological stations in Japan on March 17 to 18, 2002 was estimated. As a result, it was found that dust particles were released at about 6h on March 15 in the neighborhood of Inner Mongolian Autonomous Region.

• Journal of Korean Society for Atmospheric Environment
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• v.15 no.1
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• pp.13-22
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• 1999

This study is carried out to investigate the chemical composition of atmospheric deposition in Cheju Island, Korea. For this purpose, dustfall matter samples are collected by dust jar from August, 1995 to July, 1996 at five sampling sites and total suspended particulate matters (TSP) and rain are also collected at one site from October, 1995 to July, 1996. All the samples collected are analyzed, and then the information of the 19 chemical species and deposition amount of each species is obtained. These data are used to determine the regional trends in dustfall chemistry and deposition, and compare the characteristics of chemical compositions between dustfall, TSP and rainwater.

• Environmental Engineering Research
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• v.21 no.3
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• pp.265-275
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• 2016

In this study, the microalga Neochloris oleoabundans was cultivated in a sustainable manner using diluted anaerobic digestate to produce biomass as a potential biofuel feedstock. Prior to microalgae cultivation, the anaerobic digestate was characterized and several pretreatment methods including hydrogen peroxide treatment, filtration, and supernatant extraction were investigated and their impact on the removal of suspended solids as well as other organic and inorganic matter was evaluated. It was found that the supernatant extraction was the most convenient pretreatment method and was used afterwards to prepare the nutrient media for microalgae cultivation. A bench-scale experiment was conducted using multiple dilutions of the supernatant and filtered anaerobic digestate in 16 mm round glass vials. The results indicated that the highest growth of the microalga N. oleoabundans was achieved with a total nitrogen concentration of 100 mg N/L in the 2.29% diluted supernatant in comparison to the filtered digestate and other dilutions.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1467-1472
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• 2003

Fouling of heat exchangers is generated by water-borne deposits, commonly known as foulants including particulate matter from the air, migrated corrosion produces; silt, clays, and sand suspended in water; organic contaminants; and boron based deposits in plants. This fouling is known to interfere with normal flow characteristics and reduce thermal efficiencies of heat exchangers. This paper focuses on fouling analyses for six heat exchangers of two primary systems in two nuclear power plants; the regenerative heat exchangers of the chemical and volume control system and the component cooling water heat exchangers of the component cooling water system. To analyze the fouling for heat exchangers, fouling factor was introduced based on the ASME O&M codes and TEMA standards. Based on the results of the fouling analyses, the present thermal performances and fouling levels for the six heat exchangers were predicted.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.559-562
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• 2001

There are many engineering applications that demand settling acceleration and volume reduction of fine solid suspensions. It is a matter to Improve the dredged soil thickening as well as the dewatering characteristic, because settling acceleration of dredged soil decreases the scale of industrial process and volume reduction of dredged soil decreases environmetal challenge to the disposal sites. Direct electric current induces the movement of fine solid particles suspended in water. Upon formation of a soil structure, the current further induces the movement of water and contaminant in the soil skeleton. Theses phenomena are known as electrokinetics. This study investigates the viability, of using the technique of electrokinetic dewatering to river dredged soil for settling acceleration and volume reduction. The aspect, such as sedimentation velocity, final volume and current variation are discussed.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.431.2-431.2
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• 2014

The dielectric breakdown voltage (DBV) is a measure of an insulating fluids ability to withstand a high electric field stress without breaking down. Conventionally, the presence of water or particulate matter in a dielectric fluid comprises the liquid's breakdown strength. However, the addition of magnetic nanoparticles (MNPs) in the base oil can increase the dielectric breakdown voltage of the fluid reversely, if the condition of the added particles in the fluid is in balance with that of keeping down the initiation and propagation of electrical streamers. In this study, we developed a mathematical model by a set of coupled, nonlinear equations using the COMSOL multiphysics finite element simulation suite and calculated the dielectrophoretic activity of magnetic nanoparticles suspended in the presence of electric field, which is the behavior responsible for enhancing the dielectric characteristics of transformer oil, in order to examine how the activity differ in a transformer oil-based magnetic fluid.

• 유체기계공업학회:학술대회논문집
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• 2005.12a
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• pp.273-277
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• 2005

The large particles of suspended matter in raw water can be removed by allowing them to settle out in a presedimentation basin. But there are smaller particles in almost all surface water and some groundwater that will not settle out within a reasonable time without some help to accelerate the process, In the coagulation and flocculation processes, nonsettleable solids are converted into large and heavier settleable solids by physical-chemical changes broght about by adding and mixing coagulant chemicals into the raw water. The object of this research was to improve corrective injection method for low dissolution liquid in the water treatment plant. A sort of chemical feed equipment are diaphram pump, flow control in combined magnetic flowmeter md control valve, roto dipper wheel system and tube pump. Particularly low dissolution liquid (Calcium Hydroxide) put in a bit by feed equipment, tube pump is very useful method for corrective injection method in the water treatment plant.

• Korean Journal of Ecology and Environment
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• v.38 no.spc
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• pp.58-61
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• 2005

Environmental polluting materials from road surface drainage are a significant nonpoint source influenced to the eutrophication of lake and ecosystems with a transport development in recent years. To elucidate the discharge characteristics, the changing patterns in concentrations of polluting materials such as suspended solid (SS), chemical oxygen demand (COD), nitrogenous and phosphorus nutrients in drainage waters, were investigated during rainfall. Load variation of COD concentration in drainage water samples was closely related to that of SS concentration. This indicates that SS contained a greater part of organic matter. A quite difference between the past pavement and the new well-drainage pavement system was observed in the concentrations of SS and COD in drainage waters. Appreciable concentrations of nitrite and nitrate were determined in drainage waters. The present results indicate that the drainage water from road surfaces is a significant nonpoint source, and that the well-drainage pavement system introduced to skid prevention has an effect on the decreases of pollutants.