• Asian-Australasian Journal of Animal Sciences
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• v.25 no.11
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• pp.1627-1633
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• 2012

This study was to evaluate the feasibility of recycling the solids separated from swine wastewater treatment process as a fuel source for heat production and to provide a data set on the gas emissions and combustion properties. Also, in this study, the heavy metals in ash content were analyzed for its possible use as a fertilizer. Proximate analysis of the solid recovered from the swine wastewater after flocculation with organic polymer showed high calorific (5,330.50 kcal/kg) and low moisture (15.38%) content, indicating that the solid separated from swine wastewater can be used as an alternative fuel source. CO and NOx emissions were found to increase with increasing temperature. Combustion efficiency of the solids was found to be stable (95 to 98%) with varied temperatures. Thermogravimetry (TG) and differential thermal analysis (DTA) showed five thermal effects (four exothermic and one endothermic), and these effects were distinguished in three stages, water evaporation, heterogeneous combustion of hydrocarbons and decomposition reaction. Based on the calorific value and combustion stability results, solid separated from swine manure can be used as an alternative source of fuel, however further research is still warranted regarding regulation of CO and NOx emissions. Furthermore, the heavy metal content in ash was below the legal limits required for its usage as fertilizer.

• Journal of the Korean Wood Science and Technology
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• v.25 no.1
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• pp.37-41
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• 1997

Hot-water soluble extracts were prepared from medium-sized barks of Siberian larch (Larix gmelineii). The extracts were fractionated by ultrafiltration method for producing uniform quality of adhesives. Molecular weight distribution of the extracts was ranged of 100 to 300.000. pH of the extracts affected amounts of flux, and the range of pH 6~pH 8 was proper for wood adhesives, because of easy concentration and fast gelation time. Removal of particles greater than $0.45{\mu}m$ from the extracts increased both filtration speed (flux) and yields of solids in the filtrates. In ultrafiltration process. operating pressure, filtrate temperature, and flow rate significantly increased with the increase of individual condition. Ultrafiltration using PM10 membrane was very effective to fractionate and concentrate the extracts. Removal of large particles greater than 0.45 m from the extracts increased filtration speed(flux) and yields of solids in the filtrates. A gelation time was accelerated with the increasing pH of the extracts and its concentration. The Stiasny precipitate(26%) from the filtrate obtained by PM 10 membrane was very lower than that(78%) of the retentates. This ultrafiltration method was efficient for obtaining high yield purified phenolic compounds.

• Journal of Environmental Science International
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• v.31 no.4
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• pp.341-356
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• 2022

Electrical Conductivity (EC) or Total Dissolved Solids (TDS) has been often used to evaluate the water quality in some water education program for children and youth. This study attempted to find out whether EC (or TDS) can be used as a water pollution criteria in water education program. To clarify it, we used the water analysis data of July 2019 and January 2020 from Water Environment Information System. Data from 332 points in Han-river were used to investigate correlation between the parameters, such as BOD, COD, TN, TP vs EC. Correlation(r) for all data of BOD vs. EC was 0.347 for July 2019 and 0.483 for January 2020. No correlation was observed for BOD Ia and BOD Ib for July 2019 (r=-0.041, -0.030, respectively) and BOD Ia for January 2020 (r=0.041). Better correlation for all data of COD vs. EC was obtained (r=0.543 for July 2019 and r=0.610 for January 2020). However, no correlation was observed for COD Ia for January 2020. High vlaue of EC or TDS does not always mean water pollution, especially for clean water environment. Thus, EC (or TDS) alone can not be used as a water pollution criteria.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.457-460
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• 2003

This paper discusses laboratory evaluations to assess the physical properties of antiwashout underwater concrete (AWC) containing pozzolanic materials such as fly ash (FA), blast furnace slag (SG) and metakaolin(MK). For the experiments, pH value, suspended solids, slump flow, efflux time and compressive strength were tested. According to the results from compressive strength test, MK10 showed the very high compressive strength characteristic during the entire curing days, but the rate of strength development was decreased as time goes by.

• Journal of the Korean Professional Engineers Association
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• v.45 no.2
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• pp.44-47
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• 2012

The water is very important resource that we can maintain our life and get the high-quality energy. The water begins with creation of the earth and circulates in the atmosphere, ocean, surface and subsurface in the form gases, liquids and solids. Human has used the water in abundance, however we have polluted water irresponsibly and discharged wastewater into the earth. We must think, how long does areas, pollution, pollution treatment, produce. Consider together about the water shock will occur when in any form.

• Bulletin of the Korean Chemical Society
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• v.8 no.3
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• pp.183-185
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• 1987

1-Methylimidazolium chlorochromate was prepared by the addition of 1-methylimidazole into a solution of chromic trioxide in 6M hydrochloric acid and obtained in high yield as bright yellow crystalline solids. The reagent was found to be very effective for the oxidation of alcohols and the oxidative cleavage of oximes to the corresponding carbonyl compounds.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.1
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• pp.93-100
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• 2005

Comparative thickening and dewatering characteristics of municipal wastewater sludge were investigated in terms of separated and combined treatment of primary and secondary BNR sludge. Also, various conditioning methods such as cation polymer addition, steam and ultrasonication treatment were examined to improve dewaterability of sludge. The dewaterability was measured by using specific resistant test, wedge zone simulator and centrifuge. The result of the sludge thickening test revealed that separated thickening was better in terms of solids recovery and supernatant quality. Particularly, the thickening of primary sludge with high solids (about 3.5% TS) showed very poor solid separation. The addition of cation polymer showed better conditioning characteristic for dewatering and the optimal polymer dosage was 0.26% for primary sludge, 0.43% for secondary sludge and 0.38% for combined sludge. Contrary to the result of the thickening, the dewatering test revealed that dewatering of the combined sludge is better than that of separated sludge, representing better solids separation and filtrate quality. The polymer addition was essential to improve dewaterability in filter (belt) press type dewatering but it was inefficient for the dewatering of secondary sludge only. The centrifuge type dewatering showed better performance and the dewaterability was slightly improved when the polymer was added. Based on the results of this research a sustainable sludge treatment process, particularly in terms of the recycle water quality and solids recovery, was proposed.

• Korean Chemical Engineering Research
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• v.52 no.1
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• pp.81-87
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• 2014

Flow characteristics and the operating range of gas velocity was investigated for a two-stage bubbling fluidized-bed (0.1 m-i.d., 1.2 m-high) that had continuous solids feed and discharge. Solids were fed in to the upper fluidized-bed and overflowed into the bed section of the lower fluidized-bed through a standpipe (0.025 m-i.d.). The standpipe was simply a dense solids bed with no mechanical or non-mechanical valves. The solids overflowed the lower bed for discharge. The fluidizing gas was fed to the lower fluidized-bed and the exit gas was also used to fluidize the upper bed. Air was used as fluidizing gas and mixture of coarse (< $1000{\mu}m$ in diameter and $3090kg/m^3$ in apparent density) and fine (< $100{\mu}m$ in diameter and $4400kg/m^3$ in apparent density) particles were used as bed materials. The proportion of fine particles was employed as the experimental variable. The gas velocity of the lower fluidized-bed was defined as collapse velocity in the condition that the standpipe was emptied by upflow gas bypassing from the lower fluidized-bed. It could be used as the maximum operating velocity of the present process. The collapse velocity decreased after an initial increase as the proportion of fine particles increased. The maximum took place at the proportion of fine particles 30%. The trend of the collapse velocity was similar with that of standpipe pressure drop. The collapse velocity was expressed as a function of bulk density of particles and voidage of static bed. It increased with an increase of bulk density, however, decreased with an increase of voidage of static bed.

• Journal of Korea Water Resources Association
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• v.46 no.11
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• pp.1115-1128
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• 2013

The purpose of this study is to evaluate the suspended solids and eutrophication processes relationships in Chungju lake using CE-QUAL-W2, two-dimensional (2D) longitudinal/vertical hydrodynamic and water quality model. For water quality modeling, the lake segmentation was configured as 7 branches system according to their shape and tributary distribution. The model was calibrated (2010) and validated (2008) using 2 years of field data of water temperature, suspended solids (SS), total nitrogen (TN), total phosphorus (TP) and algae (Chl-a). The water temperature began to increase in depth from April and the stratification occurred at about 10 m early July heavy rain. The high SS concentration of the interflow density currents entering from the watershed was well simulated especially for July 2008 heavy rainfall event. The simulated concentration range of TN and TP was acceptable, but the errors might occur form the poor reflection for sedimentation velocity of nitrogen component and adsorption-sediment of phosphorus in model. The concentration of Chl-a was simulated well with the algal growth patterns in summer of 2010 and 2008, but the error of under estimation may come from the use of width-averaged velocity and concentration, not considering the actual to one side inclination by wind effect.

• Food Science and Preservation
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• v.14 no.6
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• pp.565-570
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• 2007

Changes in the quality of Hallabong tangor during growth stage and with temperature pre-treatment after harvest were investigated. Soluble solids of Hallabong increased continuously until early December. The acid content of M16A, a variant species of Hallabong, decreased by 1% after October and continued to decrease until the middle of January. After ripening, treatment to reduce the acid content was required. Fruit firmness decreased gradually until November and was maintained at 1000 g-force after this time. Soluble solids and acid content were $13.3{\pm}0.83^{\circ}Brix$ and $1.07{\pm}0.52%$. Soluble solids increased in temperature-treated Hallabong with prolonged storage, but acid content did not decrease. Fruit firmness also decreased with storage period, regardless of temperature pre-treatment. Therefore, water management during cultivation, temperature treatment above $35^{\circ}C$ after harvest, and checking of the acid content and soluble solids with prolonged storage are recommended in achieving high quality Hallabong.