• Asian-Australasian Journal of Animal Sciences
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• v.24 no.12
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• pp.1757-1762
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• 2011

Aflatoxins are natural contaminants of poultry feeds and feed ingredients and cause liver damage, immunosuppression, reduction in performance and mortality in broilers. A number of studies have been carried out to study the effects of aflatoxin on feed conversion ratio in broilers. The results on feed conversion ratio of 10 research articles in broilers fed with aflatoxin from first day of age to six weeks of age were compiled and were subjected to meta-analysis. Chi-square test and $Tau^2$ (heterogeneity co-efficient) were applied to test for significance of heterogeneity of studies. To integrate results, fixed effect model by Inverse Variance method (IV method) was used when heterogeneity was insignificant and otherwise random effect model by DerSimonian and Laird Method (DL method) was used. The results of meta-analysis showed that the adverse effect of aflatoxin on feed conversion ratio at the end of first week was negligible, second week was medium and third to six weeks was very large.

• Economic and Environmental Geology
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• v.51 no.4
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• pp.359-370
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• 2018

The batch and column experiments were performed to overcome the limitation of the neutralization process using the $scCO_2$-water-recycled aggregate, reducing its treatment time to 3 hour. The waste cement mortar and two kinds of recycled aggregate were used for the experiment. In the extraction batch experiment, three different types of waste mortar were reacted with water and $scCO_2$ for 1 ~ 24 hour and the pH of extracted solution from the treated waste mortar was measured to determine the minimum reaction time maintaining below 9.8 of pH. The continuous column experiment was also performed to identify the pH reduction effect of the neutralization process for the massive recycled aggregate, considering the non-equilibrium reaction in the field. Thirty five gram of waste mortar was mixed with 70 mL of distilled water in a high pressurized stainless steel cell at 100 bar and $50^{\circ}C$ for 1 ~ 24 hour as the neutralization process. The dried waste mortar was mixed with water at 150 rpm for 10 min. and the pH of water was measured for 15 days. The XRD and TG/DTA analyses for the waste mortar before and after the reaction were performed to identify the mineralogical change during the neutralization process. The acryl column (16 cm in diameter, 1 m in length) was packed with 3 hour treated (or untreated) recycled aggregate and 220 liter of distilled water was flushed down into the column. The pH and $Ca^{2+}$ concentration of the effluent from the column were measured at the certain time interval. The pH of extracted water from 3 hour treated waste mortar (10 ~ 13 mm in diameter) maintained below 9.8 (the legal limit). From XRD and TG/DTA analyses, the amount of portlandite in the waste mortar decreased after the neutralization process but the calcite was created as the secondary mineral. From the column experiment, the pH of the effluent from the column packed with 3 hour treated recycled aggregate kept below 9.8 regardless of their sizes, identifying that the recycled aggregate with 3 hour $scCO_2$ treatment can be reused in real construction sites.

• Journal of ILASS-Korea
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• v.24 no.4
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• pp.178-184
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• 2019

Diesel engines have the advantages of higher thermal efficiency and lower CO2 emissions than gasoline engines, but have the disadvantages that particulate matter (PM) and nitrogen oxides (NOx) emissions are greater than those of gasoline engines. In particular, nitrogen oxides (NOx) emitted from diesel engines generates secondary ultrafine dust (PM2.5) through photochemical reactions in the atmosphere, which is fatal to humans. In order to reduce nitrogen oxides (NOx), pre-treatment systems such as EGR, post-treatment systems such as LNT and Urea SCR have been actively studied. The Urea SCR consists of an injection device injecting urea agent and a catalytic device for reducing nitrogen oxides (NOx). The nitrogen oxide (NOx) reduction performance varies greatly depending on the urea uniformity in the exhaust pipe. In this study, spray characteristics according to the spray hole structure were confirmed, and the influence of spray uniformity on spray characteristics was studied through engine evaluation.

• Journal of IKEEE
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• v.24 no.3
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• pp.821-827
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• 2020

In particular, vehicles with internal combustion engines of public transportation such as diesel and CNG buses are in urgent need of measures to reduce emissions as they have a long daily total mileage, long driving hours and a large number of vehicles. In this paper, the fuel consumption rate (km/kWh) was actually measured through road test of electric buses. Based on the measured values, CO₂ emissions from internal combustion engines and electric buses were calculated per bus. In addition to environmental improvement effects such as the expected reduction of carbon dioxide compared to CNG buses when replacing city buses with electric buses, additional effects were analyzed when the replacement of CNG buses is expanded to electric buses.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.6
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• pp.683-690
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• 2010

Renewable and unutilized energy (biogas power generation, wind power, solar, small hydro-power, sewage heat source, etc.) seems to be suitable to install for the sewage treatment facilities. There are 357 sewage treatment plants in 2007. 17 plants among these have been operating for self-supporting energy by using solar power, small hydro-power and biogas in 2008. Newly built sewage treatment plant of 96,000 $m^3$/day for a newtown is expected to get up to energy consumption of 10 GWh/yr. If solar energy, small hydro-power and biogas-equipments were applied to the new treatment plant, self-supporting energy of the new sewage treatment plant will get up to 56.1%. As a results, about 2,379ton $CO_2$/yr $CO_2$ emission reduction can be expected by using renewable energy. These efforts for self-supporting energy will lead sewage treatment plant to new energy recycle center.

• Clean Technology
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• v.24 no.2
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• pp.135-145
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• 2018

There are various activities for reduction of the greenhouse gasses (GHG) emission around the world. The countries agreed to submit their's individual plans to the United Nations and have operated programs related to the Climate Change, in addition, the enterprises have spontaneously been developed individual calculation methodologies of GHG emission. This paper aims at examining methods for calculating the effect of the reduction of environmental impact, being divided into three categories; international standard, country, enterprise. The reduction effects of environmental impact were compared by applying an existing product of the vehicle undercover and the uni-materialized product and being selected six calculation methods of environmental footprint. There are significant differences according to the evaluation methods of product environmental footprint (PEF) reduction. Main factors of differences are a gap in system boundary, a scope of data collection and the replacement amount standard of existing products. Stakeholders are unreliable in the results of PEF reduction because of the differences in results by each methodology. Therefore, it is necessary to disclose in detail the methodologies of calculating the PEF reduction that relevant people can easily understand, also to enable comparisons of the reduction results by developing the standardization of evaluation methods of PEF in the long term.

• YAKHAK HOEJI
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• v.24 no.2
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• pp.79-86
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• 1980

CO-intoxication is a serious problem in public health since the coal briquette has been used as one of fuels from 1950's. It has been discussed that the treatment with acetic acid vapor may be effective for CO-intoxication. This study was undertaken to investigate the action of acetic acid therapy, comparing with the spontaneous air treatment The acetic acid vapor was introduced to the blood combined with CO (in vivo and in vitro). The dissociation of COHb, the production of COHb, the levels of Hb and adrenaline and nor-adrenaline were measured. The effect of acetic acid vapor on dissociation of COHb was about 7-9% more effective than the spontaneous air treatment. The acetic acid vapor treatment for the dissociation of COHb was similar effect to the spontaneous air treatment. In an experiment of the combining CO gas with blood, the acetic acid vapor treatment was less effective in the production of COHb than that of spontaneous air treatment. Treatment with the acetic acid vapor to rabbit intoxicated with CO gas induced a little amount of Hb in blood comparing with the spontaneous air treatment. But, it is not a significant increment statistically. By the acetic acid vapor treatment after CO gas intoxication the adrenaline was increased and noradrenaline was decreased. With these results, it is assumed that the effect of acetic acid therapy on CO-gas intoxication would be caused by inductions of Hb and adrenaline and to be reduction of nor-adrenaline.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.3
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• pp.39-46
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• 2020

Carbonation is a deterioration which degrades structural and material performance by permitting CO₂ and corrosion of embedded steel. Service life evaluation through deterministic method is conventional, however the researches with probabilistic approach on service life considering loading and cold joint effect on carbonation have been performed very limitedly. In this study, probabilistic service life evaluation was carried out through MCS (Monte Carlo Simulation) which adopted random variables such as cover depth, CO₂ diffusion coefficient, exterior CO₂ concentration, and internal carbonatable materials. Probabilistic service life was derived by changing mean value and COV (Coefficient of variation) from 100 % to 300 % and 0.1 ~ 0.2, respectively. From the analysis, maximum reduction ratio (47.7%) and minimum reduction ratio (11.4%) of service life were obtained in cover depth and diffusion coefficient, respectively. In the loading conditions of 30~60% for compressive and tensile stress, GGBFS concrete was effective to reduce cold joint effect on carbonation. In the tensile condition, service life decreased linearly regardless of material types. Additionally service life rapidly decreased due to micro crack propagation in the all cases when 60% loading was considered in compressive condition.

• Journal of Microbiology and Biotechnology
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• v.12 no.5
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• pp.849-853
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• 2002

Metal ions have an adverse effect on anaerobic digestion. In an acetate degradation test of upflow of anaerobic sludge blanket granules with $Cu^{2+}$, not all of the acetate that disappeared was stoichiometrically converted to methane. In the presence of 400 mg/g-VSS (volatile suspended solids) $Cu^{2+}$, only 26% of the acetate consumed was converted to methane. To study acetate conversion by other anaerobic microorganisms, sulfate and nitrate reductions were investigated in the presence of $Cu^{2+}$ Sulfate and nitrate reductions exhibited more resistance to $Cu^{2+}$than methanogenesis, and the granules reduced 2.2 mM and 5.4 mM of nitrate and sulfate, respectively, in the presence of 400 mg/g-VSS copper ion. However, the acetate degraded by sulfate and nitrate reductions was only 24% of the missing acetate that could have been stoichiometrically converted to $CO_2$. Accordingly, 76% of the acetate consumed appeared to have been converted to other unknown compounds.

• Resources Recycling
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• v.24 no.4
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• pp.32-37
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• 2015

Cobalt is abundant only in some countries including Democratic Republic of the Congo. It would be necessary to secure overseas Co ores and Co extraction technology. Two kinds of matte varying the sulfur content were manufactured by smelting reduction of Co concentrate containing ~8 wt% Co, ~19 wt% Cu, and ~3 wt% Fe. The amount of Co, Cu and Fe was concentrated to 19~21 wt%, 39~41 wt%, and 7~9 wt% respectively in the resulting matte. High-pressure leaching of matte was performed in an autoclave with considering the effect of oxidizing agent, $H_2SO_4$ concentration as a lixiviant, and the amount of sulfur added to the matte. An oxidizing agent (oxygen) is necessary to improve Co leaching efficiency enabling usage of a dilute $H_2SO_4$ leaching agent. An increase in $H_2SO_4$ concentration prevents selective leaching of Co, and the sulfur content in matte has a minor influence on the Co leaching efficiency.