• Resources Recycling
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• v.9 no.6
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• pp.45-52
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• 2000

Generally, the residues of EAF's dusts treated by reduction process at high temperature are disposed. If the residues can be recycled as iron sources of EAF by upgrading their iron contents, it can be expected to reduce the amounts of disposed wastes and the environmental impacts. Reduction of EAF's dusts mixed with millscale was carried out in rotary hearth furnace to upgrade iron contents of reduction residues. Dusts should be reduced rapidly to protect from reoxidation of reduced iron residue which can be reoxidized at high temperature. In our experimental conditions, optimum reduction time was about 40min. and iron contents of the residues were increased with increasing mixing ratio of millscale and upgrade to 85% at 50%wt mixing ratio. Zinc and lead contents in residues were about 3% and 0.5% respectively. The residues reduced rapidly must be recycled in EAF because heavy metal elements in the residues can be extracted easily and contaminate air and water.

• Resources Recycling
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• v.33 no.1
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• pp.15-21
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• 2024

The demand for electric vehicles powered by lithium-ion batteries is continuously increasing. Recovery of valuable metals from waste lithium-ion batteries will be necessary in the future. This research investigated the effect of reaction temperature on the lithium recovery ratio from hydrogen reduction followed by water leaching from lithium-ion battery NCM-based cathode materials. As the reaction temperature increased, the weight loss ratio observed after initiation increased rapidly owing to hydrogen reduction of NiO and CoO; at the same time, the H₂O amount generated increased. Above 602 ℃, the anode materials Ni and Co were reduced and existed in the metallic phases. As the hydrogen reduction temperature was increased, the Li recovery ratio also increased; at 704 ℃ and above, the Li recovery ratio reached a maximum of approximately 92%. Therefore, it is expected that Li can be selectively recovered by hydrogen reduction as a waste lithium-ion battery pretreatment, and the residue can be reprocessed to efficiently separate and recover valuable metals.

• Current Research on Agriculture and Life Sciences
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• v.32 no.1
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• pp.1-9
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• 2014

In contrast to conventional microwaves, QRD (Quadratic Residue Diffusor) microwaves are a new energy-efficient technology that enhances the effect of sterilization based on changing the wavelength phase difference. Therefore, this study investigated the sterilization of wood using environmentally friendly and low energy consuming QRD microwaves. The results are as follows: for the QRD microwaves used in this study, the efficiency E = 5.75e0.32 S ($R^2$=0.908). Although the early water content was not constant, the average water content was 30.3% and after one week of natural drying, the water content was 22.6%, representing an average water content reduction of about 8%. When increasing the microwave level from 3 kW ~ 9 kW, the time taken for the temperature to increase was reduced. After the QRD microwave treatment, the wood samples showed no change in their flexural rigidity, compressive strength, or cleavage. The QRD microwave levels used in the experiments were 3, 5, 7, and 9 kW, where 9 kW was found to be the most efficient. Thus, for the purpose of eliminating nematodes and termites inside wood, a higher QRD microwave level was found to be more effective and energy efficient.

• Korean Chemical Engineering Research
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• v.61 no.2
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• pp.258-264
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• 2023

The greenhouse gas (GHG) emission assessment of kenaf pellet, produced from locally generated kenaf residues in South Korea, has been studied based on the EU RED-II methodology for calculating GHG impact of biomass fuels. Based on the production pathway of kenaf residue pellet and emission coefficients from EU JRC report, the life cycle GHG emission of kenaf residue pellet is assessed as 3.0 gCO₂eq/MJ_pellet and the life cycle GHG emission of electricity generated from kenaf residue pellet is assessed as 11.9 gCO₂eq/MJ when electrical efficiency of final conversion is 25%. The potential GHG emission reduction of electricity produced from kenaf pellet is 90.3% compared to the domestic electricity emission factor 42.8 kgCO₂eq/MWh. Also, the electricity produced from kenaf pellet can reduce at least 59.6% of GHG emission compared to the electricity produced from imported wood pellets.

• The Korean Journal of Pesticide Science
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• v.13 no.4
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• pp.232-240
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• 2009

The aim of this study was to determine the processing and reduction factors for ginseng and its commodities during ginseng processing to obtain information of pesticide residue in ginseng. For this study, azoxystrobin was used in two field containing 6 years old ginseng plants. Ginsengs were harvested and processed to obtain different commodities (Dried ginseng, red ginseng and ginseng water and alcohol extracts, red ginseng water and alcohol extracts) for pesticide analysis. The amount of residue levels from wonju and icheon for fresh ginseng were 0.05, $0.03\;mg\;kg^{-1}$ dried ginseng were 0.12, $0.14\;mg\;kg^{-1}$, red ginseng were both $0.05\;mg\;kg^{-1}$, ginseng alcohol extract were 0.28, $0.33\;mg\;kg^{-1}$, ginseng water extract were 0.22, $0.16\;mg\;kg^{-1}$, red ginseng alcohol extract were 0.31, $0.20\;mg\;kg^{-1}$ and red ginseng water extract were 0.09, $0.11\;mg\;kg^{-1}$ respectively. These data were under MRLs notified by KFDA. The processing factors for ginseng products were 3.25, 1.34, 7.84, 4.63, 6.15 and 2.56 respectively. The reduction factors for ginseng products were 1.19, 0.51, 3.41, 1.91, 2.74 and 1.00 respectively. These data showed increment during processing which could be due to concentration but considering water contents, residue levels were similar or decreased than the initial residue level during processing.

• Journal of the Korea Organic Resources Recycling Association
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• v.27 no.1
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• pp.65-75
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• 2019

The government is promoting recycling of waste resources through the enactment of Fundamental Law on Resource Circulation, the revision of the Wastes Control Act and zero-landfilling of untreated waste through improved processes such as recycling and diversification. As of 2015, the total amount of landfilled waste is 38,308 ton/day in Korea. The amount of landfilled waste from industrial sectors is 23,577 ton/day, accounting for 62 % of total landfilled waste. In the study, we investigated the characteristics of the thermal treatment residue among inorganic wastes and estimated the landfill reduction potential according to the relevant recycling criteria, which can go through recycling paths. As a result, it is estimated that about 5~42 % of the landfilled waste can be reduced in case mandatory recycling and landfill suppression policies such as recycling criteria for thermal processing residues and expansion of recycling obligation targets should be implemented. In order to minimize landfill disposal, it is necessary to expand the diversity of waste recycling type and the usage of recycled products.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.10 no.1
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• pp.1-6
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• 2004

Amount of residual ink solvent on the packaging materials from Korea, Japan and Europe was measured and compared. The amount of packaging materials from Korea was much higher than that of Japan and Europe. To reduce the residual amounts of ink solvent, aging condition of printed packaging materials including aging time and temperature was modified and evaluated. Aging with high temperature and short time ($60^{\circ}C$ and 24 hours) was more effective for reduction of residual amount of ink solvent than that with low temperature and long time. To find out change of reduction pattern of residual amount of solvent according to plastic packaging material, several monolayer and multilayer packaging materials were selected. Among the monolayer packaging materials, the amount of EVOH and PET was lower than that of polyolefin plastic film including PE and PP. PP/EVOH/PET among the selected multilayer film showed the lowest amount of residual ink solvent on food packaging materials. Result of this research revealed that the residual amount of ink solvent can be reduced by proper selection of aging condition with and by appropriate application of mutilayer plastic film.

• Applied Chemistry for Engineering
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• v.8 no.1
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• pp.16-22
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• 1997

When platinum wan impregnated on carbon by methanol, surfactant have an important effect on the stability of platinum colloid. As the increase of amounts of surfactant enhanced the stability of platinum colloid, the particle size of platinum on carbon was diminished. But, after heat treatment, residue of surfactant remained in electrode to decrease current density of oxygen reduction. To remove surfactant, as temperature of heat treatment enhanced, platinum particle was aggromerated and current density was decreased.

• Bulletin of the Korean Mathematical Society
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• v.57 no.2
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• pp.407-417
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• 2020

Let (R, m) be a d-dimensional Cohen-Macaulay local ring with infinite residue field. Let I be an ideal of R that has analytic spread ℓ(I) = d, satisfies the G_d condition, the weak Artin-Nagata property AN^-_d-2 and m is not an associated prime of R/I. In this paper, we show that if j₁(I) = λ(I/J) + λ[R/(J_d-1 :_RI+(J_d-2 :_RI+I):_R m^∞)] + 1, then I has almost minimal j-multiplicity, G(I) is Cohen-Macaulay and r_J(I) is at most 2, where J = (x₁, _…, x_d) is a general minimal reduction of I and J_i = (x₁, _…, x_i). In addition, the last theorem is in the spirit of a result of Sally who has studied the depth of associated graded rings and minimal reductions for m-primary ideals.

• Corrosion Science and Technology
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• v.6 no.6
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• pp.304-307
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• 2007

As to the reflection electrode of LCD (liquid crystal displays), silver-copper-gold alloy (hereafter, it is called as ACA (Ag98%, Cu1%, Au1%)) is an effective material of which weathering resistance can be improved more compared with pure silver. However, there is a problem that gold remains on the substrate as residues when ACA is etched in cerium ammonium nitrate solution or phosphoric acid. Gold can not be etched in these etchants as readily as the other two alloying elements. Gold residue has actually been removed physically by brushing etc. This procedure causes damage to the display elements. Another etchant of iodine/potassium iodide generally known as one of the gold etchants can not give precise etch pattern because of remarkable difference in etching rates among silver, copper and gold. The purpose of this research is to obtain a practical etchant for ACA alloy. The results are as follows. The cyanogen complex salt of gold generates when cyanide is used as the etchant, in which gold dissolves considerably. Oxygen reduction is important as the cathodic reaction in the dissolution of gold. A new etchant of sodium cyanide / potassium ferricyanide whose cathodic reduction is stronger than oxygen, can give precise etch patterns in ACA alloy swiftly at room temperature.