• Journal of the Korea Organic Resources Recycling Association
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• v.29 no.2
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• pp.31-38
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• 2021

The aim of this study is to evaluate the possibility of treating slaughterhouse by-products using microbial electrolysis cells (MECs). The diluted pig liver was fed to MEC reactors with the influent COD concentrations of 772, 1,222, and 1,431 mg/L, and the applied voltage were 0.3, 0.6, and 0.9 V. The highest methane production of 5.9 mL was obtained at the influent COD concentration of 1,431 mg/L and applied voltage of 0.9 V. In all tested conditions, COD removal rate was increased as the influent COD concentration increased with average removal rate of 62.3~81.1%. The maximum methane yield of 129~229 mL/g COD was obtained, which is approximately 80% of theoretical maximum value. It might be due to the bioelectrochemical reaction greatly increased the biodegradability of pig liver. Future research is required to improve the methane yield and digestibility through optimizing the reactor design and operating conditions.

• Applied Chemistry for Engineering
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• v.22 no.6
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• pp.617-622
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• 2011

Ozone-based advanced oxidation was applied for the treatment of anaerobic digestion effluent of livestock wastewater. Initial COD and color value were 930 mg/L and 0.04, respectively, and the 1/10-diluted wastewater was used for the study. The treatment characteristics were compared between the conventionally generated ozone ($105{\mu}m$) and microbubbled ozone ($13{\mu}m$). The use of microbubbled ozone improved the removal of chemical oxygen demand (COD) and color by 85% and 26%, respectively, compared with the conventionally bubbled ozone. The application of microbubbled $O_3/UV$, $O_3/H_2O_2$, $O_3/UV/H_2O_2$ combinations resulted in 5~10% higher color removal than ozone alone, which implies that the contribution of UV or $H_2O_2$ is not significant in color removal. On the other hand, COD removal could be increased two folds compared with ozone alone through $O_3/UV/H_2O_2$ combination. The contribution of $H_2O_2$ was bigger than UV for COD removal with microbubbled ozone. Due to the enhancement of dissolved ozone and radical activity, the microbubbling enabled us to additional COD removal even after stopping ozone supply in the presence of UV or $H_2O_2$.

• Journal of the Korean Electrochemical Society
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• v.25 no.1
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• pp.42-49
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• 2022

In this study, the surface protection film based on organic-inorganic composite is manufactured for suppressing lithium dendrite growth, and the film is applied on the surface of Li metal negative electrode for lithium metal batteries (LMBs). The film is consist of the polyvinylidene fluoride (PVDF) polymeric binder which has good mechanical strength and high electrochemical stability, and carbon black (Super-P) which has outstanding electrical conductivity as the inorganic compound. First, in order to confirm the suppression of the internal short circuit by the lithium dendrite, the time required for the short circuit is measured while a constant current is continuously applied. As a result, the internal short circuit is delayed in proportion to the carbon black content of the film, and it is significantly delayed than bare Li metal electrode which does not use protection film. The cycle performance of the thick protection film (8 ㎛), is worse than that of the thin film (4 ㎛). However, as the carbon black content of the film increased, the cycle performance is improved. Thus, the surface protection film based on carbon black/PVDF composite can delay the internal short circuit, and has low overvoltage during the cycle. However, more stable cycle performance needs to be built through further improvements.

• Journal of Korean Society of Forest Science
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• v.111 no.4
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• pp.538-547
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• 2022

In this study, the population and community structure of Berchemia berchemiaefolia stands located at Mt. Naeyon (Gyeongbuk, Korea) were quantified, and multivariate analysis was done to determine the correlations between vegetation group types and environmental factors and to have reference data for the conservation and restoration of this species. In total, there were 164 B. berchemiaefolia trees in Mt. Naeyon. The average DBH of the trees was 24.5 cm, forming a normal distribution. It rarely appeared in an understory vegetation height of 3 m. About37.1% of the trees were branched. B. berchemiaefolia stands were classified into two groups: B. berchemiaefolia-Quercus serrata community and B. berchemiaefolia-Carpinus laxiflora community. Canopy gap, organic matter, exchangeable Ca, and cation exchange capacity were the major site characteristics affecting the distribution pattern of the stands. Currently, B. berchemiaefolia trees dominate in Mt. Naeyon, but depending on different habitat positions, the species was in a natural successional stage to C. laxiflora or C. cordata, which is a shade-tolerant species.

• Journal of the Korea Organic Resources Recycling Association
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• v.29 no.4
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• pp.33-40
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• 2021

In this study, the physico-chemical and biological characteristics of anaerobic granular sludge at different heights of a full-scale UASB reactor (UASBr) were investigated. Granular sludge was taken from 1 m, 2 m, and 3 m above the ground level in the UASBr. The morphological analysis showed that the upper part had bigger granules and the lower part had rounder granules. The ANOVA test confirmed that the mean size and the roundness of the granules had statistically significant difference along the height at 95% confidence level, and there was a significant negative linear relationship between the size and roundness (r=-0.40, p<0.05). A SMA test using acetic, propionic and butyric acids showed that granules from 2 m height had the highest specific methanogenic activity. The EPS contents were also unequal to each height, with 2 m showing the highest content. These findings could be helpful to understand the different characteristics of stratified anaerobic granules in full-scale UASBr and maintain the reactor performance.

• Journal of the Korea Organic Resources Recycling Association
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• v.29 no.4
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• pp.5-13
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• 2021

Ammonia, primarily originating from urinary urea of the livestock manure, is known to play as a major precursor of fine particulate matter (PM2.5) generation which leads to a decrease in air quality and to harmful effects on public health. The objective of this study was to evaluate the effect of acetohydroxamic acid (AHA) addition on inhibition of ammonia conversion from urea. The experiment was performed at different urea concentration (500-4,000 mg Urea-N/L), AHA concentration (0-4,000 mg AHA/L), pHs (pH 6-10), and temperature (10-35℃). The result showed that the urease inhibition efficiency increased at higher concentration of AHA. However, the specific urease inhibition activity decreased at higher pH, showing 867.1±6.7 Unit/g AHA at pH 6 and 1,167.9±17.4 Unit/g AHA at pH 10, respectively. Decreased urease inhibition efficiency at both AHA and control was observed at higher temperature. This finding indicates that AHA can be used as the urease inhibitor for reducing ammonia emission in the management of livestock manure.

• Journal of the Korean GEO-environmental Society
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• v.23 no.3
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• pp.23-29
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• 2022

In this study, we investigated the ozone nanobubble process in which nanobubble and ultrasonic cavitation were applied simultaneously to improve the dissolution and self-decomposition of ozone. To confirm the organic decomposition efficiency of the process, a 200 mm × 200 mm × 300 mm scale reactor was designed and phenol decomposition experiments were conducted. The use of nanobubble was 2.07 times higher than the conventional ozone aeration in the 60 minutes reaction and effectively improved the dissolution efficiency of ozone. Ultrasonic irradiation increased phenol degradation by 36% with nanobubbles, and dissolved ozone concentration was lowered due to the promotion of ozone self-decomposition. The higher the ultrasonic power was, the higher the phenol degradation efficiency. The decomposition efficiency of phenol was the highest at 132 kHz. The ozone nanobubble process showed better decomposition efficiency at high pH like conventional ozone processes but achieved 100% decomposition of phenol after 60 minutes reaction even at neutral conditions. The effect by pH was less than that of the conventional ozone process because of self-decomposition promotion. To confirm the change in bubble properties by ultrasonic irradiation, a Zetasizer was used to measure the bubbles' size and zeta potential analysis. Ultrasonic irradiation reduced the average size of the bubbles by 11% and strengthened the negative charge of the bubble surface, positively affecting the gas transfer of the ozone nanobubble and the efficiency of the radical production.

• Journal of Mushroom
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• v.21 no.3
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• pp.118-125
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• 2023

We conducted an on-site application study at the livestock cooperative fertilizer plant to compare the composting period, temperature change, moisture content, and chemical properties between livestock manure compost using sawdust as a moisture regulator with those using spent oyster mushroom substrate. The composting period, moisture content, and fertilizer composition of compost containing spent oyster mushroom substrate did not differ from that of conventional compost mixed with sawdust after the first and second fermentation and post-maturation stages, it was suitable as a material for manufacturing livestock manure compost. The spent oyster mushroom substrate also lower the production cost of livestock manure compost by replacing the more expensive sawdust. The developed technology is expected to contribute towards the utilization of by-products of the oyster mushroom harvest while simultaneously producing high quality livestock manure compost.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.3
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• pp.27-34
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• 2023

In this study, various plant-based biomass are recycled into carbon materials to employ as anode materials for lithium-ion batteries. Firstly, various biomass of rice husk, chestnut, tea bag, and coffee ground are collected, washed, and ground. The carbonization process is followed under a nitrogen atmosphere at 850℃. The morphological and chemical properties of materials are investigated using FE-SEM, EDS, and FT-IR to compare the characteristic differences between various biomass. It is noticeable that biomass-derived carbon materials vary in shape and degree of carbonization depending on their precursor materials. These materials are applied as anode materials to measure the electrochemical performance. The specific capacities of rice husk-, chetnut-, tea bag-, and coffee ground-derived carbon materials are evaluated as 65.8, 80.2, 90.6, and 104.7 mAh g^-1 at 0.2C. Notably, coffee ground-based carbon exhibited the highest specific capacity owing to the difference in elemental composition and the degree of carbonization. Conclusively, this study suggests the possibility of utilizing as energy storage devices by employing various plant-based biomass into active materials for anodes.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.6
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• pp.681-692
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• 2017

In recent years, large-scale construction projects such as road pavement construction and new city construction have been carried out nationwide with by the expansion of social overhead facilities and base on the economic development planning, resulting in a rapid increase in artificial slope damage. The existing vegetation-based re-installation method of the slope surface greening method reveals various problems such as lack of bonding force, drying, and lack of organic matter. In this study, research was carried out using vegetation-based material and environmentally friendly soil additives, were are used in combination with natural humus, Bark compost, coco peat, and vermiculite. Uniaxial compressive strength was measured according to the mixing ratio of soil additives and the strength was analyzed. Experiments were carried out on the characteristics of the soil material to gauge the slope protection properties by using the soil compaction test method wherein the soil and the soil additive materials are mixed in relation to the soil height, the number of compaction, the compaction method (layer) and the curing condition. As a result of the experiment, excellent strength performance was demonstrated in soil additives using gypsum cement, and it satisfied vegetation growth standards by using performance enhancer and pH regulator. It was confirmed that the strength increases with the mixing of soil and soil additive, and the stability of slope protection can be improved.