• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.4
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• pp.229-235
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• 2018

In this study, recycled aggregate and natural aggregate were mixed in advance using an aggregate mixing facility that was developed to improve the quality of recycled aggregate concrete. Then the mixed aggregate was applied and concrete characteristics before and after a mix were considered. Based on the findings extracted, this study aimed to suggest a new direction for quality stabilization and application activation of recycled aggregate. The test results of change rates of mortars and coarse aggregates in fresh concrete mixed by a concrete mixer, before and after mixing aggregates showed that the variations of the mortars and coarse aggregates in the concrete mixed with the aggregates beforehand were decreased than those in the concrete before mixing them. The variation of compressive strength and the mean compressive strength at the ages of 3 and 7 days showed similar results before and after the aggregates were mixed, and the strength at the age of 28 days before and after mixing them showed larger deviation than that at the ages of 3 and 7 days. The use of the mixed aggregates after mixing aggregates beforehand reduced the variation in strength and is believed that it is advantageous for long-age strength development. The above results show that the variations of coarse aggregates and compressive strength in the concrete using the mixed aggregates produced by mixing recycled aggregates and natural aggregates beforehand are reduced so it will be possible to produce the homogeneous concrete by mixing aggregates beforehand.

• Membrane Journal
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• v.31 no.3
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• pp.212-218
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• 2021

It is inevitable to generate incomplete combustion gases when mankind utilizes fossil fuels. From this point of view, gas separation process of combustion gas suggests the possibility of recycling CO gas. In this study, we fabricated a facilitated transport polymeric composite membrane for CO separation using AgBF₄ and HBF₄. The copolymer was synthesized via free-radical polymerization of poly(vinyl alcohol) (PVA) as a main chain and acrylic acid (AA) monomer as a side chain. The polymer synthesis was confirmed by FT-IR and the interactions of graft copolymer with AgBF₄, and HBF₄ were characterized by TEM. PVA-g-PAA graft copolymer membranes showed good channels for facilitated CO transport. In this perspective, we suggest the novel approach in CO separation membrane area via combination of grafting and facilitated transport.

• Journal of Animal Environmental Science
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• v.14 no.3
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• pp.167-174
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• 2008

This survey was conducted to investigate housing types of Korean native cattle and beef cattle farms in Korea. The farm sized over 50 heads of cattle, 7,433 farms were surveyed. Regarding housing types for Korean native cattle and beef cattle, litter barn, freestall, mooring+litter ground and others accounted for 87.1, 9.8, 3.0, and 2.9 %, respectively. Most of Korean native cattle and beef cattle farms (94.7%) used litter floor rather than scraper. As for roof types, slate, panel, iron plate, galvanized plate, colored iron plate and sunlight represented 32.2, 13.7, 12.2, 10.2, 9.7, and 8.9 %, respectively. Open side wall type and winch curtain were 55.6, and 47.6 %, respectively. Bigger farms seemed to used more winch curtain than open style. Utilization period of automatic feeder, waterer, electric facility, and cooling facility was 6.7, 8.0, 8.5, and 6.0 years, respectively.

• Journal of the Korea Organic Resources Recycling Association
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• v.6 no.2
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• pp.81-93
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• 1998

In order to estimate the an adequate application level for dry matter production of orchardgrass(Dactylis glomerata L.) were investigated in different application levels of food waste compost and mineral nitrogen in 3 cuttings per annum, and to evaluated the soil improving effect of food waste compost. Annual food waste compost and mineral nitrogen were applied at levels of 0, 10, 20, 40 and $60ton\;ha^{-1}$, and 0, 90, 180 and $270kg\;ha^{-1}$, respectively. Significantly higher dry matter yield of orchardgrass obtained were ranges of $8.92{\sim}9.70ton\;ha-1$ at levels of $180{\sim}270kg\;ha^{-1}\;yr^{-1}$ than that of other levels of mineral nitrogen. Relative yield of each cut to annual dry matter yield were 32.0% 49.2% and 18.8% for 1st cut, 2nd cut and 3rd cut in mineral nitrogen treatment. Significantly higher dry matter yield of orchardgrass obtained were ranges of $8.04{\sim}8.90ton\;ha^{-1}$ at levels of $20{\sim}60ton\;ha^{-1}\;yr^{-1}$ than that of other levels of food waste compost. The efficiency of dry matter production to application of mineral nitrogen(kg DM $kg^{-1}$ N) were 21.2, 19.0 and 15.6kg at levels of 90, 180 and $270kg\;ha^{-1}\;yr^{-1}$, respectively. Higher efficiency of dry matter Production obtained were 27.6~20.2 kg at levels of $90{\sim}180kg\;ha^{-1}$ of mineral nitrogen applied to $20ton\;ha^{-1}$ of food waste compost, it may due to accelerated mineralization by mineral nitrogen application. Highest efficiency of dry matter production to application of food waste compost (kg DM $ton^{-1}$ FWC) obtained was 71.0 kg at level of $40ton\;ha^{-1}\;yr^{-1}$. Maximum dry matter yield of orchardgrass obtained were $9.98ton\;ha^{-1}$ at limiting level of mineral nitrogen of $358.5kg\;ha^{-1}$ and $9.12ton\;ha^{-1}$ at limiting level of food waste compost of $49.3ton\;ha^{-1}$ per annum, respectively. Ranges of $20{\sim}49.3ton\;ha^{-1}$ of food waste compost and $180{\sim}358.5kg\;ha^{-1}$ of mineral nitrogen were estimated an adequate levels for increase in dry matter production, and to maintenance for orchardgrass pastures. Application of food waste compost was affected to improve the soil characteristics.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.9 no.3
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• pp.169-179
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• 2011

There are two types of nuclear reactors in Korea and they are PWR type and CANDU type. The safe management of the spent fuels from these reactors is very important factor to maintain the sustainable energy supply with nuclear power plant. In Korea, a reference disposal system for the spent fuels has been developed through a study on the direct disposal of the PWR and CANDU spent fuel. Recently, the research on the demonstration and the efficiency analyses of the disposal system has been performed to make the disposal system safer and more economic. PWR spent fuels which include a lot of reusable material can be considered being recycled and a study on the disposal of HLW from this recycling process is being performed. CANDU spent fuels are considered being disposed of directly in deep geological formation, since they have little reusable material. In this study, based on the Korean Reference spent fuel disposal System (KRS) which was to dispose of both PWR type and CANDU type, the more effective CANDU spent fuel disposal systems were developed. To do this, the disposal canister for CANDU spent fuels was modified to hold the storage basket for 60 bundles which is used in nuclear power plant. With these modified disposal canister concepts, the disposal concepts to meet the thermal requirement that the temperature of the buffer materials should not be over $100^{\circ}C$ were developed. These disposal concepts were reviewed and analyzed in terms of disposal effective factors which were thermal effectiveness, U-density, disposal area, excavation volume, material volume etc. and the most effective concept was proposed. The results of this study will be used in the development of various wastes disposal system together with the HLW wastes from the PWR spent fuel recycling process.

• Journal of the Korea Concrete Institute
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• v.16 no.1 s.79
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• pp.79-87
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• 2004

The qualify of lightweight aggregate made from waste PET bottle(WPLA) and the workability, the unit weight and strength property of concrete with WPLA were investigated for the purpose of recycling the waste PET bottles as lightweight concrete fine aggregate. This study indicated a good result that WPLA should be replaced with less than $50\%$ of natural fine aggregate. When WPLA was replaced with $50\%$ of natural fine aggregate, the specific gravity and water absorption of mixed fine aggregate were greatly reduced about 23 and $75\%$ respectively in comparison with those of river sand. The quality of WPLA affected on the properties of lightweight aggregate concrete. The workability of fresh concrete with WPLA(WPLAC) was improved with increasing the replacement ratio of WPLA and water cement ratio. Slump increasing ratio of the former showed about $45 {\~} 120\%$ because that a specific gravity of fine aggregate was decreased from 2.6 to 1.7. The unit weight of concrete with $75\%$ WPLA was decreased about $17\%$ in comparison with that of control concrete. Furthermore, the compressive strength of concrete with 25 and $50 \%$ WPLA at the age of 28 days increased higher than 30 MPa regardless with water cement ratio (W/C=45, 49 and $53\%$) of this study. Specific strength of concrete with $25\%$ WPLA, $15.11{\times}10^3 MPa{\cdot}m^3/kg$, was higher than that of contro concrete in water cement ratio of $49\%$. The compressive strength-splitting tensile strength ratio and compressive strength-modulus of elasticity ratio of WPLAC were similar to that of nomal lightweight aggregate concrete. This results showed a good estimation that WPLA will be able to recycled as a fine aggregate for lightweight concrete.

• Journal of the Korea Organic Resources Recycling Association
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• v.1 no.2
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• pp.275-286
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• 1993

This experiment was to study the effects of application rates of mineral N and cattle slurry on the dry matter yield of Orchardgrass grown in different cutting frequency. Annual rates of mineral N of 0($N_0$), 90kg($N_1$), 180kg($N_2$) and 270kg／ha($N_3$) in 3 cuttings, and 0($N_0$), 120kg($N_1$), 240($N_2$) and 360kg/ha($N_3$) were applied as urea in 4 cuttings. Cattle slurry applied at rates of $30m^3(S_1)$, $60m^3(S_2)$ and $90m^3/ha(S_3)$, suppling 90kg, 180kg and 240kg N/ha in 3 cuttings, and at rates of $40m^3(S_1)$, $80m^3(S_2)$ and $120m^3/ha(S_3)$, suppling 120kg, 240kg and 360kg N/ha in 4 cuttings, respectively. The results were summarized as follows; 1. Mineral N and cattle slurry application rates(N), and cuts(C) were significant differences at the 0.1% level(p<0.001), and 5% level(p<0.05) for the interaction of $N{\times}C$ in both cuttings. 2. The annual dry matter yields obtained were 8.8ton-10.1ton/ha at rates of $N_1-N_3$, and 7.1ton-9.5ton/ha at rates of $S_1-S_3$ in 3 cuttings. The annual dry matter yields obtained were 10.9ton-13.9ton/ha at rates of $N_1-N_3$, and 6.9ton-11.2ton/ha at rates of $S_1-S_3$ in 4 cuttings, respectively. 3. Relative efficiency of cattle slurry N for the dry matter production of Orchardgrass pasture as compared to mineral N were 91.4%(ranged from 72.2% to 109.7%) in 3 cuttings, and 75.1%(ranged from 48.3% to 107.9%) in 4 cuttings, respectively. 4. The annual cattle slurry application rates required to maintain highest dry matter yields were estimated to be 90m3/ha(270kg N/ha) and 80m3/ha(240kg N/kg) in 3 and 4cuttings.

• Journal of the Korea Organic Resources Recycling Association
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• v.2 no.2
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• pp.53-63
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• 1994

In order to investigate the effects of application rates of mineral N and cattle slurry on the dry matter yield of Reed canarygrass grown in different cutting frequency, was was cernpared for the efficiency of N utilization. Annual rates of mineral N and cattle slurry N of 0 (control), 90kg, 180kg, 270kg and 360kg/ha in 3 cuttings, 0, 120kg, 240kg, 360kg and 480kg/ha in 4 cuttings, and 0, 150kg, 300kg, 450kg and 600kg/ha were applied as urea and cattle slurry in 5 cuttings, respectively. The results were summarized as follows: 1. The annual dry matter yields were increased with application rates of mineral N and cattle slurry. The annual dry matter yields of mineral N obtained were 14.4 ton/ha(ranged from 10.46 ton to 16.91 ton/ha) in 3 cuttings, 13.88 ton/ha(ranged from 9.91 ton to 16.53 ton/ha) in 4 cuttings and 15.98 ton/ha(ranged from 12.0 ton to 18.25 ton/ha) in 5 cuttings. The annual dry matter yields of cattle slurry obtained were 12.14ton/ha(ranged from 8.92 ton to 11.79ton/ha) in 3 cuttings, 10.81ton/ha(ranged from 8.92 to 11.79 ton/ha) in 4 cuttings and 12.98ton/ha(ranged from 10.68 ton to 14.85ton/ha) in 5 cuttings. 2. Relative dry matter yield of cattle slurry as compared to mineral N were 84.3%, 77.9% and 81.2% in 3, 4 and 5 cuttings. 3. Average increase in dry matter production(kgDM/kgN) tended to decrease with application rates of mineral N and cattle slurry, and higher cutting frequencies. Average increase in dry matter production obtained were higher values at rates of 30kg/ha/cut in both of mineral N and cattle slurry. Average increase in dry matter production to mineral N were 23.9kg, 18.8kg and 15.2kgin 3, 4 and 5 cuttings, respectively. 4. Average increase in total nitrogen yield(kgTN/kgN) to mineral N obtained were 0.46kg at rates of 60kg/ha/cut in 3 cuttings, and 0.45kg and 0.40kg at rates of 30kg/ha/cut in 4 and 5 cuttings. 5. Average increase in dry matter production(kgDM/kgN) to cattle slurry obtained were 13.7kg and 19.5kg at rates of 30kg/ha/cut in 3 and 4 cuttings, and 9.7kg at rates of 60kg/ha/cut in 5 cuttings. 6. Average increase in total nitrogen yield(kgTN/kgN) to cattle slurry was not concern to the rates of application. Average increase in total nitrogen yield to cattle slurry obtained were 0.11kg, 0.20kg and 0.21kg in 3, 4 and 5 cuttings. 7. Relative average increase in dry matter production of cattle slurry as compared to mineral N were 33.1%, 52.1% and 50.0% in 3, 4 and 5 cuttings. Relative average increase in total nitrogen yield of cattle slurry as compared to mineral N were 28.9%, 51.3% and 55.3% in 3, 4 and 5 cuttings.

• Journal of the Korea Organic Resources Recycling Association
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• v.11 no.2
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• pp.55-65
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• 2003

The combined effect of bioaugmentation of dechlorinating bacterial cultures and addition of iron powder($Fe^0$ on reductive dechlorination of tetrachloroethylene(PCE) and other chlorinated ethylenes in a artificially contaminated soil slurry(60micromoles PCE/kg soil). Two different anaerobic bacterial cultures, a pure bacterial culture of Desulfitobacterium sp. strain Y-51 capable of dechlorinating PCE to cis-1,2-dechloroethylene(cis-DCE) and the other enrichment culture PE-1 capable of dechlorinating PCE completely to ethylene, were used for the bioaugmentation test. Both treatments introduced with the strain Y-51 and PE-1 culture (3mg dry cell weight/kg soil) showed conversion of PCE to cis-DCE within 40days. The treatments added with $Fe^0$(0.1-1.0%) alone to the soil slurry resulted in extended PCE dechlorination to ethylene and ethane and the dechlorination rate depended on the amount of $Fe^0$ added. The combined use of the bacterial cultures with $Fe^0$(0.1-1.0%)) showed the higher PCE dechlorination rate than the separated application and the pattern of PCE dechlorination and end-product formation was different from those of the separated application. When 0.1% of $Fe^0$ was added with the cultures, the treatments with the strain Y-51 and $Fe^0$ resulted in cis-DCE accumulation from PCE dechlorination, but the treatment with the enrichment culture and $Fe^0$ showed the more extended dechlorination via cis-DCE. These results suggested that the combined application of and the bactrial culture, specially the complete dechlorinating enrichment culture, is practically effective for bioremediation of PCE contaminated soil.

• Journal of the Korea Organic Resources Recycling Association
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• v.27 no.1
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• pp.39-48
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• 2019

Objective of this study was to evaluate an optimum biochar application rate and estimate the carbon sequestration based on the soil chemical properties and growth responses for biochar application during tomatoes cultivation. The treatments consisted of control as recommended application rates of fertilizers, 0.01%, 0.03%, 0.05%, and 0.07% of biochar application(w/w, biochar:soil). For effects of soil chemical properties, the $NO_3-N$contents in the soil were peaked at 9 days after transplanting. But there was not significant difference(p>0.05) among the treatments during cultivation periods. However, $NH_4-N$ contents in the biochar treatment were lower than the control until 14 days of transplanting. $P_2O_5$ contents in the biochar treatments were lower than that of the control until 19 days after transplanting except 0.01% of biochar application plot. $K_2O$ contents in soils treated with 0.01% and 0.03% of biochar were higher until 6 days after transplanting than that in the control. For N use efficiency of biochar application, it was observed that the 0.05% biochar application plot was highest among the treatments. The highest carbon sequestration was estimated at $2.83mg\;kg^{-1}$ for 0.03% of biochar application. However, it is considered that the optimum biochar application rate was 0.05% for tomato cultivation, considering the growth characteristics and yield components.