• Journal of the Korean Wood Science and Technology
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• v.27 no.3
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• pp.51-62
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• 1999

The objective of this research is to develop paper sludge reinforced thermoplastic composites which incorporate the advantages of each component materials. The effects of paper sludge content(0, 10, 20, 30, 40----), mesh size(20~40, 60~80, less than 100mesh), and coupling agent(Epolene E-43 and Epolene G-3003) on the mechanical properties of paper sludge-polypropylene composites were investigated. Composite density increased with an increase in the paper sludge content. When paper sludge is incorporated into a polypropylene matrix, the flexural properties of the composite increase significantly with an increase in the paper sludge mixing ratio. Especially, flexural modulus was improved with increasing paper sludge content. The flexural strength of composites was improved, but flexural modulus reduced somewhat with decreasing paper sludge particle size. The flexural properties of paper sludge-polypropylene composites were improved by using coupling agents to enhance the bonding between reinforcing filler and matrix. Use of the epolene E-43 and G-3003 resulted in considerable improvement in the flexural strength over control specimens. The flexural strength of the G-3003 composite system is higher than that of the E-43 system. Generally, izod notched impact strength of paper sludge-polypropylene composite decreased slightly, whereas izod unnotched impact strength decreased significantly with increasing paper sludge contents. There was no effects of paper sludge particle size on impact strength of paper sludge-polypropylene composites. And izod unnotched impact strength of epolene E-43 composite system sharply decreased but that of G-3003 composite system was no tendency with increasing additive content.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.9
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• pp.870-878
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• 2010

We investigated the concentration and the sources of ubiquitous persistent organic pollutants [i.e., 17 toxic polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), 12 coplanar polychlorinated biphenyls (Co-PCBs), and 16 priority polycyclic aromatic hydrocarbons (PAHs)] in waste papers and lumbers from industrial complexes. The total concentrations in waste papers and lumbers ranged from 9.69~176.77 pg/g-dry and 0.14~0.25 pg/g-dry for 17 PCDD/Fs, 109.95~4097.25 pg/g-dry and 28.23~59.88 pg/g-dry for 12 Co-PCBs and 9.30~52.18 ng/g-dry and 0.82~1.82 ng/g-dry for 16 PAHs respectively. Generally, the concentration of these pollutants in waste papers was higher than those in waste lumbers. OCDD was dominant in waste papers and lumbers and the PCDD/F patterns of these samples were similar with that of stack gas. The distribution patterns of Co-PCBs in wastes were related with commercial PCB products, indicating the effect of commercial PCB products on ubiquitous environment. The diagnostic ratios of several PAH compounds in waste paper showed that they were related with pyrogenic sources.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.789-792
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• 2008

Blast furnace slag doesn't have self-hydraulicity and it needs stimulants such as alkali to hydrate. Therefore using recycled aggregates erupted calcium hydroxides and blast furnace slag acquiring alkali stimulate could make a complementarily use of a recycling architectural material possible. In this study, we have discussed about characters of blast furnace slag and recycled aggregate firstly, and make recycled aggregate mortar and concrete using blast furnace slag for the experiment. The experiment is about mortar and concrete using recycled aggregate as a substitutional material of blast furnace slag. In this experiment, I replace blast furnace slag and aggregate with recycled aggregate. Conclusions through the test results analysis are as follows. And then, we added field experiment using concrete with composited materials.

• Journal of the Korean GEO-environmental Society
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• v.11 no.3
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• pp.33-41
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• 2010

The rammed aggregate compaction pile method is widely used as soft ground improvement method because of the installed piles improve not only overall composite capacity but also discharge capacity. But the discharge capacity is declined when the clogging is generated due to the clay penetration into voids of rammed aggregate compaction pile with the time elapsed. The purpose of this study is to reduce the clogging problem occurred in rammed aggregate compaction pile constructed in the soft ground and to minimize voids of rammed aggregate compaction pile. The proper mixing ratio was determined which is based on the results of the large scale direct shear tests conducted to get strength and permeability as optimum mixing ratio of crushed stone and bottom ash. The test results indicated that the highest internal friction angle was obtained at 80:20 mixing ratio of crushed stone and bottom ash. The internal friction angle was declined when the mixing ratio of the bottom ash increased over 20%. The results of the clogging tests, presented that the mixture of 80:20 crushed stone and bottom ash is highest effective of clogging than ratio of pure crushed stone.

• Resources Recycling
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• v.11 no.6
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• pp.3-11
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• 2002

Recently, waste printed circuit board (PCB) has significantly increased in its amount due to the rapid development of electronic industries. Since several kinds of noxious materials and also valuable metals are contained in it, the waste PCB is in an urgent need of recycling for the dual purposes for the prevention of environmental pollution and recovery of valuable resources. Also, the catalyst which equipped in the exhaust pipes of automobiles to reduce emission of air pollutants contains precious met-als so that their recovery from the waste auto-catalysts is required. In this study, the recovery of valuable metals from waste PCB and auto-catalyst by arc furnace melting process has been investigated, which is known to be very stable and suitable f3r less production of pollutants due to its high operating temperature. The effect of the kind of flux on the recovery of precious metals was examined by using quicklime, converter slag, and copper slag as the flux. In addition, the influence of direct and alternating current and the applying direction of direct current has been investigated. It was observed that using converter or copper slag as a flux was more desirable for a higher efficiency in the precious metal recovery compared with quicklime. For the effect of current, application of direct current taking the bottom as a negative pole generally showed a better efficiency for the extraction of valuable metals from waste PCB, which was also observed for the case of waste auto-catalyst. The average recovery of precious metals from both wastes by arc furnace melting process was very high, which was up to in the range of 95～97%.

• Food Science and Preservation
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• v.22 no.5
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• pp.714-720
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• 2015

Biji is a tofu by-product made by squeezing the liquid out of the dregs left over from making tofu. The objectives of this research were to break the biji into sub-micron-scale particles and to prepare a biji sub-micron suspension having increased quality characteristics such as antioxidant capacity, polyphenol, dietary fiber, and soluble protein contents, in comparison with untreated biji. Disruption of biji by an ultra-high-pressure homogenization (UHPH) process was used to prepare the sub-micron suspension of biji. UHPH can be used to prepare emulsions or suspensions with extremely small particle sizes. The effect of the UHPH process on biji was studied at 1,000, 1,500, and 2,000 bar. The extraction yield increased up to 1.64 times by breaking the biji to form a sub-micron suspension. The soluble dietary fiber, protein, and free amino acid contents were increased by the UHPH process (p<0.05), in comparison with those of untreated biji. Furthermore, the total sugar, free sugar, and total polyphenol contents of biji were augmented by the UHPH process. Antioxidant activity (ABTS) after exposure to UHPH (1,000-2,000 bar) was well retained (p<0.05). The extraction efficiencies and nutritive components were enhanced by increasing the pressure in the UHPH process.

• Journal of the Korea Concrete Institute
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• v.17 no.4 s.88
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• pp.499-504
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• 2005

Polymer concrete shows excellent mechanical properties and chemical resistance compared with conventional normal cement concrete. The polymer concrete Is drawing a strong interest as high-performance materials in the construction industry Resins using recycled PET offer the possibility of a lower source cost of materials for making useful polymer concrete products. Also the recycling of PET in polymer concrete would help solve some of the solid waste problems Posed by plastics and save energy. An objective of this paper is to estimate the damage of sulfuric acid, through investigating recycled PET polymer concrete, immersed at sulfuric acid solution for 84 days. As a result of testing, recycled PET PC, used $CaCO_3$ as filler, makes a problem of appearance and strength if they are exposed for long term at corrosion environment. On the other hand, recycled PET PC, used fly-ash as filler, had less effect on decrease in weight and strength. Recycled PET PC is excellent chemical resistance, resulting in the role of unsaturated polyester resin which consists of polymer chain structure accomplishes bond of aggregates and filler strongly. Also, recycled PET PC, used fly-ash as filler, is stronger resistance of sulfuric acid corrosion than $CaCO_3$, because it is composed of $SiO_2$ and very strong glassy crystal structure. Therefore, recycled PET PC, used fly-ash as filler, is available under corrosion circumstances like sewer pipe or waste disposal plant.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.903-915
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• 2011

Recently, anaerobic methane production of agricultural waste biomass has received increasing attention. Until now domestic BMP (Biochemical methane potential) studies concerned with agricultural waste biomass have concentrated on the several waste biomass such as livestock manure, food waste, and sewage sludge from WWTP (Waste water treatment plant). Especially, the lack of standardization study of BMP assay method has caused the confused comprehension and interpretation in the comparison of BMP results from various researchers. Germany and USA had established the standard methods, VDI 4630 and ASTM E2170-01, for the analysis of BMP and anaerobic organic degradation, respectively. In this review, BMP was defined in the aspect of organic material represented as COD (Chemical oxygen demand) and VS (Volatile solid), and the influence of several parameters on the methane potential of the feedstock was presented. In the investigation of domestic BMP case studies, BMP results of 18 biomass species generating from agriculture and agro-industry were presented. And BMP results of crop species reported from foreign case studies were presented according to the classification system of crops such as food crop, vegetables, oil seed and specialty crop, orchards, and fodder and energy crop. This review emphasizes the urgent need for characterizing the innumerable kind of biomass by their capability on methane production.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.2
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• pp.107-115
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• 2019

The many countries are facing the shortage of natural resources, and the supply of aggregates are being exhausted. To consider this situation a variety of studies were performed for the development of alternative resources. In particular, high density filler material was used for shielding radioactive waste, large amount of natural aggregates are required in order to produce filler material. Also, in order to improve the shielding performance of filler material, it is required to increase the density of the filler material. Therefore, in this study was carried out to provide basic data for expanding the feasibility of high density industrial waste resource as aggregate in heavyweight concrete. From the test results, OPC case, concrete strength decreased by using heavyweight waste glass as fine aggregate, however, it is improved by using mineral admixture as binder. Therefore, when the heavyweight waste glass and steel slag are applied to heavyweight concrete, it is desirable to use mineral admixture, especially to use BFS than FA. Meanwhile, when the steel slag was replaced as coarse aggregate of heavyweight concrete, elasticity of modulus and radiation shielding performance can be improved owing to high density of steel slag.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.523-531
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• 2018

The purpose of this paper is to derive priorities and implications for the organic resource conservation policy in the livestock sector. We conducted a survey on the importance-performance of the organic waste resource reclamation of livestock sector using a 5-point Likert scale. The importance average for the resource recycling of livestock organic waste was 3.63 and the average of performance was 3.04. As a result of the IPA on livestock manure recycling measures, it is necessary to improve feed quality, establish a local recycling system, increase demand for compost and liquid, enhance customer linkages, and develop cost reduction technologies. It requires intensive support for promoting the spread of odor reduction technologies and integrated management of biomass. It is necessary to introduce mid- and long-term measures such as the revival of feed in tariff, promote by-product feeding, establish solid fuel process management standards, create hygiene safety standards, develop eco-beads and promotion of feed conversion. It is required to strengthen support for the development of odor reduction technologies and prepare consultative organizations among related departments, develop eco-friendly solid fuel technology, and support policies for renewable energy certification.