• Advances in concrete construction
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• v.2 no.3
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• pp.193-207
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• 2014

The study presented herein aims to investigate the durability related properties of rubberized concrete. Two types of waste scrap tire rubber were used as fine and coarse aggregate, respectively. The rubber was replaced with aggregate by three crumb rubber and tire chips levels of 5, 15, and 25% for the rubberized concrete productions. In order to improve the transport properties and corrosion resistance of rubberized concretes, SF was replaced with cement at 10% replacement level by weight of total binder content. The transport properties of the rubberized concretes were investigated through water absorption, gas permeability, and water permeability tests. The corrosion behavior of reinforcing bars embedded in plain and silica fume based rubberized concretes was investigated by linear polarization resistance (LPR) test. The results indicated that the utilization of SF in the rubberized concrete production enhanced the corrosion behavior and decreased corrosion current density values. Moreover, the reduction in the water and gas permeability coefficients was observed by the incorporation of SF in plain and especially rubberized concretes.

• Journal of the Korean Ceramic Society
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• v.52 no.6
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• pp.435-440
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• 2015

It is a challenge from an industrial point of view to fabricate silicon nitride substrates with high thermal conductivity and good mechanical properties for power devices from high-purity Si scrap powder by means of thick film processes such as tape casting. We characterize the residual carbon and oxygen content after the binder burnout followed by nitridation as a function of the temperature in the temperature range of $300^{\circ}C-700^{\circ}C$ and the atmosphere in a green tape sample which consists of high-purity Si powder and polymer binders such as polyvinyl butyral and dioctyl phthalate. The optimum condition of binder burnout is suggested in terms of the binder removal temperature and atmosphere. If considering nitridation, the burnout of the organic binder in air compared to that in a nitrogen atmosphere could offer an advantage when fabricating reaction-bonded $Si_3N_4$ substrates for power devices to enable low carbon and oxygen contents in green tape samples.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.4
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• pp.481-496
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• 2020

After nuclear power plants are permanently shut down and decommissioned, the remaining irradiated metal components such as stainless steel, carbon steel, and Inconel can be used as neutron absorber. This study investigates the possibility of reusing these metal components as neutron absorber materials, that is burnable poison. The absorption cross section of the irradiated metals did not lose their chemical properties and performance even if they were irradiated over 40-50 years in the NPPs. To examine the absorption capability of the waste metals, the lattice calculations of WH 17×17 fuel assembly were analyzed. From the results, Inconel-718 significantly hold-down fuel assembly excess reactivity compared to stainless steel 304 and carbon steel because Inconel-718 contains a small amount of boron nuclide. From the results, a 20wt% impurity of boron in irradiated Inconel-718 enhances the excess reactivity suppression. The application of irradiated Inconel-718 as a burnable absorber for SMR core was investigated. The irradiated Inconel-718 impurity with 20wt% of boron content can maintain and suppress the whole core reactivity. We emphasize that the irradiated metal components can be used as burnable absorber materials to control the reactivity of commercial reactor power and small modular reactors.

• Resources Recycling
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• v.22 no.1
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• pp.20-28
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• 2013

Recently, as the registration of vehicles increases, the utilization of the waste tires is emerging as environmental issues. Crumb rubber reproduced by scrap tires has been reused up to 25% in the construction field. The purpose of this paper is to investigate the mechanical properties of sulfur-rubber concrete (SRC) and to suggest the optimum mix design in terms of the compressive strength. Specimens were prepared with various mixing parameters: amount of sulfur, rubber, and micro-fillers. Two casting processes were also mentioned; dry process and wet process. The results mainly showed that the compressive strength of SRC decreased with an increment of rubber content. However, adding micro-filler and adjusting sulfur contents could improve the compressive strength of SRC. Optimum values of sulfur and rubber content were selected by workability and compressive strength of SRC. SRC can be applied to road constructions where high strength of concrete is not concerned, to wall panels that require low unit weight, to construction of median in highways to resist high impact load, and in sound barriers to absorb sound waves.

• Journal of Aquaculture
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• v.5 no.2
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• pp.127-142
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• 1992

A feeding experiment was carried out to investigate the availability and feasibility of fish processing by-products as a substitute for frozen round fish in moist pellet diets for flounder, Paralichthys olivaceus. A control diet was prepared by incorporating $50{\%}$ frozen horse mackerel and $50{\%}$ commercial binder feed. In test diets the frozen horse mackerel of the control diet was replaced with either tuna scrap, tuna viscera, flatfish offal, deskinned hagfish, or tuna viscera ($20{\%}$) with frozen horse mackerel ($30{\%}$). Eighty flounders, 13.4 g in mean body weight, were stocked in 12 aquaria ($250\;{\ell}$ each) and fed six experimental diets for the first 28-day experiment. For the second 23-day experiment, forty flounders,44.8 g in mean body weight, were stocked and fed the same experimental diets. All treatments were duplicated. There were no significant differences in growth, feed efficiency and nutrient utilization among fish fed experimental diets containing either frozen horse mackerel, deskinned hagfigh, flatfish offal or tuna viscera with frozen horse mackerel. However, the feeding performances of fish fed experimental diets containing tuna scrap or tuna viscera were significantly lower than those of the control diet (P<0.05). There were no significant differences among the treatments on the proximate analysis values of the whole body. However, the crude lipid content of liver of the fish fed the experimental diet containing tuna scrap was significantly lower than that of the others. The results indicate that deskinned hagfish, and flatfish offal could be successfully substituted for frozen fish portion of moist pellet diets for flounder, but tuna viscera could only be partially substituted.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.1
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• pp.182-188
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• 2008

The compounds of recycled polyethylene(PE) and fly-ashes were prepared. Polymers used were sorted PE from mixed plastics of household waste and Low Density Polyethylene(LDPE) and Linear Low Density Polyethylene(LLDPE) recycled from the scrap of packaging film plants. Fly-ashes were from the power plant and from the household waste incinerator. The tensile strength of recycled LDPE and LLDPE compounds decreased and the flexural modulus increased with greater amount of the power plant fly-ash. Anthracite fly-ash gave rise to slightly higher tensile and flexural strength of the LLDPE mixtures than bituminous coal fly-ash presumably due to higher content of unburned carbon. The incinerator fly-ash introduced to household waste PE enhanced both tensile strength and flexural modulus of the compounds. When LDPE and household waste PE were used together, the synergistic effect of incinerator fly-ash to household waste PE was offset by reduced crystallization of LDPE due to the filler particle. The compounds of household waste PE and incinerator fly-ash might be applied to structural materials for such as sewage pipe, which reduces the waste treatment cost and conserve the environment and resources.

• International Journal of Highway Engineering
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• v.18 no.4
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• pp.29-35
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• 2016

PURPOSES : The new waste management policy of South Korea encourages the recycling of waste materials. One material being recycled currently is tire-derived fuel (TDF) ash. TDF is composed of shredded scrap tires and is used as fuel in power plants and industrials plants, resulting in TDF ash, which has a chemical composition similar to that of the fly ash produced from coal. The purpose of this study was to evaluate the properties of an asphalt concrete mix that used TDF ash as the mineral filler. METHODS : The properties of the asphalt concrete were evaluated for different mineral filler types and contents using various measurement techniques. The fundamental physical properties of the asphalt concrete specimens such as their gradation and antistripping characteristics were measured in accordance with the KS F 3501 standard. The Marshall stability test was performed to measure the maximum load that could be supported by the specimens. The wheel tracking test was used to evaluate the rutting resistance. To investigate the moisture susceptibility of the specimens, dynamic immersion and tensile strength ratio (TSR) measurements were performed. RESULTS : The test results showed that the asphalt concrete containing TDF ash satisfied all the criteria listed in the Guide for Production and Construction of Asphalt Mixtures (Ministry of Land, Infrastructure and Transport, South Korea). In addition, TDF ash exhibited better performance than that of portland cement. The Marshall stability of the asphalt concrete with TDF ash was higher than 7500 N. Further, its dynamic stability was also higher than that listed in the guide. The results of the dynamic water immersion and the TSR showed that TDF ash shows better moisture resistance than does portland cement. CONCLUSIONS : TDF ash can be effectively recycled by being used as a mineral filler in asphalt, as it exhibits desirable physical properties. The optimal TDF ash content in asphalt concrete based on this study was determined to be 5%. In future works, the research team will compare the characteristics of asphalt concrete as function of the mineral filler types.

• Resources Recycling
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• v.11 no.4
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• pp.11-16
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• 2002

Analysis and separation of constituent materials of old car have been performed by using the industrial shredding line. For this aim, three old cars made by domestic automobile manufacturers, Sonata II, Sephia and Prince were chosen and delivered in pressed form without engine, tires and doors, etc. Shredding line was substantially composed of pre- and main-shredder. cyclone, magnetic separation, eddy current separation and man-power separation. From the separation of shredder products, iron scrap was observed to be the major material of old car accounting for 60.1 ％ of total weight and non-ferrous metals involving Al, Cu and Zn, etc. were about 2％. Light fluff, about 90％ of total fluff product, was comprised with plastic, fiber and sponge, etc. and the fraction of 5 cm undersize in light fluff was 70.5%. In case of heavy fluff, however. rubber and plastic were found to be the major constituent materials of it. Among the constituent materials of fluff, plastic showed the highest calorific value, more than 10,000 cal/gr and leather and rubber showed relatively high chlorine content, 10.3 and 2.55 wt%, respectively.

• Human Ecology Research
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• v.57 no.2
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• pp.225-241
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• 2019

This study develops and validates an objective scale to measure newspaper use at home by elementary school students and parents. We developed a preliminary scale of 59 items through the review of literature on newspaper use and mediation as well as the examination of content validity by education experts. Collected data were analyzed using SPSS 21.0 and AMOS 21.0 programs. A total of 42 items were supported by 703 parents with students in grades 1-6 using exploratory factor analysis. The model included 3 categories and 9 sub-factors: instruction (modeling, restriction, and text instruction), activities (play activity, conversation, online mediation, and scrap activity), and belief (academic achievement and information acquisition). Confirmatory factor analysis confirmed and validated the model fit; in addition, convergent validity, and discriminant validity, and cross validity was confirmed through correlation analysis by gender comparison and grade comparison. We also verified the validity of this scale through correlation analysis based on Yu and Jung (2012)'s newspaper mediation variables and scale in regards to children's motivation for using newspapers. Finally, internal consistency reliability and half reliability were also confirmed. In conclusion, the suitability and stability of home newspaper utilization scale for elementary students (HNUS-E) were confirmed. This scale provides parents and educators with ideas for the development of the children's literacy, cognitive, and affective domains that can be effectively used in research on newspaper use for school-aged children.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.6
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• pp.640-646
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• 2018

To determine whether there are differences in the food component characteristics of the cultured recessive small-sized abalone Haliotis discus hannai (SA; 30-40 each/kg) and middle-sized abalone (MA; 10-15 each/kg), the proximate compositions, fatty acid and total amino acid compositions of these two species were evaluated. Additionally, extraction methods were performed on the SA to asses the quality characteristics of the resulting. In terms of proximate composition, MA had lower moisture and carbohydrate levels and higher crude protein contents than SA. The total amino acid contents of MA and SA were 15,734.4 and 11,379.1 mg/100 g, respectively, the major amino acids were glutamic acid, aspartic acid, serine, glycine, alanine, leucine, arginine and lysine, and the major fatty acids were 16:0, 18:0, 18:1n-9, 18:1n-7, 20:4n-6, 20:5n-3, and 22:5n-3. The pH levels and total nitrogen and amino nitrogen contents of the hot-water extract (WE) and scrap enzyme hydrolysate (SE) samples from the SA were 6.32 and 6.05, 1.36% and 1.52%, and 342.1 and 403.1 mg/100 g, respectively. The extraction yields and free amino acid contents from SA were 1,317 and 440 mL/kg, and 8,721.1 and 9,070.7 mg/100 g, respectively, and the concentrations of major components were as follows: arginine, glycine, glutamic acid, alanine and lysine. Additionally, the complex extract (WE+SE) was superior to the traditional extract (WE) in terms of extraction yield, amino-nitrogen content, and organoleptic qualities but not odor.