• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.3C
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• pp.159-165
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• 2010

The problems such as natural resource exhaustion, pollutant emission and waste generation are increasing worldwide with the industrial development. The quantity of the industrial by-product in Korea is 6 million tons a year, and even its basic treatment processes including landfill, incineration and storage have reached their limits. In this study, fly ash and silica fume were applied to shotcrete to develop a method for the reuse of resources and to increase the use of fly ash, which is an industrial waste. An environmental hazard evaluation is a must to actively address the worldwide environmental problems, though. Therefore, an environmental impact assessment was conducted using the chemical content analysis test and heavy metal exudation test, for ten mixtures that were obtained through the pre-mixing and compressive strength tests. The results of the compressive strength test showed that all mixtures satisfied national and international standards. Cr, Cd and Hg were not detected, and Pb was detected only in some cases with fly ash. Cu and As were detected in all mixtures, but all of them satisfied national and international standards.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.1
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• pp.72-79
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• 2011

This study is performed to analyze the effects of CASB by applying the superplasticizer combined CASB on the ultra high strength mortar and concrete that uses different mineral admixture depending on whether the silica fume was used and the results are summarized below. From the characteristics of Fresh mortar and concrete, the fluidity was lower in B2-CASB than B2-PC from the mixing of CASB and based on the viscosity of the mortar and concrete in the binary proportion but in the ternary proportion, B3-CASB showed a larger fluidity than B3-PC because of a reduction in the restriction level due to the effects of an improvement of particle size distribution. The compression strength was higher in ternary proportion than in binary proportion and higher in CASB than in PC from the characteristics of hardening mortar and concrete and this is analyzed as a result of increased minuteness from the calcium silicate hydrates produced from the pozzolan reaction of a mineral admixture, SF, and also the charging effects of capillary pore of CASB. Overall, when using the nanomaterial, CASB in combination with a superplasticizer, the fluidity and the strength aspects of the ternary proportion of ultra high strength mortar and concrete with silica fume may be improved to a higher quality.

• Clean Technology
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• v.19 no.2
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• pp.90-94
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• 2013

We investigated one-dimensional thermal conduction for gypsum objects incorporating oyster shell powder. We presumed that according to the portion of oyster shell in the hybrid structure conductive characteristics of that would also change as some physicochemical properties such as volatile organic compound (VOC) adsorption were found to be changed considerably. Based on Fourier's 2nd law of heat conduction an analytical analysis in a flat slab (one axis perpendicular to an infinite plane) was performed. We found that composition of oyster shell and conduction-related coefficients and parameters could greatly influence on the thermal profile of that conduction, and some model experiments also served for it in the affirmative.

• KOREAN POULTRY JOURNAL
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• s.18
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• pp.56-61
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• 1971

11종의 시판 부로일러용 배합사료의 품질을 비교하기 위하여 서울대학교 농과대학에서 사료의 일반성분 및 Ca, P의 분석은 물론 572수의 스타브로계 육욕종 병아리로 8주간 사양시험을 실시하였던 바 그 결과를 요약하면 다음과 같다. 1. 부로일러 사료의 가격은 제조하는 공장에 따라 전기의 경우 공장도 가격이 kg당 41.00에서 45.00원까지, 후기의 경우 공장도 가격이 kg당 39.00원으로부터 43.20원까지, 대리점 가격은 40.20원으로부터 47.20원까지로서 상당한 차이가 있었다. 2. 부로일러 사료의 일반 성분 및 Ca, P 함량에 있어서 제조하는 공장에 따라 상당한 차이가 있었는데 전기사료의 단백질함량은 20.38$\~$23.98$\%$, 후기의 것은 17.14$\~$21.57$\%$였으며, Ca, P함량은 앞으로 개선의 여지가 많았다. 3. 부로일러 사료의 제조공장에 따라 병아리의 성장율, 사료섭취량, 사료효율 등이 현저하게 달라졌다. 대체로 최종체중은 1.74$\~$1.91kg(평균 1.82kg)이었으며 사료효율은 2.4$\~$2.6정도였다. 4. 부로일러 사료의 품질이 다르고 또한 kg당 가격이 달랐기 때문에 조수익성에 있어서도 사료에 따라 크게 달랐다. 증체나 사료효율에 미치는 영향이 비슷한 경우 사료의 가격이 싼 것을 선택하는 것이 경제적으로 유리하다는 것이 밝혀졌다. 5. 앞으로 이와 같은 유형의 시험이 주기적으로 이루어져야 사료의 품질개선을 통한 양계업자의 권익보호가 될 것으로 생각되므로 정부는 현행 사료검사제도에 생물학적 검사를 겸행하기를 건의하는 바이다.

• Journal of the Korean Society of Food Science and Nutrition
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• v.12 no.3
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• pp.273-283
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• 1983

In order to investigate the effect of the combined dietary animal and vegetable proteins on growing female and male rats and mice. 25 female and 25 male rats of 4 weeks old weighing approximately 43-65g and 47-60g, respectively, were subjected to feeding trials for 4 weeks and then subsequently to metabolic trials for 10 days. In case of mice, 25 female and 25 male mice of 4 weeks old weighing approximately 12-17g and 12-16g, respectively, were equally treated. The dietary energy level was set as 3600 kcal ME/kg, and protein and fat provided respectively 12 and 5% of the dietary energy. The rest 83% of the energy level was supplied with appropriate amounts of starch and glucose. The following results were obtained. The body weight gain of female and male rats were increased as the combined dietary animal protein level increased. Whereas that of male mice was the highest for the diet E(Ap 10+Vp 90). Food efficiencies both of female and male rats were improved as combined dietary of animal protein increased. Male rats were superior to that of female. In the mice, the food efficiency value of male mice was superior to that of female. And the values of the male showed the same fashion as that in the growth rate, although it was not for the female. Protein efficiencies, both of female and male rats, were improved as combined dietary of animal protein level increased. That of male mice was in accord with the body weight gain and food efficiencies. But that of female mice was not accordant. Nitrogen retention of the experimental diets in the same protein level was in proportion to nitrogen intake. That of male mice was improved as animal protein level increased, but, that of female mice was not. Body protein utilizability was found to be superior in mice to rats. Blood serum protein level was not found to be affected by the experimental diets in the same protein level. The best combination ratio of animal and vegetable protein seems to be variable depending on the sex and species of animals, and the best diets for female and male rats and female and male mice were found to be experimental diet A(Ap 10+Vp 90) or diet B(Ap 75+Vp 25), diet C(Ap 50+Vp 50), and diet E(Ap 10+Vp 90), respectively. From the above-mentioned results that there was no difference in growth rate of body weight gain from the weanling period to puberty, and that the protein requirements of rats and mice were different from each other.

• Journal of Aquaculture
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• v.17 no.2
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• pp.144-150
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• 2004

This experiment was conducted to evaluate the parameters such as nutrient requirements, POY, AnV, Totox, VBN, total plate count, dietary fatty acids and amino acids composition, that are not included in the registered standard composition items required by the Ministry of Agriculture and Forestry, of a moist pellet (MP), three domestic extruded pellets (DEP-1, DEP-2, DEP-3), and two foreign extruded pellets (FEP-1, FEP-2) that are utilized by domestic flounder farms at present. The crude protein was added in excess of the dietary protein requirement in 6 kinds of feeds. When considering the proper PH ratio, it is obvious that protein was added in excess, especially in MP and FEP-2. Crude fat was also added in excess, especially in FEP-1. MP contained a higher dietary phosphorus content than formulated feeds, surpassing the dietary phosphorus requirement and greatly increasing the possibility for causing water pollution. The oxidation of fatty acid and decomposition of protein in MP were higher than in formulated feeds, and may also cause problems on fish farms. Also, it is difficult to store and manage MP, Among the fatty acids, EPA and DHA contents in MP were higher than those in formulated feeds. It is necessary to conduct further studies of EPA and DHA contents in formulated feeds. Lysine content in MP and FEP-2 could meet the dietary lysine requirement of flounder, however, the possibility of insufficient lysine content in the other formulated feeds was high and we considered that extra supplementation was necessary. Therefore, it is necessary to set up quality control standards according to fish species and sizes while considering the specific character of aquatic formulated feeds to restore the confidence of feed companies and aquaculturists to these feeds. This may be an opportunity to make an earlier change from MP to formulated feeds.

• Journal of the Korea Institute of Building Construction
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• v.22 no.4
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• pp.337-345
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• 2022

The foundation of high-rise concrete building in coastal areas generally must be installed in an integrated manner, not separately, in order to prevent defects caused by stress on the upper and lower parts of the mounting surface and to manage the process smoothly. However, when performing integrated punching, there is a concern that temperature stress cracks may occur due to hydration heat. Due to the large member size, it is difficult to make a sufficient commitment, so it is necessary to mix concrete with high self-charging properties to ensure workability. In this research, the amount of high-performance spray and admixture used was adjusted as experimental variables to satisfy this required performance. Through the analysis of the results for each blending variable, it was found that the unit quantity was 155kg/m³ and the cement ratio in the binder was 18%, and the target values of the pre-concrete properties and compressive strength were satisfied. A four-component binder(18% cement, 50% slag fine powder, 27% fly ash, 5% silica fume) was used.

• Journal of Aquaculture
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• v.20 no.1
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• pp.51-55
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• 2007

This study was conducted to evaluate the muscle quality of the olive flounder fed on extruded pellet (EP) diets compared with a raw fish moist pellet (MP) diet for olive flounder, Paralichthys olivaceus in a commercial scale for a year. The sensory and physical qualities and palatable compounds were compared for evaluation of muscle quality in fish. Four diets were formulated for this experiment: two experimental EP diets (EP 1 and 2), one commercial EP diet (CEP) and MP diet. Crude lipid of fish fed EP1 and EP2 was significantly higher (P<0.05) than that of fish fed CEP, but not significantly different from that of fish fed MP (P>0.05). In the palatable compounds, the free amino acids composition were much alike in that of all the diets. Proline, glycine and alanine from fish fed diet EPs were the most abundant compound among amino acid compositions. There was little difference in the free amino acid compositions of all flounder from localities and the growing conditions between wild and cultured fishes. Taurine of fish fed EP1 was dominantly high over that of fish fed EP2, CEP and MP. In all nucleotides and their related compounds, ATP and IMP from fish fed EP diets were higher (P<0.05) than those of fish fed MP. In the sensory score, overall-acceptability of fish fed EP2 were significantly higher (P<0.05) than that of fish fed EP1, CEP and MP. Hardness of physical properties from fish fed EP2 was significantly higher (P<0.05) than those of fish fed CEP (P<0.01). These results strongly suggest that diets EP could be developed to replace MP diet for the grow-out stage of olive flounder without adverse effect on growth performance.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.4
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• pp.475-481
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• 2022

Recycled aggregates show high water absorption rate compared to natural aggregates due to microcrack developed during production process and adhered cement pastes at the surface of recycled aggregates. This leads to the deterioration of mechanical properties and slow work flow. Currently it is getting hard to satisfy high demand for natural aggregates. Utilizing recycled aggregate more widely may be a substitutable countermeasure for the shortage of natural resources. In this study, two-stage mixing approach(TSMA) suggested by Tam et al. is used to produce recycled aggregate concrete(RAC) with 100 % replacement of coarse natural aggregate and tests for compressive strength, elastic modulus, and chloride ion diffusion coefficient are conducted to find out the effect of TSMA compared to normal mixing method. According to experimental result compressive strength and elastic modulus of RAC with TSMA was superior to those of RAC with normal mixing irrespective of water-cement ratio, and in some cases mechanical properties of RAC with TSMA approached to those of natural aggregate concrete(NAC). However, chloride ion diffusion coefficient of RAC was higher than that of NAC. This illustrates that TSMA is not an appropriate method in reducing chloride ion diffusion coefficient, resulting in inconsequential contribution of TSMA to the durability of RAC.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.3
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• pp.250-258
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• 2016

Until now, the construction material industry has been recognized as a typical environmental destruction industry. However, recently, in order to reduce $CO_2$ emission, the main cause of environmental problems, lots of studies have been done about recycling industrial by-products and construction wastes. Therefore, the purpose of this study is to confirm whether it is possible to use as an alternative material in cement production process as a part of the development of recycled cement using an inorganic construction waste. For this study, the inorganic construction wastes was collected and analyzed each chemical component by XRF(X-ray Fluorescene). Also, the inorganic construction wastes were combined based on the chemical component of the cement, to perform this analysis. As a result, when the inorganic construction wastes was properly combined, it is possible to consider the development of the recycled cement used the inorganic construction wastes.