• Journal of the Korean Professional Engineers Association
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• v.18 no.2
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• pp.6-15
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• 1985

A new process disregraded the H$_2$SO$_4$ treatment process heretofore in use, was developed and substituted for mineral base engine used oil of homemade SAE-30 grade H.V.I., which was used covering 4,500km, as samples, and the following results in research, was obtained. (1) A good quality of rerefinded base oil was obtained through roughly a course of developed processes of vacuum distillation process, solvent extraction process, neutralization treatment process and clay treatment process. (2) Through vacuum distillation process, the size of fine grains of insoluble colloid carbon that is, colloid carbon which was produced by burning of internal combustion engine oil and fuel, could be brought up and precipitated (3) The insoluble matters and admixtures could be easily dispersed and dissolved by mixing and extracting solvent disregarded the H$_2$SO$_4$ treatment process heretofore in use (4) waste matter heretofore called acid sludge in consequence of the process, did not appear at all. accordingly, the environmental pollution could be removed. (5) The troubles of corrosion to copper strip which was faults of the usual used oil refined products and peculiar offensive odor of the rerefined oil, could be solved through the neutralization process. (6) The yield of rerefined oil obtained through a course of processes was over 86 percent, and it is of practical use, not to speak of commercial value.

• Structural Engineering and Mechanics
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• v.58 no.1
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• pp.143-161
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• 2016

Utilization of mineral and chemical admixtures in concrete technology has led to changes in the formulation and mix design in recent decades, which has, in turn, made the concrete stronger and more durable. Lightweight concrete is an excellent solution in terms of decreasing the dead load of the structure, while self-compacting concrete eases the pouring and removes the construction problems. Combining the advantages of lightweight concrete and self-compacting concrete is a new and interesting research topic. Considering its light weight of structure and ease of placement, self-compacting lightweight concrete may be the answer to the increasing construction requirements of slender and more heavily reinforced structural elements. Twenty one laboratory experimental investigations published on the mix proportion, density and mechanical properties of lightweight self-compacting concrete from the last 12 years are analyzed in this study. The collected information is used to investigate the mix proportions including the chemical and mineral admixtures, light weight and normal weight aggregates, fillers, cement and water. Analyzed results are presented in terms of statistical expressions. It is very helpful for future research to choose the proper components with different ratios and curing conditions to attain the desired concrete grade according to the planned application.

• Journal of Animal Science and Technology
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• v.47 no.2
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• pp.283-292
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• 2005

This study was conducted to determine the effect of dietary supplements of mineral(pegmatite) powder on the growth performance and meat quality during 14 month in 24 heads of Hanwoo steers. The Hanwoo steers were randomly allotted 3 treatments(8 heads I treatment); Control(0 %), Tl(supplemented with pegmatite 2.0% and vitamin A 0.2 %), T2(supplemented with pegmatite 2.0 %). The body weights of control, Tl and T2 were 646.2 kg, 624.0 kg and 656.8 kg on 26 month respectively. The daily gain was higher in T2(0.87 kg) than the others. The concentration of vitamin A(retinol) in the blood serum in T1(61.75 $\ell$ I dl) was higher than' control(41.93$\ell$ I dl) and T2(46.10mg I dl)(P < 0.05). The concentration of total cholesterol was lowest in TI (130.17mgI di) than the others(P< 0.05). Marbling scores and meat quality grade were to significnatly higher in T2(5.50 and 3.50) than control(2.71 and 1.83) and Tl(3.00 and 2.00)(P< 0.05).

• Journal of Integrative Natural Science
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• v.4 no.1
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• pp.58-71
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• 2011

The precambrian gneisses are widely distributed in the Jangsu area. This study focuses on the metamorphic mineral assemblages and metamorphic P-T conditions of the gneiss. We have analyzed garnet, biotite and plagioclase among the gneiss through the EPMA analysis, and calculated the metamorphic temperature and pressure accordingly. The metamorphic temperature was estimated by the average of values from the garnet and biotite formulas, and the metamorphic pressure by value of the Hoisch(1990) geopressured on garnet-biotite-plagioclase. The mineral sample we examined shows garnet-biotite-plagioclase-quartz composite and garnet-plagioclase-orthoclase-quartz composite. Garnet shows almandine-pyrope solid solution in general, while porphyroblastic gneiss shows almandine-grossluar solid solution. The fact that the abundances, observed by garnet profile, are almost identical in both the central region and the outer egion indicates that the crystal was developed uniformly. There is almost negligible variance in biotite on metamorphic grade, and andesine is observed in plagioclase. The metamorphic temperature and pressure from EPMA analysis and its indications are as follows: the middle-temperature, high-pressure metamorphism ($500-650^{\circ}C$, 6.9-10 kbar) ensued in the beginning, and then was followed by the high-temperature, middle-pressure($600-740^{\circ}C$, 2.7-5.9 kbar) to ($500-540^{\circ}C$, 3.1 kbar) retrograde metamorphism.

• Journal of the Korean Geotechnical Society
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• v.16 no.1
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• pp.5-17
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• 2000

The physical and mechanical properties of the sedimentary rocks deposited in Taegu and Kyongbuk region have been measured in the laboratory and at the field. Four kinds of rocks such as the shale, the mudstone, the siltstone and the sandstone were the object of this study. In sedimentary rock joint, bedding made it impossible to extract cores for uniaxial compressive test. Some correlations between the uniaxial compressive strength and the other characteristic values such as Point load index, Schmidt hammer rebound, Brazilian strength, P-wave velocity and Absorption ratio are made. The chemical and mineral compositions are also investigated by the XRF and XRD analysis. In addition, the weathering grade of rocks are classified by the quantitative indices of Point load index, Schmidt hammer rebound and Absorption ratio.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.453-456
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• 2006

In this study, the experiment was carried out to investigate and analyze the influence of fineness of blast furnace slag powder on the properties of high strength concrete. The main experimental variables were water/binder ratio 27.5, 31.5, 35.5(%) water content $165kg/m^3$ and mineral admixtures such as blast furnace slag powder. Even in a case where the ratio of blast furnace slag powder is 70%, using a fineness of 8000 grade afforded a higher strength development than using a plain concrete, which indicates the potential of high utilization in the future. Although it has been pointed out that the concrete using blast furnace slag powder has a problem of yielding relatively low rate of strength development in the early age, it is demonstrated that this can be resolved by using a powder with fineness greater than 6000 grade. It is considered necessary that powder fineness should be upgraded for the applications such as high performance concrete to be used in high strength required areas by considering hydration heat control and early strength requirements in the future.

• Journal of Animal Science and Technology
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• v.66 no.1
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• pp.115-124
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• 2024

This study investigated the impact of clay mineral 'illite' (IL) on the growth performance, apparent total tract digestibility, and meat-carcass grade quality in growing-finishing pigs. One hundred fifty pigs were divided into two groups with fifteen pens/group and five pigs/pen, a control group that was fed with a corn-soybean meal-based diet and IL treated group were fed a meal-based diet supplemented with 0.5% IL. Compared to the control, IL supplementation increased average daily feed intake (ADFI) and reduce gain to feed ratio (G:F) in the pigs during days 43 to 70 and 99 to 126 and increased dry matter during days 42 and 126, and backfat thickness on day 98 (p<0.05). The drip loss was reduced on day 7, meat firmness tended to increase with dietary IL supplementation. In summary, dietary 0.5% IL supplementation improved ADFI, nutrient utilization of dry matter, and firmness and reduced G:F and drip loss of growing-finishing pigs.

• Journal of Food Hygiene and Safety
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• v.14 no.3
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• pp.277-281
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• 1999

Chemical composition of imported table salts from China (sun dried), Thailand (sun dried) and Australia (rock salt) were compared the mineral content and heavv metal contamination with Korean sun dried salt. Kimchies prepared by those salts were analyzed the quality by pH, acidity and sensory evaluation. Chemical compositions were as follows : moisturefrom 1.7% (Australia) to 8.7% (Korea), sodium chloride-from 86.7% (China, summer) to 97% (Australia), insoluble matter in water-from 0.02% (Australia) to 0.18 (China), and sulfate ionfrom 0.03% (Australia) to 1.65% (China, summer). Judging by Korean Standard(KS) of salt, salt from Australia and Thailand belong to 1st grade, Korean and Chinese (winter) to 2nd grade, and China (summer) were out of 3rd grade. Ca and Mg content of the salts tested were 0.022% (Australia) to 0.246 (China, winter), 0.036% (Australia) to 0.841% (China, summer) respectively and Pb was 1.23 ppm(China, summer)~0.61ppm(Korea) which is within the Korean regulation. The other heavy metals, Pb, Cd, As and Hg were not detected in all salts tested. The quality of Kimchi prepared by those salts were significantly no difference with Korean sun dried salt.

• Journal of the Mineralogical Society of Korea
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• v.23 no.1
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• pp.25-37
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• 2010

Ilmenite ore bodies are deposited within the Precambrian anorthosite body distributed in the Hadonggun and Sancheonggun district, Gyeongsangnamdo. This study tries to identify the occurrence of ilmenite ore body in titanium mine area distributed in Wheolheongri, Okjongmyon, Hadonggun and six mining concession areas (Danseong claim no. 64, 65, 74, 75, 84, 85) in Danseongmyon, Sancheonggun. Wheolheongri ilmenite ore body occurs as vein with about 10~50 m width and 100 m length and shows NNE strike and NW dipping. High grade ore with $TiO_2$ 20 wt% in this area is distributed in intercumulated anorthosite and is sheared and brecciated. Ilmenite occurring in this type is commonly associated with hornbelnde. Ilmenite ore bodies distributed in Danseonggun, Sancheongmyon are deposited in layered anorthosite. They occur as stratiform with variable width from several and several tens meters. Ilmenite which is disseminated in the matrix is sheared and elongated. This type shows generally low grade ($TiO_2$ 1.0~6.0 wt%). The ilmenite ore bodies occur as vein and stratiform, and the former shows higher grade than the latter.

• Korean Journal of Health Education and Promotion
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• v.26 no.1
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• pp.51-61
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• 2009

Objectives: The objective of this study was to identify the factors associated with the percentage of body fat and bone mineral density (BMD). Methods: 886 students of the 4, 5, 6th grade were sampled from 6 elementary schools in Daejeon city from May to June 2005. Participants completed the questionnaire on socio-demographic factors, eating habits and physical activities, and had the measurements of body composition, BMD, height and weight. T-test, one-way ANOVA and ANCOVA were used to compare body composition and BMD among groups defined by study factors. Multiple regression analysis was used to determine the factors related with percentage of fat and BMD in each sex. Results: When adjusting age, height, weight and family income, the amount of food intake and regular exercise including the days of exercise per week and the daily exercise duration were significantly associated with percentage of fat in boys, but not in girls. When adjusting the same variables, regular exercise, the days of exercise per week and the daily exercise duration were positively associated with BMD in both sexes. Conclusion: Regular exercise with one or more days per week were the common factor to decrease percentage of fat and increase BMD in school children. This showed that regular exercise program could improve the body composition of school children.