• International Journal of Naval Architecture and Ocean Engineering
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• v.13 no.1
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• pp.493-510
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• 2021

Mineral wool is an insulation material commonly used in passive fire protection (PFP) systems on offshore installations. Insulation materials have only been considered functional materials for thermal analysis in the conventional offshore PFP system design method. Hence, the structural performance of insulation has yet to be considered in the design of PFP systems. However, the structural elements of offshore PFP systems are often designed with excessive dimensions to satisfy structural requirements under external loads such as wind, fire and explosive pressure. To verify the structural contribution of insulation material, it was considered a structural material in this study. A series of material tensile tests was undertaken with two types of mineral wool at room temperature and at elevated temperatures for fire conditions. The mechanical properties were then verified with modified methods, and a database was constructed for application in a series of nonlinear structural and thermal finite-element analyses of an offshore bulkhead-type PFP system. Numerical analyses were performed with a conventional model without insulation and with a new suggested model with insulation. These analyses showed the structural contribution of the insulation in the structural behaviour of the PFP panel. The results suggest the need to consider the structural strength of the insulation material in PFP systems during the structural design step for offshore installations.

• Journal of the Korean Wood Science and Technology
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• v.38 no.6
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• pp.480-489
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• 2010

We investigated the functional characteristics of commercial wood charcoal in Korea and their application as functional raw materials. The areas of analysis were anatomical features, elementary composition, mineral composition, caloric values, anion and far-infrared ray emission, and moisture absorption capacity. Based on the analyses as above mentioned, it is considered that charcoal can be evaluated as functional raw material. In commercial wood charcoal in Korea, there were highly varied depending on manufacturing methods as black charcoal, white charcoal and mechanical charcoal and manufactures for elementary composition, mineral composition, anion emission, far infrared ray emission. Especially, black charcoal showed lower moisture absorption capacity than white charcoal and mechanical charcoal. For charcoal as functional raw material, selective usage are needed based on the analyses of anatomical features, elementary composition, mineral composition, caloric values, anion and far-infrared ray emission, and moisture absorption capacity. Specific charcoal making methods for improving specific functionality, required as functional raw material, are necessary in further research.

• Journal of Soil and Groundwater Environment
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• v.28 no.5
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• pp.12-24
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• 2023

The Songji lagoon is brackish environment with a mixture of saline and fresh water, and the interaction of groundwater-lagoon water creates a physicochemical gradient. Although some studies have been conducted on the hydrological and geochemical characteristics of the Songji lagoon, microbial ecological studies have not yet been conducted. In this study, we investigated the effect of groundwater and surface water interaction on water quality as well as microbial community changes in the Songji Lagoon using 16S rRNA gene sequencing. Hydrochemical analyses show that samples were classified as 5 hydrochemical facies (HF) and hydrochemical facies evolution (HFE) revealed the intrusion phase was more dominant (57.9%) than the freshening phase (42.1%). Higher microbial diversity was found in freshwater in comparison to saline water samples. The microbial community at the phylum level shows the most dominance of Proteobacteria with an average of 37.3%, followed by Bacteroidota, Actinobacteria, and Patescibacteria. Heat map analyses of the top 18 genera showed that samples were clustered into 5 groups based on type, and Pseudoalteromonas could be used potential indicator for seawater intrusion.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.5
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• pp.984-989
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• 2011

Electrical insulation is one of the most important part in a high voltage apparatus. Recently, researchers are interested in the environmental friendly vegetable oil from environmental viewpoint. Accelerated aging transformer insulating material in vegetable oil was compared to that of mineral oil. Accelerated aging oil samples produced in the oven at $140^{\circ}C$ for 500, 1000, 1500, 2000hours. And Real transformer insulation oils samples of vegetable oil and mineral oil were aged by thermal cycles repeating from $30^{\circ}C$ to $120^{\circ}C$. Samples were analyzed at 42, 63, 93, 143, 190, 240, 300 cycles. The mineral and vegetable insulating oils were investigated for breakdown voltage, water content, total acid number, viscosity, volume resistivity, insulating paper and oil permittivity, and dissolved gas analyses. The breakdown voltage of the vegetable insulating oil is higher than that found for the mineral oil; the accelerated aging progress decreased the breakdown voltage. The vegetable oil had a higher water saturation than the mineral oil; the vegetable oil has the superior water characteristics and breakdown voltage. And high viscosity of vegetable oil, care has to be taken, especially when designing the cooling system for a large transformer.

• Journal of the Mineralogical Society of Korea
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• v.27 no.3
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• pp.135-147
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• 2014

This study analyzed spectroscopic methods for characterization of skarn minerals and sphalerite occurring in Dangdu ore deposit, and effectiveness of portable spectrometer in skarn mineral resources exploration is discussed. The spectroscopic analyses identified clinopyroxene, garnet, epidote, calcite, chlorite and sphalerite where spectral curves of clinopyroxene, garnet, epidote, and sphalerite show single mineral spectral characteristics and those of chlorite are in a mixed form with calcite and clinopyroxene. The assessment of spectroscopic analyses based on XRD analysis and microscopic observation reveals that clinopyroxene, garnet, epidote correspond well with more than 80% of detection, but sphalerite, chlorite, and calcite showed below 50% of detection rate. It is expected that skarn deposit exploration using a portable spectrometer is more effective in detection of clinopyroxene, garnet, and epidote whereas spectroscopic data of sphalerite, chlorite, and calcite needs to be utilized as a supplementary data. For the effective detection of chlorite and calcite, their content in the samples needs to be sufficient.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.10 no.2
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• pp.187-197
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• 2003

Purpose: This experimental study was to verify the effects of the mineral oil on skin under casts for relief of skin dryness and pruritus. Method: Participants in the study were inpatients at C university hospital in D city who had long leg casts. The mineral oil was applied to the skin under the casts in the experimental group of 18 patients and was not applied to the control group, also 18 patients. During the experimentation, the participants in the experimental group were informed about how to apply the mineral oil and 1 week later were responsible for applying the oil themselves. The oil was applied three times a day. Data collection was done from July 28, 2002 to September 28, 2002. The analyses were carried using frequencies, percentages, $x^2$-test, t-test, and repeated measures ANOVA with the SPSS WIN 10.0 program. Results: Hypothesis 1, 'The experimental group using the mineral oil application showed remarkably less dryness in the skin compared to the control group' was accepted (F=16.39, p=0.000). Hypothesis 2, 'The experimental group using the mineral, oil application showed remarkably less pruritus compared to the control group' was accepted (F=34.01, p=0.000). Conclusion: These results demonstrate that mineral oil application to skin under casts was effective in treating skin dryness and pruritus. Accordingly, it is concluded that mineral oil application to skin under casts can be an effective nurse intervention to treat skin dryness and pruritus.

• Asian-Australasian Journal of Animal Sciences
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• v.9 no.2
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• pp.139-147
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• 1996

Eight Philoppine forages were studied to obtain the following: 1) nutrient concentrations and digestibility, 2) distribution of the various minerals in fiber fractions through mineral analyses of neutral detergent fiber(NDF) and acid detergent fiber(ADF) residues, and 3) correlation coefficients among the factors affecting forage quality and mineral concentrations. These Philippine forages were paragrass [Brachiaria mutica (Forsk.) Stapf], stargrass (Cynodon plectostachyum Pilger), napiergrass (Pennisetum purpureum Schumach.) calopo (Calopogonium muconoides Desv.), centrocema (Centrocema pubescens Benth.), gliricidia [Gliricidia sepium (Jacq.) Walp.] leucaena [Leucaena leucocephala (Lam.) de Wit.] and sesbania [Sesbania grandiflora (L.) Poir]. Species differences(p<0.01) were observed on various nutrient fractions including mineral composition and digestibility. The cell wall(NDF) fraction, prepared by boiling in neutral detergent solution, contained the following proportions of the total mineral originally present (%): calcium (Ca), 0.7; phosphorus(P), 14.3; magnesium(Mg), 1.9; potassium(K), 3.7; copper(Cu), 16.4; zinc(Zn), 2.9; molybdenum(Mo), 9.3; cobalt(Co), 16.2; manganese(Mn), 5.6, and iron(Fe), 81.3. The ligno-cellulose(ADF) fraction, prepared by boiling in acid detergent solution, contained the following proportions of the total mineral originally present(%): Ca, 0.2; P, 4.4; Mg, 0.7; K, 2.8; Cu, 32.3; Zn, 1.1; Mo, 8.9; Co, 4.7; Mn, 5.4; and Fe, 36.8. Correlation coefficients among the factors affection forage quality and mineral concentrations were also observed. Evidently, 75 and 45% of the minerals in grasses and legumes was positively correlated to CP and IVDMD, respectively. Moreover, 55, 80 and 75% of the forage minerals was negatively correlated to NDF, ADF and ADL fraction, respetively, implying that most of the minerals reside in the non-structural cell components.

• Journal of Applied Biological Chemistry
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• v.59 no.3
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• pp.227-231
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• 2016

Deep sea water (DSW) is located 100 to 500 m below the sea surface. DSW is widely used in various fields, and is an important source of minerals that can be used to treat mineral deficiency. In the present study, the oral toxicity of DSW-mineral extracts was determined using single-dose and 14-day repeated dose oral toxicity tests in ICR mice. For the single-dose oral toxicity tests, mineral extracts of magnesium (Mg) and calcium (Ca) at doses of 0, 6, 270, 810, and 1,350 mg/kg, respectively, were orally administered to mice once at the beginning of the experiment, and the mice were observed for 14 days. For the 14-day repeated dose oral toxicity tests, Mg and Ca mineral extracts at doses of 0, 3, 135, 405, 675 mg/kg, respectively, were orally administered to mice daily, and the mice were observed for 14 days. Various tests were performed including visual observation; analysis of relative organ weight, food intake, and organ weight; biochemical analysis, and histopathology. The results indicated that mortality and changes in appearance were not observed among differentially administered groups of male and female ICR mice during the experimental period. Differences in body weight gain, food intake, organ weight, and histopathology parameters were not significant between the control and mineral-administered groups. Some results of the biochemical analyses were significantly different, but showed no specific tendencies. Overall, no evidence of toxicity was observed from the oral administration of DSW extracts of Ca and Mg in ICR mice.

• The Korean Journal of Quaternary Research
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• v.21 no.2
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• pp.69-73
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• 2007

Inorganic geochemical and mineralogical analyses from the trench sediments of the Hwayang wetland were carried out to verify the wet/dry conditions during 6000 - 5000 yr BP and abnormal event of 6300 yr BP of Korean west coast. Lithostratigraphy, mineralogy and major element concentrations of the sediments of the trench indicate that during 6000 - 5000 yr BP, a wet/dry conditions might be repeated at an interval of 200 years. Carbonate minerals precipitated with the decrease of water depth in the lake or wetland after about 6000 yr BP. On the other hand, the sediments coarser in mean grain size and larger in standard deviation were corresponded with periods of 6300 yr BP and 6230 yr BP. Especially, such a feature of grain size distribution of 6300 yr BP appears in other wetlands situated in the west coast, e.g., Hwangsan wetland and Cheollipo coastal wetland. During the period, the coarse sediments seem to have been delivered by a high energy like storming.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.185-190
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• 2005

In this study, a probabilistic prediction model for debris flow occurrence was developed using a logistic regression analysis. The model can be applicable to metamorphic rocks and granite area. In order to develop the prediction model, detailed field survey and laboratory soil tests were conducted both in the northern and the southern Gyeonggi province and in Sangju, Gyeongbuk province, Korea. The six landslide triggering factors were selected by a logistic regression analysis as well as several basic statistical analyses. The six factors consist of two topographic factors and four geological and geotechnical factors. The model assigns a weight value to each selected factor. The verification results reveal that the model has 86.5% of prediction accuracy. Therefore, it is possible to predict landslide occurrence in a probabilistic and quantitative manner.