• Journal of the Korean Society of Safety
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• v.30 no.2
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• pp.14-20
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• 2015

The content of hazardous heavy metal of materials used in playground facility for children was investigated using X-ray fluorescence (XRF) and inductively coupled plasma (ICP) analyses, In order to examine the content of hazardous heavy metals according to the material color, four colors, i.e., green, red, yellow and blue, were categorized on the materials used. The highest lead content is observed in the yellow plastic samples. The yellow samples with relatively high lead content show that the chrome content is also high. This can explained that lead chromate, so-called chromium yellow, is normally used as a main pigment to express the yellow color. Therefore, it is concluded that hazardous heavy metal detected in the materials of playground facility for children is due to the pigments used for coloring. Based on above findings, the relationship between the color of materials used in playground facility for children and the content of hazardous heavy metal is discussed.

• Journal of Korean Elementary Science Education
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• v.29 no.4
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• pp.526-537
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• 2010

The purpose of this study was to compare the effects of two different types of texts, which were narrative and expository, on the understanding of content. Elementary students' perceptions of the two types of the texts were also investigated. In the comparison of the effects on the understanding of the text contents, test scores of mind-mapping, closed-answer question, and essay test were used. The analyses of mind-mapping tests showed narrative text was more effective to figure out main concepts of the text throughout the mind-mapping test. But expository text was more effective in the hierarchical organization of the concepts. In the closed-answer questions and essay test, narrative text was more effective than expository text. However when the contents of text were difficult and complex, there was no meaningful difference between the two types of texts. The analyses of students' perceptions of the texts showed that narrative texts were preferred. Students perceived that the narrative text was more interesting and familiar. However, the perceptions of helpful text for their science learning were not different by the types of texts.

• Journal of the Korean Ceramic Society
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• v.52 no.2
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• pp.154-158
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• 2015

This paper investigates the reaction rates of $CO_2$ that stores carbonation through comparing the carbonation behavior between $Ca(OH)_2$ and fly ash with circulating fluidized bed combustion (CFBC) containing a large amount of free CaO. Because fly ash with CFBC contains abundant free CaO, it cannot be used as a raw material for concrete admixtures; hence, its usage is limited. Thus, it has been buried until now. In order to consider its reuse, we conduct carbonation reactions and investigate its rates. X-ray diffraction (XRD), thermogravimetric/differential thermal analysis (TG/DTA), and X-ray fluorescence (XRF) are conducted for the physical and chemical analyses of the raw materials. Furthermore, we use a PH meter and thermometer to verify the carbonization rates. We set the content of the fly ash of CFBC, $Ca(OH)_2$, $CO_2$ flow rate, and water to 100 ~ 400 g, 30 ~ 120 g, 700 cc/min, and 300 ~ 1200 g, respectively, based on the content of the free CaO determined through the TG/DTA analyses. As a result, the carbonization rate of the fly ash with CFBC is the same as that of $Ca(OH)_2$, and it tends to increase linearly. Based on these results, we investigate the carbonization behavior as a function of the free CaO content contained in the raw material.

• Journal of Forest and Environmental Science
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• v.38 no.4
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• pp.263-274
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• 2022

Quarrying of rock for construction purposes is a significant industry in any economy but has its negative impact. This study examined the impact of quarry activities on surrounding vegetation in Ogun State. Geographic Information System approach was used to map the various quarry locations present in different Local Government Areas in Ogun State; of which eight sites were selected namely Isara, Idode, Iwaye, Ogbere, Ilagbe, Adelokun Baaki Ake and Igodo. Vegetation composition analyses were carried out on the eight sites using Haga Ultimeter and chlorophyll content analysis. Data were subjected to descriptive and inferential statistics using SAS package (9.4 version). Sixty quarries were identified with Odeda Local Government Area (38.3%) having the highest percentage of quarry. The vegetative compositions analyses showed that Albizia zygia had the highest frequency (7) among identified plants in the quarries. The chlorophyll content of Albizia zygia in the wet season (492.2 mg Chl/m²) was significantly higher than dry season (464.4 mg Chl/m²) in all locations. However, Baaki Ake (Albizia zygia) chlorophyll content was highest among other locations in both seasons. In conclusion Albizia zygia showed highest resistance to quarry activities, hence common among other plants identified around the quarries.

• Journal of the Korean Society of Safety
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• v.16 no.1
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• pp.53-58
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• 2001

Constructions on the soft clay layer of low strength and high compression bring out many problems. Recent studies show that strength of the soft clay layer could be substantially improved by mixing quicklime. For the purpose, a series of uniaxial compression tests were performed, using quicklime, in order to analyze strength characteristics. The major test results are summarized following : When water content is 90%, the strength is observed to precipitously increase between 3～14 days, then, the extent slowly increase in relative terms. When water content is 130%, the strength is observed to precipitously increase up to 28 days. When the strength of water content 90% is compared to that of water content 130%, the initial strength of the former is higher than that of the latter. The analyses show that the improvement of soft clay layers can be realized by the mixture of both quicklime and sand, and by the mixture of quicklime only.

• Journal of Forest and Environmental Science
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• v.29 no.3
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• pp.200-210
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• 2013

Biochemical characteristics of 24 Pongamia pinnata genotypes (candidate plus trees) from three agroclimatic zones were estimated and molecular characterization through RAPD markers was done. Various biochemical characters viz. seed oil, total carbohydrates, protein, acid value and Iodine number recorded significant variation among different genotypes. The highest seed oil content was 41.87% while seeds of 14 genotypes recorded above average (32.11%) for the trait. Seed oil and protein content exhibited a significant positive correlation and moderate heritability. Out of the initially selected twenty-five random primers, twenty-two RAPD primers were found to be highly reproducible and produced a total of 183 loci of which 147 (80.32%) loci were polymorphic. Percentage of polymorphism varied from 44% to 100% with an average of 80.62%. High level of genetic variation was found among different genotypes of P. pinnata. Both molecular and oil content (biochemical) markers appeared useful in analyzing the extent of genetic diversity in Pongamia and the result of these analyses will help to better understand the genetic diversity and relationship among populations. Overall, the Pongamia genotypes included in the study showed a correlation with their geographical origins such that genotypes from the same region tend to have higher genetic similarity as compared to those from different regions. However, in UPGMA based Nei's analysis, some genotypes were found not to be grouped based on geographical origins possibly due to the exchange of germplasm over time between farmers across the regions. The results from oil content analyses showed that several genotypes in 'Central and Western Plateau' agroclimatic zone of Jharkhand displayed a good potential for high oil content. The study provides insight about P. pinnata populations in Jharkhand (India) and constitutes a set of useful background information that can be used as a basis for future breeding strategy and improvement of the species.

• Water for future
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• v.29 no.4
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• pp.119-129
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• 1996

The daily soil water contents were obtained from the time domain reflectometry (TDR) method and energy balance-water budget approach with eddy correlation at the two small semiarid watersheds of Lucky Hills and Kendall during the summer rainy period. There was a comparison of daily soil water content measured and estimated from these two different approaches. The comparison is valuable to evaluate the accuracy of current soil water content measuring system using TDR and energy balance-water budget approach using eddy correlation method at small watersheed scale. The degree of similarity between the regressions of these two methods of measuring soil water content was explained by determining the correlations between these methods. Simple linear regression analyses showed that soil water content measured from TDR method was responsible for 58% and 63% of the variations estimated from energy balance-water budget approach with eddy correlation at Lucky Hills and Kendall, respectively. The scatter plots and the regression analyses revealed that two different approaches for soil water content measurement at small watershed scale have no significant difference.

• Earthquakes and Structures
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• v.13 no.4
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• pp.353-363
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• 2017

The present study considers a multi-span continuous bridge, isolated by lead rubber bearing (LRB). Dynamic soilstructure interaction (SSI) is modelled with the help of a simplified, sway-rocking model for different types of soil. It is well understood from the literature that SSI influences the structural responses and the isolator performance. However, the abovementioned effect of SSI also depends on the earthquake ground motion properties. It is very important to understand how the interaction between soil and structure varies with the earthquake ground motion characteristics but, as far as the knowledge of the authors go, no study has been carried out to investigate this effect. Therefore, the objectives of the present study are to investigate the influence of earthquake ground motion characteristics on: (a) the responses of a multi span bridge (isolated and non-isolated), (b) the performance of the isolator and, most importantly, (c) the soil-structure interaction. Statistical analyses are conducted by considering 14 earthquakes which are selected in such a way that they can be categorized into three frequency content groups according to their peak ground acceleration to peak ground velocity (PGA/PGV) ratio. Lumped mass model of the bridge is developed and time history analyses are carried out by solving the governing equations of motion in the state space form. The performance of the isolator is studied by comparing the responses of the bridge with those of the corresponding uncontrolled bridge (i.e., non-isolated bridge). On studying the effect of earthquake motions, it is observed that the earthquake ground motion characteristics affect the interaction between soil and structure in such a way that the responses decrease with increase in frequency content of the earthquake for all the types of soil considered. The reverse phenomenon is observed in case of the isolator performance where the control efficiencies increase with frequency content of earthquake.

• Journal of Engineering Education Research
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• v.18 no.6
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• pp.64-69
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• 2015

A video-work story analysis system based on emotional state measurement includes a content provision unit which provides story content of a video-work, a display unit which displays content provided by the content provision unit, an emotional state measurement unit which measures a tense-relaxed emotional state of a viewer viewing the displayed story content, a story pattern analysis unit which analyzes the tense-relaxed emotional state measured from the emotional state measurement unit according to a scene in the story content provided by the content provision unit, and a story pattern display unit which prints out an analysis result or displays the analysis result as an image. The emotional state measurement unit measures a tense or relaxed emotional state through one or more analyses among a brainwave analysis, a vital sign analysis, or an ocular state analysis. A writer may obtain support in an additional scenario modification work, and an investor may obtain support in making a decision through the above description. Furthermore, the video-work story analysis system and analysis method based on emotional state measurement may extract a particular pattern with respect to a change in an emotional state of a viewer, compile statistics, and analyze a correlation between a story and an emotional state.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1996.06b
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• pp.134-139
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• 1996

This paper discusses the user interface for content selection with a video-on-demand system. We suggest two modes for the selection process: active and passive. This paper analyses various video intensive user interfaces using logs of user operation to understand how users behave in each mode.