• Advances in concrete construction
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• v.5 no.6
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• pp.613-624
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• 2017

In this paper, an experimental investigation was carried out to study the effect of volume fraction of fiber and maximum aggregate size on mode-I fracture parameters of high strength concrete. Total of 108 beams were tested on loading frame with three point loading, the variables in the high strength concrete beams are aggregate size (20 mm, 16 mm and 10 mm) and volume fraction of fibers (0%, 0.5%, 1% and 1.5%). The fracture parameters like fracture energy, brittleness number and fracture process zone were analyzed by the size effect method (SEM). It was found that fracture energy (Gf) increases with increasing the Maximum aggregate size and also increasing the volume of fibers, brittleness number (${\beta}$) decreases and fracture process zone (CF) increases.

• Journal of Nutrition and Health
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• v.55 no.6
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• pp.699-708
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• 2022

Purpose: Adequate nutrition is to be provided for normal growth and development during early childhood. Currently, childcare teachers provide lunch to most children in Korea. The purpose of this study was to investigate the portion size provided by teachers and examine the effect of education on food serving size. Methods: The subjects were childcare teachers (n = 120) in charge of children aged 3-5 years at a daycare center in Hanam-si. The survey was conducted through questionnaires which included questions on the general characteristics of the teachers, their nutritional education status, and the source of nutrition information. In addition, the portion sizes of items on the menu currently provided to children were measured and the data were analyzed. To assess the effectiveness of education in determining serving size, the subjects were randomly equally divided into two groups. In the first group (n = 60) theoretical education on nutrition and serving sizes was given, whereas in the second (n = 60), practical education on these topics was provided. Results: The difference between the actual portion size of rice and the serving size announced on the menu was observed to decrease along with the increase in the experience of the teacher, although the differences in the main dish and kimchi were higher. The gap between the serving size mentioned in the menu and the portion size distributed widened as the age of the teachers increased. Notably, the difference between the portion size and the serving size of food decreased after both practical and theoretical education. Furthermore, the effect of education on the serving size of the main dishes (p < 0.001), side dishes (p < 0.01), and kimchi (p < 0.01) was observed to be greater in the practical education group than in the theoretical education group. Conclusion: Regular education should be provided to teachers on the serving sizes mentioned in the menu, as the quantity of food served depends on the experience and age of teachers. In the case of rice, theoretical education alone sufficed to ensure a proper serving size. However, hands-on training on the main and side dishes, and kimchi would be much more helpful.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.4
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• pp.483-490
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• 2010

The objectives of this study were to measure particle size and evaluate the effect of increasing alfalfa hay particle size on production characteristics in lactating Holstein dairy cows. Ninety multiparous Holstein cows in early to mid-lactation were randomly assigned in a complete randomized design for a 30-day period. Animals were offered one of the three diets, which were identical in energy, protein, and chemical composition, but differed only in particle size of alfalfa hay. The treatments were A) total mixed ration (TMR) in which only fine chopped alfalfa hay was incorporated in the ration, B) the same diet in which half of the alfalfa hay was fine chopped and incorporated in the mixed ration and half was long hay and offered as a top dressing, and C) the same diet with long hay alfalfa offered as a top dressing. Distribution of particle size of rations was determined through 20,000, 8,000 and 1,000 ${\mu}m$ sieves. The new method of quantitative determination of manure index was examined for each cow on different treatments. The geometric mean length of particle size in the rations was 5,666, 9,900 and 11,549 ${\mu}m$ for treatments A, B and C, respectively. Fat corrected milk (4%), milk fat percentage and production were significantly different (p<0.05) in treatment A versus B and C (fat corrected milk (FCM, 4%)) 28.3 vs. 35.2 and 32.3 kg/d, fat percentage 2.89, 4.04 and 3.62; but the change of ration particle size had no significant effect on milk production (p>0.05). Blood concentration of cholesterol in treatment A was significantly higher (p<0.05) than treatment B and C (181.0 vs. 150.0 and 155.2 mg/dl). Manure index in treatment C was significantly different (p<0.05) from treatment B (15.86 vs. 17.67). Based on these experimental findings, it is concluded that an increase in the ration particle size can increase milk fat percentage due to providing more physically effective fiber, which in turn could effect changes in manure consistency.

• Journal of the Korean Society of Safety
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• v.34 no.3
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• pp.28-35
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• 2019

Dry water is a core-shell structured powder which comprises a very fine water core covered with hydrophobic silica particles. Recently, the dry water has attracted attention as a new type of fire extinguishing agents. However, characteristics of the dry water as a fire extinguishing agent have not been revealed until now. To our best knowledge, this is the first work to uncover effects of particle size of the dry water on the fire extinguishing performance. Pristine dry water, which has heterogeneous particle size distribution, was carefully separated by sieving method into three fractions which were a small size (ca. $110{\mu}m$) fraction, a medium size (ca. $220{\mu}m$) fraction and a large size (ca. $400{\mu}m$) fraction. Microscopic observations confirmed the effective separation of dry water's particle size. In extinguishing tests of wood cribs fire, the medium size dry water showed most excellent fire extinguishing performance, as compared to other dry waters having small (ca. $110{\mu}m$) and large (ca. $400{\mu}m$) particle size. The good performance of the medium size (ca. $220{\mu}m$) dry water may be attributed to the balance between cooling effect of the water core and smothering effect of the silica particles. It is also revealed that small size dry water has poor flowability than large size dry water.

• Korean Journal of Child Education & Care
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• v.19 no.2
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• pp.145-163
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• 2019

Objective: The purpose of this study was to systematically arrange previous ones on developmental effects of play in early childhood through a meta-analysis. Methods: For this purpose, the researchers searched for variety of databases and analyzed 110 studies, which were 90 graduate theses and 20 journals from 2005-2016. Results: First, the total developmental effect size of infant play was 1.21, with the effect size of the experimental group being 38.7% higher than that of the control group. The total developmental effect size was .81, however when inserted effect size was calculated, so it was supposed that the current effect size might be decreased, if missing studies were included. Second, effect size appears in all developmental areas, though actual effect size of sub-factors of child development tends to be mostly decreased: The fall in physical development fell down from 1.28 to .95 that emotional development was 1.42 to .86. The fall in social development was considerable from 1.13 to .85 that cognitive development was 1.19 to 1.07. In language development, it didn't change much. It stayed about the same as 1.30. The fall In creativity development stood at just below from 1.00 to .69. Third, effect size by moderating variables was examined to show that there were statistically significant difference in measurement, age, total number of training and types of activities between two groups. Conclusion/Implications: The results of this study have an implication, in that the study verified that infant play reflects and promotes child development and functions as a tool for developmental change, by illuminating effects of it child development.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.1231-1232
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• 2011

• Journal of Powder Materials
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• v.13 no.5 s.58
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• pp.360-365
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• 2006

The phase stability of tetragonal phase in Y-TZP was investigated in terms of the distribution of grain sizes and heat-treating atmosphere. Y-TZP with various grain sizes were prepared using duration time at $1600^{\circ}C$ as experimental parameter. Accumulated grain size distributions were built from the SEM micrographs and the amount of tetragonal phase were measured using XRD. Both results were compared to determine the critical grain size before and after heat-treatment in vacuum. The critical grain size drastically decreased compared with the small increase of average grain size due to the autocatalytic effect which critically affects the tetragonal to monoclinic phase transformation. After heat-treatment in reductive atmosphere critical grain size relatively increased due to the stabilization of tetragonal phase. The formation of oxygen vacancies during heat-treatment was ascribed to the increase of stability.

• Journal of the Korean Society of Clothing and Textiles
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• v.40 no.6
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• pp.1150-1163
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• 2016

This study makes use of meta-analysis to statistically integrate the quantitative results of individual research on the influence of fashion product attributes on purchase; in addition, this study utilizes the effect sizes of correlation coefficients. This study was based on 24 individual studies from January 2000 to March 2015. The meta-analysis analyzed 91 effect sizes and 24 studies and calculated the correlation coefficient effect sizes. A random effect model was employed for meta-analysis because the results for the homogeneity test indicated that the effect sizes of each research were heterogeneous. The analysis results are as follows. First, when the total effect sizes of the fashion product attributes that influence clothing purchase decisions were calculated as .256; this indicated that the effect size is slightly below the mid-sized level. Second, upon examining the effect sizes of the categorized fashion product attributes, the intrinsic attributes yielded .222, extrinsic factors yielded .235, and the compiled attributes yielded .420; this demonstrated that the compiled attributes have a larger effect size than individual attributes. Third, when they were measured by the characteristics of study targets, they were larger for a mixed-gender group than women as well as for ordinary citizens than university students. When the effect sizes were measured based on the characteristics of fashion products as suggested in the study, there were significant differences with respect to sportswear, followed by SPA brand clothing, general clothing, fashion accessories, and designer clothing. The cases where the clothing were purchased in non-retail stores were found to have a slightly larger effect size than those of offline retail stores when the effect sizes were measured based on purchase routes; however, the difference was not statistically significant. Next, an investigation of the trend of effect sizes based on published year via the meta regression analysis indicated slightly larger effect sizes as shown in more recent publications, but this was not statistically significant.

• Journal of the Korea Society of Computer and Information
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• v.22 no.4
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• pp.115-122
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• 2017

The purpose of this study was to evaluate the effect of job satisfaction on turnover intention and organizational commitment in nurses through a systematic literature review and meta-analysis. For the study purpose, 26 studies were selected through a systematic process of using several databases and used to estimate the effect size of correlation between 3 variables. Meta-analysis was applied by usingcrandom effects model, and effect sizes on three types were calculated. Results are as follows. First, the effect size of correlation between job satisfaction and turnover intention is -.58. Second, the effect size of correlation between job satisfaction and organizational commitment is .77. Third, for the organizational commitment and turnover intention relationship, the effect of correlation is -0.68. Furthermore, publication bias analysis were assessed the results by using the funnel plot, Egger's regression test, fail-safe N, and trim-and-fill test. Based on these results, implications for the study were discussed.

• Interaction and multiscale mechanics
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• v.4 no.2
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• pp.107-122
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• 2011

Mechanical behavior in nano-sized structures differs from those in macro sized structures due to surface effect. As the ratio of surface to volume increases, surface effect is not negligible and causes size-dependent mechanical behavior. In order to identify this size effect, atomistic simulations are required; however, it has many limitations because too much computational resource and time are needed. To overcome the restrictions of the atomistic simulations and graft the well-established continuum theories, the continuum model considering surface effect, which is based on the bridging technique between atomistic and continuum simulations, is introduced. Because it reflects the size effect, it is possible to carry out a variety of analysis which is intractable in the atomistic simulations. As a part of the application examples, the homogenization method is applied to micro/nano thin films with porosity and the homogenized elastic coefficients of the nano scale thickness porous films are computed in this paper.