• Corrosion Science and Technology
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• v.9 no.5
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• pp.216-222
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• 2010

Most of the thirteen substations in operation in the metropolitan area were installed around the year 2000, and since water cooling methods are used to directly withdraw heat from transformer oils, a stable supply of electric power is required through optimal maintenance of facilities. The water cooling tower installed outdoors, which uses the water supply as sprinkler water, experiences the most problems. Since more than 90% of the cooling water is reused, the dissolved composition in the water becomes concentrated due to long operating hours, and impurities dissolve in the water due to air flowing in from the outside, forming hard scales on the outer surface of the cooling tube, and in extreme cases, reacting with the tube material composition, leading to corrosion. As a result, not only is cooling efficiency lowered, but in extreme cases the cooling tube must be replaced. In this study, the characteristics and composition of the scales formed on the cooling tube were analyzed and corrosion characteristics of material types were identified in order to find an efficient maintenance method for cooling tubes. In addition, the degree of dissolution of various chemicals were investigated during the removal of scales that have been formed.

• Wind and Structures
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• v.14 no.1
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• pp.15-34
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• 2011

Three wind-tunnel simulations of the atmospheric boundary layer (ABL) flow in suburban country exposure were generated for length scale factors 1:400, 1:250 and 1:220 to investigate scale effects in wind-tunnel simulations of the suburban ABL, to address recommended wind characteristics for suburban exposures reported in international standards, and to test redesigned experimental hardware. Investigated parameters are mean velocity, turbulence intensity, turbulent Reynolds shear stress, integral length scale of turbulence and power spectral density of velocity fluctuations. Experimental results indicate it is possible to reproduce suburban natural winds in the wind tunnel at different length scales without significant influence of the simulation length scale on airflow characteristics. However, in the wind tunnel it was not possible to reproduce two characteristic phenomena observed in full-scale: dependence of integral length scales on reference wind velocity and a linear increase in integral length scales with height. Furthermore, in international standards there is a considerable scatter of recommended values for suburban wind characteristics. In particular, recommended integral length scales in ESDU 85020 (1985) are significantly larger than in other international standards. Truncated vortex generators applied in this study proved to be successful in part-depth suburban ABL wind-tunnel simulation that yield a novel methodology in studies on wind effects on structures and air pollution dispersion.

• Journal of Fisheries and Marine Sciences Education
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• v.21 no.3
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• pp.409-419
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• 2009

The purpose of this study was the examination of delinquency according to, narcissism, self-esteem, hostility and alienation of juvenile. For this, setting 172 students of an academic high school and 366 students of a vocational school(total 538) as the object of this study, the measures of Narcissistic Personality Scales, Self-Esteem Scales, Alienation Scales, and Delinquency Scales were inquired. The method of statistical analysis about these materials was composed of Two-way Analysis of Variance, One-way Analysis of Variance, and Multi-regression Analysis by using SPSS 10.0. The result, when delinquency was examined according to narcissism and self-esteem, in the case that narcissism was highest, self-esteem was lowest, delinquency was highest. When delinquency was examined according to narcissism and hostility, in the case that narcissism was highest, hostility was highest, delinquency was highest. When delinquency was examined according to narcissism and alienation, in the case that narcissism was highest, alienation was highest, delinquency was highest. And, when Multi-regression Analysis about the effect of narcissism, self-esteem, hostility and alienation on delinquency was administrated, the variation that affected delinquency significantly was narcissism, hostility and alienation. That is, we could look forward that the more narcissists feel hostility and alienation, the higher they have delinquency.

• Journal of the Korean Society of Clothing and Textiles
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• v.34 no.6
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• pp.913-927
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• 2010

This study investigates the influence of Likert scale formats such as the number of response categories and the inclusion of a mid-point from a methodological point of view using instruments that measure a fashionmarketing-related subject. Using a self-administered questionnaire, 201 respondents rated their economic clothing shopping orientation on three formats of scales that differed only in the number of response categories (ranging from 5 to 7) from February 8 to February 12, 2010. Descriptive statistics, Spearman's rank order correlation, t-test, exploratory factor analysis, confirmatory factor analysis, Pearson's correlation, and Cronbach's alpha were used in the analysis. The results are as follows. First, three scale formats were generally suitable for use due to validity and reliability. Second, the response results varied with the number of categories and the inclusion of a mid-point, although the differences were statistically insignificant (with only a few cases that differed). Third, construct validity was more secure in scales with fewer categories, whereas convergent and discriminant validity was generally good in all scale formats. Fourth, reliability coefficients were higher in scales with more categories. Fifth, the number of categories was of greater importance to instrument design than the inclusion of a mid-point. Implications for appropriate scale designs are suggested in this study.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.7
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• pp.101-106
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• 2004

Measurements of linear motion accuracy for one axis of NC lathe have achieved with laser interferometer system, but measurement of plane motion accuracy for two axes on zx-plane of NC lathe have not achieved with the above system. Therefore in this study, measuring unit system is organized using two optical linear scales in order to acquire error. data during of plane motion of ATC(Automatic Tool Change.) of NC lathe by reading zx-plane coordinates. Two optical linear scales of measuring unit are fixed on zx-plane of NC lathe, and moving part of the scales are fixed to the ATC and then error motion data of z, x-coordinates of the ATC are received from the scales through the PC counter card inserted in computer at constant time intervals using tick pulses coming out from computer. And then, error motion data files acquired from measuring are saved in computer memory and the aspect of plane motion are modeled to plots, and range of the error data, means. average deviations, and standard deviations etc. are calculated by means of statistical treatments using computer programs.

• Journal of the Korean institute of surface engineering
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• v.32 no.1
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• pp.49-60
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• 1999

The protective oxide scales and coatings formed on high temperature materials must be preserved in high temperature atmosphere. And the thermal stresses induced by thermal cycling and the growth stresses by the formation of oxide scales can cause the loss of adherence and spalling of the oxide scales and coated layers. Among the coating processes Al diffusion coating is favored due to thermochemical stability and superior adherence in an hostile atmosphere. In this study, protective oxide forming element, Al was coated on Ni, Inconel 600 and 690 by diffusion coating process varying coating temperature and time. And the surface stability and adherence of oxide scales formed on those Al diffusion coated materials were evaluated by thermal cycling test. Al diffusion coated specimens showed superior cyclic oxidation resistance compared to bare ones and specimens coated for longer period had better cyclic oxidation resistance, due to the abundant amount of Al in the coated layer. Meanwhile Al diffusion coated Inconel 600 and 690 showed improved cyclic oxidation resistance by the effect of Al in the coated layer and Cr in the substrate. Comparing both Al diffusion coated Inconel 600 and 690, Al diffusion coated Inconel 690 maintained better adhesion between coated layer and substrate by virtue of the bridging effect resulting from the segregation of Cr in the interdiffusion zone.

• Child Health Nursing Research
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• v.25 no.1
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• pp.56-64
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• 2019

Purpose: This study was conducted to obtain data for the development of an effective fall risk assessment tool for pediatric inpatients through a systematic review and meta-analysis of the diagnostic test accuracy of existing scales. Methods: A literature search using Medline, Science Direct, CINAHL, EMBASE, and the Cochrane Library was performed between March 1 and 31, 2018. Of 890 identified papers, 10 were selected for review. Nine were used in the meta-analysis. Stata version 14.0 was used to create forest plots of sensitivity and specificity. A summary receiver operating characteristic curve was used to compare all diagnostic test accuracies. Results: Four studies used the Humpty Dumpty Falls Scale. The most common items included the patient's diagnoses, use of sedative medications, and mobility. The pooled sensitivity and specificity of the nine studies were .79 and .36, respectively. Conclusion: Considering the low specificity of the pediatric fall risk assessment scales currently available, there is a need to subdivide scoring categories and to minimize items that are evaluated using nurses' subjective judgment alone. Fall risk assessment scales should be incorporated into the electronic medical record system and an automated scoring system should be developed.

• Safety and Health at Work
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• v.12 no.2
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• pp.192-200
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• 2021

Background: A number of accidents have occurred in small and medium enterprises (SMEs). Efforts in reducing accidents have been undertaken through the implementation of safety behaviors. Unfortunately, few studies have examined motives behind unsafe behaviors, such as safety silence motives. This study aimed to observe the motives underlying safety behaviors, namely safety silence motive (SSM) (SSM-relation, SSM-climate, SSM-issue, and SSM-job) and to evaluate the effect of SSM and safety communication on safety participation in different industrial sectors and scales. Materials and Methods: Eighty workers from two industrial sectors and scales of SMEs were involved. They were instructed to fill out a set of questionnaires. A five-Likert scale was used to respond. An independent t test was applied to find any significant differences. The partial least square-structural equation modeling for multigroup was used to develop a model on relations among the variables. Results: The results showed that SSM scores were high in SMEs, and the scores were different across industrial sectors and scales. SSM had a negative influence on safety communication, and safety communication positively influenced safety participation. Conclusion: The study of SSM, safety communication, and safety participation in different sectors and scales should be separated in SMEs.

• Journal of Conservation Science
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• v.38 no.1
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• pp.33-44
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• 2022

The study, iron-making process was examined through the scientific analysis of six by-products that were obtained during iron making at the Songdu-ri site in Jincheon. The total Fe content of the slags excavated from the Songdu-ri site was 36.29-54.61 wt%, whereas the deoxidation agent was 26.48-49.08 wt%. The compound analysis result indicated that fayalite and wüstite are the main compounds in slag. Furthermore, the microstructure analysis result confirmed the presence of fayalite and wüstite in the slag. It can be inferred from the flat shape in a bright matrix structure of the hammer scales that forging was performed in the latter stage. The Raman micro-spectroscopy results confirmed that the surface was hematite (Fe₂O₄), middle layer was magnetite (Fe₃O₄), and inner layer was wüstite (FeO). The presence of smelting and smithing slags, spheroid hammer scales, and flake hammer scales suggests that at the Songdu-ri site, iron-making process is carried out by division of labor into producing iron bloom through direct smelting, refining and forge welding, and ingot production.

• ALGAE
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• v.37 no.1
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• pp.63-74
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• 2022

Perennial stipitate kelps are globally distributed and individual species can inhabit broad latitudinal ranges, expressing notably longevous persistence. Despite the foundational role kelps provide to their communities, little is known about the variability in persistence of the stipitate kelps at local spatial scales. We studied the population persistence of Eisenia arborea, a heat- and wave force-tolerant perennial stipitate kelp with a distributional range extending from British Columbia to south of the range limit of all other northeast Pacific kelps, in Baja California Sur, Mexico. Persistence characteristics for E. arborea among sites were compared and used to test the hypothesis that stand persistence varied at local spatial scales around Isla Natividad, a Pacific island off the Baja California peninsula with documented spatiotemporal environmental heterogeneity. Collected individuals around the island were "aged" using the previously validated age estimation technique of counting annual cortical dark rings. After detecting no significant differences among sites in the covariation between estimated ages for collected individuals and stipe length, we utilized in-situ population-level stipe length measurements to more rapidly predict age structures within six stands around the island. Predicted age structures, and associated stand densities, revealed persistence characteristics and density varied at local scales and a strong positive relationship existed between stand density and stand mean and maximum ages. We speculate that stands responded differently to deterministic influences (e.g., the 2014-2016 marine heatwave and / or competition with Macrocystis) resulting in heterogenous local persistence of this foundation species.