• The Journal of Korean Academy of Prosthodontics
• /
• v.32 no.3
• /
• pp.411-430
• /
• 1994

The denture may be fractured accidentally by an impact while outside the mouth, or may be cracked or broken while in service in the mouth. The latter is generally a fatigue failure caused by repeated flexure over a period of time. This investigation compared the flexural fatigue resistance, the impact force and the transverse strength of two denture base materials with and without the grid strengthener, the T300, the T800 and the Kevlar fiber to evaluate the fracture resistance. The distribution and behavior of fibers across fracture lines were examined by Hi-Scope Compact Microvision System. Through analyses of the data from this study, the following conclusions were obtained. 1. The flexural fatigue resistance, impact strength and transverse strength of high impact strength resin were higher than those of conventional heat polymerizing resin, but statistically there was no significant difference(p>0.05). 2. All specimens with and without the grid strengthener did not show significant differences in the flexural fatigue, the impact and the transverse strength test(p>0.05). 3. All specimens reinforced with the T300, the T800 and the Kevlar fiber showed significant increase of the fatigue resistance and the impact force(p<0.05). 4. All specimens reinforced with the T800 and the Kevlar fiber showed significant increase of the transverse strength(p<0.05). 5. All specimens reinforced with the T300, the T800 and the Kevlar fiber exhibited greenstick fractures. The fibers tended to remain enveloped in the resin, resisting pull-out.

• Child Studies in Asia-Pacific Contexts
• /
• v.1 no.1
• /
• pp.1-23
• /
• 2011

Many immigrant youth and their families undergo painful separations and complicated reunification experiences. Using data from the Longitudinal Immigrant Student Adaptation (LISA) study, a 5-year longitudinal, mixed-methods study of newcomer youth to the U.S., we examine the impact of lengthy family separations on youth's mental health and their perceived family conflict. Quantitative analyses demonstrate that longer separations positively predict higher psychological symptoms and family conflict, particularly for girls over a sustained period of time. Qualitative analyses of parent and child responses provide insights into the family reunification experiences.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 1998.11a
• /
• pp.151-155
• /
• 1998

The Anyang river drains a highly polluted industrial area and enters the lower part of Han river. In this preliminary study for the comprehensive understanding of geochemical behaviour of elements in the stream sediments and its implications on the river chemistry and ecology, major and trace elements in stream sediments, suspended solids and stream water were analysed to look into elemental enrichments and elemental behaviour with distance from upper part of the stream. Chemical analyses of the stream sediments show enrichements of heavy metals including Cr, Zn, Ni, Co between 10 to 100 times. Other trace elements, Cd, Pb and As are also enriched between several to 10 times, based on relative ratio with Al in fresh rock. Chemical analyses of the sediments, suspended solids and water show indications of anthroporgenic impact for the heavy metal accumulation. It was nortworth Hg is detected between 2 and 4 ppb in the water.

• Culinary science and hospitality research
• /
• v.13 no.3
• /
• pp.166-174
• /
• 2007

The purpose of this paper is to show how job satisfaction and job immersion are influenced by kitchen equipment and layouts. For verifying the credibility and availability of the results, the methods of inter-relational and factor analyses are carried out, based on 214 collected data from the questionnaire answered by employees involved in six 5-star hotel kitchens around Seoul area. Through the process of data coding and SPSS Win 12.0 program, those collected data are verified with a correlation analysis after having been carried out with frequency, factor and creditability analyses. The results are in the followings: kitchen equipment has a significant effect on job immersion as well as on job satisfaction while the kitchen layouts also give a desirable impact on job immersion and job satisfaction. In addition to them, the results show that job satisfaction also has an effect on job immersion. It is concluded that good kitchen equipment and layouts make kitchen workers turn to job immersion and satisfaction more, which will consequently have good effects on business.

• Transactions of the Korean Society of Pressure Vessels and Piping
• /
• v.15 no.2
• /
• pp.40-49
• /
• 2019

In this paper, failure probabilities of the OPR1000 reactor vessel under pressurized thermal shock (PTS) were estimated using the probabilistic fracture mechanics code, R-PIE. Input variables of initial crack distribution, crack size, copper contents, and upper shelf toughness were selected for the sensitivity analyses. A wide range of the input data were considered. Through-wall cracking frequencies determined by the product of the vessel failure probability and the corresponding occurrence frequency of the transient were also compared to the acceptance criterion. The results showed that transient history had the most significant impact on the vessel failure probability. Moreover, conservative assumptions resulted in extremely high through-wall cracking frequencies.

• Steel and Composite Structures
• /
• v.5 no.5
• /
• pp.345-358
• /
• 2005

The response of single story buildings and other case studies are investigated to observe trends in response and to develop a better understanding of the impact of some design parameters on the seismic response of CBF. While it is recognized that many parameters have an influence on the behavior of braced frames, the focus of this study is mostly on quantifying energy dissipation in compression and its effectiveness on seismic performance. Based on dynamic analyses of single story braced frame and case studies, it is found that a bracing member designed with bigger R and larger KL/r results in lower normalized cumulative energy, i.e., cumulative compressive energy normalized by the corresponding tensile energy (${\sum}E_C/E_T$), in both cases.

• Educational Technology International
• /
• v.22 no.2
• /
• pp.227-253
• /
• 2021

Perceived game realism (PGR) has recently emerged as a key concept in explaining the mental processing of digital game playing and the societal impact of digital games. However, few studies have examined its conceptualization and educational effects from an empirical viewpoint, especially in educational games. This study's participants included 292 university students in South Korea. A total of 212 questionnaires were valid and used for the analyses. They learned English expressions using a computer-based educational game and then completed questionnaires on the research variables. We investigated six factors of PGR: simulational realism (SIR), freedom of choice (FRC), perceptual pervasiveness (PEP), social realism (SOR), authenticity (AUT), and character involvement (CAI). We expected the factors to have valid effects on the university students' flow and learning satisfaction after a game-based learning (GBL) experience. Our research results demonstrated a causal relationship between SIR, FRC, CAI, and learning satisfaction. Furthermore, the indirect effects of SIR and CAI on learning satisfaction through flow were statistically significant.

• Earthquakes and Structures
• /
• v.22 no.3
• /
• pp.289-304
• /
• 2022

During strong ground motions, adjacent structures with insufficient separation distances collide with each other causing considerable architectural and structural damage or collapse of the whole structure. Generally, existing design procedures for determining the separation distance between adjacent buildings subjected to structural pounding are based on approximations of the buildings' peak relative displacement. These procedures are based on unknown safety levels. This paper attempts to evaluate the influence of foundation flexibility on the structural seismic response by considering the variability in the system and uncertainties in the ground motion characteristics through comprehensive numerical simulations. Actually, the aim of this study is to evaluate the influence of foundation flexibility on probabilistic evaluation of structural pounding. A Hertz-damp pounding force model has been considered in order to effectively capture impact forces during collisions. In total, 5.25 million time-history analyses were performed over the adopted models using an ensemble of 25 ground motions as seismic input within OpenSees software. The results of the study indicate that the soil-structure interaction significantly influences the pounding-involved responses of adjacent structures during earthquakes and generally increases the pounding probability.

• Wind and Structures
• /
• v.36 no.1
• /
• pp.31-40
• /
• 2023

This paper investigates the mechanical behavior of full-scale offshore fish cages under hydrodynamic loads. To simulate different cases, different materials were used in the fish cage and analyzed under different flow velocities. The cage system is studied in two parts: net cage and floating collar. Analyses were performed with the ANSYS Workbench program, which allows the Finite Element Method (FEM) and Computational Fluid Dynamics (CFD) method to be used together. Firstly, the fish cage was designed, and adjusted for FSI: Fluid (Fluent) analysis. Secondly, mesh structures were created, and hydrodynamic loads acting on the cage elements were calculated. Finally, the hydrodynamic loads were transferred to the mechanical model and applied as a pressure on the geometry. In this study, the equivalent (von Mises) stress, equivalent strain, and total deformation values of cage elements under hydrodynamic loads were investigated. The data obtained from the analyses were presented as figures and tables. As a result, it has been shown that it is appropriate to use all the materials examined for the net cage and the floating collar.

• Acta Via Serica
• /
• v.8 no.2
• /
• pp.53-78
• /
• 2023

The paper presents some new results illustrating some developments related to the concept of the Silk Road and subsequent methodological reflections. New laboratory results of scientific analyses of plants, minerals, and human remains in combination with more conventional methods of research contribute to a better understanding of the multidirectionality of exchanges in Pre- and Protohistory. Unsuspected long-distance transfers of items, especially of metals (tin) and biological materials (plants, pathogens, etc.) are discovered. Adding ancient DNA and petroglyphs to the vexed question of the Indo-European migrations across Eurasia complexifies the familiar linguistic, historical, and archaeological research landscape. Recent excavations show the impact of the adoption of artistic elements adapted from the Achaemenid arts, far in the steppe world, and up to China. Multidirectional (including North-South lanes) and multidisciplinary approaches leave space and hope for more rigorous scientific modelizations for the archaeology of Eurasia and the Silk Road.