• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.10
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• pp.490-498
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• 2020

In this study, the seismic performance of low-rise piloti buildings with eccentric core (shear wall) positions was analyzed and reviewed. A prototype was selected among constructed low-rise piloti buildings with eccentric cores designed based on KBC2005. The seismic performance of the building showed plastic behavior in the X-direction and elastic behavior in the Y-direction. The inter-story drift is larger than that of a concentric core case and has the maximum allowed drift ratio. The displacement ratio of the first story is much larger than that of upper stories, and the frame structure in the first story is vulnerable to lateral force. Therefore, low-rise piloti buildings with eccentric cores need to have less lateral displacement, as well as reinforcement of the lateral resistance capacity in seismic design and seismic retrofit.

• Journal of Oral Medicine and Pain
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• v.36 no.3
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• pp.161-167
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• 2011

Sialolith is one of the most common pathologic conditions found in the salivary glands. The mechanisms responsible for the formation of sialoliths have not been elucidated so far. In this article, the chemical composition and micromorphology of a sialolith of a 58-year old female patient suffering from chronic sialoadenitis of the submandibular gland was analyzed using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). In a SEM evaluation, the highly mineralized amorphous core surrounded by lamellar and concentric structures was revealed, however no foreign body, organic material, or signs of microorganism were observed in the core of the sialolith. EDX analysis showed the central core was composed of only Ca, O and P, and that a high level of C was detected near the central area as well. These results indicated that the inorganic composition of the sialolith was hydroxyapatite crystals, and that inorganic and organic substances existed around the central cores. This study suggests that the sialolith was composed mainly of hydroxyapatite crystals and the formation of the nucleus of the sialolith in the submandibular gland duct was secondary to sialadenitis, which favors the growth of an inorganic crystalline nucleus.

• Journal of Korean Society of Steel Construction
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• v.24 no.4
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• pp.361-369
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• 2012

In this study, prefabricated composite columns using high-strength angles (PSRC composite column) was studied. Concentric axial loading tests were performed for 2/3 scale PSRC specimens and an conventional SRC specimen with H-steel at the center of the cross-section. The test parameters were the steel ratio of angles and the spacing of lateral re-bars. The test results showed that by placing the angles at the corners of the cross-section for confinement with provided for the core concrete, the PSRC column specimens exhibited greater load-carrying capacity and deformation capacity than those of the conventional SRC column. The axial load-carrying capacity of the PSRC columns was greater than the prediction by KBC 2009. Using existing stress-strain relationship of confined concrete, the axial load-deformation relationship of the specimens were predicted. The numerical predictions correlated well with the test results in terms of initial stiffness, load-carrying capacity, and post-peak strength- and stiffness-degradations.

• Economic and Environmental Geology
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• v.14 no.1
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• pp.27-33
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• 1981

The manganese nodule from the Blake Plateau consists mainly of microcrystalline to cryptocrystalline todorokite, with minor quartz, clays, carbonates and phillipsite. The nodule in cross section shows concentric layers, core structure, unconformity and fissure-filling structure megascopically, and colloform, fragmental and diagenetic textures microscopically. A new classification of colloform textures which are applicable to any nodule of any source shows that the colloform textures consist of three basic textural units: banded, cuspate and globular. They occur independently or in combination with each other to form various types of textures. The presence of three predominant textural types suggests that there are three different major modes of nodule growth which are controlled by physical and chemical environments.

• Tunnel and Underground Space
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• v.8 no.3
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• pp.226-233
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• 1998

Microcracks in rock materials, whether natural or induced, provide useful information on the engineering performance of in situ rockmasses. A population of preferentially oriented microcracks has observable effects on the physical properties of a rockmass, but their effects may not be evident if the rock material is highly anisotropic due to other causes. An experimental program was undertaken to investigate the effect of rock fabrics on the physical properties of rock materials. In this study, anisotropy in the circumferential wave velocity and the direction of induced fractures under axial point loading were measured. Rock specimens (NX-size) of the leucocractic Pocheon granite were cored from rock blocks, retaining the relative directions of each specimen. Another set of specimens was prepared from the rock cores of the same meterial, obtained in the field. The master orientation line (MOL) was set to be the representative direction of the microcracks in the specimen. Variation of the circumferential wave velocity of each specimen was then measured along the core, keeping the MOL as reference. The direction of the minimum wave velocity was nearly perpendicular to the direction of the MOL. Coring of smaller-sized (EX-size), concentric specimens from the NX specimens were then followed, and axial point loading was applied. The direction of induced fractures due to axial point loading was closely related to the MOL direction, confirming the prior test result.

• Computers and Concrete
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• v.25 no.5
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• pp.383-400
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• 2020

Due to higher stiffness to weight, higher corrosion resistance, higher strength to weight ratios and good durability, concrete composite structures provide many advantages as compared with conventional materials. Thus, they have wide applications in the field of concrete construction. This research focuses on the structural behavior of steel-tube CFRP confined concrete (STCCC) columns under axial concentric loading. A nonlinear finite element analysis (NLFEA) model of STCCC columns was simulated using ABAQUS which was then, calibrated for different material and geometric models of concrete, steel tube and CFRP material using the experimental results from the literature. The comparative study of the NLFEA predictions and the experimental results indicated that the proposed constitutive NLFEA model can accurately predict the structural performance of STCCC columns. After the calibration of NLFEA model, an extensive parametric study was performed to examine the effects of different critical parameters of composite columns such as; (i) unconfined concrete strength, (ii) number of CFRP layers, (iii) thickness of steel tube and (iv) concrete core diameter, on the axial load capacity. Furthermore, a large database of axial strength of 700 confined concrete compression members was developed from the previous researches to give an analytical model that predicts the ultimate axial strength of composite columns accurately. The comparison of the predictions of the proposed analytical model was done with the predictions of 216 NLFEA models from the parametric study. A close agreement was represented by the predictions of the proposed constitutive NLFEA model and the analytical model.

• Structural Engineering and Mechanics
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• v.22 no.5
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• pp.541-562
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• 2006

This paper compares the performance of axially loaded concrete filled steel tube (CFST) columns cast using a conventionally vibrated normal concrete (NC) and a novel self-consolidating concrete (SCC) made with a new viscosity modifying admixture (VMA). A total of sixteen columns with a standard compressive strength of about 50 MPa for both SCC and NC were tested by applying concentric axial load through the concrete core. Columns were fabricated without and with longitudinal and hoop reinforcement (Series I and Series II, respectively) in addition to the tube confinement. The slenderness of the columns expressed as height to diameter ratio (H/D) ranged between 4.8 and 9.5 for Series CI and between 3.1 and 6.5 for Series CII. The strength and ductility of SCC columns were found comparable to those of their NC counterparts as the maximum strength enhancement in NC columns ranged between 1.1% and 7.5% only. No significant difference in strain development was found due to the presence of SCC or NC or due to the presence of longitudinal and hoop reinforcement. Biaxial stress development in the steel tube as per von Mises yield criterion showed similar characteristics for both SCC and NC columns. The confined strength ($f^{\prime}_{cc}$) of SCC was found to be lower than that of NC and $f^{\prime}_{cc}$ also decreased with the increase of slenderness of the columns. Analytical models for the prediction of confined concrete strength and axial strength of CFST columns were developed and their performance was validated through test results. The proposed models were found to predict the axial strength of CFST columns better than existing models and Code based design procedures.

• Journal of the Earthquake Engineering Society of Korea
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• v.7 no.2
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• pp.21-27
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• 2003

In general, simple fluid added mass method is used for the seismic and vibration analysis of the immersed structure to consider the fluid-structure interaction effect. Actually, the structural response of the immersed structure can be affected by both the fluid added mass and damping caused by the fluid viscosity. These variables appeared as a consistent matrix form with the coupling terms. In this paper, finite element formula for the inviscid fluid case and viscous fluid case are derived from the linearized Navier Stoke's equations. Using the finite element program developed in this paper, the analyses of fluid added mass and damping for the hexagon core structure of the liquid metal reactor are carried out to investigate the effect of fluid viscosity with variation of the fluid gap and Reynolds number. From the analysis results, it is verified that the viscosity significantly affects the fluid added mass and damping as the fluid gap size decrease. From the analysis results of eccentricity effect on the fluid added mass and damping of the concentric cylinders, the fluid added mass increase as the eccentricity increases, however the fluid damping increases only when the eccentricity is very severe.

• The Journal of the Petrological Society of Korea
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• v.22 no.3
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• pp.219-233
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• 2013

Spherulitic rhyolite occur as part of ring dyke which showing a vertical flowage of $60^{\circ}{\sim}90^{\circ}$, of the Jangsan cauldron was studied. The spherulites range in diameter from a few millimeters to 2.8 centimeters or more, and average 5~10 millimeters. It belongs to radiated simple spherulite type. They consist of a core of moderate brown dense material encased by a thin crust, a few millimeters thick at most of white grey material. The spherulites frequently have a radiating fibrous structure, which are thought to have formed as a consequence of rapid mineral growth caused by very fast cooling of the dykes in shallow depth near the surface. EPMA examination of the concentric-zoned core of spherulites show that they are mainly composed of cryptocrystalline-fibrous intergrowth of silica minerals and alkali feldspars which have $SiO_2$ 82% or more, $Al_2O_3$ 7~10%, $Na_2O+K_2O$ less than 8%. The feldspar compositions of the spherulites lie essentially within the sanidine field. XRD examination show that spherulites are mainly composed of quartz, sanidine, albite with minor mica, kaolinite and chlorite. According to X-ray mapping, the spherulites are enriched in $SiO_2$ in the core and partly enriched $Na_2O$ or $K_2O$, $Al_2O_3$ in the shell that reflect in compositional zoning with increasing spherulitic devitrification. The feathery and non-equant crystal shapes of spherulites from rhyolite dyke of Jangsan cauldron suggest that they may have formed during the rapid cooling of dyke under the static state, or faster velocity of devitrification from glassy materials than movement velocity of the magma intrusion. The spherulitic rhyolite originated from high-silica(75.4~75.7 wt.%) rhyolite magma.

• Journal of Korean Academy of Nursing
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• v.27 no.4
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• pp.933-942
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• 1997

There has recently been an increased interest in women's health from, various disciplines, with different perspectives presented according to each profession's academic background. This has led to many instances of incorrectly defining, or misinterpretation, of the issues even among professionals. Nurse scholars as well as practitioners who work in women's health care need to have a clear conceptual understanding of women's health in order to build a body of knowledge, delineate curricular activities, and set directions for professional nursing interventions. In addition, a conceptual model that may be directly utilized in practice is needed to maintain and promote women's health issues. The purpose of this study was to apply a Hybrid model, analyzing conceptual definitions and discussions related to women's health gathered from review of the literature. Further to compare analyticals the concepts and properties observed from field work, so as to present a final definition of women's health and, build a conceptual framework for a united comprehensive perspective on the concept as well as on nursing practice. Data collection and analysis consisted of a theoretical stage, field work stage, and final analysis. A heterogeneous group of professionals and lay persons, 39 in all, participated in the field work. Study findings Include several subconcepts under the concept of women's health : a woman's whole life, holistic health, quality of life, awareness of being a woman, individual nursing, self care ability, reproductive health, and family health. Thus, a comprehensive definition was built, 1. e., "Women's health care be defined as improvement in the quality of life of women through attainment of holistic health throughout the life span. With reproductive health at the core, the concept is directly related to family and national health, and includes taking care of one's own health based on awareness of being a woman and utilizing self care activities. Women's health care issues are unique and allow various responses, therefore women's health professionals need to apply individual approaches to reach solutions in attaining holistic health and improving quality of life." The constructual factors of women's health were found to be reproductive functions, diseases more common in woman, self actualization, mental health, women's health policies, sexuality, midlife changes, and marital relations, with each factor having more than three properties. Positive factors affecting women's health were found to be a normal childbearing process, a healthy lifestyle, active health management, health information, support, and resources, and interpersonal relationships. Negative factors were found to be overwhelming role stress, cultural oppression, gender inequality, distorted sexual identity, economic difficulties, misuse and/or abuse of substances, and stress. The model of women's health may be visualized as a balance scale set upon a woman's life, supporting 4 concentric circles. The innermost circle and second circle incorporate conceptual definitions of women's health, and the outer two circles represent the constructional factors and properties of women's health. Each circle has its own color that symbolizes the conceptual meaning. Positive and negative factors are represented as weights at either end of the scale, and are affected by nursing intervention, i. e., health and wellness increase when positive factors are stronger, whereas disease and illness increase when negative factors are stronger. This model is only a preliminary effort and requires much discussion and testing to be further developed. Continuous research is also required.