• KIEAE Journal
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• v.13 no.6
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• pp.137-143
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• 2013

The purpose of this study is to suggest optimum micro-filler experiment method to select the optimal particle size of earth for using in earth construction works and test this suggestion through compressive strength measurement. According to the results of selecting the method to choose the optimum micro-filler mixing of earth and sand, three-stage filling(plate tamping) showed relatively high results and so was estimated to be the proper filling method. According to the results of optimum micro-filler experiment of earth and sand by the maximal sizes of sand, between 80% and 90% showed the highest result values. The larger the maximum size of sand was, the lower the addition ratio of sand was in optimum micro-filler mixing. According to the results of compressive strength experiment by the particle sizes of earth and sand, 90% in the addition ratio of sand showed the highest results, and so tended to be similar to the results of unit volume weight experiment.

• Korean Journal of Adult Nursing
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• v.26 no.6
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• pp.621-629
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• 2014

Purpose: The purpose of this study was to investigate the nutritional support, gastric residual volume, and nutritional status of the intensive care unit (ICU) patients on enteral feeding. Methods: A descriptive longitudinal design was used to collect 5 day data on enteral nutrition of 52 ICU patients in an university hospital. Nutritional support was calculated with actual caloric intake compared to individual caloric requirement. Residual volumes were measured prior to routine feedings, and the serum albumin levels and the total lymphocyte counts were checked to evaluate nutritional status. The data were analyzed using one group repeated measures ANOVA, paired t-test, and Spearman's bivariate correlation analysis. Results: The subjects received their first enteral feeding on the $5.75^{th}$ day of ICU admission. The mean nutritional support rate was 49.1% of the requirement, however prescription rate and support rate were increased as time goes by. Gastric residual volumes were less than 10 cc in 95% cases. A significant negative correlation was found between nutritional support and nutritional status. Conclusion: The nutritional support for ICU patient was low compared to the requirement, and their nutritional status was worse than at the time of ICU admission. Further studies are necessary to develop nursing interventions for improving nutritional support for ICU patients.

• Journal of the Korea Computer Graphics Society
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• v.18 no.4
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• pp.25-34
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• 2012

This paper presents a real-time GPU (graphics processing unit) ray casting scheme for rendering isosurfaces of BCC (body-centered cubic) volume datasets. A quartic spline field is built using the 7-direction box-spline filter accompanied with a quasi-interpolation prefilter. To obtain an interactive rendering speed on the graphics hardware, the shader code was optimized to avoid lookup table and conditional branches and to minimize data fetch overhead. Compared to previous implementations, our work outperforms the comparable one by more than 20% and the rendering quality is superior than others.

• Geomechanics and Engineering
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• v.12 no.6
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• pp.1021-1046
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• 2017

The assessment of slope stability is an essential task in geotechnical engineering. In this paper, a three-dimensional (3D) finite element analysis (FEA) was employed to investigate the performance of different shear pin arrangements to increase the stability of a soil block resting on an inclined plane with a low-interface friction plane. In the numerical models, the soil block was modeled by volume elements with linear elastic perfectly plastic material in a drained condition, while the shear pins were modeled by volume elements with linear elastic material. Interface elements were used along the bedding plane (bedding interface element) and around the shear pins (shear pin interface element) to simulate the soil-structure interaction. Bedding interface elements were used to capture the shear sliding of the soil on the low-interface friction plane while shear pin interface elements were used to model the shear bonding of the soil around the pins. A failure analysis was performed by means of the gravity loading method. The results of the 3D FEA with the numerical models were compared to those with the physical models for all cases. The effects of the number of shear pins, the shear pin locations, the different shear pin arrangements, the thickness and the width of the soil block and the associated failure mechanisms were discussed.

• BMB Reports
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• v.31 no.6
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• pp.600-603
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• 1998

A highly thermostable xylose isomerase from Thermus thermophilus has been expressed in Escherichia coli and crystallized. The purified enzyme shows its optimum temperature at $90^{\circ}C$. It has been crystallized at room temperature using polyethylene glycol 4000 as the precipitant. The crystal belongs to the orthorhombic space group $P2_12_12_1$, with unit cell parameters of a = 73.34 ${\AA}$, b = 144.05 ${\AA}$, c = 155.07 ${\AA}$. The presence of one molecule of tetrameric xylose isomerase in the asymmetric unit gives a crystal volume per protein mass ($V_m$) of 2.32 ${\AA}^3/Da$ and the solvent content of 47.0% by volume. The diffraction pattern extends to 1.9 ${\AA}$ Bragg spacing with synchrotron radiation and a set of native data has been collected to 2.3 ${\AA}$.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.04a
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• pp.184-187
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• 2003

Complete prediction of second order permeability tensor for three dimensional circular braided preform is critical to understand the resin transfer molding process of composites. The permeability can be predicted by considering resin flow through the multi-axial fiber structure. In this study, permeability tensor for a 3-D circular braided preform is calculated by solving a boundary problem of a periodic unit cell. Flow field through the unit cell is obtained by using a 3-D finite volume method (FVM) and Darcy's law is utilized to obtain permeability tensor. Flow analysis for two cases that a fiber tow is regarded as impermeable solid and permeable porous medium is carried out respectively. It is found that the flow within the intra-tow region of the braided preform is negligible if inter-tow porosity is relatively high but the flow through the tow must be considered when the porosity is low. To avoid checkerboard pressure field and improve the efficiency of numerical computation, a new interpolation function for velocity variation is proposed on the basis of analytic solutions. Permeability of the braided preform is measured through a radial flow experiment and compared with the permeability predicted numerically.

• Journal of The Korean Society of Agricultural Engineers
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• v.50 no.5
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• pp.39-50
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• 2008

This study are decided the mix proportion method of latex modified concrete for agricultural concrete structures from the results of workability and strength test with mix proportion factor. For mix proportion factor, this study are selected the water-cement ratio, unit cement amount and latex content. Also, this study were performed the slump, compressive strength test and microstructure analysis using the scanning electron microscope(SEM). The strength and slump of LMC are dependent with unit cement amount, latex content, and water-cement ratio. Especially, the strength of LMC are not controlled by single mix proportion factor but effected by combined mix proportion factor. Microstructure investigation are showed the LMC are reduced the internal pore volume and enhanced the transition zone between cement paste and aggregate interface. This effect get by consist of latex films in the concrete. Also, this study were recommended the mix proportion method for LMC. These mix proportions method are estimated the mix design for satisfied the target performance which are applied the agricultural concrete structure.

• Journal of the Korean Society of Industry Convergence
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• v.6 no.2
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• pp.115-122
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• 2003

This experimental study on high strength lightweight concrete using compound materials has been performed. In which, expanded clay was used as coarse aggregate, and silica fume and fly ash as admixtures varying by 0, 10% and 0, 5, 10, 15, 20% of cement amount respectively were added. Thus, the properties of fresh and hardened concrete have been investigated. The results of this study can be summarized as follows ; Each slump loss of mixtures replaced fly ash has been decreased by increasing replacement rate. The compressive strength have shown 465, 428 and $401kgf/cm^2$ at 30, 40 and 50% of W/B in 28days respectively, all of which have satisfied the criterion $270kgf/cm^2$ of high strength lightweight concrete. The unit volume weight of hardened concrete has been decreased by increasing replacement rate of silica fume and fly ash, values of which have satisfied the criterion $2000kgf/cm^3$of light weight concrete.

• Composites Research
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• v.17 no.2
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• pp.34-39
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• 2004

In this paper, a modified and representative unit cell model was employed to study the tensile behaviour of closed-cell metallic foams with varying spatial density distribution as well as material imperfections. The density variation was assumed to follow a statistical probability distribution of the Gaussian type. A multiple cell finite element model, utilising the modified unit cell, was developed. The model exhibits deformation patterns similar to those observed in tensile testing. The nominal stress-strain curve obtained from quasistatic tensile of the foam was compared with experimental findings and was found to be in good agreement in the scheme of maximum strength only if the appropriate density distribution and volume fraction of internal imperfections are taken into account. Moreover, maximum tensile strength of the aluminium foam was found to be more sensitive to the volume fraction of imperfection than standard deviation of the density.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.11a
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• pp.69-72
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• 2009

This research is focused on the applying of the foaming agent which can make the independent pore in the concrete structure in order to make a lightweight concrete structure. This lightweight foamed concrete can satisfy both the required strength and the mechanical properties as structural members. In addition, anti freezing-thawing properties also required. As a result of the unit volume-weight measurement, when the foaming agent mixed at 0.5% to 1%, the lightweight foamed concrete can be applied for the structural member. Also the density and compressive strength measurement results reveals that it will be suitable as structural member with 21MPa strength, when the density is betweenity8 to 1.9 and foaming agent quantities are 0.5% to 1%. Finally the result of freezing-thawing experiment, the effect freezing-thawing damage reduced according to adding foaming agent because those foaming agent make micro-pores in the structure which are not seen in the ordinary concrete structure.