• Geomechanics and Engineering
• /
• v.11 no.3
• /
• pp.385-400
• /
• 2016

Bearing capacity of open-ended piles depends largely on inner frictional resistance, which is influenced by the degree of soil plugging. While a fully-plugged open-ended pile produces a bearing capacity similar to a closed-ended pile, fully coring (or unplugged) pile produces a much smaller bearing capacity. In general, open-ended piles are driven under partially-plugged mode. The formation of soil plug may depend on many factors, including wall thickness at the pile tip (or inner pile diameter), sleeve height of the thickened wall at the pile tip and relative density. In this paper, we studied the effects of wall thickness at the pile base and sleeve height of the thickened wall at the pile tip on bearing capacity using laboratory model tests. The tests were conducted on a medium dense sandy ground. The model piles with different tip thicknesses and sleeve heights of thickened wall at the pile tip were tested. The results were also discussed using the incremental filling ratio and plug length ratio, which are generally used to describe the degree of soil plugging. The results showed that the bearing capacity increases with tip thickness. The bearing capacity of piles of smaller sleeve length (e.g., ${\leq}1D$; D is pile outer diameter) was found to be dependent on the sleeve length, while it is independent on the sleeve length of greater than a 1D length. We also found that the soil plug height is dependent on wall thickness at the pile base. The results on the incremental filling ratio revealed that the thinner walled piles produce higher degree of soil plugging at greater penetration depths. The results also revealed that the soil plug height is dependent on sleeve length of up to 2D length and independent beyond a 2D length. The piles of a smaller sleeve length (e.g., ${\leq}1D$) produce higher degree of soil plugging at shallow penetration depths while the piles of a larger sleeve length (e.g., ${\geq}2D$) produce higher degree of soil plugging at greater penetration depths.

• Korean Journal of Ichthyology
• /
• v.8 no.1
• /
• pp.49-55
• /
• 1996

The growth of total length(TL), total weight(TW) and somatic weight(SW) of rainbow trout, Oncorhynchus mykiss alevin at yolk absorption period was expressed by the Gompertz growth model as $TLt=2.7e^{-1.24{\cdot}e^{-0.11t}}(r^{2}=0.66)$, $TWt=1.8e^{-2.03{\cdot}e^{-0.11t}}(r^{2}=0.66)$ and $SWt=1.8e^{-5.41{\cdot}e^{-0.13t}}(r^{2}=0.83)$ respectively. Yolk length, yolk height and yolk volume of rainbow trout decreased linearly. The relative growth of total weight-total length, somatic weight-total length, yolk length-total length, yolk height-total length, yolk volume-total length, yolk weight-total length, yolk weight-total weight, yolk weight-yolk height and yolk weight-yolk length at yolk absorption period revealed the pattern of yolk absorption in rainbow trout.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.32 no.4
• /
• pp.651-658
• /
• 2008

Conjoint analysis estimates how much each of the attributes is valued on the basis of the choices consumers make among product concepts that are varied in systematic ways. The purposes of this research were to evaluate the relative importance of each fabric constituent characteristic for the consumer's utility or preference, to compare with the relative importance between the trained and the untrained panelists, and to identify the combinations of the constituent characteristic of knit fabric which offer consumers greater utility. Conjoint analysis was conducted using data taken from 54 trained and 54 untrained panelists, who rated preference for 12 different knit fabrics. The stitch length had a greater effect on knit fabric preference than the mixture ratio of fiber. There was no difference on effect of knit constituent characteristics for preference between the trained and the untrained panelists. Total, trained and untrained group preferred a knit fabric that had a higher acrylic mixture ratio and a short stitch length.

• Journal of the Korean Society for Precision Engineering
• /
• v.29 no.1
• /
• pp.64-71
• /
• 2012

In this paper, a parallel manipulator is comprised of two sliders and four links. Sliders execute a linear reciprocating motion depending on parallel guides and make the connected links rotate. A couple of links connected by sliders do coupling motion. The end-effector called a link tip has orientation angle. Through the kinematics analysis of this manipulator, we found displacement, velocity and acceleration using direct and inverse kinematics. We used equations that derived from this analysis and determined five constraint conditions. These conditions had much to do with rotation states of links, the relative relation of link length and coupling motion state. To verify those, we suggest a new algorithm regarding constraint conditions of a manipulator. With the result which performed the algorithm, we found out that operation range of coupled links was limited by relative relation of link length and that manipulator was not able to carry out a series of link motion, in case of being the link vertical between two parallel guides.

• Korean Journal of Poultry Science
• /
• v.16 no.4
• /
• pp.201-207
• /
• 1989

This study was carried out to identify the chromosome morphological structure and G-, C-banding pattern of Korean native fowl. The samples used in this study were early chick embryos, and the method of chromosomal analysis quoted from the protocal of Ohio univ. with more or less modified. The results were summerized as follow as； 1. In each of macrochromosomal morphology, the arm-ratio, centromeric index, and relative length of Korean native fowl were more or less different from improved breeds, but the designations were the same. 2. The graphical pecks, by densitometric recordings, in each macrochromosome number of 1, 2, 3, 4, Z, and 5, numbered 21, 14, 12, 8, 11, and 4 in G-banded, and 16, 13, 9, 9, 9, and 4 in C-banded, respectively. Those pecks could be explained as a consequence of chromosome condensation during mitosis and of genetic material differences.

• Asian-Australasian Journal of Animal Sciences
• /
• v.15 no.3
• /
• pp.321-325
• /
• 2002

Karyotype analysis was carried out on blood samples of 30 water buffaloes belonging to different breed groups (i.e. Philippine Carabao (PC), Indian Murrah (IM), Bulgarian Murrah (BM), "$F_1$ 50% IM-50% PC", "$F_1$ 50% BM-50% PC" and "75% IM-25% PC"), using the modified Leucocyte Culture Technique. The modal chromosome numbers of the PC, "$F_1$ 50% IM-50% PC", "$F_1$ 50% BM-50% PC", IM, BM and "75% IM-25% PC" were 2n=48, 49, 49, 50, 50 and 50, respectively. The water buffalo chromosomes are mostly acrocentric (79.67%) and the remainder submetacentric (20.33%). Results of the ordinary least square analysis showed significant breed effects (p<0.01) on other karyotypic characteristics (i.e. relative length, arm ratio and centromeric index). Significant correlation between karyotypic characteristics and some animal performance traits were also found. The significant correlation values imply that karyotypic characteristics can be used as important criteria to select potentially productive young water buffaloes. In the future, more production and reproduction traits from non-institutional herds should be included in the analysis to reveal meaningful correlations with various karyotypic characteristics.

• Journal of Korean Academy of Nursing Administration
• /
• v.16 no.4
• /
• pp.399-408
• /
• 2010

Purpose: The purpose of this study was to compare the cost using different methods of costing nursing activities for patients with chronic otitis media having surgery. Method: Data were collected from 30 patients who had mastoidectomy and tympanoplasty. To compare the cost, the researchers used three different costing methods; consumed time, resource based relative value scale (RBRVS), and critical pathway (CP). Results: Twenty-six nursing activities for surgical patients with chronic otitis media were found. Total cost was 83,843.7 won using RBRVS. The costliest activity was recording at 9,734.4 won, followed by confirmation of doctors' orders at 9,302.4 won, and injection with infusion pump at 9,072.0 won. There was a difference in nursing activities performed according to the length of hospital stay, and the cost was highest on the surgery day at 13,417.8 won. Comparatively, the total cost was 72,014.4 won using CP. Conclusions: Nursing activities are performed in various forms according to the disease and patient's condition, and different nursing activities are executed according to the length of hospital stay. In order to measure the load of nursing activities and distribute it appropriately, it is necessary to analyze the cost of nursing activities by the process of nursing services performed.

• Journal of the Korean Magnetics Society
• /
• v.21 no.3
• /
• pp.99-103
• /
• 2011

In this study, we have performed systematical FEM analysis for design of open-ended 3-layer magnetic shield. For the simulation to calculated shielding factors, the relative permeability was varied in the range of $2{\times}10^3\sim1{\times}10^5$, and the length of the magnetic cylinders and length difference between layers were changed. We found that the shielding factor of -60 dB were obtained with the relative permeability of over 20000 and the lengths of magnetic layers of 40 cm, 45 cm and 50 cm, and the uniform magnetic field could be obtained in the range of $10cm{\times}10cm-\phi$.

• Journal of the Korean Society for Railway
• /
• v.5 no.4
• /
• pp.260-266
• /
• 2002

A numerical simulation has been performed to estimate the transient pressure variation in the tunnel when G7 test train passes through the test tunnel in the Kyoeng-Bu high-speed railway. A modified patched grid scheme is developed to handle the relative motion between a train and a tunnel. Also, a hybrid dimensional approach is proposed to calculate the train-tunnel interaction problem efficiently. An axi-symmetric unsteady Euler solve using the Roe's FDS is used for analyzing a complicated pressure field in tunnel during the test train is passing through the tunnel. Usually, this complex phenomenon depends ell the train speed, train length, tunnel length, blockage ratio between train and tunnel cross-sectional area, relative position between train and tunnel, etc. Therefore, numerical simulation should be done carefully in consideration of these factors. Numerical results in this study would be good guidance to make test plans, test equipments selection and to decide their measuring locations. They will also supply important information to the pressurization equipment for high-speed train.

• Steel and Composite Structures
• /
• v.25 no.5
• /
• pp.603-615
• /
• 2017

This experimental research presents the seismic performance of steel reinforced high-strength concrete (SRHC) short columns. Eleven SRHC column specimens were tested under simulated earthquake loading conditions, including six short column specimens and five normal column specimens. The parameters studied included the axial load level, stirrup details and shear span ratio. The failure modes, critical region length, energy dissipation capacity and deformation capacity, stiffness and strength degradation and shear displacement of SRHC short columns were analyzed in detail. The effects of the parameters on seismic performance were discussed. The test results showed that SRHC short columns exhibited shear-flexure failure characteristics. The critical region length of SRHC short columns could be taken as the whole column height, regardless of axial load level. In comparison to SRHC normal columns, SRHC short columns had weaker energy dissipation capacity and deformation capacity, and experienced faster stiffness degradation and strength degradation. The decrease in energy dissipation and deformation capacity due to the decreasing shear span ratio was more serious when the axial load level was higher. However, SRHC short columns confined by multiple stirrups might possess good seismic behavior with enough deformation capacity (ultimate drift ratio ${\geq}2.5%$), even though a relative large axial load ratio (= 0.38) and relative small structural steel ratio (= 3.58%) were used, and were suitable to be used in tall buildings in earthquake regions.