• Proceedings of the Korea Concrete Institute Conference
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• 2000.10b
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• pp.1001-1006
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• 2000

These should be constructed partially, because many prestressed concrete box girder bridges in situ have large cross section and long span. Therefore, accurate prediction of differences, both elapse time of each construction stage and exposure of atmosphere at each position of cross section, is very important. Though it is importance, engineers are apt to overlook it. This study predicted cracks due to shrinkage and stress concentration phenomenon by each construction stage and then, ascertained reduction of tensile stresses after applying retrofit scheme.

• Journal of Fashion Business
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• v.10 no.5
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• pp.105-121
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• 2006

Body measurement was first made with the subjects of 193 males in their 20s residing in the Ningbo area, Zhejiang Province in China. In this first report, lower body shapes were classified and discriminated by using anthropometric measurement indices and lower body analysis. The following sums up the research: 1. Compared with the average values of Korean males in their 20s, the Chinese subjects were characterized with thinner waist, more flat hip, and smaller midthigh. 2. The subjects of Chinese males in their 20s showed three types of lower bodies: H-Round Type (25.91%)-thick waist-abdomen, round cross-section waist-abdomen, and small waist-hip difference. A-Trapezoid Type (34.72%)-small width of omphalion waist-abdomen, average cross-section waist-abdomen, and large waist-hip difference. A-Balance Type (39.38%)-average width of omphalion waist-abdomen, flat cross-section waist-abdomen, and large waist-hip difference. 3. Seven useful variables for the categorization of the subjects' lower body types were chosen through stepwise discriminant analysis, and the hit ratio of discrimination was 96.89%.

• Steel and Composite Structures
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• v.13 no.1
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• pp.71-89
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• 2012

The paper investigates beam lateral buckling stability according to linear and non-linear models. Closed form solutions for single-symmetric cross sections are first derived according to a non-linear model considering flexural-torsional coupling and pre-buckling deformation effects. The closed form solutions are compared to a beam finite element developed in large torsion. Effects of pre-buckling deflection and gradient moment on beam stability are not well known in the literature. The strength of singly symmetric I-beams under gradient moments is particularly investigated. Beams with T and I cross-sections are considered in the study. It is concluded that pre-buckling deflections effects are important for I-section with large flanges and analytical solutions are possible. For beams with T-sections, lateral buckling resistance depends not only on pre-buckling deflection but also on cross section shape, load distribution and buckling modes. Effects of pre-buckling deflections are important only when the largest flange is under compressive stresses and positive gradient moments. For negative gradient moments, all available solutions fail and overestimate the beam strength. Numerical solutions are more powerful. Other load cases are investigated as the stability of continuous beams. Under arbitrary loads, all available solutions fail, and recourse to finite element simulation is more efficient.

• International Journal of Highway Engineering
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• v.8 no.2 s.28
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• pp.75-85
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• 2006

Currently, cross-section design can not reflect highway function and traffic volume, various construction. This research paper provides analysis of traffic accident type, improvement of traffic operation and safety, assessment for new cross-section standards of two-lane highway. Research show higher accident rate on 6$\sim$8.9m road than 9$\sim$12.9m road width in two-lane highway. Typical improvement is widening on lane and shoulder width. Simulation show large increase on 6$\sim$7m road delay-time in 1,200vph. In contrast 10$\sim$11.5m road shows slight change on delay-time. This research paper provides various cross-section construction by traffic volume in minor arterial and distributor two-lane highway. The new cross-section design provides adopting highway volume, various construction and flexibility.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.1
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• pp.149-157
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• 1999

Heat transfer in a duct is augmented remarkably by rib turbulators. However, increasing friction loss is accompanied due to ribs disturbing flows. Hence, pressure drops and heat transfer are considered simultaneously to decide heat/mass transfer performance in a rib-roughened duct. In the present study, the effects of rib cross section shape on pressure drop through a duct are investigated as well as those on heat transfer characteristics. The results show that the characteristics of heat/mass transfer and friction loss in the duct roughened with triangular ribs are similar to those with square ribs, while significantly different from those with semicircular ribs. The best performance in the duct is obtained by using semicircular shaped ribs among three types of ribs for the large rib angles of ${\alpha}{\geq}63^{\circ}$.

• Journal of Ocean Engineering and Technology
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• v.24 no.1
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• pp.34-38
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• 2010

An analytical solution procedure for the dynamic response of beams with variable properties is developed by using an asymptotic solution and the Green's function. This asymptotic closed form solution is derived for the transverse vibration of beams under the assumption of slowly varying properties, such as mass, cross-section, tension etc., along the beam length. However, this solution is still found to be very accurate even in the case of large variation, such as step change in cross-section, mass, and tension. Therefore, this derived asymptotic closed form solution and the Green's function can be easily applied to find dynamic responses for various kind of beam vibration problems.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.12
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• pp.3063-3068
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• 2014

Since the RCS(Radar Cross Section) of target is important factor to determine radar performance, it is important to locate radar where large RCS is observed. However, the distance between the target and the radar is an important factor of the received power, as well as RCS. In this paper, it is calculated that received power from ballistic missile to radar based on different observed position and it is studied that to place radar for high detection efficiency.

• Steel and Composite Structures
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• v.45 no.1
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• pp.39-49
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• 2022

This research investigates a rotary disk with variable cross-section and incompressible hyperelastic material with functionally graded properties in large hyperelastic deformations. For this purpose, a power relation has been used to express the changes in cross-section and properties of hyperelastic material. So that (m) represents the changes in cross-section and (n) represents the manner of changes in material properties. The constants used for hyperelastic material have been obtained from experimental data. The obtained equations have been solved for different m, n, and (angular velocity) values, and the values of radial stresses, tangential stresses, and elongation have been compared. The results show that m and n have a significant impact on disk behavior, so the expected behavior of the disk can be obtained by an optimal selection of these two parameters.

• Nuclear Engineering and Technology
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• v.52 no.12
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• pp.2733-2742
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• 2020

This paper presents an assessment of applicability of the multigroup cross sections generated with Monte Carlo tools to the fast reactor analysis based on transport calculations. 33-group cross section sets were generated for simple one- (1-D) and two-dimensional (2-D) sodium-cooled fast reactor problems using the SERPENT code and applied to deterministic steady-state and depletion calculations. Relative to the reference continuous-energy SERPENT results, with the transport corrected P₀ scattering cross section, the k-eff value was overestimated by 506 and 588 pcm for 1-D and 2-D problems, respectively, since anisotropic scattering is important in fast reactors. When the scattering order was increased to P₅, the 1-D and 2-D problem errors were increased to 577 and 643 pcm, respectively. A sensitivity and uncertainty analysis with the PERSENT code indicated that these large k-eff errors cannot be attributed to the statistical uncertainties of cross sections and they are likely due to the approximate anisotropic scattering matrices determined by scalar flux weighting. The anisotropic scattering cross sections were alternatively generated using the MC²-3 code and merged with the SERPENT cross sections. The mixed cross section set consistently reduced the errors in k-eff, assembly powers, and nuclide densities. For example, in the 2-D calculation with P3 scattering order, the k-eff error was reduced from 634 pcm to -223 pcm. The maximum error in assembly power was reduced from 2.8% to 0.8% and the RMS error was reduced from 1.4% to 0.4%. The maximum error in the nuclide densities at the end of 12-month depletion that occurred in ²³⁷Np was reduced from 3.4% to 1.5%. The errors of the other nuclides are also reduced consistently, for example, from 1.1% to 0.1% for ²³⁵U, from 2.2% to 0.7% for ²³⁸Pu, and from 1.6% to 0.2% for ²⁴¹Pu. These results indicate that the scalar flux weighted anisotropic scattering cross sections of SERPENT may not be adequate for application to fast reactors where anisotropic scattering is important.

• Nuclear Engineering and Technology
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• v.35 no.6
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• pp.581-595
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• 2003

Transport lattice codes require the resonance integral tables for the resonant nuclides where the resonance integral is a function of the background cross section and can be prepared through a special program solving the slowing down equation. In case the cross section libraries do not include the resonance integral table for the resonant nuclides, the computational prediction produces a large error. We devised a new method using a Monte Carlo calculation for the effective resonance cross sections to solve this problem provisionally. We extended this method to obtain the resonance integral table for general purpose. The MCNP code is used for the effective resonance integrals and the LIBERTE code for the effective background cross sections. We modified the HELIOS library with the effective cross sections and the resonance integral tables obtained by the newly developed Monte Carlo method, and performed sample calculations using HELIOS and LIBERTE. The results showed that this method is very effective for the resonance treatment.