• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.1406-1412
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• 2001

Roof racks have become a very popular feature of vehicles as the market demand for SUV's and RV's has increased drastically over the years. Aeolian tone from the cross bars however. could be a source of severe discomfort for the passengers. Both experimental and numerical steps are taken to enhance the understanding of the generation mechanism of the wind noise. A successful reduction of the noise is achieved by imposing asymmetry in the section geometry, which reduces the strength of Karmann vortices shed downstream.

• Steel and Composite Structures
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• v.33 no.1
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• pp.133-142
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• 2019

In the present study, microstructure-dependent static stability analysis of inhomogeneous tapered micro-columns is performed. It is considered that the micro column is made of functionally graded materials and has a variable cross-section. The material and geometrical properties of micro column vary continuously throughout the axial direction. Euler-Bernoulli beam and modified couple stress theories are used to model the nonhomogeneous micro column with variable cross section. Rayleigh-Ritz solution method is implemented to obtain the critical buckling loads for various parameters. A detailed parametric study is performed to examine the influences of taper ratio, material gradation, length scale parameter, and boundary conditions. The validity of the present results is demonstrated by comparing them with some related results available in the literature. It can be emphasized that the size-dependency on the critical buckling loads is more prominent for bigger length scale parameter-to-thickness ratio and changes in the material gradation and taper ratio affect significantly the values of critical buckling loads.

• Nuclear Engineering and Technology
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• v.53 no.12
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• pp.4067-4071
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• 2021

The ¹³C (α,n)¹⁶O reaction cross-section is important data for nuclear physics, astrophysical, and neutrino physics experiments, however, they exhibit uncertainties due to the discrepancies in the experimental data. In this study, using the Nedis-2m program code, the energy spectrum of α-induced neutrons in a thin carbon target was calculated and the corresponding reaction cross-section was refined in the alpha particle energy range of 5-8 MeV. The results were used to calculate the intensity and energy spectrum of background neutrons produced in the liquid scintillator of KamLAND. The results will be useful in a variety of astrophysical and neutrino experiments especially those based on LS or Gd-LS detectors.

• Journal of Ocean Engineering and Technology
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• v.35 no.3
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• pp.238-246
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• 2021

The survivability of a naval ship is the ability of the ship and its onboard systems to remain functional and continue a designated mission in man-made hostile environments. A passive decoy system is primarily used as a weapon system for improving the survivability of a naval ship. In this study, an engagement scenario-based simulation program was developed for decoy effectiveness assessments against an anti-ship missile (ASM), which tracks a target with sea-skimming and active radar homing. The program can explain the characteristics of a target ship, such as the radar cross section and evasive maneuvers, as well as the operational performance of the onboard decoy system, the guidance method of the ASM, and the engagement environment's wind speed and direction. This paper describes the theory and formulations, configuration, and user interface of the developed program. Numerical examples of a decoy effect assessment of a virtual naval ship against an ASM are presented.

• Nuclear Engineering and Technology
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• v.55 no.1
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• pp.229-237
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• 2023

The mechanics underlying photon and electron interactions was validated using our developed Brachytherapy computer code for high Dose Rate (HDR). By comparing the photon cross-section utilizing multiple physics libraries in the developed code, the results were benchmarked against experimental and theoretical findings. Klein-Nishina and experimental cross-section results were in good agreement with the Livermore library results. For two therapeutically relevant materials, the first scattered electron range was measured within 1 mm and 2 mm, which has significant implications for the interpretation of the kernel dose spikes observed in previous research.

• 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.

• Journal of Acupuncture Research
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• v.30 no.4
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• pp.45-53
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• 2013

Objectives : The purpose of this study was to evaluate the relationship between cross-sectional areas of the paraspinal and psoas muscles with low back pain. Methods : We assessed the cross-sectional area of the psoas and paraspinal muscles at the superior part of L4 level and vertebral body of L4 of 132 patients who were hospitalized with a chief complaint of low back pain at Jaseng Hospital of Korean Medicine from January 2013 to April 2013. After calculating the mean psoas area, we divided the patients into 2 groups by whether the psoas cross section was larger or smaller than the mean, and compared the admission period, verbal numeric rating scale(NRS) of low back pain(LBP), and improvement of verbal NRS of LBP. We also subcategorized the patients into acute and chronic groups according to the duration period, and compared the cross-sectional area of the psoas and paraspinal muscles. Results : Although analyses of the verbal NRS of LBP, and improvement of verbal NRS of LBP between groups with larger and smaller psoas cross section areas showed no significant difference, the admission period was significantly shorter in the group with larger psoas cross section areas. There was no significant difference in analyses of cross section areas in the acute and chronic groups. Of the possible prognostic variables, improvement of verbal NRS of LBP showed no correlation, while the admission period displayed a significant correlation. The cross-sectional area of the psoas and paraspinal muscles divided by the area of the vertebral body of L4 had a significant negative correlation with age. Conclusions : The cross-sectional area of the psoas and paraspinal muscles were correlated with the admission period in LBP patients, and the cross-sectional area of the surrounding muscles divided by the area of the L4 vertebral body was negatively correlated with age.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.19 no.1
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• pp.47-56
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• 2015

In this paper, we present an implicit method for reconstructing a 3D solid model from two 2D cross section images. The proposed method is based on the Cahn-Hilliard model for the image inpainting. Image inpainting is the process of reconstructing lost parts of images based on information from neighboring areas. We treat the empty region between the two cross sections as inpainting region and use two cross sections as neighboring information. We initialize the empty region by the linear interpolation. We perform numerical experiments demonstrating that our proposed method can generate a smooth 3D solid model from two cross section data.

• 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.

• Journal of the Korean Professional Engineers Association
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• v.16 no.4
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• pp.4-14
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• 1983

when one is designing a continuous bridge with variable cross sections, it is very troublesome to integrate explicitly load terms and various factor under consideration so that it has different moment of inertia at each cross section. In this paper to obtain the influence line of a arbitary-span continuous beam with variable cross sections, the value of some particular function due to a load at any point can be carried out by numerical integration instead of definite integral. The ordinate of the influence line equals the product of the magnitude of the final moment at each support due to unit moment at any support and the load terms due to unit load, measured at the point of application of the load. It is concluded that this method can be easily used to design continuous bridges with arbitary cross sections.