• Journal of Sensor Science and Technology
• /
• v.6 no.2
• /
• pp.87-94
• /
• 1997

Impedance analysis of a Solenoid sensor to detect the cross-sectional area of non-ferromagnetic stranded conductors is described in this paper. To inspect electromagnetic characteristics of conductive materials, a nondestructive test eddy current sensor with an encircling coil is chosen. As solving Maxwell equation, normalized impedance response of the sensor within a conducting rod is modeled and the results are expanded to the stranded wires. Geometrical property affecting on stranded structure is considered and a numerical and experimental study is also presented.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2003.10a
• /
• pp.29-36
• /
• 2003

This paper deals with the free vibration analysis of horizontally circular mea beams with variable cross sectional width on elastic foundations. Taking into account the effects of rotatory inertia and shear deformation differential equations governing the free vibrations of such beams are derived, in which the Whlkler foundation model is considered as the elastic foundation. The variable width of beam is chosen as the linear equation. The differential equations are solved numerically to calculate natural frequencies. In numerical examples, the curved beam with the hinged-hinged, hinged-clamped, clamped-hinged and damped-clamped end constraints are considered The parametric studies are conducted and the lowest four frequency parameters are reported in figures as the non-dimensional forms.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.4 no.1
• /
• pp.46-52
• /
• 2000

A computational analysis has been made on fluid flow in a regenerative cooling Passage for a reduced size liquid rocket engine to predict pressure drop and heat transfer rate in it. The contraction/expansion of the cross sectional area of the passage turn out to increases both the pressure loss and the heat transfer rate of the duct. The changes of the cross sectional area near the nozzle throat are effective to protect the throat which suffers from severe thermal load. Also given is the qualitative characteristics of the performance of the regenerative cooling system due to the variation of coolant flow rate.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.8 no.4
• /
• pp.545-552
• /
• 2020

This study evaluated the support performance of fiber-net integrated shotcrete in tunnel support system developed for the purpose of improving constructability and stability while fully performing its mechanical performance as a tunnel support materials by four-point bending test, two-dimensional numerical analysis, and cross-sectional analysis. As a result of evaluating the flexural performance through a four-point bending test, in the case of fiber-net reinforced shotcrete, the tensile performance of fiber-net resulted in a continuous increase in load after crack occurrence, unlike steel fiber reinforced shotcrete. Also, the results of the tunnel cross-sectional structure analysis for ground conditions and the cross-sectional analysis of fiber-net and steel fiber reinforced shotcrete showed that sufficient support performance can be exhibited even if the thickness of fiber-net reinforced shotcrete was reduced compared to the previous one. Additionally, through these results, the support pattern of fiber-net integrated shotcrete in tunnel support system, which can be applied efficiently to the construction sections requiring higher stability among the rock mass class III, was proposed.

• Journal of ILASS-Korea
• /
• v.14 no.2
• /
• pp.59-64
• /
• 2009

These experiments are close examination of spray characteristics that are continuous liquid jet and modulated liquid jet. The experiments were conducted using water, over a range of crossflow velocities from $42{\sim}l36\;m/s$, with modulation frequencies of $35.7{\sim}166.2\;Hz$. Between continuous crossflow jet and modulated cross-flow jet of penetration, breakup point, spray angle and macro spray shape are experimentally investigated with image analysis. In cross-flow field, main parameter of liquid jet for breakup was cross-flow stream rather than modulation effect. As oscillation of the periodic pressure that could make liquid jet moved up and down, the mixing efficiency was increased. Also, a bulk of liquid jet puff was detected at upper field of liquid surface. So, this phenomenon has a good advantage of mixing spray from concentration of center area to outer area. Because of modulation frequency, SMD inclination of the structured layer was evanescent. Cross-sectional characteristics of SMD at downstream area were non-structured distributions. Then cross-sectional characteristics of SMD size were about same tendency over a range that is effect of spray mixing. The tendency of volume flux value for various modulation frequency was same distribution. And volume flux was decreased when the modulation frequency increase.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2000.09a
• /
• pp.9-16
• /
• 2000

Applicability of the cross shaped drain in a soft clay ground is examined using the laboratory discharge capacity test, column consolidation test and 3-D numerical flow analysis. The equivalent diameter of the tested drains is back-calculated from the laboratory experiment and compared with those calculated from the formula suggested in the literature. The effective range of the cross shaped drain about the discharge capacity and coefficient of permeability is analyzed. The results of numerical analysis show that the cross shaped drain which has a cross-sectional area twice of the band shaped drain can reduce the consolidation time by 30% from that for the band shaped drain in a soft clay ground that K is over 1${\times}$10$\^$-7/cm/sec

• The Journal of Fisheries Business Administration
• /
• v.28 no.2
• /
• pp.1-18
• /
• 1997

The purpose of this study is to investigate empirically the characteristics of financial structure by using 76 fisheries corporations in Korea, and to suggest implications of the empirical results for government's financial policy for fisheries corporations. For the empirical test, we choose the following factors as the explanatory variables of cross-sectional regression analysis:firm-size(SIZE), collateral value of assets(TFATA), business risk(BRISK), growth(GROWTH), effective tax(ET), profitability(PROFIT). Two different debt ratios are used as dependent variables. One is defined as the ratio of total debt to total assets and the other is as that of long-term debt to total asset in terms of book value. The sample consists of 76 fisheries firms and sample period is 14 years from 1982 till 1995. From the results of cross-sectional regression analysis, the adjusted R$^2$values were high, 16∼79% and the overall F values indicated to be statistically significant. The results of cross sectional regression analysis show that the characteristics of financial structure fur fisheries corporations are as follows ; (1) Firm-size and collateral value of assets are the major factors of financial structure for fisheries corporations. That is, the larger firm-size the higher is debt ratio. This means that financial institutions conventionally lend more collateral loans with fixed assets like land, building rather than management capacities or credits. (2) To be consistent with a pecking-order theory, the higher is profitability the lower is debt ratio in fisheries corporations. (3) Corporations with high effective tax rate have lower financial leverage. Although the empirical results are inconsistent with traditional static trade-off theory, we think it would be attributed to government's various tax shelterings for fisheries which are likely to reduce tax shield effect of interests.

• The korean journal of orthodontics
• /
• v.47 no.6
• /
• pp.353-364
• /
• 2017

Objective: The objective of this study was to investigate the effects of miniscrew-assisted rapid palatal expansion (MARPE) on changes in airflow in the upper airway (UA) of an adult patient with obstructive sleep apnea syndrome (OSAS) using computational fluid-structure interaction analysis. Methods: Three-dimensional UA models fabricated from cone beam computed tomography images obtained before (T0) and after (T1) MARPE in an adult patient with OSAS were used for computational fluid dynamics with fluid-structure interaction analysis. Seven and nine cross-sectional planes (interplane distance of 10 mm) in the nasal cavity (NC) and pharynx, respectively, were set along UA. Changes in the cross-sectional area and changes in airflow velocity and pressure, node displacement, and total resistance at maximum inspiration (MI), rest, and maximum expiration (ME) were investigated at each plane after MARPE. Results: The cross-sectional areas at most planes in NC and the upper half of the pharynx were significantly increased at T1. Moreover, airflow velocity decreased in the anterior NC at MI and ME and in the nasopharynx and oropharynx at MI. The decrease in velocity was greater in NC than in the pharynx. The airflow pressure in the anterior NC and entire pharynx exhibited a decrease at T1. The amount of node displacement in NC and the pharynx was insignificant at both T0 and T1. Absolute values for the total resistance at MI, rest, and ME were lower at T1 than at T0. Conclusions: MARPE improves airflow and decreases resistance in UA; therefore, it may be an effective treatment modality for adult patients with moderate OSAS.

• Women's Health Nursing
• /
• v.20 no.4
• /
• pp.287-296
• /
• 2014

Purpose: The purpose of this study was to analyze the quality of reports on observational studies published in the Korean Journal of Women Health Nursing (KJWHN). Methods: Forty-six studies using cross-sectional designs published in KJWHN from January 2011 to June 2013 were selected for analysis. Selected articles were reviewed and evaluated by three reviewers using the 22 items of the Strengthening the Reporting of Observational studies in Epidemiology (STROBE) statement. As some of 22 items had more than one check point, further broken down, 34 checklist items were used for analysis. Results: Overall, the reviewed studies provided sufficient descriptions for many STROBE items. Seven of the 34 items were found to be not applicable, and 15 of the remaining 27 items (55.5%) were evaluated as 'sufficient' in reporting. Only one study included a flow diagram illustrating participation and this lack of flow diagram was the weakest area of reporting in this review. Conclusion: Clearer reporting of cross-sectional studies can be attained by attention to vulnerable areas of reporting, such as including a flow diagram of participants, descriptions of sources of bias and reason for non-participation, and describing limitations of the study. Issues regarding the application of STROBE statement items should be actively discussed in order to aid future revision and clarification of items included in STROBE statement.

• Journal of Biomedical Engineering Research
• /
• v.22 no.6
• /
• pp.551-557
• /
• 2001

Occlusion of the dural-sac in the lumbar spine was quantitatively analysed using a one motion segment finite element mode developed in this study. Occlusion was quantified by calculating the cross sectional area chance of the dural-sac. In static analysis. less than 2 kN of compressive load could Produced no dural-sac occlusion. whereas 6kN load reduced cross sectional area by 4%, and produced 7.4%, 10.5% occlusion for additional 8 Nm. 10 Nm extension moments. respectively. In creep analysis, 10 Nm extension reduced cross sectional area and volume of the dural-sac by 6.9% and 2.4%, respectively. However. flexion moment could not produce any occlusion. The results suggested that occlusions may result mainly from slackening of ligamentum flavum and disc budging.