• Title/Summary/Keyword: Tail Model

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Comparison of hemostatic efficacy and cytotoxicity of three ferric subsulfate- and chitosan-based styptics in different formulations using a rat tail bleeding model

  • Byun, Jae-Young;Lee, Soojung;Lee, Jeong Ik;Yoon, Hun-Young
    • Korean Journal of Veterinary Research
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    • v.58 no.3
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    • pp.119-124
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    • 2018
  • This study was conducted to compare the hemostatic efficacy of three ferric subsulfate- and chitosan-based styptics as a powder and a gel containing ferric subsulfate and chitosan (FSC-PO and FSC-G, respectively) and a soaked pad containing ferric subsulfate and lidocaine (FSL-SP) using a rat tail bleeding model. The cytotoxicity of the styptics against L-929 mouse fibroblasts was also evaluated using a cell counting kit-8 assay. Four groups of 10 rats each were assigned to the three different styptics and a non-treated control groups. Rat tail tips were transected, after which styptics were applied with pressure. The wounds were observed for hemostasis for 3 min, then irrigated with saline to check for recurrent hemorrhage. L-929 mouse fibroblasts were exposed to extracts of the styptics (100 mg/mL) and their dilutions (1:10, 1:100, and 1:1,000). FSC-PO and FSC-G more effectively controlled initial hemorrhage than FSL-SP (p = 0.033). Additionally, FSC-PO and FSC-G more effectively maintained hemostasis than the control group (p = 0.02 and p < 0.01, respectively). However, all styptics showed enhanced cytotoxicity against L-929 cells in a dose-dependent manner. Therefore, although FSC-PO and FSC-G would be recommended to control hemorrhage, the benefits of styptics must be balanced against the clinical significance of their cytotoxicity.

Flutter Safety Analysis of a Composite Smart UAV with T-tail Configuration (T-형 꼬리날개를 갖는 복합재 스마트 무인기의 플러터 안전성 해석)

  • Kim, D.H.;Yang, Y.J.;Jung, S.U.;Kim, S.J.;Choi, S.C.;Kim, S.C.;Shin, J.W.
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.13 no.1
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    • pp.20-31
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    • 2005
  • In this study, subsonic flutter analyses have been conducted for a composite smart UAV with T-tail configuration at the critical flight condition. Detailed three-dimensional finite element model for dynamic analysis is constructed including its nonstructural elements corresponding to installed electronic equipments and fuels. Computational structural dynamics and aeroelastic techniques are conducted using MSC/NASTRAN and originally developed in-house codes. The results for fundamental vibration characteristics and flutter instabilities are presented and compared to each other for different fuel conditions.

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Antioxidant Effects of Berchemia berchemiaefolia in Nerve Pain Models

  • Lee, Gil-Hyun;Hyun, Kyung-Yae;Choi, Seok-Cheol
    • Biomedical Science Letters
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    • v.23 no.4
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    • pp.380-387
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    • 2017
  • Berchemia berchemiaefolia (BB) are climbing plants or small to medium-sized trees that live in Africa, Asia and America. We performed the present study to investigate whether oral administration of Berchemia berchemiaefolia extract (BBE) protects SD rats from pain. The SD rat experimental groups were divided into four groups. Two of the animal model groups were fed on BBE (200 mg/kg or 100 mg/kg). We performed oral acute toxicity test to determine the optimal oral dose of BBE. To explore if BBE alleviated pain in the SD rat, we undertook the tail flick latency test and formalin test. Additionally, we conducted the anti-oxidative test. The findings of the present study suggest that Berchemia berchemiaefolia extract exhibits strong antioxidant and analgesic activities.

The Study on Impurity Concentration Optimizing for the Refresh Time Improvement of DRAM (DRAM의 Refresh 시간 개선을 위한 불순물 농도 최적화에 관한 연구)

  • Lee Yong-Hui;Woo Kyong-Hwan;Yi Cheon Hee
    • Proceedings of the IEEK Conference
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    • 2000.11b
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    • pp.325-328
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    • 2000
  • The control of the data retention time is a main issue for realizing future high density dynamic random access memory. In this paper, we propose the new implantation scheme by gate-related ion beam shadowing effect and buffer-enhanced $\Delta$ Rp increase using buffered N- implantation with tilt and 4X-rotation that is designed on the basis of the local-field-enhancement model of the tail component. We report an excellent tail improvement of the retention time distribution attributed to the reduction of electric field across the cell junction due to the redistribution of N- concentration which is intentionally caused by Ion Beam Shadowing and Buffering Effect using tilt implantation with 4X-rotation.

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Aerodynamic Performance Analysis of a Shrouded Rotor Using an Unstructured Mesh Flow Solver

  • Lee H. D.;Kwon O. J.;Joo J.
    • 한국전산유체공학회:학술대회논문집
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    • 2003.10a
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    • pp.263-265
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    • 2003
  • The aerodynamic performance of a shrouded tail rotor in hover has been studied by using a compressible inviscid flow solver on unstructured meshes. The numerical method is based on a cell­centered finite-volume discretization and an implicit Gauss-Seidel time integration. The results show that the performance of an isolated rotor without shroud compares well with experiment. In the case of a shrouded rotor, correction of the collective pitch angle is made such that the overall performance matches with experiment to account for the uncertainties of the experimental model configuration. Details of the flow field compare well with the experiment confirming the validity of the present method.

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Computational Investigation of Similarity Law and Wind Tunnel Testing for Side Jet Influence on Supersonic Missile Aerodynamics (초음속 유도탄의 측추력기 작동시 풍동실험을 위한 CFD 해석 연구)

  • Hong S. K.;Sung W. J.
    • Proceedings of the KSME Conference
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    • 2002.08a
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    • pp.87-90
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    • 2002
  • Computational study has been undertaken to investigate the aerodynamic influence of side jet on a supersonic missile and to find a similarity condition between the flight condition and the wind tunnel testing. Tasks were performed to validate the existing Raytheon test body with side jet, to simulate the flow inside the supersonic wind tunnel, and to compare the flow fields between the missile in free flight and that in the wind tunnel. Then sub-scale model of body-tail configuration was analyzed to estimate the influence of the side jet on the missile components. It Is found that the influence of side Jet is not as significant on the tail region as on the body surface and a simple algebraic formula for aerodynamic coefficients accounting for the side jet as a point force may be cautiously utilized in setting up control logic.

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Numerical Comparisons for the Null Distribution of the Bagai Statistic

  • Ha, Hyung-Tae
    • Communications for Statistical Applications and Methods
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    • v.19 no.2
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    • pp.267-276
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    • 2012
  • Bagai et al. (1989) proposed a distribution-free test for stochastic ordering in the competing risk model, and recently Murakami (2009) utilized a standard saddlepoint approximation to provide tail probabilities for the Bagai statistic under finite sample sizes. In the present paper, we consider the Gaussian-polynomial approximation proposed in Ha and Provost (2007) and compare it to the saddlepoint approximation in terms of approximating the percentiles of the Bagai statistic. We make numerical comparisons of these approximations for moderate sample sizes as was done in Murakami (2009). From the numerical results, it was observed that the Gaussianpolynomial approximation provides comparable or greater accuracy in the tail probabilities than the saddlepoint approximation. Unlike saddlepoint approximation, the Gaussian-polynomial approximation provides a simple explicit representation of the approximated density function. We also discuss the details of computations.

Subsonic Flutter Characteristics of a Sandwich Structure Wing with Honeycomb core (하니콤 코어 샌드위치 구조 날개의 아음속 플러터 특성)

  • Kim, Yu-Sung;Kim, Dong-Hyun
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.14 no.2
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    • pp.17-26
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    • 2006
  • The flutter characteristics of all movable tail wing with honeycomb sandwich structure have been studied in this study. The present wing model has a airfoil cross section and the linear variation of spanwise thickness. Structural vibration analysis is performed based on the finite element method using sandwich and beam elements. Unsteady aerodynamic technique used on the doublet lattice method has been effectively used to conduct the frequency-domain flutter analyses. The parametric flutter studies have been performed for various structural design parameters. Computational results on flutter stability due to the variation of structural parameters are presented and its related characteristics are investigated through the comparison of results.

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A Linear Theory of MHD Stability in the Geomagnetotail

  • Lee, Dae-Young
    • International Union of Geodesy and Geophysics Korean Journal of Geophysical Research
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    • v.24 no.1
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    • pp.11-18
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    • 1996
  • A stability analysis in the geomagentotail is presented within MHD limit with a modified form ideal Ohm's law. Using the high ky approximation (ballooning limit), we derive the basic eigenmode equations which can be reduced to the ideal MHD limit. The incompressible limit is numerically solved for a number of model equilibria of tail by Kan [1973], and we have found no unstable Kan equilibrium. Also, an analytic theory is carried out for the case where Bkc is assumed to be constant along the field line, following the idea by Lee and Min [1996]. In that case, it is suggested that the tail stability to the incompressible antisymmetric mode is determined by the ideal MHD.

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Computational Investigation of Similarity Law and Wind Tunnel Testing for Side Jet Influence on Supersonic Missile Aerodynamics (초음속 유도탄의 측추력기 작동시 풍동실험을 위한 CFD 해석 연구)

  • Hong S. K.;Sung W. J.
    • 한국전산유체공학회:학술대회논문집
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    • 2002.05a
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    • pp.41-46
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    • 2002
  • Computational study has been undertaken to investigate the aerodynamic influence of side jet on a supersonic missile and to find a similarity condition between the flight condition and the wind tunnel testing. Tasks were peformed to validate the existing Raytheon test body with side jet, to simulate the flow inside the supersonic wind tunnel, and to compare the flow fields between the missile in free flight and that in the wind tunnel. Then sub-scale model of body-tail configuration was analyzed to estimate the influence of the side jet on the missile components. It is found that the influence of side jet is not as significant on the tail region as on the body surface and a simple algebraic formula for aerodynamic coefficients accounting for the side jet as a point force may be cautiously utilized in setting up control logic.

  • PDF