• Title/Summary/Keyword: radial direction

Search Result 743, Processing Time 0.029 seconds

Pressure Effect on Safranine Penetration in Some Hardwood Species

  • Chong, Song-Ho;Ahmed, Sheikh Ali;Park, Byung-Su;Chun, Su-Kyoung
    • Journal of the Korea Furniture Society
    • /
    • v.18 no.2
    • /
    • pp.111-119
    • /
    • 2007
  • An experiment was conducted to know the safranine impregnation distance from surface to inward using 6 different hardwood species. During impregnation, 3 parameters were applied-vacuum, pressure and soaking time. Only vacuum treatment did not increase the permeability of wood. Vacuum followed by pressure increased the penetration depth of safranine in radial, tangential and longitudinal direction. Longitudinal penetration was found easy to impregnate. Comparing with radial and tangential direction, radial penetration was found easy. There was a striking difference among sapwood and heartwood permeability. Safranine input depth was found highest in diffused porous wood rather than in ring porous wood. At increased vacuum and pressure, safranine penetration was found easy.

  • PDF

Numerical study on dynamics of a tornado-like vortex with touching down by using the LES turbulence model

  • Ishihara, Takeshi;Liu, Zhenqing
    • Wind and Structures
    • /
    • v.19 no.1
    • /
    • pp.89-111
    • /
    • 2014
  • The dynamics of a tornado-like vortex with touching down is investigated by using the LES turbulence model. The detailed information of the turbulent flow fields is provided and the force balances in radial and vertical directions are evaluated by using the time-averaged axisymmetric Navier-Stokes equations. The turbulence has slightly influence on the mean flow fields in the radial direction whereas it shows strong impacts in the vertical direction. In addition, the instantaneous flow fields are investigated to clarify and understand the dynamics of the vortex. An organized swirl motion is observed, which is the main source of the turbulence for the radial and tangential components, but not for the vertical component. Power spectrum analysis is conducted to quantify the organized swirl motion of the tornado-like vortex. The gust speeds are also examined and it is found to be very large near the center of vortex.

A TMR Budget Design for 100kTPI Hard Disk Drives Using a Head Gimbal Assembly with Radial Motion Capability (100 kTPI급 HDD TMR 설계를 위한 Suspension에 관한 연구)

  • D. H. Oh;S. W. Kang;Y. S. Han;Kim, Y. H.;T. Y. Hwang
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 2002.11a
    • /
    • pp.320.2-320
    • /
    • 2002
  • In high-capacity disk drives with ever-growing track density, the allowable level of position error signal (PES) is becoming smaller and smaller. A substantial portion of the PES is caused by disk vibration. This can be reduced by using a head gimbal assemblies (HGAs) that do not confine the slider movement to the vertical direction to disks, but allow movement to the radial direction of disks with respect to disk vibration. Several types of HGAs are proposed for such radial motion of the slider. (omitted)

  • PDF

Analysis of belt behavior for a metal V-belt CVT (금속 V-벨트 CVT의 벨트거동 해석)

  • 김현수;이재신
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.15 no.2
    • /
    • pp.557-566
    • /
    • 1991
  • The metal V-belt behavior of a continuously variable transmission was investigated analytically and experimentally. Numerical results showed that nondimensional belt radial displacement increased in the radial inward direction for the driven pulley, while that of the driver pulley increased for the first 90 degrees of the active are and decreased with the increasing torque load. Experimental results for the belt radial displacement were in good agreement with the theoretical results. However, the absolute magnitude of the belt radial displacement was so small that the change in the belt displacement could not be measured in the experimental range except for the inlet region of the driven pulley, where the radial inward displacement was observed due to the effect of bending moment. The speed ratio-axial force relationship derived from the belt behavior analysis also showed god agreement with the experiment.

Analysis of radial error motion in a small-sized and high-speed spindle (소형-고속 스핀들의 반경방향 오차분석 방법)

  • 이응삼;이재하;양승한
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 2004.10a
    • /
    • pp.604-608
    • /
    • 2004
  • In this paper, an efficient method is proposed to analyze the radial error of a miniaturized-high speed spindle system. Initially, a device is constructed for measuring the radial error motion using capacitance sensors. The capacitance sensors are placed perpendicular to the axis of the shaft and at 90o to each other. The spindle is rotated at high speed and the profile of the spindle is recorded. An algorithm is developed for analyzing the spindle data and determining the radial error of spindle. The present algorithm uses homogeneous transform matrix (HTM) method and iterative process for determining the radial error. The analysis procedure is performed for different speeds of the spindle. The data obtained from the present system and the results of evaluation are also presented in this paper. It is observed that this method is effective in determining and analyzing the spindle errors for high speed miniaturized spindle.

  • PDF

Forming Characteristics of Radial Extrusions (레이디얼 압출의 성형특성)

  • Lee Soo-Hyung;Hwang Beong-Bok
    • Proceedings of the Korean Society for Technology of Plasticity Conference
    • /
    • 1999.05a
    • /
    • pp.75-78
    • /
    • 1999
  • This paper is concerned with the family of parts that generally feature a central hub with radial protrusions. Typical parts that fall into this category include cross Pieces for universal joints, tube fittings, and differential gears. As opposed to conventional forward and backward extrusion, in which the material flows in a direction parallel to that of the punch or die motion, the material flows perpendicular to the punch motion in radial extrusion. In this study, the forming characteristics of radial extrusion will be considered by comparing the forces, shapes etc. The design factors during radial extrusion are investigated by the rigid-plastic FEM simulation.

  • PDF

Evaluation of Grinding Characteristics in Radial Direction of Silicon Wafer (실리콘 웨이퍼의 반경 방향에 따른 연삭 특성 평가)

  • Kim, Sang-Chul;Lee, Sang-Jik;Jeong, Hae-Do;Lee, Seok-Woo;Choi, Heon-Jong
    • Proceedings of the KSME Conference
    • /
    • 2003.04a
    • /
    • pp.980-986
    • /
    • 2003
  • As the ultra precision grinding can be applied to wafering process by the refinement of the abrasive, the development of high stiffness equipment and grinding skill, the conventional wafering process which consists of lapping, etching, Ist, 2nd and 3rd polishing could be exchanged to the new process which consists of precision surface grinding, final polishing and post cleaning. Especially, the ultra precision grinding of wafer improves the flatness of wafer and the efficiency of production. Futhermore, it has been not only used in bare wafer grinding, but also applied to wafer back grinding and SOI wafer grinding. This paper focused on the effect of the wheel path density and relative velocity on the characteristic of ground wafer in in-feed grinding with cup-wheel. It seems that the variation of the parameters in radial direction of wafer results in the non-uniform surface quality over the wafer. So, in this paper, the geometric analysis on grinding process is carried out, and then, the effect of the parameters on wafer surface quality is evaluated

  • PDF

Determination of Diffusion Coefficients of Boron from Borate Rods in Wood Using Boltzmann's Transformation

  • Ra, Jong-Bum
    • Journal of the Korean Wood Science and Technology
    • /
    • v.31 no.3
    • /
    • pp.24-29
    • /
    • 2003
  • This research was performed to investigate the diffusivity of borate rods in radiata pine (Pinus radiata D. Don) conditioned to 40 percent moisture content (MC). The deepest penetration of boron were observed in the longitudinal direction, followed by the radial and the tangential directions. The boron loading on the wood face adjacent to the borate rod tended to increase with diffusion time in all directions. To mathematically quantify boron diffusion, the diffusion coefficient of boron was determined using Boltzmann's transformation by assuming that it was a function of concentration only. The values of the longitudinal diffusion coefficients were between 1.3×10-8 cm2/sec and 9.2×10-8 cm2/sec. The radial diffusion coefficients were between 1.4×10-8 cm2/sec and 9.5×10-8 cm2/sec, and the tangential diffusion coefficients were between 5.2×10-9 cm2/sec and 1.3×10-8 cm2/sec. The differences of diffusion coefficients between the longitudinal direction and the radial direction were slight, although their concentration profiles were markedly different. This indicates that the amount of boron loading on the wood face adjacent the borate rod is one of the most important factor for boron penetration in wood with low MC.

RADIAL OSCILLATION OF LINEAR DIFFERENTIAL EQUATION

  • Wu, Zhaojun
    • Bulletin of the Korean Mathematical Society
    • /
    • v.49 no.5
    • /
    • pp.911-921
    • /
    • 2012
  • In this paper, the radial oscillation of the solutions of higher order homogeneous linear differential equation $$f^{(k)}+A_{n-2}(z)f^{(k-2)}+{\cdots}+A_1(z)f^{\prime}+A_0(z)f=0$$ with transcendental entire function coefficients is studied. Results are obtained to extend some results in [Z. Wu and D. Sun, Angular distribution of solutions of higher order linear differential equations, J. Korean Math. Soc. 44 (2007), no. 6, 1329-1338].

ON RADIAL OSCILLATION OF ENTIRE SOLUTIONS TO NONHOMOGENEOUS ALGEBRAIC DIFFERENTIAL EQUATIONS

  • Zhang, Guowei
    • Bulletin of the Korean Mathematical Society
    • /
    • v.55 no.2
    • /
    • pp.545-559
    • /
    • 2018
  • In this paper we mainly investigate the properties of the solutions to a type of nonhomogeneous algebraic differential equation in an angular domain. It includes the Borel directions of the solutions, the width of angular domains in which the solutions take its order and the measure of radial distributions of Julia sets of the solutions.