• Title/Summary/Keyword: Circular Plate

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Development of an Optical Waveguide Loss Measuring System using an Rectangular Glass Probe

  • Choi, Young-Kyu
    • Journal of Sensor Science and Technology
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    • v.10 no.1
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    • pp.71-79
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    • 2001
  • The use of a glass-plate probe of rectangular shape is proposed for the measurement of transmission loss in optical waveguides. The light-collecting window is of a thin, rectangular shape and is perpendicular to the light streak, while the conventional fiberglass probe has a small circular face. This transversely elongated form results in a grate improvement of mechanical tolerance for the probe movement in the vortical as well as in the transverse direction. A theoretical investigation also presents a reasonable agreement with the experiments.

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Corrected Solvability Conditions for Nonlinear Asymmetric Vibrations of a Circular Plate -A Report on a Discussion with Nayfeh and Mook- (원판의 비선형 비대칭진동을 위한 가해조건을 수정하고 -Nayfeh, Mook교수와 함께 보낸 한 주일-)

  • 이원경
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.11b
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    • pp.565-575
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    • 2001
  • 나는 대학원생인 여명환군과의 공동연구를 통해 결함 없는(perfect) 원판의 비선형 비대칭진동에 관한 Sridhar, Mook, Nayfeh에 의한 기존연구[1]에서 구한 가해조건(solvability conditions: 해를 asymptotic expansion으로 근사하는 과정에서 해가 유한하기 위해 응답특성이 만족해야 하는 조건)에 오류가 있음을 발견하고 수정하게 되었다. (중략)

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Wideband Rectangular Planar Monopole Antenna for OAM Wave Generation

  • Qasem, Nidal;Alamayreh, Ahmad
    • International Journal of Computer Science & Network Security
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    • v.21 no.3
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    • pp.55-59
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    • 2021
  • Generating electromagnetic waves with Orbital Angular Momentum (OAM) properties is a fast-growing research subject in both radio and optics. This paper describes the generation of OAM carrying waves using a circular array of rectangular planar monopole antennas. The proposed design combines simplicity, compactness, and most importantly very wideband of operating frequencies (about 20-160 GHz, bandwidth ratio about 1:8) which makes it suitable for future applications.

Heat (mass) transfer measurement and analysis with flows around film cooling holes and circular cylinders (막냉각홀 주위와 원형돌출봉 주위에서의 열(물질)전달의 측정과 해석)

  • Kim, B.G.;Wu, S. J.;Cho,H. H.
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.21 no.11
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    • pp.1485-1495
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    • 1997
  • The present study investigates heat/mass transfer around film cooling jets and circular cylinders to compare the characteristics of each other. Experiments are conducted to obtain the detailed heat/mass transfer coefficients of flat plate with injections through an array of holes and for flows around an array of protruding circular cylinders using the naphthalene sublimation technique. The inclination angles of cylinders are set to the same ones of jets; a, the angle between the jet and the surface is fixed at 30 deg. through the whole experiments and .betha., the angle between the projection of the jet on the surface and the direction of main stream is adjusted to 0 deg., 45 deg. and 90 deg. to investigate the effect of variation of injection angles. The influence of blowing rates of jets and those of cylinder length to diameter ratios are also investigated. The results indicate that the increase of angle .betha. influences the spanwise uniformity of heat/mass transfer remarkably for both jets and cylinders, but that variation of cylinder length to diameter ratios has weaker effects on heat/mass transfer coefficients than that of blowing rates.

A study on an efficient prediction of welding deformation for T-joint laser welding of sandwich panel Part II : Proposal of a method to use shell element model

  • Kim, Jae Woong;Jang, Beom Seon;Kang, Sung Wook
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.6 no.2
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    • pp.245-256
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    • 2014
  • I-core sandwich panel that has been used more widely is assembled using high power $CO_2$ laser welding. Kim et al. (2013) proposed a circular cone type heat source model for the T-joint laser welding between face plate and core. It can cover the negative defocus which is commonly adopted in T-joint laser welding to provide deeper penetration. In part I, a volumetric heat source model is proposed and it is verified thorough a comparison of melting zone on the cross section with experiment results. The proposed model can be used for heat transfer analysis and thermal elasto-plastic analysis to predict welding deformation that occurs during laser welding. In terms of computational time, since the thermal elasto-plastic analysis using 3D solid elements is quite time consuming, shell element model with multi-layers have been employed instead. However, the conventional layered approach is not appropriate for the application of heat load at T-Joint. This paper, Part II, suggests a new method to arrange different number of layers for face plate and core in order to impose heat load only to the face plate.

Development of a Novel Noncontact ECG Electrode by MEMS Fabrication Process

  • Mathias, Dakurah Naangmenkpeong;Park, Jaesoon;Kim, Eungbo;Joung, Yeun-Ho
    • Transactions on Electrical and Electronic Materials
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    • v.17 no.3
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    • pp.150-154
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    • 2016
  • Contact electrodes pose threats like inflammation, metal poisoning, and allergic reaction to the user during long term ECG procedure. Therefore, we present a novel noncontact electrocardiographic electrode designed through microelectromechanical systems (MEMS) process. The proposed ECG electrode consists of small inner and large outer circular copper plates separated by thin insulator. The inner plate enables capacitive transduction of bio-potential variations on a subject’s chest into a voltage that can be processed by a signal processing board, whereas the outer plate shields the inner plate from environmental electromagnetic noise. The electrode lead wires are also coaxially designed to prevent cables from coupling to ground or electronic devices. A prototype ECG electrode has an area of about 2.324 cm2, is very flexible and does not require power to operate. The prototype ECG electrode could measure ECG at about 500 um distance from the subject’s chest.

Compressibility behaviour of peat reinforced with precast stabilized peat columns and FEM analysis

  • Kalantari, Behzad;Rezazade, Reza K.
    • Geomechanics and Engineering
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    • v.9 no.4
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    • pp.415-426
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    • 2015
  • Researches have been done to discover ways to strengthen peat soil deposits. In this model study, fibrous peat that is the most compressible types of peat has been reinforced with precast peat columns stabilized with ordinary Portland cement and polypropylene fibres. Rowe cell consolidation tests as well as plate load tests (PLTs) were conducted on various types of test samples to evaluate the strength and deformation of untreated peat and peat reinforced by various types of columns. PLTs were conducted in a specially designed and fabricated circular steel test tank. The compression index ($C_c$) and recompression index ($C_r$) of fibrous peat samples reduced considerably upon use of precast columns. Also, PLT results confirmed the results obtained from Rowe cell tests. Use of polypropylene fibres added to cement further decreased ($C_c$) and ($C_r$) and increased load bearing capacity of untreated peat. Finite element method (FEM) using Plaxis 3D was carried out to evaluate the stress distributions along various types of tested samples and also, to compare the deformations obtained from FEM analysis with the actual maximum deformations found from PLTs. FEM results indicate that most of the induced stresses are taken on the upper portion of tested samples and reach their maximum values below the loading plate. Also, a close agreement was found between actual deformation values obtained from PLTs and values resulted from FEM analysis for various types of tested samples.

Modeling of Low Velocity Impact Damage in Laminated Composites (라미네이트 복합재 판의 저속 충격 손상 모델링)

  • Kong, Chang-Duk;Lee, Joung-Whan;C., Soutis
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2005.04a
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    • pp.240-244
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    • 2005
  • In this study a simple model is developed that predicts impact damage in a composite laminate using an analytical model. The model uses a non-linear approximation method (Rayleigh-Ritz) and the large deflection plate theory to predict the number of failed plies and damage area in a quasi-isotropic composite circular plate (axisymmetric problem) due to a point impact load at its centre. It is assumed that the deformation due to a static transverse load is similar to that occurred in a low velocity impact. It is found that the model, despite its simplicity, is in good agreement with FEM predictions and experimental data for the deflection of the composite plate and gives a good estimate of the number of failed plies due to fibre breakage. The predicted damage zone could be used with a fracture mechanics model developed by the second investigator and co-workers to calculate the compression after impact strength of such laminates. This approach could save significant running time when compared to FEM solutions.

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Hybrid Full-field Stress Analysis around a Circular Hole in a Tensile Loaded Plate using Conformal Mapping and Photoelastic Experiment (등각사상 맵핑 및 광탄성 실험법에 의한 원형구명 주위의 하이브리드 응력장 해석)

  • Baek, Tae-Hyun;Kim, Myung-Soo;Rhee, Ju-Hun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.23 no.6 s.165
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    • pp.988-1000
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    • 1999
  • An experimental study is presented for the effect of number of terms of a pewee series type stress function on stress analysis around a hole in tensile loaded plate. The hybrid method coupling photoelastsic data inputs and complex variable formulations involving conformal mappings and analytical continuity is used to calculate tangential stress on the boundary of the hole in uniaxially loaded, finite width tensile plate. In order to measure isochromatic data accurately, actual photoelastic fringe patterns are two times multiplied and sharpened by digital image processing. For qualitative comparison, actual fringes are compared with calculated ones. For quantitative comparison, percentage errors and standard deviations with respect to percentage errors are caculated for all measured points by changing the number of terms of stress function. The experimental results indicate that stress concentration factors analyzed by the hybrid method are accurate within three percent compared with ones obtained by theoretical and finite element analysis.

Vibration Analysis of Conical Shells with Annular Plates Using Transfer of Influence Coefficient (영향계수의 전달에 의한 환원판이 결합된 원추형 셸의 진동해석)

  • Choi, Myung-Soo;Yeo, Dong-Jun
    • Journal of Power System Engineering
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    • v.19 no.5
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    • pp.52-59
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    • 2015
  • This paper is presented for the free vibration of a conical shell with annular plates or circular plate using the transfer of influence coefficient. The governing equations of vibration of a conical shell, including annular plate, are written as a coupled set of first order differential equations by using the transfer matrix of the shell. Once the transfer matrix of a single component has been determined, the entire structure matrix is obtained by the product of each component matrix and the joining matrix. The natural frequencies and the modes of vibration were calculated numerically for joined conical-annular plates. The validity of the present method is demonstrated through simple numerical examples, and through comparison with the results of finite element method, transfer matrix method and ANSYS. The conclusion show that the present method can accurately obtain natural vibration characteristics of the conical shell with annular or circle end plates.