Single mode analysis appears to overestimate the attenuation of human calcaneal bone based on Bayesian-derived fast and slow wave mode analysis

2012 ◽  
Author(s):  
Amber M. Nelson ◽  
Joseph J. Hoffman ◽  
Mark R. Holland ◽  
James G. Miller
Keyword(s):  
Slow Wave ◽  
Single Mode ◽  
Wave Mode ◽  
Mode Analysis

Vibration of Nonuniform Beams Under Moving Point Loads: An Approximate Analytical Solution in Time Domain

2017 ◽  
Vol 17 (03) ◽  
pp. 1750035 ◽  
Author(s):  
C. P. Sudheesh Kumar ◽  
C. Sujatha ◽  
K. Shankar
Keyword(s):  
Approximate Analytical Solution ◽  
Time Integration ◽  
Single Mode ◽  
Mode Analysis ◽  
Moving Loads ◽  
The Finite Element Method ◽  
Require Time ◽  
Analytical Formulae ◽  
Clamped Beams ◽  
Forced Responses

The forced-free responses of nonuniform beams under moving point loads are analyzed in this paper. Simple approximate analytical formulae for the forced responses of undamped nonuniform beams, derived using the fundamental mode by the Rayleigh–Ritz (R–R) method, are presented. The responses of both simply supported and clamped–clamped beams are analyzed. The responses are also determined by the finite element method (FEM) in which nonuniform elements are used for fast convergence. It is found that the present method yields results that are very close to those obtained by the FEM. As this method does not require time integration, it is faster and computationally more efficient. Though the single-mode analysis of forced vibration of uniform beams under moving loads has been done by several researchers, its application to nonuniform beams has not been reported.

Slow-Wave Mode Rectification on Non-Linear Microstrip

1997 ◽  
Vol 32 (4) ◽  
pp. 223-232
Author(s):  
L. E. Winkelmann ◽  
T. K. Ishii
Keyword(s):  
Slow Wave ◽  
Wave Mode ◽  
Non Linear

scholarly journals Single-mode analysis of Yb-doped double-cladding distributed spectral filtering photonic crystal fibers

2010 ◽  
Vol 18 (26) ◽  
pp. 27197 ◽  
Author(s):  
Enrico Coscelli ◽  
Federica Poli ◽  
Thomas T. Alkeskjold ◽  
Davide Passaro ◽  
Annamaria Cucinotta ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
Photonic Crystal Fibers ◽  
Single Mode ◽  
Mode Analysis ◽  
Spectral Filtering ◽  
Crystal Fibers

Expanded-core channel waveguides: Single-mode analysis and application

2008 ◽  
Vol 281 (15-16) ◽  
pp. 3980-3984
Author(s):  
Yeng-Cheng Hu ◽  
Likarn Wang
Keyword(s):  
Single Mode ◽  
Mode Analysis ◽  
Channel Waveguides

scholarly journals Passively Q-Switched and Mode-Locked Er3+-Doped Ring Fiber Laser with Pulse Width of Hundreds of Picoseconds

Photonics ◽  
2021 ◽  
Vol 8 (12) ◽  
pp. 560
Author(s):  
Ji Wang ◽  
Wenwu Zhang ◽  
Tianrun Zhang
Keyword(s):  
Fiber Laser ◽  
Continuous Wave ◽  
Average Power ◽  
Basic Research ◽  
Single Mode ◽  
Frequency Stability ◽  
Wave Mode ◽  
Switching Frequency ◽  
Maximum Output ◽  
Power Instability

Greatly improving the energy of a single mode-locked pulse while ensuring the acquisition of the width of short pulses will contribute to the application of mode-locked pulse in basic research, such as precision machining. This report has investigated a Q-switched and mode-locked (QML) erbium doped ring fiber laser based on the nonlinear polarization rotation (NPR) technology and a mechanical Q-switched device. Without the working of the mechanical Q-switched device, the fiber laser exported the continuous-wave mode-locked (CWML) pulse, with a width of 212.5 ps, and a repetition frequency of 81.97 MHz. For the CWML operation, the maximum output average power is 25.7 mW, and the energy is only 0.31 nJ. For the QML operation, 18.03 mW average power is achieved at the Q-switching frequency of 100 Hz. The energy of the QML pulse is increased by over 1100 times to 360.6 nJ. The width of the QML pulse is 203.1 ps measured by an autocorrelation curve, with the time-band product (TBP) being 0.598. The power instability is 0.5% (RMS) and 0.7% (RMS), respectively, for CWML and QML operation within 120 min. Furthermore, the spectral signal-to-noise ratio is about 60 dB. For the QML operation, the power instability is 0.48% (RMS) within 60 s and 0.37% (RMS) within 10 s. After frequency stabilization, the frequency fluctuation is ±100 Hz in the long-term of 1200 s, with the frequency stability (FS) calculated to be 2.44 × 10−6. It indicates that the QML fiber laser has good power stability and frequency stability.

scholarly journals Simplified VIV Response of Partially Strake-Covered Pipe Spans

2021 ◽  
Author(s):  
Ralf Peek ◽  
Decao Yin ◽  
Jie Wu ◽  
Malcolm Carr ◽  
Sze Yu Ang ◽  
...  
Keyword(s):  
Response Function ◽  
Single Mode ◽  
Added Mass ◽  
Mode Analysis ◽  
Frequency Domain Method ◽  
Assessment Practice ◽  
Damping Parameter ◽  
Wave Effects ◽  
Mass Functions ◽  
Forward Extension

A simplified method for the fatigue assessment for partially strake-covered pipeline spans is provided and calibrated so that for the bare pipe case it is consistent with the current DNVGL Recommended Practice (DNVGL-RP-F105). It is based on a Rayleigh-Ritz approximation using the first undamped mode shape. In that sense it is equivalent to a single-mode analysis using Shear7, except that it accounts for frequency-dependent added mass, and the formulation is presented in a compact and convenient non-dimensional form. The method presented may also be considered a simplification of that in Vivana in that it does not account for propagating wave effects, and is therefore named “Sivana”.Like any frequency-domain method Sivana is based on the assumption of harmonic response. This requires excitation and added mass functions that define a harmonic hydrodynamic force as a function of the harmonic motion. On the other hand, current practice by DNVGL-RP-F105 is based on a response function, which gives VIV amplitude as function of reduced velocity and the Scruton mass-damping parameter Ks. To bridge this gap, an inversion technique is developed whereby the excitation function for bare pipe is derived from the DNVGL-RP-F105 response function, such that for bare pipe the Sivana calculation will lead to the same response amplitudes as DNVGL-RP-F105. The Sivana method is illustrated by an example involving a single span with different degrees of strake coverage centered at midspan.Although the Sivana method might be considered a natural and straight-forward extension of current span assessment practice to include partial strake coverage, caution is in order for certain approximations in the DNVGL-RP-F105 response function may be less appropriate for the use in this paper, than for the use envisioned by the developers of the DNVGL guidance.

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