A theoretical investigation of low frequency diameter oscillations of muscular arteries

1994 ◽  
Vol 22 (3) ◽  
pp. 253-263 ◽  
Author(s):  
H. Achakri ◽  
A. Rachev ◽  
N. Stergiopulos ◽  
J. J. Meister
Keyword(s):  
Theoretical Investigation ◽  
Low Frequency

scholarly journals A New Modular Multilevel Inverter Based on Step-Up Switched-Capacitor Modules

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 524 ◽  
Author(s):  
Aryorad Khodaparast ◽  
Erfan Azimi ◽  
Ali Azimi ◽  
M. Ebrahim Adabi ◽  
Jafar Adabi ◽  
...  
Keyword(s):  
Theoretical Investigation ◽  
High Efficiency ◽  
Harmonic Distortion ◽  
Low Frequency ◽  
Multilevel Inverter ◽  
Voltage Source ◽  
Switched Capacitor ◽  
Level Control ◽  
Dc Voltage ◽  
Bipolar Voltage

A new structure of switched capacitor multilevel inverter (SCMLI) capable of voltage boosting and with self-balancing ability is introduced in this article. This advantage is the result of a step by step rise of capacitor voltages in each module, supplied by just one DC voltage source. The proposed topology generates a sinusoidal output waveform with a magnitude several times greater than the input one. Higher output staircase AC voltage is obtained by applying a nearest level control (NLC) modulation technique. The most significant features of this configuration can be mentioned as: fewer semiconductor devices, remarkably low total harmonic distortion (THD), desirable operating under high /low frequency, high efficiency, inherent bipolar voltage production, easy circuit expansion, ease of control and size reduction of the circuit thanks to utilizing neither bulky transformer nor inductor. Moreover, the proposed SCMLI is comprehensively surveyed through theoretical investigation and a comparison of its effectiveness to recent topologies. Eventually, the operating principle of a 25-level prototype of the suggested SCMLI is validated by simulation in the MATLAB SIMULINK environment and experimental results.

scholarly journals Low-frequency vibrations of two-dimensional droplets on heterogeneous substrates

2014 ◽  
Vol 754 ◽  
pp. 515-549 ◽  
Author(s):  
Nikos Savva ◽  
Serafim Kalliadasis
Keyword(s):  
Case Studies ◽  
Theoretical Investigation ◽  
Evolution Equations ◽  
Low Frequency ◽  
Numerical Approach ◽  
Two Dimensional ◽  
Droplet Transport ◽  
Matching Procedure ◽  
Substrate Vibrations ◽  
Unidirectional Motion

AbstractWe present a theoretical investigation of the effects of low-frequency vibrations on the motion of two-dimensional droplets on heterogeneous substrates in the presence of gravity and substrate heterogeneities, both chemical and topographical. A combined analytical and numerical approach is undertaken, extending the work of Savva & Kalliadasis (J. Fluid Mech., vol. 725, 2013, pp. 462–491) on inclined heterogeneous substrates to include the effects of substrate vibrations. Via a matching procedure and under the quasi-static assumption, we obtain evolution equations for the moving fronts. These equations are then invoked in a wide variety of case studies. It is demonstrated that vertically vibrated horizontal ratcheted substrates can induce unidirectional motion. For inclined substrates, we focus on a number of qualitative aspects of the peculiar vibration-induced climbing of droplets reported in experiments by Brunet, Eggers & Deegan (Phys. Rev. Lett., vol. 99, 2007, art. 144501). We examine the effects of weak inertia on the dynamics, deduce analytical criteria for the uphill motion in the limit of weak gravitational and vibrational effects, and demonstrate that substrate heterogeneities may be utilised to enhance droplet transport.

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