scholarly journals Symmetry breaking of azimuthal waves: Slow-flow dynamics on the Bloch sphere

2020 ◽  
Vol 5 (2) ◽  
Author(s):  
Abel Faure-Beaulieu ◽  
Nicolas Noiray
Keyword(s):  
Symmetry Breaking ◽  
Flow Dynamics ◽  
Slow Flow ◽  
Bloch Sphere ◽  
Azimuthal Waves

On the Dynamics of the Polygonal Satellite Vortices

2009 ◽  
Author(s):  
Hamid Ait Abderrahamane ◽  
Kamran Siddiqui ◽  
Georgios Vatistas
Keyword(s):  
Image Analysis ◽  
Symmetry Breaking ◽  
Vortex Core ◽  
Water Layer ◽  
Rotating Disk ◽  
Flow Dynamics ◽  
Cylindrical Container ◽  
Polygonal Pattern ◽  
Hollow Vortex ◽  
The Given

This paper deals with the dynamics of polygonal shapes resulting from the symmetry breaking of hollow-vortex core in a shallow water layer produced by a rotating disk near the bottom within a stationary cylindrical container. These polygonal shapes are investigated through image analysis. It is found that a given polygon rotates at the frequency close to one–third of the corresponding disk frequency and the flow dynamics around the apexes of the polygon is characterized by a frequency which is close to one–third of the frequency of the given polygonal pattern. The results also suggest a possible resonance between the satellite vortices at the apexes of the patterns and the bulk flow.

scholarly journals Peripheral Vascular Anomalies – Essentials in Periinterventional Imaging

2019 ◽  
Vol 192 (02) ◽  
pp. 150-162 ◽  
Author(s):  
Maliha Sadick ◽  
Daniel Overhoff ◽  
Bettina Baessler ◽  
Naema von Spangenberg ◽  
Lena Krebs ◽  
...  
Keyword(s):  
Therapeutic Approach ◽  
Vascular Malformations ◽  
Vascular Anomaly ◽  
Flow Dynamics ◽  
Vascular Anomalies ◽  
Vascular Tumors ◽  
Slow Flow ◽  
Peripheral Vascular ◽  
Fast Flow ◽  
Selection Of

Background Peripheral vascular anomalies represent a rare disease with an underlying congenital mesenchymal and angiogenetic disorder. Vascular anomalies are subdivided into vascular tumors and vascular malformations. Both entities include characteristic features and flow dynamics. Symptoms can occur in infancy and adulthood. Vascular anomalies may be accompanied by characteristic clinical findings which facilitate disease classification. The role of periinterventional imaging is to confirm the clinically suspected diagnosis, taking into account the extent and location of the vascular anomaly for the purpose of treatment planning. Method In accordance with the International Society for the Study of Vascular Anomalies (ISSVA), vascular anomalies are mainly categorized as slow-flow and fast-flow lesions. Based on the diagnosis and flow dynamics of the vascular anomaly, the recommended periinterventional imaging is described, ranging from ultrasonography and plain radiography to dedicated ultrafast CT and MRI protocols, percutaneous phlebography and transcatheter angiography. Each vascular anomaly requires dedicated imaging. Differentiation between slow-flow and fast-flow vascular anomalies facilitates selection of the appropriate imaging modality or a combination of diagnostic tools. Results Slow-flow congenital vascular anomalies mainly include venous and lymphatic or combined malformations. Ultrasound and MRI and especially MR-venography are essential for periinterventional imaging. Arteriovenous malformations are fast-flow vascular anomalies. They should be imaged with dedicated MR protocols, especially when extensive. CT with 4D perfusion imaging as well as time-resolved 3D MR-A allow multiplanar perfusion-based assessment of the multiple arterial inflow and venous drainage vessels of arterio-venous malformations. These imaging tools should be subject to intervention planning, as they can reduce procedure time significantly. Fast-flow vascular tumors like hemangiomas should be worked up with ultrasound, including color-coded duplex sonography, MRI and transcatheter angiography in case of a therapeutic approach. In combined malformation syndromes, radiological imaging has to be adapted according to the dominant underlying vessels and their flow dynamics. Conclusion Guide to evaluation of flow dynamics in peripheral vascular anomalies, involving vascular malformations and vascular tumors with the intention to facilitate selection of periinterventional imaging modalities and diagnostic and therapeutic approach to vascular anomalies. Key Points:  Citation Format

Targeted energy transfer in stochastically excited system with nonlinear energy sink

2018 ◽  
Vol 30 (5) ◽  
pp. 869-886
Author(s):  
P. KUMAR ◽  
S. NARAYANAN ◽  
S. GUPTA
Keyword(s):  
Energy Transfer ◽  
Equations Of Motion ◽  
Nonlinear Energy Sink ◽  
Flow Dynamics ◽  
Slow Flow ◽  
Targeted Energy Transfer ◽  
Optimal Regime ◽  
Excited System ◽  
Energy Sink ◽  
Nonlinear Energy

This study investigates the phenomenon of targeted energy transfer (TET) from a linear oscillator to a nonlinear attachment behaving as a nonlinear energy sink for both transient and stochastic excitations. First, the dynamics of the underlying Hamiltonian system under deterministic transient loading is studied. Assuming that the transient dynamics can be partitioned into slow and fast components, the governing equations of motion corresponding to the slow flow dynamics are derived and the behaviour of the system is analysed. Subsequently, the effect of noise on the slow flow dynamics of the system is investigated. The Itô stochastic differential equations for the noisy system are derived and the corresponding Fokker–Planck equations are numerically solved to gain insights into the behaviour of the system on TET. The effects of the system parameters as well as noise intensity on the optimal regime of TET are studied. The analysis reveals that the interaction of nonlinearities and noise enhances the optimal TET regime as predicted in deterministic analysis.

scholarly journals The Effect of Slow Invariant Manifold and Slow Flow Dynamics on the Energy Transfer and Dissipation of a Singular Damped System with an Essential Nonlinear Attachment

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Jamal-Odysseas Maaita ◽  
Efthymia Meletlidou
Keyword(s):  
Energy Transfer ◽  
Total Energy ◽  
Invariant Manifold ◽  
Nonlinear Oscillator ◽  
Invariant Manifolds ◽  
Dissipative System ◽  
Flow Dynamics ◽  
Slow Flow ◽  
Damped System ◽  
Slow Invariant Manifold

We study the effect of slow flow dynamics and slow invariant manifolds on the energy transfer and dissipation of a dissipative system of two linear oscillators coupled with an essential nonlinear oscillator with a mass much smaller than the masses of the linear oscillators. We calculate the slow flow of the system, the slow invariant manifold, the total energy of the system, and the energy that is stored in the nonlinear oscillator for different sets of the parameters and show that the bifurcations of the SIM and the dynamics of the slow flow play an important role in the energy transfer from the linear to the nonlinear oscillator and the rate of dissipation of the total energy of the initial system.

scholarly journals Pkd2 Affects Cilia Length and Impacts LR Flow Dynamics and Dand5

2021 ◽  
Vol 9 ◽  
Author(s):  
Raquel Jacinto ◽  
Pedro Sampaio ◽  
Mónica Roxo-Rosa ◽  
Sara Pestana ◽  
Susana S. Lopes
Keyword(s):  
Symmetry Breaking ◽  
Cell Shape ◽  
Flow Dynamics ◽  
Cell Stage ◽  
Permeable Channel ◽  
Putative Role ◽  
Breaking Mechanism

The left-right (LR) field recognizes the importance of the mechanism involving the calcium permeable channel Polycystin-2. However, whether the early LR symmetry breaking mechanism is exclusively via Polycystin-2 has not been tested. For that purpose, we need to be able to isolate the effects of decreasing the levels of Pkd2 protein from any eventual effects on flow dynamics. Here we demonstrate that curly-up (cup) homozygous mutants have abnormal flow dynamics. In addition, we performed one cell stage Pkd2 knockdowns and LR organizer specific Pkd2 knockdowns and observed that both techniques resulted in shorter cilia length and abnormal flow dynamics. We conclude that Pkd2 reduction leads to LR defects that cannot be assigned exclusively to its putative role in mediating mechanosensation because indirectly, by modifying cell shape or decreasing cilia length, Pkd2 deficit affects LR flow dynamics.

Probing the evolution of slow flow dynamics in metallic glasses

2016 ◽  
Vol 93 (10) ◽  
Author(s):  
P. Luo ◽  
Z. Lu ◽  
Y. Z. Li ◽  
H. Y. Bai ◽  
P. Wen ◽  
...  
Keyword(s):  
Metallic Glasses ◽  
Flow Dynamics ◽  
Slow Flow

Symmetry breaking in convergent-beam diffraction

1989 ◽  
Vol 47 ◽  
pp. 480-481
Author(s):  
D.J. Eaglesham
Keyword(s):  
Symmetry Breaking ◽  
Point Group ◽  
X Ray Diffraction ◽  
Multiple Diffraction ◽  
Space Groups ◽  
Atomic Displacements ◽  
Small Probe ◽  
Phase Sensitive ◽  
Convergent Beam

Convergent Beam Electron Diffraction is now almost routinely used in the determination of the point- and space-groups of crystalline samples. In addition to its small-probe capability, CBED is also postulated to be more sensitive than X-ray diffraction in determining crystal symmetries. Multiple diffraction is phase-sensitive, so that the distinction between centro- and non-centro-symmetric space groups should be trivial in CBED: in addition, the stronger scattering of electrons may give a general increase in sensitivity to small atomic displacements. However, the sensitivity of CBED symmetry to the crystal point group has rarely been quantified, and CBED is also subject to symmetry-breaking due to local strains and inhomogeneities. The purpose of this paper is to classify the various types of symmetry-breaking, present calculations of the sensitivity, and illustrate symmetry-breaking by surface strains.CBED symmetry determinations usually proceed by determining the diffraction group along various zone axes, and hence finding the point group. The diffraction group can be found using either the intensity distribution in the discs

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