scholarly journals Additional Rigidly Rotating Solutions in the String Model of Hadrons

1984 ◽  
Vol 37 (1) ◽  
pp. 1 ◽  
Author(s):  
CJ Burden ◽  
LJ Tassie

Solutions to the relativistic string equation are found which correspond to rigid body rotation about the z-axis with azimuthal velocity greater than the velocity of light. If the solutions lie entirely in the x-y plane they are rotating epicycloids, complimentary to the hypocycloid solutions found previously. The use of a general solution to the string equation in terms of two arbitrary world-lines with null tangents provides an alternative derivation of the rigidly rotating solutions.

1982 ◽  
Vol 35 (3) ◽  
pp. 223 ◽  
Author(s):  
CJ Burden ◽  
LJ Tassie

The relativistic string equation is solved for motion corresponding to rigid body rotation about the z-axis. One class of these solutions, namely the planar solutions, allows for the construction of two types of exotic meson and one type of glueball, all of which have asymptotically straight ChewFrautschi plots. The first type of meson only exists when the number of quarks or antiquarks is 4, 5, 6 or 7, whereas no such restriction applies to the second type. For each of these cases the first type of meson is energetically more favourable than the second type for a given angular momentum.


2011 ◽  
Vol 24 (5) ◽  
pp. 548-555 ◽  
Author(s):  
Bas M. van Dalen ◽  
Kadir Caliskan ◽  
Osama I.I. Soliman ◽  
Floris Kauer ◽  
Heleen B. van der Zwaan ◽  
...  

Author(s):  
S Choura

The reduction of residual vibrations for the position control of a flexible rotating beam carrying a payload mass is investigated. The common practice used to find the position control of a flexible multi-link arm is to assign a torque actuator to each joint while the payload mass is kept fixed relative to the end-link during the time of manoeuvre. This paper examines the stability of the system if either the payload is freed accidentally to move along the beam during the time of manoeuvre or is allowed to span the beam in a desired path for control purposes. A candidate Lyapunov function is constructed and its time rate of change is examined. It is shown that the use of a PD (proportional plus derivative) torque control yields a convergence of residual vibration to zero, an attainment of the rigid-body rotation to a prespecified desired angle of manoeuvre and a constant velocity of the payload mass as it moves relative to the beam. For manipulation purposes, an additional control force is added to the moving actuator in order to regulate its axial motion. It is shown that allowing the axial motion of the payload mass in a prescribed manner leads to a considerable reduction of its residual vibrations as compared to the case where the payload mass is fixed to the beam tip during the time of manoeuvre. Stability is also verified through simulations of rigid-body rotation and payload axial motion track prespecified reference trajectories.


2013 ◽  
Vol 20 (7) ◽  
pp. 073502 ◽  
Author(s):  
A. Fruchtman ◽  
R. Gueroult ◽  
N. J. Fisch

2012 ◽  
Vol 712 ◽  
pp. 3-6 ◽  
Author(s):  
Peter W. Duck

AbstractRotating, stratified flows are important in a wide variety of both geophysical and engineering applications. Whilst ‘steady state’ flows of this type are generally very simple (in effect, rigid body rotation), the effect of abruptly altering (even a little) the rotation rate can induce significant temporal flow disruptions, made all the more complicated when the fluid is bounded inside a closed finite container, a problem studied both experimentally and theoretically by Foster & Munro (J. Fluid Mech., this issue, vol. 712, 2012, pp. 7–40).


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