Effective one-dimensional equation of motion for nuclear fission

1997 ◽  
Vol 36 (8) ◽  
pp. 1907-1919
Author(s):  
M. W. Morsy ◽  
Fathia A. E. A. Imam
1975 ◽  
Vol 97 (1) ◽  
pp. 92-95 ◽  
Author(s):  
E. L. Yellin ◽  
C. S. Peskin

The pressure-flow relations of large amplitude pulsatile water flows across an orifice have been investigated theoretically and experimentally. By retaining the unsteady term in the one-dimensional equation of motion, and by allowing the jet area to be a function of distance in the continuity equation, a lumped parameter relationship between pressure drop and flow has been developed which reflects the influence of inertia and dissipation. The results are applicable to the analysis of natural and prosthetic heart valves under normal and pathologic conditions. Within the physiologically possible conditions of frequency and flow rate, unsteady separated flows exhibit the same energy losses as comparable steady separated flows. Thus, the flow is quasi-steady, even when the waveforms and temporal relations indicate a significant inertial influence.


1994 ◽  
Vol 262 ◽  
pp. 205-221 ◽  
Author(s):  
Jens Eggers ◽  
Todd F. Dupont

We consider the viscous motion of a thin axisymmetric column of fluid with a free surface. A one-dimensional equation of motion for the velocity and the radius is derived from the Navier–Strokes equation. We compare our results with recent experiments on the breakup of a liquid jet and on the bifurcation of a drop suspended from an orifice. The equations form singularities as the fluid neck is pinching off. The nature of the singularities is investigated in detail.


2021 ◽  
pp. 108128652110238
Author(s):  
Barış Erbaş ◽  
Julius Kaplunov ◽  
Isaac Elishakoff

A two-dimensional mixed problem for a thin elastic strip resting on a Winkler foundation is considered within the framework of plane stress setup. The relative stiffness of the foundation is supposed to be small to ensure low-frequency vibrations. Asymptotic analysis at a higher order results in a one-dimensional equation of bending motion refining numerous ad hoc developments starting from Timoshenko-type beam equations. Two-term expansions through the foundation stiffness are presented for phase and group velocities, as well as for the critical velocity of a moving load. In addition, the formula for the longitudinal displacements of the beam due to its transverse compression is derived.


1996 ◽  
Vol 11 (11) ◽  
pp. 899-913 ◽  
Author(s):  
N. FLEURY ◽  
M. RAUSCH DE TRAUBENBERG

A group theory justification of one-dimensional fractional supersymmetry is proposed using an analog of a coset space, just like the one introduced in 1-D supersymmetry. This theory is then gauged to obtain a local fractional supersymmetry, i.e. a fractional supergravity which is then quantized à la Dirac to obtain an equation of motion for a particle which is in a representation of the braid group and should describe alternative statistics. A formulation invariant under general reparametrization is given by means of a curved fractional superline.


2011 ◽  
Vol 207 (1-3) ◽  
pp. 461-464 ◽  
Author(s):  
M. Jalaal ◽  
H. Bararnia ◽  
G. Domairry

1996 ◽  
Vol 118 (1) ◽  
pp. 46-52 ◽  
Author(s):  
A. N. Williams

The hydrodynamic properties of a flexible floating breakwater consisting of a membrane structure attached to a small float restrained by moorings are investigated theoretically. The tension in the membrane is achieved by hanging a clump weight from its lower end. The fluid motion is idealized as linearized, two-dimensional potential flow and the equation of motion of the breakwater is taken to be that of a one-dimensional membrane of uniform mass per unit length subjected to a constant axial force. The boundary integral equation method is applied to the fluid domain, and the dynamic behavior of the breakwater is also described through an appropriate Green function. Numerical results are presented which illustrate the effects of the various wave and structural parameters on the efficiency of the breakwater as a barrier to wave action. It is found that the wave reflection properties of the structure depend strongly on the membrane length, the magnitude of the clump weight, and the mooring line stiffness, while the membrane weight and excess buoyancy of the system are of lesser importance.


2019 ◽  
Vol 21 (02) ◽  
pp. 1850006 ◽  
Author(s):  
Alberto Boscaggin ◽  
Maurizio Garrione

By using a shooting technique, we prove that the quasilinear boundary value problem [Formula: see text] where [Formula: see text] is a ball and [Formula: see text], has more and more pairs of nodal solutions on growing of the parameter [Formula: see text]. The radial Neumann problem and the periodic problem for the corresponding one-dimensional equation are considered, as well.


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