Dynamic rotational characteristics of actinides on empirical approach

Open Physics ◽  
2008 ◽  
Vol 6 (3) ◽  
Author(s):  
Maria Kaczmarczyk ◽  
Andrzej Korejwo

AbstractIn the paper calculation of the moments of inertia for nuclei from the region 87 ≤ Z ≤ 100 and 130 ≤ N ≤ 156 was made in dependence on the angular momentum of their rotational states. The experimental values of the moments of inertia were calculated for rotational energy of the classic rotor in its quantum form, with the use of a simple formula. The moment of inertia term appearing in the formula was treated as a variable. The calculations were carried out on the basis of experimental data for the energies of the rotational levels for 51 bands built on ground states for even-even nuclei and for nuclei with odd mass number A. In addition, 30 rotational bands built on excited states were also analysed in the investigated region in case of even-even nuclei. For many bands and nuclei the considered dependence of the moment of inertia on angular momentum has been found in the analytical form by fitting polynomials to the experimental data. It turned out that obtained results for the moments of inertia made it possible to describe the energies of rotational levels with a relative deviation not greater or only slightly greater than 1%. In general, in the case of 12 bands of ground level the maximum relative deviation of obtained level energies is smaller than 1%.

1993 ◽  
Vol 21 (4) ◽  
pp. 355-366 ◽  
Author(s):  
David L. Wallach

The moment of inertia of a plane lamina about any axis not in this plane can be easily calculated if the moments of inertia about two mutually perpendicular axes in the plane are known. Then one can conclude that the moments of inertia of regular polygons and polyhedra have symmetry about a line or point, respectively, about their centres of mass. Furthermore, the moment of inertia about the apex of a right pyramid with a regular polygon base is dependent only on the angle the axis makes with the altitude. From this last statement, the calculation of the centre of mass moments of inertia of polyhedra becomes very easy.


2004 ◽  
Vol 190 ◽  
pp. 176-177
Author(s):  
Y. Lipkin ◽  
E. M. Leibowitz

AbstractThe classical nova V4633 Sgr (1998) exhibits two photometric periodicities. The shorter period (P1=3.01 hr) is stable, while the other one, longer by ~2.5%, has decreased monotonically since shortly after the nova eruption, with Ṗ2 ≈ –10−6 (Lipkin et al. 2001).Here we report on results of photometric monitoring of the star in 2001 and 2002. During our observations, the longer period decreased more, and in 2002 it was only 1.8% longer than P1 The decrease rate (Ṗ2) in 2001-2002 was an order of magnitude smaller than in 1998-2000.These new results support the Near-Synchronous Polar classification which was suggested for V4633 Sgr (Lipkin et al. 2001). In this model, the longer period of V4633 Sgr is the spin of the white dwarf, and its variation since 1998 reflects changes in the moment of inertia of the white dwarf, and angular momentum transfer in the system following the nova eruption.


1987 ◽  
Vol 115 ◽  
pp. 384-384
Author(s):  
S. Hinata

There is a simple relationship among moment of inertia I, rotational kinetic energy K, and momentum L given by (David Layzer, private communication), 2IK ≧ L. During the Hayashi phase a rotating protostar will amplify the trapped magnetic field by a dynamo-like process. Since the rotation is expected to be fast, many unstable modes will be excited and will grow exponentially in time until some nonlinear processes saturate the amplitude. However, it may happen that the reduction in rotational kinetic energy becomes so large that without increasing the moment of inertia the inequality given above may not be satisfied. The only way to increase the moment of inertia is to move the mass outward. This can be done by transferring the angular momentum outward through the magnetic field. So we will have a fast rotating mass shell at the outer edge of the star. Further transfer of angular momentum will push the shell against the accretion disk; the moving masses of the disk will divert the mass flow along the background magnetic field which extends perpendicular to the accretion disk. This results in the hollow cone jets from both poles because the outward motion is primarily on the equatorial plane.


2017 ◽  
Vol 865 ◽  
pp. 188-191
Author(s):  
Kirill Nezdanov ◽  
Igor Garkin ◽  
Nikolay Laskov

This article is devoted to extreme increase in the moments of inertia of crane rails torsional strongly influence the endurance of crane girders. We investigate increase in moment of inertia of the rail under torsion with increasing thickness of the walls and shelves of thick-walled I-section profile in the square until its transformation into a square profile. It was found that the transformation of the profile of a monolithic solid square increases the moment of inertia of the torsion Jkr, cm4 to 3,1075 times and reaches its extreme. A cross-sectional area remains constant (const). Crane rails with a high moment of inertia for torsion provides significant economic benefits, and significantly reduces the operating costs of the enterprise.


1992 ◽  
Vol 47 (9) ◽  
pp. 971-973 ◽  
Author(s):  
A. Kawski ◽  
P. Bojarski ◽  
A. Kubicki

Abstract The influence of the moment of inertia on the rotational fluorescence depolarization is discussed. Based on experimental results obtained for five luminescent compounds: 2,5-diphenyloxazole (PPO), 2,2'-p-phenylene-bis(5-phenyloxazole) (POPOP), p-bis[2-(5-α-naphthyloxazolyl)]-benzene (α-NOPON), 4-dimethylamino-ω-methylsulphonyl-trans-styrene (3a) in n-parafines at low viscosity (from 0.22 x 10-3 Pa • s to 0.993 x 10-3 Pa • s) and diphenylenestilbene (DPS) in different solvents, a semi-empirical equation is proposed, yielding moments of inertia that are only two to five times higher than those estimated from the molecular geometry


2008 ◽  
Vol 17 (04) ◽  
pp. 655-667 ◽  
Author(s):  
D. MOKHTARI ◽  
I. AMI ◽  
M. FELLAH ◽  
N. H. ALLAL

The neutron-proton (n-p) isovector pairing effect on the nuclear moment of inertia has been studied within the framework of the BCS approximation. An analytical expression of the moment of inertia, that explicitly depends upon the n-p pairing, has been established using the Inglis cranking model. The model was first tested numerically for nuclei such as N = Z and whose experimental values of the moment of inertia are known (i.e. such as 16 ≤ Z ≤ 40). It has been shown that the n-p pairing effect is non-negligible and clearly improves the theoretical predictions when compared to those of the pairing between like particles. Secondly, predictions have been established for even-even proton-rich rare-earth nuclei. It has been shown that the n-p pairing effect is non-negligible when N = Z and rapidly decreases with increasing values of (N-Z).


2013 ◽  
Vol 465-466 ◽  
pp. 368-372
Author(s):  
M. Haniff Junos ◽  
Nurulasikin Mohd Suhadis ◽  
Mahmud M. Zihad

This paper presents the experimental determination of the moment of inertia of USM e-UAV by using pendulum method. Compound pendulum experiment is used to determine the moment of inertia about x and y axes while the moment of inertia about z-axis is determined using bifilar torsion pendulum method. An experimental setup is developed with appropriate dimension to accommodate USM e-UAV. Experimental data are presented and discussed.


1988 ◽  
Vol 15 (2) ◽  
pp. 232-239 ◽  
Author(s):  
Baidar Bakht ◽  
Leslie G. Jaeger

In many slab-on-girder bridges, especially those that are continuous over two or more spans, the moment of inertia of a girder varies significantly along the length of the bridge. This paper critically examines the practice of analyzing such bridges for load distribution by methods that make the assumption of constant longitudinal torsional and flexural rigidities. It is found that this practice may not be valid for those slab-on-girder bridges in which variations of the girder moments of inertia are very large.A recommended procedure is given for cases in which the variation in moment of inertia is not too severe. The procedure involves (a) the determination of total bending moments, treating the bridge as a beam of variable moment of inertia, and (b) the determination of an equivalent constant moment of inertia for beams of varying moment of inertia. Using this procedure the load distribution properties of the bridge can be realistically analyzed by those computer-based methods (e.g., orthotropic plate, finite strip, and semicontinuum methods) or manual methods (e.g., AASHTO and Ontario methods) that cannot directly take account of the variation of longitudinal flexural rigidity.The validity of the recommended procedure is established by comparing its results with those of the grillage analysis method that does take account of the variation of the girder moment of inertia. Key words: bridge analysis, girders, load distribution, slab-on-girder bridges.


1990 ◽  
Vol 05 (29) ◽  
pp. 2403-2406 ◽  
Author(s):  
ALPANA GOEL ◽  
A. K. JAIN

The variable moment of inertia model is extended to rotational bands in odd-odd rare-earth nuclei. Results are presented for the K> = (Ωp + Ωn) bands which remain reasonably free from Coriolis mixing effects. The moment of inertia parameter exhibits significant variation with angular momentum which is strikingly similar to one of the odd-A rotational bands based on either the neutron or the proton configuration also involved in the odd-odd rotational band.


1960 ◽  
Vol 15 (5-6) ◽  
pp. 371-377
Author(s):  
Gerhart Lüders

It has been stated by BOHR and MOTTELSON that INGLIS’ method for the theoretical determination of moments of inertia of deformed nuclei, in the limit of a great number of non-interacting particles leads to the moment of inertia of rigid rotation. Recently doubts have been raised regarding the general validity of this statement. In the present paper the proof of the assertion is given in detail and its relation to the BOHR-VAN-LEEUWEN theorem is discussed.


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