Semi-classical calculations of the α decay half-lives for even–even nuclei

2019 ◽  
Vol 28 (06) ◽  
pp. 1950042 ◽  
Author(s):  
A. Soylu
Keyword(s):  
Present Model ◽  
Liquid Drop ◽  
Experimental Studies ◽  
Quantization Condition ◽  
Hindrance Factor ◽  
Magic Numbers ◽  
Α Decay ◽  
Dependent Potential ◽  
Experimental Values ◽  
Diffuseness Parameter

The half-lives of the [Formula: see text] decay for even–even nuclei having [Formula: see text] (164 nuclei) have been calculated by using the Wentzel–Kramers–Brillouin (WKB) method together Bohr–Sommerfeld (BS) quantization condition for cosh potential in two-different forms with and without the isospin effects for six different parameter sets. By comparing the obtained results with the experimental values, the rms deviations have been computed. It is obtained that when the cosh potential is used in 2 different type forms, the rms values are also changed and the better one for obtaining the half-lives is cosh-2 form. Even if the isospin-dependent potential does not have so much effect on rms values in this sort of WKB with BS calculations with cosh potential forms, considering the isospin effect together the isospin-dependent nuclear diffuseness parameter have a strong influence on the rms values. New hindrance factor formula based on liquid drop model was used in order to show the influence of hindrance factor on the [Formula: see text] decay half-lives. It is pointed out that this new function of the hindrance factor does not depend on the magic numbers, it contains fewer free parameters and using of this improves the calculations positively. New estimates by using present model have also been made for even–even nuclei having with [Formula: see text] which do not have the measured [Formula: see text] decay half-lives yet and they have been compared the results of the ImSahu model. The present results would provide useful information and knowledge for the explanation of half-lives of [Formula: see text] decay of nuclei and future possible experimental studies.

ALPHA DECAY HALF-LIVES OF EXOTIC NUCLEI AROUND SHELL CLOSURES

2011 ◽  
Vol 20 (01) ◽  
pp. 127-138 ◽  
Author(s):  
Y. Z. WANG ◽  
Q. F. GU ◽  
J. M. DONG ◽  
B. B. PENG
Keyword(s):  
Liquid Drop ◽  
Alpha Decay ◽  
Exotic Nuclei ◽  
Future Research ◽  
Liquid Drop Model ◽  
Α Decay ◽  
Shell Closures ◽  
Experimental Values ◽  
Closed Shells ◽  
Good Agreement

In the framework of the generalized liquid drop model (GLDM) and improved Royer's formula with a set of new coefficients derived by N. D. Schubert et al. [Eur. Phys. J. A42 (2009) 121], the favored and unfavored α-decay half-lives of exotic nuclei around closed shells Z = 82 and N = 126 are investigated. The calculated results are in good agreement with the experimental data. It is shown that our method can be used to study the α-decay half-lives of exotic nuclei around shell closures successfully and is helpful for future research on superheavy nuclei around the next proton and neutron shell closures. In addition, some α-decay half-lives for the cases where the experimental values are unavailable are predicted. We hope our predicted results are useful for future experiments.

Experimental Studies Of Multilayer Glass Structures On Compression, Compression With Bending And Simple Bending

2019 ◽  
pp. 22-30
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Applied Load ◽  
Experimental Studies ◽  
Strength Properties ◽  
Research Topic ◽  
Normative Values ◽  
Laminated Glass ◽  
The Cross ◽  
Experimental Values

The work of multilayer glass structures for central and eccentric compression and bending are considered. The substantiation of the chosen research topic is made. The description and features of laminated glass for the structures investigated, their characteristics are presented. The analysis of the results obtained when testing for compression, compression with bending, simple bending of models of columns, beams, samples of laminated glass was made. Overview of the types and nature of destruction of the models are presented, diagrams of material operation are constructed, average values of the resistance of the cross-sections of samples are obtained, the table of destructive loads is generated. The need for development of a set of rules and guidelines for the design of glass structures, including laminated glass, for bearing elements, as well as standards for testing, rules for assessing the strength, stiffness, crack resistance and methods for determining the strength of control samples is emphasized. It is established that the strength properties of glass depend on the type of applied load and vary widely, and significantly lower than the corresponding normative values of the strength of heat-strengthened glass. The effect of the connecting polymeric material and manufacturing technology of laminated glass on the strength of the structure is also shown. The experimental values of the elastic modulus are different in different directions of the cross section and in the direction perpendicular to the glass layers are two times less than along the glass layers.

THE FISSION BARRIERS OF HEAVY AND EXOTIC NUCLEI

2010 ◽  
Vol 19 (04) ◽  
pp. 514-520 ◽  
Author(s):  
FEDIR IVANYUK ◽  
KRZYSZTOF POMORSKI
Keyword(s):  
Liquid Drop ◽  
Optimal Shape ◽  
Exotic Nuclei ◽  
Fission Barrier ◽  
Heavy Nuclei ◽  
Accurate Approximation ◽  
Barrier Heights ◽  
A Value ◽  
Fission Barriers ◽  
Experimental Values

We have calculated the liquid drop fission barriers of medium and heavy nuclei within the Lublin-Strasbourg-Drop model. Exploiting in addition the topographical theorem by Myers and Światecki we propose a simple but quite accurate approximation of the fission barrier heights. When comparing the r.m.s. deviation of approximated versus experimental values of fission barrier heights for known nuclei with Z > 70 a value 1.1 MeV is obtained which is comparable with the experimental uncertainties. The Strutinsky optimal shape method is generalized to the left-right asymmetric shapes of nuclei in order to investigate the influence of this degree of freedom on the barrier heights.

scholarly journals Structural, elastic, electronic and thermal properties of InAs: A study of functional density

2017 ◽  
Vol 26 (46) ◽  
Author(s):  
Víctor Mendoza-Estrada ◽  
Melissa Romero-Baños ◽  
Viviana Dovale-Farelo ◽  
William López-Pérez ◽  
Álvaro González-García ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Density Functional ◽  
Experimental Studies ◽  
Debye Model ◽  
Band Gap Energy ◽  
Functional Theory ◽  
Zinc Blende ◽  
The Density Functional Theory ◽  
The Stability ◽  
Experimental Values

In this research, first-principles calculations were carried out within the density functional theory (DFT) framework, using LDA and GGA, in order to study the structural, elastic, electronic and thermal properties of InAs in the zinc-blende structure. The results of the structural properties (a, B0, ) agree with the theoretical and experimental results reported by other authors. Additionally, the elastic properties, the elastic constants (C11, C12 and C44), the anisotropy coefficient (A) and the predicted speeds of the sound ( , , and ) are in agreement with the results reported by other authors. In contrast, the shear modulus (G), the Young's modulus (Y) and the Poisson's ratio (v) show some discrepancy with respect to the experimental values, although, the values obtained are reasonable. On the other hand, it is evident the tendency of the LDA and GGA approaches to underestimate the value of the band-gap energy in semiconductors. The thermal properties (V, , θD yCV) of InAs, calculated using the quasi-harmonic Debye model, are slightly sensitive as the temperature increases. According to the stability criteria and the negative value of the enthalpy of formation, InAs is mechanically and thermodynamically stable. Therefore, this work can be used as a future reference for theoretical and experimental studies based on InAs.

Computation of the Surface Materials Modification by Plasma Technology

2020 ◽  
Vol 897 ◽  
pp. 106-110
Author(s):  
Alexey M. Lykov ◽  
Nataliya V. Mokrova
Keyword(s):  
Boundary Conditions ◽  
Surface Treatment ◽  
Experimental Studies ◽  
Design Parameters ◽  
Plasma Technology ◽  
Plasma Surface ◽  
Treatment Processes ◽  
Plasma Surface Treatment ◽  
Experimental Values ◽  
Thermal Influence

Experimental studies of plasma surface treatment processes of various materials are difficult since temperatures of the surface are more than 1500-3000 K, the speed of their change is high (104 K/s), the front of melting is moving. Theoretical researches of the thermal modes are necessary for conducting plasma processes in the best possible way. The use of analytical decisions at impulse thermal influence on the surface allows to calculate temperatures on the surfaces and in the mass of the material under almost any boundary conditions. The paper presents the results of calculation of various plasma processing at dielectric and steel materials (hardening, welding), as well as comparison of the obtained design parameters with experimental values.

The motion of a spherical liquid drop at high Reynolds number

1968 ◽  
Vol 32 (2) ◽  
pp. 367-391 ◽  
Author(s):  
J. F. Harper ◽  
D. W. Moore
Keyword(s):  
Reynolds Number ◽  
Boundary Layers ◽  
Liquid Drop ◽  
Spherical Surface ◽  
Linear Equations ◽  
Steady Motion ◽  
Reynolds Numbers ◽  
Internal Circulation ◽  
High Reynolds ◽  
Experimental Values

The steady motion of a liquid drop in another liquid of comparable density and viscosity is studied theoretically. Both inside and outside the drop, the Reynolds number is taken to be large enough for boundary-layer theory to hold, but small enough for surface tension to keep the drop nearly spherical. Surface-active impurities are assumed absent. We investigate the boundary layers associated with the inviscid first approximation to the flow, which is shown to be Hill's spherical vortex inside, and potential flow outside. The boundary layers are shown to perturb the velocity field only slightly at high Reynolds numbers, and to obey linear equations which are used to find first and second approximations to the drag coefficient and the rate of internal circulation.Drag coefficients calculated from the theory agree quite well with experimental values for liquids which satisfy the conditions of the theory. There appear to be no experimental results available to test our prediction of the internal circulation.

scholarly journals Experimental and Finite Element Studies on Free Vibration of Skew Plates

2014 ◽  
Vol 19 (2) ◽  
pp. 365-377 ◽  
Author(s):  
C.V. Srinivasa ◽  
Y.J. Suresh ◽  
W.P. Prema Kumar
Keyword(s):  
Finite Element ◽  
Aspect Ratio ◽  
Free Vibration ◽  
Composite Laminates ◽  
Natural Frequencies ◽  
Experimental Studies ◽  
Orientation Angle ◽  
Laminated Composite ◽  
Skew Angle ◽  
Experimental Values

Abstract The present paper deals with the experimental studies carried out on free vibration of isotropic and laminated composite skew plates. The natural frequencies were also determined using QUAD8 finite element of MSC/NASTRAN and a comparison was made between the experimental values and the finite element solution. The effects of the skew angle and aspect ratio on the natural frequencies of isotropic skew plates were studied. The effects of the skew angle, aspect ratio, fiber orientation angle and laminate sequence (keeping the number of layers constant) on the natural frequencies of antisymmetric composite laminates were also studied. The experimental values of natural frequencies are in good agreement with the FE solutions. The natural frequencies are found to increase with an increase in the skew angle. The variation of natural frequencies with the aspect ratio is small and negligible both for isotropic and laminated composite skew plates.

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