We employ a simple effective nucleon-nucleon interaction for sd-shell model calculations derived from the Reid soft-core potential folded with two-body correlation functions which take account of the strong short-range repulsion and large tensor component in the Reid force. Shell model calculations for ground and low lying energy states of neutron rich oxygen isotopes 18-28O are performed using OXBASH code. Generally, this interaction predicts correct ordering of levels, yields reasonable energies for ground states of considered isotopes and predicts very well the newly observed excitation energy of
in 26O. Besides, it produces reasonable energy spectra for 23-27O and compressed energy spectra for 18-22O isotopes. This is mainly due entirely to defects in the
diagonal matrix elements of employed interaction. To improve the present calculations, we modify the interaction through replacing the 14 diagonal matrix elements of
with those of the USD interaction. Mostly, our modified interaction predicts well the ordering of levels, the ground state energies and low lying energy spectra for all selected oxygen isotopes. The modified interaction confirms the location of the neutron drip line at
and also identifies the presence of the shell gap at
and
which proves the doubly magic behavior of 22O and 24O. The spins in 24O of several excitation energies around 7.5 MeV are predicted by our interactions. The calculated results obtained with the modified interaction are very close to those obtained with the empirical interactions of USDB and WPN.
Shell model study of neutron rich 18-28O isotopes using effective interactions
energy spectrum
energy levels
binding energy
oxygen isotopes
shell model
Publication Date
Tue Oct 01 2013
Journal Name
Journal Of Economics And Administrative Sciences
أثـر الأدوات الداخلية لحوكمة الشركة على رأس المال الـعـامـل وانعكاسهما علـى القيـمـة الاقتصـادية المضـافـة: دراســة تطبيقيـة علـى عينــة مـــن الشـركــات الصنــاعــيــة المـدرجــة في بورصــة عـمّــان لــلأوراق المـالـيـة
/ Corporate Governance Instrument- Net Working Capital- Economic Value Added- Weighted Average Cost of Capital- Capital Asset Pricing Model
أدوات حوكمة الشركات- صافي راس المال العامل- القيمة الاقتصادية المضافة- المتوسط الموزون لكلفة راس المال- نموذج تسعير الاصول الرأسمالية.
Abstract
Objective of this research focused on testing the impact of internal corporate governance instruments in the management of working capital and the reflection of each of them on the Firm performance. For this purpose, four main hypotheses was formulated, the first, pointed out its results to a significant effect for each of corporate major shareholders ownership and Board of Directors size on the net working capital and their association with a positive relation. The second, explained a significant effect of net working capital on the economic value added, and their link inverse relationship, while the third, explored a significant effect for each of the corporate major shareholders ownershi
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Publication Date
Mon Nov 01 2010
Journal Name
Al-nahrain Journal Of Science
Chemical Elements Diffusion in the Solar Interior
The standard solar model and equation of state have been used to study relative diffusion of Hydrogen and Helium in the present time for solar interior
as a function of distance and depth from the center of the star. The effects of temperature and density on diffusion velocity for these chemical elements have been explaned.
It is found that heat flow which is arising from these reactions leads to an increase in helium diffusion velocity
while the temperature and density leading to a decrease in Hydrogen diffusion velocity. This means that Hydrogen behaves inversely with that for helium does through these reactions. Accordingly
diffusion percentages for Hydrogen
Helium and other Heavy Elements could be determined for the main sequence stars and white dwarf stars.