Results for "A. S. Umar"

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Quadrupole resonances in unstable oxygen isotopes in time-dependent density-matrix formalismJun 28 2002Sep 10 2002The strength functions of quadrupole modes in the unstable oxygen isotopes 22O and 24O are calculated using an extended version of the time-dependent Hartree-Fock theory known as the time-dependent density-matrix theory (TDDM). It is found that TDDM gives ... More
Dipole resonances in oxygen isotopes in time-dependent density-matrix theoryApr 20 2001Jul 18 2001The strength functions of isovector dipole resonances in the even oxygen isotopes $^{18\sim24}$O are calculated by using an extended version of the time-dependent Hartree-Fock theory known as the time-dependent density-matrix theory (TDDM). The results ... More
Formation and dynamics of fission fragmentsDec 17 2013Mar 13 2014Although the overall time-scale for nuclear fission is long, suggesting a slow process, rapid shape evolution occurs in its later stages near scission. Theoretical prediction of the fission fragments and their characteristics are often based on the assumption ... More
Center-of-mass motion and cross-channel coupling in time-dependent Hartree-Fock theoryApr 29 2008Sep 26 2008We provide a discussion of issues related to the center-of-mass motion and cross-channel coupling in applications of the time-dependent Hartree-Fock (TDHF) theory to heavy-ion collisions. We find that the entrance channel dynamics of a heavy-ion collision ... More
3-D unrestricted TDHF fusion calculations using the full Skyrme interactionMar 13 2006We present a study of fusion cross sections using a new generation Time-Dependent Hartree-Fock (TDHF) code which contains no approximations regarding collision geometry and uses the full Skyrme interaction, including all of the time-odd terms. In addition, ... More
Microscopic analysis of sub-barrier fusion enhancement in $^{132}$Sn+$^{40}$Ca vs. $^{132}$Sn+$^{48}$Ca}Jan 23 2013We provide a theoretical analysis of recently measured fusion cross sections which show a surprising enhancement at low $E_\mathrm{c.m.}$ energies for the system $^{132}$Sn+$^{40}$Ca as compared to the more neutron-rich system $^{132}$Sn+$^{48}$Ca. Dynamic ... More
Time-dependent HF approach to SHE dynamicsDec 04 2014We employ the time-dependent Hartree-Fock (TDHF) method to study various aspects of the reactions utilized in searches for superheavy elements. These include capture cross-sections, quasifission, prediction of $P_{\mathrm{CN}}$, and other interesting ... More
Compressibility and equation of state of finite nucleiJun 13 2007We present a new approach for calculating the nuclear equation of state and compressibility for finite nuclei using the density-constrained Hartree-Fock method.
Dynamical deformation effects in subbarrier fusion of $^{64}$Ni+$^{132}$SnSep 25 2006We show that dynamical deformation effects play an important role in fusion reactions involving the $^{64}$Ni nucleus, in particular the $^{64}$Ni+$^{132}$Sn system. We calculate fully microscopic interaction potentials and the corresponding subbarrier ... More
Time-Dependent Response Calculations of Nuclear ResonancesJan 04 2005A new alternate method for evaluating linear response theory is formally developed, and results are presented. This method involves the time-evolution of the system using TDHF and is constructed directly on top of a static Hartree-Fock calculation. By ... More
Dependence of fusion on isospin dynamicsSep 27 2016We introduce a new microscopic approach to calculate the dependence of fusion barriers and cross-sections on isospin dynamics. The method is based on the time-dependent Hartree-Fock theory and the isoscalar and isovector properties of the energy density ... More
Equilibration dynamics and isospin effects in nuclear reactionsApr 12 2019We discuss equilibration times and isospin effect for various quantities in low-energy heavy-ion reactions. These include equilibration of mass, isospin, and total kinetic energy (TKE) in quasifission and deep-inelastic reactions. The calculations are ... More
Deformed shell effects in $^{48}$Ca+$^{249}$Bk quasifission fragmentsJun 18 2019Background: Quasifission is the main reaction channel hindering the formation of superheavy nuclei (SHN). Its understanding will help to optimize entrance channels for SHN studies. Quasifission also provides a probe to understand the influence of shell ... More
Absence of hindrance in microscopic $^{12}$C+$^{12}$C fusion studyJun 05 2019Background: Studies of low-energy fusion of light nuclei are important in astrophysical modeling, with small variations in reaction rates having a large impact on nucleosynthesis yields. Due to the lack of experimental data at astrophysical energies, ... More
Density constrained TDHFFeb 13 2015In this manuscript we provide an outline of the numerical methods used in implementing the density constrained time-dependent Hartree-Fock (DC-TDHF) method and provide a few examples of its application to nuclear fusion. In this approach, dynamic microscopic ... More
$^{64}$Ni+$^{64}$Ni fusion reaction calculated with the density-constrained time-dependent Hartree-Fock formalismSep 25 2007We study fusion reactions of the $^{64}$Ni+$^{64}$Ni system using the density-constrained time-dependent Hartree-Fock (TDHF) formalism. In this formalism the fusion barriers are directly obtained from TDHF dynamics. In addition, we incorporate the entrance ... More
TDHF fusion calculations for spherical+deformed systemsApr 04 2006We outline a formalism to carry out TDHF calculations of fusion cross sections for spherical + deformed nuclei. The procedure incorporates the dynamic alignment of the deformed nucleus into the calculation of the fusion cross section. The alignment results ... More
On the semigroup of order-decreasing partial isometries of a finite chainJan 13 2011Let ${\cal I}_n$ be the symmetric inverse semigroup on $X_n = \{1, 2,..., n\}$ and let ${\cal DDP}_n$ and ${\cal ODDP}_n$ be its subsemigroups of order-decreasing partial isometries and of order-preserving order-decreasing partial isometries of $X_n$, ... More
Density-constrained time-dependent Hartree-Fock calculation of $^{16}$O+$^{208}$Pb fusion cross sectionsFeb 11 2008Nov 10 2008We present a fully microscopic study of the $^{16}$O+$^{208}$Pb fusion using the density-constrained time-dependent Hartree-Fock theory. The calculated fusion cross-sections are in good agreement with the experimental data for the entire energy range ... More
Study of $^{64}$Ni+$^{132}$Sn Fusion with Density Constrained TDHF FormalismMay 09 2007We study fusion reactions of the $^{64}$Ni+$^{132}$Sn system using the recently introduced density constrained time-dependent Hartree-Fock formalism. In this formalism the fusion barriers are directly obtained from TDHF dynamics. In addition, we incorporate ... More
Heavy-ion interaction potential deduced from density-constrained TDHF calculationMay 31 2006We present a new method for calculating the heavy-ion interaction potential from a density-constrained time-dependent Hartree-Fock calculation.
Transport properties of isospin asymmetric nuclear matter using TDHFJun 15 2017Jun 25 2017Background: The study of deep-inelastic reactions of nuclei provide a vehicle to investigate nuclear transport phenomena for a full range of equilibration dynamics. These inquires provide us the ingredients to model such phenomena and help answer important ... More
Quantal diffusion approach for multi-nucleon transfers in Xe + Pb collisionsApr 21 2019Employing a quantal diffusion description based on the stochastic mean-field (SMF) approach, we analyze the mass distribution of the primary fragments in the collisions of ${}^{136} \text{Xe}+{}^{208} \text{Pb}$ system at the bombarding energy $E_\text{c.m.} ... More
Quantal Diffusion Description of Multi-Nucleon Transfers in Heavy-Ion CollisionsFeb 14 2018Employing the stochastic mean-field (SMF) approach, we develop a quantal diffusion description of the multi-nucleon transfer in heavy-ion collisions at finite impact parameters. The quantal transport coefficients are determined by the occupied single-particle ... More
Hartree-Fock-Bogoliubov Calculations in Coordinate Space: Neutron-Rich Sulfur, Zirconium, Cerium, and Samarium IsotopesSep 29 2003Using the Hartree-Fock-Bogoliubov (HFB) mean field theory in coordinate space, we investigate ground state properties of the sulfur isotopes from the line of stability up to the two-neutron dripline ($^{34-52}S$). In particular, we calculate two-neutron ... More
Neutron Transfer Dynamics and Doorway to Fusion in Time-Dependent Hartree-Fock TheoryMay 27 2008Jul 16 2008We analyze the details of mass exchange in the vicinity of the Coulomb barrier for heavy-ion collisions involving neutron-rich nuclei using the time-dependent Hartree-Fock (TDHF) theory. We discuss the time-dependence of transfer and show that the potential ... More
Coordinate Space HFB Calculations for the Zirconium Isotope Chain up to the Two-Neutron DriplineFeb 21 2005We solve the Hartree-Fock-Bogoliubov (HFB) equations for deformed, axially symmetric even-even nuclei in coordinate space on a 2-D lattice utilizing the Basis-Spline expansion method. Results are presented for the neutron-rich zirconium isotopes up to ... More
Quantal Nucleon Diffusion I: Central Collisions of Symmetric NucleiSep 06 2016Quantal diffusion mechanism of nucleon exchange is studied in the central collisions of several symmetric heavy-ion collisions in the framework of the Stochastic Mean-Field (SMF) approach. Since at bombarding energies below the fusion barrier, di-nuclear ... More
Eulerian Rotations of Deformed Nuclei for TDDFT CalculationsApr 03 2009Feb 12 2014We discuss three practical methods for performing Eulerian rotations of Slater determinants in a three-dimensional Cartesian geometry. In addition to the straightforward application of the active form of the quantum mechanical rotation operator, we introduce ... More
Energy dependence of potential barriers and its effect on fusion cross-sectionsJan 28 2014Couplings between relative motion and internal structures are known to affect fusion barriers by dynamically modifying the densities of the colliding nuclei. The effect is expected to be stronger at energies near the barrier top, where changes in density ... More
Nuclear structure near the neutron dripline: lattice HFB calculations with high-energy continuum couplingSep 16 2002We have developed a new Hartree-Fock-Bogoliubov (HFB) code which has been specifically designed to study ground state properties of nuclei near the neutron and proton drip lines. The unique feature of our code is that it takes into account the strong ... More
Superfluid fission dynamics with microscopic approachesJan 19 2016Recent progresses in the description of the latter stage of nuclear fission are reported. Dynamical effects during the descent of the potential towards scission and in the formation of the fission fragments are studied with the time-dependent Hartree-Fock ... More
HFB Calculations Near the Drip LinesOct 24 2001We present the first set of results of solving the Hartree-Fock-Bogoliubov equations, which describe the self-consistent mean field theory with pairing interaction. Calculations for even-even nuclei are carried out on a two-dimensional axially symmetric ... More
Quasifission dynamics in TDHFAug 19 2015For light and medium mass systems the capture cross-section may be considered to be the same as that for complete fusion, whereas for heavy systems leading to superheavy formations the evaporation residue cross-section is dramatically reduced due to the ... More
Skyrme-HFB Calculations in Coordinate Space for the Krypton Isotopes Up to the Two-Neutron DriplineJan 11 2007For axially symmetric even-even nuclei, we solve the Hartree-Fock-Bogoliubov (HFB) equations on a 2-D grid in cylindrical coordinates. The Skyrme SLy4 interaction is used for the mean field and a zero-range interaction for the pairing field. After decoupling ... More
Lattice Paths and Order-preserving Partial TransformationsApr 29 2013Let ${\cal PO}_n$ be the semigroup of all order-preserving partial transformations of a finite chain. It is shown that there exist bijections between the set of certain lattice paths in the Cartesian plane that start at $(0,0)$, end at $(n-1,n-1)$, and ... More
Shape evolution and collective dynamics of quasifission in TDHFJun 23 2015Background: At energies near the Coulomb barrier, capture reactions in heavy-ion collisions result either in fusion or in quasifission. The former produces a compound nucleus in statistical equilibrium, while the second leads to a reseparation of the ... More
Microscopic DC-TDHF study of heavy-ion potentials and fusion cross sectionsAug 01 2012We study heavy-ion fusion reactions at energies near the Coulomb barrier, in particular with neutron-rich radioactive ion beams. Dynamic microscopic calculations are carried out on a three-dimensional lattice using the Density-Constrained Time-Dependent ... More
Microscopic sub-barrier fusion calculations for the neutron star crustMar 26 2012Apr 24 2012Fusion of very neutron rich nuclei may be important to determine the composition and heating of the crust of accreting neutron stars. Fusion cross sections are calculated using time-dependent Hartree-Fock theory coupled with density-constrained Hartree-Fock ... More
Fusion and quasifission dynamics in the reactions $^{48}$Ca+$^{249}$Bk and $^{50}$Ti+$^{249}$Bk using TDHFJun 02 2016Background: Synthesis of superheavy elements (SHE) with fusion-evaporation reactions is strongly hindered by the quasifission (QF) mechanism which prevents the formation of an equilibrated compound nucleus and which depends on the structure of the reactants. ... More
Dynamics of quasifissionJul 30 2015Quasifission is the primary reaction mechanism that limits the formation of superheavy nuclei and consequently an important ingredient for choosing the best target-projectile combinations for the heavy element searches. Quasifission is characterized by ... More
Microscopic study of $^{16}$O+$^{16}$O fusionJun 24 2013Aug 31 2013We perform a study of $^{16}$O+$^{16}$O fusion at above and below the interaction barrier energies using three-dimensional time-dependent Hartree-Fock (TDHF) calculations at above barrier energies and density-constrained TDHF calculations for the entire ... More
Dissipative dynamics in quasi-fissionSep 10 2014Quasi-fission is the primary reaction mechanism that prevents the formation of superheavy elements in heavy-ion fusion experiments. Employing the time-dependent density functional theory approach we study quasi-fission in the systems $^{40,48}$Ca+$^{238}$U. ... More
Microscopic study of Ca$+$Ca fusionFeb 17 2012We investigate the fusion barriers for reactions involving Ca isotopes $\mathrm{^{40}Ca}+\mathrm{^{40}Ca}$, $\mathrm{^{40}Ca}+\mathrm{^{48}Ca}$, and $\mathrm{^{48}Ca}+\mathrm{^{48}Ca}$ using the microscopic time-dependent Hartree-Fock theory coupled with ... More
Two-body dissipation effects on synthesis of superheavy elementsDec 10 2015To investigate the two-body dissipation effects on the synthesis of superheavy elements, we calculate low-energy collisions of the $N=50$ isotones ($^{82}$Ge, $^{84}$Se, $^{86}$Kr and $^{88}$Sr) on $^{208}$Pb using the time-dependent density-matrix theory ... More
HFB theory for nuclei near the drip-lines: continuum couplingMar 15 2001We have developed a new HFB code that specifically addresses nuclear structure physics near the driplines. The HFB equations are solved on a two-dimensional lattice for axially symmetric even-even nuclei using B-Spline techniques. The quasiparticle energy ... More
Axially symmetric Hartree-Fock-Bogoliubov Calculations for Nuclei Near the Drip-LinesMay 15 2002Jan 10 2003Nuclei far from stability are studied by solving the Hartree-Fock-Bogoliubov (HFB) equations, which describe the self-consistent mean field theory with pairing interaction. Calculations for even-even nuclei are carried out on two-dimensional axially symmetric ... More
Combinatorial results for certain semigroups of order-preserving full contraction mappings of a finite chainMar 29 2013Dec 06 2013Let ${\cal T}_n$ be the full symmetric semigroup on $X_n = \{1, 2,..., n\}$ and let ${\cal OCT}_n$ and ${\cal ORCT}_n$ be its subsemigroups of order-preserving and order-preserving or order-reversing full contraction mappings of $X_n$, respectively. In ... More
Quantal description of nucleon exchange in stochastic mean-field approachMar 12 2015Nucleon exchange mechanism is investigated in central collisions of symmetric heavy-ions in the basis of the stochastic mean-field approach. Quantal diffusion coefficients for nucleon exchange are calculated by including non-Markovian effects and shell ... More
The Skyrme Tensor Force in Heavy Ion CollisionsJul 02 2015Background: [elided for arXiv character count] Purpose: With the advancement of computational power it is now possible to undertake TDHF calculations without any symmetry assumptions and incorporate the major strides made by the nuclear structure community ... More
On certain semigroups of full contractions of a finite chainApr 25 2018Let $[n]=\{1,2,\ldots,n\}$ be a finite chain and let $\mathcal{T}_{n}$ be the semigroup of full transformations on $[n]$. Let $\mathcal{CT}_{n}=\{\alpha\in \mathcal{T}_{n}: (for ~all~x,y\in [n])~\left|x\alpha-y\alpha\right|\leq\left|x-y\right|\}$, then ... More
Ontology Based SMS Controller for Smart PhonesSep 04 2015Text analysis includes lexical analysis of the text and has been widely studied and used in diverse applications. In the last decade, researchers have proposed many efficient solutions to analyze / classify large text dataset, however, analysis / classification ... More
Dynamic Microscopic Theory of Fusion Using DC-TDHFAug 08 2012The density-constrained time-dependent Hartree-Fock (DC-TDHF) theory is a fully microscopic approach for calculating heavy-ion interaction potentials and fusion cross sections below and above the fusion barrier. We discuss recent applications of DC-TDHF ... More
Microscopic study of the $^{132,124}$Sn+$^{96}$Zr reactions: dynamic excitation energy, energy-dependent heavy-ion potential, and capture cross sectionJul 27 2010We study reactions between neutron-rich $^{132}$Sn nucleus and $^{96}$Zr within a dynamic microscopic theory at energies in the vicinity of the ion-ion potential barrier peak, and we compare the properties to those of the stable system $^{124}$Sn+$^{96}$Zr. ... More
Microscopic Composition of Ion-Ion Interaction PotentialsOct 08 2011We present a new method to calculate the total ion-ion interaction potential in terms of building blocks which we refer to as "single-particle interaction potentials". This allows also to compose the separate contributions from neutrons and protons to ... More
Microscopic Calculation of Fusion: Light to Heavy SystemsOct 02 2013The density-constrained time-dependent Hartree-Fock (DC-TDHF) theory is a fully microscopic approach for calculating heavy-ion interaction potentials and fusion cross sections below and above the fusion barrier. We discuss recent applications of DC-TDHF ... More
Microscopic Calculation of Heavy-Ion Potentials Based on TDHFJun 17 2011We discuss the implementation and results of a recently developed microscopic method for calculating ion-ion interaction potentials and fusion cross-sections. The method uses the TDHF evolution to obtain the instantaneous many-body collective state using ... More
The TDHF Code Sky3DOct 22 2013The nuclear mean-field model based on Skyrme forces or related density functionals has found wide-spread application to the description of nuclear ground states, collective vibrational excitations, and heavy-ion collisions. The code Sky3D solves the static ... More
Fusion using time-dependent density-constrained DFTFeb 06 2014We present results for calculating fusion cross-sections using a new microscopic approach based on a time-dependent density-constrained DFT calculations. The theory is implemented by using densities and other information obtained from TDDFT time-evolution ... More
Entrance Channel Dynamics of Hot and Cold Fusion Reactions Leading to Superheavy ElementsApr 15 2010We investigate the entrance channel dynamics for the reactions $\mathrm{^{70}Zn}+\mathrm{^{208}Pb}$ and $\mathrm{^{48}Ca}+\mathrm{^{238}U}$ using the fully microscopic time-dependent Hartree-Fock (TDHF) theory coupled with a density constraint. We calculate ... More
On certain semigroups of partial contractions of a finite chainMar 07 2018Let $[n]=\{1,2,\ldots,n\}$ be a finite chain and let $\mathcal{P}_{n}$ be the semigroup of partial transformations on $[n]$. Let $\mathcal{CP}_{n}=\{\alpha\in \mathcal{P}_{n}: (for ~all~x,y\in Dom~\alpha)~|x\alpha-y\alpha|\leq|x-y|\}$ be the subsemigroup ... More
Confronting measured near and sub-barrier fusion cross-sections for 20O+12C with a microscopic methodApr 30 2013Recently measured fusion cross-sections for the neutron-rich system 20O+12C are compared to dynamic, microscopic calculations using time-dependent density functional theory. The calculations are carried out on a three-dimensional lattice and performed ... More
Microscopic Study of the triple-$α$ ReactionMar 24 2010We present a microscopic dynamical study of the reactions involving three $^{4}$He clusters. We show that the much discussed triple-$\alpha$ linear chain configuration of $^{12}$C is formed with a certain lifetime and subsequently decays into a triangular ... More
Swelling of nuclei embedded in neutron-gas and consequences for fusionMay 12 2015Fusion of very neutron rich nuclei may be important to determine the composition and heating of the crust of accreting neutron stars. We present an exploratory study of the effect of the neutron-gas environment on the structure of nuclei and the consequences ... More
Dynamic microscopic study of pre-equilibrium giant resonance excitation and fusion in the reactions $^{132}$Sn+$^{48}$Ca and $^{124}$Sn+$^{40}$CaJan 25 2012We study pre-equilibrium giant dipole resonance excitation and fusion in the neutron-rich system $^{132}$Sn+$^{48}$Ca at energies near the Coulomb barrier, and we compare photon yields and total fusion cross sections to those of the stable system $^{124}$Sn+$^{40}$Ca. ... More
Microscopic Description of Nuclear Fission DynamicsMar 22 2010We discuss possible avenues to study fission dynamics starting from a time-dependent mean-field approach. Previous attempts to study fission dynamics using the time-dependent Hartree-Fock (TDHF) theory are analyzed. We argue that different initial conditions ... More
Localization in light nucleiNov 01 2010Feb 25 2011We investigate the presence of spatial localization in nuclei using a method that maps the nucleon same-spin pair probability and is based on the density-matrix. The method is used to study spatial localization of light nuclei within the Hartree-Fock ... More
Microscopic Calculation of Pre-Compound Excitation Energies for Heavy-Ion CollisionsSep 18 2009We introduce a microscopic approach for calculating the excitation energies of systems formed during heavy-ion collisions. The method is based on time-dependent Hartree-Fock (TDHF) theory and allows the study of the excitation energy as a function of ... More
Multi-Nucleon Transfer in Central Collisions of $^{238}$U + $^{238}$UJun 12 2017Quantal diffusion mechanism of nucleon exchange is studied in the central collisions of $^{238}$U + $^{238}$U in the framework of the stochastic mean-field (SMF) approach. For bombarding energies considered in this work, the di-nuclear structure is maintained ... More
Relativistic Heavy--Ion Collisions in the Dynamical String--Parton ModelSep 04 2000We develop and extend the dynamical string parton model. This model, which is based on the salient features of QCD, uses classical Nambu-Got\=o strings with the endpoints identified as partons, an invariant string breaking model of the hadronization process, ... More
Shape Coexistence Around $^{44}_{16}$S$_{28}$: The Deformed N=28 RegionJun 10 1994Masses, deformations, radii, and single-particle properties of the very neutron-rich Sulfur isotopes are investigated in the framework of the selfconsistent mean-field theory. The stability of the N=28 magic gap around $^{44}$S is discussed.
Mean Field Studies of Exotic Nuclei}Oct 19 1994{Full three dimensional static and dynamic mean field calculations using collocation basis splines with a Skyrme type Hamiltonian are described. This program is developed to address the difficult theoretical challenges offered by exotic nuclei. Ground ... More
How the Pauli exclusion principle affects fusion of atomic nucleiOct 09 2016The Pauli exclusion principle induces a repulsion between composite systems of identical fermions such as colliding atomic nuclei. Our goal is to study how heavy-ion fusion is impacted by this "Pauli repulsion". We propose a new microscopic approach, ... More
Microscopic study of the effect of intrinsic degrees of freedom on fusionApr 11 2014Fusion cross-sections are computed for the $^{40}$Ca$+^{40}$Ca system over a wide energy range with two microscopic approaches where the only phenomenological input is the Skyrme energy density functional. The first method is based on the coupled-channels ... More
Impact-Parameter Dependence of Multiple Lepton-pair Production from Electromagnetic FieldsOct 26 1994In relativistic heavy-ion collisions, the strong Lorentz-contracted electromagnetic fields are capable of producing copious numbers of lepton pairs through the two-photon mechanism. Monte Carlo techniques have been developed that allow the exact calculation ... More
Investigation of Neutrino-Driven Convection and the Core Collapse Supernova Mechanism Using Multigroup Neutrino TransportSep 18 1997We investigate neutrino-driven convection in core collapse supernovae and its ramifications for the explosion mechanism, for a 15 solar mass model. Our two-dimensional simulation begins at 12 ms after bounce and proceeds for 500 ms. We couple two-dimensional ... More
An Investigation of Neutrino-Driven Convection and the Core Collapse Supernova Mechanism Using Multigroup Neutrino TransportDec 10 1996We investigate neutrino-driven convection in core collapse supernovae and its ramifications for the explosion mechanism. We begin with an ``optimistic'' 15 solar mass precollapse model, which is representative of the class of stars with compact iron cores. ... More
Deciphering Core Collapse Supernovae: Is Convection the Key? I. Prompt ConvectionAug 31 1996We couple two-dimensional hydrodynamics to detailed one-dimensional multigroup flux-limited diffusion neutrino transport to investigate prompt convection in core collapse supernovae. Our initial conditions, time-dependent boundary conditions, and neutrino ... More
The Interplay Between Protoneutron Star Convection and Neutrino Transport in Core Collapse SupernovaeSep 18 1997We couple two-dimensional hydrodynamics to realistic one-dimensional multigroup flux-limited diffusion neutrino transport to investigate protoneutron star convection in core collapse supernovae, and more specifically, the interplay between its development ... More
Regularity and Green's relations for the semigroup of partial contractions of a finite chainMar 06 2018Let $[n]=\{1,2,\ldots,n\}$ be a finite chain and let $\mathcal{P}_{n}$ be the semigroup of partial transformations on $[n]$. Let $\mathcal{CP}_{n}=\{\alpha\in \mathcal{P}_{n}: (for~all ~x,y\in Dom~\alpha)~|x\alpha-y\alpha|\leq|x-y|\}$, then $\mathcal{CP}_{n}$ ... More
Single-particle dissipation in TDHF studied from a phase-space perspectiveAug 28 2012We study dissipation and relaxation processes within the time-dependent Hartree-Fock approach using the Wigner distribution function. On the technical side we present a geometrically unrestricted framework which allows us to calculate the full six-dimensional ... More
Static and Dynamic Chain Structures in the Mean-Field TheoryJun 16 2011We give a brief overview of recent work examining the presence of $\alpha$-clusters in light nuclei within the Skyrme-force Hartree-Fock model. Of special significance are investigations into $\alpha$-chain structures in carbon isotopes and $^{16}$O. ... More
Mean-field nuclear structure calculations on a Basis-Spline Galerkin latticeMay 05 1999Our goal is to carry out high-precision nuclear structure calculations in connection with Radioactive Ion Beam Facilities. The main challenge for the theory of drip line nuclei is that the outermost nucleons are weakly bound (implying a large spatial ... More
Sensitivity of the fusion cross section to the density dependence of the symmetry energyMar 04 2016It is the aim of this paper to discuss the impact of nuclear fusion on the EOS. This is a timely subject given the expected availability of increasingly exotic beams at rare isotope facilities\,\cite{balantekin2014}. In practice, we focus on $^{48}$Ca+$^{48}$Ca ... More
Phase space structure and dynamics within the time-dependent Hartree-Fock approachJan 25 2012We study the equilibration and relaxation processes within the time-dependent Hartree-Fock approach using the Wigner distribution function. On the technical side we present a geometrically unrestricted framework which allows us to calculate the full six-dimensional ... More
MCMC methods for inference in a mathematical model of pulmonary circulationJan 23 2018This study performs parameter inference in a partial differential equations system of pulmonary circulation. We use a fluid dynamics network model that takes selected parameter values and mimics the behaviour of the pulmonary haemodynamics under normal ... More
Effect of Pauli repulsion and transfer on fusionMay 31 2017The effect of the Pauli exclusion principle on the nucleus-nucleus bare potential is studied using a new density-constrained extension of the Frozen-Hartree-Fock (DCFHF) technique. The resulting potentials exhibit a repulsion at short distance. The charge ... More
Investigation of HIV-1 Gag binding with RNAs and Lipids using Atomic Force MicroscopyMay 27 2019Atomic Force Microscopy was utilized to study the morphology of Gag, {\Psi}RNA, and their binding complexes with lipids in a solution environment with 0.1{\AA} vertical and 1nm lateral resolution. TARpolyA RNA was used as a RNA control. The lipid used ... More
Sub-barrier enhancement of fusion as compared to a microscopic method in 18O+12CJul 22 2014Measurement of the energy dependence of the fusion cross-sec on at sub-barrier energies provides an important test for theoretical models of fusion. To extend the measurement of fusion cross-sections in the sub-barrier domain for the 18O+12C system. Use ... More
A Systematic and Meta-analysis Survey of Whale Optimization AlgorithmMar 20 2019Whale Optimization Algorithm (WOA) is a nature-inspired meta-heuristic optimization algorithm, which was proposed by Mirjalili and Lewis in 2016. This algorithm has shown its ability to solve many problems. Comprehensive surveys have been conducted about ... More
Interacting entropy-corrected new agegraphic tachyon, K-essence and dilaton scalar field models of dark energy in non-flat universeMar 22 2010Apr 06 2010We present the new agegraphic dark energy model by introducing the quantum corrections to the entropy-area relation in the setup of loop quantum gravity. Employing this new form of dark energy, we investigate the model of interacting dark energy and derive ... More
Hemodynamic assessment of pulmonary hypertension in mice: a model based analysis of the disease mechanismDec 05 2017May 17 2018This study uses a one dimensional fluid dynamics arterial network model to infer changes in hemodynamic quantities associated with pulmonary hypertension in mice. Data for this study include blood flow and pressure measurements from the main pulmonary ... More
Migration from Copper to Fiber Access Network using Passive Optical Network for Green and Dry Field Areas of PakistanSep 20 2015Passive Optical Networks (PON) technology brings an evolution in the industry of Telecommunication for the provisioning of High Speed Internet (HSI) and Triple Play bundled Services that includes Voice, Data, and Video Streaming throughout the world. ... More
Constructing Even Order Magic Squares By Consecutive NumberingMar 19 2013The aim of this note is to introduce fastest new general methods for the construction of double and single even order magic squares. As in [5], the method for double even order magic squares is fairly straight-forward but some adjustments are necessary ... More
Multi-nucleon transfer in ${}^{58}\text{Ni}+{}^{60}\text{Ni}$ and ${}^{60} \text{Ni}+{}^{60}\text{Ni}$ in stochastic mean-field approachJul 24 2018The multi-nucleon exchange mechanism in ${}^{58} \text{Ni}+{}^{60} \text{Ni}$ and ${}^{60} \text{Ni}+{}^{60}\text{Ni}$ collisions is analyzed in the framework of the stochastic mean-field approach. The results of calculations are compared with the TDRPA ... More
Sensitivity analysis and uncertainty quantification of 1D models of the pulmonary circulationJul 08 2018This study combines a one-dimensional (1D) model with micro-CT imaging and hemodynamic data to quantify uncertainty of flow and pressure predictions in the pulmonary arteries in a control and hypoxia induced hypertensive mouse. We use local and global ... More
Prompt muon-induced fission: a sensitive probe for nuclear energy dissipation and fission dynamicsMar 30 2004Following the formation of an excited muonic atom, inner shell transitions may proceed without photon emission by inverse internal conversion, i.e. the muonic excitation energy is transferred to the nucleus. In actinides, the 2p -> 1s and the 3d -> 1s ... More
Interacting entropy-corrected holographic Chaplygin gas modelMar 17 2010Apr 06 2010Holographic dark energy (HDE), presents a dynamical view of dark energy which is consistent with the observational data and has a solid theoretical background. Its definition follows from the entropy-area relation $S(A)$, where $S$ and $A$ are entropy ... More
A Systematic and Meta-analysis Survey of Whale Optimization AlgorithmMar 20 2019Apr 24 2019Whale Optimization Algorithm (WOA) is a nature-inspired meta-heuristic optimization algorithm, which was proposed by Mirjalili and Lewis in 2016. This algorithm has shown its ability to solve many problems. Comprehensive surveys have been conducted about ... More
Level Up Your Strategy: Towards a Descriptive Framework for Meaningful Enterprise GamificationMay 29 2016Gamification initiatives are currently top-of-mind for many organizations seeking to engage their employees in creative ways, improve their productivity, and drive positive behavioural outcomes in their workforce - ultimately leading to positive business ... More