Papers by Abdalla Obeidat
Effect of crystal field on the magnetic and thermodynamic properties of the Ising mixed spin (1-1/2-1) three layers system of cubic structure
Physica B: Condensed Matter, 2022
Ab initio calculations of structural, optical and magnetic properties of ordered MxPt1-x, (M= Co, Ni, Fe and Mn) binary alloys
Bulletin of the American Physical Society, 2019
Fractional calculus is used to introduce intermediate potential wells between the attractive Dira... more Fractional calculus is used to introduce intermediate potential wells between the attractive Dirac delta function and the negative potential step. Schrodinger equation is solved numerically to obtain solutions for bound states and scattering states. The ground states and their eigen energies evolve until they coincide with bound state for the Dirac delta potential as the intermediate potential evolves into the Dirac delta function potential. For scattering states, the transmission coefficients were obtained and shown to agree with the value of the potential step and then increases to one as the intermediate potential takes the shape of the Dirac delta potential. The disagreement between the transmission coefficients for Dirac delta function and the corresponding intermediate potential was explained by examining the continuity of the derivative of the wave function across the intermediate potentials.
The magnetic properties and phase diagrams of the mixed spin Ising model, with spins S = 1 and σ ... more The magnetic properties and phase diagrams of the mixed spin Ising model, with spins S = 1 and σ = 1 2 on a centered rectangular structure, have been investigated using Monte Carlo simulations based on the Metropolis algorithm. Every spin at one lattice site has four nearestneighbor spins of the same type and four of the other type. We have assumed ferromagnetic interaction between the same spins type, antiferromagnetic for different spin types. An additional single-site crystal field term on the S = 1 site was considered. We have shown that the crystal field enhances the existence of the compensation behavior of the system. In addition, the effects of the crystal field and exchange coupling on the magnetic properties and phase diagrams of the system have been studied. Finally, the magnetic hysteresis cycles of the system for several values of the crystal field have been found.
Physica A: Statistical Mechanics and its Applications, 2021
Monte Carlo simulation has been employed to investigate the magnetic properties and phase diagram... more Monte Carlo simulation has been employed to investigate the magnetic properties and phase diagrams of ferrimagnetic mixed-spin (½, 1) triangular Ising nanotube with core-shell structure. In particular, the effect of the exchange couplings and the temperature on the magnetic and thermodynamic properties, hysteresis loops as well as the compensation temperature have been discussed in detail. Moreover, the effects of the single-ion anisotropy, as well as external magnetic field, have been examined. The threshold values of the exchange couplings and single-ion anisotropy have been found, determining whether the system exhibits a compensation temperature. We have found that the appearance of the compensation temperature is strongly linked with the system parameters. Moreover, we have obtained the double and triple hysteresis loops for certain physical parameters in the considered magnetic system.
AIP Advances, 2018
Thermodynamic, dynamical, and structural properties of ethanol are numerically studied using two ... more Thermodynamic, dynamical, and structural properties of ethanol are numerically studied using two ethanol models: TraPPE-UA and OPLS-AA. These properties are computed with temperatures ranging from 200K to 300K, with steps of 10K, and also with different mole fractions of ethanol at 300K. The TraPPE-UA and OPLS-AA models are mixed with two water models: SPCE and TIP4P. These models have been previously shown to be the best models of methanol among nine different models. In our previous paper on methanol-water mixtures, the OPLS-AA model showed superiority over the TraPPE-UA model in predicting most properties. In this study, we show that the TraPPE-UA has better predictions in all computed properties when compared to the experimental results, except for the total structure factor of mixing with respect to the second maximum.
Computational Investigation of the Electrolyte Properties of Li12P3N9 and Its High Pressure Polymorph Li4PN3 through First-Principles Simulations
Journal of The Electrochemical Society, 2020
Physica A: Statistical Mechanics and its Applications, 2020
This paper presents a novel approach to building an interval dynamic model for an industrial plan... more This paper presents a novel approach to building an interval dynamic model for an industrial plant with uncertainty by an interval neural network (INN). A new type of randomized learner model, named interval random vector functional-link network (IRVFLN), is proposed to take advantages of the inherent RVFLN in rapid modeling. The IRVFLN model is equipped with interval hidden input weights (and biases), which are randomly assigned from certain distribution/range and remain fixed, and the interval output weights can be evaluated by solving a couple of least squares problems. The comparative numerical experiments have verified the good potential of the proposed IRVFLN with the interval learner models produced by the error back-propagation algorithm. In the following modeling application, some measures for building IRVFLN with unknown but bounded (UBB) errors requirements are discussed in depth, in order to modeling an uncertain dynamic plant with IRVFLN by bounded-error data in either known or unknown error bounds. Finally, as a case study, the IRVFLN is applied to modeling a chemical interval dynamic plant with recycling, where the simulation results and generalization ability analysis demonstrate that the proposed method is suitable and effective. INDEX TERMS Interval neural network (INN), random vector functional-link network (RVFLN), unknown but bounded (UBB) errors, uncertain dynamic system modeling.
Journal of Molecular Liquids, 2019
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Dynamics of Duffing-Holmes oscillator with fractional order nonlinearity
The European Physical Journal B, 2019
In this work, the dynamics of Duffing-Holmes oscillator with fractional order nonlinearity is exp... more In this work, the dynamics of Duffing-Holmes oscillator with fractional order nonlinearity is explored. Basically, a fractional spatial derivative is introduced to the cubic term, and the order of the derivative α is varied between zero and two. The evolution of the dynamics of the system from nonlinear behavior to linear behavior is investigated using multiple tools such as phase portraits, Poincare maps, and bifurcation diagrams. We have demonstrated that as α increases the system can alternate between chaotic and periodic states depending on the parameters setting. However, the overall impact transforms the system into simpler dynamics and eventually causes the chaotic regions to fade out regardless of the system settings. The largest α at which the system still exhibits chaotic behavior is estimated to be around 1.17 and for transient chaos is estimated to be 1.25.Graphical abstract
Journal of Superconductivity and Novel Magnetism, 2019
The XY model has been used in a centered rectangular lattice structure consists of two sub-lattic... more The XY model has been used in a centered rectangular lattice structure consists of two sub-lattices of spin 1-1/2 with different ferromagnetic couplings on each lattice and anti-ferromagnetic interaction between the two sub-lattices. Utilizing the Monte Carlo simulation, we have studied the energy per site, the specific heat, the total magnetization, the initial susceptibility, and hysteresis effects. Our results revealed that existences of two peaks on the specific heat and a single loop historic behavior. The Binder cumulant and initial susceptibility both confirmed the existence of critical temperature where the system possesses a phase transition to paramagnetism. Such behaviors are monitoring by the different coupling constants adopted in this study.
Magnetic Properties and Critical and Compensation Temperatures in Mixed Spin-1/2-Spin-1 Ferrimagnetic-Centered Rectangular Structure Using Monte Carlo Simulation
IEEE Transactions on Magnetics, 2019
The Monte Carlo simulation has been used to investigate the magnetic properties of a mixed spin-1... more The Monte Carlo simulation has been used to investigate the magnetic properties of a mixed spin-1 (sublattice A) and spin-1/2 (sublattice B), where each sublattice has a rectangular structure and the whole lattice system forms a 2-D centered rectangular lattice. Five possible interactions are considered. Namely, two S–S interactions and two <inline-formula> <tex-math notation="LaTeX">$\sigma $ </tex-math></inline-formula>–<inline-formula> <tex-math notation="LaTeX">$\sigma $ </tex-math></inline-formula> interactions depend on crystal direction, and an antiferromagnetic interaction between the two sublattices is taken. Our results show that the critical temperature increases with increasing the variation of any exchange interactions. The existence of the compensation temperature depends on the balance between the S–S interactions along <xref ref-type="bibr" rid="ref10">[10]</xref> and <inline-formula> <tex-math notation="LaTeX">$\sigma $ </tex-math></inline-formula>–<inline-formula> <tex-math notation="LaTeX">$\sigma $ </tex-math></inline-formula> interactions along [01] directions.
Heliyon, 2019
In the present work, we applied scaled model to calculate surface tension, vapor densities and th... more In the present work, we applied scaled model to calculate surface tension, vapor densities and the critical temperatures of four different models of methanol: namely, H1, J1, J2 and L1 models. The scaled model is based on calculating the free energy of the system. Free energy calculations were performed by applying the Bennet acceptance ratio (BAR) using Monte-Carlo simulations at low temperature range of 220K-280K. The BAR is based on calculating the free energy difference of n-molecules and (n-1)-molecules plus a free probe on methanol. Estimations of vapor densities are based on extrapolating the intercept of the scaled free energy linear line as number of molecules approaches infinity, which requires a pre-known values for liquid densities. To accomplish this, a series of molecular dynamic simulations were performed at low temperature range of 200K-300K with steps of 10K. All the estimated properties were in excellent agreement with experimental published data.
Physica A: Statistical Mechanics and its Applications, 2018
Childhood developmental disorders cause significant negative impact on the physical, intellectual... more Childhood developmental disorders cause significant negative impact on the physical, intellectual and social-emotional development of an individual. Developmental disorders are common in pediatric practice and these children are more likely to have comorbid behavioral disorders than their typically developing counterparts. They are also at greater risk for academic stress due to scholastic backwardness. Intellectual developmental disorders, communication disorders, autism spectrum disorder and specific learning disorder are the common developmental disorders seen in children. The key interventions for the management of developmental disorders in children are parent training interventions. Early parent training interventions are essential for the reduction in the global prevalence and burden of childhood developmental disorders.
Applied Mathematical Sciences, 2017
The Adomian decomposition method has been widely used to solve ordinary and partial differential ... more The Adomian decomposition method has been widely used to solve ordinary and partial differential equations. The inhomogeneous term or the source term has been expanded in terms of orthogonal polynomials. In this work we expand the source term in terms of Legendre polynomials, Chebyshev polynomials and Taylor expansion. Our results show that the absolute error is the least when using Taylor expansion.
The Journal of chemical physics, Jan 14, 2014
We study the internal structure of nanometer-sized D2O-nonane aerosol droplets formed in superson... more We study the internal structure of nanometer-sized D2O-nonane aerosol droplets formed in supersonic nozzle expansions using a variety of experimental techniques including small angle X-ray scattering (SAXS). By fitting the SAXS spectra to a wide range of droplet structure models, we find that the experimental results are inconsistent with mixed droplets that form aqueous core-organic shell structures, but are quite consistent with spherically asymmetric lens-on-sphere structures. The structure that agrees best with the SAXS data and Fourier transform infra-red spectroscopy measurements is that of a nonane lens on a sphere of D2O with a contact angle in the range of 40°-120°.
Clustered Diagonally Explicit Runge-Kutta Method for the Solution of Systems of Differential Equations
ABSTRACT In this paper, we develop, analyze, and evaluate a parallel algorithm for diagonally exp... more ABSTRACT In this paper, we develop, analyze, and evaluate a parallel algorithm for diagonally explicit Runge-Kutta method of order four (DERK4) for solving systems of differential equations. A timing model has been developed and verified to estimate the execution time of the proposed algorithm. We used the proposed algorithm to solve a predator-prey system and Lorenz equation numerically. The numerical results indicate that the proposed algorithm offers a reduction of both the computation time and storage requirements without losing the desired accuracy. Moreover, the obtained timing results show that the proposed algorithm provides excellent speedup and efficiency for small number of processors.
The Role of Fe<SUB>3</SUB>O<SUB>4</SUB> Nanoparticles on Superconductivity
Journal of Nanoengineering and Nanomanufacturing, 2011
ABSTRACT The effect of nanoscale magnetic pinning sites on the properties of high-temperature sup... more ABSTRACT The effect of nanoscale magnetic pinning sites on the properties of high-temperature superconductor is still controversial. We have investigated the effect of the addition of several concentrations (x = 0.000, 0.005, 0.01, and 0.02) of magnetite (Fe3O4) x nanoparticles on the microstructure, critical temperature, T c and the critical current density, J c in the polycrystalline YBa2Cu3O δ (YBCO) material. The study was conducted using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS) and Vibrating sample magnetometer (VSM) for the magnetization measurements. A gradual increase in a-lattice parameter and decrease in b-lattice parameter was observed with increasing x, while no detectable change was observed in the c lattice parameter. The nanoparticles were observed to significantly agglomerate in the regions of the grain boundaries. Our results show a clear evidence of the suppression of superconductivity after the addition of Fe3O4 nanoparticles. We have found that J c decreases rapidly with increasing x at all temperatures. These results are discussed in terms of the induced disordering in the basal ab plane, the proximity effect and in terms of the interaction of the magnetic nanoparticles with magnetic vortices in the superconducting matrix.
Free energy of formation of small clusters using the BAR method and MD simulations
ABSTRACT Accurate free energy difference calculations based on molecular dynamics (MD) simulation... more ABSTRACT Accurate free energy difference calculations based on molecular dynamics (MD) simulations are still a computational challenge. In this study, the free energy differences between successive cluster sizes of SPC/E-water are calculated using the Bennett acceptance ratio (BAR) method at three temperatures, T = 220K, 240K, and 260K. The simulation results show that the free energy differences of the small clusters scale nicely with the inverse of TcT-1, using the appropriate critical temperature, Tc, of SPC/E-water of 625 K.
The structure of aqueous-alkane nanodroplets
ABSTRACT We conduct in situ small angle X-ray scattering (SAXS) experiments on D2O-nonane nanodro... more ABSTRACT We conduct in situ small angle X-ray scattering (SAXS) experiments on D2O-nonane nanodroplets produced in a supersonic nozzle. Scattering from standard shapes like well-mixed spheres and core-shell structures does not agree with the experimental data. The &#39;lens-on-sphere&#39; models suggested by molecular dynamics simulations fit the scattering data well, but the amount of D2O condensed, based on the SAXS fitting parameters, is only half of that measured by infrared absorption spectroscopy.
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Papers by Abdalla Obeidat