THEORETICAL AND COMPUTER MODELS OF 3-DIMENSIONAL GRAIN BOUNDARY MIGRATION WITH MOBILE PARTICLES

In this work, the migration of a three-dimensional (3D) spherical crystal in the presence of mobile particles using a Monte Carlo algorithm was studied. Different concentrations of particles (<i>f</i>) and different particle mobility (<i>M_p</i>) were used. It was found that the grain size reaches a critical radius (<i>R_c</i>) which depends exclusively on <i>f</i>. This dependence can be written as: <i>R_c</i>∝<i>f</i>^1/3. The dynamic equation of grain size evolution and its analytical solution were also found. The analytical solution proposed fits successfully the simulation results. The particle fraction in the grain boundary was also found analytically and it fits the computational data.

Impact of blended learning approach on students’ achievement and mental effort

Most researchers are interested in investigating the impact of a blended learning approach (BLA) on students’ performance, yet this approach’s instructional efficiency has not yet been quantified. Therefore, this research aims is to determine the impact of teacher-created online Moodle-based materials in combination with face-to-face learning on student achievement and mental effort, i.e., to determine the instructional efficiency of applied teaching approaches at physics classes in high school. For this research, we chose to teach students physical principles of direct current, which involves abstract concepts. Using BLA, students can prepare better for a real experiment in the lab, and this approach also creates a safe environment for the student while providing the ability to demonstrate the learned physical phenomena. The Moodle platform course is developed for this purpose and implemented in a BL environment. Students are gradually guided from easier to more difficult concepts in this research, considering the working memory’s capacity and the teaching material requirements. Our results show that the students who used BLA achieved higher scores on the knowledge test, and they also used less mental effort than students that used a conventional teaching approach. We also show that instructional efficiency for BLA is positive and significantly higher than the instructional efficiency of the conventional approach. This research’s results are primarily designed for physics teachers to understand the effects of the BLA better and apply teaching approaches that respect the principles of cognitive development of a child.

A phenomenological approach to anomalous transport in complex or disordered media

We aim to derive a phenomenological approach to link the theories of anomalous transport governed by fractional calculus and stochastic theory with the conductivity behavior governed by the semi-empirical conductivity formalism involving Debye, Cole-Cole, Cole-Davidson, and Havriliak-Negami type conductivity equations. We want to determine the anomalous transport processes in the amorphous semiconductors and insulators by developing a theoretical approach over some mathematical instruments and methods. In this paper, we obtain an analytical expression for the average behavior of conductivity in complex or disordered media via using the fractional-stochastic differential equation, the Fourier-Laplace transform, some natural boundary-initial conditions, and familiar physical relations. We start with the stochastic equation of motion called the Langevin equation, develop its equivalent master equation called Klein-Kramers or Fokker-Planck equation, and consider the time-fractional generalization of the master equation. Once we derive the fractional master equation, then determine the expressions for the mean value of the variables or observables through some calculations and conditions. Finally, we use these expressions in the current density relation to obtain the average conductivity behavior.

Electro-osmosis modulated biologically inspired flow of solid liquid suspension in a channel with complex progressive wave: An application of targeted drugging

Electrokinetic microperistaltic pumps are important biomechanical devices, helps in targeted drugging of sick body parts. The current article is written to focus on mathematical modelling and analysis of some important aspect of such flows in a channel with complex wave. It is considered that solid partilcle are uniformly distributed in the flow and these particle are non-conducting. Parameters such as Particle volume fraction coefficient, Electro-osmotic parameter and Helmholtz-Smoluchowski parameter are specially been focused in this study. Spherical shaped equally sized are uniformly floated in a non-Newtonian Powell-Eyring base fluid. The defined flow problem is modelled and analyzed analytically for the transport of solid liquid suspension. It is accepted that the flow is steady, nonturbulent and propagating waves do have a considerably longer wave-length when compared to amplitude. The conditions and assumptions lead to a model of coupled partial differential equations of order two. The exact results by HPM expansion method are procured and shown accordingly. The predictions about the behaviour of important appearing parameters are displayed using figures. The impact of sundry parameters are analyzed. The application of current study involved transporting/ targeted drug delivery system using Peristaltic micropumps and magnetic field in pharmacological engineering of biofluids like blood.

Role of f(G) Gravity in the Study of Non-Static Complex Systems

The concept of complexity for dynamical spherically symmetric dissipative self-gravitating configuration [1] is generalized in the scenario of modified Gauss-Bonnet gravity. For this purpose, a spherically symmetric fluid with locally anisotropic, dissipative, and non-dissipative configuration is considered. We choose the same complexity factor for the structure as we did for the static case, while we consider the homologous condition for the simplest pattern of evolution. In this approach, we formulate structure scalars that demonstrate the essential properties of the system. A fluid distribution that fulfills the vanishing complexity constraint and proceeds homologously corresponds to isotropic, geodesic, homogeneous, and shear-free fluid. In the dissipative case, the fluid is still geodesic but it is shearing, and there is a wide range of solutions. In the last, the stability of vanishing complexity is examined.

Irreversible Thermodynamics at Surfaces: Inverse Edelstein Effect for Topological Insulator

We employ Onsager’s irreversible thermodynamics (IrTh) to study the Inverse Edelstein effect (IEE) for a non-magnetic material (NM) adjacent to a topological insulator (TI) with a strong spin-orbit interaction. The TI surface state region is treated as quasi two-dimensional (2d). For the IEE, the source is a 3d spin flux incident from the NM that converts, at the NM/TI interface, to a quasi-2d charge current in the TI. For the Edelstein Effect (EE), the source is a quasi-2d charge flux incident from the TI that converts, at the interface, to a three-dimensional (3d) spin flux in the NM. For strong spin-orbit coupling, as considered here, when the 3d spin flux crosses to the 2d TI, the quasi-2d charge current is produced along with a quasi-2d spin accumulation. (For weak spin-orbit coupling, production of charge current and of spin accumulation are distinct processes.) We compute the associated rates of heating.

Exact calculations of the thermal properties of two-electron GaAs quantum dots with inverse-square interactions

In this study, we theoretically scrutinize the effect of the inverse-square interaction on the thermal properties of two electrons trapped in a parabolic GaAs quantum dot. The analytical energy spectrum was used to calculate the thermal properties of the system using the canonical ensemble formalism. It was found that the thermal energy increased with the increase in temperature, while it remained almost constant for sufficiently low temperatures; it was also demonstrated that the inverse-square interaction increased the thermal mean energy. Moreover, the heat capacity increased sharply within a low-temperature window and saturated to the value of 2kB in the high-temperature limit. As expected, entropy increased linearly with increasing temperature. It was also shown that both entropy and heat capacity decreased rapidly when the confinement strength increased (or the dot size decreased) in the low-temperature limit, regardless of the influence of the interaction between the electrons. We also show that the number of allowed states of the system decreased as the interaction strength increased (Z(λ = 0) > Z(λ ≠ 0)). Finally, the stability of the system was investigated through F–T curves. The three-dimensional surface for the temperature-dependent mean energy and heat capacity was also plotted. It should be noted that, for the thermal mean energy, partition function, and Helmholtz free energy, the normal physical behavior of the two-oscillator system with Fermi statistics is recovered for λ → 0. However, heat capacity and entropy show exact two-fermion oscillator system behavior. The most impressive result found in this work is that the inverse-square interaction does not affect the heat capacity and entropy at all despite its noticeable effects on the thermal mean energy. This, in turn, facilitates theoretical studies related to finding the distinctive parameters of quantum dots without going into the heavy calculations resulting from the effects of interactions.

Impact of Global Data Assimilation System atmospheric models on astroparticle showers

We present a methodology to simulate the impact of the atmospheric models in the background particle flux on ground detectors using the Global Data Assimilation System. The methodology was within the ARTI simulation framework developed by the Latin American Giant Observatory Collaboration. The ground level secondary flux simulations were performed with a tropical climate at the city of Bucaramanga, Colombia. To validate our methodology, we built monthly profiles over Malargüe between 2006 and 2011, comparing the maximum atmospheric depth, X_max, with those calculated with the Auger atmospheric option in CORSIKA. The results show significant differences between the predefined CORSIKA atmospheres and their corresponding Global Data Assimilation System atmospheric profiles.

Parametrizations of the Poisson–Schrödinger equations in spherical symmetry

We consider the asymptotically flat standing wave solutions to the Poisson–Schrödinger system of equations. These equations are also known as the Schrödinger–Newton equations and are the Newtonian limit of the Einstein–Klein–Gordon equations. The asymptotically flat standing wave solutions to the Poisson–Schrödinger equations are known as static states. These solutions can be parametrized using a variety of choices of two continuous parameters and one discrete parameter, each having a useful physical-geometrical interpretation. The values of the discrete variable determines the number of nodes (zeros) in the solution. We use numerical inversion techniques to analyze transformations between various informative choices of parametrization by relating each of them to a standard set of three parameters. Based on our computations, we propose explicit formulas for these relationships. Our computations also show that for the standard choice of continuous variables, the zero-node ground state yields a minimum value of a geometrically natural discrete variable. We give an explicit formula for this minimum value. We use these results to confirm two related observations from previous work by the author and others, and suggest additional applications and approaches to understand these phenomena analytically.

Reply to the comment by Amano on “Linear and bent triatomic molecules are not qualitatively different!”

In Amano’s comment on Jensen’s paper, we notice two important misconceptions: (i) Amano overlooks the fact that all features special for a linear molecule originate in the double degeneracy in the bending motion (i.e., in the fact that for a linear triatomic molecule, the description of the bending motion must necessarily also involve the rotation about the axis of least moment of inertia, the a axis, which becomes the molecular axis at equilibrium), and (ii) the expectation value generated from the wavefunction gives an “average” value of the relevant observable (coordinate); the expectation value can, in principle, be obtained experimentally as the average of very many repeated measurements of the observable. In our previous papers on this subject, in particular the paper by Jensen discussed here, we have attempted to explain our results as coherently and “pedagogically” as we can, starting with the fundamental principles of quantum mechanics, and we encourage interested readers to refer to our previous works on the subject. Thus, we maintain our assertion that the vibrationally averaged structure of a linear molecule is observed as being bent, as we have demonstrated previously from both theoretical and experimental viewpoints.