TY - JOUR AU - Szigeti, Balázs Endre AU - Barna, Imre Ferenc AU - Barnaföldi, Gergely Gábor TI - The Formulation of Scaling Expansion in an Euler-Poisson Dark-Fluid Model JF - UNIVERSE J2 - UNIVERSE-BASEL VL - 9 PY - 2023 IS - 10 PG - 17 SN - 2218-1997 DO - 10.3390/universe9100431 UR - https://m2.mtmt.hu/api/publication/34237297 ID - 34237297 N1 - Export Date: 13 November 2023 LA - English DB - MTMT ER - TY - JOUR AU - Barna, Imre Ferenc AU - Mátyás, László TI - Investigation of incompressible boundary layers with viscous heat conduction JF - AIP CONFERENCE PROCEEDINGS J2 - AIP CONF PROC VL - 2849 PY - 2023 PG - 4 SN - 0094-243X DO - 10.1063/5.0162203 UR - https://m2.mtmt.hu/api/publication/34131465 ID - 34131465 LA - English DB - MTMT ER - TY - JOUR AU - Hriczó, Krisztián AU - Barna, Imre Ferenc TI - Heat and mass transfer of nanofluids containing metallic nanoparticles JF - AIP CONFERENCE PROCEEDINGS J2 - AIP CONF PROC VL - 2849 PY - 2023 IS - 1 PG - 5 SN - 0094-243X DO - 10.1063/5.0162391 UR - https://m2.mtmt.hu/api/publication/34130039 ID - 34130039 LA - English DB - MTMT ER - TY - JOUR AU - Vadászné Bognár, Gabriella AU - Barna, Imre Ferenc AU - Hriczó, Krisztián TI - Investigation of mixed convection nanofluid flow over vertical permeable circular cylinder JF - AIP CONFERENCE PROCEEDINGS J2 - AIP CONF PROC VL - 2849 PY - 2023 IS - 1 PG - 5 SN - 0094-243X DO - 10.1063/5.0162394 UR - https://m2.mtmt.hu/api/publication/34125315 ID - 34125315 LA - English DB - MTMT ER - TY - JOUR AU - Varró, Sándor AU - Hack, Szabolcs AU - Paragi, Gábor AU - Földi, Péter AU - Barna, Imre Ferenc AU - Czirják, Attila TI - Diatomic molecule in a strong infrared laser field: level-shifts and bond-length change due to laser-dressed Morse potential JF - NEW JOURNAL OF PHYSICS J2 - NEW J PHYS VL - 25 PY - 2023 IS - 7 PG - 9 SN - 1367-2630 DO - 10.1088/1367-2630/acde9e UR - https://m2.mtmt.hu/api/publication/34071100 ID - 34071100 N1 - Export Date: 08 March 2024 AB - We present a general mathematical procedure to handle interactions described by a Morse potential in the presence of a strong harmonic excitation. We account for permanent and field-induced terms and their gradients in the dipole moment function, and we derive analytic formulae for the bond-length change and for the shifted energy eigenvalues of the vibrations, by using the Kramers-Henneberger frame. We apply these results to the important cases of H-2 and LiH, driven by a near- or mid-infrared laser in the 10(13) W cm(-2) intensity range. LA - English DB - MTMT ER - TY - JOUR AU - Matyas, Laszlo AU - Barna, Imre Ferenc TI - Even and Odd Self-Similar Solutions of the Diffusion Equation for Infinite Horizon JF - UNIVERSE J2 - UNIVERSE-BASEL VL - 9 PY - 2023 IS - 6 PG - 16 SN - 2218-1997 DO - 10.3390/universe9060264 UR - https://m2.mtmt.hu/api/publication/34062195 ID - 34062195 N1 - Export Date: 08 March 2024 AB - In the description of transport phenomena, diffusion represents an important aspect. In certain cases, the diffusion may appear together with convection. In this paper, we study the diffusion equation with the self-similar Ansatz. With an appropriate change of variables, we have found an original new type of solution of the diffusion equation for infinite horizon. We derive novel even solutions of diffusion equation for the boundary conditions presented. For completeness, the odd solutions are also mentioned as well, as part of the previous works. We have found a countable set of even and odd solutions, of which linear combinations also fulfill the diffusion equation. Finally, the diffusion equation with a constant source term is discussed, which also has even and odd solutions. LA - English DB - MTMT ER - TY - JOUR AU - AL-JANABI, HUMAM KAREEM JALGHAF AU - Kovács, Endre AU - Barna, Imre Ferenc AU - Mátyás, László TI - Analytical Solution and Numerical Simulation of Heat Transfer in Cylindrical- and Spherical-Shaped Bodies JF - COMPUTATION J2 - COMPUTATION VL - 11 PY - 2023 IS - 7 PG - 21 SN - 2079-3197 DO - 10.3390/computation11070131 UR - https://m2.mtmt.hu/api/publication/34052884 ID - 34052884 N1 - Export Date: 08 March 2024 AB - New analytical solutions of the heat conduction equation obtained by utilizing a self-similar Ansatz are presented in cylindrical and spherical coordinates. Then, these solutions are reproduced with high accuracy using recent explicit and unconditionally stable finite difference methods. After this, real experimental data from the literature regarding a heated cylinder are reproduced using the explicit numerical methods as well as using Finite Element Methods (FEM) ANSYS workbench. Convection and nonlinear radiation are also considered on the boundary of the cylinder. The verification results showed that the numerical methods have a high accuracy to deal with cylindrical and spherical bodies; also, the comparison of the temperatures for all approaches showed that the explicit methods are more accurate than the commercial software. LA - English DB - MTMT ER - TY - JOUR AU - Al-Magsoosi, Ali Habeeb Askar AU - Nagy, Ádám AU - Barna, Imre Ferenc AU - Kovács, Endre TI - Analytical and Numerical Results for the Diffusion-Reaction Equation When the Reaction Coefficient Depends on Simultaneously the Space and Time Coordinates JF - COMPUTATION J2 - COMPUTATION VL - 11 PY - 2023 IS - 7 PG - 27 SN - 2079-3197 DO - 10.3390/computation11070127 UR - https://m2.mtmt.hu/api/publication/34041856 ID - 34041856 N1 - Export Date: 08 March 2024 AB - We utilize the travelling-wave Ansatz to obtain novel analytical solutions to the linear diffusion–reaction equation. The reaction term is a function of time and space simultaneously, firstly in a Lorentzian form and secondly in a cosine travelling-wave form. The new solutions contain the Heun functions in the first case and the Mathieu functions for the second case, and therefore are highly nontrivial. We use these solutions to test some non-conventional explicit and stable numerical methods against the standard explicit and implicit methods, where in the latter case the algebraic equation system is solved by the preconditioned conjugate gradient and the GMRES solvers. After this verification, we also calculate the transient temperature of a 2D surface subjected to the cooling effect of the wind, which is a function of space and time again. We obtain that the explicit stable methods can reach the accuracy of the implicit solvers in orders of magnitude shorter time. LA - English DB - MTMT ER - TY - JOUR AU - Barna, Imre Ferenc AU - Pocsai, Mihály András AU - Tőkési, Károly TI - Ab Initio Double-Differential Ionization Cross-Section Calculations in Antiproton–Helium Collisions JF - ATOMS J2 - ATOMS VL - 11 PY - 2023 IS - 4 PG - 13 SN - 2218-2004 DO - 10.3390/atoms11040074 UR - https://m2.mtmt.hu/api/publication/33773520 ID - 33773520 N1 - Export Date: 08 March 2024 AB - We present ionization cross-sections for antiproton and helium collisions based on an ab initio time-dependent coupled channel method. In our calculations, a finite basis set of regular helium Coulomb wave packets and Slater function were used. The semiclassical approximation was applied with the time-dependent Coulomb potential to describe the antiproton–electron interaction. Three different projectile energies were considered as 10, 50 and 100 keV. We found clear evidence for the formation of the anti-cusp in the differential distributions. LA - English DB - MTMT ER - TY - JOUR AU - Saleh, Mahmoud AU - Kovács, Endre AU - Barna, Imre Ferenc TI - Analytical and Numerical Results for the Transient Diffusion Equation with Diffusion Coefficient Depending on Both Space and Time JF - ALGORITHMS J2 - ALGORITHMS VL - 16 PY - 2023 IS - 4 PG - 22 SN - 1999-4893 DO - 10.3390/a16040184 UR - https://m2.mtmt.hu/api/publication/33723054 ID - 33723054 N1 - Export Date: 08 March 2024 AB - The time-dependent diffusion equation is studied, where the diffusion coefficient itself depends simultaneously on space and time. First, a family of novel, nontrivial analytical solutions is constructed in one space dimension with the classical self-similar Ansatz. Then, the analytical solution for two different sets of parameters is reproduced by 18 explicit numerical methods. Fourteen of these time integrators are recent unconditionally stable algorithms, which are often much more efficient than the mainstream explicit methods. Finally, the adaptive time-step version of some of these algorithms are created and tested versus widespread algorithms, such as the Runge–Kutta–Fehlberg solver. LA - English DB - MTMT ER -