Journal of Applied Mathematics and Physics

Journal Information
ISSN / EISSN : 2327-4352 / 2327-4379
Published by: Scientific Research Publishing, Inc. (10.4236)
Total articles ≅ 1,862
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Latest articles in this journal

Magne Stensland
Journal of Applied Mathematics and Physics, Volume 10, pp 703-713; https://doi.org/10.4236/jamp.2022.103050

Abstract:
In this paper, we define a group of solutions x(t) that are sine and cosine to the upper limit of integration in a non-elementary integral that can be arbitrary. We will also define a group of solutions x(t) that are equal to the amplitude. This is a generalized amplitude function. We are using Abel’s methods, described by Armitage and Eberlein. And finally, we define an exponential function whose exponent is the product of a complex number and the upper limit of integration in a non-elementary integral that can be arbitrary. At least three groups of non-elementary functions are special cases of this complex function.
Stephan J. G. Gift
Journal of Applied Mathematics and Physics, Volume 10, pp 322-332; https://doi.org/10.4236/jamp.2022.102025

Abstract:
In this paper tests by Maxwell and Gift that search for a preferred frame or ether arising from movement through that frame using Jupiter’s moon Io are reviewed and discussed. Unlike the Michelson-Morley second-order experiment which unsuccessfully attempted to detect the orbital motion of the Earth relative to the ether, these tests are both first-order and therefore are unaffected by the second-order effects of length contraction and clock retardation. The test by Maxwell utilizes the delay in the eclipse of Io as the Earth orbits the Sun in an attempt to detect ether drift resulting from the galactic movement of the Sun. This test requires a 6-year duration for its full execution and was never performed because of practical difficulties. The test first presented by Gift can be conducted over a few days and employs the observed variation of the period of Io as the Earth moves toward or away from Jupiter. The result is a positive detection of ether drift arising from the orbital motion of the Earth. The detected ether drift is evidence of a preferred frame which we argue corresponds to the solar system barycentric or sun-centered inertial (SCI) frame.
Shengyong Zhang
Journal of Applied Mathematics and Physics, Volume 10, pp 1432-1442; https://doi.org/10.4236/jamp.2022.105101

Abstract:
Lightweight design has a significant impact on reducing fuel consumption and harmful emission of conventional vehicles and improving driving range of electric vehicles. Reducing the thickness of components in vehicle bodies and closures is an efficient approach for weight reduction. Thickness reduction, however, will reduce structural stiffness, especially in the presence of lateral displacements of buckling when critical stress is reached. In this paper, nonlinear FEA models of a thin-walled beam with variable thickness are developed for calculating the changes of beam stiffness as to thickness reduction in the pre- and post-buckling stages. Next, these stiffness values are used to calculate gauge sensitivity of the beam, which changes with respect to beam thickness changes. It is concluded that the presence of buckling will reduce the beam stiffness, worsen the stress uniformity, and increase the gauge sensitivity value of the beam.
Reza R. Ahangar
Journal of Applied Mathematics and Physics, Volume 10, pp 1066-1082; https://doi.org/10.4236/jamp.2022.104073

Abstract:
The principles of the HIV-AIDS epidemics are established based on the subpopulation 1) Susceptible; 2) HIV-infected; 3) AIDS-infected; 4) Immunized. The immunized subset of the population in this paper is the total individuals who were infected and cured or immunized by vaccination. The immunized group can be identified by removing individuals from the susceptible group. A general mathematical model is developed for HIV-AIDS epidemics with Vaccination to understand the spread of the virus throughout the population. Particularly we use numerical simulation with some values of parameters to predict the number of infected individuals during a certain period in a population and the effect of vaccine to reduce infected group and increase the number of immunized individuals. Further, we expand the research to special cases with no vaccinations. A special case is when the removal subset of the population is empty, or there is no recovery in this epidemic. We also can consider the total infected number is equal to the sum of the HIV infected and the number of AIDS infected. As a result, one can reduce four-stage HIV-AIDS investigation to a three-stage of SIR. With this introduction and modification, the numerical simulation can be developed the Monte Carlo simulation method in SIR case to verify the Validity of the HIV-AIDS model.
Walid J. Azzam, Fatima S. Jaber, Ghufran M. Ahmed
Journal of Applied Mathematics and Physics, Volume 10, pp 1083-1088; https://doi.org/10.4236/jamp.2022.104074

Abstract:
Gamma-ray bursts (GRBs) are the most intense and powerful explosions in the universe. Based on their observed duration, they are traditionally divided into long bursts whose observed duration equals or exceeds 2 s, and short bursts whose observed duration is less than 2 s. Several GRB energy and luminosity correlations have been discovered for long gamma-ray bursts. Two important correlations are the Amati relation and the Yonetoku relation. The Amati relation is a correlation between the intrinsic peak energy, Ep,i, obtained from the νFν spectrum and the equivalent isotropic energy, Eiso, while the Yonetoku relation is a correlation between Ep,i and the peak isotropic luminosity, Liso. In this paper, we use a recent data sample that includes both long and short GRBs to compare these two correlations for the two groups of bursts. We also compare the Eiso-Liso plane for these two types of bursts. Our results indicate that both long and short bursts adhere to these two correlations but with different normalizations. We also find that the Eiso-Liso plane is similar for both types of GRBs but is shifted to lower values of Eiso for short GRBs.
Mengdi Zheng, Xiaohui Xu, Juhe Sun
Journal of Applied Mathematics and Physics, Volume 10, pp 1113-1125; https://doi.org/10.4236/jamp.2022.104078

Abstract:
In this paper, we study the p-order cone constraint stochastic variational inequality problem. We first take the sample average approximation method to deal with the expectation and gain an approximation problem, further the rationality is given. When the underlying function is Lipschitz continuous, we acquire a projection and contraction algorithm to solve the approximation problem. In the end, the method is applied to some numerical experiments and the effectiveness of the algorithm is verified.
Zhenghui Song, Pingping Zhang
Journal of Applied Mathematics and Physics, Volume 10, pp 1019-1027; https://doi.org/10.4236/jamp.2022.104069

Abstract:
For stabilized saddle-point problems, we apply the two iteration parameters idea for regularized Hermitian and skew-Hermitian splitting (RHSS) method and establish accelerated RHSS (ARHSS) iteration method. Theoretical analysis shows that the ARHSS method converges unconditionally to the unique solution of the saddle point problem. Finally, we use a numerical example to confirm the effectiveness of the method.
Junzheng Wang, Lijun Wang
Journal of Applied Mathematics and Physics, Volume 10, pp 1028-1035; https://doi.org/10.4236/jamp.2022.104070

Abstract:
By simply adjusting the temperature and the number of materials, rod-like ZnO with different morphology, such as ZnO nanoneedles, were synthesized by a flexible thermal evaporation method. The ZnO nanorod array has the lowest turn-on field, the highest current density, and the highest emission efficiency due to its good contact with the substrate and relatively weak field shielding effect. Experiments show that the morphology and orientation of one-dimensional ZnO nanomaterials have a great influence on its conduction field and emission current density, and the nanoarrays also contribute to electron emission. The research results have a certain reference value for the application of ZnO nanorod arrays as cathode materials for field emission devices.
Pirooz Mohazzabi, Gabrielle Richardson, Gwendolyn Richardson
Journal of Applied Mathematics and Physics, Volume 10, pp 1240-1246; https://doi.org/10.4236/jamp.2022.104087

Abstract:
In a previous article, a model for the coronavirus pandemic was developed. This model was based on simple, uninhibited population growth with rate of infection assumed to be proportional to the existing infected population. Validity of this model was verified by testing it against the infection case data published by the Center for Disease Control and the World Health Organization for the United States and the world, respectively. Discrepancies between infection case data and model predictions can be accounted for by implementation of infection prevention measures enforced during the pandemic. The goal of this article is to explore which prevention measures were most effective in reducing the spread of coronavirus in the United States. It turns out that among various prevention measures implemented, lockdown is by far the most effective one.
Yukai Wang
Journal of Applied Mathematics and Physics, Volume 10, pp 1105-1112; https://doi.org/10.4236/jamp.2022.104077

Abstract:
We propose a metamaterial structure that can achieve electromagnetically induced transparency and polarization—independent of the incident wave. The structure consists of a regular octagonal frame and four L-shaped metal wires arranged periodically. There is a strong transparent window at 4.28 GHz. Our calculation results are in good agreement with the simulation results. When changing the excitation polarization of the incident wave, the transmission spectrum remains stable. Furthermore, when we adjust the permittivity of the medium in front of the metamaterial, the frequency of the transmission valley shifts linearly with the change in permittivity. This structure can be independent of the polarization of the incident wave and has potential inspiration in fields such as sensing.
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