Iranian Journal of Science and Technology, Transactions A: Science最新文献

In this paper, we construct a Durrmeyer type modification of (alpha)-Bernstein operators based upon Pölya distribution. For these newly defined operators, we establish an approximation theorem by means of Bohman–Korovkin’s theorem and analyze the rate of convergence by using modulus of continuity and Lipschitz-type space. To study the asymptotic behaviour of our operators, we estimate Voronovskaya type theorem and Grüss Voronovskaya type theorem. Finally, with the help of a graph generated using Maple, we show the convergence of our operators to certain functions.

In this paper, we employed the mathematical model to show the aggregation effect of algal blooms to explore the relationship between cyanobacteria blooms and filter-feeding fish. The existence of equilibrium points and the conditions for the stability of equilibrium points have been derived. A proposed mathematical model is used to investigate transcritical bifurcation, Hopf bifurcation and direction of Hopf bifurcation. The stability of the limit cycle occurring through Hopf-bifurcation is carried out. Bifurcation analysis supports the theoretical explanation. We observed that if the cyanobacteria aggregation area increased over a certain threshold, filter-feeding fish would become extinct. Cyanobacteria aggregation can influence the eating habits of filter-feeding fish and protect them from predators. Numerical simulations show that the aggregation effect of cyanobacteria plays a significant role in the dynamic connection. A weakly nonlinear analysis has been carried out to determine the magnitude of the Turing instability. Furthermore, we explored the Turing Insatiability condition for spatial patterns resulting from spatial systems and evaluated the pattern formation over time. Our analytical findings were corroborated by numerical solutions, which showed that the coexistence of all population classes is dependent on diffusion.

This study investigates a class of fractional integral equations involving Hadamard fractional integral operator. By virtue of Petryshyn’s fixed point theorem and the measure of non-compactness, we establish existence results for solutions within the Banach algebra C[1, a], (a>1). Notably, we do not impose the bounded requirement, commonly known as the “Sublinear condition”, as seen in existing literature. Through theoretical analysis, we demonstrate the existence of solutions for the considered class of Hadamard-type fractional integral equations. Furthermore, we investigate the uniqueness of solutions under certain restrictive conditions. Additionally, we provide some illustrative examples to illustrate the accuracy and applicability of our results. Finally, conclusions and future scopes are also presented.

In this work we find generators for the stabilizer subgroup of the point at infinity, (mathbf {q_infty }), of the Picard modular groups (U(3, 1; mathcal {O}_d)) where (d = 2, 7, 11). In the case of (d=2), the generating set consists of two Heisenberg rotations and three Heisenberg translations. In the cases of (d=7) and (d=11) the generating sets consist of two Heisenberg rotations and two Heisenberg translations.

Information about the first excited 2⁺, 4⁺ and 6⁺ energy levels of atomic nuclei have an important place in nuclear structure studies as it contains a lot of information. Therefore, determining these energy levels with high accuracy allows obtaining more accurate information about the nucleus. In addition to being obtained experimentally, these energy levels can also be calculated with various theoretical models. In this study, we worked on predicting these energy levels with high accuracy by machine learning with existing experimental data using artificial intelligence approaches. According to the results of the study in which we used five different artificial intelligence approaches, we found that these alternative approach models are suitable for this purpose. We compared the obtained results with existing experimental data in the literature and with each other.

Plasma jet (PJ) nanoparticle synthesis is a highly efficient and cutting-edge technique that offers several advantages. It is an environmentally friendly and efficient process that results in the production of nanoparticles (NPs) characterized by their small dimensions and consistent forms. In this paper, a non-thermal plasma (cold plasma) system was used to synthesise copper oxide nanoparticles (CuO NPs) using a high-voltage power supply. A high-voltage of 15 kV and an argon gas (Ar) flow rate of 2 l/min were used for three time periods (2–6 min) to synthesise copper oxide nanoparticles. Distilled water placed in a 10 ml laboratory beaker was used in the NPs synthesis. The results of X-ray diffraction (XRD) analysis of copper oxide nanoparticles (CuO NPs) showed that they have a monoclinic crystal structure, and the crystalline size of these nanoparticles ranged from 23 to 28 nm. The optical properties of CuO NPs showed that they have an absorption spectrum at 310 nm with a gradual increase in the energy gap (Eg) value (2.25–2.86) ± 0.1 eV as the synthesis time of the nanoparticles increased. The Atomic Force Microscope (AFM) analysis results also showed a uniform shape and almost homogeneous distribution of CuO NPs with a grain size ranging from (15–22) ± 1.10 nm. In addition, the Field Emission Scanning Electron Microscope (FE-SEM) images of CuO NPs showed that their structure is spherical and has a uniform symmetry and arrangement, as the size of these NPs ranged from (15–30) ± 1.60 nm. Finally, the results of the zeta potential (ZP) of the CuO NPs showed negative surface charge values ​​ranging between (-26 ± 2.2 to -20 ± 1.1) mV in all three synthesis times, which indicates the stability of these synthetic nanoparticles and the permanent stability of the surface dispersion.

This paper explores tuberculosis (TB), a highly infectious disease primarily targeting the lungs but also capable of affecting other parts of the body, including the nervous system, bones, and joints. Despite extensive prevention efforts, TB remains a significant public health challenge. This study investigates the dynamics of TB through vaccination, awareness campaigns, and intervention strategies, employing a deterministic modeling approach. The analysis focuses on six compartmental models to represent different population groups: vaccinated, susceptible, latent, infected, isolated, and recovered individuals. It was discovered that the model is Ulam-Hyers stable and has a unique solution. After achieving the equilibrium of the disease-free, we used the next generation matrix to determine the (R_{0}) in order to evaluate the possible Transmission of the ailment. Additionally, we investigate the endemic equilibrium and sensitivity analysis. We use Laplace-Adomian decomposition method to produce numerical solutions, and the convergence of the solution is verified using conventional mathematical approaches. The outcomes of the Caputo fractional-order numerical simulations show that the current state is strongly influenced by the host’s prior medical history.

Long-term biodiversity exploration and monitoring are essential for understanding temporal and spatial patterns of diversity, as well as assessing the effectiveness of current conservation efforts. Despite increased research in the western Indo-Pacific, recent ichthyological studies continue to uncover a high frequency of new species discoveries and recent findings. In this study, we examine the presence, morphology, scale, and otolith shape variations, osteology, distribution, and molecular phylogenetic relationships of Epinephelus malabaricus, known as the Malabar grouper, from the northwestern of the Oman Sea. The scales were cycloid, ranging from oval/ovoid to oval/true oval and oval/reversed ovoid in different regions of the body, with a fluted rostral margin. The lateral-line scales featured a wide, elongated canal that widened in the anterior region and bifurcated at the end. The otoliths were oval-oblong, with a sinuate/irregular dorsal margin, sinuate inferior edge, and an indented, irregular rear edge. The sulcus groove was medium in size and heterosulcoid, with an ostial opening. The ostium was funnel-shaped, while the cauda was tubular, strongly curved, and ended near the ventral margin. The colliculum was heteromorph, characterized by a well-developed ridge-like crista superior and a generally underdeveloped crista inferior. The spinal column comprised 10 precaudal and 14 caudal vertebrae, totaling 24 vertebrae. Mitochondrial COI-based DNA barcoding sequences demonstrated that some species of the genus Epinephelus are nested within the Mycteroperca clade, indicating that these genera are not monophyletic. However, E. malabaricus remains within the Epinephelus clade. This study contributes to our comprehension of the taxonomy and genetic variation of E. malabaricus and underscores the importance of ongoing biodiversity monitoring in the region.

In this paper, we study some repeated-root two-dimensional cyclic and constacyclic codes over a finite field (mathbb {F}=mathbb {F}_q). We obtain the generator matrices and generator polynomials of these codes and their duals. We also investigate when such codes are self-dual.

We proposed a discrete Lindley distribution with a nabla structure, taking into account the nature of the underlying environmental data. To understand the behavior of the proposed distribution and how it can be effectively used in the considered scenario, some its mathematical properties are studied. These properties include generation functions, moments, index of dispersion, order statistics, and asymptotic distribution of the extremes. We have also studied its application and found that the proposed statistical model is one of the better choices in modeling the environmental indicators, such as concentration of carbon monoxide, nitrogen oxide, and number of precipitation days.