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

In this paper, we consider a nonlinear reaction-diffusion equation with a Caputo-Fabrizio derivative and its solution is obtained by the finite difference collocation method. First, we approximate the Caputo-Fabrizio derivative with the aid of shifted Legendre polynomials. To deal with the time derivative, a finite difference scheme is applied, and to deal with the spatial Caputo-Fabrizio derivative, the shifted Legendre spectral collocation method is used. After using spectral method to the problem, the problem reduces to the system of PDE with time fractional derivative. This system of PDEs is reduced to a system of algebraic equations by applying the finite difference scheme, and the resulting algebraic system is solved with the support of initial conditions. To signify the efficiency and validity of the developed scheme, a few numerical examples are solved whose absolute error between exact and numerical results is presented in tabular form.

In this paper, we present an accelerated Jacobi-gradient-based iterative AJGI algorithm to solve the matrix equation (A{ Z}-overline{ Z}B=C), which is based on algorithms presented by Bayoumi (Appl Math Inf Sci, 2021). The iterative solution converges to the exact solution for any initial value under appropriate assumptions. Numerical examples are provided to support the suggested approach and verify its effectiveness and accuracy when compared to a recent one previously described in Bayoumi (Appl Math Inf Sci, 2021).

A system embracing the anisotropic (left( overrightarrow{p}(cdot ), overrightarrow{q}(cdot )right) )-Laplacian operators is studied. We prove the existence and multiplicity of positive weak solutions for the system, via the critical point theory.

The effect of two types of beam expanders (prismatic and telescopic) on the output intensity and band width of dye laser has been investigated. The prism beam expander is unidimensional and little cumbersome. Two prism beam expanders were tested. The first, composed of two prisms, could lead to a folded resonator; it was short and gave higher power, but with 9.6 pm bandwidth. The second prism beam expander contained four prisms as well as the resonator was longer, but it could have 0.7 pm bandwidth. Concerning the telescopic two-dimensional beam expander, four different beam expanders were used with expanding ratios: 2X, 5X, 10X and 15X. In each case, the bandwidth, the output power and the wavelength stability were investigated. The 10X telescopic beam expander was the best with 0.7 pm bandwidth and good wavelength stability over 6 h of operation.

The present paper suggests a novel, efficient operational matrix technique on the basis of block-pulse functions and Genocchi wavelets to solve time-fractional telegraph equations considering Dirichlet boundary conditions. First, a brief overview of the Genocchi polynomials, corresponding wavelets, and fundamental characteristics is presented. Then, the same functions and their suitable characteristics are employed to formulate the Genocchi wavelet-like operational matrices of fractional integration. Using the suggested technique, the fractional model is reduced into a system of algebraic equations, which is solvable by employing the classical Newton’s iteration technique. A comparison is made between the estimated solutions of the time-fractional telegraph equation and the present approaches, such as the Legendre wavelet and the Fibonacci wavelet method. According to the numerical results, accurate results are obtained using the Genocchi method, and therefore, it is computationally more effective compared to the present approaches.

In the field of differential geometry and mathematical physics, warped products consistently hold a central position. This paper focuses on the advancement of statistical warped products, where we examine the generic submanifolds in a holomorphic statistical manifold. We expand this exploration to study warped product CR-statistical submanifolds, presenting general inequalities in the statistical context. Subsequently, we make use of the concept of warped product CR-statistical submanifolds to introduce the notion of a twisted product CR-statistical submanifold, along with its extension, the doubly twisted product CR-statistical submanifold. Moreover, we demonstrate that a twisted product CR-statistical submanifold inherently qualifies as a CR-product. Additionally, we conclusively prove that no doubly twisted product CR-statistical submanifolds exist except twisted product CR-statistical submanifolds.

The fundamental technique for calculating excited states of nuclei over the Hartree–Fock ground state, as well as for energy density functionals, is known as random phase approximation (RPA). In this work, the nuclear structure of the ¹⁴⁰Ce will be studied within the framework of Hartree–Fock + self-consistent RPA utilizing two Skyrme interaction parameters (SIII, SGII). We obtained a good result for the correlation energy using SIII marginally higher than its experimental value and this indicates the magic number in this nuclei. The single-particle density corresponding to rms of two forces showed that the distribution of the proton density falls off at a lesser distance than that of other densities. It is inferred from the work that the method of Hartree–Fock depending on Skyrme forces within a self-consistent RPA scheme is good for describing the properties of ¹⁴⁰Ce spherical nucleus ground and excitation states.

5-Substituted-1H-tetrazoles were synthesized via the [3 + 2] cycloaddition of NaN₃ and several nitriles using Cu_1-xCo_xFe₂O₄ (x = 0, 0.25, 0.5, 0.75, and 1) nanocatalysts in N,N-dimethylformamide (DMF) at 120 °C. The Cu_0.5Co_0.5Fe₂O₄ nanospinel ferrite is the most active nanocatalyst in comparison to other prepared nanocatalysts. This nanocatalyst was easily separated from the reaction mixture using an external magnet and reused for five cycles without any appreciable loss of catalytic activity. The cost-effective and easy availability of the catalyst, simple methodology, high yield, and easy workup are the extra advantages of this method. The structural characteristics of the catalyst were investigated by scanning electron microscopy, X-ray diffraction, and vibrating sample magnetometer analyses.

Composite films with Ag nanoparticles, which are active in biological applications such as biosensors, wound healing and cancer treatment, have been obtained in recent years on a blend consisting of polylactic acid and polyethylene glycol, which has the feature of working shape recovery. The characteristic signals of PLA and PEG were determined by making functional group analyses with attenuated total reflection infrared spectroscopy (ATR-IR) of polymer composite films obtained by the solution casting method. From the results of thermal analysis with thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), it can be interpreted that Ag nanoparticle increases the initial decomposition temperature (T_i) of the polymer blend, that is, increases its thermal stability. The use of a high PEG ratio showed that the droplets in the scanning electron microscopy (SEM) images of the blend were large, while it was observed that these droplets were almost filled with the increasing Ag nanoparticle ratio. The characteristic XRD diffraction angles of Ag nanoparticles were determined more clearly in the composite containing 20% Ag at 2θ = 38.1°, 44.5°, 64.6° and 77.3°. Finally, when the antimicrobial activities of the composites on L. Monocytogenes, C. perfringens, P. aeruginosa and E. coli O: 157 bacteria are examined, the antimicrobial activity with the highest Ag percentage proves the antimicrobial property of Ag.

Aquilaria malaccensis Lam. is known to produce high-grade agarwood, which is naturally distributed in Indonesia, and their trading has been regulated under the CITES Appendix II. This study aimed to analyze the genetic diversity of wild A. malaccensis from Indonesia. Forty-one samples of A. malaccensis were gathered from various wild populations originating from different islands, including Sumatra mainland, adjacent islands (Bintan and Lingga), West Kalimantan, and Bunguran Island—the northernmost island adjacent to West Kalimantan. Sequencing was performed using trnL-trnF and trnH-psbA. The total sequence (1417 bp) revealed six distinct haplotypes, categorized based on their phytoregion: Sumatra and its adjacent islands Bintan and Lingga, West Kalimantan, and Bunguran Island. Notably, Bunguran displayed the most distinct haplotype, featuring two unique haplotypes and one shared haplotype with the populations of Sumatra and its adjacent islands, Bintan and Lingga. The shared haplotype among Bintan, Lingga, and Bunguran with Sumatra mainland suggests a potential connection to the geographical history of these islands, which were formerly part of Sundaland. The nucleotide diversity (π) was notably low in Bunguran Island (π = 0.00215) and the West Kalimantan population (π = 0.00067), in contrast to Sumatra and its adjacent islands characterized by a nucleotide diversity of 0. Despite this low nucleotide diversity value, the phytoregional populations were genetically differentiated, with the highest differentiation between Bunguran Island and Western Borneo (F_ST = 0.83686). It is suggested that the individual trees represent each haplotype as genetic sources for ex situ conservation and cultivation.