Proceedings of the National Academy of Sciences, India Section A: Physical Sciences最新文献

Nanotechnology research has advanced in the past two decades because of its tunable physicochemical properties. Among the wide range of metal-based nanoparticles, silver nanoparticles (AgNPs) have gained intense research prominence because of their peerless features such as excellent electrical conductivity, catalysis, and a broad range of promising bioactivities such as antioxidant, antibacterial, antifungal, anti-inflammatory, and anticancer effects. In attaining the colloidal stability of silver nanoparticles, capping plays an important role. These capping compounds are believed to provide dual functionality in the synthesis process, acting both as structure-directing and stabilizing agents. Polyvinylpyrrolidone (PVP) is a biocompatible, pH-stable, inert, non-toxic, temperature-resistant, and biodegradable polymer. In the present study, PVP capped silver nanoparticles are synthesized using glucose as a reducing agent, and studied the influence of PVP concentration on silver nanoparticles. Three different ratios of silver nitrate and PVP (1:1, 1:1.5, and 1:2) are taken for silver nanoparticle synthesis. Further, silver nanoparticles obtained are subjected to a series of examinations, including UV Spectrophotometry, SEM, X-Ray Diffraction Spectroscopy, Dynamic Light Scattering, and FTIR. The PVP capped silver nanoparticles are spherical, non-aggregated, polydisperse, and had a unimodal distribution, with diameters ranging from 40 to 100 nm. PVP capped silver nanoparticles are then subjected to antioxidant and antimicrobial activity investigation by spectrometry and agar well diffusion method respectively. The DPPH and the ABTS study revealed the radical scavenging activity of AgNPs. However, the PVP-capped silver nanoparticles did not show any antibacterial activity. This study showed the possibility of the application of PVP-capped AgNPs in the treatment of free radical-related diseases.

The aim of this article is to define the Caputo derivative of bicomplex order for the functions of a bicomplex variable, which we refer to as the Bicomplex Caputo Derivative (BCD) throughout the paper. We achieve BCD via the development of the Caputo derivative of bicomplex order for the bicomplex-valued functions of real variable and discuss some of its significant properties. We also compare BCD with the bicomplex Riemann–Liouville derivative and integral. We demonstrate the advantages of the properties of BCD by finding the derivatives of some elementary bicomplex functions. The useful applications of BCD are found in constructing bicomplex fractional Maxwell’s equations in the vacuum and source-free domains. The solutions of bicomplex fractional Maxwell’s equations are obtained by considering a bicomplex vector field, and it is proved that in this way the number of equations is reduced by half.

In the present article, we present how M-connectedness differs from similar concepts in general topology, and the notion of closed subspace mixed M-topology in mixed M-topological space by extending the concept of closed subspace M-topology. We also define the notions of M-connectedness and M-compactness on mixed M-topological spaces. We investigate different properties of M-connectedness and M-compactness via two subspace mixed M-topologies.

Two-occasion sampling might only provide a snapshot of the phenomenon under investigation. Extending to h occasions allows researchers to capture long-term trends, patterns, and changes that may emerge over time. In h-occasion successive sampling, the effective estimation of population mean is an important factor for agriculture, socioeconomic, pandemics surveys when reliable estimates are required at the h-th occasion (recent-occasion). A difference-type model of an estimator is suggested for the estimation which is escorted with the information on two auxiliary variables. The optimal estimator is the combination of the matched and unmatched sample units in the h-occasion successive sampling. Empirical studies with the competent natural mean estimator and difference type estimator based on bias and mean square errors have been demonstrated in the estimator's efficiency context. A data analysis has been conducted for the applicability to the suggested model. The approach of this work provides valuable insights into long-term trends, developmental trajectories, causal relationships, and the dynamic nature of the real-world problems.

In the presented paper, we present the concept of rough statistical convergence and the set of rough statistical limit points ((st-text {LIM}^r h)) for functions defined on discrete countable amenable semigroups (DCASG) with some properties such as boundedness, closedness and convexity. Then, for functions defined on DCASG, the relationships between (st-text {LIM}^r h) and statistical cluster points are discussed

We present an analysis of the steady two-dimensional flow of chemically reacting and electrically conducting Casson fluid over a permeable flat stretching sheet. The flow is subjected to nonlinear space- dependent stretching as well as magnetic field intensity. The presence of a transverse magnetic field and a saturated porous medium result in the formation of two volumetric body forces that act on the flow field. The consideration of the diffusion-thermos effect (Dufour effect), accounts for additional heat flux due to the concentration gradient. The presence of viscous instability is controlled by introducing Casson fluid and suction at the plate; the less Casson fluidity and the greater the Dufour effect accelerate thermal energy transfer; and an increase in the magnitude of skin friction leads to progressive thinning of the boundary layer, which is required to maintain laminarity of the considered flow.

In this study, moving least squares approach (MLSA) is used for solar radiation (SR) estimation in the selected region. While developing new models with the MLSA, three different weight functions which are Gaussian, cubic spline and Wendland are used. The compatibility of some modified Angström-type equations were tested to estimate of monthly average daily global SR at selected region. The most suitable equation was found by comparing with the values measured and obtained from the equation. In this paper, six different statistical error analysis tests are used in order to compare the performance of new proposed models. According to the results obtained in the selected region, the weight function for which the best performance values are obtained is the cubic spline weight function.

Hybrid numbers are introduced as a linear combination of complex, dual and hyperbolic numbers, where hybrid units satisfy (i^{2}=-1), (epsilon ^{2}=0) and (h^{2}=1), respectively. The main motivation of this study is to present dual hybrid numbers and dual hybrid matrices. In this context, we first give some results of hybrid numbers related to complex and hyperbolic numbers. Afterward, we define hybrid matrix representation of a dual hybrid matrix by introducing dual hybrid matrices whose elements consist of dual hybrid numbers. Since dual hybrid numbers are not commutative, it is necessary to examine the right and left eigenvalues of dual hybrid matrices separately. In this article, we focus on the right eigenvalues of dual hybrid matrices and give some of their properties. Finally, we provide hybrid matrix representations of dual hybrid numbers and support our results with an example

In this study, electrical discharge machining (EDM) was performed on aluminum 7075 reinforced with boron carbide (9 wt%) and titanium diboride (3 wt%) materials. The composites were manufactured via a stir-casting process. The experiments were planned according to the Taguchi design of experiments, and analysis of variance (ANOVA) was used to study the effect of the output parameters on the input parameters. Scanning electron microscopy was used to study the machinability characteristics of the machined surfaces. Finally, the output was optimized using grey relational analysis (GRA), and a confirmation test was conducted to validate the results. The results revealed that the optimal process parameters were input current (IP) = 3 A, pulse-on-time (Ton) = 75 μs, and gap voltage (V) = 50 V. Confirmation experiments corroborated the effectiveness of the GRA-optimized parameters, yielding an enhancement of GRG (grey relational grade) values. Current (IP) emerged as the most significant parameter, contributing 79.45% to the variance, followed by Ton at 8.23% and gap voltage at 4.06%. It was observed that surfaces machined under the optimal process parameters exhibited minimal unevenness compared to surfaces machined under initial and higher-level conditions.