In this paper, the dynamical behavior of the accelerated expansion of the universe is studied within the framework of f(T) gravity by considering a well-motivated functional form of f(T). A specific form of the Hubble parameter is assumed, which under two different cases, leads to two distinct cosmological models expressed in terms of the redshift parameter H(z), providing insights into cosmic dynamics. These models are employed to explore the expansion history of the universe and the evolution of several cosmological parameters. Using Bayesian statistical techniques based on the χ^2-minimization method, the median values of the model parameters are determined for both the cosmic chronometer (CC) and the joint (CC + Pantheon) datasets. The evolution of the deceleration parameter, energy density, pressure and the equation of state parameter for dark energy is analyzed. Additionally, the validity of the energy conditions and the nature of the statefinder diagnostic are examined. The present age of the universe is also estimated for the proposed models.
The United Nations is endeavoring for global sustainable development. Consequently, researchers have directed investigations around alkali-activated matrix/material (AAM). GGBFS-based AAM has shown enormous potential to replace cement-based matrix; however, the difficulties encountered in GGBFS-based AAM are low workability, faster setting time and high risk of efflorescence, which are generally addressed using secondary precursors. Various international standards are also available, which serve as guidelines for development of AAM. Bureau of Indian Standard (BIS) has also come up with IS 17452: 2020, which serves as a guideline for development of alkali-activated concrete. But, the scope of IS 17452: 2020 lists GGBFS, fly ash, metakaolin, calcined clay and silica fumes as the only precursor materials for AAM. It explicitly recommends the use of GGBFS-Fly ash combination for alkali-activated concrete. Different secondary precursors with varying chemical composition and intrinsic properties have been used to overcome the issues in GGBFS-based AAM. The different intrinsic properties, especially the chemical composition and reactivity of secondary precursor affect the behavior of GGBFS-based AAM differently. The effect of these secondary precursors, classified into three different categories based on chemical composition criteria, has not been previously reviewed for GGBFS-based AAM. Therefore, the present article is an attempt to review the effect of each category of classified secondary precursor on GGBFS-based AAM. Initially, all secondary precursors were classified into high calcium aluminosilicates, low calcium aluminosilicates and siliceous precursor categories. The effect of including secondary precursors of a particular category on fresh properties, mechanical properties, efflorescence, transport properties, durability properties and microstructure of GGBFS-based AAM has been reviewed. The key findings of the review state that the material having CaO percentage greater than GGBFS actually behaves as a high calcium aluminosilicate precursor, whereas material having CaO percentage less than GGBFS behaves as low calcium aluminosilicate precursor, in GGBFS-based AAM. This review will help engineers, researchers, other professionals, etc., in classifying the material into different categories of precursor classification. It will also help in the judicious selection of secondary precursor from the appropriate category for enhancing the desired properties of GGBFS-based AAM. Moreover, the outcomes of the review will also help in upgrading IS 17452: 2020.
Currently, the development of luminescent materials is a major focus of research. In particular, inorganic phosphor-based compounds have been widely utilized for different types of applications including cathode ray tubes (CRTs), lamp industries; field emission displays (FEDs), radiation dosimetry, and white light emitting diodes (WLEDs). In this research, we successfully synthesized single-host Ca14Zn6Al10O35: Dy3+/Sm3+ by using the wet chemical method to achieve white light emission. XRD analysis confirmed the phase purity of Ca14Zn6Al10O35. SEM images showed that the phosphor materials tend to form agglomerates. Photoluminescence (PL) measurements of Ca14Zn6Al10O35:Dy3+ doped phosphors demonstrated efficient excitation at 353 nm, with prominent emission bands at 488 nm (blue) and 575 nm (yellow). Co-doping with Sm3+ ionsresulted in strong blue to red emissions. The color qualities of the luminous prepared samples were calculated using the Commission Internationale de l'Eclairage (CIE) coordinates. Therefore, these findings result suggest that Dy3+/Sm3+ co-doped Ca14Zn6Al10O35 phosphors, when excited by UV-LEDs could be suitable for producing white light emitting diodes and display devices.
A high-order numerical method is proposed for solving a two-dimensional time-fractional diffusion equation with weak singularity at the initial time. The method employs L2-1 _σ scheme on a graded temporal mesh for discretization of time fractional derivative and a compact alternating direction implicit (ADI) scheme for discretization of space derivatives. The unconditional stability and convergence of the method in the H^1 -norm are established theoretically. Numerical experiments are carried out and confirm a fourth-order spatial accuracy and temporal convergence rate of min{rα , 1+α} , where α∈ (0,1) denotes the order of the fractional derivative. A comparison is made between the present ADI method and the Non-ADI scheme to justify the advantage of our method. It is shown that the present ADI method attains higher accuracy and requires less computational time. The graded mesh approach effectively handles the weak singularity at the initial time t = 0 .
The behavior of pile foundations under combined vertical and lateral loads and moments was investigated. Lateral loads originated from traffic, seismic events, wind, vessel wakes, and earth pressure. Moments resulted from the eccentricity of vertical loads, column-pile fixity, and the resultant lateral load. To prevent buckling instability in specific scenarios, a minimum pile diameter was required based on the unsupported length above the point of fixity. A review of existing methods for analyzing laterally loaded single piles to determine the depth of fixity revealed conflicting positions among them. To address this discrepancy, depth of fixity values derived from finite element analysis were used as a benchmark for verification against these established methods. The analysis demonstrated that the computed depth of fixity varied significantly depending on the method applied. Although a finite element approach was proposed to determine an appropriate depth of fixity, the depths calculated using coefficient-based methods showed relatively good agreement with the finite element results.
