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The unique physical and chemical properties of silica fume enhance the compressive strength and water resistance of cement mortar. The study aims to investigate the effect of silica fume in cement mixes in terms of strength-gaining characteristics and water-resistance attributes. The silica fume was added in amounts of 0%, 10%, 20%, and 25% as a partial cement replacement for the production of mortar. A total of 120 mortar cubes were prepared with steel molds of 50 × 50 × 50 mm dimensions. Two water-cement ratios (w/c) of 0.4 and 0.5 were utilized to investigate the water-resistance properties. A water-resistant property was calculated using the compressive strength ratio in the saturated surface dry (SSD) state to the oven-dry condition. The compressive strength ratios in SSD and the oven-dry state were measured after curing in water for 3, 7, 28, 45, and 90 days. After 90 days of curing, the sample with a water-cement ratio of 0.4 exhibited the greatest compressive strength and the highest ratio of SSD to the oven-dry state. The higher SSD to oven-dry strength ratio shows the silica fume possesses superior water resistance. This study concludes that silica fume possesses great pozzolanic activity and excellent resistance to water. The incorporation of silica fume creates a concrete composition that enables the construction of durable concrete structures. [ABSTRACT FROM AUTHOR]

The demand for cement-free concrete is increasing worldwide to make the construction industry closer to being sustainable. The current research’s main objective was to develop self-compacting fiber-reinforced geopolymer concrete using waste/recycled materials. Steel wire from an old discarded tire was cut to make steel fibers. Wheat straw ash, an agricultural waste material, was utilized as the primary binder, and alkali-activated solutions were used as the precursors. Further, nano-silica (NS) was added from 0.5 to 3.0%, and waste tire steel fibers (WTSF) were added from 1 to 3.5% by binder content in different mixes. To evaluate the characteristics of different concrete, tests were performed, such as compressive, split tensile, and flexural strength for mechanical properties and sorptivity, rapid chloride penetration (RCP), and drying shrinkage tests for durability properties. It was noted that at 2.5% NS and 3.0% WTSF, the strength increases as 71.5, 6.5, and 8.2 MPa strength was achieved at 90 days for compressive, split tensile and flexural strength. For the RCP test, all samples were categorized as “low” in electrical conductance, micro-strains for drying shrinkage all came in an acceptable range for all samples, and sorptivity values were higher in earlier curing phases than in later phases of concrete. To understand the phase analysis of concrete, x-ray diffraction (XRD) analysis was performed, and it was revealed that the M5 mix (2.5% NS + 3.0% WTSF) had the highest peaks of C-S-H, N-A-S-H, and C-A-S-H, which demonstrates the densified microstructure of concrete with addition of nano-silica. [ABSTRACT FROM AUTHOR]

Fuzzy soft set theory presented by Maji et al. (J Fuzzy Math 9(3):589–602, 2001) and soft set theory presented by Molodtsov (Comput Math Appl 37(3):19–31, 1999) are important ideas in decision-making problems. They can be used to model uncertainty and make decisions under uncertainty. A single-valued neutrosophic soft set (svnf-set) is a hybrid model of a single-valued neutrosophic set and fuzzy soft set that is shown in this paper. The novel concept of single-valued neutrosophic soft topology (svnft) is defined to discuss topological structure of (svnf-set). Some fundamental properties of svnft and their related results are studied. It is good to use the proposed models of svnf-sets and svnft to figure out how to deal with uncertainty in real life. Thus, svnft is a generalization of fuzzy soft topology and fuzzy intuitionistic soft topology. Moreover, after giving the definition of a single-valued neutrosophic soft base svnf-base, we also added the concept of svnft. Finally, we set up the concept of single-valued neutrosophic soft closure spaces and show that the initial single-valued neutrosophic soft closure structures are real, which is what we did. From this fact, the category SVNSC is considered as a topological category over SET. [ABSTRACT FROM AUTHOR]

In this article, we are interested in studying the asymptotic behavior of fourth-order neutral differential equations. Despite the growing interest in studying the oscillatory behavior of delay differential equations of second-order, fourth-order equations have received less attention. We get more than one criterion to check the oscillation by the generalized Riccati method and the integral average technique. Our results are an extension and complement to some results published in the literature. Examples are given to prove the significance of new theorems. [ABSTRACT FROM AUTHOR]

In this work, we develop an efficient numerical scheme based on the method of lines (MOL) to investigate the interesting phenomenon of collisions and reflections of optical solitons. The established scheme is of second order in space and of fourth order in time with an explicit nature. We deduce stability restrictions using the von Neumann stability analysis. We consider a (2 + 1) -dimensional system of a coupled nonlinear Schrödinger equation as a general model of nonlinear Schrödinger-type equations. We consider several numerical experiments to demonstrate the robustness of the scheme in capturing many scenarios of collisions and reflections of the optical solitons related to nonlinear Schrödinger-type equations. We verify the scheme accuracy through computing the conserved invariants and comparing the present results with some existing ones in the literature. [ABSTRACT FROM AUTHOR]

In this paper, the prime orbit theorem and Mertens' orbit theorem are proved for a shift dynamical system of infinite type called the Motzkin shift. Instead of using the zeta function approach to find the asymptotic formulas, different and more direct methods are used in the proof without any complicated theoretical discussion. [ABSTRACT FROM AUTHOR]

In this paper, we get crucial estimates of fundamental sums that involve the number of closed orbits of the Dyck shift. These estimates are given as the prime orbit theorem, Mertens' orbit theorem, Meissel's orbit theorem and Dirichlet series. Different and more direct methods are used in the proofs without any complicated theoretical discussions. [ABSTRACT FROM AUTHOR]