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This work introduces a three-dimensional, highly nonlinear quadratic oscillator with no linear terms in its equations. Most of the quadratic ordinary differential equations (ODEs) such as Chen, Rossler, and Lorenz have at least one linear term in their equations. Very few quadratic systems have been introduced and all of their terms are nonlinear. Considering this point, a new quadratic system with no linear term is introduced. This oscillator is analyzed by mathematical tools such as bifurcation and Lyapunov exponent diagrams. It is revealed that this system can generate different behaviors such as limit cycle, torus, and chaos for its different parameters’ sets. Besides, the basins of attractions for this system are investigated. As a result, it is revealed that this system’s attractor is self-excited. In addition, the analog circuit of this oscillator is designed and analyzed to assess the feasibility of the system’s chaotic solution. The PSpice simulations confirm the theoretical analysis. The oscillator’s time series complexity is also investigated using sample entropy. It is revealed that this system can generate dynamics with different sample entropies by changing parameters. Finally, impulsive control is applied to the system to represent a possible solution for stabilizing the system.

Cement-based materials are increasingly and widely employed in infrastructure development; however, they pollute our environment by generating carbon dioxide, which is detrimental to our civilization. In self-cleaning concrete, photocatalysts accelerate the decomposition of organic particles; thus, photocatalytic degradation of gaseous pollutants could reduce pollution. The incorporation of photocatalytic components enhanced the mechanical self-cleaning properties of cement mortar. In this study, 4–6 percent by weight of rutile TiO2 was added to mortar, and the results were compared to those of a control sample. On the proposed mortar cubes, both fresh mortar and hardening mortar experiments were conducted. Because the initial and final setting times of TiO2 differ from those of conventional cement mortar, the surplus TiO2water-cement ratio had to be modified. The adaptability of the sol-gel method enables the use of various process parameters to influence the properties of the produced TiO2 nanoparticles. The compressive strength was calculated for 7, 14, 21, and 28 days, and an ultrasonic velocity test was performed after 28 days. On mortar samples, acid and sulfate attack experiments were performed. The M-3 mortar mixture containing 5% rutile exhibited the highest level of strength compared to the other mixtures. The M-3 exhibits a strength that is 10.96% greater than that of the control mix. The impact of acid and sulfate attack on the strength of mix M-2 is relatively modest in comparison to other mixtures. Using RhB (rhodamine color) discoloration under UV light, such as sunlight, the photocatalytic mortar is concentrated; a typical test for self-cleaning cementitious materials reveals the presence of more photocatalytic material, which yields the best results. [ABSTRACT FROM AUTHOR]

Copper-coated steel wires (5 numbers) were uniformly reinforced in AA336 aluminium alloy using squeeze casting process. Microstructure of castings was examined, and dry sliding wear test was performed by considering the factors viz., load (10–50 N), velocity (1–5 m/s) and sliding distance (500–2500 m). Response surface methodology was used to design the experiments by considering three factors, five levels central composite design. A regression model was developed to predict the weight loss of composites and checked its adequacy using significance tests, analysis of variance and confirmation tests. Worn surfaces of composite were investigated using field emission scanning electron microscope and reported with wear mechanisms. Dry sliding wear parameters were optimised for obtaining minimum weight loss. Microstructure of casting showed the reinforcement of steel wires in AA336 aluminium alloy and copper coating on steel wires offered better interface bonding between matrix and reinforcement. Response surface plots revealed that weight loss of composites increased with increasing load and sliding distance. Worn surface of composites showed fine grooves at lower loads and delamination was observed at higher loads. 18.1 N load, 2.41 m/s velocity and 2094 m sliding distance were observed as optimum dry sliding wear parameters for obtaining minimum weight loss. [ABSTRACT FROM AUTHOR]