Generalized differential quadrature analysis of MHD mixed convective motion of Casson fluids past an isothermal irregular slender geometry via Cattaneo–Christov's approach

Classical Fourier's theory is well-known in continuum physics and thermal sciences. However, the primary drawback of this law is that it contradicts the principle of causality. To explore the thermal relaxation time characteristic, Cattaneo–Christov's theory is adopted thermally. In this regard, the features of magnetohydrodynamic (MHD) mixed convective flows of Casson fluids over an impermeable irregular sheet are revealed numerically. In addition, the resulting system of partial differential equations is altered via practical transformations into nonlinear ordinary differential equations. An advanced numerical algorithm is developed in this respect to get higher approximations for temperature and velocity fields, as well as their corresponding wall gradients. For validating our numerical code, the current outcomes are compared with the available literature results. Moreover, it is revealed that the velocity field is more prominent in the suction flow situation as compared with the injection flow case. It is also found that the Casson fluid is hastened in the case of lower yield stress. Larger values of thermal relaxation parameters create a lessening trend in the temperature distribution and its related boundary layer breadth.     

Advanced Friction–Wear Behavior of Organic Brake Pads Using a Newly Developed System

The objective of this study was to investigate the influence of an advanced performance system on the tribological behavior of brake pad material using a specially designed brake pad tester system following standard SAE J-661. The tribological behavior and friction and wear characteristics of the organic brake pad samples were evaluated. During braking tests, the samples, in contact with a cast iron disk, were studied at different disc speeds, temperatures, and braking cycles under a constant pressure. In order to understand the friction and wear behavior, the unworn surfaces, worn surfaces, and wear debris were characterized by means of scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX). Furthermore, the surface characteristics and differences in the wear modes of the brake pad samples were examined. Wear debris was permitted to deform the brake pad surfaces, leading to friction layers and enabling the estimation of the friction behavior of the brake pads. The results showed that the best friction–wear behavior was obtained with lower braking cycles at low speeds and temperature. Thus, the newly developed brake pad tester system proved very effective in evaluating the performance of the brake pad samples.     

Destructive and non-destructive evaluation of concrete for optimum sand to aggregate volume ratio

Aggregates are the biggest contributor to concrete volume and are a crucial parameter in dictating its mechanical properties. As such, a detailed experimental investigation was carried out to evaluate the effect of sand-to-aggregate volume ratio (s/a) on the mechanical properties of concrete utilizing both destructive and non-destructive testing (employing UPV (ultrasonic pulse velocity) measurements). For investigation, standard cylindrical concrete samples were made with different s/a (0.36, 0.40, 0.44, 0.48, 0.52, and 0.56), cement content (340 and 450 kg/m³), water-to-cement ratio (0.45 and 0.50), and maximum aggregate size (12 and 19 mm). The effect of these design parameters on the 7, 14, and 28 d compressive strength, tensile strength, elastic modulus, and UPV of concrete were assessed. The careful analysis demonstrates that aggregate proportions and size need to be optimized for formulating mix designs; optimum ratios of s/a were found to be 0.40 and 0.44 for the maximum aggregate size of 12 and 19 mm, respectively, irrespective of the W/C (water-to-cement) and cement content.     

Incremental gravitational search algorithm for high-dimensional benchmark functions

Neural Computing and Applications - In this study, gravitational search algorithm (GSA), which is a powerful optimization algorithm developed in recent years and based on physics, is improved by...     

The design of multiple feedback topology Chebyshev low-pass active filter with average differential evolution algorithm

Neural Computing and Applications - This study presents the design of a tenth-order multiple feedback Chebyshev low-pass filter (MF-C-LPF). Component selection and gain calculation of filters are...     

Multi carrier energy systems and energy hubs: Comprehensive review,survey and recommendations

In this paper, the multi carrier energy (MCE) systems are reviewed from different point of views including mathematical models, integrated components and technologies, uncertainty management, planning objectives, environmental pollution, resilience, and robustness. The basic of MCE systems is formed by combination of cooling, heating and power (CCHP). The natural gas and electricity are the main inputs to MCE systems and the cooling, heating, and electricity are the common outputs. The regular energy converters in the MCE systems are combined heat and power (CHP), gas boiler, absorption-electrical chillers, power to gas (P2G) and fuel-cell. The generic energy storages are electrical, heating, cooling, hydrogen, carbon dioxide (CO₂) and hydro systems.     

Inorganic thermoelectric materials: A review

Thermoelectric generator, which converts heat into electrical energy, has great potential to power portable devices. Nevertheless, the efficiency of a thermoelectric generator suffers due to inefficient thermoelectric material performance. In the last two decades, the performance of inorganic thermoelectric materials has been significantly advanced through rigorous efforts and novel techniques. In this review, major issues and recent advancements that are associated with the efficiency of inorganic thermoelectric materials are encapsulated. In addition, miscellaneous optimization strategies, such as band engineering, energy filtering, modulation doping, and low dimensional materials to improve the performance of inorganic thermoelectric materials are reported. The methodological reviews and analyses showed that all these techniques have significantly enhanced the Seebeck coefficient, electrical conductivity, and reduced the thermal conductivity, consequently, improved ZT value to 2.42, 2.6, and 1.85 for near-room, medium, and high temperature inorganic thermoelectric material, respectively. Moreover, this review also focuses on the performance of silicon nanowires and their common fabrication techniques, which have the potential for thermoelectric power generation. Finally, the key outcomes along with future directions from this review are discussed at the end of this article.