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The current research examines the role of chemical reaction, nonlinear thermal radiation and slippage impact on magnetic second-grade fluid flow with diluted dispersion of nanoparticles using a theoretical bioconvection model over an exponentially stretched sheet. There are also new characteristics such as Brownian motion and thermophoresis. In the problem formulation, the boundary layer approximation is used. Using the suitable transformations, the energy, momentum, micro-organisms and concentration equations are generated into nonlinear ordinary differential equations (ODEs). The solution to the resultant problems was calculated via the Homotopy analysis method (HAM). Environmental parameters' effects on velocity, temperature, microbes and concentration profiles are graphically displayed. When comparing the current results to the previous literature, there was also a satisfactory level of agreement. In comparison with a flow based on constant characteristics, the flow with variable thermal conductivity is shown to be significantly different and realistic. The temperature and motile density of the fluid grew in direct proportion to the thermophoresis motion, buoyancy ratio and Brownian motion parameters. Also, the motile density profile decreases down for Pe and Lb while increasing when bioconvection Rayleigh number and buoyancy ratio. This work is significant to bioinspired nanofluid enhanced fuel cells and nanomaterials production techniques, according to these research studies. [ABSTRACT FROM AUTHOR]

The most recent research and developments are driven by colossal permittivity (CP) materials due to their potential use in modern microelectronics and high-energy density storage applications. Even though, to date, many CP materials have been discovered, the task of developing them with the required high performance remains highly challenging. We present a tangible example, polycrystalline ZnO ceramic, that presents a highly frequency-stable CP (> 104) as well as a low dielectric loss (~ 0.3) over a broad temperature range from 278 to 433 K. Multifunctional polycrystalline ZnO nanoceramics are prepared through one-pot hydrothermal route and sintered at 300 °C and 600 °C. The highly magnified scanning electron microscopic images reveal excellent grain growth at high temperature. Temperature-dependent impedance spectroscopy is employed for pellet sintered at (600 °C) to explore different conduction mechanisms at various temperature ranges. The distribution of relaxation times (DRT) method is used to design the best equivalent circuit model for fitting impedance data. The non-Debye behavior of real permittivity (ɛ′) is well explained by fitting with Cole–Cole formalism. The change in the conduction mechanism is estimated around 343 K, and an adiabatic polaronic model is used to estimate activation energies of cations through different electroactive regions. The correlate barrier hopping (CBH) model is applied to measure electrical trapping parameters (like binding energy, hopping distance, barrier height, etc.) at various temperatures. Our finding presents a systematic approach toward frequency-independent ZnO ceramics with a stable colossal permittivity which can potentially be applied to develop energy storage devices. [ABSTRACT FROM AUTHOR]

Experimental investigation was carried out to calculate local void fraction in a vertical tube having 15 mm and 25 mm inside and outside diameter, respectively, using optical fiber probe technique. This work aimed to estimate the average void fraction of the entire test section from the void fraction at the center of the circular channel. Single- and dual-tip optical fiber probes were used. The high-velocity digital camera method was opted to calibrate optical probes. Deformation, deceleration, and drift effect were the main aspects that brought measurement errors. These effects were studied carefully, and the average error of the local void fraction in the bubbly flow measured by the optical probe is -8.4%. Using Bankoff's variable density model for two-phase flow, a model was established to calculate the average void fraction in the test section. Experiments were performed by varying superficial liquid velocity from 0.1 to 2.0 m s−1 and superficial gas velocity from 0 to 10 m s−1. Results showed that the void fraction increased parabolically for the specific values of superficial water velocity. When superficial air velocity was small, a minor change in its velocity caused the void fraction to increase sharply. The void fraction curve became relatively flat when ug > 2 m s−1. Besides, an assessment was carried out using slip ratio and drift flux correlations to validate the present average void fractional data from the optical probe technique. Excellent agreement was seen between present experimental data points and classical void fraction calculation correlations. [ABSTRACT FROM AUTHOR]