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.     

Assessment of Dewatering Requirements and Dewatering Well Design for an Open Pit Coal Mine in Central Anatolia

The Çeltikçi Coal Basin is a newly discovered coal basin in Central Anatolia where 11 years of open-cut mining has been planned. The bulk of the mining will be conducted below the regional water table; hence, determination of the dewatering requirements and proper design of the dewatering wells plays a critical role. This study (i) defined the dewatering requirements of the open-pit mine, (ii) established a dewatering well design for the area, and (iii) assessed the anticipated impacts of the dewatering activities. For this purpose, a 3-D numerical groundwater flow model was developed using the FEFLOW software. Yearly dewatering requirements were determined under transient conditions. For the dewatering well simulations, two types of dewatering wells were considered: permanent wells located at the open pit boundary that would increase in number as the excavation proceeds and wells located at the periphery of the yearly excavated area that would be operational for about two years. The simulation results indicated that 894 wells were required to satisfy dry working conditions; the average pumping rate throughout the mine life was calculated as 322 L/s. The impacts of open-pit dewatering on groundwater resources were assessed in terms of spring discharge and base flow rates in the nearby Kirmir stream. As a result of dewatering, most of the village water supply springs and fountains will dry up in the area. In addition, the base flow rates to the Kirmir stream will be decreased by 15%.

     

Spatial assessment of site suitability for solar desalination plants: a case study of the coastal regions of Turkey

Clean Technologies and Environmental Policy - Many countries, especially in arid and semiarid regions, suffer from water scarcity because of the decline in the existing freshwater reserves by...     

Modeling and Analytical Solution of Hybrid Thermopiezoelectric Micro Actuator and Performance Study Under Changing of Different Parameters

Micro actuators are an irreplaceable part of motion control in miniaturized systems and are intended to have a high range of deformation, high accuracy, large force, and quick response. In this article, an analytical model for a hybrid thermopiezoelectric micro actuator is developed in which a double lead-zirconnate-titanate piezoceramic (PZT) beam structure consisting of two arms with different lengths are used. Governing differential equation of motion and electrical field are derived and solved. Out of parametric studies it was observed that, under application of temperature and voltage gradients, the deflection of the actuator shows different trends depending on the geometry of the micro actuator and also type of PZT material.     

Boosted hydrogen evolution activity from Sr doped ZnO/CNTs nanocomposite as visible light driven photocatalyst

CNTs were decorated onto Sr doped ZnO nanoparticles to construct an efficient photocatalyst via a facile sol-gel method. The as-fabricated Sr doped ZnO/CNTs with recyclability exhibits Sr and CNTs content dependent hydrogen evolution activit under visible light illumination. The Sr doped ZnO/CNTs photocatalyst shows the highest hydrogen evolution rate of 2732.2 μmolh^?1g^?1, which is 33.7 and 2.83 times higher than pure ZnO and Sr doped ZnO photocatalysts, respectively. The improved hydrogen evolution activity of Sr doped ZnO/CNTs is primarily assigned to high surface area, Sr doping and construction of heterojunction, which can extend the light absorption, decrease the optical band gap and improve the charge separation. Moreover, the underlying photocatalytic mechanism is proposed on the basis of Mott-Schottky study and explains the interfacial charge transfer process from ZnO to CNTs and Sr. This work open new strategies to synthesize CNTs based nanocomposite for hydrogen evolution.     

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...     

Review on Zinc Oxide Nanoparticles: Antibacterial Activity and Toxicity Mechanism

Nano-Micro Letters - Antibacterial activity of zinc oxide nanoparticles (ZnO-NPs) has received significant interest worldwide particularly by the implementation of nanotechnology to synthesize...