Analytical approach on magnetohydrodynamic Casson fluid flow past a stretching sheet via Adomian decomposition method

Flow phenomena of three-dimensional conducting Casson fluid through a stretching sheet are proposed in the present investigation with the impact of the magnetic parameter in a permeable medium. The adaptation of particular transformations is useful to modify the governing equations into their nondimensional as well as the ordinary form. However, these transformed equations are nonlinear and approximate analytical methods for the solution of the complex form of governing equations. In particular, the Adomian decomposition method is proposed for the solution. The behavior of several variables, such as the magnetic and porous matrix, on the flow profile as well as the rate of shear stress, are discussed via graphs and tables. The conformity of the current result with the earlier study shows a road map for further investigation. The major concluding remarks are; the retardation in the velocity distribution is rendered due to an increase in the Casson parameter moreover, the Casson parameter favors in reducing the rate of shear stress coefficient in magnitude.     

Acidification of the electrolyte during the galvanic corrosion of AA7075: A numerical and experimental study

The electrochemical interactions between aluminum alloy 7075 and low-carbon steels under gelled electrolytes were studied. Such electrolytes provided the opportunity to investigate both thick and thin electrolyte systems. The electrolyte was chemically modified to visually track the acidic fronts during the anodic reaction and the subsequent hydrolysis process. Two mathematical models were validated for both thick and ultrathin electrolytes. The acidification of thick electrolytes was extended some millimeters beyond the aluminum alloy surface, whereas the acidic front was localized next to the metallic joint using ultrathin electrolytes. The combination of both numerical and experimental results allows proving (and explaining why) that the acidification process is more aggressive under dilute than under concentrated electrolytes.     

Local jet pattern: a robust descriptor for texture classification

Multimedia Tools and Applications - Methods based on locally encoded image features have recently become popular for texture classification tasks, particularly in the existence of large intra-class...     

微观表面形貌对螺旋槽液膜密封空化发生的影响

为探索微观表面形貌对液膜密封空化的影响,基于满足质量守恒的JFO空化模型及坐标变换,建立考虑微观表面形貌的双坝区螺旋槽液膜密封数学模型;采用有限体积法离散求解控制方程,综合分析表面粗糙度、周向波度和径向锥度对螺旋槽液膜密封空化发生的影响规律。结果表明:相比而言,密封面计入微观表面形貌后,摩擦副液膜中空穴区发生位置分散且形状不规则;以空化面积比为判据,较大表面粗糙度对液膜空化促生虽起到积极作用,但数据较小,可忽略不计;锥度对液膜中空穴促生和抑制影响有限,波幅的增加显著促进液膜中空穴的发生;高频波数时,正锥度有利于降低液膜空化面积比,抑制空穴。     

Characterization of superficial modification of ferrous rusted substrates subjected to dechlorination-electrochemical process

Preservation of archaeological artefacts after their removal from saline media is a difficult task due to the chloride content of the oxide layers which are unstable in atmospheric conditions, especially if the relative humidity exceeds 85%. For this reason, removal of chlorides from rust layers is one of the priorities of conservationists or restorers of historical artefacts. However, removal of chloride ions is not an easy procedure because of the many considerations involved in the process. In this research, artificially pre-rusted iron samples and an actual historical cannonball were subject to a dechlorination process in a potassium hydroxide solution to measure constant chloride release in a bulk solution. After the chloride removal process, a commercial protective layer was applied to the rust for stabilization purposes. It was calculated that the kinetics of the dechlorination process is driven by diffusion behaviour following Fick’s second law. When this diffusion process prevails, the dechlorination extraction affects the integrity of rust layers as is demonstrated with scanning electron microscopy and X-ray diffraction analyses. It was proven that the chloride removal procedure causes the studied iron layers to stiffen, provoking superficial modification and, in some cases, fractures of the rust. By means of electrochemical impedance spectroscopy it was calculated that the magnitude of the positive effect of the dechlorinated samples depends on the protective features of the rust. Therefore, this research reveals that an efficient chloride removal procedure depends on the electrochemical properties of the dechlorination process and the initial morphology of the iron rust.     

Parallel prefix operations on GPU: tridiagonal system solvers and scan operators

The Journal of Supercomputing - Modern GPUs can achieve high computing power at low cost, but still requires much time and effort. Tridiagonal system and scan solvers are one example of widely used...     

Platinum nanoparticles decorated on graphitic carbon nitride-ZIF-67 composite support: An electrocatalyst for the oxidation of butanol in fuel cell applications

In the present study, we report an eco-friendly and simple route to design and synthesize novel nanocomposite catalyst based on platinum nanoparticles anchored on binary support of graphitic carbon nitride (g-C₃N₄) and cobalt-metal-organic framework (ZIF-67). For this purpose, ZIF-67 was prepared by precipitation method and g-C₃N₄ was prepared through thermal polymerization method. Later, ZIF-67 and g-C₃N₄ were hybridized through sonication to get homogeneous g–C₃N₄–ZIF-67 nanocomposite support material. Platinum nanoparticles (PtNPs) were uniformly deposited on g–C₃N₄–ZIF-67 by an electrochemical method. The as-developed nanocatalyst was characterized by morphological, structural and electrochemical techniques. The electrocatalytic activity of PtNPs@g–C₃N₄–ZIF-67 nanocatalyst towards butanol oxidation was evaluated via CV, CA, LSV and EIS in an alkaline medium. Results revealed that the proposed catalyst showed greatly enhanced electrooxidation of butanol in terms of high magnificent current density, lower oxidation potential, excellent long-term stability, large surface area, low charge transfer resistance and less toxic ability. Enhanced catalytic performance of the proposed catalyst could be ascribed to the synergistic effect of g–C₃N₄–ZIF-67 nanocomposite and PtNPs. The PtNPs@g–C₃N₄–ZIF-67 catalyst holds promising potential applications to be used as an anodic electrocatalyst for the development of high-performance alkaline fuel cells.