Analytical solution of hydromagnetic flow with Hall effect over a surface stretching with a power‐law velocity

The nonlinear magnetohydrodynamic (MHD) flow problem with Hall current caused by stretching surface having power law velocity distribution is solved by employing homotopy analysis method (HAM). Perturbation solution of stream function, the expression of skin friction coefficient and graphical results in absence of Hall current (Chiam, Int J Eng Sci 33 (1995), 429) are recovered as the limiting cases. It is found that unlike the solution obtained by Chiam (1995), the present results are valid for weak and large magnetic parameters. © 2010 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 27: 937–959, 2011     

Peristaltic motion of a magnetohydrodynamic generalized second‐order fluid in an asymmetric channel

We investigate the peristaltic motion of a magnetohydrodynamic (MHD) generalized second‐order fluid in an asymmetric channel. The governing equations are first modeled and then numerically solved under the long wavelength approximation. Attention has been focused to analyze the shear‐thinning and shear‐thickening effects of the investigated non‐Newtonian fluid, the influence of the magnetic force on the flow, especially the trapping, pumping characteristics caused by the peristalsis of the walls. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2011     

内窥镜中Walter B流体的蠕动流

研究内窥镜中Walter B流体的蠕动流,在圆柱坐标系中建立问题的模型,目的是研究内窥镜对Walter B流体蠕动流的影响.以delta为摄动参数,使用正规的摄动法求出解析解.利用数值积分,求得压力增量和摩擦力的近似解析解.用图形给出了Walter B流体所显现参数的影响.     

Interaction of small vacancy clusters with (1 1 4) twin-boundary in gold

The molecular dynamics simulation technique with many-body and semi-empirical potentials is used to calculate the (1 1 4) twin-boundary in gold at different temperatures. Relaxations are found on both sides of the interface with the same magnitude and the phenomenon of coalescence is observed near the interface. The interactions of single-, di- and tri-vacancies with twin-interface at 300 K on mirror and off-mirror sites are calculated. Off-mirror arrangements are favorable for all vacancy clusters, except for the single-vacancy cluster, which is less repulsive on the mirror site. Vacancy clusters energetically prefer to lie at planes closest to the (1 1 4) interface rather than away from it. The effect of temperature on interaction behavior is also calculated.     

Improved Process for Producing Well-Adhered/Abrasion-Resistant Optical Coatings on an Optical Plastic Substrate

Abstract

A well-adhered and abrasion-resistant coating on a typical optical substrate [polymethylmethacrylate (PMMA)] can be achieved by polymerizing organosilane in a low-temperature polymerization process. The substrate surface can be initially modified with hydrophilic functionalities in a radio-frequency plasma of argon/water vapor mixture in the pressure range 0.05-0.15 mbar to attach hydroxyl functionalities covalently to the substrate surface, which act as “anchorage sites” for polymerizing organosilane. This modified surface is then coated with polyvinyltrimethoxysilane at a power loading in the 20-60 W range and a flow rate of monomer in the 0.7-2.0 cm³-min^?1 range. The polymeric films deposited in this manner on PMMA substrates consistently passed adhesion and abrasive tests even after prolonged storage and thermal cycling in boiling water for at least 10 minutes as exposure to extreme differential thermal expansion conditions. The posttreatment of deposited films with plasmas of inert gases for stress relief had an insignificant effect on peel-off tests and, therefore, it was believed to be not as important as surface modification prior to coatings. The optical properties are essentially not affected by the organosilane coatings irrespective of film thickness, and the coated substrates are virtually transparent above 400 nm.     

Heat transfer analysis in the flow of Waiters＇ B fluid with a convective boundary condition

Radiative heat transfer in the steady two-dimensional flow of Walters＇ B fluid with a non-uniform heat source/sink is investigated. An incompressible fluid is bounded by a stretching porous surface. The convective boundary condition is used for the thermal boundary layer problem. The relevant equations are first simplified under usual boundary layer assumptions and then transformed into a similar form by suitable transformations. Explicit series solutions of velocity and temperature are derived by the homotopy analysis method （HAM）. The dimensionless velocity and temperature gradients at the wall are calculated and discussed.     

A Targeted Review of Current Progress,Challenges and Future Perspective of g-C3N4 based Hybrid Photocatalyst Toward Multidimensional Applications

The increasing demand for searching highly efficient and robust technologies in the context of sustainable energy production totally rely onto the cost-effective energy efficient production technologies. Solar power technology in this regard will perceived to be extensively employed in a variety of ways in the future ahead, in terms of the combustion of petroleum-based pollutants, CO₂ reduction, heterogeneous photocatalysis, as well as the formation of unlimited and sustainable hydrogen gas production. Semiconductor-based photocatalysis is regarded as potentially sustainable solution in this context. g-C₃N₄ is classified as non-metallic semiconductor to overcome this energy demand and enviromental challenges, because of its superior electronic configuration, which has a median band energy of around 2.7 eV, strong photocatalytic stability, and higher light performance. The photocatalytic performance of g-C₃N₄ is perceived to be inadequate, owing to its small surface area along with high rate of charge recombination. However, various synthetic strategies were applied in order to incorporate g-C₃N₄ with different guest materials to increase photocatalytic performance. After these fabrication approaches, the photocatalytic activity was enhanced owing to generation of photoinduced electrons and holes, by improving light absorption ability, and boosting surface area, which provides more space for photocatalytic reaction. In this review, various metals, non-metals, metals oxide, sulfides, and ferrites have been integrated with g-C₃N₄ to form mono, bimetallic, heterojunction, Z-scheme, and S-scheme-based materials for boosting performance. Also, different varieties of g-C₃N₄ were utilized for different aspects of photocatalytic application i. e., water reduction, water oxidation, CO₂ reduction, and photodegradation of dye pollutants, etc. As a consequence, we have assembled a summary of the latest g-C₃N₄ based materials, their uses in solar energy adaption, and proper management of the environment. This research will further well explain the detail of the mechanism of all these photocatalytic processes for the next steps, as well as the age number of new insights in order to overcome the current challenges.