A theoretical framework is provided for determining the self-thermophoretic velocity of a light irradiated spheroidal Janus nanoparticle consisting of symmetric dielectric and perfectly conducting semi-spheroids. The analysis is based on solving the linearized Joule heating problem due to uniform laser irradiance and on explicitly determining the temperature fields inside and outside the particle. We employ the thermoelectric (Peltier- Seebeck) methodology to find the surface self - induced temperature gradient and the related slip velocity which determines the autonomous phoretic (self - propulsion) mobility of the Janus particle. Simplified explicit expressions for the self - thermophoretic velocities of spheroidal (prolate and oblate) Janus particles in terms of their aspect ratios are found and few practical limiting cases (i.e., sphere, disk and needle) are also discussed.

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Carbon steel cantilever beams are widely used in many applications in aerospace, civil and mechanical engineering. Pitting corrosion is a phenomenon which places severe limitations on the design of such applications. As such, understanding this phenomenon and the methods to deal with it, are of a great importance. This paper presents numerical investigation by using F. E. (Finite Element) simulation on the load carrying capacity of corroded cantilever beams with pitting corrosion damage. The pitting corrosion hole shape has been modeled using ASTM G46 Standard Guide. Several different cases of pitting corrosion, represented by hemispherical holes, were modeled and examined by using ANSYS computer program. Clamped edge constraint was used on one end, while the other end was free. In these F. E. models, element of Solid95 was used and comparison to Bernoulli-Euler theory was made. The effect of the radius of the pitting corrosion holes on the stresses in the beam was examined in comparison to yield stress. It has been found that the M. S. (Margin of Safety) has been reduced gradually with increasing radii. Agreement with Bernoulli-Euler theory has been achieved only for small radii. Moreover, three methods of pitting corrosion repairs were examined, together with Bernoulli-Euler theory comparison: 1) Regular surface repair; 2) Extension surface repair; and 3) "Handy Removal". It was found that extension surface repair has the highest M. S. value.

Combined MHD and electroosmotic Jeffery-Hamel flow of Nano fluid type inside a wedge (inclined walls) with non-linear viscosity and wall friction are investigated analytically. As a result of similarity relations, one nonlinear ordinary differential equation is obtained and solved analytically with the appropriate assumptions   2 0, 0 20 f f    . Moreover, excellent agreement was found between the obtained analytic solution and suggested simple parabolic approximation. Although it was found that in case where more effects are gradually being considered, a slight difference is emerged, but the most dramatic change between solutions occurs when solid to fluid ratio gets significant value. In addition, suitable match in the quantitatively and qualitatively aspects was found between literature results and obtained solution. In addition, analytical solution parametric investigation was performed for specific parameters choice. It was found that the normalized velocity was found to decrease gradually with the tangential direction progress and/or with friction coefficient increase. However, the normalized velocity profile gets higher values as long as the solid to fluid ratio increases. Additionally, Reynolds, Hartmann and solid volume fraction coefficient increase (separately or all together) have raised the normalized velocity function values. Finally, unprevail distinguished cases were introduced to understand flow complexity. It was found that the electrical field magnitude effect is significantly, especially for small friction coefficient values and for high wedge semi angle. Also, the combination between small friction coefficient values including small parameter flow values (Re and Ha numbers) and high electrically field may lead to unoptimized course of normalized velocity profile. The last case that was examined is concerned with friction coefficient variation effect on the normalized velocity profile for different values of wedge semi angle with high electric field for specific parameters choice. It was found that increasing friction coefficient leads to normalized velocity profile consolidation.

The following work describes the process of finding the flow and the temperature fields for a given ventilation system configuration. In order to simplify the problem, the flow was characterized as 2D, incompressible, viscous and in constant state. First, the governing equations in terms of the stream function, vorticity and Reynolds number have been developed. The obtained mathematical model for the flow field is actually a pair of coupled elliptical partial differential equations. Solving the resulting equations was performed using SOR (successive over-relaxation) methods following upwind second-order finite differences.In the second stage, the temperature field was numerically calculated using the flow field data obtained in the first stage. In fact, as expected, the flow has been advanced from the left inlet opening to the right outlet opening. Also, the main flow was creating a vortex while above the main flow large vortex has been generated and surrounded by several small vortices around it. Last but not least, Reynolds (Re) number influence on the solution nature has been expressed by flow expansion in the whole ventilation cell. Finally, comparison between different Re numbers have proved the flow type dependency on the Re number and its effect on the temperature field.

This essay deals with the expansion of the classical problem, known as the impulsive start of motion over a cylindrical body. It was found that the boundary layer (BL) velocity profiles are similar to the classical results of Goldstein & Rosenhead. Moreover, high order (fourth approximation) of the velocity was developed and no effect on the BL velocity profile solution was found, confirming Watson theory. On the other hand, for the third order approximation, the separation angle was found to be time dependent. Also, the maximum velocity value was found to increase with respect to the time constant increase. An opposite effect of the BL velocity occurs for the maximum shear stress value, such that it decreases over time. The recent findings are supported by Riley and Nam literature results.

This study deals with the influence of radial body forces on FGM and non-FGM pressure vessels. It contains an extended overview of pressure vessels made from both kinds of material. Furthermore, full mathematical development of stress-strain field for both kinds of cylindrical vessels while being influenced by body forces has been performed. In addition, a new power law model for FGM materials was suggested and discussed. Finally, tables of composed plastic-elastic states are discussed.

This paper presents, aerodynamics coefficients calculation (Lifting & drag coefficients, pressure central location) of Trapeze wing shape configurations for different aspect ratios (ARs) values by using improved vortex lattice method (VLM), compared with finite-wing and slender body theories. The planar wing was divided into N panels of the size: 6X6 with trapezoid shape panels. As expected, for high ARs the VLM solution for the lifting coefficient is coincided with the finite wing theory whereas for small ARs (<1) it is coincided with the slender body theory (~1). Afterwards, we obtained that the calculated VLM induced drag becomes closer to the finitewing theory as the AR value is increased.