We investigate the Dirichlet-scalar equivalent of Casimir-Polder forces between an atom and a surface with arbitrary uniaxial corrugations. The complexity of the problem can be reduced to a one-dimensional Green’s function equation along the corrugation which can be solved numerically. Our technique is fully nonperturbative in the height profile of the corrugation. We present explicit results f...

Thanks to the high counting statistics provided by a recent XMM-Newton observation of RX J1856.5–3754 we have discovered that this isolated neutron star pulsates at a period of 7.055 s. This confirms that RX J1856.5–3754 is similar in nature to the other six thermally emitting, nearby neutron stars discovered in soft X–rays with ROSAT. The pulsations are detected at consistent periods in severa...

A numerical study of the unsteady mixed convection heat transfer characteristics of an Ag–water nanofluid confined within a square shape lid-driven cavity has been carried out. The Galerkin weighted residual of the finite element method has been employed to investigate the effects of the periodicity of sinusoidal boundary condition for a wide range of Grashof numbers (Gr) (105 to 107) with the ...

In this paper, we propose a variational formulation to study the singular evolution equations that govern the dynamics of surface modulations on crystals below the roughening temperature. The basic idea of the formulation is to expand the surface shape in terms of a complete set of basis functions and to use a variational principle equivalent to the continuum evolution equations to obtain coupl...

A friction-variable touch panel is capable of presenting virtual bumps and holes on its flat surface through the control of the surface frictionwhen a fingertip slides over it. To improve thepresentation, we developed a friction model of a fingertip sliding over a sinusoidal surface with an amplitude of 0.5–2.5mm and a spatial wavelength of 20–50mm. When a metal ball rolls over a wavy surface w...

We present experimental measurements of light backscattered from double-scale randomly rough surfaces (oceanlike surfaces) with different statistical parameters illuminated at small and large angles of incidence. The surfaces are composed of a small-scale roughness superimposed on a slowly (large-scale) varying surface. The large-scale surfaces are diamond-machined periodic surfaces made on alu...

the micro milling operation is one of the manufacturing processes, which can produce 3d parts in the range of less than a millimetre. miniaturization of components results in increasing the ratio of surface area to volume of components, which in turn increases the role of surface on the component performance. therefore, anticipating the relationship between micro milling parameters and surface ...

In this study, a realistic model for dynamic instability of embedded single-walled nanotubes (SWCNTs) conveying pulsating fluid is presented considering the viscoelastic property of the nanotubes using Kelvin–Voigt model. SWCNTs are placed in longitudinal magnetic fields and modeled by sinusoidal shear deformation beam theory (SSDBT) as well as modified couple stress theory. The effect of slip ...

introduction: side weir structures are extensively used in hydraulic engineering, irrigation and environmental engineering, and it usually consists of a main weir and a lateral channel. side weirs are also used as an emergency structure. this structure is installed on one side or both sides of the main channel to divert the flow from the main channel to the side channel. lateral outflow takes p...

The methods of finite-time thermodynamics are used to find the optimal time path of an Otto cycle with friction and heat leakage. Optimality is defined by maximization of the work per cycle; the system is constrained to operate at a fixed frequency, so the maximum power is obtained. The result is an improvement of about 10% in the effectiveness (second-law efficiency) of a conventional near-sin...