The simplest type of dune is the transverse one, which propagates with invariant profile orthogonally to a fixed wind direction. Here we show, by means of numerical simulations, that transverse dunes are unstable with respect to along-axis perturbations in their profile and decay on the bedrock into barchan dunes. Any forcing modulation amplifies exponentially with growth rate determined by the...

A coupled-mode analysis of 2-D generalized transverse Bragg waveguides (GTBW) with tilted distributed Bragg reflectors is presented. As a result of the absence of inversion symmetry about a plane perpendicular to the guiding stripe, the modes supported by these guides are not separable into the familiar form of transverse standing wave and longitudinal traveling-wave components. This fundamenta...

The web of plate girders in bridges are usually reinforced by welded transverse stiffeners in order to improve their shear capacity.Due to problems associated with field welding and fatigue, welded stiffeners are not suitable for retrofitting existing bridges. Bolted stiffeners are a practical alternative for strengthening girders that are expected to experience shear stress in excess of their ...

We recently analyzed a new class of laser amplifier based on transverse Bragg reflection. We show that the unique properties of Bragg confinement make it possible through modal loss discrimination to achieve single-transverse-mode operation with transverse modal size that is an order of magnitude larger than in lasers that depend on total internal reflection for transverse confinement.

recently, transverse flux permanent magnet generators (tfpmgs) have been proposed as a possible generator in direct drive variable speed wind turbines due to their unique merits. generally, the quality of output power in these systems is lower than multi stage fixed speed systems, because of removing the gears, so it’s important to design these kinds of generators with low ripple and lowest har...

background and aim: one of the key aspects of maternal care is observing the progress of labor. careful assessment of labor progress could provide mothers to be referred on time and could decrease the maternal and neonatal morbidity. this study aimed to compare diagnostic accuracy of purple line with transvers diagonal of michaelis sacral rhomboid to predict labor progress in nulliparous and mu...

A 5th order shear deformation theory considering transverse shear deformation effect as well as transverse normal strain deformation effect is presented for static flexure   analysis of simply supported isotropic plate. The assumed displacement field accounts for non-linear variation of in-plane displacements as well as transverse displacement through the plate thickness. The condition of zero ...

Introduction: Angle and internal position of lateral pterygoid muscle leads to contraction over two half of the mandible in maximum opening and protrusion position so it can affects impression prosthetic procedures. The aim of this study was to evaluate the mandibular flexure in two transverse and antro-posterior dimensions. Methods: Seventy edentulous patients at Mashhad Faculty of Dentistry a...

An efficient C0 continuous two dimensional (2D) finite element (FE) model is developed based on a refined higher order shear deformation theory (RHSDT) for the static analysis of soft core sandwich plate having imperfections at the layer interfaces. In this (RHSDT) theory, the in-plane displacement field for the face sheets and the core is obtained by superposing a globally varying cubic displa...