The forming limit is an important failure criterion for polycrystalline sheet metals when approving the process. Recent developments in strain measurement technology, e.g., digital image correlation (DIC), enable evolution to be captured continuously and accurately. This new technology would improve measurements if onset of necking detection method was developed accordingly. paper proposes a ba...

Stents for angioplasty have been extensively used to treat coronary diseases. The aim of this study is to analyze the expansion of the stent and the contact with the artery using tube hydroforming simulation. In the simulation, the contact stress and the final shape of the artery after stent expansion process using the Stampack (®;) software will be studied. A model of a commercial stent made o...

We present proper motions of 59 stars of the ROSAT All-Sky Survey (RASS) located in direction of the Chamaeleon star forming region (SFR) in the magnitude range B=5.1 17 mag. Proper motions of the fainter stars were newly derived utilizing survey Schmidt plates from the GSC II plate archive and from a set of special plates taken with the ESO Schmidt telescope. The vector point diagram (VPD) ind...

The staggered charge-order phase of the extended Hubbard model in the atomic limit Abstract We study the phase diagram of the extended Hubbard model in the atomic limit. At zero temperature, the phase diagram decomposes into six regions: three with homogeneous phases (characterized by particle densities = 0, 1, and 2 and staggered charge density = 0) and three with staggered phases (characteriz...

A three-variable model describing the oscillatory activity of a cascade of enzyme reactions is analyzed. A quasi-steady-state approximation reduces the three equations to a system of two equations which admits only a stable steady state. This apparent failure of the quasi-steadystate approximation to describe the limit-cycle oscillations observed in the full, three-variable system is analyzed i...

In Incremental Sheet Forming (ISF) strains can be obtained well above the Forming Limit Curve (FLC) that is applicable to common sheet forming operations like deep drawing and stretching. This paper presents an overview of mechanisms that have been suggested to explain the enhanced formability. The difference between fracture limit and necking limit in sheet metal forming is discussed. The neck...

This article proves that periodic trajectories are generically impossible in a class of continuous-time growth models that allow a locally indeterminate steady state. Those models reducible to the two-dimensional Lotka-Volterra system of equations constitute the class considered here. Knowledge of the presence or absence of the limit cycles allows a global phase diagram of the system to be cons...

The superfluid properties of the attractive Hubbard model in a Zeeman magnetic field, and in the weak coupling regime have been investigated. The temperature and magnetic field dependencies of the order parameter have been analyzed. Furthermore, the temperature vs. magnetic field and temperature vs. spin polarization phase diagrams for the 2D and 3D lattices have been obtained. For some paramet...

In this article, we study Bogdanov-Takens (BT) singularity of a tree-neuron model with time delay. By using the frameworks of CampbellYuan [2] and Faria-Magalhães [4, 5], the normal form on the center manifold is derived for this singularity and hence the corresponding bifurcation diagrams such as Hopf, double limit cycle, and triple limit cycle bifurcations are obtained. Examples are given to ...

Article history: Received 22 April 2008 In final form 18 June 2008 Available online 25 June 2008 0009-2614/$ see front matter 2008 Elsevier B.V. A doi:10.1016/j.cplett.2008.06.061 * Corresponding author. Fax: +1 765 494 0239. E-mail addresses: [email protected] (A. Fer (P. Serra), [email protected] (S. Kais). We present dimensional scaling calculations for the critical parameters needed to...