AIM The aim of this study was to determine the wettability of different hydrophilic and hydrophobic elastomeric impression materials and the gypsum castability. MATERIALS AND METHODS The wettability was evaluated by determining the contact angles of different elastomeric impression materials. The contact angle was determined by placing a drop of aqueous solution of calcium sulfate dihydrate o...

In this paper, we construct the bilinear identities for wave functions of an extended Kadomtsev-Petviashvili (KP) hierarchy, which is KP hierarchy with particular flows (2008, Phys. Lett. A, 372: 3819). By introducing auxiliary parameter (denoted by $z$), whose flow corresponds to so-called squared eigenfunction symmetry find tau-function hierarchy. It shown that will generate all Hirota's equa...

In this paper, we are interested in the construction of a bilinear pseudodifferential calculus. We define some symbolic classes which contains those of Coifman-Meyer. These new classes allow us to consider operators closely related to the bilinear Hilbert transform. We give a description of the action of our bilinear operators on Sobolev spaces. These classes also have a “nice” behavior through...

This article is concerned with the question of whether Marcinkiewicz multipliers on R2n give rise to bilinear multipliers on R×R. We show that this is not always the case. Moreover, we find necessary and sufficient conditions for such bilinear multipliers to be bounded. These conditions in particular imply that a slight logarithmic modification of the Marcinkiewicz condition gives multipliers f...

The purpose of introducing ultrasonic vibrations in the tube hydroforming process is to create more formability by obtaining a lower corner radius, improve thickness distribution of the wall and provide good tribological conditions at the tube and the die interface. Vibrations imposed on the die create alternating gaps which improve the formability in the tube hydroforming process in the presen...

We calculate the minimal surface bounded by four-sided figures whose projection on a plane is a rectangle, starting with the bilinear interpolation and using, for smoothness, the Chebyshev polynomial expansion in our discretized numerical algorithm to get closer to satisfying the zero mean curvature condition. We report values for both the bilinear and improved areas, suggesting a quantitative ...