OBJECTIVE This study evaluated the influence of porcelain (VM9, VITA Zahnfabrik, Germany) thickness on the flexural strength and crack propagation in bilayered zirconia systems (YZ, VITA Zahnfabrik, Germany). MATERIAL AND METHODS Thirty zirconia bars (20.0x4.0x1.0 mm) and six zirconia blocks (12.0x7.5x1.2 mm) were prepared and veneered with porcelain with different thickness: 1 mm, 2 mm, or 3...

OBJECTIVES There has been a growing interest in glass ceramic systems with good esthetics, high fracture resistance and bonding durability, and simplified fabrication techniques using CAD/CAM. The aim of this study is to compare flexural strength before and after heat treatment of two lithium disilicate CAD/CAM blocks, IPS e.max CAD (Ivoclar Vivadent) and Rosetta SM (Hass), and to observe their...

To investigate the influence of carbon fiber (CF) surface treatment on the flexural strength and tribological properties of the short-cut CF/polyimide (PI) composites, pitch-based short-cut CF were treated by rare earth. The CF before and after treatment was examined by X-ray photoelectron spectroscopy (XPS) and by scanning electron microscopy (SEM). The flexural strength of the specimens was d...

We study an extension of the chip-firing game. A given set of admissible moves, called Yamanouchi moves, allows the player to pass from a starting configuration α to a further configuration β. This can be encoded via an action of a certain group, the toppling group, associated with each connected graph. This action gives rise to a generalization of Hall-Littlewood symmetric polynomials and a ne...

Abstract The motion of a toppling iPad is analyzed in detail. Measurements angular velocity and linear acceleration were made for about the edges corners. From analysis velocity, position center mass gyration radii determined. accelerometer was measured using both centrifugal Euler acceleration, with latter measurement providing more accurate data. This experiment could be used first year unive...

PURPOSE The purpose of the present study was to evaluate the flexural strength of the joint between glass-infiltrated alumina frames and the experimental adjusting agent (MA modifier) that contains alumina and magnesia. METHODS A commercially available adjusting agent (Optimizer), a slurry of alumina powder (Alumina modifier), and a bulk specimen (joint-free alumina) were used as controls. Be...

In order to calculate the flexural strength of normal-strength concrete (NSC) beams, the nonlinear actual concrete stress distribution within the compression zone is normally replaced by an equivalent rectangular stress block, with two coefficients of α and β to regulate the intensity and depth of the equivalent stress respectively. For NSC beams design, α and β are usually assumed constant as ...

OBJECTIVES The flexural strengths of veneering ceramics for zirconia were compared. METHODS With 10 different veneering ceramics for zirconia (test group) and three different veneering ceramics for the metal-ceramic technique (control group) three-point flexural strength and biaxial flexural strength according to ISO 6872: 1995 as well as four-point flexural strength according to EN 843-1: 20...

For many industrial parts, their natural resting pose differs from the orientation desired for assembly. We have found that it is possible in many cases to compensate for this difference using a parallel-jaw gripper with fixed orientation. The idea is to arrange contact points on each gripper jaw so that the part is reoriented as it is grasped. We analyze the mechanics of compensatory grasping ...

The highest elevation of the Tibetan Plateau, lying 5,700 m above sea level, occurs within the part of the Lhasa block immediately north of the India-Tibet suture zone (Yarlung Zangbo suture zone, YZSZ), being 700 m higher than the maximum elevation of more northern parts of the plateau. Various mechanisms have been proposed to explain this differentially higher topography and the rock uplift t...