When thin brittle rods such as dry spaghetti pasta are bent beyond their limit curvature, they often break into more than two pieces, typically three or four. With the aim of understanding these multiple breakings, we study the dynamics of a bent rod that is suddenly released at one end. We find that the sudden relaxation of the curvature at this end leads to a burst of flexural waves, whose dy...

Dynamic modulus of elasticity was determined in clearwood samples of eight tropical hardwood species using longitudinal vibrations, flexural vibration and ultrasonic transit-time methods. These samples were subsequently subjected to three point static bending test to determine static modulus of elasticity and modulus of rupture. Acoustic velocity and wood density were found to be independent pa...

Bidirectional frequency tuning in microresonators is demonstrated through the simultaneous use of both mechanical (stretching) and magnetomotive approaches. Stretching is employed to increase the resonance frequency, while the magnetomotive method provides actuation and spring softening. The fabrication process is presented for a double-clamped micromechanical nickel resonator. Lorentz Force is...

OBJECTIVE To test the null hypothesis that neither the flexural properties of orthodontic adhesive resins nor the enamel pre-treatment methods would affect metal bracket debonding behaviours, including enamel fracture. MATERIALS AND METHODS A dimethacrylate-based resin (Transbond XT, TX) and two methyl methacrylate (MMA)-based resins (Super-Bond C&B, SB; an experimental light-cured resin, EXP...

Background. Acrylic resins used in restorative dentistry are the most popular denture base material, because they have good optical properties and small solubility in body fluids. However their mechanical properties are limited and therefore acrylic resins require different methods of reinforcement one of which can be application of different kinds of fibers. Objectives. To investigate the effe...

The aim of this study was to evaluate the effect of plasma treatment using argon and oxygen gases, combined with fiber position on flexural properties of a fiber-reinforced composite. Eleven groups were evaluated, a non-reinforced control group and 10 groups reinforced with InFibra, a woven polyethylene fiber, varying according to the plasma treatment and fiber position. The samples were prepar...

The purpose of this study is to compare the flexural strength values of four different methods for chair side direct transfer methods of implant housing. Materials and Methods: Sixty heat-cured polymethylmethacrylate denture blocks were prepared of size 11 (±0.5) x 8 (±0.5) x 38(±0.5) mm. At the centre a hole of 5mmx8mm dimension was made to secure the implant housing.The Implant Housings were ...

This study evaluated the effect of bleaching agents on bond strength at the dentin/resin interface and the flexural strength of dentin. Forty maxillary canines were selected for the study. In the shear strength test, 40 slabs of intracoronary dentin (5 x 5 mm) obtained from buccal surfaces of the crowns were included in acrylic resin. In the flexural strength test, 40 dentin bars (8 x 2 x 2 mm)...

PURPOSE This study aimed to measure the color change, surface roughness and flexural strength of heat-polymerized acrylic resin after its immersion in denture cleansers, simulating a 180-day use. METHODS Thirty disk-shaped (15mm x 4mm) and 30 rectangular samples (65mm x 10mm x 3.3mm) were prepared from heat-polymerized acrylic resin and immersed in Corega Tabs, Bony Plus, and distilled water....