In spite of their popularity in fulfilling aesthetic requirements, plastic brackets still present some disadvantages because of their low elastic modulus, decreased fracture toughness, and reduced wear resistance. Fibre-reinforced composites are well established in dentistry and consist of a polymer matrix in which reinforcing fibres are embedded. Stress is transferred from the polymer matrix t...

The longitudinal stresses in beams subjected to bending also set up transverse stresses within them; they compress the cross section when the beam's curvature is being increased and stretch it when its curvature is being reduced. Analysis shows that transverse stresses rise to a maximum at the neutral axis and increase with both the bending moment applied and the curvature of the beam. These st...

The project aims to study tensile softening behavior of fiber reinforced concrete .Concrete is very much weak in tension but by addition of randomly oriented short crimped steel fibers will change the behavior from brittle to ductile. In the present work, the steel fibers were added at the volume fraction, being 0%, 0.5%, 1%, 1.5% to the normal strength concrete and high strength concrete. The ...

objectives : the purpose of this in vitro study was to compare the marginal adaptation and fracture resistance of a zirconia-based all-ceramic restoration with two preparation designs. materials and methods: twenty-four mandibular premolars were randomly divided into two groups (n=12); the conventional group received a peripheral shoulder preparation and the modified group received a buccal sho...

the effect of ferrite grain size on the fatigue and tensile properties of dual phase steels with a 0.25 volumefraction of martensite (vm) under different heat treatments was investigated. the heat treatments werehomogenized at 1200 oc along with several subsequent normalizations at 910 oc, resulting in differentmicrostructures and mechanical properties. after heat treatment, the obtained steels...

Thin perforated Steel Plate Shear (SPS) Walls are among the most common types of energy dissipating systems. The applied holes reduce the shear strength of the plate and allow to decrease the profile size of the members at the boundary of the panel when these systems are used in the typical design of structures. On the other hand, the different fracture locations of these panels are visible whe...

BACKGROUND most fractures are preceded by falls. OBJECTIVE the aim of this study was to determine whether tests of physical performance are associated with fractures. SUBJECTS a total of 10,998 men aged 65 years or above were recruited. METHODS questionnaires evaluated falls sustained 12 months before administration of the grip strength test, the timed stand test, the six-metre walk test ...

statement of problem: endodontically treated teeth are more prone to fracture. the post and core are often used to provide the necessary retention for prosthetic rehabilitation. objectives: the purpose of this study was to: 1) compare the fracture strength of endodontically treated teeth restored either with nickel-chromium (ni- cr) post or non- precious gold-color alloy (npg) post compared to ...

Rock anisotropy plays an important role in engineering behavior of rocks. Slates are anisotropic rocks which have long been used for gable roof, floor tiles, borrow materials, and other purposes. The slates studied in this research are calcareous and have a porphyro-lepidoblastic texture. To determine the role of the anisotropy on the tensile strength and fracture pattern, two variables includi...

The effect of ferrite grain size on the fatigue and tensile properties of dual phase steels with a 0.25 volume fraction of martensite (Vm) under different heat treatments was investigated. The heat treatments were homogenized at 1200 oC along with several subsequent normalizations at 910 oC, resulting in different microstructures and mechanical properties. After heat treatment, the obtained ste...