The effect of prepolymerized particle fillers on fracture toughness of four commercial composite resins was studied. The ground surface morphology was examined with a field emission scanning electron microscope. Fracture toughness was determined by using single edge notched specimens. Acoustic Emission (AE), which is the elastic wave due to the release of energy from the localized sources of ma...

The aim of this study was to clarify the effects of micro surface defects introduced by the focused ion beam (FIB) technique on the fracture strength of ceramics. Three-point bending tests on alumina-silicon carbide (Al₂O₃/SiC) ceramic composites containing crack-like surface defects introduced by FIB were carried out. A surface defect with area in the range 19 to 35 µm was introduced at the ce...

background: previous anatomic and radiological studies have described the relationship of the clavicle to major neurovascular structures in healthy subjects. we were curious about this relationship in patients with a clavicle fracture and if it is different from non-fractured clavicles.   methods: we retrospectively identified all patients with a clavicle fracture between july 2001 and october ...

The torsion property and rotary fatigue fracture behavior of Smart K file and R reamer made of nickel titanium alloy have been studied by means of Shimadzu Autograph DDS-10T universal tester and man-made cyclic system with curved copper tubes as simulated root canal. The instrument surface and the cyclic fatigue fracture surface have been investigated by optical microscope and scanning electro...

OBJECTIVE This research aimed at comparing the qualitative chemical compositions and the surface morphology of fracture regions of eight types of Nickel/Titanium (NiTi) conventional wires, superelastic and heat-activated (GAC, TP, Ormco, Masel, Morelli and Unitek), to the wires with addition of copper (CuNiTi 27ºC and 35ºC, Ormco) after traction test. METHODS The analyses were performed in a ...

A direct determination of the fractal dimensions of a fracture surface is essential for a better understanding of its complete topographic characteristics. In this paper, a laser profilometer is employed to measure the topography of a rock’s fracture surface. With the use of the triangular prism surface area and projective covering methods, the resultant data set enables us to directly determin...

the effects of isothermal aging at temperatures between 550-850 ?c for durations of 1-100 h on microstructure, tensile properties, and impact fracture behavior of 316l austenitic stainless steel weld metal have been investigated. for this purpose, various techniques including metallographic observations, measurement of ferrite content using ferritscope, and fractographic investigations have bee...

Abstract: Rotating bending fatigue tests have been performed using smooth specimens of a rolled AZ31 magnesium alloy in laboratory air at ambient temperature. Fatigue strength and characteristic was evaluated and fracture mechanism was discussed on the basis fracture surface analysis. Electrical polishing (EP) as well as deep rolling (ball burnishing (BB)) U-notched specimens were performed on ...

statement of problem: dental resin composites are becoming prevalent in restorative dentistry and have almost replaced amalgam nowadays. consequently, their mechanical properties and durability are critical. objectives: the aim of this study was to produce pyrex glass nano-particles by wet milling process and use them as reinforcement in dental resins for anterior restorations and then examinat...

rails fracture by the growth of fatigue crack or critical crack is one of the prevalent defects in railway. the rail fracture, failure and stress analysis should be studied in order to prevention of rail fracture. in this paper, new formulation of contact stress for two rolling bodies is presented, where the results are closed to the hertz stress formulation. moreover, stress analysis is done b...