Transport and retention of colloid tracers were evaluated in standard petrographic thin sections, prepared from saprolite (Cr horizons) formed from fractured sedimentary rocks, using epi-fluorescence microscopy. Thin sections prepared from dismantled hydrogeological columns revealed four domains of macropores with apparent apertures ranging from 1 to 500 Am. Colloid retention occurred within bo...

Objective: The main aim of this study was to compare fracture load and fracture mode of yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) and metal-ceramic (MC) molar crowns using a modified test set-up to produce fractures similar to those seen in vivo, i.e. fractures of the veneering material rather than complete fractures. Materials and methods: 13 high-noble-alloy MC and 13 Y-TZP mo...

BACKGROUND The ferrule effect in root treated teeth requiring cast posts and cores has been shown to greatly improve fracture resistance. Studies have also shown that in the case of a cast post and core, the longer the ferrule, the greater the fracture resistance. However few studies have considered the effect of different ferrule designs on prefabricated post and composite core systems. AIM ...

The dynamic fracture behavior of layered architectures is experimentally studied. Specifically, crack penetration, trapping, and branching at an interface are examined. A newly introduced optical technique called Digital Gradient Sensing (DGS) that quantifies elasto-optic effects due to a non-uniform state of stress is extended to perform full-field measurements during the fracture event using ...

OBJECTIVES The purpose of this study was to propose a new classification system for open fractures developed by the Classification Committee of the Orthopaedic Trauma Association. SETTING Academic and Level I trauma center. PATIENTS/PARTICIPANTS Consecutive patients with open fractures. MAIN OUTCOME MEASUREMENTS Open fracture classification scale. RESULTS Evaluation of 34 factors identi...

OBJECTIVES Electron beam irradiation can be used to influence the mechanical properties of polymers. It was the aim of this study to investigate whether dental composites can benefit from irradiation in order to achieve increased fracture toughness, work of fracture, hardness or less wear. METHODS Two hundred rectangular specimens of five veneering composites were electron beam irradiated wit...

A Monteggia fracture is a fracture of the proximal ulna coupled with a radial head dislocation. Numerous classification systems have been developed to characterize these fractures. Bado classification is most commonly used. Bado type 1 Monteggia fractures are most common while type 3 & 4 are rare entities. In our case, after confirming the diagnosis as type 4 Bado Monteggia fracture dislocation...

Hydraulic stimulation in Enhanced Geothermal Systems is performed by injecting water at high pressure into low permeability, typically crystalline, rock. In most cases, the elevated pore pressure induces slip on preexisting fractures, resulting in an increase in permeability. This process involves interacting hydraulic, thermal, mechanical, and thermoelastic processes. It is complicated by the ...

background: nasal fracture is a common fracture due to trauma. gold standard method in diagnosis of nasal fracture is clinical examination and radiography is used in legal situation. recently, ultrasound is recommended as a noninvasive and simple method in diagnosis of nasal fracture. this study investigates the role of ultrasound in diagnosis of nasal fracture. methods: 126 cases with suspecte...

in recent years, the application of composite materials in aircraft and space vehicle structural components has become increasingly popular. preventing failure of composite structural systems has been an important issue in engineering design. due to the lack of through-the-thickness reinforcement, structures made from laminated composite materials and adhesively bonded joints are highly suscept...