T he widespread use of pins to provide retention for amalgam restorations began with Markley’s’ description of cemented stainless steel pins. In 1966 the selfthreading pin technique was introduced.2 Unlike cemented pins, which rely on cement to hold them in place, self-threading pins are larger than the pinhole and are threaded into it. The cutting action of the threads retains self-threading p...

It is common for subsurface flow to transition between porous and fractured media. Two examples include vertical infiltration of precipitation through a permeable soil overlying a fractured bedrock, and horizontal ground water flow through a combination of porous and fractured geologic units. A reduction in flow or flow impedance may occur across these interfaces caused by head losses associate...

Diaphyseal fractures of the femur and tibia in adults are mostly treated surgically, usually by means of intramedullary locked-nail osteosynthesis. Some comminuted and/or highly deviated shaft fractures may present a veritable technical challenge. Fracture (or orthopedic) tables, which enable vertical, horizontal and rotational instrumental stabilization of the limb, greatly facilitate reductio...

In recent years, infill horizontal well technology has been used to develop oil and gas in the remaining areas of unconventional low-permeability reservoirs. However, initial fractures parent wells will affect hydraulic formed by fracturing infilling wells. The interaction mechanisms between artificial are still unclear. Combined with boundary element method maximum circumferential tensile stre...

THE ATTRITIOUS AND FRACTURE WEAR OF GRINDING WHEELS by Stephen Malkin Submitted to the Department of Mechanical Engineering February 1968, in partial fulfillment of the requirements for the degree of Doctor of Science A detailed investigation is made of the nature and extent-of grinding wheel wear in finish grinding. The wear is broadly classified as either attritious or fracture wear. Attritio...

Duplex stainless steel has excellent strength and corrosion resistance, it is widely used such, for example, in plant applications. The microduplex structure affects not only the physical properties but also deformation behavior. fracture considered to be caused by peeling duplex interface been confirmed various experiments parts manufacturing factories, there are few detailed references morpho...

This case report aims to describe a long-term follow-up after the immediate treatment of multiple dental injuries. A 15-year-old female patient was admitted private clinic 30 minutes an accident at school. After clinical and radiographic examinations, tooth 21 diagnosed with enamel fracture horizontal root fracture, 22 lateral luxation, teeth 12, 11, 23 were subluxation. Teeth presented pulp ne...

UNLABELLED Stabilization of fractures by external fixator is based on the mechanical connecting of the pins, screwed into the proximal and distal bone fragment. Site of fracture is left without any foreign materials, which is essential for prevention of infections. Aim of this work is to compare stability of constructs bone model-external fixators of different types (Ortofix, Mitković, Charnele...

One of the important hurdles in horizontal well stimulation is the generation of hydraulic fractures (HFs) from all perforation clusters within a given stage despite the challenges posed by stress shadowing and reservoir variability. In this paper we use a newly-developed, fully coupled, parallel-planar 3D HF model to investigate the potential to minimize the negative impact of stress shadowing...

Multi-stage, multi-cluster fracturing in horizontal wells is widely used as one of the most effective methods for unconventional reservoir transformation. This study based on extended finite element method and establishes a multi-hydraulic propagation model that couples rock damage, stress, fluid flow, influence stress difference cluster spacing fracture quantitatively analyzed. The simulation ...