In this paper, an analytical method for noncircular shape extrusion is presented. Using this method, non-linear deformation field can be described with Hermit cubic spline which is prescribed by the boundary conditions of the die at its entryand exit. The upper bound method has been used to obtain optimum coefficient of the tangential boundary conditions. The results show that the optimum tange...

In this paper, a generalized expression for the flow field in axisymmetric extrusion process is suggested to be valid for any dies and the boundary shapes of the plastic deformation zone. The general power terms are derived and the extrusion force is calculated by applying upper bound technique for a streamlined die shape and exponential functions for shear boundaries. It is shown that assuming...

Metal forming operations such as rolling, extrusion, and drawing offer many opportunities for operations improvement through better process understanding and improved planning practices. This paper addresses short and medium term planning issues in sheet, plate, and tube manufacturing operations. First, v^e identify certain distinctive characteristics-the inherent process flexibility, close int...

BACKGROUND Rupture of the medial canthal ligament can be caused by many events. It remains a challenge to rebuild the drainage system and restore the function. The aim of this study was to evaluate the clinical efficacy of medial canthoplasty combined with conjunctivodacryocystorhinostomy (CDCR) in patients with medial telecanthal deformities and lacrimal drainage system damage. METHODS Twent...

A method has been developed which allows a length of electrically excitable squid axon to be internally dialyzed against a continuously flowing solution of defined composition. Tests showed that diffusional exchange of small molecules in the axoplasm surrounding the dialysis tube occurred with a half-time of 2-5 min, and that protein does not cross the wall of the dialysis tube. The composition...

Vortex extrusion (VE) is a severe plastic deformation technique which is based on the synergies between high strain accumulation and high hydrostatic pressure. Such a high amount of pressure, places a mandate to seek the method for investigation of the load under processing conditions. For this, kinematically admissible velocity field and upper bound terms based on Bezier formulation are develo...

Eustachian tube dysfunction (ETD) is estimated to affect approximately 1% of the UK population. ETD and subsequent inadequate middle ear ventilation have been implicated in the pathogenesis of otological diseases including otitis media with effusion (OME), retraction pockets, tympanic membrane (TM) perforation and cholesteatoma. Patients may present with vague, non-specific symptoms including a...

BACKGROUND Irrigation of the root canal system is an essential step in the endodontic treatment. The aim of this article is to introduce continuous apical negative-pressure ultrasonic irrigation (CANUI), a new irrigation concept, and compare the characteristics of this new technique with current devices for activating the irrigant. MATERIAL AND METHODS CANUI is designed for cleaning and disin...

for many years, gutta-percha has been the root canal filling material of choice. chloroform is one of the most efficient solvents widely used for gutta-percha removal in retreatment cases, despite being toxic and carcinogenic. the present case report discusses a chloroform extrusion through an existing perforation to the surrounding periodontal ligament space and subsequent necrosis in supporti...

The main objective of this paper is to study the effect of extrusion parameters (extrusion stresses and temperature) and die geometry, i.e. extrusion radius, on the extruded aluminum quality using FEM Simulation Technique. For this purpose, the general FEA Software ABAQUS was used to set up the finite element model of the warm aluminum extrusion in two dimensions (2D). Aluminum alloy Al-2014 wa...