Finite element analysis of plastic deformation in variable lead axisymmetric forward spiral extrusion

A modified axisymmetric forward spiral extrusion (AFSE) has been proposed recently to enhance the strain accumulation during the process. The new technique is called variable lead axisymmetric forward spiral extrusion (VLAFSE) that features a variable lead along the extrusion direction. To assess the effect of design modification on plastic deformation, a comprehensive study has been performed here using a 3D transient finite element (FE) model. The FE results established the shear deformation as the dominant mode of deformation which has been confirmed experimentally. The variable lead die extends strain accumulation in the radial and longitudinal directions over the entire grooved section of the die and eliminates the rigid body rotation which occurs in the case of a constant lead die, AFSE. A comparison of forming loads for VLAFSE and AFSE proved the advantages of the former design in the reduction of the forming load which is more pronounced under higher frictional coefficients. This finding proves that the efficiency of VLAFSE is higher than that of AFSE. Besides, the significant amount of accumulated shear strain in VLAFSE along with non-axisymmetric distribution of friction creates a surface feature in the processed sample called zipper effect that has been investigated. © 2012 Springer Science+Business Media New York.

A view to lead India : who are the candidates?

 India will go to the polls from April 5 to May 12 to choose between three party leaders for its next prime minister. The first is a seasoned politician and three-time chief minister, the Bharatiya Janata Party’s (BJP, or Indian People’s Party) Narendra Modi. The second is a youth icon without experience in governance, Indian National Congress’ Rahul Gandhi. Finally, there is a former bureaucrat and utopian visionary who resigned from the post of chief minister, Arvind Kejriwal.

Substantial reductions in the number of diabetic ketoacidosis and severe hypoglycaemia episodes requiring emergency treatment lead to reduced costs after structured education in adults with Type 1 diabetes

To determine the impact of structured education promoting flexible intensive insulin therapy on rates of diabetic ketoacidosis, and the costs associated with emergency treatment for severe hypoglycaemia and ketoacidosis in adults with Type 1 diabetes.

A biomimetic sensor for the detection of lead in water.

The monitoring of lead (II) ions (Pb(2+)) in water is essential for both human health and the environment. Herein, a simple yet innovative biosensor for Pb(2+) detection is presented. The sensor is developed by the self-assembly of gold nanoparticles (GNPs) core-satellite structure using naturally occurring tripeptide glutathione (GSH) as linker. The addition of Pb(2+) caused a red-to-blue color change and the localized surface plasmon resonance (LSPR) band was shifted to ca. 650nm. The limit of detection (LOD) is found to be 47.6nM (9.9ppb) by UV-vis spectroscopy with high selectivity against other heavy metals. This method offers a new strategy for heavy metal detection using functionalized GNPs.

Improving chlamydia knowledge should lead to increased chlamydia testing among Australian general practitioners: a cross-sectional study of chlamydia testing uptake in general practice

Female general practitioners (GPs) have higher chlamydia testing rates than male GPs, yet it is unclear whether this is due to lack of knowledge among male GPs or because female GPs consult and test more female patients.