severe plastic deformation (spd) methods were developed for producing of metals and alloys with ultrafine grained (ufg) microstructures having high strength. parallel tabular channel angular pressing (ptcap) as a noble severe plastic deformation (spd) method was used to produce ultrafine grained (ufg) and nanostructured cu-30%zn tubes. in this paper, the effect of ptcap process temperature on t...

Cell assembly sequences during learning are "replayed" during hippocampal ripples and contribute to the consolidation of episodic memories. However, neuronal sequences may also reflect preexisting dynamics. We report that sequences of place-cell firing in a novel environment are formed from a combination of the contributions of a rigid, predominantly fast-firing subset of pyramidal neurons with...

The shear-transformation-zone (STZ) theory of plastic deformation in glass-forming materials is reformulated in light of recent progress in understanding the roles played by the effective disorder temperature and entropy flow in nonequilibrium situations. A distinction between fast and slow internal-state variables reduces the theory to just two coupled equations of motion, one describing the p...

In most sheet-metal forming processes a large part of the deforming material exhibits stretch-dominant characteristics and the bending effect is found to exist only in a limited portion of the total deforming region. Thus the use of shell or continuum elements for the whole region is not economic. A selective membrane/shell (M/S) scheme is proposed which combines the layered degenerated shell e...

Drawbeads are applied in the deep drawing process to improve the control of the material flow during the forming operation. These drawbeads can be replaced by an equivalent drawbead in simulations of the deep drawing process. In this paper the implementation of an equivalent drawbead model in a finite element code is described. This equivalent drawbead takes not only the drawbead restraining fo...

This paper describes high temperature cyclic elastic-plastic testing of XN40F material for application to the life prediction of superplastic forming (SPF) tools. Cyclic plasticity material constitutive constants are identified from the high temperature tests across the range of 20C to 900C for representative predicted die conditions. These material constants are implemented within a transient,...

This work investigates the feasibility of using recycled high density polyethylene (rHDPE), recycled polypropylene (rPP) and old newsprint fiber (ONP) to manufacture fiber reinforced composites. The boards were made through air-forming and hot press. The effects of the fiber loading and coupling agent content on tensile, flexural, internal bond properties and water absorption and thickness swel...

The Finite Element analysis of the elastic-plastic behavior is of fundamental importance in automobile industry. To predict accurately the final geometry of the structure and the distribution of strain and stress, accurate integration of the constitutive laws over the strain path is essential. Our objective in this paper is to develop an effective and accurate stress integration scheme for the ...

In several practical cases, the ultimate ductile fracture strain determined with tensile test is accepted as a material plasticity measure 1 . In this case, the plasticity has to be defined as an ability of a material to accommodate high permanent strains until fracture appears where this strain reaches certain value called ultimate fracture strain p. The strain value until fracture depends not...

The use of peripheral blood progenitor cells (PBPC) to reconstitute hematopoiesis after high-dose chemoradiotherapy is now commonplace in the treatment of malignancies. Attempts to characterize these cells have concentrated primarily on their phenotype and their content of clonogenic colony-forming cells (CFC). We have used a plastic-adherent delta (P delta) assay system to evaluate the quantit...