Monday, December 05, 2016
It’s an exciting day for one of the school’s PhD students, and somebody who has appeared on the blog a couple of times already. Rhys Archer appeared in the #MondayMaterials series and also wrote a post for us about her success in the ‘I’m An Engineer, Get Me out of Here’...
Monday, December 12, 2016
Title - Deformation of Ultra-Fine Grained Polycrystals The density of geometrically necessary dislocations (GND) obtained from the lattice curvature was studied in commercially pure copper up to extreme large strains (von Mises strain of 63). Its evolution shows an increase to a maximum at a strain of about 2, then decreases until reaching the stationary limiting stage of grain refinement at a von Mises strain of about 14. At the same time, the total dislocation density is also decreasing. It is shown that the variation in the GND density correlates with the difference between the correlated (first neighbor grains) and the non-correlated (random neighbor) misorientation angle distributions. The low quantity of GND at extreme large strains is a consequence of the near Taylor-type homogeneous behavior of the polycrystalline ultrafine-grained structure.
Wednesday, January 18, 2017
Professor Melik Demirel, Director of the Center for Research on Advanced Fiber Technologies (CRAFT) at Penn State University is visiting Manchester to talk about Programmable 2-Dimensional Molecular Composites on 18th January 2017. Recent advances in nanotechnology of two-dimensional (2D) materials combined with parallel improvements in biotechnology and synthetic biology demonstrated that more complex composites materials with properties engineered precisely to optimize performance could be achieved. We propose to create functional programmable materials with user defined physical properties from composites of 2D materials (e.g., graphene oxide and titanium carbide) and polymeric proteins. Our approach is based on an ultra-fast microscopy technique to screen molecular morphology of polymeric proteins. These proteins have several advantages as programmablematerials: (i) their chain length, sequence, and stereochemistry can be easily controlled, (ii) their molecular structure and morphology is well-defined, (iii) they provide a variety of functional chemistries for conjugation to 2D materials, and (iv) they can be designed to exhibit a variety of physical properties. The amino-acid sequence of the protein layers can be controlled to prescribe the alignment of 2D materials that will form the substrate of our composites. The variability of the amino-acid sequences in the polymeric proteins, which will dictate the degree of crystallinity and alignment of the protein layers, are used to control the interactions at the 2D material/protein interface, ultimately dictating the functional physical properties (e.g., electrical resistivity and thermal conductivity) of novel materials and devices.