Lattice and grain-boundary diffusion of phosphorus in commercially-pure copper

The diffusion rates of phosphorus in 3 batches of commercially-pure copper with different impurity content have been determined in the temperature range 574 to 1046° using the tracer-sectioning technique. There is clear evidence of grain-boundary diffusion occurring below 720°. The three activation energies and preexponential factors obtained for volume diffusion areQ _l = 1.43 eV, 1.44 eV, 1.43 eV;Dqi = 7.02 × 10^-3 cmVs, 7.98 x 10^-3 cm²/s, 4.38 × 10^-3 cm²/s. For grain-boundary diffusion the respective average values are Q_b = 0.70 eV and D_obδ≈ 4.2× 10^-7 cm3/s.     

Underwater Adhesives Produced by Chemically Induced Protein Aggregation

Barnacles convert hydrophilic proteins into an insoluble, yet aqueous, material that functions as a permanent underwater adhesive. Here, it is demonstrated that a common hydrophilic protein, bovine serum albumin, can be chemically triggered underwater to aggregate into a similar aqueous adhesive that mimics the formation of the natural adhesive. The combined action of multiple chemical denaturants initiates rapid gelation followed by further curing over time in artificial seawater. The adhesive strengths of this waterborne adhesive measured by lap shear are comparable to many bioinspired adhesives that use organic solvents and a high fraction of hydrophobic components. This approach establishes a bioinspired adhesive that can be deployed at practical scales in marine environments, produced sustainably, and sourced from low-cost materials.