A Comparative Study on the Microstructures, Mineral Content, and Mechanical Properties of Non-Avian Reptilian Eggshells.

We analyze 214 freshly laid eggs belonging to 16 species across three orders of Class Reptilia. Using mechanical compression tests, we measure each egg's absolute stiffness (, unit: N m) and relative stiffness ( number). The effective Young's modulus, , was obtained by combining experimental and numerical methods.

Functional connections between bird eggshell stiffness and nest characteristics through risk of egg collision in nests.

Eggs and nests are two critical traits for the ecological success of birds. Their functional interactions, however, remain unclear. Here, we examined the functional connections between egg stiffness and nest attachment, site and structure for 1350 avian species.

Elastic Moduli of Avian Eggshell.

We analyze 700 freshly-laid eggs from 58 species (22 families and 13 orders) across three orders of magnitude in egg mass. We study the elastic moduli using three metrics: (i) effective Young's modulus, , by a combined experimental and numerical method; (ii) elastic modulus, , by nanoindentation, and (iii) theoretical Young's modulus, . We measure the mineral content by acid-base titration, and crystallographic characteristics by electron backscatter diffraction (EBSD), on representative species.

Correction to 'Cracking failure of curved hollow tree trunks'.

[This corrects the article DOI: 10.1098/rsos.200203.

Cracking failure of curved hollow tree trunks.

Understanding the failure modes of curved hollow tree trunks is essential from both safety and conservation perspectives. Despite extensive research, the underlying mechanism that determines the cracking failure of curved hollow tree trunks remains unclear due to the lack of theoretical analysis that considers both the initial curvature and orthotropic material properties. Here we derive new mathematical expressions for predicting the bending moment, , at which the cracking failure occurs.