We introduce numerical methods and algorithms to estimate the main parameters of fractal-like particle aggregates from their optical structure factor (i.e. light scattering diagrams). The first algorithm is based on a direct and simple method, but its applicability is limited to aggregates with large size parameter and intermediate fractal dimension. The second algorithm requires to build calibration curves based on accurate particle agglomeration and particle light scattering models. It allows analyzing the optical structure factor of much smaller aggregates, regardless of their fractal dimension and the size of the single particles. Therefore, this algorithm as well as the introduction of a criterial curve to detect the different scattering regimes, are thought to be powerful tools to perform reliable and reproducible analysis.
The aim of this paper is to compare some geometric parameters and deflections of a sandwich meta-structure with its classic, three-layer counterpart. Both structures are composed of the same materials and have the same external dimensions and mass, but their middle layers (cores) are different. The core of the sandwich meta-structure is a new spatial structure itself, consisting of there-layer bars. The core of the classic sandwich structure is a layer of the continuum. To make the comparison more general and convincing, three geometrical parameters, i.e., ratio of interfacial contact (Ric), interlayer bonding factor (Ibf) and coefficient of impact sensitivity (Cis), were introduced and applied. Deflections of the structures, simply supported at the edges and loaded in the mid-span by a static force, have been measured and are presented in the paper. Potential advantages of the new meta-structure are briefly outlined.