Silkworm (Bombyx mori) cocoon vs. wild cocoon multi-layer structure and performance characterization

Abstract

As protective shells for their biological functions against environmental damage and attack by natural predators, the silkworm (Bombyx mori) cocoon and its wild partner have distinctive multi-layer structures, which are systematically studied in this paper by the SEM, the thermogravimetric analyzer, and the Fourier transform infrared spectroscopy. Their mechanical properties are also investigated for the whole hierarchy and each cascade as well. In order to better demonstrate the superior survivability of cocoons in harsh environments, air permeability and moisture vapor transmission rate of the silkworm cocoon are tested. The results show the silkworm cocoons have excellent air permeability and moisture vapor transmission rate. A better understanding of different cocoons' bio-functions will be of particular importance to design thermal textiles and provide better comfort and safety for clothing in future.

Fractal calculus for refrigerated transportation of perishable foods: Energy consumption and energy saving

“…Snow and cocoon have good thermal insulation property [7,8] due to their hierarchical structure, wools and pole bear hairs also have good thermal property due to their special geometric structure with fractal dimension of 1.618 [9][10][11][12][13][14][15][16], all those natural phenomena can be used for biomimetic design of freezers in future, and the fractal theory and fractal calculus [5,6] provide us with good mathematical tools to theoretical analysis of the thermal properties of the freezers.…”

“…We use one-dimensional fractal model to describe the heat conduction of the freezer, which is considered as a fractal-like porous structure. The heat equation for the freezer can be expressed as [3][4][5][6][7][8]…”

New promises and future challenges of fractal calculus: From two-scale thermodynamics to fractal variational principle

“…In literature, eq. 29was called as He's fractional derivative [31][32][33][34][35][36][37][38][39][40][41][42], and it has been applied to biomechanics [38], nanoscale thermodynamics [39], Zakharov-Kuznetsov equation [31], KP-BBM equation [32], solitary theory [33], non-linear vibration [34], coast protection [35,36], high-order sub-diffusion broblem [37], fractional optimal control problems [38], drug release [39][40][41], and biomaterials [42].…”

When mathematics meets thermal science: The simpler is the better

“…The slow-fast law(extremely slow-extremely fast law) implies that a slow change at initial stage must lead to a fast change at terminal stage, and vice versa; an extremely fast change at initial stage must result in an extremely slow change at the terminal stage, examples of the slow-fast law are thermal properties of cocoon [11], polar bear hairs [8,9], and snow ball [1]. A sudden earthquake, a sudden avalanche and a sudden gas explosion arise in, respectively, an extremely slow change of tectonic plate's motion, an extremely slow motion of the snow drift, and an extremely slow concentration change of a flammable gas.…”