This study aimed to describe the behavior of ginger, and to predict its water content, during artificial drying under four temperatures (60 oC, 80 oC, 100 oC, 120 oC). Experiments were carried out on ginger using a DRY-Line type oven. The obtained data was fitted using 4 semi-empirical thin layer drying models. Among the semi-empirical models considered, the diffusion approach model was chosen as the most appropriate model to describe the behavior of ginger. For the different temperatures, he presented respectively the coefficients (r) of 0.9970; 0.9974; 0.9949 and 0.9942; the coefficients Chi-square (χ²) of 4.0306 X 10-6, 3.7015 X 10-7; 1.6387 X 10-7 and 1.3637 X 10-6 and Root Mean Square Errors (RMSE) of 3.5851 X 10-4; 1.1415 X 10-4; 9.2226 X 10-5 and 2.6604 X 10-4 for the four temperatures. The diffusion coefficient varies from 9.585 X 10-9 to 3.466 X 10-8 m2/s and strongly depends on the drying temperature. The activation energy is estimated at 24.188 kJ/mol.

This work aimed to determine the voltammetric charges at the electrode / electrolytic solution interface of the IrO2, PtOx and IrO2-PtOx electrodes. The scanning electron microscope characterization (SEM) showed the presence of the IrO2 and PtOx coating deposited on titanium supports. Also, this characterization revealed that the surface of the prepared electrodes is porous and rough. The cyclic voltammetry measurements allowed to show that the voltammetric charge is high at low scan rates. This result is due to the accessibility of the internal and external surfaces of prepared electrodes by electrolytic solution. In contrast, for the high scan rates, only the external (geometric) surface is in touch with the electrolyte. The voltammetric charge decreases when the pH of electrolyte increases. Regardless of the electrolytic solution the voltammetric charges increases in the order: PtOx < IrO2 < PtOx-IrO2. In the absence of free protons (KClO4 and KOH medium), the electrolyte diffuses inside the pores of the deposit regardless of its composition. Thus, all our electrodes have a large number of internal active sites. This study revealed that the processes which take place at the electrode / electrolyte interface are complex. These processes depend on several factors including the composition of the deposit, the proton concentration, etc. The linear correlations between the total voltammetric charge (q*tot) and the total capacitance (Ctot) show that they can be used to represent the extension of the electrochemically active surface.