The effect of freeze-drying and gamma irradiation at 0.5, 1, and 2 kGy on the physicochemical composition (moisture, fat, ash, mineral, and chlorophyll contents), microstructure, total phenolic content, and antioxidant capacity of stevia leaves was investigated in the present study. The results obtained indicated that freeze-drying and gamma irradiation treatments caused significant reduction ( p  ≤ 0.05) of moisture and fat contents in comparison with those of commercial leaves, while ash content was not significantly affected. Mineral composition was analysed. Among the analysed elements, potassium and iron levels were higher in the freeze-dried and irradiated samples, respectively. The microstructure was analysed using a scanning electron microscope. Micrographs revealed that a higher porous size structure was obtained by freeze-drying, and degradation of cell wall structure was more clearly visualized by irradiation at 2 kGy. However, the main functional groups were stable as confirmed by Fourier transform infrared spectroscopy analysis. The effects on chlorophyll content, phenolic profile, and antioxidant properties were evaluated before and after ten months of storage. In terms of chlorophyll contents, the freeze-dried leaves exhibited the highest content. Chlorophylls a and b decreased when storage progressed for freeze-dried leaves as well as for gamma-irradiated leaves. Both preservation methods gave significant advantages in increasing the total phenolic content and DPPH scavenging activity. Moreover, a significant increase of bioactive compounds and antioxidant activity was observed as the gamma irradiation dose increased. In addition, the storage time increased the amounts of polyphenols and DPPH scavenging activity. After 10 months of storage, gamma-irradiated leaves had the highest total phenolic content as well as the DPPH scavenging activity followed by freeze-dried leaves. The results indicate that freeze-drying and gamma irradiation at the studied doses could be effective postharvest methods for preservation of stevia leaf quality.

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The need for construction sand needs to increase due to the increase in population. The use of dunes and coastal sand disfigures shorelines and the consequences are alarming. It is therefore necessary to consider replacing these resources with other more ecological ones. Hence the purpose of this article. In this paper, we study the correct formulation of concrete using dredged sand, respecting the standards, and analyze the impact of this new material on the physical and mechanical characteristics of concrete. This article aims to evaluate the effects of 9 formulations, used as substitutes for ordinary sand, on the physico-chemical and mechanical properties. The experimental results have shown that the dredged sand affects the properties of the concrete, but respecting the standards in force. This mode of incorporation also has an environmental advantage over the substitution of concrete for dredged sand, as it reduces the disfigurement of the coasts. The paper studies dredge sands from two regions namely Azemour and Mehdia.

Because of the repeated passage of trains, anomalies are created inside the rails in the form of cracks of different shapes and position. These are due essentially to the wheel – rail contact. They present a hazard causing at the final stage rail failure, train derailment and accidents. Detecting track anomalies has become a major issue for the entire rail industry around the world. This paper focuses on the degradation of rails in urban railways in terms of cracks. The purpose is to develop an approach to detect and predict rail breaks, which will optimize maintenance task. Infrared thermography was used in order to characterise the effect of a defect on the acquired thermogram. Different defects were considered by varying their size, depth and inclination angle with respect to the rail surface.