Fermat-linked relations for the Boubaker polynomial sequences via Riordan matrices analysis

The Boubaker polynomials are investigated in this paper. Using Riordan matrices analysis, a sequence of relations outlining the relations with Chebyshev and Fermat polynomials have been obtained. The obtained expressions are a meaningful supply to recent applied physics studies using the Boubaker polynomials expansion scheme (BPES).Comment: 12 pages, LaTe

Structural and Optoelectronic Properties of In-Zn-S sprayed Layers

In this work, In-Zn-S thin layers were prepared using the spray pyrolysis technique on glass substrates at 320°C. The molar ratio between zinc and indium $x=[Zn^{2+}]//[In^{3+}]$ was varied in 0-0.4 domain whereas $[S^{2-}]//[In^{3+}]$ one was taken constant equal to 2. The atomic composition was carried out with the atomic absorption. The structural study of all layers via X-ray diffraction and atomic force microscopy shows that the layer, obtained using x=0 is formed by binary material $In_2S_3$ with a principal orientation along (400). When the composition increases the same study depicts the presence of other materials such as ZnO, ZnS, and $ZnIn_2S_4$. On the contrary, for x=0.4, the film is mainly formed by the ternary compound $ZnIn_2S_4$ which crystallizes in cubic phase. Moreover, the optical analysis via the transmittance, reflectance as well as the photocurrent reveals that the band gap energy $E_g$ increases slightly as a function of the x composition ($E_g$ varies from 2.6 to 2.9 eV)

Physicochemical and sensory characteristics of virgin olive oils in relation to cultivar, extraction system and storage conditions

This research was carried out to evaluate the effects of variety, extraction systemand storage conditions such as packaging type and temperature variation on the quality of virgin olive oil. Several parameters were studied, namely, quality indices, polyphenols, tocopherols, volatile compounds and sensory properties. Thus, two olive varieties Chemlali (Tunisia) and Coratina (Italy) were selected. The olive oils were extracted by different industrial processes (super press, dual and triple phase decanter) then stored in the established conditions (ambient and refrigerator temperature) in the following packaging materials: clear and dark glass bottles and metal bottles. The oils were analyzed before and after being stored for 9 months. Principal Component Analysis and Graphical Modeling were applied to fully explore the influence of the studied factors. Results revealed that among samples, oils from Coratina cultivar were the richest in γ-tocopherol while Chemlali oils contained the highest amount of Δ-tocopherol. Quality indices namely K232 and K270 values were mainly influenced by the storage date and packaging material.Meanwhile, free acidity and peroxide value were mainly influenced by the extraction system. Concerning tocopherols, α-tocopherol content was mainly influenced by the packaging material, β-tocopherol was mainly affected by the storage date, for γ-tocopherol content the main influencing factor was the cultivar whereas for Δ-tocopherol the main influencing factor was the extraction system. Regarding volatile compounds their amounts were influenced mainly by the storage date, thatwas influenced by the packaging material, where a considerable decrease was observed after storage which was reflected by the change of sensory characteristics of stored oils: loss of positive attributes fruitiness, bitterness and pungency and onset of defects which were mainly influenced by the storage date (fruity and bitter attributes), packaging material (pungent, rancid and fusty attributes) and extraction system (musty attribute

Effects of Olive Trees Age on the Minor Components of Oueslati Virgin Olive Oils Produced from Olives Harvested at Different Ripening Degrees

Phenolics, volatiles, squalene, tocopherols, and fatty acids of virgin olive oils (VOO) from adult and young olive trees of the Oueslati variety, typically cultivated in the Center of Tunisia, were analyzed at three different harvesting periods. Significant differences in contents of saturated fatty acids (p\ua0<\ua00.05), squalene (p\ua0<\ua00.05), alpha-tocopherol and total tocopherol (p\ua0<\ua00.02) and oxidized form of decarboxymethyl oleuropein aglycon (p\ua0<\ua00.05) were seen between VOO from adult and young trees during maturation. Moreover, the volatile profiles of VOO from adult and young trees showed significant differences in the amounts of hexanal, 1-penten-3-ol (p\ua0<\ua00.05), (Z)-3-hexenal and (Z)-2-penten-1-ol (p\ua0<\ua00.01). Principal component analysis showed that olives from adult trees should be harvested at the cherry stage of maturation to obtain a satisfactory level of oil quality, while olives from young trees should be harvested at the black maturation stage