51 research outputs found

    Valorization of Moroccan olive stones by using it in particleboard panels

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    The main objective of this work was to find new applications to valorize olive stones (endocarp and seed). In order to improve knowledge on olive stones, the phenolic compounds concentration of three varieties of Moroccan olive trees: Moroccan Picholine, Menara and Haouzian were studied. Olive stones of three varieties were characterized by Fourier Transform Mid Infrared Spectroscopy (FT-MIR). Total phenolic compounds are quantified after solid-liquid extraction by an assay of Folin-Ciocalteu. Moroccan Picholine stones (11.32 mg GAE/g DM) have a higher content of total phenolic compounds than Haouzia stones (4.55 mg GAE/g DM) and Menara stones (3.56 mg GAE/g DM). Thermogravimetric analysis indicates that up to 195 degrees C; there is no degradation of the stones. The biocide performance on agar-agar was tested with decay fungi. Biodegradation studies show that the most interesting results are obtained with Moroccan Picholine stones. The presence of Moroccan Picholine in a particleboard panels improves the total resistance of the particleboard panels against both Coriolus versicolor and Coniophora puteana rot fungi

    A multidisciplinary study of chemico-physical properties of different classes of 2-aryl-5(or 6)-nitrobenzimidazoles: NMR, electrochemical behavior, ESR, and DFT calculations

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    Continuing in our researches on the syntheses, reactivity, pharmacological/biological activities of heterocyclic compounds containing one or more nitrogen atoms we have examined some chemico-physical properties (1H and 13C NMR, electrochemical behavior, and ESR) of three series of 2-aryl-5(or 6)-nitrobenzimidazoles (1–3) variously substituted in the 2-aryl ring. The electrochemical behavior of the nitro group on the benzimidazole ring has been studied by cyclic voltammetry. This has allowed to point out both the reversibility, the formal potential, and the number of electrons involved in the electrochemical processes, and to evaluate the effect of the substituents present on the aryl ring. The data collected have been able to furnish a complete picture of electronic distribution and have been supported by DFT calculations

    Thin-shell wormholes from charged black holes in generalized dilaton-axion gravity

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    This paper discusses a new type of thin-shell wormhole constructed by applying the cut-and-paste technique to two copies of a charged black hole in generalized dilaton-axion gravity, which was inspired by low-energy string theory. After analyzing various aspects of this thin-shell wormhole, we discuss its stability to linearized spherically symmetric perturbations.Comment: Minor changes, 6 pages, 4 figures. Accepted for publication in Gen. Rel. Gra

    Radial stability analysis of the continuous pressure gravastar

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    Radial stability of the continuous pressure gravastar is studied using the conventional Chandrasekhar method. The equation of state for the static gravastar solutions is derived and Einstein equations for small perturbations around the equilibrium are solved as an eigenvalue problem for radial pulsations. Within the model there exist a set of parameters leading to a stable fundamental mode, thus proving radial stability of the continuous pressure gravastar. It is also shown that the central energy density possesses an extremum in rho_c(R) curve which represents a splitting point between stable and unstable gravastar configurations. As such the rho_c(R) curve for the gravastar mimics the famous M(R) curve for a polytrope. Together with the former axial stability calculations this work completes the stability problem of the continuous pressure gravastar.Comment: 17 pages, 5 figures, References corrected, minor changes wrt v1, matches published versio

    Thin-shell wormholes from regular charged black holes

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    We investigate a new thin-shell wormhole constructed by surgically grafting two regular charged black holes arising from the action using nonlinear electrodynamics coupled to general relativity. The stress-energy components within the shell violate the null and weak energy conditions but obey the strong energy condition. We study the stability in two ways: (i) taking a specific equation of state at the throat and (ii) analyzing the stability to linearized spherically symmetric perturbations about a static equilibrium solution. Various other aspects of this thin-shell wormhole are also analyzed.Comment: 8 pages and 19 figure
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