Sorption/desorption study of strontium on Ain Oussera soils around the Es-Salam reactor facility

Four types of undisturbed soils around the Es-Salam reactor (Algeria) were used to evaluate the sorption behavior of strontium. The batch study was carried out under different experimental conditions. The kinetics were well fited by pseudosecond order model. Soils’s activation energies were 12.37, 14.76, 15.5 and 16.17 kJ mol⁻¹, corresponding to ion-exchange-type sorption. Sorption was exothermic (ΔH° < 0), spontaneous (ΔG° < 0) and favorable at low temperature. Competing cations, particularly Ca²⁺ reduce the Sr adsorption. Desorption reaction showed a higher value of Sr in the easily extractible phase indicating a relative availability of the element.

     

Chemical elements of Algerian Mentha spicata L. used in the treatment of digestive system disorders by employing instrumental neutron activation analysis technique

Journal of Radioanalytical and Nuclear Chemistry - The objectives of this research were to study the elemental concentrations of Mentha spicata L., using a sensitive nuclear analytical technique...     

Band gap and band offsets of GaNAsBi lattice matched to GaAs substrate

In this paper, we calculate the band gap and the band discontinuities of a GaN _y AsBi _x structure lattice matched to GaAs substrate using the conduction and the valence band anticrossing models at the same time. The results obtained show a good agreement with experiment. The nitrogen and the bismuth concentrations leading to a wavelength emission of 1.55 μm have been determined (x = 3.5%, y = 2%). This structure shows a good electron confinement resulting in a high characteristic temperature.     

Novel palladium nanoparticles supported on mesoporous natural phosphate: Catalytic ability for the preparation of aromatic hydrocarbons from natural terpenes

Various ratios of palladium nanoparticles supported on mesoporous natural phosphate (Pd@NP) were prepared using the wetness impregnation method. The prepared catalysts were characterized by IR, XRD, CV, SEM, EDX, XRF, TEM and BET analysis. The reduction and preparation of the palladium nanoparticles afford a crystallite size of 10.88 nm. The performance of the synthesized catalyst was investigated in the solvent-free dehydroaromatization of α-, β- and γ-himachalene mixture from Cedrus atlantica oil as a model substrate. In order to achieve an efficient and selective catalysis, the catalytic dehydroaromatization of various terpenes such as limonene, limonaketone, carvone, carveol and perillyl alcohol was studied. The Pd@NP catalyst performed a high catalytic activity, selectivity and recyclability in the terpenes dehydroaromatization reaction.     

On the Reactivity of (−)‐(R)‐Carvone and (−)‐4aα,7α,7aβ‐Nepetalactone: Synthesis of New Heterocycles

The 1,3‐dipolar cycloaddition of 4‐chlorobenzonitrile oxide to the unsaturated system of (?)‐(R)‐carvone occurred exclusively at C(8) to give a new isoxazoline derivative. This derivative reacts with NH₂OH to yield a new heterocycle, observed for the first time. On the other hand, the addition of 4‐chlorobenzonitrile oxide to the unsaturated lactone (?)‐4aα,7α,7aβ‐nepetalactone gave, in a good yield, also a new heterocycle, again obtained for the first time. The terpenoid (?)‐(R)‐carvone and iridoid (?)‐4aα,7α,7aβ‐nepetalactone were isolated from Moroccan species Mentha viridis (L.) and Nepeta tuberosa (L.), respectively. The new heterocycles obtained were identified by combination of chromatographic and spectroscopic methods.     

Study of the usability of sinusoidal function heat flux based on enthalpy-porosity technique for PCM-related applications

Journal of Thermal Analysis and Calorimetry - The present study summarizes a two-dimensional (2D) numerical simulation of a phase change material (PCM) melting/solidification processes in a square...     

Identities of arithmetic type between values of the theta function associated to a lattice in ℝ d and its derivatives

In this paper, we introduce a notion of similarly self dual lattice in a d-dimensional Euclidean space and a classical Jacobi theta function is associated to such a lattice. We establish identities of arithmetic type between values of this theta function and its successive derivatives. This work can be related to the spectral theory of the Landau operators.      

Experimental determination of the helicoidal electric field inside a twisted mesophase, in the selective reflection band

We consider the interface between a twisted birefringent mesophase and an isotropic medium. In the selective reflection band, when illuminated at normal incidence, the interface creates a coupling between the located dielectric reflection and the spread selective reflection. This coupling enables experimental measurement of the standing electric field orientation inside the liquid crystal.