Structural,elastic and thermodynamic properties under pressure and temperature effects of MgIn2S4 and CdIn2S4

A density functional-based method is used to investigate the structural, elastic and thermodynamic properties of the cubic spinel semiconductors MgIn₂S₄ and CdIn₂S₄ at different pressures and temperatures. Computed ground structural parameters are in good agreement with the available experimental data. Single-crystal elastic parameters are calculated for pressure up to 10 GPa and temperature up to 1200 K. The obtained elastic constants values satisfy the requirement of mechanical stability, indicating that MgIn₂S₄ and CdIn₂S₄ compounds could be stable in the investigated pressure range. Isotropic elastic parameters for ideal polycrystalline MgIn₂S₄ and CdIn₂S₄ aggregates are computed in the framework of the Voigt–Reuss–Hill approximation. Pressure and thermal effects on some macroscopic properties such as lattice constant, volume expansion coefficient and heat capacities are predicted using the quasi-harmonic Debye model in which the lattice vibrations are taken into account.     

Ab initio study of the structural,electronic, elastic and magnetic properties of Cu2GdIn,Ag2GdIn and Au2GdIn

We preformed first-principle calculations for the structural, electronic, elastic and magnetic properties of Cu₂GdIn, Ag₂GdIn and Au₂GdIn using the full-potential linearized augmented plane wave (FP-LAPW) scheme within the generalized gradient approximation by Wu and Cohen (GGA-WC), GGA+U, the local spin density approximation (LSDA) and LSDA+U. The lattice parameters, the bulk modulus and its pressure derivative and the elastic constants were determined. Also, we present the band structures and the densities of states. The electronic structures of the ferromagnetic configuration for Heusler compounds (X₂GdIn) have a metallic character. The magnetic moments were mostly contributed by the rare-earth Gd 4f ion.     

Réactivité des cinnamoyl-3 pyrones-2 vis à vis des amines primaires

The reaction of primary amines (methylamine, isopropylamine, benzylamine) in neutral medium, on 3-cinnamoyl-2-pyrones gave 7-amino-3,5-dioxo-l,6-octadienes 2 . The formation of these compounds is presumed to occur via nucleophilic attack of amines with a ring opening reaction followed by decarboxylation. Their structures were determined unambiguously by ¹H, ¹³C nmr spectroscopy, elemental analysis and mass spectrometry.     

Prediction study of the structural,elastic, electronic and optical properties of the antiperovskite BiNBa3

We use an ab initio full-potential linear muffin-tin orbital method within the local density approximation (LDA) to study the structural, elastic, electronic and optical properties of the antiperovskite BiNBa₃. The calculated lattice parameter is in good agreement with previous calculations. The elastic constants and their pressure dependence are calculated; we found a linear dependence of elastic stiffness on the pressure. We estimated the Debye temperature of this compound from the average sound velocity. We also present results of the effective masses for the electrons in the conduction band (CB) and the holes in the valence band (VB). To complete the fundamental characteristics of this compound we have analyzed the optical properties.     

Activated sulfahydantoin as Boc-glycine enolate equivalent: highly diastereoselective α-hydroxyalkylation and application to the synthesis of aldopentonate analogues

N-Boc-activated sulfahydantoin can be seen as glycine enolate equivalent. It appeared as a convenient starting material for the stereocontrolled preparation of threonine homologues through an alkaline syn aldolization involving a Boc migration. The methodology allowed the one-pot preparation of constrained analogues of polyoxamic acid.     

Phenomenological modeling and intensification of texturing/grinding-assisted solvent oil extraction: case of date seeds (Phoenix dactylifera L.)

Accelerated Solvent Extraction (ASE) and Dynamic Maceration (DM) were used with n-hexane to study the extraction of oil from date seed powders with different particle sizes. The intensification was studied with instant controlled pressure drop (DIC) as texturing pretreatment. DM yields increased from 4.57% to 10.49 ± 0.05% dry–dry basis (ddb) when particle size decreased from 1.4 to 0.2 mm. For coarsely grounded seed powder, ASE oil yields were 11.35 ± 0.05% ddb and 14.15% ddb for untreated and DIC date-seeds, respectively. Optimized DIC pretreatment allowed the smallest particle size powder to get 15.2 ± 0.05% ddb as ASE yields, while the 2-h DM yields increased from 4.67 to 11.62 ± 0.05% ddb for particle size decreased from 1.4 to 0.2 mm, respectively. Fundamental analysis of various powders was achieved through washing–diffusion phenomenological model. DIC texturing implied higher washing stage, with relative starting accessibility %δY_s of 70% against 55% for untreated particles. Consequently, the diffusion stage time was dramatically reduced, without great modification of effective diffusivity D_eff value. Therefore, DIC ground seeds greatly enhanced the mass transfer mechanism. The evaluation of starting accessibility δY_s enables to establish an empirical relationship between δY_s and particle diameter δY_s = f(D). Finally, DIC texturing did not imply any modification of the lipid profile.     

Potassium cerium(III) bis­(sulfate) monohydrate,KCe(SO4)2·H2O

The crystal structure of potassium cerium(III) bis­(sulfate) monohydrate, KCe(SO₄)₂·H₂O, is built up from irregular independent SO₄ tetra­hedra, CeO₉ polyhedra in the form of distorted tricapped trigonal prisms and K⁺ ions. Hydrogen bonding between the free water mol­ecule and sulfate groups supplement the ionic bonds characteristic of the rest of the structure.     

Investigations of the half-metallic behavior and the magnetic and thermodynamic properties of half-Heusler CoMnTe and RuMnTe compounds: A first-principles study

First-principles spin-polarized density functional theory （DFT） investigations of the structural, electronic, magnetic, and thermodynamics characteristics of the half-Heusler, CoMnTe and RuMnTe compounds are carried out. Calculations are accomplished within a state of the art full-potential （FP） linearized （L） augmented plane wave plus a local orbital （APW ＋ lo） computational approach framed within DFT. The generalized gradient approximation （GGA） parameterized by Perdew, Burke, and Ernzerhof （PBE） is implemented as an exchange correlation functional as a part of the total energy calculation. From the analysis of the calculated electronic band structure as well as the density of states for both compounds, a strong hybridization between d states of the higher valent transition metal （TM） atoms （Co, Ru） and lower valent TM atoms of （Mn） is observed. Furthermore, total and partial density of states （PDOS） of the ground state and the results of spin magnetic moments reveal that these compounds are both stable and ideal half-metallic ferromagnetic. The effects of the unit cell volume on the magnetic properties and half-metaliicity are crucial. It is worth noting that our computed results of the total spin magnetic moments, for CoMnTe equal to 4 ~tB and 3 p-B per unit cell for RuMnTe, nicely follow the rule μ2tot = Zt - 18. Using the quasi-harmonic Debye model, which considers the phononic effects, the effecs of pressure P and temperature T on the lattice parameter, bulk modulus, thermal expansion coefficient, Debye temperature, and heat capacity for these compounds are investigated for the first time.     

A New modelling strategy for phase-change heat transfer in turbulent interfacial two-phase flow

The paper presents a modelling strategy for phase-change heat transfer in turbulent interfacial two-phase flow. The computational framework is based on interface tracking ITM (level set approach), combined with large-scale prediction of turbulence, a new methodology known as Large-Eddy & Interface Simulation (LEIS), where super-grid scale turbulence and interfaces are directly solved, whereas the sub-scale parts are modelled. Because steady-state flow conditions are difficult to attain, recourse is made of the Very Large-Eddy Simulation (V-LES) instead of LES, where the flow-dependent cut-off filter is larger and independent from the grid. The computational approach is completed by a DNS-based interfacial phase-change heat transfer model built within the Surface Divergence (SD) theory. The original SD model is found to return better results when modified to account for scale separation, i.e. to segregate low-Re from high-Re number flow portions in the same flow. The model was first validated for an experiment involving a smooth to wavy turbulent, stratified steam-water flow in a 2D channel (Lim et al., 1984, Condensation measurement of horizontal concurrent steam-water flow, ASME J. Heat Transfer 106, 425–432.), revealing that the original SD model performs better for high interfacial shear rates. This screening phase also demonstrated that the most critical issue is the accurate prediction of the interfacial shear using ITM. The model was then applied successfully to predict condensing steam in the event of emergency core cooling in a Pressurized Water Reactor (PWR), where water is injected into the cold leg during a postulated loss-of-coolant-accident. The simulation results agree fairly well with the COSI (short for COndensation at Safety Injections) data (Janicot and Bestion, 1993, Condensation modelling for ECC injection, Nucl. Eng. Des. 145, 37–45).