Validation of gravimetry for high-accuracy analysis of uranium

Journal of Radioanalytical and Nuclear Chemistry - Gravimetry after calcination is an assay method for determining the quantity of a given element from the mass measurement. This method, adapted...     

N,N′-Ethylenebisstearamide Additive in Intravaginal Drug Delivery Device Determined by NP-LC with ELSD

A new method for N,N′-ethylenebisstearamide analysis was developed and validated in NP-LC with evaporative light scattering detection for EBS content in drug delivery device. Chromatographic conditions were silica column 250 × 3 mm at 45 °C with 94:6 CHCl₃/ethanol at 0.5 mL min^?1. The retention time of N,N′-ethylenebisstearamide was 4.35 min. The method was fully validated by applying a novel strategy using accuracy profiles. The EBS content in the progesterone device was established after administration in animal which proved that such additives did not migrate into the animal.     

Complex dynamics in 2-species predator-prey systems

In this work, we consider some dynamical properties and specific contactbifurcations of a discrete-time predator-prey system having inverseswith vanishing denominator. The dynamics is investigated by usingconcepts of focal points, prefocal curves and bifurcation theory.The system undergoes flip bifurcation and Neimark-Sacker bifurcation.Numerical simulations are presented not only to illustrate our resultswith the theoretical analysis, but also to confirm further the complexityof the dynamical behaviors as extinction, persistence and permanence.     

Potassium Fluoride on Alumina: One-Pot Synthesis of N-Allyl Trichloroacetamides by Cascade Condensation-Sigmatropic Rearrangement

Allyl alcohols adsorbed on Al₂O₃-KF at room temperature reacted with trichloroacetonitrile and gave rearranged trichloroacetamides at room temperature, in one pot reaction.     

Highly sensitive modified glassy carbon sensor based on TDAN for nitrate detection in real water

Glassy carbon electrodes modified with a plasticized PVC membrane including tetradodecyl ammonium nitrate (TDAN) and two different plasticizers [bis(2-etheylhexyl) sebacate (DOS) and dibutyl phthalate (DBP)]. TDAN is a quaternary ammonium salt, used in nitrate-selective field-effect transistor membrane, and it is applied as an ionophore for sensor development. Membranes were prepared as sensing matrix for nitrate detection through the intensity of its reduction peak using cyclic voltammetry. Under optimum conditions, the detection limits of nitrate obtained with TDAN + DOS and TDAN + DBP, are 10–6 mol/dm3 and 10–9 mol/dm3, respectively. As a result, the developed sensors based on TDAN + DOS and TDAN + DBP matrices demonstrate satisfactory quantified amounts in determination of nitrate in water where the measured values were less than 0.57 × 10–7 mol/dm3 and 0.73 × 10–10 mol/dm3, respectively.     

Elasticity of the B2 phase and the effect of the B1–B2 phase transition on the elasticity of MgO

A study of the high-pressure anisotropy of MgO was conducted using first-principles calculations based on density functional theory within the generalized gradient approximations. The pressure dependence of the elastic stiffness coefficients and the anisotropy parameters, in both B1 and B2 phases, shows that for high-hydrostatic compression the easiest deformation is the shear along (100) plane and the the material's response to deformation and to shearing strains is quite the same. According to the calculations of the velocities of propagation of elastic waves, we deduced that MgO develop an elastic anisotropy, especially, in the B1 phase. We present the B2 phase elastic properties which are not already studied under high pressure.     

Hydrodynamic Effects in Soft‐matter Self‐assembly: The Case of J‐Aggregates of Amphiphilic Porphyrins

Chiral J‐aggregates of achiral amphiphilic porphyrins (4‐sulfonatophenyl and aryl meso‐substituted porphyrins) show several effects under the hydrodynamic forces of common stirring. These effects can be classified as pure mechanic (e. g. elasticity, plasticity and breaking of the self‐assembly non‐covalent bonding) and chemically selective as detected in the formation/growth of the nanoparticles. Diastereoselective, enantioselective and, depending on the sign of chiral shear forces, even enantiospecific selections have been described. Some types of these effects have been reported in other type of J‐aggregates. Reversible and irreversible structural effects have been studied by atomic force imaging. The determination of the optical polarization properties (linear and circular) of their solutions is best done using Mueller matrix polarimetry methods.     

Flow-based integer linear programs to solve the weekly log-truck scheduling problem

Annals of Operations Research - In this paper we present the solution to a weekly log-truck scheduling problem (LTSP) integrating the routing and scheduling of trucks where all goods are...     

Clique inference process for solving Max-CSP

Few works on problems CSP, Max-CSP and weighted CSP was carried out in the field of Combinatorial Optimization, whereas this field contains many algorithmic tools which can be used for the resolution of these problems.In this paper, we introduce the binary clique concept: clique which expresses incompatibilities between values of two CSP variables. We propose a linear formulation for any binary clique and we present several ways to exploit it in order to compute lower bounds or to solve Max-CSP. We also show that the binary clique concept can be exploited in the weighted CSP framework.The obtained theoretical and experimental results are very interesting and they open new prospects to exploit the Combinatorial Optimization algorithmic tools for the resolution of CSP, Max-CSP and weighted CSP.