DISPERSION POLYMERIZATION OF STYRENE STARTING FROM MICROEMULSIONS

The domains of homogeneity for the systems containing styrene - alcohol (methanol, isopropanol, t-butanol) - water are investigated. These ones represent the reaction medium of dispersion polymerization The domains of homogeneity increase with increasing the hydrocarbon chain of the cosurfactant and in the presence of surfactants. Conductometric and refractometric studies have established that the homogeneous systems obtained in the presence of monomaleate of nonylphenol ethoxylated with 25 moles ethylene oxide, in a concentration of 10% based on the above-mentioned mixture, are microemulsions with oil-in-water (o/ w) bicontinuous or water-in-oil (w/ o) structure. In the presence of 10% bismethacrylate of PEG 1500 or 5% bismethacrylate of PEG 1500 and 5% acrylic acid, based on styrene, the domains of homogeneity are smaller, but the character of microemulsion is preserved. The latexes prepared by polymerizing styrene dispersed in microemulsions display larger particle diameter in case of isopropanol, owing to partial swelling.     

Doped (Nd,Ba)FeO3 oxides as potential electrodes for symmetrically designed protonic ceramic electrochemical cells

Journal of Solid State Electrochemistry - The design of new electrode materials with high redox stability has great potential for the fabrication of solid oxide fuel and electrolysis cells having a...     

Relationship between tribology and optics in thin films of mechanically oriented nanocrystals

Many crystalline dyes, when rubbed unidirectionally with cotton on glass slides, can be organized as thin films of highly aligned nanocrystals. Commonly, the linear birefringence and linear dichroism of these films resemble the optical properties of single crystals, indicating precisely oriented particles. Of 186 colored compounds, 122 showed sharp extinction and 50 were distinctly linearly dichroic. Of the latter 50 compounds, 88% were more optically dense when linearly polarized light was aligned with the rubbing axis. The mechanical properties of crystals that underlie the nonstatistical correlation between tribological processes and the direction of electron oscillations in absorption bands are discussed. The features that give rise to the orientation of dye crystallites naturally extend to colorless molecular crystals.     

Poincaré series of modules over compressed Gorenstein local rings

Given two positive integers e and s we consider Gorenstein Artinian local rings R   whose maximal ideal m$\mathfrak{m}$ satisfies m^s≠0=m^s+1${\mathfrak{m}}^s\ne 0={\mathfrak{m}}^{s+1}$ and _rankR/m(m/m²)=e${\mathrm{rank}}_{R/\mathfrak{m}}(\mathfrak{m}/{\mathfrak{m}}^2)=e$. We say that R is a compressed Gorenstein local ring   when it has maximal length among such rings. It is known that generic Gorenstein Artinian algebras are compressed. If s≠3$s\ne 3$, we prove that the Poincaré series of all finitely generated modules over a compressed Gorenstein local ring are rational, sharing a common denominator. A formula for the denominator is given. When s is even this formula depends only on the integers e and s  . Note that for s=3$s=3$ examples of compressed Gorenstein local rings with transcendental Poincaré series exist, due to Bøgvad.     

Linear π‐Acceptor‐Templated Dynamic Clipping to Macrobicycles and [2]Rotaxanes

Cage me! A linear dumbbell‐shaped bipyridinium molecule can template cage formation around itself through sixfold imine bond formation to give an interlocked [2]rotaxane as the single product (see picture). This highly efficient [2+3] clipping occurs despite the symmetry mismatch between the template and the formed macrobicycle.

     

Multilayered nanofibers from stacks of single-molecular thick nanosheets of hexakis(alkoxy)triphenylenes

Symmetrically substituted hexakis(alkoxy)triphenylene (HAT) derivatives were assembled into single molecular thick 2D nanosheets, which stacked further to give multilayered nanofibers through a convenient solution process. Detailed information on molecular arrangement was unraveled by various imaging techniques and diffraction studies.     

A prolongation of the conformal-Killing operator on quaternionic-K?hler manifolds

A 2-form on a quaternionic-K?hler manifold (M, g) of dimension 4n ≥ 8 is called compatible (with the quaternionic structure) if it is a section of the direct sum bundle ${S^{2}H \oplus S^{2}E}$ . We construct a prolongation ${\mathcal D}$ of the conformal-Killing operator acting on compatible 2-forms. We show that ${\mathcal D}$ is flat if and only if the quaternionic-Weyl tensor of (M, g) vanishes. Consequences of this result are developed. We construct a skew-symmetric multiplication on the space of conformal-Killing 2-forms on (M, g), and we study its properties in connection with the subspace of compatible conformal-Killing 2-forms.     

Cash management cost reduction using data mining to forecast cash demand and LP to optimize resources

This paper presents a two step model aimed at reducing cash management costs in a bank’s branch. First, data mining was used to forecast daily cash demand, comparing an ARMA-ARCH model with a neural network. Secondly, using the prior result, a linear programming model was solved. The optimal allocation of resources, i.e., cash collections and supplies was estimated showing that the model can be a helpful tool to support the determination of collections and supplies at the bank branch.