On the identification of symmetry‐forbidden spin subspaces for configurations employing nonorthogonal orbitals

The implications of orbital symmetry for a configuration's spin function are considered from the fairly general viewpoint required for multiconfiguration wave functions employing nonorthogonal orbitals. A general procedure is derived for the imposition of the spin constraints that may be necessary to ensure a given configuration, or a set of configurations as a whole, exhibit required symmetry properties, thus preventing symmetry contamination of the overall electronic wave function. © 2000 John Wiley & Sons, Inc. Int J Quant Chem 78: 24–31, 2000     

Phonon spectra and unit cell analysis of 2-cyanothiophene

Vibrational spectra of 2-cyanothiophene in the solid state reveal that the crystals are ordered below the freezing point and have an orthorhombic C_2v unit cell. Intermolecular forces between the two molecules occupying the Bravais unit are not strong enough to promote the separation of all the Davidov doublets of the phonon states.     

Environmental Fate of Organic Sunscreens during Water Disinfection Processes: The Formation of Degradation By-Products and Their Toxicological Profiles

The development of any commercial product should also be aimed at reducing the risk associated with it, according to the safe-by-design concept; that is, risk assessment should always be at the center of the design, and the impact on human and environmental health should be assessed and eliminated during the product development phase and not afterwards. Unfortunately, even today, most operators in any production sector implement the philosophy of “risk management” or rather of managing the problem when it occurs, using spot interventions instead of changing the approach. This argument is also valid in the production of solar filters, which have reached a satisfactory degree of efficiency in the face of a substantial underestimation of the risks associated with their possible environmental fate. In fact, solar filters have been found in bathing waters and their environmental fate may depend on various factors such as the pH of the water, the presence of organic material, metal ions and light, and, above all, the chemical agents used in the disinfection of the water itself. Thus, during disinfection processes, the generation of dozens of products with a lower molecular weight and generally of an aromatic nature has been tested, where some of them did not receive an exact structural definition and a precise evaluation of their precise toxicological profile. Therefore, it is interesting to draw a complete picture of organic sunscreens and of the byproducts obtained under different conditions and their related ecotoxicological profile.     

Optically Transparent Gold Nanoparticles for DSSC Counter-Electrode: An Electrochemical Characterization

A gold nanoparticles transparent electrode was realized by chemical reduction. This work aims to compare the transparent gold nanoparticles electrode with a more commonly utilized gold-film-coated electrode in order to investigate its potential use as counter-electrode (CE) in dye-sensitized solar cells (DSSCs). A series of DSSC devices, utilizing I⁻/I³⁻ and Co(III)/(II) polypyridine redox mediators [Co(dtb)3]³⁺/²⁺; dtb = 4,4′ditert-butyl-2,2′-bipyridine)], were evaluated. The investigation focused firstly on the structural characterization of the deposited gold layers and then on the electrochemical study. The novelty of the work is the realization of a gold nanoparticles CE that reached 80% of average visible transmittance. We finally examined the performance of the transparent gold nanoparticles CE in DSSC devices. A maximum power conversion efficiency (PCE) of 4.56% was obtained with a commercial I⁻/I³⁻-based electrolyte, while a maximum 3.1% of PCE was obtained with the homemade Co-based electrolyte.     

Fluid interface detection technique based on neighborhood particles centroid deviation (NPCD) for particle methods

Particle‐based CFD methods are powerful approaches to investigate free surface, multiphase flows, and fluid structure interaction problems because of their ability of tracking moving fluid interface even with huge deformations or fragmentation and merging. However, many fluid interface particle detection techniques are simple to implement but with low accuracy or provide relatively good detection results at complicated implementation cost or higher computational time. In case of incompressible flow simulation methods solving the Poisson equation of pressure, such as the moving particle semi‐implicit method, boundary particles detection techniques' accuracy affects precision and stability of pressure computation and interaction between fluid phases. In the present work, a new fluid interface particle detection technique is proposed to improve the accuracy of the boundary particles detection and keep the implementation easy. Denominated as the neighborhood particles centroid deviation technique, it is a two‐criteria technique based on the particle number density and the neighborhood particles weighted geometric center deviation. Compared with other techniques, the proposed neighborhood particles centroid deviation technique shows the best results by eliminating false interface particles inside the fluid domain and keeping the interface particles layer thin and regular. As a result, relatively stable pressure time histories and more consistent pressure and velocity fields are achieved. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.     

Affine Kähler hypersurfaces satisfying certain conditions on the curvature tensor

The notion of affine Kähler immersions has been recently introduced by Nomizu-Pinkall-Podestà ([N-Pi-Po]). This work is aimed at giving some results towards the classification of non degenerate affine Kähler hypersurfaces with symmetric and parallel Ricci tensor; this problem generalizes the classical results due to Nomizu-Smyth ([N-S]) in the theory of Kählerian hypersurfaces. In a second section we deal with the case of “semisymmetric” affine Kähler immersions, when the curvature tensor R satisfies R · R = 0 and the Ricci tensor is symmetric, providing a complete classification; for affine Kähler curves we prove that the conditions above are actually equivalent to saying that the immersion is isometric for a suitable Kähler metric in C².