Protection of lithium metal surfaces using chlorosilanes

In this paper, we present a new approach for protecting metallic lithium surfaces based on a reaction between the thin native layer of lithium hydroxide present on the surface and various chlorosilane derivatives. The chemical composition of the resulting layer and the chemistry involved in layer formation were analyzed by polarization modulated infrared reflection absorption spectroscopy (PM-IRRAS), X-ray photoelectron spectroscopy (XPS), and energy dispersive X-ray analysis (EDX). Spectroscopy shows the disappearance of surface hydroxide groups and the appearance of silicon and chloride on the lithium surface. Differential scanning calorimetry (DSC) and electrochemical impedance spectroscopy (EIS) show that this surface treatment protects the lithium from certain gas-phase reactions and is ionically conductive.     

Distribution of n-alkanes, polynuclear aromatic hydrocarbons and nitrated polynuclear aromatic hydrocarbons between the fine and coarse fractions of inhalable atmospheric particulates.

The distribution ratios of n-alkanes, polynuclear aromatic hydrocarbons (PAHs) and nitrated PAH components between fine and coarse fractions of soot has been investigated in downtown Rome through three field campaigns carried out at different times of the year. The preferential accumulation of almost all species investigated onto fine particles has been observed in all field experiments performed. Moreover, nitrated PAHs had varied distributions, according to the origin of their occurrence in the atmosphere; in fact, congeners of photochemical origin accumulated more in fine particles than those released by primary sources.     

A Polymer-Supported Phosphazine as a Stable and Practical Reagent in the Three-Component Synthesis of Substituted (Cyclopentadienyl)tricarbonylrhenium Complexes

A very stable heterogenized difunctional cyclopentadienyl-ring precursor , storable under ambient conditions, readily participates in the simultaneous formation of a η⁵ bond with a [fac-Re(CO)₃]⁺ species and a σ bond with heteroatom (halides, carboxylates) or carbon nucleophiles (boronic acids) to produce halo-, acyloxy-, or carbon-substituted cyclopentadienyl–Re(CO)₃ complexes in a one-pot reaction in yields of between 41 and 71 % [Eq. (1)]. No catalyst is required and unprotected (usually) sensitive functional groups are well tolerated.     

Tomographic Study of Internal Erosion of Particle Flows in Porous Media

In particle-laden flows through porous media, porosity and permeability are significantly affected by the deposition and erosion of particles. Experiments show that the permeability evolution of a porous medium with respect to a particle suspension is not smooth, but rather exhibits significant jumps followed by longer periods of continuous permeability decrease. Their origin seems to be related to internal flow path reorganization by avalanches of deposited material due to erosion inside the porous medium. We apply neutron tomography to resolve the spatiotemporal evolution of the pore space during clogging and unclogging to prove the hypothesis of flow path reorganization behind the permeability jumps. This mechanistic understanding of clogging phenomena is relevant for a number of applications from oil production to filters or suffosion as the mechanisms behind sinkhole formation.     

Interplay of stereoelectronic and enviromental effects in tuning the structural and magnetic properties of a prototypical spin probe: further insights from a first principle dynamical approach

The nitrogen isotropic hyperfine coupling constant (hcc) and the g tensor of a prototypical spin probe (di-tert-butyl nitroxide, DTBN) in aqueous solution have been investigated by means of an integrated computational approach including Car-Parrinello molecular dynamics and quantum mechanical calculations involving a discrete-continuum embedding. The quantitative agreement between computed and experimental parameters fully validates our integrated approach. Decoupling of the structural, dynamical, and environmental contributions acting onto the spectral observables allows an unbiased judgment of the role played by different effects in determining the overall experimental observables and highlights the importance of finite-temperature vibrational averaging. Together with their intrinsic interest, our results pave the route toward more reliable interpretations of EPR parameters of complex systems of biological and technological relevance.     

Interaction of sodium ions with cationic surfactant interfaces

The thermodynamically stable microemulsion and lamellar phases in the didodecyldimethylammonium bromide/water/n-decane ternary system were explored in the presence of NaBr to gain information on sodium ion-interface interactions. Experimental results, obtained by different NMR techniques, strongly suggest accumulation of sodium ions at the cationic interface. This apparently counterintuitive result is explained by invoking the dispersion potential experienced by the ions near the interface. A mechanism is proposed that can account for the dramatic shrinkage of the microemulsion phase region when an electrolyte is added.     

Synthesis of 1,3-dihydrobenzo[c]furans from ortho-lithiated aryloxiranes

A general method for the synthesis of hydroxyalkyl 1,3-dihydrobenzo[c]furans from ortho-lithiated aryloxiranes and carbonyl compounds is described.     

On damage detection by continuous dynamic monitoring in wind-excited suspension bridges

The paper discusses the application of dynamic methods for damage detection in the main cables of suspension bridges, using data continuously recorded under wind excitation through permanent monitoring systems and automated operational modal analysis. A continuum model for predicting the vertical aeroelastic response of wind-excited damaged suspension bridges is formulated and presented at first. The model shows that, for a real sample bridge, typical variations of mean wind speed produce variations of natural frequencies, due to aeroelastic effects, that are more significant than those produced by a small damage. A possible solution to this issue, proposed in the paper, consists of removing the dependence on the excitation source by calculating frequency shifts considering frequencies, in reference and damaged states, associated to approximately the same mean wind speed. This task and the necessary estimation of frequency shifts through a statistical analysis of identified natural frequencies outline the need for a continuous dynamic monitoring. The analytical model is finally employed for generating dynamic wind response data that are successively processed by means of an advanced automated modal identification tool. Although based on the simplifications inherently contained in the analytical model, the results show that frequency shifts caused by a relatively small damage can be accurately estimated from response data recorded under wind excitation with a reasonable number of data sets.