PM-10 and heavy metals in particulate matter of the province of Lecce (Apulia, Southern Italy)

This paper shows the results of a preliminary study of air monitoring in the province of Lecce (Apulia, Southern Italy). In particular, the attention has been focused on the determination of the PM-10 level and of the concentration of nine metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb, V and Zn) present on the filters which were collected in two towns (Lecce and Campi Salentina) from 2002 until 2003. The metals have been chosen on the basis of their toxicity and of their possible use as chemical tracers. The results have proved that PM-10 values and metals concentrations did not show substantial difference between the two towns and that PM-10 level and lead concentration are below the limit established by Italian law in force. The experiments have demonstrated a high correlation between iron and manganese in both sampling sites; this could be attributed to pollution of metallurgical origin. Multivariate statistical analysis, carried out by HCA and PCA methods, has been used in order to differentiate samples in relation to sampling sites, sampling period and meteorological conditions.     

Minimax strategy for optimal simple inspection plan design

Mathematical Methods of Operations Research - After providing minimax strategy in simple and composite hypothesis testing for optimal simple inspection plan design, this paper examines...     

Relativistic korringa-kohn-rostoker CPA theory: Extension tol=3 scattering channel

Summary We have extended the well-known relativistic KKR-CPA theory up tol≤3 angular momentum, in order to make this framework suitable to deal with rare-earth alloys. However, such an extension has also relevance in judging the convergence of the KKR-CPA calculations even for those atomic species with empty valencef-states. To do that we worked out the transformation from the usual real spherical harmonics to the cubic double-point group representatin. We have tested the present theory and corresponding codes by computing the electronic structure of Cu_0.75−Au_0.25 and by comparing our results with earlierl≤2 R-KKR-CPA calculations. In order to reduce the large amount of computing time required, we have also used a new technique for the Brillouin zone integration. Work sponsored also by CRRN/SM.     

“Normal” and “cine” substitution in the thioalkoxy-dehalogenation of halogenobenzofuranzans—II: Sensibility of each pathway to the change of alkanethiolate ion

Thioalkoxy-dehalogenation of 4-halogenobenzofurazans affording “normal” and “cine” substitution products has been more extensively investigated. Evidence for a partial intervention of AEa-type mechanism in NS product formation is now available. The competition of this pathway increases with the bulkiness of thiolate ion. Kinetic data for different thiolates are reported indicating a sensitivity to steric effects not only in the “normal” substitution but also in the “cine” substitution pathway.     

Robustness of raw quantum tomography

We scrutinize the effects of non-ideal data acquisition on the tomograms of quantum states. The presence of a weight function, schematizing the effects of a finite window or equivalently noise, only affects the state reconstruction procedure by a normalization constant. The results are extended to a discrete mesh and show that quantum tomography is robust under incomplete and approximate knowledge of tomograms.     

Auf einige neue Luftpumpenkonstruktionen

Ohne Zusammenfassung     

Nanoemulsions for the Determination of the Antioxidant Capacity of Oils by an Electrochemical Method

The paper describes a rapid and simple method for the evaluation of the antioxidant capacity in oil in water nanoemulsion. This procedure does not require extensive sample treatment and, most important, does not use any organic solvent for dissolution of the fatty matrix. The nanoemulsions were directly injected in a flow injection (FI) system with an electrochemical detector equipped with a glassy carbon working electrode operating amperometrically at a potential of +0.8 V (vs. Ag/AgCl). Results obtained were compared with those obtained by the Oxygen Radical Absorbance Capacity (ORAC) assay.     

Influence of compatibilizer degradation on formation and properties of PA6/organoclay nanocomposites

Nanocomposites based on polyamide 6 (PA6) and commercial layered silicates have been prepared by both in situ polymerization and melt compounding. The main aim of the present work has been centred on compatibilizer degradation, caused by the preparation conditions, in terms of nanocomposite end features. Two montmorillonite (MMT)-type, organically-modified clays (OMLS), namely Cloisite 30B^® and Nanofil 784^®, and a sodium MMT (Cloisite Na^®) have been studied. Thermal properties of the layered silicates have been evaluated by TGA, IR, WAXD and pyrolysis-gas-mass. In order to better assess the influence of high temperature processes on clay modifications, a thermal treatment which mimics the conditions used during the in situ polymerization (4 h at 250 °C) has been applied on layered silicates. The above treatment, besides the elimination of absorbed water from all the clays, turned out to prove noteworthy differences in compatibilizer modification for the two organoclays. Indeed, in the case of Closite 30B^® only a removal of organic molecules outside the silicate galleries and a likely reorganization of those present inside the galleries have been detected, while a relevant chemical modification of Nanofil 784^® compatibilizer has been conversely found.As far as nanocomposite characteristics are concerned, the latter have been found to depend on both the preparation method and clay type. In the case of in situ polymerization, also thermally-treated layered silicates, coded (T), have been used, in order to put more clearly in evidence the role of compatibilizer decomposition on nanocomposite formation and properties. Indeed, nanocomposite samples containing Closite 30B^®(T) have been found to be completely exfoliated, while the same thermal treatment seems to make worse the properties of those based on Nanofil 784^®(T). Furthermore, with respect to nanocomposites based on pristine clays, samples containing thermally-treated silicates turned out to be different in terms of both molecular mass and crystal structure of the polymer matrix. Namely, PA6 γ-form seems to be promoted for all nanocomposites prepared in such a way, probably because of water removal at high temperature, which makes -OH groups of the layered silicate more free to interact with polyamide chains, thus causing a restriction of their mobility.     

Finite-volume modelling of system with compressible flow propelled and actuated body motion

A finite-volume model for the gas flow in a compressible flow driven system with two moving components is developed and applied. In this system, high pressure and temperature compressible flow propels one body along a main flow channel. When this body passes an opening in the main flow channel, some of the high pressure gas bleeds off, entering a secondary, telescoping, flow channel that empties into a plenum. The bleed-off flow causes the pressure in the plenum to increase, actuating the motion of a secondary (actuated) body that forms a bounding surface of the plenum, causing the plenum to expand and the secondary channel to lengthen.     

Dynamical origin of the quantum Zeno effect

The quantum Zeno effect is often studied and understood in term of nonunitary evolutions, involving projections à la von Neumann (measurements). We propose a dynamical explanation of this effect, which involves only unitary operators. The limit of infinitely frequent measurements is critically discussed: it is unphysical, yet interesting and peculiar.