The growth of crystalline vapor deposited carbon-60 thin films

Thin films (25-2500 Å) of C₆₀ molecules have been deposited on both (001) NaCl and mica substrates at varying temperatures by resistive evaporation. Both electron diffraction and high resolution microscopy have been used to assess the degree of crystallinity, the orientational ordering and the nature of the defects present in these face-centered-cubic films. For NaCl, optimum conditions yielded polycrystalline films with a tendency towards a 110 orientation, while for mica, extended single crystal films have been fabricated which exhibit a 111 direction normal to the film surface.     

A class of piecewise interpolating functions based on barycentric coordinates

Piecewise interpolation methods, as spline or Hermite cubic interpolation methods, define the interpolant function by means of polynomial pieces and ensure that some regularity conditions are guaranteed at the break-points. In this work, we propose a novel class of piecewise interpolating functions whose expression depends on the barycentric coordinates and a suitable weight function. The underlying idea is to specialize to the 1D settings some aspects of techniques widely used in multi-dimensional interpolation, namely Shepard’s, barycentric and triangle-based blending methods. We show the properties of convergence for the interpolating functions and discuss how, in some cases, the properties of regularity that characterize the weight function are reflected on the interpolant function. Numerical experiments, applied to some case studies and real scenarios, show the benefit of our method compared to other interpolant models.     

Thermodynamic characteristics of a biological organism: Information value of a gene and of a protein as a measure of the efficiency and as an index of selective pressure

Summary For the treatment of the information exchanged by the biological system and the external world, the concept of information amount is not sufficient because of their remoteness from equilibrium states. Further explanations are, in fact, necessary about the effects of the reception of the message,i.e. its information value that is then necessary to define for each case. We have, therefore, defined the information value of a gene and of a protein and analysed a sample of about hundred genes looking for some significative regularity in the frequency of usage of codons and amino acids allowing us to individualize the salient characteristics of a translated sequence of codons. We have found that the most used amino acids have, on the average, a low information value and, for each amino acid type, the most used codons have a lower information value. Moreover, we can say that the composition in amino acids or in codons of a sequence useful for the biological systems is such that more frequent mutations cause the smaller variation in the phenotype. All that shows that our definitions well describe the system of transmission and reception of the information value in a biological organism and that they can be considered as an index of its efficiency,i.e. of its ability to minimize the effects of the mutation of the genotype on the phenotype. To speed up publication, the authors of this paper have agreed to not receive the proofs for correction.     

Determination of sixteen polycyclic aromatic hydrocarbons in aqueous and solid samples from an Italian wastewater treatment plant

A robust procedure for the determination of 16 US EPA PAHs in both aqueous (e.g. wastewaters, industrial discharges, treated effluents) and solid samples (e.g. suspended solids and sludge) from a wastewater treatment plant (WWTP) is presented. Recovery experiments using different percentages of organic modifier, sorbents and eluting solvent mixtures were carried out in Milli-Q water (1000 mL) spiked with a mixture of the PAH analytes (100 ng/L of each analyte). The solid phase extraction (SPE) procedures applied to spiked waste water samples (1000 mL; 100 ng/L spiking level) permitted simultaneous recovery of all the 16PAHs with yields >70% (6-13% RSD). SPE clean up procedures applied to sewage and stabilized sludge extracts, showed percent recoveries in the range 73-92% (7-13% RSD) and 71-89% (7-12% RSD), respectively. The methods were used for the determination of PAHs in aqueous and solid samples from the WWTP of Fusina (Venice, Italy). Mean concentrations, as the sum of the 16PAHs in aqueous and suspended solid samples, were found to be approx. in the 1.12-4.62 microg/L range. Sewage and stabilized sludge samples contained mean PAH concentrations, as sum of 16 compounds, in the concentration range of 1.44-1.26 mg/kg, respectively. Extraction and clean up procedures for sludge samples were validated using EPA certified reference material IRM-104 (CRM No. 912). Instrumental analyses were performed by coupling HPLC with UV-diode array detection (UV-DAD) and fluorescence detection (FLD).     

Homo‐ and Copolymerization of Butadiene Catalyzed by an Bis(imino)pyridyl Vanadium Complex

Summary: The bis(imino)pyridyl vanadium(III ) complex [VCl₃{2,6‐bis[(2,6‐iPr₂C₆H₃)NC(Me)]₂(C₅H₃N)}] activated with different aluminium cocatalysts (AlEt₂Cl, Al₂Et₃Cl₃, MAO) promotes chemoselective 1,4‐polymerization of butadiene with activity values higher than classical vanadium‐chloride‐based catalysts. The polymer structure depends on the nature of the cocatalyst employed. The MAO‐activated complex was also found to be active in ethylene‐butadiene copolymerization, producing copolymers with up to 45 mol‐% of trans‐1,4‐butadiene. Crystalline polyethylene and trans‐1,4‐poly(butadiene) segments were detected in these copolymers by DSC and ¹³C NMR spectroscopy.

     

Stochastic modelling of solar-radiation data

Summary Daily global solar-radiation sequences are studied for Italy. We show that the experimental data can be described as a first-order autoregressive stochastic process independent of locality or season: the only climatic information needed is the monthly average of the clearness index. We also show that the clearness index sequences can be transformed in sequences with normal distribution but with the same autocorrelation properties; it is then easy to construct synthetic sequences of radiation data with the same statistical properties as the real data, useful for performance prediction of solar systems.

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Riassunto Si analizzano le serie temporali dei valori giornalieriK _T (rapporto tra la radiazione solare globale su superficie orizzontale e la radiazione extra-atmosferica) per il territorio italiano. Si dimostra che i dati possono essere descritti con processi stocastici autoregressivi del primo ordine indipendentemente dalla località o stagione: la sola informazione necessaria è il valore medio mensile dei rapportiK _T . Si dimostra inoltre che le successioni dei valoriK _T possono essere trasformate in successioni con funzione di distribuzione normale e con le stesse caratteristiche statistiche di autocorrelazione dei dati originari; in tal modo è poi possibile costruire successioni di dati di radiazione, di lunghezza pari al numero di giorni in un mese e con le stesse proprietà statistiche dei dati sperimentali, utili per il calcolo delle prestazioni di sistemi solari.

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