Search results for " UV"

Complexation of phosphine ligands with peracetylated β-cyclodextrin in supercritical carbon dioxide: Effect of temperature and cosolvent on the equil…

2009

Abstract The interaction between peracetylated-β-cyclodextrin and tert-butyl and adamantyl functionalized triphenylphosphine derivatives was studied in supercritical carbon dioxide (scCO 2 ) based solvent media by UV–vis spectroscopy. The equilibrium constant for a 1:1 complexation reaction was obtained from titration spectra both in pure carbon dioxide and in the presence of methanol as a cosolvent in the temperature range 308–323 K to estimate the internal energy and entropy of the inclusion equilibrium. The values of the equilibrium constants were found significantly smaller than those obtained in aqueous solution with analogous phosphines and substantially independent of the nature of t…

Equilibria involved in the diorganotin(IV) and triorganotin(IV) phosphomycin interaction in aqueous solution

2007

Four new diorganotin(IV), (R = Me, Bu), and triorganotin(IV), (R = Me, Ph), derivatives of the phosphomycin disodium salt antibiotic[(1R,2S)-1,2-epoxypropylphosphonate]Na2 have been synthesized and their solid state configuration studied by X-ray crystallography, FT-IR, Mossbauer, UV–Vis spectroscopies. The X-ray diffraction investigation, performed on the bis[trimethyltin(IV)]- phosphomycin, showed that the coordination geometry at all the Sn atoms is trigonal bipyramidal. The structure of the complex forms an unusual polymeric zig-zag planar network. The FT-IR and the 119Sn Mo¨ssbauer studies supported the formation of trigonal bipyramidal (Tbp) molecular structures, both in the diorganot…

A new equipment to measure the combined effect of humidity, temperature, mechanical stress and UV exposure on the creep behaviour of polymers

2008

To be able to study and predict the physical properties of a polymeric material under different environmental conditions is very important. Moisture, UV irradiation, thermal and mechanical stresses can dramatically change the characteristics of the material and hinder some specific applications. In this work, a new equipment able to perform creep tests under different environmental conditions (temperature, humidity, stress) is presented. Some preliminary results are also presented using a sample of polyamide 6. As this polymer is sensitive to all these variables, it is appropriate to verify the effectiveness of the new instrument.

Evoluzione dei composti fenolici durante la maturazione di uve Nero d’Avola, Merlot e Cabernet Sauvignon nella Sicilia occidentale

2012

Simulation Study of a Space-Based detector for UHECR observation.

2005

The next generation of experiments devoted to the study of the cosmic rays spectrum above 10(20) eV will be most likely done by means of space based detectors. In order to detect the fluorescence and Cerenkov signal generated by an EAS in atmosphere, severe requirements on the photon collection efficiency and on the triggering capability need to be met. In this paper we report about of preliminary studies of the triggering efficiency of a space based detector as a function of the main detector parameters. All results are obtained by means of a detailed simulation of the shower development, atmospheric response, detector geometry and electronics and trigger behavior in realistic conditions b…

Desarrollo de métodos analíticos para la determinación de filtros UV: de los productos cosméticos al cuerpo humano y al medio ambiente

2015

La presente Tesis Doctoral forma parte del Proyecto de Investigación CTQ 2009-12709 titulado “Desarrollo de métodos analíticos para la detección y cuantificación de trazas: de los productos cosméticos al cuerpo humano”. Todos los estudios realizados están relacionados con un grupo de ingredientes cosméticos denominados “filtros UV”, de gran interés desde el punto de vista de la salud por el importante papel que ejercen en la protección de los usuarios frente a la radiación solar. Se han desarrollado diversos métodos analíticos para la determinación de filtros UV con el fin de que puedan servir para contribuir a la realización de tres tipos de estudios que abarcan la cadena producto cosmétic…

Così la pratica dell'inerbimento migliora la qualità del vino

2008

Effect of environmental stress on sea urchin embryos and larvae: from developmental to molecular biology analyses

2010

Desarrollo de nuevas estrategias de microextracción. Aplicación a la determinación de filtros UV en muestras de agua de interés medioambiental

2016

Las técnicas de microextracción aportan numerosas ventajas a la etapa de preparación de la muestra. Algunas de estas técnicas están actualmente bien establecidas y se han implementado en numerosos laboratorios analíticos, aunque también se han descrito algunas limitaciones. En la presente Tesis Doctoral se ha contribuido al desarrollo y validación de nuevas estrategias analíticas basadas en técnicas de microextracción, y se han aportado algunas mejoras a las ya existentes, obteniéndose buenas características como rapidez, bajo coste, simplicidad y respeto hacia el medio ambiente y el operador (“Química Verde”). Para evaluar la aplicabilidad de estas nuevas estrategias, se han aplicado a la …

The flavour components of mirabelle plums. Examination of the aroma constituents of fresh fruits: Variation of headspace composition induced by deep-…

1986

The flavour components of mirabelle plums. Examination of the aroma constituents of fresh fruits: Variation of headspace composition induced by deep-freezing and thawing