Search results for "IR measurement"
showing 5 items of 5 documents
Postharvest quality and sensory attributes of ‘pesca di bivona’ peaches (Prunus persica L.) during storage
2017
“Pesca di Bivona” ‘Murtiddara’, ‘Bianca’, ‘Agostina’, and ‘Settembrina’ are non-melting white flesh peach landraces characterized by a persistent aroma and excellent flavour highly appreciated by Italian consumers. The aim of this work was to assess the persistence of their quality and sensory profiles after storage at 0 °C for 28 days, using destructive and non-destructive analyses. The IAD index, measured either at harvest or at fruit removal from cold storage, was correlated to TSS, TA and firmness of all the landraces. ‘Settembrina’ and ‘Agostina’ harvested at the right ripening time (50.5 ± 4.3 N) and stored at 0 °C during 4 weeks kept harvest quality in terms of sensorial attributes, …
Thermally Induced Structural Modification of Silica Nanoparticles Investigated by Raman and Infrared Absorption Spectroscopies
2010
We report an experimental investigation by Raman and infrared (IR) absorption spectroscopies on the structural modifications induced by isochronal thermal treatments on amorphous SiO2 nanoparticles (fumed silica). In particular, three different commercial types of this material, characterized by particle mean diameters of 7, 14, and 40 nm, were subjected to thermal treatments from 100 up to 1000 °C. We found that some properties of fumed silica, such as the SiOSi mean bond angle, ring size distribution, and surface adsorbed water content, are drastically different from those of common bulk silica materials and intimately related to the particles' dimension. The SiOSi mean bond angle, probed…
Temperature effects on the IR absorption bands of hydroxyl and deuteroxyl groups in silica glass
2009
Abstract In this report we will show the changes of the band shape of the hydroxyl group (SiOH) infrared (IR) absorption band (∼3670 cm −1 ) in silica glass induced by lowering temperature in the range from 290 to 20 K. This band is considered as the overlap of several spectral components associated to the vibrational activity of hydroxyl groups in different bond configurations. By a suitable analysis of the experimental band profile in terms of different sub-bands, we studied the thermal evolution of each component and we reconsidered their assignations. For comparison we examined the SiOD absorption band (∼2710 cm −1 ) as a function of temperature as well. Our data can be interpreted as a…
Irradiation effects on the absorption edge of silica glass
2007
Abstract Vacuum ultraviolet absorption experiments were carried out on a variety of specimens of amorphous silica β-irradiated at different doses from ∼103 to 5 × 106 kGy. Changes in the width of the absorption (Urbach) edge were investigated. These changes strongly depend on the kind of silica considered: in particular the Urbach energy of silica of industrial manufacture increases in the irradiated samples, whereas in sol–gel silica it is poorly influenced by the irradiation. The fictive temperature of the different materials before and after irradiation was also monitored. The changes of the Urbach energy and of the fictive temperature are tentatively discussed considering the disorder d…
The Influence of Fruit Ripening Stage at Harvest and Storage Temperature on ‘Bianca di Bivona’ White Flesh Peaches
2015
‘Bianca di Bivona’ is a white-flesh peach cultivar, which ripens during the last week of July and the first of August. Its fruit are known because of their distinct flavor and aroma, which make them highly accepted, particularly in the local markets. However, nothing is known about their postharvest physiology and storage conditions. In order to investigate the effect of: (a) fruit ripening stage at harvest and, (b) storage temperatures, ‘Bianca di Bivona’ peaches were picked at mature-green, (60.0±1.3 N), and ripe stage (30.7 ± 2.1 N) determined by flesh firmness, and then stored at 0°C and 5°C (90% RH). Flesh firmness, total soluble solids, titratable acidity, weight loss and DA index, me…