Stability to oxidation of virgin olive oils as related to olive conditions: Study of polar compounds by chemometric methods

Polar compounds of virgin olive oils were analyzed. They influence oil flavor and aroma and improve the shelf-life of the oil. The orthodiphenolic fraction is particularly significant for oil stability because of its antioxidative activity. A relationship between the composition of the whole fraction of polar compounds and the state of health of the olives was established. For this purpose, oil samples were obtained from olives that had reached different degrees of ripeness and that had been affected by Dacus oleae infestation differently. The polar compounds were then analyzed by high-performance liquid chromatography. The data set was studied by means of chemometric methods. Partial least squares regression was used to obtain models that show a significant correlation between composition of the oil’s polar compounds and conditions of the olives sampled. In particular, compounds with antioxidative activity were directly linked with the state of health of the olives. The models obtained allow tracing of the state of health of the olives sampled through analysis of the polar fraction of virgin olive oil with a high degree of accuracy, and thus prediction of the oil’s expected shelf life.     

Effect of inter-layer strain interaction on the optical properties of Ge/Si（001） island multi-layers

In this paper we present a study on the influence of the number and the thickness of silicon spacer layer on the optical properties of single-and multi-layers of self assembled Ge/Si(001) islands performed by means of cathodoluminescence spectroscopy,high resolution X-ray diffraction and transmission electron microscopy. In single-layer sample,we do not evidence dependence of the island no-phonon emission peak position on the silicon cap-layer thickness. In multi-layer samples having a thin(33 nm) silicon spacer layer the no-phonon emission energy value progressively blue-shifts for an increasing number of island layers. This is interpreted as an enhanced intermixing driven by the strain interaction existing between island layers. On the contrary,island emission energy position is independent on the number of layers in the sample series having a thicker spacer layer(60 nm) . These findings are consistent with the X-ray diffraction observation that islands belonging to different layers have the same composition. As a consequence we can conclude that multilayers with 60-nm spaced islands layer are more homogeneous and ordered.     

Measurement of mechanical loads in large wind turbines: Problems on calibration of strain gage bridges and analysis of uncertainty

The paper discusses the complexity of calibration of strain gage full bridges applied to measure mechanical loads in large wind turbines, when direct application of calibration loads is not feasible. In particular, at first, it presents a generalized static‐dynamic mechanical model which allows to calibrate the strain gage full bridges using its own unbalanced masses to generate known reference inputs. Then, the paper discusses the uncertainty associated to such a calibration, according to the ISO/IEC Guide 98‐3:2008 “Guide to the Expression of Uncertainty in Measurement”. The uncertainty of the reference input and the following calibration is discussed, which is often larger than the target set by the standard IEC‐61400‐13 used for wind turbine type certification. The paper comments on the attainable range of calibration which is rather limited with respect to expected load range in operation. Even if calibration should take place in isothermal effects, this is not always the case in real world practice. Therefore, the thermal effects on strain gage bridges are also discussed, putting into evidence its influence on calibration uncertainty both for full bridges in T configuration and in parallel configuration.     

Deterioration of protein fraction by Maillard reaction in dietetic milks.

The development of the Maillard reaction in pasteurized, UHT and in-bottle sterilized dietetic milks was studied. In these products damage caused by heat treatments could increase as a result either of the addition of various ingredients or of manufacturing processes that alter their content of reducing carbohydrates. Protein damage was evaluated by measuring furosine by reversed-phase ion-paired HPLC. The levels of furosine detected made it possible to assess the amounts of biologically unavailable lysine. In all milks analysed blocked lysine values were < 340-350 mg/g total lysine, the level at which lysine becomes the limiting amino acid in milk. Pasteurized dietetic milks had levels of blocked lysine similar to that in ordinary pasteurized cows' milk. In some UHT and in-bottle sterilized dietetic milks their different composition resulted in an increase in the blocked lysine content. In some in-bottle sterilized milks, protein damage greatly reduces the beneficial effects of milk as a dietary supplement. Lactose-free milks, which are more susceptible to protein deterioration because of their higher content of reducing carbohydrates, were also analysed after storage at 20 degrees C and at < or = 4 degrees C. At the end of their recommended storage times, they contained limited amounts of blocked lysine only if they had been stored at < or = 4 degrees C.     

Carbon-Supported Au Nanoparticles: Catalytic Activity Ruled Out by Carbon Support

The catalytic oxidation of glycerol produces high added value chemical products. Gold-based catalysts showed activity and selectivity depending on particle size and specific preparation method. Moreover, the support plays a fundamental role in modulating the stability of the catalytic system. However, the literature is still lacking of a precise disclosure of these important relationships. Herein, we synthesized two series of gold catalysts on different carbon supports (Vulcan-XC72R, X40S and Norit GSX), the first synthesized by solvated metal atom deposition (SMAD) and the second by Sol Immobilization technique (SOL). First of all, the specific physico-chemical properties of the supports and the synthesis procedure influenced the dispersion and the size of Au NPs making a direct comparison among the different carbon difficult. In particular, on Vulcan-XC72R, AuNPs showed narrow size and good dispersion, whereas on Norit GSX and X40S-Camel a notably wider size distribution has been revealed. XPS analyses showed Au exposure changed accordingly to the presence of oxygen species, lower O content corresponding to lower Au exposure. Unexpectedly however this does not correspond to a lower activity, being the lowest Au/C (%at), the Vulcan ones, the most active catalysts. Comparing SOL and SMAD prepared samples on the same carbon, the SOL ones always result more active.     

Mt. Cimone Observatory: baseline station for the measurement of gaseous substances and radioactive tracers in the atmosphere

An extensive research program to record atmospheric physicochemical parameters and to track climatological trends was established at a remote Alpine station at Mt. Cimone Observatory in Italy. The main features of the study are outlined briefly and the results thus far collected, including surface ozone, carbon dioxide, stratospheric NO2 and O3, and airborne radioactivity are provided.     

System partitioning and its measure

Program modules and data structures are interconnected by calls and references in software systems. Partitioning these entities into clusters reduces complexity. For very large systems manual clustering is impractical. A method to perform automatic clustering is described and a metric to quantify the complexity of the resulting partition is developed.