Defect structure of metal oxides at high temperatures

High temperature oxidation of some metals contained in special alloys has been studied. Defect models for pure an doped CoO and pure NiO were developed and fitted to electrical conductivity data. The models involve different kinds of theoretically possible complex defects with different numbers of vacancies and interstitials forming a cluster. Equilibrium constants for defects formation have been estimated using an algorithm based on the constrained variation method that allows fitting of data to implicit models involving errors in all the measured variables. Results indicate the presence of a significant concentration of complex defects in CoO at high temperatures, while confirming the rather small concentration of these defects in NiO.     

Catalytic wet oxidation of phenol over lanthanum strontium manganite

The catalytic performances of lanthanum strontium manganite (La_0.8Sr_0.2)Mn_0.98O₃, in catalytic wet oxidation (CWO) of a phenol solution under milder conditions of temperature (398–498 K) and pressure (P_o2=4 bar), in a batch reactor, have been investigated. Aim of this study is the evaluation of the effect of temperature, catalyst loading, phenol concentration and stirrer speed on phenol conversion. Experimental data obtained from the different test conditions are best-fitted to evaluate the effective reaction order and apparent activation energy.     

Structural and rheological properties of medium-chain triacylglyceride oleogels

This research studied the effect of gelator molecules on structural properties of oleogels containing medium-chain triacylglycerides (MCTs). To this aim, a large selection of gelators (rapeseed wax RAW, rice wax RW, sunflower wax SW, beeswax BW, monoglycerides MG, and γ-oryzanol and β-sitosterol mixture γ+β) at increasing concentrations (5–15% w/w) was considered. Results showed that RAW was not able to structure MCT at any concentration. However, addition of 5% (w/w) of MG, SW and BW resulted to a self-standing gel. Regarding γ+β and RW, gel structures were generated at 10% (w/w). By increasing the concentration, a reinforcement of the network strength was highlighted by the progressive increase of the rheological parameters. The strongest oleogel obtained by γ+β at 10% (w/w) and further BW and RW at 15% (w/w) concentration. These findings could provide interesting information in the choice of the best performing MCT structuring agent for intended food applications.     

A study on multimedia documents behavior: a notion of equivalence

In this paper we address the problem of comparing multimedia documents, which can be described according to different reference models. If we consider pre- sentations as collections of media items and constraints among them, expressed ac- cording to their reference model, they must be translated to a common formalism in order to compare their temporal behavior and detect if they have a common component (i.e., intersection), if one of them is included in another one (i.e., inclusion), or if they have the same temporal evolution along time (i.e., equivalence). In this paper, we propose the use of automata, to describe the temporal evolution of a document, and the SMIL language as a case study, since this standard allows to describe the same behavior with different sets of tags. In case of behaviorally equivalent SMIL documents, we propose an algorithm to extract the canonical form that represents this behavior.

Determination of Cu(II) in Beer by Derivative Potentiometric Stripping Analysis

Derivative Potentiometric‐Stripping Analysis (dPSA) is described as an inexpensive and rapid method for the determination of Cu(II) in beer. Beer samples were analysed directly after degassing and addition of the analytical reagents (hydrochloric acid, mercury(II) chloride, and potassium metabisulfite). It was not necessary to digest the sample. During dPSA the metal ions are deposited on a glassy carbon‐working electrode and then stripped by a suitable oxidant. Quantitative analysis was carried out by the method of standard additions. The recovery of the method was tested by adding 50 μg L^?1, 75 μg L^?1 and 100 μg L^?1 of Cu(II) (as Cu(II) chloride solution) to the beer. The mean recoveries of Cu(II) ranged from 95 ± 5% to 98 ± 2%. The reproducibility was evaluated by three repetitive analyses for each sample and the standard deviation ranged from 0.6 μg L^?1 to 5.5 μg L^?1. The detection limit was 0.8 μg L^?1. The Cu(II) concentration determined in seven beer samples ranged from 28 μg L^?1 to 48 μg L^?1 and the results obtained were not significantly different from those obtained by atomic absorption spectrophotometry (AAS).     

Influence of barley variety, timing of nitrogen fertilisation and sunn pest infestation on malting and brewing

BACKGROUND: This paper presents a multivariate approach to investigate the influence of barley variety, timing of nitrogen fertilisation and sunn pest infestation on malting and brewing. Four spring and two winter barley varieties were grown in one location in southern Europe. Moreover, one of the spring varieties was infested with sunn pest, in order to study the effects of this pest on malting quality, and subjected to different nitrogen fertilisation timing regimes. The samples were micromalted, mashed, brewed and analysed. RESULTS: The data showed that even though the two winter barleys seemed to be the best regarding their physical appearance (sieving fraction I + II > 82%), this superiority was not confirmed in the malt samples, which showed low values of Hartong extract (27.1%) and high values of pH (6.07–6.11) and β‐glucan content (12.5–13.2 g kg^?1), resulting in low‐quality beers. The barley sample subjected to postponed fertilisation had a total nitrogen content (19.5 g kg^?1 dry matter) exceeding the specification for malting barley and gave a beer with a low content of free amino nitrogen (47 mg L^?1) and high values of viscosity (1.99 cP) and β‐glucan content (533 mg L^?1). The beer obtained from the barley sample subjected to pest attack had good quality parameters. CONCLUSION: All spring barleys gave well‐modified malts and consequently beers of higher quality than the winter barleys. Moreover, postponed fertilisation was negatively related to the quality of the final beer, and sunn pest infestation did not induce important economic losses in the beer production chain. Copyright © 2010 Society of Chemical Industry