Mechanical Properties of Melt-Grown Alumina–Yttrium Aluminum Garnet Eutectics up to 1900 K

Alumina/yttrium aluminum garnet (YAG) eutectic rods of 1 mm in diameter were grown by the laser-heated floating zone method at different rates to obtain microstructures with the same morphology but of very different domain size. The mechanical properties of the rods (hardness, toughness, strength) were measured at ambient temperature in the longitudinal and transverse directions and, in addition, the longitudinal flexure strength was determined up to 1900 K. The fracture resistance and the hardness of the eutectics at ambient temperature were isotropic and independent of the domain size. On the contrary, the longitudinal strength was significantly higher than the transverse one and increased linearly with the growth rate, reaching almost 2 GPa in the rods grown at 750 mm/h, which presented a submicrometer homogeneous microstructure. The critical defect size was equivalent to that of Al₂O₃ and YAG domains in the microstructure, and the strength was proportional to the inverse of the square root of the domain size. In addition, the strength retention of the eutectics was remarkable, and the rods with the finest microstructure withstood 1.53 GPa at 1900 K. The moderate reduction in strength at very high temperature was induced by the homogeneous coarsening of the microstructure.     

Studies of the quality of cakes made with wheat-lentil composite flours

Legume flours, due to their amino acid balance and their demonstrated nutritional benefits, are ideal ingredients to improve the nutritional characteristics of bakery products. We have studied the inclusion of lentil flour on layer and sponge cakes, and its effect on the characteristics of the batter and of the final product. The addition of lentil flours reduced the density of layer-cake batter but increased the density of sponge-cake batter. This effect was greater with the smaller flour-particle size. Adding lentil flour to the formula reduced layer-cake volume, symmetry index, cohesiveness and springiness and increased hardness. In sponge cakes, no clear tendencies were observed in volume or symmetry index, but the total substitution of wheat flour by lentil flour gave rise to harder and less cohesive cakes. The use of lentil flour with a fine particle size increased cake volume but reduced hardness, particularly in sponge cakes.     

Adequacy of different wheat cultivars for low-hydration bread making

BACKGROUND: There is considerable interest in recovering landraces as genetic resources and as raw materials in ecological production. Low-hydration bread, whose dough is submitted to a sheeting roll process, is commonly prepared in Spain and other countries. The aim of this study was to assess the adequacy of some landraces, compared with commercial cultivars and flours, for making this type of bread. Eight Spanish landraces, four wheat cultivars developed during the green revolution and three commercial flours were chosen, their alveographic and kneading behaviours were analysed and the characteristics of the resulting breads were determined. RESULTS: The best correlations were obtained in breads with improver. Flours with extreme alveographic behaviour differed markedly from the rest. When these flours were excluded from the analysis, the parameters best correlated with bread quality (when using improver) were strength, tenacity and development time. A significant correlation between flour colour, a genetic factor, and crumb colour was found. This correlation was higher in breads without improver. CONCLUSION When flours with extreme characteristics were removed, the protein quality characteristics of flours defined the quality characteristics of low-hydration breads.     

Effect of Extruded Wheat Germ on Dough Rheology and Bread Quality

Wheat germ, a by-product of the milling industry, has interesting nutritional properties. However, it has limited use due to a high risk of rancidity, which could be reduced by using certain thermal treatments such as extrusion. The aim of this study was to investigate how wheat germ extrusion affects the changes induced by its addition to bread dough. For this purpose, different quantities of extruded or raw wheat germ (2.5, 5, 7.5, 10, and 20?g/100?g flour) were added to bread dough. Rheological characteristics of the dough and final quality characteristics of the bread were analysed from both the physical and the sensory points of view. Wheat germ addition increased water absorption and development time but decreased stability after over-kneading, dough tenacity, extensibility, and dough alveographic strength. The addition of extruded wheat dough improved stability and decreased extensibility and strength. Bread made from dough with added wheat germ presented decreased volume, cohesiveness, and elasticity and increased firmness. However, extrusion increased the volume of breads with added wheat germ and improver and decreased firmness. All breads obtained positive acceptability scores in sensory analysis, although wheat germ addition (10?g/100?g flour) slightly decreased texture, appearance, and overall acceptability scores of breads. Germ extrusion therefore improves dough rheology and bread quality and constitutes a suitable treatment to stabilise wheat germ in bread dough.     

Nutritional characteristics of veal from weaned and unweaned calves: Discriminatory ability of the fat profile

The chemical and nutritional composition of the Longissimus thoracis muscle from 58 'Rubia Gallega' breed animals was measured to differentiate veal of weaned from unweaned calves. Fat, protein, ash, and moisture contents of muscle were determined by near infrared reflectance spectroscopy (NIRS) and the fatty acid (FA) profiles were determined by gas chromatography. Calves suckled their mothers at pasture followed by an indoor period. The weaned group was finished on concentrates indoors, whereas the unweaned group was continued suckling with a complementary concentrate diet, also indoors. The unweaned group had higher total FA (p<0.001), monounsaturated (MUFA) (p<0.05) and polyunsaturated (PUFA) (p<0.05) FA contents, lower saturated FA (SFA) (p<0.01) concentration, and a higher PUFA:SFA ratio (p<0.05) than the weaned group. A multivariate step discriminant procedure selected nine variables out of 38 tested from the FA profile. The SFA fraction lower than C11 followed by the margaric FA and the n-6:n-3 PUFA ratio were the most discriminating variables for separating the weaning classes, regardless of the gender. Calibration and cross-validation misclassification errors were 0% and 1.67%, respectively. A more powerful discriminant function was estimated for males only, where the SFA fraction lower than C11 followed by tricosanoic, and margaric FA were the most discriminant, with zero misclassification errors.     

Short communication: Intra- and inter-individual milk microbiota variability in healthy and infected water buffalo udder quarters

The concept that ruminant mammary gland quarters are anatomically and physiologically unrelated has been recently challenged by immunological evidence. How this interdependence reflects on individual quarter milk microbiota is unknown. The aim of the present study was to cover this gap by investigating the interdependence of quarters among the same mammary gland at the milk microbiota level using next-generation sequencing of the V4–16S rRNA gene. A total of 52 samples were included in this study and classified as healthy or affected by subclinical mastitis. Extraction of DNA, amplification of the V4–16S rRNA gene, and sequencing using Ion Torrent Personal Genome Machine (Thermo Fisher Scientific, Waltham, MA) were carried out. We found that the intra-individual variability was lower than the inter-individual one. The present findings further support at milk microbiota level the hypothesis of the interdependence of quarters, as previously demonstrated following immunological studies, suggesting that individual factors (e.g., immunity, genetics) may have a role in modulating milk microbiota.     

Applying SVMs and weight-based factor analysis to unsupervised adaptation for speaker verification

This paper presents an extended study on the implementation of support vector machine (SVM) based speaker verification in systems that employ continuous progressive model adaptation using the weight-based factor analysis model. The weight-based factor analysis model compensates for session variations in unsupervised scenarios by incorporating trial confidence measures in the general statistics used in the inter-session variability modelling process. Employing weight-based factor analysis in Gaussian mixture models (GMMs) was recently found to provide significant performance gains to unsupervised classification. Further improvements in performance were found through the integration of SVM-based classification in the system by means of GMM supervectors.This study focuses particularly on the way in which a client is represented in the SVM kernel space using single and multiple target supervectors. Experimental results indicate that training client SVMs using a single target supervector maximises performance while exhibiting a certain robustness to the inclusion of impostor training data in the model. Furthermore, the inclusion of low-scoring target trials in the adaptation process is investigated where they were found to significantly aid performance.     

Study of the electrochemical oxidation and reduction of C.I. Reactive Orange 4 in sodium sulphate alkaline solutions

Synthetic solutions of hydrolysed C.I. Reactive Orange 4, a monoazo textile dye commercially named Procion Orange MX-2R (PMX2R) and colour index number C.I. 18260, was exposed to electrochemical treatment under galvanostatic conditions and Na₂SO₄ as electrolyte. The influence of the electrochemical process as well as the applied current density was evaluated. Ti/SnO₂–Sb–Pt and stainless steel electrodes were used as anode and cathode, respectively, and the intermediates generated on the cathode during electrochemical reduction were investigated. Aliquots of the solutions treated were analysed by UV–visible and FTIR-ATR spectroscopy confirming the presence of aromatic structures in solution when an electro-reduction was carried out. Electro-oxidation degraded both the azo group and aromatic structures. HPLC measures revealed that all processes followed pseudo-first order kinetics and decolourisation rates showed a considerable dependency on the applied current density. CV experiments and XPS analyses were carried out to study the behaviour of both PMX2R and intermediates and to analyse the state of the cathode after the electrochemical reduction, respectively. It was observed the presence of a main intermediate in solution after an electrochemical reduction whose chemical structure is similar to 2-amino-1,5-naphthalenedisulphonic acid. Moreover, the analysis of the cathode surface after electrochemical reduction reveals the presence of a coating layer with organic nature.