Cracks in glass under triaxial conditions

This experimental work documents the mechanical evolution of synthetic glass (SON68) under compressive triaxial stresses (hydrostatic and deviatoric conditions). The experimental setup enabled to monitor and vary independently confining pressure (range: [0, 50] MPa) and axial stress (up to 680 MPa) at room temperature. An optimized set of sensors allowed us to perform measurements during the experiments of: (i) axial and radial deformation, (ii) P- and S-elastic wave velocities, and (iii) acoustic emissions. In addition, in some samples, initial crack densities up to a value of 0.24 were introduced by thermal cracking. We compare the original synthetic glass data set to results obtained in the same experimental conditions on thermally cracked glass and on a basaltic rock with similar petrophysical properties (porosity, chemistry).Stress-strain data depict original linear elastic glass properties even up to an axial stress of 680 MPa (under 15 MPa confining pressure). A strong strength decrease (370 MPa at 15 MPa confining pressure) is observed for thermally cracked samples. Elastic wave velocity data highlight that cracks are mostly closed at a confining pressure of ∼30 MPa. The basaltic rock seems to correspond to an intermediate state between an original and a thermally treated glass. In all samples, damage was accompanied by dynamic crack propagation, producing large magnitude acoustic emissions. Thanks to a continuous recorder, we could locate a number of acoustic emissions in order to image the microcracking pattern evolution prior to failure.     

Shock-Vortex Interactions at High Mach Numbers

We perform a computational study of the interaction of a planar shock wave with a cylindrical vortex. We use a particularly robust High Resolution Shock Capturing scheme, Marquina's scheme, to obtain high quality, high resolution numerical simulations of the interaction. In the case of a very-strong shock/vortex encounter, we observe a severe reorganization of the flow field in the downstream region, which seems to be due mainly to the strength of the shock. The numerical data is analyzed to study the driving mechanisms for the production of vorticity in the interaction.     

When syndromal similarity obscures functional dissimilarity: Distinctive evoked environments of externalizing and mixed syndrome boys.

This research examined how syndromal approaches to assessment can obscure differences between children in the quality of their social interactions. Mixed boys (high for externalizing and internalizing problems) showed heterogeneity in the responses they evoked from others: For one subgroup, aggression and withdrawal evoked aversive responses from others, and even prosocial behavior evoked hostile peer responses; for the other, aggression and withdrawal evoked positive peer responses. Externalizing boys also showed heterogeneity in the patterning of their evoked responses. Within-group heterogeneity was not explained by boys' syndrome scores but was linked to their reactions to specific antecedent events. The results illustrate how a contextualized analysis of behavior can reveal distinctive social interactional patterns that underlie similar overall rates of problem behaviors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

New fat products: Glyceride esters of adipic acid

Summary Six new glyceride esters of adipic acid were prepared, and their properties were determined. By the Presented at the 49th Annual Meeting of the American Oil Chemists' Society, Memphis, Tenn., April 21–23, 1958. One of the laboratories of the Southern Utilization Research and Development Division, Agricultural Research Service, U. S. Department of Agriculture.     

The role of cognitive development in children's explanations and preferences for skin color.

One Black and 1 White female examiner assessed 72 White 2.5–10.5 yr old children to investigate children's understanding of the origins of race and explore the developmental concomitants of skin color preferences. Ss' understanding of the origins of race followed a developmental hierarchy and correlated significantly with performance on previously researched measures of physical conservation, physical causality, and social identity. Both physical conservation and physical causality appeared to be developmental prerequisites to understanding the origins of race. Significant Race?×?Cognitive Developmental Level interactions indicated that pro-White bias was significantly lower for higher levels of cognitive development when the examiner was Black. The possibility that skin color preference is influenced by social desirability is discussed. (30 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Third International Congress for Stereology

This article gives a survey of the actual experience with the relatively new technique of photo-emission electron microscopy. After describing the principal technique and the features of a modern high resolution instrument, the questions of image generation, contrast formation and resolution are considered. In particular the influence of the depth of information on resolution for flat polished sections is studied and some comparisons with the scanning electron microscope (SEM) are made.* The different fields of application of the photo-EEM are shown by examples.     

Hydrolysis of glycosidically bound flavour compounds from oak wood by Oenococcus oeni

Malolactic fermentation (MLF), which is conducted by lactic acid bacteria (LAB), has a significant influence on the stability and organoleptic quality of wine. Recent studies have shown that when MLF is carried out in oak wood barrels, LAB were also able to interact with wood and increase volatile compound contents such as vanillin during MLF. The release of these compounds indicates that LAB may convert vanillin precursors present in oak wood. In this work, the effect of commercial glycosidases on the released vanillin was firstly studied. This aldehyde is present in wood extracts in monoglycosidic forms where the major glycones are arabinose and xylose. Other aglycons released during MLF in barrels, syringaldehyde and whisky-lactones, can be considered as other sources of aroma. Secondly, strains selected with high activities toward glycoside substrates could hydrolyse vanillin glycoside precursors from oak wood with the same efficiency as commercial enzymes.     

Microstructural,mechanical and tribological properties of suspension plasma sprayed YSZ/h-BN composite coating

Brittleness, relative high friction coefficient and wear rate limit the applications of ceramic coatings as wear-resistant layers. However, because embedding additives with ceramic matrix has demonstrated to be an effective way to improve coating performances, different contents and size of h-BN were added into an YSZ suspension. Afterwards, the YSZ/h-BN composite coatings were manufactured by suspension plasma spray and their tribological analysis indicated that: i) the reduction of the friction coefficient and wear rate can be achieved by incorporating h-BN into YSZ coating. ii) finer h-BN particle is more helpful to enhance the tribological properties of the coating. iii) the optimum content is dependent on h-BN particle sizes. iv) when the contents and the size of the h-BN inclusion increase, the probability distribution of the micro-hardness can become bi-modal. Three worn surface conditions were summarized and their wear mechanisms were discussed as well.