In Situ Synchrotron Study of B19 Phase Formation in an Intermetallic γ‐TiAl Alloy

A multitude of phases exists in the binary Ti–Al phase diagram and even greater numbers are formed in structural TiAl alloys, which contain additional alloying elements to improve their properties. In the current study, a Ti–45 Al–3 Mo–0.1 B (in at%) alloy was investigated with respect to the phases occurring in chemical non‐equilibrium. In situ high‐energy X‐ray diffraction experiments enabled to identify a transient phase to be of the B19 type and to determine its temperatures of formation and dissolution.     

Observation of kinks and antikinks in colloidal monolayers driven across ordered surfaces

Friction between solids is responsible for many phenomena such as earthquakes, wear or crack propagation. Unlike macroscopic objects, which only touch locally owing to their surface roughness, spatially extended contacts form between atomically flat surfaces. They are described by the Frenkel-Kontorova model, which considers a monolayer of interacting particles on a periodic substrate potential. In addition to the well-known stick-slip motion, such models also predict the formation of kinks and antikinks, which greatly reduce the friction between the monolayer and the substrate. Here, we report the direct observation of kinks and antikinks in a two-dimensional colloidal crystal that is driven across different types of ordered substrate. We show that the frictional properties only depend on the number and density of such excitations, which propagate through the monolayer along the direction of the applied force. In addition, we also observe kinks on quasicrystalline surfaces, which demonstrates that they are not limited to periodic substrates but occur under more general conditions.     

Effect of Fluorine on the Phase Separation of Na2O-SiO2 Glasses

Immiscibility temperature of 13 mol% Na₂O-87 mol% SiO₂ glass was found to increase with F addition. Electron micrographs indicated that the microstructure size did not change appreciably with F addition.     

EFFECTS OF BODY COMPOSITION AND FIRING TREATMENT ON SALT GLAZES1

Five synthetic bodies were made up in which the silica, alumina, ferric oxide, and alkalis were varied. Salts were added to these bodies in various amounts; the bodies were dried and fired under carefully controlled conditions and salt glazed under oxidizing conditions at cones 2, 5, and 7 and under reducing conditions at cone 5. The effects of body composition and glazing temperature on the appearance of the bodies are giveu. Reducing conditions during glazing increased the glaze thickness. The maturity of the glaze is more important than the thickness. Devitrification of the glazes is more important than the presence of impurities. Crystals of hematite, acmite, nephelite, and carnegieite were found in the glazes. Firing treatment has a greater influence on glaze character than chemical composition.     

Galactorrhea-amenorrhea syndromes: etiology and treatment

Clinical and renal morphologic studies are reported in a 3 1/2 month old infant with congenital syphilis and nephrotic syndrome. Renal lesions were consistent with membranous proliferative glomerulonephritis, and the presence of glomerular deposits of IgM, C3, and of less intensity of IgE and fibrin, were demonstrated by means of immunofluorescence. These findings identify the renal lesion as an immune glomerulopathy. A therapeutic course of penicillin resulted in resolution of clinical manifestations without any evidence of persistent renal damage.     

Wood shrinkage: influence of anatomy, cell wall architecture, chemical composition and cambial age

The influence of microfibril angle (MfA), density and chemical cell wall composition on shrinkage varied between the longitudinal and tangential directions as well as between wood types, namely compression wood (CW), mature wood (MW) and juvenile wood (JW). At the same MfA, CW exhibited a lower tangential shrinkage than JW, indicating the influence of the chemical composition on wood shrinkage. The chemical composition measured via FTIR micro-spectroscopy has been shown in conjunction with density to be an alternative to MfA data for shrinkage predictions. This was particularly true for wood of young cambial age for which the MfA did not correlate to shrinkage. The results indicate a possibility to reduce distortion of sawn timber by segregation using infrared (IR) and X-ray in-line measurements.