Performance of a Nozzle to Control Bath Level Oscillations and Turbulence of the Metal-Flux Interface in Slab Molds

The characterization of the turbulent flow of liquid steel in a slab mold using a commercial nozzle was carried out through physical experiments and mathematical models. Six ultrasonic sensors were located at each side of the nozzle to obtain real-time plotting of the bath levels during the experimental time. An ultrasonic transducer located in the mold, 20 mm below the meniscus, determines the velocities and the turbulent variables along with the distance from the narrow face to the position of the nozzle’s outer wall. These data, together with the mathematical simulations, demonstrated a high correlation of bath level oscillations and the time-dependent behavior of the discharging jets. The flow inside the mold shows low-frequency non-symmetric patterns without a severe turbulent in the meniscus. The source of this instability is the partial opening of the slide valve gate used to control the mass flow of liquid.

Influence of Impurities on the Front Velocity of Sputter Deposited Al/CuO Thermite Multilayers

CuO and Al thin films were successively deposited using direct current (reactive) magnetron sputter deposition. A multilayer of five bilayers was deposited on glass, which can be ignited by heating a Ti resistive thin film. The velocity of the reaction front which propagates along the multilayer was optically determined using a high-speed camera. During the deposition of the aluminum layers, air was intentionally leaked into the vacuum chamber to introduce impurities in the film. Depositions at different impurity/metal flux ratios were performed. The front velocity reaches a value of approximately 20 m/s at low flux ratios but drops to approximately 7 m/s at flux ratios between 0.6 and 1. The drop is rather abrupt as the front velocity stays constant above flux ratios larger than 1. This behavior is explained based on the hindrance of the oxygen transport from the oxidizer (CuO) to the fuel (Al).

Metal Flux from Dissolution of Iron Oxide Grain Coatings in Sandstones

Iron oxide grain coatings in red sandstones contain trace metals that are released upon dissolution of the coatings. Analyses by ICP-MS following acid leaching of the grain coatings show that the dissolved metals can constitute an ore-forming fluid, as hypothesized in models for sandstone-hosted ore deposits. Median compositions of 37 samples, mostly of Triassic to Devonian age, from across Britain and Ireland are 6.3 ppm copper, 2.4 ppm cobalt, 10.1 ppm vanadium, and 0.3 ppm uranium. These contents at the basin scale are adequate to form the observed range of ore deposits in red beds. The migration of hydrocarbons or brines can cause the dissolution of grain coatings and contributes to controlling the distribution of ore deposits. Future measurements should test red beds derived from uplifted, mineralized plate margins, in which sandstones may be preloaded with ore metals.

The structure of Ce2Al3Ge4 refined for the first time from single-crystal X-ray diffraction data

Single crystals of dicerium trialuminium tetragermanide, Ce2Al3Ge4, have been synthesized from a high-temperature reaction using an eutectic mixture of Al and Ge as a metal flux. Through single-crystal X-ray diffraction it was established that Ce2Al3Ge4 crystallizes in the centrosymmetric space group Cmce (No. 64) with the Ba2Cd3Bi4 structure type (Pearson code oC36). Five atoms compose the asymmetric unit, i.e. one Ce, two Al, and two Ge atoms, all in special positions with Wyckoff symbols 8f (Ce), 4a and 8e (Al), and 8e and 8f (Ge). The structure can be described as a three-dimensional network of Al and Ge atoms, with Ce atoms occupying the cavities of the framework.