Thermal behavior and evolution of the mineral phases of Brazilian red mud

This article studied the thermal behavior and the evolution of the crystalline phases with temperature of the red mud (bauxite tailing) from an aluminum industry at Maranhão, North-Northwestern Brazil. The experiments were carried out by Field Emission Scanning Electron Microscopy (FE-SEM), Simultaneous Thermal Analysis (TG–DSC), Optical Dilatometry up to 1623 K, and X-ray diffraction (XRD) of previously heated samples between 523 and 1523 K. The crystalline phases and the amorphous contents were quantified on raw and heated samples (at 1523 K) according to the Rietveld Quantitative Analysis (RQA) method. The data obtained showed that the raw red mud is composed by a mixture of seven different phases (hematite, goethite, sodalite, anatase, gibbsite, calcite, and amorphous). Finally in the interval of 1023–1523 K the following crystalline phases: hematite, nepheline, sodalite, anatase, perovskite, and pseudobrookite have been observed.     

Analyzing sub-100-μm samples with transmission terahertz time domain spectroscopy

The authors propose a method for the extraction of material parameter and thickness information from sub-100-μm thin samples using non-differential transmission terahertz time domain spectroscopy. The approach relies on an additional Fourier transform of the frequency dependent material parameters to a quasi space regime. In this quasi space, periodic Fabry-Perot oscillations from the frequency domain, which originate from multiple reflections inside the sample, correspond to discrete peaks. By iterative minimization of these peaks, the highly precise thickness information along with the refractive index and absorption coefficient of the sample can be determined. Experimental verification of the approach is also provided.     

Paramagnetische Resonanz an Einkristallen einiger Selten-Erd-Oxide

The paramagnetic resonance of Nd³⁺ in Y₂O₃ has been measured at 4.2°K and 9.25 kMe/s. The values of theg-tensors are: ions onC _3i -sites:g _∥=2.434±0.007;g _⊥=0.702±0.005; ions onC ₂-sites:g _x =4.395±0.012;g _y =0.433±0.009;g _z =1.648±0.006. Further measurements have been performed on La₂O₃ crystals doped with Ce³⁺, Dy³⁺, and Er³⁺; the results are (C _3v -sites only): .      

Consistent density deconvolution under partially known error distribution

We estimate the distribution of a real-valued random variable from contaminated observations. The additive error is supposed to be normally distributed, but with an unknown variance. The distribution is identifiable from the observations if we restrict the class of considered distributions by a simple condition in the time domain. A minimum distance estimator is shown to be consistent imposing only a slightly stronger assumption than the identification condition.     

Micro-fabricated metal nozzle plates used for water-in-oil and oil-in-water emulsification

In this paper the fabrication and use of micro-structured metal nozzle plates as emulsification devices is investigated and discussed. These structured metal nozzle plates were fabricated via two distinct routes. Laser ablation, performed with a femtosecond laser, was used to drill micrometer-sized holes into stainless steel and aluminum foils. Also a conventional steel mesh with an average pore size of 2.4 μm fabricated by weaving and roll compaction of micrometer-sized steel wires was investigated. The perforated metal nozzle plates were used for oil-in-water and after hydrophobization with alkylchlorosilanes for water-in-oil emulsification as well. In both cases, two types of drop formation processes were observed. The first one is the shear-induced drop formation well known for cross-flow membrane emulsification. The second is the spontaneous drop formation known from microchannel emulsification.