Electroless etching of Si with (IO3)- and related species

ABSTRACT: We have previously derived seven requirements for the formulation of effective stain etchants and have demonstrated that Fe3+, Ce4+ and (VO2)+ + HF solutions are highly effective at producing nanocrystalline porous silicon. Here we show that Cl2, Br2, I2, ClO3-, BrO3-, (IO3)-, I- and (I3)- induce etching of silicon when added to HF. However, using the strict definition that a pore is deeper than it is wide, we observe little evidence for porous layers of significant thickness but facile formation of pits. Iodate solutions are extremely reactive and by the combined effects of (IO3)-, (I3)- , I2 and I-, these etchants roughen and restructure the substrate to form a variety of structures including (circular, rectangular or triangular) pits, pyramids or combinations of pits and pyramids without leaving a porous silicon layer of significant thickness.     

Trends in der Kontrolle von Aufbereitungsprozessen

The past decade has seen some interesting developments in the fields of regulatory and advanced process control for mineral processing plants, in terms of: (i) the suite control techniques now commonly used; (ii) the introduction of new advanced sensing technologies; and, (iii) peripheral developments in near real-time applications. In process control, the use of artificial intelligence techniques, phenomenological models and model predictive control provide the process engineer with a powerful suite of tools to develop/maintain complex and effective control strategies. In sensing, machine vision applications for flotation froths, balling drums, and the particle size measurement for haul trucks, feeders, conveyors etc. have enabled improved control performance. Finally, in the near real-time area, data mining, dynamic simulation, and abnormal condition management have opened up new applications for process control. This paper provides an overview of the trends based on industrial examples drawn from Metso’s more than two decades of experiences in process control projects for the global mining community.     

The influence of exopolysaccharide-producing lactic acid bacteria on reconstructed ham

The influence of in-situ-formed exopolysaccharides (EPS) by lactic acid bacteria (LAB; Lactobacillus sakeiTMW 1.411 and Lactobacillus plantarumTMW 1.1478) on the yield and texture of reconstructed ham was investigated. No differences in yield (P > 0.05) were observed but weight loss during storage was significantly higher (P < 0.05) for hams produced with L. sakei 1.411. Furthermore, the produced EPS decreased the hardness (P < 0.05; 50.22 N for control compared to 44.81 N) but did not influence the cohesiveness (P > 0.05) of hams. Products with L. plantarum 1.1478 showed no significant differences in comparison to the control. This could be attributed to the lower amount of EPS formed during ripening. L. sakei 1.411 produced 194.49 ± 5.34 mg kg⁻¹ EPS, whereas L. plantarum 1.1478 formed 60.26 ± 2.96 mg kg⁻¹ EPS. Thus, the use of the examined LAB is not recommended in reconstructed ham, since they have no or even a negative influence on the product quality.     

Investigation of the effect of light on the electrical parameters of Si/TiO2 heterojunctions produced by anodic oxidation on p-type Si wafer

Journal of Materials Science: Materials in Electronics - Fabrication of heterojunctions of Si combined with TiO2 oxide-based semiconductors is an alternative method to produce cost effective...     

Biocompatible polymers as a tool for the synthesis of silver nanoparticles: size tuning and in vitro cytotoxicity studies

Silver nanoparticles have attracted great attention in the biomedical research field, especially in cancer theranostics. In this study, we developed a synthesis method for silver nanoparticles in the solid state using high‐speed vibration milling, in which biocompatible polymers such as poly(vinylpyrrolidone), poly(ethylene glycol) and chitosan were used for the reduction of the silver salt. The synthesis of the size‐tunable silver nanoparticles was performed at room temperature and no surfactants to direct the anisotropic growth of the nanoparticles were required. The formation of the nanoparticles was studied using UV‐visible and Fourier transform infrared spectroscopy as well as transmission electron microscopy. The synthesized nanoparticles showed an average diameter ranging from 3.1 ± 1.4 to 22.8 ± 5.8 nm. In addition, the anticancer activity of these silver nanoparticles was assessed using cytotoxicity studies with human breast adenocarcinoma (MCF‐7), human lung adenocarcinoma (NCI‐H358) and mouse embryonic fibroblast (NIH‐3T3) cell lines. Accordingly, an effective suppression of the proliferation of cell growth was found. © 2016 Society of Chemical Industry     

Modellprädiktive Regelung für das Bandeinfädeln in der Warmwalzstraße

In this contribution we introduce a new simplified nonlinear model given by a set of nonlinear ordinary differential equations, which describes the evolution of a strip camber between two roll stands in hot rolling mills. The proposed model is validated by means of a two dimensional finite element model of the strip with roll stand. Using the property of flatness, the derivation of optimal trajectories and a model predictive control are formulated as a quadratic program. This allows us to satisfy the process requirements and restrictions, which are validated by means of simulation in the co-simulation environment consisting of HOTINT and MATLAB.     

The effect of Mg(NO<Subscript>3</Subscript>)<Subscript>2</Subscript> addition on the formation of AlN nanowire by direct nitridation

In this study AlN nanowire was produced via direct nitridation (DN) method. In order to investigate the effect of nitridation on the formation of nanowire, elemental aluminum powder and ammonium chloride (NH₄Cl) mixture was prepared with and without the addition of minor amount (0.5 wt%) of magnesium nitrate (Mg(NO₃)₂). The experiments were performed in a conventional electric resistance furnace coupled with a horizontal stainless-steel tube. Nitridation was carried out at 800–1000 °C for 2 h in N₂ atmosphere. Differential scanning calorimetry and thermal gravimetric analyses were performed to powder mixtures, in order to examine the effect of Mg(NO₃)₂ addition on the morphology of AlN nanowire. X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM) and Energy-dispersive X-ray spectroscopy (EDS) techniques were also performed to identify to formed phases after the DN method. Using this technique, it was shown that with an addition of Mg(NO₃)₂ at 950 °C in N₂ atmosphere a complete transformation to AlN nanowires was achieved having diameters of 40–45 nm.     

Evaluation of the ASTM D7869-13 test method to predict the gloss and color retention of premium architectural finishes-I

A recently developed xenon arc-based accelerated weathering cycle, ASTM D7869-13, has been validated for automotive and aerospace coatings, but its ability to predict the gloss and color retention of premium architectural finishes has not yet been evaluated. We review new weathering data comparing the performance of poly(vinylidene fluoride) (PVDF) architectural finishes in south Florida exposure as well as several accelerated exposure methods including ASTM D7869-13. ASTM D7869 accurately reproduced Florida rank order gloss and color retention trends for coatings made with PVDF-acrylic blends and inorganic pigments, as well as the gloss and color changes seen in Florida for 70% PVDF masstone coatings made with a number of single organic pigments. However, the D7869 cycle has difficulty predicting the rank order of rutile TiO₂ grades for the gloss retention of PVDF coatings in Florida, as well as the magnitude and direction of color fade from organic pigment degradation in organic pigment/inorganic pigment blends. One open question that remains is whether the ASTM D7869 cycle might have some utility for industry standard or specification purposes, if the test is limited to specific reference colors or more ideally to specific reference pigments.