Anatase-Type TiO2 and ZrO2-Doped TiO2 Directly Formed from Titanium(III) Sulfate Solution by Thermal Hydrolysis: Effect of the Presence of Ammonium Peroxodisulfate on their Formation and Properties

Anatase-type TiO₂ powder containing sulfur with absorption in the visible region was directly formed as particles with crystallite in the range 15–88 nm by thermal hydrolysis of titanium(III) sulfate (Ti₂(SO₄)₃) solution at 100°–240°C. Because of the presence of ammonium peroxodisulfate ((NH₄)₂S₂O₈), the yield of anatase-type TiO₂ from Ti₂(SO₄)₃ solution was accelerated, and anatase with fine crystallite was formed. Anatase-type TiO₂ doped with ZrO₂ up to 9.8 mol% was directly precipitated as nanometer-sized particles from the acidic precursor solutions of Ti₂(SO₄)₃ and zirconium sulfate in the presence and the absence of (NH₄)₂S₂O₈ by simultaneous hydrolysis under hydrothermal conditions at 200°C. By doping ZrO₂ into TiO₂ and with increasing ZrO₂ content, the crystallite size of anatase was decreased, and the anatase-to-rutile phase transformation was retarded as much as 200°C. The anatase-type structure of ZrO₂-doped TiO₂ was maintained after heating at 1000°C for 1 h. The favorable effect of doping ZrO₂ to anatase-type TiO₂ on the photocatalytic activity was observed.     

Relation between crystal structure and lattice oxygen content of sintered reaction-bonded silicon nitride

When reaction-bonded silicon nitride containing MgO/Y₂O₃ additives is sintered at three different temperatures to form sintered reaction-bonded silicon nitride (SRBSN), the thermal conductivity increases with sintering temperature. The β-Si₃N₄ (silicon nitride) crystals of SRBSN ceramics were synthesized and characterized to investigate the relation between the crystal structure and the lattice oxygen content. The hot-gas extraction measurement result and the crystal structure obtained using Rietveld analysis suggested that the unit cell size of the β-Si₃N₄ crystal increases with the decrease in the lattice oxygen content. This result is reasonable considering that the lattice oxygen with the smaller covalent radius substitutes nitrogen with the larger one in the β-Si₃N₄ crystals. The lattice oxygen content decreased with increasing sintering temperature which also correlated with increase in thermal conductivity. Moreover, it is noteworthy from the viewpoint that it may be possible to apply the lattice constant analysis for the nondestructive and simple measurement of the lattice oxygen content that deteriorates the thermal conductivity of the β-Si₃N₄ ceramics.     

A new refining process for iron oxide using iron ore and its application to hard ferrites

Kawasaki Steel Corporation and Kawatetsu Mining Co., Ltd. have developed a new refining process to extract iron oxide from iron ore to meet the increase in demand for iron oxide for high- grade hard ferrites. This article discusses the quality of iron oxides and the characteristics of the hard ferrite magnets produced from them.     

Construction of living cellular automata using the Physarum plasmodium

The plasmodium of Physarum polycephalum is a unicellular and multinuclear giant amoeba that has an amorphous cell body. To clearly observe how the plasmodium makes decisions in its motile and exploratory behaviours, we developed a new experimental system to pseudo-discretize the motility of the organism. In our experimental space that has agar surfaces arranged in a two-dimensional lattice, the continuous and omnidirectional movement of the plasmodium was limited to the stepwise one, and the direction of the locomotion was also limited to four neighbours. In such an experimental system, a cellular automata-like system was constructed using the living cell. We further analysed the exploratory behaviours of the plasmodium by duplicating the experimental results in the simulation models of cellular automata. As a result, it was revealed that the behaviours of the plasmodium are not reproduced by only local state transition rules; and for the reproduction, a kind of historical rule setting is needed.     

Cost-Efficient Traffic Aggregation Employing Cross-Layer Shared Protection

Shared protection/restoration is a promising solution for reducing protection resources and is supported at each layer of the current multi-layer networks. Software-defined networking is expected to reduce equipment cost as well as operational cost by orchestrating these shared protection functionalities. However, although protection resource sharing improves link utilization, it sometimes increases the required equipment. Meanwhile, traffic re-aggregation at each layer is an important technique for low volume traffic to utilize the underlying link capacity more efficiently, but re-aggregation also makes it difficult to share protection resources with traffic at lower layers. In this paper, we present multi-layer network design strategy and method that reduce equipment cost by means of both traffic re-aggregation at each layer and protection resource sharing among multiple service traffic at different layers. The strategy first prioritizes traffic re-aggregation at each layer, and then maximally delegates shared protection to lower layers as long as it does not increase the required capacity at the lower layer. Evaluation results from the example three-layer networks confirm that the proposed method can effectively reduce equipment cost compared to the conventional design method. Cost reduction is achieved by leveraging shared protection functions at multiple layers.     

Set-based particle swarm optimization with status memory for knapsack problem

Set-based particle swarm optimization (S-PSO) operates on discrete space. S-PSO can solve combinatorial optimization problem with high quality and is successful to apply to the large-scale problem. In S-PSO, a velocity is a set with possibility and a position is a candidate solution. In this paper, we present a novel algorithm of set-based particle swarm optimization with status memory (S-PSOSM) to decide the position based on the previous position for solving knapsack problem. Some operators are redefined for S-PSOSM. S-PSOSM is a simple algorithm because the state of probability reduces. In addition, the weight of S-PSOSM is discussed. S-PSOSM shows high qualities in experimental results.