Phase Stability Study on the Remelting Reaction in Ca2SiO4 Solid Solutions

A pseudobinary phase equilibrium diagram has been established for the P₂O₅-bearing Ca₂SiO₄-CaFe₄O₇ system to confirm the occurrence of remelting reaction in α-Ca₂SiO₄ solid solutions (C₂S(ss)). The reaction started at 1290°C immediately after the α-to-α'_H transition and finished at 1145°C. The reaction products were made up of about 1 wt% of liquid and 99 wt% of solid α'_H-C₂S(ss). The liquid exsolved at 1290°C was rich in Fe₂O₃, consisting of about 30 wt% of Ca₂SiO₄ and 70 wt% of CaFe₄O₇. The liquid coexisting with α-C₂S(ss) precipitated new α'-phase crystals in association with the remelting reaction.     

The Effects of Fluorescent Substances on the Photofading of Colours.

A fluorescent whitening agent of a pyrazoline type (FJ was found to accelerate the fading of Methyl Violet (MV) on irradiation at 366 nm in a film of polyacrylonitrile, while MV quenched the fading of F. In copolymers of acrylonitrile with vinyl acetate or acrylamide, the fading rates of F and MV as well as the acceleration of the fading of MV by F decreased with increasing comonomer content. The accelerated fading of MV by Fw was also observed in a commercial acrylic fibre, Vonnel W, on irradiation at 330 nm, while F had little effect on the decay of MV in this fibre in visible light. The fastness on polymers of MV exposed to a xenon lamp was in the following order: polyacrylonitrile<gelatin<cellulose acetate<acrylonitrile-vinyl acetate copolymer.     

Visualization and Quantitative Detection of Friction Force by Self‐Organized Organic Layered Composites

Visualization and quantitative detection of external stimuli are significant challenges in materials science. Quantitative detection of friction force, a mechanical stress, is not easily achieved using conventional stimuli‐responsive materials. Here, the quantitative detection of friction force is reported, such as the strength and accumulated ammount, from the visible color of organic layered composites consisting of polydiacetylene (PDA) and organic amines without an excitation light source. The composites of the layered diacetylene monomer crystal and interlayer organic amine are synthesized through self‐organization from the precursor solution. After topochemical polymerization, the layered composites based on PDA show tunable temperature‐responsive and mechanoresponsive color‐change properties depending on the types of interlayer amines. The layered composites are homogeneously coated on a filter paper. The change in color of the paper is quantitatively used to visualize the strength and accumulated amount of the applied friction force. Furthermore, writing pressure is measured by friction force using the paper device.     

Man-machine interface for modular robot systems

A modular robot is composed of multiple modules, each comprising a sensor, an actuator, and a control system. Each module accumulates information about its own sensor, actuator, and connections to other modules, as well as communication information between adjoining modules. The user obtains this information via an interface, and can thus recognize the state of the robot and issue commands. However, when the number of modules becomes large, the amount of information sent from the modules becomes too much for the user to deal with effectively. Naturally, it also becomes more difficult for the user to issue commands to the modular robot as the number of modules increases. In this study, we developed an interface to present, in a simple manner, information aggregated in a certain module from other modules, and we examined its effectiveness in a modular robot composed of these modules.     

Autonomous reconfiguration of robot shape by using Q-learning

A modular robot can be built with a shape and function that matches the working environment. We developed a four-arm modular robot system which can be configured in a planar structure. A learning mechanism is incorporated in each module constituting the robot. We aim to control the overall shape of the robot by an accumulation of the autonomous actions resulting from the individual learning functions. Considering that the overall shape of a modular robot depends on the learning conditions in each module, this control method can be treated as a dispersion control learning method. The learning object is cooperative motion between adjacent modules. The learning process proceeds based on Q-learning by trial and error. We confirmed the effectiveness of the proposed technique by computer simulation.     

Internal stress of epoxy resin modified with acrylic core-shell particles containing functional groups prepared by seeded emulsion polymerization

In order to reduce the internal stress in a cured epoxy resin, submicrometer-sized poly(butyl acrylate) (PBA)/poly(methyl methacrylate) (PMMA) core-shell particles having cross-links were dispersed in the resin prior to curing. For the introduction of cross-links, monoethylene glycol dimethacrylate or glycidyl methacrylate monomer was copolymerized. Cross-links in the PBA core reduced the shrinkage of the cured epoxy resin, and cross-links at the PMMA shell produced a strong interaction with the epoxy matrix. The internal stress was reduced effectively by the introduction of cross-links.     

Structure and Microtexture Changes in Phosphorous-Bearing Ca2SiO4 Solid Solutions

The crystal structure and microtexture of P-bearing Ca₂SiO₄solid solutions (C₂S( ss )) were studied as a function of x = P/(Si + P) ranging from 0.085 to 0.398. All the samples were prepared at the stable-temperature region of the α' _l -phase and quenched in air. The structures were described in terms of the orthohexagonal or hexagonal cell of the former α-phase. The crystal with x = 0.085 was composed entirely of the orthorhombic α' _l -phase, the modulation wavelength of which was N = 3 along the c -axis. With x = 0.118 and 0.156, the crystal grains were made up of both α' _l and incommensurate orthorhombic phases. The volume fraction of the α' _l -phase decreased with increasing x . With x = 0.197, the crystal was made up exclusively of the incommensurate phase, with the modulation wave vector k given by (1/ N ) a^*+ c^*. A good correlation N = 4.370 – 2.50 x was observed between N (3.75 ≤ N ≤ 4.09) and x (0.118 ≤ x ≤ 0.250). The crystal with x = 0.3.98 consisted of a single hexagonal phase. The modulation wavelength was N = 2 along the a-axis and N = 3 along the c -axis.     

Novel carboxyl functional spherical electromagnetic polypyrrole nanocomposite polymer particles with good magnetic and conducting properties

Magnetic conducting nanoparticles with reactive functional groups are attractive materials for applications in electromagnetic interference shielding, magneto‐optical storage, biomedical sensing, gas and humidity sensors, flexible electronics etc. The objective of this work was to prepare carboxyl functionalized polypyrrole (PPy) nanocomposite particles having good magnetic properties. Electromagnetic PPy nanostructures, abbreviated as PPy/γ‐Fe₂O₃, were first prepared by a chemical one‐step method. In this reaction process FeCl₃ is used as an oxidant for the polymerization of pyrrole and as a source of Fe³⁺ for the formation of γ‐Fe₂O₃. The formation of γ‐Fe₂O₃ is also aided by the initial presence of Fe²⁺, and p‐toluenesulfonic acid (p‐TSA) acted as a dopant. The effects of different stabilizers on the stability and morphology of PPy/γ‐Fe₂O₃ particles were evaluated. The presence of citric acid/sodium dodecyl sulfate during chemical oxidative polymerization produced a relatively stable PPy/γ‐Fe₂O₃ colloidal emulsion. PPy/γ‐Fe₂O₃/poly(methylmethacrylate‐methacrylic acid) (PPy/γ‐Fe₂O₃/P(MMA‐MAA)) nanocomposite polymer particles were then prepared by the seeded copolymerization of MMA and MAA in the presence of magnetic PPy/γ‐Fe₂O₃ nanocomposite seed particles. The structure and morphology of the prepared nanocomposites were confirmed by different instrumental techniques such as Fourier transform IR spectroscopy, UV?visible spectroscopy, electron micrographs, XRD and X‐ray photoelectron spectroscopy. The electrical and magnetic properties were also investigated. The carboxyl functional electromagnetic PPy nanocomposite polymer particles should be useful for the immobilization of drugs or biomolecules to design electrically stimulated drug delivery systems for modulating the activities of nerve, cardiac, skeletal muscle and bone cells. © 2016 Society of Chemical Industry