Development of the visible light communication device for swarm using nonlinear synchronization

This paper describes development of a visible light 4 Pulse position modulation (4PPM) data communication device for underwater swarms using a nonlinear synchronizing system. SWARM—a group robot that uses intelligence as a group—do as ants and bees, is expected to be useful for marine resource exploration. Specifically, numerous SWARMs will be grouped to explore marine resources efficiently. An important difficulty is the change in electronic circuit characteristics because of high water pressure in the deep sea. Development of small and simple underwater SWARM communication devices must eliminate this problem without using large pressure-proof containers. As described herein, we considered nonlinear synchronizing systems as effective because they can be synchronized even if system time constants differ. Such systems resemble the glow mechanism used by fireflies. They have individuality, but they flash synchronously when in a group. We developed a visible light communication device using this nonlinear synchronization system based on the firefly concept. Test results confirmed that they are synchronized even if a time constant difference exists between them. Furthermore, we achieved 4PPM data communication using the nonlinear synchronization signal as a communication clock.     

The extraction of divalent cobalt,copper, zinc and cadmium from hydrochloric acid solutions by tri-n-butyl phosphate

The partition of divalent cobalt, copper, zinc and cadmium between hydrochloric acid solutions and solutions of tri-n-butyl phosphate (TBP) in benzene or kerosene has been investigated under different conditions. Further the absorption spectra of both the aqueous and organic phases have been studied, and the infrared spectra of the organic phases have been examined. It was found that the order of the extraction efficiency of TBP for divalent metalsis Zu > Cd > Cu > Co for [HCl]_aq < 8M and Zn > Cd > Co > Cu for [HCl]_aq > 8M.     

Characterization and transport properties of a novel aliphatic polyamide with an ethyl branch

The CO₂ gas and water vapor transport properties of a novel aliphatic polyamide with an ethyl branch were investigated. The polymer was characterized with density measurements, differential scanning calorimetry, thermogravimetric analysis, and wide‐angle X‐ray diffraction analyses, and the amorphous and glassy nature of the polymer at the ambient temperature were confirmed. The CO₂ sorption isotherm of the polymer appeared to obey the dual‐mode sorption isotherm, which was characteristic of the glassy state. The water vapor sorption below a relative humidity of 0.4 or 0.5 was explained in terms of the Brunauer–Emmett–Teller sorption mechanism, whereas that at a high relative humidity demonstrated a dissolution type of water vapor into the polyamide. The permeability coefficients of He, CO₂, O₂, and N₂ gases through the membrane were as follows: P(He) > P(CO₂) > P(O₂) > P(N₂). The novel polyamide membrane was more permeable to CO₂, O₂, and N₂ gases than nylon 6 and nylon 66 membranes, containing a crystalline and hydrogen‐bonding nature. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1955–1960, 2005     

Hydrocracking of diphenylmethane: Roles of H2S and pyrrhotite

To define the roles of H₂S and pyrrhotite in high temperatures employed for normal coal liquefaction, diphenylmethane hydrocracking with H₂ and H₂-H₂S was carried out with and without pyrrhotite. H₂S promotes diphenylmethane hydrocracking with H₂ both in the presence and absence of pyrrhotite, and the reaction is dependent upon the H₂S pressure in both instances. It is also dependent on the H₂ pressure when pyrrhotite is present. The results are interpreted in terms of H₂S acting as a hydrogen transfer catalyst.     

Solute atmosphere around an edge dislocation in Al-based ternary alloys

We evaluated the solute atmosphere around a moving dislocation and the dragging stress due to the atmosphere in binary and ternary Al-based alloys in terms of a chemical potential gradient by modifying the method proposed by Yoshinaga et al. In ternary alloys, we analyzed formation of the complex solute atmosphere around a straight edge dislocation and the dragging stress in terms of a misfit parameter of a solute element (positive or negative) and an interaction parameter between solute elements (attractive or repulsive).     

Improvement of creep rupture strength of welded joints in 9Cr Mo V Nb steels (ASTM A387-Gr.91)

Summary

This paper describes efforts to fabricate explosively welded Al/Cu clad through insertion of a Cu intermediate plate between the Al driver and Cu base plates. In explosively welded Al/Cu clad fabricated by the conventional method, generation of an excess reacted interfacial zone causes degradation of bonding properties. Application of a Cu intermediate plate is effective as a means of reducing the energy dissipated by collision. The effect of the kinetic energy lost by collision on the thickness of the reacted interfacial zone and on the bond strength are examined in experiments with stainless steel. Efforts are made to fabricate Al/Cu conductive transition joints of commercial size with a Cu intermediate plate. The bonding properties obtained are better than those obtained by the conventional method.     

Multiferroic nanocomposite fabrication via liquid phase using anodic alumina template

We report a novel and inexpensive fabrication process of multiferroic nanocomposite via liquid phase using an anodic alumina template. The sol-gel spin-coating technique was used to coat the template with ferrimagnetic CoFe₂O₄. By dissolving the template with NaOH aqueous solution, a unique nanotube array structure of CoFe₂O₄ was obtained. The CoFe₂O₄ nanotube arrays were filled with, and sandwiched in, ferroelectric BaTiO₃ layers by a sol-gel spin-coating method to obtain the composite. Its multiferroicity was confirmed by measuring the magnetic and dielectric hysteresis loops.     

Relationship between Rice Flour Particle Sizes and Expansion Ratio of Pure Rice Bread

We examined a method to produce bread from crystalline rice flour without using thickening agents such as gluten, polysaccharide thickening, and amorphous rice flour. Rice grains were pulverized by a jet mill to produce flour. Samples of rice flours of various particle size distributions were prepared by using a size shifter. The degree of starch damage and the dynamic viscoelasticity of rice batter were measured in this work. We also baked bread of the flour of each size distribution to study processability for making bread. The batter made by the pulverized flour of rice particle size ranging from 75 to 106 μm had the highest expansion ratio and a good processability for baking breads compared to other particle size batters. The rice bread with high expansion ratio was produced by controlling particle size of crystalline rice flour without using thickening agents.     

Experimental Study of DBD Plasma Actuator with Combination of AC and Nanosecond Pulse Voltage

In the last decade, dielectric barrier discharge (DBD) plasma actuators using a combination voltage of AC and a nanosecond pulse have been studied. The combined‐voltage‐driven plasma actuator increases the body force effect, including wall jet and flow suction, by overlapping the nanosecond pulse voltage, while the DBD plasma actuator driven by nanosecond pulses is a flow control actuator generating compression waves due to pulse heating, which makes it possible to supply an active flow control at a high‐speed flow, reported as up to Mach 0.7. In this study, a DBD plasma actuator driven by a combination voltage of sinusoidal AC and nanosecond pulse was experimentally investigated. The time‐averaged net thrust and cycle‐averaged power consumption of the actuator were characterized by using an electrical weight balance and the charge‐voltage cycle of a DBD plasma actuator, respectively. The plasma actuator thrust driven with the combination voltage showed increased thrust with increasing pulse repetition rate. The energy consumption of the actuator was controlled by varying the AC phase when the nanosecond pulse was applied. Therefore, the thrust and power consumption in the actuator were almost independently controlled by the pulse repetition rate and the pulse imposed phase.