Phase separation mechanism during membrane formation by dry‐cast process

Phase separation mechanisms during the membrane formation by dry‐cast process were investigated by light scattering in the cellulose acetate/dimethylformamide (DMF)/2‐methyl‐2,4‐pentanediol system. Phase separation occurred by spinodal decomposition (SD) when paths of the composition changes due to the evaporation of DMF were close to the critical point in the phase diagram. Characteristic properties of the early stage of SD such as an apparent diffusion coefficient and an interface periodic distance were obtained from the Cahn theory. Phase separation occurred by nucleation and growth (NG) when paths of the composition changes were far from the critical point. SEM observation confirmed that the membrane formed by the SD mechanism had interconnected structure, whereas that by the NG mechanism had the closed cell porous structure. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 776–782, 2000     

Optical humidity sensing characteristics of composite thin films of hydrolysed nafion-dye with a terminalN-phenyl group

By using composite films of hydrolysed nafion and dyes having cyanine or triphenyl structures and with a terminal N-phenyl group, an optical humidity sensor has been fabricated. In the reflection mode, the optical intensity of the absorption peaks which depend on the used dyes decreases with relative humidity. The raising and recovery times are less than 1 min. In dry air, the alkyl amine group reacted with SO₃H of hydrolysed nafion and formed a proton additive. Sorption of water molecules induces the deprotonation of the quaternized ammonium group.     

Deep undergroud space—the new frontier

Focusing on Japan's experience, the author addresses the significance of deep underground space use; progress in underground development that now permits full-scale utilization of deep underground space; the forms and facilities of deep underground space use; underground uses based on regional characteristics; new, future forms of underground space use; and technology that will be required to support new forms of underground use.     

Flooding and flow reversal of two-phase annular flow

The flooding and flow reversal conditions of two-phase annular flow are mathematically defined in terms of a characteristic function representing a force balance. Sufficiently below the flooding point in counter-current flow, the interface is smooth and the characteristic equation reduces to the Nusselt relationship. Just below the flooding point and above the flow reversal point in cocurrent flow, the interface is “wavy”, so that the interfacial shear effect plays an important role. The theoretical analysis is compared with experimental results by others. It is suggested that the various length effects which have been experimentally observed may be accounted for by the spatial variation of the droplet entrainment.     

Histochemical evidence of osteoclastic degradation of extracellular matrix in osteolytic metastasis originating from human lung small carcinoma (SBC-5) cells

The aim of this study was to assess the dynamics of osteoclast migration and the degradation of unmineralized extracellular matrix in an osteolytic metastasis by examining a well-standardized lung cancer metastasis model of nude mice. SBC-5 human lung small carcinoma cells were injected into the left cardiac ventricle of 6-week-old BALB/c nu/nu mice under anesthesia. At 25-30 days after injection, the animals were sacrificed and their femora and/or tibiae were removed for histochemical analyses. Metastatic lesions were shown to occupy a considerable area extending from the metaphyses to the bone marrow region. Tartrate resistant acid phosphatase (TRAPase)-positive osteoclasts were found in association with an alkaline phosphatase (ALPase)-positive osteoblastic layer lining the bone surface, but could also be localized in the ALPase-negative stromal tissues that border the tumor nodules. These stromal tissues were markedly positive for osteopontin, and contained a significant number of TRAPase-positive osteoclasts expressing immunoreactivity for CD44. We thus speculated that, mediating its affinity for CD44, osteopontin may serve to facilitate osteoclastic migration after their formation associated with ALPase-positive osteoblasts. We next examined the localization of cathepsin K and matrix metallo-proteinase-9 (MMP-9) in osteoclasts. Osteoclasts adjacent to the bone surfaces were positive for both proteins, whereas those in the stromal tissues in the tumor nests showed only MMP-9 immunoreactivity. Immunoelectron microscopy disclosed the presence of MMP-9 in the Golgi apparatus and in vesicular structures at the baso-lateral cytoplasmic region of the osteoclasts found in the stromal tissue. MMP-9-positive vesicular structures also contained fragmented extracellular materials. Thus, osteoclasts appear to either select an optimized function, namely secreting proteolytic enzymes from ruffled borders during bone resorption, or recognize the surrounding extracellular matrix by mediating osteopontin/CD44 interaction, and internalize the extracellular matrices. Microsc.     

Generation of jumping motion pattern for a hopping robot using genetic algorithm

This paper describes an application of genetic algorithm to generate a jumping motion pattern for a hopping robot. A central pattern generator is used to generate the motion pattern. The tuning parameters of the central pattern generator are regarded as genes and adjusted by the genetic algorithm, so that the hopping robot can jump continuously to the reference height with the minimum force. To realize online tuning of the parameters, new genetic operations such as few individuals, quick estimation, instant selection, and intentional mutation are introduced. The experimental results demonstrate the effectiveness of the proposed scheme. This work was presented, in part, at the Fourth International Symposium on Artificial Life and Robotics, Oita, Japan, January 19–22, 1999     

Design and implementation of robust symmetric attitude controller for ETS-VIII spacecraft

To meet increasing mission requirements, communication satellites are being equipped with large flexible antenna reflectors and solar paddles. A typical such satellite, the Engineering Test Satellite VIII (ETS-VIII) spacecraft, was launched into geostationary orbit by the Japan Aerospace Exploration Agency (JAXA) in December 2006. The main mission of ETS-VIII is to support next-generation mobile digital communications, and for this purpose it is equipped with two large deployable antenna reflectors and a pair of large solar paddles that rotate around the pitch axis. The authors are planning to perform on-orbit attitude control experiments using ETS-VIII at the end of its mission life, aiming to develop a baseline for future controller design for this class of satellite using advanced control theories. This paper proposes two degrees-of-freedom control based on robust direct velocity and displacement feedback as a candidate controller technology. The spacecraft modeling and controller synthesis methods are discussed, and a controller implementation for an on-orbit control experiment is presented with simulation results.     

Self-sensing time-domain reflectometry for detection of the bearing failure of a CFRP laminate fastener hole: effect of peeling of the insulator

Carbon-fiber-reinforced polymer (CFRP) composites are used in aerospace and automobile structures. For many CFRP structures, mechanical metallic fasteners are adopted. In internal structures such as a wing box, damage to CFRP structures around the fastener holes is difficult to see. A simple method of finding damage around fastener holes is thus required for CFRP structures. This study applies self-sensing time-domain reflectometry to detect bearing failure around fastener holes of CFRP structures. In a previous paper, the effect of fasteners was minimized when the micro-strip line (MSL) was placed apart from the fasteners. This study numerically and experimentally investigates the peeling of glass-fiber-reinforced polymer (GFRP) insulator. A bearing failure results in embossing at the edge of a fastener hole. The embossing produces a wedge that causes the peeling of GFRP, generating a gap between the GFRP and CFRP. The gap strongly affects the characteristic impedance of the MSL.     

Analytical solutions to eddy current in carbon fiber-reinforced composites induced by line current

This paper presents analytical solutions to eddy current distribution in carbon fiber-reinforced plastics induced by line current. Derived solutions show that eddy current distribution in unidirectional carbon fiber composite is dependent only on electrical conductivity in the drive current direction when the drive current is directed in the fiber direction or the transverse direction. Moreover, according to the derived analytical solution, skin depth of eddy current depends not only on frequency of drive current but on lift-off and width of the drive current unlike general expression of skin depth. Finally, we discuss improvement of sensitivity of eddy current conductivity sensor using analytical solutions. It is found that analytical solutions can clearly divide effects of magnetic field from drive current and that from eddy current. Sensitivity of eddy current sensor can be improved by 10 times placing pickup coil at region where the effect of magnetic field from eddy current is large.