New data on phase equilibria in the Nb-rich region of the Nb-B system

The currently accepted Nb-B phase diagram shows Nb_ss (solid solution), Nb₃B₂, NbB, Nb₅B₆, Nb₃B₄, NbB₂, B, and liquid L as the stable phases in this system. There is a general agreement in the literature about the stability of the NbB, Nb₃B₄, and NbB₂ phases. However, the stability of Nb₃B₂, Nb₅B₆, and Nb₂B₃ phases is arguable. The aim of this work was to reevaluate the phase equilibria in the Nb-rich region (0-50at.% B) of the Nb-B system. The alloys were arc melted from high purity materials and heat-treated at 1700 °C under high vacuum. The samples were characterized by scanning electron microscopy/back-scattered electron image (SEM/BSE) and x-ray diffraction (XRD). The most important findings were: (1) no liquid formation was observed during heat-treatments of the alloys at 1700 °C; (2) the eutectic reaction in the Nb-rich region is L ↔ Nb_ss+ NbB with liquid eutectic composition close to 16 at.%B; and (3) the Nb₃B₂-phase is formed through the peritectoid reaction Nb_ss+ NbB ↔ Nb₃B₂. These results support the phase diagram proposed by Rudy [1969 Rud] for the Nb-rich region, which is not in agreement with the currently accepted Nb-B phase diagram.     

Investigation and design of a new shock absorbing device that cooperates between two colliding objects

This paper deals with a new type of shock absorbing device that cooperates between two colliding objects. The new device utilizes a four-bar-chain-like articulated mechanism with some possible actuations. The devices are assumed to be deployed in the pre-crash phase (by sensing and identifying unavoidable collisions) so as to provide an extended deformable region between the two objects. Moreover, by functioning like a four-bar-chain mechanism, they produce a repulsive effect by pushing each other and sliding in the opposite lateral direction. To investigate the capacity of the proposed articulated shock absorbing mechanism, a standard numerical optimization technique called SQP and a new optimization technique called ALPSO are applied. ALPSO is an attractive method for solving multimodal optimization problems based on Particle Swarm Optimization and constraint treatment using an Augmented Lagrange Method. We demonstrate ALPSO and show its applicability to this problem. The optimization process automatically determines the mode of the operation and gives an estimation of the development potential of the new device. This paper was presented at the 4th Asian Conference on Multibody Dynamics(ACMD2008), Jeju, Korea, August 20–23, 2008. Mr. Atsushi Kawaguchi received his B.S. and M.S. degrees in Engineering from Hiroshima University in 2001 and 2003, respectively. Mr. Kawaguchi is currently a researcher at the Toyota Central R&D Labs., Inc. in Aichi, Japan. His research interests are in the area of engine vibration analysis, multibody dynamics, and vehicle safety. Dr.-Ing Kai Sedlaczek studied Mechanical Engineering at the University of Wisconsin in Madison and at the University of Stuttgart, where he joined the Institute of Engineering and Computational Mechanics in 2002. There, he received his doctorate in Mechanical Engineering in 2007. His main fields of interest are multibody systems, optimization and vehicle dynamics. Dr. Atsushi Kawamoto received an M.Sc. degree from the department of Mechanical Engineering, Nagoya University in 1995. He then went on to receive his Ph.D. degree from the department of Mathematics, Technical University of Denmark in 2005. Dr. Kawamoto is currently a researcher at the Toyota Central R&D Labs., Inc. in Aichi, Japan. Dr. Kawamoto’s research interest areas are in topology and shape optimization, multibody dynamics and multiphysics. Prof. Peter Eberhard received his Dipl.-Ing. in Mechanical Engineering, his Dr.-Ing. and his Habilitation in Mechanics from the University of Stuttgart in Germany. In 2000 he was appointed as professor of Mechanics and System Dynamics at the University of Erlangen-Nuremberg before he became full professor and director of the Institute of Engineering and Computational Mechanics at the University of Stuttgart in 2002. In 2000 he received the Richard-von-Mises award and in 2007 an Honorary Professorship at the Nanjing University of Science and Technology, P.R. China. Prof. Eberhard’s research interests include multibody dynamics, contact mechanics, mechatronics, optimization and biomechanics.     

Spring mechanics of {{alpha}}-helical polypeptide

To design protein- and polymer-based micro-machineries, it isimportant to understand the mechanical properties of basic structuralelements such as the     

A study of the merits of a battery combined photovoltaic generation system for a residential house

In this paper we examine the merits that a practical photovoltaic system combining photovoltaic generation with storage batteries would provide if used in ordinary residences. Various configurations and operation methods could be envisaged for such a system. In this research we examined the optimal battery capacity, operation methods, and economic effects for a system emphasizing an economical merit for the user. We first calculated the hourly amount of photovoltaic generated electricity each month, and used data on average load patterns from actual measurements to calculate battery capacity. Next, taking battery capacity and photovoltaic module capacity/price as parameters, we calculated and evaluated the economic merit for ordinary residences. The result showed that the optimal battery capacity for combination with 3‐ or 5‐kW photovoltaic generation is around 10 kWh, and that a combined system provides a merit even though it entails higher photovoltaic module costs than the use of photovoltaic generation alone. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 147(4): 20–31, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10302     

Temperature effect on single bubble rise characteristics in stagnant distilled water

Rise characteristics of spherical and ellipsoidal bubbles in normal- and high-temperature distilled water were visually observed. In the high-temperature experiments, the measured results of the rise velocity of a single bubble and the existence of rise path oscillation roughly agreed with the correlations for the bubbles in contaminated liquid. Also, applicability of an available correlation for the frequency of rise path oscillation was confirmed and a new correlation was developed to evaluate the amplitude of oscillation. It is expected that these results are to contribute to the further improvement of the prediction methods of multidimensional void distribution.     

Simplified method for estimation of composition of alginates by FTIR

A modified method of preparing highly purified polymannuronic acid and polyguluronic acid was developed wherein acid hydrolysis was carried out using oxalic acid and separation was made using the difference of solubility with pH value. The simplified method using FTIR measurement to estimate the M/G ratio of alginate was investigated using Ca or Mn salts of alginate. The developed method appears to offer enhanced accuracy compared to that of previous techniques. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1372–1377, 2004     

A kinetic model for co-oxidation of β-carotene with oleic acid

Oxidation experiments with β-carotene in a lipid solution were conducted under various conditions of temperature, oxygen composition, and lipid content. The experimental results were compared with those using n-decane reported previously. Under all conditions, the oxidation rate in oleic acid was faster than that in n-decane. A novel kinetic model for the co-oxidation of carotene with a lipid was proposed based on the reaction mechanism, which consisted of the oxidation of carotene, the oxidation of oleic acid, and the cross-reaction of carotene with oleic acid. The model quantitatively described the oxidation behavior of carotene over a wide range of temperatures, oxygen compositions, and lipid contents.     

Novel porous TiO2 glass-ceramics with highly photocatalytic ability

A porous TiO₂ glass-ceramics with high photo-oxidative activity was successfully obtained from the SiO₂–Al₂O₃–B₂O₃–CaO–TiO₂ glass system. Rutile-type TiO₂ was observed in the crystallization temperature range of 973–1173 K. The band gap of the glass-ceramics coincided approximately with that of rutile-type TiO₂. The photocatalytic activity of this glass-ceramics was about four times larger than that of a TiO₂-coated photocatalyst fabricated by the sol–gel process. Furthermore, as this porous TiO₂ glass-ceramics contained TiO₂ in composition form, it could prevent peeling of the TiO₂ from the substrate. As well, this glass-ceramics can be easily shaped into sheets, tubes, rods, etc.     

Featureless robot navigation using optical flow

In this paper, we aim to develop an algorithm for featureless navigation of an autonomous robot using optical flow observed through a vision system mounted on a mobile robot. Furthermore, we show that this optical flow observed from a mobile robot for navigation of it is also used in the construction of environmental maps. Our algorithm first detects an area corresponding to the dominant plane from a sequence of images employing optical flow and, second, backprojects the dominant plane to the environment for the construction of the environmental map. Moreover, our algorithm estimates ego-motion of the mobile robot using projected optical flow. The planar area detection by our method does not require any physical assumptions concerning the robot motion of any camera calibration. Therefore, our algorithm allows obstacles to be detected without using any feature in the environment and any heuristics rule. We show the results of the construction of an environmental map using the mobile robot.