Carboxymethyl Kefiran: Preparation and Viscometric Properties

Carboxymethyl (CM-) kefiran was prepared with monochloroacetic acid in isopropyl alcohol at 30, 40 and 50°C for 4 and 24 hr. Resulting CM-kefiran varied in degree of substitution (0.73-0.89), molecular weight (5.0-7.0 × 10⁵) and viscosity (4.5-14.5 cP in 0.5% aqueous solution) depending on the conditions. Carboxymethylation resulted in a maximum fourteenfold increase in viscosity. ¹³C-NMR spectra of CM-kefiran indicated C-6 of native kefiran was preferentially substituted with CM-groups.     

Basic Design Method for SPMSM Based on Air‐Gap Magnetic Flux Density Distribution Focusing on Image Magnetic Pole

This paper presents a basic design method for the surface‐mounted permanent magnet synchronous motor (SPMSM) for both distributed and concentrated windings. The design is based on the air‐gap magnetic flux density distribution focusing on the image magnetic pole. The calculus equation of the air‐gap magnetic flux density distribution is analytically derived by supposing the magnetic pole is located on the magnet surface and image planes. In this study, a three‐phase and double‐layer stator winding SPMSM that has a linear demagnetizing characteristic magnet, such as a ferrite or rare‐earth magnet is considered. From the required specifications and design conditions, the design target values of the parameters that appear in the voltages equations of the d–q axis coordinate system are calculated. Then, the relational equations for the torque constant, d‐axis inductance, copper loss, and the maximum current density are presented as a function of three design parameters under i_d = 0 control. They are the stator stack length, the number of coil turns in series in a phase, and the slot bottom length. Hence, this approach reduces the SPMSM basic design to the problem with these design parameters has to be solved. The proposed method makes it possible to address the concentrated winding as a special case of the distributed winding. The FEA results confirm the validity of the proposed basic design method for both distributed and concentrated windings.     

Development of Corrosion‐Resistant Pressure Sensor with Semiconductor Strain Sensor

In automotive and industrial fields, pressure sensors are a key component for precisely controlling the mechanical systems. Conventional micro electro mechanical system (MEMS)‐based pressure sensors have an advantage in noise resistance, because both strain gauges and control circuits are integrated in one chip. However, the MEMS‐based pressure sensors are generally fabricated on an Si substrate, and have a low stability against various active gases. Thus, we have newly proposed a pressure sensor which consists of an Si‐based strain sensor set on a stainless steel diaphragm with a high stability against the active gases. The key technology is that a Koval plate is inserted between the strain sensor and the stainless steel diaphragm, for preventing the breakage or the delamination of the strain sensor at the bonding interface due to a difference in thermal expansion. Structure of the sensor including the shape and the size of Koval plate and the assembly position of the strain sensor were designed using structural simulation and experiments. Eventually, the 2.8 mm wide and 0.17 mm thick Koval beam was bridged on the stainless steel diaphragm for efficiently transmitting the diaphragm deformation to the strain sensor. The strain sensor was assembled at the edge of Koval beam with a glass bonding technique. Consequently, the developed pressure sensor has achieved a small dispersion of less than 1% F. S. in a temperature range from 0 °C to 85 °C.     

Judging Degradation of Lithium‐Ion Batteries Using a Real‐Time Capacitance Measurement

A novel method was proposed to judge degradation/health of lithium‐ion batteries (LIBs) using the capacitance that was estimated from the real‐time voltage and current characteristics of the batteries. It is thought that the capacitance of LIBs decreases with degradation because of undesirable components formed on the electrodes that are the main cause of the degradation. As the LIBs are active, the capacitance was evaluated from the differential equation, ?Q /?v = I /(?v /?t ) = i /(dv /dt ), using the voltage and current characteristics during the charging or discharging. The capacitances of the commercial LIBs with different SOHs; 100%, 92%, and 88% were estimated during the charging and discharging using the equation. The average capacitance in the specific voltage region of the batteries was directly proportional to the state of health. Therefore, the proposed measurement is thought to be a useful method for judging degradation of LIBs.     

Reducing Acoustic Noise of Axial‐Gap SRMs by Decreasing Axial Electromagnetic Force Ripple

Switched reluctance (SR) motors are motors that utilize the reluctance torque originating in the magnetic saliency between the stator and the rotor, which are made up of an electromagnetic steel sheet and windings without a permanent magnet. Because of their robustness and simple structure, SR motors are suited for use as the in‐wheel motor for traction motors of vehicles. In a flat space such as is present in in‐wheel motors, the axial‐gap structure has an advantage compared with the conventional radial‐gap structure for the space factor of a motor. An axial‐gap in‐wheel SR motor was tested in a microbus, and the bus could be successfully driven. The test results regarding the motor performance were satisfactory. However, the motor emits a loud sound. The acoustic noise of the axial‐gap SR motor is mainly caused by the axial electromagnetic force. This paper presents a method of reducing acoustic noise that is based on a model of the electromagnetic force on the axial‐gap SR motor.     

Estimation and Kinetic Modeling of Human Arm using Wearable Robot Arm

This paper describes an estimation method for the physical parameters of human arms. The parameters are used in the medical and kinematic analysis fields. Personal differences are important, but some of the conventional methods do not consider personal differences pertaining to inertia in viscoelasticity muscular strength measurements. The remaining conventional methods that consider personal differences require precise measurement devices. The proposed method realizes kinetics modeling and identification of the friction and inertia including the off‐diagonal parameters of human arms by using wearable robots. First, wearable robots are multi‐input devices. In addition, the actuators of wearable robots can be located near human joints and can input M‐sequence torque. Therefore, wearable robots can input signals having a high signal‐to‐noise ratio and ensuring persistently exciting characteristics in each human joint. By employing multi‐input characteristics, the proposed method can reduce patients’ burden by shortening the amount of time for estimation. In addition, we verify the accuracy of the estimated parameters by comparing the responses of the actual machine with those obtained by simulation.     

城市内部结构和人口密度对地表温度空间变化的影响——以东京新宿区为例

随着城市化进程的加快和人口的快速增长,城市空间内部格局正发生变化,城市热岛效应不断加剧。本研究旨在根据建筑、人口与地表热环境的关系来寻求可持续发展。与其他研究相比,本文采用了东京新宿区的机载热红外图像、机载激光雷达数据、建筑物矢量数据和人口普查数据等新颖数据,且最大创新点在于对建筑密度、平均高度、平均地表温度(Land Surface Temperature, LST)和人口密度之间进行的定量分析。结果显示,平均LST与建筑密度的相关性最大(r=0.6718),其次是平均LST与人口密度的相关性(r=0.6050);建筑密度与人口密度呈正相关(r=0.4949),平均LST与建筑物平均高度呈负相关(r=-0.3814)。经研究可知,通过合理规划城市内部结构有望为减弱城市热岛效应和实现环境可持续发展提供参考。     

Failure diagnosis of a servovalve by neural networks with new learning algorithm and structure analysis

This paper considers a failure diagnosis of a pneumatic servovalve used in automated production systems. The valve is monitored by an accelerometer. Six parameters characterizing the vibration data are extracted, and fed into neural networks to solve four types of diagnosis problems. A conjugate gradient followed by a variable metric method is demonstrated as an effective learning algorithm. Neural network structures are analysed through Boolean expressions summarizing network simulation results for given learning patterns. The neural networks are found to utilize majority voting mechanisms. Irrelevant neurons can be identified and removed without degrading the diagnosis performance.     

Curdlan Properties for Application in Fat Mimetics for Meat Products

Gelling characteristics and viscoelastic properties of aqueous suspensions of curdlan were investigated by dynamic viscoelasticity measurements. The mechanical spectrum of the suspension was similar to that of weak gels, suggesting the suspension has a well-regulated particle-alignment with yield stress. Curdlan reached the highest moisture absorption rate within the temperature range in which the most significant moisture loss of meat occurs. These results suggest that curdlan could be an effective main ingredient in fat mimetics for meat products. Nonfat sausages using the curd lan-based fat mimetics were prepared and evaluated by a creep test and indicated curdlan was effective as a fat re-placer in such systems.