A design of a miniature ultrasonic pump using a bending disk transducer

If a pipe end is faced at a piston-vibrating surface with a small gap in liquid, the liquid is suctioned into the pipe. The present ultrasonic pump is based on this phenomenon to induce flow. For a low-profile configuration, we introduce a 30-mm-diameter bending disk driven by a ring-shaped PZT element bonded on the back of the disk. The disk vibrator is softly supported by frames via O-rings at its circumference, and is worked at the fundamental resonance frequency of 19 kHz of the bending mode. A pipe is installed perpendicularly to the center of the disk vibrator with a small gap. To improve the pump performance, we seek for the optimum vibration distribution of the disk vibrator. When the thickness around the disk center becomes large, the shape of the vibration distribution near the center approaches to a piston vibrator. If the flatness of the vibration distribution is defined as the vibration amplitude just under the pipe edge divided by the vibration amplitude at the disk center, it is 92.0% for the original bending disk. The flatness of the new design became 98.1% as a result of the optimization of the thickness profile of the disk. The pump pressure became high as the flatness became large when the gap size was small enough. The maximum pump pressure of 20.6 kPa was achieved when the vibration velocity at the disk center was 1.0 m/s and the gap size was 10 μm, while the maximum flow rate of 22.5 ml/min. was obtained with the input electrical power of 3.8 W.     

Analysis of Bed Load Equations and River Bed Level Variations Using Basin-Scale Process-Based Modelling Approach

Bed load transport is a key process in maintaining the dynamically stable channel geometry for restoring the form and function of river ecosystems. Bed load consists of relatively large sediment particles that are moved along the streambed by rolling, sliding or saltation. Currently, various empirical correlations are used to estimate bed load transport rates since no single procedure, whether theoretical or empirical, has yet to be universally accepted as completely satisfactory in this aspect. Bed load particles are primarily sourced from river bed materials or banks. The amount of bed load and its spatial distribution contributes significantly to river bed level changes. Hillslope sediment contribution, mostly available to the river in the form of suspended load, also plays an important role in river bed level changes. This study aims to analyse different bed load equations and the resultant computations of river bed level variations using a process-based sediment dynamic model. Analyses have revealed that different bed load equations were mainly deduced from the concept of relating bed shear stresses to their critical values which are highly factored by the slope gradient, water discharge and particle sizes. In this study, river bed level variations are calculated by estimating total surplus or deficit sediment loads (suspended loads and bed loads) in a channel section. This paper describes the application of different widely used bed load equations, and evaluation of their various parameters and relative performances for a case study area (Abukuma River Basin, Japan) using a basin-scale process-based modelling approach. Relative performances of river bed level simulations obtained by using different bed load equations are also presented. This paper elaborates on the modelling approaches for river bed load and bed level simulations. Although verifications were not done due to unavailability of field data for bed load, qualitative evaluations were conducted vis-à-vis field data on flow and suspended sediment loads as well as the bed loads presented in different past studies.     

A scalable advanced RF IC design‐oriented MOSFET model

This article presents a validation of the EKV3 MOSFET compact model dedicated to the design of analogue/RF ICs using advanced CMOS technology. The EKV3 model is compared with DC, CV and RF measurements up to 20 GHz of a 110 nm CMOS technology. The scaling behaviour over a large range of channel lengths and bias conditions is presented. Long‐channel devices show significant non‐quasi static effects while in short‐channel devices the parasitics modelling is critical. This is illustrated with Y‐parameters and f_t vs. I_D in NMOS and PMOS devices, showing good overall RF modelling abilities of the EKV3 MOSFET model. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2008.     

Construction of a geothermal power generation model based on characteristics of geothermal steam wells and its applications

Electricity generation in geothermal power plants depends on the characteristics of geothermal steam wells. In this research, a geothermal power generation model was constructed based on the characteristics of the steam well, and the generation of electricity was estimated precisely by the constructed model. Many applications of the geothermal power generation model are introduced. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 141(3): 39–49, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10039     

Design of a traveling wave type ultrasonic motor

The purpose of the present paper is to establish a method of design for a traveling wave type ultrasonic motor. This method is based on two models for the ultrasonic motor. A two-dimensional elastic contact model is used for estimating the friction drive between the rotor and vibrator of the motor. Moreover, an electrical equivalent circuit is used to estimate the interaction between the electrical and mechanical parts of the vibrator. The proposed method is applied to the design of a prototype motor. To determine applicability of the method, the load characteristics of the prototype motor are measured. The measured characteristics agree with the required ones which are specified in advance. As a result, the validity of the proposed method is experimentally confirmed     

A simple bidirectional linear microactuator for nanopositioning--the "Baltan" microactuator

A new linear microactuator, using bulk PZT and electro-discharge-machined components, generates a sliding velocity and force of 100 mm/s and 12 mN, respectively, in either direction, and a peak velocity and force of 212 mm/s and 44 mN, respectively. Using a simple combination of two slightly different beams placed in contact with a slider, and vibrated at two different resonance frequencies, 508 and 522 kHz, by a specially designed, axially vibrating piezoelectric element, bidirectional linear motion was obtained. By simply reducing the length of the applied signal, the sliding distance was reduced to 90 nm +/- 2 nm, which could be improved with a variety of control methods. The design offers not only silent operation, slider clamping upon removal of power, and all of the other advantages of piezoelectric actuators, but also the potential to be further reduced in size to sub-mm3 for microrobotics and other applications.     

Numerical analysis of the symmetric hybrid transducer ultrasonicmotor

In this paper, operation of a symmetric hybrid transducer ultrasonic motor with output produced by two rotors connected together via a drive shaft is numerically analyzed and compared with the traditional asymmetric hybrid transducer motor design that produces its output from only one rotor. A one-dimensional finite element model for torsional vibration in the stator and a Coulomb friction model for rotor/stator contact associated with the longitudinal vibration of the motor are introduced. The calculation results demonstrate that the symmetric design is capable of performance comparable with the traditional asymmetric design when an optimum static spring force in the rotor/stator contact interface is applied during operation     

Finite element method failure analysis of a pressurized FRP cylinder under transverse impact loading

Safety is vital in transport vehicles, especially in case of accidents. The fuel tank must particularly be free from failure. This study discusses impact analyses of pressurized fibre-reinforced plastic (FRP) cylinders by simulation, using the finite element method. The FRP material is defined as orthotropic, and different failure conditions are defined for every failure mode. After failure, the elastic moduli are reduced, based on the appropriate damage mechanics. To represent a fluid-filled vessel, inner pressure is added to the cylinder, and nodal forces are loaded on the inner surface and side section nodes. A bar impactor hits the centre of the cylinder, vertical to the axis. As a result, the relationship between burst mode and inner pressure can be clarified.     

Ultrasonic stepping motor using spatially shifted standingvibrations

This paper proposes a novel configuration of ultrasonic stepping motor. It is based on the simple phenomena that an object on a vibrating body moves to the nodal position of the vibration mode and rests there. The use of standing flexural vibrations of a ring simplifies both the structure of the motor itself and the driving circuit. To move the nodal point, several standing modes spatially shifted with respect to each other are excited one after another by switching the driving position on the stator ring at the timing of stepping clock. In this paper, a 60-step stepping motor is designed and fabricated for trial, where an optimum combination of the order of the mode used and the number of the spatial phase shifts is discussed. The basic characteristics of the prototype motor is also studied experimentally     

A photodiode amplifier system for pulse-by-pulse intensity measurement of an x-ray free electron laser

We have developed a single-shot intensity-measurement system using a silicon positive-intrinsic-negative (PIN) photodiode for x-ray pulses from an x-ray free electron laser. A wide dynamic range (10(3)-10(11) photons/pulse) and long distance signal transmission (>100 m) were required for this measurement system. For this purpose, we developed charge-sensitive and shaping amplifiers, which can process charge pulses with a wide dynamic range and variable durations (ns-μs) and charge levels (pC-μC). Output signals from the amplifiers were transmitted to a data acquisition system through a long cable in the form of a differential signal. The x-ray pulse intensities were calculated from the peak values of the signals by a waveform fitting procedure. This system can measure 10(3)-10(9) photons/pulse of ~10 keV x-rays by direct irradiation of a silicon PIN photodiode, and from 10(7)-10(11) photons/pulse by detecting the x-rays scattered by a diamond film using the silicon PIN photodiode. This system gives a relative accuracy of ~10(-3) with a proper gain setting of the amplifiers for each measurement. Using this system, we succeeded in detecting weak light at the developmental phase of the light source, as well as intense light during lasing of the x-ray free electron laser.