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1 – 10 of 167S.P. Beeby, N.J. Grabham and N.M. White
This paper describes a self‐test procedure for a micromachined silicon accelerometer realized using a commercially available microprocessor. The accelerometer is fabricated using…
Abstract
This paper describes a self‐test procedure for a micromachined silicon accelerometer realized using a commercially available microprocessor. The accelerometer is fabricated using a combination of thick‐film printing and silicon micromachining. It consists of a silicon structure with thick‐film piezoelectric elements that act as sensors, detecting the deflections of the inertial mass, and also as actuators capable of performing a self‐test routine. The self‐test procedure must be performed at resonance and the microprocessor is used to identify the individual resonant frequency of each device and confirm the operation of the PZT elements. This work has successfully demonstrated the feasibility of a microprocessor implemented procedure and has highlighted some interesting behavioral characteristics of the accelerometer. The microprocessor could also be used in the future to fully test and calibrate the device thereby ensuring correct and accurate operation.
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Thomas H. Owen, Stefan Kestermann, Russel Torah and Stephen P. Beeby
The purpose of this paper is to demonstrate the feasibility of using kinetic energy harvesting to power wireless condition monitoring sensors.
Abstract
Purpose
The purpose of this paper is to demonstrate the feasibility of using kinetic energy harvesting to power wireless condition monitoring sensors.
Design/methodology/approach
The system presented duty cycles its operation depending upon the energy being harvested. The harvested energy is stored on a supercapacitor and the system samples sufficient vibration data to enable an FFT to be performed at the receiver.
Findings
The results of this study show it is perfectly feasible to power practical wireless condition monitoring sensors entirely from the vibrations of the machines being monitored.
Originality/value
Energy harvesting techniques can be used to power wireless sensors in a range of applications. Removing the need for a battery power supply presents obvious environmental benefits and avoids the need to periodically replace batteries.
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T. Yan, B.E. Jones, R.T. Rakowski, M.J. Tudor, S.P. Beeby and N.M. White
This paper reports on a novel load cell and a novel torque transducer having stiffness and potential overload capability some ten times that of existing load cells and torque…
Abstract
Purpose
This paper reports on a novel load cell and a novel torque transducer having stiffness and potential overload capability some ten times that of existing load cells and torque transducers based on the resistance strain gauges.
Design/methodology/approach
Describes the practical capabilities and technology – the design, construction and characterisation.
Findings
Both the load cell and the torque transducer use recently developed metallic triple beam resonators with thick‐film lead zirconate titanate (PZT) drives and pickups. The advantages of this technology are frequency output, high overload capability, high sensitivity, high resolution, and low‐cost manufacture. Both the load cell and torque transducer output large changes in frequency (>500 Hz for relatively low changes in strain level i.e. <200 microstrain for the load cell and <400 microstrain for the torque transducer), providing high sensitivity and high overload capability.
Practical implications
Load cells and torque transducers employing the new metallic resonators are expected to be far more robust than those using metallic resistance strain gauges.
Originality/value
Focuses on an instrument with important features of use in many applications.
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Takahiro Sato, Yuki Sato and Hajime Igarashi
The finite element method (FEM) for 3D models needs heavy computational cost. The computational cost for FE analysis of moving objects, e.g. Vibration energy harvester, must be…
Abstract
Purpose
The finite element method (FEM) for 3D models needs heavy computational cost. The computational cost for FE analysis of moving objects, e.g. Vibration energy harvester, must be reduced to exploit the simulation of the dynamic system in its design. The paper aims to discuss these issues.
Design/methodology/approach
To reduce the computational time of FEM, the model order reduction (MOR) based on proper orthogonal decomposition has been proposed. For the moving systems, MOR is modified.
Findings
It is shown that proposed MOR makes it possible to drastically reduce the coupling analysis of the energy harvester in which the equations of motion, magnetostatics, and circuit are repeatedly solved.
Originality/value
To reduce the computational time of FEM, block-MOR is presented, in which the whole domain is subdivided into N-blocks. As a result computational cost for MOR can be reduced.
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The paper aims to present numerical modeling and technology of a very first three axial low temperature cofired ceramics (LTCC) accelerometer.
Abstract
Purpose
The paper aims to present numerical modeling and technology of a very first three axial low temperature cofired ceramics (LTCC) accelerometer.
Design/methodology/approach
Low temperature cofired ceramics technology was applied in the fabrication process of the novel device. The numerical modeling was used to predict the properties of the accelerometer, moreover, design of the experiment methodology was used to reduce time of simulation and to get as much as information from the experiment as possible.
Findings
The low temperature cofired ceramics make it possible to fabricate three axial accelerometer.
Research limitations/implications
The presented device is just a first prototype. Therefore, further research work will be needed to improve structural drawbacks and to analyze precisely the device reliability and parameters repeatability.
Practical implications
The device presented in the paper can be applied in systems working in a harsh environment (high temperature and humidity). Ceramic sensors can withstand temperatures up to 600°C.
Originality/value
This paper presents novel three axial LTCC accelerometer.
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Cam Minh Tri Tien and Nam Seo Goo
Current technology uses large windmills that operate in remote regions and have complex generating mechanisms such as towers, blades gears, speed controls, magnets, and coils. In…
Abstract
Purpose
Current technology uses large windmills that operate in remote regions and have complex generating mechanisms such as towers, blades gears, speed controls, magnets, and coils. In a city, wind energy that would otherwise be wasted can be claimed and stored for later use. The purpose of this paper is to introduce a small‐scale windmill that can work in urban areas.
Design/methodology/approach
The device uses a piezo‐composite generating element (PCGE) to generate the electric power. The PCGE is composed of layers of carbon/epoxy, lead zirconate titanate (PZT) ceramic, and glass/epoxy cured at an elevated temperature. Previous work by the authors had proved that the PCGE can produce high performance energy harvesting.
Findings
In the prototype, the PCGE performed as a secondary beam element. One end of the PCGE is attached to the frame of the device. Additionally, the fan blade rotates in the direction of the wind and hits the other end of the PCGE. When the PCGE is excited, the effects of the beam's deformation enable it to generate electric power. The power generation and battery charging capabilities of the proposed device were tested, and the results show that the prototype can harvest energy in urban regions using minor wind movement.
Originality/value
The paper presents a prototype that uses a PCGE for harvesting wind energy in urban areas. The PCGE has the potential of being used as a generator for harvesting energy from sources such as machine vibration, body motion, wind, and ocean waves. The PCGE design is flexible: the ply orientation and the size of the prepreg layers can be changed. Generating elements with a specific stacking sequence can be used for scavenging energy in a wide range of applications such as network sensors, portable electronics, and microelectromechanical systems.
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In light of contemporary critiques of New Zealand comprehensive schooling published mainly in the popular press, it is timely to re‐examine the origins of and the rationale for…
Abstract
In light of contemporary critiques of New Zealand comprehensive schooling published mainly in the popular press, it is timely to re‐examine the origins of and the rationale for the widespread adoption of this model of education. The comprehensive schooling philosophy, it was recently alleged, has produced a situation in which ‘as many as one in five pupils in the system is failing’ and where ‘there is a large group at the bottom who are not succeeding’. This group was estimated to include some 153,000 students out of the total current New Zealand student population of 765,000. In this context, however, Chris Saunders and Mike Williams, principals of Onehunga High School and Aorere College in Auckland respectively, have noted that having underachieving students in secondary schools in particular is not a recent phenomenon. A large ‘tail’ of poor performing high school students has long been a cause of concern, Williams suggests.
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Darko Belavič, Andraž Bradeško, Tomaz Kos and Tadej Rojac
In this contribution, the design and integration of a piezoelectric vibrating device into low-temperature, co-fired ceramic (LTCC) structures are presented and discussed. The…
Abstract
Purpose
In this contribution, the design and integration of a piezoelectric vibrating device into low-temperature, co-fired ceramic (LTCC) structures are presented and discussed. The mechanical vibration of the diaphragm was stimulated with a piezoelectric actuator, which was integrated onto the diaphragm. Three different methods for the integration were designed, fabricated and evaluated.
Design/methodology/approach
The vibrating devices were designed as an edge-clamped diaphragm with an integrated piezoelectric actuator at its centre, whose role is to stimulate the vibration of the diaphragm via the converse piezoelectric effect. The design and feasibility study of the vibrating devices was supported by analytical methods and finite-element analyses.
Findings
The benchmarking of the ceramic vibrating devices showed that the thick-film piezoelectric actuator responds weakly in comparison with both the bulk actuators. On the other hand, the thick-film actuator has the lowest dissipation factor and it generates the largest displacement of the diaphragm with the lowest driving voltage. The resonance frequency of the vibrating device with the thick-film actuator is the most sensitive for an applied load (i.e. mass or pressure).
Research limitations/implications
Research activity includes the design and the fabrication of a piezoelectric vibrating device in the LTCC structure. The research work on the piezoelectric properties of integrated piezoelectric actuators was limited.
Practical implications
Piezoelectric vibrating devices were used as pressure sensors.
Originality/value
Piezoelectric vibrating devices could be used not only for pressure sensors but also for other type of sensors and detectors and for microbalances.
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P. Glynne‐Jones and N.M. White
A range of self‐power technologies is reviewed. Self‐powered systems are defined as those that operate by harnessing ambient energy present within the environment of the system…
Abstract
A range of self‐power technologies is reviewed. Self‐powered systems are defined as those that operate by harnessing ambient energy present within the environment of the system. As MEMS and smart‐material technologies mature, embedded and remote systems become more attractive. Self‐power offers a potential for solving the difficult problem of supplying energy to these devices.
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