750 research outputs found
An improved thick-film piezoelectric material by powder blending and enhanced processing parameters
No full textThis paper details improvements of the d33 coefficient for thick-film lead zirconate titanate (PZT) layers. In particular, the effect of blending ball and attritor milled powders has been investigated. Mathematical modeling of the film structure has produced initial experimental values for powder combination percentages. A range of paste formulations between 8:1 and 2:1 ball to attritor milled PZT powders by weight have been mixed into a screen-printable paste. Each paste contains 10% by weight of lead borosilicate glass and an appropriate quantity of solvent to formulate a screen printable thixotropic paste. A d33 of 63.5 pC/N was obtained with a combination of 4:1 ball milled to attritor milled powder by weight. The improved paste combines the high d33 values of ball and the consistency of attritor milled powder. The measured d33 coefficient was further improved to 131 pC/N by increasing the furnace firing pro-file to 100
Performance of a micro-engineered ultrasonic particle manipulator
No full textAn ultrasonic microfluidic particle manipulator has been modeled and its experimentally measured separation performance has been compared with the modeled results for 1 µm latex particles, and yeast particles in water
Self-powered autonomous wireless sensor node using vibration energy harvesting
No full textThis paper reports the development and implementation of an energy aware autonomous wireless condition monitoring sensor system (ACMS) powered by ambient vibrations. An electromagnetic (EM) generator has been designed to harvest sufficient energy to power a radio-frequency (RF) linked accelerometer-based sensor system. The ACMS is energy aware and will adjust the measurement/transmit duty cycle according to the available energy; this is typically every 3 s at 0.6 m s?2 rms acceleration and can be as low as 0.2 m s?2 rms with a duty cycle around 12 min. The EM generator has a volume of only 150 mm3 producing an average power of 58 ?W at 0.6m s?2 rms acceleration at a frequency of 52 Hz. In addition, a voltage multiplier circuit is shown to increase the electrical damping compared to a purely resistive load; this allows for an average power of 120 ?W to be generated at 1.7 m s?2 rms acceleration. The ACMS has been successfully demonstrated on an industrial air compressor and an office air conditioning unit, continuously monitoring vibration levels and thereby simulating a typical condition monitoring applicatio
Experimental investigation into the effect of substrate clamping on the piezoelectric behaviour of thick-film PZT elements
No full textThis paper details an experimental investigation of the clamping effect associated with thick-film piezoelectric elements printed on a substrate. The clamping effect reduces the measured piezoelectric coefficient, d33, of the film. This reduction is due to the influence of the d31 component in the film when a deformation of the structure occurs, by either the direct or indirect piezoelectric effect. Theoretical analysis shows a reduction in the measured d33 of 62%, i.e. a standard bulk lead zirconate titanate (PZT)-5H sample with a manufacturer specified d33 of 593pC/N would fall to 227.8pC/N. To confirm this effect, the d33 coefficients of five thin bulk PZT-5H samples of 220µm thickness were measured before and after their attachment to a metallized 96% alumina substrate. The experimental results show a reduction in d33 of 74% from 529pC/N to 139pC/N. The theoretical analysis was then applied to existing University of Southampton thick-film devices. It is estimated that the measured d33 value of 131pC/N of the thick-film devices is the equivalent of an unconstrained d33 of 345pC/N
A silicon microfluidic ultrasonic separator
No full textUltrasonic standing waves can be used to generate forces on particles within a fluid. Such forces have a number of potential applications in microfluidic devices. This paper describes such a device providing filtration on a microfluidic scale. It is microfabricated and uses ultrasound in the megahertz frequency range to concentrate particles at a node within the flow. It offers the possibility of a functional equivalent of a centrifugal separator for microfluidic systems. It is constructed using silicon and Pyrex, and hence is highly compatible with established microfabrication techniques. The modelling, design, fabrication and control of the device are discussed
Dataset for Solid-State Supercapacitor Fabricated in a Single Woven Textile Layer for E-Textiles Applications
No full textThe data is supporting a paper S Yong. J R Owen. S. Beeby, "Solid-State Supercapacitor Fabricated in a Single Woven Textile Layer for E-Textiles Applications ", Advanced Engineering Materials. 2017
Assigned DOI is https://doi.org/10.5258/SOTON/D0321</span
Optimization of an Electromagnetic Energy Harvesting Device
No full textThis paper presents the modeling and optimization of an electromagnetic-based generator for generating power from ambient vibrations. Basic equations describing such generators are presented and the conditions for maximum power generation are described. Two-centimeter scale prototype generators, which consist of magnets suspended on a beam vibrating relative to a coil, have been built and tested. The measured power and modeled results are compared. It is shown that the experimental results confirm the optimization theory
Dataset for Efficient Energy Conversion in Electrically Assisted Bicycles Using a Switched Reluctance Machine under Torque Control
No full textThis dataset supports the publication: Bahareh Zaghari, Aleksas Stuikys, Alex S. Weddell, Steve Beeby Efficient Energy Conversion in Electrically Assisted Bicycles Using a Switched Reluctance Machine under Torque Control IEEE ACCESS</span
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