Micro-Engineered Devices for Motion Energy Harvesting

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Multilayered Waveguides for Increasing the Gain Bandwidth of Integrated Amplifiers

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A comparative review of artificial muscles for microsystem applications

Artificial muscles are capable of generating actuation in microsystems with outstanding compliance. Recent years have witnessed a growing academic interest in artificial muscles and their application in many areas, such as soft robotics and biomedical devices. This paper aims to provide a comparative review of recent advances in artificial muscle based on various operating mechanisms. The advantages and limitations of each operating mechanism are analyzed and compared. According to the unique application requirements and electrical and mechanical properties of the muscle types, we suggest suitable artificial muscle mechanisms for specific microsystem applications. Finally, we discuss potential strategies for energy delivery, conversion, and storage to promote the energy autonomy of microrobotic systems at a system level

Evaluating Success in Public Health Advocacy Strategies

Advocacy is conducted by public health organisations with the aim to bring about policy improvement for better health outcomes. Implementation of a new policy usually requires a change in government practice, often to be managed by relatively conservative, and resistant, government agencies. To better understand the change process, relevant frameworks for managing transition can be used, such as Kotter's The 8-step Process for Leading Change, as suggested by David Butt. This paper assesses the extent to which this framework can assist health advocates to determine the best approach and to evaluate the effectiveness of what they are doing as advocates. We evaluate the Public Health Association of Australia's (PHAA) advocacy campaign to incorporate environmental and equity considerations into the Australian Dietary Guidelines and the Australian Guide to Healthy Eating using Kotter's framework. The PHAA's advocacy actions clearly aligned with Kotter's 8 Steps management change process. Two additional steps were also identified - the need to build long-term relationships and the importance of opportunistic actions. Management frameworks can assist health advocates to determine the key elements of effective advocacy, to plan structured advocacy campaigns and to evaluate their effectiveness. Although the policy case example is an Australian one, the principles of effective advocacy are applicable internationally

Piezoelectric wind velocity sensor based on the variation of galloping frequency with drag force

In this paper, we demonstrate a miniature energy harvesting wind velocity sensor of simple, low-cost construction, based on a single-degree-of-freedom galloping structure. The sensor consists of a prismatic bluff body with a triangular cross section attached to the free end of acantilever incorporating a commercial polyvinylidene fluoride piezoelectric film. In the wind, the bluff body causes vibration of the cantileverbased on galloping, and the piezoelectric film converts the vibration energy into an electrical signal. We have observed a negative correlationbetween the wind velocity and the vibration frequency, and we demonstrate that this relationship can be used to detect wind velocity directlywith useful accuracy. A simple theoretical model indicates that the frequency shift can be accounted for by the effect of the axial loading dueto form drag. The model shows close agreement with the experimental results. In wind tunnel tests, a prototype wind velocity sensor basedon this principle could measure wind velocities from 4.45 to 10 m/s, with the measured velocity typically being within 4% of the referencevalue obtained using a Pitot tube

A dynamic regulating mechanism for increased airflow speed range in micro piezoelectric turbines

© 2016 IEEE.The paper reports the design and fabrication of a micro-planar spring for a dynamic regulating mechanism to decrease the cut-in (start-up) airflow speed of a piezoelectric turbine. This mechanism is implemented by adjusting the magnetic coupling between the turbine rotor and a piezoelectric cantilever using the spring. Varied spring shapes and dimensions were analyzed with the finite element method (FEM) to optimize the structure. A micro spring with an ultra-low spring constant of 0.78 N/m was fabricated from titanium foil by laser machining. The spring was installed into a miniaturized air turbine to achieve the self-regulation. The cut-in speed was 2.34 m/s, showing a 30% improvement against a non-regulated turbine

Acoustic power delivery to pipeline monitoring wireless sensors

The use of energy harvesting for powering wireless sensors is made more challenging in most applications by the requirement for customi zation to each specific application environment because of specificities of the availab le energy form, such as precise location, direction and motion frequency, as well a s the temporal variation and unpredictability of the energy source. Wireless pow er transfer from dedicated sources can overcome these difficulties, and in this work, the use of targeted ultrasonic power transfer as a possible method for remote powering o f sensor nodes is investigated. A powering system for pipeline monitoring sensors is described and studied experimentally, with a pair of identical, non6inert ial piezoelectric transducers used at the transmitter and receiver. Power transmission of 18 mW (Root6Mean6Square) through 1 m of a 118 mm diameter cast iron pipe, wi th 8 mm wall thickness is demonstrated. By analysis of the delay between tran smission and reception, including reflections from the pipeline edges, a transmission speed of 1000 m/s is observed, corresponding to the phase velocity of the L(0,1) a xial and F(1,1) radial modes of the pipe structure. A reduction of power delivery with water6filling is observed, yet over 4 mW of delivered power through a fully6filled pipe i s demonstrated. The transmitted power and voltage levels exceed the requirements fo r efficient power management, including rectification at cold6starting conditions , and for the operation of low6power sensor nodes. The proposed powering technique may a llow the implementation of energy autonomous wireless sensor systems for monit oring industrial and network pipeline infrastructure

Obesity framing for health policy development in Australia, France and Switzerland

The obesity epidemic is a consequence of the interaction of cultural, environmental, genetic and behavioural factors; framing the issue is central to determining appropriate solutions. This study used content and thematic framing analysis to explore portrayal of responsibility for obesity in policy documents in Australia, France and Switzerland. For Australia and France, obesity causality was a combination of individual and environmental factors, but for Switzerland, it was predominantly individual. The primary solutions for all countries were health promotion strategies and children\u27s education. Industry groups proposed more school education while health advocates advised government intervention. Where France emphasized cultural attitudes towards taste, Australia focused on sport. The French were most keen on legislating against unhealthy foods compared with Switzerland where there was opposition towards regulation of individual\u27s choices. To curb the increasing prevalence of obesity, allocation of responsibility needs to be considered and initiatives enacted accordingly

Micro motion amplification – A Review

Many motion-active materials have recently emerged, with new methods of integration into actuator components and systems-on-chip. Along with established microprocessors, interconnectivity capabilities and emerging powering methods, they offer a unique opportunity for the development of interactive millimeter and micrometer scale systems with combined sensing and actuating capabilities. The amplification of nanoscale material motion to a functional range is a key requirement for motion interaction and practical applications, including medical micro-robotics, micro-vehicles and micro-motion energy harvesting. Motion amplification concepts include various types of leverage, flextensional mechanisms, unimorphs, micro-walking /micro-motor systems, and structural resonance. A review of the research state-of-art and product availability shows that the available mechanisms offer a motion gain in the range of 10. The limiting factor is the aspect ratio of the moving structure that is achievable in the microscale. Flexures offer high gains because they allow the application of input displacement in the close vicinity of an effective pivotal point. They also involve simple and monolithic fabrication methods allowing combination of multiple amplification stages. Currently, commercially available motion amplifiers can provide strokes as high as 2% of their size. The combination of high-force piezoelectric stacks or unimorph beams with compliant structure optimization methods is expected to make available a new class of high-performance motion translators for microsystems

Continuously Rotating Energy Harvester with Improved Power Density

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