1D Nanostructure-Based Piezo-Generators

International audienceWith the amount of connected objects constantly on the rise, both in our daily life and in high-technology applications, it becomes critical to deal with their associated increase in energy consumption. Their energetic autonomy is currently a key worldwide challenge with strong economic and environmental benefits. The recent miniaturization of electronic micro-devices have resulted in the reduction of energy consumption to mW and even µW, combined with the progress in micro-nano-fabrication, and have opened, in these last years, new perspectives to develop autonomous power systems based on the renewable energy harvesting

Vibrating a small plate vortex generator to improve control robustness of a micro aerial delta wing vehicle

In the work, vortex generators as a small vibrating plates adjusted to a delta wing surface are used for boundary layer control (BLC). The vortex generators applied to produce aircraft moments and aerodynamic forces are proposed and tested. The BLC for delta wing micro aircraft is calculated numerically by using fluid-structure interactions. The Navier-Stokes equations and Shear Stress Transport (SST) model were used for numerical calculations. The flexible oscillating small plates driven by controlled piezo stacks and their influence on the air flow in the delta boundary layer are investigated. The amplitude of the piezo stack vortex generator and frequency measurements are presented

ENERGY SAVING. PIEZOGENERATORS

The object of consideration is a static generator of piezoelectric energy. The purpose of the work is to study the operation modes and designs of piezoelectric converters; selection of a suitable design for the converter; the development of the model of the converter and the determination of its output characteristics. The work is devoted to the development, research and creation of piezoelectric generator of static type. This generator can be a small independent power source of autonomous different devices of radio electronics, as it transforms the free energy of vibrations of the external environment into an electrical signal. In addition, solving problems related to strength characteristics will allow us to use this type of piezo-generators in the future under conditions of a nonlinear stress-strain state

Piezoelectric wind power harnessing – an overview

As fossil energy resources deplete, wind energy gains ever more importance. Recently, piezoelectric energy harvesting methods are emerging with the advancements in piezoelectric materials and its storage elements. Piezoelectric materials can be utilized to convert kinetic energy to electrical energy. Utilization of piezoelectric wind harvesting is a rather new means to convert renewable wind energy to electricity. Piezoelectric generators are typically low cost and easy to maintain. This work illustrates an overview of piezoelectric wind harvesting technology. In wind harvesting, piezoelectric material choice is of the first order of importance. Due to their strain rate, robustness is a concern. For optimum energy harvesting efficiency resonant frequency of the selected materials and overall system configuration plays important role. In this work, existing piezoelectric wind generators are grouped and presented in following categories: leaf type, rotary type, rotary to linear type and beam type wind generators

Vibrating a small plate vortex generator to improve control robustness of a micro aerial delta wing vehicle

In the work, vortex generators as a small vibrating plates adjusted to a delta wing surface are used for boundary layer control (BLC). The vortex generators applied to produce aircraft moments and aerodynamic forces are proposed and tested. The BLC for delta wing micro aircraft is calculated numerically by using fluid-structure interactions. The Navier-Stokes equations and Shear Stress Transport (SST) model were used for numerical calculations. The flexible oscillating small plates driven by controlled piezo stacks and their influence on the air flow in the delta boundary layer are investigated. The amplitude of the piezo stack vortex generator and frequency measurements are presented

Vibrating a small plate vortex generator to improve control robustness of a micro aerial delta wing vehicle

In the work, vortex generators as a small vibrating plates adjusted to a delta wing surface are used for boundary layer control (BLC). The vortex generators applied to produce aircraft moments and aerodynamic forces are proposed and tested. The BLC for delta wing micro aircraft is calculated numerically by using fluid-structure interactions. The Navier-Stokes equations and Shear Stress Transport (SST) model were used for numerical calculations. The flexible oscillating small plates driven by controlled piezo stacks and their influence on the air flow in the delta boundary layer are investigated. The amplitude of the piezo stack vortex generator and frequency measurements are presented

Footstep Power Generation using Piezo Ceramic

People move all the time. Wouldn’t it be great to harness that movement and help to power our cities with the movement of people living in them? Piezoelectric harvesting is one of the most reliable and energy efficient method. The crystalline structure of piezoelectric material provides the ability to transform mechanical strain energy into electrical energy. The power generated by piezo is D.C signal with A.C ripples, which is not used directly for battery charging so hence we use rectifier and filter to get pure D.C signal. Further boost converter circuit is used to step up the D.C signal and through battery charger circuit, battery is charged. This charge can be used to drive the a.c loads by converting D.C signal to A.C with help of inverter circuit

PROTOTYPING efnMOBILE

This edition of Imagine is about a mobile workshop concept, which is and has been travelling across Europe. It links several universities that are members of the European Facade Network, which is developing a closeknit cadre of facade designers and specialists. What is interesting is to see how this workshop is fostering this network by serving as a platform to test concepts through the realisation of 1:1 mockups. Of course, none of the concepts are perfect or even properly functional, but it is the experience and the knowledge gained that are the real products – and once in a while good ideas do come out of it and voila: facade innovation is literally at hand

Effect of Calcination Temperature on Microstructural Evolution of Electrospun ZnO Fibers

Development of portable or wearable devices demands for flexible, lightweight or even foldable materials for fabrication. In this respect, electrospinning offers a cost-effective, high throughput, versatile and scalable route for the production of flexible micro/nanofibers on almost all kinds of surfaces. In this work, semiconducting ZnO fibers of high aspect ratios were electrospun from organic precursor of ZnO solution. The effect of calcination temperature on the microstructures of the electrospun fibers was investigated. Simultaneous thermal analysis (STA) was used to monitor the temperature at which the organic precursor was removed to form ZnO. X-ray diffraction (XRD), on the other hand, was used to monitor the phase formations at various heating stages. Field emission scanning electron microscope (FESEM) equipped with energy dispersive spectrometry (EDX) was employed for morphological study of the ZnO produced. Continuous single phase ZnO fibers started to form at a temperature of around 460 °C and evolved through various stages of microstructural formations, from tubular-like structures to segmentation of granular structures and hierarchical structures at further increases in calcination temperatures. The ZnO fibers experienced increasing crystallinity and stoichiometry change during the heating process. When mechanically bent, the fibers were able to generate current pulses of between 0.1 to 10 nA

Design of a Monosized Droplet Generator

This dissertation focuses on the development and validation of an instrument that allows the formation of drops. This document starts by showing the design developed for this purpose. After the development of the design, the pieces were built using 3D printing. When the process was complete, the device was assembled and validated. For the validation of this instrument, it was necessary to create a test station which is shown in chapter 3. After the entire assembly process, the validation tests were carried out. In the validation phase, water was applied to be ejected by the apparatus. Six different flow rates were implemented in order to determine the effect of the flow rate on the formation and behavior of the drops. The results of these tests were obtained through visualization methods. After all the images were collected in the testing phase, they were analyzed for the extraction of diameters. After the tests of undisturbed droplet formation were completed, the disturbed generation of droplets was proceeded to test. In this testing phase, three flows were chosen from the previous phase and imposed. The flow rates chosen for the disturbed phase of the generation of droplets were: 2.5, 4 and 5 ml/min. The proceedings for these tests was the flow and signal implementation. After the flow was implemented, the electromagnetic wave was built to be implemented in the piezoelectric cell. The electromagnetic signal consists of a square wave of constant amplitude (20 Vpp), where the frequency is periodically increased. The study with several frequencies aims to investigate the influence of frequency on the forma- tion of drops for the case of this instrument. This study allows testing whether the apparatus is capable of creating consecutive drops with high repeatability in terms of diameter and spacing between drops. Like the undisturbed cases, the disturbed droplet formation was also tested through visualization and image analysis.Esta dissertação foca-se no desenvolvimento e validação de um instrumento que permite a for- mação de gotas. Este documento começa por mostrar o design desenvolvido para este propósito. Após o desenvolvimento do design, as peças foram construídas recorrendo à impressão 3D. Após a impressão das peças, procedeu-se à montagem e validação do dispositivo. Para a validação deste instrumento, foi necessário criar uma estação de testes que é mostrada no capítulo 3. Após todo o processo de montagem, realizaram-se os testes de validação. Na fase de validação, usou-se água para a validação do aparelho. Seis caudais diferentes foram implementados, de forma a determinar o efeito do caudal na formação e comportamento das gotas. Os resultados destes testes foram obtidos através de métodos de visualização. Após todas as imagens serem recolhidas na fase de testes, estas foram analisadas para a extracção de diâmetros. Depois deste processo ter sido concluido, procedeu-se a testar a geração de gotas perturbada. Nesta fase de testes, três caudais foram escolhidos de entre os im,postos na primeira fase de validação e impostos. Os caudais escolhidos para a fase perturbada da geração de gotas foram: 2.5, 4 e 5 ml/min. O procedimento para estes testes foi a implementação do caudal e do sinal. Após a implementação do caudal, a onda electromagnética foi construída para implementar na célula piezoeléctrica. O sinal electromagnético consiste numa onda quadrada de amplitude constante (20 Vpp), onde a frequência é periodicamente aumentada. O estudo com várias frequências visa a investigação da influência da frequência na formação de gotas para o caso deste instrumento. Este estudo permite testar se o aparato é capaz de criar gotas consecutivas com alta repetibilidade no que toca a diâmetros e espaçamento entre gotas. À semelhança dos casos não perturbados, a formação perturbada de gotas também foi testada através de visualização e análise de imagem