Compact near field wireless energy transfer systems using defected ground structures

Near-Field Wireless Power Transfer systems have attracted attention for their potential applications, such as implanted medical devices, radio frequency identification, and portable electronic devices in general. In this context, a compact model for short-range NF-WPT systems operating in ISM frequency bands is proposed, employing the concept of ground plane aperture resonators or Defected Ground Structures (DGS). This technique allows the miniaturization of the resonator, which leads to the development of compact NF-WPT systems. The model proposed in this work aims at possible applications that require simultaneous energy and data transfer. This model operates in dual band in 433 MHz and 900 MHz frequency bands and makes use of overlapping circular DGS in order to shrink the resonator device and obtain high values of Figure of Merit (FoM) commonly used in this research area. The proposed model was designed using the electromagnetic analysis and built using Rogers RO4003 dielectric material. The designed dual-band DGS resonators have a total area of 11.7 × 10.2 mm 2 and when placed at a distance of 15 mm between transmitter and receiver, they have measured FoM values of 0.71 and 1.07 at 440 MHz and 918 MHz, respectively. The results were compared with related works found in the literature, and indicate a ηWPT of 40.9% and 49.2 %

Tracking and dynamic tuning of a wireless powered endoscopic capsule

This work presents an inductive wireless power transfer system for powering an endoscopy capsule supplying energy to power electronic devices allocated inside a capsule of ≈26.1 mm × 9 mm. A receiver with three coils in quadrature with dimensions of ≈9 mm × 9 mm × 10 mm is located inside the capsule, moving freely inside a transmitter coil with 380 mm diameter through translations and revolutions. The proposed system tracks the variations of the equivalent magnetic coupling coefficient compensating misalignments between the transmitter and receiver coils. The power on the load is estimated and optimized from the transmitter, and the tracking control is performed by actuating on a capacitance in the matching network and on the voltage source frequency. The proposed system can prevent load overheating by limiting the power via adjusting of the magnitude of voltage source VS. Experimental results with uncertainties analysis reveal that, even at low magnetic coupling coefficients k ranging from (1.7 × 10−3 , 3.5 × 10−3 ), the power on the load can be held within the range of 100–130 mW. These results are achieved with any position of the capsule in the space, limited by the diameter of the transmitter coil and height of 200 mm when adjusting the series capacitance of the transmitter in the range (17.4, 19.4) pF and the frequency of the power source in the range (802.1, 809.5) kHz

Development of a pavement-embedded piezoelectric harvester in a real traffic environment

Road pavements are spread over large areas and convey various possibilities for energy sources such as high thermal gradients due to their materials and colors, wind corridors, large flat areas for solar harvesting, and heavy loading from traffic. The latest advances in road energy generation have been discretely implemented and have mainly focused on photovoltaic surface applications; other studies have explored the use of piezoelectric transducers with high stresses for better energy-production performance but limited life span. This study explores the stresses on pavement surfaces from traffic loading shockwaves that yield to the natural frequency vibration a piezoelectric harvester using a cantilever array. The passing vehicles triggered 16 piezoelectric sensors divided into four embedded steel profiles. The peak electrical power obtained in the experiment was 55.6 µW with a single transducer using a tip mass of 16 g. The proposed harvester demonstrated potential for applications in micro-generation of energy with limited infrastructure modification and high endurance under traffic loading over time. Its generation capacity is around 50 mWh a month with 16 piezoelectric cantilevers installed (for a commercial traffic volume of 1500 vehicles a day), enough to power a 200 m flashing LED raised marker strip to guide drivers for lane alignment during night shifts

Displacer-type liquid level sensor with liquid density auto-compensation

In the classic displacer-type liquid level measuring method, liquid level is calculated via the buoyancy force exerted by the liquid on a displacer. This technology has high linearity, precision, accuracy, ease of installation and low cost. Nonetheless, displacer level sensors have significant sensitivity to variations in liquid density, which hinder its use in industrial applications that such quantity is not held constant. In this paper a novel displacer-type liquid level sensor is presented and analyzed. The innovation of the new sensor consists of adding another displacer and thus calculating the new measured value by the quotient of the buoyancy forces of both displacers. Therefore, the new measurement is ideally insensitive to the variations in liquid density. A prototype was built and prototype results presented high linearity, being able to mitigate the sensitivity to the liquid density, increasing accuracy in the measurements

Utilização de sensores magnéticos para medição de deslocamento sem contato

O objetivo deste trabalho é desenvolver e avaliar um sistema capaz de reproduzir na tela de um microcomputador o movimento de um ponto, sem qualquer contato no mesmo. Para construir o protótipo foram utilizados sensores magnetoresistivos, um superímã, e para calibração, uma mesa adaptada com três parafusos micrométricos, capaz de realizar um deslocamento nas coordenadas x, y e z de um sistema tridimensional. Este estudo foi dividido em duas partes, na primeira avaliou-se o comportamento do sistema para a variação de deslocamento em um plano, caracterizando um movimento em duas dimensões (20). Na segunda parte, foi inserido um terceiro eixo, reproduzindo assim deslocamentos em 3 dimensões (30). O sistema apresentou resultados coerentes e comprovou ser uma opção para medidas desta natureza. Considerando-se os limites de precisão e tolerância necessárias, aplicações nas áreas de controle e Engenharia Biomédica podem ser implementadas baseadas no estudo de medidas sem contato.The aim of this work is to develop and evaluate a system to reproduce the movement of a point on a microcomputer screen in real time and contactless between the point and the sensor. To build the prototype, were used magnetoresistives sensors, a magnet and a calibration table adapted with three micrometric screws to accomplish the displacement on x, y and z coordenates of a 30 system. This study has been divided into two parts. In the first, the bahaviour of the system was asseded for the displacement variation of a point on a plane (20). In the second part, a third axis was inserted, thus reproducing 30 displacements. The system has present consistent resuslts and prove to be an alternative for mesurements of this nature. Considering necessary accuracy and tolerance limits, aplications in Control and Biomedical Engeneering can be implemented, based on the study of contactless mesurement

Sosiaalisen kuntoutuksen kehittämisen lähtökohdat Kauniaisissa

Opinnäytetyön tarkoituksena oli tuottaa tietoa sosiaalisen kuntoutuksen palveluiden kehittämiseksi Kauniaisten sosiaali- ja terveystoimeen. Sosiaalihuoltolain uudistuksen myötä sosiaalinen kuntoutus tuli lakisääteiseksi palveluksi, minkä vuoksi se on aiheena ajankohtainen. Opinnäytetyön avulla oli tarkoitus luoda lähestymistapa, jossa sosiaalisen kuntoutuksen palvelut saataisiin entistä paremmin toimiviksi. Tavoitteena oli selvittää, millä edellytyksillä voidaan saavuttaa vaikuttavia ja asiakaslähtöisiä sosiaalisen kuntoutuksen palveluita. Tutkimuskysymykset olivat: Mitä on sosiaalinen kuntoutus ja mitä se on Kauniaisissa? Millaisille sosiaalisen kuntoutuksen palveluille on tarvetta Kauniaisissa? Opinnäytetyössä on piirteitä arviointitutkimuksesta ja toimintatutkimuksesta. Tutkimusaineisto kerättiin aikuissosiaalityön asiakkaiden teemahaastatteluilla ja Kauniaisten sosiaalialan henkilöstön työpajan avulla. Opinnäytetyötä varten haastateltiin kuutta pitkäaikaistyötöntä aikuissosiaalityön asiakasta. Teemahaastatteluilla selvitettiin asiakkaiden näkemyksiä heidän toiminta- ja työkyvystään sekä sosiaalisen kuntoutuksen palveluista. Sosiaalialan henkilöstön työpaja sosiaalisen kuntoutuksen palveluihin liittyen toteutettiin seitsemän sosiaalialan ammattilaisen kesken ja siihen osallistuneet henkilöt olivat sosiaalityöntekijöitä sekä sosiaali- ja palveluohjaajia. Opinnäytetyössä tarkasteltiin lisäksi aikaisempien tutkimusten valossa, kuinka sosiaalista kuntoutusta on toteutettu, millaisille palveluille on ollut tarvetta sekä millaisia sosiaalisen kuntoutuksen tuloksia on saatu. Aikaisempien tutkimusten perusteella sosiaalisen kuntoutuksen palveluiden tulisi olla voimaannuttavia, mielekkäitä ja yksilöllisiä asiakkaille. Sosiaalisen kuntoutuksen palveluiden tulisi tähdätä asiakkaiden elämänhallinnan ja työllistymisedellytysten parantamiseen sekä toimintakyvyn vahvistamiseen. Toiminta voi olla ryhmämuotoista tai yksilötoimintaa. Palveluiden organisointiin tulisi varata tarpeeksi ja kyllin monialaista henkilöstöä. Tutkimustulosten mukaan sosiaalisen kuntoutuksen piiriin kuuluvia palveluita on järjestetty Kauniaisissa tapauskohtaisesti räätälöiden, ilman vakiintunutta toimintamallia. Toimintaa on toteutettu asiakaslähtöisesti ja sosiaalityön palveluita on jalkautettu asiakkaiden ympäristöihin siinä määrin, mitä on ollut mahdollista. Tutkimustulosten perusteella toimijoiden työnkuvat ja vastuut tulisi määritellä selkeästi. Asiakkaat kaipaavat enemmän tiedotusta liittyen pitkäaikaistyöttömien palveluihin ja sosiaaliseen kuntoutukseen. Vaikuttavaa sosiaalista kuntoutusta ovat palvelut, joissa kiinnitetään huomiota yksilöllisyyteen ja räätälöidään palvelut asiakkaiden tarpeiden mukaan ja asiakkaiden toimintakykyä tukeviksi ja edistäviksi. Asiakaslähtöisyys tulisi näkyä palveluissa niin, että palveluketju on asiakkaalle selkeä. Esimerkkinä mahdollisista kehittämistoimenpiteistä Kauniainen on esittämässä selvityshenkilön palkkaamista aktivointityöhön kauniaislaisille pitkäaikaistyöttömille, joista osa saattaa siis olla myös sosiaalisen kuntoutuksen tarpeessa.The purpose of this thesis was to produce information to Kauniainen Social Welfare and Health Office to develop social rehabilitation services. As the Social Welfare Act was renewed, social rehabilitation became a statutory service, and therefore it is a topical issue. By means of this thesis, the purpose was to create an approach where social rehabilitation services would be better operational than they were before. The aim was to find out, how to achieve effective and customer-oriented social rehabilitation services. The research questions were: What is social rehabilitation and what is it in Kauniainen? What kind of social rehabilitation services are needed in Kauniainen? The thesis has the features of evaluation research and action research. The data was gathered through adult social customer interviews and a workshop with the staff of Kauniainen Social Services. Six long-term unemployed customers, who were customers of adult social work, were interviewed for this thesis. Theme interviews were used to find out customers' perceptions of their functional and working capacity as well as social rehabilitation services. The social staff workshop according to social rehabilitation services was conducted among seven social welfare professionals and the people participated in it were social workers as well as social and service counselors. In addition, in the light of previous studies on how social rehabilitation has been carried out, the study examined what kind of services has been needed, and what results have been obtained in social rehabilitation. On the basis of previous studies, social rehabilitation services should be empowering, meaningful and individual to the customers. Social rehabilitation services should aim to improve the customers' life management and employment potential as well as the strengthening of the capacity. Actions can be activities in groups or individual activities. Enough multi-disciplinary staff should be reserved. According to research results, social rehabilitation services have been organized in Kauniainen by tailoring on a case by case basis, without an established approach. Services have been carried out in a customer-oriented way and services have been exported within customer environments to the extent of what has been possible. On the basis of research results, work descriptions and responsibilities of the actors should be clearly defined. Customers wish more information concerning services for long-term unemployed and social rehabilitation. Effective social rehabilitation is the service where attention is paid to individuality and the services are tailored to customers' needs and to promote customers' functional ability. Customer orientation should be reflected in services in such a way that the service chain would be clear from the customers' point of view. As an example of possible development measures, Kauniainen is proposing of hiring a person who activates the Kauniainen long-term unemployed persons. Some of them may therefore also be in need of social rehabilitation

Investigation of the main corrosion processes on electrical energy stations of the state of Rio Grande do Sul - Brasil

Este estudo investigou os principais agentes de corrosão em quatro subestações de energia elétrica do estado do Rio Grande do Sul, três no litoral e uma em Porto Alegre. O objetivo foi determinar as taxas de corrosão de vários materiais metálicos expostos aos agentes agressivos existentes no ambiente das subestações. Foram desenvolvidos experimentos de perda de massa dos materiais expostos em tempo real nas subestações, monitoramento de potencial do solo, determinação da composição química e resistividade do solo, e análise micrográfica e química dos materiais após exposição no sítio de trabalho. Os ensaios de perda de massa foram realizados seguindo as normas ISO (International Organization of Standardization) 8407, 8565 e 9223 a 9227. A resistividade do solo foi determinada pelo método Wenner e as micrografias e constituição química dos produtos de corrosão por microscopia eletrônica de varredura e espectroscopia de energia dispersiva, respectivamente Resultados mostraram significativa alteração nas massas do aço e do cobre, principalmente nas subestações litorâneas. Embora os agentes corrosivos existam no solo, as altas taxas de corrosão no litoral estão fortemente associadas à maresia. Já para o zinco e o aço galvanizado, a corrosão foi mais expressiva em Porto Alegre, região urbana sem presença de maresia. Os solos de todas as subestações estudadas apresentaram alta resistividade, o que implica em baixa agressividade destes aos materiais metálicos. Com estas conclusões, fica evidente que os procedimentos e precauções em relação à corrosão dos componentes metálicos das subestações expostas a condições extremas de agressividade, como em presença de íons cloreto e particulados sólidos, não podem ser os mesmos que os adotados para os ambientes livres destes componentes.This study investigated the main corrosion agents in four electric energy station in the state of Rio Grande do Sul, three on the coast and one in Porto Alegre (capital of Rio Grande do Sul). The objective was to determine the corrosion rates of various metallic materials exposed to the aggressive agents present in the stations atmosphere. Loss mass experiments of the materials exposed in real time in the electric stations, soil potential monitoring, soil resistivity measurement, soil chemical analysis, and micrographic and chemical analysis of the materials after exposure in the study sites were performed. The loss mass experiments were performed using the International Organization of Standardization, ISO, 8407, 8565 e 9223 a 9227. The soil resistivity was determined using the Wenner method and the micrographs and chemical analysis of the corrosion products were obtained using scanning electron microscopy and energy dispersive spectroscopy, respectively Results showed significant change in the mass of steel and cooper, mainly in the stations located on the coast. Although the corrosive agents are present in the soil, the high corrosion rates on the coast were strongly associated with the marine atmosphere. All station soils presented high resistivity, which implies low aggressiveness to metallic materials. With these conclusions, it is evident that the procedures and precautions related to corrosion of the metallic components exposed to conditions of extreme aggressiveness, such as those in the presence of chloride ions and solid particulates, cannot be the same as the ones used for the atmospheres free of these components