Kinetic energy harvesting

This paper reviews kinetic energy harvesting as a potential localised power supply for wireless applications. Harvesting devices are typically implemented as resonant devices of which the power output depends upon the size of the inertial mass, the frequency and amplitude of the driving vibrations, the maximum available mass displacement and the damping. Three transduction mechanisms are currently primarily employed to convert mechanical into electrical energy: electromagnetic, piezoelectric and electrostatic. Piezoelectric and electrostatic mechanisms are best suited to small size MEMS implementations, but the power output from such devices is at present limited to a few microwatts. An electromagnetic generator implemented with discrete components has produced a power 120 ?W with the highest recorded efficiency to date of 51% for a device of this size reported to date. The packaged device is 0.8 cm3 and weighs 1.6 grams. The suitability of the technology in space applications will be determined by the nature of the available kinetic energy and the required level of output power. A radioactively coupled device may present an opportunity where suitable vibrations do not exist

Screen printed flexible Bi2Te3-Sb2Te3 based thermoelectric generator

This paper reports the fabrication and testing of Bismuth Tellurium (Bi2Te3) – Antimony Tellurium (Sb2Te3) based thermocouples using screen printing technology. In this study, screen printable thermoelectric pastes were developed and the transport properties of cured material were measured. The dimension of each planer thermoleg is 39.3 mm × 3 mm with a thickness of 67 µm for Bi2Te3 leg and 62 µm for Sb2Te3 leg. A single thermocouple with this dimension can generate a voltage of 6 mV and a peak output power of 48 nW at a temperature difference of 20°C. The calculated Seebeck coefficient of a single thermocouple is in the range of 262 to 282 µV/K. The Seebeck coefficient at room temperature were measured to be -134 to -119 µV/K and 128 to 134 µV/K for Bi2Te3 and Sb2Te3 respectively. This work demonstrates that the low-cost screen printing technology and low-temperature materials are promising for the fabrication of flexible thermoelectric generators (TEGs)

Flexible screen printed thick film thermoelectric generator with reduced material resistivity

This work presents a flexible thick-film Bismuth Tellurium/Antimony Tellurium (BiTe/SbTe) thermoelectric generator (TEG) with reduced material resistivity fabricated by screen printing technology. Cold isostatic pressing (CIP) was introduced to lower the resistivity of the printed thermoelectric materials. The Seebeck coefficient (alpha) and the resistivity (rho) of printed materials were measured as a function of applied pressure. A prototype TEG with 8 thermocouples was fabricated on flexible polyimide substrate. The dimension of a single printed element was 20 mm × 2 mm × 78.4 µm. The coiled-up prototype produced a voltage of 36.4 mV and a maximum power of 40.3 nW from a temperature gradient of 20 °C

Reseña: La Universidad de Córdoba en tiempos de reformas (1701-1810). De Silvano Benito Moya, 2011

El objetivo de la presente trabajo es reseñar el trabajo que ha realizado el Doctor Silvano Benito Moya en su reciente libro: La Universidad de Córdoba en tiempos de reformas (1701-1810).Fil: Perrupato, Sebastian Domingo. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Screen printed fabric electrode array for wearable functional electrical stimulation

Functional electrical stimulation (FES) activates nerves using electrical currents, and is widely used in medical applications to assist movement of patients with central nervous system lesions. The recent emergence of small electrode arrays enables greater muscle selectivity and reduces fatigue compared to the use of traditional large electrodes; however existing fabrication techniques are expensive and have limited flexibility and comfort which limits patient uptake. This work presents a screen printed flexible and breathable fabric electrode array (FEA) which consists of four printed functional layers. Successful operation has been demonstrated by stimulating an optimised selection of electrodes in order to achieve clinically relevant reference postures (‘pointing’, ‘pinch’ and ‘open hand’). The materials with skin contact used in FEA have been cytotoxicity tested to establish that they are biocompatible. The FEA demonstrates the potential for printable polymer materials to realise comfortable, wearable and cost effective functional systems in healthcare applications

A PZT multilayer actuator for ultrasonic applications

In many MEMS applications there is a requirement for actuating a structure. This paper describes a method of generating acoustic power from a PZT based thick-film structure which gives output power and electrical efficiencies at least as good as, and in some cases better than bulk PZT in the same application