This paper reports on an innovative electromagnetic energy harvester for autonomous switches relying on a rotating magnet driven by magnetic launchers, and combined with a ferromagnetic circuit and a coil to turn the variation of magnetic flux induced by the rotating magnet into electricity. The device is able to operate on forward and backward translation movements. The energy harvester has been modeled, optimized, manufactured, characterized and integrated into a mechanical actuation system to form a complete autonomous switch that will be commercially available. The experimental output energy reaches 1.235 mJ (350 µ J cm −3 ) which is among the highest output energies and energy densities reached on autonomous switches in the state of the art. The electromechanical conversion efficiency is 56%, which is excellent for an energy harvester, and obtained thanks to the topology chosen for the electromagnetic converter. The energy harvester is finally connected to a diode-bridge-capacitor circuit to supply the RF emission of the commands with a Zigbee Green Power ® transmitter.
This study presents an analysis of the results of a survey carried out by the International Electrotechnical Commission (IEC), Systems Evaluation Group 4 – low-voltage direct current (LVDC) applications, distribution and safety for use in Developed and Developing Economies (IEC SEG4). The survey covers topics from the stakeholder activities to the role of LVDC technology in electricity access. The focus is aimed at analysis of the results related to market prospects, the readiness and needs to develop standardisation, and the inputs received for standardisation development.
Nursing homes for older adults are increasingly confronted with older persons with long-term care needs and increased dependence while care staff number is increasingly restricted [1]. The e-monitor’age project aims at improving organization of care, well-being and security of residents. It is based on the development of a system of intelligent supervision which aims at improving the global efficiency of these establishments in order to allow an increased availability of the care staff. The development of this technology is based on a participative approach: the end-users needs are the starting point. Three focus groups were organized in each nursing home which participates to the project in order to collect the needs of the future users: medical and direction staff. The collected data were then analyzed and allowed to write the functional specifications of the project. Focus groups highlighted that help to supervision of the residents in difficult situations is essential and that the feeling of insecurity and need of support are major at night. Three objectives were retained for the development of the system: security of residents, discomfort and prevention on the long-term. The major originality of this work is the multidisciplinary approach: the project involves academic researchers, industrialists and medical staff. This participative conception is based on a close collaboration between all the actors. One of the most important factors for a successful development of such technology is the analysis of end-users needs [2]. Unfortunately such a work which actively involves medical staff is very rare [3], that's why our project is particularly original.
With the constantly increasing use of fluorescent lighting, more and more important and irreversible weldings of contacts occur inside low voltage electric apparatus and in particular inside switches. The aim of this study is to understand and avoid this phenomena. We used an "experiment design" upon the Taguchi method to quantify the influence of the following factors: composition of contact materials, curvature radius of contact parts, assembly method of contact parts on support, contact force. Each of the above factors was considered at three different values which enabled us to apply the study to a L9 matrix. The influence of each factor was estimated with the following criteria applied to the contacts tested: number of weldings, erosion loss and temperature rise. The tests are completed with bounce duration and arc energy measurements. Electrical tests were made according to testing conditions of standard CEI 669-1 with a R-L-C load at 230 V, 10 A. The microcomputer driven mechanical testing equipment is described. Results show that the contact force is the most influent parameter and that the asymmetrical combination of AgNi as fixed contact and AgSnO/sub 2/ as movable contact will cause the lowest number of weldings.
Coronary flow reserve, exercise thallium-201 scintigraphy and exercise radionuclide ventriculography were compared in 18 patients with chest pain and angiographically normal coronary arteries. Regional exercise thallium-201 perfusion was abnormal in three patients, regional exercise wall motion was abnormal in three other patients and results of both tests were abnormal in one additional patient. Left ventricular ejection fraction responses were abnormal in five of these seven patients. The coronary flow reserve of arterial distributions with abnormal perfusion or regional dysfunction was significantly lower than that of distributions associated with normal radionuclide results (1.42 +/- 0.23 versus 2.58 +/- 0.83, p less than 0.001). All patients with abnormal scintigraphic results had low coronary flow reserve (less than 1.95) in at least one distribution. Perfusion abnormalities appeared to be more localized in the arterial distributions with the lowest flow reserve. Only two patients had low flow reserve (less than 1.95) with normal scintigraphic results; both were hypertensive. These data suggest that abnormal exercise scintigraphic findings in patients with angiographically normal coronary arteries and chest pain are indicative of true blood flow or perfusion abnormalities.
