1,721,036 research outputs found
Li-Ion Battery-Supercapacitor Hybrid Storage System for a Long Lifetime, Photovoltaic-Based Wireless Sensor Network
No full textThis paper proposes a power management architecture that utilizes both supercapacitor cells and a lithium battery as energy storages for a photovoltaic (PV)-based wireless sensor network. The supercapacitor guarantees a longer lifetime in terms of charge cycles and has a large range of operating temperatures, but has the drawback of having low energy density and high cost. The lithium battery has higher energy density but requires an accurate charge profile to increase its lifetime, feature that cannot be easily obtained supplying the wireless node with a fluctuating source as the PV one. Combining the two storages is possible to obtain good compromise in terms of energy density. A statistic analysis is used for sizing the storages and experimental results with a 5-W PV energy source are reported
Supercapacitor-based Hybrid Storage Systems for Energy Harvesting in Wireless Sensor Networks
No full textRoles of Solar Power from Space for Europe: Space Exploration and Combinations with Terrestral Solar Plants Concepts
No full text
Leaving home: a comparative analysis of ECHP data
No full textWe use three waves of the European Community Household Panel (ECHP) to analyse the impact of employment, earnings, household income, and welfare on young adults' decision to leave the parental home. In particular we investigate the importance of these income sources in different welfare settings. We use a simultaneous equation approach to control for unobserved heterogeneity and left censoring. We find employment and income to be very important factors in the decisions of young adults to leave home in the Southern European welfare state. For the Continental European welfare states the results are more mixed. Employment and income are still important factors, but the effects are less clear and there are significant variations. In the Social Democratic welfare states, the effect of employment and income appears negligible. The effect is also modest in the UK (the Liberal Market state), a finding we attribute to the educational system
Low-Power Energy Harvesting Solutions for Wiegand Transducers
No full textThis paper analyzes different circuit solutions employing Wiegand magnetic sensors as energy harvesters for supplying lowpower
electronic equipment. Wiegand sensors release a ~10us voltage pulse several volts wide when subject to an external, time-varying magnetic field independently on the magnetic flux variation rate. When optimally loaded, a Wiegand device is capable of up to ~100nJ/pulse delivered energy. Due to the sharpness of the magnetic transition, pulse generation occurs regardless of how slow the magnetic field variation is, an attractive feature that enables its use in energy harvesting scenarios even when low-frequency sources are considered. Aim of this work is to investigate the use of Wiegand sensors as small scale energy sources, and discuss and compare low-power harvesting circuits for efficiently interfacing the sensor with a fixed DC bus with a typical voltage range of 3.3V to 5V
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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